Process for preparing modified plant pitch from waste oil hydrolysis rectification residue

Abstract

This invention belongs to the field of asphalt material technology, specifically disclosing a process for preparing modified plant asphalt from waste oil hydrolysis and distillation residues. The process includes the following steps: the waste oil hydrolysis and distillation residues are sequentially dehydrated, impurity-removed, and detoxified; a composite modifier is prepared using a composite system of a bio-based modifier, an inorganic modifier, and a crosslinking agent; the pretreated residues are heated and a polymerization catalyst is added to obtain a prepolymerized product; the composite modifier and a compatibility accelerator are added to the prepolymerized product; a UV absorber is added; and the asphalt is homogenized by grinding in a colloid mill and then cooled and molded. This invention utilizes the above-mentioned process for preparing modified plant asphalt from waste oil hydrolysis and distillation residues. Through an integrated process of pretreatment, composite modification, synergistic stabilization, and UV protection, it achieves high-volume, harmless utilization of the residues, while significantly improving the comprehensive performance and service life of the plant asphalt. Furthermore, the process is simple, energy-efficient, and suitable for continuous industrial production.

Description

Technical Field

[0001] This invention relates to the fields of solid waste resource utilization and asphalt material technology, and in particular to a process for preparing modified plant asphalt from waste oil hydrolysis and distillation residue. Background Technology

[0002] Waste oils (including waste cooking oil and industrial waste oil) are processed through hydrolysis and distillation to recover fatty acids, glycerol, and other products, but a large amount of distillation residue is generated. This residue has a complex composition, rich in high-boiling-point oils, polymers, small amounts of heavy metals, and organic impurities. It is characterized by high viscosity, high toxicity, and high difficulty in treatment. Currently, it is mainly disposed of by incineration and landfill, which not only wastes resources but also causes serious pollution to the soil, water, and atmospheric environment. Its harmless and resource-based disposal has become an urgent problem to be solved in the industry.

[0003] Plant-based asphalt, a new type of environmentally friendly asphalt material, is made from plant-derived raw materials. It boasts advantages such as being renewable and environmentally friendly, and can replace traditional petroleum asphalt in road construction, waterproofing projects, and other fields, alleviating the pressure of petroleum resource shortages. Currently, plant-based asphalt is mainly prepared from native plant oils and plant straw through processes such as thermal cracking and catalytic polymerization. However, this method suffers from problems such as high raw material costs, complex preparation processes, and unstable product performance (e.g., easy softening at high temperatures, easy cracking at low temperatures, and poor aging resistance), limiting its large-scale application.

[0004] Currently, there are a few studies on the preparation of bio-asphalt using waste oils, but most of them directly use the waste oil itself without designing a specific process for the hazardous waste, waste oil hydrolysis and distillation residue. Furthermore, existing processes generally suffer from low residue utilization, poor modification effects, and product performance that fails to meet engineering requirements. Specifically: 1) Impurities in the residue are not effectively removed, resulting in asphalt with a strong odor, poor stability, and a tendency to separate and accelerate aging; 2) The problem of harmless treatment of trace heavy metals in the residue has not been solved, posing a risk of secondary pollution. At the same time, a balance between high residue content and high asphalt performance has not been achieved, weakening the economic and environmental advantages of the technology; 3) During the modification reaction, the modifier and residue have poor compatibility, easily leading to agglomeration and uneven dispersion, further affecting asphalt performance.

[0005] Therefore, developing a modified plant asphalt preparation process that enables efficient resource utilization of waste oil hydrolysis and distillation residues, is simple in process, has low energy consumption, produces high-performance products, and causes no secondary pollution, is of great practical significance and industrial application value. Summary of the Invention

[0006] The purpose of this invention is to provide a process for preparing modified plant asphalt from waste oil hydrolysis and distillation residue. Through an integrated process of pretreatment, composite modification, synergistic stabilization, and ultraviolet protection, several original technologies are introduced to achieve high-volume and harmless utilization of the residue. At the same time, the comprehensive performance and service life of plant asphalt are significantly improved. Moreover, the process is simple, energy-efficient, and can be continuously produced industrially, overcoming the shortcomings of existing technologies and highlighting creativity and significant progress.

