What are the main causes of scaling in U-tube heat exchangers?
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The heat exchange efficiency of the company’s heat exchangers has recently declined significantly, with a decrease of about 0.5% per month. Is this caused by scaling, and how can it be effectively prevented?
Don’t generalize. To analyze the causes of scaling, it is necessary to gather experience and measures from similar installations that have dealt with similar incidents, and develop a treatment plan based on one’s own specific conditions.
1 Heat exchanger structure: Flow velocity is restricted, resulting in slow flow rates and easy sedimentation of the medium； 2 The medium itself: suspension property, tendency to form scale
Check if there is a leak or a change in flow rate; the flow has decreased
If possible, shut down the machine to check the specific situation
Based on the data you provided, the heat exchange efficiency decreases by 0.5% per month; it is preliminarily estimated that this is caused by scaling, as a 1mm thick layer of scale can reduce heat exchange efficiency by 10%–15%. The situation you described is consistent with the gradual buildup of scale; it is necessary to clean the equipment to remove this scale. After that, relevant devices can be installed for water treatment, or electromagnetic scale prevention and removal devices can be tried. Contact us if you have any other questions
Structural tendencies of the medium and components, operating temperature, flow rate, flow pattern, flow volume......
Using threaded tubes or corrugated tubes should help with the scaling problem.
Pay attention to water quality; scaling makes cleaning more difficult. The shell side is usually not visible, so care must be taken during cleaning to avoid damaging it.
1. Pay attention to water quality and reduce internal scaling； 2. Pay attention to the flow rate to prevent the accumulation of scale and debris in localized areas, especially at the bottom of the U-shaped section ； 3. Pay attention to the fact that the flow rate results in a lower temperature on the outer wall of the pipeline, causing this temperature to be below the melting point of the scale formed by the heat source, which in turn leads to scaling on the outer wall ； 4. Pay attention to the heat source temperature, heat source utilization rate, and medium heat exchange ratio to prevent scaling on the outer wall. I specialize in coatings, so I can only offer suggestions for improvements using coatings. Acid-resistant, heat-conductive, and anti-corrosion coatings can be applied; such coatings increase heat radiation absorption, raise the temperature of the pipe walls, and reduce scaling on the outer surface.