|Title of Invention||
"A PROCESS FOR CONVERTING A WAX TO FORM ISOPARAFFINIC LUBE BASESTOCK"
|Abstract||The present invention relates to a process for converting wax with a heavy component to high quality lube basestocks using a unidimensional intermediate pore molecular sieve with near circular pore structures having an average diameter of 0.50 nm to 0.65 nm wherein the difference between the maximum diameter and the minimum is ≤ 0.05 nm followed by a molecular sieve Zeolite Beta catalyst. Both catalysts comprise one or more Group VIII metals. For example, a cascaded two-bed catalyst system consisting of a first bed Pt/ZSM-48 catalyst followed by a second bed Pt/Beta catalyst improves processing of heavy lubes.|
|Full Text||The present invention relates to a process for converting a wax.
The present application has a copending application, 1051/DELNP/2005 having the same filing and priority date as the present application.
1051/DELNP/2005 teaches a new process for converting FT wax into an isoparaffinic lube base stock by passing the FT wax and hydrogen co-feed over a catalyst comprising Zeolite B containing at least one Group VIII metal component to form an intermediate product, and then passing the intermediate product over a catalyst comprising ZSM-48 zeolite and at least one Group VII metal component to form the iosparaffinic lube base stock.
The present invention differs from 1051/DELNP/2005 in that the catalysts used in the first and second separate zones or stages have been reversed.
FIELD OF THE INVENTION
 The present invention relates to a process for converting waxy feeds to lube basestocks with a reduced viscosity.
BACKGROUND OF THE INVENTION
 There is significant economic incentive to convert wax to high quality lube basestocks, especially base oils with properties and performance comparable to, or better than, those of polyalphaolefins (PAO). The upgrading of wax greatly relies on advanced wax isomerization technology that selectively transforms linear paraffins to multi-branched isoparaffins.
 Processes for converting wax to paraffinic lube basestocks are known. A typical process is a two-stage process that hydroisomerizes wax to a waxy isoparaffins mixture in the first step, followed by either solvent dewaxing or catalytic dewaxing the waxy isoparaffins mixture in the second step to remove residual wax and achieve a targetlube pour point.
[00041 The hydroisomerization catalysts disclosed previously, such as Pt supported on amorphous aluminosilicate or Zeolite Beta (Beta), normally possess large pores that allow the formation of branch structures during paraffin isomerization. Examples of other large pore molecular sieves include ZSM-3, ZSM-12, ZSM-20, MCM-37, MCM-68, ECR-5, SAPO-5, SAPO-37 and USY. However, these large pore catalysts are not selective enough to preferentially convert normal and lightly branched paraffin waxes in the presence of multi-branched isoparaffm molecules. As a result, the isoparaffin products derived from wax often contain residual wax that needs to be dewaxed in order to meet target lube cloud points or pour points. The cloud point of a lube is the temperature at which the first trace of wax starts to separate, causing the lube to become turbid or cloudy (e.g., ASTM D2500). The pour point of a lube is the temperature at which lube and wax crystallize together as a whole and will not flow when poured (e.g., ASTM D97). Dewaxing can be achieved by additionally using either a solvent dewaxing process or a catalytic dewaxing process.
 Most selective dewaxing catalysts used in a catalytic dewaxing process have relatively small pore structures and catalyze lube pour point reduction by selectively cracking normal and lightly branched paraffin waxes. Such dewaxing catalysts usually have low paraffin isomerization selectivity.
 Few catalysts have been reported to be efficient in catalyzing both hydroisomerization and dewaxing of paraffin wax to low pour point lubes. Also, such catalysts have difficulty to convert feeds with a high molecular weight component, as a result of which the lube products often appear hazy (or cloudy).
 There remains a need therefore to achieve conversion of high molecular weight wax and a low enough pour point without sacrificing lube isomerization dewaxing selectivity.
