Emission potential of condensable suspended particulate matter from flue gas of solid waste combustion

Condensable suspended particulate matter, condensable SPM, is generated during the cooling process of flue gas by mixing with the atmosphere. Condensable SPM from stationary sources, such as power plants, waste incinerators and factories, is rather difficult to evaluate since dust sampling from exhaust gas is usually performed downstream of dust collectors, which are maintained at relatively high temperatures. In this study, in order to discuss the emission mechanism of condensable SPM from waste incinerators, model flue gas comprised Cd and Pb was produced by the sublimation of pure CdCl2 and PbCl2 in gas stream. Model flue gas was cooled in a diluter after separation of particulates by a bag filter kept at operational temperatures common to commercial plants. Particle size distribution of generated condensable SPM after a diluter was measured by a differential mobility analyzer (DMA). The composition of the model gases was determined based on our experiments carried out on fueled refuse derived fuel (RDF) in a laboratory-scale fluidized bed combustor. The effect of the CdCl2 and PbCl2 sublimation temperature, filtration temperature, and bag filter ash layering on the resulting particle size distribution of SPM was examined. The emission possibility of condensable SPM from solid waste incinerators is discussed based on experimental results and thermodynamic calculation.

Graphical AbstractIn order to examine the possibility of emission of Cd and Pb compounds from waste incinerators in the form of condensable suspended particulate matter, model exhaust gas was generated by the sublimation of CdCl2 and PbCl2, introduced through a bag filter and diluted by the direct air cooling method. Particle size distribution of the exit gas was measured by the DMA. Particle size distribution of model exhaust gas containing sublimed CdCl2 at 450°C. Filter temperature was 150°C.Figure optionsDownload as PowerPoint slide