Technologies are now available to tackle the environmental challenges associated with the use of coal. CCUS and HELE reduce CO2 emissions, but technologies are also available to reduce the release of pollutants. Several technologies are often available to mitigate any given environmental impact and reduce emissions.
Reducing particulate emissions
Several technologies have been developed to control particulate emissions and are widely deployed worldwide including coal cleaning, electrostatic precipitators (ESP), fabric filters, wet scrubbers and hot gas filtration systems. As well as capturing particulates, these technologies can increase SO2 removal, capture particulates and reduce the release of pollutants. Technologies can reduce particulate emissions by over 99.5% and are widely applied in both developed and developing countries.
Preventing acid rain
Oxides of sulphur (SOx) and nitrogen (NOx) are emitted during the combustion of fossil fuels, which react with water vapour and other substances in the atmosphere, which can form acid rain.
Flue gas desulphurisation (FGD), has been developed to reduce SO2 emissions from coal use. Also known as “scrubbers”, these systems typically use a chemical sorbent, usually lime or limestone, to remove SO2 from the flue gas – removing up to 99% of SOx emissions.
Fluidised bed combustion (FBC) is an efficient method of electricity production, that helps to reduce both NOx and SOx emissions significantly.
New technologies are also reducing coal’s water footprint. As with other forms of thermal power generation, water in coal-fired plants is used in different ways depending on the type of cooling technology employed. Many technologies do not consume significant amounts of water, but it is important to make sure that the extraction and return process minimises impacts on water temperature and wildlife.
Coal Combustion Products
The combustion of coal generates waste consisting primarily of non-combustible mineral matter along with a small amount of unreacted carbon. The production of this waste can be minimised by coal cleaning prior to combustion.
Waste can be further minimised by adopting high efficiency coal combustion technologies. The material produced from coal combustion can also be repurposed and used as valuable materials in the construction and civil engineering industry – coal combustion products (CCPs), such as fly ash, can be used to produce concrete.