Chemical recycling, technology

Chemical recycling of waste mbbers means breaking down of the macromolecules into oligomers or monomers. Different chemical recycling technologies include glycolysis, methanolysis, and... 

ICI Polyurethanes is working on development of a split-phase glycolysis chemical recycling technology for polyurethane, and plans to build a full-scale plant in Britain to recycle polyurethane foam from mattresses, furniture, and automotive seat cushioning. 

Other than for incineration and some of the newer chemical recycling technologies, sorting of plastic waste into polymer types is of fundamental importance. In order to make separation easier for the consumer an international plastic recycle code mark is printed on larger items (Table 2.3). Even small amounts of a mixed plastic (sometimes as low as 1%) can have significant detrimental effects on the properties of a recycled polymer and result in it needing to be used in low-value applications. 

The difference between chemical and feedstock recycling is pecuhar. As we will see in the next sections, there is, in essence, hardly any technology that recycles polymers into its own monomers. In this report we will concentrate on feedstock recycling, but in this broad definition we will include chemical recycling as well, see Section 5. 

This whole picture suggests that chemical recycling is financially still a rather uncertain business, a view that is indeed reinforced by cost calculations. The basic point probably is that purpose-built recovery installations will always have trouble in competing with technologies built for another purpose, but which happen to be able to recycle or recover MPW - which is the case with blast furnaces and cement kilns. The latter have the advantage that capital investment does not need to be allocated to the MPW. 

The reaction-catalysing properties of super-critical fluids are described, and some examples are demonstrated of the chemical recycling of waste plastics. 16 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. 

Progress in Rubber and Plastics Technology 16, No.l, March 2000, p.61-8 CHEMICAL RECYCLING OF WASTE SATURATED POLYESTERS AND URETHANE POLYMERS TO YIELD RAW MATERIALS FOR THE PRODUCTION OF POLYURETHANES Kacperski M Spychaj T Szczecin,Polytechnic... 

Advances in Polymer Technology 14, No.4, Winter 1995, p.337-44 CHEMICAL RECYCLING OF MIXED PLASTICS BY PYROLYSIS... 

Details are given of a visit by RECOUP to BP Chemical s feedstock recycling demonstration unit in Sunbury. The feedstock recycling technology has been developed by a consortium of companies, and will enable polyolefin rich plastic waste from domestic and commercial sources to be vapourised and then condensed to form a hydrocarbon wax. This can then be used to feed existing petrochemical crackers to produce polymers indistinguishable from virgin material, it is claimed. 

Three recycling news items are very briefly reported upon a Canadian-developed pyrolysis technology that converts plastics scrap into alpha-olefins, a scrap-plastics-to-monomers system under construction in Scotland, and statistical forecasts on chemical recycling in Germany for 1996. 

In examining the technical options for plastic waste management, chemical recycling appears to be the least developed and most difficult. In this paper, BP Chemicals sets out its analysis of the factors that will determine the choice of chemical recycling process technology. From this a process concept based on thermal cracking is developed and the hurdles to be overcome before such a process can be realised is discussed. 

Proponents of a technology that converts plastics into chemical feedstocks for use as new resin or fuel, are optimistic that it will eventually be accepted as recycling. The technologies and targets vary, but, according to representatives, the conversion of plastics into feedstocks is a feasible recycling technology for wastes that do not... 

The trends in environmental research will be considered on the basis of polymers, fillers, oil, and other processing aids, reinforcing fabrics, other chemicals, and recycling technology. Broadly speaking, the following research trends are evident on a global scale ... 

Various treatment technologies are used at the iron and steel plant for recycle system water treatment prior to recycle and reuse, or end-of-pipe wastewater treatment prior to discharge to surface water or a POTW. The physical/chemical treatment technologies extensively used include equalization, tar removal, free and fixed ammonia stripping, cooling technologies, cyanide treatment technologies,... 

Eastman Chemical Company, MBC-231, Optisys Polyester Recycling Technology, Eastman Chemical Company, Kingsport, TN, 1999. 

Feedstock or chemical recycling is seen as complimentary to mechanical recycling and seems appropriate for cost effective treatment of mixed and contaminated plastic waste streams (115). A progress report, on potential technologies for high PVC content mixed plastic waste streams, is available (21). Promising developments, which look technically and economically viable, are ... 

A. Tukker, Plastic Waste - Feedstock Recycling, Chemical Recycling and Incineration, Vol 13(4), RAPRA Technology Ltd., 2002. 

The quality of the product is of primary importance in developing a recycling technology converting plastics into fuels by pyrolysis. Today the characterization of a liquid fuel from any sources is obviously based on the qualification methods and standards of fuels from mineral oil. The properties of the pyrolysis-derived fuels from plastics are expected to be similar to conventional fuels (energy content, viscosity, density, octane and cetane number, flash-point, etc.). However, in addition to the familiar ranking values it is necessary to know more about the chemical composition of the plastic pyrolysis oil, because of the peculiarities as follows ... 

Thus, for the development of polymer waste recycling technologies it is helpful to be aware of the chemical composition of the pyrolysis products of those polymers which are typical components of plastic wastes. 

G. Mackey, A review of advanced recycling technology, American Chemical Society Symposium, 609, Chapter 14 (1995). 

A. Homung, S. Donner, W. Koch, J. Schoner and H. Seifert, Haloclean/Pydra -thermal-chemical recycling of WEEE, Workshop Environmentally Clean Technologies for Sustainable Production and Consumption, Vancouver, CDN, 27-29, August 2003. 

The 1973 petroleum crisis intensified research on coal liquefaction and conversion processes. The technology developed in this field was later harnessed in chemical recycling of plastics. Mastral et al. [32], for example, employed two different batch reaction systems (tubing bomb reactors and magnetically stirred autoclave) and a continuous reactor (swept fixed bed reactor). Chemical recycling techniques such as pyrolysis [28, 33-38] or coliquefaction with coal [39, 40] convert plastic wastes into hydrocarbons that are valuable industrial raw materials. 

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