Technical discussion: Scaling issue in chilled water pipes
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This post was last edited by hesonchang214 on 2010-6-3 09:54. During maintenance a few days ago, severe scaling was found on the low-temperature water pipes of the chiller. Has anyone else experienced a similar issue? How can it be resolved, or how can this problem be avoided in the future?
Control the quality of the chilled water. If possible, use pure water as the feed water for the chiller unit. Consider adding a certain amount of corrosion inhibitor
Alternatively, an external flow cation-anion exchanger can be added; if an external filter is used, there is no need to add chemicals.
Chilled water generally does not scale easily; the main function is corrosion inhibition. The severe scaling in your chilled water indicates that the calcium and magnesium ions in the make-up water have high levels. Please explain what kind of water you use as make-up water. To resolve or avoid such problems, first, the system should be cleaned and pre-coated; second, in addition to adding corrosion inhibitors, scale inhibitors must also be added. Since the corrosion inhibitors used in chilled water are often strong oxidizing agents, the formula for the scale inhibitors used is different from that used in ordinary circulating water. Third, the supplementary water used is deionized water, primarily to remove calcium and magnesium ions.
This post was last edited by cdpulin on 2010-7-5 at 14:10; distilled water is the best choice for adding water.
Adding another sodium-ion exchange water softener will solve the problem; in this way, all the water used for replenishing the system will be softened water free of calcium and magnesium ions, preventing scale formation
It is best to find a professional water treatment company to provide technical support and chemicals; this is the optimal choice.
This is likely due to high levels of calcium and magnesium ions in the water, but chilled water generally does not tend to form scale; its main function is corrosion inhibition. To resolve or avoid such problems, first, the water used must have its calcium and magnesium ions removed; second, the system pipes need to be cleaned and coated with a protective layer (using corrosion and scale inhibition agents). The corrosion inhibitors for chilled water are mostly strong oxidizing agents; therefore, the scale inhibitors added are different from those used in ordinary circulating water systems. Otherwise, the pipes are very likely to get damaged. If possible, it’s better to use demineralized water.
1. Scale inhibitors can be added or soft water can be used. 2. It is possible that, due to a high concentration ratio, salt crystals form at low temperatures, resulting in scale formation. Pay attention to controlling the concentration ratio and increase water replenishment and drainage; it is advisable to provide specific water quality data
Control the quality of the chilled water. If possible, use pure water as the feed water for the chiller unit. Consider adding a certain amount of corrosion inhibitor