Marcelo Silveira Bacelos

Determination of activation energy of pyrolysis of carton packaging wastes and its pure components using thermogravimetry

Many processes have been used for recycling of carton packaging wastes. The pyrolysis highlights as a promising technology to be used for recovering the aluminum from polyethylene and generating products with high heating value. In this paper, a study on pyrolysis reactions of carton packaging wastes and its pure components was performed in order to estimate the kinetic parameters of these reactions. For this, dynamic thermogravimetric analyses were carried out and two different kinds of kinetic models were used: the isoconversional and Independent Parallel Reactions. Isoconversional models allowed to calculate the overall activation energy of the pyrolysis reaction, in according to their conversions. The IPR model, in turn, allowed the calculation of kinetic parameters of each one of the carton packaging and paperboard subcomponents. The carton packaging pyrolysis follows three separated stages of devolatilization. The first step is moisture loss. The second stage is perfectly correlated to devolatilization of cardboard. The third step is correlated to devolatilization of polyethylene.

Dynamic analysis of reaction kinetics of carton packaging pyrolysis

Abstract As reported in the literature, the post-consumption carton packaging has been recycled using different process. Pyrolysis can be a promising technology to be used for recovering the aluminum from polyethylene and generating products with high heating value. In this research paper, by using thermogravimetric analysis (TGA), a kinetic study on pyrolysis reactions was performed. Furthermore, the activation energy of pyrolysis reaction was estimated using the methodology proposed by Ozawa (1965).

Factor effect of operating conditions on the leaching of fly ashes from a pulp and paper mill

The non-process-elements (NPEs) in the pulp and paper production, in particular chloride (Cl-) and potassium (K+), eventually accumulate in a sodium sulfate recovery cycle of a paper plant, especially on boiler fly ashes (flue gas cleaning). This accumulation often leads to fouling and corrosion. Thus, in order to reduce such problems, a leaching unit is typically integrated aiming to remove Cl- and K+ and recover sodium sulfate (Na2SO4) from boiler fly ashes. In this context, this research is focused on investigating the effects of temperature, ash concentration and pH on the separation efficiency (Cl- and K+ removal and Na2SO4 recovery) of recovery boiler fly ashes using design of experiments in a devised laboratory setup. As expected from the literature, the results obtained reveals that concentration has the most significant effect on the response variables followed by temperature; whereas pH, not mentioned in this application so far, also has a significant effect. The optimum operating condition, which yields 84 wt% of Na2SO4 recovery and 97 wt% of Cl- and K+ removal, is achieved at 60 °C, 50 wt% of ash and pH 9.0. For practical applications, this optimal condition reduces the accumulation of NPEs and mitigates the risks of fouling and corrosion.

ANÁLISE DO PROCESSO DE LIXIVIAÇÃO DAS CINZAS DE CALDEIRAS DE RECUPERAÇÃO QUÍMICA

RESUMO – Na industria, o acumulo de substâncias (cloreto e o potassio) nao processaveis no ciclo de recuperacao de produtos quimicos na caldeira pode causar corrosao e incrustacao nos equipamentos. A lixiviacao das cinzas da caldeira de recuperacao quimica e uma tecnica viavel que promove a remocao seletiva destes componentes. Dessa maneira, o objetivo deste trabalho e analisar o processo de lixiviacao de cinzas, verificando o efeito das variaveis de processo (temperatura, massa especifica da lama e pH) sobre o grau de separacao das fases, mediante ensaios de decantacao. A analise dos dados indicou que as variaveis de processo que afetam significativamente a separacao das fases sao a massa especifica e o pH. Os valores otimos que maximizam a variavel resposta foram de 1,35 g/mL para passa especifica e 8,5 para o pH.

Quantification of Phase Compositions Present in the System [(NiO)x].[(CoO)1-x].[(Al2O3)], 0.05 ≤ X ≤ 0.95, and the Effect in the Electrical Properties of Semiconductor as a Consequence of the CO+2 Variation

In this work were investigated the systems-NiOx-CoO1-x-Al2O3 using X-ray diffraction of the powder, which identified and quantified to phase in the sample was performed through the Rietveld method. The insertion of nickel oxide in the system obeyed the proportions of molar fraction of 0,05, 0,30, 0,50, 0,70 and 0,95 (x). Analyses were realized on samples which were treated at the temperature 1773K. From the results of refinement of spinel phase structure, was analyzed the relationship between lattice parameter refinement and the substitution of Co+2 ion by Ni+2ion in the structure. The electrical resistivity dc was observed as a respect to temperature and the results appears a decrease of resistivity when were simultaneously increased the temperature. It was observed that the conduction mechanism was the same in all samples and the results for activation energy, characterized like electron hopping, it due exchange setting the ion Co+2 D Co+3.