Question
Help with drying a brine solution to recover salts
I need to dry a brine solution stream to recover most of the salts but am unable to use a solar pond (due to time and environmental reasons). Does anyone in this group have a suggestion as to what kind of COTS technologies I can use? The brine will be 200,000 - 300,000 ppm (mostly NaCl) and will be provided at 80+ C and up to 150 gpm. Are there technologies that would also allow me to control the size of the crystals?
All Answers (1)
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At that input temperature and concentration, you won't get any crystallization. Assuming you don't want to add any nucleating chemicals to your solution, you'll need to evaporate off most of that water to about 400,000 - 600,000 ppm or higher and lower the solution temperature to get the crystals. At that flow rate, I suggest you use an aersol cystallization method, where your brine is sprayed onto vertically-hung condensing sheets. Your flow rate is very high, about 850 tons of water per day, which will produce about 200 tons of NaCl per day, an enormous operation, which would require square miles of condensing sheets. Your crystal size can be controlled through both your aerosol spray system and the mechanical agitation of your plastic sheets, you would modulate your spray and thus the nucleation of the airborne solution and the crystallization buildup on the sheets, you can also control the removal rate of the moisture-laden air which will control the crystallization temperature. A system of this size would be a custom-build, but it would use COtS components. Not a big deal, I've done it on a smaller scale.
