Process for producing kerosene and / or diesel from renewable resources

Abstract

The present disclosure provides a process for increasing the yield of kerosene and / or diesel oil production from a renewable feedstock involving hydrotreating the renewable feedstock and hydroisomerizing the hydrotreated liquid. The isomerized effluent is separated to produce an off-gas stream, at least one fuel stream having a desired boiling point range, and a heavy fraction having a boiling point greater than the desired boiling point range. The heavy fraction is passed to a hydrocracking zone to produce a hydrocracked effluent. The hydrocracked effluent is passed to the hydroisomerization zone.

Description

Technical Field

[0001] The present invention relates to the field of producing kerosene and / or diesel from renewable resources, and in particular to a method for increasing the yield of kerosene and / or diesel from renewable resources. Background Art

[0002] The increase in demand for energy due to economic growth and development in the world has led to an increase in greenhouse gas concentrations in the atmosphere. This is considered one of the most important challenges facing humanity in the 21st century. In order to mitigate the impact of greenhouse gases, efforts have been made to reduce the global carbon footprint. The ability of the Earth system to absorb greenhouse gas emissions has been exhausted. Therefore, the goal is to reach net zero emissions by 2050. In order to achieve these emission reduction targets, the world is transitioning away from traditional carbon-based fossil fuel energy carriers alone. Achieving the energy transition in a timely manner requires multiple approaches in parallel, including, for example, energy conservation, improving energy efficiency, electrification, and efforts to produce fuels and fuel components and / or chemical feedstocks from renewable resources.

[0003] Vegetable oils, oils obtained from algae and animal fats are considered as renewable resources. Also, decomposed materials, such as pyrolyzed recyclable materials or wood, are considered as potential resources.

[0004] Renewable materials may include materials such as triglycerides with very high molecular weight and high viscosity, which means that using them directly or as a mixture for fuel bases is problematic for modern engines. On the other hand, the hydrocarbon chains constituting, for example, triglycerides are substantially linear, and their length (in terms of carbon number) is compatible with the hydrocarbons used / used as fuels. Therefore, it is attractive to convert feeds containing triglycerides to obtain high-quality fuel components.

[0005] Petroleum-derived jet fuels inherently contain paraffins and aromatics. Generally, paraffins provide the most desirable clean-burning characteristics for jet fuels. Challenges with using paraffins from renewable sources include higher boiling points and higher freezing points due to chain length. Solutions to these challenges include cracking to reduce chain length and / or isomerization to increase branching, thereby improving cold flow properties.

[0006] In Marker et al. (US8,314,274, November 20, 2012), a renewable feedstock is hydrogenated / hydrodeoxygenated, then isomerized and selectively hydrocracking to generate an effluent containing branched alkanes. The effluent is separated to provide an overhead stream, an optional aviation product stream, a diesel stream, and a stream with a higher boiling point. A portion of the diesel boiling range product is recycled to the isomerization and selective hydrocracking zone.

[0007] McCall et al. (US 8,742,183, June 3, 2014) relates to a process for producing aviation fuel from a biorenewable feedstock that is subjected to hydrogenation and deoxygenation to provide normal paraffins. Three embodiments of the following subsequent steps are described: (i) isomerizing the normal paraffins and selectively cracking the isomerized effluent, (ii) selectively cracking the normal paraffins and isomerizing the cracked effluent, or (iii) subjecting the normal paraffins to a combined selective cracking and isomerization zone.

[0008] A challenge with isomerization and selective cracking schemes is the conflict between maximizing product yield and meeting product specifications.

[0009] Anumakonda et al. (US8,058,492, November 15, 2011) describe a method for controlling the production of transportation fuels from renewable raw materials by: determining the yield of diesel and aviation components; determining isomerization and selective hydrocracking conditions to obtain the yield; hydrogenating and deoxygenating the renewable raw materials to produce normal paraffins; and isomerizing and selectively hydrocracking the normal paraffins. The diesel and aviation fuel components are fractionated under predetermined conditions. The overhead stream from the fractionator is further fractionated into LPG and naphtha streams. The naphtha stream is optionally recycled to the isomerization zone.

[0010] Although Anumakonda et al. contemplate adjusting conditions to achieve a predetermined yield, as described therein, the effectiveness of the process may be limited when the deoxygenated product is subjected to isomerization and selective cracking.

[0011] Markkanen et al. (EP2141217B1, March 25, 2015; US9,005,429, April 14, 2015) describe a method for preparing aviation fuel by a first-stage hydrodeoxygenation of a biomass feedstock followed by a second-stage isomerization of the resulting n-paraffins. The effluent from the second stage is separated in a fractionator to produce a gas, a gasoline fraction, an aviation fuel fraction, a diesel fraction, and a heavy fraction having a boiling point equal to or higher than 200°C (US'429) or 290°C (EP'217B1).

