A Rising Film Evaporator (RFE) is a vertical heat exchanger designed to concentrate solutions by evaporating the solvent. It is particularly effective for low-viscosity liquids and is widely used in industries like food, pharmaceuticals, and chemicals.

How It Works

1. Liquid Feed Entry: The liquid enters the evaporator from the bottom of the tubes.
2. Heat Transfer: Steam or another heating medium heats the liquid as it flows upward inside the tubes.
3. Film Formation: The heat causes the liquid to boil, forming vapor. The vapor pushes the liquid upward, creating a thin film along the tube walls.
4. Co-Current Flow: The vapor and liquid flow together upward, enhancing turbulence and improving heat transfer efficiency.
5. Vapor-Liquid Separation: At the top, the vapor and remaining liquid are separated in a vapor-liquid separator.

Features of Rising Film Evaporators

1. Continuous Process: Operates continuously, making it ideal for large-scale applications.
2. High Heat Transfer Efficiency: The co-current flow and turbulence improve heat transfer rates.
3. Low Residence Time: The liquid spends minimal time in the heated tubes, reducing the risk of thermal degradation.
4. Scalability: Can be scaled for small or large production needs.
5.  Adaptability: Handles low-viscosity liquids and is suitable for heat-sensitive materials.

Unique Operating Conditions

• Vacuum Operation: Can operate under vacuum for low-temperature evaporation, protecting heat-sensitive substances.
• Multi-Effect Setup: Can be integrated into multi-effect systems for improved energy efficiency.

Common Challenges Addressed by RFEs

1. Thermal Sensitivity: The short residence time minimizes heat exposure, preserving product quality.
2. Foaming Liquids: Effectively handles foaming liquids by separating vapor and liquid efficiently.
3. Energy Efficiency: Reduces energy consumption through optimized heat transfer.

Applications

• Food and Beverage: Concentrating juices, dairy products, and sweeteners.
• Pharmaceuticals: Solvent recovery and concentration of active ingredients.
•  Chemical Industry: Evaporation of low-viscosity or heat-sensitive fluids.
• Effluent Treatment: Recovery of water and valuable components.

Key Benefits

• High Efficiency: Optimized heat transfer and reduced energy usage.
• Gentle Processing: Preserves the quality of heat-sensitive materials.
• Versatility: Suitable for a wide range of low-viscosity liquids.
• Compact Design: Saves space while maintaining high throughput.

Material of Construction

• Options: SS 304, SS 316, MS, or as per client requirements.

Rising Film Evaporators are highly efficient and versatile systems, making them a preferred choice for
industries requiring reliable and consistent evaporation processes.