SU390821A1 - WAYS OF INCREASING THE ACTIVITY OF THE CRUKING ALYUMOSILICATE CATALYST - Google Patents

Description

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The known method of increasing the activity of the aluminosilicate cracking catalyst is that the initial aluminosilicate is dried at 200 ° C, kept in vacuum at a residual pressure of 1 mm Hg. Art., then pour a solution of a salt of a modifying metal, such as molybdenum, after which the catalyst is dried first at room temperature, then at 120 ° C and calcined at 550 ° C. However, the known method is difficult to implement, in addition, the resulting catalysts have not sufficiently high quality.

The aim of the invention is to obtain a strong, with an increased specific weight, aluminosilicate catalyst with improved activity, selectivity, reduced coke formation, which makes it possible to synthesize the target products in a high yield. To achieve this goal, it is proposed to use potassium aluminates or their mixtures with salts that easily hydrolyze from water vapor at temperatures up to 200 ° C as a modifying additive for the metal compound.

The proposed method consists in the following.

Microspherical aluminosilicate catalyst after operations of syneresis, activation and washing is processed

2

a weak solution of potassium aluminates or mixtures thereof with salts. The amount of modifier in terms of potassium take no more than 0.5 weight. %, and the amount of active oxide (alumina) 8-20 weight. % depending on the quality of the catalyst. The process is carried out at 40-50 ° C and continuous stirring. The end of the operation is determined by bleaching phenolphthalein in suspension. The solution from the catalyst is separated by decanting. The lower catalyst layer is transferred to an apparatus and clamped between two grids. The hydrolysis of aluminates and salts is carried out with water.

steam at 170-200 ° C or hydrolyzing agents. The amount of steam, twenty times stoichiometric, is fed to the catalyst for the hydrolysis reaction. The end of the hydrolysis operation is determined by the activity

catalyst or analysis of potassium in solution. The catalyst is dried for 5 hours with a uniform rise in its temperature to 580 ° C.

PRI me R. For the experiment take

microspheric aluminosilicate catalyst, processed (syneresis, activation and washing); potassium aluminate solutions (CsAH2 and K2HA1Oz) prepared from aluminum trihydrate and potassium oxide hydrate with a concentration of 0.1-8%; ammonium alumina, ammonium aluminum, ammonium sulfate; distilled water.

The catalyst in the form of a suspension, which underwent all types of processing, except for drying and calcining, was delivered in 5-liter flasks to the laboratory of physico-chemical studies, where the decantation was performed, and water was removed. A calculated amount of a solution of potassium aluminates or their mixtures with salts is poured into the catalyst. The solutions are introduced into the suspension with temperature, phenolphthalein is added dropwise, and the temperature of the suspension is maintained at 45-50 ° C in a thermostat. Air is continuously supplied to stir the suspension. Over time, the color intensity of the solution decreases and, with a slightly pink or colorless solution, the process for the introduction of salts is considered smoked. The suspension is decanted from the water. The precipitate after decanting is transferred to the lower grid of the apparatus, covered with a grid on top and treated with water vapor with a temperature of 170-200 ° C for 2-2.5 hours.

Instead of treating the catalyst with steam, it is treated with hydrolyzing agents such as ammonium hydroxide, ammonia, etc. The consumption of water vapor is 10-30 times the stoichiometric amount of the reaction of the hydrolytic decomposition of salts.

The catalyst is dried at PO-120 ° C in a thermostat to obtain a constant weight. The calcining is carried out in a muffle furnace with a smooth rise in temperature up to 580 ° C.

As a result of research, it was found that the addition of potassium aluminates, as well as their mixtures, improves the quality of the aluminosilicate catalyst by a1 activity and by 2-2.5 points (by reducing the content of H of methane, increasing the amount of C3 and C hydrocarbons); on selectivity to 56-58%; by

reduction of carbonization by 50-55%. It is possible to work at temperatures up to 700 ° C with a moisture content of the raw material up to 4-5 weight. % strength increases by 12-15%.

The optimal amount of potassium salts in terms of potassium is not more than 0.5 weight. %, the amount of oxy aluminum depends on the technical requirements for the catalyst.

Subject invention

A method for increasing the activity of an aluminosilicate cracking catalyst by depositing a metal compound additive on its surface, characterized in that, in order to increase the yield of the target products, decrease Coke formation and increase the strength of the catalyst, potassium aluminates or their mixtures with SALTS, which easily hydrolyze from water vapor at 170–200 ° C.