Tire pyrolysis oil fractionation method

Abstract

The invention provides a tire pyrolysis oil fractionation method, and relates to the technical field of chemical separation. Tire pyrolysis oil needs to be modified and upgraded due to the defects of high sulfur content, large viscosity and the like, and an existing modification method has the problems of harsh reaction conditions, high cost and the like. The method comprises the following steps: diluting the tire pyrolysis oil, putting the diluted tire pyrolysis oil into a feeding device, adjusting system pressure and molecular distillation equipment parameters for separation, recovering part of escapes through secondary condensation and cold trap condensation, and evaporating out a diluent by using a rotary evaporator to obtain light and heavy distillate oil. According to the method, efficient separation and nondestructive collection can be achieved, the modification effect and economic value of the pyrolysis oil are improved, and waste tire treatment modes are increased.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical separation, and in particular relates to a tire pyrolysis oil graded separation method. Background Art

[0002] Waste Tire Pyrolysis Oil (WTPO) is rich in aromatic hydrocarbons such as benzene, toluene, xylene, limonene, etc. It has the characteristics of high calorific value and can be used as an alternative to fossil fuels. It is a high value-added chemical raw material. However, the high sulfur content (0.6-1.6%), high viscosity, and low flash point of WTPO restrict its direct use as fuel, so further upgrading of WTPO is needed.

[0003] At present, the main modification method used in tire pyrolysis oil is hydrodesulfurization. In the hydrodesulfurization process, precious metals (such as Pt, Ru, Ni) and transition metals (such as Co, Mo) are usually used as catalysts. Under certain H2 partial pressure and high temperature conditions, heteroatoms such as N and S in tire pyrolysis oil are removed, and olefins are converted into saturated hydrocarbons. Oxidative desulfurization is the oxidation of heterocyclic sulfides in tire pyrolysis oil into sulfones under the joint action of catalysts and oxidants, and then separated by extractants or removed by adsorbents. Although these methods can improve the performance of tire pyrolysis oil, the modification of all components is restricted due to harsh reaction conditions, high costs, and possible problems such as easy carbon deposition and catalyst deactivation.

[0004] Therefore, in order to further improve the quality of tire pyrolysis oil, the composition of different fractions of tire pyrolysis oil can be changed by distillation, and then targeted modification treatment is carried out for different components to improve the modification efficiency of tire pyrolysis oil. Conventional distillation methods include atmospheric distillation, vacuum distillation, steam distillation and flash distillation. Atmospheric distillation is a process of separating the components in a mixture by using the relative volatility differences, which is completed under pressure conditions close to atmospheric pressure. Vacuum distillation is suitable for the separation and purification of compounds that have been thermally decomposed, oxidized or polymerized before reaching the boiling point during atmospheric distillation. Atmospheric distillation and vacuum distillation have the advantages of simple operation and low cost, but there is a problem of long residence time, which destroys the composition of crude oil and affects the yield of distillate oil. Steam distillation makes the separated substances boil at a temperature lower than the original boiling point, which is suitable for substances that are immiscible with water and easily decomposed at higher temperatures. Flash distillation is to partially vaporize the separated substances, thereby achieving vapor-liquid separation. The separation process of steam distillation and flash distillation has a short residence time, which avoids the occurrence of secondary reactions, but is only suitable for low-purity pre-separation. Molecular distillation can achieve the function of fractionation by utilizing the differences in the mean free paths of different molecules. However, tire pyrolysis oil contains a variety of hydrocarbon compounds, including saturated hydrocarbons, unsaturated hydrocarbons, aromatic hydrocarbons, etc. It may also contain compounds with heteroatoms such as sulfur and nitrogen, as well as a small amount of residual additives. The molecular structures and properties of each component are quite different, which makes the mean free paths of molecular motion of different components overlap with each other, increasing the difficulty of precise fractionation and separation using molecular distillation.

