Hydrogenation method of waste tire pyrolysis oil

Abstract

This invention relates to the field of petroleum refining and chemical engineering, and discloses a method for hydrogenating waste tire pyrolysis oil. The method includes the following steps: (1) in the presence of hydrogen, the waste tire pyrolysis oil raw material undergoes a gas-phase desulfurization reaction in a first gas-phase hydrogenation reactor to obtain a gas-phase desulfurization reaction product; (2) the gas-phase desulfurization reaction product is subjected to gas-liquid separation to obtain a gas-phase component and a liquid-phase component; (3) the liquid-phase component is pressurized and mixed with hydrogen, and then subjected to a liquid-phase dearomatics reaction in a second hydrogenation reactor to obtain a liquid-phase dearomatics reaction product; the nitrogen content in the waste tire pyrolysis oil raw material is 3000-10000 μg / g. This method uses waste tire pyrolysis oil from the middle distillate as raw material, achieving deep desulfurization while reducing the removal of nitrogen oxides and monocyclic aromatic hydrocarbon saturation. It also simplifies the overall process flow, reduces the reaction severity, and lowers energy and hydrogen consumption.

Description

Technical Field

[0001] This invention relates to the field of oil refining and chemical technology, specifically to a method for hydrogenating waste tire pyrolysis oil. Background Technology

[0002] With my country's increasing emphasis on environmental protection and resource recycling, the processing of waste tire pyrolysis oil has gradually become a hot topic. Waste tire pyrolysis involves decomposing waste tires into pyrolysis gas, pyrolysis oil, and pyrolysis char in a pyrolysis reactor. The pyrolysis oil is rich in sulfides, nitrogen compounds, olefins, alkanes, and aromatics, and its calorific value is similar to that of diesel fuel, making it suitable for producing automotive diesel products via hydrorefining. However, waste tire pyrolysis oil is characterized by a high nitrogen compound content, even approaching its sulfur content. This poses a significant challenge to hydrodesulfurization, as nitrogen compounds severely inhibit the desulfurization reaction; nitrogen compounds must be removed first for effective desulfurization. Furthermore, nitrogen compounds not only significantly inhibit desulfurization and dearomatization reactions but also waste hydrogen resources due to their preferential hydrogenation.

[0003] Furthermore, considering the reaction mechanisms of deep desulfurization and deep aromatics removal, their requirements for the reaction environment differ significantly. For desulfurization reactions, the removal of small-molecule sulfur mainly follows the direct desulfurization route, i.e., hydrodesulfurization. Large-molecule sulfides with lower reactivity mainly follow the hydrodesulfurization reaction route, i.e., first hydrogenation of the aromatic ring, followed by hydrodesulfurization. In the upper part of the reactor, the main processes are the hydrogenation of small-molecule sulfides and nitrides, as well as the conversion of some bicyclic aromatics (exothermic). In the lower part of the reactor, the accumulation of heat and hydrogen sulfide creates a high-temperature, low-hydrogen partial pressure reaction environment, which is unfavorable for the hydrodesulfurization pathway of large-molecule sulfur and the saturation of polycyclic aromatics. Especially towards the end of the reaction, catalyst activity declines; raising the temperature can compensate for the loss of desulfurization activity, but it further affects the aromatics removal efficiency. Besides the different requirements for the reaction environment, the competitive adsorption of aromatics on the catalyst surface also inhibits deep desulfurization, making it difficult for traditional hydrogenation technology to simultaneously meet the dual requirements of ultra-deep desulfurization and efficient aromatics saturation. Furthermore, while diesel fuel is restricted in terms of polycyclic aromatic hydrocarbon (PAH) content, some monocyclic aromatic hydrocarbons undergo hydrogenation saturation during the hydrogenation process, further wasting hydrogen. Based on these two aspects, the necessity and urgency of upgrading diesel fuel to cleaner production technologies become even more apparent.

[0004] Existing technologies for achieving deep dearomatization employ a two-stage process. After conventional hydrogenation, the product oil is stripped to remove hydrogen sulfide before entering a precious metal hydrogenation reactor. This significantly increases catalyst costs and process complexity, and fails to address the hydrogen waste caused by over-hydrogenation. Alternatively, the feedstock can be divided into light and heavy components. The light component undergoes shallow hydrogenation to minimize monocyclic aromatic saturation, while the heavy component undergoes deep hydrogenation for desulfurization and dearomatization. However, shallow hydrogenation typically uses medium-pressure hydrogenation, increasing overall energy consumption and preventing industrial-scale application.