[0012] In one embodiment of Markkanen et al., the heavy fraction is combined with the hydrodeoxygenation effluent and the combined stream isomerized. In another embodiment, the heavy fraction is isomerized in the first section of the second stage, and after adding the hydrodeoxygenation effluent, the isomerized heavy fraction is isomerized with the hydrodeoxygenation effluent. Finally, in a third embodiment, the hydrodeoxygenation effluent and the heavy fraction are separately isomerized in the second stage and third stage isomerizations, respectively. In the third embodiment of separate isomerization, the catalyst for the heavy fraction can be selected to promote cracking.

[0013] There remains a need to increase the yield of kerosene and / or diesel produced from renewable resources. Summary of the invention

[0014] According to one aspect of the present invention, there is provided a method for increasing the yield of kerosene and / or diesel produced from renewable feedstocks, the method comprising the steps of: reacting the renewable feedstock in a hydrotreating zone under hydrotreating conditions sufficient to cause a hydrotreating reaction to produce a hydrotreated effluent; reacting the hydrotreated liquid in a hydroisomerization zone under hydroisomerization conditions for causing a hydroisomerization reaction to produce an isomerized effluent; separating the isomerized effluent to produce an offgas stream, at least one fuel stream having a desired boiling point range, and a heavy fraction having a boiling point greater than the desired boiling point range; reacting the heavy fraction in a hydrocracking zone under hydrocracking conditions for causing a hydrocracking reaction to produce a hydrocracked effluent; and conveying the hydrocracked effluent to the hydroisomerization zone. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The process of the present invention may be better understood by reference to the following detailed description of preferred embodiments and the accompanying drawings cited therein, in which:

[0016] Figure 1 is a flow chart illustrating one embodiment of the method of the present invention;

[0017] FIG2 is a flow chart showing another embodiment of the method of the present invention; and

[0018] FIG. 3A to FIG. 3E is a graphical representation of the results of the examples presented herein. DETAILED DESCRIPTION

[0019] The present invention provides a method for increasing the yield of kerosene and / or diesel in the hydroprocessing of materials from renewable resources. The renewable feedstock is hydroprocessed. The hydroprocessed effluent from the hydroprocessing zone is conveyed to a hydroisomerization zone to produce an effluent, which is fractionated to provide one or more desired product streams and a recycled heavy fraction. The heavy fraction is first selectively hydrocracked, and then the hydrocracked effluent is conveyed to a hydroisomerization zone.

[0020] It is generally understood that the hydroisomerization zone should be operated at high severity to maximize the yield of isomerized products. However, when the hydroisomerization severity is high, the yield of undesirable and / or less valuable off-gas and / or naphtha increases. The inventors have surprisingly found that by operating at a lower hydroisomerization severity, the yield of the heavy fraction is increased, and by passing the heavy fraction to the hydrocracking zone and then isomerizing the hydrocracking effluent, the yield of the desired isomerized product can be increased.

[0021] The method of the present invention is important for the energy transition and can improve the environment by producing low-carbon energy and / or chemicals from renewable resources, especially from degradable waste sources, while improving the energy efficiency of the method.

[0022] A common challenge in processing renewable raw materials to produce kerosene and / or diesel is the variability of renewable raw materials. The variability of renewable raw materials may include changes from one type of raw material to another type, such as due to changes in supply and / or market, raw material quality and / or composition distribution, seasonal changes, changes between the same raw material sources, etc. Reaction schemes, operating conditions, heat production, process efficiency, product composition and / or product yields may all be affected by this variability. Another challenge to meeting product specifications is that product component yields vary with changes in catalyst activity, and / or change from the beginning of operation to the end of operation. The method of the present invention provides flexibility and robustness to allow for variability of raw materials, changes in catalyst activity and / or changes in desired products, while reducing energy consumption, operating costs and / or carbon footprint. Further, the method of the present invention is more flexible in operating conditions and enables improvements in existing process schemes for processing petroleum-derived raw materials.

[0023] Embodiments of process units for implementing the methods of the present invention are described below and / or shown in the accompanying drawings. For ease of discussion, additional equipment and process steps that can be used in the method for producing kerosene and / or diesel from renewable raw materials are not shown. Additional equipment and / or process steps may include, for example, but are not limited to, pre-processors, heaters, coolers, air coolers, heat exchangers, mixing chambers, valves, pumps, compressors, condensers, quench streams, recirculation streams, slip streams, purge streams, reflux streams, etc.

[0024] Figure 1An embodiment of the method 10 of the present invention is shown. A renewable feedstock 12 is reacted in a hydroprocessing zone 14 to produce a hydroprocessed effluent 16. Hydrogen may be combined with the renewable feedstock 12 stream prior to introduction into the hydroprocessing zone 14, co-fed with the renewable feedstock 12, or added to the hydroprocessing zone 14 independently of the renewable feedstock 12. The hydrogen may be fresh and / or recycled from another unit in the process and / or produced in a HMU (not shown). In another embodiment, hydrogen may be produced, for example but not limited to, by water electrolysis. The water electrolysis process may be powered by renewable energy sources such as solar photovoltaic, wind or hydroelectric power to generate green hydrogen, nuclear energy, or powered by non-renewable energy (grey hydrogen) from other sources.

