EA041150B1 - METHOD OF MODERNIZATION OF BOILING-BED REACTOR FOR MINOR SLUDGE POLLUTION - Google Patents

Description

State of the art

1) The field of technology.

The invention relates to heavy oil hydrotreating methods and systems, such as fluidized bed hydrotreating methods and systems, which use a two-way catalyst system and operate with little sediment fouling.

2) Appropriate technology.

There is an ever-increasing need for more efficient use of low-quality heavy oil feedstocks and the extraction of energy potential from them. Low quality feedstocks are characterized as including relatively high amounts of hydrocarbons that nominally boil at 524°C (975°F) or higher. They also contain relatively high concentrations of sulfur, nitrogen and/or metals. The high boiling fractions produced from these inferior feedstocks typically have a high molecular weight (often denoted by higher density and viscosity) and/or a low hydrogen/carbon ratio due to the presence of high concentrations of undesirable components including asphaltenes and coke residue. Asphaltenes and coke residue are difficult to handle and typically cause fouling of traditional catalysts and hydrotreating equipment because they promote coke and sludge formation.

In this fluidized bed system, the productivity of the converted products is often limited by fouling. When attempts are made to increase productivity beyond a certain practical limit, the fouling rate of some heat exchangers or other process equipment becomes too fast, requiring more frequent maintenance and cleaning shutdowns. Typically, the refinery will determine the ratio of the observed equipment fouling rate to the measurements of sludge formation and reach an operational sludge limit above which the refinery will avoid operating a fluidized bed hydrocracker. In addition, sedimentation and equipment fouling impose restrictions on the further processing of high-boiling fractions.

Low quality heavy oil feedstocks, which contain higher concentrations of asphaltenes, coke residue, sulfur, nitrogen and metals, include heavy oil, tar sands and bottoms left over from a conventional process unit. Bottoms (or tar) can refer to the bottoms of the atmospheric column and to the bottoms of the vacuum column. The bottoms of the atmospheric column may have an initial boiling point of at least 343°C (650°F) although it is understood that the boiling point of fractions may vary among refineries and reach 380°C (716°F). Vacuum column bottoms (also known as residual pitch or vacuum bottoms) may have a boiling point of at least 524°C (975°F) although it is understood that the boiling point of fractions may vary among refineries and reach 538°C (1000°F) or even 565°C (1050°F).

By comparison, Alberta light oil contains approximately 9% by volume vacuum residue, while Lloydminster heavy oil contains approximately 41% vacuum residue by volume, Cold Lake bitumen contains approximately 50% vacuum residue by volume, and Athabasca bitumen contains approximately 51% vacuum residue by volume. remainder. As a side comparison, relatively light oil such as Dansk Blend from the North Sea region contains approximately 15% vacuum residue, while lower quality European oils such as Urals contain over 30% vacuum residue and oils such as Arab Medium (Arabian Medium) contains even higher from about 40% vacuum residue. These examples highlight the importance of being able to convert vacuum residues when using low grade crude oils.

Turning heavy oil into useful end products involves extensive processing, including lowering the boiling point of 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 atmospheric bottoms upgrade catalysts include fixed bed hydrotreating, fluidized bed hydrotreating, and moving bed hydrotreating. Non-catalytic upgrading processes for upgrading vacuum column bottoms include thermal cracking such as delayed coking, flexcoking, light cracking, and solvent extraction.

The essence of the invention

Disclosed herein are methods for retrofitting a fluidized bed hydrotreating system to produce low sludge fouling. Also disclosed are upgraded fluidized bed hydrotreating systems to produce negligible sludge fouling. The disclosed methods and systems include the use of a two-way catalyst system consisting of a supported solid catalyst and well-dispersed (eg, homogeneous) catalyst particles. The two-way catalyst system allows a fluidized bed reactor to be operated at the same or higher rate for a heavy oil of a given quality because the sludge that forms causes little equipment fouling compared to the sludge generated in the same reactor using only solid catalyst at carrier.

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In some embodiments, a method for upgrading a fluidized bed hydrotreating system to produce low sludge fouling comprises: (1) operating a fluidized bed reactor using a heterogeneous heavy oil hydrotreating catalyst under initial conditions, including initial converted product productivity, initial sludge formation rate, and/ or concentration in the process stream and the initial contamination rate of the equipment; (2) then upgrading the fluidized bed reactor to operate with a two-way catalyst system consisting of dispersed metal sulfide catalyst particles and a heterogeneous catalyst; and (3) operating an upgraded fluidized bed reactor using a two-way catalyst system with little sludge fouling resulting in little equipment fouling at a given sludge rate and/or concentration compared to operating the fluidized bed reactor under initial conditions.

In some embodiments, operating an upgraded fluidized bed reactor using a two-way catalyst system to produce negligible sludge fouling comprises at least one of: (i) reducing the sludge formation rate and/or concentration in the process stream and reducing the equipment fouling rate to a greater extent. degree than the reduction in the rate of precipitation and/or concentration; (ii) maintaining an appropriate sludge rate and/or concentration while reducing equipment fouling rates; or (iii) increasing the rate of sedimentation and/or concentration without increasing the rate of equipment fouling.

In some embodiments, operating an upgraded fluidized bed reactor using a two-way catalyst system to produce negligible sludge fouling comprises: (i) producing converted products at the same or similar rate as the initial rate of converted products during initial operation; (ii) sludge formation at a reduced rate and/or concentration in the process stream compared to the initial sludge rate and/or concentration during initial operation; and (iii) the fouling of the equipment occurs at a reduced rate compared to the initial fouling rate of the equipment when operating under initial conditions and where the fouling rate of the equipment is reduced to a greater extent than the reduction in sedimentation rate and/or concentration.

In some embodiments, operating an upgraded fluidized bed reactor using a two-way catalyst system to produce negligible sludge fouling comprises: (i) producing converted products at a higher rate than the initial rate of converted products during initial operation; (ii) deposit formation at a rate and/or concentration in the process stream that does not exceed the initial deposit rate and/or concentration during initial operation; and (iii) equipment fouling occurs at a reduced rate compared to the initial equipment fouling rate during initial operation.

In some embodiments, operating an upgraded fluidized bed reactor using a two-way catalyst system to produce negligible sludge fouling comprises: (i) producing converted products at a rate greater than the initial rate of converted products during initial operation; (ii) deposit formation at a higher rate and/or concentration in the process stream than during initial operation; and (iii) equipment fouling occurs at a rate that does not exceed the initial fouling rate of the equipment during initial operation.

In some embodiments, converted product yield can be increased by operating the upgraded fluidized bed reactor using a two-way catalyst system of at least one of: (i) higher temperature and higher conversion at the same or similar throughput as operating in initial conditions; (ii) higher temperature and higher throughput at the same or similar conversion as in the case of initial operation; or (iii) higher temperature, higher throughput and higher conversion, as in the case of initial operation. In some embodiments, the increase in converted product yield may include an increase in throughput of at least 2.5%, at least 5%, at least 10%, or at least 20% when operating the upgraded boiling water reactor. layer, compared with the operation in the initial conditions. In some embodiments, increasing the yield of converted products may include increasing conversion by at least 2.5%, at least 5%, at least 7.5%, at least 10%, or at least 15% in the operation of a modernized fluidized bed reactor, compared with operation in the initial conditions. In some embodiments, increasing the yield of converted products may include increasing the temperature by at least 2.5°C, at least 5°C, at least 7.5°C, or at least

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10°C during operation of the upgraded fluidized bed reactor compared to operation under initial conditions.

In some embodiments, the equipment fouling rate can be determined during initial operation and during operation of the upgraded fluidized bed reactor using a two-way catalyst system of at least one of: (i) the frequency of heat exchanger cleaning required; (ii) frequency of switching to spare coils; (iii) frequency of filter changes; (iv) frequency of cleaning or replacement of the coarse filter; (v) the rate of decrease in skin temperatures in equipment, including equipment selected from heat exchangers, separators or distillation columns; (vi) the rate of increase in temperature of the chimney metal; (vii) the rate of increase of the calculated fouling thermal resistance factors for heat exchangers and furnaces; (viii) the rate of increase in pressure drop across the heat exchangers; (ix) cleaning frequency of atmospheric and/or vacuum distillation columns; or (x) frequency of major repairs.

In some embodiments, sludge formation can be determined during initial operation and during operation of the upgraded fluidized bed reactor using a two-way catalyst system of at least one of: (i) an absolute sludge formation rate (eg, amount per unit time); or (ii) the concentration of sludge in at least one process stream. In some embodiments, the sediment concentration can be measured in at least one process stream selected from atmospheric residue, atmospheric distillation column bottom residue, vacuum residue, vacuum distillation column bottom residue, atmospheric column feed, hot low pressure separator product , product of liquid fuel or VAT residue of the vacuum column after adding distillate oil products.

In some embodiments, after retrofitting a fluidized bed reactor with a two-way catalyst system, the sludge rate and/or concentration in the process stream is maintained or increased from the initial sludge rate and/or concentration, and the equipment fouling rate is reduced by at least 5 , 25, 50 or 75% compared to the initial equipment contamination rate.

In some embodiments, after upgrading to a two-way catalyst system, the fouling rate is increased by at least 2%, 10%, 20%, or 33% from the initial fouling rate, and the equipment fouling rate is maintained or reduced from the initial fouling rate of the equipment.

In some embodiments, after upgrading to a two-way catalyst system, the sludge concentration in the process stream is increased by at least 2%, 10%, 20%, or 33% from the initial sludge concentration and the equipment fouling rate is maintained or reduced from the initial equipment fouling rate. .

In some embodiments, after upgrading to a two-way catalyst system, the sludge rate is reduced by at least 2%, 10%, 30%, or 50% of the initial sludge rate, and the equipment fouling rate is reduced by an even greater percentage than the percent reduction in sludge rate. sludge compared to the initial equipment fouling rate.

In some embodiments, after upgrading to a two-way catalyst system, the sludge concentration in the process stream is reduced by at least 2%, 10%, 30%, or 50% of the initial sludge concentration, and the equipment fouling rate is reduced by an even greater percentage than the percentage reduction in concentration. sludge compared to the initial equipment fouling rate.

In some embodiments, the dispersed metal sulfide catalyst particles are less than 1 micron 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.

In some embodiments, the dispersed metal sulfide catalyst particles are formed in situ in the heavy oil from the catalyst precursor. By way of example, and not limitation, dispersed metal sulfide catalyst particles can be formed by agitating the catalyst precursor throughout a heavy oil to thermally decompose the catalyst precursor and form active metal sulfide catalyst particles. As a further example, the methods may include mixing the catalyst precursor with a hydrocarbon diluent to form a dilute precursor mixture, mixing the dilute precursor mixture with a heavy oil to form a conditioned heavy oil, and heating the conditioned heavy oil to decompose the catalyst precursor and form dispersed metal sulfide catalyst particles in situ. in heavy oil.

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These and other advantages and features of the present invention will become more apparent from the following description and the appended claims, or may be learned by practice of the present invention as set forth below.

Brief description of the drawings

For the purpose of further clarifying the above and other advantages and features of the present invention, a more specific description of the invention will be presented by reference to its specific embodiments, which are illustrated in the accompanying drawings. It is to be understood that these drawings only show exemplary embodiments of the invention and are therefore not intended to limit its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, where

In FIG. 1 depicts the putative molecular structure of asphaltene.

