Total recycling of CCA treated wood waste by low-temperature pyrolysis
- Katholieke Univ. Leuven, Heverlee (Belgium). Dept. of Mechanical Engineering
- Beaumartin S.A., Gradignan (France)
A system to turn a potentially harmful stream of solid waste into a set of substreams with either commercial value or highly concentrated residual streams is presented. The waste which is considered is metal impregnated (in particular Chromated Copper Arsenate (CCA) treated) wood waste and timber, such as telephone poles, railway sleepers, timber from landscape and cooling towers, wooden silos, hpo-poles, cable drums and wooden playground equipment. These waste streams sum up to several 100,000 tons of material per year currently to be dumped in every major country of the european Community (EC). Technologies need to be developed to reduce this CCA treated wood waste, such that all of the metals are contained in a marketable product stream, and the pyrolysis gases and/or pyrolysis liquid are used to their maximum potential with respect to energy recuperation. Pyrolyzing the CCA treated wood waste may be a good solution to the growing disposal problem since low temperatures and no oxidizing agents are used, which result in lower loss of metals compared to combustion. An experimental labscale pyrolysis system has been developed to study the influence of the pyrolysis temperature and the duration of the pyrolysis process on the release of metals and the mass reduction. The macrodistribution and microdistribution of the metals in the solid pyrolysis residue is studied using Inductively coupled Plasma mass Spectrometry (ICP-MS) and Scanning Electron Microscopy coupled with Energy Dispersive X-ray Analysis (SEM-EDXA). Furthermore, a complete mass balance is calculated over the pyrolysis system. Based on these results a semi-industrial pyrolysis system has been developed consisting of three stages: grinding, packed bed pyrolysis and metal separation. Special types of equipment have been developed to carry out the three stages. A new grinding system has been developed, based on a crushing mechanism rather than a cutting mechanism.
- OSTI ID:
- 347645
- Report Number(s):
- CONF-980513-; ISSN 0956-053X; TRN: IM9923%%182
- Journal Information:
- Waste Management, Vol. 18, Issue 6-8; Conference: International conference on incineration and thermal treatment technologies, Salt Lake City, UT (United States), 11-15 May 1998; Other Information: PBD: 1998
- Country of Publication:
- United States
- Language:
- English
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