Catalyst for a sulphur recovery process with concurrent hydrogen production, method of making thereof and the sulphur recovery process with concurrent hydrogen production using the catalyst
Disclosed is a catalyst suitable for the catalytic oxidative cracking of a H 2 S-containing gas stream, particularly in the event that the stream also contains methane and/or ammonia. The catalyst comprises iron and molybdenum supported by a carrier comprising aluminum. The carrier preferably is alumina. The iron and molybdenum preferably are in the form of sulphides. Also disclosed is a method for the production of hydrogen from a H 2 S-containing gas stream, comprising subjecting the gas stream to catalytic oxidative cracking so as to form H 2 and S 2 , using a catalyst in accordance with any one of the preceding claims.
1. A catalyst suitable for the catalytic oxidative cracking of a H 2 S-containing gas stream, the catalyst comprising iron and molybdenum supported by a carrier comprising aluminium, wherein the iron is in the form of iron sulfide, wherein the molybdenum is in the form of molybdenum sulfide, wherein the carrier is made up of Al 2 O 3 , wherein the iron is present in the catalyst at 2% by weight of the catalyst and wherein the molybdenum is present in the catalyst at 6% by weight of the catalyst.
2. A method for the production of hydrogen from a H 2 S-containing gas stream, comprising subjecting the gas stream to catalytic oxidative cracking so as to form H 2 and S 2 , using a catalyst comprising iron and molybdenum supported by a carrier comprising aluminium, wherein the H 2 S-containing gas stream and an oxygen-containing gas stream are mixed prior to contacting said catalyst in a reaction chamber and the catalytic oxidative cracking is conducted at 900°-1500° C.
3. A method according to claim 2 , wherein the catalytic oxidative cracking is conducted with a molar ratio H 2 S/O 2 in the feedstock higher than 2:1.
4. A method according to claim 3 , wherein the ratio is 3:1-5:1.
5. A method according to claim 2 , wherein the oxygen-containing gas-stream comprises at least 40 vol. % oxygen.
6. A method according to claim 5 , wherein the oxygen-containing gas-stream is oxygen having a purity of from 90-100 vol. %.
7. A method according to claim 2 , wherein the catalytic oxidative cracking is conducted in the reaction chamber substantially autothermally at a temperature of from 900° C. to 1500° C.
8. A method according to claim 2 , comprising a further step of subjecting formed SO 2 to hydrogenation.
9. A method according to claim 2 , wherein effluent from the reaction chamber containing gas produced from the catalytic oxidative cracking is, substantially without delay, quenched to a temperature below 950° C.
10. A method according to claim 2 , wherein the H 2 S-containing acid gas and the oxygen-containing gas are mixed in a static mixer before entering a first catalytic bed in a catalytic oxidative cracking reaction zone or zones in said reaction chamber.
11. A method according to claim 2 , wherein the catalytic oxidative cracking stage is followed by a Claus catalytic stage, comprising a gas reheater, Claus catalytic reactor and sulphur condenser.
12. A method of making the catalyst of claim 1 , the method comprising providing an aqueous solution of precursors for iron and molybdenum, selected from the group consisting of iron tetracarbonyl, iron pentacarbonyl, iron nonacarbonyl, iron nitrates, iron bromides, iron chlorides, iron fluorides, iron phosphates, iron sulphates, iron acetylacetonates, iron acetates, iron fumarates, iron gluconates, iron citrates, iron benzoates, iron maleates, iron oxalates, iron oleates, and iron stearates, iron-ammonium complexes, and the analogous molybdenum precursors, and dispersing the solution onto a carrier comprising aluminium.
13. The method according to claim 12 , wherein the carrier is calcined at a temperature higher than 700° C. prior to dispersing of the solution onto the carrier.
14. A method according to claim 3 , wherein the catalytic oxidative cracking is conducted with a molar ratio H 2 S/O 2 in the feedstock in the range of 2:1-6:1.
15. A method according to claim 4 , wherein the ratio is 4:1-4.5:1.
16. A method according to claim 5 , wherein the catalytic oxidative cracking is conducted using an oxygen-containing gas-stream comprising at least 60 vol. % oxygen.
17. A method according to claim 7 , wherein the catalytic oxidative cracking is conducted substantially autothermally at a temperature of from 900° C.-1200° C.
18. A method according to claim 17 , wherein the catalytic oxidative cracking is conducted substantially autothermally at a temperature of from 1100° C.
19. The method of claim 2 wherein the H 2 S-containing gas stream further contains ammonia.
20. The method of claim 19 wherein the oxygen-containing gas stream comprises extra oxygen for reaction with said ammonia to provide a molar ratio H 2 S/O 2 between 0.9 and 1.5.