Selective hydroisomerization catalyst

Abstract

This invention provides a catalyst with high activity for the hydrodeoxygenation and hydroisomerization of alkanes. The catalyst contains a molecular sieve such as SAPO-11, a metal component such as platinum and / or palladium or nickel-tungsten sulfide or nickel-molybdenum sulfide, and a binder such as γ-alumina. The catalyst exhibits a high proportion of weak acid sites and a relatively uniform distribution of the metal component across the molecular sieve and binder.

Description

[0001] Priority Statement

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 145,474, filed February 3, 2021, the entire contents of which are incorporated herein by reference.

[0003] This application claims priority to provisional application 63 / 145,474, filed on February 3, 2020, the entire contents of which are incorporated herein by reference.

[0004] This invention relates to a method for preparing catalytically active materials, and particularly to a catalyst for the hydroisomerization of hydrocarbon mixtures suitable for use as diesel fuel, jet fuel, lubricant or household fuel oil, and to a hydroisomerization method employing such a catalyst.

[0005] The feed hydrocarbon mixtures associated with this disclosure may be derived from atmospheric or vacuum fractionation of hydrocarbon mixtures having a wide boiling range. The hydrocarbon mixtures may be derived from a variety of sources, including mineral oils, renewable oils (including oils of vegetable and / or animal origin), and synthetically produced hydrocarbons (e.g., hydrocarbons synthesized from syngas via the well-known Fischer-Tropsch reaction, which is generated from biomass and coal gasification, natural gas reforming, coke oven gas, etc.), and mixtures of hydrocarbons from these sources.

[0006] As is well known to those skilled in the art, for example according to the European standard EN 590 for diesel fuel, depending on the source of the hydrocarbon mixture, the hydrocarbon mixture may have satisfactory cold flow characteristics for a particular application at any temperature, but for some other applications that are typically associated with seasonal temperature variations (typically in winter), the cold flow characteristics may need to be improved, or the cold flow characteristics may need to be improved throughout the year.

[0007] Problematic cold flow properties, namely crystallization or partial solidification at low temperatures, are most commonly associated with long (C7+) straight-chain positive-chain alkanes, which can be isomerized to form branched isomerized alkanes (isoalkanes) with improved cold flow properties.

[0008] Several methods for optimizing cold flow characteristics are available, and because they all aim to reduce the presence of waxes such as n-chain alkanes or at least their effect, these methods are often referred to as dewaxing.

[0009] Product blending can improve cold flow characteristics by diluting the feedstock with a low-boiling-point stream (e.g., kerosene) or a suitable additive (an inhibitor of crystal formation) to the feedstock oil. Although technically simple, these methods have traditionally been expensive.

[0010] Products with acceptable cold-flow characteristics can also be obtained through catalytic hydrocracking of the feedstock. This reaction breaks down long-chain alkanes, producing shorter molecules with satisfactory cold-flow characteristics. Hydrocracking results in product loss due to the formation of hydrocarbons with boiling points outside the desired boiling range and the significant consumption of hydrogen.

[0011] Another approach to improving the cold flow characteristics of the product is catalytic hydroisomerization. Suitable catalysts are active in promoting hydroisomerization reactions, thereby providing isomers with various degrees of branching from the original straight-chain alkanes.

[0012] Compared to hydrocracking, hydroisomerization allows for higher yields of the product fraction of interest and lower hydrogen consumption. This method requires the presence of hydrogen.

[0013] The dewaxing or hydroisomerization process is carried out in the presence of a catalyst, according to this disclosure, comprising a noble metal component selected from Group VIII of the periodic table and supported on a support comprising a metal oxide (such as alumina, silica, titanium dioxide, or silica-alumina or a combination thereof) and a molecular sieve having a topological structure (such as AEI, AEL, AFO, AFX, ATO, BEA, CHA, FAU, FER, MEL, MFI, MOR, MRE, MTT, MWW, or TON).

[0014] As in most chemical reactions, especially those involving complex mixtures such as diesel fuel mixtures, multiple parallel reactions can occur. In the case of dewaxing via hydroisomerization, these parallel reactions can typically be hydrocracking reactions with small hydrocarbons as products that are unsuitable as part of the diesel fuel mixture, thus representing yield losses and therefore economic losses as well as costs due to hydrogen consumption. Throughout the process, the yield is optimized, particularly by optimizing process conditions and the catalyst used.

