Civil Engineering Reference
In-Depth Information
from oil by treatment with hydrogen. In the actual combustion process, the main
compounds can be precipitated by adding lime:
CaO + SO
2
= CaSO
4
(1)
The amount of nitric oxide emitted can be reduced a great deal by reducing the
combustion temperature to 1000°C. The emission will also be less if the amount
of oxygen within the process is reduced. Nitrogen oxides can also be removed
from the emissions by adding ammonia (NH
3
); the resulting products are nitro-
gen and water:
NH
3
+ NO
x
= N
2
+ H
2
O
(2)
Combustion over 1000°C greatly reduces the amount of polycyclical aromatic
hydrocarbons (PAHs), but at the same time increases the amounts of nitrogen
oxides. The PAH substances are otherwise difficult to remove. It is possible to
clean out the heavy metals from the smoke by using a highly efficient filter.
Reduction of pollution during building use
This use of local materials would reduce transport-related pollution.
Table 2.4:
Energy sources and pollution
Energy source
CO
2
CO
NO
x
SO
x
Heavy
Dust
PAH
Radio-
metals
activity
Solar power
Wind power
Hydro-power
Wave power
Wood burning (dry
and efficient)
(x)
1
x
x
(x)
2
Peat burning
(x)
1
x
x
(x)
2
Coal burning
x
x
x
x
x
x
x
Natural gas burning
x
x
x
x
Oil burning
x
x
x
x
x
x
x
Nuclear power
x
Notes:
(x)
1
: see p. 32
(x)
2
: small amount by effective combustion
