Flue gas particulates

Where low-grade coal is burned, electrostatic precipitators or fabric filters may be required for flue-gas particulate collection and a wet desulfurization system (gas scrubbers) to remove sulfur from the flue gas. 

To prevent damage to downstream equipments and poisoning of downstream catalysts, the following contaminants have to been removed from the flue gas particulate (ash, char, and fluid bed material) causing erosion, alkali metals (sodium and potassium compounds) responsible for hot corrosion, tars (high molecular weight hydrocarbons and refractory aromatics), and catalyst poisoning species (H2S, HC1, NH3, and HCN). 

The actual particulate emission rate is the product of the stack flowrate and the stack flue gas particulate concentration. The stack flowrate is calculated from the velocity measurements provided in the problem statement using the second velocity equation given ... 

The CO, combustion produced particulates, and the unbumed hydrocarbons are all related to the amount of excess air, type of fuel, and the amount of mixing of the fuels within the burner. Insufficient air and inadequate mixing can result in incomplete combustion thus raising the amount of CO and unbumed hydrocarbons in the flue gas. Particulates formed in the combustion process are very low for gaseous fuels but will increase with the use of liquid fuels. 

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