The aim of sulphitation is to prevent either microbiological degradation or unwanted colour formation.
Field of application
Sulphitation is applied, for example, in sugar production and wine making.
Description of techniques, methods and equipment
Sulphitation is the introduction of sulphur dioxide (SO2) into liquids.
SO2 can be introduced in various forms:
- gaseous, generated either by burning of sulphur or from liquefied gas and direct expansion. The sulphur dioxide is drawn by a fan into an absorption column in which the liquid flows.
- liquid, from liquefied gas or in potassium bisulphite solution. The sulphur dioxide may also be stored as a liquid (under approximately 5 bar) in horizontal cylindrical tanks of 25 - 50 m3 capacity, from which it can then be introduced into the desired process stream.
- solid, as potassium metabisulphite dissolved in the liquid to be treated. The quantity of SO2 which can be added is regulated. An alternative, but more expensive, sulphite source is ammonium bisulphite. Furthermore, sodium bisulphite can also be used