A method for stabilizing an unstable crude hydrocarbon-containing product

Abstract

A first aspect of the invention relates to a process for producing a stabilized hydrocarbon product from a solid feedstock, comprising the steps of: providing a solid feedstock for thermal decomposition; directing the solid feedstock for thermal decomposition to a thermal decomposition process to provide a thermally decomposed fluid product and a solid phase; directing at least an amount of the thermally decomposed fluid product as a crude feedstock and an amount of hydrogen gas to contact a material catalytically active in the hydrogenation of conjugated diene carbon-carbon bonds under active conditions for the hydrogenation of conjugated diene carbon-carbon bonds, characterized in that the ratio between hydrogen gas and crude feedstock is between 1 Nm 3 / m 3 and 100 Nm 3 / m 3 . This has the associated benefit that the process requires only a small amount of hydrogen gas while still providing a stabilized hydrocarbon product for transport.

Description

Technical Field

[0001] The pyrolysis of solid feedstocks (such as mixed municipal waste, mixed or sorted plastic waste, and forestry waste) provides a liquid product (for simplicity, referred to as pyrolysis oil or crude pyrolysis oil), which can be upgraded to high-quality hydrocarbons and used as transportation fuels or petrochemical feedstocks.

[0002] Pyrolysis is a moderately complex process and can be carried out in equipment that converts a suitable amount of solid feedstock. While transporting solid feedstock in this regard is a significant cost, pyrolysis in medium-sized, decentralized facilities may be convenient, but processing the product (pyrolysis oil) to meet current trade standards requires substantial processing, making it unsuitable for small-scale operations.

[0003] Crude pyrolysis oil—the direct liquid product of most pyrolysis methods—is highly unstable due to its strong tendency to solidify (e.g., through polymerization), and therefore is generally preferred to be upgraded in the same equipment as the pyrolysis process. However, upgrading is more advantageous to be carried out in large-scale hydroprocessing units because process support, including utilities such as hydrogen and steam, is required.

[0004] We further determined that the pyrolysis process can operate in a manner that provides a sufficient amount of H2 to achieve this type of stabilization. The process aspects supporting H2 formation are particularly related to process conditions and configurations that favor the formation of solid elemental carbon.

[0005] To bridge these conflicting needs, we propose an integrated process that includes the decentralized stabilization of crude pyrolysis oil, the transportation of the stabilized pyrolysis oil to a central upgrading and hydrotreating facility, and a cost-effective process for the decentralized production of such stabilized pyrolysis oil using hydrogen from the pyrolysis tail gas.

[0006] definition

[0007] It should be understood that the pressure listed is gauge pressure, which is higher than the ambient pressure.

[0008] The term continuous operation (as is known in the art) refers to the supply of raw materials and the withdrawal of products without interruption during a given production cycle. This contrasts with batch operation (i.e., discontinuous operation), which, as is also well known in the art, involves the introduction of the full amount of liquid oil and catalyst at the start of the process, and the produced products are withdrawn after a period of time.

[0009] It should be understood that the unit Nm 3 This refers to "standard condition" m 3 This refers to the amount of gas that occupies that volume at 0°C and 1 atmosphere.

[0010] As used herein, the terms "hydrogen to liquid oil ratio" or "H2 / oil ratio" refer to the volume ratio of hydrogen to liquid oil flow rates, and are reported in Nm³. 3 / m 3 The gas phase is reported under standard conditions, and the liquid phase is reported under standard conditions (at 25°C and 1 atmosphere).

[0011] Where concentration is expressed in wt%, it should be understood as weight / weight.

[0012] In the following text, "hydrocarbon feedstock" is used to refer to feedstocks rich in molecules containing hydrogen and carbon, but may also contain heteroatoms (i.e., other elements such as oxygen, sulfur, and nitrogen).

[0013] In the following text, olefin concentration should be defined as the total mass of molecules in a mixture having at least one C=C double bond divided by the total mass of hydrocarbon molecules (hydrocarbons, oxygen-containing compounds, and hydrocarbon molecules containing other heteroatoms). A similar definition should apply to the concentrations of other groups of substances characterized by functional groups, such as oxygen-containing compounds or alcohols.

[0014] In the following text, the elemental concentrations, such as carbon, hydrogen, oxygen, and nitrogen, should be the total mass of that element relative to the total mass of all molecules in the composition.

[0015] As used herein, the term "thermal decomposition" should be used broadly for convenience in any decomposition process in which solid material is partially decomposed at elevated temperatures (typically 250°C to 800°C or even 1000°C) in the presence of substoichiometric amounts of O2 (including without added oxygen). The products will typically be a combination of liquid and gaseous streams, along with a certain amount of solid coke. The term should be interpreted to include processes known as pyrolysis and hydrothermal liquefaction, regardless of the presence or absence of a catalyst. For convenience, the products of such thermal decomposition processes may be referred to as pyrolysis oil, but should be understood to encompass any thermal decomposition process.

[0016] As used herein, the term "section" refers to a physical section comprising units or combinations of units for performing one or more steps and / or sub-steps.

[0017] The terms “polymer-derived raw materials” or “waste polymers” can be understood to include mixed classified waste containing at least 50 wt%, 80 wt%, or 90 wt% plastics and other man-made polymers.

[0018] Biologically derived raw materials can be defined by tracing their origin, but they can also be defined by their... 14 The definition is based on the C isotope content being higher than one part per 0.5 trillion of its total carbon content.

[0019] Where hydrogen gas and its concentration are mentioned, they should generally be understood as elemental hydrogen, unless it is implied that hydrogen is part of another molecule.

[0020] Where oxygen content is mentioned, it should generally be understood as atomic oxygen as part of other molecules, unless specifically referring to O2.

