CO2 desorption from activated DEA using membrane contactor with vacuum regeneration technology

Abstract

Carbondioxide (CO2) content in natural gas must be removed because it inhibits liquefication process of natural gas. CO2 gas separation technology using membrane contactor has been developed, however solvent regeneration using membrane contactors are still rare because it requires a larger energy. The regeneration process by using membrane vacuum technology was put forward to reduce the regeneration energy consumption. In this work, arginine, piperazine (PZ), and potassium carbonate (K2CO3) as activators were added into diethanolamine (DEA) solution to form aqueous solutions of activated DEA. The experiment of CO2 desorption from activated DEA was carried out in hollow fibre membrane contactor (HFMC). The solvent with rich CO2 at 30-70°C was flowed in the lumen of the hydrophobic polypropylene HFMC, and the shell side was maintained at a reduced pressure by a vacuum pump at 20 kPa. The effect of solvent temperature and activators were investigated to get CO2 desorption flux and regeneration efficiency. Experimental result shows that increasing of solvent temperature could enhance CO2 desorption flux and regeneration efficiency. Instead of that, the activated DEA also give better result compared with non-activated DEA. Among three activators, K2CO3 give the best result for desorption flux and regeneration efficiency.