EFC Technology – Process
In a continuous EFC process a salt water stream is fed to a crystallizer operating at the eutectic temperature and concentration. In the figure below, a simplified representation of the continuous EFC process is given.
An aqueous stream containing dissolved salt(s) is fed to the EFC crystallizer. In this step ice and salt are crystallizing simultaneously at the eutectic temperature of this specific system. Separation of the produced ice and salt from the crystallizing solution (or mother liquor) is done by utilizing the density difference between the three phases present (i.e. ice, salt and mother liquor). After the gravitational separation, a filtration step is required in order to remove the mother liquor trapped between the ice crystals and the salt crystals. The liquid in the product slurries is removed by mechanical operations (e.g. belt filtration, centrifuges, etc.) up to the desired level of product dryness. The extracted liquid is recycled back to the EFC process.
In some cases a bleed stream is required to remove trace components from the system. However, the volume of this stream is minimal compared to the feed stream.