Process using plate arrangement for exothermic reactions

A process for contacting reactants with a catalyst in a reaction zone while indirectly heating the reactants and cooling the reaction zone by indirect heat exchange with the reaction zone, the process comprising:

• a) passing a reactant-containing stream through a plurality of narrow heated channels defined by at least a portion of principally spaced apart plates to heat the reactant-containing stream;
• b) passing a heated reactant stream to a plurality of narrow reaction channels defined by another portion of the spaced apart plates and containing a catalyst material therein;
• c) indirectly heating the reactant-containing stream in the heated channels by indirect heat exchange across the portion of the spaced apart plates that defines the reaction channels to simultaneously cool the reaction channels;
• d) communicating common ends of the narrow heated channels with the reaction channels across an open chamber at one end of the reaction and heated channels to pass at least a portion of the reactant-containing stream from the heated channels to the reaction channels as at least a portion of the heated reaction stream;
• e) mixing an additional reactant with the reactant-containing stream in the chamber;
• and,
• f) collecting a primary effluent stream from the reaction channels.