[0005] Therefore, it is necessary to propose a molecular distillation fractionation method for carrying out efficient and high-yield separation of tire pyrolysis oil. Summary of the invention

[0006] In order to overcome the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a tire pyrolysis oil fractionation separation method, which realizes efficient separation of light fraction and heavy fraction through the fine design of the molecular distillation process.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for fractionating and separating tire pyrolysis oil, comprising the following steps: 1) Using tire pyrolysis oil as raw material, diluting the tire pyrolysis oil, and putting the diluted tire pyrolysis oil into the system feeding device; 2) adjusting the system pressure and molecular distillation equipment parameters, including the heating temperature, molecular distillation condensation temperature, distillation pressure and scraper speed, and after all parameters are stable, opening the sample valve of the feed device to allow the diluted tire pyrolysis oil to enter the molecular distillation device for separation to obtain diluted light distillate oil and diluted heavy distillate oil; 3) removing the diluent in the diluted light distillate oil and the diluted heavy distillate oil, so as to obtain the light distillate oil and the heavy distillate oil of the tire pyrolysis oil; The heating temperature is 100-160° C., the molecular distillation condensation temperature is -12--8° C., the distillation pressure is 115-125 Pa, and the scraper speed is 40-50 r / min.

[0008] Preferably, the diluent used is dichloromethane.

[0009] Further preferably, the ratio of the amount of the dichloromethane to the amount of the tire pyrolysis oil is 1:1.

[0010] Preferably, in 2), part of the diluted light fraction oil escaping from the molecular distillation device during the molecular distillation process is recovered after secondary condensation and cold trap condensation.

[0011] Preferably, the refrigerant used in the cold trap is a mixture of anhydrous ethanol and dry ice.

[0012] Preferably, in 2), the condensing medium used in the molecular distillation process is a mixture of ethylene glycol and water.

[0013] Preferably, the volume ratio of the ethylene glycol to water is (50-60):(50-40).

[0014] Preferably, after the molecular distillation process is completed, a diluent is used to clean the inner wall of the molecular distiller to ensure that each fraction oil is completely collected.

[0015] Preferably, in the step 3), a rotary evaporator is used to completely evaporate the dichloromethane in each fraction oil.

[0016] Preferably, the tire pyrolysis oil is full-component pyrolysis oil of waste tires at 400°C.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The method for fractionating and separating tire pyrolysis oil proposed in the present invention adopts molecular distillation, and WTPO is separated into light distillate oil and heavy distillate oil by adjusting the evaporation temperature in the molecular distillation process, so that the separated light distillate oil and heavy distillate oil have good fluidity, ensuring the effective evaporation of light components and the efficient separation of tire pyrolysis oil. It also shows that molecular distillation can realize the fractionation and lossless collection of tire pyrolysis oil for subsequent upgrading and utilization.

[0018] The method proposed in the present invention can realize the reuse of molecular distillation technology in the field of waste tires, so as to increase the way of treating waste tires, separate tire pyrolysis oil into tire oil fractions with different characteristics, which is beneficial to expand the possibility of tire oil as liquid fuel, obtain high-value chemicals, and increase the economic value of tire pyrolysis oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a diagram of the WTPO fractionation separation device of the present invention; Figure 2 The total ion chromatograms of gas chromatography-mass analysis of waste tire pyrolysis oil at different temperatures; Figure 3 The total ion chromatograms of the gas chromatography-mass spectrometry of the light and heavy fractions of waste tire pyrolysis oil after molecular distillation at different temperatures; Among them: 1. Feeding device; 2. Material conveying device; 3. Evaporation device (with dimethyl silicone oil in the middle of the double-layer jacket); 4. Coupling motor device; 5. Scraper; 6. Primary condensing device; 7. Secondary condensing device; 8. Cold trap; 9. Cold trap collecting bottle; 10. Secondary condensing device collecting bottle; 11. Light fraction collecting bottle; 12. Heavy fraction collecting bottle; 13. High temperature circulator; 14. Low temperature constant temperature bath; 15. Low temperature coolant circulation pump; 16. VCT160 Pirani vacuum gauge and control device; 17. Vacuum device. DETAILED DESCRIPTION

[0020] In order to make the technical personnel in the technical field better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only an embodiment of a part of the present invention, not all embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work should belong to the scope of protection of the present invention. It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0021] The primary tire pyrolysis product - tire pyrolysis oil usually has problems in quality indicators, combustion performance and purity, so it must be modified before it can be better used in downstream industries.

