Middle distillate hydrocracking catalyst highly containing stabilized y zeolite with enhanced acid site distribution

Abstract

To provide an improved hydrocracking catalyst containing a stabilized Y zeolite (SY) having an enhanced acid site distribution as compared to conventional SY zeolites.SOLUTION: A hydrocracking catalyst comprises: a support; an amorphous silica alumina material; an SY zeolite having an acid site distribution index factor between 0.02 and 0.12; and at least one metal selected from the group consisting of elements from Group 6 and Groups 8-10 of the Periodic Table. Preferably, the SY zeolite is a high nanopore volume (HNPV) SY zeolite having a nanopore volume in the 20 nm to 50 nm range of 0.15 to 0.6 cc / g.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] Described herein is an improved hydrocracking catalyst containing stabilized Y zeolite (SY) that has a higher acid site distribution than conventional SY zeolites. Furthermore, the SY zeolite is characterized by a high nanopore volume (HNPV).

[0002] The final hydrocracking catalyst utilizing the HNPV SY zeolite component exhibits lower gas production (e.g., production of less valuable C1-C4 gases), higher hydrogen efficiency, and higher yields (380 to 700°F) and quality of heavy middle distillate products compared to conventional SY-based hydrocracking catalysts. [Background technology]

[0003] Catalytic hydroprocessing refers to a petroleum refining process in which a carbonaceous feedstock is contacted with hydrogen and a catalyst at elevated temperatures and pressures for the purposes of removing undesirable impurities and / or converting the feedstock into improved products.

[0004] Hydrocracking is an important refining process used to produce and process middle distillate products boiling in the range of 250 to 700°F (121 to 371°C), such as kerosene and diesel. Hydrocracking feedstocks contain large amounts of organic sulfur and nitrogen, which must be removed to meet fuel specifications.

[0005] Hydrocrackers have always produced environmentally friendly products, even before the increasing environmental regulations on products. No other process can take low-value, high-aromatic, high-sulfur, and high-nitrogen feedstocks and produce a full slate of desirable and attractive products: LPG, high-quality diesel fuel, hydrogen-rich FCC feed, ethylene cracking feed, and / or high-quality lube unit feedstock. Modern hydrocracking was commercialized in the early 1960s. These early units converted light feedstocks (from atmospheric crude towers) into high-value, high-demand gasoline products. Additionally, the high volumetric gain of hydrocrackers (over 20%) significantly added to the refinery's bottoms line. Due to these strong attributes, hydrocracker capacity has steadily increased over the years.

[0006] Tightening environmental regulations for gasoline and diesel have made hydrocracking the most important process, resulting in ever-increasing global capacity. The most recent basic hydrocrackers were designed to maximize the production of middle distillates from challenging feedstocks such as FCC light cycle oil, heavy vacuum gas oil, and heavy coker gas oil. Like their predecessors, modern hydrocrackers produce high-value, environmentally friendly distillate products, including large quantities of ultra-low sulfur diesel (ULSD), even with rapidly becoming more demanding feedstocks. While early-generation hydrocrackers were capable of 10,000 barrels per day, today many new units exceed 100,000 barrels per day.

[0007] Increasing demand for middle distillates, a declining market for high-sulfur fuel oil, and increasingly stringent environmental regulations have placed enormous margin pressure on refineries, especially those with lower Nelson Complexity Index conversion capacities, and even led to the closure of many. This recent trend has led to grassroots projects for fraction-oriented conversion technologies. Few, if any, refineries have conversion strategies focused on FCC technology, with many FCC units operating in less stringent fraction modes or, in some cases, being converted into propylene units. Hydrocracking offers greater flexibility in crude processing opportunities while producing premium-grade, clean fuels that improve refinery margins. Accordingly, in the past decade alone, more than 90 fixed-bed hydrocracking units have been licensed worldwide. Many of the new refineries and refinery-related projects are targeting operating capacities of 400,000 BPSD or more, thereby increasing average hydrocracker capacity beyond traditional single-train capacities of 65,000 to 70,000 BPSD in many cases.

[0008] Generally, conventional hydrocracking catalyst extrudates are composed of (1) at least one acidic component, which may be a crystallized aluminosilicate and / or amorphous silica-alumina; (2) a binder material, such as alumina, titania, silica, etc.; and (3) one or more metals selected from Groups 6 and 8-10 of the periodic table, particularly nickel, cobalt, molybdenum, and tungsten.

