Enhanced oxygen transfer agent systems for oxidative dehydrogenation of hydrocarbons
Aspects of the invention relate to enhanced oxygen transfer agent systems and methods of use thereof. According to one aspect, a method for producing olefins from a hydrocarbon feed includes the step of contacting a hydrocarbon feed comprised of one or more alkanes with an oxygen transfer agent at a temperature of 350° C. to 1000° C. The oxygen transfer agent comprising an oxygen-donating chalcogen agent comprised of at least one of S, Se, or Te and a reducible metal oxide. The chalcogen having an oxidation state greater than +2. According to another aspect, a method for producing one or more olefins by partial combustion of a hydrocarbon feed includes partially combusting a hydrocarbon feed comprised of one or more alkanes by contacting the hydrocarbon feed with an oxygen transfer agent comprising CaS0 4 at a temperature of 350° C. to 1000° C. to produce one or more olefins comprising ethylene and coproducing water.
1. A method for producing one or more olefins from a hydrocarbon feed comprised of one or more alkanes, the method comprising:
a step of contacting a hydrocarbon feed comprised of one or more alkanes with an oxygen transfer agent at a temperature of 825° C. to 1000° C., wherein the oxygen transfer agent comprises i) an oxygen-donating chalcogen agent comprising at least one of a sulfate salt of an alkaline earth metal or a sulfate salt of an alkali metal, and a sulfate salt of manganese, and wherein the oxygen-donating chalcogen agent has an oxidation state greater than +2, and ii) a reducible metal oxide, wherein the oxygen-donating chalcogen agent and the reducible metal oxide are in solid form, and wherein water is formed from oxygen donated by the oxygen-donating chalcogen agent.
2. The method of claim 1 , wherein the hydrocarbon feed comprises at least one of methane or ethane, and the produced one or more olefins comprises ethylene.
3. The method of claim 1 , wherein the oxygen transfer agent comprises Mg 6 MnO 8 and at least one promoter selected from the group consisting of Sm, Ga, Ti, W, Mo, V, Nb, Cr, K, Cs, Rb, P, Cu, Pb, Ni and As.
4. The method of claim 3 , wherein the oxygen transfer agent further comprises boron or at least one compound thereof.
5. The method of claim 1 , wherein the oxygen transfer agent additionally comprises at least one alkali metal or a compound thereof.
6. The method of claim 1 , wherein the oxygen transfer agent additionally comprises at least one of an alkali metal oxide or an alkaline earth metal oxide.
7. The method of claim 1 , wherein the oxygen transfer agent comprises a manganese oxide and wherein the manganese has a valence state of 4+, 3+, 8/3+, or 2+.
8. The method of claim 1 , wherein the oxygen transfer agent comprises a) at least one compound selected from the group consisting of NaB 2 Mg 4 Mn 2 O 4 , NaB 2 Mn 2 Mg 4 O 11.5 , NaMn 2 O 4 , LiMn 2 O 4 , Mg 3 Mn 3 B 2 O 10 , Mg 3 (BO 3 ) 2 , and b) a non- crystalline compound comprising oxygen and at least one of sodium, boron, magnesium, manganese, or lithium.
9. The method of claim 1 , wherein the reducible metal oxide is ionically and electronically conductive.
10. The method of claim 1 , wherein at least 49% by moles of the hydrocarbon feed is converted to oxides of carbon, whereby water is produced as a co-product.
11. The method of claim 1 , wherein at least 49% by moles of the hydrocarbon feed is converted to olefins, whereby water is produced as a co-product.
12. The method of claim 1 , wherein the oxygen-donating chalcogen agent comprises calcium sulfate.
13. The method of claim 1 , wherein a chalcogen of the oxygen-donating chalcogen agent has an oxidation state of +3 to +6.
14. The method of claim 13 , wherein the chalcogen of the oxygen-donating chalcogen agent has an oxidation state greater than +3 and less than +6.
15. The method of claim 14 , wherein the chalcogen of the oxygen-donating chalcogen agent has an oxidation state of +4.
16. The method of claim 1 , wherein the oxygen transfer agent further comprises a sulfate salt of Sm, Ga, Ti, W, Mo, V, Nb, Cr, K, Cs, Rb, P, Cu, Pb, Ni, or As.
17. The method of claim 1 , wherein the oxygen transfer agent is in a bed in a reactor and the gas hourly space velocity of the hydrocarbon feed to the bed is at least 600 hr −1 .
18. The method of claim 1 , wherein a yield of ethylene is more than 67% by moles.
19. The method of claim 1 , wherein the contacting takes place in an atmosphere substantially free of molecular oxygen.
20. The method of claim 1 , wherein the contacting takes place in the presence of molecular oxygen.
21. The method of claim 1 , wherein during the contacting step the oxygen transfer agent is converted to a reduced oxygen transfer agent and wherein the method comprises a further step of oxidizing the reduced oxygen transfer agent to regenerate the oxygen transfer agent.
22. The method of claim 1 , wherein the hydrocarbon feed is contacted with the oxygen transfer agent at a temperature of 825° C. to 900° C.
23. The method of claim 1 , further comprising introducing a feed comprising a gaseous compound of sulfur, the gaseous compound of sulfur having an oxidation state of 0 to −2, which acts to stabilize the oxygen transfer agent.