Carbon molecular sieve membranes for biogas upgrading: Techno-economic feasibility analysis

• Published in: Journal of cleaner production 2018-09, Vol.194, p.584-593
• Main Authors: He, Xuezhong, Chu, Yunhan, Lindbråthen, Arne, Hillestad, Magne, Hägg, May-Britt
• Format: Article
• Language: English
• Subjects: Biogas upgrading; Carbon molecular sieve membrane; Cost estimation; Process simulation; Technology feasibility
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2018.05.172

Biomethane, produced by biogas upgrading, has a great potential to replace part of the fossil fuel natural gas, and may be injected into a gas grid or used as compressed biomethane as vehicle fuel. The state-of-the-art technologies for biogas upgrading in the European region are water scrubbing, pressure swing adsorption and chemical absorption, however, high performance carbon membranes may also have a great potential in this application. In this work, cellulose-derived hollow fiber carbon membranes were tested for CO2/CH4 separation at moderate pressures (5–20 bar), and a CO2/CH4 permeance selectivity >60 was obtained. The developed membranes were evaluated for biogas upgrading in a 1000 m3(STP)/h biogas plant based on HYSYS simulation and cost estimation. The results indicated that carbon membranes can be a promising candidate for biogas upgrading with a low processing cost of 0.078 $/m3 at the feed pressure of 8.5 bar. Increased membrane performance can further reduce the cost. Moreover, a carbon membrane system can be very cost-effective for upgrading of biogas in small-scale plants of around 350 m3(STP)/h. •A bench-scale carbon membrane module was tested for CO2/CH4 separation.•A two-stage membrane system was designed to achieve 98% CH4 at < 2% CH4 loss.•Technology feasibility of carbon membranes for biogas upgrading was documented.