SU1558463A1 - Method of granulating catalyst for oxidizing sulfur dioxide - Google Patents

Abstract

The invention relates to catalytic chemistry, in particular the preparation of a catalyst for the oxidation of sulfur dioxide, which can be used in the production of sulfuric acid. The goal is to increase the activity and mechanical strength of the catalyst. For this, the diatomite is mixed with an alkaline promoter and vanadium pentoxide. Sulfuric acid and a silica solution are successively added to the resulting mass, followed by molding, drying and calcining. The prepared catalyst has a high activity. Thus, the degree of conversion of sulfur dioxide increases from 40 to 41.5-51.0% at 420 ° C and from 87 to 88-89.2% at 485 ° C, the mechanical strength of the catalyst is 1.5-4 kg / cm higher That allows to increase its service life. 1 tab.

Description

The invention relates to methods for the preparation of catalysts, and specifically to methods for the preparation of vanadium catalysts on silica carriers for the oxidation of sulfur dioxide.

The aim of the invention is to obtain a catalyst with increased activity and mechanical strength due to a certain sequence of mixing of the catalyst components, namely, by the introduction of silica gel into the catalyst mass after the introduction of sulfuric acid into its composition.

Example 1. 92 kg of diatomite are loaded into a high-speed mixer and at the same time 4.6 kg are added

 in the form of NaOH and 41.5 kg KOH (56 wt;%). 13.5 kg (90 wt.%) Are dissolved in the resulting solution and 112.0 L (37 wt.%) Are added with vigorous stirring and maintaining the temperature at 35 ° C. Then, 40 kg (40 wt.%) Of silicazole solution and 1.8 kg of surfactant (a mixture of polyethyleneglycol esters of j-youth and dialkylphenols) dissolved in 3.56 l of HjO are added to the resulting mass, mixed, the resulting mass is extruded into . granules with a diameter of 5 mm, dried at 120 ° C and calcined at 500 C.

The composition of the finished catalyst in terms of the oxides of the following, wt.%;

SP

ate

00 4 C &

Si

V205 6.7;

K20

10.3; 2.4; S0

23.0; Si02 8.6 (from silica sol); SiO 49.0 (from diatomite).

The moisture content of the catalyst mass is 41% by weight.

Example 2. 92 kg of diatomite are loaded into a high-speed mixer and 60 l (92.5 kg) of K3V04 solution (potassium o-vanadate solution concentration 297.8 g / l, C ≈ 181.3 g / l, C v 0 116.5 g / l) and 56.9 kg H2SO4 (93 wt. with vigorous stirring and maintaining the temperature of 35. Then to the resulting mass is added 40 kg (40% by weight) of the silica gel solution and 108 kg of surfactant ( a mixture of polyethylene glycol ethers of mono- and dialkylphenyls) dissolved in 3.56 l of bbjO is stirred, the resulting mass is molded by extrusion into granules with a diameter of 5 mm, dried at 120 ° C, and they potassium at 500 ° C.

The composition of the finished catalyst in terms of oxides of the following, wt.% У405 6.8; K20 10.3; S03 23.0; SiOa 8.6 (from silica sol); Si02 51.3 (from diatomite).

The moisture content of the catalyst mass is 41% by weight.

Example 3. Carried out analogously to example 2, but in the preparation of the catalyst using a solution of silica gel with a concentration of 20% SiO,

Thereby, the concentration of potassium o-vanadate solution is 455 g / l (C to ,, g 277 g / l, C yr 5 178 g / l). The composition of the finished catalyst is similar to the catalyst in example 2.

Example 4. It is carried out analogously to Example 2, but in preparing the catalyst, a silica sol solution with a concentration of 30% by weight SiO-j is used, while the concentration of the potassium o-vanadate solution is 360.8 g / l (SC-0 219.6 g / l , 141.2 g / l) The composition of the finished catalyst is similar to the catalyst of example 2.

Example 5. A mixture consisting of 92 kg of diatomite and 13.5 kg (the content of the main substance is 90% by weight) is loaded into a high-speed mixer, 59.3 kg of a solution of potassium bisulfate dissolved in 99.4 l of NgO previously prepared by dissolving are fed. 39.7 kg of potassium sulfate in 22.9 kg (93 wt.%) Of sulfuric acid with vigorous stirring

and maintain the temperature at 35 (it is possible to obtain potassium bisulfate from KOH and H.SO ,,).

Then, 40 kg of a 40% silicosol solution and 1.8 kg of surfactant (a mixture of polyethylene glycol mono- and dialkylphenyl ethers) dissolved in water are introduced into the catalyst mass. The resulting mass is molded by extrusion into granules with a diameter of 5 mm, dried at 120 ° C and calcined at 500 ° C.

The composition of the finished catalyst in terms of oxides following,

Q

0

five

0

five

five

5% by weight: 6.8; 10.3; S03 23.0; Si02 8.6 (from silica sol); Si0.j, 51.3 (from diatomite).

The moisture content of the catalyst mass is 41% by weight.

Example 6 (for comparison, by a known method). 4.6 kg of Na70 in the form of NaOH and 41.5 kg of KOH (56% by weight) are added to 40 kg of silicazole (40% by weight), and the alkalinity of the plant is pH 12. The solution obtained is dissolved 13 , 5 kg (90 wt.%), And then 112.0 l (37 wt.%) H / jSO j are added with vigorous stirring and maintaining the temperature at 35 ° C. Next, in the high-speed mixer, the prepared suspension is mixed with 92 kg of diatomite. The resulting mass is molded by extrusion into granules with a diameter of 5 mm, dried at 130 ° C and calcined at 600 ° C.

The composition of the finished catalyst in terms of oxides of the following, wt.%: V-jOs 6,7; K70 10.3; NaЈ 2,4; S03 23.0; SiO.5 8.6 (from silicazole), SiO 49.0 (from diatomite).

The moisture content of the catalyst mass is 41% by weight.

Catalyst samples prepared in Examples 1-6 are tested in process e for the oxidation of sulfur dioxide to trioxide. The tests were carried out at 420 and 485 ° C, flow rate ha

base mixture 4000 h, the concentration of sulfur dioxide in the mixture with air 10 vol.%. The obtained characteristics of the catalyst samples are presented in the table.

The data presented in the table indicate the advantages of the proposed method for the preparation of a catalyst, which allows to obtain a catalyst with increased activity: the degree of conversion of sulfur dioxide increases from 40 to 41.5-51.0% with

420eC

and from 87 to 88.0–89.2% at 485 ° C, and the mechanical strength increases from 8 to 9.5–12.0 kg / cm, which allows an increase in the service life of the catalyst mash.

Claims (1)

Invention Formula A method of preparing a catalyst for the oxidation of sulfur dioxide containing vanadium pentoxide, a silica carrier, which is a mixture of two components — natural silicon dioxide and silica gel, an alkaline promoter, and sulfuric acid, comprising mixing vanadium pentoxide 1558463 five with an alkaline promoter and one of the components of the silica carrier, adding sulfuric acid to the mixture while maintaining the temperature at 35 ° C, introducing the second component of the silica carrier into the resulting solution, mass forming, subsequent drying and calcination, in order to obtain catalyst with increased activity and mechanical strength, as the first component of the silica carrier use / g of natural silica - diatomite, as the second component - silica sol.