Methods of producing diesel fuel from non-standard feedstock

Abstract

FIELD: fuel production.SUBSTANCE: invention concerns a method for hydroisomerising a diesel fuel feedstock, which comprises contacting the diesel fuel feedstock with a hydroisomerisation catalyst, wherein the diesel fuel feedstock comprises or is a biocomponent feedstock or a feedstock obtained by Fischer-Tropsch synthesis, and the hydroisomerisation catalyst comprises zeolite SSZ-91. The invention also relates to a method for improving the quality of feedstock for diesel fuels and a method for producing diesel fuel.EFFECT: production of diesel fuel with improved low-temperature properties from non-standard feedstock with increased efficiency and increased yield.37 cl, 2 dwg, 10 tbl, 9 ex

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Patent Application Serial No. 17 / 138,260, filed December 30, 2020, the disclosure of which is incorporated herein in its entirety.TECHNICAL FIELD

[0002] This document describes new methods for hydroisomerizing non-standard feedstocks, such as bio-based feedstocks or feedstocks obtained by Fischer-Tropsch synthesis, using a hydroisomerization catalyst containing zeolite SSZ-91, zeolite SSZ-32x, zeolite SSZ-32, or combinations thereof.BACKGROUND

[0003] It is known that non-standard feedstocks, such as bio-based feedstocks or feedstocks produced by Fischer-Tropsch synthesis, have poor low-temperature properties. It is desirable to produce diesel fuel with improved low-temperature properties to address the problem of fuel filter clogging in cold conditions. Typically, the low-temperature properties of diesel fuel produced from non-standard feedstocks are improved by adding additives to lower the cloud point and / or pour point of the resulting diesel fuel. However, such traditional procedures can be costly and ineffective, for example, reducing diesel fuel yield.

[0004] The object of the present invention is to provide a method for producing diesel fuel with improved low-temperature properties from non-standard feedstock with increased efficiency and increased yield.BRIEF DESCRIPTION OF THE INVENTION

[0005] The present invention relates to methods for efficiently converting non-standard raw materials, such as bio-component raw materials and raw materials obtained by Fischer-Tropsch synthesis, into high-quality products, including diesel fuel with a low pour point and a low cloud point.

[0006] According to the first aspect, a method for hydroisomerizing a diesel fuel feedstock is proposed, wherein the method includes contacting the diesel fuel feedstock with a hydroisomerization catalyst, wherein the diesel fuel feedstock contains or is a biocomponent feedstock or a feedstock obtained by Fischer-Tropsch synthesis, and the hydroisomerization catalyst contains zeolite SSZ-91, zeolite SSZ-32 or zeolite SSZ-32x.

[0007] According to the second aspect, a method for improving the quality of a diesel fuel feedstock is proposed, wherein the method comprises: bringing the diesel fuel feedstock into contact with a hydroisomerization catalyst under hydroisomerization conditions to obtain diesel fuel with a reduced cloud point and a reduced pour point compared to the cloud point and pour point of the diesel fuel feedstock, wherein the diesel fuel feedstock contains or is a biocomponent feedstock or a feedstock obtained by Fischer-Tropsch synthesis, and the hydroisomerization catalyst contains zeolite SSZ-91, zeolite SSZ-32 or zeolite SSZ-32x.

[0008] According to a third aspect, the present document provides the use of a hydroisomerization catalyst containing zeolite SSZ-91, zeolite SSZ-32 or zeolite SSZ-32x for producing diesel fuel characterized by a lower cloud point and a lower pour point compared to the cloud point and pour point of a diesel fuel feedstock from which the diesel fuel is obtained, wherein the diesel fuel is obtained by contacting the diesel fuel feedstock and the hydroisomerization catalyst, and the diesel fuel feedstock contains a biocomponent feedstock or a feedstock obtained by Fischer-Tropsch synthesis.

[0009] It will be apparent to one skilled in the art that, except where mutually exclusive, features described with respect to any of the above aspects may be applied mutatis mutandis to any other aspect. Furthermore, except where mutually exclusive, any feature described herein may be applied to any aspect and / or combined with any other feature described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Fig. 1 is a schematic representation of a method for hydroisomerizing a diesel fuel feedstock in accordance with one embodiment of the present invention.

[0011] Fig. 2 is a schematic diagram of a method for hydroisomerizing diesel fuel feedstock in accordance with one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION Introduction

[0012] The term "non-standard feedstock" as used herein refers to bio-based feedstocks and feedstocks obtained by Fischer-Tropsch synthesis. The non-standard feedstock has a boiling range suitable for producing diesel fuel therefrom. In embodiments, the non-standard feedstock has a boiling point in the range of about 250 °F (121 °C) to about 900 °F (482 °C), for example, from about 300 °F (149 °C) to about 900 °F (482 °C) or from about 250 °F (121 °C) to about 800 °F (427 °C).

[0013] As used herein, the term "bio-based feedstock" refers to a diesel fuel feedstock derived from a source containing a bio-based component, such as a plant-based oil or fat, an animal-based oil or fat, a fish-based oil or fat, or an algae-based oil or fat. In embodiments, the biocomponent feedstock has a boiling point in the range of about 250 °F (121 °C) to about 900 °F (482 °C), such as about 300 °F (149 °C) to about 900 °F (482 °C), about 400 °F to about 900 °F (about 204 °C to about 482 °C), about 500 °F to about 900 °F (about 260 °C to about 482 °C), about 600 °F (316 °C) to about 900 °F (482 °C), or about 700 °F (371 °C) to about 900 °F (482 °C) at atmospheric pressure. In embodiments, the biocomponent feedstock has a 90% distillation temperature of less than about 700°F (371°C), such as less than about 650°F (343°C).In embodiments, the biocomponent feedstock has a 90% distillation temperature in the range of about 550 °F (288 °C) to about 750 °F (399 °C), such as about 550 °F (288 °C) to about 700 °F (371 °C), about 600 °F (316 °C) to about 700 °F (371 °C). The 90% distillation temperature can be determined in accordance with ASTM D 2887. In embodiments, the biocomponent feedstock has a 5% distillation temperature in the range of about 250 °F (121 °C) to about 600 °F (316 °C), such as about 300 °F (149 °C) to about 600 °F (about 316 °C) or about 400 °F (204 °C) to about 600 °F (316 °C). The 5% distillation temperature can be determined in accordance with ASTM D 2887. In embodiments, the biocomponent feedstock has a 90% distillation temperature in the range of about 550 °F (about 288 °C) to about 750 °F (about 399 °C), and a 5% distillation temperature in the range of about 250 °F (121 °C) to about 600 °F (316 °C).In embodiments, the biocomponent feedstock has a 90% distillation temperature in the range of about 550 °F (288 °C) to about 700 °F (371 °C), and a 5% distillation temperature in the range of about 300 °F (149 °C) to about 600 °F (316 °C). In embodiments, the biocomponent feedstock has a 90% distillation temperature that is greater than about 600 °F (316 °C), for example, from about 605 °F (about 318 °C) to about 675 °F (357 °C), and a 5% distillation temperature that is less than about 600 °F (316 °C), for example, from about 540 °F (282 °C) to about 580 °F (304 °C). In embodiments, the biocomponent feedstock has a 90% distillation temperature in the range of equal to or greater than about 600 °F (316 °C) to about 700 °F (371 °C) and a 5% distillation temperature in the range of about 400 °F (204 °C) to equal to or less than about 600 °F (316 °C).

[0014] The term "Fischer-Tropsch synthesis feedstock" as used herein refers to a synthetic diesel fuel feedstock obtained by the Fischer-Tropsch process and having a 90% distillation temperature of less than about 750 °F (399 °C), for example, less than about 700 °F (371 °C). In embodiments, the Fischer-Tropsch synthesis feedstock has a 90% distillation temperature in the range of from about 550 °F (288 °C) to about 750 °F (399 °C), for example, from about 550 °F (288 °C) to about 700 °F (371 °C) or from about 600 °F (316 °C) to about 700 °F (371 °C). The distillation temperature of 90% can be determined according to ASTM D 2887.In embodiments, the feedstock obtained by Fischer-Tropsch synthesis has a 5% distillation temperature in the range of about 250 °F (121 °C) to about 600 °F (316 °C), such as about 300 °F (149 °C) to about 600 °F (316 °C), or about 340 °F (171 °C) to about 600 °F (316 °C), or about 340 °F (171 °C) to about 500 °F (260 °C), or about 340 °F (171 °C) to about 400 °F (204 °C). The 5% distillation temperature can be determined in accordance with ASTM D 2887. In embodiments, the feedstock obtained by Fischer-Tropsch synthesis has a 90% distillation temperature in the range of about 550 °F (288 °C) to about 750 °F (399 °C), and a 5% distillation temperature in the range of about 250 °F (121 °C) to about 600 °F (316 °C). In embodiments, the feedstock obtained by Fischer-Tropsch synthesis has a 90% distillation temperature in the range of about 550 °F (288 °C) to about 700 °F (371 °C), and a 5% distillation temperature in the range of about 300 °F (149 °C) to about 600 °F (316 °C).In embodiments, the feedstock obtained by Fischer-Tropsch synthesis has a 90% distillation temperature in the range of about 600 °F (316 °C) to about 700 °F (371 °C), and a 5% distillation temperature in the range of about 340 °F (171 °C) to about 600 °F (316 °C). In embodiments, the feedstock obtained by Fischer-Tropsch synthesis has a 90% distillation temperature in the range of about 600 °F (316 °C) to about 700 °F (371 °C), and a 5% distillation temperature in the range of about 340 °F (171 °C) to about 500 °F (260 °C). In embodiments, the feedstock obtained by Fischer-Tropsch synthesis has a 90% distillation temperature in the range of about 600 °F (316 °C) to about 700 °F (371 °C), and a 5% distillation temperature in the range of about 340 °F (171 °C) to about 400 °F (204 °C).In embodiments, the "Fischer-Tropsch synthesis feedstock" may have a boiling point in the range of about 250 °F (121 °C) to about 900 °F (482 °C), such as about 250 °F (121 °C) to about 800 °F (427 °C) at atmospheric pressure.

[0015] The term "diesel fuel" is used herein to mean a hydrocarbon product having a boiling point in the range of about 300°F to about 800°F (about 149°C to about 427°C) at atmospheric pressure.

[0016] The term "active source" means a reagent or precursor material capable of supplying at least one element in a reactive form that can be incorporated into the structure of a molecular sieve. The terms "source" and "active source" may be used interchangeably herein.

[0017] The terms "molecular sieve" and "zeolite" are synonymous and include (a) intermediate and (b) final or target molecular sieves and molecular sieves obtained by (1) direct synthesis or (2) post-crystallization processing (secondary modification). Secondary synthesis methods allow the target material to be synthesized from an intermediate material by substitution of lattice heteroatoms or by other methods. For example, an aluminosilicate can be synthesized from an intermediate borosilicate by post-crystallization substitution of Al lattice heteroatoms with B. Such methods are known, for example, as described in U.S. Patent No. 6,790,433 to C. Y. Chen and Stacey Zones, issued September 14, 2004.

[0018] The terms "molecular sieve type *MRE", "molecular sieve type EUO" and "molecular sieve type MTT" include all molecular sieves and their isotypes to which an International Zeolite Association lattice type has been assigned, as described in Atlas of Zeolite Lattice Types, edited by C. Baerlocher, L. B. McCusker and D. H. Olson, Elsevier, 6 -е revised edition, 2007, and in the Zeolite Structure Database on the website of the International Zeolite Association (http: / / www.iza-online.org).

[0019] The SiO2 / Al2O3 ratio (SAR) is determined using elemental analysis with inductively coupled plasma (ICP). A SAR of infinity (∞) represents the case when there is no aluminum in the zeolite, i.e., the silica-to-alumina molar ratio is infinite. In this case, the molecular sieve consists essentially of silica.

[0020] For the purposes of this document, the term "pour point" refers to the temperature at which an oil begins to flow under controlled conditions. Pour point can be determined according to ASTM D5950.

[0021] For the purposes of this document, "cloud point" refers to the temperature at which a sample begins to fog when the oil is cooled under specified conditions. Cloud point can be determined according to ASTM D5773.

[0022] “Group 2, 8, 9, and 10 metals” refers to elemental metal(s) selected from Groups 2, 8, 9, and 10 of the periodic table of the elements and / or metal compounds containing such metal(s). “Group 6 metals” refers to elemental metal(s) selected from Group 6 of the periodic table of the elements and / or metal compounds containing such metal(s).

[0023] The term "periodic table" refers to the December 1, 2018 version of the IUPAC periodic table of the elements.

[0024] Unless otherwise specified, the "feed rate" of hydrocarbon feedstock fed to the catalytic reaction zone is expressed in this document as a volume of feedstock per volume of catalyst per hour, which may be referred to as liquid hourly space velocity (LHSV) with units inversely proportional to hours (h -1 ).

[0025] The term "hydrotreating" refers to processes or steps carried out in the presence of hydrogen to hydrodesulfurize, hydrodenitrogenate, hydrodemetallize, and / or hydrodearomatize components (e.g., impurities) of diesel fuel feedstocks and / or to hydrogenate unsaturated compounds in the feedstock.

[0026] For the purposes of this description and the appended claims, unless otherwise indicated, it is understood that all numbers expressing quantities, percentages or proportions, and other numerical values ​​used in the description and claims are modified in all instances by the term "about." Accordingly, unless otherwise indicated, the numerical parameters given in the following description and the appended claims are approximate and may vary depending on the desired properties sought to be achieved. It is also noted that the singular forms used in this description and the appended claims include references to plural forms unless they are clearly and unambiguously limited to the singular.As used herein, the word "include" and its grammatical variations are not intended to be limiting, so that the recitation of elements in a list does not exclude other similar elements that may be replaced or added to the listed elements. As used herein, the term "comprising" means the inclusion of elements or steps listed after that term, but any such elements or steps are not exhaustive, and an embodiment may include other elements or steps.

[0027] Unless otherwise specified, the listing of the genus of elements, materials, or other components from which an individual component or mixture of components may be selected is intended to include all possible subgeneric combinations of the listed components and mixtures thereof. Furthermore, all ranges of numbers presented herein include upper and lower limit values.

[0028] If a standard test is referred to in this document, unless otherwise stated, the version of the test referred to is the most recent one at the time of filing of this patent application.

