The hottest recycling to promote the harmony betwe

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Recycling promotes the harmony between plastic packaging materials and the environment (IV)

5 introduction to waste recycling methods

5.1 material recycling

after recycling packaging waste, it is used as raw material again to produce plastic products after classification, cleaning, drying and granulation. In recent years, the technology of this recycling method has made progress, and its use has also been expanded. The following projects have achieved good results

· in 2002, the cleaning Bureau of Hamburg, Germany, built a 4kt/a waste plastic recycling device, which received waste plastics mainly from HDPE detergent bottles from the recycling center, and used the separation technology of t · H company to produce aggregates for highway soundproof board building materials and imitation wood products. In addition to the 450 mark treatment fee charged from the recycling center per ton, the price of pellets per ton is 320 mark. Because the new product price is 1400 mark/t, it is very popular with users

· the recycling device of Austrian w · K · r company is 6kt/a. Waste plastics mainly composed of LDPE film are collected from the recycling center, and recycled pellets are produced for black plastic garbage bags made in Italy. A disposal fee of 1 mark is charged per kg, and the actual cost is 0.9 mark. Then it is sold at 0.35~0.45 mark per garbage bag, which has a good benefit

· France's michelonil company has the technology of crushing and impact separation by using the impact value difference between PVC and pet. With this technology and its related ethylene regeneration company, according to France's preferential policies for renewable resources, it invested 40million francs and built a 12kt/a production line 3. The company's waste plastic regeneration capacity is 25kt/A, In addition, French SIP company invested 78million francs to build a 5kt/a production line of recycled plastic boards with European standards

· the 2l coke can made of recycled PET by European Coca Cola company has been listed in Switzerland. Its structure is divided into three layers, with new materials on the inner and outer surfaces and recycled materials in the middle. Meiwilman used 100% recycled PET raw or inadvertently scraped the sheet metal to produce hot extruded containers, which are used for the packaging of wild vegetables and fruits

· Japan's nianran company and carpet fiber company have jointly developed the technology of crushing and melting PET bottles into polyester fibers. Toyo textile company has begun to use this technology to produce polyester staple fibers and textiles for clothing materials. Mitsubishi Corporation sells fabrics and ready-made clothes at home and abroad. Driven by them, 6 households including Toyo and Itochu Corporation also actively participate in the promotion

· Japan's Willow packaging industry and Mitsui petrochemical, takeno iron and other units have jointly developed the technology of making block stones from waste PET bottles. The PET bottle is crushed and made into pellets, which are melted at 280 ℃ and hot extruded φ 150mm block stone with a unit weight of 500g is used as road foundation. It is lighter than natural block stone, with good drainage and low voice. It not only replaces natural quarrying, but also reduces the waste volume to 1/20. At the same time, it is also a potential oil mine, which can be mined for oil refining in case of emergency

5.2 chemical recycling

there are three oiling technologies for the heating decomposition of mixed waste (except PVC, generally PE, PP, PS, pet, etc.): ① under anaerobic conditions, 50% of liquid fuel can be obtained by simple thermal decomposition at 650~850 ℃; ② After thermal decomposition at about 400 ℃, it is connected to the catalyst cabinet at 200 ℃ for contact thermal decomposition. Since the generated heavy oil is decomposed into light oil, the liquid fuel can reach 80%; ③ In 100~400atm high-pressure hydrogen, about 80% of liquid fuel can also be obtained by hydrogenation and decomposition with a variety of raw materials. It is hereby introduced as follows according to Japan and Europe and America

in Japan, more than 10 households carried out this research and development work in the 1990s, but only 1~2 households formed a scale. After the promulgation of the "law on the recycling and utilization of containment vessels", with the support of the Ministry of trade, industry and health, several development projects were carried out to focus on solving the problems of deaeration and cost reduction, which has reached the practical level, The key points are as follows:

