Chem Haber Process Further Reading

16.2 pump 2 Compressor 1 Gases mixed and scrubbed 3 Converter 4 Cooler Liquid ammonia pump 5 Storage tanks 200 atmospheres 450°C N2, H2, NH3 N2, H2 N2, H2 N2 H2 beds of catalyst pump 1 The reactants are nitrogen and hydrogen. The nitrogen is obtained from air, and the hydrogen by reacting natural gas (methane) with steam, or by cracking hydrocarbons. See the details on the right. The two gases are mixed, and scrubbed (cleaned) to remove impurities. 2 The gas mixture is compressed. More and more gas is pumped in, until the pressure reaches 200 atmospheres. 3 The compressed gas flows to the converter – a round tank with beds of hot iron at 450 °C. The iron catalyses the reversible reaction: N2 (g) /H11001 3H2 (g) 2NH3 (g) But only 15% of the mixture leaving the converter is ammonia. 4 The mixture is cooled until the ammonia condenses to a liquid. The nitrogen and hydrogen are recycled to the converter for another chance to react. Steps 3 and 4 are continually repeated. 5 The ammonia is run into tanks, and stored as a liquid under pressure. S Ammonia plants are often built close to oil refineries, to make use of the hydrogen from cracking. !Obtaining the reactants Nitrogen Air is nearly 80% nitrogen, and 20%/uni00A0oxygen. The oxygen is removed/uni00A0by burning hydrogen: 2H2 (g) /H11001 O2 (g) 2H2O (l) That leaves mainly nitrogen, and a small amount of other gases. Hydrogen z It is usually made by reacting natural gas (methane) with steam: CH4 (g) /H11001 2H2O (g) CO2 (g) /H11001 4H2 (g) z It can also be made by cracking hydrocarbons from petroleum. For example: C2H6 (g) C2H4 (g) /H11001 H2 (g) catalyst catalyst ethane ethene SOME NON-METAL S AND THEIR COMPOUND S 226 Making ammonia in industry It’s a key chemical Ammonia is a very important chemical, because it is needed to make fertilisers – and we depend on fertilisers to grow enough food. It is made from nitrogen and hydrogen. The reaction is reversible. The Haber process The process used to make ammonia is called the Haber process. 16.2 pump 2 Compressor 1 Gases mixed and scrubbed 3 Converter 4 Cooler Liquid ammonia pump 5 Storage tanks 200 atmospheres 450°C N2, H2, NH3 N2, H2 N2, H2 N2 H2 beds of catalyst pump 1 The reactants are nitrogen and hydrogen. The nitrogen is obtained from air, and the hydrogen by reacting natural gas (methane) with steam, or by cracking hydrocarbons. See the details on the right. The two gases are mixed, and scrubbed (cleaned) to remove impurities. 2 The gas mixture is compressed. More and more gas is pumped in, until the pressure reaches 200 atmospheres. 3 The compressed gas flows to the converter – a round tank with beds of hot iron at 450 °C. The iron catalyses the reversible reaction: N2 (g) /H11001 3H2 (g) 2NH3 (g) But only 15% of the mixture leaving the converter is ammonia. 4 The mixture is cooled until the ammonia condenses to a liquid. The nitrogen and hydrogen are recycled to the converter for anot