[0029] The patentable scope is defined by the claims and may include other examples that will be obvious to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal wording of the claims, or if they include equivalent structural elements with insubstantial differences from the literal wording of the claims. To the extent not inconsistent with this document, all references cited herein are incorporated by reference. DIESEL FUEL RAW MATERIAL

[0030] The diesel fuel feedstock described herein comprises or is a biocomponent feedstock or a feedstock obtained by Fischer-Tropsch synthesis. In embodiments, the diesel fuel feedstock comprises, consists essentially of, or consists of a biocomponent feedstock. In embodiments, the biocomponent feedstock makes up at least about 5 wt.% of the diesel fuel feedstock, such as at least about 10 wt.%, at least about 20 wt.%, at least about 30 wt.%, at least about 40 wt.%, at least about 50 wt.%, at least about 60 wt.%, at least about 70 wt.%, at least about 80 wt.%, at least about 90 wt.%, at least about 95 wt.%, at least about 98 wt.%, or at least about 99 wt.% of the diesel fuel feedstock. In embodiments, the biocomponent feedstock comprises from 5 wt.% to 100 wt.% of the diesel fuel feedstock, such as from 10 wt.% to 100 wt.%, from 50 wt.% to 100 wt.%, from 80 wt.% to 100 wt.%, from 95 wt.% to 100 wt.% of the diesel fuel feedstock. In embodiments, the diesel fuel feedstock comprises, consists essentially of, or consists of a feedstock obtained by Fischer-Tropsch synthesis. In embodiments, the Fischer-Tropsch feedstock comprises at least about 5 wt.% of the diesel fuel feedstock, such as at least about 10 wt.%, at least about 20 wt.%, at least about 30 wt.%, at least about 40 wt.%, at least about 50 wt.%, at least about 60 wt.%, at least about 70 wt.%, at least about 80 wt.%, at least about 90 wt.%, at least about 95 wt.%, at least about 98 wt.%, or at least about 99 wt.% of the diesel fuel feedstock. In embodiments, the Fischer-Tropsch feedstock comprises from 5 wt.% to 100 wt.% of the diesel fuel feedstock, such as from 10 wt.% to 100 wt.%, from 50 wt.% to 100 wt.%, from 80 wt.% to 100 wt.%, from 95 wt.% to 100 wt.% of raw materials for diesel fuel.

[0031] In embodiments, the diesel fuel feedstock is a blended diesel fuel feedstock comprising a bio-component feedstock or a feedstock obtained by Fischer-Tropsch synthesis in combination with another diesel fuel feedstock, such as the blended feedstock described below. For example, the blended diesel fuel feedstock may comprise a blended feedstock selected from gas oils, vacuum gas oils, atmospheric distillation residues, vacuum distillation residues, atmospheric distillates, heavy fuels, oils, waxes and paraffins, waste oils, deasphalted residues or crude oil, blends obtained from thermal or catalytic conversion processes, or a combination thereof. In embodiments, the blended feedstock is selected from whole crude oil, lightly cracked oil, heavy residues of vacuum distillation column fractions, cyclic oils, synthetic petroleum feedstocks, gas oils, vacuum gas oils, oils separated from wax sweating,Fischer-Tropsch paraffin derivatives, lubricating oil feedstocks, heating oils, heavy neutral feedstocks, hydrotreated gas oils, hydrocracked gas oils, hydrotreated lubricating oil raffinates, high viscosity cylinder oils, lubricating oil feedstocks, synthetic oils, high pour point polyolefins (e.g., polyolefins with a pour point of about 0°C or higher); conventional alpha olefin paraffins, crude paraffins, de-oiled paraffins and microcrystalline paraffins, residual fractions from an atmospheric distillation process; solvent residues of deasphalted oils, shale oils, cyclic oils, petroleum wax, crude paraffin and paraffins obtained from chemical plant processes. In embodiments, the diesel fuel feedstock is a blended diesel fuel feedstock containing a bio-component feedstock and a feedstock,obtained by Fischer-Tropsch synthesis. In embodiments, the diesel fuel feedstock is a blended diesel fuel feedstock comprising a biocomponent feedstock, a feedstock obtained by Fischer-Tropsch synthesis, and a blended feedstock (e.g., a blended feedstock as described above).

[0032] In embodiments, the diesel fuel feedstock is a mixed diesel fuel feedstock comprising a biocomponent feedstock and a mixed feedstock, wherein the mixed diesel fuel feedstock comprises at least about 5 wt.% biocomponent feedstock and up to about 95 wt.% mixed feedstock, such as at least about 10 wt.% biocomponent feedstock and up to about 90 wt.% mixed feedstock, at least about 50 wt.% biocomponent feedstock and up to about 50 wt.% mixed feedstock, at least about 80 wt.% biocomponent feedstock and up to about 20 wt.% mixed feedstock, or at least about 95 wt.% biocomponent feedstock and up to about 5 wt.% mixed feedstock.

[0033] In embodiments, the diesel fuel feedstock is a blended diesel fuel feedstock comprising a Fischer-Tropsch feedstock in combination with a blended feedstock, wherein the blended diesel fuel feedstock comprises at least about 5 wt. % Fischer-Tropsch feedstock and up to about 95 wt. % of the blended feedstock, such as at least about 10 wt. % Fischer-Tropsch feedstock and up to about 90 wt. % of the blended feedstock, at least about 50 wt. % Fischer-Tropsch feedstock and up to about 50 wt. % of the blended feedstock, at least about 80 wt. % Fischer-Tropsch feedstock and up to about 20 wt. % of the blended feedstock, or at least about 95 wt. % Fischer-Tropsch feedstock and up to about 5 wt.% of mixed raw materials. Biocomponent raw materials

[0034] In embodiments, the diesel fuel feedstock comprises, consists essentially of, or consists of a biocomponent feedstock. Vegetable-based oils and fats include vegetable oils and fats such as rapeseed (canola) oil, soybean oil, coconut oil, sunflower oil, palm oil, palm kernel oil, peanut oil, flaxseed oil, tall oil, corn oil, castor oil, jatropha oil, jojoba oil, olive oil, flaxseed oil, camelina oil, safflower oil, babassu oil, tall oil, and rice bran oil. Animal oils and fats include beef tallow (rendered), pork fat (lard), turkey fat, fish oil / oil, and chicken fat), including fats / oils from algae and fish. In embodiments, the biocomponent raw material is selected from vegetable oils and animal fats containing or consisting essentially of triglycerides and free fatty acids (FFA).

[0035] In embodiments, the triglycerides and FFA contain in their structure aliphatic hydrocarbon chains with 6-24 carbon atoms (e.g., 8-24, 8-20, or 10-16 carbon atoms). In embodiments, the biocomponent raw material contains triglycerides having the general formula (1):

[0036] where R, R 1 and R 2 independently represent aliphatic hydrocarbon chains having from 6 to 24 carbon atoms (e.g., from 8 to 24, from 8 to 20, 10 to 20, 10 to 18, or 10 to 16 carbon atoms). In embodiments R, R 1 and R 2 are independently branched or unbranched, substituted or unsubstituted, fully saturated, or contain one or more (e.g., 1-4, 1-3, or 1 or 2) unsaturated carbon-carbon bonds. In embodiments R, R 1 and R 2 are unsubstituted. In embodiments R, R 1 and R 2are independently fully saturated or contain one or more (e.g., 1-4, 1-3, or 1 or 2) unsaturated carbon-carbon bonds. In embodiments, R, R 1 and R 2 are unbranched.

[0037] In embodiments, the biocomponent feedstock comprises free fatty acids (FFAs) having aliphatic hydrocarbon tails in an amount of from 6 to 24 carbon atoms, such as from 8 to 24 carbon atoms, from 8 to 20 carbon atoms, from 10 to 20 carbon atoms, from 10 to 18 carbon atoms, or 10-16 carbon atoms. In embodiments, the FFAs comprise unsaturated or saturated aliphatic hydrocarbon tails. In embodiments, the FFAs comprise straight-chain or branched aliphatic hydrocarbon tails.

[0038] In embodiments, the biocomponent raw material is selected from canola oil, corn oil, soybean oil, castor oil, camelina oil, palm oil, and combinations thereof.

[0039] In embodiments, the biocomponent feedstock has an oxygenate content of at least about 0.5 wt.% of the total weight of the biocomponent feedstock, such as at least about 1.0 wt.%, at least about 2.0 wt.%, at least about 3.0 wt.%, at least about 4.0 wt.%, or at least about 5.0 wt.% of the total weight of the biocomponent feedstock. In embodiments, the biocomponent feedstock has an oxygenate content of up to about 15 wt.% of the total weight of the biocomponent feedstock, such as up to about 10 wt.% of the total weight of the biocomponent feedstock, or up to about 5 wt.% of the total weight of the biocomponent feedstock. In embodiments, the biocomponent feedstock has an oxygenate content in the range of about 1-15 wt.% of the total weight of the biocomponent feedstock, such as in the range of about 5-15 wt.% or about 10-15 wt.% of the total weight of the biocomponent feedstock.The oxygenate content of biocomponent raw materials can be measured using neutron activation analysis, for example, in accordance with ASTM E385-90(2002).

[0040] In embodiments, the biocomponent feedstock is hydrotreated prior to contact with the hydroisomerization catalyst. In embodiments, the sulfur (S) content of the biocomponent feedstock is less than about 200 ppm, such as less than about 100 ppm, less than about 50 ppm, or less than about 20 ppm. In embodiments, the nitrogen (N) content of the biocomponent feedstock is less than about 50 ppm, such as less than about 20 ppm, or less than about 10 ppm. In embodiments, the oxygenate content of the hydrotreated biocomponent feedstock is typically about 0 wt.%, or alternatively less than about 2 wt.%, or 5 wt.%. The nitrogen content of the biocomponent feedstock can be determined in accordance with ASTM D4629. The sulfur content of bio-based feedstocks can be determined in accordance with ASTM D2622. Feedstocks obtained by Fischer-Tropsch synthesis

[0041] In embodiments, the diesel fuel feedstock comprises, consists essentially of, or consists of a feedstock obtained by Fischer-Tropsch synthesis. The feedstock obtained by Fischer-Tropsch synthesis typically has a paraffin content of at least about 90 wt.%, such as at least about 95 wt.% or at least about 97.5 wt.%. The feedstock obtained by Fischer-Tropsch synthesis typically contains only very minor amounts of olefins and cycloparaffins, such as less than about 1.0 wt.% olefin, or less than about 0.5 wt.% olefin and / or less than about 1.0 wt.% cycloparaffin, less than about 0.5 wt.% cycloparaffin, or less than about 0.1 wt.% cycloparaffin. In embodiments, the S content of the Fischer-Tropsch feedstock is less than about 50 ppm, such as less than about 20 ppm. In embodiments, the N content of the Fischer-Tropsch feedstock is less than about 50 ppm, such as less than about 20 ppm.In embodiments, the metal content of the Fischer-Tropsch feedstock is less than about 10 ppm, such as less than about 5 ppm. The paraffin content and cycloparaffin content of the Fischer-Tropsch feedstock can be determined by GC-FIMS analysis as described in the publication "Diesel Fuel Analysis by GC-FIMS: Normal Paraffins, Isoparaffins and Cycloparaffins", Briker, Y., et al., Energy Fuels 2001, 15, 4, 996-1002. The nitrogen content of the Fischer-Tropsch feedstock can be determined in accordance with ASTM D3228-20. The sulfur content of the Fischer-Tropsch feedstock can be determined in accordance with ASTM D4629. The metal content of Fischer-Tropsch synthesis feedstock can be measured using inductively coupled plasma atomic emission spectroscopy (ICP-AES).HYDROISOMERIZATION CATALYST.

[0042] The term "hydroisomerization catalyst" as used herein refers to a hydroisomerization catalyst comprising zeolite SSZ-91, zeolite SSZ-32, zeolite SSZ-32x, or combinations thereof, as described below.

[0043] In embodiments, the hydroisomerization catalyst comprises from about 5 to about 95 wt. % zeolite SSZ-91, zeolite SSZ-32, or zeolite SSZ-32x based on the total weight of the hydroisomerization catalyst, such as from about 10 to about 95 wt. % zeolite SSZ-91, zeolite SSZ-32, or zeolite SSZ-32x, from about 20 to about 90 wt. % zeolite SSZ-91, zeolite SSZ-32, or zeolite SSZ-32x, from about 25 to about 85 wt. % zeolite SSZ-91, zeolite SSZ-32, or zeolite SSZ-32x, from about 30 to about 80 wt. % zeolite SSZ-91, SSZ-32 zeolite or SSZ-32x zeolite, or from about 35 to about 75 wt.% SSZ-91 zeolite, SSZ-32 zeolite or SSZ-32x zeolite, or from about 35 to about 65 wt.% SSZ-91 zeolite, SSZ-32 zeolite or zeolite SSZ-32x, or from about 35 to about 55 wt.% SSZ-91 zeolite, SSZ-32 zeolite or SSZ-32x zeolite, or from about 45 to about 75 wt.% SSZ-91 zeolite, SSZ-32 zeolite or SSZ-32x zeolite, or from about 55 to about 75 wt.% of zeolite SSZ-91, zeolite SSZ-32 or zeolite SSZ-32x based on the total weight of the hydroisomerization catalyst.

[0044] The hydroisomerization catalyst further comprises a metal modifier, for example, a metal modifier selected from metals of groups 2, 8, 9, and 10, or combinations thereof. In embodiments, the metal modifier is selected from metals of groups 8, 9, or 10, and combinations thereof, for example, the metal modifier can be selected from Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, and combinations thereof. In embodiments, the metal modifier is selected from metals of group 10, and combinations thereof. In embodiments, the hydroisomerization catalyst comprises platinum.

[0045] In embodiments, the hydroisomerization catalyst comprises from about 0.05 to about 2.0 wt.% of a metal modifier (e.g., selected from metals of groups 2, 8, 9, and 10, or a metal of groups 8, 9, or 10, for example, a metal of group 10, such as platinum) based on the total weight of the hydroisomerization catalyst, such as from about 0.1 to about 1.5 wt.%, or from about 0.2 to about 1.5 wt.%, or from about 0.1 to about 1 wt.% based on the total weight of the hydroisomerization catalyst.

[0046] In embodiments, the hydroisomerization catalyst comprises an oxide binder. In embodiments, the oxide binder is an inorganic oxide. In embodiments, the hydroisomerization catalyst comprises an oxide binder selected from alumina, silica, cerium, titanium dioxide, tungsten oxide, zirconia, and combinations thereof. In embodiments, the hydroisomerization catalyst comprises an oxide binder comprising alumina. Suitable aluminas are commercially available, including, for example, Catapal aluminas. ® and Pural ® from Sasol ® or Versal aluminas ® from UOP ®. In general, the alumina may be any alumina known for use as a matrix material in the catalyst base. For example, the alumina may be boehmite, bayerite, γ-alumina, η-alumina, θ-alumina, δ-alumina, χ-alumina, or a mixture thereof. In embodiments, the hydroisomerization catalyst comprises from about 5 to about 95 wt.% oxide binder based on the total weight of the hydroisomerization catalyst, such as from about 5 to about 80 wt.% oxide binder, from about 10 to about 70 wt.% oxide binder, from about 20 to about 70 wt.% oxide binder, such as from about 25 to about 65 wt.% oxide binder based on the total weight of the hydroisomerization catalyst.

