Simulation And Thermodynamic Performance Optimization Of Rectisol

Reducing carbon emissions is particularly important for environmental protection,but part of CO₂ is directly discharged into the atmosphere as a waste gas due to N₂ stripping in conventional Rectisol process.In order to improve the process to achieve the thermodynamic performance optimization,firstly,a conventional Rectisol process is simulated based on Aspen Plus in this dissertation.PSRK and CPA models,which have a good prediction of non-ideal system,are selected for physical property method,and the relevant binary interaction coefficients in the CPA model are corrected by regression.The result shows that both PSRK and CPA models have limitations in the simulation of local column system in the Rectisol process,while the revised CPA model can be applied to all columns,and the simulation results of the whole process are accurate compared with the actual data.Then,on the basis of the conventional Rectisol process,a four-stage pressurized hot flash and depressurized flash structure is proposed to replace the N₂ stripping tower for CO₂ capture.Related parameters of the first improved process are optimized by the spin-up method,and the optimization result is verified by the uniform test method.The result shows that compared with the conventional Rectisol process,the energy consumption of the first improved process increased by 2.12%,exergy consumption increased by 17.81%,but the CO₂ production is also increased and the exergy consumption per unit CO₂ decreased by 64.57%,which is a good improvement in CO₂ capture.In addition,the sensitivity analysis shows that the independent parameters,which include the first-stage temperature T_fi,second-stage pressure P_se and third-stage temperature T_th,have similar influence on the first improved process.Finally,based on the first improved process,a combined structure of"semi-lean solution+turbine recovery"is adopted to further improve energy saving.The result shows that the CO₂ production of the second improved process is not only equivalent to that of the first improved process,but also the process exergy consumption is reduced by 20.08%compared with the first improved process and 5.85%compared with the conventional Rectisol process.Therefore,the second improved process avoids the emission of CO₂ waste and has the effect of energy saving on the conventional process.The"semi-lean solution+turbine recovery"is a good combination of energy saving,because the"semi-lean solution"structure can save energy itself and strengthen the energy-saving effect of the"turbine recovery"structure.Moreover,the interior exergy loss of the second improved process is 23.79%lower than that of the conventional Rectisol process,indicating that its effective energy loss is lower in the process of energetic and material transfer and conversion.43 Figures,28 Tables,89 References...