Description

Overview

High Fructose Corn Syrup (HFCS) is a widely used sweetener, mainly produced from corn starch through enzymatic hydrolysis and saccharification. It is extensively applied in various food and beverage products, especially in carbonated drinks, desserts, condiments, and processed foods.

HFCS evaporation and concentration is a critical step in HFCS production, which removes excess water from dilute syrup under controlled thermal conditions. Due to the heat-sensitive nature of HFCS, a low heating temperature and short residence time evaporation system is required.

Five-effect Falling Film Evaporator

A five-effect falling film evaporator integrated with a TVR system was employed in this HFCS concentration project.

The HFCS from the previous process stage is first preheated through a condensate preheater and an exhaust vapor preheater, enabling effective recovery and utilization of latent heat from both condensate and secondary vapor. After preheating, the HFCS feed enters the evaporator system.

The feed is then uniformly distributed at the top of each heater via specially designed liquid distribution devices. A thin liquid film is formed on the inner tube surfaces and flows downward under gravity. Efficient heat transfer occurs through the tube walls, leading to rapid evaporation of water from the solution.

The generated vapor is utilized sequentially across the multiple effects to maximize thermal efficiency. Finally, the concentrated HFCS product, with a solids content of 70–77%, is discharged from the last effect.

Advantages of Five-Effect Falling Film Evaporator

HFCS exhibits several properties that strongly influence equipment design:

• High thermal sensitivity, leading to color formation at elevated temperatures

• Fouling tendency due to sugar degradation and trace impurities

• Rapid viscosity increase with rising concentration

• Relatively low foaming tendency compared to protein-based solutions

Based on the above properities, a five-effect falling film evaporator was selected.

Advantages of the selected system: 

• High Heat Transfer Efficiency

The falling film mechanism ensures uniform liquid distribution and thin film formation on the heating surface, resulting in high heat transfer coefficients.

• Short Residence Time

The liquid passes through the heating tubes within seconds, significantly reducing thermal degradation of HFCS.

• Energy Efficiency

The five-effect configuration enables multiple reuse of vapor energy, significantly reducing fresh steam consumption.

• Product Quality Protection

Low operating temperatures under vacuum conditions help minimize color formation and ensure stable product quality.

Thermal Vapor Recompression (TVR) System

The TVR system enhances energy efficiency by recompressing a portion of the secondary steam using motive steam and reusing it as heating steam in the first effect.

Benefits include:

• Reduced fresh steam consumption

• Improved overall thermal efficiency

• Lower the temperature of the live steam, providing gentler heat transfer conditions. 

• Reduced operating cost 

Cleaning System (CIP)

A fully automated Clean-In-Place system is provided to ensure hygienic operation and prevent fouling, including:

• Alkaline washing for organic residues

• Acid washing for mineral scale removal

• Hot water rinsing

Conclusion

The five-effect falling film evaporator with TVR is an advanced and energy-efficient solution for HFCS concentration. It provides an optimal balance between product quality, energy consumption, and operational stability.

The system is particularly suitable for large-scale industrial starch sugar production where consistent product quality and low operating cost are essential.

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