[0007] To achieve the above objectives, this invention provides a process for preparing modified plant bitumen from waste oil hydrolysis and distillation residue, comprising the following steps: Step 1: Pretreatment of waste oil hydrolysis distillation residue: Select waste oil hydrolysis distillation residue with water content ≤15%, acid value 80-120mgKOH / g, and viscosity 1200-1800mPa•s, and perform dehydration, impurity removal, and detoxification treatment in sequence to obtain pretreated residue; Step 2: Preparation of composite modifier: A composite system of bio-based modifier, inorganic modifier and crosslinking agent is used. The composite modifier is prepared by mass fractions of 40-50 parts bio-based modifier, 25-35 parts inorganic modifier, 10-15 parts crosslinking agent and 5-10 parts auxiliary modifier. Step 3: Prepolymerization reaction: Heat the pretreated residue to 180-200℃, add 0.8-1.2% of its mass of polymerization catalyst, control the stirring speed to 100-120 r / min and the reaction pressure to 0.12-0.15 MPa, and carry out the prepolymerization reaction for 60-90 min to obtain the prepolymerized product; Step 4: Composite Modification Reaction: Add 15-25% by weight of the composite modifier to the prepolymer product, and simultaneously add 0.3-0.5% by weight of the compatibility accelerator to the prepolymer product. Control the reaction temperature at 210-230℃, the stirring speed at 180-220 r / min, and the reaction pressure at 0.18-0.22 MPa. React for 90-120 min to obtain modified crude asphalt. Step 5: UV protection modification: Add 0.5-0.8% by weight of UV absorber to the modified crude asphalt, control the temperature at 180-190℃ and the stirring speed at 120-150 r / min, and stir for 30-40 min to obtain UV-protected modified asphalt. Step 6: Homogenization, cooling and molding: After the UV-protected modified asphalt is homogenized by grinding with a colloid mill, it is cooled to 80-100℃ at a rate of 5-8℃ / min and then molded to obtain the modified plant asphalt product.

[0008] Preferably, in step 1, the specific operation of the dehydration treatment is as follows: the distillation residue is fed into a vacuum dehydrator, the vacuum degree is controlled at 0.07-0.09MPa, the temperature at 105-115℃, and the stirring speed at 60-80r / min, and the dehydration is carried out for 25-35min until the moisture content of the residue is ≤3%; the water vapor generated during dehydration is condensed and recovered and then recycled as process water.

[0009] Preferably, in step 1, the specific operation of the impurity removal process is as follows: the dehydrated residue is fed into a high-speed centrifuge, the rotation speed is controlled at 3000-3500 r / min and the temperature at 80-90℃, and centrifuged for 15-20 min to remove mechanical impurities with a particle size ≥5μm; the impurities separated by centrifugation are collected and sent to a hazardous waste disposal center for harmless treatment.

[0010] Preferably, in step 1, the specific operation of the detoxification treatment is as follows: add 3-5% of the modified zeolite by mass to the impurity removal residue, stir evenly, and then send it into a constant temperature reactor, control the temperature at 120-130℃, the stirring speed at 50-70 r / min, and react for 40-60 min.

[0011] Preferably, the modified zeolite is prepared by soaking in 5% hydrochloric acid solution for 2 hours, washing with water until neutral, and then drying at 110°C for 3 hours.

[0012] Preferably, in step 2, the bio-based modifier is a bio-ester obtained from waste vegetable oil residue through transesterification; the inorganic modifier is obtained by modifying nano-montmorillonite with 3% silane coupling agent KH-550; the crosslinking agent is diphenylmethane diisocyanate; and the co-modifier is polyethylene glycol 400.

