2012 Volume 91 Issue 2 Pages 111-117
The reduction of fluoride emissions from coal combustions is important to reduce fluoride pollution in the atmosphere. It has been suggested that biobriquettes can be used for both desulfurization and defluorination. In this study, effects on defluorination from two biobriquettes were examined. One of the biobriquettes was made by mixing powdered coal, powdered bamboo and Ca(OH)2. The other biobriquette was made by mixing powdered coal, and powdered bamboo covered by Ca(OH)2. The molar equivalency of Ca to (F2 + S) was 2 in both of the biobriquettes. The combustion temperature of the furnace was 600 °C - 900 °C. The results showed that both of the biobriquettes have high efficiencies on defluorination of coal, and the efficiency of the one made with bamboo covered by Ca(OH)2 is higher. The defluorination efficiency increases with decreasing temperature. The concentration of SO2 emitted from the biobriquettes made with bamboo covered by Ca(OH)2 is lower at the same combustion condition. This study shows that biobriquettes are promising for defluorination of coals.