In FIG. 2A and 2B schematically illustrate exemplary fluidized bed reactors.

In FIG. 2C schematically illustrates an exemplary fluidized bed hydrotreating system comprising multiple fluidized bed reactors.

In FIG. 2D schematically illustrates an exemplary fluidized bed hydrotreating system comprising multiple fluidized bed reactors and an intermediate separator between the two reactors.

In FIG. 3A is a block diagram illustrating an exemplary process for retrofitting a fluidized bed reactor to achieve low sludge fouling.

In FIG. 3B is a flow diagram illustrating an exemplary process for upgrading a fluidized bed reactor to reduce equipment fouling rates rather than reducing fouling rates and/or process stream concentrations.

In FIG. 3C is a flow diagram illustrating an exemplary process for upgrading a fluidized bed reactor to reduce equipment fouling rates at the same sludge rate and/or process stream concentration.

In FIG. 3D is a block diagram illustrating an exemplary method for upgrading a fluidized bed reactor to increase the rate of sludge formation and/or the concentration of sludge in the process stream without increasing the rate of equipment fouling.

In FIG. 4 schematically illustrates an exemplary fluidized bed hydrotreating system using a two-way catalyst system.

Detailed Description of the Preferred Embodiments

I. Introduction and definitions.

The present invention relates to methods for upgrading a fluidized bed hydrotreating system to produce low sludge fouling. An upgraded fluidized bed system is created by carrying out the disclosed method.

The term precipitate refers to solids formed in a liquid stream that may settle. The deposits may include inorganic matter, coke, or insoluble asphaltenes that precipitate after conversion.

Sediment in petroleum products is typically measured using the IP-375 Hot Filterability Test Procedure for Total Sediment in Residual Fuel Oil published under ISO 10307 and ASTM D4870. Other tests include the IP-390 sludge test and the Shell hot filtration test. Sediment is associated with oil components that tend to form solids during processing and transportation. These hard forming components have several undesirable effects in the hydroconversion process, including product degradation and serviceability issues associated with equipment fouling. It should be noted that while the strict definition of sludge is based on the measurement of solids in a sludge test, the term is generally used more loosely to refer to the solid forming components of the oil itself, which may not be present as actual solids in the oil, but which contribute to the formation of solids under certain conditions.

Sludge formation can be expressed as an absolute rate of formation (eg, lb/hr or kg/hr) or as a concentration (eg, wt%) in the process stream. Therefore, sludge formation can be determined during initial operation and during operation of a retrofit fluidized bed reactor using a two-way catalyst system of at least one of (i) absolute sludge formation rate or (ii) sludge concentration in at least one process stream . For example, the sediment concentration can be measured in at least one process stream selected from atmospheric residue, atmospheric distillation column bottom residue, vacuum residue, vacuum distillation column bottom residue, atmospheric column feed, hot low pressure separator product, product liquid fuel, VAT residue of the vacuum column after adding distillate oil products.

It should be noted that either the rate of precipitation or the concentration can be changed using a two-way catalyst system, but not necessarily both at the same time, depending on the subtleties of plant operation. For example, when the plant is operated with a significantly higher overall throughput of converted products, the total bottoms after separation (for example, by hot separation, atmospheric distillation and/or vacuum distillation) can be reduced, especially in cases where higher throughput is achieved through the use of higher temperature and conversion at the same throughput. In such a case, the measured sludge concentration in the liquid product or other process stream may be equal to or higher than when operating under initial conditions, even when the absolute sludge formation rate is lower.

The term fouling refers to the formation of an undesirable phase (contaminant) that interferes with processing. The contaminant is typically a carbonaceous material or solid that is deposited and collected in process equipment. Equipment fouling can result in loss of production due to equipment shutdowns, reduced equipment productivity, increased energy consumption due to thermal insulating capacity of contaminant deposits in heat exchangers or heaters, increased maintenance costs to clean equipment, reduced fractionator efficiency, and reduced heterogeneous reactivity. catalyst.

The rate of equipment fouling before and after upgrading a hydrocracking reactor to use a two-way catalyst system can be determined by at least one of: (i) the frequency of heat exchanger cleaning required; (ii) frequency of switching to spare coils; (iii) frequency of filter changes; (iv) frequency of cleaning or replacement of the coarse filter; (v) the rate of decrease in skin temperatures in equipment, including equipment selected from heat exchangers, separators or distillation columns; (vi) the rate of increase in temperature of the chimney metal; (vii) the rate of increase of the calculated fouling thermal resistance factors for heat exchangers and furnaces; (viii) the rate of increase in pressure drop across the heat exchangers; (ix) cleaning frequency of atmospheric and/or vacuum distillation columns; or (x) frequency of major repairs.

The term heavy oil feedstock refers to heavy oil, tar sands, barrel bottoms and bottoms from a conventional process unit (e.g. include a significant amount of asphaltenes, which can deactivate the heterogeneous catalyst and/or cause or lead to the formation of coke precursors and precipitation. Examples of heavy oil feedstocks include, but are not limited to, Lloydminster heavy oil, Cold Lake bitumen, Athabasca bitumen, atmospheric column bottoms, vacuum tower bottoms, bottoms (or tar), bottoms pitch, vacuum bottoms (e.g., Ural VR, Arab Medium VR, Athabasca VR, Cold Lake VR, Maya VR and Chichimene VR), deasphalted fluids obtained by solvent deasphalting, asphaltene fluids obtained as a by-product of deasphalting, and non-volatile liquid fractions that remain after the processing of crude oil, bitumen from oil sands, liquefied coal, oil shale or coal tar raw materials for distillation, hot separation, solvent extraction and the like. For purposes of further example, atmospheric column bottoms (ATB) may have a nominal initial boiling point of at least 343°C (650°F) although it is understood that the cut-off point may vary among refineries and be as high as 380°C (716°F). Vacuum column bottoms can have a nominal initial boiling point of at least 524°C (975°F) although it is understood that the boiling point of fractions can vary among refineries and reach 538°C (1000°F) or even 565°C (1050°F ).

The terms asphaltene and asphaltenes refer to materials in heavy oil feedstocks that are generally insoluble in paraffinic solvents such as propane, butane, pentane, hexane and heptane. Asphaltenes may include layers of condensed ring compounds held together by heteroatoms such as sulfur, nitrogen, oxygen, and metals. Asphaltenes in a broad sense include a variety of complex compounds having from 80 to 1200 carbon atoms with predominant molecular weights, which is established by solution technology in the range of 1200-16900. Approximately 80-90% of the metals in crude oil are contained in the asphaltene fraction, which, together with the higher concentration of non-metallic heteroatoms, makes the asphaltene molecules more hydrophilic and less hydrophobic than other hydrocarbons in crude oil. The proposed asphaltene molecular structure developed by AG Bridge and collaborators at Chevron is shown in FIG. 1. As a rule, asphaltenes are usually determined based on the results of insolubles determination methods, and more than one determination of asphaltenes may be used. In particular, the commonly used definition of asphaltenes is those insoluble in heptane minus those insoluble in toluene (i.e. asphaltenes soluble in toluene, precipitates and residues insoluble in toluene are not considered asphaltenes). Asphaltenes thus defined may be referred to as C ₇ -asphaltenes. However, an alternative definition can also be used with equal certainty, measured as insoluble in pentane minus insoluble in toluene and commonly referred to as C ₅ -asphaltenes.

In the examples of the present invention, the definition of C7 asphaltenes is used, but can easily be changed to the definition of C ₅ asphaltenes.

The quality of a heavy oil can be measured by at least one characteristic selected from, but not limited to: (i) boiling point; (ii) sulfur concentration; (iii) nitrogen concentration; (iv) concentration of metals; (v) molecular weight; (vi) the ratio of hydrogen to carbon; (vii) asphaltene content; and (viii) a tendency to precipitate.

The low quality heavy oil and/or low quality feedstock blend may have at least one low quality characteristic compared to the heavy oil feedstock, selected from, but not limited to: (i) higher boiling point; (ii) higher sulfur concentration; (iii) higher nitrogen concentration; (iv) higher concentration of metals; (v) higher molecular weight (often indicated by higher density and viscosity); (vi) lower hydrogen to carbon ratio; (vii) higher asphaltene content; and (viii) greater tendency to precipitate.

The term advantageous feedstock refers to low quality heavy oils and low quality blends of heavy oil feedstocks having at least one inferior quality characteristic compared to the original heavy oil feedstock. Beneficial feedstocks also tend to have a lower market value (or price) compared to the feedstock.

The terms hydrocracking and hydroconversion refer to a process whose main purpose is to reduce the boiling range of a heavy oil feedstock and in which a significant portion of the feedstock is converted to products with boiling ranges lower than those of the feedstock. Hydrocracking or hydroconversion typically involves the fragmentation of larger hydrocarbon molecules into smaller molecular fragments having fewer carbon atoms and a higher hydrogen to carbon ratio. The mechanism by which hydrocracking occurs typically involves the formation of hydrocarbon free radicals during thermal fragmentation followed by capping of the ends of the free radicals or fragments with hydrogen. Hydrogen atoms or radicals that interact with hydrocarbon free radicals during hydrocracking can be formed at or at active catalytic sites.

The term hydrotreating refers to operations whose main purpose is to remove impurities such as sulfur, nitrogen, oxygen, halides and trace metals from feedstocks and saturate olefins and/or stabilize hydrocarbon free radicals by reacting them with hydrogen instead of allowing them to react together. The main goal is not to change the boiling range of the raw material. Hydrotreating is most commonly carried out using a fixed bed reactor, although other hydrotreating reactors can also be used for hydrotreating, an example of which is the fluidized bed hydrotreating reactor.

Of course, hydrocracking or hydroconversion can also involve the removal of sulfur and nitrogen from feedstocks, as well as olefin saturation and other reactions commonly associated with hydrotreating. The terms hydrotreating and hydroconversion broadly refer to both hydrocracking and hydrotreating processes that define opposite ends of the spectrum and everything within the spectrum.

The term hydrocracking reactor refers to any vessel in which the main purpose is to hydrocrack (ie, reduce the boiling range) of a feedstock in the presence of hydrogen and a hydrocracking catalyst. Hydrocracking reactors are characterized by having an inlet into which heavy oil feed and hydrogen can be introduced, an outlet from which enriched feed or material can be expelled, and sufficient thermal energy to generate hydrocarbon free radicals to cause fragmentation. larger hydrocarbon molecules into smaller molecules. Examples of hydrocracking reactors include, but are not limited to, slurry phase reactors (i.e. two-phase gas-liquid system), fluidized bed reactors (i.e. three-phase gas-liquid-solid system), fixed bed reactors (i.e. a three-phase system that includes a liquid feed dropping down or flowing up through a fixed bed of a solid heterogeneous catalyst with hydrogen, usually flowing cocurrently, but possibly countercurrently, to the heavy oil).

The term hydrocracking temperature refers to the minimum temperature required to effect significant hydrocracking of a heavy oil feedstock. In general, hydrocracking temperatures are preferably in the range from about 399°C (750°F) to about 460°C (860°F), more preferably in the range from about 418°C (785°F) to about 443°C (830 °F) and most preferably in the range from about 421°C (790°F) to about 440°C (825°F).

