Technical method for removing propylene glycol in hydrogen peroxide direct oxidation method used for preparing propylene oxide

Abstract

The invention relates to the field of petrochemical engineering, and particularly relates to a technical method for removing propylene glycol in a hydrogen peroxide direct oxidation method used for preparing propylene oxide. The technical method comprises the following steps: mixing dehydration is carried out on a catalyst with hydrogen peroxide and an organic solvent to obtain a mixed liquid; themixed liquid reacts with liquid propylene in a reaction system after dehydration to obtain a reaction working solution; the final reaction working solution enters a crude separation tower, light components such as propylene, epoxypropane and the like are distilled out from the top of the tower, and heavy components such as propylene glycol, a catalyst and the like are distilled out from the bottom of the tower; and further separation is carried out on the light components at the tower top and the heavy components at the tower bottom. According to the final reaction working solution provided by the invention, the heavy components are separated out first by utilizing the crude separation tower, most parts of heavy components containing the catalyst are directly recycled, and small parts ofthe heavy components containing the catalyst are treated by a filter of a water scrubbing tower for recycling the catalyst, so that loss of the catalyst and investment of the filter are reduced. Smallparts of the heavy components are treated by the water scrubbing tower and a propylene glycol recycling tower for recycling propylene glycol, and propylene glycol remaining in the reaction system does not influence the reaction. In addition, the amount of the heavy components is small, so that investment cost and operation cost of the water scrubbing tower and the propylene glycol recycling towerare reduced.

Description

technical field [0001] The invention relates to the field of petrochemical industry, in particular to a process for removing propylene glycol in the production of propylene oxide by direct oxidation of hydrogen peroxide. Background technique [0002] Propylene oxide (PO) is an important basic chemical raw material. The traditional production methods in industry are mainly chlorohydrin method and co-oxidation method. The chlorohydrin method will produce a large amount of calcium chloride and chlorine-containing wastewater, which will cause great environmental pollution; Although the oxidation method has less environmental pollution, it has a large investment and a large amount of co-products, and the co-product market will affect the production of propylene oxide. At present, the production of propylene oxide by oxidizing propylene with hydrogen peroxide has gradually become the main direction of the production method of propylene oxide due to less environmental pollution, le...

AI Technical Summary

Problems solved by technology

[0002] Propylene oxide (PO) is an important basic chemical raw material. The traditional production methods in industry are mainly chlorohydrin method and co-oxidation method. The chlorohydrin method will produce a large amount of calcium chloride and chlorine-containing wastewater, which will cause great environmental pollution; Although the oxidation method has less environmental pollution, it has a large investment and a large amount of co-products. The co-product market will affect the production of propylene oxide

At present, the production of propylene oxide by oxidizing propylene with hydrogen peroxide has gradually become the main direction of the production method of propylene oxide due to less environmental pollution, less co-products, and recyclable catalysts and solvents. However, this method has only completed the laboratory stage now. Research on intermittent production, pilot scale and actual normal continuous production methods and device preparation, especially the separation, purification and reuse of working liquid for subsequent final reactions are still in the development stage

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