Abstract: A process for hydrogen recovery from refinery gas system comprising supplying the refinery gas to an inlet manifold fluidly coupled to a conditioning stage, the conditioning stage comprising a reactor having a reforming catalyst deposited on an ultra-short-channel-length metal substrate; supplying oxidant to the conditioning stage via the inlet manifold; supplying steam from a steam generator to the conditioning stage via the inlet , manifold; reacting the refinery gas in the conditioning stage; and discharging a product through a discharge outlet fluidly coupled to the conditioning stage, the discharge outlet configured to flow the product for use by a downstream reformer. The process allows to either increase the H2 production rate or lower the firing rate while maintaining a constant H2 production rate for the downstream steam reformer, independent of the feed compositional variability of the refinery or still gas.

Abstract: The present invention relates to a device for isolating and cleaning contaminated components comprising a chamber, an entrance door through which components to be isolated and cleaned are introducible into the chamber, means configured to deliver washing solution into the chamber and onto the components to be cleaned, a drying system configured to dry the chamber as well as its content, wherein the device further comprises an exhaust filter system attached to the air exhaust of the chamber, the exhaust filter system comprising a pipe, at least one filter and a blower, the exhaust filter system being configured to be able to bring the chamber under a pressure lower than atmospheric pressure by means of the blower all the time the chamber is closed. The present invention also relates to a corresponding method for isolating and cleaning contaminated components with the aforementioned device.

Abstract: A method for fabrication of an hydrogen-permeable membrane, comprising forming an alloy of a target composition and structure from powders by mechanically alloying; and forming a membrane from the alloy of the target composition and structure.

Abstract: Gas purifiers for removal of active and low activity contaminants from gas streams with the help of metal powder sorbent on the basis of binary, ternary and multicomponent alloys. The total mole fraction x of reactive metals like Li, Ca, Sr, Ba and others is in the range of 0.5?x?1.0.

Abstract: A hydrogen supply system for supplying hydrogen comprises a reaction unit for producing a hydrogen-containing gas by a dehydrogenation reaction of a starting material, a heat supply unit for supplying heat to the reaction unit, a removal unit for removing through membrane separation a dehydrogenation product from the hydrogen-containing gas produced by the reaction unit, and a first off-gas line for supplying a part or whole of an off-gas from the removal unit to the reaction unit.

Abstract: Apparatus and methods to perform hydrogen/deuterium exchange using semipermeable membranes are described. The system has two channels separated by a semipermeable membrane. One channel comprises a flow carrying the analyte of interest, and the second channel comprises a solution comprising a deuterated solvent (e.g. deuterium oxide). The system does not require an external electric field gradient across the membrane to perform the hydrogen-deuterium exchange procedure. The present invention facilitates sample and reagent handling as well as simplifies manufacture of devices and/or instrumentation related to deuterium exchange. Further described is a chemical analyzation device for analyzing chemical compositions and/or compounds, and a method for analyzing chemical compounds and a computer program product for inducing a computer to perform steps in the method.

Abstract: A getter device containing a combination of getter materials is described. The device has a mixture of cerium oxide, copper oxide and metallic palladium for the removal of hydrogen and carbon monoxide in vacuum applications, particularly suitable to be used in vacuum insulation applications. This combination of getter materials is preferably added to powders of other getter materials such as alkali metals hydroxides and desiccant materials that are effective for maintaining the vacuum in thermal insulation systems.

Abstract: Hydrogen and carbon monoxide impurities are removed from a dry gas comprising the impurities, wherein the dry gas is at least substantially free of carbon dioxide, by passing the dry gas with sufficient residence time, e.g. at least 1.5 s, through a layer of catalyst comprising a mixture of manganese oxide and copper oxide. The use of expensive noble metal catalysts to remove hydrogen may thereby be avoided. In addition, regeneration of the catalyst using oxygen-containing regeneration gas does not reduce the effectiveness of the catalyst.

Abstract: Systems and Methods for manufacturing ZPGM catalysts systems that may allow the prevention of formation or the conversion of corrosion causing compounds, such as hexavalent chromium compounds, within ZPGM catalyst systems are disclosed. ZPGM catalysts systems, may include metallic substrate, which may include alloys of iron and chromium, a washcoat and an overcoat. Disclosed manufacturing processes may include a thermal decomposition of hexavalent chromium compounds which may allow the decomposition of such compounds into trivalent chromium compounds, and may also produce metallic catalyst, such as silver.