[0021] Technical issues

[0022] For example, cost-effective operation of plastic waste pyrolysis equipment typically produces crude pyrolysis oil, which is unsuitable for transportation due to its high reactivity and potential for solidification during transport, especially at moderately elevated temperatures or in the presence of O2. The conversion and stabilization of such reactive materials often require high hydrogen consumption and multiple process steps, thus benefiting from large-scale operation. This contradicts the fact that such equipment is generally preferred for local facilities (with raw material capacity ranging from approximately 10 to 2000 tons / day to minimize the transport of solid raw materials to the equipment). Therefore, it is desirable to establish a decentralized stabilization process and thereby identify a stabilization process suitable for such small-scale intermediates to facilitate their production and storage.

[0023] One challenge in operating such small-scale facilities is the high cost of supplying small quantities of hydrogen, and while pyrolysis tail gas can be converted into hydrogen, the investment in the process equipment for building hydrogen production facilities is more expensive, thus increasing the cost per unit volume of hydrogen. However, if sufficient hydrogen can be provided simply by separating and purifying the hydrogen from the pyrolysis tail gas without chemical conversion, the entire stabilization process can be carried out in a more cost-effective manner, especially considering that the cost of separation equipment is more attractive than that of hydrogen production equipment for small hydrogen volumes.

[0024] Solution to the problem

[0025] The composition of pyrolysis oil varies depending on the solid feedstock and the thermochemical decomposition process, but pyrolysis oil derived from the thermal decomposition of synthetic polymers may involve 0.5–5 wt% conjugated dienes and up to 30–90 wt% olefins, such as 65 wt% olefins. If the feedstock is solid, the atomic oxygen content is typically likely to be less than 1 wt%, but if the solid feedstock contains a large amount of organic material, such as mixed municipal solids, the oxygen atomic content can be as high as 50 wt%.

[0026] Through this invention, crude products of thermochemical decomposition (e.g., pyrolysis oil) can be stabilized with minimal hydrogen consumption, possibly at low pressure and moderate temperature, through the conversion of at least the most reactive compounds in the pyrolysis oil. For polymer-derived feedstocks, such as waste plastics, the most reactive fraction of crude pyrolysis products is typically a hydrocarbon molecule with a conjugated diene structure, including vinyl aromatics and styrene-type structures, where two double bonds or aromatic bonds between carbon atoms are separated by a single bond. These conjugated dienes, especially at temperatures above 50°C and / or in the presence of O2, may polymerize to form larger molecules that may not be liquid under the conditions used during storage, transportation, or processing. Low molecular weight dienes are particularly prone to this polymerization because the conjugated double bonds near the molecular ends are more reactive.

[0027] Similar problems with reactive compounds also exist in biologically derived materials, but here they are carbonyl oxygen-containing compounds such as furfural, furan, aldehydes, ketones and acids, which may polymerize, and pyrolysis oils may often contain molecules with diene structures and carbonyl oxygen molecules at the same time.

[0028] To stabilize these reactive compounds at a moderate cost, we have identified the possibility of providing a limited amount of hydrogen, only in low excess relative to the hydrogenation of the most reactive groups. The amount of hydrogen provided may be only sufficient for the conjugated diene (in the case of oils derived from the thermal decomposition of synthetic polymers, the presence may be 0.5–5 wt%), and we propose limiting conditions (including, but not limited to, temperature, pressure, hydrogen availability, catalyst activity, and space velocity) such that only the reactive groups are converted, and accordingly, the amount of hydrogen can also be limited. For example, the hydrogen-to-liquid-oil ratio may be 4 Nm. 3 / m 3 This value is low enough that hydrogen can dissolve almost completely in the oil. This also has the benefit that reactors and process lines do not need to be designed for gas-liquid contact in two-phase flow.

[0029] Thermochemical decomposition (such as pyrolysis and hydrothermal liquefaction) of plastic waste, biomass, and municipal solids into liquid products, particularly in subsequent hydrotreating, is considered an environmentally friendly source of high-quality petroleum product alternatives, especially from a global warming perspective. Due to the nature of these liquid products (referred to as pyrolysis oils for simplicity, regardless of their origin from any particular thermochemical decomposition process), they require upgrading, such as removing heteroatoms (e.g., sulfur and oxygen) and hydrogenating olefin structures through hydrotreating. The very nature of the formation means the products are unstable and therefore, unlike typical fossil feedstocks, can be highly reactive, requiring large amounts of hydrogen, releasing significant amounts of heat during the reaction, and exhibiting a high tendency to polymerize. The heat release can further promote polymerization, and at elevated temperatures, catalysts can also deactivate due to coking.

[0030] The process plant section for the thermochemical decomposition of hydrocarbon feedstocks provided in this disclosure can take various forms, including converters, fluidized beds, conveyor beds, or circulating fluidized beds, as is known in the art. This decomposition converts the pyrolysis feedstock into solids (coke), high-boiling-point liquids (tar), and gaseous fractions at elevated temperatures. The gaseous fractions include condensable fractions (pyrolysis oil or condensate, C5+ compounds) at standard temperatures and non-condensable fractions (pyrolysis gas, including pyrolysis tail gas). For example, the thermochemical decomposition process plant section (pyrolysis section) may include a pyrolysis unit (pyrolysis reactor), a cyclone separator and / or filter (to remove particulate solids such as coke), and a cooling unit, thereby generating a pyrolysis tail gas stream and the pyrolysis oil stream, i.e., condensed pyrolysis oil. The pyrolysis gas stream contains light hydrocarbons, such as C1-C4 hydrocarbons, and typically also contains H2O, CO, and CO2. Generally, the term pyrolysis oil includes condensate and tar, and pyrolysis oil streams from biomass pyrolysis may also be referred to as bio-oil or bio-crude oil. Pyrolysis oil is a liquid substance rich in molecular mixtures, typically composed of over two hundred different compounds, primarily oxygen-containing compounds such as acids, sugars, alcohols, phenols, guaiacol, eugenol, aldehydes, ketones, furans, and other mixed oxygen-containing compounds, which are produced by the depolymerization of solids during pyrolysis. Unless O2 is added during the decomposition process, the thermochemical decomposition of non-biological waste containing suitable components (such as plastic parts or rubber, including waste tires) will generally only provide products with low oxygen content and will typically provide hydrocarbon-containing feedstocks that reflect the structure of the solid pyrolysis feedstock. Broadly speaking, the elemental composition of pyrolysis oil produced from biomass solid feedstocks is: 3 wt% to 50 wt% oxygen and 50 wt% to 85 wt% carbon. In a broad sense, the elemental composition of pyrolysis oil produced from waste plastics will contain relatively low levels of oxygen, such as 500 wt ppm, 0.5 wt% to 5 wt%, or 10 wt%, and the composition will have a high concentration of conjugated dienes, such as 1 gl / 100g, 5 gl / 100g to 10 gl / 100g, or 25 gl / 100g. The diene values ​​of the liquid stream can be derived using the standard ASTM UOP-326.

