Plasticizer fraction

Before MPW is fed into the process, a basic separation of the non-plastic fraction and size reduction is needed. This prepared feedstock is then introduced in the heated fluidised bed reactor which forms the core of the process. The reactor operates at approximately 500 °C in the absence of air. At this temperature, thermal cracking of the plastics occurs. The resulting hydrocarbons vapourise and leave the bed with the fluidising gas. Solid particles, mainly impurities formed from, e.g., stabilisers in plastics, as well as some coke formed in the process mainly accumulate in the bed. Another fraction is blown out with the hot gas and captured in a cyclone. 

The liquefied plastic fraction is heated to over 400 °C. This leads to cracking of the plastic into components of different chain lengths. Gases count for 20%-30% and oils for 60%-70% they are separated by distillation. Any naphtha produced is treated in a steam cracker, resulting in monomers like ethylene and propylene that are recovered. Such monomers can be used to produce plastics again. The heavy fractions can be processed into synthesis gas or conversion coke and then be transferred for further use. At most 5% of the input is converted into a mineral fraction. It is likely that this consists mainly of the inorganic additives in plastics. 

From the description above it already can be deduced that this plant can deal with a lot of waste types and hence is rather robust in terms of acceptance criteria. S VZ has experience with treating mixed plastics waste, waste derived fuel (a mixture of plastics, wood and paper), the shredder light fraction of car wrecks, and the plastic fraction from shredded white goods and electronics. SVZ can handle on average 2% chlorine in MPW, with short-term excursions to 6%. The overall chlorine content has to be controlled by a right blend with other waste types. SVZ does not favour a high... 

An Ecoprofile is an assessment of the environmental and resource impacts of a waste disposal process. This paper describes ecoprofiles for six different ways of disposing the plastic fraction in municipal solid waste -two material recycling processes that include separation of the plastic waste, material recycling without separation of the plastic waste, pyrolysis, incineration with heat recovery, and landfill. 17 refs. 

The objectives for disposal of electronic waste appliances are (a) stripping of hazardous substances (b) reduction of pollutant and metal contents in the plastic fraction, thus permitting recycling or incineration in waste incineration plants or cement works (c) recovery of nonferrous metals and (d) attainment of commercially recyclable scrap quality. 

The effective density of separation depends on the particle size and aspect ratio. As the particle size and aspect ratio decreases, the separation becomes more efficient and the offset between separation density and hydrocyclone medium density decreases. This findings suggest that for efficient density separation closely sized fine plastic fractions are required. 

Oyanagi,Y., Ferry, J.D. Viscoelastic properties of polyvinyl acetates. IV. Creep studies of plasticized fractions. J. Colloid Sci. 21, 547-559 (1966). 

Still, the demand for recycled plastics is low, mainly due to a general uncertainty of the quality of the recycled material. The possibility of offering high quality recycled polymeric materials relays on a reliable and selective collection and sorting, an efficient recycling process and of course an available end-market. The basic technological development, thus, lies in the development of fast, reliable and relatively cheap methods for characterisation of separated and commingled plastic fractions. Recently, it was demonstrated that separation, at home, of a very small amount of products can mean a decreased use of raw oil and less emission of CO2 to the environment [11]. If... 

Waste from electrical and electronic equipment arises at the sorting plant, where the frame, the printed circuit board PCB, the cathode ray tube, etc. are separated for recycling. The remaining plastics fraction is in part flame-retarded, hence contains brominated and antimony compounds. The number of WEEE recycling plants is growing, so that the logistics are no longer a major problem. 

Another approach for overcoming the problems posed by conventional cracking catalysts has been disclosed recently by Reverse et al. [101]. In this case, direct cracking is performed by using as catalyst a molten bed of pure metal or a metal mixture (mainly lead, zinc, tin) at a temperature of 460-550°C wherein the waste polymer is loaded inside the reactor at a certain depth. The authors point out that the products are indeed a result of the combination of both thermal and catalytic cracking. The catalyst composition may also include some acidic component such as metal silicates, metal carbonates and their mixtures. The process can be applied to pure and mixed polymers (PE, PET, PP, PVC), as well as to the plastic fraction of municipal solid wastes. 

To recover a maximum of olefins and butadiene from recycling polyolefins, it is necessary to have a short residence time of the product gases in the fluidized bed zone to avoid no secondary reactions. The pyrolysis gas should not be circulated and used as fluidizing gas. For the experiments, steam was used as fluidizing gas [13, 14]. An easy separation of the hydrocarbon products is possible by condensation to water in a cooler. The results are shown in Table 17.6. As feedstock a light plastic fraction from household waste separation was used which contains 95.8% of PE and PP, 3% of PS, and 0.2% of PVC. 

These results prove that pyrolysis is an adequate process to reprocess pure plastic materials as well as contaminated plastic fractions of household waste. 

