Method and system for series hydrotreatment of waste tire pyrolysis oil

Abstract

The invention relates to the technical field of waste tire pyrolysis oil treatment, in particular to a method and system for series hydrotreatment of waste tire pyrolysis oil, and the method comprises the following steps: S1, mixing pretreated waste tire pyrolysis oil with mixed hydrogen, and then carrying out primary preheating and low-temperature hydrotreatment; s2, performing hydrofining reaction and shallow cracking reaction on the low-temperature hydrogenation effluent; s3, performing thermal high-pressure separation treatment on the cracking reaction product to obtain a first gas phase and a first liquid phase; s4, condensing the first gas phase, performing cold high-pressure separation treatment to obtain a second gas phase and a second liquid phase, and performing cold low-pressure separation treatment on the second liquid phase to collect an oil phase; the first liquid phase is subjected to thermal low-pressure separation treatment to obtain a third gas phase and a third liquid phase, and the third gas phase is condensed and then subjected to cold low-pressure separation treatment to collect an oil phase; and S5, mixing the third liquid phase and the oil phase, and carrying out reaction product fractionation treatment. According to the technical scheme, deep processing of the waste tire pyrolysis oil is achieved, energy consumption of the device is reduced, and the continuous operation period of the device is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of waste tire pyrolysis oil treatment, and particularly relates to a method and system for tandem hydrogenation treatment of waste tire pyrolysis oil. Background Art

[0002] With the continuous development of the automobile transportation industry, the generation amount of waste tires has also increased sharply. Due to the characteristics of waste tires such as corrosion resistance and difficulty in decomposition under natural conditions, it has become a "black pollution" problem that attracts attention in China and the world. How to achieve "reduction, harmlessness, greenness, resource utilization, reuse, and recycling" of waste tires is a major issue that urgently needs to be solved in the rubber field. Thermal cracking of waste tires is one of the main ways for recycling waste tires. Waste tire pyrolysis oil is one of the main products generated by the pyrolysis of waste tires. Its density is generally greater than 915 kg / m 3 , and it mainly contains aliphatic hydrocarbons, aromatic hydrocarbons, olefins and resins, as well as non-hydrocarbon compounds such as sulfur, nitrogen, oxygen, and chlorine. Pyrolysis oil has the advantages of high calorific value, low ash content, low viscosity and low residue carbon value, but it also has defects such as relatively poor overall performance compared with diesel and high contents of impurities such as sulfur, nitrogen, and chlorine. Therefore, refining waste tire pyrolysis oil to remove non-hydrocarbon compounds such as sulfur, nitrogen, oxygen, and chlorine contained therein and improving the quality of waste tire pyrolysis oil is an environmentally friendly technology for improving the utilization value of pyrolysis oil, and can also alleviate the current situation of tight oil products in China to a certain extent.

[0003] Due to the addition of various additives during the tire manufacturing process, the content of miscellaneous elements in tire pyrolysis oil is relatively high, especially chlorine and silicon. During the hydrogenation process, they are converted into hydrogen chloride, which has a strong corrosive effect on equipment pipelines. Silicon is extremely likely to block the catalyst pores, resulting in catalyst failure. The existing patent CN105001910A discloses a method for combined hydrotreating of tire pyrolysis oil, a combined process of hydrodechlorination and hydrorefining. Aiming at the high content of impurity elements in waste tire pyrolysis oil, especially the influence of the presence of chlorine element on stainless steel equipment, it is applied to the process of waste tire oil upgrading, so as to achieve the purposes of improving product quality, reducing equipment material, extending the operation cycle of the device, and reducing investment. This invention adopts a two-stage separate hydrogenation process, with a complex process flow, high operation difficulty, and high energy consumption. Patent CN220520438U discloses a deep processing system for tire oil. This utility model consists of a tire oil fractionation part, a diesel fraction hydrorefining part, a gasoline fraction hydrorefining part, etc., and is used for producing diesel and gasoline. This utility model needs to first separate the tire oil into two parts, namely diesel fraction and gasoline fraction, and then process them separately, making the process flow complex, the operation difficulty high, and the product distribution not easy to adjust. Patent CN118006362A discloses a deep processing system for hydrogenating tire pyrolysis oil. This invention is equipped with a pre-furnace hydrogenation reactor and a post-furnace hydrogenation reactor. Through the improvement of the hydrogenation deep processing process of tire pyrolysis oil, a feed three-way valve is provided, which can switch the oil flow direction - select to input the first pre-furnace hydrogenation reactor or the feed heating furnace to extend the operation time of the device. In this way, when the first reactor is blocked, the first reactor will lose its function, and impurities such as dienes, gums, and silicon in the raw materials will quickly cause the post-furnace hydrogenation reactor to be blocked, and the continuous operation time of the device cannot be extended. At the same time, it accelerates the coking and blocking of the catalyst in the post-furnace hydrogenation reactor.

[0004] However, the above technical solutions all have deficiencies. Among them, patent CN105001910A adopts a two-stage separate hydrogenation process, with a complex process flow, high operation difficulty, and high energy consumption; patent CN220520438U needs to first separate the tire oil into two parts, namely diesel fraction and gasoline fraction, and then process them separately, making the process flow complex, the operation difficulty high, and the product distribution not easy to adjust; in patent CN118006362A, when the first reactor is blocked, the first reactor will lose its function, and impurities such as dienes, gums, and silicon in the raw materials will quickly cause the post-furnace hydrogenation reactor to be blocked, and the continuous operation time of the device cannot be extended. At the same time, it accelerates the coking and blocking of the catalyst in the post-furnace hydrogenation reactor. Summary of the Invention

[0005] In view of this, the present invention proposes a method and system for tandem hydrotreating of waste tire pyrolysis oil to solve the technical problems of complex hydrotreating process flow, easy blockage of hydrogenation reactors, and high energy consumption of existing waste tire pyrolysis oil.

[0006] The technical solution of the present invention is realized as follows: The present invention provides a method for tandem hydrotreating waste tire pyrolysis oil, comprising:

[0007] S1. Mix the pretreated waste tire pyrolysis oil and mixed hydrogen, conduct primary preheating, and perform low-temperature hydrotreating;

[0008] S2. After the low-temperature hydrotreating effluent undergoes secondary preheating, a hydrofining reaction is carried out, and the obtained hydrofining effluent undergoes a mild cracking reaction;

[0009] S3. Subject the cracking reaction product to thermal high-pressure separation treatment to obtain a first gas phase and a first liquid phase;

[0010] S4. After the first gas phase is condensed, it undergoes cold high-pressure separation treatment to obtain a second gas phase and a second liquid phase. The second gas phase is subjected to desulfurization treatment to obtain recycled hydrogen, and the second liquid phase undergoes cold low-pressure separation treatment to collect the oil phase; The first liquid phase undergoes thermal low-pressure separation treatment to obtain a third gas phase and a third liquid phase. After the third gas phase is condensed, it undergoes cold low-pressure separation treatment to collect the oil phase;

[0011] S5. The third liquid phase and the oil phase are mixed for reaction product fractionation treatment to obtain naphtha, low-freezing-point diesel components, and tail oil.

