Thermal pretreatment of sugarcane straw: physicochemical properties, combustion behaviour and emission prediction (#1409)

Authors

Assureira Espinoza, Estela

Assureira Espinoza, Marco

Abstract

Sugarcane straw is an agro-waste that can be used as fuel in thermochemical processes but it requires the modifications of their properties to mitigate some the negative issues that limits its use as fuel such as high moisture content, low density, fibrous structure, considerable amounts of alkalis and chlorine that cause slagging, fouling, and greenhouse emissions. This research presents the effects of a combined process developed for improving sugarcane straw properties, which integrates cutting, washing, and torrefaction pretreatments. The residue was chopped (20 mm), then a water washing pretreatment was applied testing three temperatures (20 °C and 80 °C), two residence time (10 min, 20 min) and two stirring conditions for a concentration of 3.33 %, being selected the washing condition that showed the highest removal of ash, alkalis, Cl and S. being found the condition carried out at 80 °C, 20 min and continuous stirring. Finally, the washed residue was torrefied at 250 °C for 20 minutes in a controlled oxidizing atmosphere within a reactor. The effectiveness of the treatment applied was determined by ultimate and elemental analysis, heating value, and ash analysis, according to ASTM standards. The combustion behaviour, the tendency for ash deposition, and corrosion and potential emissions was carried out by calculating prediction indices. The results obtained show the improvements achieved in the properties of sugarcane straw, enhancing the possibilities of its use as fuel in thermochemical processes, which is why the application of the treatment developed in this research is recommended.