Hydrocarbon conversion process

Abstract

The present invention relates to a hydrocarbon conversion process comprising contacting a hydrocarbon feed stream with a hydrocarbon conversion catalyst, wherein the hydrocarbon conversion catalyst comprises a first composition comprising a dehydrogenation active metal on a solid support; and a second composition comprising a transition metal and a doping agent on an inorganic support, wherein the doping agent is selected from zinc, gallium, indium, lanthanum, and mixtures thereof.

Claims

1. A hydrocarbon conversion process comprising dehydrogenation and metathesis of a hydrocarbon feed stream, said process comprising contacting the hydrocarbon feed stream with a hydrocarbon conversion catalyst, wherein the hydrocarbon conversion catalyst comprises: a first composition comprising a dehydrogenation active metal on a solid support, said solid support comprising aluminum oxide, silicon dioxide, zirconium dioxide, titanium dioxide magnesium oxide, calcium oxide, or a mixture of two or more thereof; and a second composition comprising from 1 wt-% to 15 wt-% tungsten and a doping agent on an inorganic support, wherein the doping agent is selected from zinc, gallium, indium, lanthanum, and mixtures thereof, wherein the solid support of the first composition is different from the inorganic support of the second composition, and wherein the inorganic support of the second composition comprises silicon dioxide and further comprises a mixed magnesium-aluminum oxide or a mixed calcium-aluminum oxide.

2. The hydrocarbon conversion process according to claim 1, wherein the dehydrogenation active metal is selected from platinum, palladium, iridium, chromium, and mixtures thereof.

3. The hydrocarbon conversion process according to claim 1, wherein the inorganic support further comprises aluminum oxide, zirconium dioxide, titanium dioxide, zeolite, and mixtures thereof.

4. The hydrocarbon conversion process according to claim 1, wherein the tungsten of the second composition is in the form of tungsten oxide and the inorganic support comprises said silicon dioxide and said mixed magnesium-aluminum oxide, in a physical mixture with Y-zeolite.

5. The hydrocarbon conversion process according to claim 1, wherein the second composition contains 0.1 to 10 wt % of the doping agent based on the total weight of the second composition.

6. The hydrocarbon conversion process according to claim 1, wherein the first composition and the second composition are physically mixed.

7. The hydrocarbon conversion process according to claim 1, wherein the hydrocarbon feed stream comprises a paraffin selected from ethane, propane, butane, pentane, and mixtures thereof.

8. The hydrocarbon conversion process according to claim 1, wherein the hydrocarbon conversion process is carried out at a temperature in a range of 200−800° C.

9. The hydrocarbon conversion process according to claim 1, wherein the hydrocarbon conversion process is performed in a fixed bed of said hydrogen conversion catalyst.

10. The hydrocarbon conversion process according to claim 1, wherein the hydrocarbon conversion catalyst is pretreated by contacting the hydrocarbon conversion catalyst with an inert gas, an oxidizing gas, a reducing gas, or mixtures thereof, at a temperature in a range of 250° C. to 850° C. prior to contacting the hydrocarbon feed stream with the hydrocarbon conversion catalyst.

11. The hydrocarbon conversion process according to claim 1, wherein the hydrocarbon conversion process further comprises a regeneration step carried out by contacting a spent hydrocarbon conversion catalyst with an oxidizing gas at a temperature in a range of 200−700° C.

12. The hydrocarbon conversion process of claim 1, wherein the solid support of the first composition comprises a mixture of silicon dioxide and zirconium dioxide, and the inorganic support of the second composition further comprises Y-zeolite.

13. The hydrocarbon conversion process of claim 1, wherein the solid support of the first composition further comprises a mixed magnesium-aluminum oxide, and the inorganic support of the second composition further comprises Y-zeolite.

14. The hydrocarbon conversion process of claim 1, wherein the first composition and the second composition are present together in a single form as a physical mixture, wherein the single form is selected from an extrudate, a sphere, a pellet, and a tablet.

15. The hydrocarbon conversion process of claim 14, wherein the physical mixture comprises a powder of the first composition and a powder of the second composition.

16. The hydrocarbon conversion process of claim 1, wherein the hydrocarbon feed stream comprises propane and the hydrocarbon conversion process produces a product comprising ethylene and butene resulting from the conversion of propane, and further wherein a selectivity to total olefins, including the ethylene and butene, is at least about 80% by weight.

17. The hydrocarbon conversion process of claim 1, wherein the second composition comprises from 5 wt-% to 10 wt-% of said tungsten.

18. The hydrocarbon conversion process of claim 6, wherein the first composition and the second composition are physically mixed in weight ratio of 1:10 to 10:1.

19. The hydrocarbon conversion process of claim 18, wherein the first composition and the second composition are physically mixed in a weight ratio of 1:5 to 5:1.

Description

EXPERIMENTAL RESULTS

(1) In the examples section below, the conversion of propane into olefins, preferably ethylene and butene, has been investigated using a hydrocarbon conversion catalyst according to the present invention and a comparative catalyst.