[0031] For the purposes of this invention, the pyrolysis stage can be rapid pyrolysis, also known in the field as flash pyrolysis. Rapid pyrolysis is the thermochemical decomposition of a solid feedstock typically in the absence of O2, at a temperature range of 350-650°C (e.g., about 500°C), and a reaction time of 10 seconds or less (e.g., 5 seconds or less, e.g., about 2 seconds). Rapid pyrolysis can be carried out, for example, by autothermal operation (e.g., in a fluidized bed reactor). The latter, also known as autothermal pyrolysis, is characterized by the use of air (optionally with an inert gas or a recirculated gas) as the fluidizing gas. Thus, the partial oxidation of the pyrolysis compounds produced in the pyrolysis reactor (autothermal reactor) provides energy for the pyrolysis while improving heat transfer. In so-called catalytic rapid pyrolysis, a catalyst can be used. Acid catalysts (typically containing zeolites and without active metals) can be used to upgrade the pyrolysis steam, which can be operated either in situ (with the catalyst located in the pyrolysis reactor) or out-of-situ (with the catalyst placed in a separate reactor). The advantage of using a catalyst is that it helps stabilize the pyrolysis oil, making it easier to hydrotreate. Furthermore, it can improve the selectivity for desired pyrolysis oil compounds.

[0032] In some cases, hydrogen is added to catalytic pyrolysis, which is called reactive catalytic fast pyrolysis. If catalytic pyrolysis is carried out at high hydrogen pressures (e.g., above 0.5 MPa), it is generally called catalytic hydrogenation pyrolysis. Catalysts used for upgrading in the presence of hydrogen typically contain one or more metals with hydrogenation activity, such as metals from Group 6 or Groups 8, 9, or 10.

[0033] The pyrolysis stage may be rapid pyrolysis, carried out in the absence of a catalyst and hydrogen; that is, the rapid pyrolysis stage is not catalytic rapid pyrolysis, hydrogenation pyrolysis, or catalytic hydrogenation pyrolysis. This can greatly simplify the process and reduce costs.

[0034] In one implementation, thermal decomposition is hydrothermal liquefaction. Hydrothermal liquefaction refers to the thermochemical conversion of solid feedstocks (e.g., plastic waste, biomass, municipal solid waste, or sewage sludge) into liquid fuels by breaking down the solid biopolymer structure into predominantly liquid components through treatment in a high-temperature, high-pressure aqueous environment for a sufficient time. Typical hydrothermal treatment conditions are temperatures in the range of 200–500°C (particularly 300–450°C) and operating pressures in the range of 4–40 MPa (particularly 25–35 MPa). Compared to pyrolysis (e.g., rapid pyrolysis), this technology offers advantages such as lower operating temperatures, higher energy efficiency, and lower tar yield.

[0035] In one embodiment, pyrolysis further includes passing the solid feedstock through a solid feedstock preparation section, which includes, for example, drying to remove moisture and / or pulverizing to reduce particle size. Any moisture / humidity evaporated in the solid feedstock during, for example, the pyrolysis section, will condense in the pyrolysis oil stream and be carried away in the process, which may be undesirable. Furthermore, the heat used for water evaporation removes the heat originally necessary for pyrolysis. By removing moisture and reducing the particle size of the solid feedstock, the thermal efficiency of the pyrolysis section is improved.

[0036] Finally, other related thermochemical decomposition methods are medium- or slow pyrolysis, which involves lower temperatures and typically longer residence times—these methods may also be referred to as carbonization or torrefaction. The main advantage of these thermochemical decomposition methods is lower investment, but they may also have specific advantages depending on the requirements of certain feedstocks or products (e.g., the need for biochar as a byproduct), and are also relevant to this disclosure because a high hydrogen content is expected in the pyrolysis tail gas.

[0037] When a large amount of solid products are generated, such as in the process of producing biochar, or when it is necessary to recover unconverted carbon black particles from the thermochemical conversion of waste tires, it may be beneficial to filter liquid products as part of the thermochemical conversion process, which will also have the benefit of minimizing the deactivation of downstream catalysts.

[0038] The hydrogenation of reactive compounds is exothermic in terms of the chemistry of the process. This means that as long as the temperature is sufficient to ignite the hydrogenation reaction of the most reactive compounds, a temperature rise will occur to ensure further reaction of other compounds, but by limiting the availability of hydrogen, the temperature rise will not proceed to the level where hydrocarbons would be converted into solid carbon deposits, thereby deactivating the catalyst.

[0039] As previously mentioned, macromolecules are generally less reactive than small molecules. Therefore, sufficient stabilization for transport can be achieved by directing only the lightest and least stable fractions of the pyrolysis products for stabilization, while minimizing local process volume and hydrogen consumption. In practice, such fractionation can be achieved by fractionating products with a wide boiling point range in a fractionator, or by condensing high-boiling fractions at, for example, 250°C, while the less stable low-boiling fractions are either hydrogenated in the vapor state or condensed before hydrogenation.

[0040] Therefore, we propose a process for hydrotreating a liquid oil stream by reacting it with hydrogen in a continuous operation in the presence of a hydrotreating catalyst with moderate sulfur resistance. The catalyst can be a sulfide catalyst comprising one or more of nickel, cobalt, molybdenum, and tungsten, typically operating at an inlet temperature of 130–200°C; or it can be a metal catalyst comprising one or more of nickel, palladium, and platinum, typically operating at an inlet temperature of 80–130°C. In most cases, the pressure is 0.5–2 MPa, but can be up to 35 MPa, and the liquid hourly space velocity (LHSV) is 0.1–5 h⁻¹. -1 These conditions enable the formation of a stable liquid oil flow.

