Methods and systems for mixing catalyst precursors into heavy oils using high boiling hydrocarbon diluents

Abstract

Systems and methods for mixing a catalyst precursor into a heavy oil using a high boiling hydrocarbon diluent to form a diluted precursor mixture that is mixed with a heavy oil feedstock to form a modulated feedstock that is then heated to decompose the precursor and form dispersed metal sulfide catalyst particles in situ. Because the temperature of the high boiling hydrocarbon diluent is typically higher than the decomposition temperature of the catalyst precursor, it is first fed through a cooler to reduce its temperature, thereby avoiding premature decomposition of the catalyst precursor. The high-boiling hydrocarbon diluent may include a portion of a heavy oil feedstock, a portion of a modulated feedstock, vacuum column substrate product, or other high-boiling hydrocarbon material having a boiling point above 524 DEG C. A portion of the diluent may optionally include a medium boiling point hydrocarbon material having a boiling point below 524 DEG C.

Description

Technical Field

[0001] The present invention relates to a method and system for mixing a catalyst precursor into a heavy oil feedstock prior to hydroprocessing using a high boiling point hydrocarbon as a diluent. Background Art

[0002] The conversion of heavy oil into useful end products involves a great deal of processing, such as lowering the boiling point of the heavy oil, increasing the hydrogen to carbon ratio, and removing impurities, such as metals, sulfur, nitrogen, and coke precursors. Examples of hydrocracking processes using conventional heterogeneous catalysts to upgrade atmospheric bottoms and / or vacuum bottoms include fixed bed hydroprocessing, ebullating bed hydroprocessing, and moving bed hydroprocessing. Hydrocracking can also be carried out in a slurry bed reactor using a homogeneous catalyst.

[0003] The demand for more effectively utilizing low-quality heavy oil raw materials and extracting fuel value therefrom is increasing day by day. The characteristic of low-quality raw materials is to include relatively large amounts of hydrocarbons with nominal boiling points of 524°C (975°F) or above. They also contain relatively high concentrations of asphaltenes, sulfur, nitrogen and metals. The high boiling fractions derived from these low-quality raw materials usually have high molecular weights (usually represented by higher density and viscosity) and / or low hydrogen / carbon ratios, which are related to the presence of high concentrations of undesirable components (including asphaltenes and carbon residues). Asphaltenes and carbon residues are difficult to process and usually cause fouling of conventional catalysts and hydroconversion equipment because they cause the formation of coke and deposits.

[0004] Low-quality heavy oil feedstocks contain high concentrations of asphaltenes, carbon residues, sulfur, nitrogen, and metals. Examples include heavy crude oil, oil sands bitumen, and the residues left over from conventional refining processes. Residues (or "resids") may refer to atmospheric bottoms and vacuum bottoms. The boiling point of atmospheric bottoms is at least 343°C (650°F), but it is understood that the distillation point may vary from refinery to refinery, up to 380°C (716°F). The boiling point of vacuum bottoms (also called "residual oil bitumen" or "vacuum residue") is at least 524°C (975°F), but it is understood that the distillation point may vary from refinery to refinery, up to 538°C (1000°F) or even 565°C (1050°F).

[0005] As a comparison, Alberta light crude contains about 9 vol% vacuum residue, while Lloydminster heavy oil contains about 41 vol% vacuum residue, Cold Lake bitumen contains about 50 vol% vacuum residue, and Athabasca bitumen contains about 51 vol% vacuum residue. As a further comparison, relatively light oils from the North Sea region, such as DanskBlend, contain only about 15 vol% vacuum residue, while lower quality European oils, such as Ural, contain more than 30 vol% vacuum residue, and oils such as Arab Medium are even higher, containing about 40 vol% vacuum residue.

[0006] In a given ebullated-bed system, the production rate of conversion products is typically limited by fouling. When attempts are made to increase the production of conversion products beyond certain practical limits, the fouling rates of mixers, heat exchangers, filters, and other process equipment become too rapid, requiring more frequent shutdowns for maintenance and cleaning. Refinery operators typically relate observed equipment fouling rates to measurements of deposit production and derive an operating deposit limit, above which the refinery will avoid operating an ebullated-bed hydrocracking unit. Thus, deposit generation and fouling of the equipment place a practical upper limit on conversion and conversion product production rates. These problems are exacerbated when lower quality heavy oil feedstocks are used.

[0007] Ebullating bed reactors utilizing dual catalyst systems consisting of a heterogeneous catalyst and a dispersed (e.g., metal sulfide) catalyst have been used to reduce equipment fouling and / or allow for increased production rates of converted products. The success or failure of dual catalyst systems depends on multiple variables, including the particle size of the dispersed catalyst, which is a result of how it is formed. In the case of a metal sulfide catalyst formed from a catalyst precursor, the size and activity of the resulting catalyst is primarily based on the degree of dispersion thereof in the heavy oil prior to thermal decomposition to form the active catalyst. Unless the catalyst precursor is fully dispersed in the heavy oil prior to thermal decomposition, the resulting metal sulfide catalyst particles formed in the heavy oil feedstock will have low catalytic activity and may actually result in more equipment fouling, thereby reducing its effectiveness as a catalyst.

[0008] When using a dispersed catalyst to enhance the performance of an ebullating bed hydroprocessing system, it is preferred to first prepare a diluted precursor mixture which is then mixed with the heavy oil feedstock. This is prepared by mixing the catalyst precursor with a hydrocarbon diluent, which is selected based on availability, cost, suitability for addition to the hydroprocessing process, and ability to dissolve the precursor. Such a diluted precursor mixture is more easily dispersed in the bulk of the heavy oil feedstock than directly mixing the precursor with the heavy oil feedstock. By simply adding the catalyst precursor to the heavy oil feed, it may be difficult to adequately mix the catalyst precursor, which can produce a poorly mixed material that may result in the formation of undesirably large or agglomerated catalyst particles when the dispersed catalyst is subsequently activated by heating the feedstock mixture.

[0009] Some people use low boiling point and medium boiling point hydrocarbons as diluents for catalyst precursors to form a diluted precursor mixture, which is then mixed into the heavy oil feedstock. Materials such as start-up diesel, vacuum gas oil, atmospheric gas oil, decant oil, and cycle oil are suitable medium boiling point diluents. These materials have nominal boiling points in the range of 200°C to 524°C and have good solubility for dispersed catalyst precursors. In addition, they are usually processed and / or stored in a temperature range that makes them suitable for use as diluents without further processing. This is because it is advantageous to use a diluent at a temperature below the decomposition temperature of the catalyst precursor so that the precursor can be completely dissolved and dispersed before the precursor significantly decomposes and the activation of the dispersed metal sulfide catalyst particles occurs.

[0010] However, in some hydroconversion facilities, such materials are either unavailable or unsuitable for this purpose. For example, a hydroconversion unit may be operating at or near the upper limit of its capacity to handle heavy feedstocks. Adding a mid-boiling diluent to the process would displace a portion of the heavy feedstock, thereby reducing the effective capacity of the system to handle the heavy feedstock below the desired level. Another reason is that available mid-boiling materials (which may be conversion products of the hydroconversion process) may have sufficient commercial sale value, or value to produce a saleable product, that they are practically too expensive to be used as diluents. Potential mid-boiling materials may need to be used as feeds or intermediates for other processing systems in the commercial complex, making them unsuitable for use as diluents.

[0011] Alternatively, the use of medium boiling hydrocarbon diluents may lead to processing problems. For example, the plant feedstock may already contain limited amounts of medium boiling materials. Medium boiling components in the plant feed can lead to the formation of deposits, which can be exacerbated by adding additional amounts of medium boiling hydrocarbons to the feedstock via a diluted precursor mixture. There may be compatibility issues between heavy oil feedstocks and readily available sources of medium boiling diluents, which can lead to deposits and more severe fouling in the hydroprocessing unit. Summary of the invention

[0012] Disclosed herein are methods and systems that are specifically configured to mix a catalyst precursor into a high boiling hydrocarbon diluent to form a catalyst precursor mixture, and then mix the catalyst precursor mixture with a heavy oil feedstock to form a conditioned feedstock in preparation for hydroprocessing the heavy oil using one or more hydroprocessing reactors. The conditioned feedstock can be heated to thermally decompose the catalyst precursor and form dispersed metal sulfide catalyst particles that have high catalytic activity and promote beneficial upgrading reactions when hydroprocessing the heavy oil.

[0013] The disclosed methods and systems provide for the efficient use of dispersed catalysts in ebullated-bed hydroconversion systems when medium-boiling point materials are not available or are not advantageous as diluents to prepare a diluted precursor mixture.

[0014] The high boiling hydrocarbon diluent may comprise one or more high boiling hydrocarbons, such as vacuum residue, vacuum bottoms, other heavy oil feedstocks, deasphalted heavy oil, and / or a side stream of a conditioned heavy oil feedstock formed using the disclosed method and system. The high boiling hydrocarbons typically have a nominal boiling point greater than 524° C. The high boiling hydrocarbon diluent may optionally contain or be mixed with medium boiling hydrocarbons, such as start-up diesel, vacuum gas oil, atmospheric gas oil, decant oil, cycle oil, or other hydrocarbons having a nominal boiling point in the range of about 200° C. to 524° C.

[0015] In some embodiments, hydrocarbon diluent is made up of high boiling point material completely.In alternative embodiments, a part of hydrocarbon diluent can comprise medium boiling point material, makes diluent be the mixture of high boiling point hydrocarbon and medium boiling point hydrocarbon.High boiling point hydrocarbon diluent preferably contains at least 25 volume %, at least 50 volume %, at least 70 volume %, at least 80 volume %, at least 90 volume % or at least 95 volume % of one or more high boiling point hydrocarbons and is less than 75 volume %, less than 50 volume %, less than 30 volume %, less than 20 volume %, less than 10 volume % or less than 5 volume % of one or more medium boiling point hydrocarbons.In some embodiments, high boiling point hydrocarbon diluent is made up of one or more high boiling point hydrocarbons substantially, and one or more medium boiling point hydrocarbons are omitted substantially.

[0016] Consistent with the foregoing, the high boiling hydrocarbon diluent contains one or more high boiling hydrocarbons having a boiling point of at least 524°C and optionally one or more medium boiling hydrocarbons such that the diluent has a nominal boiling point of at least 350°C, preferably a nominal boiling point of at least 400°C, more preferably a nominal boiling point of at least 450°C, and most preferably a nominal boiling point of at least 500°C, such as a nominal boiling point of at least 524°C. It should be noted that the defined cut point for use as "vacuum residue" or "vacuum tower bottoms" may vary between refineries, with some refineries using a cut point of 524°C, others using a cut point of 540°C, and still others using a cut point of 565°C. When the cut point of the vacuum residue is above 524°C, it may be advantageous to add medium boiling hydrocarbons to reduce the viscosity of the high boiling hydrocarbon diluent used to form the catalyst precursor mixture.

[0017] Preferred catalyst precursors are oil soluble and have a decomposition temperature above which they will decompose. It is therefore advantageous for the temperature of the hydrocarbon diluent to be below the decomposition temperature of the catalyst precursor to prevent premature decomposition and the formation of agglomerated catalyst particles having low activity. Unfortunately, available high boiling hydrocarbons are typically kept at relatively high temperatures of up to 300°C, in large part to reduce the viscosity of the high boiling materials, thereby making them easier to pump and process.

[0018] The temperatures at which high boiling hydrocarbons are typically maintained are generally too high for using these materials as catalyst precursor diluents. If the high boiling hydrocarbons were mixed directly with the catalyst precursor at its normal storage temperature, they would cause premature decomposition of the precursor and cause agglomeration of the dispersed catalyst in the catalyst precursor mixture, which would greatly reduce the performance of the dispersed catalyst when used to hydroprocess a heavy oil feedstock.

[0019] To address this problem, the disclosed methods and systems utilize a cooler (e.g., a heat exchanger) that controls the temperature of the high boiling hydrocarbon diluent. The selection and control of this temperature is critical because it must be high enough to allow the high boiling hydrocarbon to have a low enough viscosity so that it can flow and mix with the catalyst precursor, but low enough to avoid premature decomposition and undesirable agglomeration of the dispersed catalyst particles. In some embodiments, the high boiling hydrocarbon diluent is preferably cooled to a temperature in the range of about 75°C to about 150°C, more preferably in the range of about 75°C to about 125°C, and most preferably in the range of about 75°C to about 95°C.

[0020] The process of cooling the high boiling hydrocarbon diluent may include adding one or more medium boiling hydrocarbons to the high boiling material. The medium boiling hydrocarbons are typically stored or maintained at a temperature below 150° C., preferably below 125° C., and more preferably below 95° C. Thus, the cooling process may include the step of cooling the high boiling hydrocarbon diluent using a cooler, wherein some of the cooling is caused by mixing the already cooler medium boiling hydrocarbons.

[0021] The high boiling hydrocarbon diluent may be used in an amount ranging from 0.1% to 10% by volume, or 0.5% to 5% by volume of the total feedstock entering the hydroprocessing unit. Sources of high boiling diluents (e.g., heavy oil feedstock, conditioned heavy oil feedstock, vacuum residue, deasphalted heavy oil, and vacuum bottoms) may be used alone at 0.1% to 10%, or 0.5% to 5% of the total heavy oil feedstock, or they may be used in any combination of 0.1% to 10%, or 0.5% to 5% of the total heavy oil feedstock. Such a source of high boiling hydrocarbon diluent may optionally be combined with one or more medium boiling hydrocarbons alone, or with one or more sources of heavy boiling diluents in any combination, the total amount of which is 0.1% to 10%, or 0.5% to 5% of the total heavy oil feedstock.

[0022] Example methods of mixing the catalyst precursor into the heavy oil feedstock include:

[0023] (1) providing a catalyst precursor having a decomposition temperature;

[0024] (2) providing a high boiling hydrocarbon diluent consisting of one or more high boiling hydrocarbons and optionally one or more medium boiling hydrocarbons, the high boiling hydrocarbon diluent initially having a temperature above the decomposition temperature of the catalyst precursor;

[0025] (3) cooling the high boiling point hydrocarbon diluent to a temperature below the decomposition temperature of the catalyst precursor;

[0026] (4) mixing the catalyst precursor with a high boiling point hydrocarbon diluent to form a diluted precursor mixture; and

[0027] (5) mixing the diluted precursor mixture with a heavy oil feedstock to form a conditioned feedstock;

[0028] Example systems for mixing catalyst precursor into heavy oil feedstock include:

[0029] (1) a catalyst precursor supply line, which provides a catalyst precursor having a temperature lower than a decomposition temperature of the catalyst precursor;

[0030] (2) at least one diluent supply line, which provides a high boiling point hydrocarbon diluent composed of one or more high boiling point hydrocarbons and optionally one or more medium boiling point hydrocarbons, the diluent supply line providing the high boiling point hydrocarbon diluent having an initial temperature above the decomposition temperature of the catalyst precursor;

[0031] (3) at least one cooler configured to cool the high boiling point hydrocarbon diluent to a temperature below the decomposition temperature of the catalyst precursor;

[0032] (4) at least one premix mixer configured to receive the catalyst precursor and mix it with a high boiling point hydrocarbon to form a diluted precursor mixture; and

[0033] (5) At least one mixer configured to mix the diluted precursor mixture with the heavy oil feedstock to form a conditioned feedstock.

