Solvent process for reducing total chlorine content of tire oil

Abstract

The present application relates to the tire oil refining technical field, disclose a kind of solvent method process for reducing the total chlorine content of tire oil, the process includes: tire pyrolysis oil is contacted with pre-reduction solvent and is reacted and is layered to obtain pre-reduction tire oil;It is continuously pumped from the bottom of self-extraction tower, and first, second functional solvents pumped from middle lower part, upper part respectively are carried out countercurrent extraction;After the light phase mixed solution is separated out polar solvent, it is mixed with iodine trapping liquid and is washed and layered to obtain oil phase after trapping and washing;Heavy phase salt-containing solvent part is main circulating flow, part is in the side line cooling and inorganic salt is precipitated, and then it is merged into the main circulating flow;Oil phase after trapping and washing is sequentially washed by sodium hydroxide solution and deionized water, and is layered to obtain low-chlorine refined tire oil.The present application is combined by countercurrent extraction and side line salt discharge, which helps to improve the impurity removal effect, and reduces the solvent loss and residual impurities in finished oil.

Description

Technical Field

[0001] This invention relates to the field of tire oil refining technology, specifically a solvent-based process for reducing the total chlorine content of tire oil. Background Technology

[0002] Pyrolysis of waste tires is an important method for the resource utilization of rubber. The tire oil obtained from pyrolysis can be used as fuel oil or further processed into light oil products or chemical raw materials. During pyrolysis, some chlorine-containing rubbers, chlorine-containing additives, or other chlorine-containing components in tire formulations can form organochlorine compounds that enter the oil phase. These chlorine-containing substances are prone to generating corrosive chlorine-containing substances during subsequent heating, catalytic processing, or storage and transportation, causing a decrease in catalyst activity, equipment corrosion, and fluctuations in product quality, thus affecting the subsequent processing and utilization of the tire oil.

[0003] To meet the requirements of industrial processing for low-chlorinated oils, tire oils need to undergo dechlorination treatment. Among non-hydrodechlorination processes, the solvent method is valuable due to its relatively mild reaction conditions and strong equipment adaptability. This method typically uses a polar solvent as the reaction and phase separation medium, causing chlorinated compounds in the oil phase to transfer or transform during the contact between the polar solvent and the non-polar oil phase, carrying the chlorinated components into the polar solvent phase, thereby reducing the total chlorine content in the oil.

[0004] Existing solvent-based methods for the continuous treatment of chlorinated tire oil still have shortcomings. On the one hand, the raw oil contains oxidizing components such as peroxides, which consume reducing or nucleophilic components in the solvent, affecting the efficiency of subsequent dechlorination reactions. Simultaneously, some processes pre-mix and add multiple active agents, making it difficult to maintain stable interphase contact and mass transfer conditions during the reaction. Some active components may also be entrained in the oil phase, increasing residual impurities in the finished oil. On the other hand, inorganic salts generated during continuous operation gradually enter the polar solvent phase. Accumulated salts can easily precipitate and cause blockages in pipelines or equipment. If the circulating solvent is subjected to full-volume cooling and desalting, it will increase the loss of polar solvents during filter cake and transfer processes, weaken the promoting effect of appropriate salt concentration on oil-water separation, and prolong the subsequent phase separation time.

[0005] Therefore, this invention proposes a solvent-based process to reduce the total chlorine content of tire oil, thereby addressing the shortcomings of existing technologies. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a solvent-based process for reducing the total chlorine content of tire oil. This process solves the problems of conventional treatment processes, which are unable to effectively reduce halogen impurities in waste rubber pyrolysis products and are prone to solvent loss and crystallization blockage during the treatment process.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A solvent-based process for reducing the total chlorine content of tire oil includes the following steps:

[0009] S1. Tire pyrolysis oil is mixed with pre-reducing solvent and subjected to a contact reaction. After the reaction, the mixture is allowed to stand and separate into layers to obtain the upper layer of pre-reduced tire oil. S2. The pre-reduced tire oil is subjected to a countercurrent extraction reaction with a first functional solvent and a second functional solvent in a continuous countercurrent rotary extractor. After the reaction, a light phase mixture overflowing from the top of the continuous countercurrent rotary extractor and a heavy phase salt-containing solvent flowing from the bottom are obtained. The pre-reduced tire oil is continuously pumped into the continuous countercurrent rotary extractor from the bottom, the first functional solvent from the lower middle section, and the second functional solvent from the top. S3. The light phase mixture is kept at a constant temperature and allowed to stand. The mixture is allowed to separate into layers, and the polar solvent is separated to obtain a crude dechlorinated oil phase. The crude dechlorinated oil phase is then mixed with an iodine-collecting solution for washing, and allowed to stand for layer separation to obtain the lower iodine-containing waste liquid, resulting in the upper oil phase after collection and washing. S4: The heavy phase containing salt is divided into two parts by weight. The first part is used as the main circulating stream, and the second part is introduced into the crystallization equipment as a side-stream salt discharge stream. The inorganic salt solids are precipitated by cooling and then filtered. The resulting low-salt clear liquid is then incorporated into the main circulating stream. S5: The oil phase after collection and washing is mixed with a sodium hydroxide solution for washing, and allowed to stand for layer separation to obtain an alkaline-washed oil phase. The alkaline-washed oil phase is then mixed with deionized water for washing, and allowed to stand for layer separation to obtain low-chlorinated refined tire oil.

[0010] This process combines pre-reduction treatment, multi-stage countercurrent solvent extraction, iodine capture washing, and side-stream salt control circulation, which helps promote the transfer or conversion of chlorine-containing compounds, reduce the peroxide value of oils, and decrease the amount of base solvent to be replenished. Its relevant operational processes are as follows:

[0011] In step S1, the tire pyrolysis oil is pre-mixed with a pre-reducing solvent containing reducing substances. This stage allows the highly oxidizing peroxide components in the oil phase to be converted and consumed, resulting in a decrease in the overall peroxide value of the oil. This operation reduces the consumption of reducing and nucleophilic materials in the subsequent main dechlorination process by oxidizing substances, which is beneficial to the subsequent dechlorination reaction.

[0012] In step S2, the physical structure of the continuous countercurrent rotary extractor enhances the coordination of mass transfer and reaction. The oil phase fluid moves from bottom to top, contacting the polar fluid moving from top to bottom in a countercurrent manner. The first functional solvent containing the phase transfer component and the second functional solvent containing the nucleophilic component are pumped in in stages, forming relatively partitioned contacts within the column. In this process, the oil phase first contacts the first functional solvent pumped in from the middle and lower part, and then contacts the second functional solvent pumped in from the upper part. The first functional solvent helps promote the transfer of organochlorine in the oil phase to the polar interface, while the second functional solvent helps to promote at least some of the organochlorine to undergo nucleophilic substitution reactions and accumulate as inorganic salts in the settling heavy phase solvent. The staged feeding method can mitigate the problem of decreased mass transfer driving force caused by pre-mixing of active agents.

