MVR Mechanical vapor compression for waste water concentration

Working principle
Compress secondary steam by using steam centrifugal compressor or other steam compression device to make sure its physical properties meet with the requirements for heating steam ; evaporation that uses it as heating steam only requires fresh steam supply when the machine is started. After entering normal operation, there is no need to supply new steam and no (or very little) secondary steam needs condensation. Therefore MVR evaporation substantially cuts down steam demand but consumes more power.

Characteristics
Energy saving: high thermal efficiency, energy saving, lower energy consumption, the energy consumption of
1t water evaporation is about 1/5 to 1/3 of conventional evaporator.
Environmental protection: completely get rid of dependence on steam boiler, the mechanical vapor recompression evaporator could be start-up by electricity.Without boiler, don't need to burn coal, a small amount of steam, a small amount of cooling water.
The operation cost is low: due to low energy consumption, the operating cost of the whole evaporator is only 1/3 to 1/2 of traditional evaporator.
Small area: the system has high dense mechanical structure, so the cover area is less than 50% of traditional evaporator.
Mild evaporation: low temperature evaporation, the heat transfer temperature difference is low, so the system is not easy to scale.
High degree of automation: high degree of automation, simple operation, easy to operate.

Mechanical Vapor Recompression (MVR) evaporator
Mechanical vapor Recompression reduces the energy used in the evaporation process by up to 90% compared with conventional systems.
It works by reusing the heat energy contained in the vapor.This energy would otherwise be wasted.In a typical falling film evaporation plant the feed liquid enters the top of a vertical chamber called a Calandria.The liquid is dispersed across a large number of vertical tubes as it flows downwards it tends to form a film on the inside of the tube.Between the top and the bottom sections of the Calandria there is a sealed are where the tubes pass through a jacket of high temperature vapor.This section acts as a heating exchanger. As the hot vapor condenses on the outside of the tubes,it releases latent heat which raises the temperature of the feed liquid in the tubes.By the time the feed liquid leaves the bottom of the tube,much of the water has been evaporated off leaving a concentrated viscous liquid.The water which has been evaporated off leaves the tube as vapor.In the bottom section of the Calandria,some of the concentrated liquid gathers and can be drawn off,the hot mixture passes into a cooler chamber called the Separator where more of the concentrated liquid falls to the bottom to be drawn off and the vapor rises to the top.This vapor now contains most of the energy that was initially fed into the system.
The turbo fan sucks the vapor from the Separator and re-compresses it,raising the pressure and so increasing the temperature to the point where the vapor can once again be used as a source of heat.The unit is extremely robust,gas tight turbo fan ideally suited to the pressure,temperatures and volumes of the MVC evaporation process.At its heart is an ultra high speed impeller with a tip velocity of over 1000 Km/h faster than the speed of a jet airliner.The rotor probably has the highest tip velocity of any welded impeller ever manufactured.The re-heated vapor can then be fed back into the Calandria to provide the heat energy required to evaporate more feed liquid as it passes down the tubes.The Mechanical Vapor Compression process is a high energy efficient and cost effective way of retaining and reusing the latent heat contained in the vapor.Energy that would otherwise be wasted.Once the process has been started and brought up th temperature the only energy input required is the electricity to drive the Turbo fan.
As energy costs increase, the use of Mechanical Vapor Recompression (MVR) evaporators has also increased. The energy savings possible by using MVR technology is significant. MVR evaporators are designed to operate with very low specific energy consumption while producing clean condensate to minimize fresh water consumption in the mill.

MVR Applications
MVR energy-saving, low-temperature evaporation technology replaces simple evaporators. MVR is widely used in many applications, including:
Zero Liquid Discharge for industrial wastewater treatment
Chemical industry for evaporation, crystallization, and purification
Salt brine concentration
RO brine concentration
Beverage industry (milk, juice, sugar, etc.) concentration
Food industry (MSG, soy, protein, sugar) concentration
Pharmaceutical industry (medicines, vitamins) concentration

Working principle drawing

Machining & Assembling Workshop






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