product performance
Petroleum asphalt is black and shiny, and has high temperature sensitivity. Petroleum asphalt can be classified according to the following system:
manufacturing method
(1) distillation method: crude oil is distilled at normal pressure to separate out light fractions such as gasoline, kerosene and diesel oil, and then vacuum distillate oil (residual pressure 10~ 100mmHg) is separated by vacuum distillation. When the residual residue meets the specifications of road asphalt, asphalt products can be directly produced. The obtained asphalt, also called straight-run asphalt, is the main method to produce road asphalt.
(2) Solvent precipitation method: nonpolar low-molecular-weight alkane solvents have different solubility for each component in vacuum residue. By using the solubility difference, each component can be separated, so that the components that are unfavorable to asphalt properties can be removed from vacuum residue to produce asphalt products that meet the specifications. This is the solvent precipitation method.
(3) Oxidation method: At a certain range of high temperature, air is blown into vacuum residue or deoiled asphalt to change its composition and performance, and the obtained product is called oxidized asphalt. Under the action of high temperature and blowing, vacuum residue will vaporize, and a series of reactions such as dehydrogenation, oxidation, polymerization and condensation will occur at the same time. This is a very complex multi-component interaction comprehensive reaction process, which is not only an oxidation reaction, but also known as oxidation method and oxidized asphalt, air blowing method and air blowing asphalt.
(4) Blending method: Blending method refers to blending the four components of asphalt composed of the same crude oil again according to the proportion required by quality requirements, and the obtained product is called synthetic asphalt or recycled asphalt. With the development of technology, the sources of blending components have been expanded. For example, the residues or components of the same crude oil or different crude oils after primary and secondary processing with various industrial waste oils can be used as blending components, which reduces the dependence of asphalt production on oil source selection. With the increasing shortage of crude oil suitable for asphalt production, the flexibility and economy of blending methods have been paid more and more attention and widely used.
(5) Emulsification method: The surface tension of asphalt and water is very different, and they will not be mutually soluble at room temperature or high temperature. However, when asphalt is subjected to high-speed centrifugation, shearing, mashing and other mechanical actions, it becomes particles with a particle size of 0. 1~5 microns and is dispersed in the water medium containing surfactant (emulsifier-stabilizer). Because the emulsifier can be directionally adsorbed on the surface of asphalt particles, the interfacial tension between water and asphalt is reduced, and asphalt particles form a stable dispersion system in water, which is an oil-in-water emulsion. This dispersion system is brown, with asphalt as dispersed phase and water as continuous phase, and has good fluidity at room temperature. In a sense, emulsified asphalt is to "dilute" asphalt with water, thus improving the fluidity of asphalt.
(6) Modified asphalt: Many changes have taken place in modern highways and roads: the traffic flow and driving frequency have increased sharply, the axle load of freight cars has increased continuously, and one-way driving in separate lanes is widely implemented, which requires further improvement of the pavement's anti-fluidity, that is, the ability to resist rutting at high temperature; Improve flexibility and elasticity, that is, crack resistance at low temperature; Improve wear resistance and prolong service life. Long-span prestressed roof panels are widely used in modern buildings, which require that the roof waterproof material adapt to large displacement, be more resistant to harsh high and low temperature weather conditions, have good durability, be self-adhesive, be convenient for construction and reduce maintenance workload. These changes in the use environment pose a severe challenge to the performance of petroleum asphalt. In order to meet the above demanding requirements, people began to pay attention to the modification of petroleum asphalt. After decades of research and development, a wide variety of modified road asphalt, waterproofing membrane and coatings have appeared, showing certain practical engineering effects. However, in view of the fact that the price of modified materials is usually 2~7 times higher than that of ordinary petroleum asphalt, users have not fully grasped the engineering properties of materials, and the output of modified asphalt has grown slowly. The modified road asphalt is mainly used for paving applications in special occasions such as airport runways, waterproof bridge decks, parking lots, sports fields, heavy traffic pavements, intersections and road bends. The application of modified asphalt in road network maintenance and reinforcement in Europe has greatly promoted the wide application of modified road asphalt. Modified asphalt waterproofing membrane and coating are mainly used for waterproofing of high-grade buildings. With the progress of science and technology and the development of economic construction, the variety development and production technology of modified asphalt will be further promoted. The variety and preparation technology of modified asphalt depend on the type and dosage of modifier and the composition and performance of matrix asphalt (original asphalt). Because there are many kinds and shapes of modifiers, in order to form a uniform material for engineering application with petroleum asphalt, various types of modifiers have been evaluated for many years, and corresponding formulas and preparation methods have been developed, but most of the modified asphalt that has been applied to engineering at present belongs to patented technology and patented products.
