DIVERSITY OF APPLICATIONS FOR THE MECHANICAL VAPOUR RECOMPRESSION TECHNOLOGY

Mechanical Vapour Recompression (MVR) technology is applied since decades in many mining industries but rarely in alumina refineries. This technology offers the possibility to electrify the Bayer Process and hence decarbonize the production of alumina. Constraints of the alumina refinery like scaling of the heat exchanger heat surface and related washing frequency are also part of the other industry sectors where MVR is applied on a regular basis like in the Sodium Chloride industry or the Sodium Carbonate and Bicarbonate industry. After an introduction on the major principles of the MVR technology we will explain in this article the different possible cases of application of this technology: a) as a pre-concentration b) retrofit of a multiple effect unit c) for falling film trains of evaporation d) for forced circulation trains of evaporation. We will study the process flowsheet, the performances as well as COP calculation, ways to cope with potential scaling in order to keep a satisfying availability of the unit, OPEX comparison of MVR evaporation units against steam driven evaporation systems will also be given.