电厂锅炉的热力学分析
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摘要
本文运用熵的理论对锅炉运行过程进行了分析,熵的概念出自物理学,但是随着科学技术的飞速发展,它的定义及应用已经超出了物理学的范畴。熵的性质,功能和作用,以及在其他学科的应用为讨论工业生产问题提供了理论的支撑。
众所周知,能源问题已是当今世界瞩目的重要课题,能源的短缺促使人们的节能意识迅速提高,除了认真研究和大力开发各种新的能源资料外,还把合理用能即节能工作放在了重要的地位,而做好耗能设备的节能工作显然是非常重要的。电站锅炉是火力发电厂的主要耗能设备,因此,对电站锅炉进行节能分析,具有十分重要的意义。
目前,热平衡方法被广泛应用于电站锅炉,但它只能从能量的数量方面分析能量的利用情况,熵分析法可以从能量的量和质两个方面分析能量的利用情况。与热平衡分析方法相比较,熵分析方法不但能反映电站锅炉的外部损失如排烟、散热等损失,而且能揭示能量转换利用过程的内部损失,即不可逆过程损失。此外,熵分析法还可以较为完善的分析电站锅炉中各受热面的能量利用情况。因此,采用熵分析方法可以更完善、更具体的衡量电站锅炉的热力学完善程度,准确的揭示系统中损失最大的环节或过程,为节约能源提供目标及对策。
本文运用热力学的相关理论,将具体工业生产系统(电站锅炉)作为对象,以工业生产产生的熵增为研究手段,揭示工业生产的能量利用情况,并对各种情况进行了比较,以熵增最少为目的,即提高能量的利用率,减少浪费和污染。并将工业生产系统与自然生态系统作为一个统一体系进行研究,以熵作为研究工业生产对环境产生的综合影响的评价指标和手段。
The thesis has analysed the process of industrial production by using the theory of entropy, the concept of entropy comes from physics., but with the rapid development of science and technology, the definition of entropy was beyond the scope of physics. The property, function and effect of entropy, as well as its uses in other subjects has provided the theoretic support for discussing the problem of industrial production.
As it is well known to us, the question of energy sources is a significant question for discussion that people all along focus attention upon, and energy crisis enhances people's energy-saving consciousness. We must put the reasonable use of energy on an important station, except to study and open up all kinds of new energy. It is highly important do energy-saving work of energy-consuming equipment. Boiler is a primary energy-consuming equipment in power plant. Therefore,exergy analysis of boiler in power plant has a significant meaning.
Presently, the method of heat balance is widely used in boiler in power plant, but it can only analyses the status of using energy from the quantity of energy, the method of entropy analysis to exactly open out the heat-using status of boiler comes into use, and it analyses the status of using energy from the quantity and quality of energy. Compared with the method of heat balance, the method of exergy analysis not only reflects external losses of boiler in power plant, for example, waste heat loss and external heat losses, but also opens out inner losses in the course of energy conversion, for instance, nonreversible losses. Furthermore the method of entropy analysis may perfectly analyse the status of using energy of all kinds of boiler surface. Accordingly, the method of exergy analysis may perfectly and concretely weigh perfect thermodynamic degree, and exactly open out the tache and process of maximal losses, and offer the object and countermeasure for saving energy.
This thesis used the thermodynamic theories, analyse the entropy increase of industry system (the boiler in power plant), revealed the state of energy use in industry production, as well as compared the different stations, this was aimed at making entropy increae minimum, so that, the utilization rate would be rased, and waste and pollution would be decreased. besides, this paper made a study on the entropy index of the synthetical effect of industrial production system.
