What is Flue Gas Humidification and Conditioning for Power Plants?
In hundreds of industrial and utility power plants, coal is burned to produce steam. The steam is used in heating and/or electrical generation, in which the steam drives a turbine/generator unit. However, coal-fired boilers result in high fly ash resistivity, which can cause high opacity, and excess sulfur trioxide (SO3) emissions, which can cause blue or brown plumes. When coal-fired boilers are used, a certain percentage (<10% to >30%) of the coal is ash, mostly silica, alumina and iron oxides. Some of the ash is light enough to be carried out of the boiler and eventually out of the stack. This light ash is called “fly ash”, which flies away and doesn’t drop out of the flue gas stream, as does “bottom ash”. Fly ash emissions are controlled by either bag houses or electrostatic precipitators (ESP’s). ESP’s are large electrical devices that use high voltages to electrostatically charge the fly ash and cause it to precipitate out of the flue gas stream. The collection efficiency of the
