LAUSR

ABSTRACTBiogas can be upgraded to biomethane through CO2 removal as a sustainable replacement of natural gas. Membrane systems that are based on a two-step design have emerged as an attractive approach for the CO2 removal. The objective of this work is to determine optimal membranes for this application by performing process simulation and techno-economic analysis. Practical membranes with the trade-off of CO2 permeance and CO2/CH4 selectivity on the Robeson’s upper bound are considered, and the membranes in the two steps are varied independently. Optimal membranes should have high CO2 permeance with sufficient CO2/CH4 selectivity (10–25) to achieve the lowest operating cost for the CO2 removal.