[0041] The process is moderately exothermic, so a temperature rise of 5-20°C typically occurs.

[0042] According to the present invention, a continuous operation process is employed because, unlike batch operation, there is no dependence on the fluidity of the resulting product (stabilized liquid oil) at any given time. This process can be carried out, in particular, in fixed-bed reactors, slurry-bed reactors, trickle-bed reactors, and fluidized-bed reactors.

[0043] Providing hydrogen for hydrotreating is a significant cost, and reducing hydrogen demand could be a driver of cost reduction. In hydrotreating, a certain amount of hydrogen is consumed per unit volume of oil; this is known as the hydrogen-to-oil consumption ratio. Depending on the properties of the crude product, for complete hydrotreating, the hydrogen-to-oil consumption ratio can be as low as 50 Nm. 3 / m 3 Up to 1000 Nm 3 / m 3 However, to minimize the risk of coke deposition and coking on the catalyst, a safety factor of 2, 4, or even 8 is typically used, making the 200 Nm 3 / m 3 The hydrogen-to-oil consumption ratio will result in a hydrogen-to-oil ratio as high as 1000 Nm 3 / m 3 The hydrogen-to-oil consumption ratio is higher in this process—while if the purity of the hydrogen-rich gas in the process is only 80 vol%, the resulting gas-to-oil ratio will be 500 Nm. 3 / m 3 Such an excess of gas would naturally lead to an increase in equipment size, and an excess of H2 could also lead to increased reactivity, causing the actual H2 consumption to rise simply because of its availability.

[0044] With such high hydrogen levels, recirculating gas becomes economically viable, and the associated costs and scale of equipment (such as recirculating gas compressors) necessitate increased throughput.

[0045] The demand for high excess H2 is primarily related to elevated temperatures and near-complete hydrogenation. Therefore, we propose limiting H2 to less than the amount required for complete hydrogenation, as this prevents thermal runaway and limits hydrogen consumption, thereby reducing operating costs, process volume, and capital investment, since recirculation and recirculation compressors are not required.

[0046] As mentioned above, the thermal decomposition of solid materials can be carried out under a wide range of process conditions. Typically, these conditions are adjusted to maximize the yield of liquid products and optimize their processing performance.

[0047] Bajad, GS, Journal of Analytical and Applied Pyrolysis (2017), (http: / / dx.doi.org / 10.1016 / j.jaap.2017.04.016) studied the production of liquid hydrocarbons, carbon nanotubes, and hydrogen-rich gas from waste plastics, reporting oil yields of 5–45 wt%, solid yields of 10–20 wt%, and gas yields of 45–75 wt%, with H2 at 10–23 vol%. Similarly, F. Ate (Bioresource Technology, 133 (2013) 443–454 (https: / / doi.org / 10.1016 / j.biortech.2013.01.112)) reported yields of 52 wt% and 35 wt% oil, 33 wt% and 55 wt% solids, and 10 wt% and 15 wt% gas from the pyrolysis of municipal plastic waste at 550°C and 600°C, with H2 content of 2.7–4 vol%; similarly, oil yields from the pyrolysis of municipal solid waste were 9 wt% and 30 wt%, solid yields were 37 wt% and 20 wt%, and gas yields were 20 wt% and 23 wt%, with H2 content of 1.2–1.4 vol%. The relative yields of the waste plastic examples were converted to Nm³. 3 / m 3 The calculated H2 availability is 3.4 Nm. 3 / m 3 Up to 130 Nm 3 / m 3 For mixed municipal solid waste, a similar value is 5 Nm³. 3 / m 3 Up to 12 Nm 3 / m 3 .

[0048] For hydrogen to function effectively in the hydrotreating process, it should preferably be available at pressures of 0.5 MPa, 2 MPa, or 5 MPa and a purity of at least 80 vol%. Such hydrogen streams can be obtained through various methods. One method is to pressurize the entire stream and then purify it using a gas membrane, or alternatively, to purify the gas using pressure swing adsorption (PSA). These purification processes are preferably operated at pressures above 2 MPa up to 5 MPa and are capable of purifying hydrogen to a purity of at least 99 vol%. If PSA purification is used, it may be more cost-effective to moderately pressurize upstream of the PSA unit and ultimately pressurize a smaller stream of purified hydrogen to the hydrotreating conditions.

[0049] The process may further include subjecting the stabilized pyrolysis oil stream to further hydrotreating steps, possibly after transport to a central site where the stabilized pyrolysis oil can be further processed to produce hydrocarbons suitable for conversion in a steam cracking unit, or to produce products that boil within the range of transport fuels, such as diesel, jet fuel, and naphtha. Further processing may include hydrodewaxing, hydrocracking, or isomerization, as is known in the fossil petroleum refining industry.

[0050] Materials exhibiting catalytic activity, particularly in the initial hydrogenation treatment of conjugated double bonds (e.g., hydrogenation), typically comprise an active metal (a base metal sulfide, such as nickel, cobalt, tungsten, and / or molybdenum, but may also be elemental metals, including nickel and noble metals such as platinum and / or palladium) and a refractory support (such as alumina, silica, or titanium dioxide, or combinations thereof). Initial hydrogenation treatment conditions can involve moderate temperatures in the range of 120–200 °C and moderate pressures in the range of 0.5–5 MPa, as well as liquid hourly space velocities (LHSV) in the range of 0.1–5. For some conditions, increased pressures up to 35 MPa may be required.

[0051] In one embodiment, the catalyst is in the form of a sulfide, such as NiMoS or CoMoS. The catalyst can be pre-sulfurized by exposure to a sulfur-containing stream, or it can be sulfided in situ (i.e. during operation), for example by sulfur present in the pyrolysis oil, so that the sulfidation catalyst remains in a sulfidated state and thus remains active due to the presence of sulfur.

