RU2102137C1 - Method of producing nickel catalyst for hydrogenation - Google Patents

Abstract

FIELD: heterogeneous catalysts. SUBSTANCE: method involves precipitation of nickel salt on a carrier with soda ash which is poured in gradually to 10-15% nickel salt solution followed by filtration, washing, drying and reduction in hydrogen-containing gas and passivation with nitrogen-air mixture. Precipitation is carried out from 20-30% suspension containing nickel salt and soda ash at mole ratio to nickel salt = 1.0-1.5 simultaneously. Activity of the obtained catalyst in the process of oils and fats hydrogenation is increased by 30-40%. EFFECT: increased activity of catalyst, simplified technology, decreased water consumption. 1 tbl

Description

 The invention relates to the field of preparation of heterogeneous catalysts used in hydrogenation processes.

 A known method of preparing precipitated catalysts, comprising dissolving the original salt, followed by precipitation / 1 /.

A known method of producing a catalyst for the hydrogenation of organic compounds by precipitation of compounds from a solution of 10% nickel sulfate with soda with the addition of kieselguhr, followed by processing, including stages of filtration, washing, drying, calcining at 380-420 ^o C, tableting and reduction in the atmosphere of a hydrogen-containing gas / 2 /.

 The disadvantage of this method is the low activity of the resulting catalyst and the high consumption of water when washing the precipitated mass of the catalyst, which entails the formation of wastewater containing heavy metal.

The closest technical solution in essence and the achieved effect is a method of preparing a catalyst for the hydrogenation of vegetable oils and fats by precipitating nickel on a carrier from a 10-12% aqueous solution of nickel sulfate with a 30% sodium carbonate solution, followed by washing, drying, and reduction in a hydrogen-containing gas at 350-500 ^o C and passivation with a nitrogen-air mixture / 3 /. Moreover, the soda ash solution is added to the nickel salt solution with stirring at a speed of 10-20 ml / min.

 The disadvantage of this method is the low activity of the catalyst in the hydrogenation of unsaturated bonds in vegetable oils (≈50%).

Along with this, a large amount of wastewater is formed during the preparation, and the catalyst itself contains impurities; non-washed catalytic poisons; SO ions $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ and Na ⁺ .

 The present invention is aimed at increasing the activity of the Nickel catalyst in the hydrogenation of vegetable oils and fats and simplifying the technology of preparation of the catalyst.

 This technical effect is achieved by precipitation of the main nickel carbonate on kieselguhr from a more concentrated solution of nickel sulfate in the presence of soda ash, with a molar ratio of soda to nickel salt equal to 1.0-, 1.5.

 The invention is illustrated by the following examples.

Example 1. Prepare 1 l of a suspension containing 60 g of salts: NiSO ₄ • 7H ₂ O 400 g, nickel sulfate Na ₂ CO ₃ 266 g and SiO ₂ 74 g.

For precipitation, the suspension is heated to 85 ^o C and stirred until the pH reaches 9-10. The resulting mixture was poured with distilled water (1 l) and decanted, after which it was filtered. The resulting precipitate is washed from SO ions $\genfrac{}{}{0ex}{}{\text{-}}{\text{4}}$ and Na ^{+ with} distilled water, dried, reduced in hydrogen at 400-420 ^o C for 2 hours, then passivated for 5 hours with a nitrogen-air mixture at a temperature of not more than 100 ^o C. The resulting catalyst in an amount of 150 g contains 55% Ni. The activity of this sample in the hydrogenation of sunflower oil is determined by the following method.

где A степень насыщения,
П $\genfrac{}{}{0ex}{}{\text{60}}{\text{0}}$ показатель преломления исходной смеси триглицеридов при 60^oC;
П $\genfrac{}{}{0ex}{}{\text{60}}{\text{г}}$ показатель преломления гидрогенизата при 60^oC;
1,4470 показатель преломления полностью гидрированной смеси триглицеридов (тристеарина) при 60^oС.50 g of refined sunflower oil and 0.15 g of catalyst fraction ≤0.9 μm are placed in a glass reactor. Next, raise the temperature to 200 ^o C, sparging hydrogen at a speed of 3 l / h for 1 hour. The progress of the process and the depth of hydrogenation are controlled by decreasing the refractive index of the hydrogenate compared to the starting oil. The degree of saturation of ethylene bonds of a mixture of triglycerides (A) is determined by the formula:

where A is the degree of saturation,
P $\genfrac{}{}{0ex}{}{\text{60}}{\text{0}}$ the refractive index of the initial mixture of triglycerides at 60 ^o C;
P $\genfrac{}{}{0ex}{}{\text{60}}{\text{g}}$ the refractive index of the hydrogenate at 60 ^o C;
1.4470 refractive index of a fully hydrogenated mixture of triglycerides (tristearin) at 60 ^o C.

The degree of saturation of the obtained hydrogenate was 78.0%
The remaining catalyst samples were obtained by analogy with example 1. The test results of these samples in the hydrogenation of sunflower oil are shown in the table.

As can be seen from the table, the inventive method of preparing a Nickel catalyst allows you to increase the activity in the hydrogenation of vegetable oils and fats by 30-40%
During deposition under the indicated conditions (at a high concentration of the starting salts in the solution), sulfate and sodium ions are not embedded in the structure of the obtained basic nickel carbonate, which makes it possible to reduce the water consumption for washing the deposited mass from these catalytic poisons by about 10 times.

 In addition, the method allows to simplify the deposition technology through the use of a more concentrated solution, excluding the stage of dosing and preparation of sparingly soluble sodium carbonate.

 The inventive method is planned to be implemented at enterprises producing nickel-gelselgur catalyst for the hydrogenation of vegetable oils and fats (Ufa refinery and Novokuybyshevsky petrochemical plant).

Claims (1)

 A method of preparing a nickel catalyst for the hydrogenation of vegetable oils and fats by precipitation of nickel sulfate on kieselguhr with soda ash followed by filtration, washing, drying, reduction in a hydrogen-containing gas and passivation with a nitrogen-air mixture, characterized in that the precipitation is carried out from 20 to 80% suspension containing simultaneously nickel sulfate and soda ash in a molar ratio of soda nickel sulfate equal to 1.0 to 1.5.

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