CN107523072B - Warm-mixed sulfur asphalt, mixture containing warm-mixed sulfur asphalt and preparation method of warm-mixed sulfur asphalt - Google Patents

Abstract

The invention discloses warm-mixed sulfur asphalt. The product comprises warm mixing agent, base asphalt and sulfur. The warm mixing agent is prepared by taking polyethylene wax as a raw material through a sweating process. In the sweating process, organic substances with oil solubility and capable of being decomposed to generate gas are added into a byproduct polyethylene wax raw material in advance, and the gas generated after the heating is utilized to form micro bubbles in a wax layer, so that the liquid components can be discharged quickly, and the low-molecular-weight components in the raw material can be removed; meanwhile, in the sweating process, the liquid component is carried by the airflow through the wax layer so as to separate the solid component and the liquid component forcibly, and the low molecular weight component in the raw material is removed more effectively. The warm-mixed sulfur asphalt provided by the invention reduces the preparation temperature and the use temperature of the sulfur asphalt, reduces the generation amount of harmful gas, and simultaneously improves the high-temperature stability of the asphalt pavement.

Description

Warm-mixed sulfur asphalt, mixture containing warm-mixed sulfur asphalt and preparation method of warm-mixed sulfur asphalt

Technical Field

The invention relates to warm-mixed asphalt, in particular to warm-mixed sulfur asphalt, a mixture containing the warm-mixed sulfur asphalt and a preparation method of the warm-mixed sulfur asphalt, and belongs to the fields of petroleum industry and basic material chemistry.

Background

Due to the increasing number of vehicles and the overloading of transportation in China, the phenomena of rutting, cuddling and the like on asphalt pavements are becoming more and more serious, and the method is particularly prominent in hot areas in the south of China. The phenomenon becomes one of the main damage forms of the asphalt road in China at present, and the driving safety and the service life of the asphalt road surface are seriously influenced.

The low 60 ℃ viscosity of bitumen is also one of the causes of this failure phenomenon, as is the binder itself. The viscosity of the asphalt at 60 ℃ is used as one of indexes for representing the high-temperature stability of the asphalt, and the anti-flow performance of the asphalt when the road surface temperature of the asphalt pavement reaches the high temperature of 60 ℃ in summer can be well simulated. The 'technical requirement for road petroleum asphalt' in 'technical Specification for road asphalt pavement construction' issued by Ministry of transportation formally lists the dynamic viscosity at 60 ℃ of road asphalt as a technical index of road asphalt products. Therefore, how to effectively improve the dynamic viscosity of the road petroleum asphalt at 60 ℃ is very important.

In order to improve the dynamic viscosity of the asphalt at 60 ℃ and improve the high-temperature stability of the asphalt, Japanese patent application laid-open No. 8-12977, CN1289818A, CN1076386C and the like adopt an oxidation or semi-oxidation method, and air is introduced into the asphalt at a certain temperature to cause the asphalt to generate reactions such as oxidation, polymerization and the like, thereby changing the composition structure of the asphalt and achieving the purpose of improving the viscosity of the asphalt. However, as the service life of the asphalt pavement increases, the asphalt component in the asphalt pavement is aged by light, the property is deteriorated, and the road quality is deteriorated. The asphalt produced by the oxidation method is actually a process of pre-aging asphalt components before being applied to roads, the service life of the asphalt on the road surface is shortened while the use performance of the asphalt is improved, and the asphalt produced by the oxidation method consumes much energy and generates more waste gas, thereby causing adverse effects on human health and environment.

CN97116936.5 provides a method for producing heavy traffic road asphalt with higher viscosity at 60 ℃. The asphalt is prepared by carrying out propane deoiling treatment on the Aman straight-run asphalt and then carrying out semi-oxidation treatment, namely, the solvent extraction and semi-oxidation method are combined to prepare the high-viscosity asphalt, but the method has complex process, a large amount of solvent is needed in the extraction process, the operation pressure is higher, and the solvent is also easy to cause fire; the oxidation process also produces a large amount of exhaust gas, causing air pollution.

CN201210561929.2 discloses an asphalt paint, comprising: potassium chloride, m-nitrophenol, anthraquinone, sodium dodecyl benzene sulfonate, tetraethyl ammonium chloride, hexadecyl tributyl phosphorus bromide, 4-bromo-1-butanol, diethylaminoethanol caproate and praseodymium trifluoroacetylacetone. Anthraquinone, although used in this patent, is intended to produce asphalt paint, rather than to improve the 60 ℃ viscosity of road asphalt.

The invention discloses CN201110441529.3 a high viscosity modified asphalt, which is composed of common A-grade asphalt, thermoplastic elastomer, high styrene, compatibilizer and stabilizer, and the modified asphalt with higher viscosity at 60 ℃ is obtained through the process steps of swelling, shearing or grinding, development and the like. However, the method has strict requirements on equipment, high material and equipment investment, can greatly increase the production cost, has a problem in the storage stability of the product, and is easy to generate a layering segregation phenomenon after long-time storage.

Researches show that the sulfur asphalt is prepared by adding sulfur into asphalt, and the highway paved by the sulfur asphalt mixture has obvious anti-rutting performance. However, the sulfur asphalt mixture releases a large amount of harmful gases such as hydrogen sulfide and sulfur dioxide during use, so that the application of the sulfur asphalt mixture is limited. How to develop the method can not only use the sulfur asphalt mixture to pave the road to improve the anti-rutting performance of the road, but also reduce the air pollution as much as possible, and becomes a new research subject. This requires combining the sulphur pitch with warm mix technology.