SUMMARY OF THE INVENTION
 The present invention relates to a process for converting wax to high quality lube basestocks by contacting the wax with a unidimensional molecular sieve catalyst with a near circular pore structure having an average diameter of 0.50 nm to 0.65 nm wherein the difference between the maximum diameter and the minimum is BRIEF DESCRIPTION OF THE FIGURES
 Figure 1 is a plot of lube yield versus lube pour point for isomerization of C80 wax over Pt/ZSM-48 followed by Pt/Beta, and standalone Pt/ZSM-48 catalyst systems.
 Figure 2 is a plot of lube viscosity versus lube pour point for isomerization of C80 wax over Pt/ZSM-48 followed by Pt/Beta, and standalone Pt/ZSM-48 catalyst systems.
 Figure 3 is a plot of viscosity index (VI) versus lube pour point for isomerization of C80 wax over Pt/ZSM-48 followed by Pt/Beta, and stand alone Pt/ZSM-48 catalyst systems.
 Figure 4 is a plot of light gas yield versus lube pour point for isomerization of C80 wax over Pt/ZSM-48 followed by Pt/Beta, and standalone Pt/ZSM-48 catalyst systems.
 Figure 5 is a plot of naphtha yield versus lube pour point for isomerization of C80 wax over Pt/ZSM-48 followed by Pt/Beta, and standalone Pt/ZSM-48 catalyst systems.
 Figure 6 is a plot of diesel yield versus lube pour point for isomerization of C80 wax over Pt/ZSM-48 followed by Pt/Beta, and standalone Pt/ZSM-48 catalyst systems.
 The invention provides high isomerization and dewaxing selectivity of a wax- over an unidimensional catalyst with a near circular pore structure having an average pore diameter of 0.50-0.65 nm (5.0-6.5 angstroms) wherein the maximum diameter - minimum diameter  The invention improves lube basestock products and their properties (e.g., pour point, cloud point). This method effectively reduces average lube molecular weight and potentially reduces lube product cloud point without sacrificing lube yield. This process allows improved use of the heavy end of lubes and is especially suited for waxes with 1,000°F+ fractions and preferably 1,100°F+ fractions. These fractions may comprise the higher molecular weight or boiling point tail of the feeds. It would be difficult to create enough branches with minimal cracking for very large molecular weight feeds if only one of the above catalysts was used. This invention is preferably used for processing heavy lube or lubes with a heavy component (e.g., with >5 wt% heavy raffmate) where the Beta catalyst selectively cracks the heavy end. This
invention can give a lighter lube with yields similar to those obtained over ZSM-48 alone.
 Preferably, wax feed is first passed over a ZSM-48 catalyst. The resulting intermediate product is then passed over a single Zeolite Beta catalyst to form the final lube. These first and second stages can be separated or preferably are integrated process steps (e.g., cascaded).
 The unidimensional molecular sieve catalyst with near-circular pore structures does most of the dewaxing. The pores are smaller than in large pore molecular sieves thereby excluding bulkier (e.g., highly branched) molecules. Unidimensional means that the pores are essentially parallel to each other.
 The pores of the catalyst have an average diameter of 0.50 nm to 0.65 nm wherein the difference between a minimum diameter and a maximum diameter is  The preferred unidimensional molecular sieve catalyst is an intermediate pore molecular sieve catalyst of which the preferred version is ZSM-48. U.S. Patent 5,075,269 describes the procedures for making ZSM-48 and is incorporated by reference herein. ZSM-48 is roughly 65% zeolite crystal and 35% alumina. Of the crystals, at least 90%, preferably at least 95%,
and most preferably 98-99% are ideal crystals. The ZSM-48 is preferably in the protonated form though some sodium is acceptable. ZSM-48 is more robust than other catalysts with similar functions and helps to protect the second catalyst (e.g., Zeolite Beta).
