Power Plant's Conversion to Low Sulfur Coal Required New Method to Increase Efficiency of the Electrostatic Precipitator
 Employing Steam Was Less Costly Than Compressed Air
Today, many utilities and coal fired power plants are converting from high sulfur coal to low sulfur coal. However, this conversion process can affect the exit gas opacity limits that are strictly monitored by the Environmental Protection Agency (EPA).
PROBLEM: This electric utility plant in Indiana was in the process of converting to low sulfur coal. In order to increase the efficiency of the electrostatic precipitator, water is mixed with air and sprayed into the flue gas. This process, which decreases the temperature and increases the humidity, ultimately reduces the resistivity of the particulates contained in the gas.
However, this particular facility did not have an air compressor and would have had to purchase one for the humidification process.
SOLUTION: Instead of air, Spraying Systems Co. recommended using steam, which is obviously in abundant supply at the facility.
Six, FloMax® air atomizing, dual nozzle lance assemblies combine the steam and soften filtered river water for evaporation purposes. The dual nozzle lance assemblies are fed by various liquid and steam lines with separate manual shut-off valves and pressure gauges.
Although special materials of construction are available for higher temperature applications, the FloMax air atomizing nozzles were specified in 316 stainless steel, ideal for this application since the gas temperatures average 330°F (116°C).
The facility has five ducts that run from the boilers to the electrostatic precipitator. Eventually they plan on adding FloMax air atomizing dual nozzle lance assemblies to all five.
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