Modeling of Biomass Gasification with Preheated Air at High Temperatures

Effects of reaction temperature, moisture content, and preheated air temperature on biomass gasification performance such as syngas composition, cold gas and 2nd law efficiencies, and caloric value, were studied based on a thermodynamic equilibrium model. The results indicated that the contents of the combustible species (H2, CO, and CH4) in the product syngas control the gasification performance. Less amounts of combustible species were resulted for the conditions of high reaction temperature, high moisture content, and low preheated air temperature. Using H2 content as a reference, there appears an optimum reaction temperature. With biomass moisture content exceeding a certain amount, reduction in combustible species was found. Although the gasification performance can be enhanced by using preheated air, the degree of improvement is not significant even for air with high temperature.