 In the first stage of the process, the unidimensional intermediate pore molecular sieve catalyst (e.g., Pt/ZSM-48) is preferably kept at 500-800°F (260-427°C), more preferably at 600-700°F (316-371°C), and most preferably at 630-660°F (332-349°C). ZSM-48 catalysts used in the invention preferably have an Alpha value of about 10 to about 50 prior to the Group VIII metal loading.
 Zeolite Beta catalysts are 12 ring acidic silica/alumina zeolites with or without boron (replacing some of the aluminum atoms). Zeolite Y (USY), though less preferred than Beta, is also contemplated in the scope of the invention. Pre-sulfided Zeolite Beta is preferred when some residual sulfur in the product is acceptable.
 Zeolite Betas used in the invention preferably have an Alpha value below 15, more preferably below 10, at least prior to metal loading. Alpha is an acidity metric that is an approximate indication of the catalytic cracking activity of the catalyst compared to a standard catalyst. Alpha is a relative rate constant (rate of normal hexane conversion per volume of catalyst per unit time). Alpha is based on the activity of the highly active silica-alumina cracking catalyst taken as an Alpha of 1 in U.S. Patent 3,354,078 (incorporated by reference) and measured at 538°C as described in the Journal of Catalysis, vol. 4, p. 527 (1965); vol. 6, p. 278 (1966); and vol. 61, p. 395 (1980). Feeds with minimal nitrogen content will require low Alpha value of this catalyst. In
comparison, catalysts with high Alpha values are used for less selective cracking. Alpha values may be reduced by steaming.
 The Beta catalyst (e.g., Pt/Beta), when contacting the intermediate product, is most preferably kept at temperatures of 400-700°F (204-371°C), more preferably at 500-650°F (260-343°C), and most preferably at 520-580°F (271-304°C).
 The temperature of each catalyst is preferably controlled independently. Temperature choice partly depends on the feed liquid hourly space velocity of which 0.1-20 h"1 is preferred, 0.5-5 h"1 is more preferred, and 0.5-2 h"1 is most preferred.
 The contact time for both catalysts is preferably similar to each other. It is understood that the space velocity can be different. The pressure for both catalysts is preferably similar to each other. Hydrogen co-feed flow rate is 100-10,000 scf/bbl (17.8-1,780 n.L.L-1), more preferably 1,000-6,000 scf/bbl (178-1,068 n.L.L-1), and most preferably 1,500-3,000 scf/bbl (267-534 n.L.L-1).
 Each catalyst comprises 0.01-5 wt% of at least one Group VIII metal (i.e., Fe, Ru, Os, Co, Rh, Ir, Pd, Pt, Ni). Platinum and palladium are most preferred. Platinum or palladium blended with each other or other group VIII metals follow in preference. Nickel may also be blended with group VIII precious metals and is included in the scope of the invention whenever group VIII blends, alloys, or mixtures are mentioned. Platinum is the most preferred metal. Preferred metal loading on both catalysts are 0.1-1 wt% with approximately 0.6 wt% most preferred.
 The feed preferably is a wax with a melting point over 50°C, less than 7,000 ppm sulfur, and less than 50 ppm nitrogen. The nitrogen is more preferably less than 10 ppm. nitrogen if hydrogen pressure is below 500 psig (34 arm). For example, a heavy raffinate can be blended with a Fischer-Tropsch wax or similar clean waxy feed (e.g., to lower sulfur and/or nitrogen levels).
 The feed is converted by the first catalyst to form an intermediate product which is then preferably passed directly from the first catalyst to the second catalyst. In a preferred embodiment of the invention, a cascaded two-bed cataiyst system consisting of a first bed catalyst followed by a second bed catalyst allows a highly selective process for wax isomerization and lube hydrodewaxing with minimal gas formation. In cascading, the intermediate product preferably directly passes from the first bed to the second bed without inter-stage removal of light products. Optionally, light byproducts (e.g., methane, ethane) can be removed between the first and second catalysts.
