Industrial shredder for plastic recycling : Plastic waste recovery and regeneration
Plastic products with its light weight, waterproof, durable, beautiful products, mature production technology and other characteristics, are widely used and show a growing trend year by year, China has become one of the world's top ten plastic products producer, but also the first consumer of plastic materials
Plastic science and technology brings great material civilization at the same time, the emergence of a large number of plastic waste to people posed a serious challenge, but also gave us new opportunities.
(1) the pollution caused by plastic waste, commonly known as "white pollution", it is increasingly causing people's great concern, disregard its existence or improper treatment will cause some serious risks, such as: plastic waste in the environment is not easy to rot, piling up garbage, pollution point increase;
(2)The plastic film, such as agricultural film into the soil, is not easy to decompose to prevent the permeability of the soil, so that the soil quality becomes bad, affecting the growth of crops;
(3)Plastic waste has accounted for more than 60% of the Marine flotsam, endangering Marine life and maritime safety.
Therefore, the recycling and utilization of plastic waste has reached a point that cannot be ignored.At present, the plastic waste recycling technology can be divided into five aspects.
1. The direct recycling and modified recycling of waste plastics are the most important methods for the utilization of waste plastics, and their technical investment and cost are relatively low. They have become the main methods for the utilization of waste plastics as renewable resources in many countries.Compared with the modified recycling, the direct recycling technology investment and cost is relatively lower, the choice is more common, but the modified recycling is the development direction.
1.1 direct recycling this is the recycling of waste plastics directly after classification, washing, crushing, granulation processing, which also contains some appropriate auxiliary components (such as stabilizer, prevent ageing agent colorants, etc.) to cooperate, to improve the processing performance and appearance to join these additives are only or anti-aging effect, does not improve the basic properties of the recycled products.A Japanese construction company will scrap the old foam plastic after infrared radiation heating, its volume is reduced to less than 20%, and then mixed with special cement, made of "rice flower sugar" shape building materials, as a low-cost soundproof material, has a good soundproof effect, a wide range of USES.
This is the modification of recycled materials through mechanical blending or chemical grafting technology such as toughening, strengthening, combined, composite, activated particle filled blending modification, as well as cross-linking, grafting, chlorination and other chemical modification.The properties of the modified regenerated products, especially the mechanical properties, can be significantly improved and can be used as higher grade regenerated products.But the process route is more complex, and sometimes specific mechanical equipment is required.Almost all thermoplastic waste plastics can be collected, sorted, cleaned, crushed and dried and then hot melted. With all kinds of plastic molding equipment, we can produce recycled plastic plates, tubes, bars, parts and containers.For example, disposable foamed polystyrene (EPS) foam tableware, which has been explicitly prohibited by the state, can also be modified and recycled, which can solve the problem of the tableware prohibition.
The method is as follows. First, EPS foam box can be cleaned by saponification method. After cleaning and drying, EPS foam can be crushed and defoamed by single-screw extruder.The tensile strength of LDPE/PS composite material obtained is higher than that of pure LDPE, and its elongation at break, impact strength and recovery material have very significant improvement, which can be used to produce products with low strength requirements, such as cover wire plate, daily miscellaneous parts.The flow chart is shown.
Foam lunch boxes;Soaking pool coarse crushing mixing hot water washing dry blending renewable products waste EPS foam snack box modified chemical degradation of waste plastics recycling process technology the basic principle is to waste plastic zhongyuan resin polymer is thoroughly macromolecular chain points shaw solution to make it back to the low molecular state, some components are its monomer, other components is a basic organic raw materials.Chemical degradation is closely related to degradation temperature, catalyst and degradation equipment.Generally speaking, there is an optimal degradation temperature point or temperature range for degradation, and catalysts are added in the cracking practice of most waste plastics. The catalysts are mainly silicon-aluminum compounds, as shown in table 1, which are also useful for other metal oxides, but few reports have been reported.Due to the poor thermal conductivity of plastics, after heating, it will become difficult to transport high viscosity melt and carbon will be generated in the high temperature decomposition of waste plastics on the reactor wall, resulting in emissions difficulties. Therefore, special degradation equipment is very necessary, among which groove, tube and fluidized bed reactors have been widely studied and applied.
Table 1 polyolefin thermal cracking catalyst types alumina catalyst commodity name, chromatographic separation of precious metals oxide with silica gel a Y zeolite, silica alumina, H - Y zeolite, alkaline oxides, 0. 2.1 Depolymerization (Depolymerization) is a plastic polymer degradation into monomer or other chemical raw materials, make its can be used for synthetic polymer, the technology of waste plastics are clean, additives, monomer purification is a key technology.Within the range of Hydrolysis and Hydrolysis, we'd like to talk about Hydrolysis and Hydrolysis.