Example 1 Comparative

(2) A solution of chloroplatinic acid hexahydrate and a solution of ytterbium trinitrate are co-impreganted onto powder of silica-zirconia mixture, then the resulting material was dried at 100° C. for 2 hours, followed by calcination under air at 700° C. for 3 hours to obtain a first composition containing 1 wt % Pt and 0.15 wt % Yb and balancing SiO.sub.2—ZrO.sub.2, wherein the weight percentages based on the total weight of the first composition.

(3) A support for a second composition was prepared by mixing SiO.sub.2 with HY-Zeolite. The SiO.sub.2-Zeolite support was then impregnated using a solution of ammonium metatungstate hydrate, then dried at 110° C. for 3 hours. The resulted material was then mixed with Mg—Al—CO3 layered double hydroxide followed by calcination under air at 550° C. for 2 hours to obtain a second composition containing 7 wt % W, 4 wt % Y-zeolite, 9 wt % Mg—Al oxide, and balancing SiO2, wherein the weight percentages are based on the total weight of the second composition.

(4) The first composition and the second composition were physically mixed 1:1 by weight to obtain Example 1 catalyst.

Example 2

(5) A first composition is prepared the s y as described in Example 1.

(6) A support for a second composition was prepared by mixing SiO.sub.2 with HY-Zeolite. The SiO.sub.2-Zeolite support was then impregnated using a solution of ammonium metatungstate hydrate, then dried at 110° C. for 3 hours. The dried mixture was then impregnated using a solution of zinc nitrate hexahydrate, then left to dry once again at 110° C. for 3 hours. The resulted material was then mixed with Mg—Al—CO3 layered double hydroxide followed by calcination under air at 550° C. for 2 hours to obtain a second composition containing 7 wt % W, 4 wt % Zn, 4 wt % Y-zeolite, 9 wt % Mg—Al oxide, and balancing SiO2, wherein the weight percentages are based on the total weight of the second composition.

(7) The first composition and the second composition were physically mixed 1:1 by weight to obtain Example 2 catalyst.

Example 3

(8) A first composition is prepared the same way as described in Example 1.

(9) A support for a second composition was prepared by mixing SiO.sub.2 with HY-Zeolite. The SiO.sub.2-Zeolite support was then impregnated using a solution of ammonium metatungstate hydrate, then dried at 110° C. for 3 hours. The dried mixture was then impregnated using a solution of indium trinitrate, then left to dry once again at 110° C. for 3 hours. The resulted material was then mixed with Mg—Al—CO3 layered double hydroxide followed by calcination under air at 550° C. for 2 hours to obtain a second composition containing 7 wt % W, 2 wt % In, 4 wt % Y-zeolite, 9 wt % Mg—Al oxide, and balancing SiO2, wherein the weight percentages are based on the total weight of the second composition.

(10) The first composition and the second composition were physically mixed 1:1 by weight to obtain Example 3 catalyst.

Example 4

(11) A first composition is prepared the same way as described in Example 1.

(12) A support for a second composition was prepared by g SiO.sub.2 with HY-Zeolite. The SiO.sub.2-Zeolite support was then impregnated using a solution of ammonium metatungstate hydrate, then dried at 110° C. for 3 hours. The dried mixture was then impregnated using a solution of lanthanum (III) nitrate hexahydrate, then left to once again at 110° C. for 3 hours. The resulted material was then mixed with Mg—Al—CO3 layered double hydroxide followed by calcination under at 550° C. for 2 hours to obtain a second composition containing 7 wt % W, 2 wt % La, 4 wt % Y-zeolite, 9 wt % Mg—Al oxide, and balancing SiO2, wherein the weight percentages are based on the total weight of the second composition.

(13) The first composition and the second composition were physically mixed 1:1 by weight to obtain Example 4 catalyst.

(14) Each catalyst as prepared above was packed in a q tube micro reactor and pretreated with hydrogen at approximately 600° C. for half an hour before contacted with propane at approximately 500° C., 0.05-0.1 bar gauge, and WHSV of approximately 0.1-0.2 hr-.sup.−1. The results measured at time on stream for approximately 60 hours and 100 hours are shown in the Table 1 below.

(15) TABLE-US-00001 TABLE 1 Result Selectivity (% wt) C3H8 Conversion (% wt) Total Olefins CH4 C2H4 C3H6 C4H8 60 h 100 h 60 h 100 h 60 h 100 h 60 h 100 h 60 h 100 h 60 h 100 h Example 1 19.64  7.25 74.42  83.78  8.44  5.47  2.60  6.58  59.04  60.76  12.78  16.44  Example 2 15.994  7.510 85.703 92.367 2.688 1.838 3.394 8.298 71.330 70.128 10.978 13.941 Example 3 17.006 11.950 87.079 91.335 1.714 1.183 3.001 5.663 72.442 71.039 11.635 14.632 Example 4 17.227 10.957 80.998 89.495 5.855 3.949 2.826 4.285 65.955 73.758 12.216 11.451

(16) As be seen from the above table, for the inventive hydrocarbon conversion process, the total olefins selectivity is significantly increased, while methane production is decreased. The high total olefins selectivity also shows that (re)hydrogenation of olefins obtained is low.

(17) The features disclosed in the foregoing description and the claims may, both separately and in any combination thereof, be material for realizing the invention in diverse forms thereof.