Minimizing Rapping Loss in Precipitators At a 2000-Megawatt Coal-Fired Power Station

Abstract

Present trends toward larger plants have forced precipitator manufacturers to use collecting electrode plates 30 feet high routinely. After the dust suspended in the gas has been precipitated on these tall plates, it is necessary to transfer it continually to the hoppers underneath, losing less than 1% of it to the gas stream (and hence up the stack) in the process, if dust loss is to be kept below 1%. This is done by striking or vibrating the plates with devices called “rappers,” operated sequentially by controls programmed to any desired sequence, rapping intensity, and repeating time interval.