大型汽轮机组高背压供热改造适用性分析  

Applicability Analysis of High Back-pressure Heating Retrofit for Large-scale Steam Turbine Unit

作　　者：戈志华[1] 孙诗梦[1] 万燕[1] 赵世飞[1] 何坚忍[1] 

机构地区：[1]电站设备状态监测与控制教育部重点实验室(华北电力大学),北京市昌平区102206

出　　处：《中国电机工程学报》2017年第11期3216-3222,共7页Proceedings of the CSEE

基　　金：国家科技支撑计划项目(2014BAA06B01)~~

摘　　要：大型汽轮机组采用高背压余热供热,可减少传统抽汽供热造成的可用能损失,而且回收了排汽余热还可扩大机组的供热能力。以某330MW空冷机组为例,建立了高背压余热梯级供热系统理论模型,分析一次网回水温度变化对高背压供热机组性能的动态影响规律,获得了汽轮机组适于开展高背压供热改造的量化结果。结果表明一次网回水温度较低,供热面积较大地区适宜采用高背压供热方式;当回水温度高过59℃时,则不适宜采用高背压供热方式。和传统抽汽供热方式相比,高背压机组供热能力可扩大24.8%;当供热面积达到1000万m2时,发电标准煤耗率仅为138.7g/(kW·h),可有效缓解区域性用电用热矛盾。研究结果可为工程上供热模式的选取提供依据,避免高背压供热改造的盲目性。Large-scale steam turbine unit adopts high back-pressure heating method and hence can reduce the exergy losses of the extract steam, as well as extend the heating capacity of the unit due to utilization of exhaust heat. A theoretical model of cascade heating system with high back-pressure for 330MW air-cooled unit was established. The quantitative results of the application condition for heating retrofit were obtained by analyzing the dynamic effect of return water temperature of heating network on the performance of heating unit with high back-pressure. The results show that heating retrofit with high back-pressure is suitable for regions of low return water temperature and large heating area. When the return-temperature exceeds 59℃,the retrofit seems to be inappropriate. The heating capacity of the unit with high back-pressure is 24.8% higher than that of the traditional heating method using extraction steam. When the heating area reaches 10 million m2, the standard coal consumption rate is 138.7g/（kW·h）, which can effectively alleviate the contradiction between regional electricity and heat. The research provides the basis for selecting the heating mode and can avoid the aimlessness of utilizing heating retrofit with high back-pressure.

关 键 词：热电联产 高背压 供热改造 适用条件 热电比 

分 类 号：TK11[动力工程及工程热物理—热能工程]