Catalyst system for dewaxing

Abstract

A catalyst system for dewaxing of a hydrocarbon feedstock comprising at least two catalytic sections, the first section comprising a first dewaxing catalyst and a subsequent section comprising a second dewaxing catalyst, wherein the first dewaxing catalyst is a ZSM-12 zeolite based catalyst and the second dewaxing catalyst is a EU-2 and/or ZSM-48 zeolite based catalyst. The catalyst system displays enhanced performance when compared to systems containing either ony ZSM-12 based catalyst or EU-2/ZSM-48 based catalyst only.

Claims

1. A process for dewaxing a hydrocarbon feedstock, wherein the process comprises: passing the hydrocarbon feedstock to a stacked catalyst system that comprises at least two separate catalytic zones, including a first separate zone, containing a first volume of a first dewaxing catalyst, and a second volume of a second separate zone, containing a second dewaxing catalyst, wherein the stacked catalyst system has a catalyst volume ratio of the first volume-to-second volume in the range of from 10:90 to 90:10; wherein the first dewaxing catalyst comprises ZSM-12 having a silica-to-alumina ratio of at least 50:1 to at most 250:1 and in an amount of at least 10 wt. % and at most 70 wt. %, a binder in an amount of at least 30 wt. % and no more than 90 wt. %, and from 0.1 wt. % to about 3 wt. % of a noble metal component selected from the group consisting of palladium and platinum, with such wt. % being based on the dry weight of the first dewaxing catalyst, and wherein the second dewaxing catalyst comprises EU-2 and/or ZSM-48 having a silica-to-alumina ration of at least 60:1 to at most 300:1 and in an amount of at least 15 wt. % and at most 70 wt. %, a binder in an amount of at least 30 wt. % and no more than 85 wt. %, and from 0.1 wt. % to about 3 wt. % of a noble metal component selected from the group consisting of palladium and platinum, with such wt. % being based on the dry weight of the composition; and wherein the hydrocarbon feedstock first passes to the first dewaxing catalyst followed by passing it to the second dewaxing catalyst, wherein the hydrocarbon feedstock is contacted with the stacked catalyst system at a temperature from 200° C. up to 450° C. and a pressure of from 5 to 200×10.sup.5 Pa.

2. The process of claim 1, wherein the first dewaxing catalyst further comprises from 0.2 wt. % to 2 wt. % of a noble metal component selected from the group consisting of palladium and platinum, and the second dewaxing catalyst further comprises from 0.2 wt. % to 2 wt. % of a noble metal component selected from the group consisting of palladium and platinum.

3. The process of claim 1, wherein the ZSM-12 zeolite has a silica to alumina molar ratio of greater than 60:1 and at most 200:1.

4. The process of claim 1, wherein the EU-2 and/or ZSM-48 zeolite has a silica to alumina molar ratio of at least 70:1 and at most 250:1.

5. The process of claim 1, wherein the catalyst volume ratio of the first dewaxing catalyst to the second dewaxing catalyst is in the range of 20:80 to 90:10.

6. The process according to claim 1, in which process the hydrocarbon feedstock is a wax-containing feed that boils in the lubricating oil range having a 10% distillation point at 200° C. or higher, as measured by ASTM D-2887-93.

7. A process for dewaxing a hydrocarbon feedstock, wherein the process comprises: providing one or more reactors, wherein each is loaded with a stacked catalyst system, comprising at least two separate catalytic zones, including a first separate zone, containing a first volume of a first dewaxing catalyst, and a second separate zone, containing a second dewaxing catalyst, wherein the first dewaxing catalyst is a second volume of a ZSM-12 zeolite based catalyst and the second dewaxing catalyst is a EU-2 and/or ZSM-48 zeolite based catalyst, wherein the stacked catalyst system has a catalyst volume ration of the first volume-to-the second volume in the range of from 10:90 to 90:10; and passing a hydrocarbon feed over the first dewaxing catalyst followed by the second dewaxing catalyst; wherein the first dewaxing catalyst comprises ZSM-12, having a silica-to-alumina ratio of at least 50:1 to at most 250:1, and in an amount of at least 15 wt. % and at most 70 wt. %, a binder in an amount of at least 30 wt. % and no more than 90 wt. %, and from 0.1 wt. % to about 3 wt. % of a noble metal component selected from the group consisting of palladium and platinum, with such wt. % being based on the dry weight of the first dewaxing catalyst; and wherein the second dewaxing catalyst comprises EU-2 and/or ZSM-48, having a silica-to-alumina ratio of at least 60:1 and at most 300:1, and in an amount of at least 15 wt. % and at most 70 wt. %, a binder in an amount of at least 30 wt. % and no more than 85 wt. %, and from 0.1 wt. % to about 3 wt. % of a noble metal component selected from the group consisting of palladium and platinum, with such wt. % being based on the dry weight of the second dewaxing catalyst.

