基于背压小汽轮机方案的大型燃煤电站供热改造  

Heating retrofit for large-scale coal-fired power stations based on small back-pressure turbine scheme

作　　者：李靖 陈海[1] 刘健[1] 魏运军[1] 程锋[1] 骆超[2] LI Jing;CHEN Hai;LIU Jian;WEI Yunjun;CHENG Feng;LUO Chao(China Machinery International Engineering Design & Research Institute Co., Ltd ., Changsha 410000, China;Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China)

机构地区：[1]中机国际工程设计研究院有限责任公司,湖南长沙410000 [2]中国科学院广州能源研究所,广东广州510640

出　　处：《热力发电》2019年第2期132-136,共5页Thermal Power Generation

基　　金：广东省科技计划项目(2013B091500087)~~

摘　　要：通过对国内供热改造技术现状的对比分析,选出背压小汽轮机供热改造方案作为靖远第二发电有限公司7号、8号机组供热改造方案。从7号、8号机组中低压联通管抽汽,一部分进入背压小汽轮机带动发电机发电,排汽分别进入2台前置加热器,将热网循环水加热至95℃;另一部分进入尖峰加热器,进一步将热网循环水加热至130℃来对外供暖。在非采暖期可以将供热系统解列,停止从主汽轮机中低压连通管抽汽,主汽轮机恢复纯凝工况运行。结果表明,在近期采暖负荷为107.2MW,采暖期为150天的条件下,供热改造后,年总供热量为1 389 826 GJ,年总节约标准煤量为36 068.7 t,CO2、SO2、NOx、年烟尘减排量分别为144007.6、167.7、196.6、196.4t。实际投产后的运行情况证明:背压小汽轮机供热改造方案系统清晰且运行稳定,节能减排收益可观,同时可以有效降低厂用电率,提高电厂发电上网量,为电厂创造了可观的效益;背压小汽轮机供热改造方案技术已成熟,在北方存在稳定采暖热负荷的城市值得推广。Based on comparative analysis on domestic heating retrofit technologies, the heating retrofit scheme of small back-pressure turbine was selected as the heating retrofit scheme for No.7 and No.8 unit of Jingyuan Second Power Co., Ltd. In this scheme, the heating steam is extracted from the connection pipe between the medium and the low pressure cylinder of the No.7 and No.8 steam turbine generator unit. Part of the steam is sent into the back-pressure steam turbine generators to produce electricity, and the exhaust steam is sent into two primary heaters to heat the circulating water to 95 ℃. The other part of the steam is sent into the peak-load heaters to further heat the circulating water to 130 ℃ so as to supply heat. In the non-heating period, the heating system can be decomposed, and the extraction of steam from connection pipe of the main steam turbine can be stopped.The result shows that, under the condition with heating load of 107.2 MW and heating period of 150 days, after the heating retrofit project was carried out, the annual total heating supply is 1 389 826 GJ, the total reduction of standard coal consumption is 36 068.7 t/a, the reduction of CO2, SO2, NOx and dust emissions is 144 007.6 t/a,167.7 t/a, 196.6 t/a and 196.4 t/a, respectively. The actual operation situation proves that, the small back-pressure turbine heating retrofit scheme, of which the system is clear and can stably operate, the energy conservation and emissions reduction of the project are profitable. Additionally, it can effectively reduce the auxiliary power consumption rate and increase the on-grid energy, which creates objective benefit for power plants. It is confirmed that the heating retrofit scheme technology of small back-pressure turbine is mature, and it is worth promoting in cities with stable heating load in North China.

关 键 词：供热改造 背压小汽轮机 热电联产 采暖系统 节能减排 灵活性 

分 类 号：TM621.4[电气工程—电力系统及自动化]