[0034] In some embodiments, cooling of the high boiling hydrocarbon diluent is performed solely by one or more coolers, such as one or more heat exchangers. In other embodiments, cooling the high boiling hydrocarbon diluent comprises adding a medium boiling hydrocarbon whose temperature is already below the decomposition temperature of the catalyst precursor.

[0035] The method and system may include a plurality of different mixers and / or different types of mixers, such as a static inline mixer, a high shear mixer, a surge tank with a pump, and a pump for feeding the heavy oil feedstock to the hydroprocessing reactor.

[0036] In some embodiments, a portion of the heavy oil feedstock may be used as a diluent to form a diluted precursor mixture. The heavy oil feedstock, when used as a diluent, may advantageously be passed through a heat exchanger to reduce its temperature prior to mixing with the catalyst precursor.

[0037] In other embodiments, a portion of the conditioned feedstock may be used as a diluent to form a diluted precursor mixture. The conditioned feedstock, when used as a diluent, is advantageously passed through a heat exchanger to reduce its temperature prior to mixing with the catalyst precursor.

[0038] In other embodiments, the vacuum bottoms may be used as a diluent to form a diluted precursor mixture. The vacuum bottoms product, when used as a diluent, is advantageously passed through a heat exchanger to reduce its temperature prior to mixing with the catalyst precursor.

[0039] In other embodiments, deasphalted heavy oil may be used as a diluent to form the diluted precursor mixture. Deasphalted heavy oil, when used as a diluent, is advantageously passed through a heat exchanger to reduce its temperature prior to mixing with the catalyst precursor.

[0040] The catalyst precursor is preferably oil soluble and has a decomposition temperature in the range of about 100°C (212°F) to about 350°C (662°F), or about 150°C (302°F) to about 300°C (572°F), or about 175°C (347°F) to about 250°C (482°F). Exemplary catalyst precursors include organometallic complexes or compounds, more specifically oil soluble compounds or complexes of transition metals and organic acids, having a decomposition temperature or decomposition temperature range high enough to avoid substantial decomposition when mixed with a heavy oil feedstock under suitable mixing conditions. When the catalyst precursor is mixed with a hydrocarbon oil diluent, it is advantageous to maintain the diluent below the temperature at which the catalyst precursor undergoes significant decomposition. One skilled in the art can select a mixing temperature profile that allows for thorough mixing of the selected precursor composition without significant decomposition prior to forming dispersed metal sulfide catalyst particles in situ.

[0041] The conditioned feedstock may be passed through a heater prior to entering the hydroprocessing reactor to decompose at least a portion of the catalyst precursor and form dispersed metal sulfide catalyst particles in situ in the heavy oil feedstock. For example, the conditioned feedstock may be removed from a buffer tank (e.g., a warm buffer tank) and passed through a heater. Alternatively, or in addition, at least a portion of the conditioned feedstock may be heated within the hydroprocessing reactor itself to decompose at least a portion of the catalyst precursor and form dispersed metal sulfide catalyst particles in situ in the heavy oil feedstock. It has been found that preheating the conditioned feedstock upstream of the hydroprocessing reactor produces a more active dispersed catalyst.

[0042] In some embodiments, the dispersed metal sulfide catalyst particles are less than 1 μm in size, or less than about 500 nm in size, or less than about 250 nm in size, or less than about 100 nm in size, or less than about 50 nm in size, or less than about 25 nm in size, or less than about 10 nm in size, or less than about 5 nm in size.

[0043] In some embodiments, the heavy oil feedstock with dispersed metal sulfide catalyst particles formed in situ can be hydroprocessed under hydroprocessing conditions, wherein the dispersed metal sulfide catalyst promotes beneficial hydrogenation and other upgrading reactions in the presence of heat and hydrogen. The hydroprocessing can be carried out by one or more hydroprocessing reactors selected from a slurry phase reactor, an ebullating bed reactor, and a fixed bed reactor.

[0044] For example, the hydroprocessing of heavy oil can be carried out using one or more ebullated bed reactors that utilize a dispersed metal sulfide catalyst in combination with a heterogeneous ebullated bed catalyst to produce upgraded heavy oil. Instead of or in addition to one or more ebullated bed reactors, the hydroprocessing of heavy oil can also be carried out using one or more slurry phase reactors that utilize a dispersed metal sulfide catalyst as the sole catalyst or in combination with a conventional slurry catalyst and / or one or more fixed bed reactors that utilize a dispersed metal sulfide catalyst in combination with a heterogeneous fixed bed catalyst.

[0045] After the heavy oil is hydrotreated, the upgraded heavy oil can be separated into one or more low boiling hydrocarbon fractions and one or more liquid hydrocarbon fractions. For example, one or more thermal separation units, interstage separators that cause pressure drop, atmospheric distillation columns, or vacuum distillation columns can be used to separate the upgraded heavy oil.

[0046] These and other advantages and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to further illustrate the above and other advantages and features of the present invention, the present invention will be described in more detail with reference to the specific embodiments of the present invention shown in the accompanying drawings. It should be understood that these drawings generally depict only typical embodiments of the present invention and should not be considered as limiting the scope thereof. The present invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

[0048] Figure 1 The hypothetical molecular structure of asphaltenes is depicted;

[0049] Figure 2 An exemplary ebullated-bed hydroprocessing system using a dual catalyst system that can be used to hydroprocess heavy oil is schematically illustrated;

[0050] Figure 3A schematically illustrates an exemplary ebullated bed reactor and a separator unit for separating volatile materials from non-volatile materials;

[0051] Figure 3B Schematically illustrates an exemplary slurry phase reactor and a separator unit for separating volatile materials from non-volatile materials;

[0052] Figure 3C An exemplary hydroprocessing system is schematically illustrated, the system comprising a slurry phase reactor, a separator unit to separate volatile materials from non-volatile materials, and a fixed bed reactor for further hydroprocessing the non-volatile materials;

[0053] Figure 4A An exemplary ebullated-bed hydroprocessing system having multiple ebullated-bed reactors and other processing equipment is schematically illustrated.

[0054] Figure 4B An exemplary ebullated bed hydroprocessing system is schematically illustrated, which includes a Figure 4A A plurality of ebullating bed reactors, and an interstage separator between two reactors;

[0055] Figure 5 Schematically illustrates an exemplary mixing system for mixing a catalyst precursor into a heavy oil feedstock using a high boiling hydrocarbon diluent;

[0056] Figure 6 is a flow chart schematically illustrating an exemplary method for preparing a conditioned heavy oil feedstock using a catalyst precursor and a high boiling point hydrocarbon diluent;

[0057] Figure 7A-7B schematically illustrates an exemplary system for preparing a conditioned heavy oil feedstock using a catalyst precursor and a high boiling point hydrocarbon diluent; and

[0058] Figures 8A-8B Other exemplary mixing systems having parallel mixing lines and bypass lines for preparing a conditioned heavy oil feedstock using a catalyst precursor and a high boiling hydrocarbon diluent are schematically illustrated. DETAILED DESCRIPTION

[0059] 1. Introduction

[0060] Disclosed herein are methods and systems that are specifically configured to mix a catalyst precursor into a high boiling hydrocarbon diluent to form a catalyst precursor mixture, and then mix the catalyst precursor mixture with a heavy oil feedstock to form a conditioned feedstock in preparation for hydroprocessing the heavy oil using one or more hydroprocessing reactors. The disclosed methods and systems provide for the efficient use of dispersed catalysts in an ebullating bed, fixed bed, or slurry hydroconversion system when medium boiling point materials are not available or are not advantageous as diluents to prepare the diluted precursor mixture.

[0061] The high boiling hydrocarbon diluent may comprise one or more high boiling hydrocarbons, such as vacuum residue, vacuum bottoms, other heavy oil feedstocks, deasphalted heavy oil, and / or a side stream of a conditioned heavy oil feedstock formed using the disclosed method and system. The high boiling hydrocarbons typically have a nominal boiling point greater than 524° C. The high boiling hydrocarbon diluent may optionally contain or be mixed with medium boiling hydrocarbons, such as start-up diesel, vacuum gas oil, atmospheric gas oil, decant oil, cycle oil, or other hydrocarbons having a nominal boiling point in the range of about 200° C. to 524° C.

[0062] Preferred catalyst precursors are oil soluble and have a decomposition temperature above which they will decompose. Unfortunately, high boiling hydrocarbons are often kept at temperatures above the decomposition temperature of the preferred catalysts to reduce their viscosity so that they can be easily pumped and processed.

[0063] The disclosed methods and systems utilize a chiller that controls the temperature of the high boiling hydrocarbon diluent to prevent significant decomposition of the catalyst precursor when forming the catalyst precursor mixture. In some embodiments, the high boiling hydrocarbon diluent is cooled to a temperature in the range of about 75°C to about 150°C, or about 75°C to about 125°C, and most or about 75°C to about 95°C.

[0064] In some embodiments, cooling of the high boiling hydrocarbon diluent is performed solely by one or more coolers, such as one or more heat exchangers. In other embodiments, cooling the high boiling hydrocarbon diluent comprises adding a medium boiling hydrocarbon whose temperature is already below the decomposition temperature of the catalyst precursor.

[0065] In some embodiments, a portion of the heavy oil feedstock can be used as a diluent to form a diluted precursor mixture. In other embodiments, a portion of the conditioned feedstock can be used as a diluent to form a diluted precursor mixture. In other embodiments, vacuum bottoms can be used as a diluent to form a diluted precursor mixture. In other embodiments, deasphalted heavy oil can be used as a diluent to form a diluted precursor mixture. When such a material is used as a diluent, it is advantageously passed through a heat exchanger before mixing with the catalyst precursor to reduce its temperature.

[0066] II. Definitions

[0067] "Asphaltenes" and "asphaltenes" refer to materials in heavy oil that are insoluble in paraffinic solvents such as propane, butane, pentane, hexane and heptane. Asphaltenes can include sheets of fused ring compounds held together by heteroatoms such as sulfur, nitrogen, oxygen and metals. Asphaltenes broadly include a variety of complex compounds with 80 to 1200 carbon atoms, with the major molecular weights ranging from 1200 to 16900 as determined by solution techniques. About 80-90% of the metals in crude oil are contained in the asphaltene fraction, which, combined with a higher concentration of non-metallic heteroatoms, makes the asphaltene molecules more hydrophilic and less hydrophobic than other hydrocarbons in heavy oil residue.

[0068] A hypothetical asphaltene molecular structure developed by A.G.Bridge and colleagues at Chevron Figure 1As shown. Asphaltenes are often defined based on the results of an insolubles analysis, and more than one definition of asphaltenes may be used. Specifically, a common definition of asphaltenes is heptane insolubles minus toluene insolubles (i.e., asphaltenes are soluble in toluene; sediments and residues that are insoluble in toluene are not counted as asphaltenes). Asphaltenes defined in this manner may be referred to as "C7 asphaltenes." Another definition is to measure pentane insolubles minus toluene insolubles, commonly referred to as "C5 asphaltenes." In the examples of the present invention, the C7 asphaltenes definition is used, but the C5 asphaltenes definition may be easily replaced.

[0069] "Fouling" refers to the formation of undesirable phases (foulants) that interfere with processing. Foulants are typically carbonaceous materials or solids (e.g., sediments) that settle and accumulate within process equipment. Equipment fouling can result in production losses due to equipment downtime, reduced equipment performance, increased energy consumption due to the insulating effects of fouling deposits in heat exchangers or heaters, increased equipment cleaning and maintenance costs, reduced fractionator efficiency, and reduced heterogeneous catalyst reactivity. Hydroprocessing equipment, such as blending lines, require periodic maintenance to remove deposits and other foulants.

[0070] The "equipment fouling rate" of a hydrocracking reactor can be determined by at least one of the following: (i) the frequency of required heat exchanger cleaning; (ii) the frequency of switching to a backup heat exchanger; (iii) the frequency of filter replacement; (iv) the frequency of strainer cleaning or replacement; (v) the rate of decrease in equipment surface temperature, the equipment including equipment selected from the group consisting of a heat exchanger, a separator or a distillation column; (vi) the rate of increase in furnace tube metal temperature; (vii) the rate of increase in the calculated fouling thermal resistivity of the heat exchanger and furnace; (viii) the rate of increase in heat exchanger pressure differential; (ix) the frequency of cleaning atmospheric and / or vacuum distillation columns; or (x) the frequency of maintenance turnarounds.

[0071] "Heavy oil" and "heavy oil feedstock" refer to heavy crude oil, oil sands bitumen, barrel bottoms, and residues left over from the oil refining process, such as visbreaker bottoms, and any other low-quality material that contains a large amount of high-boiling hydrocarbon fractions and / or contains a large amount of asphaltenes, which can deactivate heterogeneous catalysts and / or cause or contribute to the formation of coke precursors and deposits. Examples of heavy oils include, but are not limited to, Lloydminster heavy oil, Cold Lake bitumen, Athabasca bitumen, atmospheric tower bottoms, vacuum tower bottoms, residue (or "residual oil"), residual oil bitumen, vacuum residue oil (e.g., Ural VR, Arab Medium VR, Athabasca VR, Cold Lake VR, Maya VR, and Chichimene VR), pyrolysis oil, deasphalted liquid obtained by solvent deasphalting, asphaltene liquid obtained as a by-product of deasphalting, and non-volatile liquid fractions remaining after distillation, thermal separation, solvent extraction of crude oil, tar sands bitumen, liquefied coal, oil shale, or coal tar feedstocks, etc. As a further example, the atmospheric tower bottoms (ATB) may have a nominal boiling point of at least 343° C., although it will be appreciated that the cut point may vary between refineries and may be as high as 380° C. The vacuum tower bottoms may have a nominal boiling point of at least 524° C., although it will be appreciated that the cut point may vary between refineries and may be as high as 538° C. or even 565° C.

[0072] "High boiling hydrocarbon materials" and "high boiling hydrocarbons" refer to hydrocarbons having a nominal boiling point of at least about 524° C. in a processing facility. Examples include, but are not limited to, vacuum residue (produced from crude oil through a series of separation processes including vacuum distillation), vacuum bottoms (produced downstream from one or more hydroprocessing reactors after a series of separation processes including vacuum distillation), other heavy oil feedstocks, deasphalted heavy oils, and / or conditioned heavy oil feedstocks including catalyst precursors and / or dispersed catalysts.

[0073] "Mid-boiling hydrocarbon materials" and "mid-boiling hydrocarbons" refer to hydrocarbons in a process facility having a nominal boiling point in the range of about 200° C. to about 524° C. Examples include, but are not limited to, vacuum gas oils (which typically have a boiling range of 360-524° C.), atmospheric gas oils (which typically have a boiling range of 200-360° C.), decant or cycle oils (which typically have a boiling range of 360-550° C.), or other hydrocarbons having a nominal boiling point in the range of about 200 to 524° C.

[0074] "High boiling hydrocarbon diluent" refers to one or more high boiling hydrocarbons used as a diluent and mixed with the catalyst precursor to form a diluted precursor mixture. In addition to the one or more high boiling hydrocarbons, the high boiling hydrocarbon diluent may optionally include one or more medium boiling hydrocarbons.