 More branching in feeds facilitates the present invention and improves final lube yield. U.S. Patent 6,090,989 describes typical branching indices and is incorporated by reference. The feed is preferably mixed with hydrogen and preheated before contacting it with the first catalyst. Preferably, at least 95% of the wax is in liquid form before contacting it with the first catalyst.
 The preferred measurements, as taught by the specification, are described in this paragraph. Where there are two values, the value in parenthesis is approximate metric conversion of the first value. The weight
percent of paraffins may be measured by high-resolution iH-NMR, for example, by the method described in ASTM standard D5292, in combination with GC-MS. This approach may also be used to determine the weight percentage of unsaturates, alcohols, oxygenates, and other organic components. The iso- to normal-paraffin ratio may be measured by performing gas chromatography (GC) or GC-MS in combination with 13C-NMR. Sulfur may be measured by XRF (X-Ray Fluorescence), as described, for example, in ASTM standard D2622. Nitrogen may be measured by syringe/inlet oxidative combustion with chemiluminescence detection, for example, by the method described in ASTM standard D4629. Aromatics may be measured as described below. As taught by the specification, olefins may be measured by using a Bromine index determined by coulimetric analysis, for example, by using ASTM standard D2710. The weight percent of total oxygen may be measured by neutron activation in combination with high-resolution ^H-NMR. If necessary, the total oxygen content may be placed on a water-free basis by measuring water content. For samples having a water content known to be less than about 200 ppm by weight, one may use known derivitization methods (e.g., by using calcium carbide to form acetylene) followed by GC-MS. For samples having a water content known to be greater than about 200 ppm by weight, one may use the Karl-Fischer method, for example, by the method described in ASTM standard D4928. The total alcohol content may be determined by high-resolution 1H-NMR, and the percentage present primarily as C12-C24 primary alcohols may be determined by GC-MS. Cetane number may be determined by using, for example, ASTM standard D613. The level of aromatics may be determined by using high-resolution 1H-NMR, for example, by using ASTM standard D5292. Dioxygenates are measured by using infrared (IR) absorbance spectroscopy. Branching characteristics of iso-paraffins may
be measured by a combination of high-resolution13C-NMR and GC with high-resolution MS.
 A cascaded two-bed catalyst system consisting of a first stage Pt/ZSM-48 catalyst immediately followed by a second stage of Pt/Beta catalyst is shown to be highly active and selective for hydroisomerization and dewaxing of waxes with high molecular weight components.
 Example operating conditions, material balance data, lube yields and properties are summarized in Table 1. TBP x% indicates temperature below which x wt% of hydrocarbon samples boils. Time on stream (TOS) is the time during which the feed contacts the catalyst. IBP is initial boiling point. TBP is terminal boiling point. The best S.I. equivalent of standard cubic feed of hydrogen per barrel of feed (SCF/bbl) is normal liters of hydrogen gas per liter of feed (n.1.1"1. or n.L.L"1 or n.L (gas) / L (feed)). LHSV is defined as liquid hourly space velocity. WHSV is defined as weight hourly space velocity.
Hydroisomerization of C80 Wax Catalyzed by a Cascaded Pt/ZSM-48 Followed by Pt/Beta
(1.0 h1 LHSV for Each Catalyst)
TABLE 1 (continued)
 To obtain desirable wax isomerization results, a mild (e.g., 500-630°F (260-332°C)) Pt/Beta temperature should be employed during lube hydroprocessing. The mild Pt/Beta temperature should be employed with varying Pt/ZSM-48 temperature to achieve a target lube pour point. To achieve maximal lube yield, low operating pressure (  Stand-alone Pt/ZSM-48 was also evaluated for isomerizing and dewaxing C80 wax to 700°F+ (371 °C+) lube basestocks (Tables 2). Comparison of lube yields for the two catalyst systems is illustrated in Figure 1. Figure 1 shows that the cascaded Pt/ZSM-48 followed by Pt/Beta gave essentially identical lube yields compared to Pt/ZSM-48 alone. The addition of Pt/Beta had minimal effects on the range of Pt/ZSM-48 operating temperature (Tables 1 and 2).
