MINERAL NITROGEN FERTILIZERS: ENVIRONMENTAL IMPACT OF PRODUCTION AND USE - Fertilizers: Components, Uses in Agriculture and Environmental Impacts - page 11

Table 5. The energy input for production of ammonia

Region GJ/ton NH 3 Reference

sources min max

World average 36.9 27.6 53.0 a

36.6 27.0 58.2 b

41.5 28.0 c

Europe 34.7 d

32.1 28.4 e

35.0 28.0 c

Russia + Central Europe 40.7 c

North America 37.9 28.0 c

China and India 47.6 c

Rest of the world 36.4
References: a = Williams & Al-Ansari, 2007; b = IFA, 2009; c = IEA, 2007; d = Haas & van Dijk, 2010
and e = Kongshaug, 1998.

Thus, due to consumption of natural gas or other hydrocarbons both for feedstock and for
fuel, CO 2 emissions are the major component of GHG budgets for ammonia manufacture.
Table 6. The GHGs emissions, expressed as CO 2 equivalent, for production of ammonia

Region ton CO 2 eq./ton NH 3 Reference

Sources min max
World average 2.1 1.5 3.1 a
Europe 1.9 b
1.8 1.6 c
References: a = Williams & Al-Ansari, 2007 b = Haas & van Dijk, 2010; c = Kongshaug, 1998.

Nitric Acid

Nitric acid is used in the manufacture of ammonium nitrate, calcium nitrate and
potassium nitrate. For fertilizer purposes, the acid strength is in the range of 50-65%.
Ammonia is vaporized, mixed with air and burned over a platinum/rhodium alloy catalyst to
form nitrogen monoxide and water (eq. 1) according the following reactions (UNEP/UNIDO,
1998):

4NH 3 + 5O 2  4NO + 6H 2 O (1)

Simultaneously, some nitrogen and nitrous oxide are formed (eq. 2 and 3):

4NH 3 + 3O 2  2N 2 + 6H 2 O (2)

4NH 3 + 4O 2  2N 2 O + 6H 2 O (3)

The nitric oxide is oxidized to nitrogen dioxide, and the latter is absorbed in water to give
nitric acid (eq. 4 and 5):