Physical and chemical characterization of the process stream for a commercial-scale fluidized-bed combustion boiler

PAH Emissions from the Fluidized-Bed Incineration of an Industrial Sludge

“…9 Naphthalene was the only PAH reported in the study. Yeh et al 4 characterized the vapor-phase and particle-associated PAHs in the flue gases with the combustion of anthracite culm in an atmospheric pressure fluidizedbed combustor with a bed size of 3.34 square meters. Their culm contained less than 6% surface moisture, had a heating value of 3,900 kcal/kg, and was burned at approximately 815-905 °C.…”

“…Furthermore, most of these studies were carried out under fuel-lean conditions at normal operating temperatures, due to the impracticality of variation of the experimental parameters in a large-scale facility and the necessity of maintaining normal operation, as required by the owners. 2,4,8,9 The objective of this study, therefore, was to systematically examine the effects of temperature and equivalence ratio upon the PAH emissions from a laboratory-scale fluidized-bed incinerator. The burnt waste was a sludge from a wastewater treatment plant located in a general industrial park.…”

“…The nominal gaseous residence time in the incinerator was then calculated to be in the 0.7-1.2 second range, which was rather short compared with previous studies. [1][2][3][4]9,11,12 Analysis The samples collected from the flue gases were then extracted in Soxhlet with dichloromethane (DCM), concentrated in a rotary evaporator, cleaned through an eluting column (packed with silica gel and activated alumina), re-concentrated in the rotary evaporator, and, finally, quantitated to a volume of 1.0 mL. Aliquots of these concentrates were then injected into a GC/FID for qualitative and quantitative analyses.…”

“…2,4,8,11 Such a high level of PAH emissions may be caused by the vaporization of the priority PAHs, which were in high content in the sludge, and by poor incineration conditions. The poor incineration conditions were caused by a short residence time of 0.7-1.2 seconds, a relatively low percentage of excess air (or even by being intentionally operated under fuel-rich conditions), and a low or medium incineration temperature.…”