众所周知,能源问题已是当今世界瞩目的重要课题,能源的短缺促使人们的节能意识迅速提高,除了认真研究和大力开发各种新的能源资料外,还把合理用能即节能工作放在了重要的地位,而做好耗能设备的节能工作显然是非常重要的。电站锅炉是火力发电厂的主要耗能设备,因此,对电站锅炉进行节能分析,具有十分重要的意义。
目前,热平衡方法被广泛应用于电站锅炉,但它只能从能量的数量方面分析能量的利用情况,熵分析法可以从能量的量和质两个方面分析能量的利用情况。与热平衡分析方法相比较,熵分析方法不但能反映电站锅炉的外部损失如排烟、散热等损失,而且能揭示能量转换利用过程的内部损失,即不可逆过程损失。此外,熵分析法还可以较为完善的分析电站锅炉中各受热面的能量利用情况。因此,采用熵分析方法可以更完善、更具体的衡量电站锅炉的热力学完善程度,准确的揭示系统中损失最大的环节或过程,为节约能源提供目标及对策。
本文运用热力学的相关理论,将具体工业生产系统(电站锅炉)作为对象,以工业生产产生的熵增为研究手段,揭示工业生产的能量利用情况,并对各种情况进行了比较,以熵增最少为目的,即提高能量的利用率,减少浪费和污染。并将工业生产系统与自然生态系统作为一个统一体系进行研究,以熵作为研究工业生产对环境产生的综合影响的评价指标和手段。
The thesis has analysed the process of industrial production by using the theory of entropy, the concept of entropy comes from physics., but with the rapid development of science and technology, the definition of entropy was beyond the scope of physics. The property, function and effect of entropy, as well as its uses in other subjects has provided the theoretic support for discussing the problem of industrial production.
As it is well known to us, the question of energy sources is a significant question for discussion that people all along focus attention upon, and energy crisis enhances people's energy-saving consciousness. We must put the reasonable use of energy on an important station, except to study and open up all kinds of new energy. It is highly important do energy-saving work of energy-consuming equipment. Boiler is a primary energy-consuming equipment in power plant. Therefore,exergy analysis of boiler in power plant has a significant meaning.
Presently, the method of heat balance is widely used in boiler in power plant, but it can only analyses the status of using energy from the quantity of energy, the method of entropy analysis to exactly open out the heat-using status of boiler comes into use, and it analyses the status of using energy from the quantity and quality of energy. Compared with the method of heat balance, the method of exergy analysis not only reflects external losses of boiler in power plant, for example, waste heat loss and external heat losses, but also opens out inner losses in the course of energy conversion, for instance, nonreversible losses. Furthermore the method of entropy analysis may perfectly analyse the status of using energy of all kinds of boiler surface. Accordingly, the method of exergy analysis may perfectly and concretely weigh perfect thermodynamic degree, and exactly open out the tache and process of maximal losses, and offer the object and countermeasure for saving energy.
This thesis used the thermodynamic theories, analyse the entropy increase of industry system (the boiler in power plant), revealed the state of energy use in industry production, as well as compared the different stations, this was aimed at making entropy increae minimum, so that, the utilization rate would be rased, and waste and pollution would be decreased. besides, this paper made a study on the entropy index of the synthetical effect of industrial production system.
引文
1.王承阳.工业生产过程的熵分析[J],材料与冶金学院学报,2006.3
2.张怀德.负熵在生态系统中的应用[J],聊城大学学报(自然科学版),2004.6,17(2)：106～107.
3.杨庆贤.简论熵和负熵与地球生态问题[J],林业经济问题,2001,21(1)62～64.
4.王承阳 自组织理论没有面临难题[J]全国能源与热工2004年度学会 2004
5. Bejan A. Entropy Generation in Heat and Fluid Flow[M]. New York:Wiley,1982.
6. Bejan, A. Entropy Generation Minimization. (M) New York:Wiley,1996.
7.楚海林 基于熵的工业生产环境影响[D] 西南交通大学 2005
8.李大鹏 孙丰瑞 韩仁余 王少明.对流换热熵产生应用湍流三层结构模型的求解.(A)
全国高等学校工程热物理研究会第六届学术会议论文集 武汉 199620-25.
