Preparation method of asphalt warm mixing agent capable of improving low-temperature toughness of asphalt

Abstract

The invention belongs to the technical field of asphalt warm mixing agents, and particularly relates to a preparation method of an asphalt warm mixing agent capable of improving low-temperature toughness of asphalt. Aiming at the problem that the brittleness of asphalt is increased under a low-temperature condition caused by an asphalt warm-mixing agent still cannot be overcome in the prior art, the invention provides the preparation method of the asphalt warm-mixing agent capable of improving the low-temperature toughness of the asphalt, which comprises the following steps of: reacting according to steps to obtain an intermediate product e; mixing the intermediate product e with an initiator, and reacting with oxygen under heating and pressurizing conditions to obtain an intermediate product f; mixing and reacting the intermediate product f with a weakly alkaline substance to obtain an intermediate product g; and melting and uniformly mixing the intermediate product g and the intermediate product e to obtain the warm mixing agent product. The intermediate product e is further subjected to oxidation initiation to obtain an intermediate product g, and the intermediate product e and the intermediate product g are compounded to obtain the warm mixing agent, so that the finally obtained warm mixing agent contains part of polar bonds such as lipids, and the low-temperature brittleness, toughness and performance of asphalt can be effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of asphalt warm mix agents, and in particular relates to a method for preparing an asphalt warm mix agent capable of improving the low-temperature toughness of asphalt. Background Art

[0002] In recent years, my country's expressways have developed rapidly, and asphalt pavement has become the preferred pavement material for expressways due to its good driving comfort and excellent performance. Hot-mix asphalt mixture technology is generally used in asphalt pavement construction. The construction temperature of this technology is relatively high (generally the heating temperature is 160-180℃), which not only consumes a lot of energy, but also produces a lot of smoke and irritating odor at high temperatures, seriously polluting the environment and endangering the health of construction workers. With the strengthening of people's environmental awareness, scientists have proposed warm-mix asphalt mixture technology, that is, adding a type of substance called warm-mix agent during the asphalt heating and mixing process, which can reduce the mixing and paving compaction temperature of asphalt, thereby reducing asphalt smoke emissions and saving energy.

[0003] The existing warm mix asphalt modifiers mainly include asphalt viscosity reducers, zeolite viscosity reduction technology, foamed asphalt warm mix technology and surfactant warm mix technology. The most basic idea is to use viscosity reducers to reduce the high temperature viscosity of the asphalt binder (without reducing its low temperature viscosity) while reducing the mixing temperature of the asphalt mixture, thereby achieving the purpose of warm mix. However, the addition of warm mix agents in the existing technology will mostly cause the asphalt to become more brittle under low temperature conditions.

[0004] For example, a Chinese invention patent discloses a high-performance asphalt warm mix agent [application number: 201810346546.0], which includes 100 parts by weight of coal tar; 1 to 20 parts by weight of nonylphenol polyoxyethylene ether; 5 to 50 parts by weight of fatty alcohol polyoxyethylene ether; and 5 to 10 parts by weight of polysulfide sulfone containing sulfonic acid groups, quaternary ammonium salt groups and hydroxyl groups at the same time; the preparation method of the polysulfide sulfone containing sulfonic acid groups, quaternary ammonium salt groups and hydroxyl groups at the same time is:

