新型燃煤电厂发电−脱碳−供热一体化的耦合系统

Coupling system of power generation, decarbonization and heat supply integration in new coal-fired power plant

  • 摘要: 伴随着能源需求的提高,所伴随而来的环境问题也日益加剧,燃烧产生的CO2便是温室气体的直接来源,其中燃煤电厂是主要碳排放源,且在生产过程中产生大量的余热。燃煤电厂脱碳系统和热电联产系统对热源温度要求相近,针对这一特性,可以在控制燃煤电厂的碳排放量的同时,对其过程中产生的余热进行回收利用,提高系统的供热能力。基于燃煤电厂发电系统、固体胺吸收剂脱碳系统以及一次/二次供热系统,创新性地提出了一种发电−脱碳−供热一体化的耦合系统。引入背压式供热汽轮机和背压式脱碳汽轮机取代低压汽轮机,以背压式供热汽轮机和背压式脱碳汽轮机的排汽分别给供热过程和脱碳过程提供热源,在保证脱碳能力的前提下显著降低了耦合系统的发电能力损失。为再进一步提高耦合系统的热力性能,采用吸收式换热技术高效回收脱碳系统释放的低温余热,提高耦合系统的供热能力。计算结果显示,新型发电−脱碳−供热一体化的耦合系统回收了90%以上脱碳系统释放的低温余热,系统的供热能力由785.06 MW提升至1288.94 MW,供热能力升高65%,节能效果显著。

     

    Abstract: With the increase of energy demand, the accompanying environmental problems are also increasing. The CO2 generated by combustion is the direct source of greenhouse gases, and coal-fired power plants are the main source of carbon emissions, and a lot of waste heat is generated in the production process. The decarbonization system of coal-fired power plant and the cogeneration system have similar heat source temperature requirements. Therefore, the waste heat generated in the process can be recycled while controlling the carbon emissions of the coal-fired power plant, and the heating capacity of the system can be improved. Based on the power generation system of coal-fired power plant, solid amine absorbent decarbonization system and primary/secondary heating system, an integrated coupling system of power generation, decarbonization and heating is proposed innovatively. The back-pressure heating steam turbine and back-pressure decarburization steam turbine are introduced to replace the low-pressure steam turbine, and the exhaust steam of the back-pressure heating steam turbine and the back-pressure decarburization steam turbine provide heat sources for the heating process and the decarburization process respectively. On the premise of ensuring decarbonization capacity, the power generation capacity loss of the coupled system is significantly reduced. In order to further improve the thermal performance of the coupling system, the absorption heat transfer technology is used to recover the low-temperature waste heat released by the decarbonization system and improve the heating capacity of the coupling system. The calculation results show that more than 90% of the low-temperature waste heat released by the system is recovered by the new power-decarbonization and heat-supply coupling system. The heating capacity of the system is increased from 785.06 MW to 1 288.94 MW, and the heating capacity is increased by 65%.

     

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