8. The process of claim 7, wherein the first dewaxing catalyst comprises ZSM-12 in an amount of at least 30 wt. % and at most 60 wt. %.

9. The process of claim 8, wherein the second dewaxing catalyst comprises EU-2 and/or ZSM-48 in an amount of at least 20 wt. % and at most 65 wt. %.

10. The process of claim 9, wherein the first dewaxing catalyst further comprises 0.2 wt. % to 2 wt. % of a noble metal component selected from the group consisting of palladium and platinum, and the second dewaxing catalyst further comprises 0.2 wt. % to 2 wt. % of a noble metal component selected from the group consisting of palladium and platinum.

11. The process of claim 10, wherein the ZSM-12 zeolite has a silica to alumina molar ratio of greater than 60:1 and at most 200:1.

12. The process of claim 11, wherein the EU-2 and/or ZSM-48 zeolite has a silica to alumina molar ratio of at least 70:1 and at most 250:1.

13. The process of claim 12, wherein the catalyst volume ratio of the first dewaxing catalyst to the second dewaxing catalyst is in the range of 20:80 to 90:10.

14. A process, comprising: passing a feed to a reactor system, wherein the reactor system comprises a reactor operated in a top down flow arrangement and loaded with a stacked catalyst system, wherein the stacked catalyst system comprises a first zone containing a first volume of a first dewaxing catalyst, comprising a ZSM-12 zeolite based catalyst, positioned top of the stacked catalyst system, and a second zone containing a second volume of a second dewaxing catalyst, comprising EU-2 and/or ZSM-48 zeolite based catalyst positioned in a lower section of the reactor, wherein the reactor is loaded such that the feed first passes the first dewaxing catalyst followed by the second dewaxing catalyst, wherein the first dewaxing catalyst comprises ZSM-12, having a silica-to-alumina ratio of at least 50:1 to at most 250:1, and in an amount of at least 15 wt. % and at most 70 wt. %, a binder in an amount of at least 30 wt. % and no more than 90 wt. %, and from 0.1 wt. % to about 3 wt. % of a noble metal component selected from the group consisting of palladium and platinum, with such wt. % being based on the dry weight of the first dewaxing catalyst, and wherein the second dewaxing catalyst comprises EU-2 and/or ZSM-48, having a silica-to-alumina ratio of at least 60:1 and at most 300:1, and in an amount of at least 15 wt. % and at most 70 wt. %, a binder in an amount of at least 30 wt. % and no more than 85 wt. %, and from 0.1 wt. % to about 3 wt. % of a noble metal component selected from the group consisting of palladium and platinum, with such wt. % being based on the dry weight of said second dewaxing catalyst.

15. The process of claim 14, wherein the first dewaxing catalyst comprises ZSM-12 in an amount of at least 15 wt. % and at most 60 wt. %.

16. The process of claim 15, wherein the second dewaxing catalyst comprises EU-2 and/or ZSM-48 in an amount of at least 15 wt. % and at most 70 wt. % and a binder in an amount of at least 30 wt. % and no more than 85 wt. %, with such wt. % being based on the dry weight of said second dewaxing catalyst.

17. The process of claim 16, wherein the first dewaxing catalyst further comprises from 0.2 wt. % to 2 wt. % of a noble metal component selected from the group consisting of palladium and platinum, and the second dewaxing catalyst further comprises from 0.2 wt. % to 2 wt. % of a noble metal component selected from the group consisting of palladium and platinum.

18. The process of claim 17, wherein the ZSM-12 zeolite has a silica to alumina molar ratio of at least 60:1 and at most 200:1.

19. The process of claim 18, wherein the EU-2 and/or ZSM-48 zeolite has a silica to alumina molar ratio of greater than 70:1 and at most 250:1.

20. The reactor system of claim 19, wherein the catalyst volume ratio of the first dewaxing catalyst to the second dewaxing catalyst is in the range of 20:80 to 90:10.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 shows performance data of catalyst stacks with ZSM-12 and EU-2 based catalysts when compared to ZSM-12 only and EU-2 only catalysts, respectively. Also the performance data of a ZSM-12/EU-2 catalyst mixture is shown.

