SU1641418A1 - Catalyst for cleaning air of carbon monoxide and method for its manufacture - Google Patents

Abstract

This invention relates to catalytic chemistry, in particular to the preparation of a contact for air purification from carbon monoxide. In order to increase contact activity and reduce heat generation during cleaning, it contains the following components in wt.%: Manganese dioxide 14-18; alumina restuated on 25–27 wt%. The contact is obtained by applying manganese dioxide from an aqueous solution of manganese nitrate containing 0.59-0.89 g / ml Mp MOOBNaO on mordenite. The application of lead by impregnation at a ratio of solid and liquid phases of 10: 3, providing the specified mass content of the components in contact. 2, p. F-ly, 5 tables.

Description

The invention relates to a method for obtaining contacts used for air purification using industrial gas masks, including in emergency situations, as well as for cleaning indoor air from toxic impurities, in particular carbon monoxide.

The purpose of the invention is to increase contact activity and reduce heat generation during cleaning due to the content of mordenite dealuminated to a certain degree as a zeolite at a certain ratio of components, as well as due to the use of a certain concentration of an aqueous solution of manganese nitrate and contact manganese dioxide on the dealuminated mordenite. under certain conditions.

EXAMPLE 1 To obtain activated (partially dealuminated) mordenite to 100 to mordenite rock, 3-5 mm grained, composition, wt.%: SIO2 64.56, TYu 0.23, 12.02, Rv20z 0, 95 FeO 0.83, MpO 0.10, MDO 0.68, Ca 3.58, No. 20 0.94, KaO 2.03, P20s 0.07, H20 14.01, poured 125 ml 3 n. solution of HCI and maintained at 92 - 96 ° C and occasional stirring for 2.3 and 4 hours. After that, the granules are washed from distilled SG ions

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water and dried at 110 ° C for 2-4 hours at constant humidity. The obtained samples of activated (partially dealuminated) mordenite have the composition shown in Table 1.

EXAMPLE 2 To prepare a contact, 100 g of dealuminated mordenite (prepared according to Example 1) are added with 30 ml of an aqueous solution of manganese nitrate of various concentrations, prepared from an analytical grade preparation, stirred to ensure uniform impregnation, and dried. in air for 12 hours at 25 ° C and calcined at 350 ° C for 6 hours to decompose manganese nitrate to form MpOa. Depending on the required content of manganese dioxide in contact, the impregnation of mordenite is carried out in one or several stages (followed by drying and calcining) using impregnating solutions of different concentrations.

Testing contact activity in the process of purifying air from carbon monoxide is carried out in a flow type reactor. Below are examples of tests. Test Example 1. 6 g of a contact, previously calcined in a stream of air at 400 ° C for 4 hours and cooled in a desiccator to room temperature, is placed in a reactor and, at a rate of 100 ml / min, an air mixture containing 0.6% is passed through the reactor Soo The adsorption capacity of the contact (cm / g) is determined by the amount of CO absorbed by the unit mass of the catalyst prior to the onset of carbon monoxide penetration through the layer (chromatographic control).

The test results are shown in table 2.

It can be seen from the above data that contacts (samples 4,5,6,10,12), containing mordenite, de-aluminized by 25 - 27%, and manganese dioxide in the amount of 14 - 18%, have the greatest absorption capacity for CO. An increase in the degree of dealuminization of mordenite (up to 27%) does not lead to an increase in the absorption capacity of contacts, and an increase in the content of MnO2 (above 18%) even leads to a decrease in the sorption capacity for carbon monoxide.

The concentration of Mn02i and therefore the concentration of the impregnating solution, the amount of impregnations, has a significant effect on the magnitude of the sorption capacity of the contacts in terms of CO. Naturally, in order to simplify the technology of contact obtaining, the impregnation process is rationally carried out in one stage. However, this requires the use of highly concentrated

manganese nitrate solutions and adversely affect the sorption characteristics of the contact (sample 11). Apparently, this is due to the fact that at high concentrations of manganese nitrate in the impregnating solution there is an uneven deposition of Mn (Mn) 2 on the surface of the modified zeolite, which entails the agglomeration of MpOa at the sample calcining stage. Therefore, when impregnating a zeolite, it is most advisable to use a solution containing not more than 0.89 g of Mn (MO3) and in 1 ml of solution (sample 5) and the use of double impregnation. A decrease in the concentration of manganese nitrate (less than 0.59 r / mg) is inexpedient, leads to the complication of technology (3 impregnations), without proving the positive effect of the sorption properties of the contact.

