Function of Plate heat exchanger for milk
The primary function of a plate heat exchanger (PHE) in milk processing is to achieve rapid and efficient heating, cooling, and heat regeneration for pasteurization (High-Temperature Short-Time - HTST) and sterilization (UHT) processes
The PHE is highly suitable for milk due to its precise temperature control, high efficiency, and sanitary design. In a typical milk processing operation, the PHE performs several key functions across distinct sections:
1. Pasteurization and Sterilization HTST Pasteur
The main function is to heat the milk to specific temperatures for a set amount of time to kill pathogenic bacteria and extend shelf life
HTST Pasteurization : Milk is heated rapidly (e.g., to 72°C for 15 seconds) in the heating section of the PHE.
UHT Sterilization : For Ultra-High Temperature milk, the PHE can be part of a system that heats the milk to around 135°C to 140°C for a few seconds.
2. Heat Regeneration (Energy Recovery)
This is a crucial function for energy efficiency . The regeneration section uses the heat from the hot, pasteurized milk exiting the heating section to preheat the cold incoming raw milk.
The hot milk is simultaneously pre-cooled, reducing the burden on the final cooling stage,
This can recover up to 95% of the heat energy, significantly lowering operational costs
3. Cooling
After the heating and regeneration processes, the milk must be rapidly cooled to a safe storage temperature (typically below 4°C) to prevent the growth of any remaining microorganisms and maintain quality
4. Other Functions
Preheating for Separation : In some dairy operations, a PHE is used to gently preheat raw milk before it goes into a centrifuge for cream separation (standardization)
Plate heat exchangers (PHEs) are crucial in milk processing for pasteurization, cooling, and heat recovery, ensuring the product is safe for consumption, has a longer shelf life, and retains its nutritional value.
Other Applications : They are also used for processing other dairy products like cream, yogurt, and ice cream mixes, and in the production of powdered milk.
The compact, efficient design and precise temperature control of plate heat exchangers make them the most common type of heat exchanger used in modern dairy processing plants.
