Method for preparing clean fuel oil by hydrogenating tire distillation oil

Abstract

This application provides a method for hydrogenating tire retort oil to produce clean fuel oil, relating to the chemical industry. The method comprises: filtering the tire retort oil, mixing it with hydrogen, and then subjecting it to a first heat exchange reaction before entering a pre-hydrogenation reactor for a pre-hydrogenation reaction; heating the product of the pre-hydrogenation reaction before entering a main hydrogenation reactor for a main hydrogenation reaction; and subjecting the product of the main hydrogenation reaction to a second heat exchange reaction, cooling it, and separating it through a high-pressure separator and a low-pressure separator to produce fuel oil. The method for hydrogenating tire retort oil to produce clean fuel oil provided in this application achieves a product whose key performance indicators meet the requirements for clean fuel oil.

Description

Technical Field

[0001] The present application relates to the field of chemical industry, and in particular to a method for preparing clean fuel oil by hydrogenating tire distillation oil. Background Art

[0002] Tire oil is a liquid product obtained by oxygen-free, high-temperature dry distillation of waste tires. Compared to natural petroleum, tire oil has higher contents of olefins, diolefins, and heterocyclic aromatic hydrocarbons, and produces a high amount of carbon dust during the dry distillation process. These unfavorable elements in tire oil hinder its direct use as a transportation fuel. The presence of nitrogen in tire oil reduces fuel stability and storage issues, and also leads to increased nitrogen emissions during combustion. Most of the nitrogen in tire oil is in the form of aromatic compounds. Tire oil also contains high levels of sulfur, which is released as SOx during combustion, making it an undesirable component. Therefore, the production of transportation fuel from tire oil requires the removal of sulfur and nitrogen, as well as the reduction of the aromatic hydrocarbon content.

[0003] Hydrotreating is a general term for the catalytic upgrading of oil products under hydrogen pressure. It involves the hydrogenolysis of non-hydrocarbon components containing sulfur, nitrogen, and oxygen in petroleum fractions and organometallic compounds in the presence of a catalyst and hydrogen, removing sulfur, nitrogen, oxygen, and metals. Olefins and aromatics undergo hydrogenation to saturate them. The products are low-sulfur and low-nitrogen oils, as well as H2S and NH3. All of these reactions consume chemical hydrogen and are exothermic. The main reactions in the hydrotreating of petroleum fractions include: the hydrodecomposition of non-hydrocarbons such as sulfur-, nitrogen-, and oxygen-containing compounds; the hydrogenation and saturation of olefins and aromatics (primarily condensed-ring aromatics); and minor ring-opening, chain-scission, and condensation reactions. These reactions typically involve a series of parallel, sequential reactions, forming a complex reaction network. The depth and rate of the reactions often depend on the chemical composition of the feedstock, the catalyst, and the process conditions. Generally speaking, hydrogenation of nitrogen compounds is the most difficult and requires the most stringent conditions. While nitrogen removal is essential, desulfurization and deoxygenation requirements can also be met.

[0004] The existing hydrogenation process is that the raw oil is filtered, pressurized by a high-pressure feed pump, mixed with fresh hydrogen and recycled hydrogen, and then enters the raw material / hydrogenation product heat exchanger. After heat exchange to a certain temperature, it enters the hydrogenation reaction heating furnace and is heated to a certain reaction temperature, generally 330°C to 420°C. It then enters the hydrogenation reactor and undergoes a series of reactions from top to bottom through the catalyst bed, including olefin saturation, hydrodesulfurization, hydrodenitrogenation, aromatic saturation, and hydrodeoxygenation. This method is suitable for natural petroleum distillates and high-quality raw oils.

[0005] In US4342641, under a certain pressure and a certain space velocity, the full fraction of tire oil enters the first reactor at 315℃~345℃ for hydrogenation reaction, and the effluent from the first reactor is heated to 427℃ in a heating furnace and enters the second reactor for deep hydrogenation refining.

[0006] However, due to factors such as the large amount of unstable substances, impurities, high sulfur and nitrogen content, and substances that are prone to coking in tire oil, there are still many problems in producing high-quality fuel oil. Summary of the Invention

[0007] The purpose of this application is to provide a method for preparing clean fuel oil by hydrogenating tire distillation oil to solve the above problems.

