Attrition resistant, zinc titanate-containing, reduced sulfur sorbents and methods of use thereof
View Patent ↗Reduced sulfur gas species (e.g., H 2 S, COS and CS 2 ) are removed from a gas stream by compositions wherein a zinc titanate ingredient is associated with a metal oxide-aluminate phase material in the same particle species. Nonlimiting examples of metal oxides comprising the compositions include magnesium oxide, zinc oxide, calcium oxide, nickel oxide, etc.
1. A process for removing a reduced sulfur gas from a process stream, said process comprising contacting the process stream with a reduced sulfur gas sorbing composition comprising, in the same particle, zinc titanate and a metal oxide-aluminate phase in order to remove at least a portion of the reduced sulfur gas from the process stream, said particle being substantially free of unreacted alumina.
2. The process according to claim 1 , wherein the metal oxide-aluminate phase of the sulfur sorbing composition has the general formula MO-aluminate, wherein M is a metal selected from the group consisting of magnesium, zinc, nickel and calcium, and O is oxygen.
3. The process according to claim 1 , wherein the metal oxide-aluminate phase is zinc oxide-aluminate.
4. The process according to claim 1 , wherein the metal oxide-aluminate phase is calcium oxide-aluminate.
5. The process according to claim 1 , wherein the metal oxide-aluminate phase is magnesium oxide-aluminate.
6. The process according to claim 1 , wherein the reduced sulfur gas sorbing composition, after sorption of a reduced sulfur gas, is contacted with an oxygen-containing gas at an elevated temperature in order to desorb a reduced sulfur gas and thereby regenerate the reduced sulfur gas sorbing composition for subsequent reduced sulfur gas sorption duty.
7. The process according to claim 1 , wherein the composition further comprises a binder material.
8. The process according to claim 1 , wherein the composition is in the form of microspheroidal particles.
9. The process according to claim 1 , wherein the composition is constantly recirculated in a fluid bed reactor to effect sorption of the reduced sulfur gas.
10. The process according to claim 1 , further comprising regeneration of the composition by extracting a portion of partially sorbed particles and subjecting said particles to regeneration.
11. The process according to claim 1 , further comprising regeneration of the composition by ceasing a gas flow in said process and then subjecting the sorbent to a regeneration process.
12. The process according to claim 1 , wherein a reduced sulfur gas is removed from a coal gas stream.
13. The process according to claim 1 , wherein a reduced sulfur gas is removed from a hydrocarbon gas stream.
14. A process for removing a reduced sulfur species from a process stream, comprising:
(a) providing an attrition-resistant particulate sorbent comprising a plurality of substantially uniform particles comprising a zinc titanate phase and a zinc oxide-aluminate phase, said zinc titanate phase being present in an amount of from about 5 w. % to about 80 w. % of said particles, said zinc oxide-aluminate phase being present in an amount of from about 20 w. % to about 95 w. % of said particles, said zinc titanate and zinc oxide-aluminate phases constituting at least about 80 w. % of said particles, and said particles being substantially free of unreacted alumina; and
(b) contacting the process stream with said particulate sorbent under conditions sufficient to cause sorption of sulfur by said particulate sorbent.
15. The process according to claim 14 , further comprising: contacting the particulate sorbent with an oxygen-containing gas at an elevated temperature after sorption of sulfur to remove sulfur, thereby regenerating the particulate sorbent for subsequent sorption duty.
16. The process according to claim 15 , wherein the steps of contacting the process stream with said particulate sorbent and contacting the particulate sorbent with the oxygen-containing gas are each conducted in a fluid bed reactor.
17. The process according to claim 16 , wherein the particulate sorbent is recirculated from the step of contacting the particulate sorbent with the oxygen-containing gas to the step of contacting the process stream with said particulate sorbent.
18. The process according to any one of claims 14 , 16 or 17 , wherein said process stream is a coal gas stream.
19. The process according to any one of claims 14 , 16 or 17 , wherein said process stream is a hydrocarbon gas stream.