[0075] "Catalyst precursor" refers to a compound, such as an oil-soluble compound, that contains or provides one or more catalyst metals, such as molybdenum. Exemplary catalyst precursors include organometallic complexes or compounds, more specifically oil-soluble compounds or complexes of transition metals and organic acids, which have a decomposition temperature or decomposition temperature range that is sufficiently high to avoid substantial decomposition when mixed with a heavy oil feedstock under suitable mixing conditions.

[0076] "Diluted precursor mixture" refers to a mixture of a hydrocarbon diluent and a catalyst precursor that is used to disperse the catalyst precursor into a heavy oil feedstock.

[0077] "Hydrocracking" and "hydroconversion" refer to processes where the primary purpose is to reduce the boiling range of heavy oils and where a large portion of the heavy oil is converted to products having a boiling range lower than the original feed. Hydrocracking or hydroconversion generally involves splitting larger hydrocarbon molecules into smaller molecular fragments having a smaller number of carbon atoms and a higher hydrogen-to-carbon ratio. The mechanism by which hydrocracking occurs generally involves the formation of hydrocarbon free radicals during thermal cracking, followed by the capping of the free radicals with hydrogen. The hydrogen atoms or free radicals that react with the hydrocarbon free radicals during the hydrocracking process may be generated at or from active catalyst sites.

[0078] "Hydrotreating" refers to a process whose primary purpose is to remove impurities such as sulfur, nitrogen, oxygen, halides and trace metals from the feedstock and to saturate olefins and / or stabilize hydrocarbon radicals by reacting them with hydrogen rather than reacting them with themselves. The primary purpose is not to change the boiling range of the feedstock. Hydrotreating is typically performed using a fixed bed reactor, but other hydroprocessing reactors such as ebullated bed hydrotreaters and slurry phase hydrotreaters may also be used.

[0079] "Hydrocracking" and "hydroconversion" may also include the removal of sulfur and nitrogen from the feedstock, as well as olefin saturation and other reactions typically associated with "hydrotreating." The terms "hydrotreating" and "hydroconversion" shall broadly refer to the "hydrocracking" and "hydrotreating" processes, which define both ends of the range and all processes in between along the range.

[0080] "Hydrocracking reactor" means any vessel in which the hydrocracking (i.e., lowering the boiling range) of a feedstock in the presence of hydrogen and a hydrocracking catalyst is the primary purpose. A hydrocracking reactor is characterized by having one or more inlets for introducing heavy oil and hydrogen therein, an outlet for removing upgraded feedstock or material therefrom, and sufficient thermal energy to promote the splitting of larger hydrocarbon molecules into smaller molecules, resulting in the formation of hydrocarbon free radicals. Examples of hydrocracking reactors include, but are not limited to, slurry phase reactors (i.e., two-phase gas-liquid systems), ebullating bed reactors (i.e., three-phase gas-liquid-solid systems), and fixed bed reactors (i.e., three-phase systems comprising a liquid feed trickling downward or flowing upward over a fixed bed of solid heterogeneous catalyst, with hydrogen typically flowing concurrently with the heavy oil, but countercurrent is also possible).

[0081] "Hydrocracking temperature" refers to the minimum temperature required to cause significant hydrocracking of the heavy oil feedstock. Generally, the hydrocracking temperature is preferably in the range of about 399°C (750°F) to about 460°C (860°F), more preferably in the range of about 418°C (785°F) to about 443°C (830°F), and most preferably in the range of about 421°C (790°F) to about 440°C (825°F).

[0082] "Gas-liquid slurry phase hydrocracking reactor" refers to a hydroprocessing reactor comprising a continuous liquid phase and a gaseous dispersed phase, which forms a "slurry" of gas bubbles in the liquid phase. The liquid phase typically comprises a hydrocarbon feedstock, which may contain a low concentration of dispersed metal sulfide catalyst particles, which may appear as a colloid or pseudosolute, and the gas phase typically comprises hydrogen, hydrogen sulfide, and vaporized low-boiling hydrocarbon products. The liquid phase may optionally include a hydrogen donor solvent.

[0083] When a solid catalyst is used with a liquid and a gas, a "gas-liquid-solid three-phase slurry hydrocracking reactor" is used. The gas may contain hydrogen, hydrogen sulfide, and vaporized low-boiling hydrocarbon products. The term "slurry phase reactor" broadly refers to two types of reactors (e.g., a reactor with dispersed metal sulfide catalyst particles, a reactor with micron-sized or larger particle catalysts, and reactors including both types).

[0084] "Solid heterogeneous catalyst," "heterogeneous catalyst," and "supported catalyst" refer to catalysts typically used in ebullating bed hydroprocessing systems and fixed bed hydroprocessing systems, including catalysts designed primarily for hydrocracking, hydroconversion, hydrodemetallization, and / or hydrotreating. Heterogeneous catalysts typically include a catalyst support structure having a large surface area and interconnecting channels or pores, and fine active catalyst particles, such as sulfides of cobalt, nickel, tungsten, and / or molybdenum, dispersed within the channels or pores. The pores of the support are typically of a limited size to maintain the mechanical integrity of the heterogeneous catalyst and to prevent decomposition and excessive formation of fines in the reactor. Heterogeneous catalysts can be prepared as cylindrical particles, cylindrical extrudates, other shapes, such as trilobes, rings, saddles, etc., or spherical solids.

[0085] "Dispersed metal sulfide catalyst particles" and "dispersed catalyst" refer to catalyst particles having a particle size of less than 1 μm (submicron or submicron), preferably less than about 500 nm, or less than about 250 nm, or less than or equal to about 100 nm, or less than or equal to about 50 nm, or less than about 25 nm, or less than about 10 nm, or less than 5 nm. The term "dispersed metal sulfide catalyst particles" may include molecules or molecularly dispersed catalyst compounds. "Dispersed metal sulfide catalyst particles" generally do not include metal sulfide particles greater than 1 μm and agglomerates of metal sulfide particles.

[0086] "Molecularly dispersed catalyst" refers to a catalyst compound that is substantially "dissolved" or dissociated from other catalyst compounds or molecules in a hydrocarbon feedstock or suitable diluent. It can include very small catalyst particles that contain a few catalyst molecules bound together (e.g., 15 molecules or less).

[0087] "Residual dispersed catalyst particles" and "residual dispersed metal sulfide catalyst particles" refer to catalyst particles that remain in the hydrocarbon product when transferred from one container to another (e.g., from a hydroprocessing reactor to a separator and / or other hydroprocessing reactors). Residual dispersed metal sulfide catalyst particles may also remain in the liquid residual fraction or asphalt after the hydrocarbon product is separated into a distillate and a residual liquid or asphalt, for example, by flash separation, thermal separation, atmospheric distillation, vacuum distillation, or vacuum stripping.

[0088] "Conditioned feedstock" means a hydrocarbon feedstock into which a catalyst precursor has been combined and thoroughly mixed so that when the catalyst precursor decomposes and forms an active catalyst, the catalyst will comprise dispersed metal sulfide catalyst particles formed in situ in the feedstock. Conditioned feedstocks include conditioned heavy oils.

[0089] "Upgrade," "upgrading," and "upgraded" when used to describe a feedstock or a resulting material or product that is or has been subjected to hydroprocessing, refers to one or more of a reduction in feedstock molecular weight, a reduction in the boiling range of the feedstock, a reduction in asphaltene concentration, a reduction in hydrocarbon radical concentration, and / or a reduction in the amount of impurities (e.g., sulfur, nitrogen, oxygen, halides, and metals).

[0090] "Severity" refers to the energy introduced into the heavy oil during the hydroprocessing process, which is related to the operating temperature of the hydroprocessing reactor (i.e., higher temperatures are associated with higher severity, while lower temperatures are associated with lower severity at the same or similar throughput) and the duration or residence time. An increase in severity generally increases the amount of conversion products produced by the hydroprocessing reactor, including both desired products and undesired products. Conversion rate and throughput also affect severity. For example, when temperature is increased and throughput remains unchanged, conversion rate will generally increase for a given feedstock. In order to maintain temperature while increasing throughput (i.e., increasing liquid hourly space velocity), which reduces the residence time of the heavy oil in the reactor, more thermal energy must be added to the system to offset the cooling effect of feeding a larger amount of initially cooler heavy oil to the reactor per unit time.

[0091] Desired conversion products include hydrocarbons with reduced molecular weight, reduced boiling point, and reduced specific gravity, which may include final products such as naphtha, diesel, jet fuel, kerosene, wax, fuel oil, etc. Other desired conversion products include high boiling hydrocarbons that can be further processed using conventional refining and / or distillation processes. A bottoms product of sufficient quality to be used as a fuel oil is another example of a desirable conversion product.

[0092] Undesirable conversion products include coke, sediments, metals and other solid materials (which can be deposited on hydroprocessing equipment and cause fouling, such as reactors, separators, filters, piping, towers, internal parts of heat exchangers) and heterogeneous catalysts. Low-quality conversion products can refer to the unconverted residual oil remaining after distillation, such as atmospheric tower bottoms ("ATB") or vacuum tower bottoms ("VTB"), especially residual oils that are too low in quality to be used as fuel oil or other desired uses. Minimizing unwanted conversion products reduces equipment fouling and the downtime required to clean the equipment.

[0093] In addition to temperature, "severity" can be related to one or both of "conversion" and "production volume". Whether the increase in severity involves an increase in conversion and / or an increase or decrease in production volume may depend on the quality of the heavy oil feedstock and / or the mass balance of the entire hydroprocessing system. For example, when it is desired to convert a larger amount of feed material and / or provide a larger amount of material to downstream equipment, the increased severity may mainly involve an increased production volume without necessarily increasing the conversion fraction. This can include situations where the residual oil fraction (ATB and / or VTB) is sold as fuel oil, and increasing the conversion rate without increasing production may reduce the amount of the product. In the case of wishing to increase the ratio of upgraded materials to the residual oil fraction, it may be desirable to mainly increase the conversion rate without necessarily increasing production volume. When the quality of the heavy oil introduced into the hydroprocessing reactor fluctuates, it may be necessary to selectively increase or decrease one or both of the conversion rate and production volume to maintain the desired ratio of upgraded materials to the residual oil fraction and / or the desired absolute amount of the final product being produced.

[0094] "Conversion" and "conversion fraction" refer to the proportion of heavy oil converted to lower boiling and / or low molecular weight materials, usually expressed as a percentage. Conversion is expressed as the percentage of the initial residual oil content (i.e., components with boiling points above the defined residual oil cut point) converted to products with boiling points below the defined cut point. The definition of the residual oil cut point can vary and can nominally include 524°C (975°F), 538°C (1000°F), 565°C (1050°F), etc. It can be measured by distillation analysis of the feed and product streams to determine the concentration of components with boiling points above the defined cut point. The conversion fraction is expressed as (FP) / F, where F is the amount of residual oil in the combined feed stream and P is the amount in the combined product stream, where both the feed and product residual oil contents are defined based on the same cut point. The amount of residual oil is usually defined based on the mass of components with boiling points above the defined cut point, but a volume or molar definition can also be used.

[0095] The conversion of asphaltenes may differ from the total conversion of heavy oil. For the purposes of this disclosure, a useful definition of asphaltene conversion is based on the relative amounts of asphaltenes in the fresh feedstock and the upgraded product and may be defined by the following formula, with the result being a decimal between 0 and 1, which may be converted to a percentage by multiplying by 100:

[0096] Conversion = [asphaltene (fresh feed) - asphaltene (product)] / asphaltene (fresh feed). The asphaltene content in the recycle stream is internal to the process. Recycle buildup of asphaltene can occur when the conversion of asphaltene is too low compared to the overall conversion of the heavy oil.

[0097] "Throughput" refers to the amount (mass or volume) of feed material introduced into a hydroprocessing reactor per unit time. Throughput can be expressed in terms of volume, such as barrels per hour or day, or in terms of mass, such as metric tons per hour or day. In common use, throughput is defined as the mass or volume feed rate of only the heavy oil feedstock itself (e.g., vacuum tower bottoms, etc.). This definition does not generally include the amount of diluent or other components that may be added to or included in the total feed to the hydroconversion unit, although definitions that include those other components may also be used.

[0098] "Space velocity" and "liquid hourly space velocity" are related to the throughput of a particular reactor or reactor size, but are normalized to remove the size (volume) of the reactor. Thus, a larger reactor can have twice the throughput, but the space velocity is the same as a reactor half the size. Thus, for a given reactor size, an increase in space velocity is generally proportional to an increase in throughput. Space velocity is inversely proportional to the residence time of the heavy oil in a reactor of a given reactor size.

[0099] The "production rate of conversion product" is an absolute rate, which may be expressed in terms of volume, such as barrels per hour or day, or in terms of mass, such as metric tons per hour or day. The "production rate of conversion product" should not be confused with yield or efficiency, which are sometimes incorrectly referred to as "rates" (e.g., production rate per unit feed rate, or production rate per unit of conversion feed). It should be understood that the actual values ​​of both the initial production rate of conversion product and the increased production rate of conversion product are specific to a single production facility and depend on the capacity of that facility. Therefore, it is valid to compare the production rates of related units or facilities before and after conversion, but not to compare different units or facilities with different capacities.

[0100] III. Example Hydroprocessing System

[0101] Figure 2-4B An example hydroprocessing reactor and system are shown that can be used in conjunction or integration with the disclosed methods and systems to mix a catalyst precursor into a heavy oil using a high boiling hydrocarbon diluent to form a conditioned heavy oil feedstock. The conditioned feedstock is heated to decompose the catalyst precursor, thereby forming dispersed metal sulfide catalyst particles in situ in the heavy oil feedstock. The heating can be performed upstream and / or within the hydroprocessing reactor.

[0102] The disclosed method and system can be used or placed anywhere in the hydroprocessing system shown. Generally, the method and system are generally used or positioned upstream of a hydroprocessing reactor configured to operate using a dispersed metal sulfide catalyst generated in situ in heavy oil. The disclosed method and system provide for continuously introducing a catalyst precursor into a heavy oil and forming dispersed metal sulfide catalyst particles in situ in the heavy oil, while being able to utilize a high boiling hydrocarbon as a diluent without prematurely decomposing the catalyst precursor.

[0103] The feedstocks that can be used in the disclosed hybrid methods and systems and hydroprocessed using one or more hydroprocessing reactors can include any desired fossil fuel feedstock and / or fractions thereof, including but not limited to one or more of heavy crude oil, oil sands bitumen, bottom of the barrel fractions from crude oil, atmospheric tower bottoms, vacuum tower bottoms, coal tar, liquefied coal, other residual oil fractions, pyrolysis oil, and deasphalted oil. Heavy oil and residual oil can include a significant proportion of high boiling hydrocarbons (i.e., nominal temperatures equal to or greater than 343°C (650°F), more specifically nominal temperatures equal to or greater than about 524°C (975°F) and / or asphaltenes. As described above and as Figure 1 As shown, asphaltenes are complex hydrocarbon molecules, including relatively low hydrogen-to-carbon ratios and a large number of fused aromatic and cycloalkane rings with paraffin side chains. The sheets composed of fused aromatic and cycloalkane rings are held together by heteroatoms such as sulfur or nitrogen, polymethylene bridges, thioether bonds and / or vanadium and nickel complexes. Asphaltenes also contain more sulfur and nitrogen than the rest of the crude oil or vacuum residue, and they also contain higher concentrations of carbon-forming compounds (i.e., compounds that form coke precursors and deposits).