[0022] In terms of oil quality indicators, tire pyrolysis oil usually contains a high level of sulfur, which will produce harmful gases such as sulfur dioxide when burned, seriously polluting the environment and not meeting environmental protection requirements. At the same time, high sulfur content will also lead to increased corrosion of equipment such as engines, reduce the service life of equipment, and affect the normal operation of downstream industries. Aromatics account for a large proportion of tire pyrolysis oil. Although aromatics have a high octane number, excessive aromatic content will increase the toxicity of oil products and cause harm to human health and the environment. Moreover, high aromatic content will affect the combustion performance of oil products, causing incomplete combustion, carbon deposits, and reducing engine efficiency and performance. Tire pyrolysis oil has poor chemical stability and is prone to oxidation, polymerization and other reactions during storage and use, causing the oil to darken in color, increase viscosity, produce precipitation and colloid, affect the fluidity and combustion performance of the oil products, and reduce its use value.

[0023] In terms of combustion performance, the cetane number of tire pyrolysis oil is generally low, which means that the ignition delay period is long and the combustion is incomplete, which will cause problems such as engine power reduction, fuel consumption increase, and emission deterioration when it is used as fuel. At the same time, the flash point of tire pyrolysis oil is relatively low, which makes it a major safety hazard during storage, transportation and use, and is prone to fire and explosion accidents, and does not meet relevant safety standards and specifications. Due to differences in the source and production process of tire pyrolysis oil, its calorific value fluctuates greatly. This will bring difficulties to the combustion control and energy supply of downstream industries, making it difficult to ensure the stable operation of equipment and the effective use of energy.

[0024] In terms of purity, tire pyrolysis oil may be mixed with some mechanical impurities during the production process, such as rubber particles, carbon black, etc. These impurities will clog the engine's fuel injectors, filters and other components, affecting the normal operation of the engine and increasing the maintenance cost of the equipment. Tire pyrolysis oil may contain a certain amount of water, which will reduce the calorific value of the oil and affect the combustion effect. At the same time, water will also cause equipment corrosion, and may freeze in low temperature environments, clogging pipes and filters, causing many problems for downstream industry applications.

[0025] Therefore, it is very necessary to modify WTPO. However, in view of the fact that WTPO has many defects in properties, the cost of its modification process through traditional hydrogenation or oxidation is high, or only a single property improvement can be achieved. Therefore, the present invention proposes a method for modifying WTPO, by first fractionating and separating WTPO, the first-level improvement of oil quality can be achieved at very low oil, and the effect of subsequent modification can be improved. Molecular distillation technology is a method in which the mean free path of vapor molecules is greater than the distance between the evaporation surface and the condensation surface under vacuum, thereby using the difference in evaporation rate of each component in the feed liquid to separate the liquid mixture. It is a useful and gentle method for separating and purifying heat-sensitive materials and those compounds with high relative molecular mass and low vapor pressure. This technology has the advantages of low operating temperature, high separation efficiency, and low environmental pollution. It is mainly used to separate high boiling point, high heat sensitivity, and easy oxidation systems, and the purity of the obtained product is higher than that of ordinary distillation methods. The principle is that the mean free path of different molecules is different, so the distance between different molecules and the liquid surface after overflow is also different. By increasing the temperature and reducing the pressure to increase the mean free path between molecules, the separation of light components and heavy components of the liquid can be achieved.

