Читать книгу Encyclopedia of Renewable Energy - James Speight G., James G. Speight - Страница 127

Baghouse fabric filters are generally used where higher removal efficiency is required for particles smaller than approximately 10 microns. Thus, the filter is an air pollution control device and dust collector that removes particulates or gas released from commercial processes. A large number of bag-shaped filters would be needed to clean large gas flows. In general, all of the filters would be enclosed in the same structure (a baghouse) and would share input and output gas manifolds.

As a gas stream passes through the baghouse, dust is removed by one or more of the following physical phenomena: intersection, impingement, diffusion, gravitational settling, or electrostatic attraction. The initial filtration creates a layer of dust on the bag fabric. This layer is primarily responsible for this method’s high removal efficiency; the filter cloth serves mainly as a support structure.

The efficiency of a baghouse filter depends on the particle size distribution, the particle density and chemistry, and moisture. Under most conditions, a well-designed and well-operated baghouse will achieve a removal efficiency of at least 99% for particles as small as 1 micron. In the renewable energy industry, baghouse filters are likely to be used for dust removal from crushers, screens, transfer points, and storage bins.

Fabric life may be substantially shortened in the presence of high acid or alkaline atmospheres, especially at elevated temperatures; also, the maximum operating temperature is limited to 285°C (550°F), unless special fabrics are used.

See also: Baghouse, Centrifugal Separation, Cyclone Separation.