Influence of leaks on the overall emission behaviour of bag house filters
O. Kurtz, J. Meyer, G. Kasper
FILTECH 2015 International Conference & Exhibition for Filtration and Separation Technology, Cologne, 24.-26.02.2015, Abstracts G1
Recent research regarding the emission behaviour of bag house filters has shown that clean gas concentrations of well below 1 mg/m3 can generally be achieved with high-quality needle felts in an well-designed pilot scale filter rig under normal operating conditions . On the other hand, actual emissions from industrial filter houses typically exceed those levels, often by an order of a magnitude or more. This brings up two questions: What causes these differences, and what kind of emission performance can one expect realistically in an industrial environment?
The presentation will show that the differences are largely due to leaks between clean gas and raw gas side. It is based on experiments performed on a laboratory scale filter unit with 9 bags made of high-quality (but nevertheless standard) needle felt.
A first part of the presentation will show the effect of defined leaks placed deliberately in the filter media and the head plate. The influence of various operating parameters on the leakage will be discussed.
Next, a method will be described to separate the cyclical dust emissions caused by the “normal” operation of filter bags from the emissions caused by additional leakage. This method is based on time-resolved on-line measurements with optical particle counters. Due to a special calibration  these OPCs can express the dust concentration in terms of PM2.5 mass.
Based on this method, the contribution of leaks to the overall dust concentration in the clean gas will be discussed and estimates will be made with regard to the performance of leakage free bag house filters.