Synchronized torrefaction and pelleting (STP) was developed as a laboratory scale process to produce torrefied pellets with a single biomass material loading. Two fuel upgrading actions (torrefaction and pelleting) happened simultaneously with the assistance of ultrasonic vibration. It was found that STP elevated biomass temperature to above 200 degrees C in less than one minute and initiated torrefaction while biomass was pelletized in a mold. A feasibility study showed that STP consistently produced torrefied pellets with improved physical, thermochemical, and hygroscopic properties as an upgraded fuel for biomass co-combustion. STP was effective at enhancing the density and durability of torrefied pellets. Elemental analysis of torrefied biomass material showed increased carbon content, indicating higher heating values of torrefied pellets over non-torrefied biomass. Thermogravimetric analysis and Fourier transform infrared analysis revealed loss of hydrogen and oxygen-rich matters during STP. Finally, greater hydrophobicity of torrefied pellets was exhibited by less water and vapor absorption compared with non-torrefied biomass. (C) 2019 Elsevier Ltd. All rights reserved.