Modeling of Biomass Gasification to Syngas

Methanol and ethanol are the alternative fuels to gasoline in the future for they combust cleanly. Synthesis of them from biomass is an attracting and challenging subject. Much effort had been done to synthesize methanol by catalysts from H2 and CO，especially when the ratio of H2 to CO is 2 : 1（Syngas）. So if the Syngas can be obtained from biomass gasification the route of biomass to liquid fuels will be simple. The purpose of the thermodynamics modeling of biomass gasification reported here is to study the optimal condition for Syngas production. A program named FBGB was written by PASICAL and DELPHI based on materials balance，energy balance and chemical reaction balance in the gasifier. There are several variable parameters such as the biomass component，the quantity of air，the velocity of input materials，and the temperature in the gasifier which can be input. After calculation of fifteen values such as the quantities of the product gases，both the heat values of the product gases and tar can be obtained. Using the program，the relationship of biomass input velocity，the steam input velocity and the component of product gas is simulated，and it is found that the ratio of input velocity of steam to input velocity of biomass（S / B）is the key factor to the ratio of H2 to CO. When other conditions are fixed，the ratio has a direct proportion relationship to S / B. By adjusting S / B the ratio of H2 to CO can be controlled to 2 : 1，which is suitable to synthesize methanol. The comparision of the experimental results proves the validation of the modeling and the program.