Impact of high pressure on high concentration carbon dioxide capture from natural gas by monoethanolamine/N-methyl-2-pyrrolidone solvent in absorption packed column

• This paper investigates the absorption of CO2 at high concentration level of 50% from mixture of CO2–natural gas.
• Condition tested was up to 5 MPa for MEA aqueous solution and MEA hybrid solution in countercurrent packed column.
• Increase of pressure was found to have a positive impact of CO2 removal performance.
• This trend was especially significant when the pressure was at 5 MPa.

Carbon dioxide (CO2) removal is an essential step in natural gas (NG) processing to provide high quality gas stream products and minimize operational difficulties. This study aims to investigate the absorption performance of CO2 at high concentration level of 50% from a mixture of CO2–NG gas stream at pressure condition of up to 5 MPa for 20 wt% monoethanolamine (MEA) aqueous solution and MEA hybrid solution consisting of 20 wt% MEA with 40 wt% N-methyl-2-pyrrolidone (NMP) + 40 wt% water in a countercurrent packed column. Comparison of absorption performance was also conducted with water and NMP in order to understand the effect of physical absorption by the individual solvent respectively. It was observed that water had minimal physical absorption for CO2. On the contrary, NMP was observed to be an efficient physical absorbent for CO2 on its own. Increased pressure was found to have a positive impact on the CO2 removal performance for water, NMP, MEA aqueous solution and MEA hybrid solution. This trend was especially significant when the pressure was at 5 MPa.