Overview
Multiple effect distillation with thermal vapour compression (MED-TVC)
Reliable instrumentation for highly corrosive thermal processes
Multi-effect distillation (MED) is a thermal sea water desalination technology which is typically used within integrated water and power plants (IWPP) because of the existence of easily available process heat on the plant. The sea water is sprayed over steam heated pipes in a heat exchanger. The evaporated sea water is used to heat the next stage (2nd Effect) to evaporate the brine from the first stage. Again, the evaporated seawater will be used to heat the 3rd stage. The steam condensate will be used as boiler feedwater after further treatment. The main flow of brine becomes further concentrated and is rejected to the sea.
Good flow, vacuum and level control is pivotal for the safe and efficient operation of the MED vessels. The heated brine is highly corrosive and tends to cause scaling. KROHNE OPTIFLUX electromagnetic flowmeter versions are available that are suitable for these corrosive conditions. OPTISONIC 3400 UFMs ultrasonic flowmeters are ideally suited for the distillate flow. The OPTIBAR DP 7060 C differential pressure transmitters with diaphragm seals reliably and accurately measure the liquid levels in the different stages.