[0013] In step S3, to address the issue of residual impurities in the separated dechlorinated oil phase, an iodine-containing thiosulfate-collecting solution is introduced for washing. Thiosulfate ions can react with free or weakly bound iodine-containing substances to form iodide salts that are easily soluble in the aqueous phase and are discharged with the bottom waste liquid. This operation helps reduce residual iodine in the oil caused by the upstream phase transfer reaction.

[0014] In step S4, the fluid circulation involves a non-full-volume treatment process involving side-stream salt removal. Only a fixed proportion of the heavy phase fluid is extracted for cooling, precipitation, and filtration, while the remaining bulk fluid directly enters the circulation. This operation helps control the unidirectional increase in inorganic salt concentration in the fluid and reduces the risk of pipeline crystallization and blockage. Simultaneously, the appropriate amount of inorganic salt retained in the main circulating fluid maintains a certain degree of salting-out effect in the circulating flow. A certain concentration of salt can increase the density difference and interfacial tension between the polar and non-polar phases, which is beneficial for the demulsification and sedimentation separation process of the oil-water two phases. Furthermore, the incomplete filtration process reduces the entrainment loss of the basic polar solvent in the filter cake.

[0015] In step S5, the collected and washed oil phase is subjected to alkali washing and water washing in sequence. Sodium hydroxide solution can neutralize or convert residual acidic components or saponifiable impurities in the oil phase, and helps reduce some of the polar impurities remaining from the aforementioned treatment. Subsequent washing with deionized water further removes residual inorganic salts, alkaline components, and water-soluble impurities from the oil phase. This combined alkali washing and water washing treatment helps reduce the residual impurity content in the refined oil and obtains low-chlorine refined tire oil.

[0016] Preferably, in step S1, the weight ratio of tire pyrolysis oil to pre-reduction solvent is 100:15-25; the contact reaction temperature is 60-110℃, and the contact reaction time is 5-40 min. In step S2, the overall operating temperature of the continuous countercurrent rotary extractor is controlled at 120-160℃, the operating pressure is controlled at 1.5-2.5 MPa, and the total contact residence time of the pre-reduced tire oil is 1.0-4.0 h; for every 100 parts by weight of tire pyrolysis oil processed, the pumping rate of the first functional solvent is 40-60 parts by weight, and the pumping rate of the second functional solvent is 40-60 parts by weight. In step S3, the light phase mixture is kept at 60-90℃ for 45-75 min; based on 100 parts by weight of tire pyrolysis oil processed, the amount of iodine trapping solution added is 10-20 parts by weight, the mixing and washing temperature is 50-80℃, and the mixing and washing time is 10-30 min. In step S4, the second part, acting as a side-stream salt discharge stream, accounts for 10%-20% of the total weight of the heavy phase salt-containing solvent, and the target temperature for precipitation is 20-40℃. After the resulting low-salt clarified liquid is incorporated into the main circulation stream, the total mass concentration of dissolved inorganic salts in the main circulation stream is controlled within the range of 0.8%-3.2%. In step S5, the mass concentration of sodium hydroxide solution is 3%-8%. Based on 100 parts by weight of tire pyrolysis oil processed, the amount of sodium hydroxide solution added is 10-20 parts by weight, and the amount of deionized water added is 8-15 parts by weight. The washing temperature with sodium hydroxide solution is 70-85℃, and the time is 15-25 min. The washing temperature with deionized water is 60-75℃, and the time is 10-20 min.

[0017] The above parameters define the operating range of each step. The temperature and time conditions in step S1 are conducive to the pre-reduction treatment and can reduce excessive cracking of oil components. The operating temperature and pressure in step S2 help maintain the polar solvent in a liquid state and provide reaction conditions for the nucleophilic substitution reaction. The settling temperature, settling time, and amount of iodine trapping solution added in step S3 help the light phase mixture to separate into layers and the washing and transfer of iodine-containing substances. Step S4 combines a specific salt removal ratio and an inorganic salt mass concentration range to achieve a balance between controlling crystal accumulation and maintaining the salting-out demulsification effect. The alkaline washing and water washing temperature and time in step S5 help remove residual acidic components, alkaline components, and water-soluble impurities in the oil phase.

[0018] Preferably, the pre-reduction solvent is made from raw materials containing ethylene glycol, deionized water, and anhydrous sodium sulfite; the iodine capturing solution is made from raw materials containing ethylene glycol, deionized water, and sodium thiosulfate; the first functional solvent is made from raw materials containing ethylene glycol, polyethylene glycol 400, and potassium iodide; the second functional solvent is made from raw materials containing ethylene glycol, deionized water, anhydrous sodium sulfite, and sodium hydrosulfide; in step S4, the obtained main circulating flow is pumped back to the solution preparation section, and the total mass concentration of dissolved inorganic salts in the circulating base solution is monitored in real time by an online detection and analysis instrument; the main circulating flow is used to replace at least part of the fresh base solvent required for preparing the first functional solvent and / or the second functional solvent, and after replenishing the active agent consumed in the reaction to complete the solvent compounding and regeneration, it re-enters step S2 for recycling.

[0019] The solvent composition, preparation process, and circulation method described above clearly define the main reaction media and regeneration pathways in each step. Ethylene glycol and polyethylene glycol serve as polar media for phase separation and mass transfer; potassium iodide acts as a phase transfer component; and anhydrous sodium sulfite and sodium hydrosulfide provide reducing and nucleophilic active substances. The main circulating pump, with controlled salt concentration, returns to the solution preparation section to replace the fresh polar solvent, completing the compounding and regeneration process by replenishing the active solid reagents consumed in the chemical reaction. This method helps to reduce the amount of base solvent replenished while maintaining extraction, separation, and conversion.

[0020] This invention provides a solvent-based process for reducing the total chlorine content of tire oil, which has the following beneficial effects:

[0021] 1. This invention introduces a combination of pre-reduction and countercurrent extraction into the process of reducing impurities in tire oil. This pretreatment preferentially converts highly oxidizing substances, reducing reagent consumption in subsequent stages. Combined with the segmented feeding method used in solvent extraction, partitioned contact is formed within the extraction equipment, allowing phase transfer and nucleophilic substitution reactions to occur in corresponding regions. This process helps maintain the driving force for interphase mass transfer, thereby reducing the total chlorine content of the product.

[0022] 2. This invention reduces iodine residue generated during impurity removal by introducing an iodine-collecting solution containing thiosulfate into the light phase treatment section for mixed washing. This operation converts iodine-containing substances remaining in the crude dechlorinated oil phase after phase transfer reaction into iodide salts that are easily soluble in the aqueous phase and then separates and discharges them. This reduces the total chlorine content of tire oil while also helping to reduce iodine residue in the finished oil product.

