A preparation method of separation membrane is provided. First, a polyimide composition including a dissolvable polyimide, a crosslinking agent, and a solvent is provided. The dissolvable polyimide is represented by formula 1:

##STR00001## wherein B is a tetravalent organic group derived from a tetracarboxylic dianhydride containing aromatic group, A is a divalent organic group derived from a diamine containing aromatic group, A is a divalent organic group derived from a diamine containing aromatic group and carboxylic acid group, and 0.1X0.9. The crosslinking agent is an aziridine crosslinking agent, an isocyanate crosslinking agent, an epoxy crosslinking agent, a diamine crosslinking agent, or a triamine crosslinking agent. A crosslinking process is performed on the polyimide composition. The polyimide composition which has been subjected to the crosslinking process is coated on a substrate to form a polyimide membrane. A dry phase inversion process is performed on the polyimide membrane.

The present invention aims to improve the production capacity of alcohol in a method of producing high concentration alcohol using a distillation column and an adsorption-desorption column. The method is a method of producing high concentration alcohol by dehydration of a water-alcohol mixture, including: a distillation step of introducing a water-alcohol mixture into a distillation column to obtain crude alcohol; and an adsorption-desorption step of introducing a part of the crude alcohol into an adsorption-desorption column to obtain high concentration alcohol; wherein a further part of the crude alcohol is introduced into a dehydration apparatus to obtain high concentration alcohol.

An air-impermeable water vapor transport membrane comprises an active layer on a microporous polymeric substrate. The active layer comprises a polyethylene-oxide containing copolymer and a polar protic solvent in an amount of about 3% to about 100% of copolymer weight in the active layer. Molecules of the protic solvent are bonded to the copolymer. The polar protic solvent reduces temperature-dependent variability in the water-vapor permeability of the membrane.

A preparation method of separation membrane is provided. First, a polyimide composition including a dissolvable polyimide, a crosslinking agent, and a solvent is provided. The dissolvable polyimide is represented by formula 1: ##STR00001## wherein B is a tetravalent organic group derived from a tetracarboxylic dianhydride containing aromatic group, A is a divalent organic group derived from a diamine containing aromatic group, A is a divalent organic group derived from a diamine containing aromatic group and carboxylic acid group, and 0.1X0.9. The crosslinking agent is an aziridine crosslinking agent, an isocyanate crosslinking agent, an epoxy crosslinking agent, a diamine crosslinking agent, or a triamine crosslinking agent. A crosslinking process is performed on the polyimide composition. The polyimide composition which has been subjected to the crosslinking process is coated on a substrate to form a polyimide membrane. A dry phase inversion process is performed on the polyimide membrane.

A preparation method of separation membrane is provided. First, a polyimide composition including a dissolvable polyimide, a crosslinking agent and a solvent is provided. The dissolvable polyimide is represented by formula 1:

##STR00001##

wherein B is a tetravalent organic group derived from a tetracarboxylic dianhydride containing aromatic group, A is a divalent organic group derived from a diamine containing aromatic group, A is a divalent organic group derived from a diamine containing aromatic group and carboxylic acid group, and 0.1X0.9. The crosslinking agent is an aziridine crosslinking agent, an isocyanate crosslinking agent, an epoxy crosslinking agent, a diamine crosslinking agent, or a triamine crosslinking agent. A crosslinking process is performed on the polyimide composition. The polyimide composition which has been subjected to the crosslinking process is coated on a substrate to form a polyimide membrane. A wet phase inversion process is performed on the polyimide membrane.

An inert gas generating system includes a source of a liquid hydrocarbon fuel, and a fractioning unit configured to receive a portion of the liquid hydrocarbon fuel from the source. The fractioning unit includes a perm-selective membrane configured to separate the portion of the liquid hydrocarbon fuel into substantially sulfur-free vapors and a sulfur-containing remainder. The system further includes a catalytic oxidation unit configured to receive and react the substantially sulfur-free vapors to produce an inert gas.

A preparation method of separation membrane is provided. First, a polyimide composition including a dissolvable polyimide, a crosslinking agent and a solvent is provided. The dissolvable polyimide is represented by formula 1: ##STR00001## wherein B is a tetravalent organic group derived from a tetracarboxylic dianhydride containing aromatic group, A is a divalent organic group derived from a diamine containing aromatic group, A is a divalent organic group derived from a diamine containing aromatic group and carboxylic acid group, and 0.1X0.9. The crosslinking agent is an aziridine crosslinking agent, an isocyanate crosslinking agent, an epoxy crosslinking agent, a diamine crosslinking agent, or a triamine crosslinking agent. A crosslinking process is performed on the polyimide composition. The polyimide composition which has been subjected to the crosslinking process is coated on a substrate to form a polyimide membrane. A wet phase inversion process is performed on the polyimide membrane.

A process is provided of making facilitated transport membrane comprising a relatively hydrophilic, very small pore, nanoporous support membrane, a hydrophilic polymer inside the very small nanopores on the skin layer surface of the support membrane, a thin, nonporous, hydrophilic polymer layer coated on the surface of the support membrane, and metal salts incorporated in the hydrophilic polymer layer coated on the surface of the support membrane and the hydrophilic polymer inside the very small nanopores. In addition, the process provides a new method of making facilitated transport membrane spiral wound elements or hollow fiber modules for olefin/paraffin separations, particularly for C3=/C3 and C2=/C2 separations.

The present disclosure provides processes and systems for dehydrating a byproduct stream in ethanol production. In one embodiment, a feed mixture is distilled with one or more distillation units to remove at least a portion of the water, and form a first byproduct stream. The first byproduct stream is contacted with a molecular sieve unit, thereby forming a product stream. The molecular sieve unit is cyclically contacted with at least a portion of the product stream to regenerate the molecular sieve unit and form one or more regenerate streams. A second byproduct stream including at least one of (1) the regenerate streams and (2) at least a portion of the fusel oil stream is contacted with a separation system, thereby forming a permeate and a retentate. At least a portion of the retentate is forwarded into the product stream.

An air-impermeable water vapor transport membrane comprises an active layer on a microporous polymeric substrate. The active layer comprises a polyethylene-oxide containing copolymer and a polar protic solvent in an amount of about 3% to about 100% of copolymer weight in the active layer. Molecules of the protic solvent are bonded to the copolymer. The polar protic solvent reduces temperature-dependent variability in the water-vapor permeability of the membrane.