RU2417121C1 - Method of producing catalyst - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to sorption, particularly, to production of sorbent-catalysts for individual protection means. Proposed method comprises impregnating active coal from compacted vegetable stock including fruit-tree stones and/or nutshells with micro pore volume of 0.58-0.85 cm³/g heated to 70-90°C, with solution including compounds of chromium, copper, silver and triethylenediamine, cured for 2.5-3.5 hrs, thermal treatment at 120-135°C with increment in rise rate of 5-10°C/min, and curing for 0.3-0.8 h.

EFFECT: longer life of catalyst particularly in small-length layers, improved operating performances.

2 cl, 3 ex

Description

The invention relates to the field of sorption technology, in particular to the preparation of sorbent catalysts by impregnating activated carbon with solutions of catalytic additives for use in collective and individual protective equipment in order to remove toxic substances (OM) from the air, as well as protect the environment from industrial emissions.

A known method of producing a sorbent catalyst by impregnating a metal-containing activated carbon with an aqueous solution of potassium dichromate and triethylenediamine (TEDA) in the ratio: potassium dichromate: TEDA = 1: (0.04 ÷ 0.08), aging for 1.5-1.8 hours and subsequent heat treatment at 110-140 ° C with a rate of temperature rise of 3-8 ° C / min (see RF patent No. 2108149, publ. 10.04.98, class C01B 31/08).

A disadvantage of the known method is that the resulting catalyst is characterized by low storage stability and poor activity in thin layers, i.e. layers of small length.

Closest to the proposed technical essence and the number of matching features is a method for producing a catalyst, comprising treating activated carbon with a micropore volume of 0.40-0.55 cm ³ / g of an impregnating solution with a metal concentration of 10-16% and subsequent heat treatment at a temperature of a layer equal to 120-135 ° C (see US patent No. 4801311, publ. 05.01.89 g., CL 01/31, B01J 20/20, B01J 21/18).

The disadvantage of the prototype is the short time of the protective effect of the catalyst on cyanide in layers of short length.

The technical result of the invention is to increase the time of the protective effect of the catalyst layer on cyanide in short layers.

The high protective time of the catalyst for cyanide chloride allows you to create reliable means of protecting the respiratory system from toxic gases, especially individual ones, with better performance characteristics, in particular, with a minimum weight and low breathing resistance.

The specified technical result is achieved by the proposed method, including the impregnation of activated carbon from compacted plant material containing fruit tree bones and / or nutshells with a micropore volume of 0.58-0.85 cm ³ / g, a solution containing compounds of chromium, copper, silver and triethylenediamine, activated carbon is heated to 70-90 ° C before impregnation, while it is aged for 2.5-3.5 hours, and heat treatment is carried out at a temperature of 120-135 ° C at a rate of rise of 5-10 ° C / min and exposure for 0.3-0.8 hours.

The difference between the proposed method and the prototype is that as activated carbon, coal is taken from compacted plant material containing fruit tree bones and / or nutshells with a micropore volume of 0.58-0.85 cm ³ / g, which is heated before impregnation up to 70-90 ° C, and aging is carried out for 2.5-3.5 hours and heat treatment is carried out at a rate of temperature rise of 5-10 ° C / min, followed by aging of the catalyst 0.3-0.8 hours.

From the scientific, technical and patent literature, the authors are not aware of the above-described method for producing a catalyst.

The essence of the proposed method is as follows.

When toxic substances are absorbed from the air by the catalyst in small layers, good contact of the catalyst with the poisonous substance should be ensured, which is achieved, first of all, with a uniform distribution of catalytic additives, the presence of a large volume of adsorption centers and the absence of obstacles to remove non-toxic decomposition products of toxic substances. On the other hand, it is necessary to form such a catalytic complex in the catalysts that will ensure the complete removal of toxic toxic substances in all operating modes of protective equipment.

As a result of numerous studies, it was found that the use of activated carbons from compacted plant materials, characterized by a natural ultra-porous structure with a high micropore volume and especially their preliminary heating, provides not only the presence of large amounts of adsorption centers, but also determines the uniformity of the location of additives. It was found that the rate of temperature rise during the heat treatment of impregnated carbon particles has a significant effect on the quality of the resulting catalysts. Another important technological factor in improving the quality of the catalyst was the exposure time during heat treatment.

The final modes of obtaining the proposed catalyst were established empirically.

The method is as follows. Activated charcoal is taken from the seeds of fruit trees and / or nutshells with a grain size of 0.5-1.5 mm and a micropore volume of 0.58-0.85 cm ³ / g. In the reactor, an impregnation solution is prepared with a concentration of catalytic additives, wt.%:

- copper - 7.5-8.5;

- chromium - 3.0-4.0;

- silver - 0.10-0.15;

- TEDA - 2.5-3.5.

Coal is heated to 70-90 ° C, loaded into an impregnation apparatus and the drum is turned on for 25 minutes. Then wet coal is unloaded on baking sheets and aged 2.5-3.5 hours, after which the product is heat-treated in an atmosphere of air in a KS furnace when the temperature rises to 120-135 ° C at a speed of 5-10 ° C / min with holding at final temperature 0.3-0.8 hours.

The finished catalyst is discharged from the furnace and sent for testing.

The sorption activity of the catalyst for cyanide is determined on a device DP-2 BP 4910500 under the following conditions:

- the concentration of vapor of cyanide chloride - 5 mg / l;

- the length of the catalyst layer is 2.0 cm

Obtained by the proposed method, the catalyst had a protective time of 32-56 minutes.