0 Test example 2. The purification is carried out according to the method described in test example 1 on contact sample 5 (Table 2), but with repeated repetition of the adsorption-desorption process. After the protective time of the layer has expired, the contact is subjected to regeneration by heating it in air flow at 450 ° C for 4 hours. After that, the contact is cooled to 25 ° C and the process of CO adsorption is carried out.

0 The results are shown in table 3.

From the data of Table 3 it can be seen that the magnitude of the adsorption capacity of the contact and the protective time of the layer remain almost unchanged after 9 cycles of regeneration. Thus, the proposed contact can be used in the process of purifying air from CO and then regenerating, during which the contact restores the absorption properties at least 9 times.

0 Test example 3. The cleaning process is carried out according to the method described in test example 1 on contact sample 5 used in test example 2, but with different concentrations of carbon monoxide of the kind in the cleaned air. The degree of air purification from CO (in%) is determined within 30 minutes, and the gas temperature is recorded after passing through the contact layer. For comparison, the process is conducted in

Under the same conditions on a known contact consisting of zinc oxide (67 wt.%) And silver permanganate (33 wt.%). The data are given in table 4. From the data in Table 4 it can be seen

5 that the use of air purification from the CO contact according to the invention makes it possible to reduce the degree of catalytic oxidation by a factor of 4-6 and reduce the temperature of the air being cleaned while maintaining a high degree of purification.

Table 5 shows the results of experiments on the purification of air from carbon monoxide using: a well-known CO absorber (experiment 1), optimal contact using the proposed method (experiment 2), dealuminated mordenite (experiment 3), contact based on synthetic zeolite 13X ( NaX, produced by the State Defense Committee of the VNII NP) (test 4), contact based on dealuminated mordenite, obtained by the ion exchange method (test 5).

From the data of Table 5 it can be seen that the most effective in the process of purifying air from carbon monoxide is a contact containing 16% MpOa. prepared on the basis of dealuminated mordenite. Only at this contact is it possible to completely purify the air of carbon monoxide mainly due to chemisorption bonding with a minimum increase in the gas temperature during the purification process.

Claims (2)

Invention Formula 1, Contact for air purification of carbon monoxide containing manganese dioxide on zeolite, characterized in that, with a chain of increased activity of contact 5 15 0 five 0 This and reduction of heat generation during cleaning, as a zeolite, the contact contains dealuminated 25–27 wt.% mordenite with the following content of components, wt.%: Manganese dioxide14-18 Dealuminated 25-27 wt.% mordenite the rest 2. A method of obtaining a contact for purifying air from carbon monoxide by applying manganese dioxide from a manganese-containing solution to a zeolite, followed by heat treatment, characterized in that, in order to obtain contact with increased activity, an aqueous solution of nitrate is used manganese, containing 0.59 - 0.89 g / ml Mn (MOZ) a, mordenite used as a zeolite, dealuminated at 25 - 27 wt.%, and application is carried out by impregnation at a solid-liquid ratio of 10: 3 by providing present the following contents of components in contact, wt.%: Manganese dioxide14-18 Dealuminium 25-27 wt.% mordenite the rest Table 1 Dependence of the composition of mordenite on the duration of dealumination  The degree of dealumination of the sample Dependence of the content of MpOa in the contact on the conditions of its production and the sorption capacity of the contact in CO Pyrolusite The effect of contact regeneration on the value of its CO adsorption capacity and the protective time of the layer table 2 Table 3 The effect of CO concentration in the gas to be purified on the degree of purification and change in gas temperature Dependence of the degree of purification and the change in gas temperature on the CO concentration in the purified gas for various contacts Table 4 Table 5  Test conditions are similar to Test Example 3, Table 4, except for the duration of the test, which is increased from 30 to 60 minutes. Continuation of table 5