Steam reforming

An apparatus for steam reforming hydrocarbons, comprising a steam reformer having an inlet through which a feed gas mixture may pass and an outlet through which a reformed gas mixture may pass, the steam reformer containing a plurality of externally-heated vertical tubes each tube having:

• a tube inlet for a feed gas mixture comprising hydrocarbon and steam, and
• a tube outlet for a reformed gas mixture,
• wherein:
• the steam reformer inlet is in fluid communication with the tube inlets and the steam reformer outlet is in fluid communication with the tube outlet;
• and
• the plurality of externally-heated vertical tubes each contain a particulate steam reforming catalyst comprising nickel on a refractory oxide adjacent the tube outlet and a structured steam reforming catalyst comprising nickel on a refractory oxide adjacent the tube inlet, and
• the structured steam reforming catalyst is a steam reforming catalyst (a) supported on a metal or ceramic support structure wash-coated with a layer of steam reforming catalyst, said support structure comprising a plurality of passages through which a process fluid may pass in ordered, non-random directions or is a steam reforming catalyst (b) contained within a containing support structure and comprises discrete catalyst containers, cups or cans that include passages through which a process fluid may pass in ordered, non-random directions.