Sparkplug Recycling Economy Boosting Construction of Conservation-minded Cement Industry |
| FROM： CREATEDATE：2009-02-03 |
2006 CHINA INTERNATIONAL CEMENT
TECHNOLOGY CONFERENCE
March 9-11, 2006 , Beijing , China
Yu Xingmin, Zhang Fu
Tianjin Cement Industry Design & Research Institute
Name Yu Xingmin
Education level Bachlor
Title of technical post Prof. senior Engineer
Date of birth September 1955
Position President of Tianjin Cement Industry Design ＆ Research Institute
General overview
Yu Xingmin , born on September 1955, professional senior engineer, now is the president of Tianjin Cement Industry Design and Research Institute. He graduated from Ha erbin Building engineer institute where he majored in cement on February 1982. Then he worked in Tianjin Cement Industry Design and Research Institute, as technician, engineer, state room director, minister of project manage department, vice general engineer, vice president, president.
Sparkplug Recycling Economy, Boosting Construction of Conservation-minded Cement Industry
Yu Xing Min, Zhang Fu
Tianjin Cement Industry Design & Research Institute
1. Foreward
Nowadays China is in the period of economical sustainable development in high speed. It increasingly requires more and more sources and energy consumption. Limited by Chinese industrial level, and meanwhile, shortage of sources and energy, sources and energy wastes are serious problems existed.
Considering of the present deposits of our sources and energy, the shortages will be badly standout referring to the afterward economic and social development. How to make full and reasonable existing valuable sources is a critical subject to insure continuous economic development. Therefore, spark plug recycling economy, saving sources, improving environment conditions, raising up economic efficiency, optimizing sources and energy deploy is a long stratagem policy in national economy and social development.
In 16th NCCPC the developing stratagem of building up a conservation-minded and environmentally friendly society is clearly raised out, and for the first time taking it as the stratagem mission in national economy and social development. In suggestions of the 11th “five-year plan” that is already put at ever high position.
Energy shortage has already influence all fields’ production and development, especially in cement industry. Recent years, power and coal shortages have appeared all over China , many cement plants faced with difficulties of low running rate and economic efficiency due to lack of power and coal supply and the cost increasing. However, making full use of waste heat for generating electricity or power & heat driving can not only lower power consumption, saving energy in cement production, but also reduce the pollution, same as reducing sulphur dioxide release in fire power plant. This has been an efficient method to save energy and improve environment conditions at present.
TCDRI has been working on technical and equipment development in cement industry, and actively developing and utilizing technology in source integrate usages, energy saving, environmental protection. By the efforts of many generations, there is a great progress on technology level, equipment quality and energy saving in cement industry, especially the hard working on pushing the cement industry transform to source saving, and amity environment enterprises, at the same time, TCDRI has proprietary intellectual property rights, and made low-temperature heat generating electricity technology and machinery to reliable gradually.
2. Waste Heat Recovery Power Generation
Regarding to the resource comprehensive utilization electricity by subsidiary device, the specialty is no more additional burning device, only adopt waste heat from the cement kiln to generate electricity. So that there is no more gas, fly-ash and slag release point, for getting efficient energy saving and better environmental protection.
Due to ex-low temp. heat coming from the kiln head and end, to generate electricity requires special equipment and technical system. For getting to the goal, after fully learned and studied foreign relative technical system and performance of rolling gas input steam engine, TCDRI co-operate with domestic steam engine manufacturers and for the first time in the history fabricated the first set 4500kw rolling gas input (bi-pressure) steam engine in 1999, and put it into production successfully. Its mechanical structure and parameter fill in the blank technically in domestic steam engine manufacturing history. The success has made a solid foundation for localization technically and mechanically by using ex-low temperature heat generate electricity in cement industry.
Based on it, TCDRI has proprietary intellectual property rights, totally local produced waste heat recovery power generation technology and process, after analysing Ningguo Cement Plant and Liuzhou Cement Plant related experience, summarizing theories while executing the two engineering by using subsidiaryr boiler.
In May 2002, TCDRI contracted Shanghai Wan’an Company’s technical consultation and engineering design for such generating electricity in a 1350t/d 4-stage preheater cement production line. It used TCDRI technology and domestic machinery. The engineering started in September 2002 ， and completed in May 2003, installed capacity 2500kw, designed capacity 1900kw, actual capacity 1900kw to 2100kw, unit capacity of 34 to 37 kw/ t clinker, which close to same international level. By two years running in production, key equipment and system works as well, all economical parameters reaches targets, or even better than the designed targets.
