Enhancing fuel characteristics of jute sticks (Corchorus Sp.) using fixed bed torrefaction process

Abstract

This is first article highlighting thermal degradation mapping of jute sticks in torrefaction regime. A critical investigation was done to torrefy the JS at four different temperatures (200 °C, 250 °C, 300 °C and 350 °C) and three different residence times (20 min, 40 min and 60 min) in fixed bed reactor. The effect of torrefaction on mass yield, energy yield, heating value, enhancement factor, degree of torrefaction, proximate analysis, ultimate analysis, grindability, and hydroscopicity was determined. Fourier transform infrared spectroscopy (FTIR) spectroscopy and Scanning electron microscopy (SEM) analyses were done to gain insights about chemical composition and morphological variations due to torrefaction process. The mass and energy yield of torrified jute sticks (TJS) were in the range of 68.45–85.31% and 85.87–99.99%, respectively. Results showed that, an increase in the carbon content was from 46.56 to 53.12% and HHV it was from 18.87 to 20.62 MJ/kg, respectively. The ratios of O/C and H/C decreased by 28.57% and 41.50%, respectively for highest torrefaction condition indicating that removal of hydrogen faster than oxygen. The energy-mass co-benefit index (EMCI) reaching the maximum of 17.63% at temperature of 350 °C and 20 min residence time. After torrefaction, grindability and hydrophobicity significantly improved. FTIR node at 1032.52, 1189.12, 1295.18 cm−1 showed stretch in cellulose, hemicellulose and lignin due to torrefaction. At higher temperature SEM structure of JS shows intergaps in structure due to release of volatile gases. Overall, torrefaction as a pre-treatment process showed the improvement in the characteristics of the JS.