[0009] There are two broad classes of reactions that occur in hydrocracking processes. The first class of reactions involves hydrotreating, where impurities such as nitrogen, sulfur, oxygen, and metals are removed from the feedstock. The second class of reactions involves hydrocracking, where carbon-carbon bonds are cleaved or hydrocracked in the presence of hydrogen to produce lower boiling products.

[0010] The hydrocracking catalyst is bifunctional, with the hydrogenation / dehydrogenation reaction promoted by a metal component and the cracking reaction promoted by a solid acid component, both of which require the presence of high-pressure hydrogen.

[0011] During hydrocracking, contacting the feedstock with a catalyst forms carbocations that either undergo isomerization and dehydrogenation to form olefins or beta-crack to form olefins and new carbocations. These intermediate products undergo hydrogenation to form lower boiling middle distillate products as shown in the table below. [Table 1] Summary of the Invention [Problem to be solved by the invention]

[0012] When conventional SY zeolites are used in hydrocracking processes, low-value naphtha is formed from the undesirable secondary hydrocracking of material in the jet boiling range. Therefore, there is currently a need for hydrocracking catalysts that exhibit a higher degree of selectivity towards the production of heavy middle distillate products (380 to 700°F), particularly diesel products. [Means for solving the problem]

[0013] Described herein are improved final hydrocracking catalysts containing high nanopore volume HNPV SY zeolite components, which are characterized by enhanced acid site distribution compared to conventional SY zeolites.

[0014] The HNPV SY zeolite component utilized in the catalysts described herein is characterized by a higher amount of pores in the 20 to 50 nm range compared to conventional SY zeolites, and the HNPV SY also has an enhanced acid site distribution index factor between 0.02 and 0.12.

[0015] By utilizing SY zeolites with higher nanopore volumes in the 20 to 50 nm range and enhanced acid site distribution as described herein below, the final hydrocracking catalyst has been found to exhibit higher selectivity to the production of heavier middle distillate products in the 380 to 700°F (193 to 371°C) boiling range, particularly middle distillates in the diesel boiling range. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a transmission electron microscope (TEM) image of the conventional USY used in the preparation of the conventional hydrocracking catalyst produced in Example 1.

[0017] [Figure 2] FIG. 2 is a TEM image of the HNPV USY used in the preparation of the specific hydrocracking catalysts produced in the examples.

[0018] [Figure 3] FIG. 3 is the pore size distribution of the conventional USY and HNPV USY used in the preparation of the hydrocracking catalyst produced in Example 1, as determined by N2 adsorption.

[0019] [Detailed Description of the Invention] <Introduction> "Periodic Table" refers to the IUPAC Periodic Table of the Elements, edition dated June 22, 2007, and the numbering system for the Periodic Table Groups as set forth in Chemical and Engineering News, Vol. 63(5), p. 27 (1985).

[0020] "Hydrotreating" or "hydroconversion" refers to a process in which a carbonaceous feedstock is contacted with hydrogen and a catalyst at elevated temperatures and pressures for the purposes of removing undesirable impurities and / or converting the feedstock to desirable products. Such processes include, but are not limited to, methanation, water-gas shift reaction, hydrogenation, hydrotreating, hydrodesulfurization, hydrodenitrogenation, hydrodemetallization, hydrodearomatization, hydroisomerization, hydrodewaxing, and hydrocracking, including selective hydrocracking. Depending on the type of hydrotreating and reaction conditions, the products of hydrotreating can exhibit improved physical properties, such as improved viscosity, viscosity index, saturates content, low temperature properties, volatility, and depolarizability.

[0021] "Hydrocracking" refers to processes in which hydrogenation and dehydrogenation involve the cracking / fragmentation of hydrocarbons, e.g., converting heavier hydrocarbons to lighter hydrocarbons, or converting aromatics and / or cycloparaffins (naphthenes) to acyclic branched paraffins.

[0022] "Column" refers to a distillation column or columns that separate a feedstock into one or more fractions having different cut points.

[0023] "Cut point" refers to the temperature on the true boiling point ("TBP") curve (i.e., the batch process curve of the percentage of feed removed in the heavy reflux column versus the temperature reached to achieve that removal) at which a predetermined degree of separation is reached.