[0104] Figure 2 An example ebullated bed hydroprocessing system 200 is schematically illustrated, which utilizes a dual catalyst system of dispersed metal sulfide catalyst particles and a heterogeneous ebullated bed catalyst. The ebullated bed hydroprocessing system 200 includes an ebullated bed reactor 230 and a separator 204 (e.g., a hot separator, an interstage pressure difference separator, or a distillation column). The ebullated bed reactor 230 is similar to the reactor used in the LC-refining hydrocracking system developed by CE Lummus. Catalyst precursor 202 is mixed with hydrocarbon diluent 203 in one or more premixers 206 to form a diluted precursor mixture 209. The diluted precursor mixture 209 is added to the heavy oil feedstock 208 and mixed therewith using a mixing system 210 to form a conditioned feedstock 211.

[0105] The conditioned feedstock 211 is fed into a buffer tank 212 having a pump circulation loop 214 to achieve further mixing and dispersion of the catalyst precursor 202 in the feedstock 208. A bypass line (not shown) returns any heavy oil that bypasses the mixing line (not shown) to a common discharge line (not shown) and / or feeds the heavy oil directly into the buffer tank 212. The buffer tank 212 and the pump circulation loop 214 advantageously further mix the catalyst precursor into the heavy oil (including the heavy oil from the bypass line). The conditioned feedstock from the buffer tank 212 is pressurized by one or more pumps 216, passes through a preheater 218, and is fed into the ebullated bed hydroprocessing reactor 230 together with hydrogen 220 through one or more inlets 236, which are located at or near the bottom of the ebullated bed reactor 230.

[0106] The ebullated bed reactor 230 includes a hydrocarbon material 226 and an expanded catalyst zone 242, the expanded catalyst zone 242 including a heterogeneous catalyst 244 typically used in an ebullated bed reactor, which is maintained in an expanded or fluidized state against gravity by the upward movement of liquid hydrocarbons 226 and gas. A lower heterogeneous catalyst-free zone 248 is located below a distributor grid defining the bottom of the expanded catalyst zone 242, and an upper heterogeneous catalyst-free zone 250 is located above the expanded catalyst zone 242. Dispersed metal sulfide catalyst particles 224 are dispersed throughout the hydrocarbon material 226 within the ebullated bed reactor 230, including in the expanded catalyst zone 242 and the heterogeneous catalyst-free zones 248, 250, and can be used to promote beneficial upgrading reactions in the absence of a heterogeneous catalyst 244.

[0107] The funnel-shaped recycle cup 256 fed into the recycle channel 252 connected to the ebullating pump 254 continuously recycles the hydrocarbon material 226 from the upper heterogeneous catalyst-free zone 250 to the lower heterogeneous catalyst-free zone 248. The downward suction of the recycle cup 256 at the top of the recycle channel 252 draws the hydrocarbon material 226 containing the dispersed catalyst particles 224 from the upper heterogeneous catalyst-free zone 250 downward through the recycle channel 252 and into the bottom of the ebullating bed reactor 230 via the ebullating pump 254. The recycled hydrocarbon material 226 is mixed with a new feed containing dispersed metal sulfide catalyst particles (and / or catalyst precursor) and hydrogen 220.

[0108] Fresh heterogeneous catalyst 244 may be periodically introduced into the ebullating bed reactor 230 via catalyst inlet conduit 258, and spent heterogeneous catalyst 244 may be periodically removed via catalyst removal conduit 260. Dispersed metal sulfide catalyst particles 224 provide additional catalytic activity within the expanded catalyst zone 242, recycle passage 252, and lower and upper heterogeneous catalyst-free zones 248, 250. The catalytic addition of hydrogen to the hydrocarbons external to the heterogeneous catalyst 244 reduces or minimizes the formation of deposits and coke precursors, which are often responsible for deactivation of the heterogeneous catalyst and lead to fouling of the system.

[0109] The ebullating bed reactor 230 also includes an outlet 238 located at or near the top, through which the converted material 240 is discharged. The converted material 240 is introduced into the separator 204, and the separator 204 separates the volatile fraction 205 from the residual oil fraction 207. The volatile fraction 205 is taken out from the top of the hot separator 204, and the residual oil fraction 207 is taken out from the bottom of the hot separator 204. The resid fraction 207 contains residual dispersed metal sulfide catalyst particles, schematically represented as catalyst particles 224". If desired, at least a portion of the resid fraction 207 can be recycled back to the ebullated bed reactor 230 to form a portion of the feed material and provide additional dispersed metal sulfide catalyst particles. Alternatively, the resid fraction 207 can be further processed using downstream processing equipment (e.g., another ebullated bed reactor, a distillation column, a deasphalting unit, etc.). A portion of the resid fraction 207 can be used as part or all of the hydrocarbon oil diluent 203 added to the premixer 206 to form a diluted catalyst precursor 209.

[0110] Figure 3A Another type of ebullated bed hydroprocessing reactor 310 is schematically illustrated, having a different recycle system typical of the H-Oil hydrocracking system developed by Hydrocarbon Research, Inc. and currently licensed by Axens. The ebullated bed reactor 310 includes an inlet 312 through which a heavy oil feedstock 314 and pressurized hydrogen 316 are introduced, and an outlet 318 through which upgraded hydrocarbon material 320 is withdrawn.

[0111] An expanded catalyst zone 322 containing a heterogeneous catalyst 324 is bounded by a distributor grid plate 326 and an upper end 329, the distributor grid plate 326 separating the expanded catalyst zone 322 from a lower catalyst-free zone 328 below the distributor grid plate 326, and the upper end 329 defining an approximate boundary between the expanded catalyst zone 322 and the upper catalyst-free zone 330. A dashed boundary line 331 schematically illustrates an approximate level when the heterogeneous catalyst 324 is not in an expanded or fluidized state. Dispersed metal sulfide catalyst particles 325 are dispersed throughout the hydrocarbon mass in the ebullating bed reactor 310, both in the expanded catalyst zone 322 and in the lower and upper heterogeneous catalyst free zones 228, 230.

[0112] The hydrocarbons and other materials in the ebullating bed reactor 310 are continuously recirculated through a recirculation channel 332 connected to an ebullating pump 334 located outside the reactor 310. The materials are withdrawn from the upper heterogeneous catalyst-free zone 330 through a funnel-shaped recirculation cup 336. The recirculation cup 336 helps to separate hydrogen bubbles from the recirculated materials passing downward through the recirculation channel 332 to prevent cavitation in the ebullating pump 334. The recirculated materials enter the lower heterogeneous catalyst-free zone 328 through the discharge bell cover 343, where it is mixed with fresh heavy oil feedstock 314 and hydrogen 316. The mixture passes upward through the distributor grid 326 and enters the expanded catalyst zone 322. Fresh heterogeneous catalyst can be periodically introduced into the expanded catalyst zone 322 through the catalyst inlet pipe 336, and the used heterogeneous catalyst can be periodically withdrawn through the catalyst discharge pipe 340.

[0113] Figure 3A The H-Oil fluidized bed reactor 310 and Figure 2 The main difference between the LC Fining ebullated bed reactors 200 shown is the location of the ebullated pump. The ebullated pump 334 in the H-Oil reactor 310 is located outside the reaction chamber. The recirculated material is introduced through a recirculation port with a distributor cap 343 at the bottom of the ebullated bed reactor 310. The distributor cap 343 helps to evenly distribute the material through the lower catalyst-free zone 328.

[0114] The upgraded material 320 is taken out from the outlet 318 of the ebullated bed reactor 310 and introduced into a separator 342 (e.g., a hot separator, an interstage pressure difference separator, an atmospheric distillation column, or a vacuum distillation column). The separator 342 is configured to separate a volatile fraction (gas and distillate) 346 from a non-volatile fraction (or liquid) 348. The distillate and gas 346 are removed at one position (e.g., the top) of the separator 342, and a non-volatile fraction 348 containing liquid hydrocarbons and residual dispersed metal sulfide catalyst particles is removed from another position (e.g., the bottom) of the separator 342.

[0115] Figure 3B A hydroprocessing system 300 is schematically depicted, which includes a slurry phase reactor 302 and a separator 304 (e.g., a hot separator, an interstage pressure differential separator, or a distillation column). A heavy oil feedstock 306 is mixed and conditioned with a catalyst precursor mixture 308 using a mixing system 310. The diluted precursor mixture 308 includes a catalyst mixed with a diluent formed in a premixer (not shown). The conditioned feedstock from the mixing system 310 is pressurized by a pump 312, which can also be used as a multi-stage mixing device to further disperse the catalyst precursor throughout the heavy feedstock 306, passes through a preheater 314, and is fed into the slurry phase reactor 302 along with hydrogen 316 through one or more input ports 318 located at or near the bottom of the slurry phase reactor 302.

[0116] The agitator 320 at the bottom of the slurry phase reactor 302 induces mixing in the liquid phase, thereby helping to more evenly disperse the heat generated by the hydrocracking reaction. Alternatively, or in addition to the agitator 320, the slurry phase reactor 302 may include a circulation channel, a circulation pump, and a distributor grid (not shown), as in a conventional ebullating bed reactor (see Figure 2 and 3A ) to promote a more uniform dispersion of reactants, catalysts, and heat. Hydrogen is schematically depicted as bubbles 322, and dispersed metal sulfide catalyst particles are schematically depicted as catalyst particles 324 in reactor 302. It should be understood that bubbles 322 and catalyst particles 324 are shown enlarged so that they can be seen in the figure. In fact, they may not be visible to the naked eye.

[0117] The heavy oil feedstock 306 is catalytically upgraded in the presence of hydrogen 316 and a dispersed metal sulfide catalyst 324 in the slurry phase reactor 302 to form an upgraded hydrocarbon product 326. The upgraded product 326 is continuously withdrawn from the slurry phase reactor 302 through an output port 328 located at or near the top of the reactor 302 and then fed to a separator 304 (e.g., a hot separator and / or a distillation column), optionally after passing through an optional hydroprocessing unit 330. The upgraded product 326 fed to the separator 304 contains residual catalyst particles, schematically depicted as particles 324', and residual hydrogen, schematically depicted as bubbles 322', which can continue to promote beneficial upgrading reactions and reduce equipment fouling. The separator 304 separates the volatile fraction 305 from the non-volatile fraction 307. The volatile fraction 305 is taken out from the top of the hot separator 304 , and the non-volatile fraction 307 is taken out from the bottom of the hot separator 304 .

[0118] Figure 3CA hydroprocessing system 300 is schematically depicted, which includes a slurry phase reactor 302, a hot separator 304, and a fixed bed reactor 360. The upgraded hydrocarbon material 326 contains residual dispersed metal sulfide catalyst particles, schematically depicted as particles 324' in the hot separator 304. The residual dispersed metal sulfide catalyst particles 324' in the liquid fraction 307 from the hot separator 304 are introduced into the fixed bed reactor 360 for further hydroprocessing. The fixed bed reactor 360 can be designed to perform hydrocracking and / or hydroprocessing reactions depending on the operating temperature and / or the type of solid supported catalyst used in the fixed bed reactor 360.

[0119] The fixed bed reactor 360 more specifically includes an input port 362 at the top (through which the liquid fraction 307 and supplemental hydrogen 364 are introduced), and an output port 366 at the bottom (through which further hydroprocessed material 388 is discharged). The fixed bed reactor 360 also includes a plurality of vertically stacked and spaced catalyst beds 370, which include a filled porous supported catalyst. Above each catalyst bed 370 is a distributor grid 372, which helps to more evenly distribute the feedstock flow passing downward through the catalyst bed 370. An unloaded catalyst zone 374 exists above and below each catalyst bed 370. In both the catalyst bed 370 and the unloaded catalyst zone 374, the residual catalyst particles 324' remain dispersed throughout the feedstock within the fixed bed reactor 360, which further promotes beneficial quality improvement reactions. An auxiliary port 376 may be provided at the center and / or bottom of the fixed bed reactor 360, through which cooling oil and / or hydrogen quenching may be introduced to cool the heat generated by the hydroprocessing reaction and control the reaction rate, thereby helping to prevent the formation of coke precursors and deposits and / or excess gas within the fixed bed reactor 360.

[0120] Figure 4A Schematically illustrated is an ebullated bed hydroprocessing system 400 including a plurality of ebullated bed reactors 410. The hydroprocessing system 400 (an example of which is a LC-refining or H-Oil hydroprocessing unit) can include three ebullated bed reactors 410a, 410b, 410c in series for upgrading a feedstock 412. The feedstock 412 from a buffer tank 414 is pressurized, preheated, and introduced into a first ebullated bed reactor 410a together with hydrogen 416, and the feedstock 412 and hydrogen 416 are passed through respective heaters before entering the first reactor 410a. The upgraded hydrocarbon material 420a from the first ebullated bed reactor 410a is introduced into a second ebullated bed reactor 410b together with additional hydrogen 416. The upgraded hydrocarbon material 420b from the second ebullated bed reactor 410b is introduced into a third ebullated bed reactor 410c together with additional hydrogen 416.

[0121] It should be understood that one or more interstage separators (not shown) may be optionally inserted between the first and second ebullated bed reactors 410a, 410b and / or between the second and third ebullated bed reactors 410b, 410c to remove low boiling fractions and gases from the non-volatile fraction containing liquid hydrocarbons and residual dispersed metal sulfide catalyst particles. It may be desirable to remove lower alkanes, such as hexane and heptane, which are valuable fuel products but are poor solvents for asphaltenes. Removing volatile substances between multiple reactors increases the yield of upgraded products and increases the solubility of asphaltenes in liquid hydrocarbon materials fed to downstream reactors. Both improve the efficiency of the entire hydroprocessing system.

[0122] The upgraded hydrocarbon material 420c from the third ebullated bed reactor 410c is sent to a high temperature separator 442a, which separates volatile and non-volatile fractions. The volatile fraction 446a passes through a heat exchanger 450 (the heat removed by the heat exchanger 450 can be used to preheat the hydrogen 416) and is then fed to the first ebullated bed reactor 410a. The slightly cooled volatile fraction 446a is sent to a medium temperature separator 442b, which separates the remaining volatile fraction 446b from the resulting liquid fraction 448b formed by cooling the heat exchanger 450. The remaining volatile fraction 446b is sent to a downstream low temperature separator 442c for further separation into a gas fraction 452c and a degassed liquid fraction 448c.

[0123] The liquid fraction 448a from the high temperature separator 442a is combined with the obtained liquid fraction 448b from the medium temperature separator 442b, and the mixture is sent to the low pressure separator 442d, which separates the degassed liquid fraction 448d from the hydrogen-rich gas 452d. The degassed liquid fraction 448d is sent together with the degassed liquid fraction 448c from the low temperature separator 442c to the back-end system 460, and the back-end system 460 includes one or more distillation columns, including a vacuum distillation column, in which the substances are fractionated into products.

