Mixed plastics waste composition

Two types of approach exist to study the behaviour of plastic mixtures during pyrolysis. On one hand, some authors [46] work on plastic waste mixtures while other authors [47] work on simulated mixed plastic waste prepared with a specific composition. The proportions of the different polymers are based on mean values related to real waste mixtures. 

The detailed analysis of the derived oil/wax and gas products from the pyrolysis of plastics in relation to process conditions and different types of plastic is essential in providing data for the assessment of the feedstock recycling process. In addition, the yields and composition of gases and oils from the pyrolysis of mixed plastic waste are important in assessment of the process and to determine the possibility of any interactions between the plastics during pyrolysis. 

A real plastic waste collected by the German Dual System (DSD) from municipal packaging waste was pyrolyzed in the laboratory plant as well as in the pilot plant. The composition of the mixed plastic wastes is shown in Table 17.4. 

Table 17.4 Different compositions (A and B) of the mixed plastic wastes nsed in wt% collected by the DSD system...

Table 19.2 Feed composition of mixed plastic waste [8]. (Reproduced with permission from Elsevier)...

Many carpet manufacturers, fiber and chemical suppliers, recycling companies, and academic institutions are actively pursuing various methods to recycle fibrous waste. The approaches include chemical processes to depolymerize nylon and other polymers, recovery of plastic resins from carpet fibers, direct extrusion of mixed carpet waste, composites as wood substitutes, fibers for concrete and soil reinforcement, waste-to-energy conversion, and carpet as feedstock for cement kilns. 

An interesting way to manage mixed plastic waste is to use it as matrix for composite materials. In this way it is possible to reinforce the otherwise poor secondary material with the potential side advantage of reducing the overall environmental impact by using natural fillers or fibers that can also be chemically... 

Tipco Industries Ltd., in Bombay, India, produces Tip wood, a composite material from mixed plastic waste and 20% filler for use as a wood substitute for applications such as pallets, benches, fencing, and road markers. 1 ... 

Mixed plastic waste, e.g., from household, consisting of a variety of compositions comprising polyolefins, PVC, PS, polycondensates (viz. PA, PC, PET), etc. 

Camacho, W. and S. Karlsson, NIR, DSC, and FTIR as Quantitative Methods for Compositional Analysis of Blends of Polymers Obtained from Recycled Mixed Plastic Waste. Polym. Eng. ScL, 2001. 41 1626-1635. 

Additives often form a problem in recycling processes. Material recycling is often not possible or only with a considerable loss of quality. Plastics recycling is notoriously difficult due to the mixed composition of the plastics waste stream. The recycled material can only be used in certain applications that do not demand a pure material. Recycling of the additives themselves is theoretically possible only for metals, but in practice this type of recycling is not feasible. The metals occur only in low concentrations. Recovery from fly ash and bottom ash is possible, but expensive in view of growing scarcity problems it may become a viable options for at least some metals. 

Energy production and consumption pose nature into pressure and make the energy sector becomes the largest contributor of greenhouse gas (GHG) emission in Vietnam since 2010, accounting for 67%. Several emission sources of GHG could be found in a waste treatment facilities it came from (1) emission of methane (CH4, GWP 25) at landfill of mixed waste, (2) from emission of fossil carbon dioxide through the combustion of plastics and composites or supported fuels (auxiliary), and (3) from emission of nitrous oxide (NOx) during incineration/ pretreatment process, etc. 

Plastics waste arises at the levels of production, conversion, and consumption. In the first two categories source separation, identification, and recycling, is straightforward. Such simple source separation concepts no longer hold for post-consumer recycling, where entropy is immense plastic products both geographically and functionally are widely spread, more often than not compounded with unknown additives, or mixed, soiled, composite, and difficult to collect at a reasonable cost. 

In addition, the presence additional chlorinated compounds in the PET mixed plastics such as 3P/PVC/PET and MWP were found to be chlorine derivatives of benzoic acids. Kulesza and German [36] reported the influence of poly(vinyl chloride) on poly(ethylene terephthalate) pyrolysis. They reported that the chloroesters of terephthalic and benzoic acids were found with PVC and PET mixtures (1 1). In our present investigation, the PVC/PET ratio was 1 1 and contains the other plastics such as PE, PP and PS. The ratio of mixed plastics PP PE PS PVC PET was 3 3 3 1 1 and this composition was prepared are similar to the real municipal waste from Sapporo, Japan. 2-Methyl benzoylchloride was identified as one of the additional chlorinated hydrocarbons observed in 3P/PVC/PET and MWP degradation than 3P/PVC degradation chlorinated hydrocarbons. The other chlorinated hydrocarbons could not be identified in 3P/PVC/PET and MWP degradation. It is evident from the studies that the new chlorine compounds obtained due to the presence of PET in plastic samples in either model mixed on MWP. 

Input material for the production process is dirty, mixed plastic material from private households. One of the main tasks of the production process is to prepare hard plastics (e. g. HD-PE, PS, PVC-U and PET) as well as foils (LD-PE) which are difficult to handle in milling processes. The composition of the waste material differs in a wide range, main parts are the polyolefines. 

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