[0052] Final hydrotreating (e.g., hydrogenation) conditions typically involve higher temperatures in the range of 250–400°C, higher pressures in the range of 3–15 MPa, and liquid hourly space velocity (LHSV) in the range of 0.1–4, optionally combined with intercooling by quenching with cold hydrogen, feed, or product.

[0053] Materials that are catalytically active in isomerization typically include active metals (elemental noble metals such as platinum and / or palladium, or base metals such as nickel, cobalt, tungsten, and / or molybdenum), acidic supports (typically molecular sieves exhibiting high shape selectivity and having topologies such as MOR, FER, MRE, MWW, AEL, TON, and MTT), and refractory supports (such as alumina, silica, or titanium dioxide, or combinations thereof).

[0054] The isomerization conditions involve a temperature range of 250–400°C, a pressure range of 2–10 MPa, and a liquid hourly space velocity (LHSV) range of 0.5–8.

[0055] Materials exhibiting catalytic activity in hydrocracking are similar in properties to those exhibiting catalytic activity in isomerization, and typically comprise an active metal (elemental noble metals such as platinum and / or palladium, or base metals such as nickel, cobalt, tungsten, and / or molybdenum), an acidic support (usually molecular sieves exhibiting high cracking activity and possessing topologies such as MFI, BEA, and FAU), and a refractory support (such as alumina, silica, or titanium dioxide, or combinations thereof). The difference from materials exhibiting catalytic activity in isomerization usually lies in the nature of the acidic support, which may have a different structure (even amorphous silica-alumina) or different acidity, for example, due to the silica / alumina ratio.

[0056] Hydrocracking conditions can involve temperatures in the range of 250–400°C, pressures in the range of 3–20 MPa, and liquid hourly space velocity (LHSV) in the range of 0.5–8, optionally combined with intercooling by quenching with cold hydrogen, feed, or product.

[0057] Other types of hydrotreating have also been envisioned, such as hydrodearomatization (HDA). Catalytically active materials in HDA typically comprise an active metal (usually a noble elemental metal such as platinum and / or palladium, but also potentially a base metal sulfide such as nickel, cobalt, tungsten, and / or molybdenum) and a refractory support (e.g., amorphous silica-alumina, alumina, silica, or titanium dioxide, or combinations thereof).

[0058] The conditions for hydrodearomatization involve a temperature range of 200–350°C, a pressure range of 2–10 MPa, and a liquid hourly space velocity (LHSV) range of 0.5–8.

[0059] Any embodiment of the first aspect of the invention and its related benefits may be used in conjunction with the second aspect of the invention, and vice versa.

[0060] Beyond concerns about purification and pressurization, optimizing the operating conditions of the pyrolysis process to produce the optimal amount of hydrogen may also be beneficial. Optimization may focus on designing a process that yields a balanced output of hydrogen and pyrolysis oil, potentially involving overall process and equipment design in addition to operational optimization. However, for variations in feedstocks, temperature and space velocity can be further optimized and balanced, typically achieved through lower temperatures and lower space velocities (longer residence times) that favor the production of hydrogen and elemental carbon.

[0061] Process optimization may aim to maximize hydrogen production, but another optimization objective may be to balance the amount of hydrogen produced with the amount required for stabilizing the pyrolysis oil. Additionally, selecting pyrolysis conditions that will produce increased amounts of carbon solids (such as stabilized coke, carbon nanotubes, or carbon black) may also be an option. The value of this carbon black can then be estimated either based on trade value or the financial value of carbon sequestration of non-reactive carbon. This optimization can be performed automatically during operation via appropriate control loops, where process control intervals are 0.1–10 times the process time constant, or at appropriately longer intervals. These intervals can be time-based or event-based, such as changes in feedstock, changes in production setpoint, the amount of feedstock processed, the commercial value of product combinations, deviations from the setpoint in process operation, and changes in catalyst activity and process equipment. In the case of event-based optimization, this can be implemented as electronic feedback for controlling specific process parameters, or it can be implemented by providing information to the process operator to change process variables, such as by providing deviation notifications or by calculating one or more suggested operating scenarios.

[0062] Beneficial effects of the invention

[0063] A first aspect of the invention relates to a method for producing stabilized hydrocarbon-containing products from a solid feedstock, the method comprising the steps of: providing a solid feedstock for thermal decomposition; directing the solid feedstock for thermal decomposition to a thermal decomposition process to provide thermal decomposition fluid products and a solid phase; separating the fluid products into a low-boiling fraction comprising a gas phase boiling below 30°C and a high-boiling fraction comprising a liquid phase boiling above 100°C; and directing the low-boiling fraction to a separation device configured to provide a hydrogen-rich fraction (containing at least 80... The crude liquid feedstock consists of at least a certain amount of the thermal decomposition fluid product and a certain amount of hydrogen (containing a certain amount of the hydrogen-rich fraction) and the remaining low-boiling fraction; the thermal decomposition fluid product and the remaining low-boiling fraction are directed to a catalytic process to contact a material catalytically active in the hydrogenation of conjugated diene carbon-carbon bonds under active conditions for the hydrogenation of conjugated diene carbon-carbon bonds, to provide the stabilized hydrocarbon-containing product, wherein the catalytic process may have several catalytically distinct steps, and wherein the crude liquid feedstock and hydrogen are added together or separately at one or more locations, and the stabilized hydrocarbon-containing product is withdrawn for transport or storage, optionally after the removal of the aqueous phase or other impurities, characterized in that the ratio of the total amount of hydrogen added to the amount of crude liquid feedstock is 1 Nm. 3 / m 3 Up to 100 Nm 3 / m 3 .

[0064] The relevant benefit is that the process requires only a small amount of hydrogen while still providing stabilized hydrocarbon products for transportation or storage.

[0065] A second aspect of the invention relates to a method in which the separation device includes a gas membrane separator or a pressure swing absorption unit.

