FIXED CATALYST BED REACTOR

PURPOSE:To suppress a temperature rise at the inlets of catalyst beds by arranging inner tubes at the centers of reaction tubes surrounded by a coolant, by packing a catalyst between the reaction tubes and the inner tubes and by allowing a raw reactant gas to flow through the inner tubes concurrently with a reaction gas flowing through the catalyst beds in the reaction tubes. CONSTITUTION:A raw reactant gas is introduced from a piping 1, supplied to more than one branch pipes 3 by way of a gas distributor 2 and led into inner tubes 4 to cool catalyst beds 5. The gas from the inner tubes 4 is introduced into a gas collector 14 and a collected gas tube 15 by way of lower branch pipes 13. The gas out of the collected gas tube 15 is turned back in an upper channel chamber 16, distributed evenly to more than one reaction tubes 6 and led into the catalyst beds 5 to carry out a reaction. The gas flowing through the catalyst beds 5 is cooled by the raw reactant gas etc. flowing concurrently through the inner tubes 4. The reaction gas out of the reaction tubes 6 is collected in a lower channel chamber 17 and flows out of the reactor through a piping 18.