[0026] However, it is difficult to apply molecular distillation technology to the graded separation of tire pyrolysis oil. The main reason is that tire pyrolysis oil contains a variety of hydrocarbon compounds, including saturated hydrocarbons, unsaturated hydrocarbons, aromatic hydrocarbons, etc. It may also contain compounds with heteroatoms such as sulfur and nitrogen, as well as a small amount of additive residues. The molecular structure and properties of each component are quite different, which makes the molecular motion mean free paths of different components overlap with each other, increasing the difficulty of accurate graded separation using molecular distillation. In order to achieve effective graded separation of tire pyrolysis oil and obtain different fractions for different application fields, higher separation accuracy is often required. However, due to the complexity and mutual interference of pyrolysis oil components, in order to achieve the ideal separation effect, the design of molecular distillation equipment and the optimization of operating parameters are very demanding, and parameters such as distillation temperature, pressure, feed rate, and scraping speed need to be precisely controlled.

[0027] The method for fractionating and separating tire pyrolysis oil by molecular distillation proposed by the present invention specifically comprises the following steps: 1) Using tire pyrolysis oil as raw material, diluting the tire pyrolysis oil, and putting the diluted tire pyrolysis oil into the system feeding device; 2) adjusting the system pressure and molecular distillation equipment parameters, including heating temperature, molecular distillation condensation temperature, distillation pressure and scraper speed. After all parameters are stable, open the sample valve of the feeding device to allow the diluted tire pyrolysis oil to enter the molecular distillation device for separation to obtain diluted light distillate oil and diluted heavy distillate oil. The heating temperature is 100-160°C; the molecular distillation condensation temperature is -12°C-8°C, preferably -10°C; the distillation pressure is 115-125Pa, preferably 120Pa; the scraper speed is 40-50r / min, preferably 45 r / min; 3) removing the diluent in the diluted light distillate oil and the diluted heavy distillate oil, so as to obtain the light distillate oil and the heavy distillate oil of the tire pyrolysis oil; Tire pyrolysis oil has a complex composition and contains a variety of hydrocarbon compounds, including saturated hydrocarbons, unsaturated hydrocarbons, aromatic hydrocarbons, etc. It may also contain compounds with heteroatoms such as sulfur and nitrogen, as well as a small amount of additive residues. The molecular structures and properties of each component are quite different, which makes the molecular motion mean free paths of different components overlap with each other, increasing the difficulty of accurate fractionation and separation using molecular distillation. In order to achieve effective fractionation and separation and obtain different fractions for different application fields, higher separation accuracy is often required. However, due to the complexity and mutual interference of pyrolysis oil components, in order to achieve the ideal separation effect, the design of molecular distillation equipment and the optimization of operating parameters are very demanding, and it is necessary to accurately control parameters such as distillation temperature, pressure, feed rate, and scraping speed. The present invention performs molecular distillation at 100-160°C, the molecular distillation condensation temperature is -12°C--8°C, preferably -10°C; the distillation pressure is 115-125Pa, preferably 120Pa; the film scraper speed is 40-50r / min, preferably 45r / min; the tire pyrolysis oil is separated into a heavy fraction and a light fraction, a very high yield is achieved, the components of the tire pyrolysis oil are retained, and the graded separated light components and heavy components can be easily further reformed.

[0028] In some embodiments of the present invention, the diluent that can be used is petroleum ether, toluene, xylene, n-hexane or dichloromethane.

[0029] In some embodiments of the present invention, the ratio of the diluent to the tire pyrolysis oil is 1:1.

[0030] In some embodiments of the present invention, in 2), part of the diluted light distillate oil escaping from the molecular distillation device during the molecular distillation process is recovered after secondary condensation and cold trap condensation. Figure 1 In the device diagram, the secondary condensation device 7 and the cold trap 8 are arranged in series downstream of the evaporation device 3.

[0031] In the embodiment of the present invention, the refrigerant used in the cold trap 8 is a mixture of anhydrous ethanol and dry ice, which can achieve a lower condensation temperature of about -78°C, and perform a third-stage collection of the escaped light fraction to reduce the raw material loss of graded distillation.