[0024] "True boiling point" (TBP) refers to the boiling point of the feed as measured by ASTM D2887-13.

[0025] "Bottoms fraction" means the heavy fraction separated by fractional distillation from the feedstock as the non-vaporized (i.e., residue) fraction.

[0026] "Hydrocracking heavy fraction" means the heavy fraction after undergoing hydrocracking.

[0027] "Hydrocarbon-based" means a compound or substance that contains atoms of hydrogen and carbon, but may include heteroatoms such as oxygen, sulfur, or nitrogen.

[0028] "Middle distillates" includes the following products: [Table 2]

[0029] "LHSV" means liquid hourly space velocity.

[0030] "SCF / BBL" (or scf / bbl, or scfb or SCFB) refers to the unit of standard cubic feet of gas (N2, H2, etc.) per barrel of hydrocarbon feed.

[0031] "Nanopore" means a pore having a diameter between 2 nm and 50 nm, inclusive.

[0032] "Stabilized Y zeolite" and "SY" are any Y zeolite with a higher framework silicon content than the starting (as-synthesized) Na-Y precursor. Exemplary SY zeolites include ultra-stabilized Y (USY) zeolite, very ultra-stabilized Y (VUSY) zeolite, and the like.

[0033] Where permitted, all publications, patents, and patent applications cited in this application are incorporated herein by reference in their entirety to the extent such disclosure is not inconsistent with the present invention.

[0034] Unless otherwise specified, the recitation of a genus of elements, materials, or other components, from which individual components or mixtures of components may be selected, is intended to encompass all possible subgenus combinations of the listed components and mixtures thereof. Also, the word "include" and variations thereof are intended to be open-ended, such that the recitation of listed items does not exclude other similar items that may also be useful in the materials, compositions, and methods of the invention.

[0035] Unless otherwise specified, all numerical ranges recited herein are inclusive of the lower and upper limits stated in the range.

[0036] The properties of the materials described herein are measured as follows: (a) Bronsted Acidity: Determined by isopropylamine-temperature-programmed desorption (IPam TPD) adapted from published descriptions of TJ Gricus Kofke, RK Gorte, W.E. Farneth, J. Catal. 114, 34-45, 1988; TJ Gricus Kofke, RJ Gorte, G.T. Kokotailo, J. Catal. 115, 265-272, 1989; JG Tittensor, RJ Gorte, and D.M. Chapman, J. Catal. 138, 714-720, 1992. (b) SiO2 / Al2O3 Ratio (SAR): Determined by ICP elemental analysis. An infinite (∞) SAR represents the absence of aluminum in the zeolite, i.e., the silica-to-alumina molar ratio is infinite. In that case, the molecular sieve is composed essentially entirely of silica. (c) Surface Area: Determined by N2 adsorption at boiling temperature. BET surface area is calculated by the 5-point method at P / P0 = 0.050, 0.088, 0.125, 0.163, and 0.200. Samples are first pretreated at 400°C for 6 hours in the presence of a stream of dry N2 to remove adsorbed volatiles such as water or organics. (d) Nanopore and micropore volumes: determined by N2 adsorption at boiling temperature. Micropore volumes are calculated by the t-plot method at P / P0 = 0.050, 0.088, 0.125, 0.163, and 0.200. Samples are first pretreated at 400 °C for 6 h in the presence of a stream of dry N2 to remove adsorbed volatiles such as water or organics. (e) Nanopore size: Determined by N2 adsorption at boiling temperature. Mesopore size is calculated from N2 isotherms by the BJH method described by EP Barrett, LG Joyner, and PP Halenda in "Determination of Pore Volume and Area Distribution in Porous Materials. I. Computer-Aided Calculations from Nitrogen Isotherms," J. Am. Chem. Soc., Vol. 73, pp. 373-380, 1951. Samples are first pretreated at 400°C for 6 hours in the presence of dry N2 flow to remove adsorbed volatiles such as water or organic matter. (f) Total nanopore volume: Determined by N adsorption at boiling temperature with P / P = 0.990. The sample is first pretreated at 400 °C for 6 h in the presence of dry N flow to remove adsorbed volatiles such as water or organics. (g) Unit cell size: determined by X-ray powder diffraction. (h) API Gravity: The specific gravity of a petroleum feedstock / product compared to water as determined by ASTM D4052-11. (i) Acid site density: Temperature-programmed desorption (TPD) of isopropylamine (IPAm) to quantify the Bronsted acid site distribution of a material is described by Maesen and Hertzenberg, Journal of Catalysis 182, 270-273 (1999). (j) Acid site distribution and index factor: Acid site distribution determined by HD exchange FTIR, adapted from the description published by EJM Mensen, DG Poduval, DAJ Michel Ligthart, JA Robert van Veen, and MS Rigutto in J. Phys. Chem. CI, Vol. 114, pp. 8363-8374, 2010. Prior to FTIR measurements, the sample was heated at 400-450°C for 1 hour to obtain a 1×10 -5 The sample was heated under a vacuum of less than Torr. C6D6 was then added to the sample and equilibrated at 80 °C. Spectra were collected in the OH and OD stretching regions before and after C6D6 addition. The Brønsted acid site density was determined as the first high frequency OD (HF) at 2676 cm. -1 , the second high frequency OD (HF') is 2653 cm -1 , 2632 cm as the first low frequency OD (LF) -1 and 2620 cm -1 , and the second low frequency OD (LF') at 2600 cm -1 The acid site distribution index (ASDI) factor was determined by the following formula: ASDI = (HF' + LF') / (HF + LF); which represents the content of overactive sites in the zeolite sample.

