Of mixed plastics waste

Section 3 discusses options for feedstock recycling of mixed plastic waste ... 

Concerning feedstock recycling of mixed plastic waste (MPW) with a low chlorine content, the following initiatives seem to be most promising. They are either operating in practice, have operated in the past, or have a fair chance of becoming operational in the short-term. Methods include ... 

The thermal cracking of a light ffaction of mixed plastics waste was carried out in a fluidised bed reactor and the fractions obtained were analysed by elemental analysis, gas chromatography and ashing. The main components of the waste were PE and PP with a small amount of PS and the bed was fluidised by pyrolysis gas, nitrogen or preheated steam. Experiments conducted at different temperatures and residence times were compared by calculating the crack severity for each experiment. The results obtained revealed that the amounts of ethene and propene obtained by pyrolysis with steam were comparable with those obtained using a commercial steam cracker. 

ENERGY RECOVERY THROUGH COMBINED INCINERATION OF MIXED PLASTICS WASTE AND SOLID MUNICIPAL WASTE... 

Polymer Degradation and Stability 53,No.2, 1996,p.l89-97 THERMAL DEGRADATION OF MIXED PLASTIC WASTE TO AROMATICS AND GAS... 

Feedstock recycling is examined as a method of plastics recovery. The range of techno logics currently employed are described, and include pyrolysis, hydrogenation, gasification, and chemolysis. Methods for the recycling of mixed plastics wastes are discussed, which include work by BP Chemicals, VEBA Oil, Shell Chemicals and Leunawerke. 

The use of mixed plastics waste as fuel for steel furnaces is briefly examined as NKK Corp., the second largest steelmaker in Japan plans to use about 66 million pounds of it. According to the company s test data, 440 pounds... 

Brussels, 1994, pp.8. 12ins. 24/3/95. 8(13)5 ENERGY RECOVERY THROUGH COCOMBUSTION OF MIXED PLASTICS WASTE AND MUNICIPAL SOLID WASTE... 

Davos, 14th-18th March 1994, paper 82. 8(13) MONOCOMBUSTION OF MIXED PLASTICS WASTE... 

Total costs may be reduced by charging gate fees for the acceptance of mixed plastic waste or municipal solid waste as feedstock or from the sale of treatment products such as the syngas or ammonium chloride (D19926C, p. 17 D199013, p. 3 D10958K, pp. 47, 51). 

Most polymer products are offered for recycling in the form of mixed plastic waste (MPW). Compressed gases as solvents may offer advantages compared with liquid solvents in the necessary separations (e.g., to collect families of polymers out of MPW) because such solvents are easy to recover and, furthermore, they make it possible to use pressure as an additional separation parameter or to remove the organic additives of the polymers. Finally, MPW may be added as a polymer solution in a compressed gas to a feed of a Naphtha cracker, and thus be recycled to base chemicals. 

Tall S (2000) Recycling of mixed plastic waste—Is separation worthwhile PhD Thesis, Royal Institute of Technology, Stockholm, Sweden... 

Association of Plastics Manufacturers in Europe, MSW Combustion-Effects of Mixed Plastics Waste addition on Solid Residues and Chlorinated Organic Compounds, APME, Brussels, 1994. 

W. Kaminsky, B. Schlesselmann and C. M. Simon, Thermal degradation of mixed plastic waste to aromatics and gas. Polymer Degradation and Stability, 53, 189-197 (1996). 

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. 

TECHNOLOGIES FOR TERTIARY RECYCLING OF MIXED PLASTIC WASTE (MPW)... 

This section deals with the economic evaluation of the conversion of mixed plastics waste (MPW) into synthetic crude (syncrude) oil and coprocessing of MWP with vacuum residue into syncrude. In their feasibility study, Ali and co-workers considered the process technology developed by Veba Oel AG of Germany the Veba Combi-Cracking (VCC) option for the processing of MPW [31], The process data and economic data were taken mainly from Dijkema and Stougie [32] and Huffman and Shah [33] for this study. All the cost data were translated to represent the economic analysis for Saudi Arabian conditions. 

G. P. J. Dijkema, and L. Stougie, Environment and Economic Analysis of the Veba Oel Option for the Processing of Mixed Plastic Waste , Interduct, Rotterdamseweg 145, 2628 AL Delft, The Netherlands (1990). 

W. Kaminsky and H. Sinn, Pyrolytic techniques, In Recycling and Recovery of Plastics, J. Brandrup et al. (eds), Hanser Publishers, New York, pp. 435-444, 1996. W. Kaminsky, B. Schiesselmann and C. M. Simon, Thermal degradation of mixed plastic waste to aromatics and gas, Polymer Degradation and Stability, 53, 189-197 (1996). 

J. Kim, W. Kaminsky and B. Schlesselmann, Pyrolysis of a fraction of mixed plastics wastes depleted in PVC, Journal of Analytical and Applied Pyrolysis, 40-41, 365-372 (1997). 

Some of the procedures of value for processing of mixed plastic wastes may also be useful for the recovery of value from the laminates used for efficient packaging of food and beverages (e.g., milk cartons, Tetrapaks). A combination of heat and pressure may be employed on a recycle stream of this type of material to fuse the mixed fibrous and resin components into a dense board-like product [31, 32]. This highly weather and insect resistant product, Eco Superwood Plastic Lumber, may be sawn, nailed, drilled, etc., like wood, and it resists rotting in direct contact with the soil without the need for preservatives. 

The main constraints for improving mechanical recycling rates are the imbalance between the collectable waste and the potential end-markets for recycled resins, and the presence of large quantities of mixed plastic wastes which are difficult to clean and sort. 

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