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Energy/Environment/Cost/Other Benefits: " An efficient tube mill system consumes about 13 kWh/t. Replacing the tube mill by a wash mill would reduce electricity consumption to 5 to 7 kWh/t17 at comparable investment and operation costs as a tube mill system (Cembureau, 1997. Best Available Techniques for the Cement Industry, Brussels: Cembureau). " When replacing a tube mill, a wash mill should be considered as an alternative, reducing electricity consumption for raw grinding by 5 to 7 kWh/t or 40 to 60%. < f(  B~ XPP? ]4@~\ ) gH wESEAJ(` <Raw Meal Process Control for Vertical Mills (Dry process) Description: The main difficulty with existing vertical roller mills are vibration trips. Operation at high throughput makes manual vibration control difficult. When the raw mill trips, it cannot be started up for one hour, until the motor windings cool. A model predictive multivariable controller maximizes total feed while maintaining a target residue and enforcing a safe range for trip-level vibration. The first application eliminated avoidable vibration trips (which were 12 per month prior to the control project). Energy/Environment/Cost/Other Benefits: " Increase in throughput of six percent with a corresponding reduction in specific energy consumption of six percent (Martin, G. and S. McGarel, 2001.  Automated Solution, International Cement Review, February 2001, pp.66-67.) or 0.8 to 1.0 kWh/tonne of raw material (Cembureau, 1997. Best Available Techniques for the Cement Industry, Brussels: Cembureau). <*  B~ XPP?-]4@~ ) 98mDaCARt  <High-efficiency Classifiers/Separators (Dry Process) Description: A recent development in efficient grinding technologies is the use of high-efficiency classifiers or separators. Classifiers separate the finely ground particles from the coarse particles. The large particles are then recycled back to the mill. High efficiency classifiers can be used in both the raw materials mill and in the finish grinding mill. Standard classifiers may have a low separation efficiency, leading to the recycling of fine particles and resulting in to extra power use in the grinding mill. Various concepts of high-efficiency classifiers have been developed , . In high-efficiency classifiers, the material stays longer in the separator, leading to sharper separation, thus reducing over-grinding. Energy/Environment/Cost/Other Benefits: " Electricity savings through implementing high-efficiency classifiers are estimated to be 8% of the specific electricity use13. " Case studies have shown a reduction of 2.8 to 3.7 kWh/t raw material (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada. Sssegger, A., 1993. Separator-Report '92 Proc. KHD Symposium '92, Volume 1 Modern Roller Press Technology, KHD Humboldt Wedag, Cologne, Germany). " Replacing a conventional classifier by a high-efficiency classifier has led to 15% increases in the grinding mill capacity13 and improved product quality due to a more uniform particle size15, both in raw meal and cement. " The better size distribution of the raw meal may lead to fuel savings in the kiln and improved clinker quality. " Investment costs are estimated to be $2.2/annual t raw material production (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada). Case Studies: " In 1990, Tilbury Cement (Delta, British Columbia, Canada) modified a vertical roller mill with a high-efficiency classifier increasing throughput and decreasing electricity use (Salzborn, D. and A. Chin-Fatt, 1993.  Operational Results of a Vertical Roller Mill Modified with a High Efficiency Classifier Proc. 35th IEEE Cement Industry Technical Conference, Toronto, Ontario, Canada, May 1993). <*   BP XPP?]4@P)  rD'x7 ]<Use of Roller Mills (Dry Process) Description: Traditional ball mills used for grinding certain raw materials (mainly hard limestone) can be replaced by high-efficiency roller mills, by ball mills combined with high-pressure roller presses, or by horizontal roller mills. The use of these advanced mills saves energy without compromising product quality. Various roller mill process designs are marketed. Energy/Environment/Cost/Other Benefits: " Energy savings of 6 to 7 kWh/t raw materials (Cembureau, 1997. Best Available Techniques for the Cement Industry, Brussels: Cembureau) are assumed through the installation of a vertical or horizontal roller mill. " An additional advantage of the inline vertical roller mills is that they can combine raw material drying with the grinding process by using large quantities of low grade waste heat from the kilns or clinker coolers (Venkateswaran, S.R. and H.E. Lowitt. 1988. The U.S. Cement Industry, An Energy Perspective, U.S. Department of Energy, Washington D.C., USA) . " Investments are estimated to be $5.5/t raw material (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada). Case Studies: " Arizona Portland Cement (Rillito, Arizona, U.S.) installed a raw material grinding roller mill in 1998, increasing throughput, flexibility, and raw meal fineness and reducing electricity (De Hayes, L.J., 1999.  Flexibility, Availability and Maintenance Concept for the Quadropol , Polysius Teilt Mit No. 208, pp.33-38, Krupp Polysius, Germany). " Xinxiang Cement Company, Henan province installed a roller mill in its cement facility for 80 ton/hour. Electricity consumption was 15.4kWh/tonne (Presentation by Allbest Creative Development Ltd. Information available at: http://www.cement-hightech.com/files/allbest-cement.pdf). <"]a-  B XPP?d]4@) c/֐MH;wOp < Efficient Transport Systems for Raw Materials Preparation (Dry Process) Description: Transport systems are required to convey powdered materials such as kiln feed, kiln dust, and finished cement throughout the plant. These materials are usually transported by means of either pneumatic or mechanical conveyors. Mechanical conveyors use less power than pneumatic systems. Conversion to mechanical conveyors is cost-effective when replacement of conveyor systems is needed to increase reliability and reduce downtime. Energy/Environment/Cost/Other Benefits: " The average energy savings are estimated to be 1 to 2.0 kWh/t raw material with a switch to mechanical conveyor systems . " Installation costs for the system are approximately $3/t raw material production (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada). Case Studies: " Birla Cement Works, Chittorgarh Company in India replaced the pneumatic transport systems for kiln feeds with mechanical transport systems and found a power savings of 1.24 kWh/t clinker at a cost of 15.3 INR/t clinker (2.64 RMB/ t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175340468.27/view). " Chittor Cement Works (Chittorgarh Company in India) replaced the pneumatic transport system by a mechanical system in homogenization silos for two silos (for two kiln feeds) resulting in power savings of 2.35 kWh/t clinker at a cost of 10 INR/t clinker (1.7 RMB/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175340468.27/view). < "a0  B XPP?G]4@) 7^aIJ*#KV ]G  <=Raw Meal Blending (Homogenizing) Systems (Dry Process) Description: To produce a good quality product and to maintain optimal and efficient combustion conditions in the kiln, it is crucial that the raw meal is completely homogenized. Quality control starts in the quarry and continues to the blending silo. On-line analyzers for raw mix control are an integral part of the quality control system (Fujimoto, S., 1993.  Modern Technology Impact on Power Usage in Cement Plants, Proc. 35th IEEE Cement Industry Technical Conference, Toronto, Ontario, Canada, May 1993. Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada). Most plants use compressed air to agitate the powdered meal in so-called air-fluidized homogenizing silos. Older dry process plants use mechanical systems, which simultaneously withdraw material from six to eight different silos at variable rates2. Modern plants use gravity-type homogenizing silos (or continuous blending and storage silos) reducing power consumption. In these silos, material funnels down one of many discharge points, where it is mixed in an inverted cone. Gravity-type silos may not give the same blending efficiency as air-fluidized systems. Although most older plants use mechanical or air-fluidized bed systems, more and more new plants seem to have gravity-type silos, because of the significant reduction in power consumption (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada). Energy/Environment/Cost/Other Benefits: " Operating compressed air to agitate the powdered meal in so-called air-fluidized homogenizing silos uses 1.1 to 1.5 kWh/t raw meal. Older dry process plants using mechanical systems use 2.2 to 2.6 kWh/t raw meal. Modern plants using gravity-type homogenizing silos (or continuous blending and storage silos) reduce power consumption; energy savings are estimated to be 1.0 to 2.5 kWh/t raw meal (Fujimoto, S., 1993.  Modern Technology Impact on Power Usage in Cement Plants, Proc. 35th IEEE Cement Industry Technical Conference, Toronto, Ontario, Canada, May 1993. Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada. Alsop, P.A. and J.W. Post. 1995. The Cement Plant Operations Handbook, (First edition), Tradeship Publications Ltd., Dorking, UK. Cembureau, 1997. Best Available Techniques for the Cement Industry, Brussels: Cembureau. Gerbec, R., 1999. Fuller Company. Personal Communication). " Silo retrofit options are cost-effective when the silo can be partitioned with air slides and divided into compartments which are sequentially agitated, as opposed to the construction of a whole new silo system (Gerbec, R., 1999. Fuller Company. Personal Communication). " Costs for the silo retrofit are estimated to be $3.7/t raw material, assuming $550K per silo and an average capacity of 150,000 tonnes annual capacity. <;   B XPP?@b]4@H) T£}JN@r <New Efficient Coal Separator for Fuel Preparation Description: In a closed circuit system, larger coal particles are separated from gas and finer coal particles in a classifier or separator. There are static classifiers with a fixed geometry, classifiers with adjustable geometry, and dynamic high efficiency classifiers. Replacing the separator in the coal mill circuit with an efficient grit separator can save energy. Energy/Environment/Cost/Other Benefits: " See case studies for information on energy savings. Case Studies: " Birla Vikas Cement Works installed a new efficient modified grit separator in their coal mill and found electricity savings of 0.26 kWh/t clinker (estimating ratio of coal to clinker of 0.097, or 2.7 kWh/t coal) at a cost of 0.48 INR/t clinker (0.08 RMB/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175367790.14/view). <a  B| XPP?@]4@|4)  :D#Xg  <5Roller Mills for Fuel Preparation Description: Coal is the most used fuel in the cement industry, and the main fuel for the vast majority of clinker kilns in the China. Fuels preparation is most often performed on-site. Fuels preparation may include crushing, grinding and drying of coal. Coal is shipped wet to prevent dust formation and fire during transport. Passing hot gasses through the mill combines the grinding and drying. Coal roller mills are available for throughputs of 5.5 to 220 t/hour. Coal grinding roller mills can be found in many countries around the world, for example, Brazil, Canada, China, Denmark, Germany, Japan and Thailand. Vertical roller mills have been developed for coal grinding, and are used by over 100 plants around the world (Cembureau, 1997. Best Available Techniques for the Cement Industry, Brussels: Cembureau). Energy/Environment/Cost/Other Benefits: " An impact mill would consume around 45 to 60 kWh/t and a tube mill around 25 to 26 kWh/t (total system requirements) (Cembureau, 1997. Best Available Techniques for the Cement Industry, Brussels: Cembureau). Waste heat of the kiln system (for example the clinker cooler) can be used to dry the coal if needed. " Advantages of a roller mill are that its ability to handle larger sizes of coal (no pre-crushing needed) and coal types with a higher humidity and to manage larger variations in throughput. However, tube mills are preferred for more abrasive coal types. " Electricity consumption for a vertical roller mill is estimated to be 16 to 18 kWh/t coal (Bhatty, J. I., F. M. Miller and S. H. Kosmatka (eds.) 2004. Innovations in Portland Cement Manufacturing. Portland Cement Association). Electricity consumption for a bowl mill is 10 to 18 kWh/t coal, and for a ball mill 30 to 50 kWh/t coal (Cembureau, 1997. Best Available Techniques for the Cement Industry, Brussels: Cembureau). " The investment costs for a roller mill are typically higher than that of a tube mill or an impact mill, but the operation costs are also lower; roughly 20% compared to a tube mill and over 50% compared to an impact mill (Cembureau, 1997. Best Available Techniques for the Cement Industry, Brussels: Cembureau), estimating savings at 7 to 10 kWh/t coal. Case Studies: " Lehigh Portland Cement installed a vertical roller mill for coal grinding in 1999 at the Union Bridge, Maryland, U.S. plant. " Blue Circle cement has ordered a vertical roller mill for the new kiln line V at the Roberta plant in Calera, Alabama, U.S. It has a capacity of 41.3 ton/hr and was commissioned in early 2001. </   B XPP?r-]4@) BWLB$y <m Seal Replacement for Clinker Making in Rotary Kilns Description: Seals are used at the kiln inlet and outlet to reduce false air penetration, as well as heat losses. Seals may start leaking, increasing the heat requirement of the kiln. Most often pneumatic and lamella-type seals are used, although other designs are available (for example spring-type). Although seals can last up to 10,000 to 20,000 hours, regular inspection may be needed to reduce leaks. This technology is produced and available domestically in China (Cui, Y., 2004 and 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC)). Energy/Environment/Cost/Other Benefits: " Energy losses resulting from leaking seals may vary, but are generally relatively small. " Payback period for improved maintenance of kiln seals is estimated to be d"6 months (Canadian Lime Institute. 2001. Energy Efficiency Opportunity Guide in the Lime Industry, Office of Energy Efficiency, Natural Resources Canada, Ottawa, ON). Case Studies: " Philips Kiln Services (2001) reports that upgrading the inlet pneumatic seals at a relatively modern plant in India (Maihar Cement), reduced fuel consumption in the kiln by 0.4% (0.011 GJ/t clinker or 0.38 kgce/t clinker) (Philips Kiln Services. 2001. Philips Enviro-Seal, Case Study  M/S Maihar cement, Available at: http://www.kiln.com, accessed November 2001). <   BD XPP?s]4@D|) qCE5K < Optimize Heat Recovery/Upgrade Clinker Cooler for Clinker Making in Rotary Kilns Description: The clinker cooler drops the clinker temperature from 1200C down to 100C. The most common cooler designs are of the planetary (or satellite), traveling and reciprocating grate type. All coolers heat the secondary air for the kiln combustion process and sometimes also tertiary air for the precalciner (Alsop, P.A. and J.W. Post. 1995. The Cement Plant Operations Handbook, (First edition), Tradeship Publications Ltd., Dorking, UK). Reciprocating grate coolers are the modern variant and are suitable for large-scale kilns (up to 10,000 tpd). Grate coolers use electric fans and excess air. The highest temperature portion of the remaining air can be used as tertiary air for the precalciner. Rotary coolers (used for approximately 5% of the world clinker capacity for plants up to 2200 to 5000 tpd) and planetary coolers (used for 10% of the world capacity for plants up to 3300 to 4400 tpd) do not need combustion air fans and use little excess air, resulting in relatively lower heat losses (Buzzi, S. and G. Sassone. 1993. Optimization of Clinker Cooler Operation, Proc. VDZ Kongress 1993: Verfahrenstechnik der Zementherstellung Bauverlag, Wiesbaden, Germany: 296-304; Vleuten, F.P. van der. 1994. Cement in Development: Energy and Environment Netherlands Energy Research Foundation, Petten, The Netherlands). (For more information about grate coolers, see Conversion to Reciprocating Grate Cooler for Clinker Making in Rotary Kilns measure). Energy/Environment/Cost/Other Benefits: " Grate coolers may recover between 1.3 and 1.6 GJ/t (44 to 55 kgce/t) clinker sensible heat (Buzzi, S. and G. Sassone. 1993. Optimization of Clinker Cooler Operation, Proc. VDZ Kongress 1993: Verfahrenstechnik der Zementherstellung Bauverlag, Wiesbaden, Germany: 296-304). Heat recovery can be improved through reduction of excess air volume (Alsop, P.A. and J.W. Post. 1995. The Cement Plant Operations Handbook, (First edition), Tradeship Publications Ltd., Dorking, UK),control of clinker bed depth and new grates such as ring grates (Buzzi, S. and G. Sassone. 1993. Optimization of Clinker Cooler Operation, Proc. VDZ Kongress 1993: Verfahrenstechnik der Zementherstellung Bauverlag, Wiesbaden, Germany: 296-304; Lesnikoff, G. 1999. Hanson Cement, Cupertino, CA, personal communication). " Improving heat recovery efficiency in the cooler results in fuel savings, but may also influence product quality and emission levels. " Control of cooling air distribution over the grate may result in lower clinker temperatures and high air temperatures. " Additional heat recovery results in reduced energy use in the kiln and precalciner, due to higher combustion air temperatures. " Birch, (1990) notes a savings of 0.05 to 0.08 GJ/t (2 to 3 kgce/t) clinker through the improved operation of the grate cooler, while Holderbank, (1993) notes savings of 0.16 GJ/t (5.4 kgce/t) clinker for retrofitting a grate cooler (Birch, E. 1990. Energy Savings in Cement Kiln Systems Energy Efficiency in the Cement Industry (Ed. J. Sirchis), London, England: Elsevier Applied Science: 118-128. Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada). COWIconsult et al. (1993) note savings of 0.08 GJ/t (3 kgce/t) clinker but an increase in electricity use of 2.0 kWh/t clinker (COWIconsult, March Consulting Group and MAIN. 1993. Energy Technology in the Cement Industrial Sector, Report prepared for CEC - DG-XVII, Brussels, April 1992). " The costs of this measure are assumed to be half the costs of the replacement of the planetary with a grate cooler, or $0.22/annual tonne clinker capacity. " A recent innovation in clinker coolers is the installation of a static grate section at the hot end of the clinker cooler. This has resulted in improved heat recovery and reduced maintenance of the cooler. " Modification of the cooler would result in improved heat recovery rates of 2 to 5% over a conventional grate cooler. " I<nvestments are estimated to be $0.11 to $0.33/annual tonne clinker capacity (Young, G. 2002. Personal communication from Gerald I. Young, Penta Engineering Corp., St. Louis Missouri, March). <Pa  B XPP?s$-]4@) g[u|D*n.3 B < Optimize Heat Recovery/Upgrade Clinker Cooler for Clinker Making in Rotary Kilns Description: The clinker cooler drops the clinker temperature from 1200C down to 100C. The most common cooler designs are of the planetary (or satellite), traveling and reciprocating grate type. All coolers heat the secondary air for the kiln combustion process and sometimes also tertiary air for the precalciner (Alsop, P.A. and J.W. Post. 1995. The Cement Plant Operations Handbook, (First edition), Tradeship Publications Ltd., Dorking, UK). Reciprocating grate coolers are the modern variant and are suitable for large-scale kilns (up to 10,000 tpd). Grate coolers use electric fans and excess air. The highest temperature portion of the remaining air can be used as tertiary air for the precalciner. Rotary coolers (used for approximately 5% of the world clinker capacity for plants up to 2200 to 5000 tpd) and planetary coolers (used for 10% of the world capacity for plants up to 3300 to 4400 tpd) do not need combustion air fans and use little excess air, resulting in relatively lower heat losses (Buzzi, S. and G. Sassone. 1993. Optimization of Clinker Cooler Operation, Proc. VDZ Kongress 1993: Verfahrenstechnik der Zementherstellung Bauverlag, Wiesbaden, Germany: 296-304; Vleuten, F.P. van der. 1994. Cement in Development: Energy and Environment Netherlands Energy Research Foundation, Petten, The Netherlands). (For more information about grate coolers, see Conversion to Reciprocating Grate Cooler for Clinker Making in Rotary Kilns measure). Energy/Environment/Cost/Other Benefits: " Grate coolers may recover between 1.3 and 1.6 GJ/t (44 to 55 kgce/t) clinker sensible heat (Buzzi, S. and G. Sassone. 1993. Optimization of Clinker Cooler Operation, Proc. VDZ Kongress 1993: Verfahrenstechnik der Zementherstellung Bauverlag, Wiesbaden, Germany: 296-304). Heat recovery can be improved through reduction of excess air volume (Alsop, P.A. and J.W. Post. 1995. The Cement Plant Operations Handbook, (First edition), Tradeship Publications Ltd., Dorking, UK),control of clinker bed depth and new grates such as ring grates (Buzzi, S. and G. Sassone. 1993. Optimization of Clinker Cooler Operation, Proc. VDZ Kongress 1993: Verfahrenstechnik der Zementherstellung Bauverlag, Wiesbaden, Germany: 296-304; Lesnikoff, G. 1999. Hanson Cement, Cupertino, CA, personal communication). " Improving heat recovery efficiency in the cooler results in fuel savings, but may also influence product quality and emission levels. " Control of cooling air distribution over the grate may result in lower clinker temperatures and high air temperatures. " Additional heat recovery results in reduced energy use in the kiln and precalciner, due to higher combustion air temperatures. " Birch, (1990) notes a savings of 0.05 to 0.08 GJ/t (2 to 3 kgce/t) clinker through the improved operation of the grate cooler, while Holderbank, (1993) notes savings of 0.16 GJ/t (5.4 kgce/t) clinker for retrofitting a grate cooler (Birch, E. 1990. Energy Savings in Cement Kiln Systems Energy Efficiency in the Cement Industry (Ed. J. Sirchis), London, England: Elsevier Applied Science: 118-128. Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada). COWIconsult et al. (1993) note savings of 0.08 GJ/t (3 kgce/t) clinker but an increase in electricity use of 2.0 kWh/t clinker (COWIconsult, March Consulting Group and MAIN. 1993. Energy Technology in the Cement Industrial Sector, Report prepared for CEC - DG-XVII, Brussels, April 1992). " The costs of this measure are assumed to be half the costs of the replacement of the planetary with a grate cooler, or $0.22/annual tonne clinker capacity. " A recent innovation in clinker coolers is the installation of a static grate section at the hot end of the clinker cooler. This has resulted in improved heat recovery and reduced maintenance of the cooler. " Modification of the cooler would result in improved heat recovery rates of 2 to 5% over a conventional grate cooler. " I< nvestments are estimated to be $0.11 to $0.33/annual tonne clinker capacity (Young, G. 2002. Personal communication from Gerald I. Young, Penta Engineering Corp., St. Louis Missouri, March). Case Studies: " Binani Cement in India modified a clinker cooler for increased heat recovery and found fuel savings of 0.062 GJ/t clinker (2 kgce/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1159866250.93/view). <Wa  B  XPP?I]4@ ) H FAE"L { <Kiln Combustion System Improvements for Clinker Making in Rotary Kilns Description: Fuel combustion systems in kilns can be contributors to kiln inefficiencies with such problems as poorly adjusted firing, incomplete fuel burn-out with high CO formation, and combustion with excess air (Venkateswaran, S.R. and H.E. Lowitt. 1988. The U.S. Cement Industry, An Energy Perspective, U.S. Department of Energy, Washington D.C., USA). Improved combustion systems aim to optimize the shape of the flame, the mixing of combustion air and fuel and reducing the use of excess air. Various approaches have been developed. Lowes and Bezant, (1990) discuss advancements from combustion technology that improve combustion through the use of better kiln control. For rotary kilns, the Gyro-Therm technology was originally developed at the University of Adelaide (Australia), and can be applied to gas burners or gas/coal dual fuel. The Gyro-Therm burner uses a patented "precessing jet" technology. The nozzle design produces a gas jet leaving the burner in a gyroscopic-like precessing motion. This stirring action produces rapid large scale mixing in which pockets of air are engulfed within the fuel envelope without using high velocity gas or air jets. The combustion takes place in pockets within the fuel envelope under fuel rich conditions. This creates a highly luminous flame, ensuring good irradiative heat transfer. Energy/Environment/Cost/Other Benefits: " For rotary kilns, the Gyro-Therm technology improves gas flame quality while reducing NOx emissions. " Costs for the Gyro-Therm vary by installation. An average cost of $1/annual tonne clinker capacity is assumed based on reported costs in demonstration projects. Case Studies: " Fuel savings of up to 10% have been demonstrated for the use of flame design techniques to eliminate reducing conditions in the clinkering zone of the kiln in a Blue Circle plant (Lowes, T.M. and Bezant, K.W. 1990. Energy Management in the UK Cement Industry Energy Efficiency in the Cement Industry (Ed. J. Sirchis), London, England: Elsevier Applied Science). " One technique developed in the U.K. for flame control resulted in fuel savings of 2 to 10% depending on the kiln type (Venkateswaran, S.R. and H.E. Lowitt. 1988. The U.S. Cement Industry, An Energy Perspective, U.S. Department of Energy, Washington D.C., USA). " A demonstration project of the Gyro-Therm technology at an Adelaide Brighton plant in Australia found average fuel savings between 5 and 10% as well as an increase in output of 10% (Centre for the Analysis and Dissemination of Demonstrated Energy Technologies (CADDET), International Energy Agency. 1997. Revolutionary low-NOx high-efficiency gas burner, Sittard, the Netherlands: CADDET). " Another demonstration project of the Gyro-Therm technology at the Ash Grove plant in the U.S. (Durkee, Oregon) found fuel savings between 2.7% and 5.7% with increases in output between 5 and 9% (Centre for the Analysis and Dissemination of Demonstrated Energy Technologies (CADDET), International Energy Agency. 1997. Revolutionary low-NOx high-efficiency gas burner, Sittard, the Netherlands: CADDET. Videgar, R., Rapson, D. and Dhanjal, S., 1997. Gyro-therm Technology Boosts Cement Kiln Output, Efficiency and Cuts NOx Emissions. Proceedings 1997 IEEE/PCA Cement Industry Technical Conference XXXIX Conference Record, Institute of Electrical and Electronics Engineers: New Jersey). <A{   Bp XPP?*]4@p ) m`9NU7E{ i  <Low Temperature Heat Recovery for Power Generation for Clinker Making in Rotary Kilns Description: Despite government policies to promote adoption of the technology (through the China Medium and Long Term Energy Conservation Plan, for example), using low temperature waste heat for power generation has not been widely adopted by Chinese cements plants although 45 cement rotary kilns have already adopted this measure. Even many large-scale rotary kilns built after 2003 do not use this technology. Energy/Environment/Cost/Other Benefits: " Pan (2005) estimates a cost for imported (Japanese) technology of 18,000 to 22,000 RMB ($2,250 to $2,750) per kW with an installation capacity over 6 MW. " Chinese domestic technology was developed in 1996 and is currently available from three Chinese companies: Tianjin Cement Industry Design & Research Institute Co., Ltd., Zhongxin Heavy Machine Company, and Huaxiao Resource Co. Ltd. All three companies have on-going demonstration programs in Chinese cement plants. Installation cost of domestic technology and equipment is currently about 10,000 RMB ($1,250) per kW. " The installation cost would be a bit lower if kilns and generation system are constructed simultaneously. " For a 2000 tonne per day (730,000 annual tonne) kiln capacity, about 20 kWh/t clinker of electricity could be generated for an investment of 20 to 30 million RMB. " Generating capacity of domestic technology is approximated to be 24 to 32 kWh and foreign technology about 28 to 36 kWh. " Domestic technology could produce 35kWh/t of clinker while Japanese technology now produces 45 kWh/t of clinker. German technology is even better but no data is available. " Running time and required labor are approximately the same for foreign and domestic equipment. Case Studies: " The Anhui Ningguo cement plant, with funding from Japan , installed a power generation system on a 4000 tonne per day kiln cement production line and found electricity generated reached 39 kWh per tonne of clinker since operation began in 1998. " At China United Cement Company, two 6000 kW systems were installed for RMB 101.8 million, RMB 36 million of private capital and RMB 64 million of bank loans, equaling about RMB 8500 per kW. The electricity being generated is 79.8 kWh/t clinker. " Beijing Cement Ltd. also installed waste heat recovery equipment on its 2400 tpd and 3200 tpd kilns. Total capacity is now 7.5 MW and the total investment was RMB 47.43 million, equaling about 6,300 RMB per kW. Of this, 70% was provided by the Beijing Energy Investment Company. " In another demonstration project summarized by GEI (2005), the waste heat from two clinker kilns of Taishan Cement Ltd is to be used. The capacity of the two kilns is 5000 tonnes per day and 2500 tonnes per day. Operation was to begin on 1st Oct 2005; equipment has already been installed but is still under adjustment. Maximum capacity is designed at 13.2 MW and annual output of 95 GWh. Of this, 90.8 GWh would be supplied to cement production, accounting for more than 30% of the energy needs of cement production. " In May 2002, the Tianjin Cement Industry Design and Research Institute in cooperation with the Shanghai Wanan Enterprise Corporation began renovations on a 1350 tonne four-stage cyclone preheater kiln to generate low-temperature waste heat electricity. They installed domestic low temperature waste heat recovery technology, and the facility now generates over 1.8 MW of electricity, operating 7000 hours per year. Including the 10% electricity required to operate the system, the facility generates an additional 11.34 GWh annually. With an electricity price of 0.50 RMB/kWh, the Tianjin Cement plant found savings of 11 to 14 RMB per tonne of clinker. The operating cost is about 0.06 RMB/kWh and the payback period about 3 years. " Low-temperature waste heat recovery has been implemented at other plants, as well, including the 4000 tonne/day precalciner kiln at the Ningguo Cement Factory of the Conch Group and the Liuzhou Cement Factory. <MTa  BԂ XPP?}4Z]4@Ԃ ) 6ӶC*g[  <High Temperature Heat Recovery for Power Generation for Clinker Making in Rotary Kilns Description: Waste gas discharged from the kiln exit gases, the clinker cooler system, and the kiln pre-heater system all contain useful energy that can be converted into power. Energy/Environment/Cost/Other Benefits: " In the U.S., only in a long-dry kiln is the temperature of the exhaust gas sufficiently high to cost-effectively recover the heat through power generation (Technically, organic rankine cycles or Kalina cycles (using a mixture of water and ammonia) can be used to recover low-temperature waste heat for power production, but this is currently not economically attractive, except for locations with high power costs. In China, however, low temperature heat is being recovered; see previous measure for details). " Cogeneration systems can either be direct gas turbines that utilize the waste heat (top cycle), or the installation of a waste heat boiler system that runs a steam turbine system (bottom cycle). " This measure focuses on the steam turbine system since these systems have been installed in many plants worldwide and have proven to be economic (Steinbliss, E. 1990. Traditional and Advanced Concepts of Waste Heat Recovery in Cement Plants Energy Efficiency in the Cement Industry (Ed. J. Sirchis), London, England: Elsevier Applied Science; Jaccard, M.K. & Associates and Willis Energy Services Ltd. 1996. Industrial Energy End-Use Analysis and Conservation Potential in Six Major Industries in Canada. Report prepared for Natural Resources Canada, Ottawa, Canada; Neto, M. 1990. Waste Gas Heat Recovery in Cement Plants Energy Efficiency in the Cement Industry (Ed. J. Sirchis), London, England: Elsevier Applied Science). " Heat recovery has limited application for plants with in-line raw mills, as the heat in the kiln exhaust is used for raw material drying. " While electrical efficiencies are still relatively low (18%), based on several case studies power generation may vary between 11 and 25 kWh/t clinker (Steinbliss, E. 1990. Traditional and Advanced Concepts of Waste Heat Recovery in Cement Plants Energy Efficiency in the Cement Industry (Ed. J. Sirchis), London, England: Elsevier Applied Science; Neto, M. 1990. Waste Gas Heat Recovery in Cement Plants Energy Efficiency in the Cement Industry (Ed. J. Sirchis), London, England: Elsevier Applied Science. Scheuer, A. and Sprung, S., 1990. Energy Outlook in West Germany s Cement Industry. Energy Efficiency in the Cement Industry (Ed. J. Sirchis), London, England: Elsevier Applied Science.) " Electricity savings of 22 kWh/t clinker are assumed. " Installation costs for such a system are estimated to be at $2.2 to 4.4/annual tonne clinker capacity with operating costs of $0.22 to 0.33/t clinker (Jaccard, M.K. & Associates and Willis Energy Services Ltd. 1996. Industrial Energy End-Use Analysis and Conservation Potential in Six Major Industries in Canada. Report prepared for Natural Resources Canada, Ottawa, Canada). " In 1999, four U.S. cement plants cogenerated 486 million kWh (United States Geological Survey, 2001. Minerals Yearbook, Washington, D.C., USGS. Available at http://minerals.er.usgs.gov/minerals/). " In China, most high temperature waste heat is recycled to the preheated and precalciner. <E>   B8 XPP?:i]4@8h) mwO/ٚ  D< Conversion to Reciprocating Grate Cooler for Clinker Making in Rotary Kilns Description: Four main types of coolers are used in the cooling of clinker: (1) shaft; (2) rotary; (3) planetary; and, (4) reciprocating grate coolers. There are no longer any rotary or shaft coolers in operation in North America; in China, there are few if any rotary or shaft coolers (Cui, Y., 2004 and 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC)). However, some reciprocating grate coolers may still be in operation. The grate cooler is the modern variant and is used in almost all modern kilns. Energy/Environment/Cost/Other Benefits: " The advantages of the grate cooler are its large capacity (allowing large kiln capacities) and efficient heat recovery (the temperature of the clinker leaving the cooler can be as low as 83C, instead of 120 to 200C, which is expected from planetary coolers (Vleuten, F.P. van der. 1994. Cement in Development: Energy and Environment Netherlands Energy Research Foundation, Petten, The Netherlands). " Tertiary heat recovery (needed for precalciners) is impossible with planetary coolers, limiting heat recovery efficiency (Cembureau, 1997b. Best Available Techniques for the Cement Industry, Brussels: Cembureau). " Grate coolers recover more heat than do the other types of coolers. " For large capacity plants, grate coolers are the preferred equipment. For plants producing less than 500 tonnes per day the grate cooler may be too expensive (COWIconsult, March Consulting Group and MAIN. 1993. Energy Technology in the Cement Industrial Sector, Report prepared for CEC - DG-XVII, Brussels, April 1992). Replacement of planetary coolers by grate coolers is not uncommon (Alsop, P.A. and J.W. Post. 1995. The Cement Plant Operations Handbook, (First edition), Tradeship Publications Ltd., Dorking, UK). " Modern reciprocating coolers have a higher degree of heat recovery than older variants, increasing heat recovery efficiency to 60 to 71% (Bhatty, J. I., F. M. Miller and S. H. Kosmatka (eds.) 2004. Innovations in Portland Cement Manufacturing. Portland Cement Association), while reducing fluctuations in recuperation efficiency (i.e. increasing productivity of the kiln). " When compared to a planetary cooler, additional heat recovery is possible with grate coolers at an extra power consumption of approximately 3 to 6 kWh/t clinker (Bhatty, J. I., F. M. Miller and S. H. Kosmatka (eds.) 2004. Innovations in Portland Cement Manufacturing. Portland Cement Association. COWIconsult, March Consulting Group and MAIN. 1993. Energy Technology in the Cement Industrial Sector, Report prepared for CEC - DG-XVII, Brussels, April 1992; Vleuten, F.P. van der. 1994. Cement in Development: Energy and Environment Netherlands Energy Research Foundation, Petten, The Netherlands). The savings are estimated to be up to 8% of the fuel consumption in the kiln (Vleuten, F.P. van der. 1994. Cement in Development: Energy and Environment Netherlands Energy Research Foundation, Petten, The Netherlands). " Cooler conversion is generally economically attractive only when installing a precalciner, which is necessary to produce the tertiary air, or when expanding production capacity. " The cost of a cooler conversion is estimated to be between $.044 and $5.5/annual tonne clinker capacity, depending on the degree of reconstruction needed. " Annual operation costs increase by $0.11/t clinker (Jaccard, M.K. & Associates and Willis Energy Services Ltd. 1996. Industrial Energy End-Use Analysis and Conservation Potential in Six Major Industries in Canada. Report prepared for Natural Resources Canada, Ottawa, Canada). Case Studies: " In China, the Liulihe Cement Factory implemented a TCIDRI third generation grate cooler and achieved a heat recovery rate of over 72% on a 2500 tonne/day precalciner kiln (Institute of Technical Information for Building Materials Industry (ITIBMIC). 