Improving Lignocellulosic and Non-Lignocellulosic Biomass Characteristics through Torrefaction Process

In this study, three locally available biomasses, namely miscanthus, hops, sewage sludge, and additionally, their mixtures, were subjected to the torrefaction process to improve their fuel properties. The torrefaction process was conducted at 250-350 degrees C and 10-60 min in a nitrogen (N-2) environment. The torrefaction temperature and time were studied to evaluate the selected biomass materials; furthermore, heating values, mass and energy yields, enhancement factors, torrefaction severity indexes (TSI), and energy-mass co-benefit indexes (EMCI) were calculated. In addition, thermogravimetric (TGA) and Fourier transform infrared analyses (FTIR) were performed to characterize raw and torrefied biomass under the most stringent conditions (350 degrees C and 60 min). The results showed that with increasing torrefaction temperature and duration, mass and energy yields decreased, and heating values (HHVs) increased for all studied biomasses. The results of the TSI and EMCI indexes showed that the optimum torrefaction conditions were as follows: 260 degrees C and 10 min for pure miscanthus and hops, whilst this could not be confirmed for the sewage sludge. Furthermore, the combination of sewage sludge and the above-mentioned types of lignocellulosic biomass exhibited better fuel properties than sewage sludge alone.

Automated summary

This study focused on improving the fuel properties of locally available biomasses through the torrefaction process. The results showed that increasing torrefaction temperature and duration led to decreased mass and energy yields, and increased heating values. The optimum torrefaction conditions were determined for pure miscanthus and hops, but could not be confirmed for sewage sludge. Furthermore, the combination of sewage sludge and lignocellulosic biomass exhibited better fuel properties than sewage sludge alone.