Process for the production of transportation fuels

Abstract

The present invention relates to a method and process plant for producing a hydrocarbon composition useful as a transportation fuel in accordance with commercial transportation fuel specifications from a hydrocarbonaceous feedstock containing at least 0.5% by weight of oxygen and at least 25% by weight of carbon in cyclic structures, the method and process plant comprising the steps of: a. subjecting a hydrocarbonaceous feedstock to hydroprocessing in one or more steps to provide an intermediate product containing less than 0.1 wt. % oxygen and, for fractions boiling in the range established by said commercial transportation fuel specifications, a specific gravity exceeding the upper specific gravity limit of said commercial transportation fuel specifications; b. providing from said intermediate product, optionally by fractionation, a hydrotreated hydrocarbon stream for hydroconversion, said fraction for hydroconversion meeting or exceeding the T 0 of said commercial transportation fuel specifications. 95 Less than T 50 4. The method of claim 3, c. directing said hydroconversion stream into contact with a hydroconversion catalyst under hydroconversion conditions to provide a hydroconverted hydrocarbon stream; d. Fractionating said hydroconverted hydrocarbon stream to provide at least said hydrocarbon composition useful as a transportation fuel.

Description

[Technical field]

[0001] The present invention relates to a method for producing high quality transportation fuels by hydroconversion of liquid cyclic hydrocarbonaceous feedstocks, which may be formed by thermochemical cracking of solid hydrocarbonaceous materials, such as tires or lignocellulosic solids. [Background technology]

[0002] Thermochemical decomposition, e.g., pyrolysis or hydrothermal liquefaction (HTL), of certain feedstocks with aromatic structures, such as waste tires and rubber, provides liquids (for convenience, pyrolysis oil) with a high content of aromatics and ring structures such as naphthalenes. Similar liquids may also be provided as tar from the pyrolysis of coke ovens and lignite. Although most such pyrolysis oils boil in the middle distillate range, the predominance of cyclic compounds means that such cyclic pyrolysis oils boiling in the middle distillate range are not suitable for use as high quality middle distillate transportation fuels. Summary of the Invention

[0003] We have now discovered a potential process for the conversion of such cyclic pyrolysis oils into middle distillate transportation fuels which involves treating cyclic pyrolysis oils boiling in the middle distillate range in the presence of a hydroconversion catalyst at elevated pressure.

[0004] When a feedstock, such as pyrolysis oil, boils above the boiling range of the desired products, it is known to perform hydrocracking on the feedstock to reduce its molecular weight, and therefore its boiling point. Since hydrocracking entails losses in product yield, it is common practice to fractionate the feedstock by distillation so that only feedstocks boiling above the desired range are directed to hydrocracking in order to minimize the losses in product yield.

[0005] However, in this disclosure we have determined that when cyclic feedstocks having boiling ranges overlapping with the desired boiling range are subjected to hydroconversion, high yields of high quality transportation fuels can be obtained.

[0006] The process is more selective towards saturating aromatics as well as adding hydrogen to cyclic structures when the hydrogen partial pressure is increased (eg, by increasing the total process pressure).

[0007] definition As used herein, the term "thermochemical decomposition" is intended for convenience to be used broadly for any decomposition process in which materials are partially decomposed at elevated temperatures (typically from 250° C. to 800° C. or even 1000° C.) in the presence of less than stoichiometric amounts of oxygen (including without oxygen). The products are typically combined liquid and gas streams and a quantity of solid char. The term should be interpreted to include the processes known as pyrolysis and hydrothermal liquefaction, both in the presence and absence of a catalyst.

[0008] For simplicity, all products from thermochemical decomposition, such as pyrolysis and thermal liquefaction, will hereinafter be referred to as pyrolysis oils, regardless of the nature of the original process.

[0009] When concentrations in the gas phase are given, they are given as molar concentrations unless otherwise specified.

[0010] In the following, the abbreviation % by volume will be used to indicate volume percent with respect to gas.

[0011] When concentrations in liquid or solid phases are given, they are given as weight concentrations unless otherwise specified.

[0012] In the following, ppm w The abbreviation "parts per million" shall be used to indicate the amount of sulfur atoms relative to the amount of a liquid hydrocarbon stream, for example.

[0013] In the following the abbreviation wt.% will be used to indicate percent by weight.

[0014] The term aromatic molecule shall be used for the purposes of this application to denote monocyclic rings having a conjugated stable bond structure according to IUPAC nomenclature, containing only carbon atoms in the aromatic ring, as well as heterocyclic rings containing one or more atoms other than carbon and hydrogen, such as oxygen and nitrogen. The term shall also encompass both conjugated monocyclic and polycyclic rings, including fused aromatic rings.

[0015] The aromatic content of a liquid, according to the art, is the total mass of molecules having at least one aromatic structure relative to the total mass (%) of all molecules.

[0016] The content of carbon in cyclic structures is the total mass (%) of carbon atoms in a molecule having at least one cyclic structure relative to the total mass of carbon in all molecules, according to the definition of aromatic content.

[0017] Pressures and temperatures are interpreted hereinafter as pressures and temperatures, respectively, at the inlet of the reactor, in accordance with the terminology of the person skilled in the purification art.

[0018] Hydrogen partial pressure is understood to be the partial pressure of hydrogen in the treat gas.

