STEAM GASIFICATION OF MISCANTHUS IN A DOUBLE STAGE DOWNDRAFT GASIFIER

摘要

Gasification is the incomplete combustion of biomass, which produces syngas, biochar and tar. A study of steam gasification of Miscanthus was done on a double stage down draft gasifier at Federal University of Itajuba. The main objective of this paper is to analyze and characterize the syngas produced from the double stage downdraft system. Compared to the previous publication that focused on the gasification of corn using air, this paper elaborates on the steam gasification of Miscanthus. In a double stage downdraft gasifier, Miscanthus with 12% moisture was inserted into the system from the top. The gasifier has two inlets: primary and secondary. The steam was inserted through these inlets. The Miscanthus briquettes entering the gasifier were passed through a drying zone where the moisture content was removed. The fuel was then passed through a combustion and pyrolysis zone followed by a reduction zone. The syngas produced exited the gasifier through a grate and was analyzed for a continuous period of time. When using steam as a gasifying agent, it was found that the syngas showed a 15 % increase in hydrogen, a 50% decrease carbon monoxide with no change in methane composition. The increase in hydrogen can be used for alternate energy such as in fuel cells. The syngas heating value was obtained to be 4.64 MJ/Nm~3. This paper compares the syngas composition evolved from the gasification of Miscanthus when using air and steam as gasifying agents.