[0023] 3. This invention employs a side-stream salt-discharge circulation distribution method for the heavy-phase salt-containing solvent, extracting only a portion of the fluid for precipitation and filtration desalination during continuous operation. This operation helps control crystallization blockage caused by the continuous increase in inorganic salt concentration; simultaneously, the inorganic salts retained in the main circulation stream maintain the salting-out effect in the solvent-based treatment process, which is beneficial for oil-water demulsification. This method reduces the total chlorine content in tire oil while minimizing the entrainment loss of the basic polar solvent. Attached Figure Description

[0024] Figure 1 This is a flow chart of the solvent method process for reducing the total chlorine content of tire oil according to the present invention. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The sources and specifications of the main raw materials and reagents used in the following examples and comparative examples are as follows. Reagents not specifically mentioned may be commercially available analytical grade or higher grade products.

[0027] Tire pyrolysis oil is derived from the pyrolysis process of waste tires. Testing revealed that the main physical property of the raw material is a density of 0.94 g / cm³. 3 (20℃), moisture 0.3wt%, initial total chlorine content 412μg / g, peroxide value 2.5mmol / kg.

[0028] Polyethylene glycol 400, with CAS number 25322-68-3, is a non-ionic, water-soluble homopolymer formed by the condensation polymerization of ethylene oxide and water. Its main repeating unit is oxyethylene, and its average molecular weight is between 380 and 420.

[0029] Ethylene glycol, potassium iodide, sodium hydrosulfide, sodium sulfite, sodium thiosulfate, sodium hydroxide, and deionized water can all be conventional chemical reagents in this field, and commercially available industrial-grade or analytical-grade products can be used. Specifically, the mass fraction of the liquid ethylene glycol used is ≥99.5%; the potassium iodide, anhydrous sodium sulfite, sodium thiosulfate, and sodium hydroxide used are all analytical-grade solids with a mass fraction ≥99.0%; and the sodium hydrosulfide used is an industrial-grade solid with a mass fraction ≥70% (in each preparation example, these are all calculated as pure effective mass).

[0030] Preparation Example 1:

[0031] This preparation example provides a method for preparing a first functional solvent, comprising the following steps:

[0032] Step 1: 85.5 parts by weight of ethylene glycol and 14 parts by weight of polyethylene glycol 400 are loaded into a reactor equipped with a stirring device and mixed at 60°C and a stirring speed of 300 r / min for 15 min to obtain a clear alcohol-ether mixture.

[0033] Step 2: Add 0.5 parts by weight of potassium iodide powder to the alcohol-ether mixture obtained in Step 1, raise the temperature of the reactor to 70°C, and stir continuously at a stirring speed of 400 r / min for 30 min until no obvious solid particles are observed to obtain the first functional solvent.

[0034] Preparation Example 2:

[0035] This preparation example provides a method for preparing a first functional solvent, comprising the following steps:

[0036] Step 1: 82.5 parts by weight of ethylene glycol and 16.5 parts by weight of polyethylene glycol 400 are loaded into a reactor equipped with a stirring device and mixed at 65°C and a stirring speed of 350 r / min for 20 min to obtain a clear alcohol-ether mixture.

[0037] Step 2: Add 1.0 part by weight of potassium iodide powder to the alcohol-ether mixture obtained in Step 1, raise the temperature of the reactor to 75°C, and stir continuously at a stirring speed of 450 r / min for 40 min until no obvious solid particles are observed, thus obtaining the first functional solvent.

[0038] Preparation Example 3:

[0039] This preparation example provides a method for preparing a first functional solvent, comprising the following steps:

[0040] Step 1: 79.5 parts by weight of ethylene glycol and 19 parts by weight of polyethylene glycol 400 are loaded into a reactor equipped with a stirring device and mixed at 70°C and a stirring speed of 400 r / min for 25 min to obtain a clear alcohol-ether mixture.

[0041] Step 2: Add 1.5 parts by weight of potassium iodide powder to the alcohol-ether mixture obtained in Step 1, maintain the temperature of the reactor at 80°C, and stir continuously at a stirring speed of 500 r / min for 50 min until no obvious solid particles are observed, thus obtaining the first functional solvent.

[0042] Preparation Example 4:

[0043] This preparation example provides a method for preparing a second functional solvent, comprising the following steps:

[0044] Step 1: Add 87.7 parts by weight of ethylene glycol and 10 parts by weight of deionized water to a mixing tank, and mix at 50°C and a stirring speed of 200 r / min for 10 min to obtain an initial alcohol-water mixture.

[0045] Step 2: Add 0.3 parts by weight of anhydrous sodium sulfite to the initial alcohol-water mixture obtained in Step 1, and mix at 60°C and a stirring speed of 300 r / min for 20 min until the solid is completely dissolved to obtain an alcohol-water solution containing the reducing agent.

[0046] Step 3: Add 2.0 parts by weight of sodium hydrosulfide to the alcohol-water solution containing reducing agent obtained in Step 2, and mix continuously at 70°C and a stirring speed of 400 r / min for 45 min to obtain the second functional solvent.

[0047] Preparation Example 5:

[0048] This preparation example provides a method for preparing a second functional solvent, comprising the following steps:

[0049] Step 1: Add 83.4 parts by weight of ethylene glycol and 12.5 parts by weight of deionized water to a mixing tank and mix at 55°C and a stirring speed of 250 r / min for 15 min to obtain an initial alcohol-water mixture.

[0050] Step 2: Add 0.8 parts by weight of anhydrous sodium sulfite to the initial alcohol-water mixture obtained in Step 1, and mix at 350 r / min at 65°C for 30 min until the solid is completely dissolved to obtain an alcohol-water solution containing the reducing agent.

[0051] Step 3: Add 3.3 parts by weight of sodium hydrosulfide to the alcohol-water solution containing reducing agent obtained in Step 2, and mix continuously at 75°C and a stirring speed of 450 r / min for 50 min to obtain the second functional solvent.

[0052] Preparation Example 6:

[0053] This preparation example provides a method for preparing a second functional solvent, comprising the following steps:

[0054] Step 1: Add 79.8 parts by weight of ethylene glycol and 15 parts by weight of deionized water to a mixing tank, and mix at 60°C and a stirring speed of 300 r / min for 20 min to obtain an initial alcohol-water mixture.

[0055] Step 2: Add 1.2 parts by weight of anhydrous sodium sulfite to the initial alcohol-water mixture obtained in Step 1, and mix at 70°C and a stirring speed of 400 r / min for 40 min until the solid is completely dissolved to obtain an alcohol-water solution containing the reducing agent.

[0056] Step 3: Add 4.0 parts by weight of sodium hydrosulfide to the alcohol-water solution containing reducing agent obtained in Step 2, and mix continuously at 80°C and a stirring speed of 500 r / min for 60 min to obtain the second functional solvent.

