Bag filter performance is dependent upon inlet and outlet gas temperature, pressure drop, opacity, and gas velocity. The chemical composition, moisture, acid dew point, and particle loading and size distribution of the gas stream are essential factors as well. Gas temperature – Fabrics are designed to operate within a certain temperature range. Fluctuation outside of these limits, even for a small period of time, can weaken, damage, or ruin the bags. Pressure drop –bag filters operate most effectively within a certain pressure drop range. This spectrum is based on a specific gas volumetric flow rate. Opacity – Opacity measures the quantity of light scattering that occurs as a result of the particles in a gas stream. Opacity is not an exact measurement of the concentration of particles; however, it is a good indicator of the amount of dust leaving the bag filters. Gas volumetric flow rate –bag filters are created to accommodate a range of gas flows. An increase in gas flow rates causes an increase in operating pressure drop and air-to-cloth ratio. These increases put more mechanical strain on the bag filters, resulting in more frequent cleanings and high particle velocity, two factors that shorten bag life.
