RU2394647C1 - Method of regenerating spent palladium-containing catalyst for hydrogenation of plant oil and fat - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to processes of generating catalysts for hydrogenation of plant oil and fat. The invention describes a method of regenerating a spent palladium-containing catalyst for hydrogenating plant oil and fat through treatment with sodium hydroxide solution and washing with a condensate, where the catalyst is pre-washed with steam condensate until there are no traces of fat while simultaneously bubbling with hydrogen. Treatment is carried out with 10% solution of sodium hydroxide while blowing with hydrogen at the same time. Washing is carried out with steam condensate until there are completely no traces of alkali and soap and drying is carried out in a hydrogen stream at 145-150°C for 8-9 hours.

EFFECT: attaining high degree of purification and regeneration of the catalyst.

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Description

The invention relates to processes for the regeneration of catalysts for the hydrogenation of vegetable oils and fats.

A known method of regenerating at least partially spent zeolite catalyst, which comprises treating said spent catalyst with an aromatic hydrocarbon in at least partially a liquid phase at a temperature equal to or higher than the temperature of the alkylation or transalkylation process in which the spent catalyst is obtained, and at a space velocity of the interval from 1 to 20 hours ^-1 . The method is carried out at a temperature of from 150 to 300 ° C, a pressure of from 0.6 to 5.1 MPa (5 to 50 excess bar) and for a period of time from 0.1 to 60 hours (RF Patent No. 2243034, 2000) .

The disadvantages of this method are the high temperature of regeneration, multi-stage and the complexity of the process.

The closest in technical essence is a method of purification of a nickel-ceramic catalyst for the hydrogenation of vegetable oils and fats. The method involves treating the catalyst with an alkali solution and a nonionic detergent with additional floating and dispersing additives: sodium metasilicate, sodium tripolyphosphate and soda ash (AS USSR No. 617066).

In this method, a mixture of alkaline reagents is used, which can be deposited on the surface of the catalyst support and, clogging in the pores, block its active centers. Therefore, in order to completely wash the catalyst from alkaline reagents, a rather long time is required for the washing process in several stages.

The objective of the invention is to simplify the regeneration process while maintaining the efficiency of catalyst recovery.

The problem is solved in that in the method of regeneration of the spent catalyst, by treating it with an alkaline reagent solution and washing with condensate, the catalyst is first washed with steam condensate until there are no traces of fat while hydrogen is sparged, and the treatment is carried out with a 10% sodium hydroxide solution while blowing hydrogen, then washed with steam condensate to a complete absence of traces of alkali and soap and dried in a stream of hydrogen at 145-150 ° C for 8-9 hours.

The loss of catalyst activity occurs mainly due to the blocking of the active sites of the catalyst during the service life when organic substances are deposited in the pores of the catalyst carrier. The catalytic activity of the catalyst can be restored by washing the catalyst from the deposited fat.

Carrying out the processes of washing the catalyst from fat and drying while sparging with hydrogen helps to restore palladium crystallites on the surface of the carrier and increase the activity of the catalyst. In addition, the sparging process provides active mixing of the catalyst and the supplied flushing medium, which contributes to the most complete washing off of traces of grease from the surface of the catalyst.

The study of the catalytic activity of the regenerated samples showed that, at the selected regeneration mode, a rather high degree of purification and restoration of the catalyst activity is achieved.

The method is as follows.

Example 1. After carrying out the hydrogenation process with a decrease in catalyst activity, the supply of raw materials and hydrogen to the column is stopped. The column is filled with hot steam condensate at a temperature of 90 ° C. At the same time, hydrogen is sparged in the column. Washing with steam condensate is carried out until there is no trace of fat in the washing condensate. The fat remaining in the pores of the catalyst is removed by treating the catalyst layer with a 10% NaOH solution and, during the treatment with alkali, hydrogen is bubbled up from the bottom through the catalyst layer. The process is accompanied by the release of foam. The catalyst is washed with a NaOH solution until the evolution of foam ceases, after which the alkali solution is drained from the column. About 15 tons of caustic soda solution are used for washing.

Then the catalyst is washed with steam condensate while sparging with hydrogen until there are no traces of soap and alkali in the wash water (phenolphthalein test).

After washing the catalyst, the condensate is drained and the catalyst is dried in a stream of hydrogen at a temperature of 145 ° C for 8 hours.

Example 2. The regeneration method is carried out similarly to the method described in example 1, but drying is carried out at a temperature of 150 ° C for 9 hours.

The soap formed during processing with a solution of caustic soda is very easily washed off with water, unlike the mixture of alkaline reagents used in the prototype, which speeds up the process of washing with steam condensate from traces of alkali and soap and increases the degree of purification of the catalyst to 100%.

With the proposed method of catalyst regeneration, no ablation of the palladium precious metal by the washing composition occurs, as a result of which the catalyst service life is not reduced.

Thus, when using the claimed technical solution, the time of the regeneration process is reduced, which increases the productivity of the hydrogenation process.

Also, the proposed method in comparison with the prototype can significantly reduce the cost of reagents for washing the catalyst and energy costs, as it reduces the time of the regeneration process.

Claims (1)

The method of regeneration of spent palladium-containing catalyst for hydrogenation of vegetable oils and fats by treating it with sodium hydroxide solution and washing with condensate, characterized in that the catalyst is pre-washed with steam condensate until there are no traces of fat while hydrogen is sparged with hydrogen, and the treatment is carried out with a 10% sodium hydroxide solution while blowing with hydrogen, then washed with steam condensate until there is no trace of alkali and soap and dried in a stream of hydrogen and at 145-150 ° C for 8-9 hours.