Energy, Equipment and Cost Savings by Using a Membrane Unit in an Amine-Based Absorption Process for CO2 Removal



A hybrid system consisting of a membrane unit and an amine-based process for CO2 removal in the oxidative coupling of methane is investigated experimentally and in simulations. Absorption processes with two different absorbents for removing 90 % of CO2 from the feed stream are regarded as benchmarks and compared to the membrane process with respect to potential energy, equipment, and cost reductions. The results show that a membrane unit using polyimide could assist with CO2 capture and lead to a reduction of the consumed energy per kilogram of CO2 by 40 % and also reduce the size of the absorption columns. Alternative processes with a two-step membrane cascade to enhance the recovery of product ethylene are also discussed.