Page 8 - dust collection systems

A sudden drop in the differential pressure denotes a leak in
the system. Whereas a sudden or sharp rise in the differential

pressure denotes that the filter bags are becoming blinded or

“caked” with particulate. Hence the differential pressure

gauge is the best indicator of baghouse’s current operating

status, and offers critical information for troubleshooting.

Advantages and Disadvantages of Fabric Filters

Fabric filters in general provide high collection efficiencies on

both coarse and fine (submicron) particulates. They are

relatively insensitive to fluctuations in gas stream conditions.

Operation is relatively simple. flammable dust may be

collected with proper care. Fabric filters are useful for

collecting particles with resistivities either too low or too high

for collection with electrostatic precipitators. Fabric filters

therefore may be good candidates for collecting fly ash from

low sulphur coals or fly ash containing high unburned carbon

levels, which respectively have high and low resistivities, and

thus are relatively difficult to collect with electrostatic

precipitators.

However, there are gas temperature limits to the application

of fabric filters because of the limits of the fabric itself. At

high temperatures, the fabric can thermally degrade, or the

protective finishes can volatilize. Accordingly, fabric filters
have usually been limited to gas temperatures below