A process for producing a synthesis gas product stream having an adjustable hydrogen-carbon monoxide ratio (H2/CO ratio) and a pure hydrogen stream from an input stream containing hydrocarbons, comprising:
- (a) providing the input stream containing hydrocarbons;
- (b) supplying the input stream containing hydrocarbons to a synthesis gas production plant comprising:
- (b1) a steam reforming stage, or
- (b2) an autothermal reforming stage (ATR), or
- (b3) a partial oxidation stage (PDX), or
- (b4) a combination of at least two of the stages (b1) to (b3);
- (c) at least partial conversion of the input stream containing hydrocarbons in the synthesis gas production plant under synthesis gas production conditions to afford a raw synthesis gas stream containing hydrogen (H2) and carbon monoxide (CO);
- (d) discharging a raw synthesis gas stream from the synthesis gas production plant;
- (e) introducing at least a first proportion of the raw synthesis gas stream into a CO conversion plant comprising at least one CO conversion stage, converting the proportion of the raw synthesis gas stream introduced into the CO conversion plant under CO conversion conditions to afford a verted synthesis gas stream, discharging the converted synthesis gas stream;
- (f) introducing the raw synthesis gas stream and/or the converted synthesis gas stream into a sorption apparatus for removal of acidic gas constituents using a physical or chemical sorption process, discharging a deacidified synthesis gas stream from the sorption apparatus;
- (g) introducing at least a second proportion of the deacidified synthesis gas stream into a first hydrogen enrichment stage containing a hydrogen selective membrane as the separating means, separating the deacidified synthesis gas stream into a hydrogen-enriched permeate stream and into a hydrogen-depleted retentate stream;
- (h) introducing the hydrogen-enriched permeate stream and the proportion of the deacidified synthesis gas stream not passed to the first hydrogen enrichment stage into a second hydrogen enrichment stage operating according to the principle of pressure swing adsorption (PSA);
- (i) discharging a pure hydrogen stream and a carbon monoxide-containing residual gas stream from the second hydrogen enrichment stage;
- and
- (j) discharging the hydrogen-depleted retentate stream from the first hydrogen enrichment stage as a synthesis gas product stream,
- wherein the first proportion and/or the second proportion are chosen such that the molar H2/CO ratio required for the synthesis gas product stream is obtained.