[0019] Space velocity is hereinafter interpreted in accordance with the terminology of those skilled in the refining art as LHSV (liquid hourly space velocity) in a single catalytically active material, unless otherwise stated.

[0020] The initial boiling point (IBP), final boiling point (FBP) and the temperatures corresponding to the recovery of the sample are understood according to the ASTM D86 standard. The T5, T10, T50 and T95 boiling points are therefore understood as the distillation temperatures at which 5%, 10%, 50% and 95% by volume are recovered, respectively.

[0021] Detailed Description The conversion of biomass and waste materials into liquid products by thermochemical cracking, such as pyrolysis and thermal liquefaction, especially with subsequent hydrotreating, is considered to be an environmentally friendly source for alternatives to petroleum products, especially in terms of global warming. Due to the nature of these liquid products (for simplicity, pyrolysis oils, regardless of the original process), they require upgrading, for example by hydrotreating to remove heteroatoms such as sulfur and oxygen and to hydrogenate olefin structures. The nature of the formation means that the products are not stabilized and therefore, unlike typical fossil feedstocks, they are very reactive, require large amounts of hydrogen, release a significant amount of heat during the reaction, and also have a high tendency to polymerize. The release of heat can further increase polymerization, and at elevated temperatures the catalyst can also be deactivated by coking.

[0022] The thermochemical cracking process plant section that provides the hydrocarbonaceous feedstock according to the present disclosure may be in many forms, including a rotating oven, a fluidized bed, a transported bed, or a circulating fluidized bed, as is known in the art. The cracking converts the pyrolysis feedstock into solids (char), high boiling liquids (tar), and fractions that are gaseous at elevated temperatures. The gaseous fractions include fractions that are condensable at standard temperatures (pyrolysis oil or condensate, C5+ compounds) and fractions that are non-condensable (pyrolysis gas, including pyrolysis off-gas). For example, the thermochemical cracking process plant section (pyrolysis section) may include a pyrolyzer unit (pyrolysis reactor), cyclone(s) and / or filters to remove particulate solids, such as char, and a cooling unit, thereby producing a pyrolysis off-gas stream and said pyrolysis oil stream, i.e., condensed pyrolysis oil. The pyrolysis gas stream contains light hydrocarbons, such as C1-C4 hydrocarbons, and also typically H2O, CO, and CO2. Typically, the term pyrolysis oil includes condensates and tars, and pyrolysis oil streams from pyrolysis of biomass may also be referred to as bio-oil or bio-crude. Pyrolysis oil is a liquid material that is usually rich in a blend of molecules consisting of more than 200 different compounds, mainly oxygenates, such as acids, sugars, alcohols, phenols, guaiacols, syringols, aldehydes, ketones, furans, and other mixed oxygenates resulting from the depolymerization of solids treated in pyrolysis. Thermochemical decomposition of non-biological wastes, including used tires, with suitable compositions such as plastic parts or rubber, provides only products containing low concentrations of oxygen unless oxygen is added to the decomposition process, generally providing a hydrocarbonaceous feedstock with a structure similar to that of tar from a coke oven.

[0023] For the purposes of the present invention, the pyrolysis section may be fast pyrolysis, also called flash pyrolysis in the art. Fast pyrolysis means the thermochemical decomposition of solid renewable feedstocks, typically in the absence of oxygen, at temperatures typically in the range of 350-650 ° C, for example about 500 ° C, with reaction times of 10 seconds or less, for example 5 seconds or less, for example about 2 seconds. Fast pyrolysis can be carried out, for example, by autothermal operation, for example in a fluidized bed reactor. The latter is also called autothermal pyrolysis, characterized by the use of air (optionally together with an inert gas or a recycle gas) as fluidizing gas. Thereby, the partial oxidation of the pyrolysis compounds produced in the pyrolysis reactor (autothermal reactor) provides the energy for the pyrolysis, while at the same time improving the heat transfer. In the so-called catalytic fast pyrolysis, a catalyst can be used. To upgrade the pyrolysis vapors, acid catalysts, typically containing zeolites and free of active metals, can be used, which can be operated in both in-situ mode (catalyst is located within the pyrolysis reactor) and ex-situ mode (catalyst is placed in a separate reactor). The use of catalysts provides the advantage of helping to stabilize the pyrolysis oil, thereby making it easier to hydroprocess. In addition, enhanced selectivity towards the desired pyrolysis oil compounds can be achieved.

[0024] In some cases, hydrogen is added to catalytic pyrolysis, which is then called reactive catalytic rapid pyrolysis. When catalytic pyrolysis is carried out at high hydrogen pressure, for example, above 0.5 MPa, it is often called catalytic hydrogenation pyrolysis. Catalysts for upgrading in the presence of hydrogen typically contain one or more metals active in hydrogenation, for example, metals from group 6 or groups 8, 9 or 10.

[0025] The pyrolysis step can be a fast pyrolysis carried out without the presence of a catalyst and hydrogen, i.e., the fast pyrolysis step is not a catalytic fast pyrolysis, a hydrogenation pyrolysis or a catalytic hydrogenation pyrolysis, which allows for a much simpler and cheaper process.

