A plant and process for producing a hydrogen rich gas are provided, said process comprising the steps of: reforming a hydrocarbon feed in a reforming step thereby obtaining a synthesis gas comprising CH.sub.4, CO, CO.sub.2, H.sub.2 and H.sub.2O; shifting said synthesis gas in a shift configuration including a high temperature shift step; removal of CO.sub.2 upstream hydrogen purification unit, such as a pressure swing adsorption unit (PSA), and recycling off-gas from hydrogen purification unit and mix it with natural gas upstream prereformer feed preheater, prereformer, reformer feed preheater or ATR or shift as feed for the process.

A process for recovering hydrogen from dehydrogenation reactor effluent is disclosed. A feed stream comprising hydrocarbons and hydrogen to a dehydrogenation reactor maintained at dehydrogenation conditions to provide a dehydrogenation reactor effluent. The dehydrogenation reactor effluent is passed to a cold box separation unit to provide a liquid hydrocarbon product stream and a recycle hydrogen stream. A return portion of the recycle hydrogen stream is passed to the reactor effluent compressor. The subject matter disclosed improved process and apparatus which enables the paraffin dehydrogenation reactor to run at reduced H.sub.2/HC ratio without requiring an investment in a resized compressor or resized turboexpanders or separators in the cold box.

Improved processes and systems are disclosed for producing renewable hydrogen suitable for reducing metal ores, as well as for producing activated carbon. Some variations provide a process comprising: pyrolyzing biomass to generate a biogenic reagent comprising carbon and a pyrolysis off-gas; converting the pyrolysis off-gas to additional reducing gas and/or heat; reacting at least some of the biogenic reagent with a reactant to generate a reducing gas; and chemically reducing a metal oxide in the presence of the reducing gas. Some variations provide a process for producing renewable hydrogen by biomass pyrolysis to generate a biogenic reagent, conversion of the biogenic reagent to a reducing gas, and separation and recovery of hydrogen from the reducing gas. A reducing-gas composition for reducing a metal oxide is provided, comprising renewable hydrogen according to a hydrogen-isotope analysis. Reacted biogenic reagent may also be recovered as an activated carbon product. Many variations are disclosed.

A process for producing a gas stream comprising carbon monoxide comprising the steps of (a) feeding a gas mixture comprising carbon dioxide and hydrogen to a burner and combusting it with a sub-stoichiometric amount of an oxygen gas stream to form a combusted gas mixture comprising carbon monoxide, carbon dioxide, hydrogen and steam, (b) passing the combusted gas mixture through a bed of reverse water-gas shift catalyst to form a crude product gas mixture containing carbon monoxide, steam, hydrogen and carbon dioxide, (c) cooling the crude product gas mixture to below the dew point and recovering a condensate to form a dewatered product gas, (d) removing carbon dioxide from the dewatered product gas in a carbon dioxide removal unit to form the gas stream comprising carbon monoxide, and (e) combining carbon dioxide recovered by the carbon dioxide removal unit with the gas mixture comprising hydrogen and carbon dioxide.

In order to separate diborane from a gas mixture containing diborane and hydrogen, the gas mixture is normally cooled in a storage tank using liquid nitrogen, wherein the diborane freezes out. In order to enable an extensively continuous separation of the diborane from the gas mixture, according to the invention, the gas mixture is brought into thermal contact with a liquefied gas in a heat exchanger, which liquefied gas is held at a pressure such that the diborane is liquefied by the thermal contact with the coolant, and the liquefied diborane is then discharged from the first heat exchanger and supplied to a storage tank. In a downstream, second heat exchanger, the diborane remaining in the gas mixture can then be caused to freeze out.

It has been discovered that mixed-alcohol production can utilize the waste tail gas stream from the pressure-swing adsorption section of an industrial hydrogen plant. Some variations provide a process for producing mixed alcohols, comprising: obtaining a tail-gas stream from a methane-to-syngas unit (e.g., a steam methane reforming reactor); compressing the tail-gas stream; separating the tail-gas stream into at least a syngas stream, a CO.sub.2-rich stream, and a CH.sub.4-rich stream; introducing the syngas stream into a mixed-alcohol reactor operated at effective alcohol synthesis conditions in the presence of an alcohol-synthesis catalyst, thereby generated mixed alcohols; and purifying the mixed alcohols to generate a mixed-alcohol product. Other variations provide a process for producing clean syngas, comprising: obtaining a tail-gas stream from a methane-to-syngas unit; compressing the tail-gas stream; separating the tail-gas stream into at least a syngas stream, a CO.sub.2-rich stream, and a CH.sub.4-rich stream; and recovering a clean syngas product.

A hydrogen feed stream comprising oxygen and one or more impurities selected from the group consisting of nitrogen, argon, methane, carbon monoxide, carbon dioxide, and water, is purified by first removing oxygen using a copper oxide and/or manganese oxide getter, then using a cryogenic temperature swing adsorption (CTSA) process with high overall recovery of hydrogen. The oxygen getter prevents an explosive mixture of hydrogen and oxygen from occurring in the CTSA during regeneration.

A hydrogen feed stream comprising one or more impurities selected from the group consisting of nitrogen, argon, methane, carbon monoxide, carbon dioxide, oxygen, and water, is contacted with liquid hydrogen in a cryogenic wash column (CWC) process that produces pure hydrogen with high overall recovery. The waste liquid stream leaving the CWC may be used to improve the performance of upstream hydrogen processing steps.

A hydrogen feed stream comprising oxygen and one or more impurities selected from the group consisting of nitrogen, argon, methane, carbon monoxide, carbon dioxide, and water, is purified using a cryogenic temperature swing adsorption (CTSA) process with high overall recovery of hydrogen. The CTSA is regenerated using an inert gas to prevent an explosive mixture of hydrogen and oxygen from occurring.

A process for steam reforming a hydrocarbon feedstock containing one or more nitrogen compounds, including passing a mixture of the hydrocarbon feedstock and steam through a catalyst bed of one or more nickel steam reforming catalysts disposed within a plurality of externally heated tubes in a tubular steam reformer, each tube having an inlet to which the mixture of hydrocarbon and steam is fed, an outlet from which a reformed gas containing hydrogen, carbon monoxide, carbon dioxide, steam, ammonia and methane is recovered. The steam reforming catalyst at least at the outlet of the tubes comprises nickel dispersed over a porous metal oxide surface present as a coating on a non-porous metal or ceramic structure. The nickel content of the metal oxide coating is in the range of 5 to 50% by weight and the thickness of the coating is in the range of 5 to 150 micrometres.