The term gas-liquid slurry-phase hydrocracking reactor refers to a hydrotreating reactor that includes a continuous liquid phase and a gaseous dispersed phase that forms a suspension of gaseous bubbles in the liquid phase. The liquid phase typically contains hydrocarbon feedstock, which may contain a low concentration of dispersed metal sulfide catalyst particles, and the gaseous phase typically contains hydrogen gas, hydrogen sulfide, and vaporized low-boiling hydrocarbon products. The liquid phase may optionally include

- 6 041150 solvent - hydrogen donor. The term three-phase gas-liquid-solid slurry hydrocracking reactor is used when a solid catalyst is used together with liquid and gas. The gas may contain hydrogen, hydrogen sulfide and evaporated low-boiling hydrocarbon products. The term slurry phase reactor broadly refers to both types of reactors (eg, reactors with dispersed metal sulfide catalyst particles, reactors with micron-sized or larger catalyst particles, and reactors that include both).

The terms solid heterogeneous catalyst, heterogeneous catalyst and supported catalyst refer to catalysts commonly used in fluidized bed and fixed bed hydrotreating systems, including catalysts primarily for hydrocracking, hydroconversion, hydrodemetallization and/or hydrotreating.

A heterogeneous catalyst typically contains: (i) a catalyst support having a large surface area and interconnected channels or pores; and (ii) fine active catalyst particles such as cobalt, nickel, tungsten and molybdenum sulfides dispersed in channels or pores. The pores of the carrier are usually of limited size to maintain the mechanical integrity of the heterogeneous catalyst and to prevent degradation and the formation of excessive fines in the reactor. Heterogeneous catalysts can be obtained in the form of cylindrical pellets, cylindrical extrudates, other shapes such as trefoils, rings, saddles or the like, or spherical solids.

The terms dispersed metal sulfide catalyst particles and dispersed catalyst refer to catalyst particles having a particle size that is less than 1 micron (submicron), such as less than about 500 nm in diameter, or less than about 250 nm in diameter, or less than about 100 nm in diameter, or less than about 50 nm in diameter, or less than about 25 nm in diameter, or less than about 10 nm in diameter, or less than about 5 nm in diameter. The term dispersed metal sulfide catalyst particles may include molecular or molecularly dispersed catalyst compounds. The term dispersed metal sulfide catalyst particles excludes metal sulfide particles and agglomerates of metal sulfide particles that are larger than 1 µm.

The term molecularly dispersed catalyst refers to catalyst compounds that are substantially dissolved or dissociated from other catalyst compounds or molecules in a hydrocarbon feed or a suitable diluent. It may include very small catalyst particles that contain several catalytic molecules linked together (eg, 15 molecules or less).

The terms residual catalyst particles refer to catalyst particles that remain with enriched material when transferred from one vessel to another (eg, from a hydrotreating reactor to a separator and/or another hydrotreating reactor).

The term conditioned feed refers to a hydrocarbon feed in which the catalyst precursor has been combined and mixed so completely that when the catalyst precursor decomposes and forms an active catalyst, the catalyst contains dispersed metal sulfide catalyst particles formed in situ in the feed.

The terms upgrade, upgrade, and upgrade, when used to describe a feedstock that is or has been hydrotreated, or a finished material or product, refer to one or more of feedstock molecular weight reduction, feedstock boiling range reduction, asphaltene reduction, free hydrocarbon concentration reduction. radicals and/or reduction of impurities such as sulfur, nitrogen, oxygen, halides and metals.

The term rate usually refers to the amount of energy that is injected into the heavy oil during hydrotreating and is often related to the operating temperature of the hydrotreating reactor (i.e. higher temperature is associated with higher rate, lower temperature is associated with lower rate) in combination with the duration of the mentioned temperature effect. The increased intensity generally increases the amount of conversion products produced by the hydrotreating reactor, including both desired products and unwanted conversion products. Desirable conversion products include hydrocarbons with reduced molecular weight, boiling point and specific gravity, which may include end products such as naphtha, diesel fuel, jet fuel, kerosene, wax, liquid fuels, and the like. Other desirable conversion products include higher boiling hydrocarbons, which can be further processed using conventional purification and/or distillation techniques. Undesired conversion products include coke, sludge, metals, and other solid materials that can deposit on hydrotreating equipment and cause fouling, such as internal components of reactors, separators, filters, pipes, columns, heat exchangers, and heterogeneous catalyst.

Undesired conversion products may also refer to unreacted residues that remain after distillation, such as atmospheric column bottoms (ATB) or vacuum column bottoms (VTB). Minimizing unwanted conversion products

- 7 041150 removes equipment contamination and equipment shutdowns required to clean equipment. However, there may be a desired amount of unreacted residue in order for the downstream separation equipment to function properly and/or to provide a liquid transport medium for containing coke, sediment, metals and other solids that might otherwise be deposited. on and contaminate equipment if not carried away by remaining residues.

In addition to temperature, intensity may be related to one or both of conversion and throughput. Regardless of whether the increased rate includes increased conversion and/or increased or decreased throughput, it may depend on the quality of the heavy oil feedstock and/or the mass balance of the entire hydrotreating system. For example, when it is desired to convert more feed and/or provide more material to downstream equipment, the increased rate may primarily include increased throughput without the need for increased fractional conversion. This may include the case where the residue fractions (ATB and/or VTB) are sold as liquid fuels and increased conversion without increased throughput may reduce the amount of this product. In the case where it is desired to increase the ratio of enriched materials to residue fractions, it may be desirable to increase the conversion in the first place without the need to increase throughput. When the quality of the heavy oil introduced into the hydrotreating reactor fluctuates, it may be desirable to selectively increase or decrease one or both of the conversion and throughput in order to maintain the desired ratio of enriched materials to residue fractions and/or the desired absolute amount or amounts of final product(s). (s) product(s).

The terms conversion and conversion ratio refer to the ratio, often expressed as a percentage, of heavy oil that is converted to lower boiling and/or lower molecular weight materials. The conversion is expressed as a percentage of the original content of the residue (i.e. components with a boiling point greater than the defined boiling point of the fractions of the residue), which is converted into products with a boiling point less than the specified boiling point of the fractions. The definition of the boiling point of the residue fractions may vary and may nominally include 524°C (975°F), 538°C (1000°F), 565°C (1050°F) and the like. It can be measured by distillation analysis of the feed and product streams to determine the concentration of components with a boiling point greater than the defined boiling point of the fractions. The conversion is expressed as (F-P)/F where F is the amount of residue in the combined feed streams and P is the amount in the combined product streams where the feed and product residue contents are based on the same definition of the boiling point of the fractions. The amount of residue is most often determined based on the mass of components with a boiling point greater than the defined boiling point of the fractions, but volumetric or molar definitions may also be used.

The term throughput refers to the amount of feedstock that is introduced into the hydrotreating reactor as a function of time. Throughput can be expressed in volume units such as barrels per day or in mass terms such as metric tons per hour. In general usage, throughput is defined as the mass or volumetric feed rate of the heavy oil feed itself only (eg vacuum column bottoms or the like). The definition generally does not include amounts of diluents or other components that may sometimes be included in the total hydroconversion feedstock, although a definition that includes these other components may also be used.

The rate of production of converted products is an absolute rate, which can be expressed in volume units such as barrels per day or in mass terms such as metric tons per hour. The rate of production of converted products should not be confused with output or efficiency, which is sometimes erroneously referred to as rate (for example, rate of production per unit feed rate or rate of production per unit of raw material converted). It should be appreciated that the actual numerical values of both the initial rate of converted products and the increased rate of converted products are specific to an individual production facility and depend on the capacity of that facility. Therefore, it is fair to compare the performance of an installation or facility in question before and after the upgrade, but not in comparison with another installation or facility built with a different capacity.

II. Fluidized bed hydrotreating systems and reactors.

In FIG. 2A-2D schematically depict non-limiting examples of fluidized bed hydrotreatment systems and reactors used to hydrotreat hydrocarbon feedstocks such as heavy oils that can be upgraded with a two-way catalyst system in accordance with the invention. It should be understood that exemplary fluidized bed hydrotreating systems and reactors may include intermediate separation, integrated hydrotreating, and/or integrated hydrocracking.

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In FIG. 2A schematically illustrates a fluidized bed hydrotreating reactor 10 used in the LC-Fining hydrocracking system developed by C-E Lummus. The fluidized bed reactor 10 includes an inlet 12 near the bottom through which feedstock 14 and pressurized hydrogen gas 16 are introduced and an outlet 18 at the top through which hydrotreated material is removed.

20.

The reactor 10 further includes a loosened catalyst zone 22 containing a heterogeneous catalyst 24 that is maintained in a loosened or fluidized state against gravity by the upward movement of liquid hydrocarbons and gas (schematically depicted as bubbles 25) through the fluidized bed reactor 10. the end of the loosened catalyst zone 22 is bounded by a distribution grid 26, which separates the loosened catalyst zone 22 from the lower heterogeneous catalyst-free zone 28 located between the bottom of the fluidized bed reactor 10 and the distribution grid 26. The distribution grid 26 is configured to evenly distribute the gaseous hydrogen and hydrocarbons through the reactor and prevents the heterogeneous catalyst 24 from falling by gravity into the lower zone 28 free from the heterogeneous catalyst. The upper end of the loosened catalyst zone 22 is the height at which downward gravity begins to equal or exceed the hydrostatic lift of the upwardly moving feed and gas through the fluidized bed reactor 10 while the heterogeneous catalyst 24 reaches a desired level of loosening or separation. Above the loosened catalyst zone 22 is an upper zone 30 free of heterogeneous catalyst.

Hydrocarbons and other materials in the fluidized bed reactor 10 are continuously recycled from the upper heterogeneous catalyst free zone 30 to the lower heterogeneous catalyst free zone 28 via a recycle channel 32 located in the center of the fluidized bed reactor 10 connected to an ebullation pump 34 at the bottom. fluidized bed reactor 10. In the upper part of the recirculation channel 32 is a funnel-shaped recirculation bowl 36, through which feed is fed from the upper zone 30 free of heterogeneous catalyst. The material transported down through the recirculation channel 32 enters the lower catalyst-free zone 28 and then passes upward through the distribution grid 26 and into the loosened catalyst zone 22, where it mixes with freshly added feed 14 and hydrogen gas 16 entering the reactor fluidized bed 10 through inlet 12. Continuous circulation of mixed materials upwards through fluidized bed reactor 10 advantageously maintains heterogeneous catalyst 24 in a loosened or fluidized state in the loosened catalyst zone 22, minimizes channeling, controls reaction rates, and conserves heat generated by exothermic reactions. hydrogenation to a safe level.

Fresh heterogeneous catalyst 24 is introduced into the fluidized bed reactor 10, for example, into the loosened catalyst zone 22, through the catalyst inlet pipe 38, which passes through the top of the fluidized bed reactor 10 and directly into the loosened catalyst zone 22. The spent heterogeneous catalyst 24 is withdrawn from the zone of the loosened catalyst 22 through the catalyst withdrawal pipe 40, which extends from the lower end of the loosened catalyst zone 22 through the distribution grid 26 and the bottom of the fluidized bed reactor 10. , but the active catalyst is from the freshly added catalyst, so that the uneven distribution of the heterogeneous catalyst 24 is usually withdrawn from the fluidized bed reactor 10 as a spent catalyst.

The enriched material 20 withdrawn from the fluidized bed reactor 10 may be introduced into a separator 42 (eg, a hot separator, an intermediate pressure swing separator, or a distillation column, eg, atmospheric or vacuum). Separator 42 separates one or more volatile fractions 46 from non-volatile fraction 48.

