Encyclopedia of Membranes

Living Edition
| Editors: Enrico Drioli, Lidietta Giorno

Acid Gas: Effect on Membrane Properties

Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-40872-4_817-3

Acidic gas removal is the largest application of gas separation membranes and a vital process in the natural gas processing industry. Membranes used in this process are designed to separate H2S and CO2, and this process is known as natural gas sweetening. This is readily required for low-quality natural gas reserves, which need to be processed to achieve pipeline specifications of CO2 <2 mol% and H2S <4 ppm (Baker 2001). The removal of acidic gases is also required for biogas and gasification, where H2S and CO2 are separated from CH4, CO, and H2. For natural gas sweetening, the membrane must exhibit high permeability for H2S and CO2, with a large selectivity relative to methane.

In general, nonporous polymeric membranes are applied in acidic gas removal, taking advantage of the solution-diffusion mechanism and the high solubility of H2S and CO2, compared to CH4. Also polymeric membranes almost always demonstrate selectivity for H2S over CO2, again because of the higher condensability...
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Authors and Affiliations

  1. 1.Department of Chemical & Biomolecular EngineeringThe University of MelbourneParkvilleAustralia