[0047] In embodiments, the hydroisomerization catalyst comprises: from about 5 to about 95 wt.% zeolite SSZ-91, zeolite SSZ-32, or zeolite SSZ-32x; from about 0.05 to about 2.0 wt.% metal of groups 8-10; and from about 5 to about 95 wt.% oxide binder based on the total weight of the hydroisomerization catalyst.

[0048] In embodiments, the hydroisomerization catalyst comprises: from about 30 to about 80 wt.% zeolite SSZ-91, zeolite SSZ-32, or zeolite SSZ-32x; from about 0.1 to about 1.5 wt.% metal of groups 8-10; and from about 20 to about 70 wt.% oxide binder based on the total weight of the hydroisomerization catalyst. Zeolite SSZ-91

[0049] Zeolite SSZ-91 and methods for producing zeolite SSZ-91 are described in US-A-9920260, which is incorporated herein by reference in its entirety. Zeolite SSZ-91 may also be referred to as molecular sieve SSZ-91.

[0050] The SSZ-91 zeolite has a SiO2 / Al2O3(SAR) molar ratio of 40 to 220. In embodiments, the SSZ-91 zeolite has a SiO2 / Al2O3(SAR) molar ratio of 40 to 200, such as 70 to 200, 80 to 200, 70 to 180, 80 to 180, 70 to 160, 80 to 160, 70 to 140, 80 to 140, 100 to 160, 100 to 140, or 120 to 140. The SAR is determined using inductively coupled plasma (ICP) elemental analysis.

[0051] Zeolite SSZ-91 consists of at least 70% polytype 6 of the total ZSM-48-type material present in the product. The fraction of polytype 6 of the total ZSM-48-type material present in the product is determined using DIFFaX modeling and as described by Lobo and Koningsveld in J. Am. Chem. Soc. 2012, 124, 13222–13230, where disorder was tuned by three different fault probabilities. It should be noted that the phrase “at least X %” includes the case where there are no other ZSM-48 polytypes in the structure, i.e., the material is 100% polytype 6. The structure of polytype 6 is described by Lobo and Koningsveld. ( Cm., J. Am. Chem. Soc. 2002, 124, 13222-13230). In embodiments, the SSZ-91 material consists of at least 80% polytype 6 of the total amount of ZSM-48 type material present in the product. In embodiments, the SSZ-91 material consists of at least 90% polytype 6 of the total amount of ZSM-48 type material present in the product. The structure of polytype 6 has been assigned the lattice code *MRE by the Commission on Structure of the International Zeolite Association.

[0052] Zeolite SSZ-91 has a morphology characterized as polycrystalline aggregates containing crystallites that collectively have an average aspect ratio in the range of 1 to 8. In embodiments, zeolite SSZ-91 has a morphology characterized as polycrystalline aggregates containing crystallites that collectively have an average aspect ratio in the range of 1 to 6, such as 1 to 5, 1 to 4, or 1 to 3.

[0053] In embodiments, the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates having a diameter of about 100 nm to 1.5 μm, each of the aggregates consisting of a plurality of crystallites having an average aspect ratio in the range of 1 to 8. In embodiments, the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates having a diameter of about 100 nm to 1.5 μm, each of the aggregates consisting of a plurality of crystallites having an average aspect ratio in the range of 1 to 6, such as 1 to 5, 1 to 4, or 1 to 3. As used herein, the term "diameter" refers to the shortest length at the short end of each crystallite under consideration.

[0054] Zeolite SSZ-91 is a substantially phase-pure material. As used herein, the term "substantially phase-pure material" means that the material is completely free of zeolite phases other than those belonging to the ZSM-48 family of zeolites, or is present in amounts that have a less measurable effect on the material's selectivity or impart a less significant disadvantage. Two common phases that co-crystallize with SSZ-91 are EUO-type molecular sieves such as EU-1, as well as magadiite and kenyaite. These additional phases may be present as separate phases or may contain intergrown SSZ-91.

[0055] In embodiments, the SSZ-91 zeolite comprises an EUO-type molecular sieve phase in an amount in the range of 0 to 7 wt.% by weight of the total amount of the SSZ-91 zeolite product. In embodiments, the SSZ-91 zeolite comprises an EUO-type molecular sieve phase in an amount of 0 to 5.0 wt.%, such as 0 to 4.0 wt.% or 0 to 3.5 wt.%. In embodiments, the SSZ-91 zeolite comprises an EUO-type molecular sieve phase in an amount of 0.1 to 7.0 wt.%, such as 0.1 to 5.0 wt.%, 0.1 to 4.0 wt.% or 0.1 to 3.5 wt.%. In embodiments, the SSZ-91 zeolite comprises from 0 to 7 wt.% EU-1, such as from 0 to 5.0 wt.% EU-1, from 0 to 4.0 wt.% EU-1, from 0 to 3.5 wt.% EU-1, from 0.1 to 7.0 wt.% EU-1, 0.1 to 5.0 wt.% EU-1, 0.1 to 4.0 wt.% EU-1, 0.1 to 3.5 wt.% EU-1, 0.1 to 2 wt.% EU-1, or 0.1 to 1 wt.% EU-1.

[0056] It is known that the ratio of peak intensities of powder X-ray diffraction varies linearly with the mass fractions for any two phases in a mixture: (Iα / Iβ)=(RIRα / RIRβ)*(xα / xβ), where the RIR (reference relative intensity) parameters can be found in the Powder Diffraction File (PDF) database of the International Center for Diffraction Data (http: / / www.icdd.com / products / ). Therefore, the mass percentage of the EUO phase in zeolite SSZ-91 can be calculated by measuring the ratio between the peak intensity of the EUO phase and the SSZ-91 phase.

[0057] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to alumina (Al2O3) of 40 to 220; at least 70% polytype 6 of the total amount of ZSM-48 type material; 0 to 7.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 8.

[0058] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to aluminum oxide (Al2O3) of 40 to 220; at least 70% polytype 6 of the total amount of ZSM-48 type material; 0 to 4.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 8.

[0059] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to aluminum oxide (Al2O3) of 40 to 220; at least 70% polytype 6 of the total amount of ZSM-48 type material; 0 to 3.5 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 8.

[0060] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to aluminum oxide (Al2O3) of 40 to 200; at least 70% polytype 6 of the total amount of ZSM-48 type material; 0 to 4.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 8.

[0061] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to aluminum oxide (Al2O3) of 70 to 200; at least 70% polytype 6 of the total amount of ZSM-48 type material; 0 to 4.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 6.

[0062] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to aluminum oxide (Al2O3) of 80 to 200; at least 70% polytype 6 of the total amount of ZSM-48 type material; 0.1 to 7.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 6.

[0063] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to aluminum oxide (Al2O3) of 80 to 200; at least 70% polytype 6 of the total amount of ZSM-48 type material; 0.1 to 4.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 6.

[0064] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to alumina (Al2O3) of 80 to 200; at least 70% polytype 6 of the total amount of ZSM-48 type material; 0.1 to 4.0 wt.% EU-1; ​​wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 6.

[0065] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to alumina (Al2O3) of 80 to 200; at least 70% polytype 6 of the total amount of ZSM-48 type material; 0.1 to 4.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 6

[0066] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to aluminum oxide (Al2O3) of 80 to 160; at least 70% polytype 6 of the total amount of ZSM-48 type material; 0.1 to 4.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 6.

[0067] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to alumina (Al2O3) of 70 to 160; at least 70% polytype 6 of the total amount of ZSM-48 type material; from 0.1 to 4.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 6.

[0068] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to aluminum oxide (Al2O3) of 70 to 200; at least 80% polytype 6 of the total amount of ZSM-48 type material; from 0.1 to 4.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 6.

[0069] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to aluminum oxide (Al2O3) of 80 to 200; at least 80% polytype 6 of the total amount of ZSM-48 type material; 0.1 to 4.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 6.

[0070] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to aluminum oxide (Al2O3) of 80 to 200; at least 80% polytype 6 of the total amount of ZSM-48 type material; 0.1 to 7.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 4.

[0071] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to aluminum oxide (Al2O3) of 80 to 200; at least 80% polytype 6 of the total amount of ZSM-48 type material; 0.1 to 4.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 4.

[0072] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to alumina (Al2O3) of 80 to 160; at least 80% polytype 6 of the total amount of ZSM-48 type material; 0.1 to 4.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 4.

[0073] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to aluminum oxide (Al2O3) of 100 to 140; at least 80% polytype 6 of the total amount of ZSM-48 type material; 0.1 to 4.0 wt.% of a molecular sieve phase of the EUO type; wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 4.

[0074] In embodiments, the SSZ-91 zeolite has: a molar ratio (SAR) of silica (SiO2) to alumina (Al2O3) of 100 to 140; at least 80% polytype 6 of the total amount of the ZSM-48 type material; 0.1 to 4.0 wt.% EU-1; ​​wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of 1 to 4.

[0075] The zeolite SSZ-91 synthesized as described herein can be characterized by its X-ray diffraction pattern. The powder X-ray diffraction lines shown in Table 1 are representative of the as-synthesized zeolite SSZ-91. Minor changes in the X-ray diffraction pattern may result from changes in the molar ratios of framework species of a particular sample due to changes in lattice constants. In addition, sufficiently small crystals affect the shape and intensity of the peaks, resulting in significant peak broadening. Minor changes in the X-ray diffraction pattern may also result from changes in the organic compound used in the preparation and changes in the Si / Al molar ratio from sample to sample. Calcination may also cause minor shifts in the X-ray diffraction pattern. Despite these minor changes, the basic structure of the crystal lattice remains unchanged. TABLE 1 Characteristic peaks for as-synthesized SSZ-91 2-theta(a) Interplanar distance d (nm) Relative intensity(b) 7,55 1,170 W 8,71 1,015 W 12,49 0,708 W 15,12 0,586 W 21,18 0,419 VS 22,82 0,390 VS 24,62 0,361 W 26,39 0,337 W 29,03 0,307 W 31,33 0,285 W (a) ±0.20 (b) The powder diffraction patterns presented are based on a relative intensity scale in which the strongest line in the X-ray diffraction pattern is assigned a value of 100: W=weak (>0 to ≤20); M=medium (>20 to ≤40); S=strong (>40 to ≤60); VS=very strong (>60 to ≤100).

[0076] The X-ray diffraction pattern lines shown in Table 2 are characteristic of calcined SSZ-91.TABLE 2Characteristic peaks of calcined SSZ-91 2-theta(a) Interplanar distance d (nm) Relative intensity(b) 7,67 1,152 M 8,81 1,003 W 12,61 0,701 W 15,30 0,579 W 21,25 0,418 VS 23,02 0,386 VS 24,91 0,357 W 26,63 0,334 W 29,20 0,306 W 31,51 0,284 W (a) ±0.20 (b)The powder diffraction patterns presented are based on a relative intensity scale in which the strongest line in the X-ray diffraction pattern is assigned a value of 100: W=weak (>0 to ≤20); M=medium (>20 to ≤40); S=strong (>40 to ≤60); VS=very strong (>60 to ≤100).

[0077] The powder X-ray diffraction patterns presented in this paper were obtained by standard methods. CuK radiation was used as the radiation. α The height and position of the peaks as a function of 2θ, where θ is the Bragg angle, were determined from the relative intensities of the peaks (corrected for the background), after which d, the interplanar distance corresponding to the recorded lines, could be calculated. Preparation of zeolite SSZ-91 Reaction mixture and crystallization

[0078] In the production of zeolite SSZ-91, at least one organic compound selective for the synthesis of molecular sieves of the ZSM-48 zeolite family is used as a structure directing agent (SDA), also known as a crystallization matrix. SDA, useful for the production of zeolite SSZ-91, is represented by the following structure (1): (1)N, N,N, N′,N′,N′-hexamethylhexamethylenediammonium or hexamethonium cation.

[0079] The SDA cation is typically associated with anions, which can be any anions that are not detrimental to the formation of the molecular sieve. Representative examples of anions include hydroxide, acetate, sulfate, carboxylate, and halogens such as fluoride, chloride, bromide, and iodide. In one embodiment, the anion is bromide.

[0080] In general, the SSZ-91 zeolite is prepared by: (a) providing a reaction mixture comprising (1) at least one source of silica; (2) at least one source of aluminum oxide; (3) at least one source of an element selected from Groups 1 and 2 of the periodic table; (4) hydroxide ions; (5) hexamethonium cations; and (6) water; and (b) maintaining the reaction mixture under crystallization conditions sufficient to form molecular sieve crystals.

[0081] The composition of the reaction mixture from which zeolite SSZ-91 is formed, in molar ratios, is given below: Components Molar ratio SiO2 / Al2O3 50-220 M / SiO2 0,05-1,0 Q / SiO2 0,01-0,2 OH / SiO2 0,05-0,4 H2O / SiO2 3-100 where M is selected from the group consisting of elements from groups 1 and 2 of the periodic table; and Q is the structure-forming agent represented by structure 1 above.

[0082] In embodiments, the composition of the reaction mixture from which the SSZ-91 zeolite is formed is given below in molar ratios: Components Molar ratio SiO2 / Al2O3 85-180 M / SiO2 0,1-0,8 Q / SiO2 0,02-0,1 OH / SiO2 0,10-0,3 H2O / SiO2 10-50 where M is selected from the group consisting of elements from groups 1 and 2 of the periodic table; and Q is the structure-forming agent represented by structure 1 above.

[0083] In embodiments, the composition of the reaction mixture from which the SSZ-91 zeolite is formed is given below in molar ratios: Components Molar ratio SiO2 / Al2O3 50-220 M / SiO2 0,05-1,0 Q / SiO2 0,01-0,2 OH / SiO2 0,05-0,4 H2O / SiO2 3-100 where M is selected from the group consisting of elements from groups 1 and 2 of the periodic table; and Q is the structure-forming agent represented by structure 1 above.

[0084] In embodiments, the composition of the reaction mixture from which the SSZ-91 zeolite is formed is given below in molar ratios: Components Molar ratio SiO2 / Al2O3 50-220 M / SiO2 0,05-1,0 Q / SiO2 0,02-0,1 OH / SiO2 0,05-0,4 H2O / SiO2 3-100 where M is selected from the group consisting of elements from groups 1 and 2 of the periodic table; and Q is the structure-forming agent represented by structure 1 above.

