MVR Evaporation Crystallization Equipment

I. Overview of MVR Evaporation Crystallization Technology

MVR is an advanced energy-saving evaporation technology that recycles steam energy by mechanically compressing the secondary steam generated during evaporation, increasing its temperature and pressure, and then using it as a heat source. Compared to traditional multi-effect evaporators, MVR technology can save 60%-90% of energy and reduce operating costs by 30%-80%.

II. Core Working Principle The MVR evaporation crystallization equipment's workflow consists of four key stages

1. Initial Evaporation Stage: The raw material liquid, heated by a preheater, enters the evaporation crystallizer.

6.It boils at a low temperature in a vacuum environment (typically 50-90℃), generating secondary steam (low-grade steam, temperature approximately 50-100℃).

This stage requires only a small amount of external steam for system startup.

2. Steam Compression Upgrade: The secondary steam is drawn into a mechanical compressor (Roots or centrifugal).

After compression, the steam pressure and temperature increase significantly (e.g., from 0.05MPa to 0.3MPa, temperature from 85℃ to 130℃). The low-grade steam is transformed into high-grade steam, resulting in a significant increase in enthalpy.

3. Heat Recycling: The high-temperature steam after compression... Steam enters the heat exchanger as a heat source to heat the new feed liquid.

The steam condenses into distilled water (which can be reused or discharged).

The feed liquid, after being heated, generates secondary steam again, forming a closed-loop energy cycle.

4. Crystallization and Separation Stage

The concentrated solution reaches a supersaturated state, and crystals precipitate in the crystallizer.

The crystals are separated by a centrifuge or filtration device, and the mother liquor is returned to the system for further processing.

Ultimately, solid-liquid separation and resource recovery are achieved.

III. Main System Components

1.Steam Compressor: The core component, which compresses and heats the secondary steam. Common types include Roots compressors and centrifugal compressors.

2.Evaporator Crystallizer: The place where materials are concentrated and crystallized, often using a forced circulation design.

3.Heat Exchanger: Shell-and-tube or plate structure for efficient heat transfer.

4.Gas-Liquid Separator: Separating steam and concentrate to ensure steam purity

5.Forced circulation pump: Maintains high-speed material flow (1.5-3.5 m/s) to prevent scaling

6.Vacuum system: Maintains negative system pressure to reduce evaporation temperature

7.PLC control system: Real-time monitoring of parameters such as temperature, pressure, and liquid level for fully automatic operation

8.Crystallization separation equipment: Thickener and centrifuge for crystal separation and collection

IV. Core Technical Features

1. Extreme Energy Saving

Over 90% of the heat after normal operation comes from secondary steam circulation, almost entirely independent of external live steam

Power consumption for treating 1 ton of water is only 2050 kWh, saving 70%-80% more energy than traditional evaporators

Annual processing capacity of 10 1. Projects handling 10,000 tons of wastewater can save over one million yuan in costs.

2. Low-Temperature Operation Protection

Evaporation temperature controlled at 50-90℃, suitable for heat-sensitive materials (such as vitamins, antibiotics, and food additives).

Avoids the destruction of effective ingredients due to high temperatures, achieving a retention rate of over 95%.

3. Anti-Scale Design

Forced circulation keeps materials in a turbulent state, with a flow rate of 1.5-3.5 m/s. Reduces scale risk by 35 times, extending the cleaning cycle to 36 months. Suitable for high-salt, high-hardness, silicon-containing, or high-viscosity (up to 500 cP) materials.

4. High Automation

PLC+DCS control system enables unattended operation. IoT remote monitoring ensures... Failure rate less than 5%.

Intelligent diagnostic system can predict potential faults such as scaling and blockage.

5. Compact structure

No need for large boiler rooms and steam pipes, the footprint is only 1/3 to 1/2 of traditional multi-effect evaporators. Modular design allows for flexible expansion according to processing capacity.

V. Main application areas

1. Environmental protection and wastewater treatment

Zero Discharge of high-salinity wastewater (ZLD): Treats electroplating, chemical, and coal chemical wastewater, achieving a salt recovery rate ≥95% and a freshwater reuse rate >90%.

Leachate concentration: Reduces volume by 80% to 90%, lowering subsequent treatment costs.

Desulfurization wastewater treatment: Produces industrial salt with a purity >97.5%.

2. Chemical industry

Inorganic Salt crystallization (sodium chloride, sodium sulfate, potassium sulfate, etc.)

Organic solvent recovery and chemical concentration

Fertilizer production (e.g., potassium sulfate MVR evaporation crystallization system)

3. Food and Pharmaceutical

Food: Milk, juice, glucose concentration, preserving nutrients

Pharmaceutical: API (active pharmaceutical ingredient) crystallization, antibiotic concentration, preparation of water for injection

Low-temperature operation ensures that the active pharmaceutical ingredients are not affected.

4. Resource Recovery

Heavy metal recovery (nickel, cobalt, copper recovery rate >98%)

Lithium salt extraction (purity up to 99.8%, used in battery production)

Salt chemical industry (refined edible salt, industrial salt production)

VI. Comparison with traditional evaporation technology

VII. Technological Development Trends

1. Intelligent Upgrade: Self-developed MPD design software optimizes compressor energy consumption and crystallization control.

2. Modular Integration: Factory prefabrication and rapid on-site installation shorten construction cycles.

3. Fractional Crystallization Technology: Achieving fractional crystallization of various salts (e.g., separation of NaCl and Na₂SO₄) through a combination of nanofiltration, electrodialysis, and MVR.

4. Corrosion-Resistant Materials: Widespread application of titanium alloys, duplex steel, and Hastelloy, adapting to highly corrosive conditions.

VIII. Selection and Maintenance Recommendations

1.Selection Points

Choose compressor type based on material characteristics (viscosity, scaling tendency, heat sensitivity). Type

Processing Capacity Range: Customizable from 1t/h to over 1000t/h

Material Selection: 316L stainless steel suitable for general operating conditions, titanium suitable for chloride ion environments

2.Key Maintenance Points:

Regularly discharge enriched mother liquor to prevent boiling point elevation from affecting efficiency.

Configure a CIP (clean-in-place) system for regular citric acid cleaning.

Monitor compressor vibration and heat exchanger temperature difference to prevent malfunctions.

MVR evaporation crystallization equipment, with its comprehensive advantages of high efficiency, energy saving, environmental compliance, and resource recycling, has become the preferred technology in the modern industrial evaporation crystallization field, especially under the background of "dual carbon" targets, its application prospects are very broad.