[0015] As used herein, cold flow parameter values ​​are expressed by temperature, reflecting the viscosity of a hydrocarbon mixture at low temperatures, and include parameters such as cloud point, pour point, freezing point, and cold filter plugging point (CFPP). These parameters share the common characteristic of defining the required low viscosity of diesel fuel under cold conditions, as specified in the standard EN 590, which specifies the requirements for diesel fuel. For most practical purposes, the parameters are affected by the same chemical mechanisms, and unless otherwise stated, the terms "improvement of cold flow characteristics" or "improvement of any of these parameters" should be understood as equivalent.

[0016] As used herein and as understood by those skilled in the art of refining, isoparaffins should be considered as any branched alkanes, which differs from the strict definition of isoparaffins (alkanes having a single methyl group near the end of the carbon chain).

[0017] As used herein, “feedback” or “feedback oil” shall include any stream derived from one or more of mineral oils, renewable oils, or products derived from Fischer-Tropsch synthesis of synthetic gas, whose cold flow characteristics require improvement.

[0018] Materials that are catalytically active in hydroisomerization should be understood as materials that have significant catalytic activity for hydroisomerization under the conditions used, but as those skilled in the art will recognize, most reactions will exhibit a certain amount of side reactions, and even when the side reactions are comparable to or exceed the extent of the desired hydroisomerization reaction, the material should be considered catalytically active in hydroisomerization in which a certain amount of hydroisomerization occurs.

[0019] As used herein, the unit NL / L should indicate the volume of gas per volume of liquid (in liters at 15°C and 1 bar) (in nominal liters, i.e., in liters at 0°C and 1 bar).

[0020] As used herein, the term precursor of a catalytically active material should be understood as a material that can be converted into a catalytically active material through activation methods such as reduction.

[0021] As used in this paper, the term molecular sieve topology is used in the sense described in "Atlas of Zeolite Framework Types," Sixth Revised Edition, Elsevier, 2007, and according to which it uses a three-letter framework type code.

[0022] In a broad form, this disclosure relates to precursors or catalytically active materials comprising dehydrogenated metal functional groups (such as those provided by platinum, palladium, nickel, nickel-molybdenum sulfides, or nickel-tungsten sulfides), molecular sieves, and metal oxide supports, characterized in that the metal functional groups are distributed between the molecular sieve and the support, wherein 50% or 60% or 65% of the metal functional groups are distributed on the molecular sieve, and the associated beneficial effects of such catalytically active materials are highly active and selective for dewaxing or hydroisomerization.

[0023] In another embodiment, the molecular sieve is selected from one or more materials having an AEI, AEL, AFO, AFX, ATO, BEA, CHA, FAU, FER, MEL, MFI, MOR, MRE, MTT, MWW, or TON topology, such as EU-2, ZSM-11, ZSM-22, ZSM-23, ZSM-48, SAPO-5, SAPO-11, SAPO-31, SAPO-34, SAPO-41, SSZ-13, SSZ-16, SSZ-39, MCM-22, zeolite Y, magnesium alkali zeolite, mordenite, ZSM-5, or zeolite β. The relevant beneficial effect of such materials is their activity in the dewaxing or hydroisomerization of straight-chain hydrocarbons. SAPO-11 has been found to be particularly useful.

[0024] This disclosure relates to a catalytically active material comprising a metal component, a molecular sieve, and a metal oxide support, wherein 40%-60% of the metal component is dispersed on the molecular sieve and 40%-60% of the metal component is dispersed on the metal oxide support. The metal component may be selected from platinum, palladium, nickel, nickel-molybdenum sulfide, or nickel-tungsten sulfide. Preferably, the metal component is selected from platinum or nickel-tungsten sulfide. It has been found that the metal component is distributed fairly uniformly between the molecular sieve and the metal oxide support, and may be equivalent to 50% of the metal component being dispersed on the molecular sieve and 50% of the metal component being dispersed on the metal oxide support. The metal oxide support may be selected from alumina, silica, silica-alumina, and titanium dioxide, or mixtures thereof. Preferably, the metal oxide support is alumina, and more preferably it is γ-alumina. The catalytically active material comprises a molecular sieve having an AEL topology, and more specifically, SAPO-11. Most acidic sites on SAPO-11 are weak to moderately acidic sites. More specifically, at least 50% of the total acidic sites on SAPO-11 are weakly acidic sites, and at least 60%-80% of the external acidic sites on SAPO-11 are weakly acidic sites.

