Metallurgy / Chemicals / Rubber & Plastics

According to the Huacheng Import and Export Data Observation Report, on January 5, China's environmental newspapers published the article "Can the development of the plastic industry" turn white into green "? Do a good job in carbon reduction and pollution control of plastics, high value utilization and waste into treasure is the best choice". Many interviewed experts affirmed the role of plastic chemical recovery method in carbon reduction and pollution control of plastics. Some experts pointed out that chemical recycling can eradicate plastic pollution.

So at present, what is the stage of chemical recovery in China and other countries? Can it be applied on a large scale? According to Huacheng Import and Export Data Observation, the chemical recovery of plastics, which is different from the simple energy recovery of incineration, is a method of converting low-value waste plastics into high-quality oil fuel or chemical raw materials. It is becoming the focus of scientific and technological research and development around the world, and is expected to become one of the main options to control plastic pollution, boost the circular economy, and achieve high-quality, safe and sustainable development.

1. Current situation of plastic recycling in China

China is a major producer and consumer of plastic products. With the increasing attention paid by the country to plastic pollution, the recovery rate of waste plastic products has gradually increased. In 2011, the recycling rate of waste plastics in China was less than 10%, reaching 23.09% by 2019, and 30% by 2020. It can be seen that the recycling market of waste plastics in China is growing steadily. By 2021, the overall recovery of waste plastics in China has reached 19 million tons, and the import of waste plastics will be cleared. However, at present, nearly 30% of plastics in China are still mixed in domestic garbage for landfilling, and there is still much room for improvement in the recycling of waste plastics in China.

At present, there are more than 10000 enterprises engaged in waste plastic recycling in China, but most of them are small and micro enterprises. There are few large-scale and group enterprises. The recycling chain is still incomplete, the recycling rate is not high, and the supply of recycled materials is unstable. However, on the whole, China's waste plastic recycling industry has formed an intensive recycling trading market and processing distribution center, and the entire industry is developing towards the direction of trading marketization and processing scale.

In recent years, with the economic and social development and the continuous improvement of people's living standards, plastics have been widely used due to their wide variety and excellent comprehensive performance. According to the observation report of Huacheng's import and export data, China's plastic products output has shown a fluctuating growth from 2017 to 2021, from 75.155 million tons to 80.04 million tons, with a small growth rate, of which the domestic plastic products fell significantly in 2018, It was 19.6% lower than that in 2017, which was mainly affected by the tightening of domestic environmental protection policies. With the increase of domestic consumption of plastic products, waste plastics will also grow day by day. In order to reduce the damage of waste plastics to the natural environment, the recycling industry has played a huge role.

From the perspective of waste plastic recycling, China's waste plastic recycling and recycling network covers a wide range and has a large scale. The amount of waste plastic recycling and recycling has gradually increased. During 2017-2019, the amount of waste plastic recycling in China has shown an upward trend. However, affected by the domestic epidemic outbreak in 2020, the amount of waste plastic recycling has decreased from 18.9 million tons in 2019 to 16 million tons in 2020, and gradually warmed up in 2021. The amount of waste plastic recycling has reached 19 million tons, Compared with 2020, it increased by 3 million tons, up 18.75% year on year.

2. Chemical recovery can reduce the new demand for fossil fuels

Waste plastics can be converted into high-quality oil fuel or chemical raw materials

According to the report released by the Recycled Plastics Branch of the China Material Recycling Association, the amount of waste plastics produced in China will be about 62 million tons in 2021. How to effectively deal with waste plastics is a major issue that China is trying to break. It is understood that at present, the effective treatment methods of waste plastics mainly include physical recovery and chemical recovery.

The main process of physical recovery of waste plastics includes collection, classification, crushing, cleaning, drying, granulation and production of corresponding products. It solves the problem of recycling relatively high value waste plastics that are easy to handle.

It is generally difficult to reach the quality of raw plastics by physical recovery, and its recycling is mostly degraded. In the treatment of low-value, mixed and contaminated plastic waste, this technology is difficult, economic and not applicable. Disposable packaging materials, such as various composite films and plastic bags, which are discarded and mixed with domestic waste, account for a large proportion of plastic waste. They are the "backbone" of plastic pollution control, and are also the urgent problems to be solved in the recycling and high-value utilization of plastic waste.