Abstract: There are provided methods capable of easily and efficiently recovering and recycling ammonia from exhaust gas containing a small amount of ammonia, the exhaust gas being exhausted from a production process of a gallium nitride compound semiconductor. The method of recovering ammonia includes filtering exhaust gas containing ammonia, hydrogen, nitrogen, and a solid compound with a filter to remove the solid compound from the exhaust gas; pressurizing and cooling the filtered exhaust gas with a heat pump to liquefy ammonia contained in the filtered exhaust gas; and separating liquefied ammonia from hydrogen and nitrogen to recover liquefied ammonia. The method of recycling ammonia includes evaporating recovered liquid ammonia; mixing the evaporated ammonia with another crude ammonia to obtain mixed gas; purifying the mixed gas; and supplying the purified gas to the production process of a gallium nitride compound semiconductor.

Abstract: Getter alloys particularly suitable for hydrogen sorption are described. The getter alloys include a first element consisting of yttrium or a yttrium equivalent mixture, the first element forming at least 30% by atoms of the alloy. A method for removing hydrogen from devices which are sensitive to the presence thereof and hydrogen-sensitive devices which contain the described getter alloys are also described.

Abstract: A process of treating hydrogen gas liberated from the acid or alkaline dissolution of a metal is provided. The process comprises a step of passing the liberated hydrogen gas through a reactor containing an oxidizing agent for oxidation of the hydrogen gas into water, followed by a step of regenerating the oxidizing agent. Also provided is an apparatus for carrying out the process, the apparatus comprising a reactor containing the oxidizing agent, wherein the reactor is at least partially immersed in an alumina bath.

Abstract: The inventive stage system for producing hydrogen consists of at least two upstream/downstream stages, respectively, each of which comprises, optionally, a catalytic reactor (C1 to C5) followed by a separator comprising a space (E1 to E4) for circulation of a gaseous mixture contacting at least one oxygen extracting membrane and a hydrogen collecting space, wherein the reactor (C1) of the upstream stage is connected to a reaction gaseous mixture source, the circulation stage (E1) of the upstream stage separator is connected to the reactor (C2) of the downstream stage and the spaces for extracting/collecting oxygen from two separators are connected to a hydrogen collecting circuit (TC, 8) which is common for two stages.

Abstract: Process for working up an exhaust gas from a system for producing hydroxylamine or hydroxylammonium salts by catalytic reduction of nitrogen monoxide with hydrogen, the exhaust gas containing nitrogen monoxide, hydrogen, dinitrogen monoxide, nitrogen and ammonia. At least some of the hydrogen present in the exhaust gas is separated off from the exhaust gas by means of a gas-tight membrane-electrode assembly which comprises at least one selectively proton-conducting membrane, a retentate side, a permeate side, and, on each side of the membrane, at least one electrode catalyst, wherein, on the retentate side of the membrane, at least some of the hydrogen is oxidized to protons at the anode catalyst and the protons, after crossing the membrane, are, on the permeate side, at the cathode catalyst according to (I) reduced to hydrogen and/or (II) reacted with oxygen to form water, the oxygen originating from an oxygen-containing stream which is contacted with the permeate side.

Abstract: The invention described herein relates to a novel process for reducing the carbon dioxide emissions from a coal and/or biomass liquefaction facility by utilizing a steam methane reformer unit in the complex designed to produce additional hydrogen which can be thereafter utilized in the process, as required for the plant fired heaters (including the SMR furnace), and for the production of plant steam. The plant light ends (C1, C2, etc.), which are normally utilized as fuel gas streams are the primary feeds to the SMR Unit along with the tail gas purge from a gasification complex within the facility.

Abstract: A method for oxidizing carbon monoxide by a water-gas shift (WGS) reaction and a method for reducing carbon dioxide by a reverse water-gas shift (RWGS) reaction, both using a catalyst of the formula xMZLn2O2SOy, in which M, Ln, x, and y are as defined herein. Also disclosed are novel compositions for use as catalysts for both the WGS and RWGS reactions.

Abstract: A composition that comprises a support material having incorporated therein a metal component and impregnated with both hydrocarbon oil and a polar additive. The composition that is impregnated with both hydrocarbon oil and polar additive is useful in the hydrotreating of hydrocarbon feedstocks, and it is especially useful in applications involving delayed feed introduction whereby the composition is first treated with hot hydrogen, and, optionally, with a sulfur compound, prior to contacting it with a hydrocarbon feedstock under hydrodesulfurization process conditions.