[0025] As used herein, the terms "renewable raw materials," "renewable feedstocks," and "materials from renewable sources" refer to raw materials from renewable sources. Renewable sources can be animal, plant, microbial, and / or bio-derived or mineral-derived waste materials suitable for producing fuels, fuel components, and / or chemical feedstocks.

[0026] A class of preferred renewable materials is bio-renewable fats and oils, which include triglycerides, diglycerides, monoglycerides, free fatty acids and / or fatty acid esters derived from bio-renewable fats and oils. The example of fatty acid esters includes but is not limited to fatty acid methyl esters and fatty acid ethyl esters. Bio-renewable fats and oils include edible and inedible fats and oils. The example of bio-renewable fats and oils includes but is not limited to algae oil, brown grease, canola oil, carinata oil, castor oil, coconut oil, rapeseed oil, corn oil, cottonseed oil, fish oil, hempseed oil, jatropha oil, lard, linseed oil, butterfat, mustard oil, olive oil, palm oil, peanut oil, rapeseed oil, sewage sludge, soybean oil, soybean oil, sunflower oil, pongamia oil, tallow, used cooking oil, yellow grease, white grease and their combination.

[0027] Another preferred renewable material is a liquid derived from a biomass and waste liquefaction process. Examples of such liquefaction methods include, but are not limited to, (hydro)pyrolysis, hydrothermal liquefaction, plastic liquefaction, and combinations thereof. Renewable materials derived from a biomass and waste liquefaction process can be used alone or in combination with bio-renewable fats and oils.

[0028] The renewable materials used as raw materials in the method of the present invention may contain impurities. Examples of such impurities include, but are not limited to, solids, iron, chlorides, phosphorus, alkali metals, alkaline earth metals, polyethylene, and unsaponifiable compounds. If desired, these impurities may be removed from the renewable raw materials prior to introduction into the method of the present invention. Methods for removing these impurities are known to those skilled in the art.

[0029] The method of the present invention is most advantageous when processing a feed stream comprising substantially 100% renewable feedstock. However, in one embodiment of the present invention, the renewable feedstock may be co-processed with petroleum-derived hydrocarbons. Petroleum-derived hydrocarbons include, but are not limited to, all fractions from petroleum crude oil, natural gas condensate, tar sands, shale oil, synthetic crude oil, and combinations thereof. The present invention is more advantageous for a combined renewable and petroleum-derived feedstock comprising a renewable feed content in the range of 30% to 99% by weight. In one embodiment, the renewable feedstock is co-processed with a heavy fraction from a petroleum refinery. For example, the petroleum-derived feedstock may be a heavy fraction from a gas oil unit.

[0030] In the hydroprocessing zone 14, the renewable feedstock 12 is reacted under hydroprocessing conditions sufficient to cause a reaction selected from a hydroprocessing reaction (including but not limited to hydrodeoxygenation, hydrodenitrogenation, hydrodesulfurization, hydrodearomatization, hydrogenation, hydrodemetallization, and combinations thereof). The reaction is preferably a catalytic reaction, but may include non-catalytic reactions, such as thermal treatment, etc. The hydroprocessing zone 14 may be single-stage or multi-stage. In the case of a catalytic reaction, the hydroprocessing zone 14 may be operated in a slurry, a moving bed, a fluidized bed, and / or a fixed bed operation. In the case of a fixed bed operation, each reactor may have a single catalyst bed or multiple catalyst beds. The hydroprocessing zone 14 may be composed of a single reactor or multiple reactors. The hydroprocessing zone 14 may be operated in a co-current flow mode, a counter-current flow mode, or a combination thereof. Preferably, the hydroprocessing zone 14 is operated in a co-current flow mode.

[0031] The catalyst may be the same or different throughout hydroprocessing zone 14. Hydroprocessing zone 14 may include a single catalyst bed or multiple catalyst beds. The catalyst may be the same throughout a single catalyst bed, optionally a mixture of catalysts may be present, or different catalysts may be provided in two or more layers in the catalyst bed. In embodiments with multiple catalyst beds, the catalyst of each catalyst bed may be the same or different.

[0032] In one embodiment, hydroprocessing zone 14 further comprises a hydrogenation catalyst before the hydroprocessing catalyst. The hydrogenation component can be used in bulk metal form or the metal can be loaded on a carrier. The active metal for hydrogenation includes the catalytically active metals of Group VIII and / or Group VIB, including but not limited to Ni, Co, Mo, W and combinations thereof. Preferably, the hydrogenation catalyst comprises Mo. Suitable carriers include refractory oxides, molecular sieves and combinations thereof. Examples of suitable refractory oxides include but are not limited to alumina, amorphous silica-alumina, titania, silicon dioxide and combinations thereof. Examples of suitable molecular sieves include but are not limited to zeolite Y, zeolite beta, ZSM-5, ZSM-12, ZSM-22, ZSM-23, ZSM-48, SAPO-11, SAPO-41, ferrierite and combinations thereof.