[0013] Preferably, in step 2, the preparation method of the composite modifier is as follows: heat the bio-based modifier to 60-70℃, add the auxiliary modifier and stir evenly, slowly add the inorganic modifier, control the stirring speed to 150-200 r / min, stir for 30-40 min, then add the crosslinking agent, raise the temperature to 80-90℃, and continue stirring for 20-30 min to obtain a uniformly dispersed composite modifier.

[0014] Preferably, in step 3, the polymerization catalyst is a mixture of stannous octoate and p-toluenesulfonic acid in a mass ratio of 2:1.

[0015] Preferably, in step 4, the compatibility promoter is maleic anhydride-grafted polyethylene wax, which improves the compatibility between the composite modifier and the prepolymer product and prevents the modifier from agglomerating.

[0016] Preferably, in step 5, the ultraviolet absorber is 2-hydroxy-4-methoxybenzophenone, which is used to inhibit ultraviolet aging of asphalt during outdoor use and extend the service life of asphalt.

[0017] The advantages and beneficial effects of the process for preparing modified plant asphalt using the above-mentioned waste oil hydrolysis and distillation residue are as follows: 1. This invention achieves high-volume, harmless, and resource-based utilization of waste oil hydrolysis and distillation residue, transforming hazardous waste into high-value-added modified plant asphalt, solving the environmental pollution problems caused by residue incineration and landfill, while saving petroleum resources and native plant raw materials, which is in line with the development concept of environmental protection, energy conservation and circular economy.

[0018] 2. This invention significantly improves the comprehensive performance of modified plant asphalt through five innovative technologies: three-stage pretreatment process, composite modification system, prepolymerization reaction, introduction of compatibility accelerator, and UV protection modification. Its high-temperature stability, low-temperature crack resistance, anti-aging performance, and UV aging resistance all meet the first-class standard for road asphalt. It can be widely used in road paving, waterproofing projects, and other fields, adapting to different working conditions and extending its service life by more than 30%.

[0019] 3. The introduction of the compatibility accelerator in this invention fills the technical gap of poor compatibility between the modifier and the residue, and the ultraviolet protection modification fills the gap of no special ultraviolet protection for plant asphalt, further enhancing the creativity and practicality of the technology.

[0020] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0021] The technical solution of the present invention will be further described below through embodiments.

[0022] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0023] The following examples are not intended to limit the invention, but are only for illustration. Unless otherwise specified, the experimental methods used in the following examples are generally performed under conventional conditions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0024] Example 1 The specific steps of the process for preparing modified plant bitumen from waste oil hydrolysis and distillation residue are as follows: Step 1: Pretreatment: Select waste oil hydrolysis distillation residue (12% water content, 100 mg KOH / g acid value, 1500 mPa•s viscosity (25℃)), send it to a vacuum dehydrator, control the vacuum degree to 0.08 MPa, temperature to 110℃, and stirring speed to 70 r / min, dehydrate for 30 min, and obtain a dehydrated residue with a water content of 2.5%; send the dehydrated residue to a high-speed centrifuge, centrifuge at 3200 r / min and 85℃ for 18 min to remove mechanical impurities; add 4% by mass of modified zeolite (modified zeolite is prepared by soaking in 5% hydrochloric acid solution for 2 h, washing with water until neutral, and drying at 110℃ for 3 h) to the dehydrated residue, send it to a constant temperature reactor, react at 125℃ and 60 r / min for 50 min, and obtain a pretreated residue (heavy metal content 0.08 mg / kg, toxic organic impurity removal rate 96%).

