加装低压省煤器对汽轮机排汽量的影响研究
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摘要
为研究低压省煤器吸收的排烟余热的有效利用水平,基于等效焓降法的基本原理,建立了汽轮机低压加热系统中凝结水抽出与引入对其排汽量影响的通用计算模型,进而推导出低压省煤器在各种连接方式下投入运行后对汽轮机排汽量影响的通用计算模型。以某国产330 MW机组为例,利用所提出的计算模型得出两种不同工况下汽轮机排汽量和排汽损失的增加值,结果表明,低压省煤器吸收的排烟余热能用于汽轮机做功的仅为10%左右,其余热量最终都进入冷源损失。
In order to evaluate the effectiveness of utilizing the heat absorbed by the low-pressure economizer, based on the fundamental principles of the equivalent enthalpy drop method, a general computation model is established for the influence of extraction and injection of the condensate in the low-pressure heating system on the exhaust volume of the steam turbine. Then, a general model is derived to compute the influence of the low-pressure economizer on the steam turbine exhaust volume when operated under various connection modes. Taking a domestic 330 MW unit as an example, using the computation model proposed in this paper, the increments of the steam exhaust volume and exhaust losses under two different operating conditions are obtained respectively, which shows that only about 10% of the thermal energy absorbed in the low-pressure economizer is reused by the steam turbine to produce power, while the rest of the heat eventually becomes part of cold source loss.
In order to evaluate the effectiveness of utilizing the heat absorbed by the low-pressure economizer, based on the fundamental principles of the equivalent enthalpy drop method, a general computation model is established for the influence of extraction and injection of the condensate in the low-pressure heating system on the exhaust volume of the steam turbine. Then, a general model is derived to compute the influence of the low-pressure economizer on the steam turbine exhaust volume when operated under various connection modes. Taking a domestic 330 MW unit as an example, using the computation model proposed in this paper, the increments of the steam exhaust volume and exhaust losses under two different operating conditions are obtained respectively, which shows that only about 10% of the thermal energy absorbed in the low-pressure economizer is reused by the steam turbine to produce power, while the rest of the heat eventually becomes part of cold source loss.
引文
[1]任彦,赵宁,陈晓峰.火力发电厂低压省煤器系统的节能效果研究[J].热能动力工程,2013, 28(4):372-375.REN Yan, ZHAO Ning, CHEN Xiaofeng. Study of the energy-saving effectiveness of a low pressure economizer system in a thermal power plant[J]. Journal of Engineering for Thermal Energy and Power, 2013, 28(4):372-375.
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[8]宋景慧,刘桂才,廖艳芬,等.燃煤机组锅炉低温烟气余热利用节能效益分析[J].热力发电,2015, 44(9):57-60.SONG Jinghui, LIU Guicai, LIAO Yanfen, et al. Energy-saving analysis for heat recovery from low-temperature flue gas in coal-fired units[J]. Thermal Power Generation, 2015, 44(9):57-60.
[9]温山,阎维平,常建刚,等.双级低压省煤器技术及其经济性分析[J].热力发电,2013, 42(2):7-11.WEN Shan, YAN Weiping, CHANG Jiangang, et al. Two-stage low pressure economizer technology and its economic analysis[J].Thermal Power Generation, 2013, 42(2):7-11.
[10]赵玉柱,庞乐,梁绪.基于能量损失的低压省煤器系统节能效果研究[J].热能动力工程,2017, 32(11):113-116.ZHAO Yuzhu, PANG Le, LIANG Xu. Study on the energy-saving effect of low-pressure economizer system based on energy loss[J].Journal of Engineering for Thermal Energy and Power, 2017, 32(11):113-116.
[11]庞乐.定功率条件下低压省煤器对机组热经济性的影响[J].热能动力工程,2016, 31(9):100-103.PANG Le. Influence of a low pressure economizer on the thermal cost-effectiveness of its unit at a constant power output[J]. Journal of Engineering for Thermal Energy and Power, 2016, 31(9):100-103.