In FIG. 2B schematically illustrates a fluidized bed reactor 110 used in an H-Oil hydrocracking system developed by Hydrocarbon Research Incorporated and currently licensed by Axens. The fluidized bed reactor 110 includes an inlet 112 through which heavy oil feedstock 114 and pressurized hydrogen gas 116 are introduced, and an outlet 118 through which enriched material 120 is withdrawn. bounded by a distribution grid 126 which separates the loose catalyst zone 122 from the lower catalyst free zone 128, between the bottom of the reactor 110 and the distribution grid 126 and an upper end 129 which defines the approximate boundary between the loose catalyst zone 122 and the upper catalyst free zone 130 . The dotted boundary 131 schematically depicts the approximate level of heterogeneous catalyst 124 when it is not in the loosened or fluidized state.

Materials are continuously recirculated in the reactor 110 via a recirculation channel 132 connected to an ebullation pump 134 located outside the reactor 110. Materials

- 9 041150 are transported through the funnel-shaped bowl 136 from the upper zone 130, free of catalyst.

The 136 recirculation bowl is spiral-shaped to help separate hydrogen bubbles

125 from the recirculating material 132 to prevent cavitation of the ebullation pump 134.

The recycle material 132 enters the lower catalyst free zone 128 where it mixes with fresh feed 116 and hydrogen gas 118 and the mixture passes through the distribution grid 126 and into the loose catalyst zone 122. The fresh catalyst 124 is introduced into the loose catalyst zone 122 through the inlet catalyst pipe 136, and the spent catalyst 124 is removed from the loose catalyst zone 122 through the catalyst withdrawal pipe 140.

The main difference between the H-Oil 110 fluidized bed reactor and the LCFining 10 fluidized bed reactor is the location of the ebullation pump. The ebullation pump 134 in the H-Oil reactor 110 is located outside the reaction chamber. The recycle feed is introduced through a recycle channel 141 at the bottom of the reactor 110. The recycle channel 141 includes a distributor 143 that promotes uniform distribution of the materials through the lower catalyst-free zone 128. It is shown that enriched material 120 is sent to separator 142 which separates one or more volatile fractions 146 from non-volatile fraction 148.

In FIG. 2C schematically illustrates a fluidized bed hydrotreating system 200 comprising multiple fluidized bed reactors. The hydrotreating system 200, exemplified by the LC-Fining hydrotreater, may include three fluidized bed reactors 210 arranged in series to upgrade feedstock 214. Feedstock 214 is introduced into first fluidized bed reactor 210a along with hydrogen gas 216, both of which pass through appropriate heaters before entering the reactor. The enriched material 220a from the first fluidized bed reactor 210a is introduced along with additional hydrogen gas 216 into the second fluidized bed reactor 210b. The enriched material 220b from the second fluidized bed reactor 210b is introduced along with additional hydrogen gas 216 into the third fluidized bed reactor 210c.

It should be understood that one or more intermediate separators may optionally be placed between the first and second reactors 210a, 210b and/or the second and third reactors 210b, 210c to remove lower 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 hexanes and heptanes, which are valuable fuel products but poor solvents for asphaltenes. The removal of volatile materials between multiple reactors increases the production of valuable products and increases the solubility of asphaltenes in the hydrocarbon liquid fraction fed to the downstream reactor(s). Both increase the efficiency of the entire hydrotreating system.

The enriched material 220c from the third fluidized bed reactor 210c is sent to a high temperature separator 242a which separates volatile and non-volatile fractions. The volatile fraction 246a passes through a heat exchanger 250 which preheats the hydrogen gas 216 before being introduced into the first fluidized bed reactor 210a. The slightly cooled volatile fraction 246a is sent to a medium temperature separator 242b, which separates the remaining volatile fraction 246b from the resulting liquid fraction 248b, which is formed as a result of cooling by the heat exchanger 250. The remaining volatile fraction 246b is sent downstream to the low temperature separator 246c for further separation into gas fraction 252c; and degassed liquid fraction 248c.

The liquid fraction 248a from the high temperature separator 242a is sent along with the produced liquid fraction 248b from the medium temperature separator 242b to the low pressure separator 242d, which separates the hydrogen-rich gas 252d from the degassed liquid fraction 248d, which is then mixed with the degassed liquid fraction 248c from the low temperature separator 242c and fractionated into products. The gaseous fraction 252c from the low temperature separator 242c is scrubbed into off gas, purge gas, and hydrogen gas 216. Hydrogen gas 216 is compressed, mixed with make-up hydrogen gas 216a, and passed through heat exchanger 250 and introduced into first fluidized bed reactor 210a along with feed 216 or injected directly into the second and third fluidized bed reactors 210b and 210c.

In FIG. 2D schematically illustrates a fluidized bed hydrotreating system 200 comprising multiple fluidized bed reactors, similar to the system illustrated in FIG. 2C, but showing an intermediate separator 221 located between the second and third reactors 210b, 210c (although the intermediate separator 221 may be located between the first and second stage reactors 210a, 210b). As shown, the effluent from the second stage reactor 210b enters an intermediate separator 221, which may be a high pressure high temperature separator. The liquid fraction from separator 221 is combined with a portion of the hydrogen recycle from line 216 and then sent to third stage reactor 210c. The vapor fraction from the intermediate separator 221 bypasses the third stage reactor 210c, mixes with the effluent from the third stage reactor 210c and then enters the high temperature separator 242a.

- 10 041150

This allows the lighter, richer components formed in the first two stage reactors to bypass the third stage reactor 210c. The advantages of this are: (1) reduced steam load on the third stage reactor, which increases the volumetric utilization of the third stage reactor for converting the remaining heavy components, and (2) reduced concentration of anti-solvent components (saturated hydrocarbons) that can destabilize asphaltenes in the third stage reactor 210c.

In preferred embodiments, hydrotreating systems are designed and operated to promote hydrocracking reactions, as compared to hydrotreating, which is a less severe form of hydrotreating. Hydrocracking involves the breaking of carbon-carbon molecular bonds, and in particular the reduction in molecular weight of larger hydrocarbon molecules and/or ring opening of aromatic compounds. On the other hand, hydrotreating mainly involves the hydrogenation of unsaturated hydrocarbons with minimal or no destruction of carbon-carbon molecular bonds. To promote hydrocracking rather than just hydrotreatment reactions, the hydrotreating reactor(s) are 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) are preferably operated at pressures ranging from about 1000 psi (6.9 MPa) to about 3000 psi (20.7 MPa), more preferably in the range from about 1500 psi (10.3 MPa) to about 2500 psi (17.2 MPa), and are preferably operated at a space velocity (e.g., liquid hourly space velocity or LHSV, defined as the ratio of volume delivered to the volume of the reactor per hour) in the range from about 0.05 h ^-1 to about 0.45 h' ¹ , more preferably in the range from about 0.15 h ^-1 to about 0.35 h' ¹ . The difference between hydrocracking and hydrotreating can also be expressed in terms of residue conversion (where hydrocracking results in a significant conversion of higher boiling to lower boiling hydrocarbons, whereas this does not occur in hydrotreating). The hydrotreating systems disclosed herein can result in residue conversions ranging from about 40% to about 90%, preferably in the range from about 55% to about 80%. The preferred conversion range generally depends on the type of feedstock due to differences in processing complexity among different feedstocks. Typically, the conversion will be at least 5% higher, preferably at least 10% higher, compared to operating a fluidized bed reactor prior to upgrading with a two-way catalyst system as disclosed herein.

III. Upgraded fluidized bed hydrotreating reactor.

In FIG. 3A, 3B, 3C, and 3D are flow charts that illustrate exemplary methods for upgrading a fluidized bed reactor using a two-way catalyst system and achieving low sludge fouling.

In FIG. 3A more specifically illustrates a process comprising: (A) an initially operating fluidized bed reactor using a heterogeneous catalyst for hydrotreating heavy oil under initial conditions and sludge formation and promoting fouling at a given rate; (B) adding or forming in situ dispersed metal sulfide catalyst particles into the fluidized bed reactor to form an upgraded reactor with a two-way catalyst system; and (C) operating the upgraded fluidized bed reactor using a two-way catalyst system producing little sediment fouling than the initial operation of the fluidized bed reactor.

In accordance with some embodiments, the heterogeneous catalyst used in the initial operation of the fluidized bed reactor in the initial state is a commercially available catalyst commonly used in fluidized bed reactor systems. To maximize efficiency, the initial conditions of the reactor are preferably at a level at which sludge formation and equipment fouling are maintained at acceptable levels. Increased fouling (absolute fouling rate and/or increased wt % fouling in at least one process stream) without retrofitting the fluidized bed reactor with a two-way catalyst system can therefore lead to increased equipment fouling that would otherwise require more frequent shutdowns and cleaning of the hydrotreating reactor and related equipment such as pipes, columns, heaters, heat exchangers, heterogeneous catalyst and/or separation equipment.

To produce negligible sludge contamination, for example by increasing the rate of converted products and/or the rate of sludge formation and/or the concentration of sludge in at least one process stream (for example, by increasing the reactor intensity and/or the rate of converted products) without increasing the contamination equipment and the need for more frequent shutdowns and maintenance, the fluidized bed reactor is upgraded with a two-way catalyst system containing a heterogeneous catalyst and dispersed metal sulfide catalyst particles. Operation of an upgraded fluidized bed reactor with negligible sludge fouling may include the operation of

- 11 041150 a solution with higher conversion and/or higher throughput than when operating under initial conditions. Also typically include operating the upgraded reactor at elevated temperatures and increasing sludge formation and equipment fouling rates. However, obtaining negligible sludge fouling results in less equipment fouling and reduced frequency of shutdowns and purges when sludge forms at a given rate or wt % in the process stream.

In one embodiment, a method for upgrading a fluidized bed hydrotreating system that includes one or more fluidized bed reactors to produce negligible sludge fouling comprises: (1) operating a fluidized bed reactor using a heterogeneous heavy oil hydrotreating catalyst under initial conditions, including initial throughput of converted products, initial sedimentation rate and/or concentration in the process stream, and initial equipment fouling rate; (2) then upgrading the fluidized bed reactor to operate with a two-way catalyst system consisting of dispersed metal sulfide catalyst particles and a heterogeneous catalyst; and (3) operating an upgraded fluidized bed reactor using a two-way catalyst system with little sludge fouling resulting in less equipment fouling at a given sludge rate and/or concentration compared to operating the fluidized bed reactor under initial conditions.

In one embodiment, operating an upgraded fluidized bed reactor using a two-way catalyst system to produce negligible sludge fouling comprises: (i) producing converted products at the same or similar rate as the initial production of converted products when operating under initial conditions; (ii) producing a sludge at a reduced rate and/or concentration in the process stream compared to the initial sludge rate and/or concentration during initial operation; and (iii) the fouling of the equipment occurs at a reduced rate compared to the initial fouling rate of the equipment during initial operation and where the fouling rate of the equipment is reduced to a greater extent than the reduction in sedimentation rate and/or concentration.

In another embodiment, operating an upgraded fluidized bed reactor using a two-way catalyst system to produce negligible sludge fouling comprises: (i) producing converted products at a higher rate than the initial production of converted products during initial operation; (ii) obtaining a sludge at a rate and/or concentration in the process stream that does not exceed the initial sludge rate and/or concentration during initial operation; and (iii) equipment fouling occurs at a reduced rate compared to the initial equipment fouling rate during initial operation.