· Fuji regeneration company invested 1.1 billion yen in the early 1990s with the cooperation of mobil oil to build a 5kt/a pilot plant in Xiangsheng workshop to conduct contact thermal decomposition tests on PE, PS, PP and other mixed waste plastics (excluding PVC and PET). Waste plastic is heated at -420 ℃ and decomposed into gas, and then sent to the contact reaction frame at 300 ℃. Under the action of ZSM-5 pumice catalyst, 1t PE can be decomposed into 800kg oil, 150kg propane gas and 50kg residue. After oil fractionation, 50% gasoline, 25% kerosene and 25% diesel oil are obtained

the small and medium-sized enterprise group announced that it would build a 50t/a pilot plant using the above technology, focusing on the oiling problem of PVC (~17%), pet and other mixed waste plastics. Electromechanical: the excellent electronic universal experimental motor adopts an exchange servo speed regulation system, that is, it is heated to about 300 ℃, and the generated hydrogen chloride is managed to be removed before thermal decomposition

Central Chemical Company recycled 475t of foamed plastics and other sundries from supermarkets by using Fuji renewable phase production plant, and mixed 60t of polyolefin for oiling test. 85% of naphtha and lpg10% can be recycled. Naphtha can be fractionated into steam, coal and diesel oil, and can also be directly used as power generation. Therefore, it is difficult to clamp these components as fuel. After the preliminary estimation reaches 5kt/a, the treatment fee is less than 50 yen/kg, so it is suggested that small and medium-sized cities can build devices with a scale of 0.3~0.6kt/a to generate electricity

· in order to meet the requirements of the "law on the recycling of packaging containers", with the support of the original province, Lichuan City, Tokyo, Nippon Steel, kubaoda and other units are responsible for investing 3billion yen to build a 10t/a pilot plant in Lichuan City, all using waste plastics such as Lichuan City, focusing on solving the problem of oily plastics containing impurities. In addition, the Association for the promotion of waste plastic treatment subsidized 400million yen to build a 6kt/a oiling unit (PVC accounts for 20%) in the plant of Lishi mineral oil company (Xintang county), a large lubricant producer, to treat the mixed waste plastics in the county

· environmental protection equipment factories have also developed oiling devices by themselves. For example, the industrial test device built by Hitachi shipbuilding in Ibaraki Prefecture adopts the contact catalytic decomposition method, which has basically passed the technical standard. However, the cost per L of fuel oil is 100 yen, which is three times the market price, making it difficult to be applied. According to this, Mitsubishi Heavy Industries cancelled the catalyst through precise control of decomposition temperature. Although the yield was slightly low, the cost was reduced by 50%. After appropriate improvement, it is expected to be practical

European countries also attach great importance to the oily treatment of waste plastics. All enterprises are carrying out experiments one after another, and classify and list several large-scale units as follows:

· thermal decomposition method

taking the l0t/a pilot plant of German heavy oil company as an example, the mixed waste plastics from the waste recycling center are heated at 600~800 ℃ and 1000 ℃ for 30 minutes, and can be decomposed into 35~58% diesel and 23~40% coal gas

· hydrogenation catalytic decomposition method

taking the 20kt/a waste plastic treatment unit of the German company as an example, the mixed waste plastic can be decomposed into 80% liquid fuel and others at 460~490 ℃ and 200bar with hydrogen and alkali as catalysts

· contact thermal decomposition

taking the industrial test device of BP chemical company in the UK as an example, LPG can be produced by heating the mixed waste plastics (80%pe, 15%ps, 3%pet, 2%pvc) in a fluidized bed at 450~500 ℃. The 28kg/h industrial test has been completed, and a 25kt/a production device is proposed

· BASF invested 40million marks to build a 15kt/a pilot plant for the treatment of waste plastics. First, the waste plastic is heated to 300 ℃ under isolated air, and the HCl produced by PVC is collected and used to produce hydrochloric acid. When it rises to 400 ℃, all kinds of oils and gas produced are directed to each workshop as raw materials for the production of PP and PE, accounting for 3~10% of the residue. It is planned to invest 350million marks to protect the construction to 300kt/A

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