SU952318A1 - Method of producing catalyst for cleaning exhaust gases - Google Patents

Description

The invention relates to a process for the preparation of a catalyst for the purification of waste gases, for example a catalyst for the oxidation of carbon monoxide with molecular oxygen.

Copper-containing catalysts for the purification of exhaust gases from carbon monoxide are known, which are obtained by the methods of mixing, deposition or deposition. The final operation to obtain such catalysts is to heat them at 250-400 ° C. The catalysts are loaded into the reaction apparatus, heated and transferred to the operating mode, feeding the reaction mixture til

The closest to the proposed technical essence and achievable result is a method for preparing a catalyst for purifying waste gases from carbon monoxide by impregnating aluminum oxide with an ammoniac carbonate solution of copper, followed by drying and calcining 2.

A disadvantage of the known catalyst is low activity during the oxidation of carbon monoxide. Thus, with a degree of conversion of carbon monoxide, only 25% is achieved. .

The aim of the invention is to obtain a catalyst with increased activity.

This goal is achieved by the fact that according to the method for producing a catalyst for purifying exhaust gases from carbon monoxide by impregnating an alumina with an ammonia-carbonate solution of copper followed by drying

10 and calcining, the catalyst mass is additionally treated with a reducing gas mixture containing 1-12% by volume of hydrogen and / or carbon monoxide and 88-99; vol.% nitrogen,

15 at 220-280 ° C.

The proposed method allows to obtain a catalyst with increased activity compared to a catalyst obtained in a known manner.

20 Thus, when the degree of conversion of carbon monoxide in the presence of a catalyst obtained by the inventive method is 65%.

According to the invention, calcined 25 with alumina (grade A-1) is impregnated for 1 hour with a constant circulation of an ammonium carbonate copper solution of composition, g / l: Cu 100-200, NHj 110-220, CO 70-140. 30 The excess solution is drained, and the impregnated granules are dried in a radiation dryer at 130-150 0 with constant stirring for 2-4 hours. The next intermediate product is calcined at 500-900s for 4 hours at a rate of temperature rise of not more than 200 degrees / Cooling fines and dust are removed from the catalyst. Then the catalytic mass is loaded into the reactor and a reducing gas mixture consisting of hydrogen and / or carbon monoxide (the amount of reducing agent is not more than 12%) and nitrogen is fed and the temperature starts to rise at a rate of not more than 2 degrees / day. When reaching 220-280 0 the catalyst is kept in the flow of the reducing mixture from 1 to 20 h, after which, the reactor is fed with a working gas mixture containing the following components, vol.% CO 6–8; Oh. - 12-14; NI - 78-81. Example 1 An ammonia carbonate copper solution containing 130 g / l copper, 145 g / l ammonia and 95 g / l carbon dioxide was prepared in a separate container. In this solution, pellets of aluminum oxide (1 l of alumina per 2 liters of solution) are immersed for one hour, while ensuring the movement of the solution around the granules. After impregnation, the granules are dried in a drying oven at 130-150 ° C for 2-3 hours and calcined in a quenching drum at 500 ° C (for 4 hours) .: The cooled catalyst is loaded into the reactor, a reducing gas mixture of the composition, 1% by volume, is fed CO, the rest is nitrogen, and the temperature is raised to 2 50 ° C with an accuracy of 2 K / min. During this temperature, the catalyst is held for 8 hours, then the temperature is reduced to 200 C and the reducing gas is replaced with a working gas (CO 6.0 ; Og 13, 0 vol.%, The rest - nitrogen). PRI mme R 2. Ammonia-carbonate diluent is prepared in a separate capacitance type: unit, - 130 g / l of copper, 145 g / l of ammonia and 95 g / l of carbon dioxide in this solution. The granules are immersed in this solution for one hour. alumina (1 l alumina per 2 l of solution), while ensuring the movement of the solution around the granules. After impregnation, the granules are dried in a radiation dryer at 130–150 ° C for J 2-3 hours and calcined with 5 carbungs in a calcination for 4 hours. The cooled catalyst is loaded into the reactor, the secondary mixture of the composition is understood: 8% by volume CO, the rest is nitrogen and raise temperature up to 280 at a rate of 1 deg / min. At this temperature, the catalyst is held for 1 hour, then the temperature is lowered to and the reducing gas mixture is replaced with a working gas (CO 6.0; Oj - 13.0 vol.%, Nitrogen - the rest). The data of example 3 are presented in the table. Example 4. in a separate tank GQTov t ammonia carbonate solution of copper containing 130 g / l of copper, 145 g / l of ammonia and 95 g / l of carbon dioxide. In this solution, pellets of aluminum oxide (1 l of alumina per 2 liters of solution) are immersed for one hour, while ensuring the movement of the solution around the granules. After impregnation, the granules are dried in a radiation dryer at 130-150 ° C for 2-3 hours and calcined in a quenching drum for 4 hours. The cooled catalyst is loaded into the reactor, a reducing gas mixture of the composition: CO 4 vol.%, Hj - 4 vol.%, nitrogen - the rest and raise the temperature to a speed of 1 deg / min. At this temperature, the catalyst is incubated for 3 hours, then the temperature is lowered to 200 ° C, the reducing gas mixture is replaced with the working one (CO — 6.0; O — 13.0 vol.%, Nitrogen — remaining). Example 5. A ammoniac carbonate copper solution containing 130 g / l copper, 145 g / l ammonia and 95 g / l carbon dioxide was prepared in a separate container. In this solution, the granules of alumina oxide (1 l of alumina per 2 l of solution) are immersed for one hour, while ensuring the movement of the solution around the granules. After impregnation, the granules are dried in a radiant dryer at 130-150Pc for 2-3 hours and calcined in a quenching drum for 4 hours. The cooled catalyst is loaded into the reactor, a reducing gas of the composition: CO 12.0% by volume; nitrogen - the rest and raise the temperature to 280 ° C at a rate of 0.5 deg / min. At this temperature, the catalyst is held for 1 hour, then the temperature is lowered to 2 ° C and the reducing gas mixture is replaced with the working one (CO 6.0; 0 - 13.0% by volume, nitrogen - the rest). Example 6. In a separate container, a silicate-carbonate copper solution containing 130 g / l of copper, 145 g / l of ammonia, 95 g / l of carbon dioxide was prepared. In this solution, pellets of aluminum oxide (1 l of gshyumini oxide per 2 l of solution) are immersed for one hour, while ensuring the movement of the solution around the granules; After impregnation, the granules are dried in a radiation dryer at 130-150 ° C for 2-3 hours and calcined in a quenching drum at 500 ° C for 4 hours. The cooled catalyst is loaded into the reactor, serves recovery