[0012] Based on the above technical solution, preferably, in step S1, the pretreatment includes successively performing primary filtration, initial heating, and secondary filtration on the waste tire pyrolysis oil. The filtration accuracy of the primary filtration is 50 - 100 μm, the filtration accuracy of the secondary filtration is 20 - 30 μm, and the temperature of the waste tire pyrolysis oil after initial heating is 110 - 120 °C.

[0013] Based on the above technical solution, preferably, in step S1, the low-temperature hydrotreating is carried out using a low-temperature section reactor. The operating temperature at the reactor inlet is 150 - 180 °C, the operating pressure is 10.0 - 18.0 MPa(G), the volume hourly space velocity of the desilication agent is 4.0 - 6.0 h -1 , the volume hourly space velocity of the protective agent is 1.0 - 3.0 h -1 , the volume hourly space velocity of the main catalyst is 2.0 - 4.0 h -1 , and the hydrogen-oil volume ratio is 500:1 - 1000:1 Nm 3 / m 3 .

[0014] Based on the above technical solution, preferably, the desilication agent is modified activated carbon, the protective agent is silica and / or alumina, and the main catalyst is an alumina catalyst loaded with Ni / Mo.

[0015] Based on the above technical solution, preferably, the preparation method of the modified activated carbon includes:

[0016] A1. Pretreat activated carbon in an acidic solution, mix the pretreated activated carbon with 3-aminopropyltriethoxysilane in anhydrous toluene, and reflux at 100 - 120 °C for 6 - 8 h to obtain silane-modified activated carbon;

[0017] A2. Mix the silane-modified activated carbon with melamine, and heat-treat at 300 - 350 °C for 1 - 2 h under nitrogen protection to obtain modified activated carbon.

[0018] Based on the above technical solutions, preferably, in step S2, the temperature of the low-temperature hydrogenation effluent is raised to 340 - 360 °C after secondary preheating; the hydrofining reaction uses a hydrofining reactor, the inlet operating temperature of the hydrofining reactor is 320 - 360 °C, the operating pressure is 10.0 - 18.0 MPa(G), and the volumetric space velocity of the hydrofining catalyst is 0.5 - 2.0 h -1 。

[0019] Based on the above technical solutions, preferably, mild cracking uses a reforming reactor, the inlet operating temperature of the reforming reactor is 330 - 350 °C, the volumetric space velocity of the hydrocracking catalyst is 3.0 - 6.0 h -1 , and the hydrogen-oil volume ratio is 500:1 - 1000:1 Nm 3 / m 3 。

[0020] Based on the above technical solutions, preferably, before the thermal high-pressure separation treatment of the cracking reaction product, it further includes: cooling the cracking reaction product to 250 - 270 °C; the thermal high-pressure separation treatment is carried out using a thermal high-pressure separator, and the process parameters of the thermal high-pressure separator include: the stripping internals use sieve trays or valve trays, and the flow rate of the hot hydrogen is 10 - 25% of the recycle hydrogen flow rate; the temperature of the hot hydrogen is 20 - 30 °C higher than the temperature of the reaction product.

[0021] Based on the above technical solutions, preferably, before the first gas-phase condensation treatment and before the third gas-phase condensation treatment, both include stepwise continuous injection of an alkaline solution for treatment, and the alkaline solution is one or more of Na 2 CO 3 solution, NaOH solution, KOH solution, ammonia water.

[0022] The present invention also proposes a system for tandem hydrotreating waste tire pyrolysis oil, and the system is used to implement a method for tandem hydrotreating waste tire pyrolysis oil as described above. The system includes:

[0023] A pretreatment module for pretreating waste tire pyrolysis oil, at least including a primary filter and a group of heat exchangers;

[0024] The low-temperature hydrogenation module is used for low-temperature hydrogenation treatment of preheated waste tire pyrolysis oil, and includes at least two groups of parallel low-temperature hydrogenation reactors;

[0025] The hydrofining and upgrading module is used for hydrofining and cracking treatment of the low-temperature hydrogenation effluent, and includes a series-connected hydrofining reactor and an upgrading reactor;

[0026] The separation and purification module is used for separating the cracking reaction products, and includes a hot high-pressure separator, a cold high-pressure separator, a hot low-pressure separator and a cold low-pressure separator. The feed inlet of the hot high-pressure separator is connected to the upgrading reactor, the liquid phase outlet is connected to the hot low-pressure separator, and the gas phase outlet is connected to the cold high-pressure separator; the gas phase outlet of the hot low-pressure separator and the oil phase outlet of the cold high-pressure separator are respectively connected to the cold low-pressure separator;

[0027] The reaction product fractionation module is used for fractionating the liquid phase product of the hot low-pressure separator and the oil phase product of the cold low-pressure separator;

[0028] The circulating hydrogen mixing module is used for recovering and treating the hydrogen in the separated gas phase and supplying it to the low-temperature hydrogenation module and the hydrofining and upgrading module.

[0029] The method and system for tandem hydrogenation treatment of waste tire pyrolysis oil of the present invention have the following beneficial effects compared with the prior art:

[0030] (1) Through source control and process collaborative optimization, the present invention realizes the efficient and clean conversion of waste tire pyrolysis oil. By classifying and recycling waste tires, the introduction of chlorinated rubber raw materials is reduced, and the risk of chlorine corrosion in the subsequent hydrogenation system is significantly reduced, giving full play to the advantages of the tandem hydrogenation process in terms of investment cost, energy consumption and operation stability; at the same time, based on the characteristics of high silicon and high metal impurities in pyrolysis oil, a low-temperature reactor and a staged loading system are designed to efficiently remove silicon, alkali metals (Ca, Na), Fe and dienes under mild conditions, avoiding poisoning of the main catalyst and coking of the reactor, and extending the continuous operation cycle of the system;

[0031] (2) Through the staged matching loading of the desiliconizing agent (modified activated carbon), protective agent and main catalyst in the low-temperature reactor, a gradient adsorption-catalysis synergistic system is formed. The desiliconizing agent selectively adsorbs silicon compounds through amino coordination and π-π interaction of the triazine ring, the protective agent intercepts alkali metals through ion exchange, and the main catalyst saturates dienes at low temperature. The synergistic effect of the three extends the service life of the catalyst and greatly reduces the risk of reactor coking and blockage;

[0032] (3) Inject alkaline solution at key nodes such as the hot high-pressure gas air cooler and the hot low-pressure gas air cooler to accurately control the pH of the aqueous phase to 7.5-9.0. This design neutralizes acidic substances such as H 2 S, HCl, etc., and effectively inhibits NH4 Cl and NH 4 HS crystallization eliminates the risk of sub - crystal corrosion. Meanwhile, the weakly alkaline environment reduces the uniform corrosion rate of equipment pipelines, significantly extending the service life of the equipment.

