Carbon Dioxide Capturing from Natural Gas using Di-glycol Amine and Piperazine – A New Solvent Mixture

Abstract

The effect of adding Piperazine to di-glycol amine (DGA) to reduce the CO2 content in natural gas from 10% to 1% by mole was studied. Aspen HYSYS was used to simulate the process. Different concentrations of DGA (45, 50 and 55%) and Piperazine (3, 5, 7, 9 and 11%) were investigated. The effect of circulation rates variation from 1000 kgmol/hr. to 5000 kgmol/hr. were examined. Moreover, temperature ranges from 38 oC to 80 oC and pressure ranges from 45 kg/cm2 to 80 kg/cm2 were studied for 55% DGA without and with the addition of Piperazine. It was found that adding 9% Piperazine to 55% DGA achieved the best absorption efficiency. By using Piperazine, the circulation rate required to reach the 1% CO2 level was reduced to 3250 kgmol/hr. The amount of captured CO2 was found to increase with the decrease in the lean gas temperature and the increase in absorber pressure.