Catalyst system and process utilizing the catalyst system

Abstract

This invention relates to a catalyst system comprising (a) at least one layer of a first catalyst comprising a dehydrogenation active metal on a solid support; (b) at least one layer of a second catalyst comprising a metal oxide; and (c) at least one layer of a third catalyst comprising a transition metal on an inorganic support; wherein the at least one layer of a second catalyst is sandwiched between the at least one layer of a first catalyst and the at least one layer of a third catalyst; and a process comprising contacting a hydrocarbon feed with the catalyst system.

Claims

1. A catalyst system comprising: (a) at least one layer of a first catalyst comprising a dehydrogenation active metal selected from the group consisting of platinum, palladium, iridium, chromium, and mixtures thereof on a solid support; (b) at least one layer of a second catalyst comprising magnesium oxide, calcium oxide, or a mixture thereof; and (c) at least one layer of a third catalyst comprising a transition metal on an inorganic support; wherein the at least one layer of a second catalyst is sandwiched between the at least one layer of a first catalyst and the at least one layer of a third catalyst.

2. The catalyst system according to claim 1, wherein the solid support is selected from the group consisting of aluminum oxide, silicon dioxide, zirconium dioxide, titanium dioxide, magnesium oxide, calcium oxide, and mixtures thereof.

3. The catalyst system according to claim 1, wherein the first catalyst further comprises an additional active metal selected from the group consisting of potassium, tin, lanthanum, indium, yttrium, ytterbium, rhenium, and mixtures thereof.

4. The catalyst system according to claim 1, wherein the transition metal is selected from the group consisting of molybdenum, rhenium, tungsten, and mixtures thereof.

5. The catalyst system according to claim 1, wherein the inorganic support is selected from the group consisting of aluminum oxide, silicon dioxide, zirconium dioxide, titanium dioxide, zeolite, and mixtures thereof.

6. A process comprising contacting a hydrocarbon feed stream with the catalyst system according to claim 1.

7. The process according to claim 6, wherein the hydrocarbon feed stream is passed through the catalyst system by contacting with the at least one layer of the first catalyst first, the at least one layer of the second catalyst second, and the at least one layer of the third catalyst third.

8. The process according to claim 6, wherein the hydrocarbon feed stream comprises a paraffin selected from the group consisting of ethane, propane, butane, pentane, and mixtures thereof.

9. The process according to claim 6, wherein the process is carried out at a temperature in the range of 200-800° C.

10. The process according to claim 6, wherein the catalyst system is pretreated by contacting the catalyst system with an inert gas, an oxidizing gas, a reducing gas, or mixtures thereof at a temperature in the range of 250-850° C. prior to contacting with the hydrocarbon feed stream.

11. A catalyst system comprising: (a) at least one layer of a first catalyst comprising a dehydrogenation active metal selected from the group consisting of platinum, palladium, iridium, chromium, and mixtures thereof on a solid support; (b) at least one layer of a second catalyst comprising magnesium oxide, calcium oxide, or a mixture thereof; and (c) at least one layer of a third catalyst comprising a transition metal on an inorganic support; wherein the at least one layer of a second catalyst is sandwiched between the at least one layer of a first catalyst and the at least one layer of a third catalyst, and wherein a weight ratio between the at least one layer of a first catalyst to the at least one layer of a third catalyst is in the range of 1:10 to 10:1.

12. The catalyst system of claim 11, wherein the first catalyst further comprises an additional active metal selected from the group consisting of potassium, tin, lanthanum, indium, yttrium, ytterbium, rhenium, and mixtures thereof.

13. The catalyst system of claim 11, wherein the transition metal is selected from the group consisting of molybdenum, rhenium, tungsten, and mixtures thereof.

14. A catalyst system comprising: (a) at least one layer of a first catalyst comprising a dehydrogenation active metal selected from the group consisting of platinum, palladium, iridium, chromium, and mixtures thereof on a solid support; (b) at least one layer of a second catalyst comprising magnesium oxide, calcium oxide, or a mixture thereof; and (c) at least one layer of a third catalyst comprising a transition metal on an inorganic support; wherein the at least one layer of a second catalyst is sandwiched between the at least one layer of a first catalyst and the at least one layer of a third catalyst, and wherein the first catalyst contains 0.01 to 25 wt % of the dehydrogenation active metal.

15. The catalyst system of claim 14, wherein the first catalyst further comprises an additional active metal selected from the group consisting of potassium, tin, lanthanum, indium, yttrium, ytterbium, rhenium, and mixtures thereof.

16. The catalyst system of claim 14, wherein the transition metal is selected from the group consisting of molybdenum, rhenium, tungsten, and mixtures thereof.

17. A catalyst system comprising: (a) at least one layer of a first catalyst comprising a dehydrogenation active metal selected from the group consisting of platinum, palladium, iridium, chromium, and mixtures thereof on a solid support; (b) at least one layer of a second catalyst comprising magnesium oxide, calcium oxide, or a mixture thereof; and (c) at least one layer of a third catalyst comprising a transition metal on an inorganic support; wherein the at least one layer of a second catalyst is sandwiched between the at least one layer of a first catalyst and the at least one layer of a third catalyst, and wherein the third catalyst further comprises a mixed magnesium-aluminum oxide, a mixed calcium-aluminum oxide, or a mixture thereof.

