Forced Circulation Single-Effect Evaporator

1. Structure and Principle of Forced Circulation Single-Effect Evaporator

A forced circulation single-effect evaporator is an evaporation device that utilizes external power for feed liquid circulation. Its working principle is as follows:

1.1. External Power Circulation: A circulation pump forces the feed liquid through the heating tubes in one direction at a speed of 15 m/s, and superheats it under pressure higher than the normal boiling pressure.

1.2. Flash Evaporation or Rapid Boiling: After the feed liquid enters the separator, the pressure in the liquid drops rapidly, causing some liquid to flash or rapidly boil.

1.3. Independent Control: Due to the maintained liquid circulation, the flow rate and liquid temperature in the tubes can be controlled independently of a pre-selected temperature difference to meet product requirements.

2. Main Components of Forced Circulation Single-Effect Evaporator

2.1 Heating Tubes: The feed liquid is heated evenly within the heating tubes, preventing the "dry wall" phenomenon.

2.2 Separator: Used to separate the vapor produced by evaporation from the concentrated liquid.

2.3 Circulation Pump: Provides power to circulate the feed liquid within the system.

3. Application Scenarios of Forced Circulation Single-Effect Evaporators

Forced circulation single-effect evaporators are widely used in the following fields:

3.1 Chemical Industry: For the concentration of inorganic salts such as ammonium sulfate and sodium chloride.

3.2 Food Industry: For the evaporation and concentration of high-viscosity liquids, such as syrups and honey.

3.3 Pharmaceutical Industry: For the concentration of antibiotics and plant extracts.

3.4 Environmental Protection: For the evaporation and desalination of high-salinity wastewater, reducing environmental pollution.

4. Selection Considerations for Forced Circulation Single-Effect Evaporators

4.1 Material Characteristics:

High-viscosity or easily scaling wastewater: A forced circulation evaporator should be selected to avoid dead zones in the flow.

Heat-sensitive materials: Although forced circulation evaporators are not the best choice, they can be used in some cases, but the operating temperature needs to be controlled.

4.2 Processing Capacity and Efficiency:

Small-scale processing (<10 tons/day): Single-effect evaporators have low cost but high energy consumption.

Medium to large-scale processing (≥10 tons/day): MVR evaporators offer significant energy-saving advantages, with operating costs reduced by 30%-50% compared to triple-effect evaporators.

4.3. Comprehensive Economic Assessment:

Investment Cost: Single-effect evaporators have lower initial investment.

Operating Cost: Single-effect evaporators have relatively higher energy consumption and higher long-term operating costs.

5. Advantages and Disadvantages of Forced Circulation Single-Effect Evaporators

5.1 Advantages of Forced Circulation Single-Effect Evaporators:

High concentration ratio: Suitable for high-concentration operations.

Uniform heating: Prevents "dry wall" phenomenon, suitable for high-viscosity liquids.

Strong adaptability: Especially suitable for high-viscosity liquids or liquids prone to scaling.

5.2 Disadvantages of Forced Circulation Single-Effect Evaporators:

High pump flow rate: Relatively high power consumption.

High equipment vibration: Requires the entire unit to be supported by a plant or steel structure frame, resulting in higher investment in the plant or steel structure support.

Forced circulation single-effect evaporators play an important role in the evaporation and concentration of difficult industrial wastewater and high-viscosity liquids due to their rapid, stable, and highly adaptable characteristics.