[0005] (1) 200 ml of dimethyl sulfoxide, 13 ml of toluene, 0.028 mol of 4'4-dimercaptodiphenyl sulfide, 0.03 mol of 4,4'-difluorodiphenyl sulfone, and 0.3 mol of potassium carbonate were added to a reactor equipped with a water separator in sequence, and nitrogen was passed through the reactor, and the mixture was heated to 140° C. for reaction for 4 hours to remove toluene. The mixture was then heated to 165° C. for reaction for 15 hours, and then cooled to room temperature. 0.01 mol of p-aminophenol was added, and nitrogen was passed through the reactor, and the mixture was then heated to 165° C. for reaction for 10 hours, and then cooled to room temperature. The reactants were washed three times with ethanol and deionized water, respectively, and then dried in a vacuum oven at 50° C. for 24 hours to obtain (2) In a beaker, 0.1 mol of 1,3-dibromopropane and 0.01 mol of N-methylimidazole were dissolved in 5 liters of ether, and the mixture was reacted at room temperature for one week, and then filtered to obtain a white precipitate. The white precipitate was repeatedly washed with acetone three times, and then dried in a vacuum oven at 50 degrees for 24 hours to obtain a bromine-terminated quaternary ammonium salt. (3) In a reactor, 2 g of the amino-terminated polysulfide sulfone obtained in the above step (1), 0.2 g of the bromine-terminated quaternary ammonium salt obtained in the above step (2), 0.1 g of sodium 4-(2-bromoethyl)benzenesulfonate, 0.05 g of polyvinyl alcohol, and silane coupling agent KH-560 were added in sequence. 0.3 g and 20 ml of dimethyl sulfoxide, heat to 80 degrees for 3 hours, then cool to room temperature, filter out the precipitate, wash the precipitate three times with ethanol, and dry it in a vacuum oven at 50 degrees for 24 hours to obtain a polysulfide sulfone containing sulfonic acid groups, quaternary ammonium salt groups and hydroxyl groups.

[0006] This invention has the advantages of significantly reducing construction temperature, solving fuel problems and simultaneously improving the durability and service life of asphalt, but it still does not solve the above-mentioned problems. Summary of the invention

[0007] The purpose of the present invention is to provide a method for preparing a warm mix asphalt agent that can improve the low-temperature toughness of asphalt in view of the above problems.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for preparing an asphalt warm mix agent capable of improving the low-temperature toughness of asphalt comprises the following steps:

[0010] Step 1: adding Fischer-Tropsch wax to a hydrogenation reactor, heating and pressurizing, and introducing hydrogen, and obtaining a hydrogenation product a after the reaction is completed;

[0011] Step 2: After the hydrogenation product a is melted, a mixed solvent of ketones and benzene is added, and after mixing evenly, the mixture is transferred to a crystallizer for crystallization to obtain a primary product b;

[0012] Step 3: After heating and melting the primary product b, the product is evaporated by a wiped film evaporator to obtain an intermediate product c after condensation;

[0013] Step 4: distill the intermediate product c under reduced pressure to obtain the intermediate product d;

[0014] Step 5: performing a catalytic hydrogenation reaction on the intermediate product d to obtain an intermediate product e;

[0015] Step 6: Mix the intermediate product e with the initiator, react with oxygen under heating and pressurization conditions, and after the reaction is completed, vacuum extract under nitrogen atmosphere protection to obtain the intermediate product f, the acid value of the intermediate product f is 10-90 mg KOH / g;

[0016] Step 7: Mix the intermediate product f with a weak alkaline substance to obtain an intermediate product g. The weak alkaline substance is generally sodium carbonate or ammonia water. The pH value during the reaction is about 8.

[0017] Step 8: melt and mix the intermediate product g and the intermediate product e uniformly, and granulate to obtain a warm mix product.

[0018] The Fischer-Tropsch wax may be 70#-105# Fischer-Tropsch wax, and the Fischer-Tropsch wax used in the present invention is 90# Fischer-Tropsch wax.

[0019] In the above-mentioned method for preparing a warm mix asphalt agent capable of improving the low-temperature toughness of asphalt, the heating temperature in step 1 is 300-400° C., the pressurization pressure is 0.5-10 MPa, and the hydrogen-to-oil volume ratio is 50-800.

[0020] In the above-mentioned method for preparing an asphalt warm mix agent capable of improving the low-temperature toughness of asphalt, a hydrogenation catalyst is also added in the step 1, and the hydrogenation catalyst is an aluminum oxide hydrogenation catalyst loaded with platinum.

[0021] In the above-mentioned method for preparing asphalt warm mix agent capable of improving low temperature toughness of asphalt, the mixed solvent of ketones and benzenes in step 2 is a mixed solvent of equal volumes of acetone and toluene, and the added amount of the mixed solvent is 5%-10% of the mass of hydrogenated product a.

