RU2150321C1 - Method of activation of sorbent-catalysts - Google Patents

Abstract

FIELD: chemical technology, sorbents. SUBSTANCE: invention relates to sorbent technique and can be used for regeneration of catalytic activity of sorbent-catalysts inactivated in the process of prolonged storage. Invention proposes method of activation of sorbent-catalysts that involves preparing ammonia solution, addition copper and chrome salts as catalytic additions to heated solution, treatment of inactive sorbent-catalyst with prepared impregnating solution and its thermotreatment. Ammonia solution containing 10-25 wt. % of ammonium carbonate and added copper and chrome salts is diluted with water to ammonium carbonate content 3-15 wt.%, then 1-5 wt.% of alkaline metal carbonate is added and thermotreatment is carried out at 100-250 C. Method ensures to regenerate catalytic activity up to the parent level by poorly sorbing impurities. EFFECT: improved method of activation. 5 ex

Description

 The invention relates to the field of sorption technology and can be used to restore the catalytic activity of sorbent-catalysts deactivated during long-term storage. Regenerated sorbent-catalysts can be used in industrial gas purification processes or in respiratory protective equipment.

 The literature describes a method for the chemical regeneration of activated carbons by treatment with a 1-2% NaOH solution followed by drying (see A.D. Smirnov "Sorption water purification", L., 1982, pp. 112-116).

 A known method of producing a sorbent, comprising impregnating granules of activated carbon with a solution of a metal salt (copper, chromium, silver, nickel or iron) or a mixture thereof followed by heat treatment (RU 2023660 C1, 11/30/1994).

A known method of producing a sorbent-catalyst, including the impregnation of activated carbon with a solution of catalytic additives containing 8 to 16% carbon dioxide, 10 to 25% copper cupranate, 2 to 5% chromium with a ratio of carbon-impregnating solution 1: 0.5 to 0.9, and heat treatment at 155 - 190 ^o C (RU 2083274 C1, 07/10/1997).

 The use of known methods for the preparation and regeneration of catalysts and coals does not lead to a complete restoration of the activity of sorbent catalysts for poorly absorbed toxic impurities.

The closest in technical essence and the achieved results is a method of regeneration of sorbent-catalysts by treating them with a chemical reagent, ammonia water containing 8 - 20% carbon dioxide is taken as a reagent with a ratio of sorbent-catalyst and ammonia water 1: (0.4 - 0, 7), and then heat treatment is carried out at 120 - 200 ^o C in a fluidized bed furnace (RU 2088524 C1, 08.27.1997).

 The disadvantage of the prototype is the instability of the restored sorbents during long-term storage.

 The objective of the invention is to restore the initial activity of the sorbent catalysts for poorly sorbed substances after their long storage.

This goal is achieved by the proposed method of activating sorbent-catalysts, including the preparation of an ammonia solution, introducing catalytic additives in the form of copper and chromium salts into the heated solution, treating the sorbent-catalyst that has lost activity with the prepared impregnating solution, and heat treating it, characterized in that the ammonia solution containing 10 - 25 wt. % ammonium carbonate is heated to 40 - 80 ^o C, after the introduction of salts of copper and chromium it is diluted with water to the content of ammonium carbonate 3 to 15 wt. % and add to it 1 to 5 wt.% alkali metal carbonate, and heat treatment is carried out at 100 - 250 ^o C.

 From the scientific and technical literature, the authors are not aware of the use of alkali metal carbonates, the sequence of operations in the preparation of the impregnating solution, and the temperature regime of heat treatment.

 The essence of the proposed method is as follows.

 During the long-term storage of sorbent catalysts, which are activated carbons coated with impregnation and heat treatment with catalytic complexes of copper, chromium, etc., the active components go into crystalline form and, as a result, the activity of the sorbent catalyst is lost.

As a result of numerous experiments, it was possible to establish that the order of preparation of the impregnating solution, the conditions of impregnation and heat treatment, and, when the salts are dissolved first in a hot concentrated solution (NH ₄ ) ₂ CO ₃ and then diluted with water, are of decisive importance when restoring deactivated centers, the chemical reaction proceeds quickly and with a high degree of conversion of reagents. As a result, active ammonia-carbonate complexes are formed, the stability of which is further ensured by the introduction of alkali metal carbonates (potassium or sodium).

 The method is as follows.

A 10-25 wt.% Solution of ammonium carbonate is poured into a separate reactor, heated to 40 - 80 ^o C, and basic carbon dioxide and Cu ⁺⁶ compounds (for example, potassium dichromate) are loaded with stirring in order to obtain 1 - 5 wt. % copper and 0.2 to 1.0 wt.% chromium. After dissolving the solid reagents, which usually takes 5 to 20 minutes, the solution is diluted with water to an ammonium carbonate content of 3 to 15%, and then 1.0 to 5.0 alkali metal carbonates (potassium or sodium) are added.

