MVR - Mechanical Vapor Recompression Distillation

Mechanical Vapor Recompression (MVR) distillation is a thermal desalination process use to produce freshwater from saline water sources, such as seawater. It is an energy-efficient method that utilizes mechanical compression to recycle vapor and recover heat, reducing the overall energy consumption of the distillation process.

Process Mechanism

In the MVR distillation process, the saline water is evaporated by applying heat to convert it into vapor. The vapor is then compresse mechanically using a compressor, which increases its temperature and pressure. The high-pressure vapor is subsequently condense, releasing its heat to the incoming saline water, and producing freshwater. The compresse vapor is then recycle back into the system, reducing the need for additional external heat input.

Process Steps

Preheating: The saline water is preheat using waste heat or other heat sources to reduce the energy requirements of the evaporation process.
Evaporation: The preheat saline water enters an evaporation chamber where it is heating, causing a portion of the water to evaporate. The evaporation is typically achieved under reduce pressure to lower the boiling point of the water.
Mechanical Vapor Compression: The vapor generate from the evaporation process is compresse using a mechanical compressor. The compression raises the vapor’s temperature and pressure, increasing its thermal energy.
Condensation: The compressed vapor is then condense by cooling surfaces or heat exchangers. As it condenses, it transfers its heat to the incoming saline water, causing further evaporation and producing freshwater. The condense vapor becomes a high-pressure liquid.
Expansion: The high-pressure liquid is pass through an expansion valve or turbine, which lowers its pressure. This expansion leads to a drop in temperature and the vaporization of a portion of the liquid.
Recompression: The resulting vapor is then compress again by the mechanical compressor, completing the vapor recompression cycle. The compress vapor is recycle back into the evaporation chamber to provide the necessary heat for further evaporation.

Significance & Advantages

The MVR distillation process enables the efficient use of heat by recovering and reusing the thermal energy contained in the vapor. This mechanical compression and heat recovery system significantly reduces the overall energy consumption compared to conventional distillation processes.
MVR distillation is often use in smaller-scale desalination plants, where energy efficiency is a priority. It is particularly suitable for applications where waste heat or low-grade heat sources are available. The process is gaining popularity due to its lower energy requirements, operational flexibility, and potential for integration with renewable energy sources.