A boiler is a closed vessel in which water or other fluid is heated. The heated or vaporised fluid exits the boiler for use in various heating processes or applications, including power generation in which pressurised steam is used to revolve a turbine, and heating for use as a reactant or diluent in a production vessel, or heating for building air conditioning.
The boiler’s burner burns the fuel fed together with air to generate steam. It is necessary to regulate the air/fuel mass in order to maintain a constant ratio of the mixture.
In actual applications, however, steam loads can vary significantly and unpredictably over time. Either air or fuel flow may be delayed in tracking such changes, resulting in a temporary imbalance of the air/flow ratio.
Too much fuel or air can cause environmental and safety problems and reduce the energy efficiency of the boiler.
Insufficient air leads to unburned fuels (fuel, soot, smoke and carbon monoxide), while too much air leads to heat loss due to increased flue gas flow, which reduces the overall efficiency of the boiler in terms of fuel-to-steam ratio.