The following examples illustrate the invention.

Example 1

1.25 liters of distilled water and 1.2 liters of ammonia water are poured into a 5-liter reactor. The solution is heated to 40 ° C, then 312 g of carbon dioxide of basic copper (in terms of copper 7.9%), 268 g of potassium dichromate (in terms of chromium 3.9%) are introduced into the container, then silver nitrate in an amount of 4 is added. 8 g (in terms of silver 0.12 wt.%) And TEDA in the amount of 75 g (3.0 wt.%).

2.5 kg of activated carbon of the VSK brand (TU 2568-195-04838763-2007) from coconut shell with a grain size of 0.5-1.5 mm and a micropore volume of 0.58 cm ³ / g (75%) is loaded into the impregnation apparatus from the total pore volume), preheated to 70 ° C.

Activated carbon is poured with the prepared impregnating solution and the rotation of the drum is turned on. Soaking time is 30-40 minutes.

After impregnation, the unloaded grains are aged for 2.5 hours and sent to a fluidized bed furnace (CC), supplying heated air to the product layer. The rate of rise in air heating temperature is 5 ° C / min.

The heat treatment time is 0.3 hours. Then the product is unloaded in a special metal container and sent for testing. The resulting catalyst in a 2.0 cm layer was characterized by a protective action time for cyanide chloride of 32 minutes.

Example 2

The process is carried out as in example 1, except that the initial coal of the MeKS brand (TU 2568-302-04838763-2007) from peach seeds was heated before impregnation to a temperature of 90 ° C, the aging time of the impregnated product was 3.5 hours, heat treatment was carried out by treating coal at a temperature of 135 ° C. The rate of temperature rise was 10 ° C / min, and the shutter speed was 0.8 hours. The resulting catalyst in a 2 cm layer had a protective effect on cyanide chloride of 56 minutes.

Example 3

The implementation of the process as in example 1, except that as a basis take coal from apricot kernels, plums and walnut shells with a micropore volume of 0.75 cm ³ / g and heat to 80 ° C.

The impregnated coal was aged for 3 hours, the heat treatment temperature was 127.5 ° С, and the temperature was raised at a rate of 7.5 ° С / min, the exposure time during heat treatment was 0.55 hours.

The resulting catalyst had a protective effect on cyanide chloride in the layer of 2 cm for 42 minutes.

The experiments showed that only the use of activated carbons from compacted plant materials with a micropore volume of 0.58-0.85 cm ³ / g provides the possibility of obtaining a catalyst with increased activity on cyanide chloride. A decrease in micropore volume (less than 0.58 cm ³ / g) leads to a deterioration of the catalyst due to a decrease in adsorption centers, while an increase in micropore volume in such coals (more than 0.85 cm ³ / g) leads to a decrease in the strength of the catalyst.

Heating the coal before impregnation helps to remove water vapor (or other adsorbed molecules, such as carbon dioxide), which leads to additional penetration of additives into the internal volume of the adsorbent. The optimal impregnation temperature is 70-90 ° C. A decrease in temperature (below 70 ° C) provides insufficient removal of the vapor of adsorbed water molecules and carbon dioxide, and an increase (above 90 ° C) leads to particle cracking and loss of strength.

The aging (curing) of impregnated activated carbon is also an important technological parameter in the formation of a highly active catalytic complex. Thus, a decrease in the exposure time of less than 2.5 hours leads to aggregation (sticking) of coal particles, and an increase of more than 3.5 hours leads to the restoration of the impregnating compounds to a metallic state.

Another undoubtedly important factor leading to an increase in the activity of the catalytic complex is the rate of temperature rise during heat treatment. The heating rate above 10 ° C / min, leads to the destruction of the catalytic complex, and below 5 ° C / min, without leading to a significant increase in the activity of the catalyst, is not economically feasible.

The duration of the heat treatment, comprising 0.3-0.8 hours, is optimal in the formation of the catalytic complex. An exposure time of less than 0.3 hours leads to wetting of the resulting product, and an increase of more than 0.8 hours leads to the destruction of the complex.

The catalyst manufactured by the prototype method (US Pat. RF No. 2228902) showed the time of the protective action of cyanide in similar test conditions for 12-20 minutes. Obtained by the proposed method, the catalyst based on activated carbon from compacted plant materials has a sorption activity on cyanide chloride 2.0-2.5 times higher than the prototype, which will allow you to change the weight and size parameters of the final products when using it and to modernize modern means of personal respiratory protection.

From the foregoing, it follows that each of the features of the claimed combination to a greater or lesser extent affects the achievement of a technical result, namely, increase the time of the protective action of the catalyst on cyanide in small layers, and the entire population is sufficient to characterize the claimed technical solution.

Claims (2)

1. A method of producing a catalyst, including the impregnation of activated carbon with a solution containing compounds of chromium, copper, silver, triethylenediamine, subsequent aging and heat treatment at a temperature of 120-135 ° C, characterized in that the activated carbon is taken from compacted plant material containing seeds of fruit trees and / or nutshells, with a micropore volume of 0.58-0.85 cm ³ / g, which is heated to 70-90 ° C before being impregnated, and aging is carried out for 2.5-3.5 hours and heat treatment lead at a rate of temperature rise of 5- 10 ° C / min. 2. The method according to claim 1, characterized in that during heat treatment, the catalyst is incubated for 0.3-0.8 hours