[0022] In the above-mentioned method for preparing an asphalt warm mix agent that can improve the low-temperature toughness of asphalt, the crystallization step in the step 2 is: cooling at a rate of 3-5°C / h, when the temperature is cooled to 1-3°C higher than the freezing point of the hydrogenated product a, cooling at a rate of 0.5°C / h, when the temperature is cooled to 1-2°C lower than the freezing point of the hydrogenated product a, maintaining a constant temperature for 6-8h, and then heating at a rate of 1-2°C / h to 25-28°C, and then heating at a rate of 0.5°C / h to 30°C, and maintaining a constant temperature for 6-8h.

[0023] During the crystallization process, a common inert gas, such as helium, can be used to apply a certain pressure in the space above the crystallizer, which can further reduce the impurity content in the obtained primary product b.

[0024] In the above-mentioned method for preparing an asphalt warm mix agent that can improve the low-temperature toughness of asphalt, the evaporation temperature of the scraping evaporation in step three is 150-200°C, the pressure is 100-500Pa, the scraping speed is 100-300rpm, the condenser temperature of the scraping evaporator is 70-80°C, and the cold well temperature is 0-40°C.

[0025] In the above-mentioned method for preparing an asphalt warm mix agent that can improve the low-temperature toughness of asphalt, the step of reduced pressure distillation in step 4 is: after heating and melting the intermediate product 1, perform reduced pressure distillation, the temperature of the reduced pressure distillation is 200-240°C, and the pressure is 10-50Pa, to obtain heavy phase component 1 and light phase component 1, discard the light phase component 1 and collect the heavy phase component 1; perform reduced pressure distillation on the heavy phase component 1, the temperature of the reduced pressure distillation is 240-290°C, and the pressure is 5-50Pa, to obtain heavy phase component 2 and light phase component 2, discard the light phase component 2 and collect the heavy phase component 2; perform reduced pressure distillation on the heavy phase component 2, the temperature of the reduced pressure distillation is 290-320°C, and the pressure is 5-50Pa, wait until no bubbles are generated in the liquid phase, increase the distillation temperature to 320-350°C, obtain heavy phase component 3 and light phase component 3, discard the heavy phase component 3 and collect the light phase component 3, and obtain the intermediate product d.

[0026] In the above-mentioned method for preparing an asphalt warm mix agent capable of improving the low-temperature toughness of asphalt, the temperature of the catalytic hydrogenation in step 5 is 250-350° C., the pressure is 0.5-10 MPa, and the catalyst is palladium carbon.

[0027] In the above-mentioned method for preparing asphalt warm mix agent capable of improving low-temperature toughness of asphalt, the heating temperature in step six is ​​140-180°C, the pressurization pressure is 0.5-5Mpa, the initiator is benzoyl peroxide, and the addition amount is 0.5%-10% of the mass of the intermediate product e.

[0028] In the above-mentioned method for preparing a warm mix asphalt agent capable of improving the low-temperature toughness of asphalt, the mass of the intermediate product g added in step eight is 1%-30% of the mass of the intermediate product e added.

[0029] Compared with the prior art, the advantages of the present invention are:

[0030] The present invention further induces oxidation of the intermediate product e, reacts under alkaline conditions to obtain the intermediate product g, and compounding the intermediate product e and the intermediate product g to obtain a warm mix agent, so that the final warm mix agent contains polar bonds such as some lipids, thereby avoiding the problem of increased brittleness of asphalt at low temperatures due to the addition of the warm mix agent, and can even improve the low-temperature brittleness of asphalt to a certain extent, increase toughness, and enhance low-temperature performance. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with specific implementation methods.