A deactivated sorbent catalyst is taken and placed in a concrete mixer impregnation apparatus, then, with stirring, an impregnation solution is supplied in the ratio (wt.) Of the sorbent solution 1: 0.3 - 0.6. Then the impregnated sorbent is discharged into the receiving hopper of the fluidized bed furnace, and then heat treatment is carried out with a gas-air mixture at 100 - 250 ^o C.

 As a gas-air mixture, natural gas combustion products in a mixture with air are used.

 The finished product is unloaded in a sealed container and analyzed. The resulting sorbent catalyst has a high dynamic activity of hydrocyanic acid.

 Example 1

An impregnation solution is prepared as follows. 100 l of an ammonia 10% solution of ammonium carbonate are poured into a heated reactor and heated to 40 ^° C, then 3.6 kg of basic copper carbonate CuCO ₃ • Cu (OH) ₂ and 2.3 kg of potassium dichromate are loaded with constant stirring. After dissolving the solid phase, 100 l of water are poured into the reactor, and a solution is obtained with a content of 5% ammonium carbonate, 1% copper and 0.2% chromium (hexavalent). Then 2 kg of potassium carbonate are added. The temperature of the solution in the process of dilution and loading of salts support 40 ^o C.

Take 100 kg of deactivated sorbent-catalyst, obtained on the basis of activated carbon AG-3, containing 4.8% copper, 1.5% chromium and having a protective effect on prussic acid - 28 min, and placed in a concrete mixer. 50 L of the impregnating solution are poured through the metering unit, mixed for 5-10 minutes and discharged into the receiving hopper of the fluidized bed furnace. Next, heat treatment is carried out at a temperature of 100 ^o C to remove excess moisture and ammonia. The resulting sorbent is discharged and the dynamic activity of hydrocyanic acid is evaluated.

The determination of the dynamic activity of hydrocyanic acid is carried out on a dynamic instrument under the following test conditions: concentration of hydrocyanic acid vapor - 3.0 mg / l; the height of the sorbent layer is 3 cm, the specific volumetric flow rate of the vapor-air mixture is 0.5 l / min • cm ² ; relative humidity - 50%.

 The resulting sorbent catalyst had a dynamic activity of 40 minutes

 Example 2

Prepare a solution as in example 1, except that they take a 20% solution of ammonium carbonate, and the dissolution process is carried out at 80 ^o C, while the heat treatment is carried out at 250 ^o C.

 The resulting sorbent catalyst had a dynamic activity of 43 minutes

 Example 3

The solution is prepared as in example 1, except that they take a 20% solution of ammonium carbonate, the dissolution process is carried out at 80 ^o C, and after dilution with water, 10 kg of sodium carbonate are added. Heat treatment is carried out at 200 ^o C. The resulting sorbent catalyst had a dynamic activity of 51 minutes

 Example 4

A solution is prepared as in Example 1, except that a 25% solution of ammonium carbonate is taken, the dissolution process is carried out at 80 ^° C, and after dilution with water, 8 kg of potassium carbonate are added. Take a sorbent catalyst with dynamic activity of hydrocyanic acid - 26 min and carry out the impregnation and heat treatment as in example 1, except that the temperature in 5 sections set 180 ^o C.

 The resulting sorbent catalyst had a dynamic activity of 49 minutes

 Example 5

Take a sorbent catalyst with a dynamic activity of 30 minutes Prepare a solution as in example 2, and heat treatment is carried out at 120 ^o C.

 The resulting sorbent catalyst had a dynamic activity of 53 minutes.

As follows from the above examples, as a result of treating a deactivated sorbent-catalyst with an impregnating solution prepared by the proposed method and heat treatment at 100 - 250 ^o C in a fluidized bed furnace, the activity of the catalyst for poorly adsorbing substances (for example, hydrocyanic acid) is restored to 30 - 40 %

 It follows from the foregoing that each of the features of the proposed combination to a greater or lesser extent affects the achievement of the task, namely, the restoration of the activity of sorbent-catalysts after prolonged storage, and the entire population is sufficient to characterize the proposed technical solution.

Claims (1)

A method of activating sorbent-catalysts, including preparing an ammonia solution, introducing catalytic additives in the form of copper and chromium salts into the heated solution, treating the sorbent-catalyst that has lost activity with a prepared impregnating solution, and heat treating it, characterized in that the ammonia solution containing 10-25 wt. % ammonium carbonate is heated to 40-80 ^o C, after the introduction of copper and chromium salts it is diluted with water to the content of ammonium carbonate 3-15 wt.% and add to it 1-5 wt.% alkali metal carbonate, and thermoset work lead at 100-250 ^o C.