Olefin epoxidation process
View Patent ↗A process for the production of an olefin oxide, which process comprises reacting a feed comprising an olefin and oxygen in a reactor tube in the presence of a silver-containing catalyst, wherein the presence of water in the catalyst bed is controlled such that the ratio of the partial pressure of water (PPH 2 O) divided by the vapor pressure of water (VPH 2 O) is less than 0.006, preferably less than 0.004.
1. A process for the production of ethylene oxide, which process comprises:
(a) contacting a feed comprising ethylene and oxygen in the presence of a silver-containing catalyst to yield a reaction product comprising ethylene oxide, wherein the contacting occurs in a catalyst bed of an epoxidation reactor;
(b) determining a ratio of the partial pressure of water (PPH 2 O) divided by the vapor pressure of water (VPH 2 O) at an axial position (z) in the catalyst bed; and
(c) adjusting one or more epoxidation process conditions so as to reduce the ratio of the partial pressure of water (PPH 2 O) divided by the vapor pressure of water (VPH 2 O) at the axial position (z).
2. The process as claimed in claim 1 , wherein the ratio of the partial pressure of water (PPH 2 O) divided by the vapor pressure of water (VPH 2 O) at the axial position (z) is reduced to less than 0.006.
3. The process as claimed in claim 1 , wherein the ratio of the partial pressure of water (PPH 2 O) divided by the vapor pressure of water (VPH 2 O) at the axial position (z) is reduced to less than 0.004.
4. The process as claimed in claim 1 , which process further comprises:
determining the ratio of the partial pressure of water (PPH 2 O) divided by the vapor pressure of water (VPH 2 O) at a plurality of axial positions in the catalyst bed; and
adjusting one or more epoxidation process conditions so as to reduce the ratio of the partial pressure of water (PPH 2 O) divided by the vapor pressure of water (VPH 2 O) at one or more of the plurality of axial positions in the catalyst bed.
5. The process as claimed in claim 4 , wherein the ratio of the partial pressure of water (PPH 2 O) divided by the vapor pressure of water (VPH 2 O) is less than 0.004 for at least 50 percent of the plurality of axial positions in the catalyst bed.
6. The process as claimed in claim 4 , wherein the ratio of the partial pressure of water (PPH 2 O) divided by the vapor pressure of water (VPH 2 O) is less than 0.004 for at least 80 percent of the plurality of axial positions in the catalyst bed.
7. The process as claimed in claim 4 , wherein adjusting one or more epoxidation process conditions comprises: increasing the cooling of an overhead stream that is supplied to the epoxidation reactor from a CO 2 removal section.
8. The process as claimed in claim 4 , wherein adjusting one or more epoxidation process conditions comprises: increasing the cooling of an overhead stream that is supplied to the epoxidation reactor from an ethylene oxide removal section.
9. The process as claimed in claim 1 , wherein adjusting one or more epoxidation process conditions comprises: increasing the cooling of an overhead stream that is supplied to the epoxidation reactor from a CO 2 removal section.
10. The process as claimed in claim 1 , wherein adjusting one or more epoxidation process conditions comprises: increasing the cooling of an overhead stream that is supplied to the epoxidation reactor from an ethylene oxide removal section.
11. The process as claimed in claim 1 , wherein adjusting one or more epoxidation process conditions comprises: decreasing the amount of a recycle gas that is supplied to a CO 2 absorber section.
12. The process as claimed in claim 1 , wherein adjusting one or more epoxidation process conditions comprises: operating an ethylene oxide absorber and a CO 2 absorber at a lower temperature.
13. The process as claimed in claim 1 , wherein adjusting one or more epoxidation process conditions comprises: increasing the Gas Hourly Space Velocity at a fixed ethylene oxide production.
14. The process as claimed in claim 1 , wherein adjusting one or more epoxidation process conditions comprises: reducing the amount of ethylene oxide produced per unit volume of catalyst.
15. The process as claimed in claim 1 , wherein adjusting one or more epoxidation process conditions comprises: increasing the temperature in the epoxidation reactor.
16. The process as claimed in claim 1 , wherein the silver-containing catalyst comprises rhenium.
17. The process as claimed in claim 1 , wherein the feed further comprises a moderator selected from the group consisting of C 1 to C 8 organic halides.
18. The process as claimed in claim 15 , which process further comprises:
(d) subsequent to (c), increasing the amount of moderator present in the feed.
19. The process as claimed in claim 1 , which process further comprises reacting the ethylene oxide with water to form ethylene glycol.
20. The process of claim 1 , wherein the ratio of the partial pressure of water (PPH 2 O) divided by the vapor pressure of water (VPH 2 O) is less than 0.004 over the entire length of the catalyst bed.