基于再热器再循环冷却技术的高压供汽方案探讨  

Discussions on high pressure steam supply scheme based on reheater recirculation cooling technology

作　　者：杜旭 叶明星 王晨 张攀[3] DU Xu;YE Mingxing;WANG Chen;ZHANG Pan(Beijing Tianrui Teda Electric Power Engineering Co.,Ltd.,Beijing 101200,China;Guoneng Hebei Cangdong Power Generation Co.,Ltd.,Cangzhou 061113,China;Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Tsinghua University,Beijing 100084,China)

机构地区：[1]北京天瑞泰达电力工程有限公司,北京101200 [2]国能河北沧东发电有限责任公司,河北沧州061113 [3]清华大学热科学与动力工程教育部重点实验室,北京100084

出　　处：《热力发电》2024年第11期139-146,共8页Thermal Power Generation

摘　　要：在火电机组深度调峰成为常态化运行的前提下,对机组工业供汽的改造提出了更高的挑战。针对660 MW超临界机组高压供汽改造需求,提出以再热器再循环冷却技术为核心的3种供汽方案,并通过变工况热力计算分析方案的可行性及经济性。计算结果表明:30%及以上额定发电负荷在满足单机200 t/h、6.0 MPa、480℃供汽需求时,3种方案均可保证再热器在不超温的工况下安全运行,大幅提高机组宽负荷高压供汽能力;为了避免再热器出口流速超速,还需中调门配合参调运行,通过提高再热蒸汽压力以降低再热蒸汽流速;随着负荷的降低,满足额定供汽流量下的再热器再循环流量就会增加,方案1和方案3全工况下再循环流量相差不大,而方案2的高低负荷下再循环流量的比值可达5倍以上;3种供汽改造方案,方案2最节能,方案3次之,3种方案每年可分别产生3951、4445、4178万元的经济效益,但在实施过程中,对方案的选取要综合考虑投资成本、运行维护量及节能收益等因素。Under the premise that deep peaking of thermal power units has become normal operation,it poses a higher challenge to transformation of industrial steam supply of thermal power units.Three steam supply schemes using reheater recirculation cooling as the core technology are proposed to meet the requirements of high-pressure steam supply transformation of 660 MW supercritical units.Moreover,the feasibility and economy of these schemes are analyzed by thermodynamic calculation under varying working conditions.The calculation results show that,all the three schemes can ensure the safe operation of the reheater under non-overtemperature conditions,and greatly improve the wide load high pressure steam supply capacity of the unit at 30%rated power load or above and under conditions that meet the demand of single unit with 200 t/h,6.0 MPa and 480℃steam supply.In order to avoid overspeed of the flow rate at the reheater outlet,it is necessary to coordinate the operation of the immediate pressure(IP)control valve to reduce the flow rate of the reheated steam by increasing the pressure of the reheated steam.With the decrease of the load,the reheater recirculation flow rate under the rated steam supply flow rate will increase.The recirculation flow rate under the whole working conditions of scheme 1 and scheme 3 is not much different,and the ratio of the recirculation flow rate under the high and low load of scheme 2 can reach more than 5 times.Among the three steam supply transformation schemes,scheme 2 is the most energy efficient,scheme 3 is second,and the three schemes can produce economic benefits of 39.51,44.45 and 41.78 million yuan each year,but in the implementation process,the selection of schemes should consider factors such as investment cost,operation and maintenance amount and energy saving income.

关 键 词：高压供汽 再热器再循环 减温减压 蒸汽喷射器 背压机 

分 类 号：TM621[电气工程—电力系统及自动化]