Catalyst used for resource utilization of a fixed bed aniline distillation residue and method for preparing said catalyst

Abstract

The present invention relates to a catalyst for fixed bed aniline rectification residue recycling and preparation method thereof. Based on the total weight of the catalyst, the catalyst comprises the following components in percentage by weight: 5-40% of an active component, 2-30% of a first cocatalyst component, 10-30% of a second cocatalyst component and the balance of carrier, wherein the active component is NiO; the first cocatalyst component is one or more of Fe, Mo, Cr or Co oxide; and the second cocatalyst component is one or more of La, Zr, Y or Ce oxide. The catalyst is prepared through co-precipitation. The catalyst shows high activity and stability in the waste liquid treatment process, and can still maintain high rectification residue cracking rate after reaction of 200 hours.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a catalyst and preparation method thereof, and more particularly to a catalyst for fixed bed aniline rectification residue recycling and preparation method thereof.BACKGROUND OF THE INVENTION[0002]Aniline is a colorless, oily liquid with a strong odor and toxicity. It is an important chemical intermediate, and thus is widely used for producing rubber processing aids, dyes, photographic chemicals, pharmaceuticals, pesticides, explosives, polyurethanes and the like. The production methods of aniline comprise phenol ammoniation, iron powder reduction and catalytic hydrogenation of nitrobenzene.[0003]Taking into account the source of raw materials, energy consumption, environmental protection and so on, most manufacturers use catalytic hydrogenation of nitrobenzene. The catalytic hydrogenation may be divided into two processes, i.e., the fixed bed gas phase hydrogenation and fluidized bed gas phase hydrogenation according to t...

AI Technical Summary

Benefits of technology

The present invention is about a catalyst for recycling aniline rectification residue. The catalyst breaks down high molecular weight substances in the residue into smaller molecules, reducing viscosity and facilitating separation. The catalyst is simple and stable. The method involves injecting a mixture of aniline rectification residue, alcohol, and hydrogen into a reactor with the catalyst. The resulting product is analyzed using gas chromatography. The catalyst has good activity and selectivity, and is stable even after long periods of use. Additionally, the synergic effect of the components enhances the stability of the catalyst and alleviates the loss of active constituents. Other components like Y have the function of regulating surface acidity, preventing carbon deposition, and reducing ring opening reactions. Fe helps stabilize the catalyst, while Mo, Cr, Zr, Ce, La, or Co have the functions of reducing carbon deposition and prolonging the life of the catalyst.

Problems solved by technology

The fixed bed gas phase hydrogenation has the advantages of simple process, low maintenance cost, no need for separation of catalyst, low reaction temperature, good product quality and the like, but local overheating (hot spot) is prone to occur due to poor heat transfer of the fixed bed, which leads to side reactions and deactivation of the catalyst.

The fluidized bed reactor has the disadvantages of complicated operation, remarkable catalyst abrasion, and high operation and maintenance costs.

The liquid phase hydrogenation comprises a gas phase reaction and a liquid phase reaction and achieves easy reaction heat removal, and has the advantages of simple equipment and low operation and maintenance costs, but the cost of technology introduction is high.

These factors make aniline rectification residue have high viscosity and poor fluidity, and thus difficult to be reused.

Therefore, most of the aniline rectification residue, as waste liquid, is treated by incineration, but after incineration, it will produce nitrogen oxides and lead to acid rain and pollution environment, and further reduce the output of agriculture and fisheries.

At present, there is no effective method for the utilization of aniline rectification residue.

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