[0033] Hydroprocessing catalyst can be any catalyst suitable for hydroprocessing known in the art. Catalyst metal is usually in oxide state when loaded into reactor, and is preferably activated by reducing or sulfiding metal oxide. Preferably, hydroprocessing catalyst comprises catalytically active metal of VIII family and / or VIB family, including but not limited to Pd, Pt, Ni, Co, Mo, W and their combination. Compared with the oxide form of catalyst, hydroprocessing catalyst in sulfide form is usually more active. Sulfidation process is used to convert catalyst from calcined oxide state into active sulfided state. Catalyst can be presulfided or in situ sulfided. Because renewable raw materials usually have low sulfur content, sulfiding agent is often added to feed so that catalyst keeps sulfided form.

[0034] Preferably, the hydroprocessing catalyst comprises a sulfided catalytically active metal. Examples of suitable catalytically active metals include, but are not limited to, nickel sulfide, cobalt sulfide, molybdenum sulfide, tungsten sulfide, sulfided CoMo, sulfided NiMo, sulfided MoW, sulfided NiW and combinations thereof. The catalyst bed / zone may have a mixture and / or a continuous bed / zone of two types of catalysts, including stacked beds, and may have the same or different catalysts and / or catalyst mixtures. In the case of using such sulfided hydroprocessing catalysts, a sulfur source is usually supplied to the catalyst to keep the catalyst in a sulfided form during the hydroprocessing step.

[0035] Hydroprocessing catalyst can be in-situ or non-in-situ sulfurized. In-situ sulfurization can be realized by supplying a sulfur source to the hydroprocessing catalyst during the operation of the method, usually H2S or H2S precursor (that is, easily decomposed into a compound of H2S, such as dimethyl disulfide, di-tert-nonyl polysulfide or di-tert-butyl polysulfide). Sulfur source can be supplied with feed, hydrogen stream, or provided separately. Another suitable sulfur source is a sulfur-containing hydrocarbon stream with a boiling point in the boiling range of diesel or kerosene co-fed with raw material. In addition, the sulfur compound added in the feed is conducive to controlling catalyst stability, and can reduce hydrogen consumption.

[0036] Hydroprocessing zone 14 may be operated as a single stage process or a multi-stage process. In a preferred embodiment, hydroprocessing zone 14 is operated as a single stage process in a co-current flow mode with one or more fixed beds.

[0037] The product of the hydrotreating reaction is optionally directed to a separation zone 20 to separate the product of the hydrotreating reaction into a vapor phase effluent and a liquid hydrotreated effluent 16. In the case where the catalyst used for the hydroisomerization has a precious metal, a separation zone 20 is provided to remove or at least significantly reduce components that poison or otherwise adversely affect the hydroisomerization catalyst. In the case where non-precious metals are used for the hydroisomerization, separation zone 20 is optional.

[0038] When a separation zone 20 is included, the separation zone 20 has one or more separation units, including, for example, but not limited to, a gas / liquid separator, including hot high-pressure and low-pressure separators, medium-high-pressure and low-pressure separators, cold high-pressure and low-pressure separators, high-pressure and low-pressure strippers, integrated strippers, and combinations thereof. The integrated stripper includes a stripper integrated with hot high-pressure and low-pressure separators, medium-high-pressure and low-pressure separators, and cold high-pressure and low-pressure separators. It will be understood by those skilled in the art that the high-pressure separator operates at a pressure close to the pressure of the hydroprocessing zone 14, which is suitably 0 bar to 10 bar (0 MPa to 1 MPa) lower than the reactor outlet pressure, while the low-pressure separator operates at a pressure lower than the pressure of the previous reactor or the pressure of the previous high-pressure separator in the hydroprocessing zone 14, which is suitably 0 bar to 15 bar (0 MPaG to 1.5 MPaG). Similarly, those skilled in the art will understand that hot means that the hot separator is operated at a temperature close to the temperature of the preceding reactor in hydroprocessing zone 14, which is suitably sufficiently above the water dew point (e.g., ≥10°C, preferably ≥20°C above the water dew point) and sufficiently above the salt precipitation temperature (e.g., ≥10°C, preferably ≥20°C above the salt precipitation temperature), while the intermediate separator and the cold separator are at reduced temperatures relative to the preceding reactor in hydroprocessing zone 14. For example, the cold separator is suitably at a temperature that can be achieved by an air cooler. Intermediate temperatures should be understood to refer to any temperature between the temperatures of the hot separator or the cold separator.

[0039] In addition, separation zone 20 may include one or more processing units, including, for example, but not limited to, membrane separation units, amine scrubbers, pressure swing adsorption (PSA) units, caustic washes, and combinations thereof. The processing units are preferably selected to separate the desired gas phase molecules. For example, an amine scrubber is used to selectively separate H2S and / or carbon oxides from H2 and / or hydrocarbons. As another example, a PSA unit may be used to purify a hydrogen gas stream for recycling to a stripper and / or reactor in hydroprocessing zone 14.

[0040] The hydroprocessed effluents from one or more reactors in hydroprocessing zone 14 may each be processed in a separate embodiment of separation zone 20. The effluents from different reactors / zones may be processed in all or some of the same separation units.

