María A. Garrido

Pollutant emissions during the pyrolysis and combustion of flexible polyurethane foam

Thermal decomposition of flexible polyurethane foam (FPUF) was studied under nitrogen and air atmospheres at 550°C and 850°C using a laboratory scale reactor to analyse the evolved products. Ammonia, hydrogen cyanide and nitrile compounds were obtained in high yields in pyrolysis at the lower temperature, whereas at 850°C polycyclic aromatic hydrocarbons (PAHs) and other semivolatile compounds, especially compounds containing nitrogen (benzonitrile, aniline, quinolone and indene) were the most abundant products. Different behaviour was observed in the evolution of polychlorodibenzo-p-dioxins and furans (PCDD/Fs) at 550°C and 850°C. At 550°C, the less chlorinated congeners, mainly PCDF, were more abundant. Contrarily, at 850°C the most chlorinated PCDD were dominant. In addition, the total yields of PCDD/Fs in the pyrolysis and combustion runs at 850°C were low and quite similar.

Pollutant formation in the pyrolysis and combustion of Automotive Shredder Residue.

The present work has been carried out to verify the feasibility of thermal valorization of an automobile shredder residue (ASR). With this aim, the thermal decomposition of this waste has been studied in a laboratory scale reactor, analyzing the pollutants emitted under different operating conditions. The emission factors of carbon oxides, light hydrocarbons, PAHs, PCPhs, PCBzs, PBPhs, PCDD/Fs, dioxin-like PCBs and PBDD/Fs were determined at two temperatures, 600 and 850°C, and under different oxygen ratios ranging from 0 (pure pyrolysis) to 1.5 (over-stoichiometric oxidation). After analyzing all these compounds, we conclude that thermal valorization of ASR is a clean way to treat this waste.

Pollutant emissions from the pyrolysis and combustion of viscoelastic memory foam

Thermal degradation of viscoelastic memory foam (VMF) in a horizontal laboratory scale reactor has been studied. Pyrolysis and combustion experiments under sub-stoichiometric conditions were performed at four different temperatures (550°C, 650°C, 750°C and 850°C) for the determination of pollutants. Analyses of gas and semivolatile compounds, including polychlorodibenzo-p-dioxins and furans (PCDD/Fs) and dioxin-like polychlorobiphenyls (dl-PCBs) are shown. From the results, it was deduced that pyrolytic conditions favor the formation of PAHs, methane, ethylene, NH3 and dl-PCBs, whereas the presence of oxygen involves a higher emission of PCDD/Fs and simple N-containing compounds such as NO and HCN. The toxic levels calculated for PAHs, PCDD/Fs and dl-PCBs in all cases were low confirming that the incineration of VMF mattress waste could be a good option for waste management. Nevertheless, relatively high emissions of NO, NH3 and HCN were obtained and their reduction must be considered.