Gasification of biomass as green energy technology: Evaluation and characterization of biomass in a downdraft gasifier for lab-scale

In the current study, a biomass gasification process by air was proposed. Investigastion of municipal solid waste (MSW) as biomass in a downdraft gasifier indicated that under the optimum operating conditions, a fuel gas could be produced with a production rate of about 2.0 Nm3/kg biomass and heating value of about 3500 kJ/Nm3. Gasification is a process that converts carbonaceous materials (coal, biomass, organic waste) into carbon monoxide and hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen and/or steam. The challenges with gasification are to understand the effects of operating conditions on gasification reactions for reliably predicting and optimizing the product compositions, and for obtaining maximal efficiencies. Product gases can be converted to biofuels and chemicals such ad green gasoline, hydrogen, dimethyl ether, ethanol, methanol, and higher alcohols.The main product of the gasification process is syngas, which contains carbon monoxide 10.50%, hydrogen 10.25% and methane 5.50%. The system carbon conversion and cold gasification efficiency reached above 75% and 65%, respectively. The tar formation could be efficiently controlled below 9 mg/Nm3. In addition, the heating value of product fuel gas was 7500 kJ/Nm3.

Keywords:

Gasification , Biomass , Downdraft , Syngas