Transcripción del resumen del autor. The generation of scrap tires in the world is approximately 1 billion per year and is set to increase in the foreseeable future as the number of cars on the roads increases. In this paper we present results from a pilot scale study on the cofiring of fine tire rubber (FTR) powder and plastic (high-density polyethylene, HDPE) with pulverized coal (PC) with a view to an application in power generation as an alternative to biomass, particularly their role in the combustion behavior of PC. We have performed experiments with a South African (SAf) coal and a South American (SAm) coal of different composition for a range of cofiring levels, up to 25%, and several configurations of combustion air distribution (air-staging). The fuels were fired through the burner and particular regard was paid to the effect on CO2, NOx, SO2, and carbon burnout. The results show that coal quality has a significant role during cofiring. In present investigations when HDPE was cofired with the SAm coal, a significant reduction in NOx was observed. Lower NOx emissions are achieved due to the different combustion behavior of the fuels. That is, modifying the primary combustion zone environment makes it more difficult for the intermediate HCN and NH3 species to oxidize to NOx due to the reduced O2 concentration at the point of fuel-N release in the flame. The influence of the tire-N content is thought to be small in the flames studied. We have seen around 20% NOx reductions when cofiring tire with the SAf coal for a 20% tire/coal cofiring ratio but insignificant NOx reductions when cofiring tire with SAm coal under the same conditions, indicating similar combustion characteristics and flame dynamics. In all cases, good burnout was achieved with less than 8% carbon in ash. The reduction of NO by the cofiring of tire-coal and plastic-coal fuel blends was further compared to historical literature involving the cofiring of biomass. It is noted that the ignition behavior of fuels of tire and plastic may differ to that of biomass; however, the overall reduction in NO is still observed in both cases. Historical air-staged experiments involving the cofiring of biomass were not able to provide similarly high reductions of NO to the staged cofiring of tire-coal and plastic-coal fuel blends. It is thought that the particle size of the biomass fired is a significant factor that is influencing the NO reduction efficiencies within a staged flame.

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