EVALUATION OF BELGARD-EV-2000 AS ANTISCALANT CONTROL ADDITIVE IN MSF PLANTS

Scale formation on heat transfer surfaces, which is one of the basic p roblems in the distillation of seawater, can be effectively controlled or minimized by the addition of chemical additives. The most popular additives polyphosphate and Belgard EVN have extensively been used as scale control additives in Multi Stage Flash (MSF) plants in Kuwait. I n 1988, a new product was introduced by Ciba-Geigy known as Belgard EV 2000. Belgard EV 2000 is an aqueous solution of an organic acid which acts either as threshold inhibitor or increases the adsorption of sca le so as to reduce adhesion to metal surface. Ciba-Geigy collaborated with MEW in conducting a trial which is designed to show whether Belga rd EV 2000 is a more cost-effective alternative than the currently use d products Belgard EVN and polyphosphate. The present paper speculates the evaluation of Belgard EV 2000 as antiscaling agent in MSF plants. This additive was tested by the Ministry of Electricity and Water (ME &W) on unit A4 of Doha East Power and Water Production Station. The du ration of the trial was from 18th April to 28th August, 1988, on a 130 -day trial using low brine temperature (90 degrees C), with a unit cap acity of 6.0 migd. This additive exhibited satisfactory performance du ring the test period and successfully controlled the deposition of alk aline scale. No significant changes were observed in heater fouling wh en the dose level of Belgard EV 2000 was reduced from 2.5 ppm and main tained at 1.5 ppm. The brine heater and heat gain sections were inspec ted at the end of the trial period and the condenser tubes were found to be clean, which confirmed the capability of Belgard EV 2000 in cont rolling alkaline scale formation, in spite of the fact that the evapor ator was not fitted with a sponge ball cleaning system.