Effective screening of scaling inhibitors for cooling water systems - Development of an accelerated electrochemical method

Abstract

Precipitation and inhibition of calcium carbonate, the most common form of scale in a variety of industrial processes, has been the subject of intense research. Control of scaling by chemical methods is considered to be most effective and economical. The wide anomalies noticed between the actual scale deposition and the rate predicted by the models based on the results of static laboratory test warrant the importance of studying scaling tendency on solid surfaces, rather than in bulk solution. Electrochemical deposition of calcium carbonate enables an efficient method for accomplishing such a task. Calcium carbonate deposition was obtained using an electrolyte solution containing calcium chloride, sodium bicarbonate and EDTA under the influence of an applied potential. The quantity of calcium carbonate deposit formed electrochemically both in the presence and absence of scaling inhibitors was used to assess the potency of the scaling inhibitor in preventing calcium carbonate scaling on surfaces. Since the deposition of calcium carbonate is effected electrochemically, the developed electrochemical method is very effective in distinguishing the ability of different scaling inhibitors in a very short duration of time.