[0008] To achieve the above objectives, this application adopts the following technical solutions:

[0009] A method for preparing clean fuel oil by hydrogenating tire retort oil, comprising:

[0010] The tire distillation oil is filtered and mixed with hydrogen, and after the first heat exchange, enters the pre-hydrogenation reactor for pre-hydrogenation reaction;

[0011] The product of the pre-hydrogenation reaction is heated and then enters the main hydrogenation reactor for the main hydrogenation reaction. The product of the main hydrogenation reaction undergoes a second heat exchange and cooling, and then passes through a high-pressure separator and a low-pressure separator to separate and obtain fuel oil.

[0012] The pre-hydrogenation reactor is filled with a pre-hydrogenation catalyst, wherein the pre-hydrogenation catalyst uses macroporous alumina as a carrier, one or more of Group IA metals as a first modified metal, and one or more of W, Mo, Ni, and Co as a first active metal;

[0013] The upper part of the main hydrogenation reactor is loaded with a first main hydrogenation catalyst, which is obtained by using alumina and modified molecular sieve as carriers, and then loading a second active metal and an auxiliary metal after steam aging treatment; the second active metal includes one or more of W, Mo, Ni, and Co, and the auxiliary metal includes one or more of vanadium, zirconium, and lanthanide metals;

[0014] The lower part of the main hydrogenation reactor is filled with a second main hydrogenation catalyst, wherein the second main hydrogenation catalyst uses alumina and the modified molecular sieve as carriers, TiO2 and / or NiO as a second modified metal, and one or more of W, Mo, and Co as a third active metal;

[0015] The preparation method of the modified molecular sieve comprises: adding 1wt%-5wt% of a template agent, dodecyl primary amine, and 5wt%-15wt% of silica sol to the molecular sieve, mixing, and drying at room temperature for at least 24 hours to obtain the modified molecular sieve.

[0016] Preferably, the first modified metal accounts for 0.1%-3% of the total mass of the pre-hydrogenation catalyst in an oxidized state, and the first active metal accounts for 3%-15% of the total mass of the pre-hydrogenation catalyst in an oxidized state.

[0017] Preferably, the pre-hydrogenation catalyst is in the shape of a hollow gear ball, and the particle size of the pre-hydrogenation catalyst loaded from bottom to top increases and the loading amount decreases.

[0018] Preferably, the second active metal accounts for 3%-50% of the total mass of the first main hydrogenation catalyst in an oxidized state, and the promoter metal accounts for 0.3%-0.5% of the total mass of the first main hydrogenation catalyst in an oxidized state.

[0019] Preferably, the second modifying metal accounts for 0.5%-10% of the total mass of the second main hydrogenation catalyst, and the third active metal accounts for 11%-19% of the total mass of the second main hydrogenation catalyst in an oxidized state.

[0020] Preferably, the first main hydrogenation catalyst is in a three-leaf clover shape or a four-leaf clover shape, and the second main hydrogenation catalyst is in a cylindrical bar shape.

[0021] Preferably, a first cold hydrogen pipeline is provided at the material inlet of the pre-hydrogenation reactor, and a second cold hydrogen pipeline is provided in the middle of the main hydrogenation reactor.

[0022] Preferably, the tire distillation oil is preheated to 80-100°C before filtering, the end point temperature of the first heat exchange is 180-200°C, and the end point temperature of the heating is 280-360°C.

[0023] Preferably, the gaseous material is obtained at the top of the high-pressure separator and sent to the circulating hydrogen separator, and the circulating hydrogen separator is separated to obtain circulating hydrogen and sulfur-containing wastewater; the separated material at the bottom of the high-pressure separator is input into the low-pressure separator, and the fuel oil and low-pressure gas are obtained after separation by the low-pressure separator; the sulfur-containing wastewater is separated at the bottom of the high-pressure separator.

[0024] Preferably, the temperature of the pre-hydrogenation reaction is 140-230°C, and the volume space velocity is 0.5-1.5h -1 , hydrogen-oil volume ratio is 300-800, reaction pressure is 8.0-16.0MPa; the temperature of the main hydrogenation reaction is 240-360℃, volume space velocity is 0.3-1.0h -1 , the hydrogen-oil volume ratio is 500-800, and the reaction pressure is 8.0-16.0MPa.

[0025] Compared with the prior art, the advantages of this application include:

[0026] The present application provides a method for hydrogenating tire distillate oil to produce clean fuel oil. The method comprises the following steps: in a pre-hydrogenation reactor at a lower temperature, the hydrogenated material after heat exchange is first converted into relatively stable components that release relatively little heat. In the pre-hydrogenation reactor, all diolefins in the tire oil are converted into alkanes or alkenes, and alkenyl aromatics are converted into alkyl aromatics to prevent these highly active components from entering the main hydrogenation reactor and causing the main reactor to overheat. A series of refining reactions, such as hydrodesulfurization, denitrogenation, and deoxygenation, are carried out in the upper portion of the main reactor to convert organic sulfur, nitrogen, and oxygen in the feedstock into inorganic sulfur, nitrogen, and oxygen compounds. The hydrorefined material is then subjected to a reforming catalyst in the lower portion to selectively convert macromolecular substances into gasoline and diesel components primarily containing 6 to 16 carbon atoms.

