Quadruple-effect evaporation and concentration equipment

Working Principle 

A four-effect evaporator and concentration unit consists of four evaporators (called "effects"). Each effect utilizes the secondary steam generated in the previous effect as a heat source. The specific process is as follows:

1. First Effect: The raw material liquid enters the first effect evaporator and is heated to boiling by external steam (usually live steam), producing secondary steam and concentrate.

2. Second Effect: The secondary steam generated in the first effect enters the second effect, serving as a heat source to heat the raw material liquid in the second effect, again producing secondary steam and concentrate.

3. Third Effect: The secondary steam from the second effect enters the third effect, continuing to heat the raw material liquid.

4. Fourth Effect: The secondary steam from the third effect enters the fourth effect, completing the final heating process.

The evaporation temperature of each effect gradually decreases. By utilizing the latent heat of steam in multiple stages, energy efficiency is significantly improved.

Advantages 

Rapid Energy Saving: Through multi-stage evaporation and steam reuse, energy consumption is significantly reduced. Compared to a single-effect evaporator, a four-effect evaporator can significantly reduce steam consumption, generally saving 70%-80% of steam.

High Concentration Efficiency: Four evaporators operate in series, with materials gradually concentrated in each effect, achieving a high concentration ratio in a short time.

Good Product Quality: The relatively low temperature in each effect allows for concentration of heat-sensitive materials under gentle conditions, reducing problems such as deterioration and discoloration caused by high temperatures.

Stable and Reliable Operation: The system is equipped with a complete automated control system that can monitor and adjust parameters such as temperature, pressure, and liquid level in each effect in real time.

Disadvantages:

• High Initial Cost: The initial investment cost of a four-effect evaporator is relatively high.

• High Operating and Maintenance Costs: Due to the complex structure of the equipment, operating and maintenance costs are also relatively high.

• Application Scenarios: Four-effect evaporation and concentration equipment is widely used in the following fields:

• Chemical Industry: Treatment of high-salt wastewater and acid/alkali solutions.

• Pharmaceutical Industry: Concentration of pharmaceutical solutions and solvent recovery.

• Food Industry: Concentration of fruit juice and dairy products.

• Environmental Protection: Zero-discharge treatment of industrial wastewater.

Selection Recommendations:

• Evaporation Capacity: Evaporators with an evaporation capacity exceeding 100T are recommended to use three-effect or four-effect evaporators.

• Material Properties: Select the appropriate evaporator type based on the material's viscosity, density, corrosiveness, heat sensitivity, and scaling tendency.

• Cost Considerations: The initial construction cost and operating costs are comprehensively considered, and the final cost is determined based on the manufacturer's specific circumstances.

Four-effect evaporation and concentration equipment is widely used in industrial production due to its advantages such as rapid energy saving, high concentration efficiency, and good product quality, especially suitable for applications with high requirements for evaporation efficiency and product quality.