Oxidative dehydrogenation process
The product distribution from an oxidative dehydrogenation process can be altered by co-feeding different ratios of ethanol to steam, in the range of 0.01 to 0.50 ethanol:steam to an oxidative dehydrogenation reactor. Increasing the ethanol to steam ratio was found to: increase ethylene yield; decrease acetic acid yield; increase, or decrease, or cause no effect on CO or CO 2 yield; and have negligible effect on ethane conversion. The feed ethanol is converted to carbonaceous products without negatively effecting the catalyst activity.
1. A process for increasing ethylene yield from an oxidative dehydrogenation (ODH) reactor system, the ODH reactor system comprising an ODH reactor, the ODH reactor containing a bed of mixed metal oxide catalyst, the process comprising:
forming a feed stream comprising ethane and oxygen;
forming an ethanol/steam stream comprising ethanol and steam;
heating the ethanol/steam stream to a temperature above the dew point of ethanol;
co-feeding the heated ethanol/steam stream and the feed stream as a combined feed to the ODH reactor; and
contacting the combined feed with the mixed metal oxide catalyst under ODH conditions to form ethylene;
wherein the combined feed comprises from 0.01 vol. % ethanol to 5.0 vol % ethanol;
wherein the volumetric ratio of ethanol to steam in the combined feed is from 0.01 to 0.50; and
wherein the ethylene yield is increased compared to the same process and oxidative dehydrogenation reactor system wherein the combined stream does not comprise ethanol.
2. The process according to claim 1 , wherein the volumetric ratio of ethanol to steam in the combined feed is in the range of 0.02 to 0.10.
3. The process according to claim 1 , wherein the combined feed comprises from 0.5 vol. % to 2 vol. % ethanol.
4. The process according to claim 1 , wherein the combined feed comprises from 5 vol. % to 20 vol. % oxygen.
5. The process according to claim 1 , wherein the combined feed comprises from 20 vol. % to 50 vol. % ethane.
6. The process according to claim 1 , wherein the ODH reactor system comprises two ODH reactors.
7. The process according to claim 1 , wherein the ODH reactor system comprises two mixed metal oxide catalysts.
8. The process according to claim 1 , wherein the ODH conditions comprise a temperature from 310° C. to 350° C.
9. The process according to claim 1 , wherein the ODH conditions comprise an inlet pressure from 15 psig to 50 psig.
10. The process according to claim 1 , wherein the ODH conditions comprise a residence time from 0.1 to 10 seconds.
11. The process according to claim 1 , wherein the ODH conditions comprise a gas hourly space velocity from 500 to 10,000 h −1 .
12. The process according to claim 1 , wherein the feed stream is outside the flammability envelope.
13. The process according to claim 1 , wherein the ethanol reacts with oxygen to form acetic acid.
14. The process according to claim 1 , wherein the ethanol dehydrates to form ethylene.
15. The process according claim 1 , wherein the process includes having a production rate of acetic acid that is decreased from a process in which only a feed stream is fed to the ODH reactor system.
16. The process according claim 1 , wherein co-feeding the heated ethanol/steam stream with the feed stream to the ODH reactor system yields a production rate of acetic acid that remains the same as a process in which only the feed stream is fed to the ODH reactor system.
17. The process according to claim 1 , wherein the mixed metal oxide catalyst comprises a mixed metal oxide selected from the group according to the formula:
Mo 1 V 0.1-1 Nb 0.1-1 Te 0.01-0.2 X 0-0.2 O f
wherein X is selected from Pd, Sb, Ba, Al, W, Ga, Bi, Sn, Cu, Ti, Fe, Co, Ni, Cr, Zr, Ca and oxides and mixtures thereof, and f is a number to satisfy the valence state of the metals present in the catalyst.
18. The process according to claim 1 , wherein the mixed metal oxide catalyst is diluted with stainless steel, alumina or a combination thereof.
19. A process for the oxidative dehydrogenation (ODH) of ethane into ethylene comprising:
providing a combined feed comprising ethane, oxygen, steam, and ethanol, to an ODH reactor;
contacting the combined feed with an ODH catalyst in the ODH reactor under ODH conditions to form ethylene;
wherein the combined feed comprises from 0.05 vol. % to 5 vol. % ethanol; and
wherein the volumetric ratio of ethanol to steam in the combined feed is between from 0.01 to 0.50.
20. The process of claim 19 wherein ethylene yield is increased compared to a similar process where the combined feed does not contain ethanol.
21. The process according to claim 19 , wherein the combined feed is heated to a temperature above the dew point of ethanol before contacting the ODH catalyst.
22. The process according to claim 19 , wherein the combined feed is outside the flammability limits.
23. The process according to claim 19 , wherein the combined feed comprises from 5 vol. % to 20 vol. % oxygen.
24. The process according to claim 19 , wherein the combined feed comprises from 20 vol. % to 50 vol. % ethane.
25. The process according claim 19 , wherein the combined feed comprises from 0.5 vol. % to 2 vol. % ethanol.
26. The process according to claim 19 , wherein the ODH conditions comprise a temperature of from 300° C. to 400° C.
27. The process according to claim 19 , wherein the ODH conditions comprise an inlet pressure of from 15.0 psig to 50 psig.
28. The process according to any of claims 19 through 25 , wherein the residence of the ODH reactor is from 0.1 seconds to 10 seconds.
29. The process according to claim 19 , wherein the ODH conditions comprise a gas hourly space velocity of from 500 h −1 to 6,000 h −1 .
30. The process according to claim 19 , wherein the ODH conditions comprise a linear velocity of from 10 cm/sec to 200 cm/sec.
31. The process according to claim 19 , wherein the ODH conditions comprise a weight hourly space velocity of 2.0 h −1 to 10 h −1 .
32. The process according to claim 31 , wherein the mixed metal oxide catalyst comprises a mixed metal oxide selected from the group according to the formula:
Mo 1 V 0.1-1 Nb 0.1-1 Te 0.01-0.2 X 0-0.2 O f
wherein X is selected from Pd, Sb, Ba, Al, W, Ga, Bi, Sn, Cu, Ti, Fe, Co, Ni, Cr, Zr, Ca and oxides and mixtures thereof, and f is a number to satisfy the valence state of the metals present in the catalyst.