The basic thermal separation processes provided by theVap are the Multi-Stage-Flash process (MSF) and the Multi-Effect-Distillation (MED), while the MED is the process for example used in Multi-Column-Stills. The driving forces for these processes are temperature- and corresponding pressure differences. The required heat- and cooling sources can be implemented in several different ways, depending on available media for heating and cooling. This especially includes the combination with Thermal-Vapor-Compression (TVC) and Mechanical-Vapor-(Re-)Compression (MVR/MVC).

The FVMSF is the implementation of the Multi-Stage-Flash process in a completely polymer-based apparatus. Due to the applied partial vacuum, evaporation and condensation happen at temperatures well below 100°C. The application of a thin polymer film as condensation and heat transfer surface ensures high thermal performance and excellent corrosion resistance.

In the MSF process, a concentrate stream is conducted through a series of stages of declining temperature and pressure. As the pressure in each stage is lower than the saturation pressure of the entering concentrate, a fraction of the concentrate evaporates in the moment it enters the stage (flash evaporation).

In countercurrent to the concentrate stream, a feed stream is conducted through the module. Within a stage, this feed stream is used as coolant to condense the vapor generated from the concentrate flash. The sum of the vapor streams condensed in the individual effects forms the overall distillate stream of the system.

Usually, the feed water stream leaving the module at the first stage is heated further and then returned to the module as concentrate inlet stream of the first stage. This way, a big part of the heat transferred from the concentrate flash to the feed is recovered. By operating a number of stages in series, high thermal efficiencies can be achieved.

With the Film-Vacuum-Multi-Effect-Distillation (FVMED) we provide a completely polymer-based implementation of the Multi-Effect-Distillation (MED), for example applied in multi-column distillation systems. theVap uses thin polymer films as heat transfer surfaces, ensuring high thermal performance and excellent corrosion resistance. The process is run in partial vacuum and therewith well below 100°C.

Each of the multiple effects of a MED is heated by a vapor stream. This stream is condensed and forms a portion of distillate. The condensation heat is used to evaporate a fraction of the feed stream passing from effect to effect. The newly generated vapor and the remaining feed is passed on to the next effect, where the process is repeated on a lower temperature and pressure level.

In general, the condensate streams of the individual effects sum up to the overall distillate stream and the liquid remaining of the feed stream after the last effect forms the concentrate stream. The repeated reuse of the evaporation energy in a series of effects results in high thermal efficiencies.

theVap modules can as well be used to build a variety of membrane contactors for two or more liquid or gas streams. In contrast to the thermal processes, the driving force for membrane contactors are differences of chemical potentials instead of temperature or pressure differences. Nevertheless, combinations with thermal processes are possible as well.