[0025] Materials with catalytic activity in hydroisomerization are typically particles a few millimeters in diameter. The preparation usually involves forming a stable support, followed by impregnation with an active metal. This stable support typically comprises a metal oxide and a molecular sieve, which can be a zeolite. A stable support with high porosity is prepared to ensure maximum surface area, and it is generally desirable to impregnate the active metal across the entire volume of the support.

[0026] Hydrodeoxygenated renewable fuels derived from renewable feedstocks, such as tallow from vegetable oils and animal sources, and their blends, consist of n-alkanes. Based on their cloud point (ASTM D 2500) and pour point (ASTM D1655: Jet A -40°C maximum, Jet A -1 -47°C maximum, D 5972, D 7153, D 7154, or D 2386), they exhibit poor cold-flow characteristics and typically require hydroisomerization to improve these characteristics. Existing catalysts used include bifunctional supported hydroisomerization catalysts with dehydrogenated metal functional groups (such as Pt, Pd, Ni, Pt / Pd, Ni...). x Mo y S z Ni x W y S z The third component of the supported hydroisomerization catalyst is a binder, typically composed primarily of γ-alumina, which provides the dehydrogenated metal functional groups, isomerized acid functional groups, and binder components. An effective dewaxing catalyst will have a preferred combination (type, concentration) of dehydrogenated metal functional groups, isomerized acid functional groups, and binder components, providing excellent selectivity (yields of 250℉–700℉ fractions) with desired levels of cold flow characteristic modulation (e.g., cloud point reduction).

[0027] Alternatives to the above-identified preferred supported hydroisomerization catalysts may be to treat the hydrodeoxygenation effluent with a bifunctional catalyst that does not include the shape-selective molecular sieve component, or to replace the shape-selective molecular sieve with a non-shape-selective molecular sieve (e.g., octahedral zeolite).

[0028] Compared to existing technologies, this invention is unique in its application to molecular sieves for isomerizing acid functional groups. Compared to catalysts having a support entirely composed of a non-shape-selective support (such as amorphous silica alumina) and having the same type and concentration of metal (e.g., Pt) dispersed on the support, this new catalyst retains at least 6% of the 250F-700F distillate at a total liquid product cloud point of -30°C. The temperature required to achieve the same cloud point reduction is, i.e., the activity is in the range of 5℉-10℉.

[0029] Molecular sieve AEL SAPO-11 was extruded together with pseudoboehmite that had been gelled with an aqueous nitric acid solution. The extrudate was dried and then calcined to convert the pseudoboehmite into γ-alumina. Typical calcination conditions were: residence time of 30-90 minutes, 1200-1500°F. The resulting calcined support was impregnated with 0.25 wt% Pt (e.g., TAPC platinum tetraammonium chloride Pt precursor) and then oxidized in a furnace / oxidizer at 700-900°F for 30-90 minutes. The catalyst was then reduced with flowing hydrogen at 650-700°F for 4-6 hours. After the metal in the catalyst has been reduced, the catalyst can be processed with hydrodeoxygenated renewable feedstock (up to 100%) under the following processing conditions to achieve the desired cold flow characteristics: 500 psig-1400 psig, 1500 Scfb-10000 Scfb; hydrogen: feedstock, 550℉-750℉, 0.25 LHSV-2.5 LHSV.

[0030] X-ray chemical mapping of the catalyst samples prepared as described above shows that the platinum content on SAPO-11 and γ-alumina is substantially equal to 0.27 ± 0.07 wt% Pt / SAPO-11 and 0.29 ± 0.09 wt% Pt / alumina. Further analysis of the platinum particle size revealed that 83.6% of all platinum particles were 2 nm or smaller. 50% of the platinum was on the molecular sieve, meaning that 46% of the total platinum was less than 2 nm and located on the molecular sieve. Chemical mapping was performed by scanning transmission electron microscopy. The nanoparticle diameter was determined by averaging each possible diameter passing through the particle center between two tangent points. Atom counting was performed by collecting a series of images at atomic resolution (5.1 Mx magnification) over a sufficiently thin region of the support. For each sample, the atomic count was 265 nm. 2 The scanned area is used to count the intensity contributions from individual atoms. For simplicity, morphology is ignored, so the density of individual atoms per square area represents the number of individual atoms per image area relative to the carrier surface area.

