US 9,266,081 B2 · Device and process for catalytic gas phase reactions and use thereof

Abstract

Improved reactors for catalytic, exothermic gas phase reactions with, as seen in the flow direction of a feed gas, which contains at least one oxidant and at least one component to be oxidized, an entry zone (1), a reaction zone (2) comprising at least one catalyst (4) and an exit zone (3) for the product gas are described. The reactors, at least in the area of the entry zone (1), have means, for example insulating jackets (6) and/or devices for the transport of cooling agents, which decrease the transport of heat produced in the reaction zone (2) into the entry zone (1) and thus decrease the risks of pre-ignition of the feed gas mixture employed or of the course of undesired side reactions in the entry zone (1) and/or wherein the inner walls of the reactor, at least in the area of the entry zone (1), are elaborated from inert material. The feed gas enters into the entry zone (1) as a homogeneous gas mixture with respect to its substance composition via one or more feed lines (30). The reactors can especially be employed for ammonia oxidation, for example in nitric acid plants, in which transition metal catalysts preferably elaborated in honeycomb form with smaller cross sections than the customarily employed platinum gauzes are used.

Claims25

Dependent claims

A reactor for catalytic, exothermic gas phase reactions by conversion of a feed gas to a product gas comprising a housing having formed therein:

an entry zone, devoid of fittings designed to generate turbulence for intermixing of gas passing therethrough,
a reaction zone comprising at least one catalyst, and
an exit zone for the product gas,
wherein means comprising at least one feed line are provided for supplying a gas mixture to the entry zone as feed gas which is homogeneous with respect to its chemical composition, said gas mixture containing at least one oxidant and at least one component to be oxidized,
wherein, at least in the area of the entry zone, means are provided for forestalling undesired reactions in the entry zone, said means for forestalling undesired reactions comprising
means which decrease the transport of reaction heat generated in the reaction zone into the entry zone and
inert material lining at least a portion of the inner walls of the reactor either in the area of the entry zone or in the area of the reaction zone,
wherein the inert material is selected to be a material which does not promote any undesired side reactions at the temperatures prevailing in the feed gas in the entry zone and at the temperatures on the surfaces of the reactor inner wall, and
wherein the inert material is selected from the group consisting of ceramics, quartz glass, chamotte, enamel, and passivated metals.

6 more elements

A process for carrying out catalytic, exothermic gas phase oxidations of ammonia in air comprising the steps of:

i) introducing a mixture of ammonia in air which is homogeneous with respect to its chemical composition as a feed gas through at least one feed line into the entry zone of a reactor,
ii) controlling the conditions under which the feed gas from the entry zone is supplied to the reaction zone comprising at least one catalyst such that the feed gas reacts in an exothermic reaction in the reaction zone to produce a product gas stream comprising nitric oxide (NO),
iii) leading the product gas through an exit zone from the reactor, and
iv) providing means comprising inert material for forestalling premature reaction in the entry zone of the reactor by decreasing the transport of reaction heat formed in the reaction zone into the entry zone and forming the inner walls of the reactor from inert material over a region extending over at least a portion of the entry zone or a portion of the reaction zone,
wherein the inert material is selected to be a material which does not promote any undesired side reactions at the temperatures prevailing in the feed gas in the entry zone and at the temperatures on the surfaces of the reactor inner wall, and
wherein the inert material is selected from the group consisting of ceramics, quartz glass, chamotte, enamel, and passivated metals.

3 more elements

Dependencies are inferred from the claim text.

Device and process for catalytic gas phase reactions and use thereof

Life of this patent

Device and process for catalytic gas phase reactions and use thereof

Life of this patent

Abstract

Claims25