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 said catalyst has the structure obtained when the carrier is first calcined at a temperature higher than 700° C. prior to impregnation with a solution comprising iron and molybdenum precursors.
2. A catalyst according to claim 1 , wherein the iron is in the form of iron sulphide.
3. A catalyst according to claim 1 , wherein the molybdenum is in the form of molybdenum sulphide.
4. A catalyst according to claim 1 , wherein the aluminum is in the form of Al 2 O 3 .
5. A catalyst according to claim 1 , wherein the iron is present in the catalyst in a range of from 1 to 50% by weight.
6. A catalyst according to claim 1 , wherein the molybdenum is present in the catalyst in a range of from 1 to 50% by weight.
7. 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 claim 1 .
8. A method according to claim 7 , wherein the catalytic oxidative cracking is conducted with a molar ratio H 2 S/O 2 in the feedstock higher than 2:1.
9. A method according to claim 8 , wherein the ratio is 3:1-5:1.
10. A method according to claim 7 , wherein the catalytic oxidative cracking is conducted using an oxygen-containing gas-stream comprising at least 40 vol. % oxygen.
11. A method according to claim 10 , wherein the oxygen-containing gas-stream is oxygen having a purity of from 90-100 vol. %.
12. A method according to claim 7 , wherein the catalytic oxidative cracking is conducted substantially autothermally at a temperature of from 900° C. to 1500° C.
13. A method according to claim 7 , comprising a further step of subjecting formed SO 2 to hydrogenation.
14. A method according to claim 7 , wherein gas produced from the catalytic oxidative cracking is, substantially without delay, quenched to a temperature below 950° C.
15. A method according to claim 7 , 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 the Catalytic Oxidative Cracking reaction zone or zones.
16. A method according to claim 7 , wherein the Catalytic Oxidative Cracking stage is followed by a Claus catalytic stage, comprising a gas reheater, Claus catalytic reactor and sulphur condenser.
17. A method of making a catalyst according to claim 1 , 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 aluminum;
wherein the carrier is calcined at a temperature higher than 700° C. prior to dispersing of the solution onto the carrier.
18. A method according to claim 8 , 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.
19. A catalyst according to claim 4 , wherein the carrier is made up of Al 2 O 3 .
20. A catalyst according to claim 5 , wherein the carrier is made up of Al 2 O 3 .
21. A catalyst according to claim 6 , wherein the carrier is made up of Al 2 O 3 .
22. A method according to claim 9 , wherein the ratio is 4:1-4.5:1.
23. A method according to claim 10 , wherein the catalytic oxidative cracking is conducted using an oxygen-containing gas-stream comprising at least 60 vol. % oxygen.
24. A method according to claim 12 , wherein the catalytic oxidative cracking is conducted substantially autothermally at a temperature of from 900° C.-1200° C.
25. A method according to claim 12 , wherein the catalytic oxidative cracking is conducted substantially autothermally at a temperature of about 1100° C.