Fast pyrolysis of sugarcane straw and its integration into the conventional ethanol production process through Pinch Analysis

Abstract

One way to improve the energy and environmental efficiency of an ethanol production process is through product diversification, as well as the use of agricultural residues via thermochemical routes such as fast pyrolysis. Thus, this study assesses the integration of fast pyrolysis of sugarcane straw into the conventional ethanol production process. The fast pyrolysis process was modelled and simulated in the Aspen Plus® software, using the Lumped Reaction kinetic model. The heat integration procedure was performed using the Pinch analysis, utilising the simulation results and assuming different percentages of straw recovery from the field (25%, 50%, and 75%). The straw pyrolysis model was validated with experimental data from other authors of the literature. The assumed configuration presented itself as self-sufficient in energy terms. Among several evaluated cases, those where heat integration was applied showed a significant increase in surplus electricity (Case IV 30.6%, Case VI 34.8%, and Case VIII 46.4%) in comparison to the Base Case (Case I). Thus, heat integration promotes a rise in energy efficiency, as well as product diversification in ethanol production plants.