[0033] (4) According to the characteristics of high aromatic hydrocarbons and low freezing point of the raw materials, the present invention increases the production of light oil to a limited extent and reduces the coking probability. It adopts the heat exchange between the refined reaction product and the gas - mixed hydrogen to control the inlet temperature of the reforming reactor, providing the required energy for the gas - mixed hydrogen and effectively controlling the inlet temperature of the reforming reactor. The waste tire pyrolysis oil is processed by series - connected hydrotreating. Through the hydrogenation saturation of diolefins in the low - temperature section before the furnace, the hydrorefining and hydro - reforming after the furnace, the deep processing of the waste tire pyrolysis oil is realized, and refined naphtha, refined diesel and tail oil can be produced, which has the effects of reducing the energy consumption of the device, extending the continuous operation period of the device, and eliminating the corrosion hidden danger of equipment pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0035] Figure 1 It is a schematic structural diagram of the system for the series - connected hydrotreating of waste tire pyrolysis oil of the present invention.

[0036] The reference numerals are as follows:

[0037] 1. Primary filter; 2. First heat exchanger; 3. Secondary filter; 4. Filtered raw material buffer tank; 5. Reaction feed pump; 6. Second heat exchanger; 7. Low - temperature section reactor; 8. Third heat exchanger; 9. Reaction feed heating furnace; 10. Refining reactor; 11. Fourth heat exchanger; 12. Reforming reactor; 13. Hot high - pressure separator; 14. Hot high - pressure gas air cooler; 15. Cold high - pressure separator; 16. Circulating hydrogen desulfurization tower; 17. Circulating hydrogen compressor; 18. Lean amine liquid pump; 19. Hot low - pressure separator; 20. Fifth heat exchanger; 21. Hot low - pressure gas air cooler; 22. Cold low - pressure separator; 23. Fractionation system; 24. Three - way switching valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in combination with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0039] As shown Figure 1 in the figure, the present invention provides a system for tandem hydrotreating of waste tire pyrolysis oil, and the system includes:

[0040] A pretreatment module for pretreating waste tire pyrolysis oil, including at least a primary filter 1 and a group of heat exchangers;

[0041] A low-temperature hydrogenation module for low-temperature hydrogenation treatment of the preheated waste tire pyrolysis oil, including at least two groups of parallel low-temperature hydrogenation reactors;

[0042] A hydrofining and reforming module for hydrofining and cracking treatment of the low-temperature hydrogenation effluent, including a series-connected hydrofining reactor 10 and a reforming reactor 12;

[0043] A separation and purification module for separating the cracking reaction products, including a hot high-pressure separator 13, a cold high-pressure separator 15, a hot low-pressure separator 19, and a cold low-pressure separator 22. The feed inlet of the hot high-pressure separator 13 is connected to the reforming reactor 12, the liquid phase outlet is connected to the hot low-pressure separator 19, and the gas phase outlet is connected to the cold high-pressure separator 15; the gas phase outlet of the hot low-pressure separator 19 and the oil phase outlet of the cold high-pressure separator 15 are respectively connected to the cold low-pressure separator 22;

[0044] A reaction product fractionation module for fractionating the liquid phase product of the hot low-pressure separator 19 and the oil phase product of the cold low-pressure separator 22;

[0045] A circulating hydrogen mixing module for recovering and treating the hydrogen in the separated gas phase and supplying it to the low-temperature hydrogenation module and the hydrofining and reforming module.

[0046] Further, the pretreatment module includes a primary filter 1, a first heat exchanger 2, a secondary filter 3, and a filtered raw material buffer tank 4 connected in sequence. The filtered raw material buffer tank 4 is connected to the low-temperature hydrogenation module through a reaction feed pump 5 and a second heat exchanger 6.

[0047] The low-temperature hydrogenation module uses at least 2 or more parallel low-temperature hydrogenation reactors, preferably 2 parallel low-temperature hydrogenation reactors, one of which is in operation and one is in hot standby. A three-way valve 24 is provided at the inlet of the low-temperature hydrogenation reactor. The inlet of the three-way valve 24 is connected to the second heat exchanger 6, and the two outlets are respectively connected to the two low-temperature hydrogenation reactors. When the pressure drop of the operating reactor exceeds the allowable value, it is switched to the standby reactor. The standby reactor needs to be in a hot standby state, and a stream of circulating hydrogen is introduced from the shell side outlet of the fifth heat exchanger 20 into the inlet pipeline of the standby reactor to ensure that the temperature difference between the standby reactor system and the operating reactor is less than 80°C.

[0048] The outlet of the low-temperature hydrogenation reactor is connected to the hydrofining and upgrading module through the third heat exchanger 8, the reaction feed heating furnace 9. The hydrofining and upgrading module includes a hydrofining reactor 10 and a reforming reactor 12. The feed inlet of the hydrofining reactor 10 is connected to the reaction feed heating furnace 9, and the outlet is connected to the feed inlet of the reforming reactor 12 through the fourth heat exchanger 11. The outlet of the reforming reactor 12 is connected to the separation and purification module through the third heat exchanger 8.

[0049] The separation and purification module includes a hot high-pressure separator 13, a cold high-pressure separator 15, a hot low-pressure separator 19, and a cold low-pressure separator 22. The feed inlet of the hot high-pressure separator 13 is connected to the outlet of the reforming reactor 12 through the third heat exchanger 8. The gas-phase outlet is connected to the feed inlet of the cold high-pressure separator 15 through the second heat exchanger 6 and the hot high-pressure gas air cooler 14. The liquid-phase outlet is connected to the feed inlet of the hot low-pressure separator 19 through the lean amine liquid pump 18. The oil-phase outlet of the cold high-pressure separator 15 is connected to the cold low-pressure separator 22, the gas-phase outlet is connected to the recycle hydrogen mixing module, and the liquid-phase outlet is connected to the external sewage treatment system. The gas-phase outlet of the hot low-pressure separator 19 is connected to the feed inlet of the cold low-pressure separator 22 through the fifth heat exchanger 20 and the hot low-pressure gas air cooler 21. The liquid-phase outlet is connected to the reaction product fractionation module. The oil-phase outlet of the cold low-pressure separator 22 is connected to the reaction product fractionation module, the gas-phase outlet is connected to the outside, and the liquid-phase outlet is connected to the external sewage treatment system.

[0050] The reaction product fractionation module is a fractionation system 23, which is used to fractionate the liquid-phase product of the hot low-pressure separator 19 and the oil-phase product of the cold low-pressure separator 22 to obtain naphtha, diesel, and tail oil.

[0051] The recycle hydrogen mixing module includes a recycle hydrogen desulfurization tower 16 and a recycle hydrogen compressor 17. The gas-phase feed inlet of the recycle hydrogen desulfurization tower 16 is connected to the gas-phase outlet of the cold high-pressure separator 15, and the liquid-phase feed inlet is connected to the lean amine liquid pump 18. The lean amine liquid is injected into the recycle hydrogen desulfurization tower 16 through the lean amine liquid pump 18. The gas-phase outlet of the recycle hydrogen desulfurization tower 16 is connected to the recycle hydrogen compressor 17. The outlet of the recycle hydrogen compressor 17 is connected to the make-up hydrogen system. The desulfurized recycle hydrogen is mixed with the make-up hydrogen of the make-up hydrogen system after being compressed by the recycle hydrogen compressor 17. The make-up hydrogen system is connected to the second heat exchanger 6 through a pipeline; it is also connected to the low-temperature hydrogenation reactor and the hot high-pressure separator 13 through pipelines, the fifth heat exchanger 20, and the fourth heat exchanger 11 respectively to provide mixed hydrogen for the hydrogenation reaction.