[0057] Preparation Example 7:

[0058] This preparation example provides a method for preparing a pre-reducing solvent, including the following steps:

[0059] Step 1: Put 88 parts by weight of ethylene glycol and 10 parts by weight of deionized water into a mixing tank and mix at 50°C and a stirring speed of 300 r / min for 15 min to obtain the bottom dispersion.

[0060] Step 2: Add 2 parts by weight of anhydrous sodium sulfite powder to the bottom dispersion obtained in Step 1, and mix at 60°C and a stirring speed of 400 r / min for 40 min until the solid particles disappear to obtain the pre-reducing solvent.

[0061] Preparation Example 8:

[0062] This preparation example provides a method for preparing an iodine capturing solution, including the following steps:

[0063] Step 1: Add 75 parts by weight of ethylene glycol and 20 parts by weight of deionized water into a mixing vessel, and mix at 40°C and a stirring speed of 200 r / min for 10 min to obtain the aqueous alcohol base solution.

[0064] Step 2: Add 5 parts by weight of sodium thiosulfate to the aqueous alcohol base solution obtained in Step 1, and mix at 350 r / min for 30 min at 50°C to obtain the iodine collection solution.

[0065] The following examples provide a solvent-based process for reducing the total chlorine content of tire oil, combined with... Figure 1 As shown, the process includes the following steps: S1, pre-reduction treatment; S2, countercurrent absorption and conversion; S3, light phase washing and iodine capture; S4, heavy phase side-stream salt discharge; S5, post-treatment purification.

[0066] Example 1:

[0067] This embodiment provides a solvent-based process for reducing the total chlorine content of tire oil, including the following steps:

[0068] S1. 100 parts by weight of tire pyrolysis oil and 20 parts by weight of the pre-reduced solvent obtained in Preparation Example 7 are continuously pumped into a stirred reactor equipped with baffles and reacted at 85°C and a rotation speed of 300 r / min for 20 min to obtain a pre-reduced mixture. The pre-reduced mixture is transferred to a settling tank and settling at 85°C for 30 min to separate the layers, and the lower waste liquid is separated to obtain the upper pre-reduced tire oil.

[0069] S2. The pre-reduced tire oil obtained in S1 is continuously pumped into the bottom of the continuous countercurrent rotary extractor; 50 parts by weight of the first functional solvent obtained in Preparation Example 2 is continuously pumped into the middle and lower part of the extractor; 50 parts by weight of the second functional solvent obtained in Preparation Example 5 is continuously pumped into the top of the extractor; the overall operating temperature of the extractor is controlled at 130°C, the operating pressure is controlled at 2.0 MPa by the back pressure valve, and the total contact residence time of the pre-reduced tire oil in the extractor is controlled at 2.0 h; after the reaction is completed, a light phase mixture overflowing from the top of the tower and a heavy phase salt-containing solvent flowing out from the bottom of the tower are obtained.

[0070] S3. The light phase mixture obtained in S2 is introduced into a light phase clarification tank and kept at 75°C for 60 min to obtain a layered liquid with a distinguishable oil-water interface; the bottom polar solvent is separated to obtain a crude dechlorinated oil phase; the crude dechlorinated oil phase and 15 parts by weight of the iodine capturing solution obtained in Preparation Example 8 are added to a washing tank and washed at 65°C and a speed of 250 r / min for 20 min; after standing and separating, the lower layer of iodine-containing waste liquid is separated to obtain the captured and washed oil phase.

[0071] S4. The heavy phase salt-containing solvent obtained in S2 is divided into two parts by weight. 85% of the weight portion is directly returned to the solution preparation section for recycling as the main circulation stream. The remaining 15% of the weight portion is introduced into the cooling crystallizer as a side-stream salt discharge stream. The temperature is lowered to 30°C under stirring, and the mixture is kept at this temperature for 2.0 hours to settle. The precipitated inorganic salt solids are separated by a plate and frame filter to obtain a low-salt clear liquid. The low-salt clear liquid is then incorporated into the main circulation stream. Through this operation, the total mass concentration of dissolved inorganic salts in the main circulation stream is controlled within the range of 1.8% to 2.2%.

[0072] S5. The collected and washed oil phase obtained in S3 is mixed with 15 parts by weight of a 5% sodium hydroxide solution and washed at 80°C and 300 r / min for 20 min. After standing and separating, the alkaline-washed oil phase is obtained. The alkaline-washed oil phase is mixed with 10 parts by weight of deionized water and washed at 70°C and 300 r / min for 15 min. After standing and separating, the low-chlorine refined tire oil is obtained.

[0073] Example 2:

[0074] This embodiment provides a solvent-based process for reducing the total chlorine content of tire oil, including the following steps:

[0075] S1. 100 parts by weight of tire pyrolysis oil and 15 parts by weight of the pre-reduced solvent obtained in Preparation Example 7 are continuously pumped into a stirred reactor equipped with baffles and reacted at 60°C and a rotation speed of 250 r / min for 5 min to obtain a pre-reduced mixture. The pre-reduced mixture is transferred to a settling tank and settling at 60°C for 20 min to separate the layers. The lower waste liquid is separated to obtain the upper pre-reduced tire oil.

[0076] S2. The pre-reduced tire oil obtained in S1 is continuously pumped into the bottom of the continuous countercurrent rotary extractor; 40 parts by weight of the first functional solvent obtained in Preparation Example 1 is continuously pumped into the middle and lower part of the extractor; 40 parts by weight of the second functional solvent obtained in Preparation Example 4 is continuously pumped into the top of the extractor; the overall operating temperature of the extractor is controlled at 120°C, the operating pressure is controlled at 1.5 MPa by the back pressure valve, and the total contact residence time of the pre-reduced tire oil in the extractor is controlled at 1.0 h; after the reaction is completed, a light phase mixture overflowing from the top of the tower and a heavy phase salt-containing solvent flowing out from the bottom of the tower are obtained.

[0077] S3. The light phase mixture obtained in S2 is introduced into a light phase clarification tank and kept at 60°C for 45 min to obtain a layered liquid with a distinguishable oil-water interface; the bottom polar solvent is separated to obtain a crude dechlorinated oil phase; the crude dechlorinated oil phase and 10 parts by weight of the iodine capturing solution obtained in Preparation Example 8 are added to a washing tank and washed at 50°C and a speed of 200 r / min for 10 min; after standing and separating, the lower layer of iodine-containing waste liquid is separated to obtain the captured and washed oil phase.

[0078] S4. The heavy phase salt-containing solvent obtained in S2 is divided into two parts by weight. 90% of the weight portion is directly returned to the solution preparation section for recycling as the main circulation stream. The remaining 10% of the weight portion is introduced into the cooling crystallizer as a side-stream salt discharge stream. The temperature is lowered to 20°C under stirring, and the mixture is kept at this temperature for 1.0 h to settle. The precipitated inorganic salt solids are separated by a plate and frame filter to obtain a low-salt clear liquid. The low-salt clear liquid is then incorporated into the main circulation stream. Through this operation, the total mass concentration of dissolved inorganic salts in the main circulation stream is controlled within the range of 0.8% to 1.2%.