[0027] This method not only solves the defects of tire oil with high residual carbon powder and many unsaturated components, which are prone to coking during direct hydrorefining and are not conducive to long-term operation of the device, but also solves the problem that the wax oil component in tire oil has a high freezing point and cannot be used, thereby ensuring the long-term safe, stable, smooth, full and excellent operation of the device, and the main indicators of the obtained product meet the requirements of clean fuel oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0029] Figure 1 Schematic diagram of the structure of the hydrogenation device used in the embodiment.

[0030] Reference numerals:

[0031] 1-Filter; 2-Raw oil tank; 3-High-pressure feed pump; 4-New hydrogen compressor; 5-Circulating hydrogen compressor; 6-Heat exchanger; 7-Pre-hydrogenation reactor; 8-Heating furnace; 9-Main hydrogenation reactor; 10-Cooler; 11-High-pressure separator; 12-Low-pressure separator; 13-Desalted water tank; 14-High-pressure water injection pump; 15-Circulating hydrogen separator tank. DETAILED DESCRIPTION

[0032] Now let’s first give an overall statement of this application, which is as follows:

[0033] A method for preparing clean fuel oil by hydrogenating tire retort oil, comprising:

[0034] The tire distillation oil is filtered and mixed with hydrogen, and after the first heat exchange, enters the pre-hydrogenation reactor for pre-hydrogenation reaction;

[0035] Tire retort oil is a liquid product obtained through high-temperature, oxygen-free retort of waste tires. The purpose of filtration is to remove impurities 10 microns or larger, including fine particles like carbon black generated during the tire retort process, to prevent these substances from entering the hydrogenation unit and impacting its operation. The first heat exchange process increases the tire oil's flow rate and, under the protection of hydrogen, prevents the oil from spending too long in the high-temperature zone, which could cause high-temperature rubber buildup.

[0036] The product of the pre-hydrogenation reaction is heated and then enters the main hydrogenation reactor for the main hydrogenation reaction. The product of the main hydrogenation reaction undergoes a second heat exchange and cooling, and then passes through a high-pressure separator and a low-pressure separator to separate and obtain fuel oil.

[0037] The high-pressure separator and the low-pressure separator perform gas-liquid separation.

[0038] In the pre-hydrogenation reactor, all dienes in the tire oil are converted into alkanes or alkenes, and alkenyl aromatics are converted into alkyl aromatics to prevent these very active components from entering the main hydrogenation reactor;

[0039] The pre-hydrogenation reactor is filled with a pre-hydrogenation catalyst, wherein the pre-hydrogenation catalyst uses macroporous alumina as a carrier, one or more of Group IA metals as a first modified metal, and one or more of W, Mo, Ni, and Co as a first active metal;

[0040] The upper part of the main hydrogenation reactor is loaded with a first main hydrogenation catalyst, which is obtained by using alumina and modified molecular sieve as carriers, and then loading a second active metal and an auxiliary metal after steam aging treatment; the second active metal includes one or more of W, Mo, Ni, and Co, and the auxiliary metal includes one or more of vanadium, zirconium, and lanthanide metals;

[0041] Promoter metals can enable the catalyst to maintain its high hydrogenation activity in an environment with high hydrogen sulfide and ammonia.

[0042] The lower part of the main hydrogenation reactor is filled with a second main hydrogenation catalyst, wherein the second main hydrogenation catalyst uses alumina and modified molecular sieve as carriers, TiO2 and / or NiO as a second modified metal, and one or more of W, Mo, and Co as a third active metal;

[0043] The preparation method of the modified molecular sieve comprises: adding 1wt%-5wt% (based on the amount of the molecular sieve) of a template agent, dodecyl primary amine, and 5wt%-15wt% of silica sol to the molecular sieve, mixing, and then drying at room temperature for at least 24 hours to obtain the modified molecular sieve.

[0044] The composition of silica sol is shown in Table 1 below:

[0045] Table 1 Composition of silica sol

[0046] project Product indicators Silicon dioxide content% 30 Average particle size nm 10～20 Chloride ion content% <0.01 Sodium ion content% <0.06 Iron ion content% <0.01 Viscosity CPS <10

[0047] Optionally, the added amount of dodecyl primary amine as a template agent can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt% or any value between 1wt% and 5wt%, and the added amount of silica sol as a silicon source can be 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt% or any value between 5wt% and 15wt%.

