A new zero-liquid-discharge brine concentrator using a Cascaded Fluidised Bed Ice Slurry Generator

Abstract

A new ZLD process for the salinity range beyond 70,000 ppm has been developed to reduce the volume of brine. We use the fluidised bed heat exchanger to cool down the brine to nucleate ice crystals and separate freshwater from the concentrated brine. Particle and wall collision and pressure fronts induced by particle-particle collision prevent ice formation in the internal surface of the heat exchanger. The concept of transition temperature difference, which is the limit for ice scaling, is used for our process simulation. We use the growth tank and wash column as part of the new process to increase the crystal size and wash the ice crystals efficiently. The new process benefits from the self-cleaning effect, and there is an improvement in the fluidised bed heat transfer coefficient. The process can be scaled up to increase brine mass flow rate using a tube bundle or achieve high concentrations by adding more fluidised bed heat exchangers.