Composition, formation, removal and avoidance of scales in evaporators and heat exchangers of sugar factories

Abstract

The intention of this paper is to give an overview about scaling in sugar factories, with the focus set on beet sugar factories but also including aspects which are specific for cane sugar production. Based on the analyses of some thousand scale samples collected during the last 40 years from sugar factories all over the world typical scale compositions and their abundance depending on factors like region, operation conditions of the factory, effect and type of evaporator are shown. Long time trends in scale composition and their relation to changing conditions in the sugar production are extracted from these data, e.g. the influence of longer campaigns (up to 140 days) on the scale composition in beet sugar factories in Central Europe. Based on its composition and the conditions during factory operation the formation of a specific scale is explained. For each type of scale a method for the removal, proven by laboratory studies and experience gained in the factories, is presented and recommendations are given to reduce or avoid the formation of a specific scale.