For this, waste heat recovery power generation of 4-stage preheater cement production lines with capacity of 4000t/d in Anhui Ningguo, 3600 t/d Guangzhou Liuzhou, 1350 t/d in Shanghai Wan’an has set up an example in cement industry with this specific technology and equipment.
Following up this innovation, TCDRI, summarize the experience before, successfully developed the similar system technology and equipment but for 5-stage preheater cement production line after further study and research technically.
In March 2005, the power station designed by TCDIR on 5-stage preheater cement production of Zhejiang Shenhe put into production, with installed power 3000kw, designed generated energy 2500kw, actually 2800 to 2900 kw, above 27 kw/ton clinker. It indicates such kind of power station on 5-stage preheater of 2500 t/d is successfully in operation for the first time in the history.
From July to Sept. 2005, after further modification technically, TCDRI adopted local equipment to install two power stations on 5000 t/d cement plant with 5-stage preheater in Jiangsu Meishang and Zhejian Sanshi, generating capacity 6500 kw to 6600kw each, above 30 kw/ton clinker. It indicates such kind of power station on 5-stage preheater of 5000 t/d is successfully in operation for the first time in the history.
By the end of 2005, the reference of TCDRI’s ex-low temperature generating power stations are: 2 stations on 5-stage preheater, with capacity of 5000 t/d cement line each; 5 stations on 5-stage preheater, with capacity of 2500 t/d cement line each; 1 stations on 5-stage preheater, with capacity of 1200 t/d cement line each.
In 2006, after optimizing design and system data, TCDRI is carrying out and putting into operation of more than 10 ex-low temperature heat generating power stations with the third technology of higher technical and machinery level, unit capacity can go up to 35 kwh/ton clinker.
3. System Matching in Waste Heat Recovery Power Station
Since the differences of heat quality and quantity caused by variety of cement production capacity under the restriction of cement production process, materials, difference types of key equipment, specific local climate conditions, waste heat power stations should have different scale, different data, machinery specification, although the basic theoretical generating technology is almost the same.
3.1 System selection on waste heat power station for 4-stage preheater
Shanghai Wan ’ an Cement Production Line with capacity of 1350 t/d by 4-stage preheater: Outlet ex-heat quantity of preheater and cooler are 95,000Nm3/h, 360 to 390 ℃ , and 94,000Nm3/h, 240 ℃ .
To the specific conditions and local equipment specification, the system and key machinery are as follows:
(Bi-pressure) replenishing gas condensing steam turbine, installed power 2500kw. Steam sources for generating come from waste heat boilers of kiln feeding and kiln head, and the saturation replenishing steam at kiln head. This way can reasonably manage the heat power system and key equipment at the time of fully recollecting and using the waste heat at kiln heat;
The special design on SP boiler are as vertical settings, mechanical shaking, circulating naturally. The whole boiler is continuous shaking, so dust cleaning is even. The efficient dust hopper can avoid motor stops when high density of dust in sudden, for this cement production will not be interrupted. The most standout in the boiler is to have natural circulating, which replace two sets hot water circulating pumps, lowing operation cost, making the system more reliable. Vertical structure requires less space, making easy in-out piping settings.
AQC waste heat boiler is vertical and natural circulating structure: no dust cleaning devices due to less sticky dust from cooler. Meanwhile, wing shape screw pipes for heat exchange enlarges efficient area, lowing boiler volume, and its cost as well. In front of the AQC boiler the 1st generation high efficient sedimentation system reduces the AQC worn out by exhausted gas.
Proper modification to grate cooler, such as setting a gas drawing gate for gas releasing in the middle of AQC, the quantity will be adjusted by cooler gas valve, to insure the gas temperature being above 350 ℃ . The data will be 40,000Nm3/h, 350 to 400 ℃ .
The whole power generating station installed up-date DCS control system developed by TDCRI, which is reliable, whole view indication, record, alarm, and protection programme.
Two sets waste heat boiler installed with extra in-out piping system, that can insure cement production line running normally when urgency occurred.
