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China National Electric Wire & Cable Import & Export Corp. |
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Quality, Efficient and Cost |
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Low-Temperature Waste Heat Power Generation Technology In Chinese Cement Industry (Waste Heat Recovery Power Plant of Cement Factory)
History
Through several generation unremitting efforts, China cement industry has achieved remarkable progress both is output scale and energy saving. The production scale has been improved from 1,000t/d and 2,500t/d to 5,000t/d, 10,000t/d; clinker heat consumption has declined to 300~3300kj/kg from original 4600~6700kj/kg, large amount medium-low temperature waste heat below 400’C in cement production process has not been recovered, which results in amazing energy waste. In 1990, National plan committee entrust the National Building Material Bureau to study and develop the medium & low temperature waste heat power generation technique and equipments for cement production lines, and then several institute was entrusted to take the job of National import technology project—“Eight Five-year Plan”—Medium and low temperature waste heat power generation with supplement boiler technique and equipments. Through unremitting efforts in “Eight Five-year Plan” period, cooperating with the related corporations and institutes, China institutes and manufacturers successfully finished the work, received the “Eight Five-year Plan Important and Large Technology Achievement Praise”. By utilizing the technique, China institutes and manufacturers successfully utilize the waste heat of below 400’C exhausted from the clinker production line, and apply the technique in the production lines with different output. Amount of medium and low temperature waste heat power stations with different installed capacity and supplement boilers has been put into production in different production lines from 1000t/d to 5000t/d. The installed capacity of the power stations arranged from 6MW to 25MW.
In the middle of 1980s, in order to actively respond to the resources comprehensive utilization policy advocated by the government, China institutes and manufacturers independently developed resource comprehensive utilization power generation technique and equipments. By adopting circulating fluidized bed boilers as supplement as supplement boilers, burning coal marl which heat value should be less than 12560kj/kg, recovering the ash discharged from the boiler to cement production, ,fully recovering the medium low temperature waste heat exhausted from the clinker production lines, both the considerable economic profit and the social benefit and environmental benefit can be realized. The successful application of the technique, not only accord with the circulating economy and sustained development strategy, but also makes an effort and contributes to the resource comprehensive utilization project of China.
In the late of 1960s, foreign countries started the research on pure medium and low temperature waste heat power generation process, in the middle of 1970s, both thermodynamic system and equipment have been applied to practice use. In the early 1980s the application burst, especially in Japan the technique has been not only applied in domestic 20-odd pre-calcining cement production lines but also exported to Taiwan, Korea and so on. It is proved that Japanese-developed waste heat boiler and medium and low quality steam turbine are mature and reliable through operation experiences in several ten plants. In 1996 Japan NEDO presented a set of 6480KW pure medium and low temperature waste heat power station equipment to Anhui Ningguo Cement Plant, which matches with the plant 4000t/d pre calcining kiln, China institutes and manufacturers has undertaken technical transformation and cooperated to accomplish design and development, the station was put into operation in 1998. With the successful development of low parameter and multi-inlet turbine(China institutes and manufacturers cooperating with turbine manufactures for the work), pure medium and low temperature waste heat power station adopting Chinese-made equipment becomes mature. The energy saving effect is much more remarkable by adopting the pure medium and low temperature WHG technology. In April 2003, in Shanghai Wanan Group Jinshan Cement Plant(1200t/d four-stage cement clinker production line), the first generation pure low temperature waste heat power station all adopting Chinese-made equipment designed by Chinese manufacturers has been put into normal operation, the power station installed capacity is 2500kw, normal power generation 1900~2100kw, power generation amount per ton clinker attains 38~40kw, which means the advanced level of the same type power stations in the world. In July 2004, in Guangxi Liuzhou Cement Plant(3600t/d four-stage cement clinker production line), a pure low temperature waste heat power station, adopting import equipment in key parts, designed by Chinese institues has been put into normal operation, the power station installed capacity is 6000kw, normal power generation 5900kw, power generation amount per ton clinker attains 38~40kw, which meets the advanced level of the same type power stations in the world. In march 2005, in Zhejiang Shenhe Cement Co., Ltd.