[0124] The gaseous fraction 452c from the low temperature separator 442c is purified into waste gas, purge gas and hydrogen 416. The hydrogen 416 is compressed, mixed with supplementary hydrogen 416a, and either passed through a heat exchanger 450 and introduced into the first ebullated bed reactor 410a together with the feedstock 412, or directly introduced into the second and third ebullated bed reactors 410b, 410c.

[0125] Figure 4B The ebullated bed hydroprocessing system 400 is schematically illustrated and includes a plurality of ebullated bed reactors, which is similar to Figure 4AThe system shown in the figure, but shows an interstage separator 421 between the second and third ebullated bed reactors 410b, 410c (although the interstage separator 421 (or other separator) can be between the first and second ebullated bed reactors 410a, 410b). As shown, the effluent from the second stage ebullated bed reactor 410b enters the interstage separator 421, which can be a high pressure, high temperature separator. The liquid fraction from the separator 421 is combined with a portion of the recycled hydrogen from the pipeline 416 and fed into the third stage reactor 410c. The vapor fraction from the interstage separator 421 bypasses the third stage reactor 410c, mixes with the effluent from the third stage reactor 410c, and then enters the high pressure and high temperature separator 442a.

[0126] This allows the lighter, more saturated components formed in the first two reactors 410a, 410b to bypass the third reactor 410c. This has the benefits of (1) reducing the vapor load on the third reactor 410c, which increases the volume utilization of the third reactor for converting the remaining heavy components, and (2) reducing the concentration of "anti-solvent" components (saturates) that can destabilize (e.g., precipitate) the asphaltenes in the third reactor 410c.

[0127] Hydroprocessing systems are typically configured and operated to promote more vigorous hydrocracking reactions rather than less vigorous hydrotreating reactions such as hydrotreating. Hydrocracking involves the breaking of carbon-carbon molecular bonds, such as reducing the molecular weight of larger hydrocarbon molecules and / or the opening of aromatic rings. Hydrotreating, on the other hand, primarily involves the hydrogenation of unsaturated hydrocarbons with little or no breaking of carbon-carbon molecular bonds.

[0128] In order to promote more vigorous hydrocracking reactions rather than less vigorous hydrotreating reactions, the hydrotreating reactor is preferably operated at a temperature in the range of about 750°F (399°C) to about 860°F (460°C), more preferably in the range of about 780°F (416°C) to about 830°F (443°C), preferably at a pressure in the range of about 1000 psig (6.9 MPa) to about 3000 psig (20.7 MPa), more preferably in the range of about 1500 psig (10.3 MPa) to about 2500 psig (17.2 MPa), and preferably at a rate of about 0.05 hr. -1 To about 0.45hr -1 , more preferably about 0.1 hr -1 To about 0.35hr -1 The difference between hydrocracking and hydrotreating can be expressed in terms of resid conversion (hydrocracking results in a large conversion of higher boiling hydrocarbons to lower boiling hydrocarbons, while hydrotreating does not).

[0129] The hydroprocessing system disclosed herein can result in a total resid conversion in the range of about 60% to about 95%, preferably in the range of about 75% to about 90%. Due to the differences in processing difficulty between different feedstocks, the preferred conversion range generally depends on the type of feedstock.

[0130] Compared to operating an ebullated bed reactor with a heterogeneous catalyst alone, operating an ebullated bed reactor with a dual catalyst system can result in the same or reduced equipment fouling. For example, when a dual catalyst system is used instead of a heterogeneous catalyst alone, the rate of equipment fouling can result in one or more of the following benefits: (i) reducing the frequency of heat exchanger shutdowns and / or distillation column shutdowns for cleaning; (ii) reducing the frequency of filter and strainer replacement or cleaning; (iii) reducing the frequency of switching to a backup heat exchanger; (iv) reducing the surface temperature of equipment such as a heat exchanger, separator, or distillation column; (v) reducing the rate of increase in furnace tube metal temperature; and (vi) reducing the rate of increase in the calculated fouling thermal resistance coefficient of a heat exchanger.

[0131] IV. Method and system for mixing catalyst precursor into heavy oil using high boiling point hydrocarbon diluent

[0132] Figure 5 An example mixing system and corresponding method for producing a conditioned heavy oil feedstock using one or more high boiling point hydrocarbons as a diluent to form a diluted precursor mixture is illustrated. Figure 6 An example method for producing a well-mixed conditioned heavy oil feedstock using one or more high boiling point hydrocarbons as a diluent to form a diluted precursor mixture is illustrated. Figures 7A-8B An exemplary mixing system for mixing a catalyst precursor into a heavy oil feedstock using a diluted precursor mixture formed of the catalyst precursor and a high boiling point hydrocarbon diluent is illustrated.

[0133] Figure 5 An exemplary mixing system 500 and its underlying method for mixing a catalyst precursor 504 into a heavy oil feedstock 502 using a high boiling hydrocarbon diluent 506 to form a conditioned heavy oil feedstock 514 is schematically illustrated. The high boiling hydrocarbon diluent 506 is initially mixed with the catalyst precursor 504 using a premixer 508 to form a diluted precursor mixture 510. A medium boiling hydrocarbon diluent 520 may optionally be added to the premixer 508 and / or the cooler 516 to form a mixed high boiling hydrocarbon diluent, which is then mixed with the heavy oil feedstock 502 via a main mixing system 512 to form the conditioned feedstock 514, the high boiling hydrocarbon diluent being used to prepare the diluted precursor mixture 510. The main mixing system 512 may include one or more static inline mixers and / or one or more high shear mixers.

[0134] The high boiling hydrocarbon diluent 506 includes at least one high boiling hydrocarbon material having a nominal boiling point of at least 524°C, which has been cooled using a cooler 516 before mixing with the catalyst precursor 504. The cooler may include one or more heat exchangers or other cooling devices known in the art. In some embodiments, the high boiling hydrocarbon diluent 506 comprises a portion of the heavy oil feedstock 502. To achieve this, a pipeline provides a side stream of the heavy oil feedstock 502 to the cooler 516. In other embodiments, the high boiling hydrocarbon diluent 506 comprises a portion of the conditioned heavy oil feedstock 514. To achieve this, a pipeline provides a side stream of the conditioned heavy oil feedstock 514 to the cooler 516. In other embodiments, the high boiling hydrocarbon diluent 506 comprises a vacuum tower bottoms 518, such as from a column used to separate heavy oil from a hydroprocessing system (e.g., from Figure 2-4B In other embodiments, the high boiling hydrocarbon diluent comprises deasphalted oil (not shown) or other high boiling hydrocarbons or heavy oils from the process (not shown).

[0135] The medium boiling hydrocarbon diluent 520 (which optionally may be used with or form part of the high boiling hydrocarbon diluent 506 to form a diluted precursor mixture 510 with the catalyst precursor 504) may include one or more medium boiling hydrocarbons having a nominal boiling point in the range of about 200° C. to about 524° C. Non-limiting examples include vacuum gas oils, atmospheric gas oils, and cycle oils.

[0136] The main mixing system 512 for mixing the diluted precursor mixture 510 with the heavy oil feedstock 502 may include any mixer or combination of mixers capable of mixing the diluted precursor mixture 510 into the heavy oil feedstock 502. Examples include Figures 7A-8B Examples of mixers that may be included in the main mixing system 512 include, but are not limited to, one or more static inline mixers, one or more high shear mixers, a surge tank, and / or one or more high pressure pumps for introducing the conditioned feedstock 514 into a hydroprocessing reactor (not shown).

[0137] Figure 6 is a flow chart illustrating an example method of forming a well-mixed and conditioned feedstock comprising a catalyst precursor well-mixed, such as substantially uniformly mixed, with a heavy oil feedstock. The well-mixed conditioned feedstock may be heated to form dispersed metal sulfide catalyst particles in situ in the heavy oil feedstock.

[0138] The first step includes providing a high boiling hydrocarbon diluent to be mixed with the catalyst precursor to form a diluted precursor mixture. The high boiling hydrocarbon diluent may include one or more high boiling hydrocarbon materials, such as a portion of a heavy oil feedstock, a portion of a conditioned feedstock, a vacuum bottoms from a crude oil distillation or hydroprocessing system, deasphalted oil, or one or more other hydrocarbon materials having a nominal boiling point of at least about 350°C, preferably at least about 400°C, more preferably at least about 450°C, most preferably at least about 500°C, such as at least about 524°C.

[0139] In some embodiments, the temperature of the high boiling hydrocarbon diluent will be too high to mix with the catalyst precursor, for example, because it will cause premature thermal decomposition and agglomeration of the precursor before the precursor is fully mixed with the high boiling hydrocarbon diluent to form a diluted precursor mixture. For example, the heavy oil feedstock can be maintained at a temperature in the range of about 125°C to about 200°C, depending on its viscosity properties. The conditioned feedstock (after addition and mixing of the dispersed catalyst) can be at an even higher temperature of about 160°C to about 300°C. The vacuum bottoms of the hydroconversion process or unit can also be at a higher temperature of about 150°C to about 300°C.

[0140] In this case, the method includes a step of cooling the high boiling hydrocarbon diluent to a temperature below the decomposition temperature of the catalyst precursor. This can be achieved using a cooler known in the art, such as one or more heat exchangers. Depending on the high boiling hydrocarbon diluent used, care should be taken to sufficiently cool the high boiling hydrocarbon diluent to prevent significant thermal decomposition of the catalyst precursor when mixed with it, while ensuring that the temperature remains high enough to allow the high boiling hydrocarbon diluent to flow through the mixing device and conduit. In order to solve this problem, the present invention provides a cooler for controlling the temperature of the high boiling hydrocarbon diluent. The selection and control of this temperature is critical because it must be high enough to allow the high boiling hydrocarbon material to have a low enough viscosity to make it flowable and mixable, but low enough to avoid undesirable agglomeration of the catalyst precursor. In view of the above, the high boiling diluent can be cooled to a temperature in the range of about 75°C to about 150°C. Preferably, the temperature can be cooled to a temperature in the range of about 75°C to about 125°C. More preferably, the temperature can be cooled to a temperature in the range of about 75°C to about 95°C.

[0141] In some embodiments, at least a portion of the cooling can be provided by optionally mixing a high boiling hydrocarbon diluent with a medium boiling hydrocarbon diluent that is already at a temperature below the decomposition temperature of the catalyst precursor. The extent of any such cooling will depend on the temperature of the high boiling hydrocarbon diluent, the temperature of the medium boiling hydrocarbon diluent, the relative amounts of the high boiling hydrocarbon diluent and the medium boiling hydrocarbon diluent, and the target temperature of the combined diluents.

[0142] When the temperature of the high boiling hydrocarbon diluent has been appropriately adjusted to be compatible with the catalyst precursor, the method includes the step of mixing the catalyst precursor with the cooled high boiling hydrocarbon diluent to produce a diluted precursor mixture. This can be achieved using one or more mixers known in the art and / or disclosed herein. The catalyst precursor is advantageously mixed with the hydrocarbon diluent at a temperature below the temperature at which most of the catalyst precursor decomposes. The mixing can be carried out in the range of about 40°C (104°F) to about 250°C (482°F), or in the range of about 60°C (140°F) to about 200°C (392°F), or in the range of about 75°C (167°F) to about 125°C (257°F). The temperature at which the diluted precursor mixture is formed may depend on the decomposition temperature and / or other properties of the catalyst precursor used and / or the properties of the hydrocarbon diluent, such as viscosity.

[0143] The duration of mixing may be in the range of about 0.1 seconds to about 5 minutes, or in the range of about 0.5 seconds to about 1 minute, or in the range of about 1 second to about 10 seconds.

[0144] The ratio of catalyst precursor to hydrocarbon diluent is preferably in the range of about 1:1000 to about 1:1 by weight, more preferably in the range of about 1:500 to about 1:10, and most preferably in the range of about 1:300 to about 1:50 (e.g., 1:600, 1:400, 1:300, 1:200, 1:100, or 1:60). The amount of catalyst metal (e.g., platinum) in the diluted precursor mixture is preferably in the range of about 100 ppm to about 7000 ppm, more preferably in the range of about 300 ppm to about 4000 ppm (e.g., 250 ppm, 500 ppm, 750 ppm, or 2500 ppm by weight) based on the weight of the diluted precursor mixture.

[0145] The diluted precursor mixture is then mixed with the heavy oil feedstock using one or more mixers to form a conditioned heavy oil feedstock. The mixer used in this step can be any mixer or combination of mixers capable of mixing the diluted precursor mixture into the heavy oil feedstock, such as one or more static inline mixers, one or more high shear mixers, a surge tank, and / or one or more high pressure pumps for introducing the conditioned feedstock into the hydroprocessing reactor.

[0146] The step of mixing the diluted precursor mixture with the heavy oil feedstock may be in the range of about 0.1 seconds to about 5 minutes, or in the range of about 0.5 seconds to about 3 minutes, or in the range of about 1 second to about 1 minute.

[0147] The heavy oil feedstock and the diluted precursor mixture are advantageously mixed at a temperature in the range of about 40°C (104°F) to about 350°C (662°F), or in the range of about 60°C (140°F) to about 300°C (572°F), or in the range of about 75°C (167°F) to about 250°C (482°F) to produce a conditioned feedstock.

[0148] Because the catalyst precursor is premixed with a hydrocarbon diluent to form a diluted precursor mixture, which is then mixed with the heavy oil feedstock, the feedstock can be at or above the decomposition temperature of the catalyst precursor. In some cases, the hydrocarbon diluent protects individual catalyst precursor molecules, prevents them from aggregating to form larger particles, temporarily isolates the catalyst precursor molecules from heat from the heavy oil during mixing, and promotes the catalyst precursor molecules to disperse quickly enough throughout the feedstock before decomposing to release metals. In addition, additional heating of the feedstock may be required to release hydrogen sulfide from sulfur-containing molecules in the heavy oil to form metal sulfide catalyst particles. In this way, the gradual dilution of the catalyst precursor allows for high dispersion in the heavy oil, thereby forming highly dispersed metal sulfide catalyst particles, even if the feedstock is at a temperature above the decomposition temperature of the catalyst precursor.

[0149] The high boiling hydrocarbon diluent may be used in an amount ranging from 0.1% to 10% by volume, or from about 0.5% to about 5% by volume of the total feedstock entering the hydroprocessing unit. The sources of high boiling diluents (e.g., heavy oil feedstock, conditioned heavy oil feedstock, vacuum residue, deasphalted heavy oil, and vacuum bottoms) may be used alone at 0.1% to 10%, or from about 0.5% to about 5% of the total heavy oil feedstock, or they may be used in any combination of 0% to 10%, or from about 0.5% to about 5% of the total heavy oil feedstock. Such a source of high boiling hydrocarbon diluents may optionally be combined with one or more medium boiling hydrocarbons alone, or with one or more sources of heavy boiling diluents in any combination, with a total amount of 0.5% to 5% of the total heavy oil feedstock.

[0150] In some embodiments, the conditioned feedstock is preheated using one or more heaters known in the art. This raises the temperature above the decomposition temperature of the catalyst precursor, thereby releasing the catalyst metal, which can react with sulfur present in and / or added to the heavy oil feedstock (e.g., as hydrogen sulfide gas) to form active dispersed metal sulfide catalyst particles in situ in the heavy oil.