[0037] <Hydrocracking catalyst composition> The HNPV SY-based hydrocracking catalyst used to hydrocracking the feedstock includes an HNPV SY zeolite, a support component, an amorphous silica-alumina (ASA) material, one or more metals, and optionally one or more promoters. The composition of the final HNPV SY catalyst, based on the bulk dry weight of the final HNPV SY catalyst, is set forth in Table 1 below. [Table 3]

[0038] The HNPV SY used to prepare the final HNPV SY-based hydrocracking catalyst described herein has an NPV (20 nm to 50 nm) of 0.15 to 0.6 cc / g and an acid site distribution index (ASDI) factor of between 0.02 and 0.12. In one subembodiment, the HNPV SY has an ADSI of between 0.06 and 0.12. In another subembodiment, the HNPV SY has an ASDI of between 0.08 and 0.11.

[0039] HNPV SY with unique, enhanced pore size distributions can be produced by conventional methods to introduce zeolitic porosity, including steam treatment, acid / base leaching, and dealumination or desilication by chemical treatment.

[0040] As will be appreciated by those skilled in the art, the manufacturing processes described herein for converting Y zeolite to HNPV SY will vary depending on the characteristics (e.g., particle size, crystal size, alkali content, silica-to-alumina ratio) of the particular Y zeolite utilized (i.e., the original manufacturer of the zeolite), the manufacturing equipment installed at the manufacturer's facility, where the manufacturer has typically developed significant body of knowledge regarding its operation and capabilities, and the stage of the manufacturing process at which the HNPV is introduced (e.g., as-made or after ammonium exchange). Thus, based on an understanding of the unique pore size distributions described herein, a manufacturer can then modify the operation of their equipment to convert stabilized Y zeolite to SY with the unique HNPV described herein.

[0041] Traditionally, as-prepared Y zeolite and SY (Y zeolite dealuminated to produce stable Y zeolite (SY)) can be converted to their HNPV counterparts by hydrothermal treatment using aqueous solutions having a pH between 1 and 6, typically at temperatures between 125 and 900°C, for times ranging from as short as 5 minutes to as long as 72 hours. Such treatments typically include post-steam chemical treatments using aqueous solutions containing species such as acids (HF, S2SO4, HNO3, AcOH), EDTA, or (NH4)2SiF6. Additionally, manufacturers use surfactants and pH control agents (e.g., NaOH) to control porosity formation. Pore formation methods are described in the published literature, such as those described in U.S. Patent Application Publication No. 2012 / 0275993 to Olson.

[0042] The ASDI factor is a measure of the concentration of superactive sites in a zeolite. The distribution of acid sites in a zeolite generally determines the catalytic activity and selectivity for a particular product to be refined. As the concentration of these acid sites increases, the feedstock undergoes more hydrocracking during commercial operation, resulting in the production of less valuable products such as naphtha and increased gas production (C1-C4). Therefore, it has been found that a decrease in the concentration of these superactive sites (a decrease in the ASDI factor) results in higher selectivity for the production of heavier middle distillate products.