(2500t/d five-stage clinker production line), the first generation experimental pure low temperature waste heat power station, all adopting Chinese equipments, designed by China institutes and manufacturers has been pt into normal operation, the power station installed capacity is 3000kw, normal power generation 2800~2900kw, power generation amount per ton clinker attains 26~28kw, which meets the advanced level of the same type power station in the world. In June 2005, in Zhejiang Xiaopu Zhongsheng Cement Co., Ltd.(2500t/d five-stage clinker clinker production line), the first generation modified pure low temperature waste heat power station, all adopting Chinese-made equipments, designed by China institutes and manufacturers has been put into normal operation, the power station installed capacity is 3000kw, normal temperature generation 3200~3300k, power generation amount per ton clinker attains 30~32kw, which meets the advanced level of the same type power station in the world. In July 2005, in Zhejiang Meishan Zhongsheng Cement Co., Ltd.(5000t/d five-stage clinker production line), the first generation experimental pure low temperature waste heat power station, all adopting Chinese-made equipments, designed by China institutes and manufacturers has been put into normal operation, the power station installed capacity is 6000kw, normal power generation 6600~6800kw, power generation amount per ton clinker attains 31~33kw, which meets the advanced level of the same type power stations in the world. In September 2005, in Zhejiang Leomax Cement Co., Ltd.(2500t/d+5000t/d five-stage clinker production lines), the first generation experimental pure low temperature waste heat power station all adopting Chinese-made equipments, designed by China institutes and manufacturers has been put into normal operation, the power station installed capacity is 3000kw+6000kw, normal power generation 9600~10000kw, power generation amount per ton clinker attains 30~32kw, which meets the advanced level of the same type power stations in the world. In May 2006, in Hainan Huashengtianya Cement Co., Ltd.(5000t/d five-stage clinker production line), the first generation modified pure low temperature waste heat power station, all adopting Chinese-made equipments, designed by Chinese Institutes has been put into normal operation, the power station installed capacity is 6000kw, amount per ton clinker attains 32~34kw, which meets the advanced level of the same type power stations in the world. Through unremitting efforts in waste heat utilization of clinker burning system, China institutes and manufacturers has designed more than 20 pure waste heat power stations and put them into operation successfully. Especially, with the successful operation of Zhejiang Shenhe 3000kw pure low temperature power station, Zhejiang Xiaopu Zhongsheng 3000kw pure low temperature power station, Zhejiang Meishan Zhongsheng 6000kw pure low temperature power station, Zhejiang Leomax 3000kw+6000kw pure low temperature power station, and Huashengtianya 6000kw pure low temperature power station, Chinese pure low temperature waste heat power generation technology becomes mature and step in the application stage. China institutes and manufacturers aims to promote the cement industry to realize energy saving, environmental promote the cement industry to realize energy saving, environmental protection, sustained development and environmentally-friendly society. At the same time, China institutes and manufacturers also contribute to the study, development and application in these fields. Up to now, China institutes and manufacturers has many put pure low temperature waste heat power station into operation in 10 cement production lines of different clinker output, including three 5000t/d five-stage clinker production lines, five 2500t/d five-stage clinker production lines, and two 2500t/d five-stage clinker production lines. With the farther experimental sum-up and solution optimization, the third generation pure low temperature waste heat power stations designed by China institutes and manufacturers will be put into operation in succession, the power generation amount per ton clinker of which will be reach or exceed 38kwh, the technology and equipment will reach a new level. With the successful operation of more and more waste heat power stations designed by China institutes and manufacturers, large of the production cost has been saved, at the same time energy saving, environment protection have been realized, receive good economic profit and social profit provide a new concept for the ladderlike development and comprehensive utilization of energy, and set an example for the technology developing of Chinese cement industry.
The Technical Solution Of Pure Low Temperature Waste Heat Power Generation station For 2500t/d Cement Production Line
Take consideration of the process flow, layout, power supply and distribution , and waste of the clinker production line, by utilizing the heat resource exhausted from the pre heater and cooler, one 4500kw pure low temperature waste heat power station is appropriate for the 2500t/d clinker production line.
Waste heat resource The waste heat source of the cement line can be utilized as follows: 2500t/d cement production line kiln outlet cooler waste heat condition after reformation will be 6500Nm3/h-350℃. The waste gas will be introduced into the kiln outlet waste heat boiler (AQC boiler) for power generation ; Outlet waste gas of the AQC boiler will be introduced into the existing kiln outlet EP. Kiln inlet five-stage pre heater waste gas condition will be 150000Nm3/h-340℃. The waste gas will be into the kiln inlet waste heat boiler(SP boiler) for power generation and the exhausted gas temperature should be higher than 220℃ for raw mill drying.
