Sodium bromide double-effect evaporator

1. Working Principle of Sodium Bromide Double-Effect Evaporator

The sodium bromide double-effect evaporator utilizes a double-effect evaporation process, with two evaporators connected in series to achieve a rapid and energy-efficient evaporation process. The first-effect evaporator uses an external heat source (such as steam) to heat the sodium bromide solution, generating steam; the second-effect evaporator uses the secondary steam generated in the first effect as a heat source to continue evaporating the solution. This process fully utilizes the thermal energy of the secondary steam, significantly improving energy efficiency.

2. Process Flow

First-Effect Evaporation: The pretreated raw material liquid first enters the first-effect evaporator, where it is heated by externally introduced live steam and partially evaporates.

Secondary Steam Utilization: The high-temperature secondary steam generated in the first-effect evaporator is introduced into the second-effect evaporator as its heat source.

Second-Effect Evaporation: The second effect operates under a higher vacuum (lower pressure), resulting in a lower boiling point. The secondary steam from the first effect heats the material in this effect, causing it to evaporate and concentrate again.

Crystallization and Separation: After double-effect concentration, the solution enters a subsequent crystallizer for cooling and crystal precipitation. Finally, the sodium bromide solid is separated from the mother liquor by a centrifuge.

3. Structural Components of a Sodium Bromide Double-Effect Evaporator

Evaporator: Includes a first-effect and a second-effect evaporator, typically made of corrosion-resistant materials such as stainless steel or titanium alloy.

Preheater: Used to heat the solution to the evaporation temperature, typically a shell-and-tube or plate heat exchanger.

Condenser: Condenses the vapor generated during evaporation into liquid water, typically a shell-and-tube or plate condenser.

Storage Tank: Used to store the raw solution and the concentrated solution, made of corrosion-resistant materials.

Pump: Used to transport the solution and condensate, made of corrosion-resistant materials.

4. Advantages of a Sodium Bromide Double-Effect Evaporator

Energy Saving and Fast Operation: The double-effect evaporation system fully utilizes secondary steam, significantly reducing energy consumption.

Environmental Protection: Reduces waste liquid volume and lowers treatment costs.

Automation: Enables automated control, improving operational efficiency and stability.

5. Operational Precautions

Equipment Maintenance: Clean the equipment regularly to prevent scaling and corrosion; check for leaks.

Safe Operation: Operators must wear protective equipment and avoid contact with corrosive substances; flammable gases may be generated during evaporation, requiring explosion-proof measures.

Environmental Requirements: Waste gas generated during evaporation must be treated before discharge, and condensate must be treated for reuse or discharge.

6. Technical Parameters

Taking a double-effect sodium bromide evaporator with an evaporation capacity of 4t/h as an example:

Heating Area: Typically 100-150m² for a single-effect evaporator, and 80-120m² for a double-effect evaporator.

Steam Pressure: 0.1-0.2MPa for a single-effect evaporator, and 0.05-0.1MPa for a double-effect evaporator.

Temperature: Single-effect evaporators are typically 90-100℃, and double-effect evaporators are 80-90℃.

The design and operation of sodium bromide double-effect evaporators need to be optimized according to specific material characteristics and process requirements to ensure rapid system operation and product quality.