Thermal Economic Analyses of a Power Unit Using Indirect Dry Cooling System With an Evaporative Cooler

doi:10.11930/j.issn.1004-9649.201706084

Abstract

Abstract: Indirect dry cooling systems are widely used in coal-fired power plants. However, high environmental temperatures affect the heat dissipation performance of the dry cooling tower, causing the increase of the back pressure of the steam turbine. In this work, the evaporative cooler operating with the dry cooling tower is adopted to reduce the circulating water temperature and the exhaust steam pressure, and improve the thermal efficiency of the power unit. Taking a 600-MW steam turbine unit as the study object, an indirect dry-cooled system with evaporative cooler is designed and a mathematical model is established. The matching characteristics of the heat load distribution between the evaporative cooler and the dry cooling tower are analyzed. The back pressure, the water consumption and the pump power consumption are analyzed for various heat loads. The results show that at the rated load, when the ratio of the water flow rate for the evaporative cooler to the total circulating water flow rate is between 0.21 and 0.31, and the generation standard coal consumption rate decreases by about 7.4 g/(kW·h).

Key words: indirect dry-cooled system, evaporative cooler, cooling tower, thermal economy

CLC Number:

TK264.1

ZOU Qingjiang, ZHANG Yijiang, GUO Minchen, CHU Dequan. Thermal Economic Analyses of a Power Unit Using Indirect Dry Cooling System With an Evaporative Cooler[J]. Electric Power, 2018, 51(1): 164-170.

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URL: https://www.electricpower.com.cn/EN/10.11930/j.issn.1004-9649.201706084