[0032] Example 1

[0033] This embodiment provides a method for preparing an asphalt warm mix agent that can improve the low-temperature toughness of asphalt, comprising the following steps:

[0034] Step 1: Add Fischer-Tropsch wax and a hydrogenation catalyst into a hydrogenation reactor, heat and pressurize, and introduce hydrogen, the heating temperature is 400°C, the pressurization pressure is 10 MPa, the hydrogen-oil volume ratio is 800, and the hydrogenation catalyst is an aluminum oxide hydrogenation catalyst loaded with platinum, and after the reaction is completed, a hydrogenation product a is obtained;

[0035] Step 2: After the hydrogenation product a is melted, a mixed solvent of ketones and benzene is added, wherein the mixed solvent of ketones and benzene is a mixed solvent of equal volumes of acetone and toluene, and the amount of the mixed solvent added is 10% of the mass of the hydrogenation product a. After mixing evenly, the mixture is transferred to a crystallizer for crystallization to obtain a primary product b;

[0036] Step 3: After the primary product b is heated and melted, it is evaporated by a scraped film evaporator. The evaporation temperature of the scraped film evaporator is 200°C, the pressure is 500Pa, the scraped film speed is 300rpm, the condenser temperature of the scraped film evaporator is 80°C, the cold well temperature is 40°C, and the intermediate product c is obtained after condensation;

[0037] Step 4: distill the intermediate product c under reduced pressure to obtain the intermediate product d;

[0038] Step 5: catalytically hydrogenate the intermediate product d at a temperature of 350° C. and a pressure of 10 MPa using palladium carbon as the catalyst to obtain the intermediate product e;

[0039] Step 6: Mix the intermediate product e with the initiator, and react with oxygen under heating and pressurizing conditions, the heating temperature is 180° C., the pressurizing pressure is 5 MPa, the initiator is benzoyl peroxide, and the added amount is 10% of the mass of the intermediate product e. After the reaction is completed, vacuum extraction is performed under the protection of a nitrogen atmosphere to obtain an intermediate product f;

[0040] Step 7: Mix the intermediate product f with ammonia water for reaction, and maintain the pH value at about 8 during the reaction to obtain the intermediate product g;

[0041] Step 8: melt and mix the intermediate product g and the intermediate product e uniformly, with the mass of the intermediate product g added being 30% of the mass of the intermediate product e added, and granulate to obtain a warm mix agent product.

[0042] Among them, the crystallization step in step 2 is: cooling at a rate of 5°C / h until it is 3°C higher than the freezing point of the hydrogenated product a, cooling at a rate of 0.5°C / h until it is 2°C lower than the freezing point of the hydrogenated product a, maintaining a constant temperature for 8 hours, then heating at a rate of 2°C / h until it is 28°C, then heating at a rate of 0.5°C / h until it is 30°C, and maintaining the constant temperature for 8 hours.

[0043] The step of reduced pressure distillation in step 4 is as follows: after heating and melting the intermediate product 1, performing reduced pressure distillation at a temperature of 240° C. and a pressure of 50 Pa to obtain a heavy phase component 1 and a light phase component 1, discarding the light phase component 1 and collecting the heavy phase component 1; performing reduced pressure distillation on the heavy phase component 1 at a temperature of 290° C. and a pressure of 50 Pa to obtain a heavy phase component 2 and a light phase component 2, discarding the light phase component 2 and collecting the heavy phase component 2; performing reduced pressure distillation on the heavy phase component 2 at a temperature of 320° C. and a pressure of 50 Pa, and when no bubbles are generated in the liquid phase, raising the distillation temperature to 350° C. to obtain a heavy phase component 3 and a light phase component 3, discarding the heavy phase component 3 and collecting the light phase component 3, and obtaining an intermediate product d.

