Heat exchanger scaling
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How can a shell-and-tube heat exchanger monitor scaling on the outer walls of its heat exchange tubes? Our facility has a large number of heat exchangers, with varying specifications and service lifespans; it’s unclear when they should be cleaned
For scaling in the shell side, the inlet and outlet pipes of the shell side can be disconnected, and a flashlight can be used to examine the scaling inside through the flange. If scaling is severe, consider cleaning; it’s advisable to check once a year if possible. Clean it if possible; generally, weak acids are used to remove such scale, but the choice still depends on the material of your heat exchanger. The structure of the pipe gland is generally thoroughly cleaned using a wire brush.
Scaling in the tubes of the heat exchanger can be removed using a high-pressure water gun together with a steel rod; I clean the tubes of my titanium heaters every time they stop operating. For the shell side, it is recommended to use acid plus chemicals (corrosion inhibitors) for treatment; there are specialized companies that handle such tasks, and it is advised to carry out this treatment once a year. Scaling in both the tube side and shell side affects heat transfer efficiency and increases energy consumption.
It is necessary to compare the current heat exchange conditions with the original design data in order to establish the maintenance requirements.
It is mainly determined by observing the temperature changes of the fluid in the tube side and the shell side.
If the medium is water, scaling is more likely to occur at temperatures above 52°C
It is mainly compared with the design parameters in terms of pressure difference, flow rate, and temperature changes, taking all factors into consideration
This post was last edited by Surface treatment on 2016-12-4 at 22:46. It is possible that the inner walls of the device were not polished during manufacturing or that the polishing quality was poor; the best approach is to first perform mechanical polishing on the inner walls before moving on to electrolytic polishing (electrolytic polishing is costly but highly effective). Whether electrolytic polishing can be applied depends on the conditions on site; this is for reference only
Scaling on the outer wall of the heat exchange tubes reduces the efficiency of heat transfer, and it can lead to corrosion and perforation beneath the scale. What is a medium? What’s the temperature?