Simulation Analysis Of Flue Gas Dehumidification And Dewhitening System Based On Aspen Plus Heat Pump

A large number of coal-fired boilers in Chinese thermal power,industrial and thermal industries basically use wet desulfurization,but the emission of flue gas will cause white mist,After research,the particulate matter contained in the white mist is one of the causes of smog.In recent years,with the increasingly strict domestic requirements on environmental protection and energy,Provinces require the treatment of white mist from coal-fired boilers,and the recovery of waste heat and water.Therefore,“Flue gas dewhitening”technology is one of the main measures to solve the problem of smog.1.By referring to the literature,this paper studies and analyzes the mechanism of the generation and elimination of white mist in coal-fired power plants.Combining the mechanical and absorption heat pump methods,the flue gas condensation reheat technology is used.According to the humid air saturation moisture content map and the mechanical heat pump dehumidification and de-whitening system simulation,it is obtained that when the flue gas condensation temperature is 25℃,dehumidification and de-whitening effect is the best,and the dehydration rate reaches more than 80%.2.For the NH₃-H₂O absorption heat pump flue gas dehumidification and dewhitening system,after the optimization of the generator tray and feed position,as the temperature rises,the flue gas condensation temperature decreases,COP first rises and falls,When the tower bottom temperature is above 118°C,that is,the flue gas condensation temperature is below 35°C,the COP is at a relatively high level,around0.678.For the H₂O-Li Br absorption heat pump flue gas dehumidification and dewhitening system,as the temperature rises,the flue gas condensation temperature decreases and the COP gradually decreases.When the occurrence temperature is85-88℃,the COP is higher,when the flue gas condensation temperature is 42℃,the system cop reaches 1.29;With the increase of the inlet concentration of the generator,the flue gas condensation temperature increases,and the COP gradually increases.When the inlet mass concentration of the generator is above 57%,that is,the flue gas condensation temperature is above 40°C,the maximum COP can reach 1.68.3.Comparative analysis of the performance of the three flue gas dehumidification and dewhitening systems,The mechanical heat pump flue gas dehumidification and dewhitening system has a high COP,and the absorption heat pump flue gas dehumidification and whitening system has a good waste heat recovery effect.Although the mechanical flue gas dehumidification and whitening system has the most condensed water recovery,it needs to be sent to the desulfurization tower Hydration.Absorption heat pump flue gas dehumidification and de-whitening system can basically achieve no water replenishment while recovering the amount of water.Taking a 10t/h coal-fired boiler as an example,the annual water recovery can reach121,000 tons,and the theoretical thermal efficiency of the boiler is increased by 7.4%.