Selection of materials for the tube sheet and shell of graywater heaters
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Is the tube sheet material for graywater heaters generally made of carbon steel composite? The shell-side fluid is flash vapor, while the tube-side fluid is graywater. It seems that the current design specifies a corrosion margin of around 6 mm for the shell-side material; the material used is carbon steel, while the tube-side material is duplex steel. Yes, 316L is also used. I’m not sure just how severe the corrosion caused by vapor is; what problems could arise if carbon steel composite plates are used for the shell side? And for the tube sheet material, is it possible to use all stainless steel?
In my opinion, there is no need to use duplex steel for the tube side of gray water heaters – it’s too wasteful. From a corrosion prevention perspective, since carbon steel can be used for the tube side, it can also be used for the heat exchange tubes, and there are actual examples of such applications. As for the corrosion caused by flash vapor, I believe it is largely related to the type of coal used. In fact, blockages and scaling in the ash water heaters are far more common problems than corrosion; addressing these issues of scaling and blockage is the key to solving the problem. Just my opinion; let’s discuss it together.
As I understand it, scaling mainly occurs on the surface of the heat exchange tubes? In other words, regarding the materials of the cylinder and tube sheet, the corrosion of the flash vapor (acid corrosion? ) It doesn’t need to be considered, so carbon steel can be used?