HaberBoschVerfahren

The Haber-Bosch process, also known in German as the Haber-Bosch-Verfahren, is an industrial method for synthesizing ammonia from nitrogen and hydrogen under high temperature and pressure in the presence of a catalyst. The core reaction is N2 + 3 H2 ⇌ 2 NH3, a reversible, exothermic process. To make the rate practical and the yield high, industrial implementations operate at high pressure and elevated temperatures, typically about 150–250 bar and 400–500°C. An iron-based catalyst with promoters such as alkali and aluminum oxides is used to increase activity and prolong life; the catalyst is arranged in multiple reactors with cooling and gas recycle steps to approach equilibrium continually.

Feed gases are produced from nitrogen in the air and hydrogen usually from steam reforming of natural gas, with purification before entering the reactor. The ammonia formed is removed by cooling and compression, while unreacted gases are recycled to improve overall efficiency. The process is energy-intensive due to gas compression and heating, but the high yields enabled by the equilibrium shift and catalysts make it practical for large-scale fertilizer production.

Historically, the process was developed by Fritz Haber and industrialized by Carl Bosch in the early 20th century, enabling the large-scale synthesis of ammonia for agricultural fertilizers and, in wartime, explosives. Its development profoundly affected agriculture, food production, and geopolitics. In modern times, efforts focus on reducing energy use, adopting green hydrogen, and improving catalysts and process integration.