(2) Legends: “wof %” is the wt. % on feed. “C1-C4” indicates the amount of product containing 1, 2, 3, or 4 carbon atoms. “C5-150° C.” indicates the amount of product with carbon number 5 up to products that have a boiling point of 150° C. “150-370° C.” indicates the amount of product with a boiling point in the range between 150 and 370° C. “>370° C.” indicates the amount of product with a boiling point of 370° C. or higher as measured with ASTM D2887-93. “Treq.dPP 75° C.” stands for the required reactor temperature to obtain a pour point (PP) improvement of 75° C.

(3) The method of the invention will now be illustrated by the following non-limiting examples.

EXAMPLES

Example 1

(4) ZSM-12 Composition

(5) An extrudable mass was prepared by combining ZSM-12 zeolite having a SAR of 90 from Zeolyst International with amorphous silica, ammonia and water. The mass was extruded to give extrudates having a cylinder shape and an average diameter of 1.6 mm. These extrudates were dried and calcined resulting in white extrudates.

(6) The extrudates were treated unstirred at a temperature of 90° C. for 5 hours with aqueous ammonium hexafluorosilicate (AHS) solution. The weight ratio of solution to extrudates was 5:1. Subsequently, the extrudates were separated from the solution, washed with deionized water, and dried and calcined.

(7) Thereafter, 0.7% wt./wt. platinum was incorporated into the composition by pore volume impregnation during about 10 minutes with an aqueous solution containing tetramine platinum nitrate (Pt(NH3)4(NO3)2) (3.37% wt./wt. Pt).

(8) The impregnated composition was not washed, but equilibrated during 1.5 hours on a rolling bed, dried and calcined. Then, the catalyst was cooled down to room temperature.

Example 2

(9) EU-2 (ZSM-48) Composition

(10) Zeolite EU-2 (ZSM-48) having a SAR of 110 was prepared as described in U.S. Pat. No. 4,741,891 A. An extrudable mass was prepared by combining EU-2 with amorphous silica, ammonia and water. The mass was extruded to give extrudates having a cylinder shape and an average diameter of 1.6 mm. These extrudates were dried and calcined resulting in white extrudates.

(11) The extrudates were treated unstirred at a temperature of 90° C. for 5 hours with aqueous ammonium hexafluorosilicate (AHS) solution. The weight ratio of solution to extrudates was 5:1. Subsequently, the extrudates were separated from the solution, washed with deionized water, and dried and calcined.

(12) Thereafter, 0.7% wt./wt. platinum was incorporated into the composition by pore volume impregnation during about 10 minutes with an aqueous solution containing tetramine platinum nitrate (Pt(NH3)4(NO3)2) (3.3% wt./wt. Pt).

(13) The impregnated composition was not washed, but equilibrated during 1.5 hours on a rolling bed, dried and calcined. Then, the catalyst was cooled down to room temperature.

Example 3

(14) Performance Testing of Stacked Catalysts

(15) The catalysts of Examples 1 and 2 were dried at 250° C. for 3 hours. Subsequently, each of the catalysts was mixed with sufficient inert material (e.g. SiC) to assure proper plug flow conditions and loaded into a single tube test reactor of down flow mode (comparative examples). For preparing the stacked examples, the catalysts—mixed with sufficient inert material—were loaded on top of each other into a single tube test reactor of down flow mode.

(16) In total, 4 stacked examples were prepared: (a) 50% “EU-2”/50% “ZSM-12”; (b) 25% “ZSM-12”/75% “EU-2”; (c) 50% “ZSM-12”/50% “EU-2”; and (d) 75% “ZSM-12”/25% “EU-2”,
wherein “EU-2” refers to the catalyst of Example 2 and “ZSM-12” refers to the catalyst of Example 1.

(17) Thus, e.g. 25% “ZSM-12”/75% “EU-2” means: 25% of the total dewaxing catalyst volume is occupied by the catalyst with ZSM-12 being located in the top of the stack, and 75% of the total dewaxing catalyst volume is occupied by the catalyst with EU-2 being located in the bottom of the stack.

(18) Subsequently, a hydrogen partial pressure was applied of 140 bar and then the temperature was increased from room temperature to 125° C. at a rate of 20° C./h, and held for two hours. The temperature was increased further to 300° C. at a rate of 50° C./h, and held for 8 hours to ensure proper reduction of the metallic phase. The reactor was cooled to 200° C. and then the feed of Table 1 was introduced. After feed breakthrough, the temperature was increased to 250° C. in 4 hours, and held overnight. The feed of Table 1 was added at a weight hourly space velocity of 1.2 kg 1-1 h−1.

