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Continuous crystallization of Na2SO4

Start Evaporation crystallization model with default parameters, Na2SO4 mass fraction in feed 10%, cooling water 11°C. The objective is to concentrate a Na2SO4 solution from 10% to 20%, and to crystallise it by cooling.

  • Open cooling water on condenser, and fill boiler up to overflow with the 10% solution
  • Set heat intensity at 20A and bring the solution to the boil
  • Increase the boiler mass fraction up to 20%, feeding slowly the boiler to keep the level near overflow
  • When the boiler mass fraction is ~20%, start continuous feed and set it to keep this mass fraction (you could for example set a feed of 10 kg.h-1, heat at 20A, which give a condensate flowrate of 5 kg.h-1)
  • Wait until crystallizer level reach 20%, then set cooling water to it and agitation at 180 rpm
  • Look at saturation curve with button E, and look at the begining of the crystallization (you can seed the crystallizer to help crystallization startup)
  • When crystallizer is saturated and/or its level is around 70%, draw off the liquid-solid mixture to the filter by setting the level controller in automatic mode with a setpoint of 70%
  • Wait for the process to be at steady state, and verify global and Na2SO4 mass balance, and calculate crystallization yield.