SU348033A1 - Method of regenerating rhodium-containing catalyst - Google Patents

Description

The invention relates to the field of the regeneration of catalysts, in particular the rhodium-containing 1, of its catalyst for the alkylation of water-vapor alkylbenzenes.

A known method of regeneration of catalysts containing platinum group metals, by treating them at elevated temperature with an oxygen-containing gas mixture, such as flue gases. However, this method turned out to be peyrydny for rheon-containing catalysts.

To increase the service life of the catalyst, a hydrogen-containing gas, hydrogen or a mixture of it with water vapor is taken as a gas mixture, and the treatment is carried out at 300-550 ° C and a pressure of not more than 20 atm. At the same time, the catalyst activity is restored and a constant yield of dealkylation products is maintained for 5-6 months or more.

The volumetric flow rate of hydrogen is 300-3000 hours. The volumetric flow rate of water is 0.3-3 hours.

The greatest effect of regeneration is achieved if the duration of the reaction period does not exceed 120 hours. The duration of regeneration is 5-30 hours. The method is inapplicable if the catalyst poisoning is caused by sulfur compounds much more.

Not only technical hydrogen can be used for regeneration, but also hydrogen-containing gases, such as gas blown off from a catalytic reforming unit, OR gas formed as a by-product in the dealkylation process itself.

The treatment of the catalyst with hydrogen can be carried out on the duct through the reactor or with recirculation, in the latter case, the cost of hydrogen for steam heating is minimal.

Example 1. Dealkylation of steam with toluene is carried out in the presence of a catalyst, containing 0.6% Rh, 1.8% 1x20 on Y-АБОз.

CONDITIONS OF DEKYL EXPERIENCE — the volumetric feed rate of toluene is 1 h; the molar ratio of water: toluene is 4: 1, the pressure is atmospheric, the temperature is 460 ° C.

Every 90 hours of the reaction flow, the supply of raw material is stopped and the catalyst is purged with hydrogen supplied at a volumetric rate of 650 hours at. Duration of purging 10 h.

The efficiency of the regeneration is visible from the data presented in the table.

With periodic catalpator purges with hydrogen, the yield of benzene was able to be kept almost constant for 6 months during the catalyst's psychic period.

Extension1 body110980270

catalyst operation, h

The output of benzene, weight. % 45.9 / 47.8 45.7 / 47.4 46.0 / 48.2 before / after regeneration

Example 2. Dealkylation of toluene is carried out in the presence of a catalyst containing 0.6% rhodium, 0.1% copper on ABOZ at 460 ° C and a pressure of 5 atm. Toluene is fed at a volumetric rate of 1; molar water: toluene is equal to 6. In 80 hours of testing under the specified conditions, the yield of benzene per lost toluene decreases from € 53 to 48 weight. % The catalyst was regenerated at 460 ° C and a pressure of 5 atm. By purging with a mixture of hydrogen and water vapor. Hydrogen

served with a mass speed of 700, and water - with a bulk velocity of 1. After this purge, the yield of benzene reaches 53 wt. %

Claims (1)

Invention Formula The method of regenerating a rhodium-containing catalyst for the alkylation of alkyl benzenes with steam at an elevated temperature by passing a gas mixture through the catalyst, characterized in that hydrogen or gas is used as a gas mixture to increase the service life of the catalyst steam, and the treatment is carried out at a temperature of 300-550 ° C and a pressure of not more than 20 atm.