Experimental Investigation of Downdraft Gasifier Using Different Biomass Fuels

Abstract

In a study, methane and carbon dioxide were generated through downdraft fixed-bed gasification, converting rice husks, waste plastic, and sawdust. The heat potential in biomass is crucial for synthetic gas production, and waste plastic, with the highest heating value at 40 MJ/kg, offers superior potential for high hydrogen concentration in synthetic gas (3-18% by volume) compared to rice husk and sawdust. Rice husk yields lower hydrogen and methane concentrations than sawdust. Gasification efficiency and output depend on the gasifier type, with downdraft fixed-bed gasifiers being highly effective. The gasification process's outcomes rely on factors like reactor temperature, catalyst exposure time, residence time, and catalyst heating temperature. This process transforms biomass into synthetic gas, which can power internal combustion engines and facilitate cogeneration for both electricity and heat. Biomass gasification shares similarities with coal gasification, yielding similar by-product gases during thermal breakdown but with less stringent operating requirements. Rice husk, waste plastic, and sawdust are fed into a downdraft fixed-bed gasifier, and synthetic gas is collected at the exhaust end. Analysing synthetic gases involves gas analysers, and this gas can drive engines, boilers, and machinery. Additionally, a MATLAB code snippet integrated into a Gasifier simulation GUI application enables users to visualize performance metrics, aiding understanding and optimization of gasifier dynamics for educational and practical purposes.