9.吴双应 对流换热过程的热力学分析及应用[D]重庆大学2004.5
10. Bejan A. A Study of Entropy Generation in Fundamental Convective Heat Transfer[J].Heat Transfer,1979, (101):718-725.
11. Mukherjee P., Biswas G., Nag P. K. Second-Law Analysis of Heat Transfer in Swirling Flow Through a Cylindrical Duct[J]. Heat Transfer,1987.5(109):308-313,
12. San J. Y., Worek W. M., Lavan Z. Entropy Generation in Convective Heat Transfer and Isothermal Convective Mass Transfer[J]. Heat transfer,1987.8(109):647-651,
13. J. Y. San, W. M. Worek, Z. Lavan. Entropy Generation in Combined Heat and Mass Transfer. Int[J]. Heat Mass Transfer,1987,30 (7):1359-1369.
14. Carrington C. G, Sun I. F. Second law Analysis of Combined heat and Mass Transfer Phenomena[J]. Heat Mass Transfer,1991,34 (11):2767-2773.
15. Sun I. F., Carrington C. G Application of Non-equilibrium Thermodynamics in Second Law Analysis[J]. Energy Resource Technology,1991,33-39.
16. Nag P. K., Mukherjee P. Thermodynamics Optimization of Convective Heat Transfer Though a Duct with Constant Wall Temperature. Int. J. Heat Mass Transfer,1987,30(2): 401-405.
17.王承阳, 环境污染末端治理的热力学认识[J].冶金能源,2003,22(6)：52～54
18.李友荣,靳明聪,唐经文.恒热流时管内热进口段对流换热过程的热力学分析及性能评价[A].全国高等学校工程热物理研究会第四届学术会议论文集 杭州 1992.
19.吴双应 李友荣.考虑热进口段时管内对流换热过程的热力学分析[J], 电站系统工程.1997,13(1)：8-12.
20.李友荣 曾丹苓.恒壁温时管内进口段对流换热过程的热力学分析及性能评价[A].中国工程热物理学会工程热力学与能源利用学术会议论文集 武夷山 1996.
21.金岩 火力发电厂的熵分析[D]东北大学 2006.2
22.沈维道 蒋智敏 童钧耕 工程热力学 高等教育出版社[M] 2000.
23.金继红.物理化学 第一册 (第三版)[M],地质出版社 1990.
24.吴双应 李友荣 曾丹苓. 换热管传热过程的熵产分析[J]重庆大学学报(自然科学版).(24)：2.
25.徐志明 杨善让 陈钟颀.关于换热器熵产分析的商榷(一)[J],东北电力学报 1993 13(3)9-15.
26.陈宏芳 杜建华.高等工程热力学[M],清华大学版社 2003.1.
27.阎洪环.热力发电厂[M],中国电力出版社 1997,15-18.
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29.李大鹏 孙丰瑞 韩仁余.热交换器熵产生的评价[J],电站系统工程 1996,12(6)：5-8.
30. Poulikakos D., Bejan A. Fin Generation for Minimum Entropy Generation in Forced Convection (J), Heat Transfer,1982, (104)661-623.
31. Poulikakos D. Fin Generation for Minimum Entropy Generation [J], MS thesis, University of Colorado, Boulder.
32.陈维汉 钱壬章.基本对流换热过程熵产分析[J],华中理工大学学报 1989,17(1)：32-35.
33. Fowler A. J., Bejan A. Correlation of Optimal Sizes of Bodies with External Forced Convective Heat Transfer. Int. Commun. Heat Mass Transfer,1994,(21):7-27.
34. London A. L., Shah R. K. Costs of Irreversibilities in Heat Exchanger Design [J], Heat Transfer Engineering,1983.4 (2):59-73.
