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

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.