Fluidizable catalysts for oxidative dehydrogenation of hydrocarbons
Fluidizable catalysts for oxygen-free oxidative dehydrogenation of alkanes to corresponding olefins. The catalysts contain 10-20% (by weight per total catalyst weight) of one or more vanadium oxides as the catalytic material, which are mounted upon an alumina support that is modified with zirconia at alumina/zirconia ratios of 5:1 up to 1:2. Various methods of preparing and characterizing the fluidizable catalysts are also provided.
1. A fluidizable catalyst comprising:
a zirconia-modified alumina support material; and
10-20% of one or more vanadium oxides by weight based on a total weight of the fluidizable catalyst, the one or more vanadium oxides being adsorbed onto the support material;
wherein the support material comprises an alumina/zirconia weight ratio of 1-5:1-3; and
wherein the fluidizable catalyst has an average particle size of 40-120 μm.
2. The fluidizable catalyst of claim 1 , wherein the one or more vanadium oxides are selected from the group consisting of V 2 O 5 , VO 2 , and V 2 O 3 .
3. The fluidizable catalyst of claim 2 , comprising at least 50% of V 2 O 5 based on total weight of the one or more vanadium oxides.
4. The fluidizable catalyst of claim 1 , wherein the alumina/zirconia weight ratio is 1-2:1.
5. The fluidizable catalyst of claim 1 , wherein the one or more vanadium oxides form a crystalline phase on the surface of the zirconia-modified alumina support material.
6. The fluidizable catalyst of claim 1 , having an apparent particle density of 1.5-3.5 g/cm 3 .
7. The fluidizable catalyst of claim 1 , having Class B powder properties in accordance with Geldart particle classification.
8. The fluidizable catalyst of claim 1 , wherein the zirconia present in the alumina/zirconia ratio depresses the surface acidity of the fluidizable catalyst.
9. The fluidizable catalyst of claim 1 , wherein the zirconia present in the alumina/zirconia ratio enhances the interaction between the one or more vanadium oxides and the support material.
10. The fluidizable catalyst of claim 1 , wherein the zirconia present in the alumina/zirconia ratio enhances the reducibility of the one or more vanadium oxides.
11. A process for converting an alkane to a corresponding olefin, comprising:
contacting an alkane feed stream with the fluidizable catalyst of claim 1 in an oxygen-free atmosphere at 525-675° C.
12. The process of claim 11 , wherein the alkane is selected from the group consisting of ethane, propane, n-butane and isobutane.
13. The process of claim 11 , wherein the fluidizable catalyst is present at an amount of 0.05-0.5 g/ml of the alkane feed stream.
14. The process of claim 11 , wherein the alkane is ethane and the process has an ethane conversion of 15-45%.
15. The process of claim 11 , wherein the alkane is ethane and the process has an ethylene selectivity of 75-90%.
16. A fluidizable catalyst, comprising:
a zirconia-modified alumina support material; and
10-20% of one or more vanadium oxides by weight based on a total weight of the fluidizable catalyst, the one or more vanadium oxides being adsorbed onto the support material;
wherein the support material comprises an aluminalzirconia weight ratio of 1-5:1-3; and
wherein the fluidizable catalyst is in the form of a plurality of particles and more than 75% of the particles have a particle size of 40-120 μm.
17. A process for converting an alkane to a corresponding olefin, comprising:
contacting an alkane feed stream with the fiuidizable catalyst of claim 16 in an oxygen-free atmosphere at 525-675° C.
18. A fluidizable catalyst, comprising:
a zirconia-modified alumina support material; and
10-20% of one or more vanadium oxides by weight based on a total weight of the fluidizable catalyst, the one or more vanadium oxides being adsorbed onto the support material;
wherein the support material comprises an alumina/zirconia weight ratio of 1-5:1-3; and
wherein the fluidizable catalyst has a BET surface area of 10-50 m 2 /g.
19. A process for converting an alkane to a corresponding olefin, comprising:
contacting an alkane feed stream with the fluidizable catalyst of claim 18 in an oxygen-free atmosphere at 525-675° C.