The warm mix asphalt mixture technology mainly has three modes: firstly, adopting emulsified asphalt with high content of evaporation residues to mix with stone materials at the temperature of 80-120 ℃, wherein the temperature of the emulsified asphalt is about 30-50 ℃ lower than that of hot-mixed asphalt; secondly, when the mixture is stirred, water (or water solution of a surfactant) and asphalt are added into the mixing tank at the same time, and the asphalt is foamed due to the existence of the water, so that the viscosity reduction effect is achieved. However, the two methods generate a large amount of water vapor, which easily causes equipment corrosion, and often causes stone powder agglomeration to cause problems of blockage of dust removal equipment and the like, thereby bringing inconvenience to production. The third method is to add the warm-mix agent to the asphalt in advance, and then adopt the same production mode as the common hot-mix asphalt mixture, so that the operation is convenient and the method is easily accepted by production units. According to the method, the warm-mixing agent is added into the asphalt in advance, so that the high-temperature viscosity of the asphalt is reduced, the viscosity-temperature curve of the asphalt is changed, the mixing temperature of the asphalt and stone is reduced, and the warm-mixing effect is achieved. However, the warm-mixing agent used at present can reduce the high-temperature viscosity of the asphalt, and usually also cause the viscosity of the asphalt at 60 ℃ to be reduced, so that the high-temperature stability of the asphalt mixture is lost.

During the production of polyethylene, small amounts of oligomers, i.e. low molecular weight polyethylene or polyethylene wax, are produced. The polyethylene wax has wide molecular weight distribution and contains a large amount of low molecular components, and when the polyethylene wax is directly used as an asphalt warm-mixing agent, although the polyethylene wax can play a warm-mixing effect, the polyethylene wax is easy to cause damage phenomena such as road congestion and rutting. How to effectively remove the low molecular components in the asphalt mixture to make the asphalt mixture more suitable for being used as an asphalt warm-mixing agent is the subject of research in the industry.

CN200880116167.7 (asphalt modifier for "warm mix" including tackifier) prepared an asphalt warm mix using a surfactant component, a wax component, and a resin component. The warm mixing effect is achieved by utilizing the lubricating effect of the surfactant component; the wax component (vegetable wax, animal wax, mineral wax, amide wax, oxidized wax, etc.) and the resin component act as a tackifying effect to compensate for the loss in viscosity of the asphalt due to the surfactant component described above. The patent uses too many components, easily reduces the viscosity of the asphalt at 60 ℃, influences the high-temperature stability of the asphalt and reduces the adhesion of the asphalt and stone materials. Although the resin component such as rosin, phenol resin and the like is added to compensate for the loss of the viscosity of the asphalt due to the above surfactant component, the compatibility of the resin component with the asphalt is poor and the asphalt is likely to be delaminated when stored for a long period of time.

CN201010558295.6 (a warm mix modifier for asphalt mixture and a preparation method thereof) utilizes F-T wax, a plasticizer, polybasic acid, synthetic resin and a polyester compound to prepare the warm mix modifier, wherein the F-T wax is used for reducing the viscosity of asphalt, the carbon number of the F-T wax is between 40 and 80 (preferably between 45 and 70), the proportion of normal alkane is more than 80 percent (preferably between 85 and 95 percent), the acid value is 0 to 1 (preferably between 0 and 0.5), and the melting point is between 55 and 120 ℃ (preferably between 70 and 110 ℃). The patent does not describe the source of the F-T wax feed and from the examples the penetration (25 ℃ C.) of the F-T wax feed is only 53.2 (10 ℃ C.)^-1mm) the fischer-tropsch wax feed contains more low molecular weight components, which reduce the viscosity of the bitumen product at 60 ℃.

In the production process of wax products, the separation and processing means commonly used include distillation, solvent separation, sweating separation and the like. The warm mixing agent can be produced by referring to a wax sweating process.

The wax sweating separation method is to separate and purify wax by utilizing the property that various components in the wax have different melting points. The melting points of the various components of the wax will vary depending on their molecular weights and structures. When the normal paraffin is the same as the normal paraffin, the melting point of the normal paraffin with larger molecular weight is higher, and the melting point of the normal paraffin with smaller molecular weight is lower; the same molecular weight, isoparaffins and naphthenes have lower melting points than normal paraffins, and the higher the degree of isomerization, the lower the melting point.

The common sweating process mainly comprises the following steps: (1) preparation work: filling water (filling the space under the dish plate of the sweating device with water), and then loading the materials (loading the materials into the sweating device when the materials are heated to be liquid above the melting point); (2) and (3) crystallization: and slowly cooling the raw materials to 10-20 ℃ below the melting point of the raw materials at a cooling rate of not more than 4 ℃/h. In the cooling process, the components are crystallized sequentially from high to low according to the melting points to form solids; (3) sweating: when the temperature of the wax layer reaches the preset temperature reduction termination temperature, draining the padding water; the material is then slowly heated to a predetermined sweating termination temperature. During sweating, the components are sequentially melted into liquid state according to the sequence of melting point from low to high and flow out (under wax), and finally the wax layer residue (on wax) is the wax with high melting point and low oil content; (4) refining: collecting the crude product (raising the temperature continuously after the sweating process is finished to melt and take out the wax to obtain the crude product), performing clay refining (heating the crude product to a preset temperature after melting, adding clay, stirring at a constant temperature for a preset time, and filtering), and then molding and packaging to obtain the target product.

In the conventional sweating separation method, the solid component (wax with a higher melting point) and the liquid component (oil and wax with a lower melting point) are in two phases of solid and liquid respectively during warming and sweating, but are difficult to be completely separated. In order to meet the oil content of the final product, methods of prolonging the sweating time and raising the sweating termination temperature are generally used, but this results in long production cycles and a decrease in product yield.

The common sweating separation process can produce soap wax and low-melting-point paraffin with coarse flaky crystal structures at the melting point of 40-60 ℃ in a solid state, and is not suitable for producing wax products with the melting point of more than 70 ℃. Tests show that when a wax product with the melting point of about 70 ℃ is produced by a common sweating process, the carbon distribution width and the oil content on the wax at the sweating later stage are irrelevant to the yield, namely the carbon distribution width and the oil content on the wax are not reduced along with the reduction of the yield, so that no report of producing the wax product with the melting point of about 70 ℃ by the sweating process is seen so far.

