摘要
随环境温度上升和建筑能效的提高,一次网供水温度从120～140℃降低到80～100℃,而常规热电联产机组的供热抽汽压力一般为0.3～0.5MPa,远高于热网加热器所需饱和蒸汽压力(0.07～0.14 MPa),换热过程存在较大■损,导致机组整体能效偏低。本文针对一种余压利用热网水加热系统,即供热抽汽先经过余压利用透平做功发电,再进入热网加热器加热热网水,以某300 MW热电联产机组为研究对象,对余压利用热网水加热系统进行热力学分析。结果表明:在基准供热工况下,与常规热网水加热系统相比,余压利用热网水加热系统的■效率增加了16.9百分点,促使机组的供电标准煤耗率降低19.12g/(kW·h),热电联产热效率提高了2.42百分点,节能效益显著。
With the increase of ambient temperature and the improvement of building energy efficiency, the supply-water temperature of the first-class heating network has decreased from 120~140 ℃ to 80~100 ℃, while the pressure of the extracted heating steam from the intermediate-pressure cylinder is generally 0.3~0.5 MPa in a conventional combined heat and power (CHP) unit, which is much higher than the needed steam pressure (0.07~0.14 MPa) of the supply-water heater. On account of superfluous steam pressure, a large exergy loss occurs in the heating process, resulting in a low energy efficiency of the unit. A heating system with waste pressure utilization (WPU) was introduced in this paper. The extraction steam firstly flows into the WPU turbine and drives the WPU generator to produce electricity, and then enters the supply-water heater to heat the supply-water. On the basis of a typical 300 MW CHP unit, the thermal performance of the new heating configuration was analyzed and assessed. The results show that, compared with the conventional heating system, the exergy efficiency of the improved heating system increased by 16.9 percentage points, which reduced the unit’s standard coal consumption rate by 19.12 g/(kW h), and raised the overall efficiency of the unit by 2.42 percentage points. The energy-saving benefits are significant.
作者
王立功
许继东
徐钢
陈衡
WANG Ligong;XU Jidong;XU Gang;CHEN Heng(Shenhua Shendong Power Co.,Ltd.,Xinjiang Midong Thermal Power Plant,Urumqi 830019,China;National Thermal Power Engineering and Technology Research Center,North China Electric Power University,Beijing 102206,China)
出处
《热力发电》
CAS
北大核心
2019年第5期8-13,共6页
Thermal Power Generation
基金
国家自然科学基金项目(51476053)~~
关键词
热电联产
节能机理
梯级利用
抽汽余压
敏感性分析
供热
cogeneration
energy saving mechanism
cascade utilization
extraction residual pressure
sensitivity analysis
heat supply
