Loblolly pine chips (about 15 mm × 6 mm) containing bark were obtained from a local wood product industry and were torrefied using a pilot-scale torrefaction unit (about 1 ton/day capacity), which was installed in North Carolina State University (Lake Wheeler Road Field Laboratory, Raleigh, NC). Three torrefied samples with different treatment temperatures (270, 300, and 330 °C) and residence time of 2.5 min were prepared and named as lightly (TA), moderately (TB), and severely (TC) torrefied biomass. Untorrefied biomass is indicated as “Raw” biomass for short. The weight loss of biomass during torrefaction was estimated using a linear correlation (R2 = 0.997) between the weight loss and the atomic O/C ratio, developed from lab-scale experiments with a tube furnace. The correlation was measured within the temperature range of 200–500 °C with seven data points. All samples were milled to 40–60 mesh using a Willey mill, and stored in an air-tightened plastic bag at 4 °C before further analyses.