[0052] The present invention also provides a method for serially hydrotreating waste tire pyrolysis oil, including the following steps:

[0053] S1. Mix the pretreated waste tire pyrolysis oil and mixed hydrogen, perform primary preheating, and carry out low-temperature hydrogenation treatment;

[0054] S2. The low-temperature hydrogenation effluent is subjected to a secondary preheating and then a hydrofining reaction, and the obtained hydrofining effluent is subjected to a mild cracking reaction;

[0055] S3. The cracking reaction product is subjected to a thermal high-pressure separation treatment to obtain a first gas phase and a first liquid phase;

[0056] S4. After the first gas phase is condensed, it is subjected to a cold high-pressure separation treatment to obtain a second gas phase and a second liquid phase. The second gas phase is subjected to a desulfurization treatment to obtain recycled hydrogen, and the second liquid phase is subjected to a cold low-pressure separation treatment to collect the oil phase; the first liquid phase is subjected to a thermal low-pressure separation treatment to obtain a third gas phase and a third liquid phase. The third gas phase is condensed and then subjected to a cold low-pressure separation treatment to collect the oil phase;

[0057] S5. The third liquid phase and the oil phase are mixed and subjected to a reaction product fractionation treatment to obtain naphtha, a low-freezing-point diesel component, and tail oil.

[0058] The technical solution for the tandem hydrotreating of waste tire pyrolysis oil provided by the present invention realizes the deep processing of waste tire pyrolysis oil through three-stage reactions of low-temperature hydrogenation pretreatment, hydrofining, and mild cracking, in cooperation with a multi-stage gas-liquid separation and fractionation system 23. This solution not only effectively removes impurities such as sulfur, nitrogen, and oxygen in the raw material, but also optimizes the product distribution through a mild cracking reaction, and finally obtains high-quality products such as naphtha, a low-freezing-point diesel component, and tail oil. The entire process flow, through a reasonable heat utilization and hydrogen recycling system, not only ensures the product quality but also realizes the efficient utilization of energy, demonstrating good industrial application value.

[0059] In step S1, the pretreatment includes successively performing a primary filtration, a primary heating, and a secondary filtration on the waste tire pyrolysis oil. The filtration accuracy of the primary filtration is 50 - 100 μm, the filtration accuracy of the secondary filtration is 20 - 30 μm, and the temperature of the waste tire pyrolysis oil after the primary heating is 110 - 120 °C. Specifically, the primary filter 1 uses a mechanical self-cleaning filter, and the secondary filter 3 uses a Johnson wedge wire filter. This step realizes the step-by-step removal of impurities in the waste tire pyrolysis oil through a two-stage filtration system with progressive accuracy, avoiding the rapid blockage of the fine filter.

[0060] Specifically, the low-temperature hydrogenation treatment is carried out using a low-temperature section reactor 7. The operating temperature at the reactor inlet is 150 - 180 °C, the operating pressure is 10.0 - 18.0 MPa(G), the volume space velocity of the desiliconizing agent is 4.0 - 6.0 h -1 , the volume space velocity of the protective agent is 1.0 - 3.0 h -1 , the volume space velocity of the main catalyst is 2.0 - 4.0 h -1 , and the hydrogen-oil volume ratio is 500:1 - 1000:1 Nm 3 / m 3Among them, the desiliconizing agent is modified activated carbon, the protective agent is silicon dioxide and / or aluminum oxide, which is used to adsorb alkali metals (such as Ca, Na, etc.); the main catalyst is nickel-based alumina catalyst and / or molybdenum-based alumina catalyst.

[0061] In the low-temperature stage reactor 7, the desiliconizing agent, the protective agent and the main catalyst are loaded in a graded matching manner, effectively removing silicon, alkali metals (such as Ca, Na, etc.), Fe, diolefins, etc., prolonging the service life of the catalyst, and greatly reducing the risk of coking and blockage of the reactor.

[0062] The preparation method of the modified activated carbon includes:

[0063] A1. Pretreat the activated carbon in an acidic solution, mix the pretreated activated carbon with aminopropyltriethoxysilane in anhydrous toluene, and reflux at 100-120 °C for 6-8 h to obtain silane-modified activated carbon;

[0064] A2. Mix the silane-modified activated carbon with melamine, and heat-treat at 300-350 °C for 1-2 h under nitrogen protection to obtain modified activated carbon.

[0065] Furthermore, the acidic solution is 3M hydrochloric acid, the pretreatment temperature is 25-30 °C, and the time is 2-3 h; the mass ratio of the pretreated activated carbon to aminopropyltriethoxysilane is 1.5-2:1.

[0066] Furthermore, the mass ratio of the silane-modified activated carbon to melamine is 1:0.2-0.4. First, dissolve melamine in ethanol, add the silane-modified activated carbon, ultrasonically disperse for 30 min, then dry to remove the solvent. Transfer the dried mixture to a quartz boat in a tubular furnace, and under nitrogen protection, heat up to 300-350 °C at a heating rate of 5 °C / min and react for 1-2 h to obtain modified activated carbon.

[0067] In the present invention, through acidic pretreatment, the concentration of oxygen-containing functional groups such as carboxyl groups and phenolic hydroxyl groups on the surface of activated carbon is increased, and the surface activity is improved; through the modification with silane coupling agent, a silicon-oxygen network with multi-point bonding is formed, and the amino group is firmly fixed on the surface of activated carbon, providing adsorption sites for silicon compounds, sulfides, etc.; further, through the formation of a triazine ring structure formed by the pyrolysis and condensation of melamine, a covalent bond is formed with the activated carbon substrate through a condensation reaction. In the modified activated carbon, a coordination bond is formed between the amino group and the silicon compound, and the conjugated system of the triazine ring has a π-π interaction with aromatic organosilicon compounds, aromatic sulfides, etc., enhancing the selective adsorption of hydrophobic silicon compounds. The embedding of the triazine ring can further regulate the pore size distribution of activated carbon to form channels mainly composed of mesopores, promoting the diffusion and adsorption of macromolecular silicon compounds, and being beneficial to the diffusion and adsorption of silicon compounds of different sizes.

[0068] Further, in step S2, the temperature of the low-temperature hydrogenation effluent is raised to 340 - 360°C after secondary preheating; the hydrofining reaction uses a hydrofining reactor 10, the inlet operating temperature of the hydrofining reactor 10 is 320 - 360°C, the operating pressure is 10.0 - 18.0 MPa(G), and the volumetric space velocity of the hydrofining catalyst is 0.5 - 2.0 h -1 .