[0005] Patent application CN108085058A discloses a method for deep dearomatization of hydrocarbon oils. This method employs relatively mild temperature and pressure conditions, allowing feedstock oil and hydrogen to pass through a highly dispersed Pt-Pd / Al2O3 catalyst. The resulting gas phase is compressed and recycled, while the liquid phase is a low-aromatic product. However, the Pt-Pd / Al2O3 hydrogenation catalyst is mainly suitable for dearomatization of low-sulfur diesel feedstocks, and its effect on desulfurization and dearomatization of inferior diesel is not ideal.

[0006] Patent application CN109926067A discloses a platinum-palladium-cobalt ternary metal hydrodearomatics catalyst and its preparation method. This method employs a stepwise impregnation process with active metal precursors, resulting in high utilization of the platinum and palladium noble metals in the prepared catalyst, strong synergistic catalytic activity, and enhanced aromatics hydrotreating performance of the non-noble metal cobalt due to the introduction of platinum and palladium. However, this catalyst is still designed for hydrocarbon oils where sulfur compounds have been largely removed, to avoid the influence of hydrogen sulfide on the deep dearomatics removal of noble metals, and cannot achieve desulfurization and dearomatics removal for low-quality diesel fuel. Summary of the Invention

[0007] The purpose of this invention is to overcome the technical problems existing in the prior art and provide a hydrogenation method for waste tire pyrolysis oil. This method uses waste tire pyrolysis oil of the middle distillate as raw material, and while achieving deep desulfurization, it reduces the removal of nitrogen oxides and the saturation of monocyclic aromatic hydrocarbons. At the same time, it simplifies the process flow, reduces the severity of the reaction, and reduces energy consumption and hydrogen consumption.

[0008] To achieve the above objectives, the present invention provides a method for hydrogenating waste tire pyrolysis oil, wherein the method includes the following steps:

[0009] (1) In the presence of hydrogen, waste tire pyrolysis oil raw material is subjected to gas phase desulfurization reaction in the first gas phase hydrogenation reactor to obtain gas phase desulfurization reaction product;

[0010] (2) The gas phase desulfurization reaction products are subjected to gas-liquid separation to obtain gas phase components and liquid phase components;

[0011] (3) The liquid phase component is pressurized and mixed with hydrogen, and then the liquid phase dearomatic reaction is carried out in the second hydrogenation reactor to obtain the liquid phase dearomatic reaction product;

[0012] The nitrogen content in the waste tire pyrolysis oil raw material is 3000-10000 μg / g.

[0013] Compared with the prior art, the method of the present invention has the following advantages:

[0014] The method of this invention avoids the drawbacks of placing deep desulfurization and dearomatization in the same reaction system, where reaction conditions are difficult to reconcile. The inventors have discovered that, in a preferred embodiment, by controlling the reaction conditions of the first hydrogenation reactor, only the hydrogenation removal reaction of sulfides occurs in the first hydrogenation reactor, thereby separating the desulfurization and dearomatization reactions, optimizing the reaction conditions separately, and improving the efficiency of each reaction.

[0015] The method provided by this invention can reduce the hydrogen consumption of the reaction, and also reduce the hydrogen-to-oil volume ratio of the gas-phase hydrogenation reaction, thereby reducing the severity of the reaction.

[0016] The method provided by this invention is particularly suitable for the hydrogenation reaction of waste tire pyrolysis oil with high nitrogen content. While achieving gas-phase desulfurization, the nitrogen compounds are difficult to hydrogenate and enter the gas phase components in large quantities through gas-liquid separation without undergoing deep hydrogenation. This reduces the hydrogen consumption of the chemical reaction, which is more conducive to subsequent deep aromatic removal. For waste tire pyrolysis oil with high nitrogen content, the reduction in hydrogen consumption is even greater.

[0017] The method provided by this invention replenishes the hydrogen consumed in the liquid-phase dearomatics reaction while pressurizing, so that the hydrogen can be used without recycling, eliminating the need for a circulating hydrogen compressor and significantly reducing the investment in equipment construction. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process flow of the present invention.

[0019] Figure Labels

[0020] Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] The description of exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which are considered an integral part of the entire written description. In this specification, relative terms such as “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “upward,” “downward,” “top,” and “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the orientation shown in the accompanying drawings as described at the time. These relative terms are for ease of description and do not require the device to be constructed or operated in a particular orientation. Unless otherwise stated, “connection” as used in this invention refers to a relationship in which structures are directly or indirectly fixed or connected to each other via an intermediate structure.

