Environment & Economic Benefits of Washed Coal

Electricity plays an extremely important role in sustaining economic growth, social development, and the welfare of a nation. Coal-based electricity is a dominant source of electricity generation in India and is expected to remain the primary source of electricity in the short to medium term, i.e., for about 15 years. The use of coal raises environmental concerns at the same time. The impacts of increased coal utilisation will have increased environmental impacts from emissions of air pollutants during coal mining, coal transportation, and coal combustion, contamination of the surface and groundwater, forest loss due to mining, etc.

A review of various studies brings out that coal washing leads to higher-quality fuel with a better heat value (which could increase thermal emissions by as much as 4%–5% on existing pulverised coal-fired boilers with an accompanying reduction in CO2 emissions), reduces fuel quantity requirements (handled and transported) and cost of transportation for the same energy value, enhances utilisation of installed generation capacity, reduces capital expenditure in the power plant, reduces ash volume in both pre-combustion and post-combustion stages, and also reduces the land requirement for ash disposal. Thus, coal beneficiation is one of the ways to improve the heat value of coal used in power plants

The use of washed coal has the potential to reduce CO2 emissions arising from power plants. The study conducted at the NTPC’s Dadri Power Plant, which used washed coal with around 31-32% ash, revealed that more than 600,000 tonnes per year of CO2 emissions can be reduced from coal combustion. Thus, it can be stated that the use of washed coal in thermal power plants can have significant environmental benefits, like a reduction in carbon emissions per unit of energy generation through improved thermal efficiency. With the use of washed coal, which can be combusted efficiently with less air,
the formation of NOx could also be reduced. Further, the use of low-ash coal could also result in reduced particulates in the flue gas, leading to a reduced load on the electrostatic precipitator (ESP) and possibly enhancing the life of ESPs.