[0025] By employing a three-stage pretreatment process of "dehydration-impurity removal-detoxification," and targeting the characteristics of waste oil hydrolysis and distillation residues, this technology utilizes modified zeolite adsorption to achieve efficient removal of trace heavy metals and toxic organic impurities. This solves the secondary pollution risk associated with residue utilization in existing technologies, while also improving the purity of the residues and laying the foundation for subsequent modification reactions. Existing technologies often only perform simple dehydration and impurity removal without considering the detoxification treatment of the residues, thus failing to achieve harmless utilization and resulting in high impurity content that degrades asphalt performance.

[0026] Step 2: Preparation of composite modifier: Take 45 parts by mass of bio-based modifier (ester exchange product of waste vegetable oil), 30 parts by mass of modified nano-montmorillonite (nano-montmorillonite modified with 3% silane coupling agent KH-550), 12 parts by mass of diphenylmethane diisocyanate (MDI), and 8 parts by mass of polyethylene glycol 400; heat the bio-based modifier to 65℃, add polyethylene glycol 400, stir evenly, add modified nano-montmorillonite, stir at 180 r / min for 35 min, then add MDI, heat to 85℃, stir for 25 min to obtain composite modifier.

[0027] The design incorporates a "bio-based + inorganic + cross-linking" composite modification system, overcoming the limitations of existing single-modifier technologies. The bio-based modifier (prepared from waste vegetable oil residue) further enhances resource utilization, the inorganic modifier strengthens high-temperature stability, and the cross-linking agent constructs a three-dimensional network structure to improve overall stability. The synergistic effect of these three modifiers simultaneously improves the high-temperature, low-temperature, and anti-aging properties of asphalt, solving the pain point of uneven performance of existing plant-based asphalt that cannot meet engineering requirements. Existing technologies often use single modifiers, making it difficult to balance various properties and resulting in limited modification effects.

[0028] Step 3: Prepolymerization reaction: The pretreated residue is fed into the reactor, heated to 190°C, and 1.0% of the polymerization catalyst (stannous octoate: p-toluenesulfonic acid = 2:1) is added. The reaction is carried out at 110 r / min and 0.13 MPa for 75 min to obtain the prepolymerized product.

[0029] By introducing a prepolymerization reaction step, the effective components in the residue are polymerized in advance to form asphaltene precursors. This method differs from the direct mixing and modification method in existing technologies, significantly improving the compatibility and reaction sufficiency of the modifier and residue, reducing the difficulty of modification, and improving the stability of product performance. Existing technologies do not include a prepolymerization step, resulting in uneven dispersion and insufficient reaction between the modifier and residue, which can easily lead to problems such as stratification and accelerated aging.

[0030] Step 4: Composite modification reaction: Add 20% by weight of the composite modifier to the prepolymer product, and simultaneously add 0.4% by weight of maleic anhydride grafted polyethylene wax to the prepolymer product. Control the temperature at 220℃, 200r / min, and 0.20MPa, and react for 105min to obtain modified crude asphalt.

[0031] The addition of a compatibility accelerator (maleic anhydride-grafted polyethylene wax) effectively improves the compatibility between the composite modifier and the prepolymer product, avoids the problems of modifier agglomeration and uneven dispersion, further enhances the structural stability and comprehensive performance of asphalt, and fills the technical gap of poor compatibility of the modification system in the existing technology; the existing technology does not consider the compatibility between the modifier and the residue, resulting in large fluctuations in asphalt performance and short service life.

[0032] Step 5: UV protection modification: Add 0.6% by weight of 2-hydroxy-4-methoxybenzophenone (UV-9) UV absorber to the modified crude asphalt, control the temperature at 185℃ and 130r / min, and stir for 35min to obtain UV-protected modified asphalt.

[0033] The new UV protection modification step introduces a UV absorber (UV-9) to specifically address the problems of UV aging and cracking that easily occur when plant-based asphalt is used outdoors, extending the service life of asphalt by more than 30%, and filling the gap in the existing technology where plant-based asphalt does not have a specific UV protection modification; the existing technology does not have a specific treatment for the UV aging of asphalt, which limits its outdoor application range.