Abstract: A process of treating hydrogen gas liberated from the acid or alkaline dissolution of a metal is provided. The process comprises a step of passing the liberated hydrogen gas through a reactor containing an oxidising agent for oxidation of the hydrogen gas into water, followed by a step of regenerating the oxidising agent. Also provided is an apparatus for carrying out the process, the apparatus comprising a reactor containing the oxidising agent, wherein the reactor is at least partially immersed in an alumina bath.

Abstract: A feed gas comprising CO2, H2S and H2 is treated to produce an H2-enriched product and an H2S-lean, CO2 product. The feed gas is separated to provide the H2-enriched product and a stream of sour gas. The stream of sour gas is divided into two parts, one of which is processed in an H2S removal system to form one or more streams of sweetened gas, and the other of which bypasses the H2S removal system, the stream(s) of sweetened gas and the sour gas bypassing the H2S removal system then being recombined to form the H2S-lean, CO2 product gas. The division of the sour gas between being sent to and bypassing the H2S removal system is adjusted responsive to changes in the H2S content of the sour gas, so as to dampen or cancel the effects of said changes on the H2S content of the H2S-lean, CO2 product gas.

Abstract: Disclosed herein are rod-packing robust microporous metal-organic frameworks having the repeat unit Zn4(OH)2(1,2,4-BTC)2, useful for applications such as selective gas storage, selective gas sorption and/or separation, selective sensing of chemicals, and catalysis.

Abstract: A process for working up an exhaust gas A from a system for producing hydroxylamine or hydroxylammonium salts by catalytic reduction of nitrogen monoxide with hydrogen, wherein the exhaust gas A comprises nitrogen monoxide, hydrogen, dinitrogen monoxide, nitrogen and ammonia, and at least some of the hydrogen present in the exhaust gas A is separated off from the exhaust gas A by means of a gas-tight membrane-electrode assembly which comprises at least one selectively proton-conducting membrane, a retentate side, a permeate side, and, on each side of the membrane, at least one electrode catalyst, wherein, on the retentate side of the membrane, at least some of the hydrogen is oxidized to protons at the anode catalyst and the protons, after crossing the membrane, are, on the permeate side, at the cathode catalyst according to I reduced to hydrogen and/or II reacted with oxygen to form water, wherein the oxygen originates from an oxygen-comprising stream O which is contacted with the permeate side.

Abstract: The apparatus and process for separating hydrogen isotopes is provided using dual columns, each column having an opposite hydrogen isotopic effect such that when a hydrogen isotope mixture feedstock is cycled between the two respective columns, two different hydrogen isotopes are separated from the feedstock.

Abstract: Plate-shaped composite getter materials for the sorption of gases containing two interpenetrating constituents, a reinforcing component of skeletal framework and a reactive matrix, which form a coherent monolithic structure, a method for producing such composites, and their application in vacuum technology or gas purification are described. A synthetic getter composite of the classical type in the form of a thin monolithic plate with two constituents, a reinforcing framework embedded in a reactive matrix, has been developed. Metallic gauze made of high-melting transitional metals or their alloys is used as a reinforcing constituent and a reactive metal or alloy with a high concentration of this metal is used as the reactive matrix.

Abstract: The present invention is a hydrogen combustion catalyst including a catalyst metal supported on a carrier composed of an inorganic oxide, wherein a functional group having at the end thereof at least an alkyl group having three or less carbon atoms is bonded by substitution to each of a certain fraction or the whole of the hydroxyl groups on the surface of the carrier. The functional group bonded to each of a certain fraction or the whole of the hydroxyl groups on the surface of the carrier is preferably an organic silane. The hydrogen combustion catalyst according to the present invention is capable of maintaining the activity thereof even when a hydrogen-containing gas, a treatment object, contains a water content equal to or less than the saturated water vapor content and the reaction temperature is set at or around room temperature, namely, at 0 to 40° C.

Abstract: The invention relates to a device (1) for transporting and/or storing radioactive materials (10), comprising a closed enclosure (8) and a system (12, 16) for securing said closed enclosure, said system comprising catalytic means (12) for recombining hydrogen and oxygen into water, placed in said closed enclosure. According to the invention, the system for securing said closed enclosure further comprises a device (16) for the controlled release of oxygen in said closed enclosure (8).