[0032] In the embodiment of the present invention, in 2), the condensing medium used in the molecular distillation process is a mixture of ethylene glycol and water, and the condensing medium is filled in the primary condensing device 6 located in the middle of the evaporating device and used as a condensing plate for light components.

[0033] The evaporation device used in the present invention has a cylindrical barrel with a heating jacket (i.e., a heating device 3), a rotor and a built-in condenser (i.e., a primary condensation device 6); a film scraper and a splash-proof device (i.e., a film scraper 5) are attached to the rotor, the primary condenser 6 is located at the center of the barrel of the evaporator 3, and the rotor rotates between the barrel of the evaporator 3 and the primary condenser 6. The evaporator 3 is externally connected to a high-temperature circulator 13, and the heating medium is dimethyl silicone oil. The primary condensation device is externally connected to a low-temperature thermostatic tank 14, and the cooling medium is ethylene glycol and water. The light components flow from the condenser 6 into the light fraction collection bottle 11, and the remaining heavy fractions flow from the barrel of the evaporator 3 into the heavy fraction collection bottle.

[0034] The distillation process is as follows: the material is added from the top of the evaporator, and is continuously and evenly distributed on the heating surface by the liquid distributor on the rotor. Then the film scraper scrapes the liquid into a very thin, turbulent liquid film, and propels it downward in a spiral. In this process, the light molecules escaping from the heating surface condense into liquid on the built-in condenser through a short route and almost without collision, and flow down along the condenser tube and are discharged through the discharge pipe at the bottom of the evaporator; the residual liquid, that is, the heavy molecules, are collected in the circular channel under the heating zone and then flow out through the discharge pipe on the side.

[0035] The liquid mixture flows from top to bottom along the heating plate, and the molecules with sufficient energy escape from the liquid surface after being heated. A condensation plate is set at a distance from the liquid surface that is less than the molecular mean free path of light molecules but greater than the molecular mean free path of heavy molecules. The light molecules can reach the condensation plate, destroying the dynamic equilibrium of the light molecules in the system and escaping continuously. The heavy molecules cannot reach the condensation plate, and soon tend to dynamic equilibrium with the heavy molecules in the liquid phase. Apparently, the heavy molecules no longer escape from the liquid phase, and in this way, the liquid mixture is separated.

[0036] According to the principle of molecular distillation, under high vacuum conditions, when the mean free path of steam molecules is greater than the distance between the evaporation surface and the condensation surface, the liquid mixture can be separated by utilizing the difference in evaporation rates of the components in the liquid. The molecular mean free path formula is:

[0037] Where: λm , T , p , d and K They are the molecular mean free path, spatial temperature, spatial pressure, molecular effective diameter and Boltz-mann constant. It can be seen from the above formula that temperature, pressure and molecular effective diameter are factors that affect the mean free path of molecular motion. When the pressure is constant, the molecular mean free path of a certain substance increases with increasing temperature. Under the same pressure, the higher the temperature, the larger the effective diameter of the molecules reaching the condensation surface. Different substances have different molecular mean free paths due to their different effective diameters.

[0038] The molecular distillation evaporation system maintains a high vacuum degree, and the distance between the condensation surface and the evaporation surface should be the same as the mean free path of the evaporating molecules under a given pressure; to prevent the condensed molecules from re-evaporating, the temperature of the condensation surface should be 50~100℃ lower than the evaporation surface; the evaporated material should be able to form a film that is continuously updated, completely covered, and uniform in thickness on the evaporation surface, and the residence time of the material should be controlled to improve the evaporation efficiency and prevent the components from being destroyed. The mean free paths of light and heavy molecules must be different, and the greater the difference, the better.

[0039] The distance between the evaporation surface and the condensation surface must be less than the mean free path of light molecules. In fact, it is often very uneconomical for the distance between the evaporator surface and the condenser surface to be less than the mean free path of the molecules. Therefore, the distance is usually slightly greater than the mean free path of the molecules and is controlled within the same order of magnitude. In production, molecular distillation is usually operated at a pressure of 0.4~40Pa, and the other type, called unobstructed distillation, is usually operated at 2.7~66.7Pa. The plate spacing of unobstructed distillation is larger, and the plate spacing of molecular distillation is smaller. Short-path distillation generally refers to these two.