[0034] Step 6: Homogenization, cooling and molding: The UV-protected modified asphalt is fed into a colloid mill and ground at 3200 r / min for 25 min. Then it is cooled to 90°C at a rate of 6°C / min and fed into a molding machine to be pressed into blocks to obtain the modified plant asphalt product.

[0035] Example 2 The specific steps of the process for preparing modified plant bitumen from waste oil hydrolysis and distillation residue are as follows: Step 1: Pretreatment: Select waste oil hydrolysis distillation residue (10% water content, 80 mg KOH / g acid value, viscosity (25℃) 1200 mPa•s), send it to a vacuum dehydrator, control the vacuum degree to 0.07 MPa, temperature to 105℃, and stirring speed to 60 r / min, dehydrate for 25 min, and obtain a dehydrated residue with a water content of 2.8%; send the dehydrated residue to a high-speed centrifuge, centrifuge at 3000 r / min and 80℃ for 15 min to remove mechanical impurities; add 3% by mass of modified zeolite (modified zeolite is prepared by soaking in 5% hydrochloric acid solution for 2 h, washing with water until neutral, and drying at 110℃ for 3 h) to the dehydrated residue, send it to a constant temperature reactor, react at 120℃ and 50 r / min for 40 min, and obtain a pretreated residue (heavy metal content 0.09 mg / kg, toxic organic impurity removal rate 95%).

[0036] Step 2: Preparation of composite modifier: Take 40 parts by mass of bio-based modifier, 25 parts by mass of modified nano-montmorillonite (nano-montmorillonite modified with 3% silane coupling agent KH-550), 10 parts by mass of MDI, and 5 parts by mass of polyethylene glycol 400; heat the bio-based modifier to 60℃, add polyethylene glycol 400, stir evenly, add modified nano-montmorillonite, stir at 150 r / min for 30 min, then add MDI, heat to 80℃, stir for 20 min to obtain composite modifier.

[0037] Step 3: Prepolymerization reaction: The pretreated residue is fed into the reactor, heated to 180°C, and 0.8% of the polymerization catalyst (stannous octoate: p-toluenesulfonic acid = 2:1) is added. The reaction is carried out at 100 r / min and 0.12 MPa for 60 min to obtain the prepolymerized product.

[0038] Step 4: Composite modification reaction: Add 15% by weight of the composite modifier to the prepolymer product, and simultaneously add 0.3% by weight of maleic anhydride-grafted polyethylene wax to the prepolymer product. Control the temperature at 210℃, 180r / min, and 0.18MPa, and react for 90min to obtain modified crude asphalt.

[0039] Step 5: UV protection modification: Add 0.5% by weight of UV-9 UV absorber to the modified crude asphalt, control the temperature at 180℃ and 120r / min, and stir for 30min to obtain UV-protected modified asphalt.

[0040] Step 6: Homogenization, cooling and molding: The UV-protected modified asphalt is fed into a colloid mill and ground at 3000 r / min for 20 min. Then it is cooled to 80°C at a rate of 5°C / min and fed into a molding machine to form granules, thus obtaining the modified plant asphalt product.

[0041] Example 3 The specific steps of the process for preparing modified plant bitumen from waste oil hydrolysis and distillation residue are as follows: Step 1: Pretreatment: Select waste oil hydrolysis distillation residue (15% water content, 120 mg KOH / g acid value, 1800 mPa•s viscosity (25℃)), send it to a vacuum dehydrator, control the vacuum degree to 0.09 MPa, temperature to 115℃, and stirring speed to 80 r / min, dehydrate for 35 min, and obtain a dehydrated residue with a water content of 2.2%; send the dehydrated residue to a high-speed centrifuge, centrifuge at 3500 r / min and 90℃ for 20 min to remove mechanical impurities; add 5% by mass of modified zeolite (modified zeolite is prepared by soaking in 5% hydrochloric acid solution for 2 h, washing with water until neutral, and drying at 110℃ for 3 h) to the dehydrated residue, send it to a constant temperature reactor, react at 130℃ and 70 r / min for 60 min, and obtain a pretreated residue (heavy metal content 0.07 mg / kg, toxic organic impurity removal rate 97%).

