Study On The Modification And Integration Of CO₂ Chemical Absorption Process

CO₂ capture using chemisorption is one of the most mature options in post-combustion CO₂ capture technologies,but suffering from high energy consumption and overwhelming investment.This work aimed to lower the energy consumption of novel process with MEA as solvent.The operation parameters and modified processes?inter cooling,rich solvent split,direct steam stripping?have been tested to achieve lower energy-consuming process package.In this work,rate-based model in Aspen plus was used to simulate the process of CO₂ chemical absorption with 1 million ton CO₂/year captured to evaluate the absorption and desorption performances and investigate the temperature and pressure profiles along the columns.On the basis of the basic case,the sensitivity of the major parameters on the absorption-desorption of MEA was analyzed to observe their effects on the regeneration water consumption,and cooling water usage,etc.The results showed that lean solvent loading,solvent mass flow rate,solvent concentration,lean-rich solvent heat exchanger and the pressure of desorption column had significant effects on the regeneration energy consumption of MEA.Whereas,the effects of temperature of lean solvent entering the absorber and flue gas temperature were insignificant.The inter cooling and rich solvent spilt processed was integrated with the typical process to achieve lower energy consumption.The results showed that the CO₂ desorption energy consumption of the new process was 3.02GJ/tCO₂,24.3%lower than the basic case.MEA,AMP,and PZ were used in the novel direct steam stripping process.The simulation results showed that the novel process could reduce the energy consumption to 70-80%of the conventional stripping process and could also lower the lean solvent loading of CO₂.MEA was fitted the novel process best and strong phenomenon of flashing was discovered through the study of mass and heat transfer,which was beneficial to lower the massive energy consumption of water evaporation.Finally,the techno-economic model was established to calculate the investment and operational cost of the demonstration project of 1 million ton CO₂/year captured.The total investment was 0.726 billion RMB,in which the direct investment of all the equipment was 0.304 billion RMB.The operational cost was 185.03 RMB/tCO₂ and the overall capture cost was 209.2 RMB/tCO₂,which was 19.7%lower than the basic case.The economic performance of integrated CO₂ capture process improved significantly thorough parameter optimization and process integration,which was of industrial instruction to other projects.