[0048] The reforming catalyst (secondary primary hydrogenation catalyst) selectively converts the macromolecular components of the material, which has been freed of sulfur, nitrogen, and other substances, into gasoline components primarily composed of carbons 4 to 12 and diesel components primarily composed of carbons 10 to 22. This increases the cetane number of the diesel component in the tire oil from approximately 35 to between 49 and 51, meeting the requirements for China VI diesel. The catalyst also saturates the unsaturated bonds produced during the long-chain scission process with hydrogen. The remaining small amount of unconverted macromolecular material is recycled back into the feedstock to participate in the reaction.

[0049] The reason for setting up the upper and lower catalyst combinations in the main hydrogenation reactor is that the sulfur content in tire oil is close to 4000ppm, which is higher than the sulfur content of conventional diesel raw materials. In addition, the sulfur in tire oil is artificially added during the later rubber processing process, and part of the sulfur exists in a network structure, which brings great difficulties to hydrodesulfurization.

[0050] In an optional embodiment, the first modified metal accounts for 0.1%-3% of the total mass of the pre-hydrogenation catalyst in an oxidized state, and the first active metal accounts for 3%-15% of the total mass of the pre-hydrogenation catalyst in an oxidized state.

[0051] It can be understood that the proportion of the first modified metal in the total mass of the pre-hydrogenation catalyst calculated in an oxidized state can be 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3% or any value between 0.1% and 3%, and the proportion of the first active metal in the total mass of the pre-hydrogenation catalyst calculated in an oxidized state can be 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or any value between 3% and 15%.

[0052] In an optional embodiment, the pre-hydrogenation catalyst is in the shape of a hollow gear ball, and the particle size of the pre-hydrogenation catalyst loaded from bottom to top increases and the loading amount decreases.

[0053] The reactor is loaded with the smallest particles and the largest loading amount at the bottom, resulting in the highest reaction activity and depth. Moving upward, the catalyst particles gradually increase, the loading amount gradually decreases, and the hydrogenation activity and depth of hydrogenation also decrease. The catalyst at the top reacts with the material first, at which point the catalyst activity and depth of reaction are the weakest, primarily hydrogenating the most easily unsaturated components in the feedstock. Moving downward, as the catalyst particles decrease and the catalyst loading amount increases, the reaction activity also increases, gradually reacting the less reactive materials in the feedstock. As the reaction progresses from top to bottom, the temperature in the reactor gradually increases at the bottom due to the exothermic reaction, and the reaction in the lower part gradually intensifies. In short, this catalyst loading method effectively controls the concentrated reaction and exothermicity of the materials, allowing the entire reaction to proceed smoothly, ensuring a stepped distribution of hydrogenation activity and avoiding the tendency for violent reactions to cause coking. In short, using multiple catalyst sizes and loading them in a sequential order solves the problem of overly violent local reactions, which can lead to high, difficult-to-control temperatures and runaway temperatures or coking.

[0054] In an optional embodiment, the second active metal accounts for 3%-50% of the total mass of the first main hydrogenation catalyst in an oxidized state, and the promoter metal accounts for 3%-5% of the total mass of the first main hydrogenation catalyst in an oxidized state.

[0055] It can be understood that the second active metal, calculated in an oxidized state, accounts for 3%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% or any value between 3% and 50% of the total mass of the first main hydrogenation catalyst, and the promoter metal, calculated in an oxidized state, accounts for 0.3%, 0.4%, 0.5% or any value between 0.3% and 0.5% of the total mass of the first main hydrogenation catalyst.

[0056] In an optional embodiment, the second modified metal accounts for 0.5%-10% of the total mass of the second main hydrogenation catalyst, and the third active metal accounts for 11%-19% of the total mass of the second main hydrogenation catalyst in an oxidized state.

[0057] It will be understood that the second modified metal accounts for 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or any value between 0.5% and 10% of the total mass of the second main hydrogenation catalyst, and the third active metal, calculated in an oxidized state, accounts for 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or any value between 11% and 19% of the total mass of the second main hydrogenation catalyst.

[0058] In an optional embodiment, the first main hydrogenation catalyst is in a three-leaf clover shape or a four-leaf clover shape, and the second main hydrogenation catalyst is in a cylindrical bar shape.