[0042] Step 2: Preparation of composite modifier: Take 50 parts by mass of bio-based modifier, 35 parts by mass of modified nano-montmorillonite (nano-montmorillonite modified with 3% silane coupling agent KH-550), 15 parts by mass of MDI, and 10 parts by mass of polyethylene glycol 400; heat the bio-based modifier to 70°C, add polyethylene glycol 400, stir evenly, add modified nano-montmorillonite, stir at 200 r / min for 40 min, then add MDI, heat to 90°C, stir for 30 min to obtain composite modifier.

[0043] Step 3: Prepolymerization reaction: The pretreated residue is fed into the reactor, heated to 200°C, and 1.2% of its mass of polymerization catalyst (stannous octoate: p-toluenesulfonic acid = 2:1) is added. The reaction is carried out at 120 r / min and 0.15 MPa for 90 min to obtain the prepolymerized product.

[0044] Step 4: Composite modification reaction: Add 25% by mass of the composite modifier to the prepolymer product, and simultaneously add 0.5% by mass of maleic anhydride-grafted polyethylene wax to the prepolymer product. Control the temperature at 230℃, 220r / min, and 0.22MPa, and react for 120min to obtain modified crude asphalt.

[0045] Step 5: UV protection modification: Add 0.8% by weight of UV-9 UV absorber to the modified crude asphalt, control the temperature at 190℃ and 150r / min, and stir for 40min to obtain UV-protected modified asphalt.

[0046] Step 6: Homogenization, cooling and molding: The UV-protected modified asphalt is fed into a colloid mill and ground at 3500 r / min for 30 min. Then it is cooled to 100℃ at a rate of 8℃ / min and fed into a molding machine to be pressed into blocks to obtain the modified plant asphalt product.

[0047] Comparative Example 1 (without detoxification treatment) The process steps are basically the same as in Example 1, except that in step 1 only dehydration and impurity removal are performed, and no modified zeolite is added for detoxification. The remaining process parameters are the same as in Example 1, and modified plant asphalt is prepared.

[0048] Comparative Example 2 (Single Modifier) The process steps are basically the same as in Example 1, except that in step 2, only a bio-based modifier is used as a single modifier (addition amount 20%), and no inorganic modifier or crosslinking agent is added. The remaining process parameters are the same as in Example 1, and modified plant asphalt is prepared.

[0049] Comparative Example 3 (without prepolymerization reaction) The process steps are basically the same as in Example 1, except that the prepolymerization reaction in step 3 is omitted, and the pretreated residue is directly mixed with the composite modifier and compatibility accelerator to carry out the modification reaction. The remaining process parameters are the same as in Example 1, and modified plant asphalt is prepared.

[0050] Comparative Example 4 (without compatibility accelerator) The process steps are basically the same as in Example 1, except that no compatibility accelerator is added in step 4, and the remaining process parameters are the same as in Example 1, thus preparing modified plant asphalt.

[0051] Comparative Example 5 (without UV protection modification) The process steps are basically the same as in Example 1, except that the UV protection modification in step 5 is omitted, while the remaining process parameters are the same as in Example 1, and modified plant asphalt is prepared.