[0069] In step S3, before the cracking reaction product is subjected to hot high-pressure separation treatment, it further includes: cooling the cracking reaction product to 250 - 270°C; the hot high-pressure separation treatment is carried out using a hot high-pressure separator 13, and the process parameters of the hot high-pressure separator 13 include: the stripping internal component uses a sieve tray or a floating valve tray, and the flow rate of the hot hydrogen is 10 - 25% of the recycle hydrogen flow rate; the temperature of the hot hydrogen is 20 - 30°C higher than the temperature of the reaction product.

[0070] In the present invention, in step S1, it is initially preheated to 110 - 120°C to reduce the viscosity of the pyrolysis oil, facilitating filtration and transportation; in step S2, the low-temperature hydrogenation effluent is heated to 340 - 360°C, and desiliconization, metal removal, and diolefin saturation are specifically carried out in the low-temperature reactor 7 to avoid the formation of gums and carbon deposits by these substances at high temperatures; after the cracking reaction, the temperature is controlled at 250 - 270°C, considering the characteristics of NH 4 Cl and NH 4 HS. Through the synergistic effect of temperature control and staged continuous injection of the alkaline solution, the risk of subsurface corrosion caused by the crystallization of NH 4 Cl and NH 4 HS is effectively reduced; it is further heated to 340 - 360°C to provide the high-temperature conditions required for hydrofining and mild cracking, and to achieve in-depth treatment such as desulfurization, denitrification, deoxidation, and saturation of unsaturated hydrocarbons.

[0071] 9 layers of sieve tray stripping internal components are provided in the hot high-pressure separator, and countercurrent stripping is carried out using hot hydrogen at 280°C (the flow rate is 10% - 25% of the recycle hydrogen), so that the removal rate of light components in the reaction product is increased and the carry-over amount of hydrogen chloride is reduced; the high-temperature hydrogen provides the stripping heat source, avoiding the enrichment of corrosive media caused by low-temperature condensation and reducing the equipment corrosion risk.

[0072] Further, before the first gas-phase condensation treatment and before the third gas-phase condensation treatment, both include staged continuous injection of an alkaline solution treatment, and the alkaline solution is one or more of Na 2 CO 3 solution, NaOH solution, KOH solution, and ammonia water.

[0073] Specifically, an alkaline solution is continuously injected in a graded manner before the first gas-phase condensation treatment: after the first gas phase is discharged from the gas-phase outlet of the hot high-pressure separator 13 and enters before the second heat exchanger 6, and after the first gas phase passes through the second heat exchanger 6 and enters before the hot high-pressure gas air cooler 14, an alkaline solution is injected. An alkaline solution is continuously injected in a graded manner before the third gas-phase condensation treatment: after the third gas phase is discharged from the gas-phase outlet of the hot low-pressure separator 19 and enters before the fifth heat exchanger 20, and after the third gas phase passes through the fifth heat exchanger 20 and enters before the hot low-pressure gas air cooler 21, an alkaline solution is injected.

[0074] The main purpose of injecting the alkaline solution is that under weakly alkaline conditions, the corrosion of the equipment pipeline by chloride ions is controllable. The alkaline solution is preferably used alone. More preferably, a low-concentration NaOH or KOH solution is selected, and preferably a NaOH solution.

[0075] The working principle of the present invention:

[0076] The full-fraction waste tire pyrolysis oil from the raw material tank area enters the first-stage filter 1 for filtration, and then enters the first heat exchanger 2 for heat exchange to 110 - 120 °C, passes through the second-stage filter 3 for filtration, then is boosted in pressure by the reaction feed pump 5, and then is mixed with the hydrogenated hydrogen from the supplementary hydrogen system in the pipeline. After heat exchange with the reaction product in the second heat exchanger 6 to 150 - 180 °C, it enters the low-temperature section hydrogenation reactor to remove silicon, metals, diolefins, etc.

[0077] The outlet stream of the low-temperature section hydrogenation reactor enters the third heat exchanger 8 through the pipeline for heat exchange with the reaction product from the reforming reactor 12, and then is heated to 340 - 360 °C in the reaction feed heating furnace 9 and enters the refining reactor 10. In the refining reactor 10, chlorine, sulfur, nitrogen, oxygen, and saturated and unsaturated hydrocarbons are removed. The outlet stream of the refining reactor 10 enters the fourth heat exchanger 11 through the pipeline for heat exchange with the hydrogenated hydrogen from the fifth heat exchanger 20, and then enters the reforming reactor 12 for a mild cracking reaction. Then it is heat-exchanged to 250 - 270 °C in the third heat exchanger 8, and then enters the upper middle part of the hot high-pressure separator 13 through the pipeline. A separation internal part is provided in the hot high-pressure separator 13. The hot hydrogenated hydrogen led out from the fourth heat exchanger 11 enters the lower middle part of the hot high-pressure separator 13. The separated gas phase enters the tube side of the second heat exchanger 6 through the pipeline, and an alkaline solution is injected near the tube side inlet of the second heat exchanger 6, and the pH value of the aqueous phase is controlled within the range of 7.5 - 9.0. Then it is condensed and cooled to 45 - 50 °C in the hot high-pressure gas air cooler 14 and enters the cold high-pressure separator 15 for gas, oil, and water separation. An alkaline solution is injected near the inlet of the hot high-pressure separator air cooler, and the pH value of the aqueous phase is controlled within the range of 7.5 - 9.0. The gas phase at the outlet of the cold high-pressure separator 15 is further separated and then enters the recycle hydrogen desulfurization tower 16 to remove hydrogen sulfide in the recycle hydrogen. The oil phase enters the cold low-pressure separator 22, and the aqueous phase is sulfur-containing sewage containing chlorine, ammonia, and hydrogen sulfide, which is discharged from the hydrogen-containing system.

[0078] After desulfurization, the recycled hydrogen is boosted in pressure by the recycle hydrogen compressor 17 and then mixed with the make-up hydrogen from the make-up hydrogen system to serve as the hydrogenated mixed gas for the hydrogenation reaction system. The reaction product fractionation system 23 fractionates naphtha, low-freezing-point diesel components, and tail oil.

[0079] As can be seen from Table 1, the sulfur content, nitrogen content, chlorine content, silicon + calcium content, bromine number, and acid value of waste tire pyrolysis oil are all factors that must be considered in the deep processing of waste tire pyrolysis oil. The present invention provides a method for tandem hydrotreating waste tire pyrolysis oil in view of its characteristics.

[0080] Table 1 Typical properties of waste tire pyrolysis oil

[0081]

[0082]

[0083] The technical solution of the present invention will be further described below through specific embodiments.