[0059] In an optional embodiment, a first cold hydrogen pipeline is provided at the material inlet of the pre-hydrogenation reactor, and a second cold hydrogen pipeline is provided in the middle of the main hydrogenation reactor.

[0060] The purpose of setting a cold hydrogen pipeline at the inlet of the pre-hydrogenation reactor is: once the temperature of the main hydrogenation reactor is too high, the temperature of the material flowing out of the main hydrogenation reactor will also rise, which will cause the temperature of the raw material entering the pre-reactor to overheat after heat exchange. Once this happens, the inlet temperature of the pre-hydrogenation reactor can be controlled by the cold hydrogen pipeline. A cold hydrogen pipeline is set in the middle of the main hydrogenation reactor to control the high reaction temperature of the lower catalyst bed caused by the excessive temperature rise of the upper catalyst bed. The cold hydrogen pipeline is set in the middle of the main hydrogenation reactor. The principle is that the heat released by the hydrogenated material during the reaction of the upper reaction bed (the upper part of the main hydrogenation reactor) is too large, which will cause the temperature of the lower catalyst bed (the lower part of the main hydrogenation reactor) to be higher, and the reaction temperature of the lower part of the reactor to be too high. The fresh modified catalyst (main hydrogenation catalyst) is more active. If the temperature is too high, it will accelerate the irregular cracking of oil products, causing the gas content to increase, affecting the yield of the device.

[0061] In an optional embodiment, the tire distillation oil is preheated to 80-100°C before filtering, the end temperature of the first heat exchange is 180-200°C, and the end temperature of the heating is 280-360°C.

[0062] The endpoint temperature of the first heat exchange is preferably 180°C. As the catalyst activity gradually decreases, the reaction temperature is slowly increased to 200°C according to product quality. At this temperature, contact with the catalyst removes highly active, easily polymerized rubber in the tire oil, and releases a large amount of heat during hydrogenation.

[0063] It is understood that, before the filtration, the tire distillation oil is preheated to 80°C, 90°C, 100°C, or any value between 80-100°C; the endpoint temperature of the first heat exchange is 180°C, 190°C, 200°C, or any value between 180-200°C; and the endpoint temperature of the heating is 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, or any value between 280-360°C.

[0064] In an optional embodiment, the gaseous material is obtained at the top of the high-pressure separator and sent to a circulating hydrogen separator, and the circulating hydrogen separator separates and obtains circulating hydrogen and sulfur-containing wastewater; the lower separation material of the high-pressure separator is input into the low-pressure separator, and the fuel oil and low-pressure gas are obtained after separation by the low-pressure separator; the bottom separation of the high-pressure separator obtains sulfur-containing wastewater.

[0065] In an optional embodiment, the temperature of the pre-hydrogenation reaction is 140-230°C, and the volume space velocity is 0.5-1.5h -1 , hydrogen-oil volume ratio is 300-800, reaction pressure is 8.0-16.0MPa; the temperature of the main hydrogenation reaction is 240-360℃, volume space velocity is 0.3-1.0h -1 , the hydrogen-oil volume ratio is 500-800, and the reaction pressure is 8.0-16.0MPa.

[0066] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, the conditions are carried out according to conventional conditions or manufacturer recommendations. The reagents or instruments used are not specified by the manufacturer and are conventional products that can be purchased commercially.

[0067] Example

[0068] like Figure 1 As shown, this embodiment provides a method for preparing clean fuel oil by hydrogenating tire distillation oil, which specifically includes the following steps:

[0069] Tire distillation oil is preheated to 95°C, filtered through a filter 1, and then enters a raw oil tank 2. It is then mixed with hydrogen from a new hydrogen compressor 4 and a circulating hydrogen compressor 5 under the action of a high-pressure feed pump 3. After being heat exchanged to 200°C in a first heat exchanger 6, it enters the interior of a pre-hydrogenation reactor 7 from the top for a pre-hydrogenation reaction. The pre-hydrogenation reactor 7 is filled with a pre-hydrogenation catalyst, which uses macroporous alumina as a carrier, "potassium and cesium" from the IA group metals as the first modifying metal, and W, Mo, and Co as the first active metals. The first modifying metal, calculated in its oxidized state, accounts for 0.2% of the total mass of the pre-hydrogenation catalyst (the average amount of each element), and the first active metal, calculated in its oxidized state, accounts for 15% of the total mass of the pre-hydrogenation catalyst (the amounts of W, Mo, and Co are 7%, 5%, and 3%, respectively). The pre-hydrogenation catalyst is in the shape of a hollow gear ball. The particle size of the pre-hydrogenation catalyst loaded from top to bottom decreases and the loading amount increases (the diameters are 6 mm, 4 mm, and 2 mm, respectively, and the loading volume ratio is 2:3:5).