[0052] The asphalt products prepared in Examples 1-3 and Comparative Examples 1-5 of this invention were subjected to performance tests in accordance with the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011) and the Enterprise Standard for Plant Asphalt (Q / HBHS05-2020). The test items included: penetration (25℃, 0.1mm), softening point (℃), ductility (10℃, cm), penetration ratio after aging (%), ductility retention rate after UV aging (%), heavy metal content (mg / kg), and residue utilization rate (%). The test results are shown in Table 1 below: Table 1 Test Results

[0053] Analysis of test results: 1. The product performance of Examples 1-3 is superior to all comparative examples. The penetration, softening point, ductility and penetration ratio after aging all meet the first-class standard for road asphalt. The ductility retention rate after UV aging is ≥86%, the heavy metal content is far lower than the national standard (≤1.0mg / kg), and the residue utilization rate reaches 78-82%. It realizes high-volume and harmless utilization of residue, and solves the pain points of poor compatibility and severe UV aging in the existing technology.

[0054] 2. Compared with Example 1, Comparative Example 1 (without detoxification) had excessive heavy metal content and all product performance decreased, indicating that detoxification treatment can not only render the residue harmless, but also improve the performance of asphalt products.

[0055] 3. Compared with Example 1, Comparative Example 2 (single modifier) ​​showed a significant decrease in softening point and penetration ratio after aging, indicating that a single modifier cannot simultaneously achieve the high-temperature stability and anti-aging properties of asphalt, while the composite modification system of the present invention has significant advantages.

[0056] 4. Compared with Example 1, Comparative Example 3 (without prepolymerization reaction) showed a significant decrease in ductility and penetration ratio after aging, indicating that the prepolymerization reaction can effectively improve the modification effect and product stability.

[0057] 5. Compared with Example 1, Comparative Example 4 (without compatibility accelerator) showed a decrease in all properties, especially a significant decrease in ductility, indicating that the compatibility accelerator can effectively improve the compatibility between the modifier and the residue, prevent agglomeration, and improve the performance of asphalt.

[0058] 6. Compared with Example 1, Comparative Example 5 (without UV protection modification) had a ductility retention rate of only 62% after UV aging, which was much lower than 88% in Example 1. This indicates that UV protection modification can significantly improve the UV aging resistance of asphalt and extend its service life.

[0059] Therefore, the present invention adopts the above-mentioned process for preparing modified plant asphalt from waste oil hydrolysis and distillation residue. Through an integrated process of pretreatment-composite modification-synergistic stabilization-ultraviolet protection, it achieves high-volume and harmless utilization of residue, while significantly improving the comprehensive performance and service life of plant asphalt. Moreover, the process is simple, energy-efficient, and can be industrialized for continuous production, overcoming the shortcomings of existing technologies, highlighting creativity and significant progress, and further improving resource utilization.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A process for preparing modified plant pitch from waste oil hydrolysis rectification residue, characterized in that, Includes the following steps: Step 1: Pretreatment of waste oil hydrolysis distillation residue: Select waste oil hydrolysis distillation residue with water content ≤15%, acid value 80-120mgKOH / g, and viscosity 1200-1800mPa•s, and perform dehydration, impurity removal, and detoxification treatment in sequence to obtain pretreated residue; Step 2: Preparation of composite modifier: A composite system of bio-based modifier, inorganic modifier and crosslinking agent is used. The composite modifier is prepared by mass fractions of 40-50 parts bio-based modifier, 25-35 parts inorganic modifier, 10-15 parts crosslinking agent and 5-10 parts auxiliary modifier. Step 3: Prepolymerization reaction: Heat the pretreated residue to 180-200℃, add 0.8-1.2% of its mass of polymerization catalyst, control the stirring speed to 100-120 r / min and the reaction pressure to 0.12-0.15 MPa, and carry out the prepolymerization reaction for 60-90 min to obtain the prepolymerized product; Step 4: Composite Modification Reaction: Add 15-25% by weight of the composite modifier to the prepolymer product, and simultaneously add 0.3-0.5% by weight of the compatibility accelerator to the prepolymer product. Control the reaction temperature at 210-230℃, the stirring speed at 180-220 r / min, and the reaction pressure at 0.18-0.22 MPa. React for 90-120 min to obtain modified crude asphalt. Step 5: UV protection modification: Add 0.5-0.8% by weight of UV absorber to the modified crude asphalt, control the temperature at 180-190℃ and the stirring speed at 120-150 r / min, and stir for 30-40 min to obtain UV-protected modified asphalt. Step 6: Homogenization, cooling and molding: After the UV-protected modified asphalt is homogenized by grinding with a colloid mill, it is cooled to 80-100℃ at a rate of 5-8℃ / min and then molded to obtain the modified plant asphalt product.

