Biomass is seen as a viable alternative energy source for replacing fossil fuel. However, the inherent properties of raw biomass, including high moisture content, low energy density, hydrophilic behavior, and fibrous nature, limit its use. Thus, pretreatment becomes an important step in the path of biomass to energy conversion routes. Torrefaction is One such emerging pretreatment process, which makes biomass hydrophobic, more energy dense, and easier to grind. This paper investigates the torrefaction process in a continuous two-stage, indirectly heated.rotary torrefier under the volatile gases medium. The rotary reactor is operated at different angular speeds, inclinations, and temperatures, and the produced torrefied solid product is characterized for physical and chemical compositions. The observed characteristics of the torrefied biomass produced under the volatile gases medium indicate that nitrogen supply can be avoided. Experimental= results showed that torrefaction temperature has a more significant effect than angular speed and inclination. At 320 degrees C, 4 rpm, and 1 degrees, fixed carbon in torrefied poplar is double that in raw poplar, with a solid mass yield of 80.2% and an increase in volumetric energy density of 8.9%. The energy balance showed the net system efficiency to be above 88%.