Method for the preparation of synthesis gas

Method for the preparation of synthesis gas comprising the steps of

• (a) preparing a separate hydrogen containing stream and a separate oxygen containing stream by electrolysis of water and/or steam;
• (b) providing a hydrocarbon feed stock;
• (c1) steam reforming a part of the hydrocarbon feed stock from step (b) and/or a second hydrocarbon feedstock in indirect heat transfer relationship with part or all of an autothermal reformed gas leaving step (d) and mixing the heat exchange steam reformed gas stream with the autothermal reformed gas downstream step (d);
• or
• (c2) heat exchange steam reforming a part or all of the hydrocarbon feed stock from step (b) in indirect heat transfer relationship with part or all of an autothermal reformed gas leaving step (d) to a heat exchange steam reformed gas and introducing the heat exchanged steam reformed gas into an autothermal reformer in step (d) to obtain the autothermal reformed gas for use in step (c2);
• (d) providing in an autothermal reformer the autothermal reformed gas for use in step (c1) or step (c2) by autothermal reforming at least a part of the hydrocarbon feed stock from step (b) or at least a part of the heat exchange steam reformed gas from step (c2) with at least a part of the separate oxygen containing stream from step (a);
• (e) introducing at least part of the separate hydrogen containing stream from step (a) into the mixed heat exchange reformed gas and autothermal reformed gas downstream step (c1) or into the autothermal reformed gas downstream step (d) to obtain a synthesis gas comprising hydrogen, carbon monoxide and carbon dioxide;
• and
• (f) withdrawing a synthesis gas.