[0026] The thermochemical decomposition section may be hydrothermal liquefaction. Hydrothermal liquefaction refers to the thermochemical conversion of solid waste and biomass to liquid fuels by treatment in a high-temperature pressurized water environment for a time sufficient to decompose the solid polymeric structures into mainly liquid components. Typical hydrothermal treatment conditions are temperatures ranging from 250 to 375 °C, or even up to 500 °C, and operating pressures ranging from 4 to 40 MPa. This technique offers the operational advantages of lower temperatures, higher energy efficiency, and the advantage of producing products with lower oxygen content compared to pyrolysis, e.g., fast pyrolysis.

[0027] Finally, other related thermochemical decomposition methods are intermediate or slow pyrolysis, where the conditions involve lower temperatures and generally higher residence times; these methods may also be known as carbonization or torrefaction. The main advantage of these thermochemical decomposition methods is the lower investment, but they may also have specific advantages with respect to specific feedstocks or with respect to specific product requirements, such as the need for biochar.

[0028] Where large amounts of solid products are produced, such as in processes for producing biochar, or where it is desirable to recover unconverted carbon black particles from the thermochemical conversion of used tires, it may be beneficial to filter the liquid products as part of the thermochemical conversion process, which also has the advantage of minimizing downstream catalyst deactivation.

[0029] The conversion of hydrocarbonaceous feedstocks containing oxygenates to hydrocarbons is a common method for producing renewable transportation fuels from fats and oils, although reactivity and other properties vary for different feedstocks. The cyclic hydrocarbonaceous feedstock of the present disclosure typically contains a large amount of cyclic structures and may also contain oxygenates selected from the group consisting of ketones, aldehydes or alcohols, but generally contains only small amounts of carboxylic acids. It can be derived from the thermochemical decomposition of non-biological waste such as plastic or rubber parts, including used tires, as well as from lignin-rich biological materials, such as straw, and waste from wood processing or solid fossil feedstocks, such as lignite, typically after pyrolysis and / or catalytic decomposition processes. When the feedstock is of biogenic origin, the feedstock and products have a total carbon content of more than 0.5 parts per trillion. 14 C content, although this ratio may be different if the feedstock contains waste of fossil origin, e.g. plastics.

[0030] The production of hydrocarbon products typically requires one or more hydroprocessing steps, most commonly hydrotreating to remove heteroatoms and saturate double bonds, hydroisomerization to adjust the hydrocarbon molecular structure, and hydroconversion to reduce the hydrocarbon molecular weight, although hydrodearomatization is also suitable according to the present disclosure. During hydrotreating, the hydrocarbonaceous feedstock is combined with excess hydrogen and reacted in a hydrodeoxygenation process, in which water is released from the oxygenates. If the oxygenates contain carbonyl groups, decarboxylation and decarbonylation processes releasing carbon dioxide and carbon monoxide may also occur, in which case there is an equilibrium between carbon dioxide and carbon monoxide according to the water / gas shift process, which is less common in the type of cyclic hydrocarbonaceous feedstock according to the present disclosure. For pyrolysis oils derived from rubber and plastics, the oxygen content is low, for example 0.5% to 5% by weight, whereas for pyrolysis oils derived from wood compounds, the oxygen content is higher, for example 5%, 10% or even 25% to 50% by weight of the oxygenate feedstock, and therefore a significant amount of the product stream is water, carbon dioxide and carbon monoxide. In addition, depending on the nature of the feedstock and the side reactions occurring, a certain amount of light hydrocarbons may also be present in the product stream. Hydroprocessing may also include extraction of other heteroatoms, especially nitrogen and sulfur, but also possibly extraction of halogens and silicon, as well as saturation of double bonds. In particular, hydroprocessing of oxygenates is very reactive and exothermic, and catalysts with moderate or low activity may be preferred to avoid excessive heat release and runaway reactions that lead to coke formation that deactivates the catalyst. Catalyst activity is generally controlled by using only small amounts of active metals and by limiting the amount of promoter metals, especially nickel and cobalt. Generally, such materials with moderate activity are followed by more active materials to ensure near complete hydrotreating. Catalytically active materials in hydroprocessing usually contain at least 1 wt%, at least 5 wt%, or at least 8 wt%, up to 15 wt%, at most 20 wt%, or at most 25 wt%, of molybdenum or tungsten, promoted by an amount of nickel ranging from 0.01:1 Ni:Mo+W to 0.1:1 Ni:Mo+W (wherein said ratio represents the molar ratio between the amount of Ni and the total amount of Mo and W), on a (typically amorphous) refractory oxidant support, such as alumina, silica or titania. Corresponding active catalysts may contain higher amounts of Ni, for example 0.1:1 Ni:Mo+W to 0.5:1 Ni:Mo+W, while even higher ratios typically correspond to hydrodearomatization catalysts. In these compositions, cobalt may have an effect similar to that of nickel. The catalysts may contain further components, such as boron or phosphorus, in combination with the active metal and / or support. The conditions are typically a temperature in the range of 250 to 400°C, a pressure in the range of 3 to 15 MPa, and a heating time of 0.1 to 2 hours. -1 is the liquid hourly space velocity (LHSV) in the section. Deoxygenation involves a combination of hydrodeoxygenation to produce water and, if the oxygenate contains a carboxyl group, e.g., an acid or ester, decarboxylation to produce CO2. Deoxygenation of the carboxyl group (if present) may proceed by hydrodeoxygenation or decarboxylation, with selectivities that may vary from over 90% hydrodeoxygenation to over 90% decarboxylation, depending on the conditions and the nature of the catalyst. Similarly, sulfur is removed by hydrodesulfurization, typically producing H2S. Hydrodesulfurization and deoxygenation by both routes are exothermic, and with the presence of large amounts of oxygen, the process may include intermediate cooling, for example, by quenching with cold hydrogen, feed or product. The feedstock may preferably contain an amount of sulfur to maintain the sulfidation of the metals in order to maintain the activity of the metals. If the feed stream containing oxygenates is at 10, 100 or 500 ppm w If the feedstock contains less than about 100% sulfur, a sulfide donor such as dimethyl disulfide (DMDS) is typically added to the feedstock.