[0085] In embodiments, the composition of the reaction mixture from which the SSZ-91 zeolite is formed is given below in molar ratios: Components Molar ratio SiO2 / Al2O3 80-180 M / SiO2 0,05-1,0 Q / SiO2 0,02-0,1 OH / SiO2 0,05-0,4 H2O / SiO2 3-100 where M is selected from the group consisting of elements from groups 1 and 2 of the periodic table; and Q is the structure-forming agent represented by structure 1 above.

[0086] In embodiments, the composition of the reaction mixture from which the SSZ-91 zeolite is formed is given below in molar ratios: Components Molar ratio SiO2 / Al2O3 80-160 M / SiO2 0,05-1,0 Q / SiO2 0,02-0,1 OH / SiO2 0,1-0,4 H2O / SiO2 3-100 where M is selected from the group consisting of elements from groups 1 and 2 of the periodic table; and Q is the structure-forming agent represented by structure 1 above.

[0087] Silicon sources useful in this application include fumed silica, precipitated silica, silica hydrogel, silicic acid, colloidal silica, tetraalkyl orthosilicates (e.g., tetraethyl orthosilicate), and silica hydroxides.

[0088] A reaction mixture can be formed containing at least one source of elements selected from Groups 1 and 2 of the periodic table (referred to herein as M). In embodiments, the reaction mixture is formed using a source of an element from Group 1 of the periodic table. In embodiments, the reaction mixture is formed using a source of sodium (Na). Any M-containing compound that does not interfere with the crystallization process is suitable. Sources of such Group 1 and 2 elements include oxide, hydroxides, nitrates, sulfates, halides, oxalates, citrates, and their acetates.

[0089] In each embodiment described herein, the reaction mixture for the molecular sieve may be supplied from more than one source. Furthermore, two or more reaction components may be provided by a single source.

[0090] The reaction mixture is maintained at elevated temperature until molecular sieve crystals are formed. The hydrothermal crystallization of the zeolite is typically carried out under pressure, typically in an autoclave, such that the reaction mixture is subjected to autogenous pressure and, optionally, stirring, at a temperature in the range of from about 125°C to about 200°C, for a suitable period of time, such as from about an hour to several days, such as from about 1 hour to about 10 days, from about 1 hour to about 9 days, from about 1 hour to about 8 days, from about 1 hour to about 7 days, or from about 1 hour to about 6 days, or from about 1 hour to about 5 days, or from about 1 hour to about 4 days, or from about 1 hour to about 3 days, or from about 1 hour to about 48 hours, or from about 1 hour to about 36 hours, or from about 1 hour to about 24 hours, or from about 1 hour to about 18 hours.

[0091] In embodiments, the SSZ-91 zeolite is produced by a method comprising providing a reaction mixture comprising at least one source of silicon, at least one source of aluminum, at least one source of an element selected from Groups 1 and 2 of the periodic table, hydroxide ions, hexamethonium cations and water; and subjecting the reaction mixture to crystallization conditions; wherein the reaction mixture comprises: Components Molar ratio SiO2 / Al2O3 50-220 M / SiO2 0,05-1,0 Q / SiO2 0,01-0,2 OH / SiO2 0,05-0,4 H2O / SiO2 3-100 where M is selected from the group consisting of elements from groups 1 and 2 of the periodic table; Q is a hexamethonium cation, and where the crystallization conditions comprise maintaining the reaction mixture at an elevated temperature in the range of from about 125°C to about 200°C.

[0092] In embodiments, the SSZ-91 zeolite is produced by a method comprising providing a reaction mixture comprising at least one source of silicon, at least one source of aluminum, at least one source of an element selected from Groups 1 and 2 of the periodic table, hydroxide ions, hexamethonium cations and water; and subjecting the reaction mixture to crystallization conditions; wherein the reaction mixture comprises: Components Molar ratio SiO2 / Al2O3 50-220 M / SiO2 0,05-1,0 Q / SiO2 0,02-0,1 OH / SiO2 0,05-0,4 H2O / SiO2 3-100 where M is selected from the group consisting of elements from groups 1 and 2 of the periodic table; Q is a hexamethonium cation, and where the crystallization conditions comprise maintaining the reaction mixture at an elevated temperature in the range from about 125°C to about 200°C, such as from about 125°C to about 180°C, or from about 125°C to about 160°C.

[0093] In embodiments, the SSZ-91 zeolite is produced by a method comprising providing a reaction mixture comprising at least one source of silicon, at least one source of aluminum, at least one source of an element selected from Groups 1 and 2 of the periodic table, hydroxide ions, hexamethonium cations and water; and subjecting the reaction mixture to crystallization conditions; wherein the reaction mixture comprises: Components Molar ratio SiO2 / Al2O3 80-180 M / SiO2 0,05-1,0 Q / SiO2 0,05-0,2 OH / SiO2 0,05-0,4 H2O / SiO2 3-100 where M is selected from the group consisting of elements from groups 1 and 2 of the periodic table; Q is a hexamethonium cation, and where the crystallization conditions comprise maintaining the reaction mixture at an elevated temperature in the range from about 125°C to about 200°C, such as from about 125°C to about 180°C, or from about 125°C to about 160°C.

[0094] In embodiments, the SSZ-91 zeolite is produced by a method comprising providing a reaction mixture comprising at least one source of silicon, at least one source of aluminum, at least one source of an element selected from Groups 1 and 2 of the periodic table, hydroxide ions, hexamethonium cations and water; and subjecting the reaction mixture to crystallization conditions; wherein the reaction mixture comprises: Components Molar ratio SiO2 / Al2O3 80-160 M / SiO2 0,05-1,0 Q / SiO2 0,02-0,1 OH / SiO2 0,1-0,4 H2O / SiO2 3-100 where M is selected from the group consisting of elements from groups 1 and 2 of the periodic table; Q is a hexamethonium cation, and where the crystallization conditions comprise maintaining the reaction mixture at an elevated temperature in the range from about 125°C to about 200°C, such as from about 125°C to about 180°C, or from about 125°C to about 160°C.

[0095] In embodiments, the crystallization conditions include maintaining the reaction mixture at an elevated temperature in the range of about 125°C to about 200°C, such as about 125°C to about 180°C, about 125°C to about 180°C, about 125°C to about 170°C, about 125°C to about 160°C.

[0096] The formation of the EUO phase is suppressed by selecting the hydrogel composition, crystallization temperature, and crystallization time that reduce (or minimize) the formation of the EUO phase while increasing (or maximizing) the yield of the SSZ-91 product. The examples given in US-A-9920260 provide an understanding of how changes in these process variables minimize the formation of EU-1. A zeolite manufacturer skilled in the art can easily select the process variables necessary to minimize the formation of EU-1, since these variables will depend on the size of the production run, the capabilities of the available equipment, the desired target yield, and the acceptable level of EU-1 material in the product.

[0097] During the hydrothermal crystallization step, molecular sieve crystals can be allowed to spontaneously form from the reaction mixture. Using molecular sieve crystals as seeds can be advantageous in reducing the time required for complete crystallization. Furthermore, seeding can improve the purity of the resulting product by promoting nucleation and / or formation of the molecular sieve over any undesirable phases. However, it has been found that when using seeds, the seed material must be very phase-pure SSZ-91 to avoid the formation of large amounts of the EUO phase. When used as seeds, seed crystals are added in an amount of 0.5% to 5% of the weight of the silicon source used in the reaction mixture.

[0098] The formation of magadiite and kenyaite is minimized by optimizing the hexamethonium bromide / SiO2 ratio, controlling the hydroxide concentration, and minimizing the sodium concentration, since magadiite and kenyaite are layered sodium silicate composites. Examples given in US-A-9920260 provide insight into how varying gelation conditions minimizes EU-1 formation.

[0099] After the formation of the molecular sieve crystals, the solid product is separated from the reaction mixture by standard mechanical separation methods, such as filtration. The crystals are washed with water and then dried to obtain the synthesized molecular sieve crystals. The drying step can be carried out at atmospheric pressure or under vacuum. Post-crystallization Treatment

[00100] Zeolite SSZ-91 can be used in its as-synthesized form, but is usually subjected to heat treatment (calcination). The term “as-synthesized” refers to zeolite SSZ-91 in its form after crystallization, before the SDA cation is removed. SDA can be removed by heat treatment (e.g., calcination), for example, in an oxidizing atmosphere (e.g., air, a gas with an oxygen partial pressure of greater than 0 kPa) at a temperature, easily determined by one skilled in the art, sufficient to remove SDA from the molecular sieve.SDA can also be removed by ozonation and photolysis techniques (e.g., exposing an SDA-containing molecular sieve product to light or electromagnetic radiation of a wavelength shorter than visible light under conditions sufficient to selectively remove the organic compound from the molecular sieve), as described in U.S. Patent No. 6,960,327.

[00101] The SSZ-91 zeolite can subsequently be calcined in steam, air, or an inert gas at a temperature of from 200°C to 800°C for a period of time from 1 hour to several days, such as from 1 to 48 hours. It is generally desirable to remove an extralattice cation (e.g., Na. +) by ion exchange and replace it with hydrogen, ammonium, or any desired metal ion.

[00102] If the formed molecular sieve is an intermediate molecular sieve, the target molecular sieve (e.g., zeolite SSZ-91) can be obtained by post-synthesis methods such as lattice heteroatom replacement methods. The target molecular sieve (e.g., zeolite SSZ-91) can also be obtained by removing heteroatoms from the lattice by known methods such as acid leaching.

[00103] The zeolite SSZ-91 made by the process disclosed herein can be provided in a wide variety of physical forms. Zeolite SSZ-91 may be in the form of a powder, granules, or a molded product such as an extrudate having a particle size sufficient to pass through a 2-mesh Tyler sieve and be retained on a 400-mesh Tyler sieve.In cases where the catalyst is formed, for example, by extrusion with an organic binder, the SSZ-91 zeolite may be extruded before drying, or dried, or partially dried, and then extruded.

[00104] The SSZ-91 zeolite may be mixed with other materials that are stable at the temperatures and other conditions used in organic conversion processes. Such matrix materials include active and inactive materials and synthetic or naturally occurring molecular sieves, as well as inorganic materials such as clays, silica, and metal oxides. Examples of such materials and methods for their possible use are disclosed in U.S. Pat. Nos. 4,910,006 and 5,316,753.SSZ-32

[00105] SSZ-32 zeolites are described in US-A-5,397,454, which is incorporated herein by reference in its entirety. SSZ-32 zeolites may also be referred to as MTT framework molecular sieves.

[00106] The SSZ-32 zeolite (also described as SSZ-32 molecular sieves) has a silica (SiO2) to alumina (Al2O3) mole ratio (SAR) in the range of 20 to less than 40, such as in the range of 20-39, 20-38, 20-37, 25-39, 25-38, 25-37, 25-35 or 30-35, and a crystal size in the range of about 0.1 to about 0.4 μm. In embodiments, the SSZ-32 zeolite (also described as SSZ-32 molecular sieves) has a silica (SiO2) to alumina (Al2O3) mole ratio (SAR) in the range of 25-37.

[00107] In embodiments, the SSZ-32 zeolite has a silica (SiO2) to alumina (Al2O3) molar ratio (SAR) in the range of 25 to less than 40, such as 25 to 35, and has a crystal size in the range of about 0.1 to about 0.4 μm.

[00108] In embodiments, the SSZ-32 zeolite has a crystal size in the range of about 0.1 to about 0.4 μm, about 0.1 to about 0.3 μm, or about 0.15 to about 0.25 μm.The crystal size can be measured by transmission electron microscopy (TEM) and refers to the largest dimension of the crystal.

[00109] In embodiments, the composition of the SSZ-32 zeolite in the as-synthesized and anhydrous state, in terms of the molar ratios of the oxides, is as follows: (0.05-2.0)Q2O:(0.1-2.0)M2O:Al2O3:(20 to less than 40)SiO2, where M is an alkali metal cation and Q is an N-lower alkyl-N'-isopropyl-imidazolium cation (e.g., N,N'-diisopropyl-imidazolium cation or N-methyl-N'-isopropyl-imidazolium cation).

[00110] In embodiments, the as-synthesized SSZ-32 zeolite has a crystalline structure, the X-ray powder diffraction pattern of which shows the following characteristic lines:. d / n Int.I / Io 11,05 10,05 7,83 4,545 26 10 17 71 4,277 71 3,915 100 3,726 98

[00111] X-ray powder diffraction patterns were determined using standard techniques. K-alpha / copper doublet radiation was used, and a spectrometer with a scintillation counter and a strip chart recorder was used. The heights of the I peaks and their positions as a function of 2Θ, where Θ is the Bragg angle, were read from the spectrometer chart. From these measured values, the relative intensity, 100I / I, can be calculated. o , where I o- the intensity of the strongest line or peak, and d is the interplanar spacing in angstroms corresponding to the recorded lines. The X-ray diffraction pattern shown above is characteristic of the new SSZ-32 zeolites. Zeolite prepared by exchanging a metal cation or other cations present in the zeolite for various other cations yields virtually the same diffraction pattern, although minor shifts in the interplanar spacing and slight changes in the relative intensity may be observed. Minor changes in the diffraction pattern may also result from variations in the organic compound used in preparation and changes in the silica-to-alumina molar ratio in different samples. Calcination may also cause minor shifts in the X-ray diffraction pattern. Despite these minor changes, the basic structure of the crystal lattice remains unchanged.Preparation of SSZ-32

[00112] SSZ-32 zeolites can be prepared as described in U.S. Pat. No. 5,397,454. SSZ-32 zeolites can be prepared from an aqueous solution containing sources of an alkali metal oxide, an N-lower alkyl-N'-isopropyl-imidazolium cation (e.g., N,N'-diisopropyl-imidazolium cation or N-methyl-N'-isopropyl-imidazolium cation), alumina (e.g., when the alumina source provides alumina that is in covalently dispersed form on silica), and silicon oxide. In embodiments, the reaction mixture has a composition in molar ratios falling within the following ranges: Components Molar ratio SiO2 / Al2O3 20 - less than 40 OH- / SiO2 0,1-1,0 Q / SiO2 0,05-0,50 M+ / SiO2 0,05-0,30 H2O / SiO2 Q / Q+M+ 20-300 0,25-0,75 where Q is an N-lower alkyl-N'-isopropyl-imidazolium cation (e.g., N,N'-diisopropyl-imidazolium cation or N-methyl-N'-isopropyl-imidazolium cation). M is an alkali metal ion (e.g., sodium or potassium). The organic cationic compound serving as the source of the quaternary ammonium ion employed can provide hydroxide ion.