[0070] The product of the pre-hydrogenation reaction is heated to 280°C in a heating furnace 8 before entering a main hydrogenation reactor 9 for the main hydrogenation reaction. The upper portion of the main hydrogenation reactor 9 is loaded with a first main hydrogenation catalyst. This first main hydrogenation catalyst is supported by alumina and a modified molecular sieve, and is steam-aged and then loaded with a second active metal and a promoter metal. The second active metal is W, Mo, or Ni, and the promoter is phosphorus. The second active metal, calculated in its oxidized form, accounts for 23% of the total mass of the first main hydrogenation catalyst (W, Mo, and Ni are used in amounts of 12%, 9%, and 2%, respectively). The promoter metal, calculated in its oxidized form, accounts for 3% of the total mass of the first main hydrogenation catalyst. The lower portion of the main hydrogenation reactor 9 is loaded with a second main hydrogenation catalyst. This second main hydrogenation catalyst is supported by alumina and a modified molecular sieve, with TiO2 as the second modifying metal and a third active metal selected from W, Mo, and Co. The second modifying metal accounts for 5% of the total mass of the second main hydrogenation catalyst, and the third active metal, calculated in its oxidized state, accounts for 17% of the total mass of the second main hydrogenation catalyst (the amounts of W, Mo, and Co are 10%, 5%, and 2%, respectively). The first main hydrogenation catalyst is clover-shaped, and the second main hydrogenation catalyst is cylindrical.

[0071] The material inlet of the pre-hydrogenation reactor 7 is provided with a first cold hydrogen pipeline, and the middle part of the main hydrogenation reactor 9 is provided with a second cold hydrogen pipeline.

[0072] The product of the main hydrogenation reaction is heat exchanged in the first heat exchanger 6, cooled in the cooler 10, and separated into fuel oil using the high-pressure separator 11 and the low-pressure separator 12.

[0073] Tire oil contains high levels of organic sulfides, nitrides, and small amounts of chlorides. These substances are converted into organic substances such as H₂S, NH₃, and HCl during the reaction in pre-hydrogenation reactor 7. These three substances, when present together, generate ammonium sulfide and ammonium chloride salts, which are not only corrosive to equipment but also can crystallize and clog pipelines, potentially causing safety hazards. Therefore, in this application, water injection points are provided before and after heat exchanger 6 in the reaction product outflow line (desalted water tank 13 delivers water to these points via high-pressure water injection pump 14) to dissolve the various ammonium salts produced during tire oil hydrogenation. During normal production, desalted water is injected into the rear portion of heat exchanger 6. If a pressure differential is detected before and after heat exchanger 6, indicating ammonium salt crystallization within heat exchanger 6, the water injection point is switched to the front portion of heat exchanger 6. Once the pressure differential disappears, the water injection point is switched back to the rear portion of heat exchanger 6.

[0074] The gaseous material is obtained at the top of the high-pressure separator 11 and sent to the circulating hydrogen separator 15, where it is separated to obtain circulating hydrogen and sulfur-containing wastewater; the lower separated material of the high-pressure separator 11 is input to the low-pressure separator 12, where fuel oil and low-pressure gas are obtained after separation; the bottom of the high-pressure separator 11 is separated to obtain sulfur-containing wastewater.

[0075] The pre-hydrogenation reaction temperature is 160 ° C and the volume space velocity is 0.5h -1 , hydrogen-oil volume ratio is 500, reaction pressure is 12.0MPa; main hydrogenation reaction temperature is 280℃, volume space velocity is 0.4h -1 , the hydrogen-oil volume ratio is 600, and the reaction pressure is 12.0MPa.

[0076] Comparative Example 1

[0077] Different from the embodiment, the mixed hydrogen raw material is directly heated to the temperature required for hydrogenation refining after heat exchange according to the traditional process.

