Green Packaging: Environmental Issues for PVC (V)

PVC has a negative effect on the recycling of other plastics in mixed plastic waste. When PVC is treated with other plastics, for example in the packaging waste stream. The processing temperature is limited to the range of PVC treatment, which is relatively small compared to other plastics. Due to the similar density, polyethylene terephthalate (PET) and PVC wastes are difficult to separate, and the presence of PVC imposes additional costs on some PET recycling agencies, such as PET bottles. In some cases, the PVC industry has realized this issue and funded this additional cost. 

Like other materials, PVC recycling is also limited by the overall cost of recycling. When the net recovery cost (ie the overall cost of collection, separation and disposal minus the sale income of the recovery agent) is lower than the price required for other waste management approaches for the relevant PVC waste, economic gains can be achieved. If economic gains are not achieved, recycling of PVC waste under free market conditions will not occur unless there is a legal obligation or voluntary means to force or promote the recovery of PVC. Considering the availability and cost of waste, the collection is mainly a bottleneck. 

High-quality recycling of post-consumer waste (especially pipes, profiles, and flooring materials) is currently not profitable because the cost of net recovery is just above the cost of landfill or incineration. In addition. Separating waste at construction sites requires higher costs for waste owners.低 Low-quality recovery of post-consumer waste, such as packaging waste, is not economically profitable. Other waste streams that are suitable for low-quality recycling cannot be economically profitable, such as office supplies and printing film. Due to the presence of valuable metals. For example, copper, cable insulation is the only post-consumer waste that can be recycled at competitive costs. 

All in all, the recovery of pre-consumer waste can in principle be profitable. However, the recycling of post-consumer PVC waste is far from being economically competitive. In addition to establishing a recycling mechanism covering a wider area, financial incentives are necessary to collect PVC waste separately. Also, PVC is always present as an integral part of synthetic materials or mixed polluted waste streams that require special collection and sorting operations. The price of the raw material with a large variability (between 0  5 and 0  8 €/kg) has a great influence on the profitability of recycling. In addition, the price of landfill and incineration is relatively low. However, it can be expected that economic conditions for recycling will likely improve in the coming years, especially as the cost of landfill and incineration increases. 

Future developments and policy trends

In the basic plan, nearly 9% of the total PVC waste can be mechanically recovered in 2010 and 2020, representing 400,000 tons of PVC waste in 2010 and 550,000 tons of waste in 2020. The recovery rate varies depending on the particular waste stream considered. 

• For high-quality recycling, the following recovery rates can be achieved for construction and waste PVC waste: about 25% of the pipeline, about 40% of the window frame, and about 12% of the floor material. 

• For low-quality recycling, the recovery rate of cables that exist in the waste streams of buildings and rubble can reach about 65%, about 30% from power electronics, and about 20% from packaging. 

• Other waste streams, such as domestic and commercial wastes, cannot be recycled according to the scenario. 

Compare the basic plan and estimate the maximum recovery capacity. It represents the amount of PVC that can be recycled and takes into account the technical and economic limitations of PVC recycling. Based on this assumption, the recovery of post-consumer waste will reach 800,000 tons in 2010 and 1.2 million tons in 2020, representing a recovery rate of nearly 18%. This means that the mechanical recycling of PVC waste can only be one fifth of the post-consumer waste of PVC. Other waste management approaches will therefore remain important. 

In the March 2000 agreement, the PVC industry has made quantitative commitments based on mechanical recycling of pipes, fittings and window frames. For the pipeline, we promise to "at least 50% of the recoverable amount of waste from pipelines and equipment before 2005." For window frames, promise "at least 50% of the amount of collected window frame waste can be collected before 2005." These goals are not based on the generation of waste, but on the collection of waste. 

