Removal of CO2 and H2S using Aqueous Alkanolamine Solusions

Article. International Journal of Chemical and Biological Engineering 2:2 2009. — P. 78-87This work presents a theoretical investigation of the simultaneous absorption of CO₂ and H₂S into aqueous solutions of MDEA and DEA. In this process the acid components react with the basic alkanolamine solution via an exothermic, reversible reaction in a gas/liquid absorber. The use of amine solvents for gas sweetening has been investigated using process simulation programs called HYSYS and ASPEN. We use Electrolyte NRTL and Amine Package and Amines (experimental) equation of state. The effects of temperature and circulation rate and amine concentration and packed column and murphree efficiency on the rate of absorption were studied. When lean amine flow and concentration increase, CO₂ and H₂S absorption increase too. With the improvement of inlet amine temperature in absorber, CO₂ and H₂S penetrate to upper stages of absorber and absorption of acid gases in absorber decreases. The CO₂ concentration in the clean gas can be greatly influenced by the packing height, whereas for the H₂S concentration in the clean gas the
packing height plays a minor role. HYSYS software can not estimate murphree efficiency correctly and it applies the same contributions in all diagrams for HYSYS software. By improvement in murphree efficiency, maximum temperature of absorber decrease and the location of reaction transfer to the stages of bottoms absorber and the absorption of acid gases increase.