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Fritz Haber, 1918. The Haber process, [1] also called the Haber–Bosch process, is the main industrial procedure for the production of ammonia. [2] [3] It converts atmospheric nitrogen (N 2) to ammonia (NH 3) by a reaction with hydrogen (H 2) using finely divided iron metal as a catalyst:
The United States produces 9–10 million tons of hydrogen per year, mostly with steam reforming of natural gas. [13] The worldwide ammonia production, using hydrogen derived from steam reforming, was 144 million tonnes in 2018. [14] The energy consumption has been reduced from 100 GJ/tonne of ammonia in 1920 to 27 GJ by 2019. [15]
The liquid nitrogen wash has two principle functions: [1] Removal of impurities such as carbon monoxide, argon and methane from the crude hydrogen gas; Addition of the required stoichiometric amount of nitrogen to the hydrogen stream to achieve the correct ammonia synthesis gas ratio of hydrogen to nitrogen of 3 : 1
The following table lists the Van der Waals constants (from the Van der Waals equation) for a number of common gases and volatile liquids. [ 1 ] To convert from L 2 b a r / m o l 2 {\displaystyle \mathrm {L^{2}bar/mol^{2}} } to L 2 k P a / m o l 2 {\displaystyle \mathrm {L^{2}kPa/mol^{2}} } , multiply by 100.
The Haber process produces ammonia (NH 3) from molecular nitrogen (N 2) and hydrogen (H 2), the latter usually but not necessarily produced by steam reforming methane (CH 4) gas in current practice. The ammonia from the Haber process is then converted into nitric acid (HNO 3 ) in the Ostwald process .
Forming gas is a mixture of hydrogen (mole fraction varies) [1] and nitrogen. It is sometimes called a "dissociated ammonia atmosphere" due to the reaction which generates it: 2 NH 3 → 3 H 2 + N 2. It can also be manufactured by thermal cracking of ammonia, in an ammonia cracker or forming gas generator. [2]
In general, the SCR unit is located between the furnace economizer and the air heater, and the ammonia is injected into the catalyst chamber through an ammonia injection grid. As in other SCR applications, the temperature of operation is critical. Ammonia slip (unreacted ammonia) is also an issue with SCR technology used in power plants.
Water gas has a lower heat of combustion than coal gas, so the calorific value was often boosted by passing the gas through a heated retort, into which oil was sprayed. The resulting mixed gas was called carburetted water gas. The average composition of carburetted water gas is as follows: H 2 =34-38%; CO=23-28%; saturated hydrocarbon=17-21% ...