[0031] If the unstabilized feedstock is highly reactive, pretreatment at moderate conditions may be appropriate to stabilize the feedstock. This includes low inlet temperatures of 80°C, 120°C or 200°C, pressures in the range of 3-15 MPa, and a reaction time of 0.1-2 hr. -1 These may include deliberate selection of less active catalysts such as unpromoted or weakly promoted molybdenum (e.g., at concentrations of 5% to 15% by weight on a refractory support).Due to the reactive components and exothermic nature, heat control by quenching or recycling may be important in this pretreatment step.

[0032] When the feedstock structure is cyclic, the hydrotreating process may result in products rich in aromatic molecules and naphthenes. These molecules have poor diesel properties, including density (specific gravity) and cetane index. Traditionally, aromatic molecules have been converted by saturation over hydrotreating catalysts. Because the equilibrium between aromatic and non-aromatic rings favors aromatics at high temperatures, moderate temperature, and therefore high activity, catalysts are preferred, which has involved the use of noble metals, which are catalytically active at lower temperatures than sulfided base metals. However, for typical hydrocarbonaceous feedstocks from thermochemical cracking of cyclic solid materials, simply saturating the aromatic structures may not be sufficient to obtain density or cetane index values ​​compliant with diesel fuel specifications, and therefore additional measures are required.

[0033] Hydroconversion chemically involves the breaking of carbon-carbon bonds in hydrocarbons by the addition of hydrogen. This process is typically used in the form of hydrocracking to adjust the boiling point characteristics of hydrocarbon mixtures by breaking larger molecules into smaller ones, but the breaking of carbon-carbon bonds also has the effect of ring-opening in cyclic molecules. This ring-opening has the associated effect of shifting the equilibrium of hydrodearomatization by converting non-aromatic products so that the reaction is no longer limited by equilibrium, and therefore ring-opening has the indirect effect of reducing the content of aromatic compounds. Typically, hydroconversion involves bringing the intermediate feedstock into contact with a hydroconversion catalyst comprising an active metal (either an elemental precious metal such as platinum and / or palladium, or a sulfide base metal such as nickel, cobalt, tungsten and / or molybdenum), an acidic support (typically a molecular sieve with a topology such as MFI, BEA and FAU, which exhibits high activity in breaking carbon-carbon bonds), and a refractory support (e.g. alumina, silica or titania, or a combination thereof). The catalyst may contain further components such as boron or phosphorus. Conditions are typically at temperatures in the range of 250-400°C, pressures in the range of 3-25 MPa, and for 0.5-8 hr. -1The liquid hourly space velocity (LHSV) of the hydroconversion catalyst is preferably between 10 and 25 MPa, optionally with intermediate cooling by quenching with cold hydrogen, feedstock or product. If the objective involves saturation of aromatic compounds, the pressure is preferably high, for example 10-25 MPa. The hydroconversion catalyst composition may in fact also catalyze the hydrotreating reaction, but according to the present disclosure it is preferred to separate the exothermic hydrotreating reaction from the hydroconversion reaction, since too high a temperature in the presence of the hydroconversion catalyst may result in undesirable excessive cracking and other side reactions, sacrificing yield or catalyst life. Thus, an upstream hydrotreating step with complete or near complete hydrotreating is generally preferred. The determination of the exact conditions requires experimental optimization well known to those skilled in the art (by combined optimization of temperature, space velocity, catalyst material and hydrogen pressure), with the determination of the severity at which the specific gravity is reduced to a specified range while the boiling point is not substantially changed. For the production of diesel fuel, the T of the specification 95 Generally, the T is 360° C. and the specific gravity specification may be 0.81 to 0.96, so that the hydroconversion step (c) of the process is carried out at a T of less than 360° C. 50 and receiving a hydrotreated hydrocarbon stream having a specific gravity greater than 0.96, i.e., a stream that substantially meets the boiling point criteria of the diesel specification but does not meet the specific gravity criteria. 95 Generally, the T is 300° C. and the specific gravity specification may be 0.78 to 0.82, so that the hydroconversion step (c) of the process is carried out at a T of less than 300° C. 50and a hydrotreated hydrocarbon stream having a gravity greater than 0.82, i.e., a stream that substantially meets the boiling point criteria of the diesel specification but does not meet the gravity criteria. In either case, the hydroconversion process has a balanced severity to convert significant amounts of aromatic, olefinic and cyclic bonds without cracking substantial amounts of the hydrocarbons into smaller molecules, which reduces the gravity and increases the hydrogen content in a manner not obtainable by hydroprocessing alone. When applying the disclosed method to pyrolysis oil from used tires, the relevant commercial transportation fuel specifications may be primarily for diesel and marine fuels, since jet and naphtha specifications may require other processes to be met.