Power supply and connection system solution At the beginning of the power station putting into production, 300~500kw start-up power supply is necessary which will be supplied by the general substation. After the generation putting into production, the generation will be connected to outside power network by general substation 6(10) kV. The power station and the existing system will be connecting to the outside power network, but not feed power to it. The power consumption of the station will be supplied by general substation or generator. In order to make sure the power station run in reason and smoothly, a high & low voltage distribution room should be plotted on the side of the main building. As the waste heat power station of the company, the generation power should be fed to the cement production line. The power station and existing system will be connected to outside power network, but not feed power to it. Connection synchronous points will be set at generator liaison switch and generator outlet switch.
Water supply Since the average production and domestic water consumption will be about 900m3 /d, the water supply capacity should be 1100m3/d.
4. Technical safeguard condition 4.1Thermodynamic system According to the process flow and design parameter of 2500t/d cement production line, adopting China institutes and manufacturers pure low temperature waste heat recovery technique and Chinese-made equipments, the power generation amount per ton clinker can achieve 36~38kwh. 4.2 Brief introduction of technical solution 4.2.1 Kiln outlet waste heat boiler-AQC boiler The AQC boiler is arranged between cooler middle stage and the existing kiln outlet EP. The heat-receiving surface of the AQC boiler is divided into two stages: the first stage produces steam, and the second stage produces hot water. The saturation water of 135℃ will be feed to the AQC boiler steam stage and kiln inlet waste heat boiler (hereinafter called SP boiler); 1.6MPa superheated steam produced in AQC boiler steam stage and SP boiler merges together and is introduced to a turbine for power generation. Condensing water of the turbine is pumped to AQC boiler hot water stage.
4.2.2 Kiln inlet waste heat boiler-SP boiler The SP boiler is at the outlet of pre heater. The superheated steam produce in SP boiler and AQC boiler steam stage merges together and is introduced to a turbine for power generation.
4.2.3 One condensing steam turbine is adopted to match the low temperature waste heat power station A Chinese-made condensing steam turbine is adopted, rated power is 4500kw, and initial steam parameter is 1.27Mpa-290℃
4.2.4 One generator is selected to match the condensing turbine One normal 6(10) kv AC generator with 4500kw rated power is adopted, which will be connected to outside power network by general substation 6(10) kV.
4.2.5 Circulation cooling water system will be adopted for meeting the cooling water demand of the power station. 4.2.6 A”Filter+ demineralizing”system is adopted as chemical water treatment for meeting the boiler water criterion. 4.2.7 DCS computer control system is adopted for monitoring the power station running.
4.3 Main equipments
Main technical economy index
The Technical Solution Of Low Temperature Waste Heat Power Generation station For 2*2500t/d Cement Production Line Take consideration of the process flow, layout, power supply and distribution, and water supply of the clinker production lines, by utilizing the heat resource exhausted from the pre heater and cooler, one 7500kw pure low temperature waste heat power station is appropriate for the 2*2500t/d clinker production line.
Waste heat resource The waste heat source of the cement line can be utilized as follows: 2*2500t/d cement production lines kiln outlet cooler waste heat condition after reformation will be 2*65000Nm3/h-350℃. The waste gas will be introduced into the kiln outlet waste heat boiler(AQC boiler) for power generation; Outlet waste gas of the AQC boiler will be introduced into the existing kiln outlet EP. Kiln inlet five-stage pre heater waste gas condition will be 2*150000Nm3/h-340℃ The waste gas will be introduced into the kiln inlet waste heat boiler (SP boiler) for power generation and the exhausted gas temperature should be higher than 220℃for raw mill or coal mill drying.
2 Power supply and connection system solution At the beginning of the power station putting into production, 300~500kw start-up power supply is necessary which will be supplied by the general substation. After the generation putting into production, the generator will be connected to outside power network by general substation 6(10) kV. The power station and the existing system will be connected to the outside power network, but not feed power to it. The power consumption of the station will be supplied general substation or generator. In order to make sure the power station run in reason and smoothly, a high & low voltage distribution room should be plotted on the side of the main building. As the waste heat power station of the company, the generation power should be fed to the cement production line. The power station and the existing system will be connected to outside power network, but not feed power to it. Connection synchronous points will be set at generation liaison switch and generator outlet switch.
3. Water supply Since the average production and domestic water consumption will be about 1800m3/d, the water supply capacity should be 2200m3/d.