3.2 System arrangement in waste heat power generating station on 5-stage preheater
TCDRI made the following system arranging and key equipment selection based on specific power generating technology and local fabricated machinery:
Steam turbine is of condensing gas (single pressure), with 6000kw installed power ， generating power is the waste heat coming from the boilers installed at kiln end and head. This system simplifies the heating arrangement, making full use of the collected exhausted heat, reducing engineering costs. The steam turbine, installed modern 505 digital adjusting system, makes easy start-up, shut-down and proper running. Central oil system is concentrative, better for mounting and checking. After over half year in operation, key equipment and system has been running properly.
Special points on SP ex-heat boiler: vertical settings, casing style, mechanical shaking, natural circulation. Casing style speeds up installation, avoiding gas leakage. Continuous shaking makes even cleaning. The efficient dust hopper can avoid motor stops when high density of dust in sudden. Natural circulating replaces two sets hot water circulating pumps, lowing operation cost, making the system more reliable.
AQC ex-heat boiler is also vertical, natural circulating structure. Since dust from cooler is not sticky, so there is no dust cleaning devices. Wing screw piping for heat exchange increases exchanging area, squeezed boiler volume, reducing boiler worn out, and meanwhile, lowing down gas resistance and temperature loss.
All cooler gas to AQC not only avoids cooler’s modification itself, but also increases waste heat collecting efficiency, shortening engineering construction period and kiln shut-down time.
The whole power generating system is installed with DCS control system developed by TCDRI independently, which is simple, reliable, visible, recordable, alarming, so to make the programme more perfect and power generating system more stable.
4. The key technical and economic index of waste heat power generating station on 5-stage preheater
Table 1 Key Index of Waste Heat Power Station for 2500 t/d Cement Production Line
No. Name Unit Index Note
1 Designed installed capacity MW 4.5
2 Generating power kW 3.4 ～ 3.8
3 Capacity/year 104kWh 2520
4 Capacity/H/ton clinker kWh/t 32 ～ 35
5 Average cost Yuan/kwh 0.08 ～ 0.12
6 Investment 10,000yuan 2800 ～ 3100
7 Payout period year 2.5 ～ 4
Table 2 Key Index of Waste Temperature Heat Power Station for 5000 T/d Cement Production Line
No. Name Unit Index Note
1 Designed installed capacity MW 7.5 或 9
2 Generating power kW 6.8 ～ 8.8
3 Capacity/year 104kWh 5400
4 Capacity/H/ton clinker kWh/t 32 ～ 35
5 Average cost Yuan/kwh 0.08 ～ 0.12
6 Investment 10,000yuan 4500 ～ 5200
7 Payout period year 2.5 ～ 3.5
If setting up waste heat power generating station together with dry process cement production line at the same time ， all can be considered as a whole package in the design, such as general layout, water supply and drainage, cooling system, water treatment and reclaimed water integrate usage; power generation, power distribution and its networks; cement process flow system, key equipment selection, exhausted heat reclaiming system; gas and water distribution layout; civil engineering, equipment installation, etc. All these not only can raise the reclaimed heat usage, but also low down the cost of exhausted heat power generating station, its economic efficiency is remarkable.
Summery
Power generating totally by exhausted gas from dry process cement production line, without any additional primary fuel, will be carried out by reclaiming the releasing heat, and meanwhile have no any pollution. It is positive to energy saving, reduce dust and CO2 releasing, lowing down greenhouse effect, protecting entironment.
Based on the index of dry process cement production and exhausted gas in China , by installing TCDRI’s 3rd waste heat recovery power generating station and local equipment, the power station capacity is 32 to 35 kwh/ton clinker. If power cost in the market is 0.50 Yuan/kwh, taking out electricity generating cost 0.10 Yuan/kwh, per ton clinker cost can deduct by 12 to 14 Yuan. Therefore, such power station can low down the cement production cost, strengthen the competitive ability in the market, rising up economic beneficiary.
Although electricity shortage is releasing gradually, the price will be higher steadily due to the fuel in short supply, high cost of reclaimed sources. So the state government encourages power generating projects by using claiming heat and pressure in industrial production for the purpose of energy shortage, and founding proper development basis.
Waste heat recovery power generating station can transfer heat to electricity, efficiently reduce engine consumption in cement production. And meanwhile, it will low down exhausted gas temperature, reduce pollution cause in cement production. So it must a very good foreground because of the economic efficiency and social beneficiary.
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