[0040] In an embodiment of the present invention, the primary condensing device and the secondary condensing device use a mixture of ethylene glycol and water as a condensing agent, and the volume ratio of ethylene glycol to water is (50~60):(50~40), preferably 55:45.

[0041] In the embodiment of the present invention, after the molecular distillation process is completed, a diluent is used to clean the inner wall of the molecular distiller to ensure that each fraction oil is completely collected.

[0042] In the embodiment of the present invention, in 3), a rotary evaporator is used to completely evaporate the dichloromethane in each fraction oil.

[0043] The present invention is described in further detail below in conjunction with embodiments: Firstly, waste tires were pyrolyzed at different pyrolysis temperatures, and the gas quality of all components of waste tire pyrolysis oil was analyzed. The analysis results are as follows: Figure 2As shown, it is the total ion chromatogram of the gas chromatography of waste tire pyrolysis oil at different pyrolysis temperatures. It can be seen from the figure that the component types and relative contents in the waste tire pyrolysis oil at different temperatures are significantly different. The higher the temperature, the more component types there are in the pyrolysis oil, and the higher the relative content is, but the relative content of light aromatics benzene, toluene, and xylene (BTX) is not high. The following embodiments of the present invention all take tire pyrolysis oil with a pyrolysis temperature of 400°C for graded separation.

[0044] Example 1 The tire pyrolysis oil was separated using an AYAN-F80-DZ molecular distillation instrument (Shanghai Guiyong Electronics Co., Ltd.). The parameters of the instrument were pre-set before the reaction. The heating liquid of the high-temperature circulator 13 was dimethyl silicone oil, and the heating temperature was set to 100°C; the condensing medium of the low-temperature thermostatic bath was a mixture of ethylene glycol and water (Vglycol / Vwater=55:45), and the primary condensation temperature and the secondary condensation temperature were set to -5°C and -10°C respectively; the distillation pressure was 120Pa; the cold hydrazine was added with a mixture of molten anhydrous ethanol and dry ice, and the temperature was about -78°C.

[0045] For a typical molecular distillation, the process is as follows: turn on the high temperature circulator and low temperature thermostat in advance, add anhydrous ethanol and dry ice mixture to the cold hydrazine, and wait until each parameter reaches the preset value. Mix 100g of tire pyrolysis oil obtained by cracking with 100ml of dichloromethane and pour it into the feeding device. Turn on the vacuum pump and adjust the system pressure. Adjust the speed of the scraper to 45r / min, slowly open the feed control valve and control the feed speed, and the sample begins to enter the jacketed evaporator. The tire pyrolysis oil is scraped into an extremely thin liquid film by the scraper, evenly covering the inner wall of the jacketed evaporator.

[0046] Under the dual effects of evaporation heating and vacuum, the components with smaller molecular mean free paths evaporate and escape, are condensed on the condensation device and the cold hydrazine device, and flow into the round-bottom flask of the light distillate oil. The components with larger molecular mean free paths that are not vaporized will flow into the inner wall of the jacketed evaporator and into the round-bottom flask of the heavy distillate oil. Some heavy distillate oil also adheres to the jacketed evaporator and the inner wall of the pipeline. After the distillation process is completed, it is rinsed twice with 100ml of dichloromethane to ensure that each distillate oil is completely collected. Subsequently, a rotary evaporator is used to completely evaporate the dichloromethane in each distillate oil. Since dichloromethane is added to the tire cracking oil to ensure its fluidity, and dichloromethane is used to rinse the device, it is necessary to rotate the light and heavy distillates separately to remove the dichloromethane therein.

[0047] Example 2 The heating temperature of the molecular distillation was set to 115° C., and the other parameters were the same as those in Example 1.