For years, the sweating method is developed in the aspects of production equipment and processes, such as CN89214332 (vertical square multi-section partition sweating tank), CN94223980.6 (dish type sweating device), CN98233254.8 (paraffin sweating tank), CN200920033500.X (novel paraffin sweating tank), CN201210508905.0 (high-efficiency paraffin sweating device), CN201320127680.4 (tubular paraffin deoiling device) and the like, and improvement is made on the sweating equipment; CN91206202 (a high-efficiency paraffin wax sweating pot) is improved in sweating process, but these improvements still cannot produce wax products with melting point above 70 ℃.

The sweating separation process is the only solvent-free separation method for producing petroleum wax products on an industrial scale at present, and the demand of producing the asphalt warm-mixing agent product which does not influence the high-temperature use performance of asphalt while reducing the high-temperature viscosity of the asphalt by adopting the sweating process is more urgent at present when green, low-carbon, environmental-friendly and energy-saving production is promoted.

In the existing preparation process of warm mix asphalt, the viscosity or the ductility of the asphalt at 60 ℃ is usually reduced while the mixing temperature of the asphalt mixture is reduced, so that the high-temperature stability or the low-temperature cracking resistance of the asphalt mixture is influenced. How to adopt a special warm mixing agent, the high and low temperature service performance of the asphalt is not influenced while the mixing and forming temperature of the asphalt is reduced, and the problem becomes a hot spot problem in the current development of warm mixing asphalt.

In the natural gas processing and petroleum refining processes, sulfur is removed in order to produce clean fuel, so that a large amount of sulfur byproducts are generated, and the sulfur market presents an over-supply situation. How to effectively utilize the sulfur and solve the sale of the sulfur becomes a problem to be solved urgently for natural gas processing and oil refining enterprises. In addition, due to the increasing number of vehicles and the overloading of transportation in China, the phenomena of rutting, cuddling and the like on the asphalt pavement are becoming more and more serious, and the phenomena are particularly prominent in hot areas in the south of China. The phenomenon becomes one of the main damage forms of the asphalt road in China at present, and the driving safety and the service life of the asphalt road surface are seriously influenced. Research shows that the sulfur is added into the asphalt for paving the road, so that the application field of the sulfur can be expanded, the market of the sulfur can be expanded, and the anti-rutting performance of the asphalt pavement can be improved.

As early as 1900, people beganModification of asphalt with sulphur, but due to the rising price of sulphur at that time, and the release of H during the production of sulphur-modified asphalt mixes₂S and other sulfur-containing gases restrict the development of the technology for modifying the asphalt from sulfur. Later, with the development of polymer modified asphalt, sulfur has also been used in asphalt, mainly as a stabilizer for polymer modified asphalt to improve the storage stability of the product. However, the dosage of the sulfur in the polymer modified asphalt is only 0.01wt% -0.1 wt%, which is not enough to promote the application of the sulfur in the asphalt in large quantity. Therefore, how to use a large amount of sulfur in asphalt without causing air pollution is a contradiction to be solved.

CN 1690197 describes a method for preparing a sulfur modified asphalt mixture by adding a certain proportion of sulfur, carbon, a smoke inhibitor and a plasticizer into base asphalt.

CN103030984A describes a method for preparing sulfur modified asphalt by adding sulfur, gypsum whisker and smoke inhibitor into base asphalt.

CN102321373A introduces a preparation method of warm-mix sulfur asphalt, which specifically comprises the steps of mixing sulfur and a plasticizer for 1-24 hours to form a linear high molecular substance, and then adding the linear high molecular substance, a deodorant and an aroma enhancer into matrix asphalt at 130-160 ℃ to mix for at least 30 minutes to obtain warm-mix asphalt.

CN101443558B is prepared into polymer modified asphalt by using matrix asphalt, SBS and the like, then sulfur, diatomite and the like are added into the modified asphalt to prepare warm-mix asphalt, and fiber and the like are added during mixing of the mixture to prepare the warm-mix anti-skid and noise-reduction asphalt pavement material.

CN201110236016.9 introduces a preparation method of warm mix asphalt, which comprises the steps of mixing sulfur and a plasticizer for 1-24 hours to form a linear high molecular substance, adding the linear high molecular substance, a deodorant and an aroma enhancer into matrix asphalt at 130-160 ℃, and mixing for at least 30 minutes to obtain the warm mix asphalt. However, the preparation and use temperatures of the sulfur asphalt are high, toxic gases such as hydrogen sulfide and sulfur dioxide are released, the harm to the environment and the health of constructors is large, and although the emission of the toxic gases can be partially inhibited or the pungent odor of the toxic gases can be covered by adding a smoke inhibitor, a flavoring agent, a deodorant and the like, the problems of large odor and toxicity of the sulfur asphalt in the preparation and use processes cannot be fundamentally solved by the methods.

CN201510022090.9 discloses a warm-mix asphalt mixture and a preparation method thereof, wherein the warm-mix agent is prepared by using high-molecular alkane and aromatic oil as raw materials and adding halogen and a catalyst. Although the patent solves the problems to some extent, in the process of preparing the warm mixing agent, the reaction temperature of the intermediate is low, the catalyst is lacked, the reaction speed is slow, the activity of the intermediate is low, the reaction degree of the intermediate and aromatic oil is influenced, the reaction depth is not easy to control, the property of the obtained warm mixing agent is unstable, and the application effect in asphalt is influenced. In addition, the preparation process of the warm mixing agent is complex, and the problem of poor ageing resistance is also caused when the warm mixing agent is used in asphalt.

In the prior art, the use temperature is not effectively reduced in the process of preparing the sulfur asphalt, the preparation and use temperatures of the sulfur modified asphalt are higher, toxic gases such as hydrogen sulfide and sulfur dioxide are released, the harm to the environment and the health of constructors is larger, although smoke inhibitors, flavoring agents, odor removing agents and the like are added to partially inhibit the emission of the toxic gases or cover the pungent odor of the toxic gases, the methods cannot radically solve the problems of large odor and toxicity of the sulfur asphalt in the preparation and use processes.