[0044] Example 2

[0045] This embodiment provides a method for preparing an asphalt warm mix agent that can improve the low-temperature toughness of asphalt, comprising the following steps:

[0046] Step 1: Add Fischer-Tropsch wax and hydrogenation catalyst into a hydrogenation reactor, heat and pressurize, and introduce hydrogen, the heating temperature is 300°C, the pressurization pressure is 0.5 MPa, the hydrogen-oil volume ratio is 50, the hydrogenation catalyst is a platinum-loaded aluminum oxide hydrogenation catalyst, and after the reaction is completed, a hydrogenation product a is obtained;

[0047] Step 2: After the hydrogenation product a is melted, a mixed solvent of ketones and benzene is added, wherein the mixed solvent of ketones and benzene is a mixed solvent of equal volumes of acetone and toluene, and the amount of the mixed solvent added is 5% of the mass of the hydrogenation product a. After mixing evenly, the mixture is transferred to a crystallizer for crystallization to obtain a primary product b;

[0048] Step 3: After the primary product b is heated and melted, it is evaporated by a scraped film evaporator, the evaporation temperature of the scraped film evaporator is 150°C, the pressure is 100Pa, the scraped film speed is 100rpm, the condenser temperature of the scraped film evaporator is 70°C, the cold well temperature is 0°C, and the intermediate product c is obtained after condensation;

[0049] Step 4: distill the intermediate product c under reduced pressure to obtain the intermediate product d;

[0050] Step 5: catalytically hydrogenate the intermediate product d at a temperature of 250° C. and a pressure of 0.5 MPa using palladium carbon as the catalyst to obtain the intermediate product e;

[0051] Step 6: Mix the intermediate product e with the initiator, and react with oxygen under heating and pressurizing conditions, the heating temperature is 140° C., the pressurizing pressure is 0.5 MPa, the initiator is benzoyl peroxide, and the added amount is 0.5% of the mass of the intermediate product e. After the reaction is completed, vacuum extraction is performed under the protection of a nitrogen atmosphere to obtain an intermediate product f;

[0052] Step 7: Mix the intermediate product f with ammonia water for reaction, and maintain the pH value at about 8 during the reaction to obtain the intermediate product g;

[0053] Step 8: melt and mix the intermediate product g and the intermediate product e uniformly, with the mass of the intermediate product g added being 1% of the mass of the intermediate product e added, and granulate to obtain a warm mix agent product.

[0054] Among them, the crystallization step in step 2 is: cooling at a rate of 3°C / h, cooling to 1°C higher than the freezing point of the hydrogenated product a, cooling at a rate of 0.5°C / h, cooling to 1°C lower than the freezing point of the hydrogenated product a, maintaining a constant temperature for 6 hours, then heating at a rate of 1°C / h to 25°C, then heating at a rate of 0.5°C / h to 30°C, and maintaining the temperature for 6 hours.

[0055] The step of reduced pressure distillation in step 4 is as follows: after heating and melting the intermediate product 1, performing reduced pressure distillation at a temperature of 200° C. and a pressure of 10 Pa to obtain a heavy phase component 1 and a light phase component 1, discarding the light phase component 1 and collecting the heavy phase component 1; performing reduced pressure distillation on the heavy phase component 1 at a temperature of 240° C. and a pressure of 5 Pa to obtain a heavy phase component 2 and a light phase component 2, discarding the light phase component 2 and collecting the heavy phase component 2; performing reduced pressure distillation on the heavy phase component 2 at a temperature of 290° C. and a pressure of 5 Pa, and when no bubbles are generated in the liquid phase, raising the distillation temperature to 320° C. to obtain a heavy phase component 3 and a light phase component 3, discarding the heavy phase component 3 and collecting the light phase component 3, and obtaining an intermediate product d.

[0056] Example 3

[0057] This embodiment provides a method for preparing an asphalt warm mix agent that can improve the low-temperature toughness of asphalt, comprising the following steps:

[0058] Step 1: Add Fischer-Tropsch wax and a hydrogenation catalyst into a hydrogenation reactor, heat and pressurize, and introduce hydrogen, the heating temperature is 350°C, the pressurization pressure is 5 MPa, the hydrogen-oil volume ratio is 400, and the hydrogenation catalyst is an aluminum oxide hydrogenation catalyst loaded with platinum, and after the reaction is completed, a hydrogenation product a is obtained;

[0059] Step 2: After the hydrogenation product a is melted, a mixed solvent of ketones and benzene is added, wherein the mixed solvent of ketones and benzene is a mixed solvent of equal volumes of acetone and toluene, and the amount of the mixed solvent added is 8% of the mass of the hydrogenation product a. After mixing evenly, the mixture is transferred to a crystallizer for crystallization to obtain a primary product b;