[00113] In embodiments, the reaction mixture has a composition in molar ratios falling within the following ranges: Components Molar ratio SiO2 / Al2O3 30-35 OH- / SiO2 0,20-0,40 Q / SiO2 0,15-0,30 M+ / SiO2 0,15-0,30 H2O / SiO2 Q / Q+M+ 25-60 0,33-0,67 where Q is an N-lower alkyl-N'-isopropyl-imidazolium cation (e.g., N,N'-diisopropyl-imidazolium cation or N-methyl-N'-isopropyl-imidazolium cation). M is an alkali metal ion (e.g., sodium or potassium). The organic cationic compound serving as the source of the quaternary ammonium ion used can provide hydroxide ion.

[00114] Sources of alumina for the reaction mixture include aluminates, alumina, and aluminum compounds such as aluminum-coated silica colloids, Al2(SO4)3, and other zeolites. In embodiments, zeolites with a pentasil structure and lower SiO2 / Al2O3 ratios (approximately 10), such as mordenite and ferrierite zeolites, can be used as sources of alumina.

[00115] Sources of silicon oxide include silicates, silica hydrogel, silicic acid, colloidal silica, fumed silicas, tetraalkyl orthosilicates, and silica hydroxides.

[00116] The reaction mixture is maintained at an elevated temperature until zeolite crystals are formed. Temperatures in the hydrothermal crystallization step can be maintained in the range of from about 140°C to about 200°C, for example from about 160°C to about 180°C, or from about 170°C to about 180°C. The crystallization period can be more than 1 day, for example from about 5 days to about 10 days.

[00117] The hydrothermal crystallization is carried out under pressure and usually in an autoclave, so that the reaction mixture is subjected to autogenous pressure. The reaction mixture can be stirred during crystallization. During the hydrothermal crystallization step, crystals can be allowed to spontaneously form from the reaction mixture. The reaction mixture may also be seeded with SSZ-32 or ZSM-23 crystals to both direct and accelerate crystallization and to minimize the formation of undesirable aluminosilicate contaminants.If the reaction mixture is seeded with crystals, the concentration of the organic compound (e.g., alcohol) can be reduced.

[00118] After the zeolite crystals have formed, the solid product is separated from the reaction mixture by standard mechanical separation methods, such as filtration or centrifugation. The crystals are washed with water and then dried, for example, at a temperature of from 90°C to 150°C for from 8 to 24 hours, to obtain the synthesized crystals of zeolite SSZ-32x. The drying step can be carried out at atmospheric or subatmospheric pressure.

[00119] Zeolite SSZ-32 can be used as synthesized or can be thermally treated (calcined) as described above for zeolite SSZ-91. It is generally desirable to remove the alkali metal cation by ion exchange and replace it with hydrogen, ammonium, or any desired metal ion.SSZ-32x

[00120] Zeolite SSZ-32x is described in US 7,468,126, which is incorporated herein by reference in its entirety.SSZ-32 zeolites may also be referred to as MTT-type framework molecular sieves.

[00121] SSZ-32x zeolite (also described as SSZ-32x molecular sieve) has a silica (SiO2) to alumina (Al2O3) mole ratio (SAR) in the range of 20 to less than 40 and a crystal size in the range of about 50 to about 500 angstroms. In embodiments, the SSZ-32x zeolite has a silica (SiO2) to alumina (Al2O3) mole ratio (SAR) in the range of 20-39, 20-38, 20-37, 25-39, 25-38, 30-37, 30-35, or 25-35. In embodiments, the SSZ-32x zeolite (also described as SSZ-32x molecular sieves) has a silica (SiO2) to alumina (Al2O3) molar ratio (SAR) in the range of 30-35.

[00122] In embodiments, the SSZ-32x zeolite has a crystal size in the range of about 50 to about 500 angstroms, about 100 to about 500 angstroms, about 100 to about 400 angstroms, or about 200 to about 400 angstroms.Crystal size can be measured using transmission electron microscopy (TEM) and refers to the largest dimension of the crystal.

[00123] In embodiments, the SSZ-32x zeolite has a silica (SiO2) to alumina (Al2O3) molar ratio (SAR) in the range of 30-35 and has a crystal size in the range of about 200 to about 400 angstroms.

[00124] As determined by TEM studies, the SSZ-32x crystallites have an elongated shape. In embodiments, the SSZ-32x crystallites have an aspect ratio in the range of about 2.0 to about 2.4.

[00125] In embodiments, the as-synthesized SSZ-32x zeolite has a crystalline structure whose X-ray powder diffraction pattern exhibits the following characteristic lines: 2Θ Interplanar distance (Å) Intensity Relative intensity (%) (I / Io X 100) 8,00 11,05 15 26 8,80 10,05 6 10 11,30 7,83 10 17 14,50 6,11 1 2 15,75 5,63 3 5 16,50 5,37 3 5 18,10 4,901 7 12 19,53 4,545 41 71 20,05 4,428 6, shoulder 10, shoulder 20,77 4,277 41 71 21,30 4,171 7 12 22,71 3,915 58 100 23,88 3,726 57 98 24,57 3,623 30 52 25,08 3,551 25 43 25,88 3,443 27 47 26,88 3,317 5 9 28,11 3,174 6 10 Preparation of zeolite SSZ-32x

[00126] Zeolites SSZ-32x can be prepared as described in U.S. Pat. No. 7,468,126. Zeolites SSZ-32x can be prepared from an aqueous solution containing sources of an alkali metal oxide, N-lower alkyl-N'-isopropyl-imidazolium cation (e.g., N,N'-diisopropyl-imidazolium cation or N-methyl-N'-isopropyl-imidazolium cation), alumina (e.g., when the source of alumina provides alumina that is in covalently dispersed form on silica) and silicon oxide. In embodiments, the reaction mixture has a composition in molar ratios falling within the following ranges: Components Molar ratio SiO2 / Al2O3 20 - less than 40 OH- / SiO2 0,1-1,0 Q / SiO2 0,05-0,50 M+ / SiO2 0,05-0,30 H2O / SiO2 Q / Q+M+ 20-300 0,25-0,75 where Q is the sum of Q a and Q b , Q ais an N-lower alkyl-N'-isopropyl-imidazolium cation (e.g., N,N'-diisopropyl-imidazolium cation or N-methyl-N'-isopropyl-imidazolium cation). Q b is an amine. Suitable examples are Q b are isobutyl, neopentyl, or monoethylamine, although other amines can be used. The molar concentration of the amine, Q b , must be greater than the molar concentration of the imidazole compound, Q a In embodiments, the molar concentration Q b is in the range from 2 to a value nine times greater than the molar concentration Q a . M is an alkali metal ion (e.g., sodium or potassium). The organic cationic compound serving as the source of the quaternary ammonium ion employed can provide a hydroxide ion.

[00127] In embodiments, the reaction mixture has a composition in molar ratios falling within the following ranges: Components Molar ratio SiO2 / Al2O3 30-35 OH- / SiO2 0,20-0,40 Q / SiO2 0,15-0,30 M+ / SiO2 0,15-0,30 H2O / SiO2 Q / Q+M+ 25-60 0,33-0,67 where Q is the sum of Q a and Q b , Q a is an N-lower alkyl-N'-isopropyl-imidazolium cation (e.g., N,N'-diisopropyl-imidazolium cation or N-methyl-N'-isopropyl-imidazolium cation). Q b is an amine. Suitable examples are Q b are isobutyl, neopentyl, or monoethylamine, although other amines can be used. The molar concentration of the amine, Q b , must be greater than the molar concentration of the imidazole compound, Q a In embodiments, the molar concentration Q b is in the range from 2 to a value nine times greater than the molar concentration Q a. M is an alkali metal ion (e.g., sodium or potassium). The organic cationic compound serving as the source of the quaternary ammonium ion used can provide the hydroxide ion.

[00128] Sources of aluminum oxide for the reaction mixture include aluminates, alumina, and aluminum compounds such as aluminum-coated silica colloids, Al2(SO4)3, and other zeolites. In embodiments, zeolites with a pentasil structure and lower SiO2 / Al2O3 ratios (approximately 10), such as mordenite and ferrierite zeolites, can be used as sources of aluminum oxide.

[00129] Sources of silicon oxide include silicates, silica hydrogel, silicic acid, colloidal silica, fumed silicas, tetraalkyl orthosilicates, and silica hydroxides.

[00130] The reaction mixture is maintained at an elevated temperature until zeolite crystals are formed.Temperatures during the hydrothermal crystallization step may be maintained in the range of about 140°C to about 200°C, such as about 160°C to about 180°C, or about 170°C to about 180°C. The crystallization period may be longer than 1 day, such as about 5 days to about 10 days.

[00131] The hydrothermal crystallization is carried out under pressure and typically in an autoclave so that the reaction mixture is subjected to autogenous pressure. The reaction mixture may be stirred during the addition of the components and during crystallization. During the hydrothermal crystallization step, crystals may be allowed to spontaneously form from the reaction mixture. The reaction mixture may also be seeded with SSZ-32 crystals both to direct and accelerate crystallization and to minimize the formation of undesirable aluminosilicate impurities.

[00132] After the formation of the zeolite crystals, the solid product is separated from the reaction mixture using standard mechanical separation methods, such as filtration or centrifugation. The crystals are washed with water and then dried, for example, at a temperature of from 90°C to 150°C for from 8 to 24 hours, to obtain the synthesized crystals of zeolite SSZ-32x. The drying step can be carried out at atmospheric or subatmospheric pressure.

[00133] Zeolite SSZ-32x can be used in the synthesized form or can be thermally treated (calcined) as described above for zeolite SSZ-91. It is generally desirable to remove the alkali metal cation by ion exchange and replace it with hydrogen, ammonium, or any desired metal ion. Preparation of the hydroisomerization catalyst

[00134] The hydroisomerization catalyst comprises zeolite SSZ-91, zeolite SSZ-32, or zeolite SSZ-32x. The zeolite SSZ-91, zeolite SSZ-32, or zeolite SSZ-32x may be in as-synthesized or calcined form.

[00135] In embodiments, the hydroisomerization catalyst is formed from zeolite SSZ-91, zeolite SSZ-32, or zeolite SSZ-32x in calcined form.

[00136] In embodiments, the hydroisomerization catalyst comprises: a molecular sieve selected from zeolite SSZ-91, zeolite SSZ-32, or zeolite SSZ-32x; and a group 2, 8, 9, or 10 metal (e.g., a group 8-10 metal such as Pt).

[00137] In embodiments, the hydroisomerization catalyst is formed by mixing a molecular sieve selected from zeolite SSZ-91, zeolite SSZ-32, and zeolite SSZ-32x (in as-synthesized or calcined form) with an oxide binder such as alumina.In embodiments, mixing a molecular sieve selected from zeolite SSZ-91, zeolite SSZ-32, and zeolite SSZ-32x (in as-synthesized or calcined form) with an oxide binder comprises mixing the molecular sieve selected from zeolite SSZ-91, zeolite SSZ-32, or zeolite SSZ-32x (in as-synthesized or calcined form) with an oxide binder and extruding the product. The mixture of the molecular sieve and the oxide binder can be formed into a particle or extrudate having a wide range of physical shapes and sizes. In embodiments, the extrudate or particle can be dried and calcined prior to loading with metal. In embodiments, the extrudate or particle is impregnated with a metal, such as a Group 2, 8, 9, or 10 metal (e.g., a Group 8-10 metal such as Pt), and then dried and calcined. In embodiments, the extrudate or particle is dried and calcined prior to loading with the metal.

[00138] In embodiments, a hydroisomerization catalyst is prepared by: mixing a molecular sieve (selected from zeolite SSZ-91, zeolite SSZ-32, and zeolite SSZ-32x) with an oxide binder to form an extrudate matrix; impregnating the extrudate matrix with an impregnation solution containing a metal, such as a Group 2, 8, 9, or 10 metal (e.g., a Group 8-10 metal such as Pt), to form a metal-loaded extrudate; drying the metal-loaded extrudate; and calcining the dried metal-loaded extrudate.

[00139] In embodiments, the hydroisomerization catalyst is formed by impregnating a molecular sieve selected from zeolite SSZ-91, zeolite SSZ-32, and zeolite SSZ-32x with a solution containing a metal, such as a Group 2, 8, 9, or 10 metal (e.g., a Group 8-10 metal such as Pt).In embodiments, the hydroisomerization catalyst is formed by impregnating a molecular sieve (selected from zeolite SSZ-91, zeolite SSZ-32, and zeolite SSZ-32x) in calcined form with a solution containing a Group 2, 8, 9, or 10 metal (e.g., a Group 8-10 metal such as Pt). In embodiments, the hydroisomerization catalyst is formed by impregnating an extrudate matrix containing a molecular sieve (selected from zeolite SSZ-91, zeolite SSZ-32, and zeolite SSZ-32x) and an oxide binder.

[00140] In embodiments, the extrudate base is exposed to (e.g., impregnated with) an impregnation solution containing a metal (e.g., a Group 2, 8, 9, or 10 metal (e.g., a Group 8-10 metal such as Pt)) for 0.1 to 10 hours.

[00141] In embodiments, the extrudate base is dried (e.g., at a temperature in the range of about 100 °F (38 °C) to about 300 °F (149 °C) for about 0.1 to about 10 hours) and calcined (at a temperature in the range of about 390 °F (199 °C) to about 1200 °F (649 °C) or about 600 °F (316 °C) to about 1200 °F (649 °C) for about 0.1 to about 10 hours) prior to impregnation.

[00142] In some embodiments, an extrudate base formed by mixing a molecular sieve (selected from zeolite SSZ-91, zeolite SSZ-32, and zeolite SSZ-32x) and an oxide binder is dried and calcined prior to impregnation. In embodiments, the dried and calcined extrudate base is impregnated with an impregnation solution to form a metal-loaded extrudate before being dried and calcined again to form a hydroisomerization catalyst.

[00143] In embodiments, the impregnated extrudate base containing the SSZ-91 zeolite is dried at a temperature in the range of about 100 °F (38 °C) to about 300 °F (149 °C) for about 0.1 to about 10 hours.

[00144] In embodiments, the dried metal-loaded extrudate is calcined at a temperature in the range of about 600 °F (316 °C) to about 1200 °F (649 °C) for about 0.1 to about 10 hours. In embodiments, the calcining occurs in air. METHOD FOR HYDROISOMERIZING A DIESEL FUEL FEED

[00145] A method for hydroisomerizing a diesel fuel feedstock includes contacting the diesel fuel feedstock with a hydroisomerization catalyst. In embodiments, the hydroisomerization of the diesel fuel feedstock occurs in the presence of hydrogen.