[0079] S5. The collected and washed oil phase obtained in S3 is mixed with 10 parts by weight of a 3% sodium hydroxide solution and washed at 70°C and 250 r / min for 15 min. After standing and separating, the alkaline washed oil phase is obtained. The alkaline washed oil phase is mixed with 8 parts by weight of deionized water and washed at 60°C and 250 r / min for 10 min. After standing and separating, the low-chlorine refined tire oil is obtained.

[0080] Example 3:

[0081] This embodiment provides a solvent-based process for reducing the total chlorine content of tire oil, including the following steps:

[0082] S1. 100 parts by weight of tire pyrolysis oil and 25 parts by weight of the pre-reduced solvent obtained in Preparation Example 7 are continuously pumped into a stirred reactor equipped with baffles and reacted at 110°C and a rotation speed of 350 r / min for 40 min to obtain a pre-reduced mixture. The pre-reduced mixture is transferred to a settling tank and settling at 110°C for 40 min to separate the layers, and the lower waste liquid is separated to obtain the upper pre-reduced tire oil.

[0083] S2. The pre-reduced tire oil obtained in S1 is continuously pumped into the bottom of the continuous countercurrent rotary extractor; 60 parts by weight of the first functional solvent obtained in Preparation Example 3 is continuously pumped into the middle and lower part of the extractor; 60 parts by weight of the second functional solvent obtained in Preparation Example 6 is continuously pumped into the top of the extractor; the overall operating temperature of the extractor is controlled at 160°C, the operating pressure is controlled at 2.5 MPa by the back pressure valve, and the total contact residence time of the pre-reduced tire oil in the extractor is controlled at 4.0 h; after the reaction is completed, a light phase mixture overflowing from the top of the tower and a heavy phase salt-containing solvent flowing out from the bottom of the tower are obtained.

[0084] S3. The light phase mixture obtained in S2 is introduced into a light phase clarification tank and kept at 90°C for 75 min to obtain a layered liquid with a distinguishable oil-water interface; the bottom polar solvent is separated to obtain a crude dechlorinated oil phase; the crude dechlorinated oil phase and 20 parts by weight of the iodine capturing solution obtained in Preparation Example 8 are added to a washing tank and washed at 80°C and a speed of 300 r / min for 30 min; after standing and separating, the lower layer of iodine-containing waste liquid is separated to obtain the captured and washed oil phase.

[0085] S4. The heavy phase salt-containing solvent obtained in S2 is divided into two parts by weight. 80% of the weight portion is directly returned to the solution preparation section for recycling as the main circulation stream. The remaining 20% ​​of the weight portion is introduced into the cooling crystallizer as a side-stream salt discharge stream. The temperature is lowered to 40°C under stirring, and the mixture is kept at this temperature for 3.0 hours to settle. The precipitated inorganic salt solids are separated by a plate and frame filter to obtain a low-salt clear liquid. The low-salt clear liquid is then incorporated into the main circulation stream. Through this operation, the total mass concentration of dissolved inorganic salts in the main circulation stream is controlled within the range of 2.8% to 3.2%.

[0086] S5. The collected and washed oil phase obtained in S3 is mixed with 20 parts by weight of a sodium hydroxide solution with a mass concentration of 8%, and washed at 85°C and 350 r / min for 25 min. After standing and separating, the alkaline washed oil phase is obtained. The alkaline washed oil phase is mixed with 15 parts by weight of deionized water, and washed at 75°C and 350 r / min for 20 min. After standing and separating, the low-chlorine refined tire oil is obtained.

[0087] In step S2 of the above embodiment, at least some of the organic chlorine in the tire pyrolysis oil can be converted into inorganic salts and enriched in the heavy phase solvent. If the heavy phase solvent is circulated in its entirety without desalination, inorganic salts may gradually accumulate in the circulating fluid, thereby increasing the risk of crystallization blockage in equipment and pipelines, and potentially altering the phase equilibrium of the fluid, thus exacerbating emulsification. Through the side-stream salt discharge operation in S4, a portion of the heavy phase fluid is extracted proportionally for cooling and crystallization to remove the enriched inorganic salts. The resulting low-salt clear liquid is then merged with the main circulating flow. This operation helps maintain the inorganic salt concentration in the circulating loop within a specific range (e.g., controlled between 0.8% and 3.2%). Maintaining the inorganic salt concentration within this range helps reduce the risk of blockage caused by excessive accumulation of inorganic salts. Furthermore, the salting-out effect can be utilized to increase the density difference and interfacial tension between the polar solvent phase and the non-polar oil phase, thereby promoting demulsification in step S3 and reducing the time required for settling and stratification. The main circulating stream after step S4 is pumped back to the solution preparation section. Specifically, this main circulating stream contains polar solvent components such as ethylene glycol, polyethylene glycol 400, and deionized water. In the solution preparation section, it can be used to replace at least part of the fresh base solvent required to prepare the first and second functional solvents in the above preparation example, based on the composition detection results. After quantitatively replenishing the active agents such as potassium iodide, sodium hydrosulfide, and anhydrous sodium sulfite consumed in the reaction based on the detection results, the compounded solvent can be reused as the first and / or second functional solvents in step S2, thereby facilitating solvent recycling.

[0088] As a preferred industrial continuous operation implementation method, taking the specific process conditions of Example 1 as an example, after the system reaches steady-state operation, the low-salt clear liquid separated by the plate and frame filter in step S4 is continuously introduced online into the heavy phase main circulation pipeline, which accounts for 85%, for merging. The mixed polar fluid formed after merging is pumped back to the solution preparation section as the overall circulating base liquid. In the solution preparation section, the total mass concentration of dissolved inorganic salts in the circulating base liquid is monitored in real time using an online detection and analysis instrument installed on the pipeline, and controlled within the salting-out range of 1.8% to 2.2%. Because the circulating base solution contains a certain amount of ethylene glycol and polyethylene glycol 400, the amount of fresh base solvent added can be reduced during solvent regeneration. Furthermore, based on the stoichiometric analysis of process consumption, when preparing the first functional solvent, potassium iodide solid particles reduced by the reaction can be quantitatively added to the circulating base solution; when preparing the second functional solvent, anhydrous sodium sulfite and sodium hydrosulfide solid particles consumed can be quantitatively added to the circulating base solution, and these particles are fully dissolved under stirring to complete the solvent compounding and regeneration. In the operational test of this embodiment, when the compounding method was continuously circulated for no less than 50 cycles, the salt load in the entire process loop could be maintained in a relatively balanced state. The clarification and demulsification rate in step S3 remained basically stable, no significant extension of the settling and stratification time was observed, and the total dechlorination efficiency of the discharged material could be maintained at a level similar to that of Example 1, which is beneficial for reducing the consumption of fresh base solvent.