Disclosure of Invention

In order to solve the problems that the sulfur asphalt in the prior art is high in use temperature and easy to cause environmental pollution and the like, the invention firstly provides warm-mixed sulfur asphalt. By adding the self-made warm mixing agent, the production and use temperature of the sulfur asphalt can be obviously reduced, the air pollution caused by the sulfur asphalt in production and use is reduced, and meanwhile, the thermal stability of the asphalt can be improved, and the anti-aging performance is improved. More sulfur can be added, the application of the sulfur in the asphalt is promoted, and the application range of the sulfur is expanded.

The technical purpose of the invention is realized by the following technical scheme:

the warm-mixed sulfur asphalt comprises the following components in parts by mass:

33-79.5 parts of matrix asphalt;

0.5-7 parts of warm mixing agent;

20-60 parts of sulfur;

the warm mixing agent is prepared by the following method:

(1) charging: heating and melting polyethylene wax serving as a byproduct of polyethylene, adding oil-soluble and decomposable organic substances for generating gas into the polyethylene wax, uniformly stirring, and then putting the mixture into a sweating device;

(2) and (3) crystallization: cooling the wax layer to a cooling termination temperature of 5-30 ℃ below the dropping melting point of the raw material at a speed of 2.0-4.0 ℃/h;

(3) temperature rise-constant temperature sweating: heating at the speed of 1.5-3.5 ℃/h, stopping sweating after the wax layer reaches the preset temperature and is kept at the constant temperature for a period of time, and forcing airflow to pass through the wax layer in the sweating process;

(4) discharging: discharging the remainder in the sweating device to obtain the asphalt warm-mixing agent.

Furthermore, in the warm-mixed sulfur asphalt composed of the above components in parts by mass, the addition amount of the warm-mixing agent is preferably 1 to 7 parts.

The oil-soluble decomposable substance in the step (1) comprises one or more of an organic azo compound, a sulfonyl hydrazide compound, an organic nitroso compound and an organic peroxide, and preferably one or more of an organic azo compound and an organic peroxide. The addition amount of the oil-soluble decomposable substance is 0.01-15.00% of the weight of the raw materials, and preferably 0.03-8.00%.

Wherein the organic azo compound is selected from the group consisting of Azobisisoheptonitrile (ABVN), Azobisisobutyronitrile (AIBN), and azobiscyclohexyl carbonitrile (ACCN); the sulfonyl hydrazide compound is selected from a group of substances consisting of benzenesulfonyl hydrazide, p-toluenesulfonyl hydrazide and 4, 4' -oxidized bis (benzenesulfonyl hydrazide); the organic nitroso compound is selected from dinitrosopentamethylenetetramine and/or N, N '-dimethyl N, N' -dinitrosophthalamide; the organic peroxide is selected from a group consisting of dibenzoyl peroxide (BPO), Lauroyl Peroxide (LPO), diacetyl peroxide, isopropyl peroxydicarbonate (IPP), dicyclohexyl peroxydicarbonate (DCPO) and the like.

In the invention, the cooling rate of the crystallization in the step (2) is preferably 2.5-3.5 ℃/h. The temperature reduction termination temperature is preferably 10-20 ℃ below the melting point of the raw material drops.

In the invention, the sweating device is preferably a sweating dish, and a pressurizing device is added above the wax layer and/or a vacuum device is added below the wax layer. When the warm mixing agent is prepared, in the sweating process in the step (3), the forced airflow passes through the wax layer by increasing the air pressure above the wax layer and/or reducing the air pressure below the wax layer, so that the pressure difference is formed between the upper part and the lower part of the wax layer. The pressure differential is generally between 0.1 and 5.0 atmospheres, preferably between 0.2 and 2.0 atmospheres, to force the air flow through the wax layer.

In the invention, the heating rate of the sweating process in the step (3) is preferably 2.0-3.0 ℃/h; the preset temperature for heating is-10 ℃ of the drop melting point of the target product to the drop melting point of the target product. After the wax layer reaches the preset temperature, a constant temperature stage is added to enable the solid component and the liquid component to be separated more fully, and the time of the constant temperature stage is 0-5.0 hours, preferably 0.1-5.0 hours, and more preferably 1.0-5.0 hours.

In the present invention, the temperature rising rate and the temperature lowering rate of the wax layer may be controlled by an air bath, a water bath, an oil bath, or other feasible methods, and preferably, a water bath or an oil bath is used. When the wax layer heating rate and the wax layer cooling rate are controlled by adopting a water bath or oil bath mode, a jacket can be added outside the sweating dish, the jacket is connected with a movable coil and a circulating system, and the jacket, the coil and the like can enable the wax layer heating/cooling process to be faster and the wax layer temperature to be more uniform; the circulating system has a program cooling/heating function, and substances such as water or heat-conducting oil and the like are added into the circulating system to serve as circulating media.

In the present invention, the forced air flow of step (3) through the wax layer can be performed at any stage of the sweating process, preferably at the initial stage of sweating.

In the invention, the forced airflow passing through the wax layer in the step (3) is realized by increasing the air pressure above the wax layer, for example, the pressure of 0.2-2.0 atmospheric pressure (gauge pressure) can be applied above the wax layer, and the normal pressure is kept below the wax layer.

In the present invention, the forced air flow of step (3) through the wax layer is achieved by reducing the air pressure below the wax layer, for example, the normal pressure can be maintained above the wax layer, and the pressure of-0.2 to-1.0 atmosphere (gauge pressure) can be maintained below the wax layer.

In the invention, the raw material polyethylene wax is produced by decoloring low polymer generated in the production process of polyethylene, and the dropping melting point of the low polymer polyethylene wax is generally 70-98 ℃.

Analysis shows that the polyethylene wax by-produced by polyethylene has low melt viscosity, which is beneficial for using the polyethylene wax as a warm-mix agent for asphalt, but the polyethylene wax by-produced by polyethylene is not suitable for being directly used as the warm-mix agent for asphalt because of the existence of a large amount of low-melting point components, which can reduce the viscosity of the asphalt product at 60 ℃ when used in the asphalt product.