[0151] Fig. 7AAn exemplary system 700 for mixing a catalyst precursor 702 into a heavy oil feedstock 708 to form a conditioned feedstock is schematically illustrated. The catalyst precursor 702 is first mixed with a hydrocarbon oil diluent 704 by a first static inline low shear mixer 706 to advantageously form a diluted precursor mixture. The catalyst precursor 702 is preferably oil soluble. The hydrocarbon oil diluent 704 includes one or more high boiling hydrocarbon materials and optionally one or more medium boiling materials.

[0152] The catalyst precursor composition 702 is advantageously mixed with the hydrocarbon oil diluent 704 at a temperature at which a substantial portion of the catalyst precursor composition 702 begins to decompose. It should be appreciated that the actual temperature at which the diluted precursor mixture is formed will generally depend greatly on the decomposition temperature of the particular precursor composition used. When the hydrocarbon oil diluent 704 is initially too hot, e.g., hotter than the decomposition temperature of the catalyst precursor 702, it first passes through a cooler 705 to reduce its temperature, e.g., to below the decomposition temperature of the catalyst precursor 702.

[0153] The initial degree of mixing achieved in the inline mixer 706 depends at least in part on the number of stages in the low shear static inline mixer. In one embodiment, the mixer 706 is characterized by including about 2 to about 20 stages, preferably about 7 to about 15 stages, and more preferably about 8 to about 12 stages. In mixing theory, each "stage" is essentially equivalent to a container with a violent stir. Since mixing is imperfect (i.e., the components to be mixed will short-circuit the container), if a series of mixing containers (i.e., multi-stage containers) are used, the degree of mixing will be improved. The exemplary static inline mixer 706 does not include moving parts, but includes multiple internal baffles or other elements in a tube or other housing. The internal baffles or other elements are repeatedly divided and re-combined in a turbulent manner to guide the flowing fluid to different directions, thereby mixing various components. When compared with the degree of mixing that occurs when using a series of mixing containers (i.e., the fluid leaving the first container enters the second container for mixing, the fluid leaving the second container enters the third container, etc.), the number of stages in the static inline mixer is empirically related to the expected degree of mixing in the static mixer. In other words, the static inline mixer may be characterized as comprising 10 stages which provide a degree of mixing substantially equivalent to that provided by a mixing system consisting of a series of 10 mixing vessels.

[0154] Diluting the catalyst precursor with a hydrocarbon diluent prior to mixing with the heavy oil feedstock helps achieve thorough mixing of the precursor in the heavy oil feedstock because the hydrocarbon oil diluent is more miscible with the heavy oil feedstock than the catalyst precursor itself. It is important to premix the catalyst precursor with the hydrocarbon diluent and to take care throughout the process and mixing system to mix the components for a sufficient period of time to thoroughly mix the precursor with the feedstock before substantial decomposition of the precursor occurs.

[0155] Advantageously, it has been found that premixing the precursor composition 702 with the hydrocarbon diluent 704 prior to mixing the diluted precursor mixture with the heavy oil feedstock 708 greatly aids in thoroughly and intimately mixing the precursor composition 702 into the feedstock 708. Forming a diluted precursor mixture advantageously reduces the overall mixing time by: (1) reducing or eliminating solubility differences between the more polar catalyst precursor 702 and the heavy oil feedstock 708, (2) reducing or eliminating viscosity differences between the catalyst precursor composition 702 and the heavy oil feedstock 708, and / or (3) disrupting bonds or associations between catalyst precursor molecular clusters, forming solutes in the hydrocarbon diluent 704 that are more easily dispersed in the heavy oil feedstock 708.

[0156] When the heavy oil feedstock 708 contains water (e.g., condensed water), it is particularly advantageous to first form a diluted precursor mixture. Otherwise, the greater affinity of water for the polar catalyst precursor 702 can cause localized aggregation of the precursor, resulting in poor dispersion and the formation of micron-sized or larger catalyst particles. The hydrocarbon diluent 704 is preferably substantially free of water (i.e., contains less than about 0.5% water) to prevent the formation of a large number of micron-sized or larger catalyst particles.

[0157] The diluted precursor mixture is then combined with the heavy oil feedstock 708 and mixed for a sufficient time to disperse the catalyst precursor throughout the feedstock and produce a conditioned feedstock in which the precursor is thoroughly mixed in the heavy oil feedstock. In the illustrated mixing system 700, the heavy oil feedstock 708 and the diluted precursor mixture are mixed in a second low shear static inline mixer 710. Similar to the first mixer 706, the second mixer 710 preferably includes 2 to 20 stages, more preferably 7 to 15 stages, and most preferably 8 to 12 stages.

[0158] The second static inline mixer 710 is followed by a dynamic high shear mixer 712 (e.g., a container with a propeller or turbine impeller for providing very turbulent high shear mixing). An example of a suitable dynamic high shear mixer is an 800LS inline mixer, manufactured by Silverson Machines, Ltd., located in Waterside, England. The mixing time in the static inline mixer depends on the number of stages and the volume flow rate of each component. Increasing the intensity and / or shear energy of the mixing process in the high shear mixer 712 can reduce the mixing time required to achieve thorough mixing of the catalyst precursor 702 in the heavy oil feedstock 708. The mixing time in the static inline mixer 710 can advantageously include a large portion of the total mixing time. This configuration uses the pressure drop of the static mixer 710 to advantageously achieve a certain degree of mixing, followed by or before additional mixing in the high shear mixer 712.

[0159] Additional equipment may be included downstream within the system 700 to provide additional mixing of the catalyst precursor to achieve a high degree of dispersion in the heavy oil feedstock 708. For example, the static inline mixer 710 and high shear mixer 712 (or another mixing configuration) may be followed by a surge tank 714 with a circulation pump, and optionally one or more multi-stage centrifugal pumps and a second surge tank. Further mixing may be performed using a high energy pump 716 with multiple chambers, in which the catalyst precursor and heavy oil feedstock are agitated and mixed as part of the pumping process itself for delivering the conditioned feedstock to the hydroprocessing reactor.

[0160] The catalyst precursor 702 in the buffer tank 714 continues to diffuse more completely into the heavy oil feedstock 708 through molecular diffusion. Finally, the conditioned feedstock is pumped out of the buffer tank 714 by pump 716 and delivered to a reactor system for heavy oil feedstock hydroprocessing. As described above, the pump 716 may advantageously include a multi-stage high pressure pump. Due to the multiple compression stages, such a pump provides further intense mixing of the conditioned feedstock, ensuring thorough mixing of the catalyst precursor 702 within the feedstock 708 (if such mixing has not already been completed).

[0161] Figure 7B Another exemplary system 700 for intimately mixing a catalyst precursor 702 with a heavy oil feedstock 708 is schematically illustrated. The catalyst precursor 702 is metered by a metering pump 703 to provide the desired flow rate. The catalyst precursor 702 is then mixed with a high boiling hydrocarbon oil diluent 704 in a first static inline mixer 706 to form a diluted catalyst mixture 707.

[0162] The catalyst precursor 702 is mixed with a hydrocarbon oil diluent 704 at a temperature below the temperature at which the bulk of the catalyst precursor 702 begins to decompose. When the hydrocarbon oil diluent 704 is initially too hot, e.g., hotter than the decomposition temperature of the catalyst precursor 702, it first passes through a cooler 705 to reduce its temperature, e.g., to below the decomposition temperature of the catalyst precursor 702. The diluted precursor mixture 707 is then combined with a heavy oil feedstock 708 in a static inline mixer 710 to form a conditioned feedstock in which the precursor 702 is thoroughly mixed with the heavy oil feedstock 708. In the illustrated system 700, the heavy oil feedstock 708 is divided into two streams 708a and 708b for gradual mixing with the diluted precursor mixture 707. A portion of stream 708b is shown as being added directly to a buffer tank 714.

[0163] The diluted precursor mixture 707 is mixed with the first heavy oil feedstock stream 708a in a second low shear static inline mixer 710. The effluent from the mixer 710 comprises a mixture of diluent 704, catalyst precursor 702 and a portion of the heavy oil feedstock 708. The effluent is introduced into a dynamic high shear mixer 712 (e.g., a vessel with a propeller or turbine impeller for providing very turbulent high shear mixing) which is used to intimately mix the catalyst precursor and the heavy oil feedstock. The effluent 713 from the high shear mixer 712 is introduced into a buffer tank 714 along with any remaining heavy oil feedstock 708b.

[0164] Additional equipment may be included downstream to provide more thorough mixing of the catalyst precursor in the heavy oil feedstock. For example, the static inline mixer 710 and the high shear mixer 712 (or other mixing configuration) may be followed by a pump in a buffer tank 714, and / or one or more high pressure multistage centrifugal pumps. For example, the static inline mixer 710 and the high shear mixer 712 (or another mixing configuration) may be followed by a warm buffer tank 714 with multiple circulation pumps (e.g., multiple warm buffer tanks arranged in parallel or in series), and optional equipment 715, such as one or more multistage centrifugal pumps and / or a hot buffer tank. The illustrated system 700 also includes pumps 716a, 716b, 716c arranged in parallel, which will be discussed further below, and which may enable further mixing.

[0165] exist Figure 7B In the mixing system 700, only a portion of the heavy oil feedstock 708 (i.e., stream 708a) is initially mixed with the diluted precursor mixture 707. Although the feedstock 708 is shown as being divided into two streams 708a and 708b, it should be understood that all of the heavy oil feedstock 708 can be added at once (i.e., the feedstock 708 may not be divided), or the feedstock 708 can be divided into more streams for gradual mixing with the catalyst precursor 702. The conditioned feedstock 713 can be introduced into a buffer tank 714 (e.g., one or more warm buffer tanks in series or in parallel with multiple recirculation pumps, followed by optional equipment 715, such as a centrifugal pump and a hot buffer tank) along with any remaining heavy oil feedstock 708b. The buffer tank 714 can be used to more fully diffuse the catalyst precursor 702 into the heavy oil feedstock 708. The buffer tank 714 can provide a residence time between 5 minutes and 60 minutes, or between 10 minutes and 50 minutes, or between 15 minutes and 30 minutes. By diffusion, the catalyst precursor 702 within the buffer tank 714 continues to be more fully dispersed throughout the heavy oil feedstock 708 in preparation for heating and decomposition to form a dispersed catalyst.

[0166] Thereafter, the conditioned feedstock is pumped out of the buffer tank 714 and optional equipment 715 by pumps 716a, 716b, 716c and delivered to a reactor for hydrotreating the heavy oil feedstock. Pumps 716a, 716b, 716c may include a multi-stage high pressure pump. When configured with multiple compression stages (e.g., more than about ten), such pumps 716 provide further intense mixing of the conditioned feedstock, ensuring thorough mixing of the catalyst precursor 702 within the feedstock 708. The conditioned feedstock delivered to the hydrotreating reactor includes catalyst precursors dispersed throughout the heavy oil feedstock down to the molecular level, so that when the precursors are heated and decomposed to form the catalyst, the catalyst particles are advantageously colloidal or molecular sized and highly dispersed.

[0167] The illustrated embodiment advantageously includes three parallel pumps (e.g., pumps 716a, 716b, and 716c). Configuring the system to connect pumps 716 in parallel can increase the flow rate of the conditioned feedstock delivered to the downstream hydroprocessing reactor. In alternative embodiments, the pumps can be configured as series pumps or a combination of series pumps and parallel pumps. Placing the pumps in series effectively increases the number of intense mixing stages through which the conditioned feedstock passes. For example, two series pumps (each pump comprising five stages) can be used instead of a single pump comprising ten stages to achieve substantially the same intimate mixing of the catalyst precursor in the heavy oil feedstock, thereby producing a conditioned feedstock. In either configuration, the result is that the catalyst precursor is uniformly dispersed in the feedstock at the colloidal and / or molecular level, so that when heated, highly dispersed metal sulfide catalyst particles are formed.

[0168] Figures 8A-8B A mixing system 800 is illustrated that is configured to mix a heavy oil feedstock 802 with a diluted precursor mixture 808. The diluted precursor mixture 808 is formed by mixing a catalyst precursor 804 (e.g., an oil-soluble catalyst precursor) with a diluent 806 using one or more mixers known in the art, such as one or more static inline mixers and / or one or more high shear mixers. The heavy oil feedstock 802 and the diluted precursor mixture 808 are fed into a common feed line 810 that is divided into first and second parallel mixing lines 812a, 812b.

[0169] The heavy oil feedstock side stream 836 may optionally be used as a diluent to prepare the diluted precursor mixture 808. A cooler 838 may be used to reduce the temperature of the heavy oil feedstock side stream 836 to prevent premature thermal decomposition of the catalyst precursor 804 in the diluted precursor mixture 808 before it is thoroughly mixed with the heavy oil feedstock 802.

[0170] Each mixing line 812a, 812b may include an upstream valve 814a, 814b that may be selectively opened during operation of the mixing line 812a, 812b, and closed to take the mixing line 812 offline for maintenance and cleaning. When online, the upstream valves 814a, 814b are opened to allow the split streams of the heavy oil feedstock 802 and the diluted precursor mixture 808 to flow through the first and second mixing lines 812a, 812b. In a preferred embodiment, the first and second parallel mixing lines 812a, 812b are designed with symmetrical piping and mixing equipment so that the pressure drop through each parallel mixing line 812 is substantially equal, and equal flow rates between the different mixing lines 812 can be maintained. However, mixing lines 812 of different capacities and flow rates may be used, such as when a single train mixing line is modified to include one or more additional mixing lines.

[0171] exist Fig. 8A In the illustrated mixing system 800, the split streams of the heavy oil feedstock 802 and the diluted precursor mixture 808 are initially mixed by first and second static inline mixers 816a, 816b to produce first and second initially mixed streams, which are then passed through first and second strainers 818a, 818b to remove any unwanted solids from the initially mixed streams. The first and second mixed streams are then fed into first and second high shear mixers 820a, 820b, which provide first and second conditioned feedstock streams. Optional first and second flow meters 822a, 822b may be provided to measure the flow through the first and second mixing lines 812a, 812b downstream of the first and second high shear mixers 820a, 820b.

[0172] Figure 8B Similar to Fig. 8A , except that a common static inline mixer 816 is located on the common feed line 810 and acts as a premixer upstream of the bifurcation of the first and second parallel mixing lines 812a and 812b, and the individual static inline mixers 816a, 816b in the mixing lines 812a and 812b are omitted.

[0173] The first and second flow control devices 824a, 824b are located downstream of the high shear mixers 820a, 820b, respectively. The flow control devices 824a, 824b can provide multiple functions. When the first and second parallel mixing lines 812a, 812b are both online, the flow control devices 824a, 824b will be opened. When one of the mixing lines 812 is offline, the corresponding flow control device 824 can be closed to prevent the pressurized conditioned feedstock from flowing back from the other mixing line 812 that is still in operation. The flow control device 824 of the mixing line 812 that is still in operation can be opened all the time, or can be partially closed to restrict the flow and increase the upstream pressure, thereby causing or causing a portion of the heavy oil feedstock 802 to enter the bypass line 840.

