燃煤烟气碳捕集系统压缩、干燥与液化设备选型

The product processing devices of the flue gas carbon capture system of coal-fired power plants include compression, drying andliquefaction devices, and their selection determines the product gas quality. Based on the 500 000 t/ a flue gas CO2 wet capture project of a1 000 MW thermal power plant, this paper conducted a comparative study and analysis on the selection of CO2 compressors, refrigerationliquefiers and other equipment required for the compression, liquefaction and cooling processes of the CO2 gas compression system in viewof the characteristics of the wet absorption process, such as high CO2 gas moisture content, large gas volume but low compressionpressure, combined with the operating restrictions of power generation and heat supply of the power plant. The adaptability of chemical system equipment applied to power production units was also discussed. The results show that the type selection of CO2 capture device forflue gas of coal-fired power plants is greatly different from that of petrochemical units. Compared with the pursuit of stability of the load ofpetrochemical units, the load fluctuation of modern thermal power plants during peak shaving operation is extremely strong. The CCUS project of thermal power plants uses power plant smoke as raw material, uses power plant waste heat steam, takes up the share of power consumption, and shares circulating water, closed water, compressed air and other production materials, leading to the fluctuation of flue gasvolume, power steam parameters, flue gas CO2 concentration, cooling water source, etc. The design boundary conditions for the selectionof heat exchanger and compressor are different from those of petrochemical units. In general, coal-fired power plants and petrochemicalenterprises are located in different locations. Most of the petrochemical enterprises are located in the same chemical industry zone as upstream and downstream enterprises. Thermal power plants are not adjacent to CO2 consuming units. The product gas quality standards, gaspackaging and transportation equipment of CCUS units of thermal power plants need to be differentiated from chemical units based on regional and market positioning. Compared with chemical units, the CCUS project of coal-fired power plant has the advantage of lower powersource cost. Power plant projects should consider reducing the cost of absorbent loss more, instead of blindly pursuing to reduce energy consumption costs.