Ampliando o conceito do fator de severidade para a hidrólise ácida de microalgas incluindo os tempos transientes de processo

Abstract

An important preoccupation in Brazil and Worldwide, is concerned to find solutiojns that reduce energy dependence on fossil fuels, searching to processes that cause less impact in the environment. To meet the growing demand for ethanol, without competing with arable lands for food production, lignocellulosic materials and algae can be used to use the polysaccharide fraction to obtain fermentable sugar for bioethanol production. This study investigated the acid pretreatment of microalgae biomass with the solubilized biomass analyzed through the severity factor approach - Acidic Combined Severity Factor (CSF). A suitable kinetic model was developed and applied, showing that the theory severity factor can be revised and expanded. Comparisons and discussions were made regarding models in the literature, which are mainly related to lignocellulosic biomass. Two regions of the microalgae acid treatment process were analyzed: regions of low and high reactivity. Reaction orders for biomass and acid were calculated from kinetics of order n. The kinetic concept of severity factor in the prediction of the effectiveness of acid hydrolysis was expanded using microalgae biomass considering the inclusion of the transient process times (heating/cooling), proposing a range of ln CSF that may have less dispersion even considering different temperatures (110- 130 oC), residence times (0-60 min) and acid concentrations (0-5% v/v).