Agglomeration of alumina sand in a fluidized bed straw gasifier at elevated temperatures

Abstract

The aim of this study was to investigate the agglomeration characteristics of alumina sand in a fluidized bed straw gasification system at various equivalence ratios (0·18, 0·21, 0·26, 0·34). The effect of ash content (0·0, 3·3, 27·8 and 43·5%) on the agglomeration of alumina sand was, also, investigated at various temperatures (620, 740 and 850°C) using a high temperature furnace. The results showed that agglomeration was affected by the ash content and temperature; the higher the ash content and/or the temperature the stronger was the bonding. It was, however, possible to operate the gasifier, without any agglomeration or slag problems, up to a temperature of 920°C. Although, this is higher than the temperature (800°C) at which silica sand was found to agglomerate, it is much lower than the fusion temperatures of the alumina sand (2000°C) and the straw ash (1054°C). It did, however, correspond to the initial deformation of wheat straw ash.