Nitric acid production
Nitric
acid is a key ingredient in nitrogen based fertilizers. Nitric
acid production involves the oxidation of ammonia (NH3)
using a platinum catalyst. Nitrous oxide emissions arise from
this process during the catalytic oxidation and it is estimated
that around 5 grams of nitrous oxide are produced in this way
for every kilogram of nitric acid which is manufactured.
Much recent progress has been made in reducing nitrous
oxide emissions from this process by using more efficient ammonia
oxidation conditions, with lower reaction temperatures preventing
so much of the ammonia ending up as nitrous oxide emission.
Nylon production
Nylon
production is responsible for nitrous oxide emission through its
requirement for adipic acid production. Adipic acid is a fine
powder used in the manufacture of nylon fibers, as well as for
some plastics, clothing, carpets and tyres. Adipic acid is also
used in the production of dyes and insecticides.
Nitrous oxide arises from adipic acid production
during the oxidation of a ketone-alcohol mixture with nitric acid.
It is estimated that for each kilogram of adipic acid made, around
30 grams of nitrous oxide is also produced.
However, improvements in the removal of nitrous
oxide before emissions to the atmosphere, such as by thermal decomposition,
can cue potential emissions form this source by over 90 percent.
Fossil Fuel Power Plants
The
burning of fossil fuels in electricity generation plants can lead
to substantial amounts of nitrous oxide production. Coal fired
power stations tend to dominate emissions form this source due
to their lower combustion efficiency compared to other fossil
fuels.
Emissions arise from the reaction of nitric oxide
during combustion, though the high temperatures involved often
mean that a large proportion of the nitrous oxide produced in
this way is destroyed before it can escape to the atmosphere.
Nevertheless, increasing global energy demands have
led to increased emissions from this source in recent decades
and the widespread use of coal as power station fuel mean that
nitrous oxide emissions from this source should not be overlooked.
