Devices, methods, and systems for producing a concentrated feed stream and a diluted feed stream using a solute stream provided to the low pressure side of the semi-permeable membrane during a reverse osmosis process. The process includes providing a semipermeable membrane having a first side and a second side and introducing a first feed solution stream on the first side of the membrane and a second feed solution stream on the second side, wherein the osmotic pressure of the of the first feed solution stream is greater than or equal to the osmotic pressure of the second feed solution stream. The process further includes exerting hydrostatic pressure on the first side of the membrane such that solvent passes from the first side to the second side thereby producing a concentrated first feed solution stream and a diluted second feed solution stream. Devices and systems for performing the processes are provided.

A multi-stage polymeric membrane module system separates a gas, such as air, into components of high purity. In at least two of the stages, a portion of the retentate gas is directed into the low-pressure side of the module, to act as a sweep gas. The use of the sweep gas reduces the partial pressure of permeate gas on the low-pressure side of the membrane, and therefore improves the flow of permeate through the membrane. In a preferred embodiment, there are three modules. The output streams are taken from the retentate outlet of one module, and from the permeate outlet of another module. The output streams have very high purity, relative to the number of modules required, as compared with systems of the prior art.

Systems and processes for purifying and concentrating a liquid feed stream are disclosed. In the systems, the concentrated liquid output from the high pressure side of a reverse osmosis stage is used as the draw solution in the low pressure side of the reverse osmosis stage in a configuration called osmotically assisted reverse osmosis. This reduces the osmotic pressure differential across the membrane, permitting high solute concentrations to be obtained, hastening the purification of the liquid. Reduced system pressures are also obtained by arranging multiple osmotically assisted reverse osmosis stages in a cross-current arrangement. Overall system energy consumption is reduced compared to conventional thermal processes for high concentration streams.

Equipment, systems, processes and techniques for conducting processing of solutions are described. The techniques can be applied to provide diluted solution (i.e. purified solvent), concentrate solution or each. A variety of specific equipment, example systems and processes are depicted and described.

A process for separating solvent from a feed solution, said process comprising contacting the feed solution with one side of a semi-permeable membrane, applying hydraulic pressure to the feed solution, such that solvent from the feed solution flows through the membrane by reverse osmosis to provide a permeate solution on the permeate-side of the membrane, separating solvent from the permeate solution to provide a stream comprising the solvent and a residual solution having an increased osmotic pressure than the permeate solution, and recycling the residual solution to the permeate-side of the semi-permeable membrane, whereby the osmotic pressure on the permeate-side of the semi-permeable membrane is lower than the osmotic pressure of the feed solution.

An example water purification system includes a forward osmosis module, a reverse osmosis module, a pump powered by an electric motor, and a pressure sensor. The forward osmosis module may receive a feed stream and a draw stream, and may produce an intermediate product stream. The intermediate product stream may be pressurized by a pump and provided to the reverse osmosis module. The reverse osmosis module may generate a product stream and return the draw stream to the forward osmosis module. The pressure sensor may monitor the pressure of the intermediate product stream, and the pressure may be used to determine the speed of the electric motor.

Systems and processes for purifying and concentrating a liquid feed stream are disclosed. In the systems, the concentrated liquid output from the high pressure side of a reverse osmosis stage is used as the draw solution in the low pressure side of the reverse osmosis stage in a configuration called osmotically assisted reverse osmosis. This reduces the osmotic pressure differential across the membrane, permitting high solute concentrations to be obtained, hastening the purification of the liquid. Reduced system pressures are also obtained by arranging multiple osmotically assisted reverse osmosis stages in a cross-current arrangement. Overall system energy consumption is reduced compared to conventional thermal processes for high concentration streams.

Systems and processes for purifying and concentrating a liquid feed stream are disclosed. In the systems, the concentrated liquid output from the high pressure side of a reverse osmosis stage is used as the draw solution in the low pressure side of the reverse osmosis stage in a configuration called osmotically assisted reverse osmosis. This reduces the osmotic pressure differential across the membrane, permitting high solute concentrations to be obtained, hastening the purification of the liquid. Reduced system pressures are also obtained by arranging multiple osmotically assisted reverse osmosis stages in a cross-current arrangement. Overall system energy consumption is reduced compared to conventional thermal processes for high concentration streams.

Equipment, systems, processes and techniques for conducting processing of solutions are described. The techniques can be applied to provide diluted solution (i.e. purified solvent), concentrate solution or each. A variety of specific equipment, example systems and processes are depicted and described.

Equipment, systems, processes and techniques for conducting processing of solutions are described. The techniques can be applied to provide diluted solution (i.e. purified solvent), concentrate solution or each. A variety of specific equipment, example systems and processes are depicted and described.