[0023] In this invention, the symbol “≯” indicates not greater than, and the symbol “≮” indicates not less than.

[0024] This invention provides a method for hydrogenating waste tire pyrolysis oil, wherein the method includes the following steps:

[0025] (1) In the presence of hydrogen, waste tire pyrolysis oil raw material is subjected to gas phase desulfurization reaction in the first hydrogenation reactor to obtain gas phase desulfurization reaction product;

[0026] (2) The gas phase desulfurization reaction products are subjected to gas-liquid separation to obtain gas phase components and liquid phase components;

[0027] (3) The liquid phase component is pressurized and mixed with hydrogen, and then the liquid phase dearomatic reaction is carried out in the second hydrogenation reactor to obtain the liquid phase dearomatic reaction product;

[0028] The nitrogen content in the waste tire pyrolysis oil raw material is 3000-10000 μg / g.

[0029] The method provided by this invention involves a gas-phase desulfurization reaction of waste tire pyrolysis oil feedstock in a first hydrogenation reactor. The gas-phase desulfurization reaction mainly removes small-molecule sulfides but does not remove nitrogen compounds. The liquid phase component obtained by gas-liquid separation of the gas-phase desulfurization reaction product is pressurized and mixed with hydrogen before entering a second hydrogenation reactor for deep hydrogenation dearomatics reaction. The method provided by this invention is applicable to any application requiring the simultaneous removal of small-molecule sulfides and large-molecule aromatics.

[0030] This invention achieves deep desulfurization and dearomatization of feedstock oil under more moderate operating conditions and a simpler process.

[0031] In this invention, the hydrogen gas mentioned in step (1) can be any hydrogen-containing gas capable of providing hydrogen, including fresh hydrogen, recycled hydrogen, and hydrogen-rich gas. Those skilled in the art, after understanding the technical solution of this invention, can clearly understand the hydrogen-containing gas described in this invention.

[0032] In this invention, the waste tire pyrolysis oil refers to the diesel fraction obtained by cutting the pyrolysis oil components from waste tires after a pyrolysis process. This invention does not specifically limit the specific operation methods and means of the pyrolysis process; those skilled in the art can choose according to actual needs.

[0033] In this invention, the range of properties for waste tire pyrolysis oil is relatively wide. Preferably, in step (1), the initial boiling point of the waste tire pyrolysis oil raw material is 130-180℃, the final boiling point is 320-350℃, the S content is ≤15000μg / g, preferably ≤11000μg / g, the N content is 5000-10000μg / g, and the polycyclic aromatic hydrocarbon content is ≤50wt%. For example, the sulfur content of the waste tire pyrolysis oil can be, but is not limited to, 8000 μg / g, 9000 μg / g, 10000 μg / g, 11000 μg / g, etc.; the nitrogen content can be, but is not limited to, 5000 μg / g, 6000 μg / g, 7000 μg / g, 8000 μg / g, 9000 μg / g, 10000 μg / g, etc.; and the polycyclic aromatic hydrocarbon content can be, but is not limited to, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, etc.

[0034] In this invention, preferably, in step (1), based on waste tire pyrolysis oil raw material, the sulfur content in the gas-phase desulfurization reaction product is 1-30 wt%, preferably 4-20 wt%, for example, it can be 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, and any value between any two groups. Since the aromatic rings of macromolecular sulfides cannot be hydrogenated under low pressure conditions, they are more likely to be removed via hydrogen desulfurization, reducing the hydrogen consumption of the chemical reaction. For sterically hindered 4,6-DMDBT-type macromolecular sulfides, they can be deeply removed in subsequent hydrogenation units. In this invention, the sulfur content in the gas-phase desulfurization reaction product is within the above range, exhibiting high hydrogenation selectivity.

[0035] In this invention, the selection range of conditions for the gas-phase desulfurization reaction in the first hydrogenation reactor is relatively wide, as long as the removal of small-molecule sulfur in the gas phase is achieved. Preferably, in step (1), the conditions for the gas-phase desulfurization reaction include: a pressure of 0.5-3 MPa, a temperature of 300-400℃, a hydrogen-to-oil volume ratio of 50-500, and a volume hourly space velocity of 0.5-3 h⁻¹. -1 Further preferably, in step (1), the conditions for the gas-phase desulfurization reaction include: a pressure of 1-2 MPa, a temperature of 320-380 °C, a hydrogen-to-oil volume ratio of 150-300, and a volume hourly space velocity of 1-2 h⁻¹. -1 .

