Fly-ash Collection

the process of removing fly ash from stack gases. Fly-ash collection is effected by mechanical or electrical equipment (ash separators). In dry mechanical ash separators (blocks of cyclone separators, battery cy-clone separators, and louver ash separators), ash is collected by centrifugal force when the gases change direction of motion. In wet mechanical ash separators (scrubbers), improved purification is obtained by spraying into the gases water atomized by sprinkler jets; the collected ash is washed off by a film of water. Electrostatic precipitators make use of the attraction between negatively charged dust particles and positively charged precipitating electrodes. The maximum purification (up to 99 percent) is obtained by placing in series mechanical ash separators and electrostatic precipitators.