Physical and chemical characteristics of products from the torrefaction of yellow poplar (Liriodendron tulipifera)

► We investigated the characteristics of torrefied yellow poplar. ► The carbon content of torrefied biomass was increased with increasing temperature. ► The calorific value increased by 18% comparing to that of original biomass. ► The grindability of torrefied biomass was significantly improved at high temperature. We investigated the characteristics of torrefied yellow poplar (Liriodendron tulipifera) depending on reaction time (30min) and temperature (240–280°C). The thermogravimetric, grindability and calorific value of torrefied biomass were analyzed. As the torrefaction temperature increased, the carbon content of torrefied biomass increased from 49.50% to 54.42%, while the hydrogen and oxygen contents decreased from 6.09% to 5.65% and 28.71% to 26.61%, respectively. The highest calorific value was 1233kJ/kg when torrefaction was performed at 280°C for 30min. An overall increase in energy density and decrease in mass and energy yield was observed with the increase in torrefaction temperature. The analysis of thermal decomposition demonstrated that the hemicelluloses contained in torrefied biomass decreased with increasing torrefaction temperature, whereas cellulose and lignin were only slightly affected. The grindability of torrefied biomass was significantly improved when torrefaction was performed at high temperature. Torrefaction of yellow poplar improved the chemical and physical fuel properties of the biomass.