Abstract: A composition that comprises a support material having incorporated therein a metal component and impregnated with both hydrocarbon oil and a polar additive. The composition that is impregnated with both hydrocarbon oil and polar additive is useful in the hydrotreating of hydrocarbon feedstocks, and it is especially useful in applications involving delayed feed introduction whereby the composition is first treated with hot hydrogen, and, optionally, with a sulfur compound, prior to contacting it with a hydrocarbon feedstock under hydrodesulfurization process conditions.

Abstract: A method of separation of hydrogen from gas mixtures consisting in that a gas mixture (3) with any hydrogen content is introduced into a closed space (4), in which a polymer foam (1) containing non-communicating pores (2) is placed. Due to the fact that the hydrogen partial pressure in pores (2) of the polymer foam (1) is lower, hydrogen penetrates into the pores. Hence, the gas mixture (3) leaving the closed space (4) is deficient in the hydrogen. The inlet of the gas mixture (3) into the closed space (4) can be interrupted at the time when the leaving mixture has the same composition as the introduced gas mixture (3) or earlier. Then the pressure in the closed space (4) is decreased and, due to the leveling of its partial pressure, hydrogen is released from the polymer foam (1) and can be received for further use. Its concentration is higher than in the starting gas mixture (3).

Abstract: Some or all of the needs above can be addressed by embodiments of the invention. According to embodiments of the invention, systems and methods for facilitating hydrogen storage using naturally occurring nanostructure assemblies can be implemented. In one embodiment, a method for storing hydrogen can be provided. The method can include providing diatoms comprising diatomaceous earth or diatoms from a predefined culture. In addition, the method can include heating the diatoms in a sealed environment in the presence of at least one of titanium, a transition metal, or a noble metal to provide a porous hydrogen storage medium. Furthermore, the method can include exposing the porous hydrogen storage medium to hydrogen. In addition, the method can include storing at least a portion of the hydrogen in the porous hydrogen storage medium.

Abstract: A feed gas comprising CO2, H2S and H2 is treated to produce an H2-enriched product and a CO2 product. The feed gas is separated by pressure swing adsorption to provide a stream of the H2-enriched product, and two streams of sour gas depleted in H2 and enriched in H2S and CO2 relative to the feed gas. One of the streams of sour gas is processed in an H2S to elemental sulfur conversion system, in which H2S in the sour gas is converted to elemental sulfur order to obtain a stream of sweetened gas, from which the CO2 product is formed. The other of said streams of sour gas is processed in an oxidation system, in which H2S in the sour gas is oxidized to SOx(SO2 and SO3) which is introduced into the H2S to elemental sulfur conversion system.

Abstract: Example embodiments relate to methods of controlling hydrogen concentrations in an offgas system of a nuclear reactor by passive air injection. A method according to a non-limiting embodiment may include passively injecting ambient air through the hydrogen water chemistry system into an existing offgas line of the offgas system. The offgas line is configured to transport non-condensable gases, including hydrogen, from a condenser to a recombiner. As a result of the passive air injection, the combined flow of hydrogen and oxygen react in the recombiner to form water vapor, thereby reducing the hydrogen concentration of the offgas exiting the recombiner.

Abstract: Getter alloys particularly suitable for hydrogen sorption are described. The getter alloys include a first element consisting of yttrium or a yttrium equivalent mixture, the first element forming at least 30% by atoms of the alloy. A method for removing hydrogen from devices which are sensitive to the presence thereof and hydrogen-sensitive devices which contain the described getter alloys are also described.

Abstract: The invention relates to a composition capable of trapping hydrogen comprising: (a) at least one mineral compound of formula (I) below: MX(OH)??(I) in which: M represents a divalent transition element; O represents an oxygen atom; X represents an atom chosen from S, Se, Te, Po; and H represents a hydrogen atom; and (b) at least one nitrate salt of formula (II) below: ZNO3??(II) in which Z is a monovalent cation. Use of these compositions either in pulverulent form for trapping gaseous hydrogen by direct interaction, or in the form of an adjuvant in a containment material for, for example, trapping hydrogen released by radiolysis in radioactive waste packages.

