Commingled plastics

The thermal degradation of mixtures of the common automotive plastics polypropylene, ABS, PVC, and polyurethane can produce low molecular weight chemicals (57). Composition of the blend affected reaction rates. Sequential thermolysis and gasification of commingled plastics found in other waste streams to produce a syngas containing primarily carbon monoxide and hydrogen has been reported (58). 

In 1993, over 41 million pounds of polystyrene was recycled into new plastics products in the U.S. (77). Eor commingled plastics, gasification comes closest to competing with low cost landfilling (57). 

It is not tme either that vinyl is the problem in municipal recycling because it contaminates other resins. Contamination occurs whether or not vinyl is present. Other resins are just as much a contamination problem as vinyl. Except for commingled plastics apphcations, different plastic materials caimot be mixed successfiJly in most recycled products apphcations. This is why it is cmcial to separate efficientiy one plastic from another. Because of the chlorine that is present in it, vinyl lends itself very weU to automated sorting technology. 

Commercial tellurium, 24 408, 414 Commercial vaccines, 25 487 Commercial waste, 25 864 Commingled plastic wastes recycling, 21 453-456 thermal cracking of, 21 454 thermal degradation of, 21 454 Commingled recyclables, 21 368 in waste collection, 25 869-870 Comminution, 16 135... 

Mixed, or commingled, plastics must be dealt with differently to find end uses. Several technologies exist for mixed plastics, such as the ET/1 extrusion process from Advanced Recycling Technology of Belgium and a compression-molding process from Recycloplast of West Germany. At... 

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... 

VACUUM PYROLYSIS OF COMMINGLED PLASTICS CONTAINING PVC. PART II. PRODUCT ANALYSIS... 

R. Miranda, J. Yang, C. Roy and C. Vasile, Vacnnm pyrolysis of commingled plastics containing PVC 1. Kinetic stndy. Polymer Degradation and Stability, 72, 469-491 (2001). 

Pyrolysis recycling of mixed waste plastics into generator and transportation fuels is seen by many as the answer for deriving value from unwashed, commingled plastics as well as managing their desired diversion from landfill. 

PVC in the feedstock stream in limited amounts can thus be tolerated if a HCl removal process based on calcium hydroxide (slaked lime) injection is used. This is essentially a form of in scrubbing in the pyrolysis reactor itself. This method is used by a number of pyrolysis processes since the fuel oil end products need to be low in chlorine to minimize engine corrosion problems. In the pyrolysis of commingled plastics, lime can be added to the input material and the PVC content reduced down to 2-3% in order to avoid deposits of CaCl2 in pipework. The chlorine content of the final diesel should not exceed 10 ppm. 

The heterogeneous commingled plastics waste is converted into a homogeneous liquid or granulated at the exit of the extruder or heated up so much at the end of the extruder... 

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