25 years experience in the development and application of scale inhibitors

Abstract

This paper traces the development, of desalination scale inhibitors from the early polyphosphate based formulations through to the latest high temperature additives. Advances in desalination plant technology are outlined with special reference to the changing demands made on the additives. A comparison of acid and additive treatment methods is made and the various basic mechanisms of scale formation are briefly covered, together with the principal plant design factors affecting inhibitor efficiency. The long term suitability of an additive is examined with reference to the ease of plant cleaning and the maintenance of demister efficiency as well as the more obvious parameters such as the maintenance of clean heat transfer surfaces throughout the plant. A test rig permitting the laboratory evaluation of inhibitor formulations under simulated plant conditions is described. The paper concludes with an attempt to predict future trends in plant design and the type of inhibitor required for successful long term plant operation.