燃煤电厂与醇胺法碳捕集系统耦合方案的改进及经济性分析

针对碳捕集系统再生能耗高的问题，以我国600 MW超临界燃煤机组为研究对象，分析了机组8段抽汽的品位，引入可以提高低压蒸汽压力的专用设备--汽汽引射器，提出了碳捕集系统与燃煤发电机组的耦合方案，建立了发电机组的经济性指标，研究了碳税价格和碳售出价格对发电机组发电成本的影响。研究结果表明：当碳捕集率取85%、MEA吸收剂质量分数取30%时，二氧化碳捕集单位再生能耗为3.84 GJ/(t CO2)；耦合机组发电成本随碳税价格的升高而有所升高，随着碳售出价格的升高而降低；参考机组的发电成本随碳税价格的升高而明显升高，不随碳售出价格的变化而变化；当系统操作参数一定时，耦合发电系统全厂热效率为37.05%，与非耦合系统的热效率43.14%相比，降低了6.09%，发电标准煤耗升高了0.047 g/(kW·h)，发电成本增加了0.171元/(kW·h)。

A modification and economical analysis for the coupling between coal-fired unit and carbon capture system based on MEA

In order to overcome the problem of a high energy consumption caused by the carbon capture system (CCS) with a coal-fired unit from China,the energy-grade of eight levels of the unit was analyzed,a dedicated device,named as ejector for improving the pressure of a low-pressure steam,was used.The coupling method of the coal-fired unit and CCS was proposed,the economic index of the unit was established and the effect of the tax price and sale price of carbon on the cost of electricity generation of the unit was investigated.The results show that a carbon capture rate of 85% and an absorbent mass fraction of 30% result in an carbon capture energy consumption of 3.84 GJ per tonne of CO2,and a higher carbon capture rate results in a higher mass flow rate of all fluid.The electricity generation cost of the coupled unit increases as the carbon tax price increases or the carbon sale price decreases；the electricity generation cost of original unit increases as the carbon tax price increases and is independent of the carbon sale price.With a set of constant operational parameters,the coupled unit gets an overall heat efficiency of 37.05%,6.09% lower than 43.14% of the original unit.Compared to the original unit,the standard coal of electricity generation for the coupled unit increases 0.047 g/(kW·h) and the electricity generation cost increases 0.171 Yuan/(kW·h).