[0031] Additional characterization of the material was performed by measuring the acidity of the molecular sieve. In the tests conducted, the external acidity of SAPO-11 was determined by testing the absorption of chloridine, and the total acidity was determined by testing the absorption of pyridine. Each sample was 10 mg, ground into a fine powder, and pressed into self-supporting granules with a diameter of 13 mm. Individual experiments were conducted on each sample of pyridine and chloridine. The samples were pretreated in helium at 500 °C for 2 hours, then adsorbed with pyridine or chloridine at 150 °C for 1 hour, followed by desorption three times at 150 °C, 300 °C, and 450 °C for 1 hour each. The Brønsted acid strength distribution of the total acidity primarily showed weak and intermediate sites. For external sites, the acid strength distribution for SAPO-11 powder was mainly biased towards weak sites, followed by intermediate sites. Very few strong sites were present. The results using pyridine were weak 0.07, intermediate 0.06, strong 0.0005, and total 0.14; all measurements are area / mg. Similar results were found for the acidity of external sites, with a relative value of 0.11 for weak sites, 0.03 for moderate sites, 0.01 for strong sites, and 0.15 for total sites.

[0032] In another example, the molecular sieve SAPO-11 with the same γ-alumina support was impregnated with nickel-tungsten metal, wherein the Ni loading was 1 wt% to 5 wt% and the W loading was 10 wt% to 30 wt%. Example

[0033] SAPO-11 mother sample

[0034] The SAPO-11 master sample was divided into four portions, each formed into a cylindrical extrusion from alumina (metal oxide portion), and then calcined to prepare four catalyst support extrusions. Each of the four support extrusions was impregnated with the same concentration of a Group VIII metal, followed by oxidation and reduction to activate the catalyst for hydroisomerization. 40%-60% of the metal component was dispersed on the molecular sieve portion and 40%-60% of the metal component was dispersed on the metal oxide portion of the cylindrical extrusion support.

[0035] Example 1

[0036] The first catalyst support was prepared at baseline temperature and steam level. The carbon content was 838 ppm. Following impregnation, oxidation, and reduction, the catalyst performance was evaluated at the standard operating conditions necessary to lower the cloud point of the n-hexadecane feedstock by 48.5℉. The yield of the 250F-700F+ product boiling fraction exceeded 90%, and this yield was used as the baseline for comparison with Examples 2, 3, and 4.

[0037] Example 2

[0038] A second catalyst support was prepared at baseline temperature and 120% of baseline vapor level. The carbon content was 590 ppm. Following impregnation, oxidation, and reduction, the catalyst performance was evaluated under the stringent standard operating conditions necessary to lower the cloud point of the n-hexadecane feedstock by 48.5℉. The yield of the 250F-700F+ product boiling point fraction exceeded that of Example 1 by 0.9%, calculated as a difference.

[0039] Example 3

[0040] A third catalyst support was prepared at the baseline temperature and a baseline vapor level of 140%. The carbon content was 221 ppm. Following impregnation, oxidation, and reduction, the catalyst performance was evaluated under the stringent standard operating conditions necessary to lower the cloud point of the n-hexadecane feedstock by 48.5 °C. The yield of the 250°F-700°F+ product boiling point fraction exceeded that of Example 1 by 1.1%, calculated as a difference.

[0041] Example 4

[0042] A fourth catalyst support was prepared at a baseline temperature of +175℉ and a baseline vapor level of 140%. The carbon content was 110 ppm. The catalyst performance was evaluated under the harshness of standard operating conditions required to lower the cloud point of the n-hexadecane feedstock by 48.5℉ after impregnation, oxidation, and reduction. The yield of the 250F-700F+ product boiling point fraction exceeded that of Example 1 by 1.8%, calculated as a difference.

[0043] Specific implementation plan

[0044] While the following description is presented in conjunction with specific embodiments, it should be understood that the description is intended to illustrate, and not limit, the scope of the foregoing description and the appended claims.

