Thermal Plasma Assisted Gasification of Empty Fruit Bunch Biomass using Air-Suction Downdraft Strategy: Effect of Equivalence Ratio and Temperature Profile Characteristic

Abstract

Plasma gasification is a highly efficient technology in enhancing process rates and gas yield compared to conventional gasification due to its extremely high operational temperatures. However, the operational performance using palm oil biomass in Malaysia as feedstock is still unclear. Hence the present study aims to investigate the effect of equivalence ratio (ER) and temperature on the performance of palm empty fruit bunch biomass (EFB) gasification assisted with plasma reaction process in producing syngas. The performance of produced syngas in terms of the gas composition, yield, lower and higher heating value, cold gas, and carbon conversion efficiency were carefully investigated. The reactor type of air-suction downdraft arrangement has been used in this study. The reactor was then assisted with the DC-thermal arc plasma reaction in the oxidation zone with the maximum power of 9 kW that is applicable to provide a reaction environment temperature of above 1200^oC. The result showed that EFB gasification process assisted with plasma produced higher composition of H₂ at lower ER. In contrast, higher CO was produced at higher ER. The extreme high temperature of plasma extent the production of CO by breaking the bonding of CO₂ component either from the produced gas or gasifying agent of air. The characteristic of temperature distribution during the gasification process showed a highly fluctuation profile in the oxidation zones. This is due to the simultaneous exchange between produced gas in the pyrolysis zone and incoming supply of gasifying agent in the reactor inlet. This indicates that the reaction characteristic of plasma gasification is considerably identified with the conventional method. This study is important to identify the optimum operational condition of EFB plasma gasification in terms of the range of ER and temperature distribution characteristic.