In yet another embodiment, operating an upgraded fluidized bed reactor using a two-way catalyst system to produce negligible sludge fouling comprises: (i) producing converted products at a higher rate than the initial production of converted products during initial operation; (ii) obtaining a precipitate at a higher rate and/or concentration than the initial rate of precipitation and/or concentration during initial operation; and (iii) equipment fouling occurs at a rate that does not exceed the initial fouling rate of the equipment during initial operation.

In one embodiment, the productivity of converted products is increased by operating the upgraded fluidized bed reactor using a two-way catalyst system of at least one of: (i) higher temperature and higher conversion at the same or similar throughput compared to operating under initial conditions ; (ii) higher temperature and higher throughput at the same or similar conversion compared to initial operation; or (iii) higher temperature, higher throughput and higher conversion compared to initial operation. In some embodiments, the throughput can be increased by at least 2.5%, at least 5%, at least 10%, or at least 20% when operating the upgraded fluidized bed reactor compared to operating in initial conditions. In some embodiments, the conversion can be increased by at least 2.5%, at least 5%, at least 7.5%, at least 10%, or at least 15% by operating the upgraded reactor. with a fluidized bed compared to operation in the initial conditions. In some embodiments, the temperature may be increased by at least 2.5°C, at least 5°C, at least 7.5°C, or at least 10°C when operating the upgraded fluidized bed reactor. compared to operation under initial conditions.

In some embodiments, after upgrading a fluidized bed reactor using

- 12 041150 by using a two-way catalyst system, the sludge formation rate and/or concentration in the process stream is maintained or increased compared to the initial sludge formation rate and/or concentration, and the equipment fouling rate is reduced by at least 5%, 25%, 50%, or 75% by compared to the initial contamination rate of the equipment. In some embodiments, after upgrading to a two-way catalyst system, the fouling rate is increased by at least 2%, 10%, 20%, or 33% from the initial fouling rate, and the equipment fouling rate is maintained or reduced from the initial fouling rate of the equipment. In some embodiments, after upgrading to a two-way catalyst system, the sludge concentration in the process stream is increased by at least 2%, 10%, 20%, or 33% from the initial sludge concentration and the equipment fouling rate is maintained or reduced from the initial equipment fouling rate. . In some embodiments, after upgrading to a two-way catalyst system, the fouling rate is reduced by at least 2%, 10%, 30%, or 50% of the initial fouling rate, and the equipment fouling rate is reduced by an even greater percentage of the original fouling rate. equipment. In some embodiments, after upgrading to a two-way catalyst system, the sludge concentration in the process stream is reduced by at least 2%, 10%, 30%, or 50% from the initial sludge concentration, and the equipment fouling rate is reduced by an even greater percentage from the initial rate. equipment contamination.

In FIG. 3B is a flow diagram illustrating an exemplary fluidized bed reactor upgrade to reduce equipment fouling rather than reduce sludge formation, which is an embodiment of the method illustrated in FIG. 3A. In FIG. 3B more specifically illustrates a process comprising: (A) an initially operating fluidized bed reactor using a heterogeneous catalyst to hydrotreat heavy oil under initial conditions to form a precipitate at a given rate or concentration in the process stream and promote equipment fouling at a given rate; (B) adding or forming in situ dispersed metal sulfide catalyst particles into the fluidized bed reactor to form an upgraded reactor with a two-way catalyst system; and (C) operating an upgraded fluidized bed reactor using a two-way catalyst system to reduce the fouling rate and/or concentration and reduce the fouling rate of the equipment by a percentage greater than the percentage reduction in fouling rate or concentration.

In one embodiment, a method for upgrading a fluidized bed hydrotreating system that includes one or more fluidized bed reactors to produce negligible sludge fouling comprises: (1) operating a fluidized bed reactor using a heterogeneous heavy oil hydrotreating catalyst under initial conditions, including initial sedimentation rate and/or concentration in the process stream and initial equipment fouling rate; (2) then upgrading the fluidized bed reactor to operate with a two-way catalyst system consisting of dispersed metal sulfide catalyst particles and a heterogeneous catalyst; and (3) operating an upgraded fluidized bed reactor using a two-way catalyst system with a reduced fouling rate and/or concentration and a reduced fouling rate of equipment with a reduction rate that is greater than the fouling rate and/or concentration reduction. In some embodiments, operating an upgraded fluidized bed reactor includes reducing the sludge rate and/or concentration in the process stream by at least 2%, 10%, 30%, or 50% compared to the initial sludge rate and/or concentration and reducing the rate equipment contamination by at least 5%, 25%, 50%, or 75% of the initial equipment contamination rate.

In FIG. 3C is a flow diagram illustrating an exemplary fluidized bed reactor upgrade to reduce equipment fouling with similar sludge formation, which is an embodiment of the method illustrated in FIG. 3A. In FIG. 3C more specifically illustrates a process comprising: (A) an initially operating fluidized bed reactor using a heterogeneous catalyst to hydrotreat heavy oil under initial conditions to produce a precipitate at a given rate and/or concentration in the process stream and promote equipment fouling at a given rate; (B) adding or forming in situ dispersed metal sulfide catalyst particles in a fluidized bed reactor to form an upgraded reactor with a two-way catalyst system; and (C) operating the upgraded fluidized bed reactor using a two-way catalyst system at the same or similar sludge rate and/or concentration and lower equipment fouling rate.

In one embodiment, a method for upgrading a fluidized bed hydrotreating system,

- 13 041150 which includes one or more fluidized bed reactors with low sludge fouling, comprises: (1) operating a fluidized bed reactor using a heterogeneous heavy oil hydrotreating catalyst under initial conditions, including initial sludge formation rate and/or concentration in the process flow and the initial rate of contamination of the equipment; (2) then upgrading the fluidized bed reactor to operate with a two-way catalyst system consisting of dispersed metal sulfide catalyst particles and a heterogeneous catalyst; and (3) operating the upgraded fluidized bed reactor using a two-way catalyst system at the same or similar deposit formation rate and/or concentration and at a reduced equipment fouling rate. In some embodiments, operating the upgraded fluidized bed reactor includes reducing the equipment fouling rate by at least 5%, 25%, 50%, or 75% of the equipment's initial fouling rate.

In FIG. 3D is a flow diagram illustrating an exemplary method for upgrading a fluidized bed reactor to increase sludge generation without increasing equipment fouling rate, which is an embodiment of the method illustrated in FIG. 3A. In FIG. 3D more specifically illustrates a process comprising: (A) an initially operating fluidized bed reactor using a heterogeneous catalyst to hydrotreat heavy oil under initial conditions to produce a precipitate at a given rate and/or concentration in the process stream and promote equipment fouling at a given rate; (B) adding or forming in situ dispersed metal sulfide catalyst particles in a fluidized bed reactor to form an upgraded reactor with a two-way catalyst system; and (C) operating the upgraded fluidized bed reactor using a two-way catalyst system at a higher sludge rate and/or concentration and without reducing the equipment fouling rate.

In one embodiment, a method for upgrading a fluidized bed hydrotreating system that includes one or more fluidized bed reactors to produce negligible sludge fouling comprises: (1) operating a fluidized bed reactor using a heterogeneous heavy oil hydrotreating catalyst under initial conditions, including initial sedimentation rate and/or concentration in the process stream and initial equipment fouling rate; (2) then upgrading the fluidized bed reactor to operate with a two-way catalyst system consisting of dispersed metal sulfide catalyst particles and a heterogeneous catalyst; and (3) operating the upgraded fluidized bed reactor using a two-way catalyst system at a higher sludge rate and/or concentration and at the same or lower equipment fouling rate. In some embodiments, operating the upgraded fluidized bed reactor includes increasing the sludge rate and/or sludge concentration in the process stream by at least 2%, 10%, 20%, or 33% over the initial sludge rate and/or concentration.

The dispersed metal sulfide catalyst particles can be prepared separately and then added to a fluidized bed reactor to form a two-way catalyst system. Alternatively, or in addition, at least a portion of the dispersed metal sulfide catalyst particles may be produced in situ within a fluidized bed reactor.

In some embodiments, the dispersed metal sulfide catalyst particles are predominantly formed in situ within the bulk of the heavy oil feedstock. This can be achieved by first mixing the catalyst precursor with the entire volume of the heavy oil feedstock to form a conditioned feedstock and then heating the conditioned feedstock to decompose the catalyst precursor, and allowing or assisting the catalytic metal to react with the sulfur and/or sulfur containing molecules in the heavy oil and/or added to heavy oil with the formation of dispersed particles of the metal sulfide catalyst.

The catalyst precursor may be oil-soluble and have a decomposition temperature in the range from about 100°C (212°F) to about 350°C (662°F) or in the range from about 150°C (302°F) to about 300°C ( 572°F) or in the range from about 175°C (347°F) to about 250°C (482°F). Examples of catalyst precursors include organometallic complexes or compounds, more particularly oil-soluble compounds or complexes of transition metals and organic acids, having a decomposition temperature or range high enough to avoid significant decomposition when agitated with a heavy oil feedstock under suitable agitation conditions. When mixing the catalyst precursor with the petroleum diluent, it is advantageous to maintain the diluent at a temperature below which significant decomposition of the catalyst precursor occurs. One skilled in the art can, in accordance with the present invention, select a mixing temperature profile that results in thorough mixing of the selected precursor composition without significant decomposition to form dispersed metal sulfide catalyst particles.

- 14 041150

Examples of catalyst precursors include, but are not limited to, molybdenum 2-ethylhexanoate, molybdenum octoate, molybdenum naphthanate, vanadium naphthanate, vanadium octoate, molybdenum hexacarbonyl, vanadium hexacarbonyl, and iron pentacarbonyl. Other catalyst precursors include molybdenum salts containing some cationic molybdenum atoms and some carboxylate anions of at least 8 carbon atoms and which are at least one of (a) aromatic, (b) alicyclic or (c) branched unsaturated and aliphatic. By way of example, each carboxylate anion may have 8 to 17 carbon atoms, or 11 to 15 carbon atoms. Examples of carboxylate anions that fall into at least one of the above 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-phenylvaleric acid, geranic acid (3,7-dimethyl-2,6-octadienoic acid), and combinations thereof.

In other embodiments, carboxylate anions for use in the preparation of oil-soluble thermally stable molybdenum compound catalyst precursors are derived from carboxylic acids selected from the group consisting of 3-cyclopentylpropionic acid, cyclohexanebutyric acid, biphenyl-2-carboxylic acid, 4-heptylbenzoic acid, 5phenylvaleric acid, geranic acid (3,7-dimethyl-2,6-octadienoic acid), 10undecenoic acid, dodecanoic acid, and combinations thereof. Molybdenum catalyst precursors made using carboxylate anions derived from the above carboxylic acids have been found to have improved thermal stability.

Higher thermal stability catalyst precursors may have a first decomposition temperature greater than 210°C, greater than about 225°C, greater than about 230°C, greater than about 240°C, greater than about 275°C, or greater than about 290°C. Such catalyst precursors may have a decomposition temperature limit greater than 250°C, or greater than about 260°C, or greater than about 270°C, or greater than about 280°C, or greater than about 290°C, or greater than about 330°C.

One skilled in the art can, in accordance with the present invention, select a mixing temperature profile that results in thorough mixing of the selected precursor composition without significant decomposition to form dispersed metal sulfide catalyst particles.

