Q. Design an Evaporator System?

The Evaporator System is designed to produce high quality distillate. The feed water to the evaporator system is dosed with antiscalant and received in the evaporator feed header. The feed water is then sent through the plate and frame heat exchangers for preheating. The incoming feed water receives heat from the distillate leaving the evaporators. The preheated feed water is pumped to the evaporator.

Vapour generated in the evaporator flows to high-efficiency external mist eliminator, then to the vapour compressor and then is sent to the evaporator shell for heat transfer and condensation. The vapour that condenses is high purity distillate water, which flows to Distillate Tank and is pumped out of the evaporator system.

The brine from the evaporator sump is pumped with a recirculation pump to the top head of the evaporator column where it is distributed onto the tube walls. The brine flows down the inside of the tube and evaporates as it received energy from the steam condensing on the outside wall. The highly concentrated brine that is not evaporated is blown down from the evaporator system to the brine waste disposal system.

Vapour compression uses mechanical energy input to achieve evaporation and condensation. The water vapour is compressed, increasing its saturation pressure so that when it condenses, it does so at a higher temperature. The compressed vapour flows to the heating side of the evaporator. As it condenses, it transfers the latent heat of vaporization back to the liquid film on the tube side.