Patent ID: 9522374
Filing Date: 2016-12-20
CPC Classification: B01J,C07C

Claim Text:
1. An apparatus for preparing maleic anhydride by heterogeneously catalyzed gas-phase oxidation of a feed stream comprising hydrocarbons having at least 4 carbon atoms per molecule, which comprises a reactor having a bundle of reaction tubes into which a solid-state catalyst over which the exothermic reaction of the feed stream with an oxygen-comprising gas stream takes place has been introduced and also one or more pumps and one or more heat exchangers which are located outside the reactor and through which a heat transfer medium formed by a salt melt flows through the intermediate space in the reactor between the reaction tubes and takes up the heat of reaction, with the temperature of the salt melt being in the range from 350 to 480° C., wherein the reaction tubes are made of one of the following heat-resistant alloy steels: material abbreviation 16Mo3, corresponding to the EN material number 1.5415, material abbreviation 13 CrMo4-5, corresponding to the EN material number 1.7335 or material abbreviation 10CrMo9-10 corresponding to the EN material number 1.7380, and wherein in addition to the reaction tubes, all other components of the apparatus which come into contact with the salt melt as heat transfer medium are made of one of the following heat-resistant alloy steels: material abbreviation 16Mo3, corresponding to the EN material number 1.5415, material abbreviation 13 CrMo4-5, corresponding to the EN material number 1.7335 or material abbreviation 10CrMo9-10 corresponding to the EN material number 1.7380.