Computational Fluid Dynamics Simulation of Downdraft Gasifier

Abstract

Gasification is the process of producing clean synthetic gas from Carbon based raw material. The producer gas (syngas) can be used as fossile fuel for electricity generation and chemical building block for petrochemical industries. The objective of this study is to design and investigate the numerical model of a fixed bed 10 kW down draft gasifier located at Nirma University by using ANSYS FLUENT 14.5. The design of the model has been created in Solidworks using actual experimental setup data. The ANSYS mesh modeler used for meshing. The Reynolds Average Navier-Stokes equations and nine species transport equations are solved with heterogeneous(solid-gas) and homogeneous(gas-gas) equations. Standard k-" model is used as turbulence model and P-1radiation model is used as radiation model. The steady simulations have been done. The equivalence ratio has been kept 0.20 for gasification process. The effect of different feed stokes and particle size on producer gases and temperature are analyzed. The species concentration, maximum temperature achieved and outlet temperature at exit gasifier are obtained and compared. The optimal value of particle size is 0.2-5mm. In case of feed stoke, the best suited feed stoke is titled as case 4 for the selected operating conditions.