The sweating method is to separate the components by utilizing the different melting points of the components. Studies on the sweating process have shown that the liquid component is gradually drained along the crystalline portion during sweating, similar to the case where the liquid flows in a capillary. However, for the high melting point wax with the melting point of about 70 ℃, the chemical composition of the raw materials is complex, so that the crystal structure is fine and compact during crystallization, and huge filtration resistance is formed for discharging liquid components, so that the solid components and the liquid components are difficult to completely separate in the ordinary sweating process which naturally separates by gravity only, and therefore, the ordinary sweating separation process cannot produce wax products with the melting point of above 70 ℃.

In order to prepare the asphalt warm-mixing agent, by means of the deep research on the composition of polyethylene wax which is a byproduct of polyethylene, the reason that the polyethylene wax contains a large amount of low-melting-point components and is not suitable for being directly used as the asphalt warm-mixing agent is taken as a reference for removing the low-melting-point components by a wax sweating method. Through the intensive research on the common sweating process, aiming at the reason that the solid component and the liquid component are difficult to separate, forced airflow is adopted to pass through a wax layer in the sweating process, and meanwhile, oil-soluble decomposable substances are preferably added after the raw materials are heated and melted, and a constant temperature stage is added in the sweating process, so that the measures effectively remove the low-melting-point component, and the product is suitable for being used as an asphalt warm mixing agent.

Aiming at the reason that the solid component and the liquid component are difficult to separate in the sweating process, the solid component and the liquid component are forced to be separated by adopting a method that the liquid component is carried out by air flow through a wax layer in the sweating process, so that the separation effect is enhanced and the separation speed is accelerated; meanwhile, oil-soluble decomposable substances are preferably added after the raw materials are heated and melted, and the substances can be decomposed to generate gas and have better solubility in the raw materials to be uniformly dispersed in the wax layer. The wax layer is in a softer solid state after the raw material is cooled to a temperature below the dropping point and the sweating process is terminated, the gas released by the slowly decomposed decomposable substance in the process can form uniformly dispersed micro-bubbles in the wax layer, and the space formed by the micro-bubbles is easy to form a plurality of fine channels in the wax layer in the sweating process, so that the liquid component in the sweating process can be discharged. Oil-soluble decomposable substances which decompose to form non-toxic and odorless gases such as nitrogen or carbon dioxide are preferred, and other substances which are low in molecular weight and which are discharged out of the wax layer along with the liquid components during sweating are formed. And then assisting with a constant temperature stage of a sweating process to more fully separate solid components from liquid components, and the like, so that the sweating process can prepare the asphalt warm-mixing agent without low-melting-point components.

The base asphalt can be selected from one or more of various crude oils and petroleum asphalt produced by different processes, such as straight-run asphalt, oxidized asphalt, solvent deoiled asphalt or blended asphalt.

The sulfur is produced in the petroleum or natural gas processing process, and can be in industrial grade or food grade; may be orthorhombic sulfur or monoclinic sulfur; the form can be flake, powder or granular.

It is still another object of the present invention to provide a warm-mix sulfur asphalt mixture, in which the aforementioned warm-mix sulfur asphalt is used.

The technical scheme is as follows: the warm-mixed sulfur asphalt mixture comprises the following components in parts by mass based on the total mass of the mixture: 4.0-6.0 parts of warm-mixed sulfur asphalt, 1.0-3.0 parts of mineral powder and 91.0-95.0 parts of aggregate;

further, the aggregate is selected from at least one of limestone, basalt, andesite or granite aggregate; the proportion of the aggregate is in accordance with any one of dense gradation AC-10, AC-13, AC-16 or AC-20.

The mineral powder is formed by grinding ores, wherein the proportion of particles with the particle size of less than 0.075mm is more than 70% by mass fraction.

The invention also provides a preparation method of the warm-mixed sulfur asphalt mixture, which comprises the following steps:

① preparation of warm-mix sulfur asphalt comprises heating matrix asphalt to 110-140 deg.C, stirring, adding warm-mix agent, adding sulfur, and stirring;

②, respectively heating the stirring kettle and the aggregate to 110-150 ℃, simultaneously adding the aggregate and the mineral powder into the stirring kettle, and stirring;

③ heating the warm-mixed sulfur asphalt to a molten state, adding into a stirring kettle, mixing with the aggregate and the mineral powder, and stirring to obtain the warm-mixed sulfur asphalt mixture.

Further, in the step ①, after the warm-mixing agent is added, stirring and reacting are carried out for 30-60 min, after the sulfur is added, stirring and reacting are carried out for 40-120 min.

Compared with the prior art, the warm-mixed sulfur asphalt mixture has the following advantages:

1. the warm mixing agent is a self-made warm mixing agent, a special sweating process is adopted, the separation effect of a liquid component and a solid component is enhanced, the separation speed is accelerated, the low-melting-point component in the prepared warm mixing agent is removed, the warm mixing effect on the asphalt is achieved, and the high-temperature stability and the high-temperature anti-rutting performance of the asphalt are considered.

2. The warm-mixed sulfur asphalt has low use temperature, saves energy, reduces the generation amount of harmful gas and is beneficial to environmental protection.

3. Before the sulfur is added into the warm-mixed sulfur asphalt, the warm-mixed asphalt is prepared by the warm-mixed agent and the asphalt, so that the melting temperature of the asphalt is reduced, and then the sulfur is added, so that the preparation temperature of the sulfur asphalt can be reduced, and the generation amount of harmful gas is reduced.

4. The production process of the warm-mixed sulfur asphalt is carried out in a closed container, and a vacuumizing system is additionally arranged on a reactor, so that harmful gases such as H generated in the production process can be removed₂And after S and the like are collected, the sodium hydroxide alkali solution is used for absorption to carry out environment-friendly treatment, so that the air pollution during the production of the sulfur asphalt is reduced.