35.李大鹏 孙丰瑞 陈林根 蔡琪.两相流体输送管道中不可逆性分析[A]中国工程热物理学会工程热力学与能源利用学术会议论文集 宜昌 1995
36. Bejan A. Second Law Analysis in Heat Transfer. Energy [M],1980,5:721-732 37. Ouellette W. A., Bejan A. Conservation of Available Work (Exergy) by Using promoters of Swirl Flow in Forced Convection Heat Transfer. Energy,1980,5:587-596
38. Sarangi S., Chowdhury K. On the Generation of Entropy in a Counter flow Heat Exchanger. Cryogenics,1982, (2):63-65
39. Bejan A. General Criterion for Rating Heat Exchanger Performance. Int. J. Heat Mass Transfer [M],1978,(21)655-658
40. Sekulic D. P. The Second Law Quality of Energy Transformation in a Heat Exchanger [J], Heat Transfer,1990, (112)295-300
41.李大鹏 孙丰瑞.几种流动形式换热器基于逆流式换热器的热力学性能比较(J),电站系统工程1997(3)：8～14.
42. Sekulic Dusan P. Entropy Generation in a Heat Exchanger. Heat Transfer Engineering, 1986,7(1-2):83-88.
43.Bejan A. The Concept of Irreversibility in Heat Exchanger Design:Counter flow Heat Exchanger for Gas-to-Gas Applications[J], Heat Transfer,1971,99:374-380.
44.Aceves-Saborio S., Ranasinghe J., Reisted G.M. An Extention to the Irreversibility Minimization Analysis Applied to Heat Exchanger[J], Heat Transfer,1989,(111):29-36.
45吴双应,曾丹苓,李友荣.恒壁温时污垢对管内对流换热热力学性能影响的分析[J]化工学报2002,53(4)；407-411.
46.吴双应,曾丹苓,李友荣.恒热流时污垢对管内对流换热热力学性能影响的分析[J]热能动力工程,2001,16(5)；503-506.
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2.张怀德.负熵在生态系统中的应用[J],聊城大学学报(自然科学版),2004.6,17(2)：106～107.
3.杨庆贤.简论熵和负熵与地球生态问题[J],林业经济问题,2001,21(1)62～64.
4.王承阳 自组织理论没有面临难题[J]全国能源与热工2004年度学会 2004
5. Bejan A. Entropy Generation in Heat and Fluid Flow[M]. New York:Wiley,1982.
6. Bejan, A. Entropy Generation Minimization. (M) New York:Wiley,1996.
7.楚海林 基于熵的工业生产环境影响[D] 西南交通大学 2005
8.李大鹏 孙丰瑞 韩仁余 王少明.对流换热熵产生应用湍流三层结构模型的求解.(A)
全国高等学校工程热物理研究会第六届学术会议论文集 武汉 199620-25.
9.吴双应 对流换热过程的热力学分析及应用[D]重庆大学2004.5
10. Bejan A. A Study of Entropy Generation in Fundamental Convective Heat Transfer[J].Heat Transfer,1979, (101):718-725.
11. Mukherjee P., Biswas G., Nag P. K. Second-Law Analysis of Heat Transfer in Swirling Flow Through a Cylindrical Duct[J]. Heat Transfer,1987.5(109):308-313,
12. San J. Y., Worek W. M., Lavan Z. Entropy Generation in Convective Heat Transfer and Isothermal Convective Mass Transfer[J]. Heat transfer,1987.8(109):647-651,
13. J. Y. San, W. M. Worek, Z. Lavan. Entropy Generation in Combined Heat and Mass Transfer. Int[J]. Heat Mass Transfer,1987,30 (7):1359-1369.
14. Carrington C. G, Sun I. F. Second law Analysis of Combined heat and Mass Transfer Phenomena[J]. Heat Mass Transfer,1991,34 (11):2767-2773.
15. Sun I. F., Carrington C. G Application of Non-equilibrium Thermodynamics in Second Law Analysis[J]. Energy Resource Technology,1991,33-39.
16. Nag P. K., Mukherjee P. Thermodynamics Optimization of Convective Heat Transfer Though a Duct with Constant Wall Temperature. Int. J. Heat Mass Transfer,1987,30(2): 401-405.
17.王承阳, 环境污染末端治理的热力学认识[J].冶金能源,2003,22(6)：52～54
18.李友荣,靳明聪,唐经文.恒热流时管内热进口段对流换热过程的热力学分析及性能评价[A].全国高等学校工程热物理研究会第四届学术会议论文集 杭州 1992.