Although it is within the scope of the present invention to directly blend the catalyst precursor composition with the heavy oil feedstock, in such cases care must be taken to mix the components for a time sufficient to thoroughly mix the precursor composition in the feedstock before significant degradation of the composition has occurred. predecessor. For example, US Pat. No. 5,578,197 to Cyr et al., the disclosure of which is incorporated by reference, describes a process whereby molybdenum 2-ethylhexanoate was mixed with the bottoms of vacuum column bitumen for 24 hours before the resulting mixture was heated in a reaction vessel. to form a catalytic compound and to carry out hydrocracking (see column 10, lines 4-43). While 24-hour mixing under test conditions may be entirely acceptable, such long mixing times make some commercial operations prohibitively expensive. To ensure thorough mixing of the catalyst precursor in the heavy oil prior to heating to form the active catalyst, several mixing steps are carried out with various mixing devices prior to heating the conditioned feedstock. These may include one or more low shear inline mixers followed by one or more high shear mixers followed by a buffer tank and circulation system followed by one or more high pressure multistage pumps used to maintain feed pressure. stream before introducing it into the hydrotreating reactor.

In some embodiments, the conditioned feedstock is preheated using a heater prior to entering the hydrotreating reactor to form at least a portion of the dispersed metal sulfide catalyst particles in situ in the heavy oil. In other embodiments, the conditioned feedstock is heated or further heated in a hydrotreating reactor to form at least a portion of the dispersed metal sulfide catalyst particles in situ in the heavy oil.

In some embodiments, the dispersed metal sulfide catalyst particles may be formed in a multi-stage process. For example, an oil soluble catalyst precursor composition may be premixed with a hydrocarbon diluent to form a diluted precursor mixture. Examples of suitable hydrocarbon diluents include, but are not limited to, vacuum gas oil (which typically has a nominal boiling range of 360-524°C) (680-975°F), emulsion oil (decantate), or cycle oil (which typically , have a nominal boiling range of 360-550°C) (680-1022°F) and gas oil (which typically has a nominal boiling range of 200-360°C) (392-680°F), some heavy oil feedstocks and others hydrocarbons that nominally boil at temperatures above about 200°C.

- 15 041150

The ratio of catalyst precursor to liquid petroleum diluent used to form the diluted precursor mixture may be in the range of about 1:500 to about 1:1, or in the range of about 1:150 to about 1:2, or in the range of about 1 :100 to about 1:5 (eg 1:100, 1:50, 1:30 or 1:10).

The amount of catalytic metal (eg, molybdenum) in the dilute precursor mixture is preferably in the range from about 100 ppm to about 100 ppm. up to about 7000 ppm by weight of the diluted precursor mixture, more preferably in the range of from about 300 ppm. up to about 4000 ppm by weight of the diluted precursor mixture.

The catalyst precursor is preferably mixed with the hydrocarbon diluent below a temperature at which a significant portion of the catalyst precursor composition decomposes. Mixing can be carried out at a temperature in the range from about 25°C (77°F) to about 250°C (482°F) or in the range from about 50°C (122°F) to about 200°C (392°F ), or in the range from about 75°C (167°F) to about 150°C (302°F) to form a dilute precursor mixture. The temperature at which the diluted precursor mixture is formed may depend on the decomposition temperature and/or other characteristics of the catalyst precursor being used and/or the characteristics of the hydrocarbon diluent such as viscosity.

The catalyst precursor is preferably mixed with the petroleum liquid diluent for a period of time ranging from about 0.1 seconds to about 5 minutes, or from about 0.5 seconds to about 3 minutes, or from about 1 second to 1 minute. The actual mixing time depends at least slightly on temperature (ie, which affects the viscosity of the fluids) and mixing intensity. The mixing intensity depends, at least in part, on the number of stages, for example for an inline static mixer.

Premixing the catalyst precursor with the hydrocarbon diluent to form a dilute precursor mixture, which is then mixed with the heavy oil feedstock, greatly aids in thorough and thorough mixing of the catalyst precursor in the feedstock, especially in the relatively short time required for large scale commercial operation. Formation of a dilute precursor mixture reduces overall mixing time by (1) reducing or eliminating differences in solubility between the more polar catalyst precursor and the more hydrophobic heavy oil feed, (2) reducing or eliminating differences in rheology between the catalyst precursor and the heavy oil feed, and/or ( 3) destruction of the catalyst precursor molecules to form a solute in the hydrocarbon diluent, which is most easily dispersed in the heavy oil feedstock.

The dilute precursor mixture is then combined with the heavy oil feed and mixed for a time sufficient to disperse the catalyst precursor throughout the feed to form a conditioned feed in which the catalyst precursor is intimately mixed in the heavy oil until thermally decomposed and active metal sulfide catalyst particles are formed. . In order to obtain sufficient mixing of the catalyst precursor in the heavy oil feed, the dilute mixture of the precursor and the heavy oil feed is preferably mixed for a period of time in the range of from about 0.1 seconds to about 5 minutes, or in the range from about 0.5 seconds to about 3 minutes, or in the range of from about 1 second to about 3 minutes. Increasing the intensity and/or shear energy of the agitation process will generally reduce the time required to effect intensive agitation.

Examples of a mixing device that can be used to effect intensive mixing of the catalyst precursor and/or a dilute heavy oil precursor mixture include, but are not limited to, high shear mixing, such as mixing created in a vessel with a propeller agitator or a turbine wheel. ; several static built-in mixers; several static inline mixers in combination with high shear inline mixers; several static inline mixers in combination with high shear inline mixers followed by a buffer tank; combinations of the above followed by one or more multistage centrifugal pumps; and one or more multistage centrifugal pumps. In some embodiments, continuous rather than batch mixing can be accomplished using high energy pumps having multiple chambers in which the composition of catalyst precursor and heavy oil feedstock is agitated and agitated as part of the pumping process itself. The aforementioned mixing apparatus can also be used for the premixing process discussed above, in which the catalyst precursor is mixed with a hydrocarbon diluent to form a catalyst precursor mixture.

In the case of a heavy oil feedstock that is hard or extremely viscous at room temperature, such feedstock may advantageously be heated to soften it and create a feedstock having a low enough viscosity to allow good mixing of the oil-soluble catalyst precursor in the composition. raw materials. In general, reducing the viscosity of the heavy oil feedstock will shorten the time required to thoroughly and thoroughly mix the oil soluble catalyst precursor composition in the feedstock.

The heavy oil feedstock and catalyst precursor and/or diluted precursor mixture are advantageously mixed at a temperature in the range of about 25°C (77°F) to about 350°C (662°F) or in the range of about 50°C (122°F ) to about 300°C (572°F) or in the range from about 75°C (167°F) to about 250°C (482°F) to obtain a conditioned feed.

In the case where the catalyst precursor is mixed directly with the heavy oil feedstock without first forming a dilute precursor mixture, it may be advantageous to mix the catalyst precursor and the heavy oil feedstock below a temperature at which a significant portion of the catalyst precursor composition decomposes. However, in the case where the catalyst precursor is premixed with a hydrocarbon diluent to form a dilute precursor mixture which is then mixed with the heavy oil feedstock, it may be acceptable for the heavy oil feedstock to be at or above the decomposition temperature of the catalyst precursor. This is due to the fact that the hydrocarbon diluent screens individual catalyst precursor molecules and prevents their agglomeration with the formation of larger particles, temporarily isolates the catalyst precursor molecules from the heat of heavy oil during mixing, and facilitates the dispersion of catalyst precursor molecules fairly quickly throughout the entire volume of heavy oil feedstock up to decomposition with the release of metal. In addition, additional heating of the feedstock may be necessary to release hydrogen sulfide from the sulfur-containing molecules in the heavy oil to form metal sulfide catalyst particles. Thus, gradual dilution of the catalyst precursor allows a high level of dispersion to be obtained in the heavy oil feed, resulting in the formation of highly dispersed metal sulfide catalyst particles, even if the feed is at a temperature above the decomposition temperature of the catalyst precursor.

After the catalyst precursor has been well mixed throughout the heavy oil to form a conditioned feedstock, the composition is then heated to cause the catalyst precursor to decompose to release the catalytic metal from it, promote or allow it to react with the sulfur within the heavy oil and/or added to the heavy oil, and form active particles of the metal sulfide catalyst. The metal from the catalyst precursor may initially form a metal oxide, which then reacts with the sulfur in the heavy oil to form a metal sulfide compound that forms the finished active catalyst. In the event that the heavy oil feedstock contains sufficient or excess sulfur, the finished activated catalyst may be formed in situ by heating the heavy oil feedstock to a temperature sufficient to release sulfur therefrom. In some cases, sulfur may be released at the same temperature at which the precursor composition decomposes. In other cases, additional heating to a higher temperature may be required.

If the catalyst precursor is thoroughly mixed throughout the heavy oil, at least a significant portion of the released metal ions will be sufficiently protected or shielded from other metal ions so that they can form a molecularly dispersed catalyst when reacted with sulfur to form a metal sulfide compound. In some cases, slight agglomeration may occur resulting in the formation of colloidal sized catalyst particles. However, it is believed that by thoroughly mixing the catalyst precursor throughout the feed prior to thermal decomposition of the catalyst precursor, individual catalyst molecules, rather than colloidal particles, can be obtained. Simply mixing, though not sufficiently mixing, the catalyst precursor with the feedstock typically causes the formation of large agglomerated metal sulfide compounds that are micron in size or larger.

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 from about 330°C (626°F) to about 410°C (770°F).

The initial concentration of catalytic metal provided by the dispersed metal sulfide catalyst particles may range from about 1 ppm to about 1 ppm. up to about 500 ppm by weight of the heavy oil feedstock, or in the range of about 5 ppm. up to about 300 ppm, or in the range from about 10 ppm. up to about 100 ppm The catalyst may become more concentrated as the volatile fractions are removed from the residue fraction.

In the case where the heavy oil feedstock contains a significant amount of asphaltene molecules, the dispersed metal sulfide catalyst particles may preferentially associate with or remain in close proximity to the asphaltene molecules. Asphaltene molecules may have a greater affinity for metal sulfide catalyst particles because asphaltene molecules are generally more hydrophilic and less hydrophobic than other hydrocarbons found in heavy oils. Since the metal sulfide catalyst particles tend to be very hydrophilic, individual particles or molecules will tend to migrate towards the more hydrophilic moieties or molecules in the heavy oil feed.

While the highly polar nature of the metal sulfide catalyst particles causes or allows them to bind to asphaltene molecules, it is the general incompatibility between highly polar catalyst compounds and hydrophobic heavy oil that requires the aforementioned thorough or thorough mixing of the catalyst precursor composition in the heavy oil prior to decomposition and formation of active catalyst particles. Since the metal catalyst compounds are highly polar, they cannot be effectively dispersed in heavy oil if added directly to it. From a practical point of view, the formation of small particles of active catalyst leads to more catalyst particles, which provide more evenly distributed catalytic sites throughout the heavy oil.

IV. Modernized fluidized bed reactor.

In FIG. 4 schematically depicts an exemplary upgraded fluidized bed hydrotreating system 400 that may be used in the disclosed methods and systems. Fluidized bed hydrotreating system 400 includes an upgraded fluidized bed reactor 430 and a hot separator 404 (or other separator such as a distillation column). To create the upgraded fluidized bed reactor 430, catalyst precursor 402 is initially premixed with hydrocarbon diluent 404 in one or more mixers 406 to form catalyst precursor blend 409. Catalyst precursor blend 409 is added to feedstock 408 and mixed with feedstock in one or more mixers 410c. forming a conditioned feedstock 411. The conditioned feedstock is fed into a buffer tank 412 with a circulation pump 414 to cause further mixing and dispersion of the catalyst precursor in the conditioned feedstock.

