高背压梯级供热技术工程应用研究

发布时间：2018-04-19 14:11

本文选题：热电联产 + 高背压　；参考：《华北电力大学(北京)》2017年硕士论文

【摘要】：热电联产是我国重大节能措施和电力生产重要组成部分。2016年3月,国家发改委、能源局等联合颁布了《热电联产管理办法》要求北方大中型城市热电联产集中供热率达到60%以上。预计未来将有大批燃煤发电机组进行热电联产改造或新建热电联产机组。高背压梯级供热技术是热电联产供热改造中重点关注和采用的技术。机组采用高背压梯级供热能降低冷源损失、提高循环热效率、扩大机组供热能力,达到热电联产系统的节能降耗。本论文涉及工作为国家科技支撑计划课题“火电机组汽轮机低位能梯级供热技术研究”任务的一部分,即为示范机组应用高背压梯级供热改造提供可研分析。本文详细论述了高背压梯级供热技术,针对示范机组确定集中供热的边界条件,应用Ebsilon软件建立高背压梯级供热机组变工况计算模型,在此基础上,进行了高背压梯级供热机组变工况性能分析,此外阐述了高背压梯级供热系统的热负荷分配计算方法,并采用热量分配法计算高背压供热机组的热经济性。针对示范电厂2*350MW超临界单抽供热机组,1号机组采用高背压梯级供热技术改造,2号机组仍采用原来的抽凝供热方式,结合当地实际供热参数和情况,计算分析该厂改造前后承担设计热负荷和承担最大供热能力的热经济性。结果表明:承担设计热负荷时,改造后供热季152天平均全厂发电标准煤耗率为205.46 g/kW·h;承担最大供热能力时,全厂发电标准煤耗率为199.07 g/kW·h,应用高背压梯级供热技术节能效果显著。对汽轮机排汽余热直供与抽汽耦合梯级供热系统(DCK供热系统)热负荷分配问题进行研究,以某实际热网为对象,针对DCK供热系统提出不同的近、远程热负荷分配方案。以系统热源、热网整体经济性为评价指标,结合近、远程热网调节变工况计算,计算不同热负荷分配方案下年折算收益,确定DCK系统最优热负荷分配方案。
[Abstract]:Cogeneration of heat and power is an important part of energy saving measures and power production in China. In March 2016, the National Development and Reform Commission,The Energy Bureau has jointly promulgated the measures for the management of cogeneration of heat and power, which requires the central heating rate of the cogeneration of heat and power in large and medium-sized cities in the north to reach more than 60%.It is expected that a large number of coal-fired generating units will be cogeneration retrofitted or newly built in the future.High back pressure cascade heating technology is one of the most important technologies in the cogeneration heating transformation.The unit adopts high back pressure cascade thermal energy supply to reduce the loss of cold source, to improve the cycle heat efficiency, to expand the heat supply capacity of the unit, and to achieve the energy saving and consumption reduction of the cogeneration system.This paper is concerned with a part of the task of "Research on low energy cascade heating technology of steam turbine", which is a part of the national science and technology support project, that is, to provide research and analysis for the application of high back pressure cascade heating system to demonstration units.In this paper, the technology of high backpressure cascade heating is discussed in detail. According to the boundary conditions of central heating for demonstration units, the calculation model of variable working conditions of high backpressure cascade heating units is established by using Ebsilon software.The performance analysis of high back pressure cascade heating unit is carried out. In addition, the calculation method of heat load distribution of high back pressure cascade heating system is expounded, and the heat economy of high back pressure heating unit is calculated by heat distribution method.In view of the 2*350MW supercritical single extraction heating unit in the demonstration power plant, the No. 1 unit is retrofitted with high backpressure cascade heating technology, and the No. 2 unit is still using the original pumping heating mode, combining with the local actual heating parameters and conditions.The thermal economy of design heat load and maximum heating capacity before and after revamping of the plant was calculated and analyzed.The results show that the standard coal consumption rate of the whole plant is 205.46 g/kW / h for the 152-day heating season and 199.07 g/kW / h for the maximum heating capacity, so the energy saving effect of the cascade heating technology with high backpressure is remarkable when the design heat load is taken on, and the standard coal consumption rate of the whole plant is 199.07 g/kW / h when the maximum heating capacity is assumed.The heat load distribution of steam turbine exhaust heat supply and exhaust cascade heating system is studied. Taking a practical heating network as an example, different near and long distance heat load distribution schemes are proposed for DCK heating system.Taking the heat source of the system and the overall economy of the heat network as the evaluation index, combined with the calculation of the near and remote heat network regulation and variable working conditions, the conversion income of different heat load distribution schemes in the next year is calculated, and the optimal heat load distribution scheme of the DCK system is determined.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM621

【参考文献】