An oxygen production unit is provided. The oxygen production unit, in various embodiments, includes a separation unit configured to separate oxygen from nitrogen in received gaseous particles; a control unit configured to control an amount of the separated oxygen to be released to a user of the oxygen production unit, and a nitrogen release unit configured to facilitate release of the separated nitrogen within oxygen production unit and/or into an environment where the oxygen production unit is located. The oxygen production unit in those embodiments can automatically determine an amount of oxygen to be produced and/or delivered to a user; a control and facilitate release of nitrogen into the environment to enhance safety; to facilitate swapping of nitrogen piece(s) in the oxygen production unit to prolong a lifetime of the oxygen production unit, and/or achieve any other benefits.

Disclosed is a method for purifying a main gas, in particular helium, from a source gas stream comprising the main gas, a main impurity, in particular nitrogen, and optionally another, secondary impurity, in particular oxygen, the method comprising a step of partial condensation of the gas stream in order to extract therefrom impurities in liquid form, in particular the main impurity, and to produce a gas stream enriched with main gas, characterized in that the method comprises, before the partial condensation step, a step of injecting into the gas stream a compound in which the main impurity of the gas to be treated is soluble and having a saturation vapor pressure lower than the saturation vapor pressure of the main impurity.

Novel methods for pretreating a rare-gas-containing stream exiting an etch chamber followed by recovering the rare gas from the pre-treated, rare-gas containing stream are disclosed. More particularly, the invention relates to the pretreatment and recovery of a rare gas, such as xenon or krypton, from a nitrogen-based exhaust stream with specific gaseous impurities generated during an etch process that is performed as part of a semiconductor fabrication process.

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.

An oxygen concentration system may comprise a pressure sensor, a movement sensor, and a controller configured to use one or more pressure signals obtained from the pressure sensor and a movement signal obtained from the movement sensor to determine when to release a bolus of oxygen enriched air. In some implementations, the controller may adjust a trigger threshold based on an initial pressure signal obtained from the pressure sensor and the movement signal obtained from the movement sensor. In some implementations, the controller may adjust a pressure signal obtained from the pressure sensor based on the movement signal obtained from the movement sensor. In some implementations, the controller may detect a potential onset of inhalation from a pressure signal obtained from the pressure sensor and determine whether to verify the potential onset of inhalation based on the movement signal obtained from the movement sensor.

Novel methods for pretreating a rare-gas-containing stream exiting an etch chamber followed by recovering the rare gas from the pre-treated, rare-gas containing stream are disclosed. More particularly, the invention relates to the pretreatment and recovery of a rare gas, such as xenon or krypton, from a nitrogen-based exhaust stream with specific gaseous impurities generated during an etch process that is performed as part of a semiconductor fabrication process.

A method for recovering helium from a feed gas mixture comprising helium, carbon dioxide and at least one of methane and nitrogen, and wherein at least a part of the feed gas mixture is subjected to a separation sequence including a membrane-based separation and an adsorption-based separation forming a helium product, wherein the the membrane based separation is performed using a first membrane separation step and a second membrane separation step, the membrane based separation and the separation sequence includes no further membrane separation steps, the adsorption based separation is performed using a pressure swing adsorption step, at least a part of the feed gas mixture is subjected to the first membrane separation step forming a first retentate and a first permeate. A corresponding arrangement is also provided.

Novel methods for pretreating a rare-gas-containing stream exiting an etch chamber followed by recovering the rare gas from the pre-treated, rare-gas containing stream are disclosed. More particularly, the invention relates to the pretreatment and recovery of a rare gas, such as xenon or krypton, from a nitrogen-based exhaust stream with specific gaseous impurities generated during an etch process that is performed as part of a semiconductor fabrication process.

Systems and methods are provided for separating oxygen from air using a sorption/desorption cycle that includes a reduced or minimized difference between the maximum and minimum pressures involved in the sorption/desorption cycle. The reduced or minimized difference in pressures can be achieved in part by using valves that can allow for commercial scale flow rates while avoiding large pressure drops for flows passing through the valves. A rotary wheel adsorbent is an example of a system that can allow for a sorption/desorption cycle with reduced and/or minimized pressure drops across valves associated with the process. Stationary adsorbent beds can also be used in combination with commercially available valves that have reduced and/or minimized pressure drops.

The present invention relates to spherical agglomerates based on zeolite(s) and clay(s), having controlled size and morphology, in particular a size of less than or equal to 600 μm, very good sphericity, and a high content of zeolitic material, to the process for the production thereof. These agglomerates are particularly suitable for uses in gas-phase and/or liquid-phase adsorption processes.