[0174] The conditioned feedstock streams from the first and second mixing lines 812a, 812b are fed into a common discharge line 825 and combined therein to form a common conditioned feedstock stream 846. The common conditioned feedstock stream 846 passes through or through a common flow measurement device 828 (e.g., a flow meter), then through a common flow control device 826 (e.g., a valve), recombines with any heavy oil feedstock from the bypass line 840, and then enters the buffer tank 830.

[0175] The conditioned feedstock side stream 832 from the buffer tank 830 may optionally be used as a diluent to prepare the diluted precursor mixture 808. A cooler 834 may be used to reduce the temperature of the conditioned feedstock side stream 832 to prevent premature thermal decomposition of the catalyst precursor 804 in the diluted precursor mixture 808 before it is thoroughly mixed with the heavy oil feedstock 802.

[0176] When both parallel mixing lines 812a, 812b are online and operational, the common flow control device 826 is open. When one of the mixing lines 812a, 812b is closed and offline, the common flow control device 826 can be partially closed to restrict the flow of material through the common discharge line 825 and increase the upstream pressure to cause or allow a portion of the heavy oil feedstock to enter the bypass line 840. The common flow control device 826 can be used alone or in combination with one of the flow control devices 824 corresponding to the mixing line 812 that is still in operation.

[0177] When both the first and second mixing lines 812a, 812b are online and operating, the bypass line 840 is generally free of the heavy oil feedstock 802 flowing therethrough. However, when one of the parallel mixing lines 812 is shut down and taken offline, the portion of the heavy oil feedstock 802 that is not fed into the remaining online mixing line 812 is caused or allowed to pass through the bypass line 840 to maintain the production of the heavy oil feedstock 802 through the mixing system 800. As described above, the flow of the heavy oil feedstock 802 through the bypass line 840 is caused or caused by partially closing the common flow control valve 826 and / or the mixing line valve 824 of the operating mixing line 812 to restrict the flow through the common discharge line 825. This causes a pressure drop and increases the upstream pressure sufficiently to cause a portion of the heavy oil feedstock 802 to enter the bypass line 840. An optional flow meter 842 on the bypass line 840 measures the flow of the heavy oil feedstock 802 flowing through the bypass line 840. The bypass line 840 is connected to the common discharge line 825 to combine the heavy oil feedstock 808 from the bypass line with a common conditioned feedstock stream 846 downstream of the flow control device 826 and the flow meter 828 .

[0178] The flow rates of the diverted heavy oil feedstock streams through the remaining operating mixing line 812 and the bypass line 840, respectively, can be measured by the common flow meter 828 and the optional bypass flow meter 842, respectively. By adjusting the common flow control valve 826 and / or the bypass line valve 844, the respective flow rates of the materials through the remaining operating mixing line 812 and the bypass line 840 can be adjusted. By measuring the flow rates using flow meters and making adjustments using flow control devices, a desired balance of flow rates through the various lines can be achieved and maintained. In addition to regulating the flow through the bypass line 840, when the first and second mixing lines 812a, 812b are open and operating, the bypass line valve 844 can be closed or partially restricted to balance the line pressures to ensure that the heavy oil feedstock 802 does not pass forward or backward through the bypass line 840.

[0179] Example methods of mixing the catalyst precursor into the heavy oil include using Fig. 8A The hybrid system 800 shown includes:

[0180] (1) mixing a certain amount of catalyst precursor 804 with a certain amount of diluent 806 to form a diluted precursor mixture 808;

[0181] (2) mixing the diluted precursor mixture 808 with the heavy oil feedstock 802 using a plurality of parallel mixing lines 812 to form a plurality of conditioned feedstock streams, each parallel mixing line 812 comprising one or more mixers 816, 820 and at least one valve 814, 824 for regulating flow in the mixing line 812;

[0182] (3) combining the conditioned feed streams in a common discharge line 825 downstream of the parallel mixing line 812 to form a common conditioned feed stream 846;

[0183] (4) stopping flow through mixing line 812 and directing or allowing a portion of heavy oil feedstock 802 to bypass line 840, bypassing parallel mixing line 812, and merging with common conditioned feedstock stream 846 in common discharge line 825; and

[0184] (5) While a portion of the heavy oil feedstock 802 passes through the bypass line 840, at least one other parallel mixing line 812 continues to mix at least a portion of the diluted precursor mixture 808 with the remaining portion of the heavy oil feedstock 802.

[0185] When using Figure 8B As shown in the alternative mixing system 800, the method alternatively includes the step of premixing the diluted precursor mixture 808 with the heavy oil feedstock 802 using a common static inline mixer 816 upstream of the bifurcation of the first and second mixing lines 812a, 812b. The method also omits the use of Fig. 8A Static inline mixers 816a , 816b on first and second mixing lines 812a , 812b are shown mixing the diluted precursor mixture 808 with the heavy oil feedstock 802 .

[0186] The hydroprocessing system may have a defined heavy oil flow rate. When operating both the first and second parallel mixing lines 812a, 812b, it may be advantageous or preferred to evenly split the heavy oil feedstock 802 so that there is a symmetrical (e.g., equal) flow of material through each of the first and second parallel mixing lines 812a, 812b (e.g., half of the defined system flow through each mixing line 812a, 812b).

[0187] When one of the blending lines 812 is closed and taken offline, a portion of the heavy oil feedstock is rerouted through the bypass line 840 to maintain the same or similar defined flow rate of the heavy oil feedstock 802 through the blending system 800. By way of example and not limitation, for a blending system 800 with defined flow rates, the flow rates of the heavy oil feedstock 802 through the bypass line 840 and the remaining online blending lines 812 may be the same (e.g., approximately half of the defined system flow rate through each line). In a preferred embodiment, the flow rate of the heavy oil feedstock 802 through the remaining online blending lines 812 is increased to above half of the defined flow rate, and the flow rate of the heavy oil feedstock 802 through the bypass line 840 is decreased to below half of the defined flow rate.

[0188] Alternatively, the flow rate of the heavy oil feedstock 802 through the bypass line 840 may be greater than the flow rate through the remaining online mixing line 812. For example, the flow rate through the bypass line 840 may be greater than half of the defined system flow rate. In order to maintain the same or similar flow rate of the heavy oil feedstock through the system, the corresponding flow rate through the remaining online mixing line 812 may be reduced to less than half of the defined system flow rate.

[0189] In the case where the heavy oil feedstock side stream 836 is used as a diluent to prepare the diluted precursor mixture 808, and the flow rate of the heavy oil feedstock 802 through the mixing system 800 is about 100 tons / hour, the amount of the heavy oil feedstock side stream 836 can be up to about 10 tons / hour, or up to about 5 tons / hour (or between about 0-10 tons / hour, or about 0-5 tons / hour, depending on the conditions within the mixing system 800). In the case where the flow rate of the heavy oil feedstock 802 through the mixing system 800 is less than or greater than 100 tons / hour, the flow rate of the heavy oil feedstock side stream 836 used as a diluent to prepare the diluted precursor mixture 808 can be up to about 10%, or about 5% of the total flow rate (or about 0.1-10%, or about 0.5-5%, of the total flow rate, depending on the conditions within the mixing system 800).

[0190] In the case where the conditioned heavy oil feedstock side stream 832 is used as a diluent to prepare the diluted precursor mixture 808, and the flow rate of the heavy oil feedstock 802 through the mixing system 800 is about 100 tons / hour, the amount of the conditioned heavy oil feedstock side stream 832 can be up to about 10 tons / hour, or up to about 5 tons / hour (or about 0-10 tons / hour, or about 0-5 tons / hour, depending on the conditions within the mixing system 800). In the case where the flow rate of the heavy oil feedstock 802 through the mixing system 800 is less than or greater than 100 tons / hour, the flow rate of the conditioned heavy oil feedstock side stream 832 used as a diluent to prepare the diluted precursor mixture 808 can be up to about 10% of the total flow rate, or about 5% of the total flow rate (or about 0.1-10%, or about 0.5-5% of the total flow rate, depending on the conditions within the mixing system 800).

[0191] In some embodiments, dispersed metal sulfide catalyst particles are formed in situ in the entire heavy oil added to the hydroprocessing reactor. This can be achieved using the disclosed mixing method and system, first mixing the catalyst precursor with a diluent to form a diluted precursor mixture, then mixing the diluted precursor mixture with the entire heavy oil in multiple parallel mixing lines to form parallel conditioned feedstock streams, which are periodically combined with the heavy oil feedstock from the bypass line into a common conditioned feedstock stream, and then heated to decompose the catalyst precursor and cause or allow the catalyst metal to react with sulfur and / or sulfur-containing molecules in and / or added to the heavy oil to form dispersed metal sulfide catalyst particles in situ.

[0192] The catalyst precursor may be oil soluble and have a decomposition temperature in the range of about 100°C to about 350°C, or in the range of about 150°C to about 300°C, or in the range of about 175°C to about 250°C. Exemplary catalyst precursors include organometallic complexes or compounds, more specifically oil soluble compounds or complexes of transition metals and organic acids, having a decomposition temperature or decomposition temperature range high enough to avoid substantial decomposition when mixed with heavy oil feedstocks under suitable mixing conditions. When the catalyst precursor is mixed with a hydrocarbon oil diluent, it is advantageous to maintain the diluent below the temperature at which significant decomposition of the catalyst precursor occurs. One skilled in the art can select a mixing temperature profile that allows for thorough mixing of the selected precursor composition without significant decomposition prior to in situ formation of dispersed metal sulfide catalyst particles.

[0193] Example catalyst precursors include, but are not limited to, 2-ethylhexanoic acid molybdenum, octanoic acid molybdenum naphthenate, vanadium naphthenate, octanoic acid vanadium, hexacarbonyl molybdenum, hexacarbonyl vanadium, and pentacarbonyl iron. Other catalyst precursors include molybdenum salts comprising a plurality of cationic molybdenum atoms and a plurality of carboxylate anions of at least 8 carbon atoms, and being at least one of (a) aromatic, (b) alicyclic, or (c) branched unsaturated aliphatic. For example, each carboxylate anion may have 8 to 17 carbon atoms or 11 to 15 carbon atoms. Examples of carboxylate anions that meet at least one of the aforementioned categories include carboxylate anions derived from carboxylic acids selected from the group consisting of: 3-cyclopentylpropionic acid, cyclohexanebutyric acid, biphenyl-2-carboxylic acid, 4-heptylbenzoic acid, 5-phenylpentanoic acid, geranic acid (3,7-dimethyl-2,6-octadienoic acid), and combinations thereof.

[0194] In other embodiments, carboxylate anions suitable for preparing oil-soluble, thermally stable platinum catalyst precursor compounds are derived from carboxylate anions of carboxylic acids selected from the group consisting of 3-cyclopentylpropionic acid, cyclohexanebutyric acid, biphenyl-2-carboxylic acid, 4-heptylbenzoic acid, 5-phenylpentanoic acid, geranic acid (3,7-dimethyl-2,6-octadienoic acid), 10-undecenoic acid, dodecanoic acid, and combinations thereof. It has been found that platinum catalyst precursors prepared using carboxylate anions derived from the foregoing carboxylic acids have improved thermal stability.

[0195] Catalyst precursors with higher thermal stability may have a first decomposition temperature above 210° C., above about 225° C., above about 230° C., above about 240° C., above about 275° C., or above about 290° C. Such catalyst precursors may have a peak decomposition temperature above 250° C., or above about 260° C., or above about 270° C., or above about 280° C., or above about 290° C., or above about 330° C.

[0196] In the case where the heavy oil feedstock is solid or extremely viscous at room temperature, it may be advantageous to heat such feedstocks to soften them and produce a feedstock with a sufficiently low viscosity to allow the oil-soluble catalyst precursor to be well mixed into the feedstock. Generally speaking, reducing the viscosity of the heavy oil feedstock will reduce the time required for the oil-soluble precursor composition to be fully and intimately mixed in the feedstock. However, it may also result in premature decomposition of the catalyst precursor. A catalyst precursor may be selected that has a decomposition temperature suitable for a given heavy oil feedstock.

[0197] After the catalyst precursor has been fully mixed in the whole heavy oil to produce the conditioned feedstock, the composition is heated to cause the decomposition of the catalyst precursor to release the catalyst metal therefrom, thereby making or allowing the catalyst metal to react with the sulfur in and / or added to the heavy oil, and forming active metal sulfide catalyst particles in situ. The metal from the catalyst precursor can initially form a metal oxide, which then reacts with the sulfur in the heavy oil to produce a metal sulfide compound, which forms the final active catalyst. In the case where the heavy oil contains enough or excessive sulfur, the final activated catalyst can be formed in situ by heating the feedstock to a temperature sufficient to release sulfur therefrom. In some cases, sulfur can be released at the same temperature at which the catalyst precursor decomposes. In other cases, further heating to a higher temperature may be required. Hydrogen sulfide gas can be added to the heavy oil lacking enough sulfur to form active metal sulfide catalyst particles.

[0198] If the catalyst precursor is thoroughly mixed in the heavy oil, at least most of the released metal ions will be sufficiently protected or shielded from the influence of other metal ions so that they can form a molecularly dispersed catalyst when reacting with sulfur to form metal sulfides. In some cases, slight agglomeration may occur, resulting in colloidal-sized catalyst particles. However, it is believed that before the catalyst precursor is thermally decomposed, taking care to thoroughly mix the catalyst precursor throughout the feedstock can produce individual catalyst molecules, rather than colloidal particles. Simply mixing the catalyst precursor with the feedstock without sufficient mixing usually results in the formation of large agglomerated metal sulfides of micrometer size or larger.

[0199] To form dispersed metal sulfide catalyst particles, the conditioned feedstock is heated to a temperature in the range of about 275°C (527°F) to about 450°C (842°F), or in the range of about 310°C (590°F) to about 430°C (806°F), or in the range of about 330°C (626°F) to about 410°C (770°F).

[0200] The concentration of the catalyst metal provided by the metal sulfide catalyst particles dispersed in the heavy oil can depend on the type of reactor used. In the case where the dispersed metal sulfide catalyst is used together with a solid supported catalyst (e.g., an ebullating bed reactor or a fixed bed reactor), the concentration of the heavy oil and any diluent can be in the range of about 1 ppm to about 150 ppm by weight, or in the range of about 5 ppm to about 95 ppm by weight, or in the range of about 10 ppm to about 75 ppm by weight. In the case where the dispersed metal sulfide catalyst is the only catalyst used (e.g., a slurry reactor), its concentration can be in the range of about 30 ppm to about 1000 ppm by weight of the heavy oil and any diluent, or in the range of about 50 ppm to about 500 ppm by weight, or in the range of about 75 ppm to about 300 ppm by weight.

[0201] In the case where the heavy oil contains a large number of asphaltene molecules, the dispersed metal sulfide catalyst particles may preferentially bind to or remain in close proximity with the asphaltene molecules. Asphaltene molecules may have a greater affinity for the metal sulfide catalyst particles because asphaltene molecules are generally more hydrophilic and less hydrophobic than other hydrocarbons contained in the heavy oil. Because the metal sulfide catalyst particles tend to be hydrophilic, individual particles or molecules will tend to migrate toward the more hydrophilic portions or molecules in the heavy oil.

