Torrefied mustard straw as a potential solid biofuel: A study with physicochemical characterization, thermogrevimetric and emission analysis

Abstract

Abstract Torrefaction enhances the properties of biomass fuels which adds to their suitability as energy sources. Due to abundance availbiluty of mustard straw in the northern region of India and throughout the globe, the raw or torrefied mustard straw were investigated in the present study. The torrefaction experiments were conducted on mustard straw using heating temperatures of 200°C, 250°C, and 300°C for 60 minutes. The biomass characterization were carried out using proximate analysis, ultimate analysis, and High Heating Values (HHV). Afterward, NOx, SO2, CO2, CO, and dust emissions are evaluated from the combustion of raw/torrefied mustard straw. After the experimentation, the results have been compared with the literature. It was observed that during torrefaction, the carbon content of biomass increases with the increase in temperature, while the hydrogen and oxygen contents decreased. Further, the liginin content increases while hemicellulose content decomposes with the increase in temperature. It was seen that energy yield for a torrefied mustard straw at 200°C, 250°C, and 300°C was 76.24%, 88.98%, and 94.75%, respectively. The process of torrefaction, increases the bulk density, decreased the mass yields and improves the ignitability indices of the mustard straw. The outcomes of this research are expected to provide practical insight into how raw mustard straw can be upgraded into densified solid biofuels suitable for industrial and thermal power plant applications.