Fluidized bed gasification of wood chips using bottom ash derived from coal: optimization of operating conditions

Abstract

ABSTRACT Although biomass gasification is well recognized as a practical method for producing syngas, the generated gas cannot be used in a variety of applications because of technological issues like tar formation. In this research, coal bottom ash (CBA) was used as an in-bed material for the experimental examination of biomass (wood chips) gasification in a fluidized bed system. All tests were conducted at reaction temperatures between 750 and 900 C, steam to biomass ratios between 0.24 and 0.96, CBA particle sizes between 0.22 and 1.2 mm, and biomass particle sizes between 0.5 and 3.0 mm. The primary objective of this research is to use an experimental set-up to assess the effectiveness of steam gasification of biomass using CBA with various particle sizes. The findings showed that using steam as a gasification agent and raising the temperature improved tar cracking and H2 generation. The findings also demonstrated that the catalyst particle size is efficient for H2 production and that CBA can be used as an in-bed material for the production of H2-rich syngas. Under an 850°C reaction temperature, a S/B of 0.96, a CBA size of 0.2–0.4 mm (Case I), and a biomass particle size of 0.5–1.2 mm, the H2 concentration achieved a maximum of 65.7 vol%. (Case I).