[0034] Since hydroconversion catalysts also inherently have hydrotreating activity, the nomenclature known to those skilled in the art is emphasized. Hydrotreating catalysts do not exhibit significant hydroconversion activity, do not contain catalytically active amounts of zeolites, molecular sieves or silica-alumina, and carbon-carbon single bonds are not affected by contact with hydrotreating catalysts. Nevertheless, the molecular structure can be altered during hydrotreating, for example by releasing oxygen atoms that characterize the molecular structure.

[0035] Similarly, the definition of a hydroconversion catalyst relative to a hydroisomerization catalyst is also appropriate. Hydroisomerization catalysts inherently have side reaction activity for hydroconversion. The nature of hydroconversion involves the consumption of hydrogen by ring opening and hydrocarbon cleavage. For the purposes of this disclosure, a catalytic process should be considered a hydroisomerization process if at least 50% of the change in the hydrocarbonaceous molecule occurs without the net addition of hydrogen to the hydrocarbonaceous molecule, as opposed to, for example, hydrotreating, which replaces heteroatoms with hydrogen, or hydroconversion, which breaks carbon-carbon bonds by hydrogen insertion, without significant modification and saturation of double bonds and aromatic structures.

[0036] As previously mentioned, hydroconversion involves the breaking of carbon-carbon bonds, and since the boiling points of shorter hydrocarbon molecules are lower than those of longer molecules, hydroconversion involves the loss of high boiling products to lower boiling products. While raw products boiling in the naphtha range (80-150°C), products boiling in the aviation range (150-290°C) and products boiling in the diesel range (150-390°C) may be of similar value, cracking involves the shortening of carbon molecules and thus the loss of mass of liquid products, with the associated consequence of the conversion of liquid transportation fuels to lower value gaseous hydrocarbons, i.e., loss of liquid transportation fuel yield. Thus, hydrocracking of the feedstock is performed on fractions boiling above the desired product range to minimize this yield loss.

[0037] When the objective of hydroprocessing is traditional hydrocracking to reduce molecular weight and boiling point, the feedstock led to the process is fractionated to contain a minimum boiling point below the desired end point to minimize the loss of liquid product yield. However, when the objective is the conversion of cyclic molecules to branched molecules with the associated effect of shifting the aromatics to non-aromatic cyclic molecular equilibrium away from aromatic molecules, in contrast to the objective of reducing molecular weight by traditional hydrocracking, the stream led to hydroconversion instead has a boiling point distribution with a wide overlap with the desired products. Although a certain amount of the stream may boil at a higher temperature to compensate for the inevitable reduction in molecular weight, in order to have a substantial conversion of cyclic molecules to non-cyclic molecules, the stream for hydroconversion must contain a fraction that overlaps with the desired product boiling point range. The addition of hydrogen to the hydrocarbonaceous cyclic molecules has the additional advantage of increasing the molecular weight and decreasing the density, so that the volume increases by two mechanisms.

[0038] It is desirable to upgrade the middle distillate fraction of hydrotreated pyrolysis oil to meet diesel and aviation fuel standards or at least provide a product suitable for blending with the above products. Moreover, the properties of the fraction boiling in the naphtha range do not meet the requirements for use in gasoline. For this fraction, the density also exceeds the required level, and furthermore, as a result of the aromatic character, the concentration of benzene is too high. However, while ring opening of the middle distillate boiling range product improves the cetane number, the removal of cyclic molecules in the naphtha typically reduces the octane number and therefore the value of the product, therefore the naphtha fraction of the product can typically be advantageously removed from the middle distillate fraction before hydroconversion in order to maximize the value and volume of this naphtha fraction. The naphtha fraction also has several possible uses, for example as a gasoline fraction, as a source of aromatics; benzene, toluene and xylenes, as a paraffin naphtha for use in steam crackers after hydroconversion, or finally as a naphtha fraction and light gases, which may also be directed for use in hydrogen production, in which case the costs of fractionation prior to hydroconversion cannot be justified.

[0039] The hydroprocessed stream, which contains hydrocarbons, excess hydrogen, and inorganic molecules containing heteroatoms, must be separated into hydrocarbons and molecules containing heteroatoms, which are typically in gaseous form. To do this, the hydroprocessed stream is led to a separation section, which for a process scenario for the treatment of pyrolysis oil is typically either between a base metal-based hydrotreating reactor and a precious metal-based hydroconversion reactor, or downstream of the hydroconversion reactor if the hydroconversion catalyst contains a base metal. The method may also include one or more other conversion steps, such as hydroconversion or hydroisomerization, and depending on the sequence of these steps and the catalytically active metals used, the skilled person will recognize possible positions for introducing a separation section for the purpose of taking off a recycle gas stream.

[0040] In the process of processing oxygen-rich feedstock, heat generation and hydrogen consumption are large, so the gas-oil ratio in the hydroprocessing reactor is also very high compared to other hydroprocessing processes, for example, 1000-7000 Nm 3 / m 3 This hydrogen gas can be used to control the process temperature by stepwise injection of cooled gas. Typically, the gas-to-oil ratio is selected from the hydrogen concentration in the process gas and the expected consumption of hydrogen, calculated from the molecular composition of the feedstock, including the average number of double and aromatic bonds, heteroatoms, and the expected breakage of carbon-carbon bonds, multiplied by a safety factor that can be 2 to 10 times depending on the nature of the process, including the risk of process runaway.