19.吴双应 李友荣.考虑热进口段时管内对流换热过程的热力学分析[J], 电站系统工程.1997,13(1)：8-12.
20.李友荣 曾丹苓.恒壁温时管内进口段对流换热过程的热力学分析及性能评价[A].中国工程热物理学会工程热力学与能源利用学术会议论文集 武夷山 1996.
21.金岩 火力发电厂的熵分析[D]东北大学 2006.2
22.沈维道 蒋智敏 童钧耕 工程热力学 高等教育出版社[M] 2000.
23.金继红.物理化学 第一册 (第三版)[M],地质出版社 1990.
24.吴双应 李友荣 曾丹苓. 换热管传热过程的熵产分析[J]重庆大学学报(自然科学版).(24)：2.
25.徐志明 杨善让 陈钟颀.关于换热器熵产分析的商榷(一)[J],东北电力学报 1993 13(3)9-15.
26.陈宏芳 杜建华.高等工程热力学[M],清华大学版社 2003.1.
27.阎洪环.热力发电厂[M],中国电力出版社 1997,15-18.
28.李大鹏 孙丰瑞 韩仁余.管内强迫湍流换热熵产分析[A] 全国高等学校工程热物理研究会第四届学术会议论文集 武汉 1996.
29.李大鹏 孙丰瑞 韩仁余.热交换器熵产生的评价[J],电站系统工程 1996,12(6)：5-8.
30. Poulikakos D., Bejan A. Fin Generation for Minimum Entropy Generation in Forced Convection (J), Heat Transfer,1982, (104)661-623.
31. Poulikakos D. Fin Generation for Minimum Entropy Generation [J], MS thesis, University of Colorado, Boulder.
32.陈维汉 钱壬章.基本对流换热过程熵产分析[J],华中理工大学学报 1989,17(1)：32-35.
33. Fowler A. J., Bejan A. Correlation of Optimal Sizes of Bodies with External Forced Convective Heat Transfer. Int. Commun. Heat Mass Transfer,1994,(21):7-27.
34. London A. L., Shah R. K. Costs of Irreversibilities in Heat Exchanger Design [J], Heat Transfer Engineering,1983.4 (2):59-73.
35.李大鹏 孙丰瑞 陈林根 蔡琪.两相流体输送管道中不可逆性分析[A]中国工程热物理学会工程热力学与能源利用学术会议论文集 宜昌 1995
36. Bejan A. Second Law Analysis in Heat Transfer. Energy [M],1980,5:721-732 37. Ouellette W. A., Bejan A. Conservation of Available Work (Exergy) by Using promoters of Swirl Flow in Forced Convection Heat Transfer. Energy,1980,5:587-596
38. Sarangi S., Chowdhury K. On the Generation of Entropy in a Counter flow Heat Exchanger. Cryogenics,1982, (2):63-65
39. Bejan A. General Criterion for Rating Heat Exchanger Performance. Int. J. Heat Mass Transfer [M],1978,(21)655-658
40. Sekulic D. P. The Second Law Quality of Energy Transformation in a Heat Exchanger [J], Heat Transfer,1990, (112)295-300
41.李大鹏 孙丰瑞.几种流动形式换热器基于逆流式换热器的热力学性能比较(J),电站系统工程1997(3)：8～14.
42. Sekulic Dusan P. Entropy Generation in a Heat Exchanger. Heat Transfer Engineering, 1986,7(1-2):83-88.
43.Bejan A. The Concept of Irreversibility in Heat Exchanger Design:Counter flow Heat Exchanger for Gas-to-Gas Applications[J], Heat Transfer,1971,99:374-380.
44.Aceves-Saborio S., Ranasinghe J., Reisted G.M. An Extention to the Irreversibility Minimization Analysis Applied to Heat Exchanger[J], Heat Transfer,1989,(111):29-36.
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