Chemical cleaning of sugar mill evaporators

Cleaning of evaporators is a major cost in sugar manufacture. Knowing the composition of scale allows effective cleaning agents for their removal to be identified. The paper briefly describes the analytical methods used in the identification of scale, lists the main scale components and explains the factors which affect the scale type formed. The paper also discussed the frequently used cleaning chemicals and their inability to remove oxalate-containing scale. The chemistry behind the ability of ethylenediamine tetra acetic acid EDTA to solubilise this type of scale and the summary of the results for both laboratory and factory EDTA trials are presented.