Flashcards
David Werner Exercises
Cards in this deck (18)
- 1N combustion produces:NO
NO2
--> NOx makes up 30%of N-content, at high flame peak temperatures, most of N combusted converts to NOx - 2Where does Fe end up?Fe and heavy metals end up in ash and fly ash
- 3Where do Hg, Pb, Cd end up?Volatalise easily and appear in flue gas as vapours/fumes of their oxides
- 4Adding limestone to sulphur: reaction:CaCO3 + SO2 --> CaSO3 + CO2
(limestone + sulphur dioxide --> calcium sulphite + CO2) - 5Calcium sulphite reaction:CaSO3 + H2O +1/2 O2--> CaSO4 + H2O
(calcium sulphite oxidised to calcium sulphate (GYPSUM) - 6What else happens to sulphur dioxide ?Can be oxidised to sulphur trioxide (SO3) which dissolves in condensate water during cooling to produce sulphuric acid, (H2SO4) which can be sold to the chemical industry
- 7How can you control NOx emissions?Optimise fuel-burning conditions: low NOx burner; or through non-catalytic and catalytic reduction of NOx with urea or ammonia (NH3)
NOx + NH3 --> N2 +H2O
(not balanced as NOx not defined)
-Because less than 100% of N in fuel is converted to NOx, NH3 consumption is difficult to predict - 8How can you control particulate emissions?-filter bags
-electrostatic precipitation
--> filter ash is alkaline and contains toxic metals at ppm concs.
--> filter ash used in building industry (concrete) - 9Heavy metal content in ash?Because c. 20% of the coal content is not burnable (ash content): heavy metals are concentrated by a factor of 5 relative to conc. in coal
- 10Role of fuel management in reducing air pollution from domestic heating?-Ldn smog event
-Domestic heating fuel was switched from coal to smokeless coal..later to oil, gas and electricity
-Reduced air pollution from domestic heating - 11Role of fuel management in reducing air pollution from road traffic?-Replacement of lead with unleaded petrol
-Petrol engines produce less soot than diesel - some govt.s tax diesel more
-electric vehicles can reduce air poll. BUT dep. on where electricity from
-H-fuelled cars - 12Role of fuel management in reducing air pollution from waste incinerators?-recycling of batteries to prevent Mercury, Pb and Cd emissions
-Recycling of PVC to prevent formation of dioxins and HCl from combustion of PVC - 13Role of fuel management in reducing air pollution from power stations?Coal --> nat. gas (cleaner fuel)
- 14Standards for sulphur dioxide:125 ug/m3 24 hour mean
NOT to be exceeded > 24 times/y - 15CAP and TRADEEU Emission Trading Scheme (EU ETS) caps the CO2 emissions
from large installations and allowances are traded amongst emitters - 16Another way of encouraging CO2 reduction in emissions?A carbon tax is a price incentive to reduce CO2 emissions
-An industry concern is that a carbon tax transfers revenues from the
private sector to the government - 17What is the efficiency of FGD?90%
- 18How many kwH in a GwH?1,000,000
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- MSc Air Polluion Flashcards on David Werner Exercises, created by Phoebe Stockton on 16/01/2018.
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- Phoebe Stockton
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