IN FWG an excessively high evaporating temperature (approx. 60°C) leads to an increased scale occurrence in the heater tubing. & an excessively low evaporating temperature (approx. 45°C) increase the salinity of the obtained distillate.If the fwg runs in a low temp sea water area the evaporating temp will be low and therefore salinity will be high.To counteract this we close the vacuum adjusting valve to increase the evaporating temp slightly.
What is the reason behind this??How the salinity is increasing for low evaporating temp??why we increase the evaporating temp slightly??
please help me to get the reason behind this.