Reactor for a catalytic conversion reaction comprising within a catalyst housing a perforated catalyst support plate supporting a catalyst bed, the perforated catalyst support plate being supported by a plurality of elongated support elements, and catalyst particles in the catalyst bed being placed outside the elongated support elements, the perforated catalyst support plate being attached to the lower ends of the elongated support elements, the perfo­rated catalyst support plate being divided into a plurality of perforated catalyst support plate segments, at least one perforated catalyst support plate segment being supported by an elongated support element.