[0041] The pyrolysis oil product stream may contain aromatic hydrocarbons, long-chain linear hydrocarbons, gaseous hydrocarbons, water, and some carbon oxides. In addition, nitrogen and chlorides in the hydrocarbonaceous feedstock result in ammonia and hydrogen chloride in the hydroprocessed stream; these may solidify as ammonium chloride. The added sulfur as well as any sulfur in the pyrolysis oil will be present in the hydroprocessed stream as hydrogen sulfide, and ultimately the excess hydrogen will be sent to the hydroprocessed stream unreacted. Intermediate separation steps may be required for optimal handling of this diverse mixture, so that "sour gas" containing H2S, CO2, and NH3 is removed prior to these reactions, especially when some process steps are carried out using catalysts containing precious metals.

[0042] Furthermore, the need to combine three or four catalysts for optimal conversion of pyrolysis oil to hydrocarbons naturally complicates the process layout and the sequence of materials must be carefully considered, especially with regard to the presence of sulfur, which is required for base metals and should be avoided for precious metals.

[0043] In the process layout, recycle can be for various purposes: gas recycle for efficient use of hydrogen, liquid recycle around the hydroconversion catalyst to maximize the yield of the desired fraction, and liquid recycle around the hydrotreating catalyst to limit the temperature rise due to exothermic deoxygenation reactions and to limit the reaction rate of polymerization reactions involving reactive oxygenates and other reactive compounds in the pyrolysis oil. The choice of recycle configuration is associated with various advantages, including process simplicity by minimizing the number of recycle loops, minimizing reactor volume and cost by choosing a configuration with a small recycle volume, maximizing process reactivity control by large recycle volume and / or large-scale cooling, and minimizing polymerization by large recycle volumes.

[0044] Process configurations without recycle can also be beneficial because of their simplicity and low cost, especially where process volumes are moderate or where suitable diluents are available. [Brief description of the drawings]

[0045] Description of the drawings FIG. 1 shows a process for converting solid materials into transportation fuels. Solid feedstock (2), such as used tires or wood waste (straw, wood or similar), is led to a hydrothermal cracking plant (PYP), which can be of several different types. In the figure, solids (4), such as char and carbon black, pyrolysis gas (6) and pyrolysis oil (8) are discharged from the hydrothermal cracking plant (PYP), although not all fractions may be present. Generally, pyrolysis oil is only formed after cooling the gas phase from the pyrolysis process. In addition to the pyrolysis oil, water can also be condensed from the gas phase. Integrated into the pyrolysis process, hydrotreating can also be carried out, in which the pyrolysis steam or pyrolysis oil is contacted with hydrogen in the presence of a hydrotreating catalyst, for example in a process in which the catalyst is fluidized. To provide a hydrotreated intermediate, a hydrotreating (HDT) step is carried out after combining the hydrogen-rich stream (10) with the pyrolysis oil (8) in the presence of a hydrotreating catalyst (HDT) comprising one or more metals (typically sulfided base metals, but occasionally noble metals) on a refractory support, such as alumina. Here, this step is shown as a single fixed bed reactor (HDT), but in practice this step may include multiple reactors, local recycling of intermediate products, splitting of feedstock between multiple other known variations, such as from the processing of renewable oils and / or fossil feedstocks.

[0046] The hydrotreated intermediate (12) is directed to a first fractionation step (FRAC1) where gas (14), naphtha (16), diesel (17) and high boiling hydrotreated hydrocarbons (18) are separated, and the diesel (17) and high boiling hydrotreated hydrocarbons (18) are combined with the recycled heavy ends (20) as a stream for hydroconversion (22) for further hydroprocessing in a hydroconversion reactor (HC) where it is contacted with a hydroconversion catalyst comprising an active metal (which can be either a sulfided base metal or a precious metal) and an acidic support, such as a zeolite. Hydroconversion produces a hydroconverted hydrocarbon stream (24) by saturating aromatic compounds and breaking carbon-carbon bonds and opening hydrocarbon rings, with the side effect of reducing the molecular weight by breaking some molecules. Thus, the amount of cyclic compounds is reduced, the amount of middle distillates such as jet and diesel, and the boiling range of the hydroconverted hydrocarbon stream (24) changes, along with the naphtha and fuel gas feed that is separated in the second fractionation step (FRAC2) into gas (26), naphtha (28), diesel (30) and recycled heavy products (20). The naphtha (28) produced during hydroconversion is paraffinic and therefore has a lower octane number, and therefore may be preferably directed to a hydrogen plant to provide hydrogen for the process. Since the high boiling hydrotreated hydrocarbons (18) have been fractionated to include a certain amount of material boiling above the middle distillate boiling range, a certain amount of such heavy products is likely to be present for recycle to the inlet of the hydroconversion reactor.

[0047] FIG. 1 has been created to illustrate the principles of the process and, for simplicity, details including heat exchangers, gas loops and phase separators have been omitted.

[0048] In an alternative embodiment, the entire hydrotreated intermediate (12) can be combined with the recycle heavy ends (20) and conducted as stream (24) for hydroconversion.

[0049] Description of the Preferred Embodiments There are multiple aspects of the disclosed invention.