[0089] Furthermore, the stirred reactor equipped with baffles, as well as the continuous countercurrent rotary extractor, light phase clarifying tank, cooling crystallizer, plate and frame filter, and other reaction and separation equipment mentioned in the embodiments of this invention, can all be commonly used reaction and separation equipment in the chemical industry. Specifically, the stirred reactor equipped with baffles used in step S1 has baffles inside that can interrupt the circumferential rotation of the fluid driven by the stirrer, thereby reducing or avoiding swirling phenomena and converting radial flow into axial tumbling. This helps to enhance the shear dispersion and mixing mass transfer effect between the non-polar tire oil and the polar pre-reduced solvent phases, and is beneficial to physical contact and chemical reaction. Those skilled in the art can configure and use the above-mentioned equipment by purchasing commercially available products or through conventional engineering design methods, depending on the specific process scale.

[0090] Comparative Example 1:

[0091] Compared with Example 1, the difference is that in step S2, the method of pumping the solvent is changed. Specifically, instead of pumping the first functional solvent and the second functional solvent in stages, 50 parts by weight of the first functional solvent obtained from Preparation Example 2 and 50 parts by weight of the second functional solvent obtained from Preparation Example 5 are mixed evenly in the mixing tank in advance, and then the mixed solvent is continuously pumped into the middle and lower part of the continuous countercurrent rotary extractor. The rest are the same.

[0092] Comparative Example 2:

[0093] Compared with Example 1, the difference is that step S1 (i.e., no pre-reduction treatment operation) is cancelled, and in step S2, 100 parts by weight of untreated raw tire pyrolysis oil is directly and continuously pumped into the bottom of the continuous countercurrent rotary extractor. All other aspects are the same.

[0094] Comparative Example 3:

[0095] Compared with Example 1, the difference is that in step S3, the type of washing and collecting solution was changed. Specifically, 15 parts by weight of the iodine collecting solution obtained in Preparation Example 8 used in the washing of the crude dechlorinated oil phase was replaced with 15 parts by weight of deionized water, and the rest were the same.

[0096] Comparative Example 4:

[0097] Compared with Example 1, the difference is that in step S4, the circulation split ratio of the heavy phase salt-containing solvent is changed. Specifically, the side stream split ratio is not performed (i.e., the split operation of 85% main circulation and 15% side stream salt discharge is cancelled). Instead, all the heavy phase salt-containing solvent obtained in step S2 is introduced into the cooling crystallizer as salt discharge for cooling crystallization and filtration desalination. The resulting clear liquid is then returned to the solution preparation section, so that the total mass concentration of dissolved inorganic salts in the main circulation stream is lower than the above-mentioned salting-out control range and tends to be at a lower level. All other aspects are the same.

[0098] Test Example 1:

[0099] Experimental steps:

[0100] Based on the solvent dechlorination process established in Example 1, after the feed in the continuous operation loop reaches a stable operating state, the 1st, 12th, 24th, 38th and 50th continuous operation cycles are selected as sampling nodes to quantitatively sample the corresponding fluids.

[0101] At each sampling point, 500 mL of heavy phase salt-containing solvent was sampled from the bottom heavy phase outlet of the continuous countercurrent rotary extractor in step S2; simultaneously, 500 mL of circulating base liquid was sampled downstream of the confluence point of the side-line salt discharge pipeline and the main circulation pipeline in step S4. Quantitative samples of the above-mentioned heavy phase salt-containing solvent and circulating base liquid were measured separately, and the residual mass of inorganic salts in the samples was determined using the ash content determination method (residue on ignition method). The total mass concentration of inorganic salts in the heavy phase salt-containing solvent and the total mass concentration of inorganic salts in the circulating base liquid were calculated based on the sample mass. At the same time, the halide ion content in the samples was determined by silver nitrate titration.

[0102] At the corresponding sampling point, 1000 mL of light phase mixture was obtained by online sampling at the connection line between the overflow port of the extraction column and the light phase clarification tank in step S3. This light phase mixture was then transferred to a graduated thermostatic jacketed glass separatory funnel, and the fluid temperature inside the separatory funnel was maintained at 75°C using a circulating water bath.

[0103] Start the timer and observe and record the sedimentation and stratification time required for the fluid in the separatory funnel to separate from the initial emulsified and turbid state to the formation of a visually distinguishable oil-water interface between the bottom polar solvent and the upper coarse dechlorinated oil phase. This is the settling and stratification time of the light phase mixture. Record the settling and stratification time of the light phase mixture in each cycle, and observe the retention of emulsion flocculent matter at the oil-water interface after stratification is completed.

[0104] The experimental results are shown in Table 1:

[0105] Table 1: Record of Salt Concentration and Sedimentation Time in Different Operating Cycles of the Continuous Circulation Loop

[0106] Operation cycle (week / time) Total mass concentration of inorganic salts in the heavy phase salt-containing solvent (%) Total mass concentration of inorganic salts in circulating base solution (%) Light phase mixture settling time (min) Cycle 1 2.08 1.82 58 12th cycle 2.25 1.97 56 24th cycle 2.41 2.08 59 38th cycle 2.36 1.94 57 50th cycle 2.52 2.15 58

[0107] Test conclusion:

[0108] According to the data in Table 1, in Example 1, during the observation span of 50 consecutive operating cycles, the inorganic salt concentration in the heavy phase saline solvent discharged in step S2 increased from 2.08%, and then fluctuated between 2.25% and 2.52%. After the 15% side-stream salt removal operation in step S4, the inorganic salt concentration in the re-merged circulating base liquid was between 1.82% and 2.15%. These test results indicate that the side-stream salt removal operation helps to regulate the inorganic salt content, controlling its concentration within the set salting-out range. No unidirectional increase in inorganic salt concentration with prolonged operating cycles was observed, which helps reduce the risk of inorganic salt precipitation and deposition inside pipelines and equipment.

[0109] Meanwhile, the settling time of the light phase mixture corresponding to step S3 fluctuated between 56 and 59 minutes. This settling time corresponds to the operating conditions of settling at 75°C for 60 minutes in Example 1. These results indicate that maintaining a specific concentration of inorganic salts in the circulation loop helps to achieve salting out, and inorganic salts within a certain concentration range help improve the separation of the oil phase and the polar phase, and are beneficial for promoting demulsification and agglomeration sedimentation processes. The above data show that this process has good desalination, impurity removal, and demulsification separation effects under continuous operation conditions.

[0110] Test Example 2:

[0111] Experimental steps:

[0112] 1000 mL of untreated raw tire pyrolysis oil, the low-chlorine refined tire oil finally prepared in Examples 1, 2 and 3, and the refined tire oil finally prepared in Comparative Examples 1 and 2 were obtained as test samples for this test.

