Effects of Species, Specimen Size, and Heating Rate on Char Yield and Fuel Properties
Keywords:Pyrolysis, char, gross heat of combustion
Char yields from red maple, white oak, longleaf pine, and hybrid poplar (NE 388) wood specimens of four different particle sizes carbonized in a flowing nitrogen atmosphere with heating rates of 5, 15, and 25 C/min up to 250 C, 400 C, and 600 C were examined. Although species, particle size, and heating rate trends were evident, regression analysis showed final carbonization temperature to be the most important factor influencing char yield.
Carbonized and noncarbonized specimens were subjected to elemental analysis and gross heat of combustion determinations. Regression analysis established a significant relationship of carbon and hydrogen content with final carbonization temperature. A linear relationship was found between gross heat of combustion values and carbon contents of wood and char specimens. An equation to theoretically calculate gross heat of combustion values of wood and char was developed through modification of Dulong's formula.
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