Chemical recovery refers to changing the molecular structure of plastics into liquid or gas low molecular or even monomer small molecules, which can be used to manufacture new petrochemical products such as plastics, thus reducing the new demand for fossil fuels and reducing the impact of the production of plastics on the environment. When the chemical recycling of waste plastics is for the purpose of fuel and raw materials, a closed cycle is formed, which is called the chemical cycle of waste plastics.

Chemical recovery of plastics is a method of converting waste plastics into high-quality oil fuel or chemical raw materials, which is becoming the focus of scientific and technological research and development worldwide. At present, there are mainly pyrolysis, gasification, depolymerization and other technologies, among which pyrolysis technology has attracted the attention of researchers.

3. The whole industrial chain model has attracted much attention

There are physical methods, chemical methods and energy conversion methods for recycling waste plastics. Physical recovery includes peer utilization and degraded utilization. The same level of utilization is dominated by modified regeneration, which improves the comprehensive performance of recycled plastics by adding auxiliary materials; Degraded utilization directly recycles waste plastics into plastic chips with lower quality.

At present, the physical recovery technology has been applied in China for many years and has been relatively mature. Enterprises pay more attention to how to develop the closed-loop system of the whole industrial chain.

Ding Peng, a professor at Shanghai University, said that in the whole waste plastic recycling system, there are five links: recycling system, raw material manufacturers, manufacturers, brands and consumers. The closed-loop system of the whole industrial chain is "plastic recycling - plastic recycled particles - PCR raw materials - recycling".

Industry insiders said that there are still many technical bottlenecks in China's renewable resources industry, such as extensive sorting in the recycling process, lack of refined sorting technology, and low mechanization and automation in the recycling process. A representative of the enterprises participating in the meeting told the reporter that there are roughly more than 100000 domestic renewable resources enterprises, which have been "small, scattered and disorderly" for a long time. Most enterprises have not invested a lot of money in the past. In the future, only those enterprises willing to invest in the use of excellent technology and equipment can realize the high-value recycling of plastics.

4. There are many types of waste plastics, and different technical schemes need to be adopted

All over the world are making technical breakthroughs in the treatment of waste plastics by chemical recycling, but they have not yet been applied on a large scale, especially in the aspect of the large-scale treatment capacity of the plant. Because there are many types of waste plastics, different technical schemes need to be adopted. The technology is very complex, and further research is needed.

General plastic packaging includes plastic products made of pure polyethylene and polypropylene, such as automobiles, home appliance accessories, etc. There is also a considerable part of composite packaging, such as plastic-plastic composite, aluminum-plastic composite, paper-plastic composite, etc., which contains a variety of plastic, paper or metal materials. This kind of plastic waste has high requirements for recycling and treatment technology, and requires joint research on process development and equipment manufacturing.

At present, the relevant tests of chemical recycling of plastics are being carried out, but the recycling system of low-value waste plastics in China still needs to be improved. How to collect and recycle low-value waste plastics and realize low-cost and efficient recycling is challenging and needs innovative exploration. The plastic components of plastic film residue are relatively single and large, and it is easy to be recycled in a centralized way. Sinopec has started with the recovery and utilization of plastic film residue, and is planning to build a 10000-ton industrial experimental device in Xinjiang.

According to the observation of Huacheng Import and Export Data, because Xinjiang is relatively dry, cotton fields, corn and other crops need to be covered with film to keep water and moisture. If all the anti-aging plastic film specified in the national standard is used, the cotton field alone needs nearly 300000 tons of plastic film every year. The residue of plastic film residue in the farmland affected the growth of cotton roots, resulting in the yield of cotton seed per mu decreased from 500 kg to 600 kg to about 300 kg to 400 kg now.

In order to solve this problem, Xinjiang governments at all levels encouraged farmers and farms to recycle plastic film residues and replace old ones with new ones by building residual film recycling stations and combining with relevant subsidy policies. According to the observation of Huacheng's import and export data, the recovery rate of plastic film in Xinjiang has reached 81% in 2021, and the pollution of cotton fields caused by the residual film of incremental plastic film has been effectively controlled.

After the plastic film residue is recycled and concentrated, and professionally sorted by partners, we will consider recycling it through chemical recovery technology and equipment. At present, this technology is relatively mature. It is believed that with the support of the government, social attention and the efforts of scientists, it is only a matter of time before the chemical recovery and large-scale utilization of low-value waste plastics in other fields in the future.