Karteikarten
L3: Point Source Pollution Control
Karten in diesem Stapel (12)
- 1How can switching fuel-type be beneficial?-1956 Clean Air Act in the UK reduced domestic coal burning by encouraging conversion of heaters to gas, oil, smokeless coal and electricity
- phasing out of leaded gasoline has greatly reduced atmospheric lead pollution - 2Different methods for point source pollution control (and what pollutants they control)-Thermal oxidisers (e.g. control methane)
-Packed absorption bed scrubbers (e.g. control SO2 by adding limestone-DRAX, produces gypsum as by-product)
-Condensers (removal of acids)
-Activated carbon (removal of organic pollutants such as PAHs or dioxins) - 3What are thermal oxidisers? (Give an example of their use)Thermal oxidisers remove pollutants such as VOCs and CO through high temperature combustion.
(Public acceptance of thermal oxidisers is not very good)
-Control methane emissions from landfills (methane is a GHG, worse than CO2)
--> combustion of methane gives CO2 - 4What are 'packed absorption bed scrubbers'Packed absorption bed scrubbers transfer soluble air pollutants such as bases (NH3) or acids (SO2, HCl) into the scrubber liquid.
-The most typical scrubber liquid is clean
water. Chemical additive options include
limestone and lime (for acid removal). - 5What are Condensers? How do they work?-Condensers can remove water and thus clean hot corrosive gases
-Condensation of gases can be achieved by reducing the temp (typical) or increasing pressure to transform for instance gaseous CO2 into liquid CO2 for injection and storage underground. - 6How does activated carbon work?Activated carbon is porous and has a huge surface area which facilitates the adsorption of organic pollutants (i.e. dioxins) from the gas phase.
(Silica gel instead of activated carbon can dry gases by removing water for instance to prevent corrosion of pumps) - 7How do you remove particle emissions?-Cyclone
-Scrubber
-Filters
-Electrostatic precipitators - 8Cyclone> 5um
- Low cost
-relies on centrifugal force to separate
particles from the air stream
-works for larger particles - 9Scrubber-5-10 um
- In packed bed scrubbers, particles are caught by the liquid film on the bed
- in venturi scrubbers water is
injected into the accelerated air stream to form larger water-solid particles - 10Filters- 1-100 um
-Also called baghouse
-filter fabric effective at removing fine particles
-but needs to be cleaned,
-tolerant if airstream is hot or corrosive - 11Electrostatic precipitators-< 1 um
-Charges particles and removes them on collector plates with the opposite charge,
-high capital costs
- not easily adapted to changing airstream
conditions - 12Coal fired treatment plant diagram
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- Beschreibung
- MSc Air Polluion Karteikarten am L3: Point Source Pollution Control, erstellt von Phoebe Stockton am 30/12/2017.
- Erstellt von
- Phoebe Stockton
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