SU1219134A1 - Catalyst for gas-phase oxidation of hydrogen sulphide to sulphur - Google Patents

Abstract

The catalyst contains components at the following ratio: ferrous oxide 20-75 and chromic oxide 25-80 in % by mass. The catalyst may comprise oxides of cobalt, nickel, manganese, copper, zinc and titanium in an amount of 1,5 to 25 % by mass.

Description

This invention relates to catalysts for the oxidation of hydrogen sulphide from gases and may be used in the processes for the purification of hydrogen sulphide from natural gases, refinery gases, Tadjer tail gases from the Claus process.

Known catalyst. For gas-phase oxidation of hydrogen sulfide containing oxides of titanium and iron with the following content of components, wt.%: Iron oxide 0.05-0.3, diox. titanium sit - the rest.

A catalyst containing 0.1 wt.% Iron oxide and 99.9 wt.% Titanium dioxide is the most effective and provides a maximum hydrogen sulfide conversion of 99.5% and a selectivity of 100% when processing large amounts of hydrogen sulfide up to 25%. However, a high activity of a catalyst of such a composition can be achieved only by two-stage oxidation of hydrogen sulfide with a separate supply of oxygen to each stage and the trapping of the sulfur and water formed at the intermediate stage. The performance of the titanium-iron oxide catalyst is low, since it exhibits a high lisch activity at low volumetric feed rates of not more than 3000 hours, an increase in the space velocity to 15,000 leads to a significant decrease in catalyst activity. At the same time, efficient operation of the catalyst is possible only at elevated temperatures of 285-300 ° C.

Closest to the proposed technical essence and the achieved effect is a catalyst for cleaning gases containing sulfur compounds, for example hydrogen sulfide, carbon disulfide, mercaptan, sulfur dioxide, by oxidizing them, containing a carrier — titanium dioxide or zirconium, or silicon , or a zeolite and one or more oxides of the following metals: Cu, Ag, Zn, Cd, V, Za Cr, Mo, W, Fe, Co, Ni, Rh, Jr, Pd, Pt, Sn, Bi, with the total -, the content of one or several metals on the support is 0.005%: 25% by weight.

However, a known catalyst is characterized by insufficient activity. Thus, in the oxidation of hydrogen sulfide at 240 s and V 6000 h in

five

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5 0 5 o

.Q.,

five

five

342.

the presence of a catalyst containing oxides of iron, chromium, zinc and titanium dioxide in the following ratio, wt.%: 8, 9, ZnO 8, TiOj 75, the degree of conversion of hydrogen sulfide is 81.5%, the selectivity is 82.5%.

The aim of the invention is to increase the activity of the catalyst.

The goal is achieved by the fact that the catalyst for gas-phase oxidation of hydrogen sulfide, sulfur, including oxides of iron, chromium, zinc and titanium dioxide, contains these components in the following ratio, wt%:

Iron oxide 20-30 Chromium oxide 20-50

Zinc Oxide 20-25

Titanium dioxide 10-30 The proposed catalyst has a higher activity than the known one. So with the oxidation of hydrogen sulfide at 240 ° C and V 6000 hours in the presence of the proposed catalyst for the conversion of hydrogen sulfide and the selectivity reaches 100%.

The catalyst is prepared by separate precipitation of hydroxides from aqueous solution of titanium, iron, zinc and chromium chlorides 3 n. ammonia water solution. The resulting solutions of hydroxides are drained and the mixture is washed with distilled water, then the catalyst is filtered, molded, dried and calcined at 500 ° C for 4 hours.

Example 1. The catalyst is 1% by weight:, 25, Ti02 25, Cr-jOg 25, Zn 0-25.

To prepare the catalyst, 25.5 g of ferric chloride are dissolved in separate containers in 943 ml of distilled water, 26.3 g of chromium chloride in 1000 ml of water, and 12.5 g of zinc chloride in 916 ml of water and 17.8 g of chloride titanium - in 940 ml of water. To the resulting solution is poured 3 n. aqueous ammonia solution until complete precipitation of hydroxides of iron, chromium, zinc and titanium. Hydroxides are poured into a common container, mixed thoroughly, and the mixture is washed with distilled water until a negative reaction to chlorine ions. Next, the catalyst is filtered off, molded, dried in air at room temperature and calcined at 500 ° C for 4 hours.

3

the result is a catalyst of the composition.

Example 2. The catalyst composition, masl: FejOj 30, TiO 30, 20, ZnO 20.

To prepare the catalyst, 30.5 g of ferric chloride are dissolved in 1128 ml of distilled water} 21 g of chromium chloride in 788 ml of water. South of zinc chloride - in 734 ml of water; 21.5 g of titanium chloride - in 1133 ml of water. To the resulting solution is poured 3 n. ammonia water until complete precipitation of hydroxides. Then the hydroxides are drained, thoroughly mixed, and the mixture is washed with distilled water until a negative reaction to chlorine ions. Then the catalyst is filtered off, molded dried in air at room temperature and calcined for 4 hours at 50 ° C.

As a result of preparation, a catalyst of the specified composition is obtained.

Example 3. The catalyst composition, wt.%:, 20, TiOg 10, 50, ZnO 20.

For the preparation of the catalyst, 20.3 g of ferric chloride in 750 ml of WATER is dissolved} 7.1 g of titanium chloride in 375 ml of water; 52.6 g of chromium chloride - in 1975 ml of labor and 10 g of zinc chloride - in 735 ml of water. From the obtained solutions 3 n. an aqueous solution of ammonia precipitated corresponding

1 TiO 25i Fe, 0, 25; 220

2 Oe

Cr, jO, 25; ZnO 25 240

260

TiO 30; Fe, jO, 3d, 220

CrjO, 20; ZnO 20 240

TiOj 10} Fe 0 20; 220

 50; ZnO 20 240

191344

hydroxides. Solutions of hydroxides are mixed and the precipitate is washed with distilled water. Next, the precipitate is filtered off, the catalyst is molded, dried at room temperature and calcined for 4 hours at.

Studies of the activity of the prepared catalysts are carried out at 220-260 ° C, volume rates of 3000-10-15000 h and ratios of Og 1-1.5. The research results are summarized in table. 1, which compares the data and the results of the process on a known catalyst. In tab. 2 shows the composition data

15

the proposed catalyst and known.

As can be seen from the table. 2, on one of the samples having a composition outside the indicated limits, both the high conversion of hydrogen sulfide and the selectivity of its oxidation to elemental sulfur are not achieved at the same time.

The proposed catalyst has a high activity, it allows to increase productivity in a wide range of volumetric rates and low temperatures in sulfur production processes when cleaning hydrogen sulfide-containing gases, as well as when deactivating air in chemical industry.

g T a b l and c a 1

3 3 3

3 3

3 3

3 4.5

3

4.5

100 99.1

98.5 98.6

100 100

100 100

Editor L, Gratilllo

Sostaivtel V.Tepl kova

Tehred A. Komarnidka Proofreader E. Sirohman

Order 1184/10 Circulation 527 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

ShSh Patent Branch, .g. Uzhgorod, st. Project, 4

Continuation of table 1

table 2

Claims (1)

CATALYST FOR GAS-PHASE OXIDATION OF HYDROGEN SULPHIDE IN SULFUR, including oxides of iron, chromium, zinc and titanium dioxide, characterized in that, in order to increase the activity of the catalyst, it contains the indicated codicomponents in the following ratio, wt.%: Iron Oxide 20-30 Chromium oxide .20-50 Zinc Oxide 20-25 Titanium dioxide 10-30