Study On Co₂ Capture Performance Using Alkanolamine Solvents In Rotating Packed Bed

At present,the phenomenon of global warming becomes more and more serious and CO2 emission account for 82%of total greenhouse gas emissions.It's really a great challenge for countries of the world to cut down the CO2 emission and relieve the environmental problems caused by the global warming.Alkanolamine absorption is one of the chemical absorption technology for CO2 capture,it's widely applied in the industrial CO2 removal process for its large absorption capacity,high purification and regeneration.However,conventional alkanolamine absorption process is conducted in the tower reactor,which is limited in mass transfer and equipment size,so that it's hard to realize efficient CO2 capture.In this work,rotating packed bed(RPB)was employed as a high effective reactor to intensify the CO2 absorption in alkanolamine solution,which mainly contained 2-((2-aminoethyl)amino)ethanol(AEEA).The effects of important operation conditions,such as high gravity level,amine solvent concentration,gas-liquid flow ratio,CO2 inlet concentration,absorption temperature and CO2 loading in amine solvent,on gas-phase volumetric mass transfer coefficient(KGa)and CO2 capture efficiency were investigated.Results indicated that the high gravity level and CO2 inlet concentration had significant effects on KGa.In the study of absorption process,the optimal operating conditions were 87?116 of high gravity level,140?160 L/L of gas-liquid ratio and 25%of absorbent concntration.The experimental value of KGa was about 1.42-2.86 kmol·m-3·h-1kPa-1 in RPB,which was an order of magnitude higher than that in a conventional packed column.Furthermore,an artificial neural network(ANN)model was applied to predict the mass transfer performance.The predicted values from the ANN model were in good agreement with experimental data(±10%).The motivation of third chapter focuses on the regeneration performance of the CO2 desorption process using two kinds of alkanolamine solvents in RPB.The performance of the process,which was shown in terms of the regeneration efficiency and liquid-phase volumetric mass transfer coefficient,was investigated experimentally under various conditions to evaluate the effects of operating variables,including RPB rotating speed,liquid flow rate,residence time in the reboiler and the inlet concentration of rich solutions.Results show that the idea to replace traditional packed bed stripper with RPB to regenerate the alkanolamine solvents absorbed with CO2,is feasible.And this idea is valuable for the reinforcement of desorption process and reducing the equipment cost.Considering the result of two systems of mixed alkanolamine and AEEA rich solutions,the RPB rotating speed,rich liquid flow rate,reboiler residence time and CO2 loading in rich liquid had a positive effect on the regeneration efficiency.However,increasing liquid flow rate and residence time would greatly increase the energy consumption,which was unfavorable for the whole regeneration system.In this study,the optimal operating conditions of the two experimental systems were 1000?1200 rpm of the rotating speed and 10 min of the reboiler residence time.Moreover,the performance of mass transfer and heat transfer in the RPB was 3.5 times of that in the traditional tower reactor.