[0084] Example 1

[0085] This example provides a method for tandem hydrotreating waste tire pyrolysis oil, including the following steps:

[0086] S1. Perform primary filtration, initial heating, and secondary filtration on the waste tire pyrolysis oil. The filtration accuracy of the primary filtration is 80 μm, the filtration accuracy of the secondary filtration is 25 μm, and the temperature of the waste tire pyrolysis oil after initial heating is 105 °C; then mix the pretreated waste tire pyrolysis oil with the mixed hydrogen and preheat it to 150 °C for the first stage, and then enter the low-temperature reactor. The inlet operating temperature of the low-temperature reactor is 150 °C, the operating pressure is 13.0 MPa (G), the volume hourly space velocity of the desiliconizing agent is 6.0 h -1 , the volume hourly space velocity of the protective agent is 2.0 h -1 , the volume hourly space velocity of the main catalyst is 2.0 h -1 , and the hydrogen-oil volume ratio is 1000:1 Nm 3 / m 3 ;

[0087] Among them, the desiliconizing agent is modified activated carbon, the protective agent is silica, and the main catalyst is a nickel-based alumina catalyst; the preparation method of the modified activated carbon includes:

[0088] A1. Place 18 g of activated carbon in a 3 M hydrochloric acid solution, stir and react at 25 - 30 °C for 2.5 h, let it stand for 30 minutes and then filter to collect the solid. Mix 18 g of the pretreated activated carbon with 180 ml of anhydrous toluene, disperse it ultrasonically for 30 min, add 10 g of aminopropyltriethoxysilane (dissolved in 50 ml of toluene), and reflux and react at 110 °C for 7 h under nitrogen protection. After the reaction, cool, filter, wash, and dry to obtain silane-modified activated carbon.

[0089] A2. Dissolve 3 g of melamine in 200 mL of ethanol, add 10 g of silane-modified activated carbon, disperse it ultrasonically for 30 min, then dry and evaporate the ethanol. Transfer the dried mixture to a quartz boat in a tubular furnace, purge with nitrogen for 30 min to displace air, heat up to 330 °C at a heating rate of 5 °C / min, and react for 1.5 h. After the reaction, cool, wash, and dry to obtain modified activated carbon.

[0090] S2. The low-temperature hydrogenation effluent is preheated to 340 °C in two stages and then undergoes a hydrofining reaction. The inlet operating temperature of the hydrofining reactor is 340 °C, the operating pressure is 12.0 MPa(G), the volume hourly space velocity of the hydrofining catalyst is 1.0 h -1 , and the hydrogen-to-oil volume ratio is 800:1 Nm 3 / m 3 ; The obtained hydrofining effluent undergoes a mild cracking reaction. Among them, the inlet operating temperature of the reforming reactor is 330 °C, the volume hourly space velocity of the hydro-upgrading catalyst is 3.0 h -1 , and the hydrogen-to-oil volume ratio is 800:1 Nm 3 / m 3 ;

[0091] S3. Cool the cracking reaction product to 250 °C, and obtain the first gas phase and the first liquid phase through thermal high-pressure separation. The temperature of the thermal high-pressure separator is 250 °C, and the stripping internals of the thermal high-pressure separator are equipped with 9 sieve trays. The flow rate of the hot hydrogen is generally 10% (volume ratio) of the recycle hydrogen flow rate, and the temperature of the hot hydrogen is 280 °C;

[0092] S4. After the first gas phase is condensed, it undergoes cold high-pressure separation to obtain the second gas phase and the second liquid phase. The second gas phase is desulfurized to obtain recycle hydrogen, and the second liquid phase undergoes cold low-pressure separation to collect the oil phase; The first liquid phase undergoes thermal low-pressure separation to obtain the third gas phase and the third liquid phase. After the third gas phase is condensed, it undergoes cold low-pressure separation to collect the oil phase; Inject a NaOH solution with a pH of 10.0 at the inlets of the second heat exchanger tube side, the fifth heat exchanger tube side, the hot high-pressure gas air cooler, the hot low-pressure gas air cooler, etc., to ensure that after injecting the NaOH solution at each location, at least 25% (mass ratio) of the water phase flow rate at this position is not vaporized, and the pH value of the water phase is 7.5 - 9.0;

[0093] S5. The third liquid phase and the oil phase are mixed for fractional distillation of the reaction product to obtain naphtha, low-freezing-point diesel components and tail oil.

[0094] Example 2

[0095] This example provides a method for tandem hydrotreating of waste tire pyrolysis oil, which includes the following steps:

[0096] S1. The waste tire pyrolysis oil is subjected to primary filtration, initial heating and secondary filtration. The filtration accuracy of the primary filtration is 50 μm, and the filtration accuracy of the secondary filtration is 20 μm. The temperature of the waste tire pyrolysis oil after initial heating is 110 °C; then the pretreated waste tire pyrolysis oil and mixed hydrogen are mixed and preheated to 160 °C in the first stage and enter the low-temperature reactor. The inlet operating temperature of the low-temperature reactor is 160 °C, the operating pressure is 17.4 MPa(G), the volume hourly space velocity of the desiliconizing agent is 5.0 h -1 , the volume hourly space velocity of the protective agent is 1.0 h -1 , the volume hourly space velocity of the main catalyst is 4.0 h -1 , the hydrogen-oil volume ratio is 800:1 Nm 3 / m 3 ;

[0097] Among them, the desiliconizing agent is modified activated carbon, the protective agent is silica, and the main catalyst is a nickel-based alumina catalyst; the preparation method of the modified activated carbon includes:

[0098] A1. 15 g of activated carbon is placed in a 3M hydrochloric acid solution and stirred at 25 °C for 3 h, then left to stand for 30 minutes and filtered to collect the solid; 15 g of the pretreated activated carbon is mixed with 150 ml of anhydrous toluene and ultrasonically dispersed for 30 min, 10 g of aminopropyltriethoxysilane (dissolved in 50 ml of toluene) is added, and under nitrogen protection, the mixture is refluxed at 100 °C for 8 h. After the reaction is completed, it is cooled, filtered, washed and dried to obtain silane-modified activated carbon;

[0099] A2. 2 g of melamine is dissolved in 200 mL of ethanol, 10 g of silane-modified activated carbon is added, and ultrasonically dispersed for 30 min, then the ethanol is evaporated by drying. The dried mixture is transferred to a quartz boat in a tubular furnace, and nitrogen is introduced to displace the air for 30 min, and then heated to 300 °C at a heating rate of 5 °C / min and reacted for 2 h. After the reaction is completed, it is cooled, washed and dried to obtain modified activated carbon.

[0100] S2. The low-temperature hydrogenation effluent is preheated to 350 °C in the second stage and then undergoes hydrofining reaction. The inlet operating temperature of the hydrofining reactor is 350 °C, the operating pressure is 17.0 MPa(G), the volume hourly space velocity of the hydrofining catalyst is 2.0 h -1 , the hydrogen-oil volume ratio is 1000:1 Nm 3 / m 3; The obtained hydrofined effluent is subjected to mild cracking reaction. Among them, the inlet operating temperature of the reforming reactor is 340 °C, and the volume hourly space velocity of the hydrotreating catalyst is 4.0 h -1 , and the hydrogen-oil volume ratio is 1000:1 Nm 3 / m 3 ;

[0101] S3. Cool the cracking reaction product to 260 °C, and obtain the first gas phase and the first liquid phase through hot high-pressure separation treatment. The temperature of the hot high-pressure separator is 260 °C, and the stripping internals of the hot high-pressure separator are provided with 9 sieve trays. The flow rate of the hot hydrogen is generally 10% (volume ratio) of the recycle hydrogen flow rate, and the temperature of the hot hydrogen is 290 °C;

