Method of producing unsaturated aldehyde and unsaturated acid in fixed-bed catalytic partial oxidation reactor with enhanced heat control system

Abstract

The present invention provides a process of producing unsaturated aldehydes and unsaturated acids from olefins by fixed-bed catalytic partial oxidation in a shell-and-tube heat exchanger-type reactor. In this process, the reactor comprises a first-step reaction zone of mainly producing the unsaturated aldehydes, a second-step reaction zone of mainly producing the unsaturated acids, or both the two zones. The first-step reaction zone is divided into two or more zones by a partition. Each of the divided shell spaces is filled with a heat transfer medium, and the heat transfer medium in each shell space is maintained at isothermal temperature or a temperature difference of 0-5 DEG C. The temperatures of the heat transfer media in each of the divided shell spaces are set to increase in the moving direction of reactants. In order to facilitate the removal of heat generation at a location where the partition is placed, a reaction inhibition layer is disposed in the first-step reaction zone. Also, in order to protect the catalyst layer from a highly exothermic reaction, the process is performed at a limited temperature difference between the temperature in a hot spot and the temperature of a molten salt. If the improved heat control system according to the present invention is used, the heat stability of the catalyst layer will be secured and the yields of intermediate and final products can be increased.

Description

technical field [0001] The present invention relates to a process for the preparation of unsaturated aldehydes and unsaturated acids from olefins by catalytic vapor phase oxidation, in particular to a process for the preparation of acrolein and acrylic acid from propylene and to a heat exchanger type reactor, in particular a fixed bed shell, for the process - Tubular heat exchanger type reactor. The methods for the preparation of unsaturated aldehydes and unsaturated acids fit typical catalytic vapor-phase oxidations. Background technique [0002] Generally, catalytic vapor phase oxidation is carried out by adding one or more granular catalysts into the reactor tube (catalytic tube), feeding the raw material gas into the reactor through the pipeline, and making the raw material gas and the catalyst contact in the reactor tube . Reaction heat generated during the reaction is removed by heat exchange with a heat transfer medium whose temperature is maintained at a predetermi...

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Problems solved by technology

[0017] As mentioned above, since catalytic vapor phase oxidation is not only carried out at high temperature, but also has an exothermic reaction generated by superheating, it can cause Decreased selectivity and, in the long run, can lead to significant degradation of catalyst performance

In particular, if the temperature of the hot spot is higher than the calcination temperature of the catalyst, the life cycle of the catalyst will be reduced, thereby shortening the replacement time of the entire catalyst layer, resulting in economic loss

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