[0060] Step 3: After the primary product b is heated and melted, it is evaporated by a scraped film evaporator, the evaporation temperature of the scraped film evaporator is 175°C, the pressure is 300Pa, the scraped film speed is 200rpm, the condenser temperature of the scraped film evaporator is 75°C, the cold well temperature is 20°C, and the intermediate product c is obtained after condensation;

[0061] Step 4: distill the intermediate product c under reduced pressure to obtain the intermediate product d;

[0062] Step 5: catalytically hydrogenate the intermediate product d at a temperature of 300° C. and a pressure of 5 MPa using palladium carbon as the catalyst to obtain the intermediate product e;

[0063] Step 6: Mix the intermediate product e with the initiator, and react with oxygen under heating and pressurizing conditions, the heating temperature is 160° C., the pressurizing pressure is 2.5 MPa, the initiator is benzoyl peroxide, and the added amount is 5% of the mass of the intermediate product e. After the reaction is completed, vacuum extraction is performed under the protection of a nitrogen atmosphere to obtain an intermediate product f;

[0064] Step 7: Mix the intermediate product f with ammonia water for reaction, and maintain the pH value at about 8 during the reaction to obtain the intermediate product g;

[0065] Step 8: melt and mix the intermediate product g and the intermediate product e uniformly, with the mass of the intermediate product g added being 13% of the mass of the intermediate product e added, and granulate to obtain a warm mix agent product.

[0066] Among them, the crystallization step in step 2 is: cooling at a rate of 4°C / h until it is 2°C higher than the freezing point of the hydrogenated product a, cooling at a rate of 0.5°C / h until it is 1.5°C lower than the freezing point of the hydrogenated product a, maintaining a constant temperature for 7 hours, then heating at a rate of 1.5°C / h until it reaches 26°C, then heating at a rate of 0.5°C / h until it reaches 30°C, and maintaining the temperature for 7 hours.

[0067] The step of reduced pressure distillation in step 4 is as follows: after heating and melting the intermediate product 1, performing reduced pressure distillation at a temperature of 220° C. and a pressure of 25 Pa to obtain a heavy phase component 1 and a light phase component 1, discarding the light phase component 1 and collecting the heavy phase component 1; performing reduced pressure distillation on the heavy phase component 1 at a temperature of 280° C. and a pressure of 20 Pa to obtain a heavy phase component 2 and a light phase component 2, discarding the light phase component 2 and collecting the heavy phase component 2; performing reduced pressure distillation on the heavy phase component 2 at a temperature of 300° C. and a pressure of 10 Pa, and when no bubbles are generated in the liquid phase, raising the distillation temperature to 330° C. to obtain a heavy phase component 3 and a light phase component 3, discarding the heavy phase component 3 and collecting the light phase component 3, and obtaining an intermediate product d.

[0068] Comparative Example 1

[0069] This comparative example provides a method for preparing a warm mix asphalt agent, comprising the following steps:

[0070] Step 1: Add Fischer-Tropsch wax and a hydrogenation catalyst into a hydrogenation reactor, heat and pressurize, and introduce hydrogen, the heating temperature is 350°C, the pressurization pressure is 5 MPa, the hydrogen-oil volume ratio is 400, and the hydrogenation catalyst is an aluminum oxide hydrogenation catalyst loaded with platinum, and after the reaction is completed, a hydrogenation product a is obtained;

[0071] Step 2: After the hydrogenation product a is melted, a mixed solvent of ketones and benzene is added, wherein the mixed solvent of ketones and benzene is a mixed solvent of equal volumes of acetone and toluene, and the amount of the mixed solvent added is 8% of the mass of the hydrogenation product a. After mixing evenly, the mixture is transferred to a crystallizer for crystallization to obtain a primary product b;

[0072] Step 3: After the primary product b is heated and melted, it is evaporated by a scraped film evaporator, the evaporation temperature of the scraped film evaporator is 175°C, the pressure is 300Pa, the scraped film speed is 200rpm, the condenser temperature of the scraped film evaporator is 75°C, the cold well temperature is 20°C, and the intermediate product c is obtained after condensation;

[0073] Step 4: distill the intermediate product c under reduced pressure to obtain the intermediate product d;

[0074] Step 5: subjecting the intermediate product d to a catalytic hydrogenation reaction at a temperature of 300° C. and a pressure of 5 MPa, using palladium carbon as the catalyst, to obtain an intermediate product e, which is then granulated to obtain a warm mix agent product.