2.2 thermal cracking (Pyrolysis) refers to the plastic under anaerobic conditions high temperature cracking (greater than 500 ° C).With German heavy oil company 10 t/d work device, for example, will be made by the mixed waste plastics recycling center in 699 ~ 800 ° C and heated to 1000 ° C for 30 min can be decomposed to 35% ~ 58% diesel and 23% ~ 40% of the gas.The study of university of petroleum of China points out that under the action of promoters, oil products and qualified compensation can be obtained by pyrolysis of waste polyethylene alone, the wax production rate is 50% ~90%, and the economic benefit of wax production is higher than that of oil production.Similar patents exist in the United States and Britain.
2.3 Hydrogenation is carried out at high pressure (hydrogen pressure around 30MPa) and low temperature (less than 500C) of hydrogen.The purity of pyrolysis products is lower than that of thermal pyrolysis products, which can be directly refined in refineries. Hydrolysis requires strict separation and crushing in advance and requires expensive equipment investment.The 2X 104t/a waste plastics treatment unit of v.o.agg company in Germany can decompose the mixed waste plastics into 80% liquid fuels and other products at 460~490C and 20MPa with hydrogen base as catalyst.2.4 Gasification refers to the degradation of waste plastics at a high temperature (up to 1500C). The products are CO and hydrogen, which can be used to prepare methanol and other related products.
Deutsch - ReifenNelHunststoffe thermal decomposition company and Salzgitter thermal decomposition company have been established in Germany for many years.
Table 2 has been industrialized production of biodegradable plastics profile foreign countries company main ingredients name of commodity production capacity (t/a) price ($/ kg) America starch a British Italian pva starch alloy in our country has put the light/microbial degradation plastic mulch "included in the national key scientific research projects, has made great progress, covering bare parts can be decomposed into a few months later under 4 CMX 4 cm pieces, on soil water movement, the soil capacity, heavy, pore, aggregate and compared three component content of heavy metals and other research results show that the damage to the soil are not,It has no effect on crop growth.Han changtai et al. made preliminary achievements in the study of non-starch controllable light and biodegradable plastic mulch.Agricultural films made from PLLA, a fully biodegradable plastic, have also been used.
At present, the quality of degradable plastic is not as good as that of ordinary plastic and the price is higher than that of ordinary plastic. At the same time, the nature of its natural degradation remains to be studied. In addition, the addition of other substances to degradable plastic is not conducive to the recycling of plastic.
Landfill is the worst way to dispose the waste plastic, but it needs the lowest cost. A landfill is a deep landfill that does not affect the growth of surface plants at least.Landfill as the final treatment of waste has certain characteristics: low cost of treatment;(2) the processing technology is relatively simple, which is conducive to popularization;Landfill can choose non-arable land as the site, such as: beaches, valleys, depressions, ditches, etc.;Even that doesn't require pretreatment of waste.In the process of landfill, anti-seepage treatment should be carried out for the landfill unit, and non-toxic and harmless covering materials should be used to cover the surface of garbage according to the specified technical requirements, and the collected leachate should be treated.On the basis of landfill, the waste plastics treatment facilities such as incinerator should be demonstrated and constructed step by step.
Can be seen from the above methods, the comprehensive utilization of waste plastics in addition to the direct recycling, more economical way is to use recycled, modification for the serious pollution and poor sorting of waste plastics or use thermal decomposition (recycled oil or produce the resin raw materials such as monomer intermediates) or by incineration (energy) finally adopt the method of landfill.
Plastic waste has a very wide range of applications, especially with the increasing attention to environmental pollution problems and the implementation of sustainable development strategy, the recycling and utilization of waste plastic will be more expanded, and produce great economic and social benefits, promote the in-depth research and development of relevant technologies in this field.
Zhangjiagang Brighter Machinery Co.,Ltd is a Chinese company ,located in Zhangjiagang city,Jiangsu Province , near shanghai pudong international airport . Brighter company focuses on researching and designing and manufacturing Series industrial shredders ,crushers for reducing size and recycling a variety of waste products , Plastic , Wood, Paper, Rubber , Light Metal Products , E-waste, Medical waste , MSW,RDF etc. Series high speed and low speed mixer for pvc compounding , Series pulverizers for making plastic flakes or granules into powder.