2004. Final Report on Cement Survey. Prepared for the United Nations Industrial Developm<k ent Organization (UNIDO) for the Contract Entitled Cement Sub-sector Survey for the Project Energy Conservation and GHG Emissions Reduction in Chinese TVEs-Phase II. Contract no. 03/032/ML, P.O. No. 16000393, September 9). This aerated beam grate cooler also saves water by replacing the water spray cooling with air cooling (Institute of Technical Information for Building Materials Industry (ITIBMIC). 2004. Final Report on Cement Survey. Prepared for the United Nations Industrial Development Organization (UNIDO) for the Contract Entitled Cement Sub-sector Survey for the Project Energy Conservation and GHG Emissions Reduction in Chinese TVEs-Phase II. Contract no. 03/032/ML, P.O. No. 16000393, September 9). " The Lafarge Alpena, Michigan (U.S.) Plant changed its grate cooler to accommodate an increase in production rate of 10% and combat rising maintenance costs, obsolete parts, and poor operational efficiencies of the current grate cooler. They replaced the existing oscillating grate cooler with a new efficient grate cooler that utilizes air beam technology. Audited cooler losses were 207 MJ/t (7.06 kgce/t). Power consumption was 6.6 kWh/t. Clinker discharge temperatures after the breaker are lower than 56C above ambient. The fuel consumption reduction resulting from the cooler installation was approximately 3% (Bump, J. A. of LaFarge Corp. (1996). New cooler installed at Lafarge Alpena Plant: Fuller Controlled Flow Grate (CFG) Clinker Cooler (Cement Plant). Cement Industry Technical Conference, 1996. XXXVIII Conference Record., IEEE/PCA. April 14-18, 1996). <kDa  B XPP?]4@T) а YLHnB' <Efficient Kiln Drives for Clinker Making in Rotary Kilns Description: A substantial amount of power is used to rotate the kiln. The highest efficiencies are achieved using a single pinion drive with an air clutch and a synchronous motor (Regitz, John. 1996. Evaluation of Mill Drive Options IEEE Transactions on Industry Applications 3 32: 653). Energy/Environment/Cost/Other Benefits: " The system would reduce power use for kiln drives by a few percent, or roughly 0.55 kWh/t clinker at slightly higher capital costs (+6%). " More recently, the use of alternate current (AC) motors is advocated to replace the traditionally used direct current (DC) drive. The AC motor system may result in slightly higher efficiencies (0.5  1% reduction in electricity use of the kiln drive) and has lower investment costs (Holland, M. 2001. AC DC Kilns, Proc. 2001 IEEE-IAS/PCA Cement Industry Technical Conference: 75- 84). " Replacing older motors with high-efficiency ones may reduce power costs by 2 to 8%. <  B XPP?i]4@) I@J& < Conversion of Long Dry Kilns to Preheater/Precalciner Kilns for Clinker Making in Rotary Kilns Description: A long dry kiln can be upgraded to the current state of the art multi-stage preheater/precalciner kiln. Energy/Environment/Cost/Other Benefits: " Energy savings are estimated to be 1.4 GJ/t clinker (48 kgce/t clinker) for the conversion, reflecting the difference between the average dry kiln specific fuel consumption and that of a modern preheater, pre-calciner kiln based on a study of the Canadian cement industry and the retrofit of an Italian plant (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada.; Sauli, R.S. 1993. Rotary Kiln Modernization and Clinker Production Increase at Testi Cement Plant of S.A.C.C.I. Spa., Italy Proc. KHD Symposium '92, Modern Burning Technology, KHD Humboldt Wedag, Cologne, Germany). " Costs have been estimated to range from $8.6/t clinker capacity (Jaccard, M.K. & Associates and Willis Energy Services Ltd. 1996. Industrial Energy End-Use Analysis and Conservation Potential in Six Major Industries in Canada. Report prepared for Natural Resources Canada, Ottawa, Canada) to 23 to 29/t clinker capacity (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada.; Sauli, R.S. 1993. Rotary Kiln Modernization and Clinker Production Increase at Testi Cement Plant of S.A.C.C.I. Spa., Italy Proc. KHD Symposium '92, Modern Burning Technology, KHD Humboldt Wedag, Cologne, Germany) for a pre-heater, pre-calciner kiln. <  Bd XPP?>3]4@d) $'AWC#1 <1Increasing Number of Preheater Stages in Rotary Kilns Description: Increasing the number of stages of the preheater will decrease heat losses and increase efficiency of the kiln. Energy/Environment/Cost/Other Benefits: " By installing new preheaters, the productivity of the kiln will increase, due to a higher degree of pre-calcination (up to 30 to 40%) as the feed enters the kiln. " Energy savings depend strongly on the specific energy consumption of the dry process kiln to be converted as well as the number of preheaters to be installed. " See other Rotary Kiln Preheater/Precalciner measures for additional benefits Case Studies: " Vikram Cement in India upgraded a preheater from five to six stages (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175350601.7/view). They found fuel savings of 0.111 GJ/t (3.8 kgce/t) with increased electricity use of 1.17 kWh/t. Capital costs were $110.5 INR per tonne of clinker (19.RMB/t clinker). < e  BȄ XPP?-%]4@Ȅ) Z9|w)@Le]  <Dry Process Upgrade to Multi-Stage Preheater Kiln for Clinker Making in Rotary Kilns Description: Older dry kilns may only preheat in the chain section of the long kiln, or may have single- or two-stage preheater vessels. Installing multi-stage suspension preheating (i.e. four- or five-stage) may reduce the heat losses and thus increase efficiency. Modern cyclone or suspension preheaters also have a reduced pressure drop, leading to increased heat recovery efficiency and reduced power use in fans (see low pressure drop cyclones measure). Energy/Environment/Cost/Other Benefits: " By installing new preheaters, the productivity of the kiln will increase, due to a higher degree of pre-calcination (up to 30 to 40%) as the feed enters the kiln. " Also, the kiln length may be shortened by 20 to 30% thereby reducing radiation losses (Van Oss, H. 1999. Personal Communication. U.S. Geological Survey, February 9). " As the capacity increases, the clinker cooler may have to be adapted to be able to cool the large amounts of clinker. " The conversion of older kilns is attractive when the old kiln needs replacement and a new kiln would be too expensive, assuming that limestone reserves are adequate. " Energy savings depend strongly on the specific energy consumption of the dry process kiln to be converted as well as the number of preheaters to be installed. Energy savings are estimated to be 0.9 GJ/t clinker (31 kgce/t clinker) for the conversion which reflects the difference between the average dry kiln specific fuel consumption and that of a modern preheater kiln (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada). " Specific costs are estimated to be $39 to 41/annual tonne clinker capacity for conversion to a multi-stage preheater kiln63 or $28/annual tonne clinker capacity to install suspension pre-heaters (Vleuten, F.P. van der. 1994. Cement in Development: Energy and Environment Netherlands Energy Research Foundation, Petten, The Netherlands). Case Studies: " Cement kilns in the former German Democratic Republic were rebuilt by Lafarge to replace four dry process kilns originally constructed in 1973 and 1974. In 1993 and 1995, three kilns were equipped with four-stage suspension preheaters. The specific fuel consumption was reduced from 4.1 to 3.6 GJ/t clinker (140 to 123 kgce/t clinker), while the capacity of the individual kilns was increased from 1650 to 2500 tpd (Duplouy, A. and J. Trautwein. 1997. Umbau und Optimierung der Drehofenanlagen im Werk Karsdorf der Lafarge Zement Gmbh. ZKG International 4 50: 190-197). In the same project, the power consumption was reduced by 25%, due to the replacement of fans and the finish grinding mill. <4    B, XPP?-~]4 @, ) }}i=Kw0 < Installation or Upgrading of a Preheater to a Preheater/Precalciner Kiln for Clinker Making in Rotary Kilns Description: An existing preheater kiln may be converted to a multi-stage preheater/precalciner kiln by adding a precalciner and, when possible an extra preheater. The addition of a precalciner will generally increase the capacity of the plant, while lowering the specific fuel consumption and reducing thermal NOx emissions (due to lower combustion temperatures in the precalciner). Using as many features of the existing plant and infrastructure as possible, special precalciners have been developed by various manufacturers to convert existing plants, for example Pyroclon-RP by KHD in Germany. Generally, the kiln, foundation and towers are used in the new plant, while cooler and preheaters are replaced. Cooler replacement may be necessary in order to increase the cooling capacity for larger production volumes. Older precalciners can be retrofitted for energy efficiency improvement and NOx emission reduction. Many precalciner kilns have been constructed from 2001 and are about 10 to 20% imported and 80 to 90% domestic (Cui, Y., 2004 and 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC)). Domestic technology, made by a few leading manufacturers in China, costs roughly 20 to 33% of the cost of imported technology but doesn t last as long. Most companies are adopting domestic technologies. Domestic technology, however, is not available for kiln sizes over 5000 tonne per day (Wang, Yanjia of Tsinghua University, Beijing, China. 2006b. Personal written communication). Energy/Environment/Cost/Other Benefits: " Fuel savings will depend strongly on the efficiency of the existing kiln and on the new process parameters (for example degree of precalcination, cooler efficiency). " A multi-stage preheater/precalciner kiln uses approximately 3 GJ/t clinker (100 kgce/t clinker) (European Commission (EC). 2000. Directorate-General Joint Research Centre, Institute for Prospective Technological Studies. Integrated Pollution Prevention and Control (IPPC): Reference Document on Best Available Techniques in the Cement and Lime Manufacturing Industries. Seville, Spain. March). " Average savings of new precalciners can be 0.4 GJ/t clinker (14 kgce/t clinker) (Sauli, R.S. 1993. Rotary Kiln Modernization and Clinker Production Increase at Testi Cement Plant of S.A.C.C.I. Spa., Italy Proc. KHD Symposium '92, 2 Modern Burning Technology, KHD Humboldt Wedag, Cologne, Germany). " The cost of adding a precalciner and suspension preheaters is estimated to be between $9.4 to $28 U.S./ tonne clinker capacity (Vleuten, F.P. van der. 1994. Cement in Development: Energy and Environment Netherlands Energy Research Foundation, Petten, The Netherlands. Jaccard, M.K. & Associates and Willis Energy Services Ltd. 1996. Industrial Energy End-Use Analysis and Conservation Potential in Six Major Industries in Canada. Report prepared for Natural Resources Canada, Ottawa, Canada). " Increased production capacity is likely to save considerably in operating costs, estimated to be $1.1/t clinker Case Studies: " Retrofitting the precalciner at the Lengerich plant of Dyckerhoff Zement (Germany) in 1998 reduced NOx emissions by almost 45% (Mathe, H. 1999. NOx Reduction with the Prepol MSC Process at the Lengerich Plant of Dyckerhoff Zement GmbH, Polysius Teilt Mit, 208: 53-55, Krupp Polysius, Germany). Similar emission reductions have been found at kilns in Germany, Italy and Switzerland (Menzel, K. 1997. Experience with the Prepol-MSC Calciner and a Review of the Possibilities it Offers, Polysius Teilt Mit, 198: 29-33, Krupp Polysius, Germany). " Ash Grove s Durkee, Oregon (U.S.) original 1979 plant installed new preheaters and a precalciner in 1998, expanding production from 1500 tonnes/day to 2500 tonnes/day. The reconstruction reduced fuel consumption by 0.16 to 0.7 GJ/t clinker (5.4 to 24 kgce/t clinker) (Hrizuk, M.J. 1999. Expansion is Key at Durkee, Internatio<nal Cement Review, May.), while reducing NOx emissions. " Capitol Cement (San Antonio, Texas, U.S.) replaced an older in-line precalciner with a new downdraft precalciner to improve production capacity. This was part of a larger project replacing preheaters, installing SOx emission reduction equipment, as well as increasing capacity of a roller mill. The new plant was successfully commissioned in 1999. Fuel consumption at Capitol Cement was reduced to 3.4 GJ/t clinker (116 kgce/t clinker) (Frailey, M.L. and K.R. Happ, 2001. Capitol Cement s Project 2000. Proceedings IEEE 2001 Cement Industry Technical Conference, May 2001). " The Hejiashan Cement Company, Ltd. in Jiangshan City, Zhejiang Province installed two new dry process kilns in 2001 and 2003 at a cost of 105 million RMB for a 1000 tonne per day kiln and 156 million RMB for a 1500 tonne per day kiln, respectively (Institute of Technical Information for Building Materials Industry (ITIBMIC). 2004. Final Report on Cement Survey. Prepared for the United Nations Industrial Development Organization (UNIDO) for the Contract Entitled Cement Sub-sector Survey for the Project Energy Conservation and GHG Emissions Reduction in Chinese TVEs-Phase II. Contract no. 03/032/ML, P.O. No. 16000393, September 9). This equates to roughly 300 RMB/t clinker ($37 U.S./t). Power consumption is expected to be 85.87 kWh/t clinker and fuel consumption 2.5GJ/t clinker (85 kgce/t clinker) for the 1000 tonne per day kiln. " The conversion of a plant in Italy, using the existing rotary kiln, led to a capacity increase of 80 to 100% (from 1100 tpd to 2000 to 2200 tpd), while reducing specific fuel consumption from 3.6 to 3.1-3.2 GJ/t clinker (123 to 106-109 kgce/t clinker), resulting in savings of 11 to 14% (Sauli, R.S. 1993. Rotary Kiln Modernization and Clinker Production Increase at Testi Cement Plant of S.A.C.C.I. Spa., Italy Proc. KHD Symposium '92, 2 Modern Burning Technology, KHD Humboldt Wedag, Cologne, Germany). <sa ! B XPP?-]4!@@!) M5=@@!  <Low Pressure Drop Cyclones for Suspension Preheaters for Clinker Making in Rotary Kilns Description: Cyclones are a basic component of plants with pre-heating systems. The installation of newer cyclones in a plant with lower pressure losses will reduce the power consumption of the kiln exhaust gas fan system. Energy/Environment/Cost/Other Benefits: " Depending on the efficiency of the fan, 0.66 to 0.77 kWh/t clinker can be saved for each 50 mm water column (W.C.) the pressure loss is reduced. For most kilns that are older, this amounts to savings of 0.66 to 1.1 kWh/t clinker (Birch, E. 1990. Energy Savings in Cement Kiln Systems Energy Efficiency in the Cement Industry (Ed. J. Sirchis), London, England: Elsevier Applied Science: 118-128). " Installation of the cyclones can be expensive, since it may often entail the rebuilding or the modification of the preheater tower, and the costs are very site specific. " New cyclone systems may increase overall dust loading and increase dust carryover from the preheater tower. However, if an inline raw mill follows it, the dust carryover problem becomes less of an issue. " A cost of $3/annual tonne clinker is assumed for a low-pressure drop cyclone system. " The best technology available in China is imported from Austria (see below) (Cui, Y., 2004 and 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC)). Case Studies: " Fujimoto (1994) discussed a Lehigh Cement plant retrofit in which low-pressure drop cyclones were installed in their Mason City, Iowa plant and saved 4.4 kWh/t clinker (Birch, E. 1990. Energy Savings in Cement Kiln Systems Energy Efficiency in the Cement Industry (Ed. J. Sirchis), London, England: Elsevier Applied Science: 118-128). " The Satna Cement Works of Birla Corporation Limited in India added vortex finder vanes on the top stage cyclones to reduce pressure in their kilns and found electricity savings of 0.50 kWh/t clinker at a cost of 3 INR/t clinker (0.5 RMB/t clinker). (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175367790.14/view). " The Birla Vikas Cement Works of Birla Corporation Limited in India also added vortex finder vanes on their stage one cyclones of the preheater and precacliner strings to reduce pressure and found electricity savings of 0.62 kWh/t clinker at a cost of 3 INR/t clinker (0.5 RMB/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175367790.14/view). < }2 mhe " B XPP?-Z]4"@,#) A!nHbD1 V$  < Indirect Firing for Clinker Making in Rotary Kilns Description: Historically the most common firing system is the direct-fired system. Coal is dried, pulverized and classified in a continuous system, and fed directly to the kiln. This can lead to high levels of primary air (up to 40% of stoichiometric). These high levels of primary air limit the amount of secondary air introduced to the kiln from the clinker cooler. Primary air percentages vary widely, and non-optimized matching can cause severe operational problems with regard to creating reducing conditions on the kiln wall and clinker, refractory wear and reduced efficiency due to having to run at high excess air levels to ensure effective burnout of the fuel within the kiln. In more modern cement plants, indirect fired systems are most commonly used. In these systems, neither primary air nor coal is fed directly to the kiln. All moisture from coal drying is vented to the atmosphere and the pulverized coal is transported to storage via cyclone or bag filters. Pulverized coal is then densely conveyed to the burner with a small amount of primary transport air (Smart, J. and B. Jenkins. 2000. Combustion in the Rotary Kiln, The Combustion Institute, Leeds, UK. Available at: http://www.chemeng.ucl.ac.uk/research/combustion/nl2000_1/nl00_1_9.html). As the primary air supply is decoupled from the coal mill in multi-channel designs, lower primary air percentages are used, normally between 7 and 12% of stoichiometric air (Bhatty, J. I., F. M. Miller and S. H. Kosmatka (eds.) 2004. Innovations in Portland Cement Manufacturing. Portland Cement Association). The multi-channel arrangement also allows for a degree of flame optimization. This is an important feature if a range of fuels is fired. Input conditions to the multi-channel burner must be optimized to secondary air and kiln aerodynamics for optimum operation (Smart, J. and B. Jenkins. 