[0078] The reaction results of Example 1 and Comparative Example 1 are shown in Table 2 below:

[0079] Table 2 Reaction results of Example 2 and Comparative Example 1

[0080] Operating time Comparative Example 1 Example Product quality qualified qualified Target product yield 80％ 98％ Operating time Coking occurs after 460 hours >2000 hours

[0081] Comparative Example 2

[0082] The pre-hydrogenation reactor 7 is loaded with the same catalyst A. Its properties are shown in Table 3 below:

[0083] Table 3 Properties of Catalyst A

[0084] Brand Catalyst A shape gear ball Diameter, mm 5.0-6.5 Compressive strength, N / mm ≮4 Active metal components Mo-Ni Metal content, % 3.5-4.5 Pore volume, ml / g ≮0.5 Specific surface area, m2 / g ≮100 Bulk density, g / ml 0.50～0.60

[0085] Comparative Example 3

[0086] The pre-hydrogenation reactor 7 is loaded with the same catalyst B. Its properties are shown in Table 4 below:

[0087] Table 4 Properties of Catalyst B

[0088] Brand Catalyst B shape sphere Diameter, mm 3.0-4.0 Compressive strength, N / mm ≮4 Active metal components Mo-Ni Metal content, % 5.5-6.5 Pore volume, ml / g ≮0.5 <![CDATA[Specific surface area, m 2 / g]]> ≮80 Bulk density, g / ml 0.50～0.60

[0089] When implementing the solution of the present application, the reactor inlet temperature is controlled at 160°C, and the reactor temperature rise distribution, product quality and device coking conditions are monitored at any time.

[0090] The reaction results of Example 2 and Comparative Example 3 are shown in Table 5 below:

[0091] Table 5 Reaction results of Example 2 and Comparative Example 3

[0092]

[0093] Comparative Example 4

[0094] Different from the embodiment, the catalyst loaded in the pre-hydrogenation reactor has the same particle size from top to bottom.

[0095] The reaction test results are shown in Table 6 below:

[0096] Table 6 Test results

[0097]

[0098] Comparative Example 5

[0099] A conventional diesel hydro-reforming catalyst was selected as the catalyst for the main hydrogenation reactor. Its properties are shown in Table 7 below:

[0100] Table 7 Properties of traditional diesel hydroreforming catalysts

[0101] Brand catalyst shape Shamrock Diameter, mm 2.5-3.0 Length, mm 2～10 Compressive strength, N / mm ≮12 Active metal components Mo-Ni Metal content, % 15-20 Additives,% 1-2 Pore volume, ml / g ≮0.35 <![CDATA[Specific surface area, m 2 / g]]> ≮160 Bulk density, g / ml 0.60～0.70

[0102] Comparative Example 6

[0103] A conventional diesel hydrocracking catalyst was selected as the catalyst for the main hydrogenation reactor. Its properties are shown in Table 8 below:

[0104] Table 8 Properties of traditional diesel hydro-reforming catalysts

[0105] Brand catalyst shape Shamrock Diameter, mm 1.8-2.0 Length, mm 2～10 Compressive strength, N / mm ≮8 Active metal components Mo-Ni Metal content, % 15-25 Additives,% 2-3 Pore volume, ml / g ≮0.35 <![CDATA[Specific surface area, m 2 / g]]> ≮130 Bulk density, g / ml 0.60～0.70

[0106] The reaction results of Example 5 and Comparative Example 6 are shown in Table 9 below

[0107] Table 9 Reaction results of Example 5 and Comparative Example 6

[0108]

[0109] In order to further illustrate the importance of the catalyst loading scheme, a loading scheme comparison is conducted, as shown in Table 10 below:

[0110] Table 10 Comparison of filling schemes

[0111]

[0112] Comparative Example 7 and Comparative Example 8

[0113] To verify the effectiveness of the catalyst at the top of the main hydrogenation reactor of the present invention in removing sulfur from tire oil, a conventional domestic diesel hydrorefining catalyst (Comparative Example 7) and an industrial diesel hydrorefining catalyst produced by our company (Comparative Example 8) were used as reference agents. Comparative tests were conducted with the catalyst produced in the present invention using tire oil under the same conditions. The sulfur content of the feedstock used was 3650 ppm, and the comparison results were based on the sulfur content of the product. The catalyst compositions are shown in Table 11 below:

[0114] Table 11 Catalyst components used in Comparative Examples 7 and 8

[0115] Chemical composition Comparative Example 7 Catalyst Comparative Example 8 Catalyst Metal content (m%) 17.0～21.0 20.0～23.0 additives 0.5～1.5 3.5～4.5 <![CDATA[Specific surface area (m 2 / g)]]> ≥130 ≥150 Pore volume (ml / g) ≥0.35 ≥0.35 Crushing strength (N / cm) ≥150 ≥120 Appearance and shape Four-leaf clover clover-shaped Bulk density (g / ml) 0.58～0.68 0.60～0.70 Particle size (mm) Φ1.4X(3~7) Φ1.6X(3~8)

[0116] The reaction results of Example 7 and Comparative Example 8 are shown in Table 12 below:

[0117] Table 12 Reaction results of Example 7 and Comparative Example 8

[0118] Comparative Example 7 Comparative Example 8 Example Product sulfur content 149ppm 147ppm 6.7ppm

[0119] The results in Table 12 show that the product obtained by the catalyst provided in this application has an extremely low sulfur content, and the effect is far better than that of Comparative Examples 7 and 8.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

[0121] Furthermore, those skilled in the art will appreciate that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and to form distinct embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is intended solely to enhance understanding of the overall background of this application and should not be construed as an admission or any implication that such information constitutes prior art known to those skilled in the art.

