Tubular falling film double-effect evaporator

The tubular falling film double-effect evaporator is a rapid evaporation device widely used in the food, chemical, and pharmaceutical industries for the evaporation and concentration of various solutions. The following is a detailed introduction to the tubular falling film double-effect evaporator:

1. Working Principle of the Tubular Falling Film Double-Effect Evaporator
The tubular falling film double-effect evaporator consists of two single-effect falling film evaporators connected in series. The downstream heater utilizes the waste heat of the secondary steam from the upstream effect to save on fresh steam energy consumption. The feed liquid is added from the top of the evaporator and evenly distributed into the heating tubes by a distributor. It flows down the tube wall in a film-like manner and is heated and vaporized by the heating medium (such as steam) on the shell side. The generated secondary steam and the unevaporated feed liquid enter the separator for vapor-liquid separation. The secondary steam serves as the heat source for the downstream effect, achieving heat reuse.

2. Structure of a Tubular Falling Film Double-Effect Evaporator

The tubular falling film double-effect evaporator mainly consists of an evaporator, separator, preheater, condenser, condensate tank, and circulating pump:

2.1. Evaporator: A shell-and-tube heat exchanger. The liquid material flows through the tubes, and heating steam flows through the shell. The liquid material flows down the heating tubes and is heated and evaporated.

2.2. Separator: Used to separate the secondary steam generated after heating from the concentrated liquid.

2.3. Preheater: Uses secondary steam to preheat the liquid material entering the evaporator, while simultaneously cooling the secondary steam for recycling.

2.4. Condenser: Condenses the secondary steam for recycling.

2.5. Condensate Tank: Used to collect and automatically discharge condensate.

3. Features of a Tubular Falling Film Double-Effect Evaporator

3.1 Significant Energy Saving: Energy consumption is only about half that of a typical falling film evaporator for concentration production.

3.2 High Heat Transfer Efficiency: The liquid flows down the heating tube in a film-like manner, resulting in a high heat transfer coefficient and short material residence time.

3.3 Strong Adaptability: Suitable for processing heat-sensitive materials, it can evaporate at low temperatures under vacuum negative pressure, minimizing the risk of material deterioration.

3.4 Reduced Foam Formation: The liquid is vaporized during its descent, effectively reducing foam formation.

3.5 Controllable System: Utilizing PLC programming, the equipment's process parameters can be set and controlled, and both the raw material liquid and cooling water can be automatically controlled.

4. Applications of Tubular Falling Film Double-Effect Evaporators

Tubular falling film double-effect evaporators are suitable for numerous industries, including dairy products, milk-containing beverages, plant protein beverages, tea beverages, fruit and vegetable juices, syrups, bone broth, amino acids, fermentation broths, extracts, enzymatic hydrolysates, condiments, food, bioengineering, various chemical solutions, and industrial wastewater treatment.

5. Design and Selection of Tubular Falling Film Double-Effect Evaporator

When designing a tubular falling film double-effect evaporator, process calculations such as evaporation rate, heating steam consumption, and evaporator heat transfer area must be considered. Simultaneously, the design of components such as the evaporator body, feed distributor, falling film tube arrangement, preheater, separator, lower body, heat pump, sterilizer, condenser, vacuum pump, material pump, and condensate pump must also be considered.

Through proper design and selection, the tubular falling film double-effect evaporator can achieve energy saving and stable operation while ensuring rapid evaporation, meeting the production needs of various industries.