In the MVC process, the vapour compressor is the key component in providing the mass and energy transfer required for evaporation. Moreover, the MVC loop does not, contrarily to MEE’s and TVC’s need a heat sink, and is therefore the optimal solution where cooling water is at a premium.
The mechanical work required to drive the vapour compressor is provided either by an electric motor or a back pressure steam turbine.
Usually the feed stream is evenly distributed onto a heat transfer surface of the evaporator heat exchanger. Evaporation takes place when the feed stream is heated to boiling by a heat source on the distillate side of the heat exchanger. In the MVC cycle, the water vapour drawn off the feed stream is compressed in the vapour compressor to a pressure level where it can be condensed and reused as heating medium.
The vapour condenses on the distillate side of the heat exchanger and can be reused as such as process water, and after a conditional polishing used as boiler feed water. The concentrated solution will be further processed, when necessary, in a dryer or a crystallizer or disposed of.
For more information on our range of MVC products you can visit the ExVel(R) turbo fans page.