燃煤电厂循环水回水系统扩大单元制运行研究与应用
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摘要
自然通风冷却塔出水温度高于设计值,会严重影响机组经济性。为解决河源电厂这一问题,从减少进入冷却塔循环水量入手,结合机组调停备用次数增多,单机运行时间增长的现状,论证并实施了循环水回水系统扩大单元制改造,将循环水分流到2座冷却塔进行换热降温。实验结果表明,循环水回水系统扩大单元制运行后,进入单个冷却塔的水量显著降低,循环水系统运行安全可控;在各典型工况下,凝汽器背压下降0.42～0.96 kPa不等,机组负荷越高,循环水量越大,凝汽器背压下降幅度越明显,因而显著提高了机组运行的经济性。
Higher than designed water temperature at the outlet of the natural draft cooling tower will seriously affect the economic efficiency of the unit. In order to solve such problem in Heyuan power plant, the amount of circulating water into the cooling tower was first reduced. Then by taking account of the current situation of more frequent standby dispatch whereas more hours of operation for a single unit, this paper demonstrates and implements the expanded unit system transformation of the circulating water drainage system, in which the circulating water were diverted to two cooling towers for heat exchange and cooling. The experimental results show that the amount of water entering each cooling tower decreases significantly while the operation of the circulating water system is still safe and controllable after the expansion of the unit operation of the recirculating water drainage system. Under various typical operating conditions, the condenser back pressure decreases by 0.42～0.96 kPa. Particularly, the higher the unit load, the more the circulating water volume and the more significantly the condenser back pressure decreases. Therefore, the economy of the unit operation is greatly improved.
Higher than designed water temperature at the outlet of the natural draft cooling tower will seriously affect the economic efficiency of the unit. In order to solve such problem in Heyuan power plant, the amount of circulating water into the cooling tower was first reduced. Then by taking account of the current situation of more frequent standby dispatch whereas more hours of operation for a single unit, this paper demonstrates and implements the expanded unit system transformation of the circulating water drainage system, in which the circulating water were diverted to two cooling towers for heat exchange and cooling. The experimental results show that the amount of water entering each cooling tower decreases significantly while the operation of the circulating water system is still safe and controllable after the expansion of the unit operation of the recirculating water drainage system. Under various typical operating conditions, the condenser back pressure decreases by 0.42～0.96 kPa. Particularly, the higher the unit load, the more the circulating water volume and the more significantly the condenser back pressure decreases. Therefore, the economy of the unit operation is greatly improved.
引文
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[16]张荣欣.自然通风冷却塔填料“非等高布置”的试验研究[C]//2016年清洁高效发电技术协作网年会.南京,2016.
[17]周昊,郝红亮.600MW火电机组冷却塔加装进风导流装置的设计与实践[J].电力科学与工程,2012,28(1):55-58.ZHOU Hao,HAO Hongliang.Design and experience of installing guide plate at cooling tower air-inlet of 600 MW unit[J].Electric Power Science and Engineering,2012,28(1):55-58.
[18]戴振会,孙奉仲,王宏国,等.冷却塔进风口加装导风板后的冷却性能比较与评价[J].中国电力,2009,42(10):24-27.DAI Zhenhui,SUN Fengzhong,WANG Hongguo,et al.Performance evaluation and its comparison of cooling towers before and after the installation of air deflectors[J].Electric Power,2009,42(10):24-27.
[19]电力行业电力规划设计标准化技术委员会.火力发电厂水工设计规范:DL/T 5339-2006[S].2006.
[20]张维佳.水力学[M].2版.北京:中国建筑工业出版社,2015.
[2]周兰欣,金童,尹建兴,等.火电机组湿式冷却塔加装导流板的数值研究[J].汽轮机技术,2010,52(1):13-16.ZHOU Lanxin,JIN Tong,YIN Jianxing,et al.Numerical study on wet cooling tower with baffle plates in thermal power generating units[J].Turbine Technology,2010,52(1):13-16.
[3]中国电力投资集团公司.600MW火电机组节能对标指导手册[M].北京:中国电力出版社,2008.
[4]张翠娇.塔型参数对于大型冷却塔热力特性影响的数值计算研究[D].济南:山东大学,2014.
