On the accuracy of CO/H2 kinetic mechanisms:for prediction of syngas non-premixed flames characteristics

Abstract

Gasification is a widely used thermo-chemical route for conversion of biomass and coal, yields fuel gases rich in carbon monoxide and hydrogen (called syngas or producer gas). Due to the toxic nature of CO, an accurate kinetic mechanism is required for the prediction and control of its emission from gasification based combustion devices (domestic and commercial scale biomass-based cooking devices, stationary gas turbines, industrial furnaces etc.). CFD simulation results from earlier studies clearly depict the incapability of available kinetic mechanisms for the prediction of the Sandia-ETH Zurich turbulent syngas jet diffusion flames characteristics. The two main reasons for this inaccuracy are, (1) modelling of turbulence-chemistry interactions, (2) optimization of kinetic mechanism rate parameters. To check the accuracy of kinetic rate parameters of available CO/H2 kinetic mechanisms (5 detailed and 3 short kinetic mechanisms) for syngas non-premixed flames, a simplified canonical configuration namely; laminar jet diffusion is studied both experimentally and computationally. The flame height comparison of 6 different compositions of CO/H2 laminar jet diffusion flames showed that none of the mechanisms is capable of accurately predicting experimental flame height and thus highlight a need for a new optimized kinetic mechanism for Syngas combustion