[0043] The final hydrocracking catalyst produced using HNPV SY produces less gas and higher yields and quality of heavy middle distillate products compared to conventional hydrocracking catalysts containing conventional SY-based catalysts.

[0044] The HNPV SY zeolites useful in the hydrocracking catalysts described herein are characterized by the properties set forth in Table 2 below. [Table 4]

[0045] For each embodiment described herein, the HNPV SY hydrocracking catalyst support is selected from the group consisting of alumina, silica, zirconia, titanium oxide, magnesium oxide, thorium oxide, beryllium oxide, alumina-silica, alumina-titanium oxide, alumina-magnesium oxide, silica-magnesium oxide, silica-zirconia, silica-thorium oxide, silica-beryllium oxide, silica-titanium oxide, titanium oxide-zirconia, silica-alumina-zirconia, silica-alumina-thorium oxide, silica-alumina-titanium oxide, or silica-alumina-magnesium oxide, preferably alumina, silica-alumina, and combinations thereof.

[0046] The amount of support material in the final hydrocracking catalyst is from 10% to 45% by weight, based on the bulk dry weight of the hydrocracking catalyst. In one subembodiment, the amount of molecular sieve material in the final hydrocracking catalyst is from 15% to 35% by weight.

[0047] The amount of molecular sieve material in the final hydrocracking catalyst is from 0.1 wt. % to 75 wt. % based on the bulk dry weight of the hydrocracking catalyst. In one subembodiment, the amount of molecular sieve material in the final hydrocracking catalyst is from 5 wt. % to 60 wt. %.

[0048] In one embodiment, the HNPV SY zeolite has the properties set forth in Table 3 below. [Table 5]

[0049] In another embodiment, the HNPV SY zeolite has the properties set forth in Table 4 below. [Table 6]

[0050] As noted hereinabove, the final hydrocracking catalyst of the HNPV SY system described herein contains one or more metals. For each embodiment described herein, each metal utilized is selected from the group consisting of elements from Groups 6 and 8-10 of the Periodic Table, and mixtures thereof. In one subembodiment, each metal is selected from the group consisting of nickel (Ni), cobalt (Co), iron (Fe), chromium (Cr), molybdenum (Mo), tungsten (W), and mixtures thereof. In another subembodiment, the hydrocracking catalyst contains at least one metal from Group 6 and at least one metal selected from Groups 8-10 of the Periodic Table. Exemplary metal combinations include Ni / Mo / W, Ni / Mo, Ni / W, Co / Mo, Co / W, Co / W / Mo, and Ni / Co / W / Mo.

[0051] The total amount of metal oxide materials in the final hydrocracking catalyst is 15% to 55% by weight, based on the bulk dry weight of the hydrocracking catalyst. In one subembodiment, the hydrocracking catalyst contains 3% to 5% by weight nickel oxide and 15% to 35% by weight tungsten oxide, based on the bulk dry weight of the hydrocracking catalyst.

[0052] The final hydrocracking catalyst described herein may contain one or more promoters selected from the group consisting of phosphorus (P), boron (B), fluorine (F), silicon (Si), aluminum (Al), zinc (Zn), manganese (Mn), and mixtures thereof. The amount of promoter in the hydrocracking catalyst is from 0 to 10 wt. % based on the bulk dry weight of the hydrocracking catalyst. In one subembodiment, the amount of promoter in the hydrocracking catalyst is from 1 to 5 wt. % based on the bulk dry weight of the hydrocracking catalyst.

[0053] <Preparation of Hydrocracking Catalyst> Generally, the hydrocracking catalysts described herein are prepared by the following steps: (a) mixing and peptizing HNPV SY, ASA, and a carrier to form an extrudate base; (b) impregnating the base with a metal impregnation solution containing at least one metal; and (c) post-treating the metal-loaded extrudates, which comprises subjecting the extrudates to drying and calcination.

[0054] Prior to impregnation, the extrudate base is dried at a temperature between 90°C and 150°C (194°F and 302°F) for 1 to 12 hours and then calcined at a temperature between 350°C and 700°C (662°F and 1292°F) or higher.

