CO₂ Capture And Desulfurization Process Of Syngas From Texaco Gasifier Based On [BMIM][Tf₂N]

The purification system of syngas in coal chemical production directly affects the stable operation of the whole coal gasification process and subsequent processes.Rectisol technology is a mature technology to remove acid gas from syngas,which consumes a lot of cold energy.Aiming at this problem,this paper puts forward the CO₂ capture and desulfurization process of Texaco gasifier based on[BMIM][Tf₂N],optimizes the process based on the multi-objective optimization method,combines the technology of waste heat refrigeration and waste heat power generation to improve the energy utilization efficiency of the process,and analyzes and evaluates the integrated process through energy,exergy,economy and environment.In this paper,a new process for the simultaneous removal of H₂S and CO₂ from syngas at room temperature using ionic liquid[BMIM][Tf₂N]as physical solvent is proposed.The removal rates of CO₂ and H₂S by this process are 97.6%and 95.3%respectively.Compared with the Rectisol Process,this process is superior in terms of the mole fraction of CO₂ in the CO₂ product gas and the removal rate of CO₂.At the same time,the loss rate of ionic liquid is low and the recovery energy consumption is low.Therefore,ionic liquid is a good alternative to cold methanol for large-scale CO₂ capture and H₂S removal.Based on the process of[BMIM][Tf₂N]syngas purification,thermal integration,CO₂ compression and transportation are added to improve the process.The results of energy,economy and environment analysis show that there is a contradiction between the economic performance and environmental performance of the process.In order to balance the contradiction,the non dominated sorting genetic algorithm with elite strategy is used to optimize the process.The calculated CO₂ emission and annual total cost of the multi-objective optimization scheme are 5.9%and 1.5%higher than the ideal minimum respectively.In view of the problems of high power consumption and cold energy consumption in the CO₂ capture and separation technology,an integrated process of organic Rankine cycle,absorption refrigeration cycle and synthetic gas purification process is proposed.Through the analysis and calculation of energy,energy,economy and environment,it is found that the thermal efficiency of organic Rankine cycle is 0.148,the performance coefficient of absorption refrigeration cycle is0.1058,the exergy efficiency of waste heat utilization system is 42.88%,the operation cost of integrated process is 81%lower than that of basic process,and the total equivalent CO₂ emission is 2.03 kg CO_2-eq/t.Therefore,the integrated process is conducive to the capture and separation of CO₂ in the coal chemical industry,as well as the optimization and improvement of low-grade waste heat utilization process.