9F级燃气-蒸汽联合循环背压供热机组烟气余热深度利用工艺流程研究

Technology research on deep utilization of flue gas waste heat for 9F grade gas-steam combined cycle back pressure heat supply unit

针对一套二拖一大型9F级燃气-蒸汽联合循环背压供热机组,提出了烟气余热深度利用集成新工艺。该工艺在热力站处利用吸收式换热机组降低热网回水温度,在热源处通过两级加热实现烟气余热的深度回收,可将排烟温度降低到20℃左右,大幅提高了热源的供热能力和系统的供热效率,解决了燃气热电联产系统供热能力不足(热电比小)、燃气消耗量大的问题。与常规参考供热系统相比,该系统在输入燃气量不变、输出电力基本不变的前提下,全年回收烟气热量能够提高供热总量32.2%以上,供热面积可达1 655万m^2。对该工艺的流程进行了设计,全年运行工况分析结果表明,该工艺可以实现良好的节能、环保和经济效益。

According to a set of large 9F grade gas-steam combined cycle back pressure heat supply unit, proposes a new integrated process that can deeply recover the waste heat of flue gas. The new process can increase the temperature drop of the primary heating network, using absorption heat exchanger at the heating station, and deeply recover the flue gas waste heat in the heat source through two-stage heating process. It can reduce the outlet temperature of flue gas to about 20℃, greatly improving the heating capacity of the heat source and the heating efficiency of the system, and can solve the problems of insufficient heating capacity（small thermoelectric ratio） and large gas consumption of gas cogeneration system. On premise of same gas consumption and output power, the annual heat supply of new system can increase by more than 32.2%, and the heating area can cover around 16. 55 million square meters, comparing with the conventional heating system. Designs the technology process, and the analysis results of the yearly operating conditions show that the technology can achieve good energy conservation, environmental protection and economic benefits.