间接空冷机组乏汽余热梯级利用技术方案研究

Analysis of the Technical Scheme of the Waste Heat Cascade Utilization in Indirect Air Cooling Unit

为积极响应国家余热暖民、节能减排、清洁供热、火电机组灵活性等产业政策,并结合供热发展需要,某2×350 MW间接空冷抽汽凝汽式供热机组进行供热能力增容改造。通过采用凝汽器乏汽外引再结合增汽机调压技术的余热梯级利用技术,利用新建前置凝汽器和增汽机与增汽机凝汽器及原有热网加热器形成三级梯级加热系统。采用该供热改造技术对比改造前抽汽供热,电厂供热能力提升394万m^(2),对应机组改造前供热能力增量83.1万GJ/a;全年平均发电标煤耗从改造前的263 g/kWh降低到242 g/kWh,回收乏汽量141.4万t,折合热值325.2万GJ,年节约标煤4.9万t。该技术方案实现了能量梯级利用,在提升供热能力的同时,节约煤炭消耗、提升电厂效益。

In order to actively respond to the national waste heat heating,energy saving and emission reduction,clean heating,thermal power unit flexibility and other industrial policies,and combined with the needs of heating development,a 2×350 MW indirect air cooling extraction steam condensing heat supply unit was transformed to increase heating capacity.Through the waste heat cascade utilization technology of introducing the exhaust steam from the condenser and combining the pressure regulation technology of the steam turbine,a three-stage cascade heating system is formed by using the newly-built front condenser and the steam turbine,the steam turbine condenser and the original heat network heater.The heating capacity of the power plant is increased by 3.94 million m^(2),corresponding to the heating capacity of the unit is increased by 831,000 GJ/a before the transformation,compared with the extraction steam heating before the transformation.The annual average standard coal consumption for power generation decreased from 263 g/kWh before the renovation to 242 g/kWh,and the lack of steam recovered was 1.414 million tons,equivalent to 3.252 million GJ of calorific value,saving 49,000 tons of standard coal annually.The technical scheme realizes the cascade utilization of energy,and saves coal consumption and improves the efficiency of power plant while improving the heating capacity.