2000. Combustion in the Rotary Kiln, The Combustion Institute, Leeds, UK. Available at: http://www.chemeng.ucl.ac.uk/research/combustion/nl2000_1/nl00_1_9.html). Energy/Environment/Cost/Other Benefits: " The optimization of the combustion conditions will lead to reduced NOx emissions, better operation with varying fuel mixtures, and reduced energy losses. " Excess air infiltration is estimated to result in heat losses equal to 75 MJ/t (2.6 kgce/t) of clinker. Assuming a reduction of excess air between 20% and 30%, indirect firing may lead to fuel savings of 15 to 22 MJ/t (0.51 to 0.75 kgce/t) of clinker. " The advantages of improved combustion conditions will lead to a longer lifetime of the kiln refractories and reduced NOx emissions. These co-benefits may result in larger cost savings than the energy savings alone. " The disadvantage of an indirect firing system is the additional capital cost. Case Studies: " In 1997, California Portland s plant in Colton, California (U.S.) implemented an indirect firing system for their plant, resulting in NOx emission reductions of 30 to 50%, using a mix of fuels including tires. The investment costs of the indirect firing system were $5 million for an annual production capacity of 680,000 tonnes clinker, or $7.4/t clinker.<!;   # BX XPP?-c]4#@X#) .[-D D<Kiln Combustion System Improvements for Clinker Making in Vertical Shaft Kilns Description: Fuel combustion systems in kilns can be contributors to kiln inefficiencies, often resulting in higher CO formation. Inefficiencies are caused by incomplete combustion of fuel, combustion with excess or inadequate air, uneven air distribution, and oversupply of coal (Venkateswaran, S.R. and H.E. Lowitt. 1988. The U.S. Cement Industry, An Energy Perspective, U.S. Department of Energy, Washington D.C., USA; Liu, F., M. Ross and S. Wang. 1995. Energy Efficiency of China s Cement Industry. Energy 20 (7): 669-681). Inadequate blower capacity and leakage can result in insufficient air supply. Improvement of air distribution requires better quality raw material pellets and precise kiln operation. Sophisticated VSKs are mechanized with automatic feeding and discharging equipment, while older VSKs are still operated manually (Liu, F., M. Ross and S. Wang. 1995. Energy Efficiency of China s Cement Industry. Energy 20 (7): 669-681). Oversupply of coal often results from coal powder that has been overground, supplying high fuel density. At low temperatures and insufficient oxygen, overground coal reacts with CO2 and generates CO. More information on automation of the kiln, feed, and blending can be found in the measure  Energy Management and Process Control Systems , above. In China, domestic technologies are being used for medium and small cement plants; for larger plants, many are using imported technologies (Cui, Y., 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC)). Energy/Environment/Cost/Other Benefits: " Energy savings for rotary kilns are about 2 to 10%. In BEST Cement, we assume these savings apply to vertical shaft kilns as well. < #Da $ B XPP?-iZ]4$@t%)   qL|ʀ  <Replacing Vertical Shaft Kilns with New Suspension Preheater/Precalciner Kilns for Clinker Making in Vertical Shaft Kilns Description: The new suspension preheater (NSP) technique is being developed for 1000 t/day, 2000 t/day and 4000 t/day (Global Environment Institute (GEI). 2005. Financing of Energy Efficiency Improvement for Cement Industry in China. January). NSP should be used for medium- or large-scale cement plants that are being either enlarged or rebuilt. For the small cement plants, earthen vertical kiln (and hollow rotary kiln with dry method) should be gradually abandoned. Further description of these kilns is made above. Energy/Environment/Cost/Other Benefits: " Some  key Chinese plants ( Key Chinese plants generally refer to large, centrally administered state-owned enterprises (Sinton, J.E., 1996. Energy Efficiency in Chinese Industry: Positive and Negative Influences of Economic System Reforms. PhD Thesis, University of California- Berkeley)) use 5.4 GJ/t clinker (184 kgce/t clinker), while advanced precalciner kilns use about 3 GJ/t clinker (102 kgce/t clinker); a savings of 2.4 G/t clinker (82 kgce/t clinker) ( Liu, F., M. Ross and S. Wang. 1995. Energy Efficiency of China s Cement Industry. Energy 20 (7): 669-681). " By the end of 2004, China put into service 140 new suspension preheater/precalciner (NSP) and suspension preheater (SP) kilns; of those, 50 were new in 2004 (Cui, Y., 2004 and 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC)). " For more information on this technology, also see measures in Energy Efficiency Opportunities for Clinker Production  Rotary Kilns Section. Block Diagram or Photo: Sample images from Chinese cement plants having rotary kilns with preheaters and precalciners. Case Studies: " The Liulihe Cement Factory installed a precalciner kiln with a 5-stage preheater and a preburning furnace and found fuel consumption to be 3.011 G/t (246.6 kgce/t) (Institute of Technical Information for Building Materials Industry (ITIBMIC). 2004. Final Report on Cement Survey. Prepared for the United Nations Industrial Development Organization (UNIDO) for the Contract Entitled Cement Sub-sector Survey for the Project Energy Conservation and GHG Emissions Reduction in Chinese TVEs-Phase II. Contract no. 03/032/ML, P.O. No. 16000393, September 9). <- a % B  XPP? @]4%@ %) `*BoH.G x< Process Control and Management in Grinding Mills for Finish Grinding Description: Control systems for grinding operations are developed using the same approaches as for kilns (see kiln energy efficiency measures for more information). The systems control the flow in the mill and classifiers, attaining a stable and high quality product. Several systems are marketed by a number of manufacturers. Expert systems have been commercially available since the early 1990 s. Energy/Environment/Cost/Other Benefits: " Energy savings of 3 to 3.5 kWh/t (reduction in power consumption by 2%-3%) " Payback periods are typically between 6 months and 2 years (Martin, G. and S. McGarel. 2001a. Automation Using Model Predictive Control in the Cement Industry. Pavillion Technologies, Inc., Austin, TX (based on a paper published in International Cement Review, February: 66-67). Available at: http://www.pavtech.com/. Albert, O., 1993. MCE  An Expert System for Mill Plant Control, Krupp Polysius, Germany). " Reduced process and quality variability " Improved throughput/production increases Case Studies: " Use of Rockwell Automation s Mill Optimizer for optimizing closed circuit raw meal and finish grinding circuits in a major cement company s Asia Pacific plant resulting in reduction of specific power consumption by 3% through improved throughput and closer control of fan/motor loads as well as improved product quality control (Rockwell Automation, 2004. Online Control at Major Cement Company in Asia Pacific Maximizes Throughput, Lowers Product Quality Variation to 30% and Reduces Specific Energy Consumption by 3%. Pub No ELPPVP-AP-009A-EN-D). " At the Roanoke Cement Company in Virginia, the Pavilion advanced process control system was install on two finish mills, resulting in a 3 to 3.5 decrease in kWh/t energy use and a production increase of 3 to 4 tons per hour (Pavilion Technologies.  Easy as APC ). " Use of a Pavilion advanced process control system at the Cemex Fairborn plant resulted in 40% process variability reduction, 30% quality variability reduction, 2% production increase, 2% energy consumption decrease (Lauer, D, Becerra, K., Deng, D.J, 2005.  Maximizing Mill Throughput, International Cement Review). " At the Golden Bay Cement plant in New Zealand, a Pavilion advanced process control system for the finish mill led to a 3% increase in throughput, 50% reduction in residue variation, and a return on the investment of less than one year (Spear, M., 2004.  Cementing Success, Process Engineering, pp 27-28). " The Karlstadt plant of Schwenk KG (Germany) implemented an expert system in a finishing mill in 1992, increasing mill throughput and saving energy. The payback is estimated between 1.5 and 2 years in Germany (Albert, O., 1993. MCE  An Expert System for Mill Plant Control, Krupp Polysius, Germany). " Magotteaux (Belgium) has marketed a control system for mills since 1998 and has sold six units to plants in Germany (Rohrdorfer Zement), Greece (Heracles General Cement), South Africa (PPC Group) and the United Kingdom (UK) (Rugby Group). " Experience with a cement mill at the South Ferriby plant of the Rugby Group in the UK showed increased production (+3.3%) and power savings equal to 3%, while the standard deviation in fineness went down as well (Van den Broeck, M., 1999. GO Control Goes  Multi-Circuit International Cement Journal 1, pp.35-37). " Krupp Polysius markets the PolExpert system and reports energy savings between 2.5 and 10% (typically 8%), with increased product quality (lower deviation) and production increases of 2.5  10%, after installing control systems in finishing mills (Goebel, Alexander, 2001. Personal communication with Alexander Goebel, Krupp Polysius, Beckum, Germany, December 20th, 2001). " Similar results have been achieved with model predictive control (using neural networks) for a cement ball mill at a South-African cement plant (Martin, G. and S. McGarel. 2001a. Automation Using Model Predictive Control in the Cement Industry. Pavillion Technologies, Inc., Austin, TX (based on a paper published in I<nternational Cement Review, February: 66-67). Available at: http://www.pavtech.com/). " Pavilion Technologies (US) has developed a new control system using neural networks. Pavilion Technologies reports a 4-6% throughput increase (and corresponding reduction in specific power consumption) for installing a model predictive control system in finish ball mill (Martin, G., S. McGarel, T. Evans, and G. Eklund. 2001. Reduce Specific Energy Requirements while Optimizing NOx Emissions Decisions in Cement with Model Predictive Control, Personal Communication from Pavilion Technologies, Inc., Austin, TX, December 3). <hYxa & B XPP?-]4&@') rJ^eI <Vertical Roller Mill for Finish Grinding Description: Roller mills employ a mix of compression and shearing, using 2-4 grinding rollers carried on hinged arms riding on a horizontal grinding table (Cembureau, 1997b. Best Available Techniques for the Cement Industry, Brussels: Cembureau; Alsop, P.A. and J.W. Post. 1995. The Cement Plant Operations Handbook, (First edition), Tradeship Publications Ltd., Dorking, UK). The raw material is ground on a surface by rollers that are pressed down using spring or hydraulic pressure, with hot gas used for drying during the grinding process (Bhatty, J. I., F. M. Miller and S. H. Kosmatka (eds.), 2004. Innovations in Portland Cement Manufacturing. Skokie, IL: PCA). Energy/Environment/Cost/Other Benefits: " Energy use of between 18.3 and 20.3 kWh/t clinker (compared to 30-42 kWh/t clinker for a ball mill depending on the fineness of the cement.) " Can accept raw materials with up to 20% moisture content. " Less variability in product consistency. Case Studies: " A vertical roller mill in the U.S. uses about 18.3 kWh/t clinker compared to 35.2 kWh/t clinker for a ball mill, saving 16.9 kWh/t clinker (Simmons, M., Gorby, L., and Terembula, J., 2005.  Operational Experience from the United States First Vertical Roller Mill for Cement Grinding, IEEE). " A vertical roller mill with four grinding rollers and a high-efficiency separator at the Bosenberg cement plant in Germany has a specific power consumption of 11.45 kWh/t raw meal (20.3 kWh/t clinker) (Schneider, U., "From ordering to operation of the first quadropol roller mill at the Bosenberg Cement Works," ZKG International, No.8, 1999: 460-466). " A ball mill was replaced with a vertical mill for finish grinding at the Ramla Cement Plant in Israel. They found savings of 10 kWh/t cement and a lifetime for the equipment of 20 years (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/DNV-CUK1160716504.46/view). <($ ' B臖 XPP?-i]4'@臖() NP?qJ74  <High Pressure (Hydraulic) Roller Press for Finish Grinding Description: A high pressure roller press, in which two rollers pressurize the material up to 3,500 bar, can replace ball mills for finish grinding, improving the grinding efficiency dramatically (Seebach, H.M. von, E. Neumann and L. Lohnherr, 1996. State-of-the-Art of Energy-Efficient Grinding Systems ZKG International 2 49 pp.61-67). Energy/Environment/Cost/Other Benefits: " A roller press with a V-separator uses 15.6 kWh/t clinker for finish grinding (Bhatty, J. I., F. M. Miller and S. H. Kosmatka (eds.), 2004. Innovations in Portland Cement Manufacturing. Skokie, IL: PCA). " Capital cost estimates for installing a new roller press vary widely in the literature, ranging from low estimates of $2.5/annual tonne cement capacity (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada) or $3.6/annual tonne cement capacity (Kreisberg, A., 1993. Selection and Application of Roller Press for Raw Meal Preparation at Alpena, Proc. KHD Symposium '92, Volume 1, Modern Roller Press Technology, KHD Humboldt Wedag, Cologne, Germany) to high estimates of $8/annual tonne cement capacity (COWIconsult, March Consulting Group and MAIN. 1993. Energy Technology in the Cement Industrial Sector, Report prepared for CEC - DG-XVII, Brussels, April 1992). " The capital costs of roller press systems are lower than those for other systems (Kreisberg, A., 1993. Selection and Application of Roller Press for Raw Meal Preparation at Alpena, Proc. KHD Symposium '92, Volume 1, Modern Roller Press Technology, KHD Humboldt Wedag, Cologne, Germany) or at least comparable (Patzelt, N., 1993. Finish Grinding of Slag, World Cement 10 24 pp.51-58). " Can achieve an increase in throughput of about 20% and energy savings of about 7 to 15% (Bhatty, J. I., F. M. Miller and S. H. Kosmatka (eds.), 2004. Innovations in Portland Cement Manufacturing. Skokie, IL: PCA). Case Studies: " Installation of a high pressure roller press at Coplay Cement s Nazareth I Plant increased production by 70 short tons per hour. The high pressure roller press resulted in energy savings of 30% or 15 kWh per short ton, reducing total plant power costs, resulting in savings of over $500,000 per year (Conroy, G.H.,  Experience of the High Pressure Roller Press Installation at CoplyCement s Nazareth I Plant, Cement Industry Technical Conference, 1989. XXXI). <>: . a ( BL XPP?<-A-]4(@L*) (7Ip0E>  <Horizontal Roller Mill for Finish Grinding Description: In the Horomill, first demonstrated in Italy in 1993 (Buzzi, S. 1997. Die Horomill - Eine Neue Mhle fr die Feinzerkleinerung, ZKG International 3 50: 127-138), a horizontal roller within a cylinder is driven. The centrifugal forces resulting from the movement of the cylinder cause a uniformly distributed layer to be carried on the inside of the cylinder. The layer passes the roller (with a pressure of 700-1000 bar) (Marchal, G. 1997. Industrial Experience with Clinker Grinding in the Horomill Proc.1997 IEEE/PCA Cement Industry Technical Conference XXXIX Conference Record, Institute of Electrical and Electronics Engineers: New Jersey). The finished product is collected in a dust filter. Energy/Environment/Cost/Other Benefits: " Compared with ball mills, Horomills offer energy savings of 35% to 40% for cement and up to 50% for raw materials (Bhatty, J. I., F. M. Miller and S. H. Kosmatka (eds.), 2004. Innovations in Portland Cement Manufacturing. Skokie, IL: PCA). " Vendor information provides the following energy use values (fcb.ciment. The New Generation of Horomill Gets the Benefit of Mechanical Optimization. http://www.fcb-ciment.com/en/cement/horomill_0.asp): --Ordinary Portland cement: ball mill 30 kWh/t, Horomill 19.5 kWh/t --Pozzolanic or limestone cement: ball mill 30 kWh/t, Horomill 16.5 kWh/t --Cement raw meal: ball mill 14 kWh/t, Horomill 7 kWh/t " The Horomill is a compact mill that can produce a finished product in one step and hence has relatively low capital costs. " Some new mill concepts may lead to a reduction in operation costs of as much as 30-40% (Sutoh, K., M. Murata, S. Hashimoto, I. Hashimoto, S. Sawamura and H. Ueda, 1992. Gegenwrtiger Stand der Vormahlung von Klinker und Zement-rohmaterialien nach dem CKP-System, ZKG 1 45 pp.21-25). Case Studies: " After the first demonstration of the Horomill in Italy, this concept is now also applied in plants in Mexico (Buzzi, S. 1997. Die Horomill - Eine Neue Mhle fr die Feinzerkleinerung, ZKG International 3 50: 127-138), Germany, Czech Republic and Turkey (Duplouy, A. and J. Trautwein. 1997. Umbau und Optimierung der Drehofenanlagen im Werk Karsdorf der Lafarge Zement Gmbh. ZKG International 4 50: 190-197). " Cement grinding using a Horomill in a Turkish cement plant consumed 20.07 kWh/t (Bhatty, J. I., F. M. Miller and S. H. Kosmatka (eds.), 2004. Innovations in Portland Cement Manufacturing. Skokie, IL: PCA). <*- a ) B XPP?<=-]4)@`*) tju: IWD' p<Improved grinding media (for ball mills) Description: Improved wear resistant materials can be installed for grinding media, especially in ball mills. Grinding media are usually selected according to the wear characteristics of the material. Increases in the ball charge distribution and surface hardness of grinding media and wear resistant mill linings have shown a potential for reducing wear as well as energy consumption (Venkateswaran, S.R. and H.E. Lowitt. (1988). "The U.S. Cement Industry, An Energy Perspective", U.S. Department of Energy, Washington D.C., USA). Improved balls and liners made of high chromium steel is one such material but other materials are also possible. Other improvements include the use of improved liner designs, such as grooved classifying liners. Energy/Environment/Cost/Other Benefits: " Improved grinding media have the potential to reduce grinding energy use by 5-10% in some mills, which is equivalent to estimated savings of 3-5 kWh/t cement (Venkateswaran, S.R. and H.E. Lowitt. (1988). "The U.S. Cement Industry, An Energy Perspective", U.S. Department of Energy, Washington D.C., USA). < [pmts * B XPP?<E]4*@L,) _2dL  <High Efficiency Classifiers for Finish Grinding Description: A recent development in efficient grinding technologies is the use of high-efficiency classifiers or separators. Classifiers separate the finely ground particles from the coarse particles. The large particles are then recycled back to the mill. Standard classifiers may have a low separation efficiency, which leads to the recycling of fine particles, resulting in extra power use in the grinding mill. In high-efficiency classifiers, the material is more cleanly separated, thus reducing over-grinding. High efficiency classifiers or separators have had the greatest impact on improved product quality and reducing electricity consumption. Newer designs of high-efficiency separators aim to improve the separation efficiency further and reduce the required volume of air (hence reducing power use), while optimizing the design. Energy/Environment/Cost/Other Benefits: " A study of the use of high efficiency classifiers in Great Britain found a reduction in electricity use of 7 kWh/t cement after the installation of the classifiers in their finishing mills and a 25% production increase (Parkes, F.F., 1990. Energy Saving by Utilisation of High Efficiency Classifier for Grinding and Cooling of Cement on Two Mills at Castle Cement (Ribblesdale) Limited, Clitheroe, Lancashire, UK, Energy Efficiency in the Cement Industry (Ed. J. Sirchis), London, England: Elsevier Applied Science). " One study estimates a reduction of 8% of electricity use (6 kWh/t cement) (Holderbank Consulting. (1993).  Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada) while other studies estimate 1.9-2.5 kWh/t cement (Efficiency Classifier Proc. 35th IEEE Cement Industry Technical Conference, Toronto, Ontario, Canada, May 1993; Sssegger, A., 1993. Separator-Report '92 Proc. KHD Symposium '92, Volume 1 Modern Roller Press Technology, KHD Humboldt Wedag, Cologne, Germany). " Actual savings will vary by plant and cement type and fineness required. Case Studies: " The electricity savings from installing a new high-efficiency classifier at a cement plant in Origny-Rochefort (France) varied between 0 and 6 kWh/t (Van den Broeck, M., 1998. A SD100 Sturtevant High-Efficiency Classifier for Origny-Rochefort, International Cement Journal 2 pp.39-45), and investment costs were $2/annual tonne finished material (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada). " The Satna Cement Works of Birla Corporation Limited in India optimized the design of their classifier and found energy savings of 1.62 kWh/t clinker at a cost of 7.8 INR/t clinker (1.3 RMB/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175367790.14/view). <K7 a + Bx XPP?9n]4+@x,) /%RH 1< V <Changing Product and Feedstock: Low-Alkali Cement Description: In North America, the cement industry produces cements with a low alkali content (probably around 20 to 50% of the market), a much higher share than found in many other countries (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada). In some areas in the U.S. as well as China, aggregate quality may be such that low-alkali cements are required by the cement company s customers or by the climate in a particular region (for example, alkali cements are more suitable the south of China in areas of higher rainfall than in drought areas in the North). Reducing the alkali content is achieved by venting (called the by-pass) hot gases and particulates from the plant, loaded with alkali metals. The by-pass also avoids plugging in the preheaters. This becomes cement kiln dust (CKD). Disposal of CKD is regulated under the Resource Conservation and Recovery Act (RCRA). Many customers demand a lower alkali content, as it allows greater freedom in the choice of aggregates. The use of fly-ash or blast-furnace slags as aggregates (or in the production of blended cement, see below) may reduce the need for low-alkali cement. Low alkali cement is produced using domestic technology in China (Cui, Y., 2004 and 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC)). Energy/Environment/Cost/Other Benefits: " Low alkali cement production leads to lower energy consumption. Savings of 8 to 21 MJ/t (0.3 to 0.72 kgce/t) per percent bypass are assumed (Alsop, P.A. and J.W. Post. 1995. The Cement Plant Operations Handbook, (First edition), Tradeship Publications Ltd., Dorking, UK). The lower figure is for precalciner kilns, while the higher figure is for preheater kilns. " Typically, the bypass takes 10 to 70% of the kiln exhaust gases (Alsop, P.A. and J.W. Post. 1995. The Cement Plant Operations Handbook, (First edition), Tradeship Publications Ltd., Dorking, UK). " Additionally, electricity is saved due to the increased cement production, as the CKD would otherwise end up as clinker and not cement, requiring further processing. " For illustrative purposes, assume a 20% point reduction in bypass volume, resulting in energy savings of 0.19 to 0.5 GJ/t clinker (6.5 to 17 kgce/t clinker). " There are no investments involved in this product change, although cement users (for example ready-mix producers) may need to change the type of aggregates used (which may result in costs). Hence, this measure is most successfully implemented in coordination with ready-mix producers and other large cement users. Vendor Contact information: Implement this measure in coordination with ready-mix producers or other large cement users. <6V a , B܉ XPP?4]4,@܉.) odNv. < Changing Product and Feedstock: Blended Cements Description: The production of blended cements involves the intergrinding of clinker with one or more additives (fly ash, pozzolans, blast furnace slag, volcanic ash) in various proportions. Blended cements demonstrate a higher long-term strength, as well as improved resistance to acids and sulfates, while using waste materials for high-value applications. Short-term strength (measured after less than 7 days) of blended cement may be lower, although cement containing less than 30% additives will generally have setting times comparable to concrete based on Portland cement. Blended cement has been used for many decades around the world. Blended cements are very common in Europe; blast furnace and pozzolanic cements account for about 12% of total cement production with Portland composite cement accounting for an additional 44% (Cembureau, 1997b. Best Available Techniques for the Cement Industry, Brussels: Cembureau). Blended cements were introduced in the U.S. to reduce production costs for cement (especially energy costs), to expand capacity without extensive capital costs, to reduce emissions from the kiln. However, in the U.S., the consumption and production of blended cement is still limited. However, Portland ordinary cement and Portland slag cement are used widely in cement produced in China. In addition, due to technical advancement and market development allowing the production of different kinds and grades of cement, some industrial byproducts like blast furnace slag, fly ash, coal gangue, limestone, zeolite, pozzolana as well as natural minerals are widely used in cement production. The average percentage of admixtures in Chinese cement products stands at 24% to 26% (Institute of Technical Information for Building Materials Industry (ITIBMIC). 2005. A Survey on the Chinese Market of Cement Admixtures for Holcim Company). China produces 25 Mt of blast furnace slag per year and has a long history of using this type of waste. Where utilized, about 20 to 25% of clinker is replaced; the country s highest slag ratio is 50%. In addition, blast furnace slag is added into concrete as well as clinker. Fly ash is also increasingly being used in China (Cui, Y., 2004 and 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC)). Energy/Environment/Cost/Other Benefits: " Prices for different additives vary greatly. Prices change with location, output, market need, produce type and ways of handling. Fuel savings of at least 10% is estimated with a similar increase in production (Institute of Technical Information for Building Materials Industry (ITIBMIC). 2005. A Survey on the Chinese Market of Cement Admixtures for Holcim Company). " The use of blended cements is a particularly attractive efficiency option since the intergrinding of clinker with other additives not only allows for a reduction in the energy used (and carbon emissions) in clinker production, but also corresponds to a reduction in carbon dioxide emissions in calcination as well. " For blended cement with, on average, a clinker/cement ratio of 65%, the reduction in clinker production corresponds to a specific fuel savings of 1.42 GJ/t cement (48.5 kgce/t cement). There is an increase in fuel use of 0.09 GJ/t cement (3.1 kgce/t cement) for drying of the blast furnace slags but a corresponding energy savings of 0.2 GJ/t cement (7 kgce/t cement) for reducing the need to use energy to bypass kiln exit gases to remove alkali-rich dust. Energy savings are estimated to be 9 to 23 MJ/t cement (0.3 to 7.1 kgce/t cement) per percent bypass (Alsop, P.A. and J.W. Post. 1995. The Cement Plant Operations Handbook, (First edition), Tradeship Publications Ltd., Dorking, UK). The bypass savings are due to the fact that blended cements offer an additional advantage in that the inter-ground materials also lower alkali-silica reactivity (ASR), thereby allowing a reduction in energy consumption needed to remove the high alkali content kiln dusts. In pr<actice, bypass savings may be minimal to avoid plugging of the preheaters, requiring a minimum amount of bypass volume. This measure therefore results in total fuel savings of 1.4 GJ/t blended cement (48 kgce/t blended cement) (0.9 GJ/t clinker or 31 kgce/t clinker for 0.65 clinker to cement ratio). However, electricity consumption is expected to increase, due to the added electricity consumption associated with grinding blast furnace slag (as other materials are more or less fine enough). " The costs of applying additives in cement production may vary. Capital costs are limited to extra storage capacity for the additives. However, blast furnace slag may need to be dried before use in cement production. This can be done in the grinding mill, using exhaust from the kiln, or supplemental firing, either from a gas turbine used to generate power or a supplemental air heater. The operational cost savings will depend on the purchase (including transport) costs of the additives (To avoid disclosing proprietary data, the USGS does not report separate value of shipments data for  cement-quality fly ash or granulated blast furnace slag, making it impossible to estimate an average cost of the additives), the increased electricity costs for (finer) grinding, the reduced fuel costs for clinker production and electricity costs for raw material grinding and kiln drives, as well as the reduced handling and mining costs. These costs will vary by location, and would need to be assessed on the basis of individual plants. An increase in electricity consumption of 16.5 kWh/t cement (11 kWh/t clinker) (Buzzi, S. 1997. Die Horomill - Eine Neue Mhle fr die Feinzerkleinerung, ZKG International 3 50: 127-138) is estimated while an investment cost of $0.72/t cement capacity ($0.5/t clinker), which reflects the cost of new delivery and storage capacity (bin and weigh-feeder) is assumed. Case Studies: " The Lianzhuo cement Factory in Guangdong Province, China, replaced some of its high grade limestone with 33 to 34% calcium oxide (CaO), along with copper tailing high content iron sulfide from a nearby county. They found fuel savings of 2.6 to 3.4 GJ/t clinker (89 to 120 kgce/t clinker), a coal savings of over 50%. The clinker production has increased from 2 tonne/day to 14 tonne/day, its strength has improved and its quality is stable (Institute of Technical Information for Building Materials Industry (ITIBMIC). 2004. Final Report on Cement Survey. Prepared for the United Nations Industrial Development Organization (UNIDO) for the Contract Entitled Cement Sub-sector Survey for the Project Energy Conservation and GHG Emissions Reduction in Chinese TVEs-Phase II. Contract no. 03/032/ML, P.O. No. 16000393, September 9). Vendor Contact Information: Blast furnace slags will be obtained from iron and steel plants; fly ash from coal burning electricity generation plants. Other materials will be dependent on local availability where the rock or mineral is being mined (like limestone powder, pozzalans) or the waste is being generated (like sewage sludge). < 0 - B@ XPP?x1]4-@@.) qD[D"5m < Changing Product and Feedstock: Use of Waste-Derived Fuels Description: Waste fuels can be substituted for traditional commercial fuels in the kiln. In North America, many of the alternative fuels are focused on the use of tires or tire-derived fuel. Since 1990 more than 30 cement plants have gained approval to use tire-derived fuels, burning around 35 million tires per year (Cement Kiln Recycling Coalition (CKRC). 2002. Volume of Hazardous Wastes Used as Fuel in Cement Kilns Washington, D.C. Available at: http://www.ckrc.org/infocen.html). Other plants have experience injecting solid and fluid wastes, as well as ground plastic wastes. Tires accounted for almost 5% of total fuel inputs in the U.S. cement industry in 1999 and all wastes total about 17% of all fuel inputs. The trend towards increased waste use will likely increase after successful tests with different wastes in Europe and North America. New waste streams include carpet and plastic wastes, filter cake, paint residue and (dewatered) sewage sludge (Hendriks, C.A., E. Worrell, L. Price, N. Martin and L. Ozawa Meida. 1999. The Reduction of Greenhouse Gas Emissions from the Cement Industry, IEA Greenhouse Gas R&D Programme, Cheltenham, United Kingdom (Report PH3/7), May). Cement kilns also burn hazardous wastes; since the early 1990 s cement kilns burn annually almost 1 Mt of hazardous waste (Cement Kiln Recycling Coalition (CKRC). 2002. Volume of Hazardous Wastes Used as Fuel in Cement Kilns Washington, D.C. Available at: http://www.ckrc.org/infocen.html). A cement kiln is an efficient way to recover energy from waste. The carbon dioxide emission reduction depends on the carbon content of the waste-derived fuel, as well as the alternative use of the waste and efficiency of use (for example incineration with or without heat recovery). The high temperatures and long residence times in the kiln destroy virtually all organic compounds, while efficient dust filters may reduce some other potential emissions to safe levels (Hendriks, C.A., E. Worrell, L. Price, N. Martin and L. Ozawa Meida. 1999. The Reduction of Greenhouse Gas Emissions from the Cement Industry, IEA Greenhouse Gas R&D Programme, Cheltenham, United Kingdom (Report PH3/7), May; Cembureau, 1997b. Best Available Techniques for the Cement Industry, Brussels: Cembureau). Currently, in China only three cement plants are burning waste fuels. Beijing Cement Plant has the capacity to dispose of 10 kt per year of 25 types of waste; the plant is burning solid waste from the chemical industry, some paints, solvents and waste sludge from water treatment (Cui, Y., 2004 and 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC); Wang, Xuemin, 2006a. Personal communication with Prof. Wang Xuemin of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC). February). Shanghai Jinshan Cement Plant disposes of sludge dredged from the Huangpu River which runs through Shanghai (Cui, Y., 2004 and 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC)). Hong Kong Cement Plant purchases waste from other provinces to utilize in its kilns (Wang, Xuemin, 2006. Personal communication with Prof. Wang Xuemin of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC). February). Other plants are utilizing wastes but the amounts are very small (Wang, Xuemin, 2006. Personal communication with Prof. Wang Xuemin of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC). February). Energy/Environment/Cost/Other Benefits: " The revenues from waste intake have helped to reduce the production costs of all waste-burning cement kilns, and especially of wet process kilns. " Waste-derived fuels may replace the use of commercial fuels, and may result in net energy savings and reduced CO2 emissions, depending on the alternative use of the wastes (for example. i<9ncineration with or without energy recovery). " A net reduction in operating costs by injecting solid and fluid wastes, as well as ground plastic wastes is assumed (Centre for the Analysis and Dissemination of Demonstrated Energy Technologies (CADDET), International Energy Agency. 1996. Tyres used as fuel in cement factory, Sittard, the Netherlands: CADDET. Gomes, A. S. 1990. Energy Saving and Environmental Impact in the Cement Industry, Energy Efficiency in the Cement Industry (Ed. J. Sirchis), London, England: Elsevier Applied Science: 23-26. Venkateswaran, S.R. and H.E. Lowitt. 1988. The U.S. Cement Industry, An Energy Perspective, U.S. Department of Energy, Washington D.C., USA). " Investment costs are estimated to be $1.1/annual tonne clinker for a storage facility for the waste-derived fuels and retrofit of the burner (if needed). Case Studies: " The St. Lawrence Cement Factory in Joliette, Quebec, Canada completed a project in 1994 where they installed an automated tire feed system to feed whole tires into the mid-section of the kiln, which replaced about 20% of the energy (Centre for the Analysis and Dissemination of Demonstrated Energy Technologies (CADDET), International Energy Agency. 1996. Tyres used as fuel in cement factory, Sittard, the Netherlands: CADDET). This translates to energy savings of 0.6 GJ/t clinker (20 kgce/t clinker). Costs for the installation of the Joliette system ran about $3.70/annual tonne clinker capacity. Costs for less complex systems where the tires are fed as input fuel are $0.11 to $1.1/annual tonne clinker. Vendor Contact information: Obtaining waste depends on the waste used; for example, sewage sludge from local waste water treatment plants while paints or solvents come from local chemical plants. The type of waste will also determine the type of additional equipment that is required for burning  drying equipment or additional emissions controls might be needed. <r,em . B XPP?]4.@0) -hdfnFf#.X <1Changing Product and Feedstock: Limestone Portland Cement Description: Similar to blended cement, ground limestone is interground with clinker to produce cement, reducing the needs for clinker-making and calcination. Energy/Environment/Cost/Other Benefits: " This measure reduces energy use in the kiln and clinker grinding as well as CO2 emissions from calcination and energy use. " The addition of up to 5% limestone has shown to have no negative impacts on the performance of Portland cement, while optimized limestone cement would improve the workability slightly (Detwiler, R.J. and P.D. Tennis. 1996. The Use of Limestone in Portland Cement: a State-of-the-Art Review, Skokie, IL: Portland Cement Association). " Adding 5% limestone would reduce fuel consumption by 5% (or on average 0.35 GJ/t clinker or 12 kgce/t clinker), power consumption for grinding by 3.3 kWh/t cement, and CO2 emissions by almost 5%. " Additional costs would be minimal, limited to material storage and distribution, while reducing kiln operation costs by 5%. <a / B XPP?K)]4/@81) 2>Gՙ# j<Changing Product and Feedstock: Use of Steel Slag in Kiln Description: Texas Industries (Midlothian, Texas, U.S.) in 1994 developed a system to use electric arc furnace (EAF) slags of the steel industry as input in the kiln, reducing the use of limestone. The slag that contains tricalcium silicate (C3S) can more easily be converted to free lime than limestone. The slags replace limestone (approximately 1.6 times the weight in limestone). EAFs produce between 0.055 and 0.21 tonnes of slag per tonne of steel (on average 0.12 tonnes/tonne) (United States Department of Energy, Office of Industrial Technologies (U.S.DOE OIT). 