Page 29 - Curriculum Visions Dynamic Book

 The Contact process.
catalyst: a substance that speeds up a chemical reaction but itself remains unaltered at the end of the reaction.
EQUATION: Stage 1: Reacting sulphur dioxide and oxygen to produce sulphur trioxide
Sulphur dioxide gas + oxygen ➪ sulphur trioxide
Sulphur dioxide (SO2) and oxygen (O2)
 Converter containing vanadium pentoxide catalyst achieves 63% conversion to sulphur trioxide.
Gases cooled
Gases cooled
SO3 fed to an absorber
Remaining SO3
Gases fed to an absorber
➡
Uses of sulphuric acid
Sulphuric acid is used to make superphosphate fertilisers. These are the main kind of fertilisers used by farmers to increase yields of plants. However, there are many other uses, such as the manufacture of paint, synthetic fibres such as rayon, a wide range of plastics, detergents, dyes, explosives and medicines.
2SO2(g)
Sulphur
+ O2(g) ➪ 2SO3(g) Oxygen
+
 Converter containing vanadium pentoxide catalyst achieves 84% conversion to sulphur trioxide.
 Converter containing vanadium pentoxide catalyst achieves 93% conversion to sulphur trioxide.
 Converter containing vanadium pentoxide catalyst achieves 99.5% conversion to sulphur trioxide.
Sulphur trioxide absorbed to create 99.5% sulphuric acid, which is then diluted to 98% acid.
EQUATION: Reacting water with dissolved sulphur trioxide to form sulphuric acid
Sulphur trioxide + water ➪ concentrated sulphuric acid SO3(g) (absorbed in H2SO4)+ H2O(l) ➪ H2SO4(l)
Hydrogen
+➡
Remaining sulphur trioxide absorbed to create 99.5% sulphuric acid, which is then diluted to 98% acid.
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