- Coal is mined and transported to a coal-fired power plant.
- Coal is commonly pulverized prior to being injected into boilers where
it is combusted. - Coal is combusted in the boiler, a structure that is surrounded by tubes
containing water. - The water in the tubes surrounding the boiler is turned into steam and
often super-heated after this conversion. - The high temperature, high pressure steam flows through a series of
pipes that connect to a turbine. - The steam spins the turbine at very high speeds.
- The turbine is connected to the generator which then moves wires
around a magnet, creating current or electricity. - The steam is then condensed, cooled, and returned as water to the
boiler. - The flue gases are sent up the stack after pollution control devices
remove specific pollutants.
There are a number of pollution control devices that are used to clean the
flue gases in a coal-fired power plant: – Baghouse filters remove particulate
matter from the gases as the gases are passed through fabric filters. - Electrostatic precipitators may also be used to remove particulate
matter by charging and then attracting the particles to collectors. - Charcoal, or wet carbon, is introduced at high temperatures to remove
mercury. - Ammonia is sprayed into the flue gases to remove NOx gases.
- Lime scrubbers are used to spray a solution of calcium carbonate to
remove SOx gases.
(d) Maximum 2 points total: 2 points for adequately identifying AND connecting
the environmental benefit to this transition.
As an environmental scientist, you might have concerns about the amount of
coal being consumed by China so you have been hired by the nuclear lobby
to convince China to begin constructing nuclear reactors to provide their
electricity. Describe one environmental benefit that China could realize by
making this transition.
Nuclear energy has a range of potentially positive environmental outcomes.
Of primary importance is the fact that no carbon dioxide is produced after