Simulación del proceso de producción de etanol anhidro desde mucílago de cacao CCN-51 Zona 6: Ecuador

Abstract

Bioethanol has become the most produced liquid biofuel worldwide and in Ecuador it’s allowed to be mixed with gas sharing up to 10% of the composition. Here, bioresources are abundant like crop residues from cocoa, whose production has raised intensely in recent years due to its high demand on international market. The objective of this work is to simulate the production process of dehydrated ethanol from CCN-51 cocoa mucilage, a non-profitable waste from cacao plantations. Aspen Plus® was used to simulate fermentations, ethanol recovery, distillation, rectification and dehydration. A 1000 liters mucilage treatment capacity per week for the plant was calculated. Previous studies determined parameters like sugar concentrations, fermentation kinetics and dehydration technology analysis, which are required to conduct the simulation. The NRTL thermodynamic method and technological scheme for production of ethanol from sugar cane were applied. As for the fermentation process, two models were set, one for sucrose inversion, and another for glucose and fructose conversion to ethanol with a conversion factor of 99% during 47 hours. An absorption column was designed in order to recover 98% of ethanol in ventilation stream coming from the reactor. Using the DSTWU model, values for reflux, stages number and feed stage were calculated to simulate a 9 stages distillation column which concentrates ethanol solution from 16% to 70% v/v, and a 27 stages rectification column which does it to 92% v/v. Then, an extractive column was modeled using the 3:1 relation for glycerol and ethanol, which is dehydrated to 97,54% v/v. Aspen Adsorption® was used to define a bed with molecular sieves to dehydrate ethanol to 99,6% v/v. Finally, an economic analysis with Aspen was carried out to estimate capital costs.