[0036] In this invention, by controlling the reaction conditions of the gas-phase desulfurization reaction, gas-phase desulfurization is achieved while better coordination with the subsequent liquid-phase hydrogenation reaction, thus facilitating further deep aromatic removal. Furthermore, the preferred gas-phase desulfurization reaction conditions of this invention avoid hydrogen saturation of macromolecular nitrides, reducing hydrogen consumption. Macromolecular nitrides often have structures containing aromatic rings and nitrogen heterocycles, and CN-bond breakage only occurs after the aromatic and nitrogen heterocycles are completely hydrogenated. Under the reaction conditions of the gas-phase hydrogenation desulfurization reaction, macromolecular nitrides are difficult to hydrogenate and, through gas-liquid separation, largely enter the gas phase component without undergoing deep hydrogenation, thereby reducing the hydrogen consumption of the chemical reaction.

[0037] In this invention, the first hydrogenation reactor is filled with a hydrogenation catalyst with desulfurization function. This invention does not specifically limit the type of the first hydrogenation catalyst; those skilled in the art can select it according to actual needs. Preferably, in step (1), the gas-phase desulfurization reaction is carried out in the presence of the first hydrogenation catalyst, which includes a support and a hydrogenation component.

[0038] In this invention, the range of types of carriers is relatively wide. Preferably, the carrier is an inorganic refractory oxide, which is selected from at least one of alumina, amorphous aluminum silica, silicon dioxide, and titanium oxide, and more preferably alumina.

[0039] In this invention, the range of hydrogenation components is relatively wide. Preferably, the hydrogenation components include Group VIII metal components and / or Group VIB metal components. In this invention, the specific types of Group VIII and Group VIB metals are not limited, and those skilled in the art can select them according to actual needs.

[0040] In this invention, preferably, the first hydrogenation catalyst is a Mo-Co type hydrodesulfurization catalyst.

[0041] In this invention, there is no particular limitation on the content of each component in the Mo-Co type hydrodesulfurization catalyst. Preferably, based on the total amount of the Mo-Co type hydrodesulfurization catalyst, the content of Mo, calculated as oxide, is 15-30 wt%, and the content of Co, calculated as oxide, is 2-6 wt%.

[0042] In this invention, preferably, the Mo-Co type hydrodesulfurization catalyst further includes an auxiliary component, which is selected from at least one of phosphorus, silicon, boron, magnesium, and fluorine. Preferably, the content of the auxiliary component, calculated as oxides, is 6 wt% or less.

[0043] In this invention, the source of the first hydrogenation catalyst is not limited. For example, it can be prepared by any method conventionally defined in the art, or it can be obtained commercially, such as the FHUDS-5 and / or FHUDS-7 catalysts developed by the Sinopec Fushun Petrochemical Research Institute (FRIPP).

[0044] According to the method provided by the present invention, by matching the use of a high-hydrogen desulfurization pathway catalyst in the first hydrogenation reactor, the desulfurization reaction is controlled to follow a low-hydrogen-consumption reaction pathway more closely, thereby reducing the chemical hydrogen consumption of the desulfurization reaction. At the same time, the hydrogen-to-oil volume ratio of the first hydrogenation reactor can also be reduced, thus reducing the severity of the reaction.

[0045] This invention utilizes a small amount of heat exchange at high temperature on the gas-phase desulfurization reaction products, retaining a large amount of reaction heat while ensuring the liquefaction of macromolecules, thus meeting the feed conditions for the second hydrogenation reactor and saving energy. Preferably, this method further includes cooling the gas-phase desulfurization reaction products through heat exchange before the gas-liquid separation.

[0046] The invention does not impose any particular limitations on the heat exchange conditions, but preferably, conditions that ensure the liquefaction of large molecular weight heavy substances in the gas-phase desulfurization reaction products are preferred. The invention also does not impose any particular limitations on the specific operation of the heat exchange; any heat exchange medium conventionally used in the art can be employed. The heat exchange can be carried out in a heat exchange unit, such as a heat exchanger. The invention does not impose any particular limitations on the specific type of heat exchanger; for example, it can be a commercially available heat exchanger conventionally defined in the art, or a tubular heat exchanger.

[0047] In this invention, preferably, the mass percentage of the liquid phase component is 20-40%, based on the total amount of the gas-phase desulfurization reaction products. This preferred embodiment is more conducive to precisely controlling the liquefaction ratio, selectively hydrogenating heavy components, and reducing chemical hydrogen consumption.