Abstract: The present invention relates to the selective separation of hydrogen (“H2”) hydrocarbons in streams containing both hydrogen and hydrocarbons (e.g. methane, ethylene, ethane, propylene, propane, etc.) utilizing a zeolitic imidazolate framework (“ZIF”) material. Preferably, the stream to be separated is fed to the present process in a substantially gaseous phase. In preferred embodiments, the current invention is utilized in either a pressure swing adsorption process, a temperature swing adsorption process, or a membrane separations process to separate hydrogen from hydrocarbons present in hydrogen production streams or petrochemical/petroleum refining product streams and intermediate streams.

Abstract: A reformer that produces reformed gas from a hydrocarbon material includes a reforming chamber having an inner cylinder and an outer cylinder; a reforming catalyst filled in the reforming chamber; a burner that heats the reforming catalyst and fuel of reformed gas; a combustion gas outer flow channel through which combustion gas of the burner flows along an outer side surface of the reforming chamber; a combustion gas inner flow channel through which the combustion gas of the burner flows along an inner side surface of the reforming chamber; and a plurality of return pipes as a reformed gas flow channel.

Abstract: The present invention relates to nanocomposite materials comprising: graphite-based material dispersed among transition metal-organic framework (MOF) units, wherein the graphite-based material is chemically linked to MOF units; wherein the graphite-based material is present in the range of about 5 wt. % to about 60 wt. % of the composite material.

Abstract: The disclosure provides methods and systems for sequestering and/or reducing sulfur oxides, nitrogen oxides and/or carbon dioxide present in industrial effluent fluid streams. A solid particulate material comprising a slag component, a binder component (distinct from the slag component), and optionally water is formed and then contacted with the effluent fluid stream to reduce at least one of the sulfur oxides, nitrogen oxides, and/or carbon dioxide. The contacting of the effluent stream may occur in a packed bed reactor with the solid dry particulate material. Methods of reducing pollutants from exhaust generated by combustion sources, lime and/or cement kilns, iron and/or steel furnaces, and the like are provided.

Abstract: The present invention provides a membrane, comprising in said order a first electronically conducting layer, an ionically conducting layer, and a second electronically conducting layer, characterized in that the first and second electronically conducting layers are internally short circuited. The present invention further provides a method of producing the above membrane, comprising the steps of: providing a ionically conducting layer; applying at least one layer of electronically conducting material on each side of said ionically conducting layer; sintering the multilayer structure; and impregnating the electronically conducting layers with a catalyst material or catalyst precursor material.

Abstract: A process for cracking hydrocarbons at atmospheric pressure includes the following steps: providing a catalyst, passing a gaseous hydrocarbon over the catalyst and exposing the catalyst to microwave energy. The hydrocarbons are broken down into lower Carbon number molecules.

Abstract: A reaction device can raise heat use efficiency. The reaction device includes a carbon monoxide remover removing carbon monoxide, and a vaporizer provided inside the carbon monoxide remover to vaporize fuel.

Abstract: Example embodiments relate to methods of controlling hydrogen concentrations in an offgas system of a nuclear reactor by passive air injection. A method according to a non-limiting embodiment may include passively injecting ambient air through the hydrogen water chemistry system into an existing offgas line of the offgas system. The offgas line is configured to transport non-condensable gases, including hydrogen, from a condenser to a recombiner. As a result of the passive air injection, the combined flow of hydrogen and oxygen react in the recombiner to form water vapor, thereby reducing the hydrogen concentration of the offgas exiting the recombiner.

Abstract: The inventive stage system for producing hydrogen consists of at least two upstream/downstream stages, respectively, each of which comprises, optionally, a catalytic reactor (C1 to C5) followed by a separator comprising a space (E1 to E4) for circulation of a gaseous mixture contacting at least one oxygen extracting membrane and a hydrogen collecting space, wherein the reactor (C1) of the upstream stage is connected to a reaction gaseous mixture source, the circulation stage (E1) of the upstream stage separator is connected to the reactor (C2) of the downstream stage and the spaces for extracting/collecting oxygen from two separators are connected to a hydrogen collecting circuit (TC, 8) which is common for two stages.

Abstract: Hydrogen (H2) gas and crude carbon dioxide (CO2) gas are separated from a gaseous mixture thereof. Combustible gas(es) in the crude CO2 gas are combusted to produce heat, at least a portion of which is recovered by indirect heat exchange with at least a portion of the separated H2 gas or a gas derived therefrom. The invention may be integrated with coal-fired power stations to reduce or eliminate emission of harmful components into the atmosphere.

