Comparison of the gasification performance in the downdraft fixed-bed gasifier fed by different feedstocks: Rice husk, sawdust, and their mixture

Abstract

In order to figure out the compatibility of downdraft gasifiers on different feedstocks, performance of a fixed-bed downdraft gasifier fed by rice husk, sawdust, and their mixture (1:1 by mass) are compared in the present work. Gasification is performed with varying equivalence ratio, i.e. 0.15, 0.20, and 0.25. Gasification air is injected into the reactor via three tuyers located at 330 mm above the grate. Gasification characteristics (temperature profile of the reactor, fuel consumption rate, volume fraction of CO, H2, and CH4 in the producer gas) and performance of the gasifier (lower heating value of the producer gas and cold gas efficiency of the gasifier) are observed and analyzed. The results indicate that the gasifier is compatible for rice husk, sawdust, or their mixture. Optimum equivalence ratio for gasification of the rice husk, sawdust, and the mixture are 0.20, 0.20, and 0.15, respectively. At the optimum equivalence ratios, lower heating values of the producer gas are 3.13, 2.69, and 0.35 MJ/Nm3 for rice husk, sawdust, and the mixture. Meanwhile, cold gas efficiencies are 72.73%, 69.27%, and 82.08%, correspondingly.