[0048] In this invention, the liquid-phase hydrogenation reactor is filled with a hydrogenation catalyst that has a dearomatics removal function. The range of types of hydrogenation dearomatics catalysts that can be selected in this invention is relatively wide. Preferably, in step (3), the liquid-phase dearomatics removal reaction is carried out in the presence of a hydrogenation dearomatics catalyst, which is a non-precious metal catalyst and / or a precious metal catalyst.

[0049] In this invention, the non-precious metal catalyst may include a support and a hydrogenation active metal, wherein the support is an inorganic refractory oxide, generally selected from at least one of alumina, amorphous aluminum silicate, silica, and titanium dioxide, preferably alumina; the hydrogenation active metal includes a Group VIB metal component and / or a Group VIII metal component. Preferably, in the hydrodearomatization catalyst, the Group VIB metal component is preferably selected from tungsten and / or molybdenum, and the Group VIII metal component is preferably selected from nickel and / or cobalt; preferably, the hydrodearomatization catalyst may also contain an auxiliary component, such as at least one of phosphorus, silicon, boron, magnesium, and fluorine, with a mass content generally below 6 wt% in the hydrodearomatization catalyst. Preferably, the non-precious metal catalyst is a Mo-Ni type hydrodearomatization catalyst.

[0050] In this invention, preferably, based on the total amount of Mo-Ni type hydrodearomatic catalyst, the content of Mo, calculated as oxide, is 15-30 wt%, and the content of Ni, calculated as oxide, is 2-5 wt%.

[0051] In this invention, the source of the hydrodearomatic catalyst is not particularly limited. For example, it can be prepared by any method or obtained commercially. For example, it can be at least one of FHUDS-10, FHUDS-6 and FHUDS-8 developed by Sinopec Fushun Petrochemical Research Institute (FRIPP).

[0052] In this invention, the precious metal catalyst preferably uses Pt, Pd, etc. as the active metal. It can be prepared by any method or it can be a commercially available catalyst, such as the FHDA-10 catalyst developed by the Sinopec Fushun Petrochemical Research Institute (FRIPP).

[0053] In this invention, the selection range of conditions for the liquid-phase dearomatization reaction is relatively wide. Preferably, in step (3), the conditions for the liquid-phase dearomatization reaction include: a pressure of 2-8 MPa, a temperature of 200-400 °C, and a volume hourly space velocity of 0.2-5 h⁻¹. -1 Further preferably, in step (3), the conditions for the liquid-phase dearomatic reaction include: a pressure of 3-6 MPa, a temperature of 260-345 °C, and a volume hourly space velocity of 0.2-0.5 h⁻¹. -1 .

[0054] In this invention, the specific operation and conditions for pressurizing and mixing the liquid phase component in step (3) have a wide range. The pressurization and mixing are used to supplement the hydrogen required for the reaction based on the pressurization of the liquid phase component. Preferably, the pressurization and mixing are performed to meet the reaction conditions and hydrogen consumption requirements in the liquid phase hydrogenation reactor. In this invention, there are no particular limitations on the specific operation of pressurization and mixing. A specific process can be that the liquid phase component is first pressurized by the pressurization unit, and then enters the mixing unit. Hydrogen is pressurized by the compressor (pressurization unit) to a pressure slightly higher than that of the liquid phase component (0.05-0.1 MPa higher), and also enters the mixing unit. The material flowing out of the mixing unit is the liquid phase component with dissolved hydrogen.

[0055] In this invention, the pressurization and hydrogen mixing in step (3) can be carried out in any unit that can achieve pressurization and hydrogen mixing. For example, pressurization and hydrogen mixing can be carried out in a pressurization unit and a hydrogen mixing unit, respectively. There is no particular limitation on the type of pressurization unit and hydrogen mixing unit, as long as the pressurization and hydrogen mixing of the liquid phase components can be achieved.

[0056] In this invention, preferably, the pressurization unit is a gas-phase pressurizer.

[0057] In this invention, preferably, the hydrogen mixing unit is selected from at least one of membrane tube hydrogen dissolving components, hydrogen mixers (e.g., high-efficiency hydrogen mixers), microbubble generators, and bubble fractors. For example, a hydrogen mixer with strong convection backmixing or a hydrogen mixer that generates microbubbles through microchannels is used to increase solubility. Preferably, the hydrogen mixer is provided with a support disk with uniformly distributed pores and downcomers to improve gas phase dispersion.

[0058] In this invention, preferably, in step (3) during the hydrogen mixing process, relative to 1m 3 The liquid phase component has a hydrogen replenishment amount of 10-40 Nm. 3 More preferably 20-30 Nm 3 .

