Furnace and steam reforming process

A steam reforming furnace for steam reforming of a hydrocarbon feedstock by reaction under steam reforming conditions with steam in the presence of a steam reforming catalyst to produce a reformed gas mixture comprising carbon oxides and hydrogen, which comprises:

• (a) a furnace chamber;
• (b) a plurality of substantially vertical reformer tubes in the furnace chamber, each reformer tube having a feed inlet at its lower end in communication with a reaction mixture feed manifold, an outlet at its upper end in communication with a reformed gas outlet header, and a catalyst containment zone disposed intermediate its upper and lower ends and containing a charge of a particulate steam reforming catalyst which is insufficient to fill completely the catalyst containment zone;
• (c) burner means in the furnace chamber for externally heating the plurality of reformer tubes so as to maintain steam reforming conditions in each of the plurality of reformer tubes and convert the hydrocarbon feedstock by reaction with steam to a reformed gas mixture comprising carbon oxides and hydrogen;
• (d) upper retainer means mounted at the upper end of the catalyst containment zone of each of the plurality of reformer tubes, the upper retainer means being permeable to gas but adapted to retain particles of the particulate steam reforming catalyst in the catalyst containment zone;
• (e) follower means movably mounted in the catalyst containment zone beneath the charge of particulate steam reforming catalyst for movement upwardly from a lower end of the containment zone upon upward flow of gas through the catalyst containment zone at a rate beyond a threshold rate;
• (f) means for supplying to the reaction mixture feed manifold a reactant mixture comprising the hydrocarbon feedstock and steam at a rate sufficient to cause the reactant mixture to flow upwardly through each reformer tube at a flow rate which is sufficient to cause the particulate steam reforming catalyst in each reformer tube to rise up towards the upper end thereof and form a cushion of particulate steam reforming catalyst particles against the underside of the upper retainer means in the respective reformer tube and which is in excess of the threshold rate so as to cause the follower means in the respective reformer tube to move upwardly until it abuts against the underside of the cushion of particulate steam reforming catalyst in the respective reformer tube;
• and
• (g) means for recovering resulting reformed gas mixture from the reformed gas outlet header.