Ammonia production
Ammonia is one of the most highly produced inorganic chemicals. There are numerous large-scale ammonia production plants worldwide, producing a total of 131 million tonnes of nitrogen (equivalent to 159 million tonnes of ammonia) in 2010. China produced 32.1% of the worldwide production, followed by India with 8.9%, Russia with 7.9%, and the United States with 6.3%. 80% or more of the ammonia produced is used for fertilizing agricultural crops. Ammonia is also used for the production of plastics, fibers, explosives, nitric acid (via the Ostwald process) and intermediates for dyes and pharmaceuticals.
Before the start of World War I, most ammonia was obtained by the dry distillation of nitrogenous vegetable and animal products; by the reduction of nitrous acid and nitrites with hydrogen; and also by the decomposition of ammonium salts by alkaline hydroxides or by quicklime, the salt most generally used being the chloride (sal-ammoniac).
Today, most ammonia is produced on a large scale by the Haber process with capacities of up to 3,300 metric tons per day. In this process, N2 and H2 gases are allowed to react at pressures of 200 bar.
A typical modern ammonia-producing plant first converts natural gas (i.e., methane) or LPG (liquefied petroleum gases such as propane and butane) or petroleum naphtha into gaseous hydrogen. The method for producing hydrogen from hydrocarbons is referred to as "Steam Reforming". The hydrogen is then combined with nitrogen to produce ammonia via the Haber-Bosch process.
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