Vacuum Drying Evaporator Coil

Vacuum Drying Evaporator Coil

In the process of vacuum drying, evaporator usually refers to the key equipment used to deal with the water vapor produced by material evaporation, and its core function is to convert water vapor into liquid water through condensation (recovering water), while maintaining the vacuum environment of the system (avoiding the accumulation of water vapor leading to pressure rise), and recovering latent heat released by condensation of water vapor in some scenarios. It works in concert with vacuum dryers, vacuum pumps and other equipment, and is one of the core components to ensure vacuum drying efficiency and energy consumption.

The principle of vacuum drying is to reduce the boiling point of water (or solvent) in the material by lowering the pressure of the system (vacuum environment), and evaporate it quickly at a lower temperature (to avoid deterioration of heat-sensitive materials). Evaporation of the water vapor produced if not handled in a timely manner, will lead to increased system pressure, damage to the vacuum environment and reduce the drying efficiency. Therefore, the core role of the evaporator is to:

Condense water vapor: cool the evaporated water vapor from the material to liquid water, which is discharged from the system to avoid accumulation of water vapor.

Maintaining vacuum: By continuously removing water vapor, the system is maintained at a low pressure (typically 0.1-10 kPa, depending on drying requirements) in conjunction with a vacuum pump.

Latent heat recovery (optional): A large amount of latent heat is released when water vapor condenses, and the evaporator can be designed to recover this heat (e.g., by heating cold water or as an auxiliary heat source), thus reducing the energy consumption of the system.

Application Scenario

Pharmaceutical industry: vacuum drying of antibiotics, vaccines and other heat-sensitive materials, the evaporator needs to be made of stainless steel (in line with GMP standards) to avoid contamination.

Food industry: vacuum drying of fruit and vegetable slices, milk powder, the water condensed by the evaporator can be recovered as process water (aseptic design is required).

Chemical industry: the recovery of organic solvents (such as ethanol, acetone), the evaporator needs to be resistant to solvent corrosion (such as the use of Hastelloy material).

Environmental protection industry: sludge, hazardous waste vacuum drying, the evaporator needs to adapt to high humidity, impurity-containing water vapor, focusing on anti-clogging design.