Corrosion-protected reformer tube with internal heat exchange

A reformer tube for converting a hydrocarbon-containing feed into a synthesis gas product comprising carbon oxides and hydrogen under steam reforming conditions, the reformer tube comprising:

• (a) an outer, pressurized shell tube, wherein the shell tube is divided into a reaction chamber and an exit chamber by means of a separating tray and wherein the reaction chamber is externally heatable;
• (b) a dumped bed of a steam-reforming-active solid catalyst arranged in the reaction chamber;
• (c) an entry for the input gas stream comprising the input material arranged in the region of the reaction chamber, wherein the entry for the input gas stream is in fluid connection with the dumped catalyst bed;
• (d) at least one heat exchanger tube arranged inside the reaction chamber and inside the dumped catalyst bed whose entry end is in fluid connection with the catalyst bed and whose exit end is in fluid connection with the exit chamber, wherein the input gas stream after entry into the reaction chamber initially flows through the catalyst bed and subsequently flows through the heat exchanger tube in countercurrent and is thus continually cooled and wherein the heat exchanger tube is in a heat exchange relationship with the dumped catalyst bed and the input gas stream flowing therethrough;
• and
• (e) a collection conduit for the synthesis gas product which is in fluid connection with the exit chamber,
• wherein the gas-contacted metallic components of the reformer tube are made of a nickel-based alloy and those gas-contacted surfaces having a temperature during operation under defined steam reforming conditions of between 650° C. and 800° C. are equipped with an aluminum diffusion layer.

A process for producing synthesis gas by catalytic steam reforming of hydrocarbon-containing input materials, preferably natural gas, under steam reforming conditions in the presence of a steam-reforming-active, solid catalyst comprising the steps of:

• a. provision of an input gas stream comprising the input material and addition of reforming steam, wherein a steam-carbon ratio S/C arises from the molar ratio of the supplied reforming steam amount and the carbon present in the input material,
• b. catalytic conversion of the input material under steam reforming conditions into a synthesis gas products comprising carbon oxides and hydrogen,
• c. discharging and optional workup of the synthesis gas product,
• wherein the catalytic conversion in step (b) is effected in a reformer tube according to claim 1 at defined steam reforming conditions, in particular in terms of the steam/carbon ratio S/C and the reforming temperature, wherein the gas-contacted metallic components of the reformer tube are made of a nickel-based alloy and those gas-contacted surfaces having a temperature during operation between 650° C. and 800° C. are equipped with an aluminum diffusion layer.