[0075] Among them, the crystallization step in step 2 is: cooling at a rate of 4°C / h until it is 2°C higher than the freezing point of the hydrogenated product a, cooling at a rate of 0.5°C / h until it is 1.5°C lower than the freezing point of the hydrogenated product a, maintaining a constant temperature for 7 hours, then heating at a rate of 1.5°C / h until it reaches 26°C, then heating at a rate of 0.5°C / h until it reaches 30°C, and maintaining the temperature for 7 hours.

[0076] The step of reduced pressure distillation in step 4 is as follows: after heating and melting the intermediate product 1, performing reduced pressure distillation at a temperature of 220° C. and a pressure of 25 Pa to obtain a heavy phase component 1 and a light phase component 1, discarding the light phase component 1 and collecting the heavy phase component 1; performing reduced pressure distillation on the heavy phase component 1 at a temperature of 280° C. and a pressure of 20 Pa to obtain a heavy phase component 2 and a light phase component 2, discarding the light phase component 2 and collecting the heavy phase component 2; performing reduced pressure distillation on the heavy phase component 2 at a temperature of 300° C. and a pressure of 10 Pa, and when no bubbles are generated in the liquid phase, raising the distillation temperature to 330° C. to obtain a heavy phase component 3 and a light phase component 3, discarding the heavy phase component 3 and collecting the light phase component 3, and obtaining an intermediate product d.

[0077] Application Example 1

[0078] Take three portions of equal mass from the same batch of asphalt, add the warm mix agent product prepared in Example 3 and the warm mix agent product prepared in Comparative Example 1 to two portions of the asphalt respectively, the amount of asphalt warm mix agent added is 2% of the mass of the asphalt, and after stirring, obtain Asphalt 1 and Asphalt 2 respectively. The portion without the addition of the warm mix agent is numbered asphalt 3.

[0079] The relevant performance data of asphalt 1-3 were measured according to the relevant measurement methods recorded in JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering". The results are shown in the following table:

[0080] Experimental subjects -10℃ bending test, maximum bending strain (με) Asphalt 1 3174 Asphalt 2 3074 Asphalt 3 3143

[0081] Result analysis: By comparing the relevant properties of asphalts 1-3, it can be seen that the asphalt warm mix agent provided by the present invention can improve the toughness of asphalt under low temperature conditions to a certain extent, achieving the expected purpose of the present invention.

[0082] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A method for preparing a warm mix asphalt agent capable of improving the low temperature toughness of asphalt, characterized in that: The following steps are involved: Step 1: adding Fischer-Tropsch wax to a hydrogenation reactor, heating and pressurizing, and introducing hydrogen, and obtaining a hydrogenation product a after the reaction is completed; Step 2: After the hydrogenation product a is melted, a mixed solvent of ketones and benzene is added, and after mixing evenly, the mixture is transferred to a crystallizer for crystallization to obtain a primary product b; Step 3: After heating and melting the primary product b, the product is evaporated by a wiped film evaporator to obtain an intermediate product c after condensation; Step 4: distill the intermediate product c under reduced pressure to obtain the intermediate product d; Step 5: performing a catalytic hydrogenation reaction on the intermediate product d to obtain an intermediate product e; Step 6: Mix the intermediate product e with the initiator, react with oxygen under heating and pressurization conditions, and after the reaction is completed, perform vacuum extraction under the protection of a nitrogen atmosphere to obtain the intermediate product f; Step 7: Mix the intermediate product f with a weakly alkaline substance to react to obtain an intermediate product g; Step 8: melt and mix the intermediate product g and the intermediate product e uniformly, and granulate to obtain a warm mix product.