[0202] Although the highly polar nature of the metal sulfide catalyst particles causes or allows them to bind to asphaltene molecules, the general incompatibility between highly polar catalyst compounds and hydrophobic heavy oils makes it necessary to perform the aforementioned adequate or thorough mixing of the catalyst precursor in the feedstock prior to decomposition and in situ formation of active catalyst particles. Because the metal catalyst compounds are highly polar, they cannot be effectively dispersed in the heavy oil if added directly. In fact, the formation of smaller active catalyst particles leads to a larger number of catalyst particles, thereby providing more evenly distributed catalyst sites throughout the heavy oil. It also increases the surface area of ​​the catalyst.

[0203] Thorough mixing of the catalyst precursor with the heavy oil feedstock prior to thermal decomposition of the catalyst precursor and formation of dispersed metal sulfide catalyst particles significantly reduces the rate of equipment fouling, which rate can be measured by at least one of the following: (i) the frequency of required heat exchanger cleaning; (ii) the frequency of switching to a backup heat exchanger; (iii) the frequency of filter replacement; (iv) the frequency of coarse filter cleaning or replacement; (v) the rate of decrease in equipment surface temperature, the equipment including equipment selected from the group consisting of heat exchangers, separators, or distillation columns; (vi) the rate of increase in furnace tube metal temperature; (vii) the rate of increase in the calculated fouling thermal resistance coefficient of heat exchangers and furnaces; (viii) the rate of increase in heat exchanger pressure differentials; (ix) the frequency of cleaning atmospheric and / or vacuum distillation columns; or (x) the frequency of maintenance turnover.

[0204] V. Examples

[0205] Comparative Example 1

[0206] Molybdenum 2-ethylhexanoate has a decomposition temperature of about 150°C and is used as an oil-soluble catalyst precursor in a heavy oil feedstock. The catalyst precursor is added directly to the feed line of the heavy oil feedstock before feeding the heavy oil feedstock into an ebullated bed reactor containing a heterogeneous ebullated bed catalyst. When the catalyst precursor is added, the heavy oil feedstock is at a temperature of about 200°C, and no mixing equipment is used before feeding the heavy oil feedstock into the hydroprocessing reactor.

[0207] The catalyst precursor thermally decomposes and forms metal catalyst agglomerates with a size of 1-300 μm. The catalyst agglomerates have low surface area and low catalytic activity. Instead of improving the performance of the ebullating bed reactor, they lead to additional fouling and deposit formation.

[0208] Comparative Example 2

[0209] This comparative example is similar to comparative example 1, except that a series of mixers (including a static inline mixer and a high shear mixer, followed by a buffer tank and a pressure pump) are used to mix the catalyst precursor with the heavy oil feedstock. Although the catalyst precursor is mixed into the heavy oil feedstock, it thermally decomposes before sufficient mixing, resulting in the formation of larger catalyst particles with a size of 1-150 μm. The catalyst particles have low surface area and low catalytic activity. Instead of improving the performance of the ebullating bed reactor, they cause additional fouling and deposit formation.

[0210] Comparative Example 3

[0211] The catalyst precursor is not mixed directly into the bulk of the heavy oil feedstock, but is first premixed with a side stream (5 volume %) of the heavy oil feedstock as a diluent to form a diluted precursor mixture, which is then mixed into the remainder (95 volume %) of the heavy oil feedstock. Since the temperature of the side stream of the heavy oil feedstock is higher than the decomposition temperature of the catalyst precursor, the catalyst precursor undergoes thermal decomposition before being fully mixed in the diluent, thereby forming larger catalyst particles with a size of 1-150 μm. The catalyst particles have a low surface area and low catalytic activity. Instead of improving the performance of the ebullating bed reactor, they lead to additional fouling and deposit formation.

[0212] Comparative Example 4

[0213] The catalyst precursor is not mixed directly into the heavy oil feedstock, but is first premixed with a medium boiling hydrocarbon at a temperature below its decomposition temperature to form a diluted precursor mixture. The diluted precursor mixture is then mixed into the heavy oil feedstock to form a conditioned feedstock, which is then heated to decompose the catalyst precursor and form active metal sulfide catalyst particles in situ. The resulting dispersed metal sulfide catalyst particles are less than 1 μm in size and have good catalytic activity. However, the process of forming the diluted precursor mixture requires the use of valuable hydrocarbon materials that are either in short supply, are required for other processes in the refinery, or may be sold at uneconomical prices, making their use as diluents for the catalyst precursor uneconomical.

[0214] Example 5

[0215] Rather than premixing the catalyst precursor with the mid-boiling hydrocarbons to form a diluted precursor mixture, the catalyst precursor is premixed with a side stream (5% by volume) of the heavy oil feedstock as a diluent to form a diluted precursor mixture, which is then mixed into the remainder (95% by volume) of the heavy oil feedstock. Prior to mixing with the catalyst precursor, the heavy oil feedstock side stream is cooled to a temperature of 150° C., which is close to the decomposition temperature of the catalyst precursor, and thus does not cause more than 20% of the catalyst precursor to decompose before the catalyst precursor is fully mixed in the diluent.

[0216] The diluted precursor mixture is mixed into a heavy oil feedstock to form a conditioned feedstock, which is then heated to decompose the catalyst precursor and form active metal sulfide catalyst particles in situ. Most of the dispersed metal sulfide catalyst particles are less than 1 μm in size and have good catalytic activity.

[0217] Example 6

[0218] This example is similar to Example 5, except that prior to mixing with the catalyst precursor, the heavy oil feedstock side stream is cooled to a temperature of 125°C, which is slightly below the decomposition temperature of the catalyst precursor and therefore does not result in more than 5% decomposition of the catalyst precursor before the catalyst precursor is fully mixed in the diluent.

[0219] The diluted precursor mixture is mixed into a heavy oil feedstock to form a conditioned feedstock, which is then heated to decompose the catalyst precursor and form active metal sulfide catalyst particles in situ. The dispersed metal sulfide catalyst particles are less than 1 μm in size and have excellent catalytic activity.

[0220] Example 7

[0221] This example is similar to Examples 5 and 6, except that the heavy oil feedstock side stream is cooled to a temperature of 75-95°C prior to mixing with the catalyst precursor, which is well below the decomposition temperature of the catalyst precursor and therefore does not result in significant decomposition of the catalyst precursor before the catalyst precursor is thoroughly mixed in the diluent.

[0222] The diluted precursor mixture is mixed into a heavy oil feedstock to form a conditioned feedstock, which is then heated to decompose the catalyst precursor and form active metal sulfide catalyst particles in situ. The dispersed metal sulfide catalyst particles are less than 1 μm in size and have excellent catalytic activity.

[0223] Example 8

[0224] This example is similar to Example 7, except that a side stream of conditioned heavy oil feedstock is used as a high boiling hydrocarbon diluent. The temperature of the side stream of conditioned heavy oil feedstock is about 225° C. Prior to mixing with the catalyst precursor, the conditioned feedstock side stream is cooled to a temperature of 75-95° C., which is well below the decomposition temperature of the catalyst precursor and therefore does not cause significant decomposition of the catalyst precursor before the catalyst precursor is thoroughly mixed in the diluent.

[0225] The diluted precursor mixture is mixed into a heavy oil feedstock to form a conditioned feedstock, which is then heated to decompose the catalyst precursor and form active metal sulfide catalyst particles in situ. The dispersed metal sulfide catalyst particles are less than 1 μm in size and have excellent catalytic activity.

[0226] Example 9

[0227] This example is similar to Examples 7 and 8, except that vacuum tower bottoms are used as the high boiling hydrocarbon diluent. The initial temperature of the vacuum tower bottoms product is about 250° C. Before mixing with the catalyst precursor, the vacuum tower bottoms product is cooled to a temperature of 75-95° C., which is much lower than the decomposition temperature of the catalyst precursor, and therefore does not cause significant decomposition of the catalyst precursor before the catalyst precursor is completely mixed in the diluent.

[0228] The diluted precursor mixture is mixed into a heavy oil feedstock to form a conditioned feedstock, which is then heated to decompose the catalyst precursor and form active metal sulfide catalyst particles in situ. The dispersed metal sulfide catalyst particles are less than 1 μm in size and have excellent catalytic activity.

[0229] Example 10

[0230] This example is similar to Examples 7-9, except that a deasphalted oil product is used as a high boiling hydrocarbon diluent. The initial temperature of the deasphalted oil product is about 200° C. Before mixing with the catalyst precursor, the deasphalted oil product is cooled to a temperature of 75-95° C., which is much lower than the decomposition temperature of the catalyst precursor, and therefore does not cause significant decomposition of the catalyst precursor before the catalyst precursor is completely mixed in the diluent.

[0231] The diluted precursor mixture is mixed into a heavy oil feedstock to form a conditioned feedstock, which is then heated to decompose the catalyst precursor and form active metal sulfide catalyst particles in situ. The dispersed metal sulfide catalyst particles are less than 1 μm in size and have excellent catalytic activity.

[0232] Embodiment 11

[0233] This example is similar to any one of Examples 7-10, except that a high boiling hydrocarbon material is used together with a certain amount of a medium boiling hydrocarbon material to form a high boiling hydrocarbon diluent mixture. Before mixing with the catalyst precursor, the high boiling hydrocarbon material is cooled to a temperature of 75-95°C, which is much lower than the decomposition temperature of the catalyst precursor, and therefore does not cause significant decomposition of the catalyst precursor before the catalyst precursor is completely mixed in the diluent.

[0234] The diluted precursor mixture is mixed into a heavy oil feedstock to form a conditioned feedstock, which is then heated to decompose the catalyst precursor and form active metal sulfide catalyst particles in situ. The dispersed metal sulfide catalyst particles are less than 1 μm in size and have excellent catalytic activity.

[0235] The present invention may be implemented in other specific forms without departing from the spirit or essential features of the present invention. The described embodiments are considered to be illustrative and non-restrictive in all aspects. Therefore, the scope of the present invention is represented by the appended claims rather than the preceding description. All changes within the meaning and scope of the equivalents of the claims are included within the scope of the claims.

Claims

1. A method for mixing a catalyst precursor into heavy oil, comprising: providing a catalyst precursor having a decomposition temperature; providing a high boiling hydrocarbon diluent consisting of one or more high boiling hydrocarbons and optionally one or more medium boiling hydrocarbons, the high boiling hydrocarbon diluent having an initial temperature higher than the decomposition temperature of the catalyst precursor; cooling the high boiling point hydrocarbon diluent to a temperature below the decomposition temperature of the catalyst precursor; mixing a catalyst precursor with a high boiling hydrocarbon diluent to form a diluted precursor mixture; and The diluted precursor mixture is mixed with a heavy oil feedstock to form a conditioned feedstock.

2. The method of claim 1, wherein the decomposition temperature of the catalyst precursor is in the range of about 150°C to about 200°C, and before the catalyst precursor is mixed with the high boiling point hydrocarbon diluent, the high boiling point hydrocarbon diluent is cooled to a temperature of 150°C or below, or in the range of about 75°C to about 150°C, or in the range of about 75°C to about 125°C, or in the range of about 75°C to about 95°C.

3. The method of claim 1, wherein the decomposition temperature of the catalyst precursor is in the range of about 125°C to about 150°C, and before the catalyst precursor is mixed with the high boiling point hydrocarbon diluent, the high boiling point hydrocarbon diluent is cooled to 125°C or below, or in the range of about 75°C to about 125°C, or in the range of about 75°C to about 95°C.

4. The process according to any one of claims 1 to 3, wherein the high boiling hydrocarbon diluent comprises a portion of a heavy oil feedstock.

5. The process according to any one of claims 1 to 4, wherein the high boiling hydrocarbon diluent comprises a portion of the conditioned feedstock.

6. The process of any one of claims 1 to 5, wherein the high boiling hydrocarbon diluent comprises a vacuum bottoms product, such as a recycled vacuum bottoms from one or more hydroprocessing reactors that hydroprocess the conditioned feedstock or its conversion products.

7. The process of any one of claims 1 to 6, wherein the high boiling hydrocarbon diluent comprises a deasphalted oil product.

8. A process according to any one of claims 1 to 7, wherein the high boiling hydrocarbon diluent comprises a thermal conversion product, such as a visbreaker bottoms.

9. The method of any one of claims 1 to 8, wherein the high boiling hydrocarbon diluent has a boiling point of at least about 350°C, or at least about 400°C, or at least about 450°C, or at least about 500°C, or at least about 524°C.

10. The method of any one of claims 1 to 9, wherein a portion of the high boiling hydrocarbon diluent comprises medium boiling hydrocarbon materials having a boiling point in the range of about 200°C to about 524°C.

11. The method of claim 10, wherein the medium-boiling hydrocarbon material comprises at least one of vacuum gas oil, decant oil, cycle oil, or atmospheric gas oil.

12. A process according to any one of claims 1 to 11 wherein the catalyst precursor and boiling hydrocarbon diluent are mixed using one or more static inline mixers and optionally one or more high shear mixers.

13. The process of any one of claims 1 to 12, wherein the diluted precursor mixture and heavy oil feedstock are mixed using one or more static inline mixers and one or more high shear mixers.

14. The method of any one of claims 1 to 13, further comprising feeding the conditioned feedstock into a buffer tank.

15. The method of any one of claims 1 to 14, further comprising heating the conditioned feedstock to thermally decompose at least a portion of the catalyst precursor and react with sulfur to form dispersed catalyst sulfide particles in situ in the heavy oil feedstock.

16. A system for mixing a catalyst precursor into a heavy oil feedstock, comprising: a catalyst precursor supply line that provides a catalyst precursor at a temperature below a decomposition temperature of the catalyst precursor; at least one diluent supply line providing a high boiling hydrocarbon diluent consisting of one or more high boiling hydrocarbons and optionally one or more medium boiling hydrocarbons, the diluent supply line providing the high boiling hydrocarbon diluent having an initial temperature above the decomposition temperature of the catalyst precursor; at least one cooler configured to cool the high boiling point hydrocarbon diluent to a temperature below a decomposition temperature of the catalyst precursor; at least one premixer configured to receive the catalyst precursor and mix it with a high boiling hydrocarbon diluent to form a diluted precursor mixture; and At least one mixer is configured to mix the diluted precursor mixture with the heavy oil feedstock to form a conditioned feedstock.

17. The system of claim 16, wherein the at least one diluent supply line is configured to provide a side stream of the heavy oil feedstock.

18. The system of claim 16 or 17, wherein the at least one diluent supply line is configured to provide a side stream of the conditioned feedstock.

19. The system of any one of claims 16 to 18, wherein the at least one diluent supply line is configured to provide a vacuum bottoms product.

20. The system of any one of claims 16 to 19, wherein the at least one premixer comprises at least one static inline mixer.

21. The system of any one of claims 16 to 20, wherein the at least one mixer comprises at least one high shear mixer and optionally a static inline mixer and / or a strainer.

22. The system of any one of claims 16 to 21, further comprising a surge tank configured to receive the conditioned feedstock, the surge tank causing or allowing catalyst precursor to further mix throughout the heavy oil feedstock.

23. The system of any one of claims 16 to 22, further comprising a heater configured to heat the conditioned feedstock and thermally decompose at least a portion of the catalyst precursor and react with sulfur to form dispersed catalyst sulfide particles in situ in the heavy oil feedstock.

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