High Stack Opacity

Coal Fineness Effect on Boiler Emissions

Non-optimum coal fineness can lead to emission complications such as higher than desired or non-repeatable NOx
emissions, high particulate emissions, high Carbon Monoxide emissions or high opacity. Increased coal fineness
will result in more repeatable NOx emissions and lower CO emissions. High flyash unburned Carbon will increase
particulate emissions and opacity. It is a well known fact that the collection efficiency of electrostatic precipitators is
decreased as flyash carbon content increases. For this reason many boilers fail particulate emission tests or exceed
stack opacity limits due to high flyash LOI caused by poor fineness. Fineness can also affect ignition points & flame stability. Combined effects of fuel balance, fineness, ignition points & flame stability will result in non-uniform
combustion and furnace temperatures.