Hydrogen purification devices and their components are disclosed. In some embodiments, the devices may include at least one foil-microscreen assembly disposed between and secured to first and second end frames. The at least one foil-microscreen assembly may include at least one hydrogen-selective membrane and at least one microscreen structure including a non-porous planar sheet having a plurality of apertures forming a plurality of fluid passages. The planar sheet may include generally opposed planar surfaces configured to provide support to the permeate side. The plurality of fluid passages may extend between the opposed surfaces. The at least one hydrogen-selective membrane may be metallurgically bonded to the at least one microscreen structure.

A method for generating Renewable Natural Gas (RNG) from raw biogas is disclosed, in which carbon dioxide is removed from biogas to generate pipeline specification RNG by a combination of absorption and membrane processes. The absorption process provides for the initial bulk carbon dioxide removal. The membrane process provides for the simultaneous removal of carbon dioxide and water vapors to pipeline specification. The method is characterized by a reduced separation energy consumption as compared to stand-alone membrane and absorption unit separations for biogas upgrading.

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 method for separating a raw feed gas stream using a plurality of membrane module stages. The raw feed gas stream may be from a biogas process. Off-gas from another unit process in the system, such as a temperature swing adsorption unit or liquefaction unit, may be used as a low pressure sweep gas on the low pressure side of at least one of the membrane module stages. In one example, the sweep gas is used in a first membrane module stage. In another example, a stripping membrane module stage is provided and the sweep gas is used in the stripping membrane module stage. Optionally, portions of the off-gas could be directed to other streams in the system for the purpose of balancing compressor power requirements.

Recovering helium from a gaseous stream includes contacting an acid gas removal membrane with a gaseous stream to yield a permeate stream and a residual stream, removing a majority of the acid gas from the residual stream to yield a first acid gas stream and a helium depleted clean gas stream, removing a majority of the acid gas from the permeate stream to yield a second acid gas stream and a helium rich stream, and removing helium from the helium rich stream to yield a helium product stream and a helium depleted stream. A helium removal system for removing helium from a gaseous stream including hydrocarbon gas, acid gas, and helium includes a first processing zone including a first acid gas removal unit, a second processing zone including a second acid gas removal unit, a third processing zone, and a helium purification unit.

A process for recovering sulfur and carbon dioxide from a sour gas stream, the process comprising the steps of: providing a sour gas stream to a membrane separation unit, the sour gas stream comprising hydrogen sulfide and carbon dioxide; separating the hydrogen sulfide from the carbon dioxide in the membrane separation unit to obtain a retentate stream and a first permeate stream, wherein the retentate stream comprises hydrogen sulfide, wherein the permeate stream comprises carbon dioxide; introducing the retentate stream to a sulfur recovery unit; processing the retentate stream in the sulfur recovery unit to produce a sulfur stream and a tail gas stream, wherein the sulfur stream comprises liquid sulfur; introducing the permeate stream to an amine absorption unit; and processing the permeate stream in the amine absorption unit to produce an enriched carbon dioxide stream.

Combustion systems are provided that can include a combustion assembly operatively engaged with an air intake, wherein the air intake performs air enrichment.

Methods for enriching air to a combustion assembly are also provided. The methods can include: forming an N.sub.2-rich stream and an O.sub.2-rich stream from a first air stream; supplementing a second air stream with the O.sub.2-rich stream to enrich the second air stream with O.sub.2; and combusting the enriched air stream.

Systems for separating CO.sub.2 from flue gas are also provided. The systems can include a vortex tube assembly operably coupled to a component of the system that provides pressurized N.sub.2.

Methods for heating or cooling components of a system for separating CO.sub.2 from flue gas are also provided. The methods can include: providing compressed nitrogen from one or more components of the system to a vortex tube to form a heated nitrogen stream and cooled nitrogen stream; providing the heated nitrogen stream to components benefiting from a heat source; and providing the cooled nitrogen stream to components benefiting from a cooling source.

Systems for separating CO.sub.2 from flue gas can also include a separation assembly that includes a membrane assembly configured to separate CO.sub.2 from N.sub.2.

Methods for separating CO.sub.2 from flue gas can also include providing a flue gas stream comprising CO.sub.2 and N.sub.2 to a first membrane separation system to form a CO.sub.2-rich stream and an N.sub.2-rich stream.

A device for separating a gas stream which has a compressor and three membrane separation units in series, connected to pass the retentate stream of each of the first two units to the subsequent membrane separation unit, comprises conduits for recycling the permeate streams of the second and the third membrane separation unit to upstream of the compressor and a control device controlling the fraction of the second permeate stream which is recycled. Adjusting which fraction of the second permeate is recycled can be used to maintain a target composition of the retentate obtained in the third membrane separation unit when the flow rate or the composition of the gas stream changes.

A plurality of membrane elements are arranged in series within a pressure vessel in which at least two of the elements exhibit different permeances or selectivities for a gas or gas pair respectively.

An approach for separating a gaseous mixture includes a multi-stage membrane system in which a rubbery membrane is operated at a low temperature. Various streams are cooled and heated in a multi-fluid heat exchanger. In specific configurations, the multi-fluid heat exchanger is cooled by using no fluids other than fluids derived from the permeate and/or residue generated in the first membrane stage.