2. The method for preparing a warm mix asphalt agent capable of improving the low temperature toughness of asphalt according to claim 1, characterized in that: The heating temperature in the step 1 is 300-400° C., the pressurization pressure is 0.5-10 MPa, and the hydrogen-to-oil volume ratio is 50-800.

3. The method for preparing a warm mix asphalt agent capable of improving the low temperature toughness of asphalt according to claim 1, characterized in that: A hydrogenation catalyst is also added in the step 1, and the hydrogenation catalyst is an aluminum oxide hydrogenation catalyst loaded with platinum.

4. The method for preparing a warm mix asphalt agent capable of improving the low temperature toughness of asphalt according to claim 1, characterized in that: In the step 2, the mixed solvent of ketones and benzenes is a mixed solvent of equal volumes of acetone and toluene, and the added amount of the mixed solvent is 5%-10% of the mass of the hydrogenation product a.

5. The method for preparing a warm mix asphalt agent capable of improving the low temperature toughness of asphalt according to claim 1, characterized in that: The crystallization step in the step 2 is as follows: cooling at a rate of 3-5°C / h until the temperature is 1-3°C higher than the freezing point of the hydrogenated product a, cooling at a rate of 0.5°C / h until the temperature is 1-2°C lower than the freezing point of the hydrogenated product a, maintaining a constant temperature for 6-8h, and then heating at a rate of 1-2°C / h until the temperature reaches 25-28°C, and then heating at a rate of 0.5°C / h until the temperature reaches 30°C, and maintaining the constant temperature for 6-8h.

6. The method for preparing a warm mix asphalt agent capable of improving the low temperature toughness of asphalt according to claim 1, characterized in that: In the step three, the evaporation temperature of the scraped film evaporation is 150-200°C, the pressure is 100-500Pa, the scraped film speed is 100-300rpm, the condenser temperature of the scraped film evaporator is 70-80°C, and the cold well temperature is 0-40°C.

7. The method for preparing a warm mix asphalt agent capable of improving the low temperature toughness of asphalt according to claim 1, characterized in that: The step of reduced pressure distillation in step 4 is as follows: after heating and melting the intermediate product 1, performing reduced pressure distillation, the temperature of the reduced pressure distillation is 200-240°C, and the pressure is 10-50Pa, to obtain heavy phase component 1 and light phase component 1, discard the light phase component 1 and collect the heavy phase component 1; performing reduced pressure distillation on the heavy phase component 1, the temperature of the reduced pressure distillation is 240-290°C, and the pressure is 5-50Pa, to obtain heavy phase component 2 and light phase component 2, discard the light phase component 2 and collect the heavy phase component 2; performing reduced pressure distillation on the heavy phase component 2, the temperature of the reduced pressure distillation is 290-320°C, and the pressure is 5-50Pa, until no bubbles are generated in the liquid phase, raising the distillation temperature to 320-350°C, to obtain heavy phase component 3 and light phase component 3, discard the heavy phase component 3 and collect the light phase component 3, and obtain the intermediate product d.

8. The method for preparing a warm mix asphalt agent capable of improving the low temperature toughness of asphalt according to claim 1, characterized in that: The temperature of the catalytic hydrogenation in step 5 is 250-350° C., the pressure is 0.5-10 MPa, and the catalyst is palladium carbon.

9. The method for preparing a warm mix asphalt agent capable of improving the low temperature toughness of asphalt according to claim 1, characterized in that: The heating temperature in step six is ​​140-180° C., the pressurizing pressure is 0.5-5 MPa, the initiator is benzoyl peroxide, and the added amount is 0.5%-10% of the mass of the intermediate product e.

10. The method for preparing a warm mix asphalt agent capable of improving the low temperature toughness of asphalt according to claim 1, characterized in that: The mass of the intermediate product g added in step eight is 1%-30% of the mass of the intermediate product e added.