Behavior and Syngas Characteristics with Alternative Inlet Air Configurations in Fluidized Bed Gasification of Oil Palm Biomass.

This study investigated the behavior and syngas characteristics of oil palm biomass fluidized bed gasification (FBG) with alternative inlet air configurations. The air was supplied to the combustion zone of the FBG with tangential and updraft air inlet (TI and UI) modes. A mixed oil palm decanter cake was used as feedstock at 3 kg/h feed rate. The experiments were done at the equivalence ratios (ERs) from 0.1 to 1.0. The experimental results showed that the air supply mode and ER affected the temperature distribution inside the gasifier. Operation with TI mode had combustion initiated at the side, then propagated through the middle section, while in UI mode, the combustion reaction was at the center of the chamber. With TI mode, the temperature at combustion zone was around 600 °C. At ER 0.5, this zone covered the heights from 0.25 to 0.75 m. In UI mode, the highest temperature was near 800 °C, but combustion was prominent only in a zone near the bottom. The CFD simulations showed that the alternative inlet air configurations and the ER influenced flow patterns. CFD confirmed the swirling streamlines in TI mode, while UI mode showed a localized elevated temperature, particularly at 0.25 m height. Syngas composition analysis indicated that operation in TI mode at ER of 0.7 provided the larger combustion zone, leading to better syngas product in terms of CO (> 20%) and H2 (> 8%) components. This mode also provided the best 5.1 MJ/m3 energy content for syngas. The results of this study can provide useful guidelines for further investigations of FBG with tangential air inlet. [ABSTRACT FROM AUTHOR]