A method for preparing modified asphalt

Abstract

This invention discloses a method for preparing modified asphalt. The method includes the following steps: (1) mixing vacuum residue with a compatibilizer and a polymer, heating for the first time, and shearing; (2) adding a crosslinking accelerator to the material after shearing in step (1) and introducing oxygen-containing gas, heating for the second time, and carrying out a development reaction; (3) after cooling the material obtained in step (2), adding a crosslinking terminator and introducing oxygen-containing gas, and carrying out a reaction to obtain modified asphalt; wherein, the crosslinking accelerator is 1,1-diphenylmethylene-4-triphenylmethyl-2,5-cyclohexadiene. This invention keeps the performance of polymer-modified asphalt at the required performance indicators, achieving the goal of controllable modification degree. This solves the problem that the polymer will continue to crosslink, and the viscosity of the asphalt will further increase.

Description

Technical Field

[0001] This invention relates to the field of asphalt, and specifically to a method for preparing modified asphalt. Background Technology

[0002] SBS-modified asphalt is currently the most widely used polymer-modified asphalt. A certain amount of SBS modifier is added to vacuum residue, and the SBS is uniformly dispersed through shearing and stirring. Simultaneously, a specific stabilizer is added to crosslink the vacuum residue and SBS, significantly improving the high and low temperature performance of the asphalt. However, there are also challenging problems in the production process of polymer-modified asphalt. After a certain development time, the modified asphalt meets the performance requirements, but at this point, many active sites still exist in the polymer. At a certain temperature, the crosslinking reaction of the polymer continues, causing the viscosity of the modified asphalt to continuously increase during subsequent storage and transportation, resulting in the modified asphalt exceeding the required performance specifications, thus affecting transportation and use.

[0003] CN103044932A discloses a method for preparing modified asphalt using raw materials with low asphaltene content. This method uses residual oil or deoiled asphalt, or a mixture thereof, with an aromatic hydrocarbon content of less than 30% and an asphaltene content of less than 5%, and a boiling point above 350℃ at atmospheric pressure, as raw materials. The asphaltene content is increased through thermal cracking, and then the residue from the bottom of the distillation column with a boiling point above 350℃ is obtained as a high-asphaltene content component. The high-asphaltene content component is then reacted with 1%-20% aromatic oil compatibilizer through shear dispersion and high-temperature stirring to prepare SBS-modified asphalt. However, this method cannot improve the hydrocarbon molecular structure of the asphalt, and therefore cannot improve the compatibility between the asphalt and SBS. Summary of the Invention

[0004] To address the aforementioned problems, this invention aims to provide a method for preparing modified asphalt. This invention maintains the modified asphalt's properties at the desired performance levels, achieving controllable modification. This solves the problem of continued polymer crosslinking and further increase in asphalt viscosity.

[0005] This invention provides a method for preparing modified asphalt, comprising the following steps:

[0006] (1) Mix vacuum residue with compatibilizer and polymer, heat for the first time, and shear;

[0007] (2) Add crosslinking promoter to the material after shearing in step (1) and pass in oxygen-containing gas, then heat for a second time to carry out the development reaction;

[0008] (3) After the material obtained in step (2) is cooled down, a crosslinking terminator is added and oxygen-containing gas is introduced to carry out the reaction and obtain modified asphalt;

[0009] The crosslinking accelerator is 1,1-diphenylmethylene-4-triphenylmethyl-2,5-cyclohexadiene.

[0010] Furthermore, in step (1), the properties of the vacuum residue are as follows: the penetration at 25°C is 100-200 0.1 mm.

[0011] Further, in step (1), the compatibilizer is one or a mixture of several of the following: reduced-strength extracted oil, furfural refined extracted oil, phenol refined extracted oil, or catalytic cracking slurry.

[0012] Further, in step (1), the polymer is SBS (styrene-butadiene-styrene block copolymer).

[0013] Furthermore, in step (1), after the first heating, the temperature is 140-170℃.

[0014] Further, in step (1), the mass ratio of the vacuum residue, compatibilizer, and polymer is 100:1-4:2-8.

[0015] Furthermore, in step (1), the first heating can be carried out in a premix tank.

[0016] Furthermore, in step (1), the shearing can be performed using methods conventional in the art, such as using a colloid mill and / or a high-speed shearing machine. The shearing speed is 5000 r / min-8000 r / min.

[0017] Further, in step (2), the crosslinking accelerator 1,1-diphenylmethylene-4-triphenylmethyl-2,5-cyclohexadiene has the following structure:

[0018]

[0019] Further, in step (2), the mass ratio of the crosslinking accelerator to the vacuum residue is 0.10-0.50:100.