TABLE 2 Hydroisomerization of JC80 Wax Catalyzed by Pt/ZSM-48
TABLE 2 (continued)
 The viscosity and viscosity index of the nominal 700°F+ (371°C+) C80 wax isomerates vs. hydroprocessing severity are plotted in Figures 2 and 3, respectively. The two sets of data compared in the two diagrams correspond to the wax isomerates prepared using Pt/ZSM-48 followed by Pt/Beta, and stand-alone Pt/ZSM-48.
 As shown in Figure 2, the Pt/ZSM-48-Pt/Beta isomerates had significantly lower viscosities presumably due to the relatively high cracking activity of Pt/Beta catalyst towards multi-branched isoparaffins. Thus, this dual catalysts system provides an effective method for reducing average molecular weight of a wax feed to produce lower viscosity lube stocks without sacrificing lube yield during wax hydroisomerization process.
 Figure 3 shows high viscosity indices observed for the Pt/ZSM-48-Pt/Beta wax isomerates, although they are slightly lower than those of Pt/ZSM-48 isomerates. For products of the invention, a viscosity index of at least 150 at a -20°C lube pour point and a viscosity index of at least 130 at a pour point of no more than -50°C is preferred.
 The spread between the lube cloud and pour points for Pt/ZSM-48-Pt/Beta is mostly less than 15°C (Table 1). In general, the spread between the lube cloud and pour points narrows with decreasing pour point.
 The overall light byproduct selectivity for the two catalyst systems is comparable (Figures 4-6). As expected, the yields of gases, naphtha, and diesel increase for both systems with increasing process severity (decreasing lube pour point) that promotes hydrocracking.
 The following examples will serve to illustrate the invention.
 Feedstock. The hydrotreated SASOL™ PARAFLINT™ C80 wax (C80) feed was obtained from Moore and Munger, Inc., (Shelton, CT) and used as received without additional pretreatment. The C80 wax was a mixture of predominantly linear paraffins with very low content of olefins and oxygenates. SASOL™ has been marketing three commercial grades of waxes: PARAFLINT™ H1, a 700°F+ (371°C+) full range wax; PARAFLINT™ C80 and C105, 700-1100°F (371-593°C) and 1100°F+ (593°C+) distillate fractions, respectively. The molecular weight distribution (in terms of boiling point) of the waxes is illustrated briefly in Table 3.
TABLE 3 Molecular Weight Distribution of Waxes in Examples
 Preparation of Pt/Beta Catalyst. Pt/Beta catalyst was prepared by extruding a water-containing mull mix or paste containing 65 parts of Zeolite Beta with 35 parts of alumina (dry basis). After drying, the Zeolite Beta containing catalyst was calcined under nitrogen at 900°F (482°C) and exchanged at ambient temperature with a sufficient quantity of ammonium
nitrate to remove residual sodium in the zeolite channels. The extrudate was then washed with de-ionized water and calcined in air at 1000°F (538°C). After air calcination, the 65% Zeolite Beta/35% Alumina extrudate was steamed at 1020°F (549°C) to reduce the Alpha value of the calcined catalyst to less than 10. The steamed, 65% low acidity Beta/35% Alumina catalyst was ion exchanged with a tetraammine platinum chloride solution under ion exchange conditions to uniformly produce a catalyst containing 0.6% Pt. After washing with de-ionized water to remove residual chlorides, the catalyst was dried at 250°F (121°C) followed by final air calcination at 680°F (360°C).
