The MVR Evaporative Crystalliser Plant at the ArcelorMittal Newcastle Works is designed to treat the brine effluent from the reverse osmosis and demin plants. The turnkey project was completed in 2009 at a present day cost in excess of R100 million. The plant has an operating capacity of 75 m3/hr of treated brine.
Brine solutions are first pumped to a buffer tank for pH adjustment and thereafter pumped through a pre-heater to two parallel evaporation circuits each consisting of an evaporator vessel, shell and tube heat exchanger and main circulation pump. The water vapour leaving the vessels is recycled and used to heat the circulating brine following additional energy input from two, 1100 kW high pressure turbo recompression MVR fans. High quality vapour condensate is collected and transferred back to the client as process water.
A portion of circulated brine is continuously bled to a double effect crystalliser, where steam is the energy source and the process condensate recovered is returned to the client. Crystals formed in these circuits are recovered and concentrated in a Solids Separation Plant before disposal to a waste site.
The plant includes a dedicated control room complete with PLC and SCADA system and all necessary utilities and services.