Main applications
It is mainly used as infrastructure materials, raw materials and fuel, and its application scope is such as transportation (roads, railways, aviation, etc. ), construction, agriculture, hydraulic engineering, industry (extractive industry, manufacturing), civil engineering and other departments.
Packaging and storage
Asphalt may need to be stored in storage tanks during production and use. If handled properly, asphalt can be heated repeatedly and kept at a high temperature for a long time without seriously damaging its performance. However, if exposed to oxygen, light and overheating, the asphalt will become hard. The most obvious sign is that the softening point of asphalt increases, the penetration decreases and the ductility becomes worse, which affects the performance of asphalt.
Heat output
Asphalt is stored in a large storage tank. When it is used for export, it is necessary to heat the asphalt in the storage tank to improve the fluidity of asphalt, so as to export it smoothly and quickly. The heat source required for heating output is generally heat transfer oil. According to the petrochemical technology promotion center, the traditional heating method has the following disadvantages:
1, the heating process is not economical. When only a small amount of asphalt needs to be poured out, all the asphalt in the whole tank should be heated, and the amount of asphalt heated is several times of this time, which makes a large amount of heat transfer oil useless.
2. The asphalt temperature of each part of the storage tank is unbalanced. The asphalt temperature near the heater is higher, and the asphalt temperature far away from the heater is lower, which seriously affects the fluidity of oil products.
3, affect the quality of asphalt. Repeated heating of asphalt in the tank produces a large number of fine decomposition products, which has a certain impact on the color quality of asphalt and increases the cost of post-treatment.
Local heating technology: after the heat transfer oil enters the "local rapid heater", the asphalt in the asphalt tank is heated locally, and as much asphalt as needed is heated, so that the whole tank does not need to be heated repeatedly, and the asphalt output is faster while saving energy. The flow deformation of asphalt pavement is the most common phenomenon of asphalt pavement damage in the world. According to statistics, about 80% of pavement maintenance statistics are caused by rutting. Through engineering practice, it is found that rock asphalt modified asphalt has great advantages in high temperature stability, which can solve rutting and early diseases caused by heavy traffic and overweight and overload of high-grade asphalt pavement.
Rock asphalt is an asphalt substance produced by the combined action of heat, pressure, oxidation, catalyst and bacteria after hundreds of millions of years of deposition and change of petroleum. Often used as matrix asphalt modifier. The physical properties of rock asphalt are close to "coal".
The proven natural rock asphalt mineral resources in China are mainly distributed in Xinjiang, Qinghai and Qingchuan, Sichuan. Qingchuanyan asphalt mine is located in Longmenshan area in northern Sichuan, where China enjoys the reputation of a land of abundance. The initial proven reserves are more than 3 million tons, and the prospective reserves are100000 tons. Known by experts as "a rare natural asphalt ore body in China and even the world", its reserves rank first in China. Natural rock asphalt in North Sichuan is mainly composed of asphaltene with molecular weight as high as 10000, and its chemical components are carbon 8 1.7%, hydrogen 7.5%, oxygen 2.3%, nitrogen 1.95%, sulfur 4.4% and aluminum1. Among them, the contents of carbon, hydrogen, oxygen, nitrogen and sulfur are high, and almost every asphaltene macromolecule contains polar functional groups of the above elements, which makes it strongly adsorbed on the rock surface. 2065438+On May 25th, 2004, China Army made its first test flight on the runway of the third generation fighter plane on Min Zheng Expressway. Sun, a military expert of Yangzi Evening News, explained that the requirements for aircraft taking off and landing on the expressway runway are very strict, which is different from the standard of general expressway laying. One of the key points is the "material" of this expressway. A special layer of modified asphalt concrete was laid on the top of Min Zheng Expressway. The reporter learned in an interview with Southeast University yesterday that this kind of "super asphalt" with a high temperature of 300℃ and a low temperature of MINUS 30℃ was jointly developed by Southeast University and Jurong Ningwu Technology Development Company.
