ANTISCALANT DOSE RATE & CLEANING BALL INTERRUPTION DURING MSF PLANT OPERATION

SUMMARY MSF desalination plants occasionally experience interruption of antiscalant dosing or circulation of cleaning balls. The interruption may be either due to sudden system failure or the system is to be isolated for maintenance works. In such situations, specific operational procedures are normally adopted to counter the consequences of maloperation of antiscalant dosing or cleaning balls systems. The various corrective measures that are normally adopted by SWCC MSF plants to mitigate the consequences of malfunctions of the antiscalant dose or the on-line ball cleaning systems are reviewed and presented in this study. The aim of this work is to establish operating conditions and consequences when antiscalant dosing or ball circulation is interrupted. The established operating conditions are intended to be used as a guide to recommend appropriate lines of actions to be followed by SWCC MSF plants to counter the impact of interruption of antiscalant dosing or cleaning balls circulation. Two series of evaluation tests were carried out. In the first series, extensive pilot plant tests were conducted to obtain preliminary assessment on the impact of sudden or gradual interruption of antiscalant dosing and the consequences when operating without cleaning balls circulation. In the second series, an actual evaluation test was conducted in one of the MSF distillers of Al-Khobar Phase-II plant to explore the consequences when antiscalant dosing was suddenly interrupted and stopped completely.