[0041] A portion of the hydroprocessed effluent 16 from the one or more separator units may be returned to the hydroprocessing zone 14 , for example, as a quench stream (not shown) or as a diluent for the feedstock 12 (not shown).

[0042] The hydrotreated effluent 16 (with or without a separation step) is passed to a hydroisomerization zone 24 under hydroisomerization conditions for inducing a hydroisomerization reaction. The hydroisomerization reaction increases branching of the paraffinic compounds produced by the hydroprocessing zone 14, thereby improving the cold flow properties of the fuel.

[0043] The hydroisomerization catalyst can be any suitable catalyst composition known to those skilled in the art. Preferably, the hydroisomerization catalyst comprises a Group VIII metal. More preferably, the hydroisomerization catalyst further comprises a zeolite material. The hydroisomerization catalyst may further comprise a binder and / or a carrier, such as but not limited to silica, alumina, silica-alumina and combinations thereof. Preferably, the Group VIII metal is selected from the group consisting of platinum, palladium, nickel and combinations thereof. When the Group VIII metal is Ni, the hydroisomerization preferably comprises a Group VI metal, preferably Mo or W.

[0044] The zeolite material is preferably selected from the group consisting of Beta, COK-7, EU-1, EU-2, EU-11, IZM-1, MCM-22, NU-10, ZSM-5, ZSM-12, ZSM-22, ZSM-23, ZSM-30, ZSM-35, ZSM-48, ZSM-50, ZSM-57 and combinations thereof.

[0045] The catalyst may be the same or different throughout the hydroisomerization zone 24. The hydroisomerization zone 24 may include a single catalyst bed or multiple catalyst beds. The catalyst may be the same throughout a single catalyst bed, optionally a mixture of catalysts may be present, or different catalysts may be provided in two or more layers in the catalyst bed. In embodiments with multiple catalyst beds, the catalyst in each catalyst bed may be the same or different.

[0046] The hydroisomerization zone 24 is operated in the presence of hydrogen at a pressure in the range of 1 MPa to 30 MPa and a temperature in the range of 260° C. to 400° C. Preferably, the pressure is in the range of 2 MPa to 17 MPa and the temperature is in the range of 300° C. to 380° C. Based on the effluent 16, the LHSV is 0.2 h -1 Up to 4h -1 The ratio of hydrogen to combined liquid supplied to hydroisomerization zone 24 is in the range of 100 nominal L to 1500 nominal L (at standard conditions of 0° C. and 1 atm (0.1 MPa)) / kg combined liquid.

[0047] Hydroisomerization is particularly useful for improving the production of kerosene for jet fuel. To increase kerosene production, the WABT (weighted average bed temperature) in the hydroisomerization zone is typically increased. The WABT is a representative temperature of the catalyst bed assuming an adiabatic reactor with no losses or gains from its surroundings. Those skilled in the art will appreciate that the temperature profile will typically increase from the inlet to the outlet.

[0048] The hydroisomerization conditions and catalyst are selected to favor branching rather than cracking. The inventors have surprisingly discovered that by operating at a lower hydroisomerization severity, the yield of the heavy fraction is increased, and by passing the heavy fraction to a hydrocracking zone and then isomerizing the hydrocracking effluent, the yield of the desired isomerized product can be increased. The severity of the hydroisomerization zone is affected by the type and amount of catalyst, operating temperature, operating pressure, space velocity, etc.

[0049] An advantage of the present invention is that the extent of hydroisomerization can be less severe, thereby allowing a lower WABT compared to conventional processes. In addition, a lower WABT allows for lower operating pressures while maintaining the same flow regime, thereby providing improved opportunities to modify or reuse existing low pressure petroleum refinery equipment for hydroisomerization.

[0050] The product from the hydroisomerization zone 24 is directed to a post-processing section. Various embodiments of the post-processing section can be considered. For example, the post-processing section can be as described in US63 / 245,023 or US63 / 245,009 filed on September 16, 2021, which are incorporated herein by reference. The post-processing section includes one or more product recovery zones 26 to produce the desired product stream. For example, Figure 1 The embodiment of illustrates an off-gas stream 32, a naphtha boiling range stream 34, a kerosene boiling range stream 36, a diesel boiling range stream 38, and a heavy fraction 42. In this embodiment, the off-gas stream 32 suitably comprises C1-C5 hydrocarbons, while the naphtha boiling range 34 suitably comprises C4-C12 hydrocarbons having a boiling range of -12°C to 204°C. The kerosene boiling range stream 36 is preferably composed of C6-C18 hydrocarbons having a boiling range of 90°C to 300°C. In one embodiment, the diesel boiling range stream comprises C8-C26 hydrocarbons having a boiling range of 120°C to 400°C. In this embodiment, the heavy fraction 42 has C17+ hydrocarbons having a boiling point greater than 250°C.

