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pp.78-84
Waste heavy oil sludge is considered oil waste that can be utilized as a renewable energy source. In this study, an attempt has been made to convert the mixtures of waste heavy oil sludge and sawdust into solid biomass fuels. The solid fuel pellets from waste heavy oil sludge and sawdust could be manufactured only with a press type pelletizer. The mixing ratios of waste heavy oil sludge and sawdust capable of manufacturing a solid fuel pellet were 30 : 70, 40 : 60 and 50 : 50. Ultimate analysis result revealed that these mixtures had C 50.21 ~ 54.77%, H 10.25 ~ 12.66%, O 25.84 ~ 34.83%, N 1.01 ~ 1.04%, S 1.03 ~ 1.07%. With increasing the mixing ratio of waste heavy oil sludge, the carbon and hydrogen content in solid fuel pellets were increased, while the oxygen content was decreased. But the nitrogen and sulfur content in solid fuel pellets did not show much difference. Their lower heating values ranged from 4,780 kg/kcal to 5,530 kg/kcal. The density of the solid fuel pellets was increased from 0.63 g/cm3 to 0.85 g/cm3 with increasing the mixing ratio of waste heavy oil sludge and the collapse of the solid fuel pellets occurred at a moisture content of 21%. As the mixing ratio of waste heavy oil sludge in the solid fuel pellets was increased, the reaction of thermal cracking became faster. It was also observed that the solid fuel pellets were thermally decomposed in two steps and their DTG curves were simpler with increasing the mixing ratio of waste heavy oil sludge. The activation energy and the pre-exponential factor of the solid fuel pellets ranged from 18.90 kcal/mol to 21.36 kcal/mol and from 201 l/sec to 8,793 l/sec, respectively. They were increased with increasing the mixing ratio of waste heavy oil sludge.