[12]顾凯颖,张忠孝,胡广涛,等.低压省煤器传热特性的实验研究[J].电站系统工程,2014, 30(5):30-32.GU Kaiying, ZHANG Zhongxiao, HU Guangtao, et al. Research on heat transfer characteristics of low pressure economizer[J]. Power System Engineering, 2014, 30(5):30-32.
[2]常海青,张燕.锅炉烟气余热深度利用及减排技术的研究与应用[J].中国电力,2016,49(10):43-48.CHANG Haiqing, ZHANG Yan. Research and application of indepth boiler flue gas waste heat utilization and emission reduction technology[J]. Electric Power, 2016, 49(10):43-48.
[3]安恩科,马健越.加装低压省煤器对汽轮机相对内效率的影响[J].同济大学学报(自然科学版),2010, 38(10):1492-1495, 1500.AN Enke, MA Jianyue. Effect of low pressure economizer on relatively internal efficiency of steam turbine[J]. Journal of Tongji University(Natural Science), 2010,38(10):1492-1495, 1500.
[4]黄新元,孙奉仲,史月涛.火电厂热系统增设低压省煤器的节能效果[J].热力发电,2008, 37(3):56-58.HUANG Xinyuan, SUN Fengzhong, SHI Yuetao. Energy-saving effect of additionally installed low pressure economizer in thermodynamic system of thermal power plant[J]. Thermal Power Generation, 2008, 37(3):56-58.
[5]韩爽,王伟锋,张朋飞,等.加低装压省煤器机组节能效果分析[J].热力发电,2015, 44(12):133-135.HAN Shuang, WANG Weifeng, ZHANG Pengfei, et al. An analyzing example for unit energy-saving with low-pressure economizer[J]. Thermal Power Generation, 2015,44(12):133-135.
[6]张红方,王勇,田松峰,等.基于等效焓降法的低压省煤器系统经济性分析[J].节能技术,2011,29(5):457-461.ZHANG Hongfang, WANG Yong, TIAN Songfeng, et al. Economic analysis of low pressure economizer system based on the equivalent enthalpy drop method[J]. Energy Conservation Technology, 2011,29(5):457-461.
[7]李建锋,朱超,冷杰,等.降低锅炉排烟温度的2种方式比较[J].中国电力,2016, 49(10):43-48.LI Jianfeng, ZHU Chao, LENG Jie,et al. Comparison of two methods for reducing boiler exhaust flue gas temperature[J]. Electric Power, 2016, 49(10):43-48.
[8]宋景慧,刘桂才,廖艳芬,等.燃煤机组锅炉低温烟气余热利用节能效益分析[J].热力发电,2015, 44(9):57-60.SONG Jinghui, LIU Guicai, LIAO Yanfen, et al. Energy-saving analysis for heat recovery from low-temperature flue gas in coal-fired units[J]. Thermal Power Generation, 2015, 44(9):57-60.
[9]温山,阎维平,常建刚,等.双级低压省煤器技术及其经济性分析[J].热力发电,2013, 42(2):7-11.WEN Shan, YAN Weiping, CHANG Jiangang, et al. Two-stage low pressure economizer technology and its economic analysis[J].Thermal Power Generation, 2013, 42(2):7-11.
[10]赵玉柱,庞乐,梁绪.基于能量损失的低压省煤器系统节能效果研究[J].热能动力工程,2017, 32(11):113-116.ZHAO Yuzhu, PANG Le, LIANG Xu. Study on the energy-saving effect of low-pressure economizer system based on energy loss[J].Journal of Engineering for Thermal Energy and Power, 2017, 32(11):113-116.
[11]庞乐.定功率条件下低压省煤器对机组热经济性的影响[J].热能动力工程,2016, 31(9):100-103.PANG Le. Influence of a low pressure economizer on the thermal cost-effectiveness of its unit at a constant power output[J]. Journal of Engineering for Thermal Energy and Power, 2016, 31(9):100-103.
[12]顾凯颖,张忠孝,胡广涛,等.低压省煤器传热特性的实验研究[J].电站系统工程,2014, 30(5):30-32.GU Kaiying, ZHANG Zhongxiao, HU Guangtao, et al. Research on heat transfer characteristics of low pressure economizer[J]. Power System Engineering, 2014, 30(5):30-32.