[0113] 50 mL of each of the above test samples was measured, and the total chlorine content in each sample was determined using the microcoulometric method. Based on the initial total chlorine content detected in the original tire pyrolysis oil, the dechlorination rate of the corresponding oils in each example and comparative example was calculated to obtain the dechlorination rate of each test sample. The dechlorination rate was calculated using the formula: (Total chlorine content of the original tire pyrolysis oil - Total chlorine content of the corresponding oil) / Total chlorine content of the original tire pyrolysis oil × 100%.

[0114] Take 50g of each of the above test samples separately, and determine the peroxide value of each test sample by iodometric titration. Record the volume of titrant consumed for each sample, and calculate the corresponding peroxide value data. Obtain the peroxide value of each test sample, and use it to characterize the change of peroxide content in oil products.

[0115] The experimental results are shown in Table 2:

[0116] Table 2: Record of Dechlorination Effect and Peroxide Value Test Data under Different Process Conditions

[0117] Test object Total chlorine content (μg / g) Dechlorination rate (%) Peroxide value (mmol / kg) Untreated raw tire pyrolysis oil 412.0 - 2.50 Low-chlorine refined tire oil prepared in Example 1 14.6 96.46 0.36 Low-chlorine refined tire oil prepared in Example 2 42.1 89.78 0.58 Low-chlorine refined tire oil prepared in Example 3 8.4 97.96 0.22 Refined tire oil prepared in Comparative Example 1 68.3 83.42 0.41 Refined tire oil prepared in Comparative Example 2 53.7 86.97 1.94

[0118] Test conclusion:

[0119] According to the data in Table 2, the total chlorine content of the low-chlorine refined tire oils obtained in Examples 1 to 3 all decreased to varying degrees compared with the original tire pyrolysis oil, with dechlorination rates ranging from 89.78% to 97.96% and peroxide values ​​decreasing to the range of 0.22 mmol / kg to 0.58 mmol / kg. These results indicate that the multi-stage solvent process provided by this invention helps to reduce the peroxide value of the oil while simultaneously reducing the total chlorine content.

[0120] Comparing the data from Example 1 and Comparative Example 1, it can be seen that, under similar conditions of total solvent feed and operating parameters, Comparative Example 1, which pre-mixed the first functional solvent and the second functional solvent and then pumped them in at a single point, achieved a dechlorination rate of 83.42% and a higher total chlorine content than Example 1. This result indicates that using a segmented countercurrent pumping method in step S2 helps to ensure that different active components contact in separate zones within the extraction tower. Pre-mixing the first functional solvent containing potassium iodide and the second functional solvent containing sodium hydride is detrimental to maintaining the interphase mass transfer driving force, thus affecting the synergistic conversion effect of phase transfer catalysis and nucleophilic substitution reaction.

[0121] Comparing the data from Example 1 and Comparative Example 2, it can be seen that Comparative Example 2, which omits the pre-reduction treatment in step S1, has a peroxide value of 1.94 mmol / kg and a dechlorination rate reduced to 86.97%. This result indicates that the oxidizing components corresponding to the higher peroxide value in the untreated oil can increase the consumption of the reducing components in the second functional solvent in step S2, and adversely affect the control of the oil's peroxide value and the dechlorination process.

[0122] In summary, the test data shows that the combination of steps S1 and S2 has a good synergistic effect in reducing the total chlorine content and controlling the peroxide value.

[0123] Test Example 3:

[0124] Experimental steps:

[0125] 1000 mL of low-chlorine refined tire oil was obtained from Examples 1, 2, 3, and 3 after stable operation on a continuous operating loop, and 1000 mL of refined tire oil was obtained from Comparative Example 4. These were used as test samples for determining the total iodine residue in the finished oil. Simultaneously, the continuous operating loops of Examples 1, 2, 3, 3, and 4 were selected, and the amount of fresh polar solvent replenished in the corresponding solution preparation section was recorded within the operating cycle of processing the same batch size (based on 1 ton of tire pyrolysis oil).

[0126] Take 50 mL of each of the above-obtained test samples and perform trace element analysis on the oil samples obtained from each of the above processes using inductively coupled plasma mass spectrometry (ICP-MS) to determine the iodine concentration in the samples and obtain the total iodine residue in the finished oil.

[0127] In the liquid preparation section of Examples 1, 2, 3, Comparative Examples 3 and 4, the total volume of basic solvents, including ethylene glycol, polyethylene glycol 400 and deionized water, was added to the main circulation stream to maintain the material balance of the entire process loop within a single cycle (i.e., the cycle in which 1 ton of tire pyrolysis oil is processed) using a pipeline metering pump and a level gauge. This volume was then converted into the consumption value per ton of tire pyrolysis oil processed to obtain the amount of fresh polar solvent replenished per cycle.

[0128] The experimental results are shown in Table 3:

[0129] Table 3: Record of Test Data on Iodine Residue and Polar Solvent Replenishment in Finished Oil under Different Process Conditions

[0130] Test object Total iodine residue in refined oil products (mg / kg) Single-cycle fresh polar solvent replenishment (L / ton of oil) Example 1 3.4 28.7 Example 2 4.5 32.1 Example 3 2.9 34.2 Comparative Example 3 52.1 30.2 Comparative Example 4 3.6 106.3

[0131] Test conclusion:

[0132] According to the data in Table 3, the total iodine residue in the finished oils obtained in Examples 1 to 3 ranged from 2.9 mg / kg to 4.5 mg / kg, and the amount of fresh polar solvent replenished per cycle ranged from 28.7 L / ton of oil to 34.2 L / ton of oil.

[0133] Comparing the data from Example 1 and Comparative Example 3, it can be seen that after replacing the iodine-collecting solution containing sodium thiosulfate with deionized water in step S3, the total iodine residue in the finished oil of Comparative Example 3 increased to 52.1 mg / kg. This result indicates that after the reaction, some of the iodine-containing components introduced in step S2 remain or are entrained in the non-polar oil phase, and simple water washing has limited ability to remove the residual or entrained iodine substances in the oil phase. However, the sodium thiosulfate used in Example 1 can react with some iodine-containing substances to form iodine salts that are easily soluble in polar solvents, thereby helping to reduce the residual amount of iodine substances in the oil phase.

[0134] Comparing the data from Example 1 and Comparative Example 4, it can be seen that Comparative Example 4, which did not perform proportional side-stream diversion in step S4 but instead introduced the entire amount of heavy phase salt-containing solvent into the cooling crystallizer for salt removal, had a single-cycle fresh polar solvent replenishment amount of 106.3 L / ton of oil. This result indicates that the full-volume cooling crystallization and filtration desalination operation increased the entrainment loss of polar solvent in the precipitated filter cake and the material loss during the transfer process. Simultaneously, the full-volume salt removal resulted in a lower inorganic salt concentration in the main circulating stream, weakening the salting-out effect and making some polar solvent components more easily carried out with the oil phase, thereby increasing the basic solvent replenishment amount in the liquid preparation section. The above data results demonstrate that the selection of reagents in the washing and collection section and the proportional diversion and salt control operation for the heavy phase fluid in this invention have a good synergistic effect in terms of material retention and continuous operation economy.