[0102] S4. After the first gas phase is condensed, it is subjected to cold high-pressure separation treatment to obtain the second gas phase and the second liquid phase. The second gas phase is subjected to desulfurization treatment to obtain recycle hydrogen, and the second liquid phase is subjected to cold low-pressure separation treatment to collect the oil phase; the first liquid phase is subjected to hot low-pressure separation treatment to obtain the third gas phase and the third liquid phase. After the third gas phase is condensed, it is subjected to cold low-pressure separation treatment to collect the oil phase; an NaOH solution with a pH of 10.0 is injected at the inlets of the second heat exchanger tube side, the fifth heat exchanger tube side, the hot high-pressure gas air cooler, the hot low-pressure gas air cooler, etc., to ensure that at least 25% (mass ratio) of the water phase flow rate at each position where the NaOH solution is injected is not vaporized, and the pH value of the water phase is 7.5 - 9.0;

[0103] S5. The third liquid phase and the oil phase are mixed for reaction product fractionation treatment to obtain naphtha, low-freezing-point diesel components and tail oil.

[0104] Example 3

[0105] This example provides a method for tandem hydrotreating waste tire pyrolysis oil, including the following steps:

[0106] S1. Perform primary filtration, primary heating and secondary filtration treatment on the waste tire pyrolysis oil. The filtration accuracy of the primary filtration is 100 μm, the filtration accuracy of the secondary filtration is 30 μm, and the temperature of the waste tire pyrolysis oil after primary heating is 120 °C; then the pretreated waste tire pyrolysis oil and mixed hydrogen are mixed and preheated to 180 °C for the first time, and enter the low-temperature reactor. The inlet operating temperature of the low-temperature reactor is 180 °C, the operating pressure is 10.0 MPa(G), the volume hourly space velocity of the desiliconizing agent is 4.0 h -1 , the volume hourly space velocity of the protective agent is 3.0 h -1 , the volume hourly space velocity of the main catalyst is 3.0 h -1 , and the hydrogen-oil volume ratio is 500:1 Nm 3 / m 3 ;

[0107] Among them, the desilicifying agent is modified activated carbon, the protective agent is silica, and the main catalyst is a nickel-based alumina catalyst; the preparation method of the modified activated carbon includes:

[0108] A1. Place 20 g of activated carbon in a 3M hydrochloric acid solution and stir and react at 30 °C for 2 h. After standing for 30 min, filter and collect the solid; mix 20 g of pretreated activated carbon with 200 ml of anhydrous toluene, ultrasonically disperse for 30 min, add 10 g of aminopropyltriethoxysilane (dissolved in 50 ml of toluene), and under nitrogen protection, reflux and react at 120 °C for 6 h. After the reaction is completed, cool, filter, wash, and dry to obtain silane-modified activated carbon;

[0109] A2. Dissolve 4 g of melamine in 200 mL of ethanol, add 10 g of silane-modified activated carbon, ultrasonically disperse for 30 min, then dry and evaporate the ethanol. Transfer the dried mixture to a quartz boat in a tubular furnace, introduce nitrogen to displace air for 30 min, and heat up to 350 °C at a heating rate of 5 °C / min and react for 1 h. After the reaction is completed, cool, wash, and dry to obtain modified activated carbon.

[0110] S2. The low-temperature hydrogenation effluent is preheated to 360 °C in two stages and then undergoes a hydrofining reaction. The inlet operating temperature of the hydrofining reactor is 360 °C, the operating pressure is 10.0 MPa(G), and the volume hourly space velocity of the hydrofining catalyst is 0.5 h -1 , and the hydrogen-oil volume ratio is 500:1 Nm 3 / m 3 ; the obtained hydrofining effluent undergoes a mild cracking reaction. Among them, the inlet operating temperature of the reforming reactor is 350 °C, the volume hourly space velocity of the hydrocracking catalyst is 6.0 h -1 , and the hydrogen-oil volume ratio is 500:1 Nm 3 / m 3 ;

[0111] S3. Cool the cracking reaction product to 270 °C and obtain the first gas phase and the first liquid phase through thermal high-pressure separation treatment. The temperature of the thermal high-pressure separator is 270 °C, and the stripping internal part of the thermal high-pressure separator is provided with 9 sieve trays. The flow rate of the hot hydrogen is generally 10% (volume ratio) of the circulating hydrogen flow rate. The temperature of the hot hydrogen is 280 °C;

[0112] S4. After the first gas phase condenses, it undergoes cold high-pressure separation to obtain a second gas phase and a second liquid phase. The second gas phase is subjected to desulfurization treatment to obtain recycled hydrogen, and the second liquid phase is subjected to cold low-pressure separation to collect the oil phase; the first liquid phase is subjected to hot low-pressure separation to obtain a third gas phase and a third liquid phase. After the third gas phase condenses, it is subjected to cold low-pressure separation to collect the oil phase; an NaOH solution with a pH of 10.0 is injected at the inlets of the tube side of the second heat exchanger, the tube side of the fifth heat exchanger, the hot high-pressure gas air cooler, the hot low-pressure gas air cooler, etc., to ensure that after injecting the NaOH solution at each location, at least 25% (by mass) of the water phase flow rate at this position is not vaporized, and the pH value of the water phase is 7.5 - 9.0;

[0113] S5. The third liquid phase and the oil phase are mixed for reaction product fractionation to obtain naphtha, low-freezing-point diesel components, and tail oil.

[0114] Comparative Example 1

[0115] This comparative example provides a method for tandem hydrotreating waste tire pyrolysis oil. The steps are the same as those in Example 1, except that: the desiliconizing agent is silane-modified activated carbon, and the preparation method includes:

[0116] Place 18 g of activated carbon in a 3M hydrochloric acid solution and stir and react at 25 - 30 °C for 2.5 h. After standing for 30 minutes, filter and collect the solid; mix 18 g of pretreated activated carbon with 180 ml of anhydrous toluene, ultrasonically disperse for 30 min, add 10 g of aminopropyltriethoxysilane (dissolved in 50 ml of toluene), and under nitrogen protection, reflux and react at 110 °C for 7 h. After the reaction is completed, cool, filter, wash, and dry to obtain silane-modified activated carbon.

[0117] Comparative Example 2

[0118] This comparative example provides a method for tandem hydrotreating waste tire pyrolysis oil. The steps are the same as those in Example 1, except that: the desiliconizing agent is modified activated carbon, and the preparation method includes:

[0119] Dissolve 3 g of melamine in 200 mL of ethanol, add 10 g of activated carbon, ultrasonically disperse for 30 min, then dry and evaporate the ethanol. Transfer the dried mixture to a quartz boat in a tube furnace, purge with nitrogen for 30 min, and heat up to 330 °C at a heating rate of 5 °C / min and react for 1.5 h. After the reaction is completed, cool, wash, and dry to obtain modified activated carbon.

[0120] Comparative Example 3

[0121] This comparative example provides a method for tandem hydrotreating waste tire pyrolysis oil. The steps are the same as those in Example 1, except that: no alkaline solution is injected before the first gas phase condenses and before the third gas phase condenses.

