A gas separation system includes: first, second, and third gas separation membrane units. A first retentate gas line connects a retentate gas discharge port of the first unit and gas inlet port of the second unit. A first permeate gas line connects a permeate gas discharge port of the first unit and gas inlet port of the third unit. A feed gas mixture supply line is connected to a gas inlet port of the first unit, and provided with first compression elements. The first permeate gas line is provided with second compression elements. The permeate gas discharge port of the second unit is connected by a second permeate gas line to the suction side of the first compression elements in the feed gas mixture supply line. A retentate gas discharge port of the third unit is connected by a third retentate gas line to the first retentate gas line.

A water treatment device includes a primary unit having a plurality of primary elements as reverse osmosis membrane devices disposed in parallel with each other to separate water to be treated into primary condensed water and fresh water; a pump which feeds the water to be treated from the upstream side of the primary unit to the primary unit; a secondary unit having secondary elements which are provided to be fewer in number than the primary elements and separate the primary condensed water into secondary condensed water and fresh water; a sub-element which separates one of the water to be treated and the primary condensed water; and a mode switching unit which switches the sub-element between a primary mode of being used as the primary element in the primary unit and a secondary mode of being used as the secondary element in the secondary unit.

A filtration system includes at least one spiral wound first filter section in fluid communication with at least one spiral wound second filter section. The first and second filter sections include: (i) a filtration membrane; (ii) a feed spacer located adjacent the filtration membrane and defining a feed flow channel; and (iii) a permeate spacer located adjacent the filtration membrane and defining a permeate flow channel. A thickness of the feed flow channel in the first filter section is different than a thickness of the feed flow channel in the second filter section, and/or an effective volume of the first filter section is different than an effective volume of the second filter section. A method of filtering a feed flow is also disclosed.

Concentration control in filtration systems and associated methods are generally described. Streams originating from upstream filters and having similar concentrations of a target minor component and/or similar osmotic pressures can be mixed and subsequently filtered within additional filters. Certain embodiments comprise recycling an output stream produced by a filter to a filter feed stream, wherein the output stream and the filter feed stream have similar concentrations of a target minor component and/or similar osmotic pressures. Such strategic mixing and/or recycling can reduce the amount of energy and/or the amount of filtration medium surface area required to achieve a desired concentration of the target minor component in a final product stream.

A water treatment device (1) includes a primary unit (U1) having a plurality of primary elements (E1) as reverse osmosis membrane devices disposed in parallel to each other to separate water to be treated (SW) supplied from an upstream side into primary condensed water (CW1) and fresh water (FW1); a pump (P) which feeds the water to be treated from the upstream side of the primary unit to supply the water to be treated to the primary unit; a secondary unit (U2) having secondary elements (E2) as reverse osmosis membrane devices, the secondary elements being provided in smaller number than the primary elements and disposed in parallel to each other to separate the primary condensed water into secondary condensed water (CW2) and fresh water (FW2); and a reflux unit (2) which refluxes a part of the secondary condensed water between the primary unit and the secondary unit.

A system and method for switching between flows of water solutions passed in groups of blocks of membrane pressure vessels arranged in parallel in a tapered flow system, wherein the system comprises a system inlet feed line, a system outlet flow line, high pressure booster pumps configured to provide a high pressure feed stream to the system; blocks of membrane pressure vessels arrayed in parallel, and a first and second bypass line each parallel to said blocks.

The invention relates to a process for separating a composition of matter with the aid of a membrane cascade having at least two stages, in which a separation is effected in each stage at at least one membrane at a separation temperature set for the particular stage. The invention further relates to a corresponding membrane cascade, to the use of said membrane cascade for catalyst separation from homogeneously catalyzed mixtures, and to a process for hydroformylation, in which the catalyst is separated by means of a membrane cascade. The problem addressed thereby is that of specifying a membrane-based process for separating compositions of matter, which has a minimum membrane area requirement and nevertheless fulfills the separation task and separation performance required. This problem is solved by the use of a membrane cascade with falling separation temperature.

Provided are water treatment systems and methods of treating water that include separating boron and concentrating lithium. For example, described are water treatment systems comprising: a first phase comprising a first plurality of electrodialysis units configured to separate boron from a feed stream, and a second phase comprising a second plurality of electrodialysis units, wherein the feed stream of at least one electrodialysis unit of the second plurality of electrodialysis units comprises an outlet brine stream of at least one electrodialysis unit of the first plurality of electrodialysis units, and wherein the second plurality of electrodialysis units are configured to produce a product brine stream achieving 90-99% lithium recovery.

The present invention relates to a method and system for reducing water consumption in a membrane dealcoholization process. The system comprises a dealcoholization section and a polishing section, where the polishing section comprises one or more membrane polishing units with recirculation of streams.

A process for purifying a urea-containing aqueous stream, such as the aqueous stream from the recovery section of a urea plant, comprising a step of removing biuret from the urea-containing stream by reverse osmosis in one or more reverse osmosis stages.