US Patent 7132555 Rod-shaped inserts in reactor tubes

A process for catalytically reacting a fluid reactant mixture in a multi-tubular reactor system to form a fluid product, whereby the reactant mixture is led through at least one reactor tube containing a fixed bed of solid particulate catalyst and surrounded by a heat-exchange fluid, and whereby an upstream portion of the reactor tube is dedicated to pre-heating the reactant mixture and/or a downstream portion of the reactor tube is dedicated to post-cooling the product, characterized in that the upstream portion and/or downstream portion of the reactor tube contains a heat-exchanging essentially rod-shaped insert, the insert having a length of from 1 to 20%, preferably 1 to 5%, of the total length of the reactor tube.