[0055] The impregnation solution is prepared by dissolving the metal precursor in deionized water. The concentration of the solution is determined by the pore volume and metal loading of the support. During a typical impregnation, the support is exposed to the impregnation solution for 0.1 to 10 hours. After an additional 0.1 to 10 hours of soaking, the catalyst is dried at a temperature in the range of 38°C to 149°C (100°F to 300°F) or higher for 0.1 to 10 hours. The catalyst is further calcined in the presence of sufficient air flow at a temperature in the range of 316°C to 649°C (600°F to 1200°F) or higher for 0.1 to 10 hours.

[0056] In one embodiment, the impregnation solution further includes a modifier to promote deposition of at least one metal. Modifiers and methods of using such modifiers to prepare hydrocracking catalysts are disclosed in U.S. Patent Publication Nos. 20110000824 and 20110132807 to Zhan et al., published January 6, 2011, and June 9, 2011, respectively.

[0057] <Overview of Hydrocracking> The hydrocracking catalysts described herein are suitable for hydrotreating a variety of hydrocarbonaceous feedstocks, including, for example, visbroken gas oils, heavy coker gas oils, gas oils derived from resid hydrocracking or resid desulfurization, other pyrolysis oils, deasphalted oils, Fischer-Tropsch derived feedstocks, cycle oils from FCC units, heavy coal-derived distillates, coal gasification by-product tar, and heavy shale-derived oils, organic waste oils, such as those from pulp / paper mills or waste biomass pyrolysis units, and other disadvantaged feedstocks that would not normally result in the production of middle distillates using conventional one or two stage hydrocracking processes.

[0058] Table 5 below lists typical physical properties of feedstocks suitable for producing middle distillates using the catalysts described herein, and Table 6 lists typical hydrocracking process conditions. [Table 7] [Table 8]

[0059] Prior to introducing the feed to be hydrotreated, the catalyst is activated by contacting it with a petroleum liquid containing a sulfiding agent at a temperature of 200°F to 800°F (66°C to 482°C) for a period of 1 hour to 7 days under a H2-containing gas pressure of 100 kPa to 25,000 kPa. Suitable sulfiding agents include elemental sulfur, ammonium sulfide, ammonium polysulfide ([(NH4)2S] X ), ammonium thiosulfate ((NH4)2S2O3), sodium thiosulfate (Na2S2O3), thiourea CSN2H4, carbon disulfide, dimethyl disulfide (DMDS), dimethyl sulfide (DMS), dibutyl polysulfide (DBPS), mercaptans, tertiary butyl polysulfide (PSTB), tertiary nonyl polysulfide (PSTN), and ammonium hydrosulfide.

[0060] As discussed above, the final hydrocracking catalyst using the novel HNPV SY component exhibits improved hydrogen efficiency and higher yields and quality of heavy middle distillate products compared to conventional hydrocracking catalysts containing conventional SY.

[0061] Depending on the feedstock, the target product slate, and the amount of available hydrogen, the catalysts described herein can be used alone or in combination with other conventional hydrocracking catalysts.

[0062] In one embodiment, the catalyst is disposed in one or more fixed beds in a single stage hydrocracking unit, with or without recycle (once-through). Optionally, the single stage hydrocracking unit may utilize multiple single stage units operated in parallel.

[0063] In another embodiment, the catalyst is arranged in one or more beds and units in a two-stage hydrocracking unit, with or without intermediate stage separation and with or without recycle. The two-stage hydrocracking unit can be operated using a full conversion configuration, meaning that all of the hydrotreating and hydrocracking is accomplished within the hydrocracking loop with recycle. In this embodiment, one or more distillation units can be utilized within the hydrocracking loop to remove products prior to the second stage hydrocracking step or before recycling the distillation bottoms back to the first and / or second stage.

[0064] The two-stage hydrocracking unit can also be operated in a partial conversion configuration, meaning that one or more distillation units are placed within the hydrocracking loop to remove one or more of the incoming streams for further hydroprocessing. Operating the hydrocracking unit in this manner allows the refinery to hydrotreat highly unfavorable feedstocks by allowing undesirable feed components, such as polynuclear aromatics, nitrogen and sulfur species (which deactivate the hydrogenation catalyst), to exit the hydrocracking loop for processing by equipment better suited to handle these components, such as an FCC unit.

