Energy and Environment. E nvironmental consequences of combustion processes – Part I (Smog, Acid Rain, and ozone depletion). Dr. Hassan Arafat Department of Chem. Eng. An-Najah University. (these slides were adopted, with modification, from Ms. Paulina Bohdanowicz , KTH Institute, Sweden).
Environmental consequences of combustion processes – Part I(Smog, Acid Rain, and ozone depletion)
Dr. Hassan Arafat
Department of Chem. Eng.
(these slides were adopted, with modification, from Ms. Paulina Bohdanowicz , KTH Institute, Sweden)
Source: WCI 2005
In order to meet forecasted global electricity demand it is estimated that 2000 MW of additional capacity will have to be installed every week over the next 20 years
Source: WCI 2005
Source: Liss R., Saunders A., Power generation and the Environment, Oxford 1990; Turns S.R., An introduction to combustion, concepts and application, Singapore 2000
Coal characteristics: CV of 20 MJ/kg and a sulphur content of 1%.
Plant characteristic: efficiency 34%, electricity production 65% of the total electricity it is capable of producing (650 MW-years in one year)
Source: Siemiński M., Środowiskowe zagrożenia zdrowia, Warszawa 2001
9.6% - Denmark
18.3% - Finland
41.2% - Greece
69.9% - Italy
95.4% - Austria
36.2% of EU inhabitants are exposed to excessive levels of particulate matter (PM10) (2000)
36.2% - Denmark
56.0% - Sweden
95.6% - Netherlands
97.6% - Greece
100.0% - Italy
100.0% - PortugalUrban air quality
Occurs mainly in urban areas but not exclusively
Smoke + fog = smogSmog
dates back to the 14th century
the "Killer Smog" reported in 1952, claimed 4000 fatalities in London - by far the most devastating event of this type in recorded history.
Inefficient combustion of high-sulphur coal => high concentration of unburned carbon soot and other particulates, acidic sulfate aerosols (such as sulfuric acid, H2SO4) as well as elevated levels of sulphur dioxide.
SO2 and soot, => sulphuric acid, sulfate aerosols
Characteristic brownish haze - formed usually under conditions of high humidity and relatively low temperatures, characterised by reducing and acidic properties.
In case of humid atmospheres carbon particulates serve as condensation nuclei for water droplets resulting in formation of fog, highly irritant.
Classical smog can persist for days when atmospheric conditions allow.Sulphur smog / London smog
Batter Sea power station, London, UK
encountered in automobile rich cities – with specific climatic conditions
mid-1940s - repeated occurrence of heavy injury to vegetable crops in the Los Angeles area - traced to high concentrations of ozone that appeared to be created at low altitudesPhotochemical smog / LA smog
local wood /dung /kerosene burning,
forest fires – clearing
can travel half way round the globe in a week
solar radiation reduced by up to 15%
Hundreds of thousands of deaths annually (2mln in India alone)
Warming of the atmosphere
Climate changes (floods & draughts)
Other Brown Clouds: South America, Mediterranean
The regional and global impact of the haze will intensify over the next 30 yearsAsian Brown Cloud
First studies on rain chemistry were conducted in late 1800s, but modern investigations date back to 1960s.
Nowadays the chemistry of atmospheric precipitation is fairly well known.
The phenomenon of acid rain has been known and studied from 1950s.
1960 – lowered fish production in Scandinavian lakes
In 1972 it became an international public policy issue at the first United Nations Conference on the Environment held in Stockholm.
The transboundary effect of atmospheric pollution has been officially accepted, based on the fact that sulphur and nitrogen oxides are commonly emitted in one location while the acid deposition occurs in distant area.
In Sweden and Norway around 90% of the acid deposition comes from other countries, primarily UK, Germany, Poland and other Central Europe countries. Canada receives major acid contribution form the US.Acid Rain
Source: Van Loon G.W., Duffy S.J., 2000.
Source: Boyle et al. 2003
Source: Boyle et al. 2003
Natural surface waters - pH of 6-8, acidified waters pH 3 (conditions unbearable for many aquatic species, which eventually die, and lakes become lifeless)
Today some 14000 lakes in Sweden are affected by acidification. Similar situation is in Canada
Nitrogen can induce eutrophication, which results in depletion of oxygen in water, further affecting the aquatic flora and faunaImpacts of acid rain
Areas with highly siliceous bedrock (granite, gneisses, quartzite, and quartzstone - acidic) – most vulnerable (Scandinavia, Canada, United Kingdom and Alps).
Acid deposition - enhances leaching of important cations such as calcium, potassium, magnesium and sodium - unavailable to plants as nutrients (soil depletion)
Reduced fertility of soil
Some metals (i.e. aluminium, and mercury) leach from acidified soils into watersImpacts of acid rain
The returns, in the form of improved health and reduced corrosion to buildings would by that same year amount to euro 12.8 billion.
Plus there are benefits that do not carry a price tag…Mitigation
A record size of ozone hole was 10.5 million square miles on Sept 19, 1998
Red color would denote high ozone levels; blue denotes lowAntartic/Arctic ozone hole
Humans (a 10% drop in stratospheric ozone levels is likely to lead globally to
300000 more skin cancers,
1.6 million more eye damage – cataracts) per year
Reptiles (damage to eggs)
Plants (reduced photosynthesis, increased sensitivity to stress)
Damage to marine ecosystems (direct and indirect)Ozone layer depletion