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Waste electrical and electronic equipment (WEEE) has become a critical environmental problem. Catalytic pyrolysis is an ideal technique to treat and convert the plastic fraction of WEEE into chemicals and fuels. Unfortunately, research using real WEEE remains relatively limited. Furthermore, the complexity of WEEE complicates the analysis of its pyrolytic kinetics. This study applied the Fraser-Suzuki mathematical deconvolution method to obtain the pseudo reactions of the thermal degradation of two types of WEEE, using four different catalysts (Al2O3, HBeta, HZSM-5, and TiO2) or without a catalyst. The main contributor(s) to each pseudo reaction were identified by comparing them with the pyrolysis results of the pure plastics in WEEE. The nth order model was then applied to estimate the kinetic parameters of the obtained pseudo reactions. In the low-grade electronics pyrolysis, the pseudo-1 reaction using TiO2 as a catalyst achieved the lowest activation energy of 92.10 kJ/mol, while the pseudo-2 reaction using HZSM-5 resulted in the lowest activation energy of 101.35 kJ/mol among the four catalytic cases. For medium-grade electronics, pseudo-3 and pseudo-4 were the main reactions for thermal degradation, with HZSM-5 and TiO2 yielding the lowest pyrolytic activation energies of 75.24 and 226.39 kJ/mol, respectively. This effort will play a crucial role in comprehending the pyrolysis kinetic mechanism of WEEE and propelling this technology toward a brighter future., QC 20240815 more...

Ex situ catalytic pyrolysis of engineered waste electrical and electronic equipment (WEEE) was conducted in a two-stage reactor using HZSM-5 catalyst. The effect of the catalysis temperature and the catalyst-to-feedstock (C/F) ratio on products yield, gas and oil composition, and products characterization were investigated in this study. Results indicated that lower reforming temperature and C/F ratio favored organic fractions production. The highest yield of organic fraction was obtained at a catalysis temperature of 450 °C and at a C/F ratio of 0.15, corresponding to 28.5 and 27.4 wt %, respectively. The highest selectivity toward aromatic hydrocarbons and the lowest TAN value of the organic fraction were obtained at a catalysis temperature of 450 °C and a C/F ratio of 0.2, respectively. Most of the alkali and transition metals and 23 % of Br remained in the solid residue after the catalytic pyrolysis of low-grade electronic waste (LGEW)., QC 20240506 more...

Non-catalytic and catalytic pyrolysis of two waste electrical and electronic equipment (WEEE) fractions, with two different copper contents (low-and medium-grade WEEE named as LGE and MGE, respectively), were performed using micro-and lab-scale pyrolyzers. This research aimed to fundamentally study the feasibility of chemical recycling of the WEEE fractions via pyrolysis process considering molecular interactions at the interfaces of catalyst active sites and WEEE pyrolyzates which significantly influence the chemical functionality of surface intermediates and catalysis by reorganizing the pyrolyzates near catalytic active sites forming reactive surface intermediates. Hence, Al2O3, TiO2, HBeta, HZSM-5 and spent FCC catalysts were used in in-situ micro-scale pyrolysis. Results indicated that HBeta and HZSM-5 zeolites were more suitable than other catalysts for selective production of aromatic hydrocarbons and BTX. High acidity and shape selectivity of zeotype surfaces make them attractive frameworks for catalytic pyrolysis processes aiming for light hydrocarbons like BTX. Meanwhile, the ex-situ pyrolysis of LGE and MGE were carried out using HZSM-5 in micro-and lab-scale pyrolyzers to investigate the effect of pyrolysis configuration on the BTX selectivity. Although the ex-situ pyrolysis resulted in higher formation of BTX from LGE, the in-situ configuration was more efficient to produce BTX from MGE., QC 20221010 more...