Method for injecting a feed gas stream into a vertically extended column of liquid

A process for converting a feed gas stream, comprising at least one of CO or a mixture of CO2 and H2, to a liquid product by contact with a fermentation liquid wherein the liquid product reduces the surface tension of the fermentation liquid, said process comprising:

• a) retaining an aqueous fermentation liquid comprising a liquid product and microorganisms in a bioreactor vessel that extends vertically to height such that the fermentation liquid creates more than 100 kPa of hydrostatic pressure;
• b) withdrawing fermentation liquid containing the liquid product from said vessel at a withdrawal point and pumping a portion of said fermentation liquid as a primary working fluid to a primary gas injector;
• c) passing at least a portion of the feed gas stream into the primary gas injector at a pressure of not more than 100 kPa gauge;
• d) mixing the feed gas stream with the primary working fluid and using the pumping of the primary working fluid as the primary energy input to produce a primary gas-liquid dispersion from the feed gas stream and the primary working fluid that flows out of the gas injector and contains microbubbles;
• e) adding a supplemental working fluid to the primary gas-liquid dispersion from the primary gas injector to produce a primary mixed dispersion containing microbubbles;
• f) passing at least a portion of one of the primary mixed dispersion or the primary gas-liquid dispersion into the inlet of a primary dispersion conduit having a vertical length of at least 10 meters;
• g) discharging the primary mixed dispersion from the primary dispersion conduit into the vessel at a primary discharge point located at least 10 meters below the primary gas injector, wherein the addition of supplemental working liquid in accordance with step e) takes place at location that is downstream of the mixing of the feed gas stream with the primary working fluid and upstream of the primary discharge point;
• h) converting at least one of the CO or the mixture of CO2 and H2 to the liquid product in said vessel by contact of the microorganisms with the fermentation liquid that contains dissolved and un-dissolved feed gas from the primary mixed dispersion;
• and,
• i) passing a portion of the fermentation liquid from the vessel to a product recovery zone and recovering a product stream comprising the liquid product from said product recovery zone.