[0048] Example 3 The heating temperature of the molecular distillation was set to 130° C., and the other parameters were the same as those in Example 1.

[0049] Example 4 The heating temperature of the molecular distillation was set to 145° C., and the other parameters were the same as those in Example 1.

[0050] Example 5 The heating temperature of the molecular distillation was set to 160° C., and the other parameters were the same as those in Example 1.

[0051] Effect test Figure 3 The following table shows the total ion chromatograms of the gas chromatography-mass spectrometry of light and heavy distillate oils after molecular distillation of waste tire pyrolysis oil at different temperatures. The results show that the yield of light distillate oil increases significantly with the increase of temperature.

[0052]

[0053] In the above embodiment of the present invention, the light distillate oil yield range of WTPO at different distillation temperatures (100-160°C) under a pressure of 120Pa is 31.2wt.%-70.0wt.%, and the heavy distillate oil yield range is 27.8wt.%-67.5wt.%.

[0054] Molecular distillation can significantly increase the content of light aromatics in light distillate oil. The ketone content detected in light distillate oil is higher than WTPO, which is 4.90%-7.37%. By comparing the composition and content of the separated light distillate oil and heavy distillate oil, it can be seen that there is an obvious difference between the two. Subsequently, high-value applications can be carried out according to the different characteristics of the light and heavy components.

[0055] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A tire pyrolysis oil fractionation separation method, characterized in that: The following steps are involved: 1) Using tire pyrolysis oil as raw material, diluting the tire pyrolysis oil, and putting the diluted tire pyrolysis oil into the system feeding device; 2) adjusting the system pressure and molecular distillation equipment parameters, including the heating temperature, molecular distillation condensation temperature, distillation pressure and scraper speed, and after all parameters are stable, opening the sample valve of the feed device to allow the diluted tire pyrolysis oil to enter the molecular distillation device for separation, and collecting the diluted light distillate oil and the diluted heavy distillate oil; 3) removing the diluent in the diluted light distillate oil and the diluted heavy distillate oil, so as to obtain the light distillate oil and the heavy distillate oil of the tire pyrolysis oil; The heating temperature is 100-160° C., the molecular distillation condensation temperature is -12--8° C., the distillation pressure is 115-125 Pa, and the scraper speed is 40-50 r / min.

2. The tire pyrolysis oil fractionation separation method according to claim 1, characterized in that: In the above 1), the diluent used is dichloromethane.

3. The tire pyrolysis oil fractionation separation method according to claim 2, characterized in that: The ratio of the amount of the dichloromethane to the amount of the tire pyrolysis oil is 1:

1.

4. The tire pyrolysis oil fractionation separation method according to claim 1, characterized in that: In the above 2), part of the diluted light fraction oil escaping from the molecular distillation device during the molecular distillation process is recovered after secondary condensation and cold trap condensation.

5. The tire pyrolysis oil fractionation separation method according to claim 1, characterized in that: The refrigerant used in the cold trap is a mixture of anhydrous ethanol and dry ice.

6. The tire pyrolysis oil fractionation separation method according to claim 1, characterized in that: In the above 2), the condensing medium used in the molecular distillation process is a mixture of ethylene glycol and water.

7. The tire pyrolysis oil fractionation separation method according to claim 6, characterized in that: The volume ratio of the ethylene glycol to water is (50-60): (50-40).

8. The tire pyrolysis oil fractionation separation method according to claim 1, characterized in that: After the molecular distillation process is completed, a diluent is used to clean the inner wall of the molecular distiller to ensure that each fraction of oil is completely collected.

9. The tire pyrolysis oil fractionation separation method according to claim 1, characterized in that: In the above 3), a rotary evaporator is used to completely evaporate the dichloromethane in each fraction oil.

10. The tire pyrolysis oil fractionation separation method according to claim 1, characterized in that: The tire pyrolysis oil in 1) is the full-component pyrolysis oil of waste tires at 400°C.

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