[00146] In one embodiment, as shown in FIG.1, diesel fuel feedstock 10 is fed to hydroisomerization reactor 14 along with hydrogen 12, wherein hydroisomerization reactor 14 contains hydroisomerization catalyst 16. In reactor 14, diesel fuel feedstock 10 is contacted with hydroisomerization catalyst 16 under hydroisomerization conditions in the presence of hydrogen to produce a hydroisomerized stream 18.

[00147] In embodiments, hydroisomerization catalyst 16 is activated prior to introducing diesel fuel feedstock into hydroisomerization reactor 14. In embodiments, activating the catalyst comprises reduction at a temperature of 450 to 650 °F (232 to 343 °C) for 1 to 10 hours, such as at a temperature of 500 °F (260 °C) for 2 hours.

[00148] In embodiments, the hydroisomerization catalyst is a layered catalyst.In embodiments, the hydroisomerization catalyst comprises a first layer comprising a first hydroisomerization catalyst and a second layer comprising a second hydroisomerization catalyst.

[00149] In embodiments, the first or second hydroisomerization catalyst comprises SSZ-91 zeolite as described herein, wherein the first and second hydroisomerization catalysts are mutually exclusive. In embodiments, the first and second hydroisomerization catalysts independently comprise SSZ-91 zeolite and a Columns 8-10 metal.

[00150] In embodiments, the first or second hydroisomerization catalyst comprises SSZ-32 zeolite as described herein, wherein the first and second hydroisomerization catalysts are mutually exclusive. In embodiments, the first and second hydroisomerization catalysts independently comprise SSZ-32 zeolite and a Columns 8-10 metal.

[00151] In embodiments, the first or second hydroisomerization catalyst comprises an SSZ-32x zeolite as described herein, wherein the first and second hydroisomerization catalysts are mutually exclusive. In embodiments, the first and second hydroisomerization catalysts independently comprise an SSZ-32x zeolite and a Column 8-10 metal.

[00152] In embodiments, the first or second hydroisomerization catalyst comprises an SSZ-32 zeolite or an SSZ-32x zeolite as described herein, wherein the first and second hydroisomerization catalysts independently comprise an SSZ-32 zeolite or an SSZ-32x zeolite and a Column 8-10 metal.

[00153] In the embodiment shown in Fig. 2, diesel fuel feedstock 10 is fed to hydroisomerization reactor 14 along with hydrogen 12.The hydroisomerization reactor 14 comprises a layered hydroisomerization catalyst comprising a first hydroisomerization catalyst 16a and a second hydroisomerization catalyst 16b, wherein the first hydroisomerization catalyst 16a is located upstream of the second hydroisomerization catalyst 16b. In the embodiment shown in Fig. 2, the diesel fuel feedstock is contacted with the first hydroisomerization catalyst 16a in the first hydroisomerization zone 14a of the hydroisomerization reactor 14 in the presence of hydrogen before being contacted with the second hydroisomerization catalyst 16b in the presence of hydrogen in the second hydroisomerization zone 14b.

[00154] In embodiments, the hydroisomerization conditions (e.g., the hydroisomerization conditions in reactor 14) include a temperature in the range of about 390 °F to about 800 °F (199 °C to 427 °C), such as about 550 °F to about 700 °F (288 °C to 371 °C).

[00155] In embodiments, the hydroisomerization conditions (e.g., the hydroisomerization conditions in reactor 14) include a pressure in the range of about 15 to about 3000 psig (0.10-20.68 MPa), such as about 100 to about 2500 psig (0.69-17.24 MPa).

[00156] In embodiments, the hydroisomerization conditions (e.g., the hydroisomerization conditions in reactor 14) include a feed rate of diesel fuel into the reactor containing the hydroisomerization catalyst in the range of about 0.1 to about 20 h. -1 LHSV, for example, from about 0.1 to about 5 hours -1 LHSV.

[00157] In embodiments, the hydroisomerization conditions (e.g., the hydroisomerization conditions in reactor 14) include feeding hydrogen and diesel feedstock to the reactor in a ratio of from about 2,000 to about 10,000 standard cubic feet of H2 per barrel of diesel feedstock (from about 360 to about 1,800 m 3 H2 / m 3feedstock, for example, from about 2,500 to about 5,000 scf H2 per barrel of diesel fuel feedstock (from about 440 to about 890 m 3 H2 / m 3 feedstock).

[00158] In embodiments, the hydroisomerization conditions (e.g., the hydroisomerization conditions in reactor 14) are as follows: a temperature in the range of about 390 °F to about 800 °F (199 °C to 427 °C), such as about 550 °F to about 750 °F (288 °C to 399 °C), or 570 °F to about 675 °F (299 °C to 357 °C); a pressure in the range of about 15 to about 3000 psig (0.10 to 20.68 MPa), such as about 100 to about 2500 psig. (0.69 to 17.24 MPa); the feed rate of diesel fuel feedstock to the reactor containing the hydroisomerization catalyst is in the range of about 0.1 to about 20 h-1 LHSV, such as about 0.1 to about 5 h -1LHSV; and feeding hydrogen and diesel feedstock to the reactor in a ratio of about 2,000 to about 10,000 standard cubic feet of H2 per barrel of diesel feedstock (about 360 to about 1,800 m 3 H2 / m 3 feedstock, for example, from about 2,500 to about 5,000 scf H2 per barrel of diesel fuel feedstock (from about 440 to about 890 m 3 H2 / m 3feedstock).

[00159] In embodiments, by contacting the diesel fuel feedstock and the hydroisomerization catalyst, the method provides a diesel fuel having an increased ratio of isoparaffins to normal paraffins compared to the diesel fuel feedstock.

[00160] In embodiments, contacting the diesel fuel feedstock and the hydroisomerization catalyst provides a diesel fuel having a lower cloud point and a lower pour point compared to the cloud point and pour point of the diesel fuel feedstock.

[00161] In embodiments, contacting the diesel fuel feedstock and the hydroisomerization catalyst provides a diesel fuel having a lower cloud point and a lower pour point compared to the cloud point and pour point of the diesel fuel feedstock,wherein the diesel fuel is characterized by a cloud point of at least 10°C below the cloud point of the diesel fuel feedstock, and a pour point of at least 10°C below the pour point of the diesel fuel feedstock, or a cloud point of at least 20°C below the cloud point of the diesel fuel feedstock, and a pour point of at least 20°C below the pour point of the diesel fuel feedstock, or a cloud point of at least 30°C below the cloud point of the diesel fuel feedstock,and a pour point at least 30°C lower than the pour point of the diesel fuel feedstock. Hydrotreating the diesel fuel feedstock prior to hydroisomerization

[00162] In embodiments, the diesel fuel feedstock is contacted with a hydrotreating catalyst under hydrotreating conditions prior to contacting the diesel fuel feedstock with the hydroisomerization catalyst. In embodiments, the hydrotreating conditions are as follows: a temperature in the range of about 390 °F to about 800 °F (199 °C to 427 °C), such as about 550 °F to about 750 °F (288 °C to 399 °C), 590 °F to about 675 °F (310 °C to 357 °C); a pressure in the range of about 15 to about 3000 psig. (0.10 to 20.68 MPa), such as from about 100 to about 2500 psig (0.69 to 17.24 MPa); the feed rate of diesel fuel feedstock to the reactor containing the hydroisomerization catalyst is in the range of from about 0.1 to about 20 psig, -1LHSV, for example, from about 0.1 to about 5 hours -1 LHSV; and feeding hydrogen and diesel feedstock to the reactor in a ratio of about 2,000 to about 10,000 standard cubic feet of H2 per barrel of diesel feedstock (about 360 to about 1,800 m 3 H2 / m 3 feedstock), for example, from about 2,500 to about 5,000 scf H2 per barrel of diesel fuel feedstock (from about 440 to about 890 m 3 H2 / m 3

[00163] Hydrotreating catalysts may comprise a refractory inorganic oxide support and a Column 6 metal modifier and / or a Column 8-10 metal modifier. In embodiments, the hydrotreating catalyst comprises a refractory inorganic oxide support, a Column 6 metal modifier, and a Column 8-10 metal modifier. The oxide support may also be referred to herein as a binder. The hydrotreating catalyst support may be made from or contain alumina, silica, aluminosilicate, titanium dioxide, magnesium oxide, zirconia, and the like, or combinations thereof. The hydrotreating catalyst support may comprise amorphous materials, crystalline materials, or combinations thereof. Examples of amorphous materials include, but are not limited to, amorphous alumina, amorphous silica, amorphous aluminosilicate, and the like.

[00164] In embodiments, the hydrotreating substrate may comprise amorphous alumina.When a combination of silica and alumina is used, the distribution of silica and alumina in the support may be either homogeneous or heterogeneous. In some embodiments, the support may be an alumina gel in which silica, aluminosilicate, or alumina-based material is dispersed. The support may also contain refractory materials other than alumina or silica, such as, for example, other inorganic oxides or clay particles, provided that such materials do not adversely affect the hydrogenation activity of the final catalyst and do not result in harmful cracking of the feedstock.

[00165] In embodiments, silica and / or alumina comprise at least about 90 wt.% of the hydrotreating catalyst support, and in some embodiments, the support may consist of at least substantially all of silica or all of alumina.

[00166] In some embodiments, the Columns 8-10 metal modifier(s) of the hydrotreating catalyst comprises Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, or combinations thereof. In embodiments, the Columns 8-10 metal modifier of the hydrotreating catalyst comprises a Column 9 metal, a Column 10 metal, or combinations thereof. In embodiments, the Columns 8-10 metal modifier of the hydrotreating catalyst comprises or is Co and / or Ni. In embodiments, the Columns 8-10 metal modifier of the hydrotreating catalyst comprises or is Ni. In embodiments, the Columns 8-10 metal modifier of the hydrotreating catalyst comprises Co and Ni. In embodiments, the Columns 8-10 metal modifier is an oxide, a hydroxide, or a salt. In embodiments, the Columns 8-10 metal modifier is a salt. The amount of the Columns 8-10 metal modifier in the hydrotreating catalyst is typically from 1 to 20 wt.% (e.g., 2 to 10 wt.%) based on the dry volume weight of the catalyst, calculated as the metal oxide. In embodiments, the Column 6 metal modifier of the hydrotreating catalyst is selected from Cr, Mo, W, and combinations thereof. In embodiments, the Column 6 metal modifier of the hydrotreating catalyst comprises or is Mo. In embodiments, the Column 6 metal modifier is an oxide, an oxoacid, or an ammonium salt of an oxo or polyoxo anion. The amount of Column 6 metal modifier used in the hydrotreating catalyst is typically 5 to 50 wt.% (e.g., 10 to 40 wt.% or 15 to 30 wt.%) based on the dry volume weight of the catalyst, calculated as the metal oxide. In embodiments, the hydrotreating catalyst comprises Ni and Mo.

[00167] In embodiments, a Column 8-10 metal modifier and / or a Column 6 metal modifier of a hydrotreating catalyst may be dispersed on an inorganic oxide support. A number of methods for depositing Column 8-10 and / or Column 6 metals or compounds containing such metals onto a support are known in the art, including ion exchange, impregnation, and co-precipitation. In embodiments, impregnation of the support with Column 8-10 and Column 6 metal modifiers may be carried out at a controlled pH. The Column 8-10 and Column 6 metal modifiers may be added to the impregnation solution in the form of a metal salt, such as a halide salt, and / or an amine complex, and / or a mineral acid salt. Other examples of metal salts that may be used include nitrates, carbonates, and bicarbonates, as well as carboxylic acid salts such as acetates, citrates, and formates.

[00168] Optionally, the impregnated support can be maintained in the impregnation solution, for example, for a period of time in the range of from about 2 to about 24 hours. After impregnation of the oxide support with the Group 8-10 metal modifier and / or the Group 6 metal modifier, the impregnated support can be dried and / or calcined. After drying and calcining the hydrotreating catalyst, the resulting catalyst can be reduced with hydrogen or sulfonated with a sulfur-containing compound, as is common in the art, and placed into service, for example, in a hydrotreating reactor located upstream of a hydroisomerization reactor. EXAMPLES

[00169] The following illustrative examples are not limiting. SUMMARY OF EXAMPLES

[00170] The examples below demonstrate that the processes and methods described herein can efficiently produce high-yield diesel fuels with excellent low-temperature properties. EXAMPLE 1. Production of a catalyst containing zeolite SSZ-91 - catalyst E

[0074] and subsequent

[00172] The SSZ-91 zeolite was then mixed with alumina to obtain a mixture containing 65% by weight of SSZ-91 zeolite. The mixture was extruded, dried, and calcined to form an extrudate base. The extrudate base was impregnated with a solution containing platinum. The impregnated catalyst was then air-dried before calcination to obtain a catalyst (Catalyst E). The total platinum loading of the catalyst product (hereinafter referred to as catalyst E) was 0.6 wt.% (based on the total weight of the catalyst). EXAMPLE 2. Preparation of a catalyst containing zeolite SSZ-32x - catalyst A

[00173] Zeolite SSZ-32x was prepared according to US-A-7468126 (which is incorporated herein by reference) and as described above herein, for example, in paragraph

[00124] et seq.

[00174] Zeolite SSZ-32x was then mixed with alumina to form a mixture containing 45 wt.% zeolite SSZ-32x. The mixture was extruded, dried and calcined to form an extrudate matrix.The extrudate base was impregnated with a platinum-containing solution. The impregnated catalyst was then air-dried before calcination, yielding the catalyst (Catalyst A). The total platinum loading of the catalyst product (hereinafter referred to as Catalyst A) was 1 wt%. EXAMPLE 3. Preparation of a Catalyst Containing Zeolite SSZ-32x - Catalyst B

[00175] A catalyst containing zeolite SSZ-32x was prepared according to Example 2, except that the dried and calcined extrudate was impregnated with a solution containing platinum to obtain a catalyst (hereinafter referred to as Catalyst B) with a total platinum loading of 0.325 wt%. EXAMPLE 4. Preparation of a Catalyst Containing Zeolite SSZ-32 - Catalyst C

[00176] Zeolite SSZ-32 was prepared according to US-A-5,397,454 (which is incorporated herein by reference) and as described above herein, for example, in paragraph

[00108] et seq.