 Preparation of Pt/ZSM-48 Catalyst. Pt/ZSM-48 catalyst was prepared by extruding a water-containing mull mix or paste containing 65 parts of ZSM-48 with 35 parts of alumina (dry basis). After drying, the ZSM-48 containing catalyst was calcined under nitrogen at 900°F (482°C) and exchanged at ambient temperature with a sufficient quantity of ammonium nitrate to remove residual sodium in the zeolite channels. The extrudate was then washed with deionized water and calcined in air at 1000°F (538°C). After air calcination, the 65% ZSM-48 / 35% Alumina catalyst was impregnated with a tetraammine platinum nitrate solution under incipient wetness conditions to uniformly produce a catalyst containing 0.6% Pt. Finally, the catalyst was dried at 250°F (121°C) followed by air calcination at 680°F (360°C).
 Wax Hydroprocessing. The wax hydroisomerization experiments were performed using a micro-unit equipped with two three-zone furnaces and two down-flow trickle-bed tubular reactors (1/2" ID) in cascade (with option to bypass the second reactor). The unit was carefully heat-traced to avoid freezing of the high melting point C80 wax. To reduce feed bypassing and lower zeolite pore diffusion resistance, the catalysts extrudates were crushed and sized to 60-80 mesh. The reactors 1 and 2 were then loaded with 15 cc of the 60-80 mesh Pt/ZSM-48 catalyst and the 60-80 mesh Pt/Beta catalyst, respectively. 5 cc of 80-120 mesh sand was also added to both catalyst beds during catalyst loading to fill the void spaces. After pressure testing of the unit, the catalysts were dried and reduced at 400°F (204°C) for one hour under 1 atmosphere (atm), 255 cc/min hydrogen flow. At the end of this period, the flow of pure hydrogen was stopped and flow of H2S (2% in hydrogen) was initiated at 100 cc/min. After H2S breakthrough, the reactors 1 and 2 were gradually heated to 700°F (371°C) and maintained at 700°F (371°C) for 1 h (hour). After the completion of catalyst pre-sulfiding, the gas flow was switched back to pure hydrogen at 255 cc/min rate, and the two reactors were cooled down.
 Hydroisomerization of the C80 wax over a cascaded Pt/ZSM-48 followed by Pt/Beta was conducted at 1.0 h-1 LHSV for each catalyst and 1000 psig (68 atm) with 5500 scf/bbl (979 n.L.L-1) hydrogen circulation rate. The wax isomerization experiments were started first by saturating the catalyst beds with the feed at 400°F (204°C) then heating the reactors to the initial operating temperatures. Material balances were carried out overnight for 16-24 h. Reactor temperatures were then gradually changed to vary pour point.
 Performance of stand-alone Pt/ZSM-48 was evaluated by cooling and bypassing the Pt/Beta catalyst "in the second reactor. The experiments were conducted under identical process conditions (1.0 LHSV, 1000 psig (68 arm), 5500 scf/bbl (979 n.L.L-1) H2) and according to similar procedures used for testing the cascade Pt/ZSM-48 and Pt/Beta combination.
 Product Separation and Analysis. Off-gas samples were analyzed by GC using a 60m DB-1 (0.25 mm ID) capillary column with FID detection. Total liquid products (TLP's) were weighed and analyzed by simulated distillation (Simdis, such as D2887) using high temperature GC. TLP's were distilled into IBP-J30°F (IBP-166°C) naphtha, 330-700°F (166-371°C) distillate, and 700°F+ (371°C+) lube fractions. The 700°F+ (371 °C+) lube fractions were again analyzed by Simdis to ensure accuracy of the actual distillation operations. The pour point and cloud point of700°F+ (371°C+) lubes were measured by D97 and D2500 methods, and their viscosities were determined at both 40°C and 100°C according to D445-3 and D445-5 methods, respectively.
