Feasibility study of CO₂purification using pressure swing adsorption and triethylene glycol absorption for enhanced oil recovery

Abstract

In order to improve the quality and the separation effect of CO2 in X gas field, the influence of swing on removing of water content on purification of CO2 from offshore natural gas by pressure swing adsorption (PSA) and triethylene glycol (TEG) absorption was investigated by simulation. This method is to reduce the water content in the CO2 gas for enhanced oil recovery (EOR) method. In the EOR injection process at Y oil field, the purity of CO2 is more than 95%. The purity of CO2 plays an important role in determining the amount of oil that can be recovered. In system using PSA, the mass of activated carbon is needed of 11,555.3 lb/day, whereas by TEG absorption is required 91.27 gpm TEG adsorbent. Economic analysis was also carried out based on the oil yield that can be recovered from well (20.53 MMstb) using CO2 from X gas field for EOR injection in Y oil field. In PSA integrated system showed net present value (NPV) of 349,376,372.23 $ US, internal return rate (IRR) of 19.87%, with an investment cost of 214,918,114 $ US. The system integrated with TEG dehydration has an NPV of 390,869,013.8 $ US, IRR of 20.37%, and an investment cost of 240,111,000 $ US. These results showed that CO2 purification from X gas field is the most optimal and efficient when the system used the TEG absorption with NPV of 423,392,895.6 $ US, IRR of 20.71%, and payback period of 4.06 years. Based on the results of comparisons between the PSA and TEG features of upgrading technologies of CO2 in X gas field, the specific requirements for CO2-EOR in Y oil field, recommendations are made regarding appropriate technology for CO2-EOR