Technical safeguard condition Thermodynamic system According to the process flow and design parameter of 2*2500t/d cement production lines, adopting China institutes and manufacturers pure low temperature waste heat recovery technique and Chinese made equipments, the power generation amount per ton clinker can achieve 36~38kwh.. Brief introduction of technical solution Two kiln outlet waste heat boilers-AQC boilers The AQC boiler is arranged between cooler middle stage and the existing kiln outlet EP. The heat-receiving surface of the AQC boiler is divided into two stages: the first stage produces steam, and the second stage produces hot water. The saturation water of 135℃ will be feed to the AQC boiler steam stage and kiln inlet waste heat boiler(hereinafter called SP boiler); 1.6 MPa superheated steam produced in AQC boiler steam stage and SP boiler merges together and is introduced to a turbine for power generation. Condensing water of the turbine is pumped to AQC boiler hot water stage..
Two kiln inlet waste heat boilers-SP boilers The SP boiler is at the outlet of pre heater. The superheated steam produced in SP boiler and AQC boiler steam stage merges together and is introduced to a turbine foe power generation.
One condensing steam turbine is adopted to match the low temperature waste heat power station A Chinese-made condensing steam turbine is adopted, rated power is 4500kw, and initial steam parameter is 1.27Mpa-290℃
One generator os selected to match the condensing turbine One normal 6(10)kv AC generator with 7500kw rated power is adopted, which will be connected to outside power network by general substation 6(10)kv.
Circulation cooling water system will be adopted for meeting the cooling water demand of the power station. 4.2.6A”Filter+ demineralizing” system is adopted as chemical water treatment for meeting the boiler water criterion. DCS computer control system is adopted for monitoring the power station sunning.
4.3 Main equipment
Main technical economy index
The Technical Solution Of Pure Low Temperature Waste Heat Power Generation station For 5000t/d Cement Production Line Take consideration of the process flow, layout, power supply and distribution, and water supply of the clinker production line, by utilizing the heat resource exhausted from the pre heater and cooler, one 9000kw pure low temperature waste heat power station is appropriate for the 5000t/d clinker production line.
Waste heat resource The waste heat source of the cement line can be utilized as follows: 5000t/d cement production line kiln outlet cooler waste heat condition after reformation will be 240000Nm3/h-360℃. The waste gas will be introduced into the kiln outlet waste heat boiler(AQC boiler) for power generation; outlet waste gas of the AQC boiler will be introduced into the existing kiln outlet EP. Kiln inlet five-stage pre heater waste gas condition will be 340000Nm3/h-350℃. The waste gas will be introduced into the kiln inlet waste heat boiler (SP boiler) for power generation and the exhausted gas temperature should be higher than 220℃ for raw mile or coal mill drying.
Power supply and connection system solution At the beginning of the power station putting into production, 600~700kw start-up power station is necessary which will be supplied by the general substation. After the generator putting into production, the generator will be connected to outside power network by general substation 6(10) kV. The power station and the existing system will be connected to the outside power network, but not feet power to it. The power consumption of the station will be supplied by general substation or generator. In order to make sure the power station run in reason and smoothly, a high & low voltage distribution room should be plotted on the side of the main building. As the waste heat power station of the company, the generation power should be fed to the cement production line. The power station and the existing system will be connected to our outside power network but not feed power to it. Connection synchronous points will be set at generator liaison switch and generator outlet switch.
Water supply Since the average production and domestic water consumption will be about 1700m3/d, the water supply capacity should be 2000m3/d.
Technical safeguard condition Thermodynamic system According to the process flow and design parameter of 5000t/d cement production line, adopting China institutes and manufacturers pure low temperature waste heat recovery technique and Chinese-made equipments, the power generation amount per ton clinker can achieve 36~38kwh.
Brief introduction of technical solution Kiln outlet waste heat boiler-AQC boiler The AQC boiler is arranged between cooler middle stage and the existing kiln outlet EP. The heat-receiving surface of the AQC boiler is divided into two stages: the first stage produces steam, and the second stage produces hot water. The saturation water of 135℃ will be feed to the AQC boiler steam stage and kiln inlet waste heat boiler(hereinafter called SP boiler); 1.6MPa superheated steam produced in AQC boiler steam stage and SP boiler together and is introduced to a turbine for power generation. Condensing water of the turbine is pumped to AQC boiler hot water stage.
