Gasification of rice straw in an updraft gasifier using water purification sludge containing Fe/Mn as a catalyst

• The Fe/Mn sludge has been developed as a potential catalyst in gasification.
• The heating value of combustible gas increased with an increase in Fe/Mn sludge addition.
• The heating value of combustible gas increased from 14.76 MJ/Nm3 to 15.82 MJ/Nm3.
• Maximum energy density of combustible gas was approximately 1.49.

This study investigated the feasibility of gasification of rice straw using an Fe/Mn sludge as a catalyst. The Fe/Mn sludge contained iron and manganese compounds produced from a water purification plant. The gasification temperature and equivalent ratio (ER) was set at 900 °C and 0.30, respectively, with an amended catalyst ratio of 0%–15%. Experimental results indicated that the combustible gas production was increased from 0.61 m3/kg to 0.72 m3/kg with the Fe/Mn sludge addition. The lower heating value (LHV) of combustible gas and energy density (ED) were also increased with an increase in Fe/Mn sludge addition. The LHV and ED increased from 14.76 MJ/Nm3 to 15.82 MJ/Nm3 and from 1.37 MJ/MJ to 1.47 MJ/MJ, respectively. In conclusion, the catalytic gasification of rice straw was more efficient on an energy yield basis with the Fe/Mn sludge addition. The Fe/Mn sludge used in this research has been developed as a potential catalyst for the application of rice straw gasification.