[0020] Further, in step (2), the material sheared in step (1) is placed in a development tank, wherein the crosslinking promoter enters from the bottom of the development tank and the oxygen-containing gas enters from the bottom of the development tank.

[0021] Furthermore, after the second heating, the temperature is 180-220℃, and the development reaction time is 20-80 minutes. Preferably, the temperature after the second heating is 20-60℃ higher than the temperature after the first heating.

[0022] Furthermore, in steps (2) and (3), the oxygen-containing gas is independently selected from air and / or oxygen.

[0023] Furthermore, in step (2), the oxygen-containing gas is introduced at a rate of 1-10 L / min / 100 kg vacuum residue.

[0024] Furthermore, in step (3), the cooling can be achieved by passing the material obtained in step (2) through a heat exchanger. After cooling, the temperature is preferably reduced by 20-70°C compared to the temperature after the second heating.

[0025] Further, in step (3), the material obtained in step (2) is cooled and then enters the processing tower, and both the crosslinking agent and the terminator enter from the top of the processing tower, while the oxygen-containing gas enters from the bottom of the processing tower.

[0026] Further, in step (3), the crosslinking terminator is hydroquinone. The mass ratio of the crosslinking terminator to vacuum residue is 0.05-0.20:100.

[0027] Further, in step (3), the oxygen-containing gas is introduced at a rate of 1-5 L / min / 100 kg vacuum residue.

[0028] Further, in step (3), the reaction time is 10-30 min, the reaction temperature is 130-160℃, and modified asphalt is obtained after the reaction. The waste gas is discharged from the top of the treatment tower. The modified asphalt can be collected in the product tank.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] (1) The modified asphalt of the present invention incorporates a crosslinking accelerator and increases the development temperature, thereby accelerating the crosslinking speed of asphalt and polymer and shortening the reaction time.

[0031] (2) The modified asphalt of the present invention uses a crosslinking accelerator with a large delocalized conjugated system. It is a relatively stable free radical. It has an initiating effect in the high-temperature development stage, promoting the crosslinking reaction between asphalt and polymer. In the low-temperature treatment stage, as the system temperature decreases, it transforms into an inhibitory effect and stops the crosslinking reaction.

[0032] (3) During the high-temperature development stage, oxygen-containing gas has two functions. On the one hand, it acts as an initiator at high temperatures to work with crosslinking promoters to accelerate the crosslinking reaction. On the other hand, oxygen-containing gas acts as an oxidant to slightly oxidize asphalt, thereby improving the high-temperature performance and anti-aging performance of modified asphalt.

[0033] (4) During the low-temperature treatment stage, hydroquinone, the crosslinking terminator, has a polymerization inhibition function. Oxygen also becomes an excellent polymerization inhibitor. In the oxygen environment, hydroquinone is oxidized to benzoquinone, which significantly improves the efficiency of blocking free radical reactions and achieves the effect of locking up the reaction. Detailed Implementation

[0034] The technical solution of the present invention will be described in detail below with reference to the embodiments, but the present invention is not limited to the following 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.

[0035] In this invention, the parts in the comparative examples are parts by mass.

[0036] Example 1

[0037] Vacuum residue (25℃, 100mm penetration), vacuum residue extract (with compatibilizer), and SBS polymer were fed into a premix tank. The mixture was first heated to 170℃ and passed through a high-speed shear press (7000 rpm) before entering a development tank. A 1,1-diphenylmethylene-4-triphenylmethyl-2,5-cyclohexadiene crosslinking accelerator was added, and the mixture was heated to 210℃ in the second stage. Oxygen was introduced from the bottom of the development tank at a rate of 10 L / min, and the mixture was allowed to develop for 75 minutes. After heat exchange, the mixture was cooled to 150℃ and fed into a treatment tower from the top. A crosslinking terminator was added, and oxygen was introduced from the bottom of the treatment tower at a rate of 4 L / min. The mixture was treated in the treatment tower for 25 minutes before entering the product tank to obtain modified asphalt. The amounts of each raw material are shown in Table 1.

[0038] Example 2

[0039] Vacuum residue (25℃, 140 mm penetration), catalytic cracking slurry (compatibilizer), and polymer SBS are fed into a premix tank. The mixture is first heated to 165℃, then passed through a high-speed shear press (6000 rpm) before entering a development tank. A 1,1-diphenylmethylene-4-triphenylmethyl-2,5-cyclohexadiene crosslinking accelerator is added, and the mixture is heated to 195℃ in the second stage. Oxygen is introduced from the bottom of the development tank at a rate of 7 L / min, and development lasts for 40 minutes. After heat exchange, the mixture is cooled to 145℃ and fed into a treatment tower from the top. A crosslinking terminator is added, and oxygen is introduced from the bottom of the treatment tower at a rate of 2 L / min. The mixture is treated in the tower for 15 minutes before entering the product tank to obtain modified asphalt. The amounts of each raw material are shown in Table 1.

