Ammonia

Ammonia is an inorganic compound with the formula NH3, forming the fundamental intermediate of the entire nitrogen fertiliser chain. In its commercial form, it is a liquefied gas under pressure or at low temperature, colourless, with a pungent odour and highly soluble in water. It contains 82 % nitrogen^[1]. Its production relies almost exclusively on the Haber-Bosch process, which fixes atmospheric nitrogen in combination with hydrogen.

Manufacture and industrial processes

The most widespread route for producing ammonia is steam methane reforming, a technique that equips roughly 77 % of global capacity.^[2] Natural gas supplies both the hydrogen required and the energy for the reaction. Modern large-scale units commonly reach 1,800 t/d and beyond.^[2] The energy consumption of an efficient plant lies around 33 MMBtu of natural gas per tonne of ammonia produced, equivalent to 35 GJ/t^[3][4].^[5] Coal-based units — predominant in China — require 50 % to 100 % additional energy per unit of nitrogen manufactured.^[5] By way of illustration, at a natural gas price of 7 USD/MMBtu and a consumption of 36 MMBtu/t NH3, gas accounts for approximately 87 % of cash production costs^[1].^[6]

Integration of ammonia and urea units on a single site is common practice, since urea synthesis requires carbon dioxide, a by-product of ammonia manufacture.^[7] It takes 0.58 t of ammonia to obtain 1 t of urea^[8].^[9]

Agronomic and industrial uses

Eighty per cent of world ammonia serves as a nitrogen source for fertilisers, with the remainder going to various industrial applications: plastics, fibres, explosives, hydrazine, amines, amides, nitriles, and nitrogen-containing organic intermediates for dyes and pharmaceuticals.^[3] Among inorganic derivatives are nitric acid, urea and sodium cyanide.^[3] Ammonia also plays a role in flue-gas cleaning through selective catalytic reduction of nitrogen oxides.

On the agronomic side, liquid ammonia is applied directly to the soil in certain regions — a widespread practice in the United States — but the bulk is converted on site into finished fertilisers.^[7] Urea alone consumes 57 % of global ammonia output.^[7] Producers of DAP, MAP and certain NPK fertilisers import ammonia, as phosphate-rich regions often lack nitrogen capacity.^[7] India and Morocco illustrate this pattern, using imported ammonia for their phosphate operations.^[10]

Market and international trade

World ammonia production reached 186 Mt in 2023, with an average annual growth rate of 0.8 % over the 2013-2023 period.^[11] China remains the leading producer.^[11] Only 9 % of output enters international trade, amounting to 16.6 Mt in 2023, down 8 % from the previous year^[7].^[7]

Trade flows have undergone profound restructuring since the Russo-Ukrainian conflict.^[12] The port of Yuzhny, on the Black Sea, traditionally constituted the main trading hub and the most liquid spot market.^[13] Since 2022, these flows have shifted markedly towards the Middle East and the Caribbean/Gulf of Mexico region.^[12] Asia is now in structural surplus owing to new units in Saudi Arabia and Oman.^[12] Houthi attacks in the Red Sea have forced part of the traffic to circumnavigate Africa, adding to freight costs and sustaining price differentials between East and West.^[12]

In the merchant market, Yara states it holds more than 20 % of globally traded ammonia.^[7] Buyers of merchant ammonia fall into four categories: basic industry, phosphate producers, non-vertically integrated nitrate manufacturers, and farmers practising direct application.^[7]

Storage and safety

Liquid ammonia is stored in three modes: fully refrigerated tanks of 10,000 to 30,000 t (up to 50,000 t), pressurised spheres or bullets up to roughly 1,700 t, or semi-refrigerated vessels.^[4] Emissions under normal operating conditions are negligible; major leaks, very rare at tank facilities, occur most often during transport or transfer.^[4] Rigorous design, construction and operation considerably limit the risk of incident.^[4]