https://www.electricpower.com.cn/EN/Y2018/V51/I1/164

References

[1] 马义伟. 发电厂空冷技术的现状与进展[J]. 电力设备, 2006, 7(3): 5-7. MA Yiwei. Present status and prospect of utility air cooling technology [J]. Electrical Equipment, 2006, 7(3): 5-7.
[2] 余耀. 空冷机组高背压供热与抽汽供热的热经济性比较[J]. 中国电力, 2016, 49(9): 104-113. YU Yao. Thermal economics comparison between high back pressure heating and extraction heating for a direct air-cooled power unit [J]. Electric Power, 2016, 49(9): 104-113.
[3] 金升祥, 王清. 空冷机组混合冷却的综合应用及发展前景[J]. 中国电力, 2013, 46(6): 5-9. JING Shengxiang, WANG Qing. Comprehensive application and prospect of hybrid cooling for air-cooled units [J]. Electric Power, 2013, 46(6): 5-9.
[4] 杨志军. 极端气候环境下间接空冷发电机组的运行控制[J]. 中国电力, 2015, 48(1): 52-59. YANG Zhijun. Operation control of indirect air-cooling unit in extreme climate environment [J]. Electric Power, 2015, 48(1): 52-59.
[5] 梁振明, 王平. 国内首例 600 MW 机组间接空冷示范工程及技术[J]. 中国电力, 2010, 43(3): 31-34. LIANG Zhenming, WANG Ping. The first domestic indirect air-cooled demonstration project of 600 MW unit and its technology research [J]. Electric Power, 2010, 43(3): 31-34.
[6] 刘轶斌, 李利凯. 火电厂间接空冷系统度夏能力研究[J]. 能源与节能, 2011(8): 89-90. LIU Yibin, LI Likai. Capacity of summer spending investigation on indirect air-cooling system in thermal power plant[J]. Energy and Energy Conservation, 2011(8): 89-90.
[7] 田松峰, 刘会阳, 朱亚宁, 等. 喷雾增湿对间接空冷机组散热器影响的数值研究[J]. 汽轮机技术, 2015(1): 13-16. TIAN Songfeng, LIU Huiyang, ZHU Yaning, et al. Optimization study of spray humidification device by indirect air-cooled unit [J]. Turbine Technology, 2015(1): 13-16.
[8] REZAEI E, SHAFIEI S, ABDOLLAHNEZHAD A. Reducing water consumption of an industrial plant cooling unit using hybrid cooling tower [J]. Energy Conversion & Management, 2010, 51(2): 311-319.
[9] TANG T, XU J, JIN S, et al. Study on operating characteristics of power plant with dry and wet cooling systems [J]. Energy & Power Engineering, 2013, 5(4): 651-656.
[10] 蒋常建, 范云良, 杨强生. 蒸发式冷却器的传热传质试验研究[J]. 上海交通大学学报, 1999, 33(8): 1032-1035. JIANG Changjian, FAN Yunliang, YANG Qiangsheng. Experimental heat and mass transfer study of evaporative cooler[J]. Journal of Shanghai Jiao Tong University, 1999, 33(8): 1032-1035.
[11] 朱冬生, 涂爱民, 李元希, 等. 蒸发式冷却器/闭式冷却塔的应用前景及其设计计算[C]//中国制冷学会2007年学术年会, 杭州. 2007. ZHU Dongsheng, TU Aimin, LI Yuanxi, et al. Design and application prospect of evaporative cooler/closed-wet cooling tower[C]//Academic annual conference of China Refrigeration Association, Hangzhou. 2007.
[12] 郑伟业, 朱冬生, 宋进, 等. 闭式冷却塔的计算模拟[J]. 高校化学工程学报, 2012, 26(2): 216-221. ZHENG Weiye, ZHU Dongsheng, SONG Jin, et al. Simulation of closed wet cooling towers [J]. Journal of Chemical Engineering of Chinese Universities, 2012, 26(2): 216-221.
[13] 朱冬生, 钟振兴, 蒋翔, 等. 蒸发冷却节能技术在电站冷却系统中的应用研究[J]. 太原理工大学学报, 2010, 41(5): 581-584. ZHU Dongsheng, ZHONG Zhenxing, JIANG Xiang, et al. Application of evaporative cooling energy saving technology in power plant cooling system[J]. Journal of Taiyuan University of Technology, 2010, 41(5): 581-584.
[14] 张春雨, 严俊杰, 李秀云, 等. 哈蒙式间接空冷系统变工况特性的理论研究[J]. 动力工程学报, 2000, 20(1): 566-570. ZHANG Chunyu, YAN Junjie, LI Xiuyun, et al. Theoretical study on variable condition characteristics of Harmon type indirect air cooling system [J]. Power Engineering, 2000, 20(1): 566-570.
[15] 李勇, 曹祖庆. 凝汽器清洁率的概念及测试方法[J]. 汽轮机技术, 1995(2): 73-76. LI Yong, CAO Zuqing. Concept and testing method of condenser cleaning rate [J]. Turbine Technology, 1995(2): 73-76.
[16] 朱玉娜. 大型电站汽轮机的性能监测模型研究及应用[D]. 南京：东南大学, 1999. ZHU Yuna. Research and application of performance monitoring model for large scale power plant steam turbine[D]. Nanjing: Southeast University, 1999.
[17] 徐大懋, 柯严, 王世勇. 汽轮机功率背压特性的通用计算方法及其应用[J]. 热能动力工程, 2010, 25(6): 605-608. 请补充引用页码范围 XU Damao, KE Yan, WANG Shiyong. General calculation method and application of power back pressure characteristic of steam turbine [J]. Journal of Engineering for Thermal Energy and Power, 2010, 25(6): 605-608.
[18] 郭民臣, 王清照, 魏楠, 等. 电厂热力系统矩阵分析法的改进[J]. 热能动力工程, 1997, 12(2): 103-106. GUO Minchen, WANG Qingzhao, WEI Nan, et al. Improvement of matrix analysis method for thermal system of power plant [J]. Journal of Engineering for Thermal Energy and Power, 1997, 12(2): 103-106.
[19] 郭民臣, 王清照. 电厂热力系统的定功率方程与热效率[J]. 现代电力, 1997(2): 11-16. GUO Minchen, WANG Qingzhao. The constant power equation and efficiency for plant thermal system [J]. Modern Electric Power, 1997(2): 11-16.