Isothermal reactor

A method of reducing temperature variation across one or more reaction zones in a reactor for thermochemical reactions,

• wherein said reactor comprises:
• a reactor shell having an inlet for receiving reactants into the reactor and an outlet for the removal of products from the reactor;
• a plurality of reaction zones comprising a solid catalyst in which at least a portion of the reactants undergo a thermochemical reaction;
• a plurality of heat exchange zones located within the reactor shell comprising a heat exchange medium;
• and
• a plurality of tubes for housing or the heat exchange medium, wherein heat is exchanged between the reaction zones and the heat exchange medium through walls of the tubes,
• the method comprising:
• introducing one or more hollow inserts at least partially extending through one or more reaction zones thereby to displace solid catalyst in the reaction zone and reduce temperature variation across the reaction zone, each hollow insert comprising an inlet and an outlet, the hollow inserts configured to:
• form a flow path to divert a portion of the reactants or reaction mixture from the reactor inlet or from one reaction zone to a different reaction zone.