[0066] The associated benefits are that gas membrane separators are inexpensive devices, with their price proportional to the volume of gas being separated. The associated benefits of pressure swing absorption units are also moderate cost (proportional to the volume of gas being processed) and the very high purity achievable through this separation method.

[0067] A third aspect of the invention relates to the method according to the first aspect, characterized in that the ratio of the total amount of hydrogen added to the amount of crude liquid feedstock is from 1, 2, 5 or 10 Nm. 3 / m 3 Up to 20 Nm 3 / m 3 or 50 Nm 3 / m 3 .

[0068] The relevant benefit of this is that this amount of hydrogen corresponds to the amount of reactive compounds in the thermal decomposition fluid products.

[0069] A fourth aspect of the invention relates to the method according to the first or second aspect, wherein at least 50% of the total amount of hydrogen added is provided by the hydrogen-rich fraction.

[0070] The fifth aspect of the invention relates to a method according to any of the preceding aspects, wherein the solid raw material comprises at least 50% waste polymer.

[0071] The relevant benefit is that the process is well-suited for processing waste polymer feedstocks for use in steam cracking units with stabilized products, optionally after further processing.

[0072] A sixth aspect of the invention relates to a method according to any of the foregoing aspects, further relating to separating the thermal decomposition fluid products into at least a polar liquid phase and a nonpolar liquid phase.

[0073] The related benefit is that it can provide a feedstock suitable for processing feedstocks containing high levels of oxygen that can be converted into water, such as feedstocks containing a large amount of biological sources.

[0074] The seventh aspect of the invention relates to a method according to any of the above aspects, wherein the active hydrogenation conditions involve pressures ranging from ambient pressure or 0.5 MPa to 10 MPa, 20 MPa or 35 MPa.

[0075] The relevant benefit of this is that it reduces equipment costs without negatively impacting performance, since pressure has no limit on hydrogen solubility.

[0076] The eighth aspect of the invention relates to a method according to any of the above aspects, wherein the active hydrogenation conditions involve an inlet temperature from 80 to 210°C.

[0077] The relevant benefit of this is that it provides sufficient temperature for process initiation while maintaining a low temperature so that only the most reactive compounds are converted.

[0078] The ninth aspect of the invention relates to a method according to any of the preceding aspects, wherein the material having catalytic activity in hydrogenation comprises at least one of Ni, Co, Mo, W, and Pd.

[0079] The tenth aspect of the invention relates to a method according to any of the preceding aspects, wherein the hydrogen is provided at least in part by the reaction of a certain amount of the fluid products of the thermal decomposition product stream, optionally using electric heating.

[0080] The relevant benefit is that the waste gas from the pyrolysis stream is converted into process hydrogen with minimal CO2 emissions, especially if the electricity is generated from excess process heat or from renewable energy sources such as solar, wind, or wave energy.

[0081] The eleventh aspect of the invention relates to a method according to any of the preceding aspects, wherein the hydrogen is generated at least in part by electrolysis, optionally using electricity generated from excess process heat or from renewable energy sources such as solar, wind, or wave energy.

[0082] The relevant benefit of this is that it converts the waste gas from the pyrolysis stream into process hydrogen with minimal CO2 emissions.

[0083] The twelfth aspect of the invention relates to a method according to any of the above aspects, wherein the thermal decomposition products are cooled to a temperature between 20°C and 150°C, 180°C or 230°C before contact with a material having catalytic activity in the hydrogenation process.

[0084] The relevant benefit of this is that it avoids curing due to polymerization.

[0085] The thirteenth aspect of the invention relates to a method according to any of the above aspects, wherein the amount of solid raw material is at least 10 tons / day or 50 tons / day, and less than 2,000 tons / day, less than 1,000 tons / day or less than 500 tons / day.

[0086] The relevant benefit is that this scale of process is well-suited for decentralized stabilization but too small for optimal operation to achieve full conversion.

[0087] The fourteenth aspect of the invention relates to a method according to any of the preceding claims, comprising the further steps of: monitoring a chemical characteristic of a hydrocarbon-containing product having a limit value indicating stability; monitoring the amount of hydrogen in the gas phase; adjusting one or more process conditions to increase the amount of hydrogen in the gas phase if the chemical characteristic indicates lower than desired stability; and adjusting the one or more process conditions to decrease the amount of hydrogen in the gas phase if the chemical characteristic indicates higher than desired stability.

[0088] The relevant benefit of this is that it provides automatic adjustment of process conditions to produce optimal amounts of stabilized hydrocarbon-containing products. Such processes may include other criteria for adjusting process parameters, including monetary values ​​and costs, as well as environmental indicators of value or cost associated with the process and products.

[0089] The fifteenth aspect of the invention relates to a method according to any of the foregoing aspects, wherein a stabilized hydrocarbon-containing product is transferred to a transport device (e.g., a storage tank or pipeline) and transported to a upgrading facility for upgrading to produce a final hydrocarbon product.

[0090] The relevant benefit is that this process is well-suited for centralized processing aimed at producing hydrocarbon products for steam cracking or as part of transportation fuel.

[0091] Other aspects involve process equipment, including means for performing any of the foregoing aspects, wherein the means are configured accordingly. Attached Figure Description

[0092] Figure 1 A thermochemical decomposition method is shown, in which all liquid hydrocarbon products are stabilized by hydrogenation.

[0093] Figure 2 A thermochemical decomposition method was shown, in which only light hydrocarbons were stabilized by hydrogenation.

[0094] Figure 1

[0095] exist Figure 1 In this process, solid feedstock (102) is directed to a thermochemical decomposition reactor (PYR). Thermochemical decomposition produces three streams: a high-temperature gas stream (104), solid char (106), and liquid pyrolysis oil (108). Thermochemical decomposition processes may have internal recirculation or additional inlets, such as for gases, water, and solvents, but these are generally not included in the process. Figure 1 Not shown in the diagram. The high-temperature gas flow (104) is directed to a hydrogen separation unit (HSU), which includes a hydrogen compressor (HCP) and a gas separation unit (GS), which may be a membrane separator, a pressure swing adsorption unit, or a similar technology. The gas separation unit (GS) separates the gas into tail gas (110) and hydrogen-rich gas (112). The hydrogen-rich gas (112) is optionally combined with a certain amount of supplemental hydrogen (114), which may be derived from any hydrogen source, including compressed hydrogen and hydrogen produced by electrolysis.

