PROCESS FOR REMOVING OXIDISABLE GASEOUS COMPOUNDS FROM A GAS MIXTURE BY MEANS OF A PLATINUM-CONTAINING OXIDATION CATALYST

Abstract

Process for catalytic oxidative removal of at least one oxidisable gaseous compound from a gas mixture comprising the at least one oxidisable gaseous compound as well as oxygen through the use of an oxidation catalyst, whereby the gas mixture is not a combustion flue gas, characterised in that the oxidation catalyst was produced through the use of at least one exothermic-decomposing platinum precursor.

Claims

1. Process for catalytic oxidative removal of at least one oxidisable gaseous compound from a gas mixture comprising the at least one oxidisable gaseous compound as well as oxygen through the use of an oxidation catalyst, whereby the gas mixture is not a combustion flue gas, characterised in that the oxidation catalyst was produced through the use of at least one exothermic-decomposing platinum precursor.

2. Process according to claim 1, whereby the gas mixture is non-explosive.

3. Process according to claim 1, whereby the at least one oxidisable gaseous compound is selected from the group consisting of VOCs, carbon monoxide, and hydrogen.

4. Process according to claim 1, whereby the gas mixture does not contain any halogen-containing organic compounds.

5. Process according to claim 1, whereby the quantitative fraction of the at least one oxidisable gaseous compound contained in the gas mixture is in the range of 10 vol.-ppb to 50,000 vol.-ppm.

6. Process according to claim 1, whereby the quantitative fraction of oxygen contained in the gas mixture is at least adequate, by stoichiometry, for complete oxidation of the at least one oxidisable gaseous compound.

7. Process according to claim 1, whereby the gas mixture contains at least one inert gas selected from the group consisting of nitrogen, noble gases, and. CO.sub.2.

8. Process according to claim 1, whereby the gas mixture is fed into the oxidation catalyst at a temperature in the range of 0 to 600° C.

9. Process according to claim 1, whereby the oxidation catalyst is a fixed-bed catalyst that comprises one or more porous catalyst supports and at least one catalytically active platinum species.

10. Process according to claim 1, whereby the oxidation catalyst is a washcoat-coated or uncoated monolith catalyst, a bulk catalyst comprising washcoat-coated or uncoated bulk form bodies or a washcoat-coated metal honeycomb or metal mesh catalyst.

11. Process according to claim 9, whereby the platinum of the at least one catalytically active platinum species contained in the oxidation catalyst originates, at least in part, from the at least one exothermic-decomposing platinum precursor.

12. Process according to claim 1, whereby the platinum content of the oxidation catalyst is 0.05 to 25 g per litre of catalyst volume.

13. Process according to claim 9, whereby the material of the porous catalyst support(s) comprises or consists of refractory material.

14. Process according to claim 13, whereby the refractory material is selected from the group consisting of aluminium oxides, titanium dioxide, cerium oxides, zirconium oxides, cerium/zirconium mixed oxides, zeolites, aluminium silicates, silicon carbides, silicon nitrides, and any combinations thereof.

15. Process according to claim 1, whereby the at least one exothermic-decomposing platinum precursor was used in the form of a solution for producing the oxidation catalyst.

16. Process according to claim 1, whereby, aside front the at least one exothermic-decomposing platinum precursor, precursors of other metals or noble metals were also used in the production of the oxidation catalyst.

17. Process according to claim 1, aside from the at least one exothermic-decomposing platinum precursor, no precursors of other metals or noble metals were used for producing the oxidation catalyst used in the process according to the invention.

18. Process according to claim 1, whereby, aside from the at least one exothermic-decomposing platinum precursor, no non-exothermic-decomposing platinum precursors where used for producing the oxidation catalyst.

19. Process according to claim 1, whereby the at least one exothermic-decomposing platinum precursor can be exothermically decomposed by heat in the temperature range of 50 to 500° C. or 150 to 200° C.

20. Process according to claim 19, whereby the at least one exothermic-decomposing platinum precursor exclusively shows exothermic behaviour during its decomposition by heat in the temperature range of 50 to 500° C. or 150 to 200° C.

21. Process according to claim 1, whereby the at least one exothermic-decomposing platinum precursor is selected from the group consisting of platinum oxalate complexes and platinum ethanolamine.

Description

EXAMPLES

[0078] The platinum oxalate complexes used in the examples were produced in accordance with WO2014/053351 A1, example 1. The platinum ethanolamine used in the examples is the aforementioned product distributed by HERAEUS .

Example 1

Production of an Oxidation Catalyst

[0079] 30 ml of an aqueous solution of platinum oxalate complexes (500 mg Pt in 30 ml of solution) were mixed with 100 g Al.sub.1O.sub.3 pellets (diameter 2-4 mm) in a rolling flask. The pellets were initially dried at 50° C. The thus impregnated and dried pellets where then calcined at 250° C. in a nitrogen atmosphere in a drying cabinet. Subsequently, this was cooled to room temperature.

Example 2

[0080] An oxidation catalyst was produced analogous to example 1, whereby an aqueous solution of platinum ethanolamine (500 mg Pt in 30 ml of solution) was used instead of the solution of platinum oxalate complexes.

Reference Example 3

[0081] An oxidation catalyst was produced analogous to example 1, whereby an aqueous nitric solution of platinum nitrate (500 mg Pt in 30 ml of solution) was used instead of the solution of platinum oxalate complexes.

Example 4

[0082] The oxidation catalysts produced in examples 1 to 3 were investigated in a catalyst test facility. For this purpose, 70 ml of each of the oxidation catalysts were installed in the reactor. A gas mixture of synthetic air containing 1,000 vol.-ppm methane and 1,000 vol.-ppm propane was guided over the oxidation catalysts at a rate of 10,000 h.sup.−1. The quantitative fractions of methane and propane in the gas mixture were measured by gas chromatography upstream and downstream of the oxidation catalyst, and the turnover was thus determined. For the determination of the light-off temperature (T.sub.50), the gas flow was guided over the oxidation catalyst at 600° C. and the turnover of methane and propane during a subsequent cooling phase was determined. The turnover curves thus obtained or analysed and the temperature T.sub.50, at which the turnover was 50% was determined. The results of the measurements are summarised in the Table below.

TABLE-US-00001 Oxidation catalyst T.sub.50 [° C.] from example Pt precursor for C.sub.3H.sub.8 for CH.sub.4 1 Platinum ethanolamine 239 459 2 Platinum oxalate complexes 232 460 3 (see) Platinum nitrate 282 498