Abstract: A method is described for treating a gas stream containing either fuel only or both fuel and oxidant gases, such as hydrogen, nitrous oxide or a hydrocarbon gas. The gas stream is conveyed through a vacuum pumping arrangement comprising a plurality of pumping stages. Either immediately before or immediately after the final pumping stage, the steps of adding a gaseous oxidant to the gas stream and oxidising the fuel gas are performed. By treating the gas stream in this manner, the risk of uncontrolled combustion of the fuel gas can be minimised.

Abstract: By means of a method and a system for heating and partial oxidation of not separately pre-heated, pre-reformed steam/natural gas mixture for an NH3 synthesis gas, whereby energy is supplied to the gas stream (raw synthesis gas), in the direction of flow, after a primary reformer, a solution is to be created, with which soot formation is to be prevented as much as possible, whereby the possibility of the addition of variable amounts, for example of N2 and O2 or mixtures thereof, is also supposed to be possible. This is achieved, according to the method, in that the energy is supplied directly after the primary reformer, by way of at least one pore burner positioned in the gas discharge line of the primary reformer.

Abstract: The present invention relates to zeolitic compositions of at least one A, X, Y zeolite and/or chabazite and at least one clinoptilolite type of zeolite. These zeolitic compositions can be used in adsorption methods for removing H2O and/or CO2 and/or H2S present in gas or liquid mixtures, particularly for purifying natural gas, acid gases, alcohols and mercaptans.

Abstract: A gas separation membrane and a method of manufacturing such gas separation membrane that comprises a porous substrate treated with a layer of metal-coated inorganic oxide particles and with the layer of such metal-coated inorganic oxide particles being coated with an overlayer of a gas-selective material.

Abstract: A process for separating hydrogen from a gas flow having an oxygen constituent and including predominantly hydrogen, nitrogen, oxygen, carbon dioxide, carbon monoxide, methane and/or other hydrocarbons, as well as a device for conducting the process, is disclosed. The gas flow undergoes a process to thermally convert oxygen prior to the pressure swing adsorption process.

Abstract: The present invention provides a method for binding gaseous molecules, the method comprising contacting gases comprising the gaseous molecules with trivalent metal complexes. Typically, the gaseous molecules comprise polar molecules of greenhouse gases, especially the oxides of carbon, nitrogen and sulphur. Preferably, the trivalent metal complexes comprise complexes of actinide metals, most preferably uranium. The method is particularly useful in the removal of so-called greenhouse gases from the atmosphere, and is therefore of potentially very great value environmentally. The invention also provides trivalent metal complexes comprising sandwich complexes of trivalent metals selected from transition metals and actinide metals, the complexes comprising two ligands selected from pentalenyl, indenyl, cyclopentadienyl and cyclooctatetraene ligands. The invention further provides a method for the preparation of the trivalent metal complexes.

Abstract: A hydrogen generation system is disclosed that includes a fuel reforming reactor generating a hydrogen-rich reformate gas at a temperature greater than 150 C, a pressure swing adsorption (PSA) hydrogen purification unit that separates the reformate gas into a relatively pure hydrogen stream and an off-gas stream, and a catalytic reactor down stream of the PSA unit that converts carbon monoxide (CO) and hydrogen (H2) contained in the relatively pure hydrogen stream into methane (CH4) and water vapor (H2O). The method of purification involves generating a hydrogen-rich reformate gas at a temperature greater than 150 C in a fuel reforming reactor, separating the reformate gas into a relatively pure hydrogen stream and an off-gas stream in a pressure swing adsorption (PSA) hydrogen purification unit, and converting carbon monoxide (CO) and hydrogen (H2) contained in the relatively pure hydrogen stream into methane (CH4) and water vapor (H2O) in a catalytic reactor down stream of the PSA unit.

Abstract: This gas purifying process removes trace constituents from a mixed gas that includes a rare gas and nitrogen as main components, and at least one from among hydrogen, nitrogen and hydrogen reaction products, and water vapor as the trace constituent. This process sequentially carries out an adsorbing step for removing water vapor and nitrogen and hydrogen reaction products; a hydrogen oxidation step for converting the hydrogen into water vapor by means of a hydrogen oxidation catalytic reaction in the presence of oxygen; and a drying step for removing water vapor generated in the hydrogen oxidation step. When nitrogen oxides are included as a trace constituent, then a denitration step is carried out prior to the adsorbing step, to convert nitrogen oxides into nitrogen and water vapor by means of a catalytic denitration reaction in the presence of a reducing substance.