Short-term low as well as high temperature operation of an MSF plant using Belgard EVN as a scale control additive

During a 40-day low temperature trial, conducted in 1979 using 2.0 ppm of Belgard EVN, the GOR ranged between 10.9 and 9.9 as against the design value of 8.0, while the heater fouling factor (FF) rose gradually from 0.02 × 10^-3 to 0.07 × 10^-3 m² .°C/W. A polyphosphate trial, carried out in 1978 on the same MSF plant, showed the rate of fouling of heater tubes to be four times that during the Belgard EVN trial. During the polyphosphate operation, the heater FF had in the same period climbed from 0.18 × 10^-3 to 0.70 × 10^-3 m² °C/W.In 1980, the top brine temperature of the unit was progressively increased from 87.8 to 104.4°C, whilst increasing the Belgard EVN dosage from 2.5 to 6.0 ppm. The GOR increased from 8 to 9 up to a top brine temperature of 98.9°C and then declined to about 7.7. The heater FF increased gradually from 0.10 × 10^-3 to 0.19 × 10^-3 m² .°C/W.