5. The warm-mixed sulfur asphalt can be added with more sulfur, so that the application of sulfur in the asphalt is promoted, the market of sulfur is expanded, the road construction cost is reduced, and a large amount of asphalt resources are saved.

6. The method has the advantages of low device investment, simple production process, low operation cost, safety, energy conservation, no solvent pollution to the environment and the like.

Detailed Description

The technical solution of the present invention will be described in detail with reference to the following examples, but the present invention is not limited to the following examples. Unless otherwise specified, the following percentages are mass percentages.

Example 1

The method comprises the following three steps: preparing a warm-mixing agent, (II) preparing warm-mixing sulfur asphalt, and (III) preparing a warm-mixing sulfur asphalt mixture.

Preparation of warm mixing agent

(1) Preparation and charging

Water is filled below the sweating dish plate; connecting a sealing system of the sweating dish with a pressurizing buffer tank and a compressor; a decompression buffer tank is arranged at the lower part of the sweating dish and is connected with a vacuum pump; connecting the sweating dish jacket and the movable coil pipe with a circulating system, and fixing the coil pipe on the sweating dish; the heat conducting oil is used as a medium, the heating function of the circulating system is started, and the circulating oil is heated to 94 ℃.

Taking polyethylene wax which is a byproduct of a high-density polyethylene device in a medium petroleum Jilin petrochemical ethylene plant as a raw material (the dropping melting point is 90.3 ℃, the penetration degree at 25 ℃ is 43 dmm, the penetration degree at 55 ℃ is more than 200 dmm, and the polyethylene wax contains a large amount of low-melting-point substances from the penetration degrees at 25 ℃ and 55 ℃), heating to 94 ℃ to melt, adding azodicyclohexyl formonitrile accounting for 14.0 percent of the weight of the raw material, stirring uniformly, and then adding into a sweating dish.

(2) Crystallization of

Starting the refrigeration function of the circulating system, and reducing the temperature of the wax layer to 80.0 ℃ at the cooling rate of 2.5 ℃/h. The refrigeration function of the circulation system is closed.

(3) Temperature rising-constant temperature sweating

Draining the pad water of the sweating dish. The outlet of the sweating dish is connected with the intermediate storage tank to receive wax; installing a sealing system at the upper part of the sweating dish; starting a compressor and keeping the pressure in a pressurizing buffer tank to be stable at 1.1-1.3 atmospheric pressures (gauge pressure), and keeping the atmospheric pressure below a sweating dish plate; starting a heating function of a circulating system, and raising the temperature of the wax layer to 85.0 ℃ at a temperature rise rate of 2.5 ℃/h; the compressor is stopped.

Starting a vacuum pump and keeping the pressure in the decompression buffer tank stable at-0.4 to-0.6 atmospheric pressure (gauge pressure), and keeping the atmospheric pressure above the wax layer at normal pressure; the temperature of the wax layer is continuously increased to 90.0 ℃ at the temperature increasing rate of 2.5 ℃/h and is kept constant for 4.0 hours, so that the solid components and the liquid components in the wax layer are fully separated. Stopping the vacuum pump and stopping the sweating process.

(4) Discharging

And (3) switching an outlet of the sweating dish to a product tank, continuously raising the temperature of the heat-conducting oil to 110 ℃, and melting and taking out the wax to obtain the asphalt warm-mixing agent.

The yield of the asphalt warm-mixing agent product is 36.7 percent (relative to the polyethylene wax as a by-product of the raw material). The asphalt warm-mixing agent has the product properties: the melting point of the drops is 94.8 ℃, the penetration degree at 25 ℃ is 2 dmm, and the penetration degree at 55 ℃ is 23 dmm. It can be seen from the penetration at 25 deg.C and 55 deg.C that the low-melting substance in the product has been substantially removed.

(II) preparing warm-mixed sulfur asphalt

Weighing 7kg of the warm-mix agent (I), adding the warm-mix agent (I) into No. 50 solvent deoiled asphalt of crude oil in sand with the mass of 33kg and the temperature of 140 ℃, and stirring for 60min to obtain warm-mix asphalt; then 60kg of sulfur is added into the warm mix asphalt and stirred for 120min, thus obtaining the warm mix sulfur asphalt (number A-1) of the invention. The bitumen properties and the use temperatures are shown in Table 1.

(III) preparing warm-mixed sulfur asphalt mixture

Heating a special asphalt mixture stirring kettle to 150 ℃ in advance and keeping the temperature constant; preparing Liaoyang andesite aggregate into AC-10 aggregate with a total mass of 91kg, and heating to 150 ℃ for later use; weighing 6.0kg of the warm-mixed sulfur asphalt (A-1), and heating to 150 ℃ for later use; 3.0kg of mineral powder is weighed. After the temperature of the stirring kettle, the aggregate and the asphalt is constant, adding the aggregate and the mineral powder into the stirring kettle together, and stirring for 2 minutes; and then adding the weighed warm-mixed sulfur asphalt into a stirring kettle, and stirring for 3 minutes to obtain the warm-mixed sulfur asphalt mixture. The warm-mixed sulfur asphalt mixture of the invention is prepared into various mixture test pieces and is subjected to performance evaluation experiments, and the results are shown in table 2.

Example 2

Preparation of warm mixing agent

(1) Preparation and charging

And water is filled below the sweating dish plate. Connecting a sealing system of the sweating dish with a pressurizing buffer tank and a compressor; a decompression buffer tank is arranged at the lower part of the sweating dish and is connected with a vacuum pump; connecting the sweating dish jacket and the movable coil pipe with a circulating system, and fixing the coil pipe on the sweating dish; the heat conducting oil is used as a medium, the heating function of the circulating system is started, and the circulating oil is heated to 94 ℃.

Taking polyethylene wax byproduct of a high-density polyethylene device in a China Petroleum Jilin petrochemical ethylene plant as a raw material (the property is the same as that of the embodiment 1), heating the raw material to 94 ℃ for melting, then adding dibenzoyl peroxide accounting for 0.03 percent of the weight of the raw material, stirring the mixture evenly, and then adding the mixture into a sweating dish.

