Falling Film Evaporator

Evaporation is an operation that heats the solution in a concentrator to its boiling point, vaporizes and removes part of the solvent to increase the solution concentration. It is also a separation process between the volatile solvent and non-volatile solute in the solution. The equipment used to achieve evaporation is called an evaporator, also known as a concentrator. Therefore, a falling film evaporator is also referred to as a falling film concentrator.

The falling film evaporator is a type of evaporator that adopts single-effect falling film evaporation. The feed liquid is added from the upper header of the heating chamber of the falling film evaporator, evenly distributed into each heat exchange tube through a liquid distribution and film-forming device, and flows downward in a uniform film shape under the action of gravity, vacuum induction, and air flow. During the flow process, it is heated and vaporized by the heating medium in the shell side. The generated vapor and liquid phase jointly enter the separation chamber of the evaporator. After sufficient vapor-liquid separation, the vapor enters the condenser for condensation (single-effect operation) or enters the next-effect evaporator as a heating medium to achieve multi-effect operation, while the liquid phase is discharged from the separation chamber.

The main body of the equipment consists of a single-effect heater, single-effect separator, thermocompressor, condenser, sterilizer, heat preservation pipe, material pump, water pump, drainage system, steam header, operation table, electrical instrument control cabinet, valves, and pipelines. Falling film evaporators are suitable for low-temperature concentration in food, chemical, and environmental protection industries, such as milk, glucose, starch, xylose, etc.

The falling film evaporator adopts a long-tube heater. During evaporation, the material is evenly distributed inside the tubes by a distributor, forming a film that descends. With short evaporation time, it can achieve the required concentration in a single pass, making it a high-efficiency continuous evaporator. The interior and exterior of the equipment are precisely polished, complying with GMP requirements.

For the single-effect falling film evaporator, the feed liquid is added from the top of the evaporator, forming a film that descends along the tube wall under the action of gravity. During this process, the liquid evaporates and concentrates, with the concentrated solution obtained at the bottom. The single-effect falling film evaporator can handle materials with relatively high concentration and viscosity (e.g., within the range of 0.05–0.45 N·s/m²). It operates under vacuum decompression, featuring low evaporation temperature and high speed. The instruments and valves are rationally configured for convenient operation.