Method for preparing catalyst in preparation of acrylic acid by oxidizing acrolein

Abstract

The invention relates to a method for preparing a catalyst in preparation of acrylic acid by oxidizing acrolein. The general formula of the catalyst is Mo12VaCubWcXdYeOf / Z; and the catalyst is molded by baking for 1 to 24h at the temperature of between 350 and 410 DEG C, and is treated for 3 to 60 hours in mixed gas of air and vapor in any proportion at the temperature of between 260 and 390 DEG C before reaction. The method has the characteristics that: after the catalyst is treated before the reaction, the activity is greatly improved and the catalyst can achieve a steady state at an initial stage of the reaction, so that the danger that the interlocking is caused or the catalyst is damaged caused by hot spot jump or temperature runaway due to overhigh temperature in the running process is avoided; and the catalyst is favorable for being used on industrial devices and is applicable to exhaust gas cycling and non-exhaust gas cycling processes.

Description

technical field [0001] The invention relates to a preparation method and application of a catalyst for acrolein oxidation to acrylic acid. Background technique [0002] Mo-V system composite oxide is an effective catalyst for the oxidation of acrolein to acrylic acid. In industrial production, in order to increase the output, the raw material containing acrolein with a higher concentration or the method of increasing the space velocity is adopted, and the inherent strong exothermic nature of the reaction causes a large amount of heat generated during the reaction to form a high temperature in the catalyst bed. Partially, it is easy to cause excessive oxidation to reduce the selectivity and yield of the catalyst, and also cause accelerated deactivation or even damage of the catalyst. The bigger problem it brings is that the reaction is out of control due to excessive bed temperature or overheating, which makes the driving process extremely difficult, and even faces chain pro...

AI Technical Summary

Problems solved by technology

These methods have played a certain role in suppressing the temperature of the hot spot, but generally the amount of catalyst active material at the feed gas inlet of the reactor is less than the amount of catalyst active material at the outlet, resulting in that the catalyst at the inlet loses more than the catalyst at the outlet. Live fast, which affects the stability of the catalyst for long-term operation under high-yield conditions

Adding toxic components to reduce the activity of the catalyst, although it can achieve the effect of suppressing the temperature of the superheated part, makes the conversion rate of acrolein not high in the early stage, resulting in a decrease in the yield, and the toxic components are adsorbed on the active sites of the catalyst Later, after a longer oxidation reaction, it will affect the stability of the catalyst