[0096] The full-scale pyrolysis oil (108) is combined with a suitable amount of hydrogen (116) and optionally heated, either by heating a single stream or by heating a combined crude feed stream (122). The crude feed stream is directed into a hydrotreatment reactor (HYD) to contact with a material that is catalytically active in hydrotreatment, at a moderate temperature (such as 150°C) and a moderate pressure (such as 2 MPa). The hydrotreatment reactor (HYD) is shown as a stand-alone unit, but it can also be integrated into a thermochemical decomposition reactor (PYR).

[0097] The product stream (124) will typically be directed to a gas-liquid product separator (SEP) to separate the light gas (126) from the stabilized hydrocarbon product (130); and if the crude product contains oxygen, the product separator can be a three-way separator, since the liquid will contain both hydrocarbon and aqueous phases. In the diagram, the separator (SEP) is a reboiling stripper, which has the benefit of removing dissolved hydrogen and other gases from the product.

[0098] A stable hydrocarbon phase will have sufficient stability for transportation and storage, but its quality is insufficient for use as a transportation fuel or a feedstock for chemical processes such as steam cracking.

[0099] If the process involves a significant excess of hydrogen, it makes economic sense to recover this hydrogen through gas recycling, although such a recycling loop involves capital and operating costs. If the excess hydrogen is small, the gas can be directed to thermochemical decomposition and used as a heat source.

[0100] Figure 2

[0101] exist Figure 2 In this process, a solid feedstock (202) is directed to a thermochemical decomposition reactor (PYR). Thermochemical decomposition is shown as producing two streams; a solid char (206) and a fluid stream (208). Thermochemical decomposition processes may have internal recirculation or additional inlets, such as gases, water, and solvents, but these are not always present in the PYR process. Figure 2 It is not displayed.

[0102] In this figure, the fluid stream (208) is fractionated into a high-temperature gas stream (204), a light-range pyrolysis oil (210), and a heavy-range pyrolysis oil (212). The fractionation is shown as taking place in a fractionator, but the process used for pyrolysis oil condensation can also be used for similar fractionation.

[0103] A high-temperature gas stream (204) is directed to a hydrogen separation unit (HSU), which includes (but is not shown) a hydrogen compressor (HCP) and a gas separation unit (GS). The hydrogen separation unit (HSU) releases exhaust gas (210) and hydrogen-rich gas (212). The hydrogen-rich gas (212) is optionally combined with a certain amount of supplemental hydrogen (214), which can be derived from any hydrogen source, including compressed hydrogen and hydrogen produced by electrolysis, to form a hydrogen-rich stream (216).

[0104] A light-range pyrolysis oil (218) is combined with a hydrogen-rich stream (216) and optionally heated, either by heating one of the two streams or by heating the combined crude feed stream (222). The crude feed stream is directed to a hydrotreatment reactor (HYD) for contact with a material catalytically active in hydrotreatment, at a moderate temperature of, for example, 150°C and a moderate pressure of, for example, 2 MPa. The hydrotreatment reactor (HYD) is shown as a stand-alone unit, but it can also be integrated into a thermochemical decomposition reactor (PYR).

[0105] The product stream (224) is typically directed to a gas-liquid product separator (SEP) to separate the light gas (226) from the stable light product (228), and if the crude product contains oxygen, the product separator can be a three-way separator, since the liquid will contain both hydrocarbon and aqueous phases. In the diagram, the separator (SEP) is a reboiling stripper, which has the benefit of removing dissolved hydrogen and other gases from the product.

[0106] The stabilized light product (228) is combined with the heavy range pyrolysis oil (220) to form a stabilized hydrocarbon-containing product (230) which will have sufficient stability for transportation and storage, but not sufficient quality for use as a transportation fuel or feedstock for chemical processes such as steam cracking.

[0107] Figure 3

[0108] exist Figure 3 In this process, the solid feedstock (302) is directed to the thermochemical decomposition reactor (PYR). Thermochemical decomposition produces three streams: a high-temperature gas stream (304), solid char (306), and liquid pyrolysis oil (308). In this example, the high-temperature gas stream (304) may be directed as fuel for heating the pyrolysis process, directed to a flare, or possibly converted into hydrogen in a hydrogen production facility.

[0109] The full-scale pyrolysis oil (308) is combined with a suitable amount of hydrogen (314) and optionally heated, either by heating a single stream or by heating a combined crude feed stream (322). The crude feed stream is directed into a hydrotreatment reactor (HYD) to contact with a material that is catalytically active in hydrotreatment, at a suitable temperature, for example, 150°C, and a suitable pressure, for example, 2 MPa. The hydrotreatment reactor (HYD) is shown as a stand-alone unit, but it can also be integrated into a thermochemical decomposition reactor (PYR).

[0110] The product stream (324) will typically be directed to a gas-liquid product separator (SEP) to separate the light gas (326) from the stabilized hydrocarbon product (328), and if the crude product contains oxygen, the product separator may be a three-way separator, as the liquid will contain both hydrocarbon and aqueous phases. In the diagram, the separator (SEP) is a reboiling stripper, which has the benefit of removing dissolved hydrogen and other gases from the product.

[0111] While the stabilized hydrocarbon phase will have sufficient stability for transport and storage, its quality is insufficient for use as a transport fuel or feedstock for chemical processes such as steam cracking.

[0112] If the process involves a significant excess of hydrogen, it is economically viable to recover this hydrogen through gas recycling, although such a recycling loop involves capital and operating costs. If the excess hydrogen is less, the gas can be directed to thermochemical decomposition for use as a heat source.