1996. Energy and Environmental Profile of the U.S. Iron and Steel Industry, Washington, DC: U.S.DOE OIT). China does not produce this technology domestically, and to date the measure has not been implemented in cement kilns in China (Cui, Y., 2004 and 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC)), however, the measure is mature internationally. Energy/Environment/Cost/Other Benefits: " The CemStar process allows replacing 10 to 15% of the clinker by EAF-slags, reducing energy needs for calcination. The advantage of the CemStar process is the lack of grinding the slags, but adding them to the kiln in 5 cm lumps. Depending on the location of injection it may also save heating energy. " Calcination energy is estimated to be 1.9 GJ/t clinker (65 kgce/t clinker) (Worrell, E., L. Price, N. Martin, C. Hendriks and L. Ozawa Meida. 2001. Carbon Dioxide Emissions from the Global Cement Industry, Annual Review of Energy and the Environment 26: 303-329). " Because the lime in the slag is already calcined, it also reduces CO2 emissions from calcination, while the reduced combustion energy and lower flame temperatures lead to reduced NOx emissions (Battye, R., S. Walsh, J. Lee-Greco. 2000. NOx Control Technologies for the Cement Industry, Prepared for U.S. Environmental Protection Agency, Triangle Park, NC). " For illustrative purposes alone, using a 10% injection of slags would reduce energy consumption by 0.19 GJ/t clinker (6.5 kgce/t clinker), while reducing CO2 emissions by roughly 11%. " Energy savings can be higher in wet kilns due to the reduced evaporation needs. Reductions in NOx emissions vary by kiln type and may be between 9 and 60%, based on measurements at two kilns (Battye, R., S. Walsh, J. Lee-Greco. 2000. NOx Control Technologies for the Cement Industry, Prepared for U.S. Environmental Protection Agency, Triangle Park, NC). " Equipment costs are mainly for material handling and vary between $200,000 and $500,000 per installation. " Total investments are approximately double the equipment costs. " Texas Industries charges a royalty fee for use of CemStar (Battye, R., S. Walsh, J. Lee-Greco. 2000. NOx Control Technologies for the Cement Industry, Prepared for U.S. Environmental Protection Agency, Triangle Park, NC). " Costs savings consist of increased income from additional clinker produced without increased operation and energy costs, as well as reduced iron ore purchases (as the slag provides part of the iron needs in the clinker). The iron content needs to be balanced with other iron sources such as tires and iron ore. " In the U.S., the U.S. Environmental Protection Agency awarded the CemStar process special recognition in 1999 as part of the ClimateWise program. Vendor Contact information: Texas Industries (TXI) Corporate Offices 1341 West Mockingbird Lane Dallas, Texas 75247, U.S. Tel. 972-647-6700 dperkins@txi.com (Particular contact for CemStar) http://www.cemstar.com/ <Ej 0 Bl XPP? $<]40@l$3) C׌;g  <High-Efficiency Fans Description: Fans are used throughout the cement plant in the preheater, the cooler, the alkali bypass. Replacing old inefficient fans with high efficiency fans will decrease power requirements and increase efficiency. Energy/Environment/Cost/Other Benefits: " See case studies below for information on energy savings and costs. " We assume an average savings of 0.4 kWh/t and a cost of 0.07 RMB/t. Case Studies: " Birla Cement Works, Chittorgarh Company in India replaced the vent fan on one cement mill and found a power savings of 0.13 kWh/t clinker at a cost of 0.4 INR/t clinker (0.07 RMB/ t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175367790.14/view). " Satna Cement Works, Birla Corporation Limited, in India, replaced their primary air fan with a high efficiency fan along with an inverter drive panel for speed control of the fan and found power savings of 0.11 kWh/t clinker at a cost of 0.26 INR/t clinker (0.045 RMB/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175367790.14/view). " Birla Vikas Cement Works replaced vent and primary air fans with high efficiency fans with variable voltage variable frequency (VVVF) AC drives for speed control and found savings of 0.65 kWh/t clinker at a cost of 3.1 INR/t clinker (0.53 RMB/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175367790.14/view). " Birla Vikas Cement Works also replaced three other fans with energy efficient fans and VVVF AC drives and found energy savings of 1.34 kWh/t clinker at a cost of 4.2 INR/t clinker (0.73 RMB/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175367790.14/view). " Birla Vikas Cement Works replaced the preheater fan with a more efficient fan for energy savings of 0.70 kWh/t clinker at a cost of 3 INR/t clinker (0.5 RMB/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175367790.14/view). " Birla Vikas Cement Works replaced a less efficient raw mill vent fan and circulating fan with high efficiency fans with VVVF AC drive inverters and found savings of 0.36 kWh/t clinker at a cost of 1.4 INR/t clinker (0.25 RMB/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175367790.14/view). <4  1 BЋ XPP? k]41@Ћ3) &ڹICYP X<High-Efficiency Motors and Drives Description: Motors and drives are used throughout the cement plant to move fans (preheater, cooler, alkali bypass), to rotate the kiln, to transport materials and, most importantly, for grinding. In a typical cement plant, 500-700 electric motors may be used, varying from a few kW to MW-size (Vleuten, F.P. van der. 1994. Cement in Development: Energy and Environment Netherlands Energy Research Foundation, Petten, The Netherlands). Power use in the kiln (excluding grinding) is roughly estimated to be 40-50 kWh/tonne clinker (Heijningen, R.J.J., J.F.M. Castro, and E. Worrell (eds.), 1992. Energiekentallen in Relatie tot Preventie en Hergebruik van Afvalstromen, NOVEM/RIVM, Utrecht/Bilthoven, The Netherlands). Variable speed drives, improved control strategies and high-efficiency motors can help to reduce power use in cement kilns. If the replacement does not influence the process operation, motors may be replaced at any time. However, motors are often rewired rather than being replaced by new motors. Energy/Environment/Cost/Other Benefits: " Power savings may vary considerably on a plant-by-plant basis, ranging from 3 to 8% (Fujimoto, S., 1994. Modern Technology Impact on Power Usage in Cement Plants, IEEE Transactions on Industry Applications, Vol. 30, No. 3, June. Vleuten, F.P. van der. 1994. Cement in Development: Energy and Environment Netherlands Energy Research Foundation, Petten, The Netherlands). " Based on an analysis of motors in the U.S. Department of Energy s MotorMaster+ software, and a breakdown of motors in a 5,000 tpd cement plant given in Bsche (1993), it is assumed that high-efficiency motors replace existing motors in all plant fan systems with an average cost of $0.22/annual tonne cement capacity (Bsche, A., 1993.  Variable Speed Drives in Cement Plants, World Cement 6 24 pp.2-6 (1993). <#X 2 B4 XPP? F]42@4l5) "ePE:2 < Adjustable or Variable Speed Drives Description: Drives are the largest power consumers in cement making. The energy efficiency of a drive system can be improved by reducing the energy losses or by increasing the efficiency of the motor. Most motors are fixed speed AC models. However, motor systems are often operated at partial or variable load (Nadel, S., M. Shepard, S. Greenberg, G. Katz and A. de Almeida, 1992. Energy Efficient Motor Systems: A Handbook on Technology, Program and Policy Opportunities, ACEEE, Washington, D.C., USA). Also, in cement plants large variations in load occur (Bsche, A., 1993.  Variable Speed Drives in Cement Plants, World Cement 6 24 pp.2-6 (1993)). Within a plant, adjustable speed drives (ASDs) can mainly be applied for fans in the kiln, cooler, preheater, separator and mills, and for various drives. Energy/Environment/Cost/Other Benefits: " Decreasing throttling can reduce energy losses in the system and coupling losses through the installation of ASD. " ASD equipment is used more and more in cement plants (Bsche, A., 1993.  Variable Speed Drives in Cement Plants, World Cement 6 24 pp.2-6 (1993). Fujimoto, S., 1993. Modern Technology Impact on Power Usage in Cement Plants, Proc. 35th IEEE Cement Industry Technical Conference, Toronto, Ontario, Canada, May 1993), but the application may vary widely, depending on electricity costs. " ASDs for clinker cooler fans have a low payback, even when energy savings are the only reason for installing ASDs (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada). " An overview of savings achieved with ASD in a wide array of applications is provided elsewhere (Worrell, E., J.W. Bode, J.G. de Beer, 1997. Energy Efficient Technologies in Industry - Analysing Research and Technology Development Strategies - The 'Atlas' Project, Department of Science, Technology & Society, Utrecht University, Utrecht, The Netherlands). The savings depend on the flow pattern and loads. The savings can be significant (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada) but strongly depend on the application and flow pattern of the system on which the ASD is installed, varying between 7 and 60%. They estimate that the potential savings are 15% for 44% of the installed power, or roughly equivalent to 8 kWh/t cement. " The specific costs depend strongly on the size of the system. For systems over 300 kW the costs are estimated to be 70 ECU/kW (75 US$/kW) or less and for the range of 30-300 kW at 115-130 ECU/kW (120-140 US$/kW) (Worrell, E., J.W. Bode, J.G. de Beer, 1997. Energy Efficient Technologies in Industry - Analysing Research and Technology Development Strategies - The 'Atlas' Project, Department of Science, Technology & Society, Utrecht University, Utrecht, The Netherlands). Using these cost estimates, the specific costs for a modern cement plant, as studied by Bsche (1993), can be estimated to be roughly $0.9 to 1.0/annual tonne cement capacity (Bsche, A., 1993.  Variable Speed Drives in Cement Plants, World Cement 6 24 pp.2-6 (1993). Other estimates vary between $0.4 and $3/annual tonne cement (Holland, M., H. M. Seebach, M., and Ranze, W., 1997. Variable Speed Drives for Roller Presses. Proc.1997 IEEE/PCA Cement Industry Technical Conference XXXIX Conference Record, Institute of Electrical and Electronics Engineers: New Jersey. Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada). Case Studies: " Blue Circle s Bowmanville plant (Canada) installed a variable air inlet fan, reducing electricity and fuel use in the kiln (because of reduced inlet air volume), saving C$75,000/year in energy costs (approximately $47,000 in U.S. dollars) (CIPEC, 2001. Blue Circle Cement Fires Up Energy savings at Ontario Plants, Heads Up CIPEC 5 21 pp.1-2 (2001). Published by Office of Energy Efficiency<, Natural Resources Canada, Ottawa, ON, Canada). " One case study for a modern cement plant estimated potential application for 44% of the installed motor power capacity in the plant (Bsche, A., 1993.  Variable Speed Drives in Cement Plants, World Cement 6 24 pp.2-6 (1993)). " One hypothetical case study estimates the savings at 70%, compared to a system with a throttle valve (or 37% compared with a regulated system) for the raw mill fan, although in practice savings of 70% are unrealistic (Young, G. 2002. Personal communication from Gerald I. Young, Penta Engineering Corp., St. Louis Missouri, March.Bsche, A., 1993.  Variable Speed Drives in Cement Plants, World Cement 6 24 pp.2-6 (1993)). " Lafarge Canada s Woodstock plant replaced their kiln ID fans with ASDs and reduced electricity use by 6 kWh/t (Fujimoto, S., 1994. Modern Technology Impact on Power Usage in Cement Plants, IEEE Transactions on Industry Applications, Vol. 30, No. 3, June). " The United Nations Framework Convention on Climate Change (UNFCCC) reports on several projects utilizing variable frequency drives (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175340468.27/view). For clinker cooler fans at the Chittor Cement Works, Chittorgarh Company, in India, savings ranged from 0.08 to 0.17 kWh/t clinker with costs ranging from 0.012 to 0.013 $/t clinker (0.09 to 0.1 RMB/t clinker). " For raw mill vent fans, savings ranged from 0.25 kWh/t clinker at Birla Cement Works, Chittorgarh Compan, in India to 0.41 kWh/t clinker at Chittor Cement Works Chittorgarh Company, in India. Costs for these were $0.026 and $0.023 /t clinker (0.2 and 0.18 RMB/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175340468.27/view). " For coal mill fans, Birla Cement Works in India found savings of 0.11 and 0.21 kWh/t coal at a cost of 0$.024 and 0.030/t clinker (0.18 and 0.22 RMB/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175340468.27/view). <y 3 B XPP?i]43@5) Ij5yJscfYr <Reduce Leaks in Compressed Air Systems Description: Leaks can be a significant source of wasted energy. A typical plant that has not been well maintained will likely have a leak rate equal to 20 to 50% of total compressed air production capacity (Ingersoll Rand, 2001. Air Solutions Group Compressed Air Systems Energy Reduction Basics, http://www.air.ingersoll-rand.com/NEW/pedwards.htm. June 2001; Price, A. and M.H. Ross, 1989). Leak maintenance can reduce this number to less than 10%. Estimations of leaks vary with the size of the hole in the pipes or equipment. The most common areas for leaks are couplings, hoses, tubes, fittings, pressure regulators, open condensate traps and shut-off valves, pipe joints, disconnects, and thread sealants. A simple way to detect leaks is to apply soapy water to suspect areas. The best way to detect leaks is to use an ultrasonic acoustic detector, which can recognize the high frequency hissing sounds associated with air leaks. After identification, leaks should be tracked, repaired, and verified. Leak detection and correction programs should be ongoing efforts. Energy/Environment/Cost/Other Benefits: " Overall, a 20% reduction of annual energy consumption in compressed air systems is projected for fixing leaks (Radgen, P. and E. Blaustein (eds.), 2001. Compressed Air Systems in the European Union, Energy, Emissions, Savings Potential and Policy Actions, Fraunhofer Institute for Systems Technology and Innovation, Karlsruhe, Germany). " In addition to increased energy consumption, leaks can make air tools less efficient and adversely affect production, shorten the life of equipment, lead to additional maintenance requirements and increase unscheduled downtime. In the worst case, leaks can add unnecessary compressor capacity. Fixing them can alleviate these problems. Vendor Contact information: Compressed air challenge has a variety of resources for compressed air systems. More information can be found at http://www.compressedairchallenge.org/ <7& 4 B XPP?y9]44@7) GN)Dc  < Maintenance of Compressed Air Systems Description: Inadequate maintenance can lower compression efficiency and increase air leakage or pressure variability, as well as lead to increased operating temperatures, poor moisture control, and excessive contamination. Improved maintenance will reduce these problems and save energy. Proper maintenance includes the following (Lawrence Berkeley National Laboratory (LBNL) and Resource Dynamics Corporation, 1998. Improving Compressed Air System Performance, a Sourcebook for Industry, prepared for the U.S. Department of Energy, Motor Challenge Program, Berkeley, CA: LBNL): " Keep the compressor and intercooling surfaces clean and foul-free. Blocked filters increase pressure drop. By inspecting and periodically cleaning filters, the pressure drop may be kept low. Seek filters with just a 1 psig pressure drop over 10 years. Fixing improperly operating filters will also prevent contaminants from entering into tools and causing them to wear out prematurely. Generally, when pressure drop exceeds 14 to 20 kN/m2, replace the particulate and lubricant removal elements, and inspect all systems at least annually. Also, consider adding filters in parallel that decrease air velocity, and, therefore, decrease air pressure drop. " Keep motors properly lubricated and cleaned. Poor motor cooling can increase motor temperature and winding resistance, shortening motor life, in addition to increasing energy consumption. Compressor lubricant should be changed every 2 to 18 months and checked to make sure it is at the proper level. " Inspect drain traps periodically to ensure they are not stuck in either the open or closed position and are clean. Some users leave automatic condensate traps partially open at all times to allow for constant draining. This practice wastes substantial energy and should never be undertaken. Instead, install simple pressure driven valves. Malfunctioning traps should be cleaned and repaired instead of left open. Some auto drains, such as float switch or electronic drains do not waste air. " Maintain the coolers on the compressor to ensure that the dryer gets the lowest possible inlet temperature (Ingersoll Rand, 2001. Air Solutions Group Compressed Air Systems Energy Reduction Basics, http://www.air.ingersoll-rand.com/NEW/pedwards.htm. June 2001). " Check belts for wear and adjust them. A good rule of thumb is to adjust them every 400 hours of operation. " Replace air lubricant separators according to specifications or sooner. Rotary screw compressors generally start with their air lubricant separators having a 14 to 20 kN/m2 pressure drop at full load. When this increases to 70 kN/m2, change the separator (Lawrence Berkeley National Laboratory (LBNL) and Resource Dynamics Corporation, 1998. Improving Compressed Air System Performance, a Sourcebook for Industry, prepared for the U.S. Department of Energy, Motor Challenge Program, Berkeley, CA: LBNL). " Check water cooling systems for water quality (pH and total dissolved solids), flow, and temperature. Clean and replace filters and heat exchangers per manufacturer s specifications. Energy/Environment/Cost/Other Benefits: " The payback for filter cleaning is usually under 2 years (Ingersoll Rand, 2001. Air Solutions Group Compressed Air Systems Energy Reduction Basics, http://www.air.ingersoll-rand.com/NEW/pedwards.htm. June 2001). A 2% reduction of annual energy consumption in compressed air systems is projected for more frequent filter changing (Radgen, P. and E. Blaustein (eds.), 2001. Compressed Air Systems in the European Union, Energy, Emissions, Savings Potential and Policy Actions, Fraunhofer Institute for Systems Technology and Innovation, Karlsruhe, Germany). " Keeping motors properly lubricated and cleaned can help avoid corrosion. " Inspecting and maintaining drains typically has a payback of less than 2 years (Ingersoll Rand, 2001. Air Solutions Group Compressed Air Systems Energy Reduction Basics, http://www.air.ingersoll-rand.com/NEW/pedwards.htm. June 2001). " We assume a savings of 15% on average by implementing< better system-wide