Electrostatic precipitators cold-side

Plant description. Two nearly identical 430-Mw(e), western, conventional pulverized-coal-utility boilers (referred to as plants A and D) were tested. Both units use tangentially fired burners and burn low-sulfur 200-mesh coal of heat content approximately 27 000 J/g. Both units are equipped with cold-side electrostatic precipitators (ESP) of design efficiency of 99.5% or greater, and a modern flue-gas desulfurization (FGD) system consisting of four verticle spray towers. 

Table II. Estimates of the concentrations of selected elements in submicrometer-diameter particles collected upstream of a cold-side electrostatic precipitator, ppm.

To do this, the paper first explained the operation of existing particulate control devices, notably the electrostatic precipitator (ESP). It described how particulate capturability can be improved by chemical treatment and then illustrated how proprietary formulation has led to the treatment of a wide variety of fuels in both cold and hot side ESP units. Evidence was also presented showing fine particulate emissions, i.e., those implicated in health effects, could be significantly reduced. A description was made of the specific marketing problems that had to be solved when a chemical company sought to develop an industrial market where the customer has little or no chemical capability. 

The particulate removal device, such as an electrostatic precipitator, can be placed either before the air preheater (a hot-side electrostatic precipitator) or after the air preheater (cold-side electrostatic precipitator). A fabric filter can be used in place of the electrostatic precipitator. Alternatively, or in addition, a flue-gas-desulfurization (FGD) unit treats the hot gas before it is released to the atmosphere. 

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