The conditioned feedstock from the buffer tank 412 is pumped by one or more pumps 416, passes through the preheater 418 and is fed into the fluidized bed reactor 430 along with pressurized hydrogen gas 420 through an inlet 436 located at or near the bottom of the fluidized bed reactor 430. The heavy oil material 426 in fluidized bed reactor 430 contains dispersed metal sulfide catalyst particles, schematically depicted as catalyst particles 424.

The heavy oil feedstock 408 may comprise any desired fossil fuel feedstock and/or fraction thereof, including, but not limited to, one or more heavy oils, tar sands, crude oil sludge, atmospheric column bottoms, bottoms vacuum column, coal tar, liquefied coal and other residue fractions. In some embodiments, the heavy oil feedstock 408 may include a significant high-boiling hydrocarbon fraction (i.e., nominally at or above 343°C (650°F), more preferably nominally at or above about 524°C (975°F)) and/or asphaltenes. Asphaltenes are complex hydrocarbon molecules that include a relatively low ratio of hydrogen to carbon, which is the result of a sufficient number of fused aromatic and naphthenic rings with paraffinic side chains (see Fig. 1). Layers of fused aromatic and naphthenic rings are held together by heteroatoms such as sulfur or nitrogen and/or polymethylene bridges, thioether bonds, and vanadium and nickel complexes. The asphaltene fraction also contains a higher sulfur and nitrogen content than crude oil or the rest of the vacuum residue, and also contains higher concentrations of carbon-forming compounds (ie those that form coke precursors and sludge).

The fluidized bed reactor 430 further includes a loose catalyst zone 442 containing a heterogeneous catalyst 444. A lower heterogeneous catalyst free zone 448 is located below the loose catalyst zone 442, and an upper heterogeneous catalyst free zone 450 is located above the loose catalyst zone 442. Dispersed metal sulfide catalyst particles 424 are dispersed throughout the material 426 in the fluidized bed reactor 430, including the loose catalyst zone 442, heterogeneous catalyst free zones 448, 450, 452, thereby being available to promote enrichment reactions within constituting the catalyst free zones in the reactor with a fluidized bed before its modernization with the inclusion of a two-way catalyst system.

To promote hydrocracking rather than just hydrotreatment reactions, the hydrotreating reactor(s) are 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 operated at a pressure in the range from about 1000 psi (6.9 MPa) to about 3000 psi (20.7 MPa), more preferably in the range from about 1500 psi (10.3 MPa) to about 2500 psi (17.2 MPa), and preferably operate at a space velocity (LHSV) in the range

- 18 041150 from about 0.05 to about 0.45 h ^-1 , more preferably in the range from about 0.15 to about 0.35 h ^-1 . The difference between hydrocracking and hydrotreating can also be expressed in terms of residue conversion (where hydrocracking results in a significant conversion of higher boiling to lower boiling hydrocarbons, whereas this does not occur in hydrotreating). The hydrotreating systems disclosed herein can result in residue conversions ranging from about 40% to about 90%, preferably in the range from about 55% to about 80%. The preferred conversion range generally depends on the type of feedstock due to differences in processing complexity among different feedstocks. Typically, the conversion will be at least 5% higher, preferably at least 10% higher, compared to operating a fluidized bed reactor prior to upgrading with a two-way catalyst system as disclosed herein.

The material 426 in the fluidized bed reactor 430 is continuously recirculated from the upper heterogeneous catalyst free zone 450 to the lower heterogeneous catalyst free zone 448 via a recirculation conduit 452 connected to an ebullation pump 454. which material 426 is diverted from the upper zone 450 free of heterogeneous catalyst. Recycled material 42 6 is mixed with fresh conditioned feed 411 and hydrogen gas 420.

Fresh heterogeneous catalyst 444 is introduced into the fluidized bed reactor 430 through the catalyst inlet pipe 458, and the spent heterogeneous catalyst 444 is withdrawn through the catalyst withdrawal pipe 460. While the catalyst withdrawal pipe 460 is unable to distinguish between completely spent catalyst, partially spent but active catalyst from fresh catalyst, the existence of dispersed metal sulfide catalyst particles 424 provides additional catalytic activity in the loose catalyst zone 442, the recycle channel 452, and in the lower and upper heterogeneous catalyst free zones 448, 450. The addition of hydrogen to hydrocarbons outside of the heterogeneous catalyst 444 minimizes the formation of sludge and coke precursors that are often responsible for deactivating the heterogeneous catalyst.

The fluidized bed reactor 430 further includes an outlet 438 at or near the top through which converted material 440 is withdrawn. 405, which are removed from the top of the hot separator 404, from the residue fraction 407, which is recovered from the bottom of the hot separator or distillation column 404. The residue fraction 407 contains residual metal sulfide catalyst particles, schematically depicted as catalyst particles 424. Optionally, at least a portion of the residue fraction 407 may be recycled back to the fluidized bed reactor 430 to form part of the feed and feed additional metal sulfide catalyst particles. Alternatively, the residue fraction 407 may be further processed using downstream process equipment such as another fluidized bed reactor. In this case, separator 404 may be an intermediate separator.

In some embodiments, operating an upgraded fluidized bed reactor with little sludge fouling using a two-way catalyst system results in reduced equipment fouling at any given sludge rate and/or concentration.

For example, the rate of equipment fouling when operating a retrofit fluidized bed reactor using a two-way catalyst system can result in a purge heat exchanger shutdown frequency that is equal to or less than operating a fluidized bed reactor.

In addition, or alternatively, the equipment fouling rate when operating a retrofit fluidized bed reactor using a two-way catalyst system may result in a frequency of shutdowns of the atmospheric and/or vacuum distillation column for purification that is equal to or less than when the fluidized bed reactor is operated.

In addition, or alternatively, the rate of equipment fouling when operating a retrofit fluidized bed reactor using a two-way catalyst system may result in a filter and pre-filter replacement or cleaning frequency that is equal to or less than when a fluidized bed reactor is operated.

In addition, or alternatively, the equipment fouling rate when operating a retrofit fluidized bed reactor using a two-way catalyst system can result in a switching frequency to spare heat exchangers that is equal to or less than operating a fluidized bed reactor.

In addition, or alternatively, the equipment fouling rate when operating a retrofit fluidized bed reactor using a two-way catalyst system may

- 19 041150 lead to a reduced rate of decrease in skin temperatures in equipment selected from one or more heat exchangers, separators or distillation columns compared to the initial operation of the fluidized bed reactor.

In addition, or alternatively, the rate of equipment fouling when operating a retrofit fluidized bed reactor using a two-way catalyst system may result in a reduced rate of increase in temperature of the furnace tube metal compared to operating a fluidized bed reactor.

In addition or alternatively, the rate of equipment fouling when operating a retrofitted fluidized bed reactor using a two-way catalyst system may result in a reduced rate of increase in the calculated thermal fouling resistance factors of heat exchangers compared to the initial operation of the fluidized bed reactor.

In some embodiments, operating an upgraded fluidized bed reactor using a two-way catalyst system may result in a sludge formation rate and/or concentration that is equal to, less than, or greater than operating the fluidized bed reactor. In some embodiments, the sediment concentration may be based on a measurement of sediment in one or more of: (1) the atmospheric column bottoms product; (2) product bottoms of the vacuum column; (3) hot low pressure separator product; or (4) liquid fuel product before or after the addition of distillate oils.

V. Experimental studies and results.

The following test results data demonstrate the effects and benefits of upgrading a fluidized bed reactor using a two-way catalyst system consisting of a heterogeneous catalyst and dispersed metal sulfide catalyst particles in heavy oil hydrotreating. Comparative studies were performed using a commercial fluidized bed plant and showed that the use of a two-way catalyst system in an upgraded fluidized bed hydrotreating system resulted in little sludge fouling. The setup used for the examples was a three-stage fluidized bed setup. Due to the patent nature of operating a commercial plant, operating parameters are provided in relative rather than absolute terms.

The heavy vacuum gas oil can be used as a hydrocarbon diluent to disperse the catalyst precursor and form a precursor mixture which is then added and mixed with the heavy oil feed to form the conditioned feed. Mixing the amount of catalyst precursor with the amount of hydrocarbon diluent forms an amount of the catalyst precursor blend, which can then be mixed with the heavy oil feed to achieve the target dispersed catalyst loading in the conditioned feed. By way of illustration, where a target loading of 30 ppm is desired. dispersed metal sulfide catalyst in a conditioned feed (where the loading is expressed in terms of metal concentration), a catalyst precursor mixture can be obtained with a metal concentration of 3000 ppm. A high shear mixer can be used to mix a precursor mixture of a hydrocarbon diluent and a catalyst precursor (eg, molybdenum 2-ethylhexanoate) with the heavy oil feedstock to form a conditioned feedstock. Proper mixing can be achieved by first pre-mixing the catalyst precursor with the hydrocarbon diluent to form a precursor mixture.

As mentioned above, the following examples were performed in a commercial fluidized bed plant. The setup used for the examples was a three-stage fluidized bed setup. Due to the patent nature of operating a commercial plant, operating parameters are provided in relative terms.

Comparative example 1.

The commercial fluidized bed plant for Comparative Example 1 was operated as is without the use of the dispersed catalyst additive used to form the dispersed metal sulfide particles of the two-way catalyst system. For the processing of heavy oil feedstock, only a commercial heterogeneous loosened (boiling) supported catalyst was used in a standard amount. The fluidized bed reactors were operated at base temperature with all three reactor stages operated at the same weighted average bed temperature (WABT). The process load was Urals vacuum residue, based on the 538°C (1000°F) boiling point of the residue fraction, and the plant was operated at a base feed rate, usually expressed as liquid hourly space velocity (LHSV), which is defined as the feed space velocity divided by thermal reactor volume.

Under the above basic conditions, a baseline residue conversion was achieved, where the conversion is determined from the calculation of 538° C. + vacuum residue fraction. After leaving the reactor system, the converted reaction stream was processed through a series of separations that included atmospheric distillation and vacuum distillation, resulting in the recovery of the product from the still

- 20 041150 vacuum column residue (VTB). Basal sediment concentration was measured in this VTB product using the IP-375 method.

During operation of the commercial plant in the initial state of comparative example 1, several heat exchangers located downstream of the fluidized bed reactor section were monitored for signs of fouling. They included three heat exchangers in series downstream of the vacuum distillation column, which are used to reduce the temperature of the vacuum column bottoms product. For these examples, they are referred to as VTB Cooler #1, VTB Cooler #2, and VTB Cooler #3. columns, referred to as ATV cooler. The auxiliary fraction is the product stream obtained above the VTB product in the vacuum distillation column. The fouling was measured based on the pressure drop across each of these heat exchangers, measured in pressure units kPa. The pollution rate is expressed as the average daily rate of increase in pressure drop over several days, expressed in kPa/day.

The contamination results are shown below after example 2 in the table. All five monitored heat exchangers showed noticeable fouling rates ranging from 37 kPa/day for the auxiliary coolant to 196 kPa/day for the ATV cooler. The fouling rates for the three VTB coolers ranged from 45 to 124 kPa/day. These rates are significant and indicate the rate of fouling of the heat exchanger sufficient for the necessary regular shutdown of individual heat exchangers for cleaning. To meet this need, the commercial plant was equipped with parallel heat exchangers that allow the key heat exchangers to be cleaned while the plant is still in operation.

