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Gasification is an attractive method to convert lignocellulosic biomass into a combustible gas mixture for electricity and power generation. To control the tar concentration in the produced gas to be within the allowable limit of downstream applications, it is important for a gasification system to be integrated with a tar removal process. In this study, an integrated gasification system consisting of a downdraft gasifier and a secondary catalytic tar‐cracking reactor was designed and tested for the gasification of pelletized oil palm empty fruit bunch. To further purify the producer gas, the system was also integrated with a cyclone, a water scrubber, and a carbon‐bed filter. Biomass was fed at a rate of 5 kg/h, while the air equivalence ratio (ER) and the gasification temperature were set at 0.1 and 800°C, respectively. In total, 5 kg of the specially developed low‐cost Fe/activated carbons (AC) catalyst was used in the hot gas catalytic tar‐cracking reactor. Results indicate that our integrated gasification system was able to produce a clean burnable gas with a lower heating value (LHV) of 9.05 MJ/Nm3, carbon conversion efficiency (CCE) of 79.4%, cold gas efficiency (CGE) of 89.9%, and H2 and CH4 concentrations of 29.5% and 10.3%, respectively. The final outlet gas was found to only contain 32.5 mg/Nm3 of tar, thus making it suitable for internal combustion engine (ICE) application. [ABSTRACT FROM AUTHOR]

Abstract: The reduction of solid metal oxide by hydrogen or hydrocarbon gases represents a class of reactions that are important to various technological applications. This study investigates the reduction of unsupported NiO nanoparticles and silica-supported NiO with different reducing gases (hydrogen, methane and ethane) in the temperature range of 500–600°C. It was found that, in addition to the reaction and mass transfer of molecular species, the fates and activities of surface-formed radical species have to be considered in explaining the kinetics of nickel oxide reduction. It is believed that the desorption of hydrocarbon radicals from the particle surface has significantly slowed down the reduction of unsupported NiO nanoparticles. The ease with which a radical migrates from its generation site on a metallic island to the Ni–NiO surface boundary, on the other hand, is an important rate-determining factor in the reduction of silica-supported NiO. [Copyright &y& Elsevier]