Five key technologies for the utilization of the h

Waste tire utilization: break through five key technologies

-- cleaner production technology series report II of the national science and technology support plan

in recent years, the contradiction between the continuous sharp increase of waste tires and the lack of rubber resources in China has become increasingly acute. In 2010, China's waste tires reached 233 million (about 8.6 million tons), surpassing the United States and ranking first in the world. However, 75% of natural rubber and 45% of synthetic rubber in China depend on imports, ranking first in the country's large strategic reserve resources. Therefore, vigorously developing the comprehensive utilization of waste tire resources can not only turn waste into treasure, greatly alleviate the shortage of rubber resources in China, but also eliminate the environmental pollution caused by waste tires, which is in line with the major strategic needs of national energy conservation and emission reduction

"a large number of waste tires are not only not easy to decay, but also easy to cause fires and breed mosquitoes, which has become a common problem faced by countries all over the world. At the same time, waste tires, as a resource placed in the wrong location, have attracted more and more attention all over the world." In an interview, Professor liushuangxi of Nankai University, who is in charge of the national "11th Five Year Plan" science and technology support project of ultra-fine grinding and recycling technology development of waste tires, said that waste tires are full of treasure: containing 58% - 60% of rubber mixture, rubber powder and recycled rubber can be produced, 22% - 24% of synthetic fibers such as nylon can be processed into plastic products, and 16% - 24% of steel wires are raw materials of high-quality springs

how can we turn waste into treasure and turn corruption into magic? Nankai University, together with four industry leading enterprises, has made breakthroughs in five key technologies and built four 10000 ton waste tire comprehensive utilization demonstration bases, giving a strong answer

rubber powder and asphalt mixture modification

waste tire rubber powder modified asphalt has been used abroad for more than 30 years, while it has just started in China. Liu Shuangxi introduced that using rubber powder modified asphalt pavement can improve the high-temperature stability, low-temperature crack resistance, aging resistance and durability of asphalt, and can effectively reduce road noise, reduce road reflection, and improve the anti-skid effect of pavement. At the same time, the modification of road asphalt with waste rubber and plastic materials can replace the widely used and expensive polymer modifiers such as styrene butadiene styrene copolymer (SBS) and styrene butadiene rubber, which can effectively reduce the cost of road construction and save oil resources

the project team has developed the activation of waste tire rubber powder and the production technology of wet modified asphalt, and built a production demonstration base with an annual output of 100000 tons of certified rubber powder modified asphalt, which has become a qualified supplier due to product complaints and environmental problems. Through the activation and modification of rubber powder, the mixing amount of low mesh rubber powder in asphalt can reach more than 20%, the process and production time can be greatly shortened, and it is preliminarily estimated that energy saving can be more than 60%. From 2007 to 2010, the project team used rubber powder modified asphalt to pave 455.3 kilometers of roads, and its research results were applied to landmark projects such as Shanghai WorldExpo, China Singapore eco city, Binhai New Area, Airbus A320 final assembly transportation road and the construction of many expressways in China

fine classification and fiber separation

Liu Shuangxi told that 80~200 mesh fine rubber powder has higher production than low mesh rubber powder (below 80 mesh). American companies have launched new composite membrane regeneration technology products with added value, which can be applied to many fields such as coatings, waterproof coiled materials, rubber and plastic composites. However, the separation of fine rubber powder cannot be achieved by using traditional screening technology. Therefore, how to realize the classification of fine rubber powder and the separation of fiber and rubber powder is the key

through the research and development of fine classification and fiber separation technology of waste tire crushing at room temperature, the project team has successfully solved the separation of 80 to 200 meshes by using the air spinning powder separation technology with variable speed and variable angle. Now we will expand it to the separation of larger-scale fine rubber powder that is expected to be used in the market. The classification passing rate of more than 80 mesh rubber powder is more than 94%, the proportion of 200 mesh ultra-fine rubber powder is 50%, the fiber separation rate in rubber powder is more than 99%, and the metal content is ≤ 0.002%, far exceeding the national standard (0.02%) and the American Standard (0.01%). The completed fine rubber powder production demonstration base with an annual treatment of 16000 tons of waste tires has realized the centralized computer automatic control of the whole production line, and is one of the most automated fine rubber powder production lines for waste tires in China at present. The waste tire rubber powder produced by the demonstration enterprise has been used as the raw material of rubber powder modified asphalt in Beijing 2008 "Green Olympics" project, including the reconstruction of the Third Ring Road, Sanyuan bridge, Siyuan bridge, Kandan bridge, and the construction and reconstruction of water sports center roads

pyrolysis to fuel oil and activated carbon black

at present, the low added value of pyrolysis products is the main factor restricting the promotion of waste tire pyrolysis technology. On the basis of developing a complete set of waste tire pyrolysis process, the project team focused on the high-value research of waste tire pyrolysis oil and pyrolysis carbon black, successfully developed a complete set of waste tire non stripping micro negative pressure continuous pyrolysis process, and built a waste tire pyrolysis production demonstration base with an annual treatment of 10000 tons of waste tires, cracking waste tires into 40% - 45% fuel oil, 35% carbon black, 10% steel wire and 10% combustible gas, without wastewater and waste residue discharge, The gas emission meets the national secondary standard

after treatment, pyrolytic carbon black can be used as semi reinforced carbon black for tires. At present, it has been used by tire manufacturers such as Zhongce tire and shanglun group. The pyrolytic carbon black can be made into activated carbon by further activation treatment, and the specific surface area can reach more than 1000 square meters/gram. In addition, the waste tire activated carbon can be used as an adsorbent for treating dye wastewater and indoor air pollution; It can be used as electrode material of super capacitor; It can also be used as a catalyst carrier in new energy catalysis and environmental catalysis, which greatly improves the added value of waste tire pyrolysis carbon black

high temperature dynamic desulfurization of crushed materials

at present, most reclaimed rubber products in China are low-quality reclaimed rubber, which not only limits the application field of reclaimed rubber, but also causes a waste of rubber resources. Through the research and development of high-temperature dynamic desulfurization process technology for crushed materials, the project team developed high-quality recycled rubber products with high tensile strength and large elongation at break, and built a production demonstration base with an annual output of 10000 tons of high-quality recycled rubber. The authoritative testing department tested that the tensile strength of the product reached 19.5 MPa, the elongation at break reached 550%, and the Mooney viscosity was 48

establish technical specifications and product standards

in recent years, the construction of standardization system lags behind the industrial development, which has become an important factor restricting the healthy development of China's renewable resources industry. Therefore, in terms of the research and formulation of waste tire comprehensive utilization product standards, the project team participated in the formulation of one national standard and one industry technical guide, and organized the formulation of three industry standards and one local standard

in addition, Liu Shuangxi revealed that the project team also carried out carbon emission benefit analysis of key industries such as rubber powder modified asphalt, rubber powder and recycled rubber, and accounted for the carbon dioxide emission reduction benefits of the waste tire comprehensive utilization industry. Through the cleaner production audit of waste tire thermal cracking, rubber powder, rubber powder modified asphalt and reclaimed rubber related enterprises, taking eight aspects of cleaner production as the starting point, and comprehensively considering the economic, technical and environmental indicators of the production process, the cleaner production technical specifications and cleaner production standards for rubber powder production, reclaimed rubber production and thermal cracking production have been formed

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