(2) Crystallization of

Starting the refrigeration function of the circulating system, and reducing the temperature of the wax layer to 80.0 ℃ at the cooling rate of 2.5 ℃/h. The refrigeration function of the circulation system is closed.

(3) Temperature rising-constant temperature sweating

Draining the pad water of the sweating dish. The outlet of the sweating dish is connected with the intermediate storage tank (I) to receive wax; installing a sealing system at the upper part of the sweating dish; starting a compressor and keeping the pressure in a pressurizing buffer tank to be stable at 1.1-1.3 atmospheric pressures (gauge pressure), and keeping the atmospheric pressure below a sweating dish plate; starting a heating function of a circulating system, and raising the temperature of the wax layer to 85.0 ℃ at a temperature rise rate of 2.5 ℃/h; the compressor is stopped.

Starting a vacuum pump and keeping the pressure in the decompression buffer tank stable at-0.4 to-0.6 atmospheric pressure (gauge pressure), and keeping the atmospheric pressure above the wax layer at normal pressure; the temperature of the wax layer is continuously increased to 90.0 ℃ at the temperature increasing rate of 2.5 ℃/h and is kept constant for 4.0 hours, so that the solid components and the liquid components in the wax layer are fully separated. Stopping the vacuum pump and stopping the sweating process.

(4) Discharging

And (3) switching an outlet of the sweating dish to a product tank, continuously raising the temperature of the heat-conducting oil to 110 ℃, and melting and taking out the wax to obtain the asphalt warm-mixing agent.

The yield of the asphalt warm-mixing agent product is 42.2% (relative to polyethylene wax by-produced in the raw material polyethylene), and the properties are as follows: the melting point of the solution was 94.8 ℃, the penetration degree was 6 dmm at 25 ℃ and 38 dmm at 55 ℃. It can be seen from the 25 ℃ and 55 ℃ penetration that the low melting substances have been substantially removed in the antiperspirant product.

(II) preparing warm-mixed sulfur asphalt

Weighing 0.5kg of the warm-mix agent (II), adding into No. 90 oxidized asphalt of Liaohe crude oil with the mass of 79.5kg and the temperature of 110 ℃, and stirring for 30min to obtain warm-mix asphalt; then 20kg of sulfur is added into the warm mix asphalt and stirred for 40min, thus obtaining the warm mix sulfur asphalt (number A-2) of the invention. The bitumen properties and the use temperatures are shown in Table 1.

(III) preparing warm-mixed sulfur asphalt mixture

Heating a special asphalt mixture stirring kettle to 120 ℃ in advance and keeping the temperature constant; preparing the basalt aggregate of iron ridge into aggregate with the grading of AC-13, wherein the total mass is 95kg, and heating to 120 ℃ for later use; weighing 4.0kg of the warm-mixed sulfur asphalt (A-2), and heating to 120 ℃ for later use; 1.0kg of mineral powder is weighed. After the temperature of the stirring kettle, the aggregate and the asphalt is constant, adding the aggregate and the mineral powder into the stirring kettle together, and stirring for 2 minutes; and then adding the weighed warm-mixed sulfur asphalt into a stirring kettle, and stirring for 3 minutes to obtain the warm-mixed sulfur asphalt mixture. The warm-mixed sulfur asphalt mixture of the invention is prepared into various mixture test pieces and is subjected to performance evaluation experiments, and the results are shown in table 2.

Comparative example 1

Weighing 0.5kg of polyethylene byproduct polyethylene wax (the nature is shown as the sweating raw material in example 1), adding into No. 90 oxidized asphalt of Liaohe crude oil with the mass of 79.5kg and the temperature of 110 ℃, and stirring for 30min to obtain comparative asphalt; then, 20kg of sulfur was added thereto and stirred for 40min to obtain comparative sulfur asphalt (No. D-1). The bitumen properties and the use temperatures are shown in Table 1.

Heating a special asphalt mixture stirring kettle to 120 ℃ in advance and keeping the temperature constant; preparing the basalt aggregate of iron ridge into aggregate with the grading of AC-13, wherein the total mass is 95kg, and heating to 120 ℃ for later use; weighing 4.0kg of the comparative sulfur asphalt (D-1), and heating to 120 ℃ for later use; 1.0kg of mineral powder is weighed. After the temperature of the stirring kettle, the aggregate and the asphalt is constant, adding the aggregate and the mineral powder into the stirring kettle together, and stirring for 2 minutes; and adding the weighed comparative sulfur asphalt (D-1) into a stirring kettle, and stirring for 3 minutes to obtain a comparative sulfur asphalt mixture. The comparative sulfur asphalt mixture was prepared into various mixture test pieces and subjected to performance evaluation experiments, and the results are shown in table 2.

TABLE 1 asphalt formulation and Properties and application temperature comparison

As can be seen from Table 1, the high temperature viscosity of the warm-mix sulfur asphalt of the invention is significantly lower than that of the corresponding matrix asphalt and the comparative asphalt, so that the blending and forming temperature is reduced by 20-25 ℃. Compared with the corresponding matrix asphalt and the contrast asphalt, the warm-mixed sulfur asphalt has the advantages that the softening point and the viscosity at 60 ℃ are obviously improved and the ductility at 10 ℃ is obviously increased when the penetration degree is basically the same, which shows that the warm-mixed sulfur asphalt not only can achieve the warm-mixed effect, but also is superior to the corresponding matrix asphalt and the common sulfur asphalt in the aspects of high-temperature stability and low-temperature ductility.

According to comparison of film experiment results, the warm-mixed sulfur asphalt prepared by the warm-mixing agent provided by the invention has obviously better ageing resistance than that of comparative asphalt, the thermal stability of the asphalt is improved, and the thermal ageing resistance is improved.

TABLE 2 asphalt mixture ratio and property comparison

Note: [1] JTG F40-2004 technical Specification for construction of asphalt road surface for road.