[0059] In this invention, preferably, the pressure of the liquid-phase dearomatic reaction is at least 1 MPa higher than the pressure of the gas-phase desulfurization reaction, and more preferably 2-5 MPa higher. The method provided by this invention carries out the reaction at low pressure, which greatly reduces the severity of the reaction and saves energy.

[0060] In this invention, preferably, the temperature of the liquid-phase dearomatic reaction is at least 15°C lower than the temperature of the gas-phase desulfurization reaction, and more preferably 20-40°C lower. The method provided by this invention is more advantageous for liquefying large molecules that require further reaction while retaining the heat of reaction.

[0061] In this invention, there are no particular limitations on the application of the gaseous component (also known as the hydrogenated light component) and the liquid-phase hydrogenation reaction product obtained by gas-liquid separation; they can be adapted to the specific needs of the product. Preferably, the method further includes mixing the gaseous component and the liquid-phase dearomatization reaction product from step (2) and then performing desulfurization treatment. The gaseous component and the liquid-phase dearomatization reaction product can be processed separately or together, preferably together. According to a preferred embodiment of the invention, the method further includes mixing the gaseous component and the liquid-phase dearomatization reaction product from step (2) and then performing desulfurization treatment to obtain waste tire pyrolysis oil product. This invention does not particularly limit the specific operation and conditions of the desulfurization treatment; it can be carried out according to conventional techniques in the art, preferably stripping. The stripping can be carried out in a stripping unit, such as a stripping tower.

[0062] In this invention, preferably, the aromatic hydrocarbon content in the waste tire pyrolysis oil product is less than 5 wt%, and the sulfur content is less than 10 μg / g.

[0063] In this invention, there is no particular limitation on the types of the first hydrogenation reactor and the second hydrogenation reactor. Preferably, the first hydrogenation reactor and the second hydrogenation reactor are each independently a fixed-bed reactor.

[0064] According to a specific embodiment of the present invention, the aforementioned method of the present invention is carried out as follows: Figure 1 The system shown in the diagram operates as follows: waste tire pyrolysis oil raw material and hydrogen 1 enter the first hydrogenation reactor 2 for gas-phase desulfurization reaction to obtain gas-phase desulfurization reaction product 3. Gas-phase desulfurization reaction product 3 enters the heat exchange unit 4, and after being cooled by heat exchange, it enters the gas-liquid separation unit 5 for gas-liquid separation to obtain gas phase component 7 and liquid phase component 6. Liquid phase component 6 is pressurized by the pressurization and hydrogen mixing unit 8 and then enters the second hydrogenation reactor 9 for liquid-phase dearomatization reaction to obtain liquid-phase dearomatization reaction product 10. Gas phase component 7 and liquid-phase dearomatization reaction product 10 are mixed and then subjected to stripping unit 11. After stripping, waste tire pyrolysis oil product 12 is obtained.

[0065] The present invention will be described in detail below through embodiments.

[0066] In the following examples and comparative examples, chemical hydrogen consumption refers to the percentage of hydrogen mass consumed per unit mass of raw material.

[0067]

[0068] In this invention, unless otherwise explicitly stated, percentages and percentage contents are all expressed by mass.

[0069] The following is combined Figure 1The method and system of the present invention are described in detail below. Waste tire pyrolysis oil feedstock and hydrogen 1 enter the first hydrogenation reactor 2, where a gas-phase desulfurization reaction occurs, yielding a gas-phase desulfurization reaction product 3. This product then enters a heat exchange unit 4 (heat exchanger), where it is cooled before entering a gas-liquid separation unit 5 (gas-liquid separator) to obtain a liquid phase component 6 and a gas phase component 7. Gas phase component 7 is discharged upwards from the gas-liquid separator, while liquid phase component 6 is discharged downwards. After passing through a pressurization and hydrogen mixing unit 8, the product enters the second hydrogenation reactor 9 for a liquid-phase hydrogenation reaction, yielding a liquid-phase dearomatization reaction product 10. Gas phase component 7 and the liquid-phase dearomatization reaction product 10 are mixed and then enter a stripping unit 11 (stripping tower), ultimately yielding the waste tire pyrolysis oil product 12.