[0135] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for reducing the total chlorine content of tire oil by a solvent process, characterized in that, Includes the following steps: S1. Mix tire pyrolysis oil with pre-reducing solvent and react them. After the reaction, let the mixture stand to separate the lower waste liquid and obtain the upper pre-reduced tire oil. S2. The pre-reduced tire oil is subjected to a countercurrent extraction reaction with the first functional solvent and the second functional solvent in a continuous countercurrent rotary extractor. After the reaction is completed, a light phase mixture overflowing from the top of the continuous countercurrent rotary extractor and a heavy phase salt-containing solvent flowing out from the bottom of the tower are obtained respectively. The pre-reduced tire oil is continuously pumped in from the bottom of the continuous countercurrent rotary extractor, the first functional solvent is continuously pumped in from the middle and lower part, and the second functional solvent is continuously pumped in from the top. S3. The light phase mixture is kept at a constant temperature and allowed to stand to separate into layers, and the polar solvent is separated to obtain a crude dechlorinated oil phase; then the crude dechlorinated oil phase is mixed with iodine collecting solution for washing, and allowed to stand to separate into layers to obtain the lower layer of iodine-containing waste liquid, and the upper layer of collected and washed oil phase is obtained. S4. The heavy phase salt-containing solvent is divided into two parts by weight. The first part is used as the main circulation stream and the second part is introduced into the crystallization equipment as a side-stream salt discharge stream. The inorganic salt solid is cooled and precipitated and separated by filtration. The resulting low-salt clear liquid is then incorporated into the main circulation stream. S5. The collected and washed oil phase is mixed with sodium hydroxide solution and washed, and allowed to stand to separate into layers to obtain an alkaline washed oil phase; the alkaline washed oil phase is mixed with deionized water and washed, and allowed to stand to separate into layers to obtain low-chlorine refined tire oil.

2. The process for reducing the total oil content of chlorines in tyres by the solvent method according to claim 1, characterized by the fact that, In step S1, the weight ratio of the tire pyrolysis oil to the pre-reduced solvent is 100:(15-25); the temperature of the contact reaction is 60-110℃, and the contact reaction time is 5-40 min.

3. The solvent method process for reducing the total chlorine content of tire oil according to claim 1, characterized in that, In step S2, the overall operating temperature of the continuous countercurrent rotary extractor is controlled at 120-160℃, the operating pressure is controlled at 1.5-2.5MPa, and the total contact residence time of the pre-reduced tire oil is 1.0-4.0h. In step S2, for every 100 parts by weight of the tire pyrolysis oil processed, the pumping amount of the first functional solvent is 40-60 parts by weight, and the pumping amount of the second functional solvent is 40-60 parts by weight.

4. The solvent method process for reducing the total chlorine content of tire oil according to claim 1, characterized in that, In step S3, the light phase mixture is kept at 60-90℃ and allowed to stand for 45-75 minutes; based on 100 parts by weight of the tire pyrolysis oil, the amount of iodine capturing solution added is 10-20 parts by weight, the temperature of the mixing and washing is 50-80℃, and the time of the mixing and washing is 10-30 minutes.

5. The solvent method process for reducing the total chlorine content of tire oil according to claim 1, characterized in that, In step S4, the weight of the second part as the side-stream salt discharge stream accounts for 10%-20% of the total weight of the heavy phase salt-containing solvent, and the target temperature for the cooling precipitation is 20-40℃. In step S4, after the obtained low-salt clear liquid is incorporated into the main circulation stream, the total mass concentration of dissolved inorganic salts in the main circulation stream is controlled within the range of 0.8%-3.2%.

6. The solvent method process for reducing the total chlorine content of tire oil according to claim 1, characterized in that, In step S5, the mass concentration of the sodium hydroxide solution is 3%-8%, and based on 100 parts by weight of the tire pyrolysis oil processed, the amount of sodium hydroxide solution added is 10-20 parts by weight, and the amount of deionized water added is 8-15 parts by weight. In step S5, the washing temperature with the sodium hydroxide solution is 70-85℃ and the time is 15-25 min; the washing temperature with the deionized water is 60-75℃ and the time is 10-20 min.

7. The solvent method process for reducing the total chlorine content of tire oil according to claim 1, characterized in that, In step S1, the pre-reduction solvent is made from raw materials comprising the following parts by weight: ethylene glycol: 88 parts, deionized water: 10 parts, and anhydrous sodium sulfite: 2 parts; In step S3, the iodine capturing solution is made from the following raw materials in parts by weight: ethylene glycol: 75 parts, deionized water: 20 parts, sodium thiosulfate: 5 parts.

8. The solvent method process for reducing the total chlorine content of tire oil according to claim 1, characterized in that, In step S2, the first functional solvent is made from raw materials comprising the following parts by weight: ethylene glycol: 79.5-85.5 parts, polyethylene glycol 400: 14-19 parts, potassium iodide: 0.5-1.5 parts; In step S2, the second functional solvent is made from raw materials comprising the following parts by weight: ethylene glycol: 79.8-87.7 parts, deionized water: 10-15 parts, anhydrous sodium sulfite: 0.3-1.2 parts, and sodium hydrosulfide: 2.0-4.0 parts.

9. The solvent method process for reducing the total chlorine content of tire oil according to claim 8, characterized in that, In step S2, the preparation process of the first functional solvent is as follows: the ethylene glycol and the polyethylene glycol 400 are mixed at 60-70°C to obtain a clear alcohol-ether mixture, and then the potassium iodide is added and the temperature is raised to 70-80°C and stirred continuously until there are no solid particles. In step S2, the preparation process of the second functional solvent is as follows: the ethylene glycol and the deionized water are mixed at 50-60°C to obtain an initial alcohol-water mixture, anhydrous sodium sulfite is added and the temperature is raised to 60-70°C and stirred until the solid dissolves, and then sodium hydrosulfide is added and the temperature is raised to 70-80°C and stirred continuously.

10. The solvent method process for reducing the total chlorine content of tire oil according to claim 1, characterized in that, In step S4, the obtained main circulating flow is pumped back to the solution preparation section, and the total mass concentration of dissolved inorganic salts in the circulating base solution is monitored in real time by an online detection and analysis instrument. The main circulating flow is used to replace at least part of the fresh base solvent required to prepare the first functional solvent and / or the second functional solvent. After the active agent consumed by the reaction is replenished and the solvent is regenerated, it is recycled in step S2.

Images