Semi-empirical model for estimating molar fraction of syngas produced by thermal cracking of wood tar

Abstract

To optimize the efficiency of the wood gasification, tar which limits the use of syngas in thermal engines must be reduced. The quantity, quality and composition of syngas produced after thermal cracking of tar were analysed, and mathematical equations formulated based on Newton’s bivariate polynomial interpolation were used to estimate the molar fraction of the gases. The conceptual analysis of the problem was based on experimental data of temperature and residence time, and the semi-empirical model was simulated using Matlab to predict the composition of the syngas and the tar content in the gas mixture. The thermal cracking of tar increased the amount of syngas produced; in particular, the molar fraction of carbon monoxide and hydrogen. The gasification energy efficiency also improved with temperature and residence time, as the quantity of tar was reduced during cracking. The model was validated by comparing the experimental and numerical data. Keywords: Syngas, Gasification, Pyrolysis, Residence time, Thermal cracking of tar, Semi-empirical model