Prediction of performance of a downdraft gasifier using equilibrium modeling for different biomass materials

Modeling and Parametric Study for Maximizing Heating Value of Gasification Syngas

“…Generally, the CH4 concentrations predicted by the equilibrium model were very minimal (only trace amounts), while values obtained from the actual experiments were typically in the range of 0.8% to 2.8%. Similar results were reported in studies for the prediction of CH4 composition in syngas utilizing the equilibrium model of gasification (Zainal et al 2001;Gautam 2010). Gautam (2010) reported that the equilibrium model predicted only trace amounts of CH4 for temperatures above 800 °C.…”

“…The inverse relation also showed that the product gases CO and CO2 were competing for the same reactant component, namely the carbon. Similar trends have been reported in the work of different authors (Zainal et al 2001;Mathieu and Dubuisson 2002;Zainal et al 2002). The composition of the inert component N2 was predicted to be relatively high at lower reactor temperatures, where the steady production of other gas components would be just starting, and showed a decreasing trend up to a temperature of 600 °C.…”

“…A mean error of 0.13 was obtained between the predicted and experimental values of LHV for the variation in the oxidation zone temperature between 700 and 1200 °C. This showed that the equilibrium model of prediction was in good agreement with the experimental data at a satisfactory level of accuracy as compared to mean error values in other studies (Zainal et al 2001). …”

“…Table 9 also shows that the H2 concentration predicted by the model was found to be slightly higher than the experimental data for the equivalence ratio between 0.35 and 0.41. Such higher predictions of the H2 composition in syngas from the equilibrium model of gasification have been reported in other studies as well (Zainal et al 2001;Gautam 2010). The reason for such higher prediction by the model could be due to the assumption that all the tar produced during gasification will be broken down to the simple hydrocarbon forms (namely H2 and CH4).…”

“…2. Similarly, the equilibrium model of downdraft gasification developed by Zainal et al (2001) predicted only trace amounts of CH4 (0.64%) as compared to the experimental values in the range of 1.58% that were reported in the current study. Table 7 is a comparison of the predicted and experimental results for the gas components CO, CO2, H2, and N2 in syngas.…”