[0065] In one embodiment, the two stage hydrocracking configuration is well suited to producing at least one middle distillate and heavy vacuum gas fluidized catalytic cracking feedstock (HVGO FCC), although the catalyst is used in a first stage and optionally a second stage of partial conversion, according to the following steps: (a) hydrocracking a hydrocarbonaceous feedstock to produce a first stage hydrocracking effluent; (b) distilling the hydrocracking feedstock by atmospheric distillation to form at least one middle distillate fraction and an atmospheric bottoms fraction; (c) further distilling the atmospheric bottoms fraction by vacuum distillation to form a side cut vacuum gas oil fraction and a heavy vacuum gas oil FCC feedstock; (d) hydrocracking the side cut vacuum gas oil fraction to form a second stage hydrocracked effluent; and (e) combining said second-stage hydrocracking effluent with said first-stage hydrocracking effluent.

[0066] The above refinery configuration has several advantages over conventional two-stage hydrocracking schemes. First, in this configuration, the first-stage catalyst and operating conditions are selected to produce an HVGO FCC stream with only the minimum feed quality required to produce an FCC product that meets established commercial specifications. This contrasts with conventional two-stage hydrocracking schemes, where the first-stage hydrocracking unit is operated at the severe conditions necessary to maximize fraction yield, thereby requiring units capable of operating at more severe conditions, which require more hydrogen and shorten catalyst life.

[0067] Second, the sidecut VGO sent to the second-stage hydrocracking unit is cleaner and easier to hydrocrack than conventional second-stage hydrocracking feeds. Therefore, higher quality middle distillate products can be achieved using a smaller volume of second-stage hydrocracking catalyst, which allows for the construction of smaller hydrocracker reactors and lower hydrogen consumption. The second-stage hydrocracking unit configuration reduces construction costs, catalyst loading costs, and operating costs.

[0068] <product> The process of the present invention is particularly useful for producing middle distillate fractions boiling in the range of about 380 to 700°F (193 to 371°C). At least 75% by volume, preferably at least 85% by volume, of the components of the middle distillate have a normal boiling point above 380°F (193°C). At least about 75% by volume, preferably at least 85% by volume, of the components of the middle distillate have a normal boiling point below 700°F (371°C).

[0069] Additionally, gasoline or naphtha can be produced by the process of the present invention. Gasoline or naphtha typically boils below 380°F (193°C), but above the boiling point of C5 hydrocarbons, and sometimes refers to a boiling range from the boiling point of C5 hydrocarbons to 400°F (204°C). The boiling ranges of the various product fractions recovered at any particular refinery will vary with factors such as the characteristics of the crude oil source, local refinery markets, and product prices.

[0070] The following examples serve to illustrate, but not limit, the present invention. [Example]

[0071] Example 1 <Preparation of Hydrocracking Catalyst> A conventional USY-based hydrocracking catalyst was prepared by the following procedure: 56.4 wt. % USY as described herein, 21 wt. % amorphous silicoaluminate powder (Sasol's Siral-30), and 22.6 wt. % pseudoboehmite alumina powder (Sasol's CATAPAL C1) were thoroughly mixed. To this mixture was added a diluted aqueous HNO acid solution (3 wt. %) to form an extrudable paste. The paste was extruded into 1 / 16" (inch) asymmetric square shapes and dried at 248°F (120°C) for 1 hour. The dried extrudates were calcined at 1100°F (593°C) for 1 hour while purging with excess dry air and then cooled to room temperature.

[0072] Impregnation with Ni and W was carried out using a solution containing ammonium metatungstate and nickel nitrate at concentrations equivalent to a target metal loading of 3.8 wt.% NiO and 25.3 wt.% WO, based on the bulk dry weight of the final catalyst. The extrudates were then dried at 270°F (132°C) for 1 hour. The dried extrudates were then calcined at 950°F (510°C) for 1 hour with an excess dry air purge and cooled to room temperature.

[0073] A final HNPV USY-based hydrocracking catalyst was prepared following the procedure described in Example 1, except that 56.4 wt % HNPV USY was used instead of conventional USY.

[0074] The physical properties of the conventional and HNPV USY materials, as well as their acid site distributions after HD exchange, are shown in Tables 7 and 8 below.

[0075] Prior to incorporation into the final catalyst, the conventional USY and HNPV USY zeolites were analyzed by transmission electron microscopy (TEM). TEM images of the conventional USY and HNPV USY are shown in Figures 1 and 2, respectively.

