Torrefaction pretreatment is applied to improve the fuel quality of biomass. However, by using torrefied char as a solid fuel, the energy market can introduce a sustainable feedstock. To increase the fuel characteristics of biomass, flue gas torrefaction is a promising procedure. In this study, we explored how torrefaction improves the energy content of a rice husk and pine wood, The torrefaction process was performed to characterize rice husks and pine wood in terms of energy yield, lignocellulose composition, surface morphology, thermal cracking performance, contact angle, particle size distribution, and scanning electron microscope in an oxidative and non -oxidative environment. Rice husk and pine wood were torrefied by using a stimulated flue gas environment under different severities (15-30 minutes) and the effects of temperature ( 250°C -300 °C ) and concentration (5 % O2 -15-% CO2 and 80-% N2 by vol%) on their products will be studied. This enhances the practicability of using torrefied biomass as a fuel and allows it to be applied as a promising alternative clean energy source. The study opens up new possibilities for biomass's clean treatment and energy utilization through an in-depth understanding of FGT mechanisms. Furthermore, this study’s result will indicate that FGT is a low-cost and safe pretreatment method at an industrial scale.