Example 2

Example 2 used the same commercial plant as described in Comparative Example 1. However, the plant was modified to operate using a two-way catalyst system containing the same amount of commercial supported heterogeneous loosened (boiling) catalyst along with dispersed metal sulfide catalyst particles formed using a well-dispersed catalyst precursor.

The dispersed catalyst precursor was added to the process feed in an amount sufficient to provide 35 ppm. by weight of the catalytic molybdenum metal based on the amount of raw material of the vacuum residue. The raw material feed rate of the Ural vacuum residue was maintained at the same base rate as in Comparative Example 1.

In Example 2, the reactor temperatures, expressed as the weighted average bed temperature, were increased by 9°C compared to the base temperature used in Comparative Example 1. All three reactor stages were increased in temperature by the same amount and therefore continued to operate on equal terms. WABT in three reactors. This increase in temperature resulted in a 9.4 percentage point increase in residue conversion compared to the baseline conversion in Comparative Example 1. This should typically result in a significant increase in the sediment concentration in the vacuum column bottoms product. However, due to the influence of the two-way catalyst system used in Example 2, the measured sediment concentration (using the IP-375 method) in the vacuum column bottoms was 0.95 times the base concentration of Comparative Example 1, or almost the same sediment concentration.

One skilled in the art would expect that with a sludge concentration that is nearly the same as Comparative Example 1, the method used in Example 2 would be expected to show similar fouling rates of the heat exchanger. However, the actual fouling rates observed for Example 2 were substantially lower than those for Comparative Example 1. As shown in the table, fouling rates for VTB coolers ranged from 0.01 kPa/day for VTB cooler #1 to 41 kPa/day for VTB cooler #3. This equates to an unthinkable 99.9% reduction in fouling rates for VTB cooler #1, 71.1% for VTB cooler #2, and 66.9% for VTB cooler #3. Similarly, fouling rates for cooler #3 auxiliary fraction and coolant ATB were significantly lower than in comparative example 1, with a decrease of 97.3% and 93.4%, respectively.

The observation of a dramatically reduced fouling rate at almost the same IP-375 sludge concentration in the vacuum tower bottoms product indicates that the sludge composition is significantly altered by the dispersed catalyst additive of the present invention and that a sludge with reduced fouling tendency is formed.

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Claims (13)

Comparative Example 2 and Example 1 Not dispersed catalyst Dispersed catalyst (35 ppm Mo in vacuum residue feed) weighted average Basic Base temperature + 9°С layer, °C Residual conversion, W% based on 538°С boiling limits factions Basic Basic + 9.4% Sediment measured by IP-375 method in the bottom of the vacuum column, relative Basic 0.95 * Basic Heat exchanger fouling rate (rate of increase in differential pressure) kPa/day % Reduction in speed pollution VTB Cooler #1 +90 +0.1 99.9% VTB Cooler #2 +45 +13 71.1% VTB Cooler #3 +124 +41 66.9% Auxiliary fraction cooler +37 +1 97.3% ATV Cooler +196 +13 93.4% The present invention may be embodied in other specific forms without departing from its scope or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. Therefore, the scope of the invention is defined by the appended claims and not by the preceding description. All changes that fall within the meaning and equivalence range of the claims are to be embraced within the scope of the claims. CLAIM 1. A method for upgrading a fluidized bed hydrotreatment system that includes one or more fluidized bed reactors to produce negligible sludge fouling, comprising operating a fluidized bed reactor using a heterogeneous catalyst under initial hydrotreating conditions to produce an initial process stream containing conversion products and sludge, including heavy oil hydrotreatment at initial conversion rate, initial sludge formation rate and/or initial sludge concentration in the initial process stream, and initial equipment fouling rate; then upgrading the fluidized bed reactor by forming an upgraded reactor with a two-way catalyst system containing dispersed particles of a metal sulfide catalyst and a heterogeneous catalyst; and operating an upgraded fluidized bed reactor using a two-way catalyst system for heavy oil hydrotreating, wherein said reactor contains a sludge causing minor fouling compared to the sludge in the original process stream, resulting in equipment fouling being reduced by at least 5%. for a given rate of sludge formation and/or concentration, compared to operating a reactor with boiling water - 22 041150 thick layer under initial conditions; where when operating the upgraded fluidized bed reactor using a two-way catalyst system, compared to operating the fluidized bed reactor under initial conditions, the rate of obtaining converted products is increased by at least 2.5%, due to at least one of the following: (i) higher temperature, increased by at least 2.5°C, higher conversion, increased by at least 2.5%, and at a throughput at least the same level compared to the operation of the reactor with a fluidized bed in the initial conditions; (ii) higher temperature increased by at least 2.5°C and higher throughput increased by at least 2.5% and conversion at least the same level compared to operation fluidized bed reactor under initial conditions; (iii) higher temperature increased by at least 2.5°C and higher throughput increased by at least 2.5% and higher conversion increased by at least 2.5% compared with the operation of a fluidized bed reactor under initial conditions; and where the fouling rate of the equipment is determined during the operation of the reactor under initial conditions and during the operation of a modernized fluidized bed reactor using a two-way catalyst system, at least one of the following process parameters: (i) frequency of required cleaning of heat exchangers; (ii) frequency of switching to spare heat exchangers; (iii) frequency of filter changes; (iv) frequency of cleaning or replacement of the coarse filter; (v) the rate of decrease in skin temperatures in equipment, including equipment selected from heat exchangers, separators or distillation columns; (vi) the rate of increase in temperature of the chimney metal; (vii) the rate of increase of the calculated fouling thermal resistance factors of heat exchangers and furnaces; (viii) the rate of increase in pressure drop across the heat exchangers; (ix) cleaning frequency of atmospheric and/or vacuum distillation columns; or (x) frequency of major repairs. 2. The method of claim 1, wherein operating the upgraded fluidized bed reactor using a two-way catalyst system to produce negligible sludge fouling comprises: operating the upgraded fluidized bed reactor at a higher reactor rate than the initial rate of operation, and producing converted products at a rate higher than the initial rate of producing converted products when operating the fluidized bed reactor under initial conditions, and at the same time: sludge formation during operation of the upgraded fluidized bed reactor occurs at a reduced rate and/or concentration compared to the initial sludge formation rate and/or concentration when the fluidized bed reactor is operated under initial conditions; and the fouling of the equipment of the hydrotreating system occurs at a reduced rate compared to the initial fouling rate of the equipment when the fluidized bed reactor is operated under initial conditions, and the fouling rate of the equipment is reduced to a greater extent than the decrease in the rate of formation and/or concentration of sludge. 3. The method of claim 1, wherein operating the upgraded fluidized bed reactor using a two-way catalyst system to produce negligible sediment fouling comprises operating the upgraded fluidized bed reactor at a higher operating rate than the initial reactor operating rate and producing converted products with more high speed than the initial speed of obtaining converted products during operation of the fluidized bed reactor in the initial conditions, and at the same time: sludge formation during operation of the upgraded fluidized bed reactor occurs at a rate and/or concentration that is not higher than the initial sludge formation rate and/or concentration during operation of the fluidized bed reactor under initial conditions; and fouling of the equipment of the hydrotreatment system occurs at a reduced rate compared to the initial fouling rate of the equipment during initial operation of the fluidized bed reactor. 4. The method of claim 1, wherein operating the upgraded fluidized bed reactor using a two-way catalyst system to produce little sediment fouling comprises operating the upgraded fluidized bed reactor at a higher rate. - 23 041150 work than the initial intensity of the reactor, and obtaining converted products at a higher rate than the initial rate of obtaining converted products during operation of the fluidized bed reactor in the initial conditions, and at the same time: sludge formation during operation of the upgraded fluidized bed reactor at a higher rate and/or concentration than the initial rate of formation and/or concentration of sludge during operation of the fluidized bed reactor under initial conditions; and fouling of the equipment of the hydrotreating system occurs at a rate that is lower than the initial fouling rate of the equipment during the operation of the fluidized bed reactor under initial conditions. 5. The method of claim 1, which is characterized by at least two of the following: throughput is increased by at least 5%, at least 10%, or at least 20% when operating the upgraded fluidized bed reactor compared to operating the fluidized bed reactor under initial conditions; conversion is increased by at least 5%, at least 7.5%, at least 10%, or at least 15% when operating the upgraded fluidized bed reactor compared to operating the fluidized bed reactor under initial conditions; or the temperature is increased by at least 5° C., at least 7.5° C., or at least 10° C. when operating the upgraded fluidized bed reactor compared to operating the fluidized bed reactor under initial conditions. 6. The method according to any one of claims 1 to 5, wherein the equipment fouling rate during operation of the upgraded fluidized bed reactor using a two-way catalyst system is reduced by at least 25%, at least 50%, or at least 75% compared to the operation of a fluidized bed reactor under initial conditions. 7. The method according to any one of claims 1 to 6, wherein the deposit formation is determined during the operation of the fluidized bed reactor under initial conditions and during the operation of the upgraded fluidized bed reactor using a two-way catalyst system by at least one of the following indicators: (i) the absolute rate of sedimentation; or (ii) sludge concentration in at least one process stream. 8. The method of claim 7 wherein the sediment concentration is determined in at least one process stream selected from atmospheric distillation column bottom residue, atmospheric column feed, hot low pressure separator product, liquid fuel product, vacuum column bottoms after adding distillate oils. 9. The method according to any one of claims 1 to 8, wherein after upgrading the fluidized bed reactor using a two-way catalyst system, the sludge formation rate and/or concentration is maintained or increased compared to the initial sludge formation rate and/or concentration, and the fouling rate equipment is reduced by at least 5%, at least 25%, at least 50%, or at least 75% compared to the initial equipment fouling rate when the fluidized bed reactor is operated under initial conditions. 10. The method according to any one of claims 1 to 8, wherein after upgrading the fluidized bed reactor using a two-way catalyst system, the rate of sludge formation is increased by at least 2%, at least 10%, at least 20%, or by at least 33% compared to the initial deposit formation rate, and the equipment fouling rate is maintained or reduced compared to the initial equipment fouling rate when the fluidized bed reactor is operated under initial conditions. 11. The method according to any one of claims 1 to 8, in which after upgrading the fluidized bed reactor using a two-way catalyst system, the sludge concentration in the process stream increases by at least 2%, at least 10%, at least 20 % or at least 33% compared to the initial sludge concentration, and the equipment fouling rate is maintained or reduced compared to the initial equipment fouling rate when the fluidized bed reactor is operated under initial conditions. 12. The method according to any one of claims 1 to 8, wherein after upgrading the fluidized bed reactor using a two-way catalyst system, the deposit formation rate is reduced by at least 2%, at least 10%, at least 30%, or by at least 50% compared to the initial deposit formation rate, and the equipment fouling rate is reduced by an even greater percentage compared to the initial equipment fouling rate when the fluidized bed reactor is operated under initial conditions. 13. The method according to any one of claims 1 to 8, in which after upgrading the fluidized bed reactor using a two-way catalyst system, the sediment concentration in the process stream is reduced by at least 2%, at least 10%, at least 30 % or at least 50% compared to the initial sludge concentration, and the equipment fouling rate is reduced by an even greater percentage compared to the initial equipment fouling rate, -