Which of the following are released significantly during combustion of coal ?…

Concept

Coal combustion can emit particulate matter from incomplete burning and from the mineral fraction that does not burn.

Soot is carbon-rich particulate matter, fly ash is the fine mineral residue carried with flue gas, and sulfur can occur in sulfate-bearing particulate matter. Nitrate is generally a secondary product of nitrogen oxides, while ammonia is not a characteristic coal-combustion product.

Application

• Soot is associated with incomplete combustion of the carbonaceous part of coal.

• Sulfate can occur in coal-combustion particulate matter after oxidation of sulfur compounds.

• Nitrate is not a significant direct coal-combustion particulate emission; it usually forms secondarily from nitrogen oxides in the atmosphere.

• Fly ash is the fine, non-combustible mineral residue entrained in the flue gas.

• Ammonia is not normally a significant product of conventional coal combustion.

Cross-check

The selected set must include the carbonaceous particulate, the sulfate-bearing particulate, and the mineral ash, while excluding secondary nitrate and ammonia.

Therefore, the applicable statements are (A), (B), and (D) only.