The present invention relates to a method for purifying hydrogen peroxide, and more particularly, to a method including purifying a crude product of hydrogen peroxide using a primary purification system, and purifying a primarily purified hydrogen peroxide solution using a secondary purification system. One of the primary purification system and the secondary purification system includes an electrodeionization system, and the other one of the primary purification system and the secondary purification system includes at least one from among a distillation system, a resin system, a reverse osmosis system, and a combination system thereof.

Described herein are membrane processes for separating CO.sub.2 from flue gas. An exemplary process involves passing a fluid stream including the flue gas across a membrane permeable to CO.sub.2 and H.sub.2O, removing treated gas from a feed side of the membrane that has less CO.sub.2 than the flue gas, and removing permeate from a permeate side of the membrane comprising CO.sub.2 and H.sub.2O. Suitably, the permeate is removed at a sub-atmospheric vacuum pressure. The permeate is then cooled to remove at least some of the H.sub.2O from the permeate and form a smaller volume of H.sub.2O-depleted, CO.sub.2 enriched permeate.

Described herein are membrane processes for separating CO.sub.2 from flue gas. An exemplary process involves passing a fluid stream including the flue gas across a membrane permeable to CO.sub.2 and H.sub.2O, removing treated gas from a feed side of the membrane that has less CO.sub.2 than the flue gas, and removing permeate from a permeate side of the membrane comprising CO.sub.2 and H.sub.2O. Suitably, the permeate is removed at a sub-atmospheric vacuum pressure. The permeate is then cooled to remove at least some of the H.sub.2O from the permeate and form a smaller volume of H.sub.2O-depleted, CO.sub.2 enriched permeate.

A process and system to control the final product quality in a system for separating olefins and paraffins in a membrane system. A small finishing membrane stage is added to an existing membrane system that takes a slip stream from the product, purifies it to a very high concentration of propylene and blends it back into the product stream.

A flue gas extraction system provides extraction, collection, cooling, enriching and distributing flue gas from a vent stack of a stationary flue gas generator to carbon dioxide consuming crops, orchards, and other photosynthetic organisms. The collected flue gas is processed through the system to achieve optimal temperature, pressure, flowrate, water content and carbon dioxide concentration for application to plants for increasing plant productivity and sequestering the carbon dioxide. The gas distribution network may have one or more membrane modules which receive a low pressure gas mixture, where the membrane modules are utilized to enrich the CO2 concentration and to separate out a nitrogen rich component from the flue gas. Application of carbon dioxide may be supplemented by providing additional components to the plants which maintain a level of fertilization and irrigation suitable for the increased biomass and water utilization efficiency of the plants resulting from the increased intake of carbon dioxide.

Processes and systems for recovering hydrogen may include feeding a gas stream, comprising hydrogen and additional gases, to a pressure swing adsorption (PSA) system and feeding a membrane permeate stream comprising hydrogen to the PSA system. In the PSA system, a portion of the hydrogen may be separated from the additional gases to recover a hydrogen product stream and a PSA tail gas stream comprising unseparated hydrogen and the additional gases. The PSA tail gas stream may be fed to a membrane separation unit for separating hydrogen from the additional gases and to recover (i) the membrane permeate stream comprising hydrogen fed to the PSA system and (ii) a membrane tail gas stream comprising the additional gases. Embodiments herein may additionally include a refrigeration system for partially condensing one or both of the feed gas stream and the PSA tail gas stream, enhancing the efficiency of the membrane separation unit.

A membrane distillation apparatus includes a housing and an impeller. The housing includes a hot medium compartment, a cold medium compartment, a permeate gap compartment, a membrane, and a thermally conductive plate. The hot medium compartment includes a hot medium inlet configured to receive a hot medium stream including water. The cold medium compartment includes a cold medium inlet configured to receive a cold medium stream. The membrane defines pores that are sized to allow water vapor originating from the hot medium stream to pass from the hot medium compartment through the membrane to the permeate gap compartment. The thermally conductive plate and the cold medium stream are cooperatively configured to condense the water vapor from the hot medium stream. The permeate gap compartment includes a permeate outlet configured to discharge the condensed water vapor. The impeller is disposed within the permeate gap compartment.

The present disclosure provides a system for refining long chain dicarboxylic acid, comprising: a first membrane filtration unit, for a first membrane filtration of a long chain dicarboxylic acid fermentation broth or a treated liquid therefrom; a first decolorization unit, for carrying out a first decolorization treatment to the filtrate obtained after the membrane filtration; a first acidification/crystallization unit, for carrying out a first acidification/crystallization of a filtrate obtained after the membrane filtration to give a solid-liquid mixture; a first separation unit, for a solid-liquid separation of the solid-liquid mixture; a drying unit, for drying the solid separated by the separation unit to give a first solid. By using the refining system according to the present disclosure, the purity of the obtained product is high, and the disadvantages such as poor quality of the product obtained by crystallization from a solvent and environment pollution caused by a solvent can be overcome.

The present invention relates to a low-temperature membrane separation device and method for capturing carbon dioxide at a high concentration, in which a gas mixture is passed through a membrane unit to thus separate carbon dioxide. The membrane unit includes a membrane for capturing carbon dioxide and is connected to a feed gas line, a retentate gas line and a permeate gas line. The method includes a first separation step of passing the gas mixture through a first membrane unit and a second separation step of passing the permeation gas, which is discharged to the permeate gas line connected to the first membrane unit, through a second membrane unit. The second separation step is performed at a temperature that is lower than a temperature at which the first separation step is performed.

A desalination apparatus is disclosed which comprises: a first tank for storing seawater to be desalinated; a second tank comprising a hydrophobic membrane desalination module operable to absorb only fresh water vapors and reject salt components when the seawater is heated to a first predetermined temperature that changes the seawater into the fresh water vapors, and wherein the hydrophobic membrane desalination module is configured to continuously allow the distilled fresh water to make contact with the fresh water vapors within its interior hollow volume; and a third tank, in fluid communication with the second tank, configured to cause the fresh water vapors from the hydrophobic membrane desalination module to be condensed into liquid fresh water by continuously allowing the fresh water vapors to make contact with a coolant water at a second temperature.