In order to study the incineration method of insulating oil contained small amount of PCBs (ND-50ppm), combustion test was conducted by using combustion facility which had flue gas treatment equipment's to keep safety supervision and environmental protection. Two type of operating condition was selected. The one was to assumed to actual boiler's condition including air heater and electrostatic precipitator. Another was assumed to the operating condition for the exclusive use of incineration of insulating oil contained PCBs. As a result, it was proved that the small amount of PCBs contained in insulating oil could be decomposed by the incineration method using spray combustion if high combustion temperature and long residence time should be kept in furnace. Moreover PCDDs was not detected at the exit of boiler flue and at the exit of afterburning furnace.
Effect of co-existing SO2 on the catalytic activity of Sn supported alumina catalyst was investigated for the reduction of NO in the presence of high concentrations of oxygen and water vapor. Although the catalytic activity decreased at the initial stage of the activity test in the presence of SO2 over Al2O3, Sn/Al2O3 and Co/Al2O3, a stable NO conversion was observed afterwards. The steady state catalytic activity was in the order of Sn/Al2O3 > Co/Al2O3 > Al2O3. The catalytic activity of Sn/Al2O3 for NOx reduction in the low temperature region was increased with increasing Sn loading. 5 wt%Sn/Al2O3 showed the highest activity among Sn supported alumina catalysts. The accumulation of sulfur was observed on the spent catalyst, and its amount was closely related to the co-existing SO2 concentration and NOx conversion level. XPS and IR spectra measurements suggested the formation of Al2 (SO4) 3-like species on the catalyst surface. The efficiency of the reducing agent was in the following order methanol > ethanol > propylene > propane. In particular, methanol reduced NO most effectively on Sn/Al2O3.