[00177] The SSZ-32 zeolite was then mixed with alumina to produce a mixture containing 65 wt% SSZ-32 zeolite.The mixture was extruded, dried, and calcined to form an extrudate base. The extrudate base was impregnated with a solution containing platinum. The impregnated catalyst was then air-dried before calcination to obtain a catalyst (catalyst C). The total platinum loading of the catalyst product (hereinafter, catalyst C) was 0.325 wt%. EXAMPLE 5. Preparation of a catalyst containing zeolite SSZ-32 - catalyst D

[00178] A catalyst containing zeolite SSZ-32 was prepared according to Example 4, except that the mixture contained 45 wt.% zeolite SSZ-32. The dried and calcined extrudate was impregnated with a platinum-containing solution to produce a catalyst (hereinafter referred to as Catalyst D) with a total platinum loading of 0.325 wt%. EXAMPLE 6

[00179] The hydroisomerization was carried out in a microplant equipped with a fixed-bed, downdraft reactor. Each run was carried out at a total pressure of 600 psig.Before introducing the feedstock, the catalyst was activated using a standard reduction procedure. Feedstock A was passed through a hydroisomerization reactor at an LHSV of 2.6 h. -1 (catalyst E) or 2.71 h -1 (Catalyst A).

[00180] Feedstock A was a feedstock obtained by Fischer-Tropsch synthesis. Its properties are listed in Table 3.Table 3. Properties of Feedstock A Raw materials FT Diesel Fuel API gravity 50,9 Pour point, °C -12 Cloud point, °C -4 SIMDIST TBP (wt%), °F 0,5 261 5 347 30 457 50 525 70 601 90 687 99,5 786

[00181] In Example 6, catalysts A and E were tested separately for processing feedstock A in accordance with the process shown in Fig. 1. Table 4 provides data on the diesel fuel yield and product properties. Both catalysts A and E successfully hydroisomerized the feedstock and reduced the cloud point to about -38 °C. The diesel fuel yield was 95.9 and 99.6 wt.% for catalysts A and E, respectively. Catalyst E, containing zeolite SSZ-91, allowed to obtain 3.7 wt.% more diesel fuel compared to catalyst A. The products of both systems have excellent low-temperature properties. Table 4. Diesel Fuel Yield and Properties Catalysts Catalyst A Catalyst E Total pressure, psig 600 600 H2 Speed, Std. cu. ft. / bbl. 3000 3000 Catalyst temperature, °F 610 605 LHSV, h-1 2,71 2,6 Diesel Fuel Yield in %, 395°F+ 95,9 99,6 Pour point of diesel fuel, °C -44 -43 Diesel fuel cloud point, °C -38 -37 Example 7

[00182] Raw material B is obtained from animal fat. The properties of raw material B are listed in Table 5.Table 5. Properties of raw material B Raw materials Biodiesel API 48 S, ppm 1 N, ppm 0 Pour point, °C 20 Cloud point, °C 22 Boiling range, °F 420-890

[00183] In Example 7, catalysts B and E were used separately to process feedstock B according to the process shown in Fig. 1. Table 6 lists the process conditions, diesel yield, and product properties. Both catalysts B and E successfully hydroisomerized the feedstock and reduced the cloud point to <-9 °C. The diesel yield was 93.3 and 96.1 wt% for catalysts B and E, respectively. This confirms that catalyst E, consisting of zeolite SSZ-91, has excellent performance in the production of biodiesel (diesel fuel) from animal fat. Table 6. Diesel Fuel Yield and Properties Catalysts Catalyst B Catalyst E Total pressure, psig 1000 1000 H2 Speed, Std. cu. ft. / bbl. 5000 5000 Catalyst temperature, °F 613 587 LHSV, h-1 1,3 1,3 Diesel Fuel Yield in %, 380°F+ 93,3 96,1 Diesel fuel cloud point, °C -9 -12 Example 8

[00184] Feedstock C is hydrotreated camelina oil. Its properties are listed in Table 7. This feedstock has high cloud and pour points. Table 7. Properties of Feedstock C Raw materials Hydrotreated camelina oil API gravity 46,8 Cloud point, °C 30 Pour point, °C 26 SIMDIST TBP (wt%), °F 0,5 549 5 575 30 619 50 620 70 621 90 652 99,5 782

[00185] Example 8 utilized catalyst C to process hydrotreated camelina oil according to the process shown in Fig. 1. The test was performed at a total pressure of 1000 psig. The feed was passed through the reactor at an LHSV of 1 hour. -1 The hydrogen to oil ratio was approximately 5000 scf / bbl.

[00186] Table 8 shows the process conditions, diesel fuel yield, and product properties. Diesel fuel yield ranged from 94 to 91 wt%, and cloud point ranged from -11°C to -21°C with varying catalyst temperature.Table 8. Diesel Fuel Yield and Properties Catalysts Catalyst C Total pressure, psig 1000 LHSV, h-1 1 H2 Speed, Std. cu. ft. / bbl. 5000 Catalyst temperature, °F 600 605 610 Gas yield, wt.% 1,72 2,17 2,81 C5-180°F yield, wt% 4,09 5,23 5,78 Yield 180°F-250°F, wt% 0,63 0,71 1,41 Diesel Fuel Yield 250°F+, wt% 93,97 92,34 90,47 Diesel fuel cloud point, °C -11 -16 -21 Pour point of diesel fuel, °C -15 -25 -34 Example 9

[00187] Feedstock D is a hydrotreated canola-based diesel fuel feedstock. Its properties are listed in Table 9.Table 9. Properties of Feedstock D Raw materials Hydrotreated canola-based feedstock API gravity 47,3 Cloud point, °C 26 Pour point, °C 26 SIMDIST TBP (wt%), °F 0,5 519 5 576 30 608 50 611 70 613 90 615 99,5 897

[00188] In Example 9, a layered system (according to the process shown in Fig. 2) with catalyst C in the first hydroisomerization zone and catalyst D in the second hydroisomerization zone was used to process hydrotreated canola oil. The test was performed at a total pressure of 1000 psig. The feed was passed through the reactor at an LHSV of 1 h -1. The hydrogen-to-oil ratio was 4000 scf / bbl.

[00189] Table 10 lists the process conditions (for two separate runs of feedstock D through the layered catalyst system containing catalyst C and catalyst D), diesel yield, and product properties. Diesel yield decreased from 88.7 wt% to 84 wt% as the cloud point decreased from -15°C to -23°C.Table 10. Diesel Yield and Properties Catalysts Catalyst C / Catalyst D Catalyst temperature, °F 600 610 Gas yield, wt.% 2,5 3,6 C5-180°F yield, wt% 3,2 4,3 Yield 180°F-350°F, wt% 6,0 8,7 Diesel Fuel Yield 350°F+, wt% 88,7 84,0 Diesel fuel cloud point, °C -15 -23 Pour point of diesel fuel, °C -31 -45

[00190] It should be understood that the present invention is not limited to the embodiments described above, and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be used alone or in combination with any other feature, and the disclosure extends to all combinations and subcombinations of one or more features described herein.

[00191] For the avoidance of doubt, the present application relates to the subject matter described in the following numbered claims: 1. A method for hydroisomerizing a diesel fuel feedstock, the method comprising contacting the diesel fuel feedstock with a hydroisomerization catalyst, wherein the diesel fuel feedstock comprises or is a biocomponent feedstock or a feedstock obtained by Fischer-Tropsch synthesis, and the hydroisomerization catalyst comprises zeolite SSZ-91, zeolite SSZ-32, or zeolite SSZ-32x.2. A method for improving the quality of a diesel fuel feedstock, wherein the method comprises: contacting the diesel fuel feedstock with a hydroisomerization catalyst under hydroisomerization conditions to produce diesel fuel with a lower cloud point and a lower pour point compared to the cloud point and pour point of the diesel fuel feedstock, wherein the diesel fuel feedstock comprises or is a biocomponent feedstock or a feedstock obtained by Fischer-Tropsch synthesis, and the hydroisomerization catalyst comprises zeolite SSZ-91, zeolite SSZ-32 or zeolite SSZ-32x.3. The method according to paragraph 1 or 2, wherein the hydroisomerization catalyst comprises zeolite SSZ-91 and a metal of groups 8-10.4. The method according to any one of paragraphs 1-3, wherein the hydroisomerization catalyst comprises zeolite SSZ-91, wherein the zeolite SSZ-91 has, in its calcined form, an X-ray diffraction pattern substantially as shown in the following table:. 2-theta(a) Interplanar distance d (nm) Relative intensity(b) 7,67 1,152 M 8,81 1,003 W 12,61 0,701 W 15,30 0,579 W 21,25 0,418 VS 23,02 0,386 VS 24,91 0,357 W 26,63 0,334 W 29,20 0,306 W 31,51 0,284 W (a) ±0,20 (b)wherein the powder diffraction patterns provided are based on a relative intensity scale in which the strongest line in the X-ray diffraction pattern is assigned a value of 100: W=weak (>0 to ≤20); M=medium (>20 to ≤40); S=strong (>40 to ≤60); VS=very strong (>60 to ≤100).5. The method according to any one of paragraphs 1 to 4, wherein the hydroisomerization catalyst comprises SSZ-91 zeolite having a silica to alumina ratio of 70-160, or 80-160, or 80-140, or 100-160.6. The method according to any one of paragraphs 1-5, in which the hydroisomerization catalyst comprises a zeolite SSZ-91 having at least about 80% polytype 6 of the total amount of ZSM-48 type material present in the zeolite SSZ-91, or at least about 90% polytype 6 of the total amount of ZSM-48 type material present in the zeolite SSZ-91.7. The method according to any one of paragraphs 1-6, in which the hydroisomerization catalyst comprises a zeolite SSZ-91, wherein the zeolite SSZ-91 contains from 0.1 to 4.0 wt.% molecular sieve phase of the EUO type.8. The method according to any of paragraphs 1 to 7, wherein the hydroisomerization catalyst comprises zeolite SSZ-91 containing from 0.1 to 4.0 wt.% EU-1.9. The method according to any of paragraphs 1 to 8, wherein the hydroisomerization catalyst comprises zeolite SSZ-91 having a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio of from 1 to 4.10. The method according to any one of paragraphs 1-9, in which the hydroisomerization catalyst comprises a zeolite SSZ-91 having: a silica to alumina ratio from 70 to 160; a morphology characterized as polycrystalline aggregates containing crystallites collectively having an average aspect ratio in the range of from 1 to 4; at least about 80% polytype 6 of the total amount of ZSM-48 type material present in the zeolite SSZ-91; and from 0.1 to 4.0 wt.% of a molecular sieve phase of the EUO type.11.The method according to any one of paragraphs 1-10, wherein the hydroisomerization catalyst comprises from about 5 to about 95 wt.% SSZ-91 zeolite and from about 0.05 to about 2.0 wt.% metal modifier.12. The method according to paragraph 1 or 2, wherein the hydroisomerization catalyst comprises SSZ-32 zeolite and a Group 8-10 metal.13. The method according to any one of paragraphs 1, 2 or 12, wherein the SSZ-32 zeolite has a silica (SiO2) to alumina (Al2O3) molar ratio (SAR) in the range of 25-37.14. The method according to any one of paragraphs 1, 2, 12 or 13, wherein the SSZ-32 zeolite has a crystal size in the range of from about 0.1 μm to about 0.4 μm.15. The method according to any one of paragraphs 1, 2 or 12-14, wherein the SSZ-32 zeolite in the synthesized form has a crystalline structure, the X-ray powder diffraction of which shows the following characteristic lines:. d / n Int.I / Io 11,05 10,05 7,83 4,545 26 10 17 71 4,277 71 3,915 100 3,726 98 16. The method of paragraph 1 or 2, wherein the hydroisomerization catalyst comprises SSZ-32x zeolite and a Group 8-10 metal.17. The method of any of paragraphs 1, 2 or 16, wherein the SSZ-32x zeolite has a silica (SiO2) to alumina (Al2O3) molar ratio (SAR) in the range of 25-37.18. The method of any of paragraphs 1, 2, 16 or 17, wherein the SSZ-32x zeolite has a crystal size in the range of from about 100 to about 400 angstroms.19. The method of any of paragraphs 1, 2 or 16-18, wherein the SSZ-32x zeolite, as synthesized, has a crystalline structure the X-ray powder diffraction of which shows the following characteristic lines: 2Θ Interplanar distance (Å) Intensity Relative intensity (%) (I / Io X 100) 8,00 11,05 15 26 8,80 10,05 6 10 11,30 7,83 10 17 14,50 6,11 1 2 15,75 5,63 3 5 16,50 5,37 3 5 18,10 4,901 7 12 19,53 4,545 41 71 20,05 4,428 6, shoulder 10, shoulder 20,77 4,277 41 71 21,30 4,171 7 12 22,71 3,915 58 100 23,88 3,726 57 98 24,57 3,623 30 52 25,08 3,551 25 43 25,88 3,443 27 47 26,88 3,317 5 9 28,11 3,174 6 10 20. The method according to any of paragraphs 12 to 19, wherein the hydroisomerization catalyst comprises zeolite SSZ-32 or zeolite SSZ-32x and from about 0.05 to about 2.0 weight percent of a metal modifier. 21. The method according to any of paragraphs 1 to 20, wherein the hydroisomerization catalyst is a layered catalyst. 22. The method according to paragraph 21, wherein the hydroisomerization catalyst comprises a first layer comprising a first hydroisomerization catalyst and a second layer comprising a second hydroisomerization catalyst, wherein the first hydroisomerization catalyst is located in the first hydroisomerization zone and the second hydroisomerization catalyst is located in the second hydroisomerization zone. 23. The method according to paragraph 21 or 22 depending on any of paragraphs 1 to 12, wherein the hydroisomerization catalyst comprises at least one layer comprising zeolite SSZ-91. 24.The method according to any of paragraphs 21 to 23, depending on any of paragraphs 1 to 11, wherein the layered catalyst comprises a first layer comprising a first hydroisomerization catalyst and a second layer comprising a second hydroisomerization catalyst, wherein the first or second hydroisomerization catalyst comprises zeolite SSZ-91, and wherein the first and second hydroisomerization catalysts are mutually exclusive. 25. The method according to paragraph 24, wherein the first and second hydroisomerization catalysts comprise zeolite SSZ-91 and a metal of Groups 8 to 10. 26. The method according to any of paragraphs 1, 2 or 12 to 22, wherein the hydroisomerization catalyst is a layered catalyst, wherein the hydroisomerization catalyst comprises at least one layer comprising zeolite SSZ-32 or SSZ-32x. 27.The method according to any of paragraphs 1, 2 or 12-22, wherein the hydroisomerization catalyst is a layered catalyst, wherein the layered catalyst comprises a first layer comprising a first hydroisomerization catalyst and a second layer comprising a second hydroisomerization catalyst, wherein the first or second hydroisomerization catalyst comprises zeolite SSZ-32 or SSZ-32x, wherein the first and second hydroisomerization catalysts are mutually exclusive.28. The method according to paragraph 27, wherein the first and second hydroisomerization catalysts comprise zeolite SSZ-32 and a metal of Columns 8-10.29. The method according to paragraph 27, wherein the first and second hydroisomerization catalysts comprise zeolite SSZ-32x and a metal of Columns 8-10.30.The method of any one of the preceding paragraphs, wherein the diesel fuel feedstock comprises or is a Fischer-Tropsch synthesis feedstock, and the Fischer-Tropsch synthesis feedstock has a 90% distillation temperature of less than about 750°F (about 399°C), such as less than about 700°F (about 371°C).31. The method of any one of the preceding paragraphs, wherein the diesel fuel feedstock comprises or is a bio-based feedstock selected from vegetable oils and animal fats containing triglycerides and free fatty acids, such as wherein the bio-based feedstock is selected from canola oil, corn oil, soybean oil, castor oil, camelina oil, palm oil, and combinations thereof.32.The method according to any one of the preceding paragraphs, wherein the diesel fuel feedstock is contacted with the hydroisomerization catalyst and hydrogen under hydroisomerization conditions in an isomerization reactor, wherein the hydroisomerization conditions are as follows: a temperature in the range of from about 390 °F to about 800 °F (from 199 °C to 427 °C); a pressure in the range of from about 15 to about 3000 psi (from 0.10 to 20.68 MPa); a feed rate of the diesel fuel feedstock into the reactor containing the hydroisomerization catalyst at a rate in the range of from about 0.1 to about 20 h. -1 LHSV; and feeding hydrogen and diesel feedstock to the reactor in a ratio of about 2,000 to about 10,000 standard cubic feet of H2 per barrel of diesel feedstock (about 360 to about 1,800 m 3 H2 / m 333. The method of any one of the preceding paragraphs, further comprising contacting the diesel fuel feedstock with a hydrotreating catalyst under hydrotreating conditions prior to contacting the diesel fuel feedstock with the hydroisomerization catalyst. 34. The method of paragraph 33, wherein the hydrotreating conditions are as follows: a temperature in the range of from about 390 °F to about 800 °F (199 °C to 427 °C); a pressure in the range of from about 15 to about 3,000 psig (0.10 to 20.68 MPa); a feed rate of the diesel fuel feedstock into the reactor containing the hydrotreating catalyst in the range of from about 0.1 to about 20 h -1 LHSV; and feeding hydrogen and diesel feedstock to the reactor in a ratio of about 2,000 to about 10,000 standard cubic feet of H2 per barrel of diesel feedstock (about 360 to about 1,800 m 3 H2 / m 3(feedstock).35. The method of paragraph 1 or paragraphs 3-34, wherein contacting the diesel fuel feedstock and the hydroisomerization catalyst provides a diesel fuel having a lower cloud point and a lower pour point compared to the cloud point and pour point of the diesel fuel feedstock.36.The method according to paragraph 2 or paragraph 35, in which the diesel fuel is characterized by a cloud point of at least 10°C below the cloud point of the diesel fuel feedstock and a pour point of at least 10°C below the pour point of the diesel fuel feedstock, or a cloud point of at least 20°C below the cloud point of the diesel fuel feedstock and a pour point of at least 20°C below the pour point of the diesel fuel feedstock, or a cloud point of at least 30°C below the cloud point of the diesel fuel feedstock and a pour point of at least 30°C below the pour point of the diesel fuel feedstock.37.The use of a hydroisomerization catalyst containing zeolite SSZ-91, zeolite SSZ-32 or zeolite SSZ-32x for producing diesel fuel characterized by a lower cloud point and a lower pour point compared to the cloud point and pour point of the diesel fuel feedstock from which the diesel fuel is obtained, wherein the diesel fuel is obtained by contacting the diesel fuel feedstock and the hydroisomerization catalyst, and the diesel fuel feedstock contains or is a biocomponent feedstock or a feedstock obtained by Fischer-Tropsch synthesis.38.A method for producing diesel fuel characterized by a lower cloud point and a lower pour point compared to the cloud point and pour point of the diesel fuel feedstock from which the diesel fuel is obtained, wherein the method includes bringing the diesel fuel feedstock into contact with a hydroisomerization catalyst containing zeolite SSZ-91, zeolite SSZ-32 or zeolite SSZ-32x, under hydroisomerization conditions to produce diesel fuel characterized by a lower cloud point and a lower pour point compared to the cloud point and pour point of the diesel fuel feedstock from which the diesel fuel is obtained, wherein the diesel fuel feedstock contains or is a biocomponent feedstock or a feedstock obtained by Fischer-Tropsch synthesis.