18. The catalyst system of claim 17, wherein the first catalyst further comprises an additional active metal selected from the group consisting of potassium, tin, lanthanum, indium, yttrium, ytterbium, rhenium, and mixtures thereof.

19. The catalyst system of claim 17, wherein the transition metal is selected from the group consisting of molybdenum, rhenium, tungsten, and mixtures thereof.

Description

EXPERIMENTAL RESULTS

Example 1 (Comparative)

(1) Catalyst A was prepared by calcining a Mg—Al—CO3 layered double hydroxide in air at 620° C. for 8 hours to obtain a mixed magnesium-aluminium oxide support, then impregnated a solution of chloroplatinic acid and a solution of indium nitrate hydrate on the support. The obtained mixture was then dried at 110° C. and calcined at 620° C. The resulted Catalyst A contain 0.3 wt % Pt, 0.6 wt % In, on Mg—Al oxide support.

(2) Catalyst B containing 7 wt % W, 4 wt % Y-zeolite, 10 wt % Mg—Al oxide, and balancing SiO2 was prepared by impregnating a solution of ammonium metaungstate hydrate, then dried at 110° C. for 3 hours. Then the resulted material was then mixed with Mg—Al—CO3 layered double hydroxide followed by calcination under air at 550° C. for 2 hours.

(3) 4 grams of the Catalyst was loaded into a ¾ inches stainless steel reactor, followed by 1.5 grams of the Catalyst A. The resulted catalyst bed was pretreated under hydrogen gas at 580° C. for 30 minutes. Then the catalyst bed was left to cool down to 570° C. before propane was fed through the catalyst bed, contacting with the Catalyst A first, at WHSV approximately 0.5 hr.sup.−1.

(4) Effluent from the reactor was sent to a Gas Chromatography equipment to measure product distribution. Result of this test is shown in Table 1.

Example 2

(5) Catalyst A and Catalyst B were prepared using the method described in Example 1.

(6) 4 grams of the Catalyst B was loaded into a ¾ inches stainless steel reactor, followed by 1 gram of calcium oxide, and followed by 1.5 grams of the Catalyst A.

(7) The resulted catalyst bed was subjected to pretreatment and reaction test condition as described in Example 1. Result of this test is shown in Table 1.

Example 3

(8) Catalyst A and Catalyst B were prepared using the method described in Example 1.

(9) 4 grams of the Catalyst B was loaded into a ¾ inches stainless steel reactor, followed by 1 gram of magnesium oxide, and followed by 1.5 grams of the Catalyst A.

(10) The resulted catalyst bed was subjected to pretreatment and reaction test condition as described in Example 1. Result of this test is shown in Table 1.

Example 4

(11) Catalyst C was prepared by calcining a Mg—Al—CO3 layered double hydroxide in air at 620° C. for 8 hours to obtain a mixed magnesium-aluminium oxide support, then impregnated a solution of chloroplatinic acid and a solution of tin chloride hydrate on the support. The obtained mixture was then dried at 110° C. and calcined at 620° C. The resulted Catalyst C contains 0.3 wt % Pt, 0.6 wt % Sn, on Mg—Al oxide support.

(12) Catalyst B was prepared as described in Example 1.

(13) 4 grams of the Catalyst B was loaded into a ¾ inches s less steel reactor, followed by 1 gram of calcium oxide, and followed by 1.5 grams of the Catalyst C.

(14) The resulted catalyst bed was subjected to pretreatment and reaction test condition as described in Example 1. Result of this test is shown in Table 1.

(15) TABLE-US-00001 TABLE 1 C3H8 Selectivity (% wt) Catalyst Conversion Total System (wt %) Olefins CH4 C2H4 C2H6 C3H6 C4H8 C4H10 C5+ Example 1 30.06 84.29 5.05 19.47 8.84 37.21 17.85 1.81 9.64 Example 2 24.01 90.44 4.66 20.65 4.20 42.24 18.17 0.69 9.39 Example 3 31.96 87.14 4.95 20.24 6.85 38.24 17.32 1.05 11.35 Example 4 34.44 88.28 4.58 19.61 6.07 40.29 18.53 1.07 9.85

Example 6 (Comparative)

(16) Catalyst A and Catalyst B were prepared using the method described in Example 1.

(17) 4 grams of the Catalyst B was loaded into a ¾ inches stainless steel reactor, followed by 1.5 grams of the Catalyst A.

(18) The resulted catalyst bed was subjected to pretreatment and reaction test condition as described in Example 1, but at WHSV of approximately 0.2 hr.sup.−1. Result of this test is shown in Table 2.

Example 7

(19) Catalyst A and Catalyst B were prepared using the method described in Example 1.

(20) 0.7 grams of the Catalyst B was loaded into a ¾ inches stainless steel reactor, followed by 1 gram of magnesium oxide, followed by 4 grams of the Catalyst A, followed by 1 gram of magnesium oxide, and followed by 1.5 grams of the Catalyst A.

(21) The resulted catalyst bed was subjected to pretreatment and reaction test condition as described in Example 6. Result of this test is shown in Table 2.

(22) TABLE-US-00002 TABLE 2 C3H8 Selectivity (% wt) Conversion Total Example (% wt) Olefins CH4 C2H4 C2H6 C3H6 C4H8 Example 6 29.9 60.4 11.0 16.6 15.9 30.1 13.7 Example 7 28.3 75.1 3.1 12.8 9.9 43.1 19.2

(23) 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.