1. A process for converting a wax, having hydrocarbons primarily within
C24-C110 with essentially no sulfur or nitrogen content, to an isoparaffinic
lube basestock, wherein said process employs a two bed catalyst system
characterized by the following steps:
first, passing the wax and a hydrogen co-feed over a first bed of ZSM-48 catalyst comprising a ZSM-48 zeolite and one or more Group VIII metals to form an intermediate product; and
second, passing the intermediate product over a second bed of a Beta catalyst comprising a Zeolite Beta and one or more Group VIII metals;
to form the isoparaffinic lube basestock having a pour point between -9°C and - 54°C, a viscosity index between 165 and 136, a kinematic viscosity at 100°C between 6 and 5 cSt in a yield between 59 and 20 wt% based on feed and wherein the wax comprises 5 wt% to 80 wt% of a 1,100°F+ fraction, based on the total weight of the wax;
the ZSM-48 catalyst is kept at a temperature of 500 to 800°F (260 to 427°C);
the Beta catalyst is kept at a temperature of 400 to 700°F (204 to 371°C);
the wax is passed over the unidimensional molecular sieve catalyst at a feed liquid hourly space velocity of 0.1 to 20 h-1;
the intermediate product is passed over the Beta catalyst at a feed liquid hourly space velocity of 0.1 to 20 h-1;
the hydrogen pressure is less than about 1,500 psig (102 atm) hydrogen, and wherein the hydrogen is circulated at 100 to 10,000 scf/bbl (18 to 1780 n.L.L-1).
2. A process as claimed in claim 1, wherein the unidimensional molecular
sieve catalyst is kept at a temperature of 600 to 700°F (316 to 371°C);
the Beta catalyst is kept at a temperature of 500 to 650°F (260 to 343°C);
the wax is passed over the unidimensional molecular sieve catalyst at a feed liquid hourly space velocity of 0.5 to 2 h-1;
the intermediate product is passed over the Beta catalyst at a feed liquid hourly space velocity of 0.5 to 2 h-1; and
the hydrogen pressure is less than 1,500 psig (102 atm) hydrogen, wherein the hydrogen is circulated at 1,000 to 6,000 scf/bbl (178 to 1068 n.L.L-1).
3. A process as claimed in claim 1, wherein the Group VIII metal on said catalysts is at least one member selected from the group consisting of Pt and Pd; and ZSM-48 zeolite has an Alpha value of 10 to 50 prior to the metal incorporation.
4. A process as claimed in claim 1 or 2, wherein
the wax has a 1,000°F+ high temperature tail;
the ZSM-48 is loaded with 0.5 wt% to 1 wt% of the Group VIII metal, based on the total weight of the ZSM-48;
the Zeolite Beta has an Alpha value less than 15 prior to loading with the Group VIII metal;
the Zeolite Beta is loaded with 0.5 wt% to 1 wt% of the Group VIII metal, based on the total weight of the Zeolite Beta; and
the Group VIII metal is at least one member selected from the group consisting of Pt and Pd.
5. A process as claimed in claim 4, wherein
the Beta catalyst is Pt/Beta; and
the Pt/ZSM-48 and the Pt/Beta are in a cascaded two-bed catalyst system comprising a first bed followed by a second bed, wherein the first bed comprises the Pt/ZSM-48 catalyst and the second bed comprises the Pt/Beta catalyst.
6. A process as claimed in claim 1, wherein
the temperature of the first bed and the temperature of the second bed are controlled independently; and
the intermediate product is cascaded directly to the second bed.
|Indian Patent Application Number||1052/DELNP/2005|
|PG Journal Number||03/2011|
|Date of Filing||17-Mar-2005|
|Name of Patentee||EXXONMOBIL RESEARCH AND ENGINEERING COMPANY|
|Applicant Address||1545 ROUTE 22 EAST, P.O. BOX 900, ANNANDALE, NEW JERSEY 08801-0900, USA|
|PCT International Classification Number||C10G 45/62|
|PCT International Application Number||PCT/US2003/032098|
|PCT International Filing date||2003-10-07|