2. The process for preparing modified plant pitch from waste oil hydrolysis rectification residue according to claim 1, characterized in that: In step 1, the specific operation of dehydration is as follows: the distillation residue is fed into a vacuum dehydrator, the vacuum degree is controlled at 0.07-0.09MPa, the temperature at 105-115℃, and the stirring speed at 60-80r / min, and dehydration is carried out for 25-35min until the moisture content of the residue is ≤3%; the water vapor generated during dehydration is condensed and recovered and then recycled as process water.

3. The process for preparing modified plant asphalt from waste oil hydrolysis and distillation residue according to claim 1, characterized in that: In step 1, the specific operation of the impurity removal process is as follows: the dehydrated residue is fed into a high-speed centrifuge, the rotation speed is controlled at 3000-3500 r / min and the temperature is 80-90℃, and centrifuged for 15-20 min to remove mechanical impurities with a particle size ≥5μm; the impurities separated by centrifugation are collected and sent to a hazardous waste disposal center for harmless treatment.

4. The process for preparing modified plant bitumen from waste oil hydrolysis and distillation residue according to claim 1, characterized in that: In step 1, the specific operation of the detoxification treatment is as follows: add 3-5% of the modified zeolite by mass to the impurity removal residue, stir evenly, and then send it into a constant temperature reactor. Control the temperature at 120-130℃, the stirring speed at 50-70 r / min, and react for 40-60 min.

5. The process for preparing modified plant bitumen from waste oil hydrolysis and distillation residue according to claim 4, characterized in that: Modified zeolite was prepared by soaking in 5% hydrochloric acid solution for 2 hours, washing with water until neutral, and then drying at 110℃ for 3 hours.

6. The process for preparing modified plant asphalt from waste oil hydrolysis and distillation residue according to claim 1, characterized in that: In step 2, the bio-based modifier is a bio-ester obtained from waste vegetable oil residue through transesterification; the inorganic modifier is nano-montmorillonite modified with 3% silane coupling agent KH-550; the crosslinking agent is diphenylmethane diisocyanate; and the co-modifier is polyethylene glycol 400.

7. The process for preparing modified plant bitumen from waste oil hydrolysis and distillation residue according to claim 1, characterized in that: In step 2, the preparation method of the composite modifier is as follows: heat the bio-based modifier to 60-70℃, add the auxiliary modifier and stir evenly, slowly add the inorganic modifier, control the stirring speed to 150-200r / min, stir for 30-40min, then add the crosslinking agent, raise the temperature to 80-90℃, and continue stirring for 20-30min to obtain a uniformly dispersed composite modifier.

8. The process for preparing modified plant asphalt from waste oil hydrolysis and distillation residue according to claim 1, characterized in that: In step 3, the polymerization catalyst is a mixture of stannous octoate and p-toluenesulfonic acid in a mass ratio of 2:

1.

9. The process for preparing modified plant bitumen from waste oil hydrolysis and distillation residue according to claim 1, characterized in that: In step 4, the compatibility accelerator is maleic anhydride-grafted polyethylene wax, which improves the compatibility between the composite modifier and the prepolymer product and prevents the modifier from agglomerating.

10. The process for preparing modified plant bitumen from waste oil hydrolysis and distillation residue according to claim 1, characterized in that: In step 5, the UV absorber is 2-hydroxy-4-methoxybenzophenone, which is used to inhibit UV aging of asphalt during outdoor use and extend the service life of asphalt.

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