Description

Project Overview

This project features a single-effect falling film evaporator system developed for the concentration of molasses solution, designed to increase the solids concentration from approximately 15% to 70% while maintaining the material temperature below 60°C throughout the entire evaporation process.

Molasses is a heat-sensitive material containing sugars and other organic components. Excessive temperature or prolonged heating may lead to caramelization, color deterioration, product degradation, and fouling of the heat-transfer surfaces. Therefore, achieving a high final concentration while strictly limiting the evaporation temperature was one of the key technical requirements of this project.

Our Solution: Vacuum Falling Film Evaporation

To meet the low-temperature requirement, a single-effect falling film evaporator operating under vacuum was selected.

Under vacuum conditions, the boiling point of water is significantly reduced, allowing moisture to be removed from the molasses solution at temperatures well below the normal atmospheric boiling point.

The falling film evaporator further minimizes thermal exposure. The feed solution is uniformly distributed at the top of the vertical heating tubes and flows downward along the tube walls as a thin liquid film. Evaporation takes place continuously during the downward flow, providing efficient heat transfer with a relatively short material residence time.

This combination of vacuum evaporation, falling-film heat transfer, and precise temperature control enables the required concentration to be achieved while minimizing the risk of thermal degradation. 

Designed for Heat-Sensitive and High-Viscosity Material

One of the major advantages of falling film evaporation is its short residence time, making it particularly suitable for temperature-sensitive products.

For molasses concentration, special consideration is given to:

•  Low-temperature evaporation under vacuum

•  Material temperature maintained below 60°C

•  Uniform liquid distribution across the heating tubes

•  Sufficient tube wetting at high concentration

•  Short material residence time

•  Controlled heating steam temperature and pressure

•  Efficient vapor-liquid separation

•  Prevention of localized overheating and caramelization

•  Consideration of viscosity increase at high solids concentration 

•  Easy CIP operation

As the molasses concentration increases, its viscosity rises significantly while the liquid flow rate decreases. Where necessary, a recirculation arrangement can also be incorporated to maintain sufficient liquid flow and uniform tube wetting as the product approaches its final concentration.

Process Configuration

The typical process configuration is:

Feed Solution → Preheating → Falling Film Heater → Vapor-Liquid Separation → 70% Concentrated Molasses

The secondary vapor generated during evaporation is condensed and collected:   

Secondary Vapor → Condenser → Condensate Collection

A vacuum system maintains the required low operating pressure and continuously removes non-condensable gases, enabling stable evaporation at the required low temperature. 

Key Benefits

The single-effect falling film evaporator provides several advantages for molasses and other heat-sensitive liquid concentration applications:

falling film evaporator

•  Low evaporation temperature

•  Short residence time

•  Reduced risk of thermal degradation

•  High concentration capability

•  Compact equipment arrangement

•  Simple process configuration

•  Stable automatic operation

•  Easy cleaning and maintenance

•  Suitable for heat-sensitive sugar solutions and similar products

Customized Evaporation Solutions

The performance of a molasses evaporator depends strongly on the actual material properties, particularly viscosity, boiling-point elevation, solids composition, foaming tendency, and fouling characteristics.

For each project, the evaporation system is therefore engineered according to the actual feed characteristics, required final concentration, available utilities, and product-quality requirements.

With appropriate vacuum control, heat-transfer design, liquid distribution, and process control, falling film evaporation provides an efficient solution for concentrating molasses and other heat-sensitive solutions to high solids concentrations while maintaining strict low-temperature operating conditions.

single effect falling film evaporator

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