The described example of solution analysis was shown for the analysis of crude oil vacuum residue, but this method can be successfully applied for different kinds of feed. In our investigation, we used this method for the analysis of mixtures of vacuum residue and plastics, and pure plastics. In the case of the plastic or product of its cracking analysis, one has to consider that what is left behind after soxhlet extraction is the heavy plastic fraction or non-cracked plastic. 

The first major battery-breaking step is the dismantling or breaking of the battery to gain access to the lead units. There are numerous ways to do this, but the most common approach is via a hammer mill or roller crushers. The fragmented product is fed to a sink/float or hydrodynamic separator where the fractions are sorted. In the basic sink/float cell, the plastic fractions are floated off and removed to the plastics recovery section whilst the lead-bearing portions of metallics and compounds sink to the bottom and are removed via conveyors or other means, for further... 

All PE plastics-fractional melt (melt index 0.4-1.0 g/10 min at 190°C/2.16 kg). The hgures below are minimum requirements. 

The drawbacks of the manual platforms— which range from high labor cost to the complexity of labor management—may be avoided by resorting to automatic platforms. The machines required for such automation are manifold and the necessity to employ them is related to the quality of the collected material. Essential machines are rotary screen, light-parts separation equipment, heavy-parts separation equipment, and aluminum rejection equipment. All such machines are preliminary to the stage of separation into homogeneous plastic fraction. 

An alternative approach to the recovery of automotive plastics is therefore to use them as large, easily removable components that offer potential for reclamation as well-characterized individual polymers. Some particularly complex components such as vehicle front- and rear-end systems, exhibit special suitability for manufacture in plastics instead of metals because of their ease of production and assembly. It is generally recognized that improvements in automotive scrapyard economics may be best achieved by the prior removal from vehicles of such large polymeric components and their recycling as well-characterized plastic fractions. For example, plastic fuel tanks of HOPE are now in common use and represent the most common recyclable plastic component. Trials with material recovered from used plastic fuel tanks have shown promising results for the manufacture of new tanks [6]. 

The glass transition temperature of plasticized compositions is a function of the plasticizer fraction in the system. However, this effect occurs only when there is complete thermodynamic compatibility. In heterogeneous systems the plasticized composition shows two glass transition temperatures, Tg, an indication of the presence of two phases. The Tg of the polymer phase does not vary with change in plasticizer concentration. This effect has long been known for plastics and mbbers. 

Note that all of the above eqnations assnme that the polymer-plasticizer system is a single-phase system in a whole range of concentrations. If the compatibility is limited, it is necessary to expect that, at the plasticizer concentration greater than the compatibility limit, the glass transition temperatnre of polymer phase may not vaiy on inctease of plasticizer fraction." That is the concentration dependence of ATg can be described by one of the eqnations (10.13-10.22, 10.24-10.26) only np to the compatibility limit. Outside the compatibihty hmit the glass transition temperature is nearly constant (see Figure 10.34, curve 2). This corresponds to Kanig s inconsistency discussed above. In the case of the weak compatibility these equations may be used only within rather narrow intervals of plasticizer concentrations. 

Figure 16.1 shows that unoccupied volume increases with increase in plasticizer fraction. Figure 16.2 shows that the diffusion coefficient of oxygen also increases with plasticizer fraction. 

The distillate obtained in the condensation device can either be worked-up in a further step of the novel process or used as a fuel for firing the burner (2). The plasticizer component obtained on thermolysis contained 3.3% of organically bound chlorine and <0.3% of chloride. Analysis by gas chiomatograply and mass spectrometry showed that the brown oil comprised mostly of di-(2-ethylhexyl) phthalate. In addition, significant amounts of chlorooctanes were present. The distillation of condensate yielded 63.3 wt% of the plasticizer. Fractional distillation was conducted at a pressure of 1 to 5 mbar. ... 

The plastic fraction used in WPC is usually recycled PE, PP, PET, PVC PS, or a mix of these. Wood fiber as well as other natural lignoceUulosic fibers can be used as the filler the characteristics of fibers that are good candidates are shown in Table 5.9. Being of natural origin, a given type of fiber can have a large variation in properties (Kouini and Serier, 2012). The use of compatibilizers or pretreatment of the wood fraction is often employed to ensure good dispersion of filler in the plastic matrix. 

Plastic waste is classified into several subcategories in the USEPA compilation and the fraction of specific resins in each, identified. It is instmctive to study the data (despite their limited reliability) to identify which types of plastics are prevalent in the MSW stream. Table 9.1 shows that four resins (low density polyethylene (LDPE), polypropylene (PP), HDPE, and PET) dominate the plastics fraction in the MSW. Of these, the PET and HDPE are recycled to a significant extent (at 28% and 6% respectively). Majority of the plastic wastes however is landfiUed. The United States lags behind European countries such as Sweden, Austria, Belgium, and Germany as well as Japan in plastics waste recovery. 

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