[0040] Example 3

[0041] Vacuum residue (25℃, 160 mm penetration), phenol-refined extract oil (compatibilizer), and SBS polymer were fed into a premix tank. The mixture was first heated to 160℃ and passed through a high-speed shear press (5000 rpm) before entering a development tank. A 1,1-diphenylmethylene-4-triphenylmethyl-2,5-cyclohexadiene crosslinking accelerator was added, and the mixture was heated to 180℃ in the second stage. Oxygen was introduced from the bottom of the development tank at a rate of 3 L / min, and the mixture was allowed to develop for 30 minutes. After heat exchange, the mixture was cooled to 140℃ and fed into a treatment tower from the top. A crosslinking terminator was added, and oxygen was introduced from the bottom of the treatment tower at a rate of 1 L / min. The mixture was treated in the tower for 10 minutes before entering the product tank to obtain modified asphalt. The amounts of each raw material are shown in Table 1.

[0042] Example 4

[0043] Vacuum residue (25℃, 170 mm penetration), furfural refined extract (compatibilizer), and SBS polymer were fed into a premix tank. The mixture was first heated to 160℃ and passed through a high-speed shear mill (6000 rpm) before entering a development tank. A 1,1-diphenylmethylene-4-triphenylmethyl-2,5-cyclohexadiene crosslinking accelerator was added, and the mixture was heated to 185℃ in the second stage. Oxygen was introduced from the bottom of the development tank at a rate of 2 L / min, and the mixture was allowed to develop for 45 minutes. After heat exchange, the mixture was cooled to 140℃ and fed into a treatment tower from the top. A crosslinking terminator was added, and oxygen was introduced from the bottom of the treatment tower at a rate of 3 L / min. The mixture was treated in the tower for 30 minutes before entering a product tank to obtain modified asphalt. The amounts of each raw material are shown in Table 1.

[0044] Example 5

[0045] Vacuum residue (25℃, 180 mm penetration), vacuum residue extract (with compatibilizer), and SBS polymer were fed into a premix tank. The mixture was first heated to 145℃ and passed through a high-speed shear press (5500 rpm) before entering a development tank. A 1,1-diphenylmethylene-4-triphenylmethyl-2,5-cyclohexadiene crosslinking accelerator was added, and the mixture was heated to 190℃ in the second stage. Oxygen was introduced from the bottom of the development tank at a rate of 5 L / min, and the mixture was allowed to develop for 25 minutes. After heat exchange, the mixture was cooled to 135℃ and fed into the top of a treatment tower. A crosslinking terminator was added, and oxygen was introduced from the bottom of the treatment tower at a rate of 5 L / min. The mixture was treated in the tower for 20 minutes before entering the product tank to obtain modified asphalt. The amounts of each raw material are shown in Table 1.

[0046] Example 6

[0047] Vacuum residue (25℃, 130 mm penetration), furfural refined extract (compatibilizer), and SBS polymer were fed into a premix tank. The mixture was first heated to 160℃ and passed through a high-speed shear press (7000 rpm) before entering a development tank. A 1,1-diphenylmethylene-4-triphenylmethyl-2,5-cyclohexadiene crosslinking accelerator was added, and the mixture was heated to 205℃ in the second stage. Oxygen was introduced from the bottom of the development tank at a rate of 8 L / min, and the mixture was allowed to develop for 60 minutes. After heat exchange, the mixture was cooled to 150℃ and fed into the top of a treatment tower. A crosslinking terminator was added, and oxygen was introduced from the bottom of the treatment tower at a rate of 3 L / min. The mixture was treated in the tower for 25 minutes before entering the product tank to obtain modified asphalt. The amounts of each raw material are shown in Table 1.

[0048] Table 1 shows the addition amounts of each raw material in the modified asphalt of Examples 1-6.

[0049] Raw materials (kg) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 vacuum residue 100 100 100 100 100 100 compatibilizer 4 3 3 2 1 3 polymer 8 6 3 4 2.5 7 Crosslinking accelerator 0.50 0.30 0.15 0.20 0.40 0.30 Crosslinking terminator 0.20 0.10 0.10 0.05 0.15 0.20

[0050] Comparative Example 1

[0051] 100 parts of vacuum residue oil with a penetration of 100 mm at 25°C, 4.0 parts of vacuum residue oil extracted from line 4 (compatibilizer), and 8 parts of polymer SBS were mixed, heated to 170°C, and after being sheared and crushed by a colloid mill or shear machine, the mixture was put into a development tank. 0.50 parts of conventional sulfur crosslinking agent were added, the temperature was raised to 210°C, and the mixture was stirred and developed for 100 min to obtain conventional SBS modified asphalt.