Claims

1. A method for hydroisomerizing a diesel fuel feedstock, the method comprising contacting the diesel fuel feedstock with a hydroisomerization catalyst, wherein the diesel fuel feedstock comprises or is a biocomponent feedstock or a feedstock obtained by Fischer-Tropsch synthesis, and the hydroisomerization catalyst comprises zeolite SSZ-91.

2. A method for improving the quality of raw materials for diesel fuel, the method comprising: contacting the diesel fuel feedstock with a hydroisomerization catalyst under hydroisomerization conditions to produce diesel fuel with a lower cloud point and a lower pour point compared to the cloud point and pour point of the diesel fuel feedstock, wherein the diesel fuel feedstock comprises or is a biocomponent feedstock or a feedstock obtained by Fischer-Tropsch synthesis, and the hydroisomerization catalyst comprises zeolite SSZ-91.

3. The method according to claim 1, wherein the hydroisomerization catalyst comprises zeolite SSZ-91 and a metal of groups 8-10.

4. The method of claim 1, wherein the SSZ-91 zeolite has, in its calcined form, an X-ray diffraction pattern substantially as shown in the following table: (а) ±0.20 (b) The powder diffraction patterns presented are based on a relative intensity scale in which the strongest line in the X-ray diffraction pattern is assigned a value of 100: W=weak (>0 to ≤20); M=medium (>20 to ≤40); S=strong (>40 to ≤60); VS=very strong (>60 to ≤100).

5. The method according to claim 1, wherein the hydroisomerization catalyst comprises zeolite SSZ-91 having a silicon oxide to aluminum oxide ratio of 70-160, or 80-160, or 80-140, or 100-160.

6. The method of claim 1, wherein the hydroisomerization catalyst comprises a zeolite SSZ-91 having at least about 80% polytype 6 of the total amount of ZSM-48 type material present in the zeolite SSZ-91, or at least about 90% polytype 6 of the total amount of ZSM-48 type material present in the zeolite SSZ-91.

7. The method of claim 1, wherein the SSZ-91 zeolite contains from 0.1 to 4.0 wt.% of a molecular sieve phase of the EUO type.

8. The method of claim 1, wherein the zeolite SSZ-91 contains from 0.1 to 4.0 wt.% EU-1.

9. The method of claim 1, wherein the SSZ-91 zeolite has a morphology characterized as polycrystalline aggregates containing crystallites that collectively have an average aspect ratio of 1 to 4.

10. The method according to claim 1, wherein the zeolite SSZ-91 has: a silicon oxide to aluminum oxide ratio of 70 to 160; morphology characterized as polycrystalline aggregates containing crystallites that collectively have an average aspect ratio in the range of 1 to 4; at least about 80% of the polytype 6 of the total amount of ZSM-48 type material present in the SSZ-91 zeolite; and from 0.1 to 4.0 wt.% of the EUO type molecular sieve phase.

11. The method of claim 1, wherein the hydroisomerization catalyst comprises from about 5 to about 95 wt. % SSZ-91 zeolite and from about 0.05 to about 2.0 wt. % metal modifier.

12. The method according to claim 1, wherein the hydroisomerization catalyst further comprises zeolite SSZ-32 and a metal of groups 8-10.

13. The method of claim 12, wherein the SSZ-32 zeolite has a silicon oxide (SiO2) to aluminum oxide (Al2O3) molar ratio (SAR) in the range of 25-37.

14. The method of claim 12, wherein the SSZ-32 zeolite has a crystal size in the range of about 0.1 μm to about 0.4 μm.

15. The method according to claim 12, wherein the SSZ-32 zeolite in synthesized form has a crystalline structure, the X-ray powder diffraction of which shows the following characteristic lines:

16. The method according to claim 1, wherein the hydroisomerization catalyst further comprises zeolite SSZ-32x and a metal of groups 8-10.

17. The method of claim 16, wherein the SSZ-32x zeolite has a silicon oxide (SiO2) to aluminum oxide (Al2O3) molar ratio (SAR) in the range of 25-37.

18. The method of claim 16, wherein the SSZ-32x zeolite has a crystal size in the range of about 100 to about 400 angstroms.

19. The method according to claim 16, wherein the SSZ-32x zeolite in synthesized form has a crystalline structure, the X-ray powder diffraction of which shows the following characteristic lines:

20. The method of claim 1, wherein the hydroisomerization catalyst further comprises zeolite SSZ-32 or zeolite SSZ-32x and from about 0.05 to about 2.0 wt. % of a metal modifier.

21. The method of claim 1, wherein the hydroisomerization catalyst is a layered catalyst.

22. The method according to claim 21, wherein the hydroisomerization catalyst comprises a first layer containing a first hydroisomerization catalyst and a second layer containing a second hydroisomerization catalyst, wherein the first hydroisomerization catalyst is located in the first hydroisomerization zone and the second hydroisomerization catalyst is located in the second hydroisomerization zone.

23. The method of claim 21, wherein the hydroisomerization catalyst comprises at least one layer containing zeolite SSZ-91.

24. The method of claim 21, wherein the layered catalyst comprises a first layer comprising a first hydroisomerization catalyst and a second layer comprising a second hydroisomerization catalyst, wherein the first or second hydroisomerization catalyst comprises SSZ-91 zeolite, and wherein the first and second hydroisomerization catalysts are mutually exclusive.

25. The method of claim 21, wherein the layered catalyst comprises a first layer containing a first hydroisomerization catalyst and a second layer containing a second hydroisomerization catalyst, wherein the first and second hydroisomerization catalysts comprise SSZ-91 zeolite and a Group 8-10 metal.

26. The method of claim 1, wherein the hydroisomerization catalyst is a layered catalyst, and the hydroisomerization catalyst further comprises at least one layer comprising zeolite SSZ-32 or SSZ-32x.

27. The method of claim 1, wherein the hydroisomerization catalyst is a layered catalyst, wherein the layered catalyst comprises a first layer containing a first hydroisomerization catalyst and a second layer containing a second hydroisomerization catalyst, wherein the first or second hydroisomerization catalyst further comprises an SSZ-32 or SSZ-32x zeolite, and wherein the first and second hydroisomerization catalysts are mutually exclusive.

28. The method of claim 27, wherein the first and second hydroisomerization catalysts comprise SSZ-32 zeolite and a metal of groups 8-10.

29. The method of claim 27, wherein the first and second hydroisomerization catalysts comprise SSZ-32x zeolite and a metal of groups 8-10.

30. The method of claim 1, wherein the diesel fuel feedstock comprises or is a Fischer-Tropsch synthesis feedstock, and the Fischer-Tropsch synthesis feedstock has a 90% distillation temperature of less than about 750°F (about 399°C), such as less than about 700°F (about 371°C).

31. The method of claim 1, wherein the diesel fuel feedstock comprises or is a biocomponent feedstock selected from vegetable oils and animal fats containing triglycerides and free fatty acids, in particular where the biocomponent feedstock is selected from canola oil, corn oil, soybean oil, castor oil, camelina oil, palm oil and combinations thereof.

32. The method of claim 1, wherein the diesel fuel feedstock is contacted with a hydroisomerization catalyst and hydrogen under hydroisomerization conditions in an isomerization reactor, wherein the hydroisomerization conditions are as follows: temperatures ranging from about 390°F to about 800°F (199°C to 427°C); pressure in the range from about 15 to about 3000 psi (0.10 to 20.68 MPa); the feed rate of diesel fuel feedstock into the reactor containing the hydroisomerization catalyst at a rate in the range of about 0.1 to about 20 h -1 LHSV; and feeding hydrogen and diesel fuel feedstock to the reactor in a ratio of from about 2,000 to about 10,000 standard cubic feet of H2 per barrel of diesel fuel feedstock (from about 360 to about 1,800 m 3 H2 / m 3 raw materials).

33. The method of claim 1, further comprising contacting the diesel fuel feedstock with a hydrotreating catalyst under hydrotreating conditions prior to contacting the diesel fuel feedstock with a hydroisomerization catalyst.

34. The method according to claim 33, wherein the hydrotreating conditions are as follows: temperatures ranging from about 390°F to about 800°F (199°C to 427°C); pressure in the range from about 15 to about 3000 psi (0.10 to 20.68 MPa); the feed rate of diesel fuel feedstock into the reactor containing the hydrotreating catalyst at a rate in the range of about 0.1 to about 20 h -1 LHSV; and feeding hydrogen and diesel fuel feedstock to the reactor in a ratio of from about 2,000 to about 10,000 standard cubic feet of H2 per barrel of diesel fuel feedstock (from about 360 to about 1,800 m 3 H2 / m 3 raw materials).

35. The method of claim 1, wherein contacting the diesel fuel feedstock and the hydroisomerization catalyst provides a diesel fuel having a lower cloud point and a lower pour point compared to the cloud point and pour point of the diesel fuel feedstock.

36. The method of claim 2, wherein the diesel fuel is characterized by a cloud point at least 10°C below the cloud point of the diesel fuel feedstock and a pour point at least 10°C below the pour point of the diesel fuel feedstock, or a cloud point at least 20°C below the cloud point of the diesel fuel feedstock and a pour point at least 20°C below the pour point of the diesel fuel feedstock, or a cloud point at least 30°C below the cloud point of the diesel fuel feedstock and a pour point at least 30°C below the pour point of the diesel fuel feedstock.

37. A method for producing diesel fuel having a lower cloud point and a lower pour point compared to the cloud point and pour point of the diesel fuel feedstock from which the diesel fuel is obtained, wherein the method comprises contacting the diesel fuel feedstock and a hydroisomerization catalyst containing SSZ-91 zeolite under hydroisomerization conditions to produce diesel fuel having a lower cloud point and a lower pour point compared to the cloud point and pour point of the diesel fuel feedstock from which the diesel fuel is obtained, wherein the diesel fuel feedstock contains or is a biocomponent feedstock or a feedstock obtained by Fischer-Tropsch synthesis.

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