[0070] Examples 1-3

[0071] Adopting such Figure 1 The process flow diagram is shown below. Two 100mL fixed-bed hydrogenation reactors are connected in series, designated as the first and second hydrogenation reactors. A heat exchanger, gas-liquid separator, booster, and hydrogen mixer are installed between the reactors. The first hydrogenation reactor is loaded with 50mL of Mo-Co type hydrogenation catalyst A, and the second hydrogenation reactor is loaded with 50mL of Mo-Ni type hydrogenation catalyst B. A gas phase outlet is located above the gas-liquid separator, which connects to the bottom effluent of the second hydrogenation reactor, and both flow into a stripping tower to obtain the waste tire pyrolysis oil product.

[0072] Waste tire pyrolysis oil from the middle distillate fraction was used as feedstock. Catalyst properties are shown in Table 1, feedstock oil properties are shown in Table 2, and reaction process conditions and results are shown in Table 3.

[0073] Example 4

[0074] The same process flow as in Examples 1-3 was used, except that the gas-liquid separation conditions were changed. Catalyst properties are shown in Table 1, feedstock properties are shown in Table 2, and reaction process conditions and results are shown in Table 3.

[0075] Comparative Example 1

[0076] A conventional diesel fixed-bed hydrotreating process was adopted, with two hydrotreating reactors connected in series: the first hydrotreating reactor and the second hydrotreating reactor. A stripping tower was installed between the two reactors to remove hydrogen sulfide. The first hydrotreating reactor was loaded with 50 mL of Mo-Co type hydrotreating catalyst A, and the second hydrotreating reactor was loaded with 50 mL of Mo-Ni type hydrotreating catalyst B. After the reactors, conventional processes such as high-precision separation, low-precision separation, and stripping were followed to obtain waste tire pyrolysis oil. Hydrogen gas, after hydrogen sulfide removal, was pressurized and recycled using a circulating hydrogen compressor. The properties of the raw materials and catalysts were the same as in Examples 1-3, and the reaction process conditions and results are shown in Table 3.

[0077] Comparative Example 2

[0078] The same process flow as in Examples 1-3 was adopted, with the only difference being the increase in the hydrogen-to-oil volume ratio at the inlet of the first hydrogenation reactor, the elimination of the hydrogen mixer before the second hydrogenation reactor, and the use of only a liquid-phase booster pump. The first hydrogenation reactor was loaded with 50 mL of Mo-Co type hydrogenation catalyst A, and the second hydrogenation reactor was loaded with 50 mL of Mo-Ni type hydrogenation catalyst B. The properties of the raw materials and catalysts were the same as in Examples 1-3, and the reaction process conditions and results are shown in Table 3.

[0079] Table 1

[0080]

[0081] Table 2

[0082]

[0083] Table 3

[0084]

[0085] Note: In Table 3, the hydrogen replenishment amount refers to the amount relative to 1m. 3 The amount of hydrogen required to supplement the liquid phase components.

[0086] As shown in Table 3, Comparative Example 1, using conventional fixed-bed hydrogenation technology and a traditional catalyst loading system, suffers from high pressure in the first hydrogenation reactor. This leads to simultaneous and mutually influential desulfurization, denitrification, and dearomatization, making it impossible to optimize reaction conditions for any specific reaction. Consequently, the reaction results are poor, hydrogen consumption is high, hydrogen is recycled, and energy consumption is high. In contrast, the reaction system of this invention, with a significantly reduced pressure in the first hydrogenation reactor, separates desulfurization, dearomatization, and denitrification into two separate reaction systems, allowing for targeted optimization of reaction conditions. This results in better dearomatization, better preservation of nitrogen compounds that do not require hydrogenation, avoiding the limitation of nitrogen compounds on the hydrogenation reaction, and improving reaction efficiency. Sulfides are removed through hydrogenolysis, and nitrogen compounds are hydrogenated in small amounts, reducing hydrogen consumption. Hydrogen does not need to be recycled, further reducing energy consumption.

[0087] In Comparative Example 2, no hydrogen mixer was installed before the liquid-phase reactor. Sufficient hydrogen source was provided by increasing the hydrogen-to-oil volume ratio at the inlet of the first hydrogenation reactor. However, the high hydrogen-to-oil volume ratio in the first hydrogenation reactor resulted in low oil phase partial pressure in the separator, leading to insufficient liquefaction. This meant that polycyclic aromatic hydrocarbons (PAHs) could not fully enter the liquid phase components for liquid-phase hydrogenation, resulting in a higher PAH content in the refined oil. In addition, hydrogen circulation required the use of a compressor, and the energy consumption was still higher than in the example.

