A joint venture has been underway for several years to develop a membrane process to separate CO₂ and H₂S from high-pressure, sour natural gas. Typical feed and product conditions are:

To meet these conditions, the following hollow-fiber membrane material targets have been established:

where selectivity is the ratio of permeabilities. PMCO₂ = 13:3 barrer, and membrane skin thickness is expected to be 0.5 mm. Make calculations o show whether the targets can realistically meet the pipelinegas conditions in a single stage with a reasonable membrane area. Assume a feed-gas flow rate of 10 x 10³ scfm (0°C, 1 atm) with crossflow. Reference: Stam, H., in L. Cecille and J.-C. Toussaint, Eds., uture Industrial Prospects of Membrane Processes, Elsevier Applied Science, London, pp. 135–152 (1989).

Pressure, psia Composition, mol %: CH4 HS CO Feed Gas 1,000 70 10 20 Pipeline Gas 980 97.96 0.04 2.00