[0050] A first aspect of the present disclosure relates to a process for producing a hydrocarbon composition useful as a transportation fuel in accordance with commercial transportation fuel specifications from a hydrocarbonaceous feedstock containing at least 0.5 wt. % oxygen and at least 25 wt. % carbon in cyclic structures, the process comprising the steps of: a. subjecting a hydrocarbonaceous feedstock to hydroprocessing in one or more steps to provide an intermediate product containing less than 0.1 wt. % oxygen and, for fractions boiling in the range established by said commercial transportation fuel specifications, a specific gravity exceeding the upper specific gravity limit of said commercial transportation fuel specifications; b. providing, from said intermediate product, optionally by fractionation, a hydrotreated hydrocarbon stream for hydroconversion, said fraction for hydroconversion being in accordance with the T 100% commercial transportation fuel specification; 95 Less than T 50 4. The method of claim 3, c. directing said hydroconversion stream into contact with a hydroconversion catalyst under hydroconversion conditions to provide a hydroconverted hydrocarbon stream; d. Fractionating said hydroconverted hydrocarbon stream to provide at least said hydrocarbon composition useful as a transportation fuel.

[0051] This has the related advantage of providing a cost-effective method for producing transportation fuels from cyclic aromatic feedstocks.

[0052] The fractionation of the hydroconverted hydrocarbon stream further comprises: 95 wherein said fraction is directed as recycle to be combined with the hydrotreated hydrocarbon stream for said hydroconversion.

[0053] This has the related advantage of also converting high boiling feedstocks into transportation fuels.

[0054] A third embodiment of the process according to the first or second embodiment, wherein the hydroconversion conditions comprise a pressure greater than 15 MPa and less than 25 MPa.

[0055] This has the associated advantage of elevated pressure which favors the addition of hydrogen to saturate aromatic compounds and open cyclic structures.

[0056] A fourth embodiment of the process according to any of the above embodiments, wherein the hydroconversion conditions comprise a temperature greater than 350° C. and less than 420° C.

[0057] This has the associated advantage of providing stringent conditions that support high reactivity.

[0058] A fifth embodiment of the process according to any of the above embodiments, wherein the hydroconversion catalyst comprises an active metal, either one or more elemental precious metals such as platinum and / or palladium, or one or more sulfide base metals such as nickel, cobalt, tungsten, or molybdenum, an acidic support, such as molecular sieves that exhibit high activity in breaking carbon-carbon bonds and have topologies such as MFI, BEA, and FAU, or amorphous silica-alumina, and optionally a refractory support, such as alumina, silica, or titania, or a combination thereof.

[0059] This has the associated advantage of making such materials active in hydroconversion reactions in which carbon-carbon bonds are broken and molecular structure is altered.

[0060] A sixth embodiment of the process according to any of the above embodiments, wherein at least one step of hydrotreating is carried out outside of a fixed bed reactor.

[0061] This has the related advantage of allowing the hydrotreating process to be closely coupled with the upstream thermochemical conversion process.

[0062] A seventh embodiment of the method according to any of the above embodiments, wherein the commercial transportation fuel standard is a diesel standard, such as European standard EN590.

[0063] This has the associated advantage that diesel fuel has a large boiling range overlap with feedstocks derived from thermochemical conversion.

[0064] An eighth embodiment of the process according to any of the above embodiments, wherein providing a hydrotreated hydrocarbon stream for hydroconversion from the intermediate product by fractionation comprises separating the intermediate product into a fraction boiling in the naphtha range and a fraction boiling above the naphtha range.

[0065] This has the associated advantage of making it possible to avoid hydroconversion of the fraction boiling in the naphtha range, which would reduce the octane number of this fraction.

[0066] A ninth embodiment of the process according to any of the above embodiments, wherein the hydrocarbonaceous feedstock is derived from a thermochemical cracking process.

[0067] This has the related advantage of enabling the upgrading of such hydrocarbonaceous feedstocks from thermochemical cracking processes, which is particularly useful when the feedstock contains large amounts of cyclic structures from materials that have been subjected to a thermochemical cracking process, such as is the case from used tires and wood materials.

[0068] A further aspect of the invention relates to a process plant for producing hydrocarbons by a method according to any of the above aspects. EXAMPLES

[0069] example The process shown in FIG. 1 is evaluated based on experiments in combination with process simulation evaluations.

[0070] Case 1, shown in Table 1, corresponds to a process layout according to Figure 1, but for simplicity, the heavy product 20 is taken off instead of recycling it. Here, the pyrolysis oil (stream 8) derived from the pyrolysis of used tires is hydrotreated, separated into naphtha and high boiling fractions and contacted with a hydroconversion catalyst under conditions leading to a diesel product containing low amounts of aromatics and a specific gravity value according to the EN590 requirements (0.8391 instead of the stated 0.845). The severity of the conditions is shown by the conversion of the fraction boiling above 390°C, of ​​which 73.5 wt% is converted to lower boiling products.

[0071] Stream 16 is a fraction of aromatic naphtha corresponding to 15 wt% FF (wt% on a fresh feed basis). Additionally, 16 wt% FF naphtha containing 8.3 wt% aromatics is produced in stream 28, and 62 wt% FF diesel containing 4.0 wt% aromatics is produced in stream 30. Additionally, 6.1 wt% FF is available as unconverted oil, which can be directed as recycle.

