A method and apparatus for removing water from compressed air is disclosed. The method includes the steps of passing a stream of compressed air through a pressure swing adsorption (PSA) dryer. The dryer includes at least one vessel containing a desiccant material bound into pieces, for example tubes, using a polymer binder. The PSA dryer also has a control system for controlling the flow of the compressed air and switching between drying and purging modes. In particular the vessel and desiccant material contained therein are sized to produce a dew point suppression of less than 50° C.

The process of the present invention provides high recovery and low capital cost giving it an economic advantage over previously known purification processes. The present process has particular applicability to the purification of synthesis gases comprising at least hydrogen (H.sub.2), carbon monoxide (CO), methane (CH.sub.4), CO.sub.2, and H.sub.2O to obtain a gas stream including at least H.sub.2, CO, and CH.sub.4, that is substantially free of H.sub.2O and CO.sub.2. The process also has applicability to the purification of natural gases inclusive of at least CH.sub.4, N.sub.2, CO.sub.2, and H.sub.2O to produce a gas stream including at least CH.sub.4 and N.sub.2, but which is substantially free of H.sub.2O and CO.sub.2.

Disclosed are embodiments of a method of regenerating a desiccant in an off-line treater of a polyolefin production process. The method may include a heating phase followed by a cooling phase. The heating phase may involve use of a regenerating gas made from heating a treated a recycle stream of the polyolefin production process to regenerate desiccant in an off-line treater. The cooling phase may involve thermosyphoning the regenerating gas, nitrogen, an olefin-free diluent, or combinations thereof in a closed-convection loop of the off-line treater.

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.

A pressure swing adsorption process (PSA) comprising the following steps: feeding an input gas containing H.sub.2, CO.sub.2 and impurities through a CO.sub.2 adsorbent material in a pressure vessel under a high pressure; withdrawing a first H.sub.2-rich product gas due to adsorption of CO.sub.2 in the adsorbent material; setting the pressure to an intermediate pressure causing the adsorbent material release a second gas stream; passing a CO.sub.2-rich purge stream through the adsorbent material, obtaining a purge gas; setting the pressure to a sub-atmospheric low pressure, so that a CO.sub.2-rich product gas is released under vacuum by the adsorbent material; re-pressurizing the vessel to said high pressure; said steps being performed cyclically in a pressure vessel or in a plurality of parallel pressure vessels of a multiple vessel setup.

A system and method of pre-purification of a feed gas stream is provided that is particularly suitable for pre-purification of a feed air stream in cryogenic air separation unit. The disclosed pre-purification systems and methods are configured to remove substantially all of the hydrogen, carbon monoxide, water, and carbon dioxide impurities from a feed air stream and is particularly suitable for use in a high purity or ultra-high purity nitrogen plant. The pre-purification systems and methods preferably employ two or more separate layers of hopcalite catalyst with the successive layers of the hopcalite separated by a zeolite adsorbent layer that removes water and carbon dioxide produced in the hopcalite layers. Alternatively, the pre-purification systems and methods employ a hopcalite catalyst layer and a noble metal catalyst layer separated by a zeolite adsorbent layer that removes water and carbon dioxide produced in the hopcalite layer.

A temperature swing adsorption process for removing a target component from a gaseous mixture containing water and at least one side component, said process comprising: (a) at least one adsorption step, providing a target component-loaded adsorbent and at least one waste stream depleted of the target component; (b) a desorption step, comprising heating of the loaded adsorbent to a desorption temperature and providing a first output stream containing the desorbed target component; (c) a conditioning step; (d) at least one target component-releasing releasing step bringing the solid adsorbent to a temperature lower than said desorption temperature and providing at least one second output stream containing an amount of the target component and containing water; (e) separating water from said second output stream(s) and (f) subjecting the so obtained water-depleted stream(s) to said adsorption step or to at least one of said adsorption steps.

A temperature swing adsorption process for removing a target component from a gaseous mixture, the process being carried out in a plurality of reactors, wherein each reactor performs: (a) adsorption of the target component providing a loaded adsorbent and a waste stream; (b) heating of the loaded adsorbent and desorption of target component, providing an output stream; (c) cooling of the adsorbent; a rinse step (a1) before the heating (b), wherein the loaded adsorbent is contacted with a rinse stream containing the target component, producing a purge stream depleted of the target component; a purge step (b1) before the cooling (c), wherein the adsorbent is contacted with the purge stream provided by another reactor while performing the rinse step (a1), thus producing an output stream containing the target component, wherein the rinse stream comprises at least a portion of the output stream provided by another reactor while performing the purge step (b1).

Through the procedures of pretreatment, temperature swing adsorption (TSA) coarse desorption, pressure swing adsorption (PSA) purification and hydrogen purification, the hydrogenous waste gas from various procedures in the manufacturing process of semiconductor (especially silicon wafer), including the off-gas from chemical vapor deposition (CVD), doping (diffusion and ion implantation), photolithography and cleaning, the combusted and washed discharged gas of the off-gas in other procedures after field treatment and centralized treatment, or the hydrogenous waste gas entering the hydrogen discharge system are purified to meet the standard for the electronic grade hydrogen required for the manufacturing process of semiconductor, the recycling of hydrogen resources is realized, and the yield of hydrogen is greater than or equal to 70-85%. The present invention solves the technical difficulty the normal-pressure waste hydrogen recovered in the manufacturing process of semiconductor can't be returned to the manufacturing process of semiconductor for reuse.

Described herein are various embodiments of an oxygen concentrator system. In some embodiments, oxygen concentrator system includes one or more components that improve the useful lifetime of gas separation adsorbents.