Process and plant for producing pure hydrogen

A process for producing pure hydrogen from an input gas containing hydrogen and hydrocarbons, the process comprising the following steps of:

• a. providing an input gas stream containing hydrogen and hydrocarbons;
• b. supplying the input gas stream containing hydrogen and hydrocarbons to a first hydrogen enrichment stage and separating a first input gas stream in the first hydrogen enrichment stage into a hydrogen-enriched substream and a hydrogen-depleted substream;
• c. providing a reforming feed stream containing hydrocarbons, which is supplied to a steam reforming stage, wherein the steam reforming stage comprises a multiplicity of catalyst-filled reformer tubes which are heated using burners;
• d. at least partially converting the reforming feed stream in the steam reforming stage under steam reforming conditions to afford a reforming product stream containing hydrogen, carbon oxides and unconverted hydrocarbons;
• e. discharging the reforming product stream from the steam reforming stage, performing further treatment steps with the reforming product stream and supplying the treated reforming product stream to a second hydrogen enrichment stage operating according to the principle of pressure swing adsorption;
• f. discharging a pure hydrogen product stream from the second hydrogen enrichment stage;
• g. supplying at least a portion of the hydrogen-enriched substream to the second hydrogen enrichment stage or introduced into the pure hydrogen product stream;
• and
• h. supplying at least a portion of the hydrogen-depleted substream to the steam reforming stage as the reforming feed stream or introduced into the reforming feed stream and/or supplied to the burners as a fuel gas stream,
• wherein the steam reforming stage comprises a plurality of partial reforming stages, wherein the first partial reforming stage in the flow direction is configured as a pre-reforming.

A process for producing pure hydrogen from an input gas containing hydrogen and hydrocarbons, the process comprising the following steps of:

• a. providing an input gas stream containing hydrogen and hydrocarbons;
• b. supplying the input gas stream containing hydrogen and hydrocarbons to a first hydrogen enrichment stage and separating a first input gas stream in the first hydrogen enrichment stage into a hydrogen-enriched substream and a hydrogen-depleted substream;
• c. providing a reforming feed stream containing hydrocarbons, which is supplied to a steam reforming stage, wherein the steam reforming stage comprises a multiplicity of catalyst-filled reformer tubes which are heated using burners;
• d. at least partially converting the reforming feed stream in the steam reforming stage under steam reforming conditions to afford a reforming product stream containing hydrogen, carbon oxides and unconverted hydrocarbons;
• e. discharging the reforming product stream from the steam reforming stage, performing further treatment steps with the reforming product stream and supplying the treated reforming product stream to a second hydrogen enrichment stage operating according to the principle of pressure swing adsorption;
• f. discharging a pure hydrogen product stream from the second hydrogen enrichment stage;
• g. supplying at least a portion of the hydrogen-enriched substream to the second hydrogen enrichment stage or introduced into the pure hydrogen product stream;
• and
• h. supplying at least a portion of the hydrogen-depleted substream to the steam reforming stage as the reforming feed stream or introduced into the reforming feed stream and/or supplied to the burners as a fuel gas stream,
• wherein the reforming feed stream is supplied to a hydrodesulfurization step (HDS), wherein the reforming feed stream is mixed with a hydrogenating agent and under hydrodesulfurization conditions is at least partially freed of sulfur, wherein at least a portion of the hydrogen-enriched substream is used as the hydrogenating agent.