An oxygen concentrator is provided with a controller for recovering an oxygen concentration to a level suitable for treatment in a short period of time by selecting an optimum purge time corresponding to the deterioration state of an adsorbent. The judgment of moisture-absorption deterioration is performed when the detected value of the oxygen concentration sensor is equal to or less than a control value of the oxygen concentration in the oxygen-enriched gas and the detected value of the pressure sensor is equal to or more than an adsorption pressure at which the oxygen concentration increases significantly before and after the control to reduce the purge time, and control of reducing a time for the purge step shorter than a preset time is performed.

The invention relates to an internal combustion engine that comprises a first Brayton cycle comprising a mixed ionic-electronic conducting (MIEC) membrane that separates the O.sub.2 from the air such that the suctioned air current is free from N.sub.2; a second Brayton cycle combined in a binary manner with the first Brayton cycle and nested with a cycle selected from an Otto cycle and a diesel cycle performed by means of oxy-combustion. The second Brayton cycle transmits mechanical energy and thermal energy from exhaust gases to the first Brayton cycle. The first Brayton cycle provides to the second Brayton cycle compressed O.sub.2 from the MIEC membrane. By means of the present engine, the NOx emission into the atmosphere is prevented by the separation of N.sub.2 in the MIEC membrane.

The invention provides a process of purifying a fluid useful in a manufacturing process, particularly in the manufacture of silicon wafers, by removing one or more impurities; and apparatus for use in the process.

In a helium purification process, a stream containing at least 10% of helium, at least 10% of nitrogen in addition to hydrogen and methane is separated to form a helium-enriched stream containing hydrogen, a first stream enriched in nitrogen and in methane and a second stream enriched in nitrogen and in methane, the helium-enriched stream is treated to produce a helium-rich product and a residual gas containing water, the residual gas is treated by adsorption (TSA) to remove the water and the regeneration gas from the adsorption is sent to a combustion unit (O).

The invention relates to a method for separating gases which comprises: a first step in which a gas fuel stream comprising combustible substances that produce gas products when oxidised, and an oxygen-rich inlet stream are passed through at least two modules of oxygen-separating ceramic membranes, such that the two streams come into contact through the membranes and exchange heat; a second step of selective diffusion of oxygen from the oxygen-rich stream to the fuel stream, such that the outlet streams from the membrane modules are an oxygen-depleted or completely oxygen-free stream and a partially or completely oxidised stream; and a third step of recovery of at least two separate outlet streams of at least two gases selected from oxygen, nitrogen, carbon dioxide and hydrogen.

A method for extending useful life of a sorbent for purifying a gas by sorption of an impurity is provided. The method generating a electrical discharge within the gas to obtain a spectral emission representative of a concentration of the impurity. The method also includes monitoring the concentration of the impurity according to the spectral emission. The method also includes lowering the concentration of the impurity by conversion of at least a portion of the impurity into a secondary impurity having a greater affinity to the sorbent than the impurity. The method also includes comparing the concentration of the impurity to a polluting concentration and managing the sorption of the gas onto the sorbent according to the comparison.

A process for recovery of helium from one or more than one helium-containing off-gas streams comprises preconditioning off-gas through a multi-stage preconditioning device, cryogenically separating a helium-enriched gas fraction from the preconditioned off-gas received from the preconditioning device a cryogenic separation device, and purifying the helium-enriched gas fraction received from the cryogenic separation device using a purification device so as to obtain purified helium gas with a higher helium content than the helium-enriched gas.

Systems and methods for producing oxygen enriched air using vacuum pressure swing adsorption (VPSA) are disclosed. In one implementation, an oxygen concentrator includes a canister system having at least one canister, a pumping system having at least one motor-controlled pump, a set of valves pneumatically coupling the canister system and the pumping system, and a controller. The canister is configured to receive a gas separation adsorbent. The controller is configured to control operation of the pumping system and the set of valves to: selectively pneumatically couple the motor-controlled pump and the canister so as to pressurize the canister and selectively pneumatically couple the motor-controlled pump and the canister so as to evacuate the canister.

A method and system for purification of helium and CO.sub.2 from a stream containing at least Helium, CO2, nitrogen or methane uses a combination of cryogenic, membrane and adsorption technologies.

An apparatus and a method for producing carbon, oxygen and optionally nitrogen from treated flue gases are provided. The apparatus provides a thermo-dielectric-electric field that splits molecules of carbon dioxide and carbon monoxide into carbon and oxygen and nitrogen oxides into nitrogen and oxygen. The carbon is recovered in a variety of solid forms, and oxygen and nitrogen are recovered as gases.