Optical measurement of PM-relevant emissions
J. Binnig, J. Meyer, G. Kasper
FILTECH 2005 International Conference & Exhibition for Filtration and Separation Technology, 11.-13.10.2005, Wiesbaden, Germany, Proceedings, II 94-101
Bag-house filter systems are standard devices used for gas cleaning in large scale applications. The filter media used in such systems are known to have very low emissions, therefore standard screening tests focussed on the operation behaviour rather than on the emissions. Facing the increasing interest in PM-relevant immissions, a more detailed description of such sources of fine particles is of urgent importance. However, the standard gravimetric method used for immission measurement is not suitable for standard screening tests of surface filter media, as long measurement times are needed due to the low emission and the transient behaviour of a surface filter system cannot be displayed.
Therefore, an optical particle counter (OPC) has been used for the measurement of the emissions of surface filters during standard screening tests. The method delivers an optical diameter and particle number concentration instead of aerodynamic/gravimetric rating specified on the PM-standards, therefore calibration is needed to derive the PM-mass concentration from the data obtained by the OPC.
The authors have conducted a PM2.5-calibration for Pural SB as particle material and used the specially calibrated OPC in a large series of filter tests. As a reference method, a BGI sharp-cut cyclone (SCC) was used for direct PM2.5 measurement. The OPC results were found to possess an accuracy of ±20% when compared to the SCC reference data.