"Super" asphalt
Resistant to 300℃ high temperature, acid and alkali and elastic.
"Min Zheng Expressway (Zhengzhou to Quan Min) is an important communication channel in the expressway network of Henan Province, and the whole line adopts the technical standard of two-way four-lane expressway. In 2008, the construction of Min Zheng Expressway began, and Zhang Zhanjun, a postdoctoral fellow at Southeast University, was in charge. The domestic' super asphalt' used to lay this expressway was developed and manufactured in Jiangsu. " Researcher Zhu Jianshe, assistant president of Southeast University, told reporters that this kind of asphalt is called "epoxy asphalt".
Different from ordinary asphalt, epoxy asphalt is made by adding epoxy resin into asphalt, and the epoxy resin reacts with curing agent, which makes asphalt have high strength and toughness and little deformation at high and low temperatures. This material looks very simple, as long as asphalt and epoxy resin are mixed in a certain proportion. However, it is more difficult to get the right proportion of materials than to ascend to heaven. The research is almost carried out in the blank. "Just like a person's blood type, blood transfusion should be matched. Asphalt and epoxy resin are obviously incompatible, which is the difficulty.
How awesome is this epoxy asphalt independently developed by Jiangsu? Zhu Jianshe introduced that in the repeated laboratory, the high temperature of domestic epoxy asphalt is 300℃ and the low temperature is MINUS 30℃. "When the jet plane takes off and lands, the gas temperature reaches 1000℃, and ordinary asphalt can be' melted' in an instant." This asphalt is also resistant to corrosion. "We have done experiments, soaking epoxy asphalt in acid, alkali and salt for more than a month, and there is almost no change when it is taken out." Another feature of this asphalt is toughness. "In the past, most of our roads were rigid, the cars were difficult to drive, the noise was high, and the wheels and roads were badly worn. The new asphalt has certain elasticity, which provides buffering force for the take-off and landing of heavy aircraft, and the aircraft is not easy to wear. " Another key point is that this material has strong water absorption and can penetrate the accumulated water caused by rain and snow.
Road to research and development
American asphalt paved on the Second Yangtze River Bridge is half cheaper than domestic asphalt.
However, before 2006, the manufacturing technology of this environmentally friendly asphalt with high temperature resistance, low temperature resistance and pressure resistance was monopolized by the United States and the technology was blocked. In 200 1 year, the team led by Professor Huang Wei, an academician of China Academy of Engineering, used "epoxy asphalt" from the United States when laying the Second Yangtze River Bridge. If ordinary asphalt pavement is used, in the season with large temperature difference, the bridge deck is easy to crack and slip, and it will fall into the strange circle of "repeated repairs and repeated repairs". "But the price of epoxy asphalt in the United States is surprisingly high, with a ton of more than 70,000 yuan. When the Second Bridge was completed, Professor Huang Wei said that China's own epoxy asphalt paving materials and complete sets of technologies must be developed, and the core technology of major national projects must be in the hands of us in China! "
200 1 southeast university established the "new epoxy asphalt manufacturing equipment and engineering application project team", with professor Huang Wei as the team leader and Zhu Jian as the main person in charge, and chose Jurong Ningwu to cooperate in Industry-University-Research. "Professors from School of Transportation, School of Chemistry and Chemical Engineering, and School of Automation of Southeast University and technicians from Ningwu Science and Technology worked together for more than six years, and finally mastered the manufacturing method of this special asphalt." "The cost of the United States is more than 70,000 tons, and our price is only half, more than 30,000."