Patent ID: 8309348

Claim:
A method for converting a feed gas containing at least one of CO or a mixture of CO 2 and H 2 to a liquid product under anaerobic conditions, said method comprising: a) passing the feed gas to a gas contacting side of an asymmetric hydrophilic membrane that defines a bio-layer comprising an open surface presenting a plurality of bio-pores open to the gas contacting side and having effective diameters of at least 1 μm and that defines a hydration layer comprising a material that has a permeability less than permeability of the biolayer that controls the flow of liquid to and from the biolayer; b) retaining an anaerobic microorganism in the bio-pores and producing the liquid product by contact of the feed gas with the microorganisms; c) passing a fermentation liquid to a liquid contacting side of the hydration layer to permeate a portion of the fermentation liquid from the liquid contacting side into the bio-pores and into contact with the microorganisms; d) withdrawing the liquid product from the microorganisms by contact of the liquid product with the fermentation liquid so that the liquid product flows with the fermentation liquid from the bio-pores to the liquid contacting surface and the feed gas and the liquid product are in co-directional flow; e) maintaining the feed gas on the gas contacting side of the membrane at a pressure above the pressure of the fermentation liquid on the liquid contacting side of the membrane by an amount that prevents the convective liquid flow from the hydration layer to the open surface of the gas contacting side of the asymmetric membrane; f) recovering a fermentation liquid containing the liquid product from the liquid contacting side; and, g) separating the liquid product from the fermentation liquid to recover the liquid product.