[0122] The properties of the refined naphtha, refined diesel, and tail oil of the hydrogenation reaction products of the examples and comparative examples through the reaction product fractionation system are shown in Tables 2 and 3.

[0123] Table 2 Examples

[0124]

[0125] Table 3

[0126]

[0127] As can be seen from Tables 2 and 3, the technical solution of the present invention can significantly reduce the chlorine content, sulfur content, and nitrogen content of waste tire pyrolysis oil, improve the adsorption efficiency, and reduce the risk of chlorine corrosion of facilities such as pipelines of subsequent deep processing equipment for waste tire pyrolysis oil.

[0128] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for serially hydrotreating waste tire pyrolysis oil, characterized in that: include: S1, mixing the pretreated waste tire pyrolysis oil and mixed hydrogen, and then preheating them in one stage, and performing low-temperature hydrogenation treatment; S2, the low temperature hydrogenation effluent is subjected to a hydrotreating reaction after secondary preheating, and the obtained hydrotreating effluent is subjected to a shallow cracking reaction; S3, subjecting the cracking reaction product to a thermal high-pressure separation treatment to obtain a first gas phase and a first liquid phase; S4, the first gas phase is condensed and subjected to cold high-pressure separation treatment to obtain a second gas phase and a second liquid phase, the second gas phase is subjected to desulfurization treatment to obtain circulating hydrogen, and the second liquid phase is subjected to cold low-pressure separation treatment to collect an oil phase; The first liquid phase is subjected to hot low-pressure separation treatment to obtain a third gas phase and a third liquid phase, and the third gas phase is condensed and subjected to cold low-pressure separation treatment to collect an oil phase; S5. The third liquid phase and the oil phase are mixed to perform reaction product fractionation treatment to obtain naphtha, low-freezing point diesel components and tail oil.

2. A method for tandem hydrotreating of waste tire pyrolysis oil as claimed in claim 1, characterized in that: In step S1, the pretreatment includes sequentially performing primary filtration, primary heating and secondary filtration on the waste tire pyrolysis oil. The filtration accuracy of the primary filtration is 50-100 μm, the filtration accuracy of the secondary filtration is 20-30 μm, and the temperature of the waste tire pyrolysis oil after the primary heating is 110-120°C.

3. A method for tandem hydrotreating of waste tire pyrolysis oil as claimed in claim 1, characterized in that: In step S1, low-temperature hydrogenation treatment is carried out in a low-temperature reactor, the reactor inlet operating temperature is 150-180°C, the operating pressure is 10.0-18.0 MPa (G), and the volume space velocity of the desiliconizing agent is 4.0-6.0 h -1 , protective agent volume space velocity 1.0-3.0h -1 , main catalyst volume space velocity 2.0-4.0h -1 , hydrogen oil volume ratio is 500:1-1000:1Nm 3 / m 3 .

4. A method for tandem hydrotreating of waste tire pyrolysis oil as claimed in claim 3, characterized in that: The desiliconizing agent is modified activated carbon, the protective agent is silicon dioxide and / or aluminum oxide, and the main catalyst is a nickel-based aluminum oxide catalyst and / or a molybdenum-based aluminum oxide catalyst.

5. A method for serially hydrotreating waste tire pyrolysis oil as claimed in claim 4, characterized in that: The preparation method of the modified activated carbon comprises: A1. Pre-treating activated carbon in an acidic solution, mixing the pre-treated activated carbon with 3-aminopropyltriethoxysilane in anhydrous toluene, and subjecting the mixture to reflux reaction at 100-120° C. for 6-8 hours to obtain silane-modified activated carbon; A2. Mix the silane-modified activated carbon with melamine, and heat-treat at 300-350° C. for 1-2 h under nitrogen protection to obtain modified activated carbon.

6. A method for tandem hydrotreating of waste tire pyrolysis oil as claimed in claim 1, characterized in that: In step S2, the temperature of the low-temperature hydrogenation effluent is raised to 340-360°C after secondary preheating; the hydrofining reaction adopts a refining reactor, the inlet operating temperature of the refining reactor is 320-360°C, the operating pressure is 10.0-18.0MPa(G), and the volume space velocity of the hydrofining catalyst is 0.5-2.0h -1 .

7. A method for tandem hydrotreating of waste tire pyrolysis oil as claimed in claim 1, characterized in that: Shallow cracking uses a reforming reactor with an inlet operating temperature of 330-350°C and a volume space velocity of 3.0-6.0 h-1 for the hydrogenation reforming catalyst. -1 , hydrogen oil volume ratio is 500:1-1000:1Nm 3 / m 3 .

8. A method for tandem hydrotreating of waste tire pyrolysis oil as claimed in claim 1, characterized in that: In step S3, before the cracking reaction product is subjected to hot high-pressure separation treatment, the cracking reaction product is cooled to 250-270°C; the hot high-pressure separation treatment is carried out using a hot high-pressure separator, and the process parameters of the hot high-pressure separator include: the stripping internals use a sieve tray or a float valve tray, the flow rate of hot hydrogen is 10-25% of the circulating hydrogen flow rate; the temperature of the hot hydrogen is 20-30°C higher than the temperature of the reaction product.

9. A method for tandem hydrotreating of waste tire pyrolysis oil as claimed in claim 1, characterized in that: Both the first gas phase condensation treatment and the third gas phase condensation treatment include graded continuous injection of alkaline solution treatment, wherein the alkaline solution is one or more of Na2CO3 solution, NaOH solution, KOH solution, and ammonia water.

10. A system for serially hydrotreating waste tire pyrolysis oil, characterized in that: The system is used to implement a method for serially hydrotreating waste tire pyrolysis oil according to any one of claims 1 to 9, and the system comprises: A pretreatment module, used for pretreatment of waste tire pyrolysis oil, comprising at least a primary filter and a set of heat exchangers; A low-temperature hydrogenation module is used for low-temperature hydrogenation treatment of preheated waste tire pyrolysis oil, and comprises at least two sets of low-temperature hydrogenation reactors connected in parallel; A hydrofining and reforming module, which is used for refining, hydrogenation and cracking of low-temperature hydrogenation effluent, and includes a refining reactor and a reforming reactor connected in series; A separation and purification module, used for separating and treating the cracking reaction products, comprises a hot high-pressure separator, a cold high-pressure separator, a hot low-pressure separator and a cold low-pressure separator, wherein the feed inlet of the hot high-pressure separator is connected to the reforming reactor, the liquid phase outlet is connected to the hot low-pressure separator, and the gas phase outlet is connected to the cold high-pressure separator; the gas phase outlet of the hot low-pressure separator and the oil phase outlet of the cold high-pressure separator are respectively connected to the cold low-pressure separator; A reaction product fractionation module is used to fractionate the liquid phase product of the hot low-pressure separator and the oil phase product of the cold low-pressure separator; The circulating hydrogen mixing module is used to recover and process the hydrogen in the separated gas phase and supply it to the low-temperature hydrogenation module and the hydrotreating and reforming module.

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