Abstract: Apparatus for preparing maleic anhydride by heterogeneously catalyzed gas-phase oxidation of a stream containing hydrocarbons having at least 4 carbon atoms per molecule, which includes a reactor with reaction tubes into which a solid-state catalyst over which the exothermic reaction of the stream with an oxygen-comprising gas stream takes place is introduced and one or more pumps and heat exchangers 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 melt being in the range from 350 to 480° C. The reaction tubes are made of a heat-resistant alloy steel which includes at least 0.5% by weight of chromium or at least 0.25% by weight of molybdenum or both.

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a composite material which consists, on its side in contact with the reaction chamber, of a steel B with specific elemental composition which, on its side facing away from the reaction chamber, either directly or via an intermediate layer of copper, or of nickel, or of copper and nickel, is plated onto a steel A with specific elemental composition, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: A shell which encloses an interior and has at least one first orifice for feeding at least one gas stream into the interior and at least one second orifice for withdrawing a gas stream fed to the interior beforehand via the at least one first orifice from the interior, the surface of the shell, on its side in contact with the interior, being manufactured at least partly, in a layer thickness of at least 1 mm, from a steel which has a specific elemental composition, and in the interior, a process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated is carried out in a reactor which is manufactured from the steel on its side in contact with the reaction gas.

Abstract: 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 a heat-resistant alloy steel which comprises either at least 0.5% by weight of chromium or at least 0.25% by weight of molybdenum or at least 0.5% by weight of chromium and at least 0.25% by weight of molybdenum, is proposed.

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a composite material which consists, on its side in contact with the reaction chamber, of a steel B with specific elemental composition which, on its side facing away from the reaction chamber, either directly or via an intermediate layer of copper, or of nickel, or of copper and nickel, is plated onto a steel A with specific elemental composition, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a composite material which consists, on its side in contact with the reaction chamber, of a steel B with specific elemental composition which, on its side facing away from the reaction chamber, either directly or via an intermediate layer of copper, or of nickel, or of copper and nickel, is plated onto a steel A with specific elemental composition, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a steel with specific elemental composition on its side in contact with the reaction gas, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a steel with specific elemental composition on its side in contact with the reaction gas, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: An apparatus for making polyamides oligomers thereof mixtures thereof, the apparatus comprising a material selected from the group consisting of a) an austenitic steel comprising from 15 to 25% by weight of chromium, from 3 to 35% by weight of nickel and from 0 to 10% by weight of molybdenum, and iron, b) a duplex steel comprising from 20 to 30% by weight of chromium, from 3 to 10% by weight of nickel and from 0 to 5% by weight of molybdenum, and iron, and c) a nickel-based alloy comprising from 12 to 25% by weight of chromium and from 12 to 20% by weight of molybdenum, and nickel