Modelagem e Simulação de Reatores Tubulares Recheados sob Condições Supercríticas: Influência das Características de Partículas Inertes na Conversão de Triglicerídeos

Abstract

Biodiesel is a renewable fuel obtained by the conventional route of catalytic transesterification, once this route presents an easily applied methodology, high reaction yields and the similarity between its obtained product and the standard diesel. Besides, the supercritical transesterification in tubular reactors constituted by inert bed, approach recently researched to the biodiesel production, comes up as a possible substitute to the standard route because it is a catalyst-free process and reduces the quantity of stages in the production process. The factors considered in this process are the employment of temperatures and pressures aobve the supercritical conditions, the high oil:alcohol ratio and the material used to fill the bed. The temperature, pressure and the ratio were widely studied, but the literature still presenting a lack of studies about the inert filling, mainly about the role of the thermal properties of inert material applied in the process. Thus, this study aims to develop a phenomenological model based on the mass and energy balance to the supercritical transesterification in order to examine the influence of the material which constitutes the bed filling in the triglycerides conversion. The process variables chosen to evaluate the process were the temperature (at 573K, 623K and 673K), the volumetric flow (0.5mL/min and 1mL/min), as well as the thermal properties of two kind of bed filling: glass and stainless steel 316. The experimental data of triglycerides conversion were taken from literature, considering an oil:alcohol ratio of 1:40 and pressure at 15MPa, both as fixed conditions. The algebraic-differential system of equations developed in this work was solved numerically by applying the False-Transient method together with the Method of Lines through the EMSO software. The obtained results shows that the usage of materials with distinct thermal properties impacts only in the temperature distribution of the bed, being irrelevant to the final reaction yield.