gas mixture of the composition: CO 15 vol.%, nitrogen - the rest and at; take temperature up to a speed of 0.5 deg / min. At this temperature, the catalyst is held for 1 hour, then the temperature is lowered to 5 and the replacement gas mixture is replaced with a working gas (CO 6.0; 0% by volume, the rest is nitrogen)

Example 7. In a separate tank, an E1-carbonate solution was used — a thief of copper, containing 130 g / l of copper, 145 g / l of ammonia and 95 g / l of carbon dioxide. In this solution, pellets of aluminum oxide (1 l of alumina per 2 liters of solution) 15 are immersed for one hour while ensuring the movement of the solution around the granules. After impregnation, the granules are dried in a radiation dryer at 130-150 s for 2-3 h and P1 is molten in a muffle furnace at 900 ° C for 2 hours.

The cooled catalyst is loaded into the reactor, a reducing gas mixture of the composition: CO 8.0 vol.% Else is fed — the temperature is raised to 280 ° C at a rate of 2 K / min. At this temperature, the catalyst is held for 2 hours, then the temperature is lowered to 200 ° C and replaced reducing gas mixture per working (СО 6.0; О - 13.0% by volume, the rest is nitrogen).

The activity of the catalysts is tested in a flow-circulation installation at 120-240 s, the volumetric rate for fresh gas is 15003000 h on the gas mixture of the composition: CO 6-8; O. 12-14 vol.%, Octagic nitrogen.

The test results, depending on the - OT conditions for the preparation and gas treatment of the catalysts are given in the table.

Famous

1 2 3 4 5 6

Offered 92.0 280 21

8.0 As can be seen from the data in the table, alumo-copper samples that are subjected to additional treatment with a reducing gas mixture have a higher degree of oxidation of carbon monoxide. The low content of the reducing agent in the gas mixture (less than 1 vol.%) Significantly increases the reduction time, which is at a CO concentration of 0.5 vol.% 10-12 hours. Increasing the content of the reducing gas in the gas mixture to more than 12% leads to strong exothermic 20

31.

3000

65

38

3000

Claims (2)

92 KIM effects during restoration, which, in turn, leads to the recrystallization of the copper component and ultimately reduces the activity of the catalyst. DETAILED DESCRIPTION OF THE INVENTION A method for producing a catalyst for purifying exhaust gases from carbon monoxide by impregnating an alumina with an ammonia-carbonate solution of copper, followed by drying and calcination, characterized in that, in order to produce a catalyst with a higher activity, the catalyst mass is further subjected to a reducing treatment. a gas mixture containing one to 12 vol.% of hydrogen and / or carbon monoxide and 88–99 o6.% nitrogen, at 220–280 ° C. Sources of information taken into account during the examination 1. Golodets I.I. Heterogeneous catalytic reactions involving molecular oxygen. Kiev Naukova Dumka, 1977, pp.269-294. 2. USSR author's certificate 707598, cl. A 01 j 23/72, 1977, (prototype).