According to the PVC industry, the estimated annual recycling volume in 2005 is as follows: 15,000 tons of pipelines and 15,000 tons of window frames. However, the following large amounts of PVC waste streams that can be used for high quality recycling are not included in the agreement: rigid profiles other than window frames (around 240,000 tons in 2005), decorative floors (240,000 in 2005) About tons), flexible profile and hose (about 120,000 tons in 2005). However, in the agreement, the PVC industry has shown that in other possible applications, such as PVC cables, flooring and roofing films, "more work is needed to develop appropriate logistics, technology, and reuse applications." In addition, the industry has promised that it will “support as soon as possible” the development including the realization of higher mechanical recycling targets. 

4.3 Chemical Recovery

There are several processes that are chemical recovery, in which the polymers that make up the plastic are broken into smaller molecules. These small molecules are either monomeric molecules that can be directly used to produce new macromolecules; or they can be used as basic raw materials in the chemical industry. 

For PVC, in addition to the breaking of the polymer chain, the chlorine atoms attached to the chain are also released in the form of HCI. HCI is either reused after purification, or it must be neutralized to form different products, some can be reused, and some must be disposed of, depending on the technology used in the process. 

In the past five years of practice, only a limited number of initiatives have been taken. These initiatives have led to the establishment of some factories and the need to build such factories in the near future. The chemical recovery process can be classified according to whether they can recover high chlorine content or low chlorine content. For those processes classified as low chlorine content, the maximum chlorine content in PVC is 4%-5%. In the past, three factories that chemically recover low-chlorine wastes have closed down for economic and supply problems. For high chlorine content wastes, there is now an operational process based on incineration technology plus HCI recovery. Two pilot plants that have been built in the coming years will be put into operation. 

According to some assessments of the life cycle (LCH), some chemical recycling processes will be better than municipal solid waste incineration and landfill processes in terms of energy use and prevention of global warming. In addition, chlorine can be recovered in some processes, thus avoiding new products of ionized chlorine. Available assessments do not allow the selection of any of the chemical recovery technologies that have been analyzed. Direct mechanical recovery of wastes with high PVC content is a good environment-friendly process, especially considering the recovery of high-quality waste, and it does not include waste separation and pretreatment. 

From an economic point of view, it seems that chemical recovery of high levels of PVC waste is not attractive. In those areas, mechanical recycling has proven its technical feasibility in addition to flooring materials. This means that treatment plants that chemically recycle high levels of PVC waste will have to focus on those areas where mechanical recycling is not feasible, and those that contain excessive impurities because of additional separation steps, or other limitations related to environmental issues. Instead of mechanical recovery of various types of waste. 

In EU countries, the chemical recovery process is mainly competing with waste disposal processes such as landfills and incinerators. Landfills and incineration methods have the lowest entry fees. Purpose-built chemical recovery plants will also face competition from the operation of blast furnaces and cement kilns, which can absorb a large amount of mixed plastic waste with limited PVC content. 

When considering different kinds of waste, it can be seen that in the current waste separation form (such as agricultural waste, industrial waste and non-packaged household waste), although chemical recovery is technically feasible, it still faces a lack of legislation, Lack of competition for operating equipment. For automotive and e-waste, the content of PVC in the mixed plastic waste seems to be so high that it is not suitable for recovery by recycling low-chlorine content mixed plastic waste: but the PVC content inside this seems to be so low that it is It is not economically suitable to use the method of separation and reprocessing first. 

In general, it can be concluded that the success of a chemical recovery plant is based primarily on economics. There are still very important issues at this stage. They obscure the feasibility of operating these factories. 

Future developments and policy trends

Chemical recovery can be used as a potential method when it is not possible to choose a mechanical process to recover waste, especially when policies are favorable and equipment is available. These facilities can compete for cost-effective recycling processes. 

In 2010, the total amount of PVC waste that can be chemically recovered in the basic plan is: 80,000 tons of mixed low-chlorine waste plastics and 160,000 tons of high-chlorine waste plastics, mainly from automotive waste, electronic waste, and power waste. 

The industrial sector has a responsibility to invest 3 million euros in 2001 to establish a pilot plant to recover chlorine and hydrocarbons from PVC-packed materials. The results of this pilot plant can be obtained in mid-2002, so that it can make a decision whether to invest in commercial operations. (to be continued)