[0076] Furthermore, the pore size distributions of the conventional USY and HNPV zeolites were measured, and plots of the pore size distributions of the two zeolites are shown in Figure 3.

[0077] OD acidity was determined by the amount of bridging hydroxyl groups exchanged with deuterated benzene at 80° C., which is measured by FT-IR. [Table 9] [Table 10]

[0078] Example 2 <Hydrocracking performance> Conventional USY and HNPV USY catalysts were used to process typical Middle Eastern VGO. Feed characteristics are shown in Table 11. The experiments were conducted in a pilot plant unit operated at 2300 psig total pressure and 1.0 to 2.2 LHSV. The feed passed through a catalyst bed packed with hydrotreating catalyst before entering the hydrocracking zone. Prior to feed introduction, the catalyst was activated with either DMDS (vapor phase sulfiding) or diesel feed with DMDS (liquid phase sulfiding).

[0079] The feed quality and test results are shown below in Tables 9 and 10. As shown in Table 10, the HNPV USY-based catalyst shows improved activity and selectivity to distillate products. Diesel yield increased by 2.6%, and yields to gas and naphtha decreased.

[0080] Additionally, the HNPV USY-based catalyst produced less undesirable gases and light ends (C4- and C5-180°F) than the conventional USY catalyst. Additionally, the HNPV USY-based catalyst produced higher yields of desirable middle distillates (380 to 700°F) than the conventional USY catalyst. [Table 11] [Table 12]

[0081] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made thereto without departing from the spirit and scope of the invention.

Claims

1. A carrier; an amorphous silica-alumina material; a stabilized Y zeolite having an acid site distribution index factor between 0.02 and 0.12; At least one metal selected from the group consisting of elements of Groups 6 and 8 to 10 of the Periodic Table; A hydrocracking catalyst comprising:

2. 2. The hydrocracking catalyst of claim 1, wherein the stabilized Y zeolite is a high nanopore volume stabilized Y zeolite having a nanopore volume of 0.15 to 0.6 cc / g in the range of 20 nm to 50 nm.

3. 3. The hydrocracking catalyst of claim 2, wherein 20 to 30% of the nanopore volume is in the range of 8 nm to 20 nm.

4. 3. The hydrocracking catalyst of claim 2, wherein 40 to 60% of the nanopore volume is in the range of 20 nm to 50 nm.

5. 3. The hydrocracking catalyst of claim 2, wherein 15 to 25% of the nanopore volume is greater than 50 nm.

6. 10. The hydrocracking catalyst of claim 1, wherein the high nanopore volume stabilized Y zeolite has an acid site distribution index factor between 0.06 and 0.

12.

7. 10. The hydrocracking catalyst of claim 1, wherein the high nanopore volume stabilized Y zeolite has an acid site distribution index factor between 0.08 and 0.

11.

8. 1. A method for hydrocracking a hydrocarbonaceous feedstock comprising contacting the hydrocarbonaceous feedstock with a hydrocracking catalyst under hydrocracking conditions to produce a hydrocracked effluent; The hydrocracking catalyst is A carrier; an amorphous silica-alumina material; a stabilized Y zeolite having an acid site distribution index factor between 0.02 and 0.12; At least one metal selected from the group consisting of elements of Groups 6 and 8 to 10 of the Periodic Table; A method comprising:

9. 9. The method of claim 8, wherein the stabilized Y zeolite is a high nanopore volume stabilized Y zeolite having a nanopore volume of 0.15 to 0.6 cc / g in the range of 20 nm to 50 nm.

10. 10. The method of claim 9, wherein 20 to 30% of the nanopore volume is in the range of 8 nm to 20 nm.

11. 10. The method of claim 9, wherein 40 to 60% of the nanopore volume is in the range of 20 nm to 50 nm.

12. 10. The method of claim 9, wherein 15 to 25% of the nanopore volume is greater than 50 nm.

13. 9. The method of claim 8, wherein the high nanopore volume stabilized Y zeolite has an acid site distribution index factor between 0.06 and 0.

12.

14. 9. The method of claim 8, wherein the high nanopore volume stabilized Y zeolite has an acid site distribution index factor between 0.08 and 0.

11.

15. 9. The process of claim 8, wherein the hydrocracked effluent is a heavy middle distillate product in the range of 380 to 700°F (193 to 371°C).

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