Investigating the effect of absorbent material and heat flux in natural gas sweetening process using molecular dynamics simulation

Abstract

This study investigated the efficiency of various absorbents in the gas-sweetening process for removing corrosive acidic gases, specifically hydrogen sulfide (H₂S) and carbon dioxide (CO₂), from natural gas. The study used molecular dynamics simulations to investigate how well MEA, DEA, MDEA, and PC work as absorbents in various heat flux (HF) situations. The simulations demonstrated that all absorbents reached equilibrium within 10 ns, with potential and total energies stabilizing at 10.45 and 11.50 kcal/mol, respectively. The absorption efficiencies were 88.28 % for MEA, 81.06 % for DEA, 73.25 % for MDEA, and 64.11 % for PC, highlighting MEA as the most effective and PC as the least. MEA had an interaction energy of −131.58 kcal/mol, DEA had an interaction energy of −115.63 kcal/mol, MDEA had an interaction energy of −121.38 kcal/mol, and PC had an interaction energy of −73.09 kcal/mol. Increasing the external HF from 0.001 to 0.005 W/m2 enhanced the absorption rate of H₂S and CO₂ from 89.26 % to 95.18 % and increased interaction energy from −146.31 to −159.38 kcal/mol. These findings provided insights into optimizing gas-sweetening processes and selecting effective absorbents.

Keywords

• Heat flux
• Absorbent
• Sweetening process
• Sour gas
• Molecular dynamics simulation