Techno-economic analysis of acid gas removal from associated and non-associated sour gas using amine blend

Acid gas removal (AGR) is a critical step in the supply chain of natural gas for its safe transmission and clean combustion. Chemical amines are the most commonly employed commercial solvents for the gas cleaning. Due to energy intensive nature of the AGR process, ways to improve process efficiency are vital. This study investigated the removal of acid gases from the associated and non-associated sour feeds using a blend of diglycolamine (DGA) and methyldiethanolamine (MDEA) solvents at a total strength of 50 wt. %. Steady-state process simulation models have been developed to seek the process improvement by utilization of amine blends. The study performed a detailed energy and economic analysis to understand the feasibility of the investigated amine blends. The results show that when 45 wt. % DGA is mixed 5 wt. % MDEA additive for the processing of associated gas, a saving of 3.42 $/MMSCF of sweet gas produced is achieved. On the other hand, cost per MMSCF of sweet gas increases significantly when DGA additive is mixed with MDEA amine for the processing of non-associated gas.