Main gaseous pollutants emitted from a coal based power plant

Burning coal in a power plant produces a number of pollutants. Some of these pollutants are specified to the type of fuel or is a part of the combustion process or related to the design & configuration of the plants.

 Carbon Dioxide: - CO2 was thought of as a product of combustion and not as a pollutant. Kyoto protocol, effect of Green House Gases & Global warming issues have changed the way we look at CO2. CO2 has turned as the major Green House Gas. A fossil Fuel Power is the major contributor of CO2. 1 MJ of heat input produces 0.1 Kg of CO2.

 Sulphur Dioxide (SO2) or (SOx): - This is the product of combustion & depends on the amount of sulphur in coal. Sulphur in coal ranges from 0.1% to 3.5% depending upon the type and rank of coal. Power plants are largest emitters of SO2. In the presence of other gases SO2 forms H2S & can precipitate down as acid rain leading to destruction of ecosystem.

 Nitrogen Oxide (NOx): - Nitrogen is fuel and in the air reacts with O2 at high temperature to form various oxides of nitrogen. Fossil fuel power plants are the 2nd largest emitter of NOx. This is a hazardous pollutant creating visual and respiratory problems. Also NOx combines with water to form acid rain, smog and ground ozone.

 Ashes: - Ashes are the residue after the combustion. A 500MW coal fired power plant burning coal with around 20% ash, collect ash to the time of 2MT in five years. Disposing bulk of it on a long term basis can raise major environment issues.

 Particulate Matters: - Power plants have elaborate arrangements to collect the ashes. A small quantity still goes out through the stacks and is categorized as Particulate Matter Emission. The PM2.5 is of great concern since these are responsible for acute respiratory illness in humans.