Numerical Analysis on Biomass Gasification in a Fluidized Bed Gasifier

Abstract

Several methods are offered for production of hydrogen. One of the most common method of hydrogen production is biomass gasification using fluidized bed gasifier. Biomass gasification is defind as a process that converts the organic fuel based carbonaceous materials into CO2, H2, CO. The complete process is carried out by reacting the feedstock at very high temperature (> 900 °C), without combustion, by providing a controlled amount of O2 and/or steam. The product coming out from the process is known as syngas or producer gas, which is also used as a fuel.
The present work aims to produce of syngas/ rich gas from feedstock material rice husk using a fluidized bed gasifier. The pilot plant of the gasifier is modelled using ASPEN PLUS commercial software. The performance studies on the hydrogen production by varying the operating condition. The effect of various operating parameters such as temperature, equivalence ratio, steam to biomass ratio and particle size on the proportion of syngas, hydrogen yield and carbon conversion efficiency. The bed material used in the present work within the pilot plant gasifier is silica sand. The gasifier operating temperature varied from700 to 900 °C, the equivalence ratio from 0.19 to 0.25 and biomass ratio is also varied from 0.5- 1.5. The hydrogen production from the gasifier is compared with all the operating parameters. The numerical results are compared with the experimental data (reported) available in the literature, and observed and agreement. It is observed that the hydrogen concentration in the syngas composition increases with increase in temperature and steam to biomass ratio, where as it decreases with increase in equivalence ratio.