A fluid separation apparatus comprising a fluid separation membrane is provided. The fluid separation apparatus comprises a fluid separation membrane extending in one direction and having a cross-section with a closed curve shape, wherein the fluid separation membrane has a thickness of 0.1 mm to 2 mm, and an outer diameter of 60 mm to 360 mm when the cross-section is adjusted to be circular.

A natural-gas purification apparatus includes: a compressor that adjusts the pressure of natural gas, and a separation device that separates natural-gas liquid and carbon dioxide from the natural gas after the pressure adjustment by the compressor through a natural-gas-liquid separation membrane and a carbon-dioxide separation membrane.

A gas separation module and assembly for housing ceramic tubular membranes. The module includes a plurality of tubes containing the ceramic tubular membranes. The tubes are arranged parallel to one another and are supported by tube sheet plates at each end. Gas-tight seals surround each membrane, preventing a feed gas and a residue gas within the inner lumen of the membrane from mixing with a permeate gas in the tube interior. The module also contains a gas distribution pipe for withdrawing the permeate gas out of, or introducing a sweep gas into, the module. This configuration allows for ceramic tubular membranes to be modularized for use in an assembly that carries out many types of gas separations.

A system and method for producing hydrogen, including providing hydrocarbon and steam into a vessel to a region external to a tubular membrane in the vessel. The method includes steam reforming the hydrocarbon in the vessel via reforming catalyst to generate hydrogen and carbon dioxide. The method includes diffusing the hydrogen through the tubular membrane into a bore of the tubular membrane, wherein the tubular membrane is hydrogen selective.

Provided is a facilitated CO.sub.2 transport membrane having an improved CO.sub.2 permeance and an improved CO.sub.2/H.sub.2 selectivity. The facilitated CO.sub.2 transport membrane includes a separation-functional membrane that includes a hydrophilic polymer gel membrane containing a CO.sub.2 carrier and a CO.sub.2 hydration catalyst. Further preferably, the CO.sub.2 hydration catalyst at least has catalytic activity at a temperature of 100? C. or higher, has a melting point of 200? C. or higher, or is soluble in water.

A carbon dioxide separation method including the steps of: feeding a mixed gas that contains at least carbon dioxide and water vapor to a carbon dioxide separation membrane that contains a hydrophilic resin and a carbon dioxide carrier; separating, from the mixed gas, a permeation gas that contains the carbon dioxide by use of the carbon dioxide separation membrane; adjusting temperature of gas which contacts the carbon dioxide separation membrane so that a temperature difference between the mixed gas and the permeation gas is not lower than 0? C. and not higher than 20? C.; and adjusting pressure of the permeation gas, the pressure of the permeation gas and water vapor partial pressure in the mixed gas satisfying the following formula (1): 2.5 kPaA<(pressure of permeation gas)<(water vapor partial pressure in mixed gas) . . . (1).

Provided is a facilitated CO.sub.2 transport membrane having an improved CO.sub.2 permeance and an improved CO.sub.2/H.sub.2 selectivity. The facilitated CO.sub.2 transport membrane includes a separation-functional membrane that includes a hydrophilic polymer gel membrane containing a CO.sub.2 carrier and a CO.sub.2 hydration catalyst. Further preferably, the CO.sub.2 hydration catalyst at least has catalytic activity at a temperature of 100? C. or higher, has a melting point of 200? C. or higher, or is soluble in water.

A method for conditioning natural gas into fuel gas, where the method includes the step of: delivering a natural gas stream including both CO.sub.2 and C2+ hydrocarbons to a membrane separation assembly; and separating the natural gas stream into the following streams: (i) a first permeate stream, (ii) a second permeate stream, and (iii) a residual stream. The first permeate stream includes CO.sub.2 removed from the natural gas stream. The second permeate stream includes methane at a greater concentration than a concentration of methane in the natural gas stream. The residual stream contains C2+ hydrocarbons at a greater concentration than a concentration of C2+ hydrocarbons in the natural gas stream.

Provided are an apparatus for separating and collecting carbon dioxide and a method of separating carbon dioxide, and more particularly, an apparatus and method of selectively separating carbon dioxide from a byproduct gas using a difference in negative pressure and a difference in carbon dioxide concentration between the inside of a separator, which is made of a ceramic-coated porous silicone membrane and in which the byproduct gas flows, and the outside of the separator in which carbon dioxide is collected.

A system for an internal combustion engine can include a separation device and an engine component including first and second valves. The separation device can separate intake air into a volume of nitrogen-rich air and a volume of oxygen-rich air. A first valve element can be movable relative to a first valve body and can have an annular shape disposed about a central axis of the combustion chamber. The first valve body can be fluidly coupled to the separation device and direct the oxygen-rich air into a central area of the combustion chamber. A second valve element can be movable relative to a second valve body and can have an annular shape disposed about the central axis, radially outward of the first valve. The second valve body can be fluidly coupled to the separation device and can direct the nitrogen-rich air to a peripheral area of the combustion chamber.