A method for recovering helium from a feed gas mixture comprising helium, carbon dioxide and at least one of methane and nitrogen, and wherein at least a part of the feed gas mixture is subjected to a separation sequence including a membrane-based separation and an adsorption-based separation forming a helium product, wherein the the membrane based separation is performed using a first membrane separation step and a second membrane separation step, the membrane based separation and the separation sequence includes no further membrane separation steps, the adsorption based separation is performed using a pressure swing adsorption step, at least a part of the feed gas mixture is subjected to the first membrane separation step forming a first retentate and a first permeate. A corresponding arrangement is also provided.

The present disclosure provides systems and methods for hydrogen production as well as apparatuses useful in such systems and methods. Hydrogen is produced by steam reforming of a hydrocarbon in a gas heated reformer that is heated using one or more streams comprising combustion products of a fuel in an oxidant, preferably in the presence of a carbon dioxide circulating stream.

The invention provides a process for producing a fermentable gas stream from a gas source that contains one or more constituent which may be harmful to the fermentation process. To produce the fermentable gas stream, the gas stream is passed through a specifically ordered series of removal modules. The removal modules remove and/or convert various constituents found in the gas stream which may have harmful effects on downstream removal modules and/or inhibitory effects on downstream gas fermenting microorganisms. At least a portion of the fermentable gas stream is preferably capable of being passed to a bioreactor, which contains gas fermenting microorganisms, without inhibiting the fermentation process.

Novel methods for pretreating a rare-gas-containing stream exiting an etch chamber followed by recovering the rare gas from the pre-treated, rare-gas containing stream are disclosed. More particularly, the invention relates to the pretreatment and recovery of a rare gas, such as xenon or krypton, from a nitrogen-based exhaust stream with specific gaseous impurities generated during an etch process that is performed as part of a semiconductor fabrication process.

The present disclosure is directed to a potassium-form MER framework type zeolite, a MER framework type zeolite having a stick-like morphology, wherein the potassium is present as K.sup.+ in extra-framework locations. The zeolite is essentially free of an extra-framework cation other than potassium.

A method of obtaining helium from a helium-containing feed gas. Helium-containing feed gas is fed to a prepurifying unit that uses a pressure swing adsorption process to remove undesirable components from the helium-containing feed gas and obtain a prepurified feed gas. The prepurified feed gas is fed to a membrane unit connected downstream of the prepurifying unit and that has at least one membrane more readily permeable to helium than to at least one further component present in the prepurified feed gas. A pressurized low-helium retentate stream that has not passed through the membrane is fed to the prepurifying unit. The pressurized low-helium retentate is used to displace helium-rich gas from an adsorber that is to be regenerated into an already regenerated adsorber.

A method of obtaining helium from a process gas. The process gas is at a pressure less than 15 bar to a first membrane separation stage having a first membrane more readily permeable for helium than for at least one other component in the process gas. A first retentate stream is fed to a second membrane separation stage having a second membrane more readily permeable for helium than for at least one other component in the process gas. Helium is separated from a first helium-containing permeate stream using a pressure swing adsorption to obtain a helium-containing product stream. A second helium-containing permeate stream is recycled to the first membrane separation stage. A purge gas from the pressure swing adsorption is also recycled to the first membrane separation stage.

The invention relates to an internal combustion engine that comprises a first Brayton cycle comprising a mixed ionic-electronic conducting (MIEC) membrane that separates the O.sub.2 from the air such that the suctioned air current is free from N.sub.2; a second Brayton cycle combined in a binary manner with the first Brayton cycle and nested with a cycle selected from an Otto cycle and a diesel cycle performed by means of oxy-combustion. The second Brayton cycle transmits mechanical energy and thermal energy from exhaust gases to the first Brayton cycle. The first Brayton cycle provides to the second Brayton cycle compressed O.sub.2 from the MIEC membrane. By means of the present engine, the NOx emission into the atmosphere is prevented by the separation of N.sub.2 in the MIEC membrane.

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.

The invention provides a process of purifying a fluid useful in a manufacturing process, particularly in the manufacture of silicon wafers, by removing one or more impurities; and apparatus for use in the process.