[0072] Case 2, shown in Table 2, corresponds similarly to a variant of the process layout according to FIG. 1, but in which the entire hydrotreated product 12 is led to hydrocracking. The severity of the conditions is shown by the conversion of the fraction boiling above 390° C.: in this case, 56.5% by weight is converted to lower boiling products. For practical reasons, experiments were carried out in which only the liquid fraction of the hydrotreated product 12 was led to hydrocracking.

[0073] Here, 66 wt% FF diesel was produced, which has a specific gravity slightly above the EN590 requirements (0.8468 versus the stated 0.845). Even if slightly more severe conditions were chosen, the diesel yield was expected to be about 64 wt% FF, i.e., slightly above that shown in Table 1.

[0074] For naphtha, only 24 wt. % FF was produced, containing 13 wt. % aromatics, which is about half the amount, a low aromatics content.

[0075] Finally, Case 3 shown in Table 3 represents a situation where intermediate fractionation results in naphtha and diesel, and hydroconversion is carried out as hydrocracking to maximize liquid yield. This case shows a total of 76.5 wt.% diesel and 18.1 wt.% naphtha, which is a slightly higher combined yield of products boiling in the diesel and naphtha ranges compared to Cases 1 or 2, but the 62 wt.% FF diesel product does not meet the gravity specification, thus introducing a limitation on its use, even in blends.

[0076] Taken together, the above results show that for Case 1, hydroconversion of fractions boiling within and above the diesel range results in diesel fractions according to gravity requirements. Additionally, two naphtha streams are provided, one with high aromatics content (and therefore high octane number) and one with low aromatics content.

[0077] For Case 2, the quantity and quality of the diesel fraction exceeds that of Case 1, but only a single naphtha fraction is provided, which has a lower aromatics content and is less in quantity than that of Case 1.

[0078] For Case 3, it can be seen that although more diesel and naphtha can be obtained, the diesel fraction has a very low specific gravity value and therefore has limited value as a diesel blendstock. Furthermore, the density almost 4% above specification also results in a 4% lower volume for the same mass, so the loss in mass is to some extent compensated for by the increase in volume.

[0079] [Table 1]

[0080]

Table 2

[0081]

Table 3

Claims

1. 1. A process for producing a hydrocarbon composition useful as a transportation fuel in accordance with commercial transportation fuel specifications from a hydrocarbonaceous feedstock containing at least 0.5% by weight oxygen and at least 25% by weight carbon in cyclic structures, comprising the steps of: a. subjecting a hydrocarbonaceous feedstock to hydroprocessing in one or more steps to provide an intermediate product containing less than 0.1 wt. % oxygen and, for fractions boiling in the range established by said commercial transportation fuel specifications, a specific gravity that exceeds the upper specific gravity limit of said commercial transportation fuel specifications; b. Providing, optionally by fractionation, from said intermediate product a hydrotreated hydrocarbon stream for hydroconversion, said fraction for hydroconversion meeting or exceeding the T of said commercial transportation fuel specifications. ９５ Less than T ５０ 4. The method of claim 3, c) directing the hydroconversion stream into contact with a hydroconversion catalyst under hydroconversion conditions to provide a hydroconverted hydrocarbon stream; d. fractionating said hydroconverted hydrocarbon stream to provide at least said hydrocarbon composition useful as a transportation fuel; The method includes:

2. The fractionation of the hydroconverted hydrocarbon stream further comprises fractionating the hydroconverted hydrocarbon stream to meet commercial transportation fuel specifications T ９５ 13. The method of claim 1 , further comprising: providing at least one fraction boiling above 1000° C., said fraction being directed as recycle to be combined with the hydrotreated hydrocarbon stream for said hydroconversion.

3. 3. The process of claim 1 or 2, wherein the hydroconversion conditions comprise a pressure greater than 15 MPa and less than 25 MPa.

4. 4. The process of claim 1, 2 or 3, wherein the hydroconversion conditions comprise a temperature greater than 350° C. and less than 420° C.

5. 5. The method of claim 1, 2, 3 or 4, wherein the hydroconversion catalyst comprises an active metal, either one or more elemental precious metals such as platinum and / or palladium, or one or more sulfided base metals such as nickel, cobalt, tungsten or molybdenum, an acidic support, such as molecular sieves that exhibit high activity in breaking carbon-carbon bonds and have topologies such as MFI, BEA and FAU, or amorphous silica-alumina, and optionally a refractory support, such as alumina, silica or titania, or a combination thereof.

6. 6. The process of claim 1, 2, 3, 4 or 5, wherein at least one step of hydrotreating is carried out outside the fixed bed reactor.

7. 7. The method of claim 1, 2, 3, 4, 5 or 6, wherein the commercial transportation fuel specification is a diesel specification, such as European standard EN590.

8. 8. The method of claim 1, 2, 3, 4, 5, 6 or 7, wherein said providing a hydrotreated hydrocarbon stream for hydroconversion from said intermediate product by fractionation comprises separating said intermediate product into a fraction boiling in the naphtha range and a fraction boiling above the naphtha range.

9. 9. The method of claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the hydrocarbonaceous feedstock is derived from a thermochemical cracking process.

10. 10. A process plant for producing hydrocarbons by the method of claim 1, 2, 3, 4, 5, 6, 7, 8 or 9.

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