Claims

1. A method for preparing clean fuel oil by hydrogenating tire distillation oil, characterized in that: include: The tire distillation oil is filtered and mixed with hydrogen, and after the first heat exchange, enters the pre-hydrogenation reactor for pre-hydrogenation reaction; The product of the pre-hydrogenation reaction is heated and then enters the main hydrogenation reactor for the main hydrogenation reaction. The product of the main hydrogenation reaction undergoes a second heat exchange and cooling, and then passes through a high-pressure separator and a low-pressure separator to separate and obtain fuel oil. The pre-hydrogenation reactor is filled with a pre-hydrogenation catalyst, wherein the pre-hydrogenation catalyst uses macroporous alumina as a carrier, one or more Group IA metals as a first modified metal, and W, Mo and Co as a first active metal; The upper part of the main hydrogenation reactor is loaded with a first main hydrogenation catalyst, which is obtained by using alumina and modified molecular sieve as carriers, and then loading a second active metal and phosphorus after steam aging treatment; the second active metal is W, Mo and Ni; The lower part of the main hydrogenation reactor is filled with a second main hydrogenation catalyst, wherein the second main hydrogenation catalyst uses alumina and the modified molecular sieve as carriers, TiO2 and / or NiO as a second modified metal, and W, Mo and Co as a third active metal; The preparation method of the modified molecular sieve comprises: adding 1 wt% to 5 wt% of a template agent, dodecyl primary amine, and 5 wt% to 15 wt% of silica sol to the molecular sieve, mixing, and then drying at room temperature for at least 24 hours to obtain the modified molecular sieve; The first modified metal accounts for 0.1%-3% of the total mass of the pre-hydrogenation catalyst in an oxidized state, and the first active metal accounts for 3%-15% of the total mass of the pre-hydrogenation catalyst in an oxidized state; The pre-hydrogenation catalyst is in the shape of a hollow gear ball, and the particle size of the pre-hydrogenation catalyst loaded from bottom to top increases and the loading amount decreases; The second active metal accounts for 3% to 50% of the total mass of the first main hydrogenation catalyst in an oxidized state, and the phosphorus accounts for 3% of the total mass of the first main hydrogenation catalyst in an oxidized state; The second modified metal accounts for 0.5%-10% of the total mass of the second main hydrogenation catalyst, and the third active metal accounts for 11%-19% of the total mass of the second main hydrogenation catalyst calculated in an oxidized state.

2. The method according to claim 1, characterized in that The first main hydrogenation catalyst is in a three-leaf clover shape or a four-leaf clover shape, and the second main hydrogenation catalyst is in a cylindrical bar shape.

3. The method according to claim 1, characterized in that The material inlet of the pre-hydrogenation reactor is provided with a first cold hydrogen pipeline, and the middle part of the main hydrogenation reactor is provided with a second cold hydrogen pipeline.

4. The method according to claim 1, wherein The tire distillation oil is preheated to 80-100° C. before filtering, the end point temperature of the first heat exchange is 180-200° C., and the end point temperature of the heating is 280-360° C.

5. The method according to claim 1, wherein The gaseous material is obtained at the top of the high-pressure separator and sent to the circulating hydrogen separator, and the circulating hydrogen separator separates and obtains circulating hydrogen and sulfur-containing wastewater; the separated material at the bottom of the high-pressure separator is input into the low-pressure separator, and the fuel oil and low-pressure gas are obtained after separation by the low-pressure separator; the sulfur-containing wastewater is separated at the bottom of the high-pressure separator.

6. The method according to any one of claims 1 to 5, characterized in that The temperature of the pre-hydrogenation reaction is 140-230°C, and the volume space velocity is 0.5-1.5h -1 , hydrogen-oil volume ratio is 300-800, reaction pressure is 8.0-16.0MPa; the temperature of the main hydrogenation reaction is 240-360℃, volume space velocity is 0.3-1.0h -1 , the hydrogen-oil volume ratio is 500-800, and the reaction pressure is 8.0-16.0MPa.

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