A process for providing a carbon monoxide-containing stream involves a separation of synthesis gas into a hydrogen-rich gas stream and a carbon monoxide-rich gas stream containing carbon monoxide to an extent of 85% by volume or more. The separation is effected in an arrangement composed of three membrane separation stages. Prior to the performance of the membrane separation, the synthesis gas is pretreated for removal of secondary components present in the synthesis gas.

The present invention involves the use of a two-step membrane system for gas separations. In this two-step membrane system, the membrane system comprises high selectivity and high permeance membranes. The two-step membrane system includes a first membrane section, a second membrane section and an ejector configured to increase the pressure of a lower permeate using the energy from a higher permeate gas pressure. The process provides increase in product recovery and product purity of the product gases. It can also save the cost compared to the system using compressors and external energy to drive the separation of gases.

The present invention concerns a method (100) for the production of a propylene product (9) in which a component mixture (2) containing propane, propylene and hydrogen is provided using a propane dehydrogenation (10) to which a reaction feed (1) containing propane and hydrogen is subjected, the component mixture (2) or a part thereof being subjected as a first separation feed to a first membrane separation (40), by means of which a first permeate (3) enriched in hydrogen with respect to the first separation feed and a first retentate (4) depleted in hydrogen with respect to the first separation feed and containing hydrogen, propane and propylene are formed, the first retentate (4) or part thereof being subjected to a second membrane separation (50) as a second separation feed, in which a second permeate (6) containing at least the predominant part of the hydrogen of the second separation feed and a second retentate containing at least the predominant part of the propane and the propylene of the second separation feed are formed, wherein the first membrane separation (40) is carried out using a sweep gas (5) containing propane and the first permeate (3) is obtained as a permeate (3) charged with propane of the sweep gas (5) and/or the second membrane separation (50) is carried out using the sweep gas (5) containing propane and the second permeate (6) is obtained as a permeate (6) charged with propane of the sweep gas (5), and wherein the first permeate (3) charged with propane of the sweep gas (5) and/or the second permeate (3) charged with propane of the sweep gas or one or more parts thereof is used in the formation of the reaction feed (1). A corresponding plant is also the subject of this invention.

A natural gas refining apparatus including a first separation membrane unit including a first separation membrane; and a second separation membrane unit provided in a subsequent stage of the first separation membrane unit. The second separation membrane unit includes a second separation membrane that allows an amine solution to circulate through the second separation membrane unit, and the natural gas refining apparatus refines raw natural gas containing CO.sub.2 by passing the raw natural gas through the first and second separation membrane units, separating CO.sub.2-rich gas with the first and second separation membranes, and absorbing CO.sub.2 with the amine solution circulating through the second separation membrane unit.

The invention relates to a method for membrane permeation of a gas flow including methane and carbon dioxide, wherein said gas flow is cooled to a temperature of 0° C. to −60° C. before being fed into a membrane separation unit.

The present invention provides a method for separating high purity methane gas from biogas, which comprises the steps of: compressing and cooling biogas (step 1); and separating carbon dioxide by introducing the biogas compressed and cooled in step 1 into a four-stage polymer separation membrane system in which the residue stream of the first polymer separation membrane is connected to the second polymer separation membrane, the residue stream of the second polymer separation membrane is connected to the third polymer separation membrane, and the permeate stream of the second polymer separation membrane is connected to the fourth polymer separation membrane (step 2).

An inert gas generation system from a flow of air, notably for an inerting system for at least one aircraft fuel tank. The generation system includes an air circuit having an air inlet, an inert gas outlet, and a first and a second air separation module arranged in series on the air circuit to deplete oxygen within the air and to generate a nitrogen-enriched inert gas.

A gas concentrating method and a gas concentrating device in which a large-capacity storage tank is not required and power consumption can be minimized are provided. A gas concentrating device (100) which concentrates a target gas including: a gas separating membrane module (3) including a gas separating membrane (1) and an accommodating container (2), a gas supply line (L1) through which a first mixed gas (G1) containing a target gas is supplied to the gas separating membrane module (3), a gas recovery line (L2) through which a second mixed gas (G2) containing a target gas is taken out from the gas separating membrane module (3), a gas discharge line (L3) through which an exhaust gas (G3) is discharged from the gas separating membrane module (3), and a raw material line (L0) through which a raw material (G0) to supplied to the gas supply line (L1), in which the raw material (G0) through the raw material line (L0) and the second mixed gas (G2) through the gas recovery line (L2) are supplied to the gas supply line (L1) and a gas concentrating method are provided.

An acidic gas separation module 10, which improves gas separation efficiency and reduces pressure loss, includes: a permeating gas collecting tube 12 having tube walls in which through holes 12A are formed; a layered body 14 that has at least an acidic gas separation layer 32 and that is wound on the permeating gas collecting tube 12; and telescope prevention plates 18 (a gas supply side 18A and a gas discharge side 18B) provided at both end faces in an axial direction of the wound layered body 14, wherein the ratio (D2/D1) of the open area ratio D2 of the telescope prevention plate on the gas discharge side 18B relative to the open area ratio D1 of the telescope prevention plate on the gas supply side 18A is from 0.5 to 0.9. An acidic gas separation device includes the acidic gas separation module 10.

A method of separating a composition containing at least one organofluorine compound from at least one inorganic compound by contacts the composition with a semipermeable membrane. Other methods separate a organofluorine compound from a composition containing at least one other organofluorine compound or chlorocarbon. Methods also include isolating a single organofluorine compound from a composition comprising a mixture of organofluorine compounds, chlorocarbons, and/or inorganic compounds.