Analysis Of Energy Consumption And Approaches To Saving Energy In The Process Of CO₂ Absorption By MEA

Energy consumption of chemical separation process is the main of total energy consumption,so energy-saving has a great signality to separation process.In order to know the energy efficiency,it needs to do thermodynamic analysis in energy-saving research.The rapid development available energy analysis is extremely useful thermodynamic analysis in recent years.It can be know the energy efficiency in one process or equipment through available energy analysis.Then,it's possible to search for the way of energy saving and loss reducing.The technology of CO₂ recycle based on MEA is the most popular method in the recovery of CO₂,however,solution regeneration consume much energy.So,how to decrease the energy consumption now is generally considered as one of the most important problems urgently required to be settled.The traditional process of CO₂ absorption by MEA was simulated by the chemical engineering simulation software ASPEN PLUS.Based on the simulation results,the available energy consumption for the whole process and each equipment,thermodynamic efficiency of the whole process and the loss of available energy were analyzed,it also analyses tray efficiency by plate-to-plate available energy analysis method,and then,three suggestions for process improving were put forward.The first method is double-effect distillation using external energy,the second method is grading absorption,which energy consuming was decreased by less the amount of solution,which can be derived by lower mass transfer impulse,and the last method is heat pump distillation which depends on consuming some mechanical energy to rise low temperature steam.This paper firstly analyses the theoretical possibitity of the three energy-saving methods, then the three processes were simulated by ASPEN PLUS,meanwhile,available energy analysis is conducted.The results show that,on the basis of the CO₂ recovery and product purity are 80%and 98%respectively,the three new processes,compared with traditional process,achieve different energy saving effect.Among them,double-effect distillation, grading absorption and heat pump distillation are 21.30%,25.06%and 13.28%separately,the effectiveness of double-effect distillation and grading absorption are more remarkable than heat pump distillation.