[5]赵元宾,杨志,高明,等.填料非均匀布置对大型冷却塔冷却性能的影响[J].中国电机工程学报,2013,33(20):96-103.ZHAO Yuanbin,YANG Zhi,GAO Ming,et al.Impact of fill nonuniform layout on cooling performance of large-scale cooling towers[J].Proceedings of the CSEE,2013,33(20):96-103.
[6]黄凯.冷却塔淋水填料特性及结构优化实验研究[D].上海:东华大学,2014.
[7]胡三季,陈玉玲,刘廷祥,等.逆流式冷却塔不同高度的PVC淋水填料热力及阻力性能试验研究[J].吉林电力,2003,8(4):9-11.HU Sanji,CHEN Yuling,LIU Tingxiang,et al.Experimental investigation of thermodynamic and resistance performance about different heights PVC transfer packing in counter-flow cooling tower[J].Jilin Electric Power,2003,8(4):9-11.
[8]高明,王妮妮,史月涛,等.自然通风湿式冷却塔冷却数随外界侧风变化规律的研究[J].中国电机工程学报,2012,32(17):20-24.GAO Ming,WANG Nini,SHI Yuetao,et al.Research on change rules of merkel number for natural draft wet cooling tower with environmental cross wind with environmental cross wind[J].Proceedings of the CSEE,2012,32(17):20-24.
[9]CHEN Youliang,SUN Fengzhong,WANG Hongguo,et al.Experimental research of the cross walls effect on the thermal performance of wet cooling towers under crosswind conditions[J].Applied Thermal Engineering,2011,31:4007-4013.
[10]王冬.自然通风冷却塔冷却性能计算模型及影响因素[D].北京:华北电力大学,2007.
[11]刘剑涛,任建兴,杨涌文,等.环境侧风对300 MW火电机组冷却塔影响的数值模拟[J].汽轮机技术,2014,56(2):115-118.LIU Jiantao,REN Jianxing,YANG Yongwen,et al.Numerical simulation on effect of cross-wind to cooling tower of 300 MWthermal power unit[J].Turbine Technology,2014,56(2):115-118.
[12]Al-WAKED R,BEHNIAB M.Enhancing performance of wet cooling towers[J].Energy Conversion and Management,2007,48(10):2638-2648.
[13]余钢捷.广东河源电厂汽轮机冷端优化[R].武汉:中南电力设计院,2006.
[14]王玉宏,刘叶丽,孟岩.自然通风逆流式冷却塔效率低的原因分析及改造措施[J].河北电力技术,2007,26(5):40-42.WANG Yuhong,LIU Yeli,MENG Yan.Cause analysis and solutions on low-efficiency of natural ventilating counter current cooling tower[J].Hebei Electric Power,2007,26(5):40-42.
[15]赵海廷.大型冷却塔出水温度异常的原因及处理[J].发电设备,2007,21(4):294-296.ZHAO Haiting.A large cooling tower's abnormal outlet water temperature--cause&remedy[J].Power Equipment,2007,21(4):294-296.
[16]张荣欣.自然通风冷却塔填料“非等高布置”的试验研究[C]//2016年清洁高效发电技术协作网年会.南京,2016.
[17]周昊,郝红亮.600MW火电机组冷却塔加装进风导流装置的设计与实践[J].电力科学与工程,2012,28(1):55-58.ZHOU Hao,HAO Hongliang.Design and experience of installing guide plate at cooling tower air-inlet of 600 MW unit[J].Electric Power Science and Engineering,2012,28(1):55-58.
[18]戴振会,孙奉仲,王宏国,等.冷却塔进风口加装导风板后的冷却性能比较与评价[J].中国电力,2009,42(10):24-27.DAI Zhenhui,SUN Fengzhong,WANG Hongguo,et al.Performance evaluation and its comparison of cooling towers before and after the installation of air deflectors[J].Electric Power,2009,42(10):24-27.
[19]电力行业电力规划设计标准化技术委员会.火力发电厂水工设计规范:DL/T 5339-2006[S].2006.
[20]张维佳.水力学[M].2版.北京:中国建筑工业出版社,2015.