: In this research entrained flow gasifier is modeled through commercially available Computational Fluid Dynamics (CFD) software Ansys Fluent^®14. The general continuity equation, energy equation, and Navier-Stoke fluid flow equations were solved using the CFD modeling approach. The mathematical modeling was done using differential partial equations. The turbulence was predicted using the standard k-ε turbulence model. Co-gasification of coal and biomass for syngas production is considered environmentally friendly. Numerous thermal conversion technologies have been used for the co-gasification of coal and biomass, but multiple opposite burner (MOB) gasifiers got more attention because of their higher efficiency during the gasification of low-grade coal and biomass. The MOB gasifiers are commonly used for coal and biomass gasification. However, MOB gasifiers were not used with the combination of low-grade coal and biomass. The efficiency of the gasifier was predicted by changing the mixing ratio of coal with biomass, feed flow rate, and oxygen-to-carbon ratio. Three biomasses were used including rice husk, sugarcane bagasse, cotton stalks, and lignite coal mixture. According to the results, mixing coal with biomass significantly impacted the syngas composition, char conversion, and operational temperature. The mole fraction of CO was achieved at 0.344, and the H₂ mole fraction was obtained at 0.155 with 10% coal and 90% rice husk at 0.1 kg/sec feed flow rate and 1.0 O/C ratio. Char conversion and syngas composition were significantly affected by varying O/C ratios. With an increasing O/C ratio from 0.8 to 1.2, the mole fraction of H₂ and CO in syngas composition increases and decreases. The optimum O/C ratio was found at 1.0. At this O/C ratio, the syngas exit temperature was observed at a minimum, and char conversion was observed at a maximum.

Keywords: Mathematical Modelling, Partial Differential Equations, Navier Stoke’s Equation, Energy Equation, Computational Fluid Dynamics