maintenance programs. Vendor Contact information: Compressed air challenge has a variety of resources for compressed air systems. More information can be found at http://www.compressedairchallenge.org/ <R 5 B` XPP?1<]45@`8) -0iGĢm:E0 I <Heat Recovery for Water Preheating in Air Compressor Systems Description: As much as 90% of the electrical energy used by an industrial air compressor is converted into heat. In many cases, a heat recovery unit can recover 50 to 90% of this available thermal energy and apply it to space heating, process heating, water heating, makeup air heating, boiler makeup water preheating, drying, cleaning processes, heat pumps, or preheating aspirated air for oil burners (Parekh, P., 2000. Investment Grade Compressed Air System Audit, Analysis, and Upgrade, In: Proceedings 22nd National Industrial Energy Technology Conference Proceedings. Houston, Texas. April 5-6: pp 270-279). It s been estimated that approximately 50 MJ/hour (1.7 kgce/hour) of energy is available for each 0.05 m3/second of capacity (at full load) (Lawrence Berkeley National Laboratory (LBNL) and Resource Dynamics Corporation, 1998. Improving Compressed Air System Performance, a Sourcebook for Industry, prepared for the U.S. Department of Energy, Motor Challenge Program, Berkeley, CA: LBNL). Heat recovery for space heating is not as common with water-cooled compressors because an extra stage of heat exchange is required and the temperature of the available heat is lower, large water cooled compressors being the exception (see below). Energy/Environment/Cost/Other Benefits: " Paybacks are typically less than one year (Galitsky, C., S.C. Chang, E. Worrell, and E. Masanet (2005). Energy Efficiency Improvement and Cost Saving Opportunities for the Pharmaceutical Industry: An ENERGY STAR Guide for Energy and Plant Managers. Lawrence Berkeley National Laboratory, Berkeley, California. Report LBNL-57260). " For large water cooled compressors, recovery efficiencies of 50 to 60% are typical (Lawrence Berkeley National Laboratory (LBNL) and Resource Dynamics Corporation, 1998. Improving Compressed Air System Performance, a Sourcebook for Industry, prepared for the U.S. Department of Energy, Motor Challenge Program, Berkeley, CA: LBNL). " Implementing this measure saves up to 20% of the energy used in compressed air systems annually for space heating (Radgen, P. and E. Blaustein (eds.), 2001. Compressed Air Systems in the European Union, Energy, Emissions, Savings Potential and Policy Actions, Fraunhofer Institute for Systems Technology and Innovation, Karlsruhe, Germany). " We conservatively assume costs equal a payback period of approximately 2 years. Vendor Contact information: Compressed air challenge has a variety of resources for compressed air systems. More information can be found at http://www.compressedairchallenge.org/ <2I  6 Bč XPP?"Z]46@č9) }E63n 4<iReducing the Inlet Air Temperature in Compressed Air Systems Description: Reducing the inlet air temperature reduces energy used by the compressor. In many plants, it is possible to reduce inlet air temperature to the compressor by taking suction from outside the building. Energy/Environment/Cost/Other Benefits: " Importing fresh air can have paybacks of 2 to 5 years (Centre for the Analysis and Dissemination of Demonstrated Energy Technologies (CADDET), International Energy Agency, 1997b. Saving Energy with Efficient Compressed Air Systems, Maxi Brochure 06, Sittard, The Netherlands). " As a rule of thumb, each 3C will save 1% compressor energy use (Centre for the Analysis and Dissemination of Demonstrated Energy Technologies (CADDET), International Energy Agency, 1997b. Saving Energy with Efficient Compressed Air Systems, Maxi Brochure 06, Sittard, The Netherlands; Parekh, P., 2000. Investment Grade Compressed Air System Audit, Analysis, and Upgrade, In: Proceedings 22nd National Industrial Energy Technology Conference Proceedings. Houston, Texas. April 5-6: pp 270-279). " In addition to energy savings, compressor capacity is increased when cold air from outside is used. " We assume 2% savings at a cost equaling a payback period of 3 years. Case Studies: " Case studies in the U.S. manufacturing industrial sector have found an average payback period for importing outside air of less than 1.7 years, but costs can vary significantly depending on facility layout (Industrial Assessment Centers (IAC) (2005). Industrial Assessment Centers Database. Rutgers University, New Brunswick, New Jersey. http://iac.rutgers.edu/database/). Vendor Contact information: Compressed air challenge has a variety of resources for compressed air systems. More information can be found at http://www.compressedairchallenge.org/ <#4 7 B( XPP?@]47@(X:) ߽zMOV r< Compressor Controls in Compressed Air Systems Description: The objective of any control strategy is to shut off unneeded compressors or delay bringing on additional compressors until needed. All units that are on should be running at full-load, except for one. Positioning of the control loop is also important; reducing and controlling the system pressure downstream of the primary receiver can result in energy consumption of up to 10% or more (Lawrence Berkeley National Laboratory (LBNL) and Resource Dynamics Corporation, 1998. Improving Compressed Air System Performance, a Sourcebook for Industry, prepared for the U.S. Department of Energy, Motor Challenge Program, Berkeley, CA: LBNL). Common control strategies for compressed air systems include: " Start/stop (on/off) is the simplest control available and can be applied to reciprocating or rotary screw compressors. For start/stop controls, the motor driving the compressor is turned on or off in response to the discharge pressure of the machine. They are used for applications with very low duty cycles. Applications with frequent cycling will cause the motor to overheat. " Load/unload control, or constant speed control, allows the motor to run continuously but unloads the compressor when the discharge pressure is adequate. In most cases, unloaded rotary screw compressors still consume 15 to 35% of full-load power while delivering no useful work (Lawrence Berkeley National Laboratory (LBNL) and Resource Dynamics Corporation, 1998. Improving Compressed Air System Performance, a Sourcebook for Industry, prepared for the U.S. Department of Energy, Motor Challenge Program, Berkeley, CA: LBNL). " Modulating or throttling controls allow the output of a compressor to be varied to meet flow requirements by closing down the inlet valve and restricting inlet air to the compressor. Throttling controls are applied to centrifugal and rotary screw compressors. " Single master sequencing system controls, which take individual compressor capacities on-line and off-line in response to monitored system pressure demand and shut down any compressors running unnecessarily. System controls for multiple compressors typically offer a higher efficiency than individual compressor controls. " Multi-master controls, which are the latest technology in compressed air system control, are capable of handling four or more compressors and provide both individual compressor control and system regulation by means of a network of individual controllers (Martin, N, E. Worrell, M. Ruth, L. Price, R.N. Elliott, A.M. Shipley, and J. Thorne (2000). Emerging Energy-Efficient Industrial Technologies. Lawrence Berkeley National Laboratory, Berkeley, California. LBNL-46990). The controllers share information, allowing the system to respond more quickly and accurately to demand changes. One controller acts as the lead, regulating the whole operation. This strategy allows each compressor to function at a level that produces the most efficient overall operation. The result is a highly controlled system pressure that can be reduced close to the minimum level required (United States Department of Energy (DOE) (1998). Improving Compressed Air System Performance - A Sourcebook for Industry. Office of Industrial Technologies, Washington, D.C.). Energy/Environment/Cost/Other Benefits: " Energy savings for sophisticated controls are 12% annually (Radgen, P. and E. Blaustein (eds.), 2001. Compressed Air Systems in the European Union, Energy, Emissions, Savings Potential and Policy Actions, Fraunhofer Institute for Systems Technology and Innovation, Karlsruhe, Germany). " Typical payback for start/stop controls is 1 to 2 years. " Load/unload controls can be inefficient. " Changing the compressor control from on/zero/off to a variable speed control can save up to 8% per year (Centre for the Analysis and Dissemination of Demonstrated Energy Technologies (CADDET), International Energy Agency, 1997b. Saving Energy with Efficient Compressed Air Systems, Maxi Brochure 06, Sittard, The Netherlands). " Advanced (multi-master) compressor co<ntrols are expected to deliver energy savings of about 3.5% where applied (Nadel, S., R.N. Elliott, M. Shephard, S. Greenberg, G. Katz and A.T. de Almeida (2002). Energy-Efficient Motor Systems: A Handbook on Technology, Program and Policy Opportunities. American Council for an Energy-Efficient Economy, Washington, D.C.). " In addition to energy savings, the application of controls can sometimes eliminate the need for some existing compressors, allowing extra compressors to be sold or kept for backup. Alternatively, capacity can be expanded without the purchase of additional compressors. Reduced operating pressures will also help reduce system maintenance requirements (United States Department of Energy (DOE) (1998). Improving Compressed Air System Performance - A Sourcebook for Industry. Office of Industrial Technologies, Washington, D.C.). " We assume a savings of 12% of compressed air at a cost of $0.25 US/tonne cement. Vendor Contact information: Compressed air challenge has a variety of resources for compressed air systems. More information can be found at http://www.compressedairchallenge.org/ <Bcr 8 B XPP?,]48@D<) ׋@+YN. <- Sizing Pipe Diameter Correctly in Compressed Air Systems Description: Inadequate pipe sizing can cause pressure losses, increase leaks and increase generating costs. Pipes must be sized correctly for optimal performance or resized to fit the current compressor system. Energy/Environment/Cost/Other Benefits: " Increasing pipe diameter typically reduces annual energy consumption by 3% (Radgen, P. and E. Blaustein (eds.), 2001. Compressed Air Systems in the European Union, Energy, Emissions, Savings Potential and Policy Actions, Fraunhofer Institute for Systems Technology and Innovation, Karlsruhe, Germany). Further savings can be realized by ensuring other system components (for example, filters, fittings, and hoses) are properly sized. " We estimate costs to be $0.5/kWh saved based on implementing this measure in other industries (Galitsky, C., E. Worrell and A. Radspieler of LBNL and P. Healy and S. Zechiel of Fetzer Vineyards. 2005. BEST Winery Guidebook: Benchmarking and Energy and Water Savings Tool for the Wine Industry. Berkeley, CA: Lawrence Berkeley National Laboratory, May, LBNL 3184). Vendor Contact information: Compressed air challenge has a variety of resources for compressed air systems. More information can be found at http://www.compressedairchallenge.org/ < 9 B XPP?(]49@<) 'Bf^  <; Replace Mercury Lights by Metal Halide or High Pressure Sodium Lights for Plant Wide Lighting Description: Replacement of mercury lamps by metal halide can increase energy efficiency while improving color rendition and increasing light levels. High pressure sodium lamps can save even more energy where color or lighting levels are less important. Energy/Environment/Cost/Other Benefits: " Where color rendition is critical, metal halide lamps can replace mercury or fluorescent lamps with an energy savings of 50% (Price, A. and M.H. Ross, 1989. Reducing Industrial Electricity Costs  an Automotive Case Study, The Electricity Journal. July: 40-51). " Where color rendition is not critical, high pressure sodium lamps offer energy savings of 50 to 60% compared to mercury lamps (Price, A. and M.H. Ross, 1989. Reducing Industrial Electricity Costs  an Automotive Case Study, The Electricity Journal. July: 40-51). " We assume a savings of 4% of lighting electricity use at a cost of $0.1 U.S./tonne cement. Vendor Contact information: More information on lighting systems, lamps, ballasts, luminaries, controls and day-lighting can be obtained from the U.S. Department of Energy s Energy Efficiency and Renewable Energy Program at http://www.eere.energy.gov/buildings/info/components/lighting/. <p : BT XPP?[.]4:@T>) vȖ@7$ <)Lighting Control for Plant Wide Lighting Description: Lights can be shut off during non-working hours by automatic controls, such as occupancy sensors that turn off lights when a space becomes unoccupied. Numerous case studies throughout the United States suggest that the average payback period for occupancy sensors is approximately 1 year (Industrial Assessment Centers (IAC) (2005). Industrial Assessment Centers Database. Rutgers University, New Brunswick, New Jersey. http://iac.rutgers.edu/database/). Manual controls can also be used in addition to automatic controls to save additional energy in smaller areas. Manual controls can be used in conjunction with automatic controls to save additional energy in smaller areas. One of the easiest measures is to install switches to allow occupants to control lights. Other lighting controls include daylight controls for indoor and outdoor lights, which adjust the intensity of electrical lighting based on the availability of daylight. Energy/Environment/Cost/Other Benefits: " Occupancy sensors can save up to 10% to 20% of facility lighting energy use (Galitsky, C., S.C. Chang, E. Worrell, and E. Masanet (2005a). Energy Efficiency Improvement and Cost Saving Opportunities for the Pharmaceutical Industry: An ENERGY STAR Guide for Energy and Plant Managers. Lawrence Berkeley National Laboratory, Berkeley, California. Report LBNL-57260). " Payback of lighting control systems is generally less than 2 years. Vendor Contact information: More information on lighting systems, lamps, ballasts, luminaries, controls and day-lighting can be obtained from the U.S. Department of Energy s Energy Efficiency and Renewable Energy Program at http://www.eere.energy.gov/buildings/info/components/lighting/. <! ; B XPP?i']4;@>) IɠID|]!% <- Replace Magnetic Ballasts with Electronic Ballasts for Plant-wide Lighting Description: A ballast is a mechanism that regulates the amount of electricity required to start a lighting fixture and maintain a steady output of light. Older magnetic ballasts can be replaced with newer electronic ballasts to save energy. Energy/Environment/Cost/Other Benefits: " Electronic ballasts save 12-25 percent more power than their magnetic predecessors do (United States Environmental Protection Agency (U.S. EPA), 2001.  Green Lights Program (Part of the ENERGY STAR Program), http://es.epa.gov/partners/green/green.html). " New electronic ballasts have smooth and silent dimming capabilities, in addition to longer lives (up to 50% longer), faster run-up times, and cooler operation than magnetic ballasts (Eley, C., T. M. Tolen, J. R. Benya, F. Rubinstein and R. Verderber (1993). Advanced Lighting Guidelines: 1993. California Energy Commission, Sacramento, California. Cook, B. (1998). High-efficiency Lighting in Industry and Commercial Buildings. Power Engineering Journal. October: 197-206). " New electronic ballasts also have automatic switch-off capabilities for faulty or end-of-life lamps " We assume a savings of 8% and a cost of $0.12 U.S./tonne cement. Vendor Contact information: More information on lighting systems, lamps, ballasts, luminaries, controls and day-lighting can be obtained from the U.S. Department of Energy s Energy Efficiency and Renewable Energy Program at http://www.eere.energy.gov/buildings/info/components/lighting/. <' < B XPP?i.]4<@@) ),]1DH䡪 <Replace Metal Halide High-intensity discharge with High-Intensity Fluorescent Lights for Plant-wide Lighting Description: Traditional High-intensity discharge (HID) lighting can be replaced with high-intensity fluorescent lighting. These new systems incorporate high-efficiency fluorescent lamps, electronic ballasts and high-efficacy fixtures that maximize output to the work plane. Energy/Environment/Cost/Other Benefits: " Advantages to the new system are many; they have lower energy consumption, lower lumen depreciation over the lifetime of the lamp, better dimming options, faster start-up and restrike capability, better color rendition, higher pupil lumens ratings and less glare (Martin, G., T. Lange, and N. Frewin. 2000. Next Generation Controllers for Kiln/Cooler and Mill Applications based on Model predictive Control and Neural Networks, Proceedings IEEE-IAS/PCA 2000 Cement Industry Technical Conference, Salt Lake City, UT, May 7th  12th). " High-intensity fluorescent systems yield 50% electricity savings over standard metal halide HID. " Dimming controls that are impractical in the metal halide HIDs can be applied and also save significant energy. " Retrofitted systems cost about $185 per fixture, including installation costs (Martin, G., T. Lange, and N. Frewin. 2000. Next Generation Controllers for Kiln/Cooler and Mill Applications based on Model predictive Control and Neural Networks, Proceedings IEEE-IAS/PCA 2000 Cement Industry Technical Conference, Salt Lake City, UT, May 7th  12th). " In addition to energy savings and better lighting qualities, high-intensity fluorescents can help improve productivity and have reduced maintenance costs. " We assume a savings of 20% at a cost of $0.16 U.S. /tonne cement. Vendor Contact information: More information on lighting systems, lamps, ballasts, luminaries, controls and day-lighting can be obtained from the U.S. Department of Energy s Energy Efficiency and Renewable Energy Program at http://www.eere.energy.gov/buildings/info/components/lighting/. <[& = B XPP?