The aim of sulphitation is to prevent either microbiological degradation or unwanted colour formation.
sugar production and wine making.
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.