MVR Forced Circulation Evaporator
MVR Forced Circulation Evaporator
MVR is the abbreviated form of the mechanical vapor recompression. This is a technology that recovers the energy of the secondary vapor it generates and therefore reduces the demand for external energy. As early as in 1960s, Germany and France have applied this technology successfully to chemical, pharmaceutical, paper-making, waste water treatment and desalination fields.
MVR Technical Principle:
When mechanical vapor is recompressed, the mechanically driven compressor will compress the secondary vapor generated by the evaporator to form a higher pressure. In this sense, the compressor acts as a heat pump to increase energy to the vapor. In another word, in this process, the low-temperature vapor is compressed by the compressor to improve its temperature and pressure and increase its enthalpy and then flow into the heat exchanger for heat exchange and condensation so as to make use of the latent heat of the secondary vapor. Except machine startup, no generation of additional vapor is required during the entire evaporation process.
Principle MVR Forced Circulation Evaporator:
MVR forced circulation crystallization system comprises a vapor compressor,a heat exchanger, a crystallizer, and a forced circulation pump. The system makes use of the externally imposed power(circulating pump)to pump the solution and raw materials in the circulation pipe to the heating chamber. In doing so, the circulation rate is then greatly improved. After the circulating fluid passes through the heat exchanger for heating,it relieves pressure appropriately in the separator and becomes partially evaporated, cooling the liquid to the boiling temperature corresponding to the pressure. The secondary vapor separated from the separator and treated by the compressor is then handled to the heat exchanger for shell side heat exchange, maintaining the evaporating temperature of materials. When the system comes to the stable, no supplement of additional fresh steam is required.
Advantages of MVR Forced Circulation Evaporator:
1. Longer operating cycle:The boiling /evaporating process happens in the separator rather than on the heating surface so that the scaling phenomenon due to crusting and precipitation inside tubes is then minimized.
2. Optimized heat transfer surface:the flow rate inside tubes is determined by the circulating pump.
3. Suitable for easy -to-encrust and high viscosity liquids, acting as a concentrator in the multi-effect evaporation plant.
4. The forced circulation evaporator is operable as a crystallizing evaporator for salt solutions.
1. Low energy consumption, low operating costs.
2. Small space occupation.
3. Require fewer public utilities and less total investment.
4. Stable operation and high degree of automation.
5. Require no primary steam.
6. Short retention time due to frequently used single effect.
7. Simple process, high practicability and excellent service performance at some loads.
8. Low operation costs.
9. Capable of evaporating at and below 40 degree without refrigerating plant and particularly suitable for heat sensitive materials.
Design and Function:
Vapor compressor currently used for MVP technology has two forms:the positive displacement type and the centrifugal type
Among positive displacement compressors,the most commonly used compressor is the Roots compressor which compresses gas by bringing two or three lobed rotors to relative motions in the cylinder.This kind of compressor keeps two rotors engaged with each other by relying on synchromesh gears located on the rotor axle ends;the curved surface of each concave on the rotor,together with the inside wall of the cylinder,forms a working displacement,which carries away the gas from the gas suction port during rotor rotation,when the carried gas moves to the vicinity of the exhaust port,the pressure in the working displacement will abruptly pick up at the moment,It is to connect with the exhaust port due to the return of gas at higher pressure,and the gas then is delivered to the exhaust passage.This compressor has a large pressure ratio and a small sucking rate.
Centrifugal compressors provide gas energy by means of high-speed rotation of impeller blades.In these compressors,the gas is accelerated and then passes through the diffuser at downstream of the impller to decelerate.In doing so,the kinetic energy is transformed into pressure energy.According to the direction of fluids passing through the impller ,these compressors are named axial flow,mixed flow,or centrifugal compressors respecitively.They are renowed for large pressure ratio,big flow rate,and good stability.
Whichever is the most suitable compressor depends on specific operating conditions and the economy of the entire system.Critical parameter s include the pressure rise to be achieved and volume flow of steam to be compressed.
Corresponding parameter set not found, please add it in property template of background
MVR Stainless Steel 316L Crystallization Evaporator
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