As can be seen from Table 2, the warm mix sulfur asphalt mixture of the invention has significantly improved rutting dynamic stability, increased trabecular bending failure strain, and other indexes meeting the technical specification requirements. The warm-mixed sulfur asphalt mixture of the invention not only improves the anti-rutting performance, but also gives consideration to the low-temperature performance.

Claims (16)

1. The warm-mixed sulfur asphalt mixture is characterized by comprising the following components in parts by mass based on the total mass of the mixture: 4.0-6.0 parts of warm-mixed sulfur asphalt, 1.0-3.0 parts of mineral powder and 91.0-95.0 parts of aggregate; the warm-mixed sulfur asphalt comprises the following components in parts by mass:

33-79.5 parts of matrix asphalt;

0.5-7 parts of warm mixing agent;

20-60 parts of sulfur;

the warm mixing agent is prepared by the following method:

(1) charging: heating and melting polyethylene wax serving as a byproduct of polyethylene, adding oil-soluble and decomposable organic substances for generating gas into the polyethylene wax, uniformly stirring, and then putting the mixture into a sweating device; the melting point of the polyethylene wax is 70-98 ℃;

(2) and (3) crystallization: cooling the wax layer to a cooling termination temperature of 5-30 ℃ below the dropping melting point of the raw material at a speed of 2.0-4.0 ℃/h;

(3) temperature rise-constant temperature sweating: heating at the speed of 1.5-3.5 ℃/h, stopping sweating after the wax layer reaches the preset temperature and is kept at the constant temperature for 0.1-5.0 hours, and forcing airflow to pass through the wax layer in the sweating process; the preset temperature is-10 ℃ of the drop melting point of the target product to the drop melting point of the target product;

(4) discharging: discharging the remainder in the sweating device to obtain the warm mixing agent.

2. The warm-mix sulfur asphalt mixture according to claim 1, wherein the oil-soluble decomposable gas-generating organic substance is selected from the group consisting of organic azo compounds, sulfonyl hydrazide compounds, organic nitroso compounds, and organic peroxides.

3. The warm-mix sulfur asphalt mixture according to claim 2, wherein the oil-soluble decomposable gas-generating organic substance is an organic azo compound and/or an organic peroxide.

4. The warm-mix sulfur asphalt mixture according to claim 1, wherein the amount of the oil-soluble decomposable gas-generating organic substance added is 0.01 to 15.00% by weight of the raw materials.

5. The warm-mix sulfur asphalt mixture according to claim 4, wherein the amount of the oil-soluble decomposable gas-generating substance added is 0.03 to 8.00% by weight of the raw materials.

6. The warm mix sulfur asphalt mixture according to claim 2, wherein the organic azo compound is selected from the group consisting of azobisisoheptonitrile, azobisisobutyronitrile, azobisformamide, and azobiscyclohexylcarbonitrile; the sulfonyl hydrazide compound is selected from a group of substances consisting of benzenesulfonyl hydrazide, p-toluenesulfonyl hydrazide and 4, 4' -oxidized bis (benzenesulfonyl hydrazide); the organic nitroso compound is selected from dinitrosopentamethylenetetramine and/or N, N '-dimethyl N, N' -dinitrosophthalamide; the organic peroxide is selected from the group consisting of dibenzoyl peroxide, lauroyl peroxide, isopropyl peroxydicarbonate and dicyclohexyl peroxydicarbonate.

7. The warm-mix sulfur asphalt mixture according to claim 1, wherein the temperature reduction termination temperature in the step (2) is 8 ℃ to 20 ℃ below the melting point of the sweating raw material droplets.

8. The warm mix sulfur asphalt mixture according to claim 1, wherein the forced air flow in step (3) is achieved by increasing the air pressure above the wax layer and/or decreasing the air pressure below the wax layer to form a pressure difference between the upper and lower sides of the wax layer, wherein the pressure difference is 0.1-5.0 atm.

9. The warm-mix sulfur asphalt mixture according to claim 1, wherein the time for maintaining the constant temperature in step (3) is 1.0 to 5.0 hours.

10. The warm-mix sulfur asphalt mixture according to claim 1, wherein the forced air flow in step (3) is performed through the wax layer at an initial stage of the temperature increase.

11. The warm mix sulfur asphalt mixture according to claim 8, wherein the forced air flow through the wax layer is achieved by increasing the air pressure above the wax layer, applying a gauge pressure of 0.2 to 2.0 atmospheres above the wax layer, and maintaining the atmospheric pressure below the wax layer.

12. The warm mix sulfur asphalt composition according to claim 8, wherein said forced air flow through the wax layer is achieved by reducing the air pressure below the wax layer, maintaining atmospheric pressure above the wax layer, and maintaining a gauge pressure of-0.2 to-1.0 atmospheres below the wax layer.

13. The warm-mix sulfur asphalt mixture according to claim 1, wherein the aggregate is at least one selected from the group consisting of limestone, basalt, andesite, and granite aggregate.

14. The warm-mix sulfur asphalt mixture according to claim 1, wherein the mineral powder is ground from ore, and the proportion of particles with a particle size of less than 0.075mm is more than 70% by mass fraction.

15. A process for preparing a warm-mix sulphur asphalt mix as claimed in any one of claims 1 to 14, comprising the steps of:

① preparing warm-mixed sulfur asphalt by heating the matrix asphalt to 110-140 deg.C, stirring, adding warm-mixing agent, adding sulfur, and stirring;

②, respectively heating the stirring kettle and the aggregate to 110-140 ℃, simultaneously adding the aggregate and the mineral powder into the stirring kettle, and stirring;

③ heating the warm-mixed sulfur asphalt to a molten state, adding into a stirring kettle, mixing with the aggregate and the mineral powder, and stirring to obtain the warm-mixed sulfur asphalt mixture.

16. The preparation method according to claim 15, wherein the warm-mixing agent is added in step ①, the stirring reaction time is 30-60 min, and the stirring reaction time is 40-120 min after the sulfur is added.