330MW供热机组低压缸近零出力热力性能分析

阐述了汽轮机低压缸切缸供热系统工作机理，结合某330MW空冷供热机组，应用Ebsilon软件搭建切缸供热改造前后机组变工况计算模型，基于热力学定律，对比分析改造前后机组能耗分布和供热能力。绘制了纯凝运行、抽汽供热和切缸供热工况能流图，获得机组在不同供热方式下能量流动方向和各部分损失变化。探讨影响机组调峰范围的因素，利用工况图分析低压缸近零出力改造后电热负荷特性及其调峰能力的变化。并结合电力辅助服务市场运营规则进行了调峰补偿收益核算。结果表明：较抽凝运行工况，案例机组完成低压缸近零出力改造后，最大供热能力增加37.1%；额定供热工况电负荷调节能力提高34.8%；发电标准煤耗率降低54.5g/(kW·h), 调峰能力增加的同时热经济性提高。本文从理论上，对低压缸近零出力改造技术的应用提供了定量依据和工程适用范围，为热电联产机组灵活性改造技术应用提供理论支撑。

Thermal performance analysis of 330MW heating unit with low pressure cylinder near zero output

The working mechanism of the steam turbine low-pressure cylinder cutting cylinder heating system is described. Combined with a 330MW air-cooled heating unit, Ebsilon software is used to build the calculation model of the unit's variable operating conditions before and after the cutting cylinder heating transformation. Based on the laws of thermodynamics, the energy consumption distribution and heating capacity of the unit before and after the transformation are compared and analyzed. The energy flow diagram of pure condensing operation, extraction heating and cutting cylinder heating is drawn to obtain the change of energy flow direction and loss of each part of the unit under different heating modes. The factors influencing the range of peak regulation of the unit are discussed and the characteristics of electric load and the change of peak regulation capacity of the low-pressure cylinder are analyzed by using the working diagram. Combined with the operation rules of power auxiliary service market, the calculation of peak compensation income is carried out. The results show that: compared with the pumping and condensing operation condition, the maximum heating capacity of the case unit is increased by 37.1% after completing the transformation of low-pressure cylinder near zero output; the adjustment capacity of electrical load in rated heating condition is increased by 34.8%; the standard coal consumption rate of power generation is reduced by 54.5g/kW·h, and the peak regulation capacity is increased while the thermal economy is improved. In theory, this paper provides quantitative basis and engineering scope for the application of low-pressure cylinder near zero output transformation technology, and provides theoretical support for the application of cogeneration unit flexibility transformation technology.