Steam Coils for Heating Air To Dry Fruit

Steam Coils for Heating Air To Dry Fruit

Steam coils, as a highly efficient heating device, are widely used in fruit drying. Their core function is to heat air using steam energy, which is then used to evaporate and remove moisture from the fruit. Compared to electric and fuel-fired heating methods, steam coils offer advantages such as uniform heating, strong temperature controllability, and high thermal efficiency, making them particularly suitable for large-scale fruit drying production lines.

The process of using steam coils to heat air for fruit drying can be divided into three key steps:

Steam heat transfer: High-pressure steam (usually from a boiler) flows through the coils, transferring heat through the metal tube walls to the air outside (primarily through convection), raising the air temperature (typically from room temperature to 40-80°C, depending on the fruit variety).

Hot air circulation: Driven by a fan, the heated air enters the drying chamber, where it comes into contact with the fruit surface. The temperature gradient causes moisture within the fruit to diffuse to the surface, where it is then carried away by the hot air (which then enters the air as water vapor). Humidity control: The hot air with increased moisture content is partially discharged from the drying chamber (taking away moisture), while fresh air is replenished and reheated through the steam coil, forming a "heating-moisture absorption-exhaust" cycle until the fruit reaches the target moisture content (e.g. moisture content of raisins ≤15%, dried apples ≤20%).