Pyrolysis of Furniture and Tire Wastes in a Flaming Pyrolyzer Minimizes Discharges to the Environment Claro I. Sainz-Diaz,* ,† David R. Kelly, ‡ Chistopher S. Avenell, § and Anthony G. Griffiths § Estacion Experimental del Zaidin (C.S.I.C.), Prof. Albareda, 1. 18008-Granada, Spain, Department of Chemistry, University of Wales, Cardiff, CF1 3TB, Cardiff, U.K., and Mechanical Engineering and Energy Studies, School of Engineering, University of Wales, Cardiff, CF2 1YF, Cardiff, U.K. Received January 3, 1997 X Wood furniture waste and scrap tires were pyrolyzed in a pilot scale batch flaming pyrolyzer. The effect of temperature, fuel/air ratio, and reaction times on the temperature distribution, gas and char pyrolysis yields, oxygen levels, SO 2 and NO x emissions, and pyrolysis gas composition were studied. Low emission levels of NO x , SO 2 , and heavy metals were observed in the pyrolysis of wastes with high content of nitrogen (chipboard), sulfur, or heavy metals (scrap tires), respectively. The main components of the pyrolysis gas were acetylene, methane, and carbon monoxide. Gas chromatographic, GC-MS, and FT-IR studies of the heavy hydrocarbons fraction of pyrolysis gas were consistent with each other and showed the presence of alcohols, carboxylic derivatives, heterocyclic and phenolic compounds in furniture waste pyrolysate, and aromatic compounds in tires pyrolysate. Kovats indices for GC-MS retention times were calculated for a series of organic compounds of environmental interest. Organic compounds in the pyrolysate were identified from mass spectra and by comparison of retention times with authentic standards or published Kovats indices. The heating value of the pyrolysis gas from furniture waste and scrap tire was 8.7 and 5.6 MJ/m 3 , respectively. Introduction The environmental problems of the disposal of diverse industrial and domestic solid wastes has grown consid- erably in recent years. At the same time dwindling stocks of fossil fuels in some regions and particular environmental problems with the emissions from the combustion of these fuels have led to research into the potential of using solid waste either as a supplementary supply of energy or for conversion to an alternative fuel. 1 Currently, the most widely used method of waste exploitation is landfilling in many developing countries, 2 but this has important hazard risks, such as leakage of toxic chemicals, uncontrolled emissions of gases, ac- cidental fires, long breakdown times, etc. Direct incin- eration and biodigestion are strong alternatives. How- ever, such processes are somewhat restricted in the types of waste material that can be utilized along with operational restrictions inherent in the process that lead to limits on their performance. 3 Biomass is one of the main groups of solid wastes. It is mainly generated by the agricultural, farming, forestry, furniture, food, and paper-making industries. This biomass has no highly toxic constituents. However, if poorly processed, it can still be a significant pollutant especially in landfill and uncontrolled incineration processes. The consumption of biomass by open burning is known to produce products of partial combustion, some of which are known carcinogens. Biomass has an important role as a combustible product, being the main fuel in developing countries (Figure 1). 1,4,5 One difficult group of wastes is that from the furniture industry. Although the main waste is generated before the painting process, many raw components are wood composites, containing urea- formaldehyde, phenol-formaldehyde, and isocyanates resins. In 1990, wood composite production reached an estimated total of about 125 million m 3 worldwide. Over 40% of this volume involved plywood and OSB (oriented strandboard) products, which contain about 700 kt of phenol-formaldehyde resin solids as the primary ad- hesive binder. 6,7 Urea-formaldehyde resin is the only one used in the U.K. for the manufacture of chipboard. It is also used in most MDF (medium-density fiber- board) and is sometimes combined with melamine. 8 The incineration of these wood composites can cause severe pollution problems. 9 Another important environmental problem is heavy metal emissions from waste incinera- * To whom correspondence should be addressed. † Estacion Experimental del Zaidin (C.S.I.C.). ‡ Department of Chemistry, University of Wales. § School of Engineering, University of Wales. X Abstract published in Advance ACS Abstracts, August 15, 1997. (1) Syred, N. Waste Energy Utilization Technology; School of Engi- neering, University of Wales: Cardiff, U.K., 1993. (2) Nels, C. H. In Pyrolysis and Gasification; Ferrero, G. L., Maniatis, K., Buekens, A., Bridgwater, A. V., Eds.; Elsevier: London, 1989; pp 379-386. (3) Beenackers, A. A. C. M.; Bridgwater, A. V. In Pyrolysis and Gasification; Ferrero, G. L., Maniatis, K., Buekens, A. Bridgwater, A. V., Eds.; Elsevier: London, 1989; pp 129-155. (4) Arshad, A. S. Ph.D. Thesis, Department of Mechanical Engineer- ing, University of Wales, Cardiff, U.K., 1993. (5) Avenell, C. S. Ph.D. Thesis, Department of Mechanical Engi- neering, University of Wales, Cardiff, U.K, 1997. (6) Tiedeman, G. T.; Isaacson, R. L.; Sellers, T. For. Prod. J. 1994, 44 (3), 73-75. (7) Gardner, D. J.; Sellers, T. For. Prod. J. 1986, 36 (5), 61-67. (8) Dinwoodie, J. M.; Higgins, J. A.; Paxton, B. H.; Robson, D. J. Wood Sci. Technol. 1991, 25 , 383-96. (9) Littorin, M.; Truedsson, L.; Welinder, H.; Skarping, G.; Mar- tensson, V.; Sjoholm, A.-G. Scand. J. Work, Environ. Health 1994, 20, 216-22. 1061 Energy & Fuels 1997, 11, 1061-1072 S0887-0624(97)00003-0 CCC: $14.00 © 1997 American Chemical Society