Falling film single-effect evaporator

1. Falling Film Single-Effect Evaporator Structure and Principle

The falling film single-effect evaporator is an evaporation device suitable for heat-sensitive materials. Its working principle is as follows:

1.1. Feeding and Distribution: The liquid is added from the top of the evaporator and evenly distributed to each heat exchange tube through a liquid distribution device.

1.2. Evaporation Process: The liquid forms a uniform liquid film on the inner wall of the heat exchange tubes and flows down the tube wall in a film-like manner. During the downward flow, it is heated and vaporized by the shell-side heating medium (such as steam). The generated steam and liquid phase enter the separation chamber of the evaporator together.

1.3. Separation and Condensation: In the separation chamber, vapor and liquid are separated. The steam enters the condenser for condensation (single-effect operation), while the liquid phase is discharged from the separation chamber.

1.4. Vacuum System: A vacuum pump maintains negative pressure in the system, lowering the boiling point of the solution, suitable for heat-sensitive materials.

2. Main Components of a Falling Film Single-Effect Evaporator

2.1 Heating Chamber: Typically, a shell-and-tube heat exchanger is used. Steam heats the solution inside the tubes by passing between the tubes.

2.2 Separation Chamber: Used to separate the vapor and concentrate generated during evaporation.

2.3 Condenser: Cools the secondary vapor into a liquid state.

2.4 Vacuum System: Maintains negative pressure in the system, lowering the boiling point of the solution.

3. Application Scenarios of Falling Film Single-Effect Evaporators

3.1 Food Industry: Used for concentrating heat-sensitive materials such as goat milk, cow milk, lactic acid, fruit juice, and glucose.

3.2 Pharmaceutical Industry: Used for concentrating antibiotics and plant extracts.

3.3 Chemical Industry: Used for organic solvent recovery and continuous production of chemical products.

3.4 Environmental Protection: Used for wastewater treatment, achieving wastewater reduction, resource recovery, and zero discharge.

4. Selection Considerations for Falling Film Single-Effect Evaporators

4.1 Material Characteristics:

Heat-sensitive materials: Choose a falling film evaporator because its low operating temperature is suitable for heat-sensitive materials.

High-viscosity materials: For example, in an external circulation evaporator, a forced circulation pump ensures a feed flow rate of 1.0-3.5 m/s, preventing high-viscosity solutions from stagnating in the heating tubes.

Foaming materials: Membrane evaporation technology is used to reduce foam generation.

4.2. Processing capacity and efficiency: 

Select equipment specifications based on daily processing capacity to ensure matching evaporation capacity.

4.3. Comprehensive economic evaluation: 

Although single-effect evaporators have lower initial investment, their operating costs are relatively high, making them suitable for small-scale production or high-value-added materials.

4.4. Manufacturer qualifications: 

Choose manufacturers with ISO certification and proven track records.