Bio-syngas production from biomass catalytic gasification

Abstract

A promising application for biomass is liquid fuel synthesis, such as methanol or dimethyl ether (DME). Previous studies have studied syngas production from biomass-derived char, oil and gas. This study intends to explore the technology of syngas production from direct biomass gasification, which may be more economically viable. The ratio of H 2 /CO is an important factor that affects the performance of this process. In this study, the characteristics of biomass gasification gas, such as H 2 /CO and tar yield, as well as its potential for liquid fuel synthesis is explored. A fluidized bed gasifier and a downstream fixed bed are employed as the reactors. Two kinds of catalysts: dolomite and nickel based catalyst are applied, and they are used in the fluidized bed and fixed bed, respectively. The gasifying agent used is an air-steam mixture. The main variables studied are temperature and weight hourly space velocity in the fixed bed reactor. Over the ranges of operating conditions examined, the maximum H 2 content reaches 52.47 vol%, while the ratio of H 2 /CO varies between 1.87 and 4.45. The results indicate that an appropriate temperature (750 °C for the current study) and more catalyst are favorable for getting a higher H 2 /CO ratio. Using a simple first order kinetic model for the overall tar removal reaction, the apparent activation energies and pre-exponential factors are obtained for nickel based catalysts. The results indicate that biomass gasification gas has great potential for liquid fuel synthesis after further processing.