Hydrogen production method and facility
AssigneePraxair Technology, Inc.
InventorsRaymond F. Drnevich, Ramchandra M. Watwe
Life of this patent
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Abstract
A hydrogen production method and facility in which a synthesis gas stream produced by the gasification of a carbonaceous substance is processed within a synthesis gas processing unit in which the carbon monoxide content is reacted with steam to produce additional hydrogen that is removed by a pressure swing adsorption unit. The tail gas from the pressure swing adsorption unit is further reformed with the addition of a hydrocarbon containing stream in a steam methane reforming system, further shifted to produce further additional hydrogen. The further hydrogen is then separated in another pressure swing adsorption unit.
Claims14
A method of producing a hydrogen product from a synthesis gas stream formed by gasifying a carbonaceous feedstock, said method comprising:
- preheating a feed stream comprising the synthesis gas stream and introducing the feed gas stream into a first shift conversion unit to form a first shifted gas stream;
- cooling the first shifted gas stream and introducing the first shifted gas stream into an acid gas removal unit to remove carbon dioxide and sulfur from the first shifted gas stream and thereby form a purified first shifted gas stream;
- separating part of the hydrogen product from the purified first shifted gas stream in a first pressure swing adsorption unit, thereby to also produce a first tail gas stream;
- heating a combined reactant stream in a steam methane reforming system and subjecting the combined reactant stream to steam methane reforming to produce a reformed stream, the combined reactant stream formed by combining steam with at least part of the first tail gas stream and a hydrocarbon containing stream, after having been preheated, the hydrocarbon containing stream and steam being combined at a flow rate such that methanation is at least prevented within the steam methane reformer;
- cooling the reformed stream and introducing the reformed stream into a second shift conversion unit to produce a second shifted gas stream from the reformed stream;
- and
- cooling the second shifted gas stream and separating a remaining part of the hydrogen product therefrom in a second pressure swing adsorption unit, thereby to also produce a second tail gas stream.
A method of producing a hydrogen product within a hydrogen producing facility, said method comprising:
- operating a steam methane reforming system both during an initial time of operation and a subsequent time of operation by:
- heating a combined reactant stream and subjecting the combined reactant stream to steam methane reforming to produce a reformed stream;
- cooling the reformed stream, subjecting the reformed stream to a water-gas shift reaction to produce a gas stream enriched in hydrogen and thereafter, cooling the gas stream and separating hydrogen therefrom through pressure swing adsorption;
- at the initial time of operation of the hydrogen producing facility producing all of the hydrogen product from the steam methane reforming system by forming the combined reactant stream from a hydrocarbon containing stream and steam;
- at the subsequent time of operation of the hydrogen producing facility, retrofitting the hydrogen producing facility with a synthesis gas processing system configured to produce part of the hydrogen product from a feed gas stream comprising synthesis gas produced by gasifying a carbonaceous feed within a gasifier;
- the part of the hydrogen product being produced in the synthesis gas processing system by:
- preheating the feed gas stream and introducing the feed gas stream into a shift conversion unit to form a shifted gas stream;
- cooling the shifted gas stream and introducing the shifted gas stream into an acid gas removal unit to remove carbon dioxide and sulfur from the shifted gas stream and thereby form a purified shifted gas stream;
- and
- separating the part of the hydrogen product from the purified first shifted gas stream in a pressure swine adsorption unit, thereby to also produce a tail gas stream:
- and
- at the subsequent time of operation, the steam methane reforming system producing a remaining part of the hydrogen product by forming the combined reactant stream by combining the steam with at least part of the tail gas stream and the hydrocarbon containing stream, after having been preheated, the hydrocarbon containing stream being combined at a flow rate such that methanation is at least prevented within the steam methane reformer and hydrogen being separated by the pressure swing adsorption being conducted in the steam methane reforming system constituting the remaining part of the hydrogen product.
Dependencies are inferred from the claim text.