A Review of 4 Common Types of MVR Evaporators: Features and Application Scenarios

MVR evaporators have evolved into various structural forms based on material characteristics and process requirements. The following are four common types of MVR evaporators, outlining their structural features, operational advantages, and typical application scenarios to facilitate engineering selection and practical application reference.

I. Falling Film MVR Evaporator

Features: Material enters from the top of the evaporator, is evenly distributed on the inner wall of the heat exchange tubes, forming a liquid film that flows downwards, exchanging heat with the heat source for evaporation.

High heat transfer coefficient, low temperature difference loss, low evaporation temperature, and short residence time.

Suitable for heat-sensitive and easily foaming materials; less prone to coking.

Advantages: Low energy consumption, high evaporation intensity.

Gentle evaporation, minimal loss of effective components.

Applications: Pharmaceutical industry: Concentration of fermentation broth and traditional Chinese medicine extracts.

Food industry: Concentration of fruit juice, dairy products, and protein solutions.

Chemical industry: Evaporation of low-viscosity solutions and solvent recovery.

Limitations: Not suitable for high-viscosity, high-concentration, and easily scaling materials.

II. Forced Circulation MVR Evaporator

Features: Material is forced to circulate at high speed within the heating tubes by a high-flow-rate circulation pump; boiling evaporation is completed within the separator.

Rugged structure, resistant to high concentrations and scaling; can handle materials with high boiling point rise.

Advantages: Prevents scaling and clogging; adaptable to high-salt, high-solids-content solutions.

Stable operation, easy to implement continuous operation.

Applications: High-salt wastewater treatment, concentration and crystallization of saline mother liquor.

Evaporation of high-concentration intermediates in fine chemical and pharmaceutical industries.

Seawater desalination, resource recovery (e.g., sodium chloride, sodium sulfate crystallization).

Limitations: Higher power consumption than falling film evaporators.

Larger equipment investment.

III. Rising Film MVR Evaporator

Features: Material enters the heat exchange tube from the bottom, boils rapidly after heating, and the steam drives the liquid film upwards for evaporation.

High evaporation intensity and high heat transfer efficiency.

Advantages: Fast evaporation rate, short material heating time.

Simple structure, high operational flexibility.

Applications: Concentration of heat-sensitive materials (e.g., some pharmaceutical solutions, food liquids).

Rapid evaporation of low-viscosity, non-scaling solutions.

Pre-concentration stage of industrial wastewater.

Limitations: Sensitive to material flowability and scaling tendency. Not suitable for high-viscosity or high-concentration materials.

IV. OSLO/DTB Crystallizing MVR Evaporator (with Crystallizer)

Features: Combines evaporation and crystallization processes, featuring a unique crystal growth zone, enabling large-particle crystallization with controllable particle size.

DTB (drainage tube with baffles) or OSLO (external circulation) structure facilitates separation of clear liquid and crystals.

Suitable for continuous crystallization, graded crystallization, and high-quality crystal production.

Advantages: Large and uniform crystal particle size distribution, facilitating subsequent centrifugal separation and drying.

Controllable supersaturation, providing a good crystal growth environment.

Application Scenarios: Crystallization and purification of valuable substances in the pharmaceutical industry (e.g., antibiotics, organic acids).

High-quality crystallization separation of fine chemical products (e.g., amino acids, vitamins).

Resource recovery from high-salt wastewater, producing industrial salt through salt separation and crystallization.

Limitations: Complex structure, high investment and automation requirements.

Requires precise process control and operational experience. 

Comparison Summary Table

Selection Recommendations

• Material characteristics are the primary basis for selection, such as thermosensitivity, viscosity, scaling tendency, concentration, etc.

• Process objectives (concentration, crystallization, solvent recovery, zero wastewater discharge) determine the structural type.

• Operating economy and automation level also need to be considered comprehensively.

Conclusion

Different types of MVR evaporators have different focuses for different processes and material requirements. In practical applications, it is necessary to combine water quality, output, product quality, investment and operating costs to select the most suitable type of equipment. If necessary, they can be combined to achieve the comprehensive goals of high efficiency, energy saving, resource recycling and green environmental protection.