[0051] As another example, the embodiment of Figure 2 illustrates an off-gas stream 32, a naphtha boiling range stream 34, a kerosene boiling range stream 36, and a heavy fraction 42. In this embodiment, the off-gas stream 32 suitably comprises C1-C5 hydrocarbons, while the naphtha boiling range 34 suitably comprises C4-C12 hydrocarbons having a boiling range of -12°C to 204°C. The kerosene boiling range stream 36 is preferably comprised of C6-C18 hydrocarbons having a boiling range of 90°C to 300°C. In this embodiment, the heavy fraction 42 has C17+ hydrocarbons having a boiling point greater than 250°C.

[0052] Figure 1 The exemplary product streams shown in FIG. 1 are applicable to the process embodiment of FIG. 2 , and vice versa.

[0053] In a preferred embodiment, the process is directed to increasing the yield of a kerosene boiling range stream 36. In particular, in a preferred embodiment, the process is directed to a kerosene product that meets the ASTM D7566 specification, wherein a paraffinic kerosene synthesized from hydrotreated esters and fatty acids has a T10 distillation temperature (using ASTM test method D86) maximum of 205°C and a final boiling maximum of 300°C.

[0054] In this case, for Figure 1 In an embodiment of the present invention, at least a portion of the diesel boiling range stream 38 is recycled with the heavy fraction 42. Another portion of the diesel boiling range stream 38 can be discharged as a bleed stream. The product recovery zone 26 can include further separating the diesel boiling range stream 38 into a light diesel stream, which can be discharged, for example, as a bleed stream, and a heavy diesel stream recycled with the heavy fraction 42.

[0055] Additionally, or alternatively, the product recovery zone 26 may include further separation of heavy contaminants from the heavy fraction 42. Depending on the original feedstock and / or processing conditions, there may be heavy contaminants that may not be reactive in the subsequent hydrocracking and / or hydroisomerization zones. In this case, it is preferred to provide a effluent stream of the heaviest portion of the heavy fraction 42. In one embodiment, the effluent stream has substantially the same composition as the heavy fraction 42. In another embodiment, the effluent stream may be a product of further processing and / or separation of the heavy fraction 42 to selectively remove contaminants from the heavy fraction 42.

[0056] In the embodiment of FIG. 2 , the diesel boiling range hydrocarbons are part of the heavy fraction 42 and are recycled for cracking and isomerization to elimination.

[0057] As mentioned above, Figure 1 2 may be comprised of one or more unit operations. For example, the product recovery zone 26 may include a product stripper for stripping entrained and / or dissolved gases from the hydroisomerization zone effluent, a naphtha stripper for producing a stripper offgas stream and a naphtha stream, a naphtha stabilizer, a naphtha rectification column, a naphtha recovery column, an overhead separator, a vacuum fractionator, an atmospheric fractionator, and combinations thereof.

[0058] At least a portion of the heavy fraction 42 is introduced into a hydrocracking zone 44 under hydrocracking conditions sufficient to cause a hydrocracking reaction to produce a hydrocracked effluent. In one embodiment, another portion of the heavy fraction 42 may be directed to further processing for valorizing the heavy fraction 42.

[0059] The hydrocracking catalyst may be any suitable catalyst composition known to those skilled in the art. Preferably, the hydrocracking catalyst comprises a Group VIII metal. More preferably, the hydrocracking catalyst further comprises an acidic material.

[0060] The acidic material can be an amorphous acidic material, a crystalline acidic material or a combination thereof. The amorphous acidic material can be, for example, but not limited to, an amorphous silica alumina. The crystalline acidic material can be selected from the group consisting of: β, COK-7, EU-1, EU-2, EU-11, IZM-1, MCM-22, NU-10, ZSM-5, ZSM-12, ZSM-22, ZSM-23, ZSM-30, ZSM-35, ZSM-48, ZSM-50, ZSM-57 and a combination thereof.

[0061] Preferably, the Group VIII metal is selected from the group consisting of platinum, palladium, nickel and combinations thereof.When the Group VIII metal is Ni, the hydroisomerization catalyst preferably comprises a Group VI metal, preferably Mo or W.

[0062] The hydrocracking catalyst may further comprise a binder and / or support, such as, but not limited to, silica, alumina, silica-alumina, and combinations thereof.

[0063] The hydrocracking zone 44 operates in the presence of hydrogen at a pressure in the range of 1 MPa to 30 MPa and a temperature in the range of 260° C. to 400° C. Preferably, the pressure is in the range of 2 MPa to 18 MPa and the temperature is in the range of 280° C. to 400° C.

[0064] The hydrocracking conditions and catalysts are selected to favor cracking rather than branching.

[0065] exist Figure 1 In an embodiment of the present invention, the hydrocracking zone 44 is disposed above the hydroisomerization zone 24 in a single stage configuration. In this embodiment, the heavy fraction 42 is recycled to a single stage reactor that includes both the hydrocracking zone 44 and the hydroisomerization zone 24. The heavy fraction 42 is first reacted in the hydrocracking zone 44. The hydrocracked effluent from the hydrocracking zone is then conveyed to the hydroisomerization zone 24 where it is combined with the hydrotreated effluent 16 to isomerize the hydrocracking effluent and the hydrotreated effluent simultaneously.

