MVR salt separation equipment

Process Flow

1. Pretreatment:

Impurity Removal: Large suspended solids and silt in the wastewater are removed using equipment such as screens and sedimentation tanks.

Water Quality Adjustment: The water quality and quantity are balanced in the equalization tank, and the pH value is adjusted to create suitable conditions for subsequent treatment.

2. Evaporation and Concentration:

Preheating: The pretreated wastewater is sent to a preheater, where waste heat from the system is used to preheat the wastewater, increasing the temperature before it enters the evaporator.

Evaporation: The preheated wastewater enters the evaporator and is heated in the heating chamber by high-temperature steam from the steam compressor to achieve the conditions required for evaporation.

3. Crystallization and Separation:

Crystallization: In the evaporation chamber, the wastewater is heated to generate a large amount of steam. As the water evaporates, the salt concentration gradually increases. When saturation or supersaturation is reached, salts crystallize and precipitate.

Solid-Liquid Separation: The crystallized salt slurry undergoes solid-liquid separation using equipment such as centrifuges and filters to obtain solid salt and centrifugal mother liquor.

4. Mother Liquor Treatment:

Recycling: The mother liquor can be returned to the evaporation system for further concentration, or further processed using other technologies (such as membrane separation and biochemical treatment).

Application Scenarios:

• Chemical Industry: Treating wastewater containing inorganic salts such as sodium chloride and sodium sulfate, achieving salt recovery and reuse.

• Metallurgical Industry: Recovering heavy metal salts, such as calcium chloride and magnesium chloride, reducing resource waste.

• Environmental Protection: Treating high-salt wastewater such as landfill leachate and reverse osmosis concentrate, reducing wastewater discharge and environmental pollution.

• Resource Recovery: Extracting valuable salts from wastewater, such as industrial salt and potassium salts, improving resource utilization.

Advantages:

• Energy Saving and Fast: Utilizing mechanical vapor recompression technology, the secondary steam generated during evaporation is compressed and reused, significantly reducing energy consumption and operating costs.

• High Product Purity: Through precise control of the crystallization process and the addition of seed crystals, high-purity salt products can be obtained, such as sodium chloride with a purity of over 99.2%.

• High Adaptability: Suitable for treating high-salinity wastewater of various concentrations and properties, and can be customized and optimized according to different process requirements.

• Stable Operation: Equipped with a better automatic control system, it can achieve precise control and remote monitoring of the evaporation process, reducing labor intensity and improving production efficiency.

Challenges and Solutions

Scaling and Corrosion: High-salinity wastewater easily leads to scaling and corrosion of equipment. Solutions include using corrosion-resistant materials (such as titanium, Hastelloy), regular equipment cleaning, and adding scale inhibitors.

Energy Consumption: Although MVR technology has reduced energy consumption, it remains a concern for large-scale treatment. Solutions include further optimizing process parameters and adopting technologies such as multi-effect evaporation.

Product Purity: The complex composition of mixed salts may result in low purity of crystalline salts. Solutions include pretreatment using membrane separation technologies (such as nanofiltration and reverse osmosis) and optimization of the crystallization process.

Mother Liquor Treatment: The high salt concentration in the mother liquor makes treatment difficult. Solutions include using stepwise crystallization and membrane concentration technologies to reduce mother liquor discharge.