The main reasons for the ice cracking of plate heat exchangers

The main reasons for the ice cracking of plate heat exchangers are as follows:

Incomplete drainage of water

- In a cold environment, if the water inside the plate heat exchanger is not drained completely after it is deactivated, when the temperature drops below the freezing point, the water freezes and its volume expands by approximately 9%. The resulting expansion force will exert tremendous pressure on the plates and seals of the heat exchanger, thereby causing ice cracking.
 

Low-temperature operation

- When the plate heat exchanger operates under low-temperature conditions, if the fluid temperature is too low and the flow rate is slow, local freezing may occur. The formation of ice will damage the internal structure of the heat exchanger and trigger ice cracking.
- The excessively low surrounding environmental temperature may also affect the temperature of the heat exchanger. Especially in the absence of appropriate insulation measures, the surface temperature of the equipment drops rapidly, causing the internal water to freeze.

Improper design and selection

- If the working conditions are not fully considered during the design process, for example, the estimated minimum temperature is inaccurate, and the selected material or structure of the plate heat exchanger is unable to adapt to the actual possible low-temperature environment, ice cracking is prone to occur at low temperatures.
- An undersized selection leads to an excessively long residence time of the fluid in the heat exchanger and excessive heat exchange, which also increases the risk of freezing.

Operation problems

- During the start-up and shutdown processes, if the operation is improper, for example, introducing low-temperature fluid into the heat exchanger rapidly, or putting it into use before the system is fully preheated, it will cause uneven temperature changes in various parts of the heat exchanger, generating thermal stress. Acting together with the freezing expansion force, it increases the possibility of ice cracking.
- For plate heat exchangers with multiple processes, if the flow distribution among the processes is uneven, it may cause the fluid flow rate in some areas to be too low and freeze.

Water quality issues

- If the water contains impurities, minerals, etc., it may affect the freezing point of the water, causing it to freeze at a relatively high temperature. At the same time, impurities may also clog the channels of the heat exchanger, resulting in poor local water flow and an increased likelihood of freezing and ice cracking.

Insufficient maintenance

- After long-term use, the inside of the plate heat exchanger may accumulate scale, affecting the heat transfer efficiency and causing local temperatures to be too low and freeze.
- Failure to timely inspect and replace aged and damaged seals may cause water leakage due to poor sealing at low temperatures. The leaked water freezes on the outside and damages the structure of the heat exchanger.

Shanghai KUB Refrigeration Equipment Co., Ltd.

Free Call Video Chat