Pollutants And Control Techniques Of Industrial Boiler
Industrial boilers are a necessary equipment for industries. But combustion of fossil fuels industrial boilers results in environmental pollution, particularly in coal fired boilers. The emissions such as carbon monoxide, nitrogen oxide, sulfur oxides, volatile organic compounds, and particulate matter are considered pollutants and are known to, either directly or indirectly, cause harmful affects on humans and the environment.
NOX control techniques
NOX control includes post combustion methods and combustion control techniques. Post combustion methods address NOX emissions after formation while combustion control techniques prevent the formation of NOX during the combustion process. Combustion control techniques are more economical than post combustion methods and are frequently utilized on industrial boilers. Post combustion control methods include selective non-catalytic reduction and selective catalytic reduction. Combustion control techniques include low excess air firing, low nitrogen fuel oil, burner modifications, water/steam injection, flue gas recirculation.
Sulfur compounds control techniques
Methods of SOx reduction include switching to low sulfur fuel, desulfurizing the fuel, and utilizing a flue gas desulfurization (FGD) system. For users of industrial boilers, utilizing low sulfur fuels is the most cost effective method of SOx reduction. Because SOx comes from the sulfur content of the fuel, burning fuels containing a minimal amount of sulfur (distillate oil) can achieve SOx reductions, without the need to install and maintain expensive equipment.
Carbon monoxide control techniques
High levels of carbon monoxide emissions mainly owing to incomplete combustion due to poor burner design, firing conditions or possibly a leaky furnace. Through proper burner maintenance, inspections, operation, or by upgrading equipment or utilizing an oxygen control package, the formation of carbon monoxide can be controlled at an ideal level.
Particulate matter control techniques
Emissions of particulate matter (PM) from combustion sources including nitrates, sulfates, carbons, oxides, and any uncombusted elements in the fuel. Particulate pollutants can be corrosive, toxic to plants and animals, and harmful to humans. The most effective method is to utilize clean fuels for industrial boilers. The emission levels of particulate matter can be decreased by switching from a residual to a distillate oil or by switching from a distillate oil to a natural gas. Besides, through proper burner set-up, adjustment and maintenance, particulate emissions can be minimized, but not to the extent accomplished by switching fuels.
