Coal Fired Power Station
Below is an animation showing the main processes in generating electricity using coal as the fuel source. However, some further useful points are also worth mentioning.
Flue Gas Treatment
Coal contains sulphur and when burnt it produces sulphur dioxide. Although, some sources of coal are low in their sulphur content some have a relatively high content. Low sulphur coals are usually more expensive.
Sulphur dioxide is a greenhouse gas and also produces acid rain. In order to remove the sulphur dioxide from the flue gases produced, the power stations have flue gas desulphurisation plants. Removal of sulphur from the flue gas involves passing the gases through a scrubber. This is like a shower. The gases rise up the scrubber which showers water down on them. The sulphur dissolves in the water to give sulphurous/sulphuric acid, this way the sulphur is removed from the flue gas and the remaining gas passes up a chimney and into the atmosphere. The sulphurous/sulphuric acid produced flows out of the scrubber and is neutralised with limestone (calcium carbonate) to form calcium sulphate, water and carbon dioxide. The calcium sulphate produced is known as de-sulphanated gypsum and is sold to plasterboard/plaster manufacturers.
This is steam at high pressure and above 100°C.