[0045] A first embodiment of the present invention is a catalytically active material comprising a metal component and at least a molecular sieve, a metal oxide, and a carbon material as a support, wherein 40%-60% of the metal component is dispersed on the molecular sieve and 40%-60% of the metal component is dispersed on the metal oxide, and wherein 25 wppm-1000 wppm of carbon material is contained in a support excluding the loaded active metal component. Embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described above, wherein 25 wppm-500 wppm of carbon is contained in a support excluding the loaded active metal component. Embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described above, wherein the metal component is selected from platinum, palladium, nickel, combinations of platinum and / or palladium and / or nickel, nickel-molybdenum sulfide, or nickel-tungsten sulfide. Embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described above, wherein the metal component is selected from platinum or nickel-tungsten sulfide. The embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described above, wherein 50% of the metal component is dispersed on the molecular sieve, and 50% of the metal component is dispersed on the metal oxide. The embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described above, wherein the precursor of the metal oxide support is selected from alumina, silica, silica-alumina, and titanium dioxide. The embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described above, wherein the metal oxide is alumina. The embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described above, wherein the metal oxide is γ-alumina. The embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described above, wherein the molecular sieve has an AEI framework type. The embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described above, wherein the molecular sieve is SAPO-11. The embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described in this paragraph, wherein at least 50% of the acid sites on SAPO-11 are weak acid sites. The embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described in this paragraph, wherein at least 60%-80% of the external acid sites on SAPO-11 are weak acid sites.

[0046] A second embodiment of the present invention is a method for dewaxing a hydrocarbon or hydrocarbon mixture, the method involving contacting the hydrocarbon or hydrocarbon mixture with a catalytically active material in the presence of hydrogen under dewaxing conditions. The catalytically active material comprises a metal component and includes at least a molecular sieve, a metal oxide, and a carbon material as a support, wherein 40%-60% of the metal component is dispersed on the molecular sieve and 40%-60% of the metal component is dispersed on the metal oxide, and wherein 25 wppm-1000 wppm of carbon material is contained in a support excluding the loaded active metal component. Embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described above in this paragraph, wherein 25 wppm-500 wppm of carbon is contained as a carbon material in a support excluding the loaded active metal component. Embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described above in this paragraph, wherein the metal component is selected from platinum, palladium, nickel, combinations of platinum and / or palladium and / or nickel, nickel-molybdenum sulfide, or nickel-tungsten sulfide. The embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described in this paragraph, wherein the metal component is selected from platinum or nickel-tungsten sulfide. The embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described in this paragraph, wherein 50% of the metal component is dispersed on the molecular sieve, and 50% of the metal component is dispersed on a metal oxide support. The embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described in this paragraph, wherein the molecular sieve is SAPO-11. The embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described in this paragraph, wherein the metal oxide support is alumina. The embodiments of the present invention are one, any, or all of the embodiments described above in this paragraph up to the first embodiment described in this paragraph, wherein the metal oxide support is γ-alumina.

[0047] Although no further detailed description has been provided, it is believed that those skilled in the art will be able to make full use of the invention by employing the foregoing description and will be able to readily identify the essential features of the invention without departing from its spirit and scope, and to make various changes and modifications to adapt it to various uses and situations. Therefore, the foregoing preferred embodiments should be understood as illustrative only and not as limiting the remainder of this disclosure in any way, and are intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0048] In the foregoing, all temperatures are expressed in degrees Celsius, and all portions and percentages are by weight unless otherwise specified.

Claims

1. A catalytically active material, comprising a metal component, and comprising as a support at least a molecular sieve, a metal oxide and a carbon material, wherein 40-60% of the metal component is dispersed on the molecular sieve and 40-60% of the metal component is dispersed on the metal oxide, and wherein 25-1000 wppm carbon as carbon material is in the support not including the supported active metal component; wherein the metal component is selected from platinum, palladium, nickel, combinations of platinum and / or palladium and / or nickel, nickel molybdenum sulfides or nickel tungsten sulfides; wherein the metal oxide is selected from alumina, silica, silica-alumina and titania; wherein the molecular sieve is SAPO-11.

2. The catalytically active material according to claim 1, wherein 25-500 wppm carbon as carbon material is in the support not including the supported active metal component.

3. The catalytically active material according to claim 1, wherein the metal component is selected from platinum or nickel tungsten sulfides.

4. The catalytically active material according to claim 1, wherein 50% of the metal component is dispersed on the molecular sieve and 50% of the metal component is dispersed on the metal oxide.

5. A process for dewaxing a hydrocarbon or a mixture of hydrocarbons, which process involves contacting the hydrocarbon or mixture of hydrocarbons with a catalytically active material in the presence of hydrogen under dewaxing conditions, wherein the catalytically active material is a catalytically active material according to any one of claims 1-4.