Description
The liquid feed is introduced at the top of the calandria, where a distribution system ensures the formation of a uniform liquid film along the inner walls of the heating tubes. As the film flows downward under gravity, it is heated externally and begins to boil, partially evaporating along its path. The downward flow is further promoted by the co-current flow of vapor generated during boiling.
Separation of the remaining liquid film and vapor takes place in the lower section of the calandria and is completed in a downstream centrifugal droplet separator. To prevent dry spots—which can cause fouling and deposit accumulation—it is critical to maintain complete and even wetting of the entire heating surface. This can be achieved by using longer heating tubes, dividing the evaporator into multiple compartments, or implementing product recirculation.
Frequently Asked Questions
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What is a falling film evaporator and how does it work?
A falling film evaporator is a type of vertical shell-and-tube heat exchanger where liquid feed is introduced at the top of the calandria and flows downward as a thin film along the inner walls of the heating tubes. As the film descends under gravity, it is heated externally, causing partial evaporation. The co-current vapor flow further promotes downward movement. Liquid and vapor are then separated in the lower section and a downstream centrifugal droplet separator.
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What products are best suited for falling film evaporation?
Falling film evaporators are particularly suited for temperature-sensitive products such as dairy products, fruit juices, plant extracts, sugar solutions, and blood plasma. They are also ideal for liquids containing small quantities of solids with a low to moderate tendency to form incrustations.
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How is fouling and dry spot formation prevented in a falling film evaporator?
To prevent dry spots that can cause fouling and deposit accumulation, it is essential to maintain complete and even wetting of the entire heating surface. This can be achieved by using longer heating tubes, dividing the evaporator into multiple compartments, or implementing product recirculation systems.
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What energy-saving options are available for falling film evaporation systems?
Falling film evaporators can be designed with multiple-effect evaporation, thermal vapor recompression (TVR), or mechanical vapor recompression (MVR) to significantly improve energy efficiency and reduce operational costs. These technologies allow the reuse of vapor energy within the system, minimizing external steam consumption.
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Can the falling film evaporation system be customized for specific industrial needs?
Yes. Comprehensive customization and turnkey solutions are available, including tailored system design, layout, and material selection to meet specific client requirements. Full end-to-end support is offered, from process simulation and engineering to commissioning, operator training, and after-sales service.
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What international quality standards does the evaporation equipment comply with?
The falling film evaporation equipment undergoes rigorous testing and inspection processes aligned with internationally recognized standards including ISO, CE, and ASME. This ensures the equipment meets the highest levels of safety, performance, and regulatory compliance for global markets.