Methods of controlling hydrogen sulfide concentration of a biogas occupying an anaerobic membrane bioreactor (AnMBR) containing a submerged membrane are disclosed herein. Methods of controlling dissolved sulfide concentration of a mixed liquor within the AnMBR are disclosed. The methods include directing wastewater containing sulfur and a chemical oxygen demand (COD) to an AnMBR, withdrawing at least a fraction of the biogas from the AnMBR, directing a pre-determined amount of the withdrawn biogas to a scrubber, directing a remainder of the withdrawn biogas to a gas distributor, and directing the scrubbed biogas to the AnMBR. Systems for treating wastewater having sulfur and COD are disclosed. The systems include an AnMBR, a scouring gas closed loop, a scrubber, and a control mechanism for directing biogas to the scrubber and to a gas distributor. Methods of retrofitting a system for treating wastewater having sulfur and COD are disclosed.

A subsea fluid processing system which receives a wellstream flow. The subsea fluid processing system includes a pressure control device which regulates a pressure of the wellstream flow, a gas-liquid separator unit which receives the wellstream flow downstream of the pressure control device and which provides a liquid stream and a gas stream, a first membrane separator which receives the gas stream and which provides a retentate stream and a permeate stream, a compressor which receives the permeate stream and which provides a compressed permeate stream, and a discharge cooler which receives the compressed permeate stream and which provides a cooled compressed permeate stream for injection into a subsurface reservoir. A density of the cooled compressed permeate stream is higher than a density of the compressed permeate stream.

Disclosed are a heterogeneous zeolite membrane and a method of preparing the same, and more particularly a heterogeneous zeolite membrane that has CHA and DDR zeolite structures by growing seed particles into a crystal structure different from that of the zeolite membrane and can thus separate CO.sub.2/N.sub.2 and CO.sub.2/CH.sub.4 even under wet conditions, a method of preparing the same, and a method of capturing and removing carbon dioxide using the membrane.

The disclosure provides a method for producing a gas separation article, said gas separation article comprising: a gas separation membrane, optionally a support, and optionally an additional support said method comprising the steps of: a) providing a matrix comprising: a matrix material having a viscosity from 1 cP to 40000 cP, particles, said particles being free from functionalized carbon nanotubes, and optionally a solvent, b) contacting the matrix of step a) with a support comprising at least one side, said at least one side facing said matrix, thereby forming (i) a matrix side in contact with the support and (ii) a matrix side opposite the side in contact with the support, c) optionally contacting the matrix side opposite the side contacting the support with an additional support, d) subjecting said matrix being in contact with said support to one or more electric fields whereby the particles form particle groups in a plurality of substantially parallel planes, said particle groups in each of said plurality of substantially parallel planes being aligned substantially parallel with the one or more electric fields, e) fixating the matrix material so as to fixate the particle groups thereby forming a gas separation membrane, and f) optionally removing the support and/or the additional support.

The disclosure also provides a gas separation membrane obtainable by the aforementioned method as well as use thereof for separation of gases in a gas mixture.

Described herein are amorphous fluorinated copolymers produced by the polymerization of one or more fluorinated ring monomers and one or more fluorinated comonomers containing multiple ether oxygens. The copolymers are suitable in many high-technology applications, such as optical fibers, anti-reflection coatings, protective coatings, and gas separation membranes. In one aspect, the copolymers are useful is in the field of membrane-based gas separation processes. In one aspect, amorphous copolymer is produced by polymerizing (a) one or more fluorinated ring monomers in the amount of 1 mol % to 99.5 mol %, wherein the fluorinated ring monomer is at least a five membered ring and (b) a comonomer in the amount of from 0.5 mol % to 99 mol %, wherein the comonomer comprises a fluorinated compound with two or more ether oxygens.

A composite membrane suitable for separating a gas from a gas mixture comprising a selective layer coated on a support, wherein said selective layer comprises: a) a polymeric matrix comprising an amine polymer; b) a graphene oxide nanofiller; and c) a mobile carrier selected from an ionic liquid or an amino acid salt.

Disclosed is an apparatus and method for mixing transmission and separation of hydrogen gas and natural gas recovered based on pressure energy. The method includes: (1) hydrogen compressed natural gas is introduced into the pressure energy recovery system; (2) the low-pressure hydrogen compressed natural gas is introduced into the separation system; (3) the low-hydrogen natural gas and the, high concentration hydrogen gas are introduced into a first natural gas buffer tank and a first hydrogen gas buffer tank respectively; (4) the low-hydrogen natural gas and the high concentration hydrogen gas are introduced into the pressure boosting system; (5) the low-hydrogen natural gas and the high concentration hydrogen gas are respectively introduced into a natural gas user end. The method of the present invention is low in energy consumption, so as to realize pressure energy recovery, and energy consumption of hydrogen gas separation is greatly reduced.

A single compressor is used to separately compress permeate from cascaded first and second gas separation membrane-based separation units and residue from a fourth gas separation membrane-based separation unit in order to avoid too high a CO2 partial pressure in the compressed permeate. After the permeates from the first and second stages are compressed, the compressed stream is fed to a third gas separation membrane-based separation unit.

A process for purifying a gaseous feed stream of natural gas including methane, CO.sub.2 and heavy hydrocarbons including step a): cooling the gaseous feed stream in a heat exchanger; step b): introducing the cooled stream into a phase-separating chamber to produce a liquid stream depleted in methane and enriched in heavy hydrocarbons and a gaseous stream; step c): separating the gaseous stream obtained from step b) in a first membrane producing at least one CO.sub.2-enriched permeate stream and a residual stream enriched in methane; step d): introducing the residual stream obtained from step c) into a phase-separator to produce a liquid stream and a gaseous stream; step e): heating the gaseous stream obtained from step d) by introducing it into the heat exchanger used in step a) counter-currentwise with the feed stream thereby producing a gaseous stream depleted in CO.sub.2 and enriched in methane.

Described herein are articles for separating gases. The article includes an amorphous fluorinated copolymer containing, one or more types of fluorinated dioxolane ring monomers, and one or more types of fluorinated non-dioxolane ring monomers, optionally with crosslinking between the fluorinated copolymer chains. The copolymers of fluorinated dioxolane ring monomers and fluorinated non-dioxolane ring monomers show a large differential in the permeability of certain gases compared with other gases. The resulting polymer membranes have superior selectivity and reliability performance in certain gas separations compared with previous compositions known to the art. Methods for making and using the article described are also provided,