Segregação de misturas binárias de areia e compósito PEBD/Al em leito fluidizado para pirólise rápida de resíduos cartonados
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Data
2020-03-23
Autores
Santos, Antonio Carlos Oliveira
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Universidade Federal do Espírito Santo
Resumo
With the accelerated population growth experienced today, solid waste generation is increasing. Aiming at a better energy use, thermo-chemical routes for waste treatment are being sought. In the carton packaging waste sector, pyrolysis is the only route that allows the recovery of aluminum on an industrial scale - due to the devolatization of polyethylene. The fluidized bed reactor is an alternative for rapid pyrolysis of the polyethylene and aluminum composite (LDPE/Al). However, the use of a bed composed of binary mixture of sand and composite polyethylene and aluminum, can generate segregation of particles. Particulate segregation can cause defluidization of the bed and reduce the heat transfer rate and compromise the recovery of aluminum via LDPE/Al pyrolysis. To evaluate the segregation of binary mixtures of sand and LDPE/Al, experiments were conducted in a cylindrical column of 10 cm in diameter and 17 cm in height. The bed was composed of mixtures of sand particles with a diameter of 0.45 mm and LDPE/AL with a range of 0.3 to 2.85 mm. Thus, the objective of this study was to perform a planning of factor 33 experiments, with three central points, to evaluate the effect of the mixing mass fraction factors (XC% w/w), air velocity (V/Vmf) and sand particle diameter ratio and LDPE/AL (dC/dS) on the mixing index (IM). The composite ratios in the mixture were 10 to 30% w/w. Under the investigated conditions, air velocity in a range of 10 to 40% above the minimum fluidization was employed. The use of the planning of experiments made it possible to adjust a statistical model to predict the mixing index. The statistical analysis of the data revealed that only the factors dC/dS and V/Vmf had an effect on IM. The optimal operational conditions (with IM 1) were achieved with values of 0.667 of composite and sand diameter ratio, 10% of air velocity and 15% w/w of composite mass fraction. The statistical model obtained was adequate to predict the values of the mixture index with an error lower than 15%. With the low levels of segregation achieved by the bed in the optimal operational conditions, this contact system can be indicated for the pyrolysis of LDPE/Al, thus allowing the recovery of aluminum.
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Reciclagem do alumínio , misturas binárias , reator de partículas , modelagem estocástica , eficiência energética