Kiln inlet waste heat boiler-SP boiler The SP boiler is at the outlet of pre heater. The superheated steam produced is SP boiler and AQC boiler steam stage merges together and is introduced to a turbine for power generation.
One condensing steam turbine is adopted to match the low temperature waste heat power station A Chinese-made condensing steam turbine is adopted, rated power is 9000kw, and initial steam parameter is 1.27MPa-290℃.
One generator is selected to match the condensing turbine One normal 6(10)kv AC generator with 9000kw rated power is adopted, which will be connected to outside power network by general substation 6(10) kV.
Circulation cooling water system will be adopted for meeting the cooling water demand of the power station. A“Filter+ demineralizing” system is adopted as chemical water treatment for meeting the boiler water criterion. DCS computer control system is adopted for monitoring the power station running.
Main equipment
Main technical economy index
The technical Solution Of Pure Low Temperature Waste Heat Power Generation station For 2*5000t/d Cement Production Line Take consider of the process flow, layout, power supply and distribution, and water supply of the clinker production line, by utilizing the heat resource exhausted from the pre heater and cooler, one 18000kw pure low temperature waste heat power station is appropriate for the 2*5000t/d clinker production line.
Waste heat resource The waste heat source of the cement line can be utilized as follows: 2*5000t/d cement production line kiln outlet cooler waste heat condition after reformation will be 2*240000Nm3/h-360℃. The waste gas will be introduced into the kiln outlet waste heat boiler (AQC boiler) for power generation; Outlet waste gas of the AQC boiler will be introduced into the existing kiln outlet EP. Kiln inlet five-stage pre heater waste gas condition will be 2*340000Nm3/h-350℃. The waste gas will be introduced into the kiln inlet waste heat boiler(SP boiler) for power generation and the exhausted gas temperature should be higher than 220℃ for raw mill or coal mill drying.
2 Power supply and connection system solution At the beginning of the power station putting into production, 1200~1500kw start-up power supply is necessary which will be supplied by the general substation. After the generator putting into production, the generator will be connected to outside power network by genral substation 6(10)kv. The power station and the existing system will be connected to the outside power network, but not feed power to it. The power consumption of the station will be supplied by general substation or generator. In order to make sure the power station run in reason and smoothly, a high & low voltage distribute room should be plotted on the side of the main building. As the waste heat power station of the company, the generation power should be fed to the cement production line. The power station and the existing system will be connected to outside power network, but not power to it. Connection synchronous points will be set at generator liaison switch and generator outlet switch.
Water supply Since the average production and domestic water consumption will be about 3400m3/d, the water supply should be 4000m3/d.
4. Technical safeguard condition 4.1 Thermodynamic system According to the process flow and design parameter of 2*5000t/d cement production line, adopting China institutes and manufacturers pure low temperature waste heat recovery and Chinese-made equipments, the power generation amount pert ton can achieve 36~38kwh.
4.2 Brief introduction of technical solution 4.2.1 Kiln outlet waste heat boiler-AQC boiler The AQC boiler is arranged between cooler middle stage and the existing kiln outlet EP. The heat-receiving surface of the AQC boiler is divided into two stages: the first stage produces steam, and the second stage produces hot water. The saturation water of 135℃ will be feed to the AQC boiler steam stage and kiln inlet waste heat boiler(hereinafter called SP boiler); 1.6Pa superheated steam produced in AQC boiler steam stage and SP boiler merges together and is introduced to a turbine for power generation. Condensing water of the turbine is pumped to AQC boiler hot water stage.
4.2.2 Kiln inlet waste heat boiler-SP boiler The SP boiler is at the outlet of pre heater. The superheated steam produced in SP boiler and AQC boiler steam stage merges together and is introduced to a turbine for power generation.
4.2.3 One condensing steam turbine is adopted to match the low temperature waste heat power station A Chinese-made condensing steam turbine is adopted, rated power is 18000kw, and initial steam parameter is 1.27Mpa-290℃/
4.2.4 One generator is selected to match the condensing turbine One normal 6(10)kv AC generator with 9000kw rated power is adopted, which will be connected to outside power network by general substation 6(10)kv.
4.2.5 Circulation cooling water system will be adopted for meeting the cooling water demand of the power station. 4.2.6 A“Filter+ demineralizing”system will be adopted as chemical water treatment for meeting the boiler water criterion 4.2.7 DCS computer control system is adopted for monitoring the power station sunning.
4.3 Main equipments
Main technical economy index
7. Experience reference in China
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