[0066] 2, the hydrocracking zone 44 and the hydroisomerization zone 24 are provided in a two-stage configuration. In this embodiment, the heavy fraction 42 is recycled to the hydrocracking zone 44 and the hydroisomerization zone 24. The heavy fraction 42 is first reacted in the hydrocracking zone 44. The hydrocracked effluent from the hydrocracking zone is then passed to the hydroisomerization zone 24 where it is combined with the hydrotreated effluent 16 to isomerize the hydrocracking effluent and the hydrotreated effluent simultaneously.

[0067] exist Figure 1 In each of the embodiments of FIG. 2 and FIG. 3 , hydroisomerization zone 24 optionally includes a hydrofinishing zone (not shown). During the hydroisomerization step and / or depending on the feedstock used (e.g., cashew nut oil), some aromatics and / or trace amounts of olefins may be present in the effluent of the hydroisomerization zone. In this case, a hydrofinishing step is preferably provided to reduce the aromatic content of the product stream.

[0068] The hydrofining component can be used in bulk metal form, or the metal can be supported on a carrier. The active metal used for hydrogenation includes catalytically active metals of Group VIII and / or Group VIB, including but not limited to Ni, Co, Mo, W and combinations thereof. Preferably, the Group VIII metal is selected from the group consisting of platinum, palladium, nickel and combinations thereof. Suitable carriers include refractory oxides. Examples of suitable refractory oxides include but are not limited to alumina, amorphous silica-alumina, titania, silica and combinations thereof.

[0069] In the process 10 of the present invention, the recycle amount of the heavy fraction 42 can be selected to be 20% to 200% by weight of the renewable feedstock 12 entering the isomerization bed, preferably in the range of 30% to 100% by weight of the renewable feedstock 12.

[0070] Example

[0071] The following non-limiting examples of embodiments of the methods of the present invention claimed herein are provided for illustrative purposes only.

[0072] Example 1

[0073] A catalyst bed consisting of 30 mL of a hydroisomerization catalyst containing 0.7 wt% Pt on a support containing 75 wt% silica and 25 wt% zeolite ZSM-12 was placed in the reactor. The catalyst was diluted 1:1.5 with 0.05 mm diameter silicon carbide particles. The silicon carbide particles were applied to mitigate reactor wall effects that could interfere with uniform liquid distribution over the catalyst bed cross section.

[0074] The temperature of the bed was controlled by means of an oven. The catalyst bed was operated at a WABT of 320°C. The hydrotreated effluent was supplied to the catalyst bed at a WHSV of 1.0 g fresh liquid / mL catalyst / hour. The hydrotreated liquid was produced by deoxygenating soybean oil. A gas stream containing 100% volume % hydrogen was supplied to the top bed at a gas-to-oil ratio of 500 NL / kg. The total pressure at the reactor outlet was 73 bar (7.3 MPag).

[0075] The degree of conversion of the feedstock was determined in a number of ways. The hydrocarbon liquids were analyzed using two-dimensional gas chromatography to determine the molecular composition of the hydrocarbon products (in terms of normal paraffinic species, isoparaffinic species, cycloparaffinic species, and aromatic species), and by ASTM D2887 simulated distillation to determine the boiling range distribution. The improvement in cold flow properties and density was measured using the ASTM D2500 method.

[0076] Prior to hydroisomerization, the hydrotreated liquid had cold flow properties measured as a cloud point of 27° C. After hydroisomerization, the cloud point dropped to -7° C., an improvement of 34 degrees Celsius.

[0077] The gaseous effluent was analyzed using gas chromatography.

[0078] The results measured by two-dimensional gas chromatography are shown in Table 1 in weight %.

[0079] The combined yield description based on analysis of the gas effluent and simulated distillation analysis of the hydrocarbon liquid is shown in Table 2.

[0080] Comparative Example 2

[0081] Example 1 was repeated three times with the WABT increased to 330°C, 340°C and 345°C as the only change from Example 1.

[0082] FIG. 3A to FIG. 3E The hydroprocessing effluent ( Figure 3A ), WABT=320℃( Figure 3B ), WABT=330℃( Figure 3C )、WABT=340℃( Figure 3D ) and WABT=345℃( Figure 3E ) of normal paraffins, mono-branched isoparaffins, di-branched isoparaffins and multi-branched isoparaffins.

[0083] Table 1

[0084]

[0085] *C 14 and lighter compounds

[0086] **C 19 and heavier compounds

[0087] Table 2

[0088]

[0089] Where woff is the weight % based on fresh feed

[0090] Table 1 shows that the degree of isomerization of the effluent, reported as cloud point and molecular composition measured by two-dimensional gas chromatography, increases as the HIS zone temperature increases. As expected, increased HIS severity improves the degree of isomerization.

[0091] However, Table 2 shows that more severe operation at elevated reactor temperatures simultaneously results in more extensive cracking, leading to increased yields of undesirable gases and naphtha, while at the same time achieving a maximum in the desired kerosene yield.