[0113] Example

[0114] To illustrate the invention, two examples are given. Tables 1 and 2 show the boiling point curves and the contents of conjugated dienes and olefins in the process of treating the hydrothermal liquefaction products of 1200 tons / day (50 tons / hour) of plastic waste, based on... Figure 1 or Figure 2 One method involves mild hydrogenation. Due to the presence of dienes, the feedstock tends to polymerize and solidify during transport, especially when heated above 50°C. For this example, it is assumed that the availability of hydrogen from the pyrolysis gas is 4 Nm³. 3 / m 3 This is consistent with the data reported in Ate§ 2016 cited above.

[0115] According to Figure 1 In Example 1 reported in Table 1, the full-range pyrolysis oil was guided to a mild hydrotreating process at 150°C, where the amount of hydrogen was equivalent to twice the theoretical hydrogen consumption for diene saturation. This amount is 99% soluble in the oil, thus ensuring good contact and avoiding the practical challenges of large gas flow rates. This is equivalent to 4 Nm 3 / m 3 The hydrogen / oil ratio was adjusted. The amount of conjugated diene was reduced from 1.9 wt% to 0.095 wt%, which will produce a product that is stable during transportation.

[0116] According to Figure 2 In Example 2 reported in Table 2, only the naphtha-range fraction pyrolysis oil was subjected to mild hydrotreating at 150°C, where the amount of hydrogen was equivalent to twice the theoretical hydrogen consumption for diene saturation, which was also substantially dissolved in the oil in this example. This is equivalent to 4 Nm of hydrogen in the hydrotreating stream. 3 / m 3 The hydrogen / oil ratio is [not specified]. The amount of conjugated diene is reduced only from 1.9 wt% to 1.35 wt%, but the most reactive small molecule conjugated diene is reduced by 95%, so the product will have sufficient stability for transport.

[0117] These two examples demonstrate that the supplemental hydrogen required to stabilize pyrolysis oil can be provided by separating hydrogen from the tail gas of the thermochemical decomposition process.

[0118] Table 1

[0119] Table 2

Claims

1. A method for producing stabilized hydrocarbon-containing products from solid raw materials, the method comprising the following steps: (a) Provide solid feedstock for thermal decomposition, (b) The solid feedstock for thermal decomposition is directed to the thermal decomposition process to provide thermal decomposition fluid products and, optionally, a solid phase. (c) Separating the fluid product into a low-boiling fraction consisting of a gas phase boiling below 30°C and a high-boiling fraction consisting of a liquid phase boiling above 100°C. (d) The low-boiling fraction is directed to a separation unit configured to provide a hydrogen-rich fraction containing at least 50 vol%, for example 80 vol%, of hydrogen and the remaining low-boiling fraction. (e) Introducing at least a certain amount of the thermal decomposition fluid product, as a crude liquid feedstock, and a certain amount of hydrogen containing a certain amount of the hydrogen-rich fraction, into a catalytic process to contact a material catalytically active in the hydrogenation of conjugated diene carbon-carbon bonds under active conditions for the hydrogenation of conjugated diene carbon-carbon bonds, thereby providing the stabilized hydrocarbon-containing product, wherein the catalytic process may have several catalytically distinct steps, and wherein the crude liquid feedstock and hydrogen are added together or independently at one or more locations. (f) and, optionally, removing the stabilized hydrocarbon-containing product for transport or storage, after removing the aqueous phase or other impurities. Its characteristic is that the ratio of the total amount of added hydrogen to the amount of crude liquid feedstock is 1 Nm. 3 / m 3 Up to 100 Nm 3 / m 3 .

2. The method according to claim 1, wherein the separation device comprises a gas membrane separator or a pressure swing absorption unit.

3. The method according to claim 1 or 2, wherein the ratio of the total amount of hydrogen added to the amount of crude liquid feedstock is from 1, 2, 5 or 10 Nm. 3 / m 3 Up to 20 Nm 3 / m 3 or 50 Nm 3 / m 3 .

4. The method according to claim 1, 2 or 3, wherein at least 50% of the total amount of hydrogen added, for example 75%, 90% or 100%, comes from the hydrogen-rich fraction.

5. The method according to any of the preceding claims, wherein the solid raw material comprises at least 50% waste polymer.

6. The method according to any of the preceding claims further relates to separating the thermal decomposition fluid products into at least a polar liquid phase and a non-polar liquid phase.

7. The method according to any of the preceding claims, characterized in that, Active hydrogenation conditions involve pressures ranging from 0.5 MPa to 35 MPa.

8. The method according to any of the preceding claims, characterized in that, Active hydrogenation conditions involve inlet temperatures ranging from 80 to 210°C.

9. The method according to any one of the preceding claims, characterized in that, The catalytically active material in hydrogenation includes at least one of Ni, Co, Mo, W, and Pd.

10. The method according to any of the preceding claims, characterized in that, A certain amount of the hydrogen is provided at least in part by the reaction of a certain amount of the thermal decomposition fluid products, optionally using electric heating.

11. The method according to any of the preceding claims, characterized in that, A certain amount of the hydrogen is produced at least partially by electrolysis, optionally using electricity generated from excess process heat or from renewable energy sources such as solar, wind, or wave energy.

12. The method according to any of the preceding claims, wherein the thermal decomposition products are cooled to a temperature between 20°C and 150°C, 180°C or 230°C before contacting the material having catalytic activity in the hydrotreatment.

13. The method according to any of the preceding claims, wherein the amount of solid raw material is at least 10 tons / day or 50 tons / day, and less than 2,000 tons / day, less than 1,000 tons / day, or less than 500 tons / day.

14. The method according to any of the preceding claims, comprising the following further steps: Monitor the chemical characteristics of hydrocarbon-containing products, which have limits indicating stability; Monitor the amount of hydrogen in the gas phase; If the chemical characteristics indicate a lower stability than required, one or more process conditions are adjusted to increase the amount of hydrogen in the gas phase; as well as If the chemical characteristics indicate a higher stability than desired, then the one or more process conditions are adjusted to reduce the amount of hydrogen in the gas phase.

15. A process apparatus configured to perform the method according to any of the preceding claims.

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