Dinitrogen monoxide (N2O, nitrous oxide) is also formed
at the ammonia oxidation stage, and this can be difficult to remove.
Careful control of conditions will reduce the amount formed, but
some will inevitably be produced.
Several methods for the removal are being piloted, and are likely
to be in use in the near future. This is important because dinitrogen
monoxide is a significant greenhouse gas.
Methods being tried include:
- Using an additional catalyst at the ammonia
oxidation stage to decompose dinitrogen monoxide
- Catalytic reduction of dinitrogen monoxide
in the tail gas using ammonia
It is expected that application of these methods
will achieve a reduction of N2O emission in the region
of 80 - 90%.