[0092] It is generally understood that increasing the severity of hydroisomerization conditions results in an increase in the yield of isomerized products. However, there is an accompanying increase in cracking reactions, which increases the yield of lower value and / or undesirable gas and / or naphtha. The inventors surprisingly found that by operating with lower severity (e.g., under mild to medium hydroisomerization conditions), a higher yield of heavy fractions and lower yields of gas and naphtha were produced. According to the present invention, by operating at a lower severity HIS zone to intentionally increase the heavy fraction yield, by transferring the heavy fraction to a hydrocracking zone to produce a hydrocracked effluent, and then hydroisomerizing the hydrocracked effluent, the yield of the desired isomerized product is significantly increased.

[0093] The method 10 of the present invention allows for variability in renewable feedstocks, including changes from one type of feedstock to another, for example due to changes in supply and / or market, feedstock quality and / or composition distribution, seasonal changes, changes between sources of the same feedstock, etc. The method of the present invention 10 provides flexibility in meeting diesel and / or kerosene product specifications despite changes in reaction schemes, operating conditions, heat production, process efficiency, product composition, and / or product yields affected by such variability, even changes in product component yields due to changes in catalyst activity and / or changes from the beginning of a run to the end of a run. The method 10 of the present invention provides flexibility and robustness to allow for variability in feedstocks, changes in catalyst activity, and / or changes in desired products while reducing energy consumption, operating costs, and / or carbon footprint. In addition, the method of the present invention can improve existing process schemes for processing petroleum-derived feedstocks.

[0094] Although embodiments have been described with reference to various implementations and utilization modes, it should be understood that these embodiments are exemplary and the scope of the subject matter of the present invention is not limited thereto. Many variations, modifications, additions and improvements are possible. Various combinations of the technology provided herein can be used.

Claims

1. A method for increasing the yield of kerosene and / or diesel produced from renewable raw materials, the method comprising the following steps: reacting the renewable feedstock in a hydroprocessing zone under hydroprocessing conditions sufficient to cause a hydroprocessing reaction to produce a hydroprocessed effluent; reacting the hydrotreated liquid in a hydroisomerization zone under hydroisomerization conditions for causing a hydroisomerization reaction to produce an isomerized effluent; separating the isomerized effluent to produce an off-gas stream, at least one fuel stream having a desired boiling point range, and a heavy fraction having a boiling point greater than the desired boiling point range; reacting the heavy fraction in a hydrocracking zone under hydrocracking conditions for causing a hydrocracking reaction to produce a hydrocracked effluent; as well as The hydrocracking effluent is passed to the hydroisomerization zone.

2. The method of claim 1, wherein the at least one fuel stream is selected from the group consisting of a naphtha boiling range product stream, a kerosene boiling range product stream, a diesel boiling range product stream, and combinations thereof.

3. The process of claim 1, wherein the hydroisomerization conditions and the hydroisomerization catalyst are selected to favor branching over cracking, and the hydrocracking conditions and the hydrocracking catalyst are selected to favor cracking over branching.

4. The process according to claim 1, wherein the hydroisomerization conditions include a temperature in the range of 260°C to 400°C, preferably in the range of 300°C to 380°C, and a pressure in the range of 1 MPa to 30 MPa, preferably in the range of 2 MPa to 17 MPa.

5. The process of claim 1 wherein the hydroisomerization conditions and the hydroisomerization catalyst are selected to operate at mild or moderate hydroisomerization severity.

6. The process of claim 1 wherein the hydroisomerization step is conducted with a hydroisomerization catalyst comprising a Group VIII metal and a zeolite material.

7. The process according to claim 1, wherein the hydrocracking conditions include a temperature in the range of 260°C to 400°C, preferably in the range of 280°C to 400°C, and a pressure in the range of 1 MPa to 30 MPa, preferably in the range of 2 MPa to 18 MPa.

8. The process of claim 1 wherein the hydrocracking step is performed with a hydrocracking catalyst comprising a Group VIII metal.

9. The method of claim 8, wherein the hydrocracking catalyst further comprises an acidic material.

10. The process of claim 1 wherein the hydrocracking zone and the hydroisomerization zone are arranged in a stacked bed configuration in a single reactor.

11. The process of claim 1 wherein the hydrocracking zone and the hydroisomerization zone are arranged in series in a reactor.

12. The process of claim 1 wherein the hydroprocessing zone further comprises a separation zone for separating the product of the hydroprocessing reaction into a vapor phase effluent and a liquid hydroprocessed effluent.

13. The method of claim 1, wherein the renewable feedstock is selected from the group consisting of one or more biorenewable fats and oils, liquids derived from a biomass to liquefaction process, liquids derived from a waste to liquefaction process, and combinations thereof.

14. The method of claim 1, further comprising adding a petroleum-derived feedstock for co-processing with the renewable feedstock, preferably in an amount to produce a feed stream comprising 30% to 99% by weight of the renewable feedstock.

15. The method of claim 1, further comprising the step of hydrofinishing the isomerized effluent.

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