$]4=@0A) &cwDH{ڂN <+ Replace T-12 Tubes by T-8 Tubes for Plant-wide Lighting Description: In many industrial facilities it is common to find T-12 lighting tubes in use. T-12 lighting tubes are 12/8 inches (or 3.8 cm) in diameter (the  T designation refers to a tube s diameter in terms of 1/8 inch increments). The initial output for these lights is high, but energy consumption is also high. They also have extremely poor efficacy, lamp life, lumen depreciation, and color rendering index. Because of this, maintenance and energy costs are high. Using T-8 lamps (lamps with a smaller diameter, of 1 inch or 2.54 cm) will increase the efficiency. Energy/Environment/Cost/Other Benefits: " Replacing T-12 lamps with T-8 lamps approximately doubles the efficacy of the former. " T-8 tubes can last up to 60% longer than T-12 tubes. " We assume a savings of 15% and costs of $0.25U.S./tonne cement. Vendor Contact information: More information on lighting systems, lamps, ballasts, luminaries, controls and day-lighting can be obtained from the U.S. Department of Energy s Energy Efficiency and Renewable Energy Program at http://www.eere.energy.gov/buildings/info/components/lighting/. <@*` P B䐖 XPP?rns]4P@䐖C) xZ{:Nj9;yAd <+Fan Modifications and Optimization in All Kilns Description: Increasing the inlet duct of the kiln fan can reduce friction loss and pressure loss during flow of air through the duct, saving energy. Although savings are small, modifications like these have very small capital investments. Energy/Environment/Cost/Other Benefits: " See case studies for detailed information on these benefits Case Studies: " Chittor Cement Works, Chittorgarh Company in India modified their inlet duct of the cooler fan by increasing its diameter to reduce friction and pressure loss during flow of air through the duct (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175340468.27/view). They found electricity savings of 0.0.048 kWh/t clinker (6 kW). Capital costs were only $0.01305 INR per tonne of clinker (0.00225 RMB/t clinker). <  Q BH XPP?r]4Q@HxC) #[XMt  Z< Improved Refractories for Clinker Making in All Kilns Description: There can be considerable heat losses through the shell of a cement kiln, especially in the burning zone. The use of better insulating refractories (for example Lytherm) can reduce heat losses (Venkateswaran, S.R. and H.E. Lowitt. 1988. The U.S. Cement Industry, An Energy Perspective, U.S. Department of Energy, Washington D.C., USA). Refractory choice is the function of insulating qualities of the brick and the ability to develop and maintain a coating. The coating helps to reduce heat losses and to protect the burning zone refractory bricks. Refractories protect the steel kiln shell against heat, chemical and mechanical stress. The choice of refractory material depends on the combination of raw materials, fuels and operating conditions. Refractories are made by foreign companies operating in China, particularly in the Liaoning Province, such as Refratechnik (German) and RHI (Austrian). China also produces medium and smaller refractories but the energy efficiency is poorer than those made by the leading international companies (Cui, Y., 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC)). Energy/Environment/Cost/Other Benefits: " Extended lifetime of the higher quality refractories will lead to longer operating periods and reduced lost production time between relining of the kiln, and, hence, offset their higher costs (Schmidt, H-J. 1998. Chrome Free Basic Bricks  A Determining Factor in Cement Production Proc.1998 IEEE-IAS/PCA Cement Industry Technical Conference: 155-167; Van Oss, H. 2002. Personal Communication. U.S. Geological Survey, March  May, 2002). " The use of improved kiln-refractories may also lead to improved reliability of the kiln and reduced downtime, reducing production costs considerably, and reducing energy needs during start-ups. " Estimates suggest that the development of high-temperature insulating linings for the kiln refractories can reduce fuel use by 0.12 to 0.4 GJ/t (4.1 to 13 kgce/t) of clinker (Lowes, T.M. and Bezant, K.W. 1990. Energy Management in the UK Cement Industry Energy Efficiency in the Cement Industry (Ed. J. Sirchis), London, England: Elsevier Applied Science.; COWIconsult, March Consulting Group and MAIN. 1993. Energy Technology in the Cement Industrial Sector, Report prepared for CEC - DG-XVII, Brussels, April 1992.; Venkateswaran, S.R. and H.E. Lowitt. 1988. The U.S. Cement Industry, An Energy Perspective, U.S. Department of Energy, Washington D.C., USA). " Costs for insulation systems are estimated to be $0.25/annual tonne clinker capacity (Lesnikoff, G. 1999. Hanson Cement, Cupertino, CA, personal communication). " Structural considerations may limit the use of new insulation materials. Case Studies: " In one vertical shaft kiln in South China, a new energy-efficient lining was applied. Fuel consumption was reduced from 930 to 950 kcal/kg clinker (133 to 136 kgce/t clinker) to 800 to 820 kcal/kg clinker (116 to 119 kgce/t clinker), a savings of approximately 14% (Institute of Technical Information for Building Materials Industry (ITIBMIC). 2004. Final Report on Cement Survey. Prepared for the United Nations Industrial Development Organization (UNIDO) for the Contract Entitled Cement Sub-sector Survey for the Project Energy Conservation and GHG Emissions Reduction in Chinese TVEs-Phase II. Contract no. 03/032/ML, P.O. No. 16000393, September 9). The output also increased by about 1 tonne per hour. " Another cement plant in North China utilizing vertical shaft kilns employed energy efficient lining and found a reduction of fuel use from 900 to 920 kcal/kg clinker (130 kgce/t clinker) to about 800 kcal/kg clinker (116 kgce/t clinker) (Institute of Technical Information for Building Materials Industry (ITIBMIC). 2004. Final Report on Cement Survey. Prepared for the United Nations Industrial Development Organization (UNIDO) for the Contract Entitled Cement Sub-sector Survey for the Project Energy Conservation an<d GHG Emissions Reduction in Chinese TVEs-Phase II. Contract no. 03/032/ML, P.O. No. 16000393, September 9). The output of the kiln also increased per unit of raw materials input. " Changjiang Cement Factory in Zhejiang City, Jangsu Province applied energy saving kiln lining to its shaft kiln and found energy savings of 0.46 to 0.63 GJ/t clinker (16 to 22 kgce/t clinker) (Institute of Technical Information for Building Materials Industry (ITIBMIC). 2004. Final Report on Cement Survey. Prepared for the United Nations Industrial Development Organization (UNIDO) for the Contract Entitled Cement Sub-sector Survey for the Project Energy Conservation and GHG Emissions Reduction in Chinese TVEs-Phase II. Contract no. 03/032/ML, P.O. No. 16000393, September 9). In addition to these energy savings, they were able to increase production. < _]Z R B XPP?rzs]4R@dE) LOAߜ{- )< Energy Management and Process Control Systems for Clinker Making in All Kilns Description: Heat from the kiln may be lost through non-optimal process conditions or process management. Automated computer control systems may help to optimize the combustion process and conditions. Improved process control will also help to improve the product quality and grindability, for example reactivity and hardness of the produced clinker, which may lead to more efficient clinker grinding. A uniform feed allows for steadier kiln operation, thereby saving ultimately on fuel requirements. In cement plants across the world, different systems are used, marketed by different manufacturers. Most modern systems use so-called 'fuzzy logic' or expert control, or rule-based control strategies. If automatic controls are going to be successfully implemented, they must link all processes from mine management to raw materials input into the kiln to kiln fuel input in order to realize stable production; none should be done manually ( Institute of Technical Information for Building Materials Industry (ITIBMIC). 2004. Final Report on Cement Survey. Prepared for the United Nations Industrial Development Organization (UNIDO) for the Contract Entitled Cement Sub-sector Survey for the Project Energy Conservation and GHG Emissions Reduction in Chinese TVEs-Phase II. Contract no. 03/032/ML, P.O. No. 16000393, September 9). Expert control systems do not use a modeled process to control process conditions, but try to simulate the best human operator, using information from various stages in the process. One such system, called ABB LINKman, was originally developed in the United Kingdom by Blue Circle Industries and SIRA (Energy Technology Support Unit (ETSU). 1988. High Level Control of a Cement Kiln, Energy Efficiency Demonstration Scheme, Expanded Project Profile 185, Harwell, United Kingdom). The LINKman system has successfully been used in rotary kilns (both wet and dry). Other developers also market  fuzzy logic control systems, for example, F.L. Smidth (Denmark) Krupp Polysius (Germany) and Mitsui Mining (Japan). An alternative to expert systems or fuzzy logic is model-predictive control using dynamic models of the processes in the kiln. Additional process control systems include the use of on-line analyzers that permit operators to instantaneously determine the chemical composition of raw materials being processed, thereby allowing for immediate changes in the blend of raw materials. Several companies in China provide optimized information technology for energy management and process control, such as the ABB or the Chinese software company Yun Tian (Wang, Yanjia of Tsinghua University, Beijing, China. 2006b. Personal written communication). In cement plants across the world, different systems are used, marketed by different manufacturers. After their first application in 1985, modern control systems now find wider application and can be found in many European plants. Most technologies for this measure are made by international companies such as Siemens and ABB; few if any are made by domestic companies (Cui, Y., 2004 and 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC)). Energy/Environment/Cost/Other Benefits: " Energy savings from process control systems may vary between 2.5% and 10% (Energy Technology Support Unit (ETSU). 1988. High Level Control of a Cement Kiln, Energy Efficiency Demonstration Scheme, Expanded Project Profile 185, Harwell, United Kingdom; Haspel, D., and W. Henderson. 1993. A New Generation of Process Optimisation Systems, International Cement Review, June: 71-73; Ruby, C.W. 1997. A New Approach to Expert Kiln Control. Proc.1997 IEEE/PCA Cement Industry Technical Conference XXXIX Conference Record, Institute of Electrical and Electronics Engineers: New Jersey), and the typical savings are estimated to be 2.5 to 5%. " All control systems described here report typical energy savings of 3 to 8%, while improving productivity of the kiln. F< or example, Krupp Polysius reports typical savings of 2.5  5%, with similar increased throughput and increased refractory life of 25  100%. " The economics of advanced process control systems are very good and payback periods can be as short as 3 months (Energy Technology Support Unit (ETSU). 1988. High Level Control of a Cement Kiln, Energy Efficiency Demonstration Scheme, Expanded Project Profile 185, Harwell, United Kingdom). " A payback period of 2 years or less is typical for kiln control systems, while often much lower payback periods are achieved (Energy Technology Support Unit (ETSU). 1988. High Level Control of a Cement Kiln, Energy Efficiency Demonstration Scheme, Expanded Project Profile 185, Harwell, United Kingdom. Martin, G. and S. McGarel. 2001a. Automation Using Model Predictive Control in the Cement Industry. Pavillion Technologies, Inc., Austin, TX (based on a paper published in International Cement Review, February: 66-67). Available at: http://www.pavtech.com/). " Process control of the clinker cooler can help to improve heat recovery, material throughput and improved control of free lime content in the clinker, and to reduce NOx emissions (Martin, G., T. Lange, and N. Frewin. 2000. Next Generation Controllers for Kiln/Cooler and Mill Applications based on Model predictive Control and Neural Networks, Proceedings IEEE-IAS/PCA 2000 Cement Industry Technical Conference, Salt Lake City, UT, May 7th  12th). Installing a Process Perfecter (of Pavilion Technologies Inc.) has increased cooler throughput by 10%, reduced free lime by 30% and reduced energy by 5%, while reducing NOx emissions by 20% (Martin, N., E. Worrell, and L. Price. 1999. Energy Efficiency and Carbon Dioxide Emissions Reduction Opportunities in the U.S. Cement Industry. Lawrence Berkeley National Laboratory, Berkeley, CA. September. (LBNL-44182); Martin, G., S. McGarel, T. Evans, and G. Eklund. 2001. Reduce Specific Energy Requirements while Optimizing NOx Emissions Decisions in Cement with Model Predictive Control, Personal Communication from Pavilion Technologies, Inc., Austin, TX, December 3). The installation costs equal $0.35/annual tonne of clinker, with an estimated payback period of 1 year (Martin, G., S. McGarel, T. Evans, and G. Eklund. 2001. Reduce Specific Energy Requirements while Optimizing NOx Emissions Decisions in Cement with Model Predictive Control, Personal Communication from Pavilion Technologies, Inc., Austin, TX, December 3). " Combustion control in vertical kilns is more difficult than in rotary kilns where the flow of raw materials is controlled by a mechanically-rotating horizontally-oriented shaft at a slight angle instead of just gravity (Liu, F., M. Ross and S. Wang. 1995. Energy Efficiency of China s Cement Industry. Energy 20 (7): 669-681). In these kilns, operating skills and hence, proper training is more important for energy efficiency and product quality. " Control technologies also exist for controlling the air intake. (For more information on kiln combustion system improvements and controls for VSKs, see  kiln combustion system improvements for Clinker Production  Vertical Shaft Kilns). " Raw materials and fuel mix can be improved by a careful analysis of the chemical and physical characteristics of each, and by automating the weighing process and the pellet production (water content and raw feed mixtures), the blending process, the kiln operation (optimizing air flow, temperature distribution, and the speed of feeding and discharging). Case Studies: " Expert control systems. Ash Grove implemented a fuzzy control system at the Durkee Oregon plant in 1999. " The first ABB LINKman system was installed at Blue Circle's Hope Works in 1985 in the U.K., which resulted in a fuel consumption reduction of nearly 8% (Energy Technology Support Unit (ETSU). 1988. High Level Control of a Cement Kiln, Energy Efficiency Demonstration Scheme, Expanded Project Profile 185, Harwell, United Kingdom). The control system required investing 203,000 (1987), equivalent to $0.3/annual tonne clinker (Energy Technology Su<pport Unit (ETSU). 1988. High Level Control of a Cement Kiln, Energy Efficiency Demonstration Scheme, Expanded Project Profile 185, Harwell, United Kingdom), including measuring instruments, computer hardware and training. " A model predictive control system was installed at a kiln in South Africa in 1999, reducing energy needs by 4%, while increasing productivity and clinker quality. The payback period of this project is estimated to be 8 months, even with typically very low coal prices in South Africa (Martin, G. and S. McGarel. 2001a. Automation Using Model Predictive Control in the Cement Industry. Pavillion Technologies, Inc., Austin, TX (based on a paper published in International Cement Review, February: 66-67). Available at: http://www.pavtech.com/). " On-line analyzer: Blue Circle s St. Marys plant (Canada) installed an on-line analyzer in 1999 in its precalciner kiln, and achieved better process management as well as fuel savings. Holderbank (1993) notes an installation cost for on-line analyzers of $0.8 to 1.7/annual tonne clinker (Holderbank Consulting, 1993. Present and Future Energy Use of Energy in the Cement and Concrete Industries in Canada, CANMET, Ottawa, Ontario, Canada). " Process controls: installation of float switches with high level limit sensors in the overhead tanks for water coolers at the Birla Cement Works, Chittorgarh in India reduced power consumption by cutting off power supply to the water pump when it fills to the high level. The pump restarts when water reaches the low level. This eliminates overflow from tank and saved 0.08 kWh/t clinker. The cost of this measure was 0.328 INR/t clinker (0.06 RMB/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175340468.27/view) . " Fan systems management: when production volume increased, the installation of an expanded 3-fan system to handle the vertical roller mill, the preheater and the electrostatic precipitator at the Satna Cement Works, Birla Corporation, Limited in India helped reduce power consumption by avoiding false air entry into the preheater (from the roller mill) and saving power of the electrostatic precipitator. Power savings were 2.3 kWh/t clinker at a cost of 42 INR/t clinker (7.2 RMB/t clinker) (The United Nations Framework Convention on Climate Change (2008) CDM project documents available at: http://cdm.unfccc.int/Projects/DB/SGS-UKL1175340468.27/view). <) S B XPP?r]4S@E) mShoD@x$94 = <{Adjustable Speed Drive for Kiln Fan for Clinker Making in All Kilns Description: Adjustable or variable speed drives (ASDs) for the kiln fan result in reduced power use and reduced maintenance costs. ASDs are currently being made in China, although many of the parts and instrumentation are still being imported from Germany and/or Japan (Cui, Y., 2004 and 2006. Personal communication with Prof. Cui Yuansheng, VP of the Institute of Technical Information for Building Materials Industry of China (ITIBMIC)). Energy/Environment/Cost/Other Benefits: " See case studies for detailed information on these benefits Case Studies: " The use of ASDs for a kiln fan at the Hidalgo plant of Cruz Azul Cement in Mexico resulted in improved operation, reliability and a reduction in electricity consumption of almost 40% (Dolores, R. and M.F. Moran. 2001. Maintenance and Production Improvements with ASDs Proc.2001 IEEE-IAS/PCA Cement Industry Technical Conference: 85-97). for the 1,000 horsepower motors. The replacement of the damper by an ASD was driven by control and maintenance problems at the plant. The energy savings may not be typical for all plants, as the system arrangement of the fans was different from typical kiln arrangements. " Fujimoto, (1994) notes that Lafarge Canada s Woodstock plant replaced their kiln fans with ASDs and reduced electricity use by 5.5 kWh/t of cement (6.1 kWh/t clinker) (Fujimoto, S., 1994. Modern Technology Impact on Power Usage in Cement Plants, IEEE Transactions on Industry Applications, Vol. 30, No. 3, June). " The Zhonglida Group, operating ten cement enterprises (with both VSKs and new dry rotary kilns), installed variable speed drives in 40 large motors (over 55 kW) and over 40 of its smaller motors (< 55 KW) and found energy savings of over 30% (Institute of Technical Information for Building Materials Industry (ITIBMIC). 2004. Final Report on Cement Survey. Prepared for the United Nations Industrial Development Organization (UNIDO) for the Contract Entitled Cement Sub-sector Survey for the Project Energy Conservation and GHG Emissions Reduction in Chinese TVEs-Phase II. Contract no. 03/032/ML, P.O. No. 16000393, September 9). " Birla Vikas Cement Works installed a slip power recovery system for precalciner speed control (from 70 to 100% speed) in its kiln to replace a liquid rotor regulator. 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