[0052] Comparative Example 2

[0053] 100 parts of vacuum residue oil with a penetration of 140 mm at 25°C, 3.0 parts of catalytic cracking slurry oil (composite agent), and 6 parts of polymer SBS were mixed and heated to 165°C. After being sheared and crushed by a colloid mill or shearing machine, the mixture was put into a development tank. 0.3 parts of conventional sulfur crosslinking agent were added and the temperature was raised to 195°C. The mixture was stirred and developed for 55 minutes to obtain conventional SBS modified asphalt.

[0054] Comparative Example 3

[0055] 100 parts of vacuum residue oil with a penetration of 130 mm at 25°C, 3.0 parts of furfural refined extract oil (compatibility agent), and 7.0 parts of polymer SBS were mixed, heated to 160°C, and after being sheared and crushed by a colloid mill or shear machine, the mixture was put into a development tank. 0.3 parts of conventional sulfur crosslinking agent were added, the temperature was raised to 205°C, and the mixture was stirred and developed for 60 minutes to obtain conventional SBS modified asphalt.

[0056] Detection method:

[0057] Storage tests were conducted on the SBS modified asphalt from Examples 1-6 and Comparative Examples 1-3. The test conditions were set as follows: storage temperature 163℃, storage time 7d, penetration (25℃) and viscosity at 135℃ were measured according to JTGE20-2011, and the test results are shown in Table 2.

[0058] Table 2. Changes in properties of Examples 1-6 and Comparative Examples 1-3 before and after 7 days of storage.

[0059]

[0060] The specific embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for producing a modified asphalt, characterized by, The method comprises the following steps: (1) mixing the vacuum residue with a compatible agent and a polymer, and performing shearing by first heating; (2) adding a crosslinking accelerator to the sheared material of step (1) and introducing an oxygen-containing gas, and performing a development reaction by second heating; (3) after cooling the material obtained in step (2), adding a crosslinking terminator and introducing an oxygen-containing gas, and performing a reaction to obtain modified asphalt; The crosslinking accelerator is 1,1-benzhydrylidene-4-trityl-2,5-cyclohexadiene.

2. The method of claim 1, wherein, In step (1), the vacuum residue has the following properties: a penetration of 100-200 0.1mm at 25℃.

3. The method of claim 1, wherein, In step (1), the compatible agent is one or a mixture of several of vacuum four-line extracted oil, furfural refined extracted oil, phenol refined extracted oil, or catalytic cracking slurry.

4. The method of claim 1, wherein, In step (1), the polymer is SBS.

5. The method of claim 1, wherein, In step (1), after the first heating, the temperature is 140-170℃.

6. The method of claim 1, wherein, In step (1), the mass ratio of the vacuum residue, the compatible agent, and the polymer is 100:1-4:2-8.

7. The method of claim 1, wherein, The structure of the crosslinking accelerator 1,1-benzhydrylidene-4-trityl-2,5-cyclohexadiene is as follows: 。 8. The method of claim 1, wherein, In step (2), the mass ratio of the crosslinking accelerator to the vacuum residue is 0.10-0.50:

100.

9. The method of claim 1, wherein, After the second heating, the temperature is 180-220℃, and the development reaction time is 20-80min.

10. The method of claim 9, wherein, The temperature after the second heating is 20-60℃ higher than the temperature after the first heating.

11. The method of claim 1, wherein, In steps (2) and (3), the oxygen-containing gas is independently selected from air and / or oxygen.

12. The method of claim 1 or 11, wherein, In step (2), the amount of the oxygen-containing gas introduced is 1-10L / min / 100kg of the vacuum residue; and / or, In step (3), the amount of the oxygen-containing gas introduced is 1-5L / min / 100kg of the vacuum residue.

13. The method of claim 1, wherein, In step (3), the cooling is performed by heat exchange of the material obtained in step (2) through a heat exchanger, and after the cooling, the temperature is reduced by 20-70℃ compared with the temperature after the second heating.

14. The method of claim 1, wherein, In step (3), the crosslinking terminator is hydroquinone; and the mass ratio of the crosslinking terminator to the vacuum residue is 0.05-0.20:

100.

15. The method of claim 1, wherein, In step (3), the reaction time is 10-30min, and the reaction temperature is 130-160℃.

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