[0088] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for hydrogenating waste tire pyrolysis oil, characterized in that, The method includes the following steps: (1) In the presence of hydrogen, waste tire pyrolysis oil raw material is subjected to gas phase desulfurization reaction in the first hydrogenation reactor to obtain gas phase desulfurization reaction product; (2) The gas phase desulfurization reaction products are subjected to gas-liquid separation to obtain gas phase components and liquid phase components; (3) The liquid phase component is pressurized and mixed with hydrogen, and then the liquid phase dearomatic reaction is carried out in the second hydrogenation reactor to obtain the liquid phase dearomatic reaction product; The nitrogen content in the waste tire pyrolysis oil raw material is 3000-10000 μg / g; In step (1), the conditions for the gas-phase desulfurization reaction include: a pressure of 1-2 MPa, a temperature of 320-380℃, a hydrogen-to-oil volume ratio of 150-220, and a volume hourly space velocity of 1-2 h⁻¹. -1 ; In step (3), the conditions for the liquid-phase dearomatic reaction include: a pressure of 3-6 MPa, a temperature of 260-345 °C, and a volume hourly space velocity of 0.2-0.5 h⁻¹. -1 ; The temperature of the liquid-phase dearomatization reaction is at least 15°C lower than the temperature of the gas-phase desulfurization reaction. The method also includes mixing the gas phase component described in step (2) with the liquid phase dearomatic reaction product and then performing desulfurization treatment to obtain waste tire pyrolysis oil product.

2. The method according to claim 1, wherein, In step (1), the initial boiling point of the waste tire pyrolysis oil raw material is 130-180℃, the final boiling point is 320-350℃, the S content is ≯15000μg / g, the N content is 5000-10000μg / g, and the polycyclic aromatic hydrocarbon content is ≯50wt%.

3. The method according to claim 2, wherein, The sulfur content in the waste tire pyrolysis oil raw material is ≤11000μg / g.

4. The method according to claim 1 or 2, wherein, In step (1), the gas-phase desulfurization reaction is carried out in the presence of a first hydrogenation catalyst, which includes a support and a hydrogenation component.

5. The method according to claim 4, wherein, The support for the first hydrogenation catalyst is an inorganic refractory oxide, which is selected from at least one of alumina, amorphous aluminum silica, silicon dioxide, and titanium dioxide.

6. The method according to claim 5, wherein, The hydrogenation component of the first hydrogenation catalyst includes a Group VIII metal component and / or a Group VIB metal component.

7. The method according to claim 6, wherein, The first hydrogenation catalyst is a Mo-Co type hydrodesulfurization catalyst.

8. The method according to claim 7, wherein, Based on the total amount of Mo-Co type hydrodesulfurization catalyst, the content of Mo in oxides is 15-30 wt%, and the content of Co in oxides is 2-6 wt%.

9. The method according to claim 1 or 2, wherein, The method also includes cooling the gas-phase desulfurization reaction products by heat exchange before performing the gas-liquid separation.

10. The method according to claim 9, wherein, Based on the total amount of the gas-phase desulfurization reaction products, the mass percentage of the liquid phase component is 20-40%.

11. The method according to claim 1 or 2, wherein, In step (3), the liquid-phase dearomatic reaction is carried out in the presence of a second hydrogenation catalyst, which is a non-precious metal catalyst and / or a precious metal catalyst.

12. The method according to claim 11, wherein, The second hydrogenation catalyst is a Mo-Ni type hydrogenation dearomatic catalyst.

13. The method according to claim 12, wherein, Based on the total amount of Mo-Ni type hydrodearomatic catalyst, the content of Mo, calculated as oxide, is 15-30 wt%, and the content of Ni, calculated as oxide, is 2-5 wt%.

14. The method according to claim 1 or 2, wherein, In step (3) during hydrogen mixing, relative to 1m 3 The liquid phase component has a hydrogen replenishment amount of 10-40 Nm. 3 .

15. The method according to claim 14, wherein, In step (3) during hydrogen mixing, relative to 1m 3 The liquid phase component has a hydrogen replenishment amount of 20-30 Nm. 3 .

16. The method according to claim 1 or 2, wherein, The temperature of the liquid-phase dearomatic reaction is 20-40°C lower than that of the gas-phase desulfurization reaction.

17. The method according to claim 1 or 2, wherein, The aromatic hydrocarbon content in the waste tire pyrolysis oil product is less than 5 wt%, and the sulfur content is less than 10 μg / g.

18. The method according to claim 1 or 2, wherein, The first hydrogenation reactor and the second hydrogenation reactor are each independently a fixed-bed reactor.

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