Fibre selection for dust collection

Because of the wide diversity of thermal and chemical conditions that prevail in dust collectors, the correct choice of fibre type is the most fundamental of all considerations when designing or selecting the filter fabric. A selection of the more common fibre types that are used in dust collection and their properties is shown in Table 7.2. 

Fibre type Trade names Maximum Resistance to  

E = Excellent, VG = Very Good, G = Good, F = Fair, P = Poor. 

On the other hand the combustion of fossil fuels in general creates yet another complication, due to the formation of combustion products such as oxides of sulphur (SOx), and nitrogen (NOx), which in the presence of moisture can lead to highly acidic conditions. In certain circumstances, SO3 may be 

Unfortunately, the maximum temperature (190°C) at which this fibre can continuously operate is somewhat lower than the previous hbres, and if the oxygen content of the gas stream were also high, e.g. 15% or more, degradation due to thermal oxidation could be expected, thus reducing the maximum operating level still further. The presence of bromine as found in certain coals is also known to have a deleterious effect on this hbre. 

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Chromium speciation is very often performed in workplace air and a careful selection of the filter medium used for collecting dusts is of paramount importance. Cellulosic filters and glass fibre filters containing binders are ordinarily unsuitable, as these filter types can lead to significant reduction of Cr(Vt). Filter materials acceptable for sampling of airborne Cr(VI) include PVC, PVF, PTFE or quartz fibre filters. ... 

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