(19) TABLE-US-00001 TABLE 1 Feed Density at 70/4° C. g/ml 0.8197 Carbon content wt. % 85.99 Hydrogen content wt. % 14.01 Sulphur content, wt. % 0.001 Nitrogen content, ppmw 0.0004 UV Aromatics Mono-aromatics wt. % 1.47 Di-aromatics wt. % 0.17 Tri-aromatics wt. % 0.09 Tetra+-aromatics wt. % 0.13 Pour Point ° C. 42 TBP-GLC  0.5 wt. % recovery (IBP) ° C. 251   10 wt. % recovery ° C. 358   90 wt. % recovery ° C. 519   98 wt. % recovery ° C. 568 99.5 wt. % recovery ° C. 595

(20) The performance of the catalyst or catalyst stacks was evaluated at temperatures in the range between 330° C. and 350° C.

(21) [Method: The performance of the catalyst (stack) was evaluated at temperatures in the range between 330° C. and 350° C. The performance of the catalyst (stacks) is evaluated at a pour point improvement of 75° C., which means that the product has a pour point which is 75° C. lower than the pour point of the feedstock. The pour points are measured according to ASTM D97. The feed of Table 1 was added at a weight hourly space velocity of 1.2 kg 1-1 h−1.]

(22) The performances of the catalyst/catalyst stacks are shown in FIG. 1. In this FIGURE, the expression wof % stands for the wt. % on feed. C1-C4 stands for the amount of product containing 1, 2, 3, or 4 carbons. C5-150° C. stands for the amount of a hydrocarbon product with carbon number 5 up to products that have a boiling point of 150° C. 150-370° C. stands for the amount of product which has a boiling point that falls in the range between 150 and 370° C.>370° C. stands for the amount of product which has a boiling point of 370° C. or higher as measured with ASTM D2887-93. “Treq.dPP 75° C.” stands for the required reactor temperature to obtain a pour point (PP) improvement of 75° C.

(23) In Table 2 the results are listed with their numerical values.

Example 4

(24) The catalysts of Examples 1 and 2 were dried at 250° C. for 3 hours. Subsequently, a mixture of 75% of the ZSM-12 based catalyst and 25% of the EU-2(ZSM-48) based catalyst was prepared. Then the ZSM-12/EU-2(ZSM-48) catalyst mixture was mixed with 0.1 mm SiC inert material in a 1:1 vol/vol ratio to assure proper plug flow conditions and carefully loaded into a single tube test reactor of down flow mode. This happened in a similar way as in Example 3, where the catalysts were loaded on top of each other. The total catalyst volume was 20 ml. Subsequently, a hydrogen partial was applied of 140 bar and then the temperature was increased from room temperature to 125° C. at a rate of 20° C./h, and held for two hours. The temperature was increased further to 300° C. at a rate of 50° C./h, and held for 8 hours to ensure proper reduction of the metallic phase. The reactor was cooled to 200° C. and then the feed of Table 1 was introduced. After feed breaks through the temperature was increased to 250° C. in 4 hours, and held overnight.

(25) The performance of the catalyst was evaluated according to the method described in Example 3.

(26) The performance of the catalyst mixture is shown in FIG. 1 next to the performance of the catalyst stacks. For an explanation of the numbers and abbreviations in the FIGURE, see Example 3.

(27) In Table 2 the results are listed with their numerical

(28) TABLE-US-00002 TABLE 2 50% EU- 25% ZSM- 50% ZSM- 75% ZSM- 75% ZSM- 100% 2/50% 100% 12/75% 12/50% 12/25% 12/25% label ZSM-12 ZSM-12 EU-2 EU-2 EU-2 EU-2 EU-2 mix Treq. dPP ° C. 336 338 342 339 335 332 335 75° C. Yields: C1-C4 wof % 0.5 0.8 1.1 0.8 0.7 0.6 0.7 C5-150° C. wof % 4.0 4.1 4.0 3.5 3.2 3.2 4.3 150-370° C. wof % 23.7 22.6 19.8 19.2 19.5 20.7 23.5 >370° C. wof % 71.7 72.4 75.0 76.8 76.5 75.7 71.8

CONCLUSION

(29) It can be concluded from the performance data of Examples 3 and 4, that the stacked catalyst system of the present invention with a ZSM-12 based catalyst in the top of the stack and a EU-2 based catalyst in the bottom of the stack exhibits an enhanced performance and an improved base oil yield, not only when compared to a catalyst system containing only a EU-2 based catalyst, but also when compared to a proportionate mixture of both catalysts. Further, the stacked system of the present invention exhibits an improved base oil yield when compared to a catalyst system containing only a ZSM-12 based catalyst, whereas the performance is very well comparable to or even better than a catalyst system containing only a ZSM-12 based catalyst.