Determination of the activation energies of beef tallow and crude glycerin combustion using thermogravimetry

Autor(es)

Crnkovic, Paula Manoel ^{[1, 2]} ; Koch, Christoph ^[3] ; Avila, Ivonete ^[1] ; Mortari, Daniela Andresa ^[1] ; Cordoba, Aymer Maturana ^[1] ; dos Santos, Antonio Moreira ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sao Carlos, SP - Brazil

^[2] Paulista State Univ Unesp, Inst Chem, Araraquara - Brazil

^[3] Leibniz Univ Hannover, Hannover - Germany

• Tipo de documento: Artigo Científico
• Fonte: BIOMASS & BIOENERGY; v. 44, p. 8-16, 2012.
• Citações Web of Science: 26

Resumo

The present study deals with the determination of the activation energy for the thermal decomposition of two renewable fuels crude glycerin and beef tallow. The activation energies were investigated by using a thermogravimetric analyzer (TGA) in the temperature range of 25-600 degrees C in atmosphere of synthetic air. The TG curves of the thermal decomposition process of both samples were divided into several phases and the second, called PH2, was chosen for the kinetic study because it is associated with the combustion ignition. Differential Thermal Analysis (DTA) showed an endothermic event at the PH2 region for the crude glycerin corresponding to devolatilization, while for beef tallow, this step presented an exothermic event, called LTO (low-temperature oxidation), which is correlated with devolatilization followed by combustion. For the entire PH2, activation energy values for crude glycerin were between 90 kJ mol(-1) and 42 kJ mol(-1), while for the beef tallow they ranged from 50 kJ mol(-1) to 113 kJ mol (1). The activation energy values obtained at the pre-ignition stage - conversion between 0 and 0.45 - showed that the crude glycerin with higher values requires an additional energetic support at the start of combustion processes and the beef tallow ignites more easily, presenting lower values. According to the Wolfer's equation, a direct relation between the activation energy and the ignition delay is established and the results of this study provides useful data for the development and design of new combustion chambers and engines when non-traditional fuels are used as feedstock. (C) 2012 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 11/00183-2 - Emprego de análise térmica e forno tubular de queda livre (DTF) para estudar a eficiência térmica de carvões minerais, bagaço de cana-de-açúcar e suas misturas
• Beneficiário: Daniela Andresa Mortari
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 11/11321-7 - Estudo do Comportamento do Decaimento da Capacidade de Sorção de CO2 por Calcários aplicado à Tecnologia de Sequestro de Carbono
• Beneficiário: Ivonete Ávila
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado