Cracks appear in the shell side of the steam drum
Thread Content
In the low-pressure drum, the liquid level is always very low during operation; it’s not possible to adjust the liquid level, and this affects the temperature at the outlet of the tube side, thereby impacting production. Cracks have occurred several times after the shell side was replaced. I would like to know what effect the length of the drum’s tube bundle has. In my opinion, if the tube bundle is too short, it leads to a large temperature difference between the two ends of the shell side, resulting in high thermal stress. Do any of you have other opinions? I would appreciate your insights
This schematic diagram does not seem coherent: 1. The diameter of the gas outlet at the shell side is 1M, which indicates that the volume of gas is significant, or perhaps a high ratio of gas to liquid is required? 2. With such a short tube bundle, there will inevitably be a lot of space in the shell side that remains unheated, and the heating is also suboptimal ； 3. Thermal stress causes cracks, but since it is a U-tube, where is the stress area? It’s not a tube sheet, nor a tube end – it’s just a crack in the shell weld, so what the original poster suggested is possible. In short: this device is very strange. . a. If the area requirement is not high, it is more appropriate to arrange the tubes more sparsely and use larger tube diameters, with the length extending throughout the shell cavity. b. If the requirement for gas-liquid entrainment is very high, can the shell be made larger?
If the temperature difference between the hot and cold media is large, intense boiling may occur in the R section of the heat exchange tube, and the formation of bubbles can cause significant damage. It’s just a guess
Half of the tube bundle is in the gas phase and half in the liquid phase, so the temperature difference stress must be high; adjust the operating parameters so that the liquid level covers the tube bundle.
The height of the row of tubes is significantly higher than that of the tube bundle.
Is the material chosen during the manufacturing process also one of the factors to be considered?
One is mixed heating, and the other is surface heating; it’s better to keep them separate, just as in power plants where the deaerator and surface heaters are separated, which makes it easier to solve problems