[Heat Exchange Equipment] Talking about things at work (September 19th---25th)
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How to participate: Share real stories from this week’s work that involve technology, installation, maintenance, etc. (Share the technical problems you encounter at work, along with the methods you used to solve them, so that others can benefit from your experience. You can also discuss any difficulties or challenges you face, and those who struggle to express things in words can send actual images for everyone to analyze together.) Response requirement: Members are asked to share their own experiences regarding their work this week. Example 1: Today, our XXX pump broke down, so we organized repairs. Upon disassembly, it turned out that the bearing sleeve was worn out. Install after replacing the shaft sleeve. (One can continue to analyze the reasons and so on, or end it here.) Example 2: I received a new design task today – a shell-and-tube heat exchanger, which is very simple. No particularly difficult structures have been found for now. We hope everyone will participate actively{:1_90:}. A quick reminder: the events must have taken place this week and be related to this forum. A normal reply would be 5 points of wealth; if a detailed description is possible, it could be 10 to 15 points of wealth
I’m completely puzzled: A few days ago I was given a design task involving six types of air coolers – plug-type tube banks, that is, rectangular tube banks. The designed temperature for these coolers is 250°C, and the operating pressure ranges from 0.7 to 1.6 MPa. Yet the client insisted that the design pressure should be set at 2.6 MPa. According to any standard, such a high design pressure isn’t necessary; isn’t this a waste of resources?
The reboiler of the distillation tower leaked, causing the methanol level in the steam system to exceed the limits. Inspection revealed leaks at the welds of the tube bundles; the possible cause is that excessive stress was applied to the welded areas due to thermal expansion, resulting in cracks in those welds. Or the corrosion is severe, making the weld area prone to corrosion.
Today, I am designing a fixed-tube-sheet heat exchanger. The process specifications do not provide the wall temperature of the shell nor that of the heat exchange tubes. Fellow engineers, how do you determine these two temperatures? If the formula in Appendix F of GB151 is used, how should the process parameters (such as αh) be determined?
It could be due to other reasons; for example, the pump’s head or operating conditions such as equipment cleaning may require such high pressure.
This post was last edited by wangtianyi*ao on 2011-9-21 at 12:59. Forget it; just talking about it makes me frustrated! The process department sent over the specifications for a phosphoric acid storage tank, requiring that we produce the design drawings within two days. The manager said that due to the urgency, there was no paper version available; the specifications were sent electronically instead. Moreover, the device identifiers and names were incorrect, so I was told to work based on the device schematic diagrams and the list of pipe connections. Well, I’ll do it. I spent the whole day working overtime and staying up late, sent it over, only to be told that the diagram in the equipment specifications table was incorrect! ! ! The image is 2000x2000, but it’s said that the result should be 3500x3500. There were originally 5 connectors, but now they say that so many aren’t needed. I’m puzzled – what’s the point of their manufacturing process? It doesn’t take ten minutes to put forward a requirement; errors can occur in the tag numbers, names, dimensions, the orientation and quantity of connectors, or even the drawing numbers. What kind of \"requirement\" is that? All day long they keep shouting to follow the procedures, follow the procedures – just stick to the procedures? ? It was the same last time too: they brought in a drawing and started complaining that the dimensions needed to be changed. They just told us to make the changes without knowing exactly what was required, and as a result the changes were done incorrectly. We ended up having to pay a fine of 50 – is that acceptable? Coming here again like this – no reward is expected, but it can’t be done this way either! There’s nothing to do; after all, we’re employees. Let’s rewrite it again. I’m not in a hurry to work overtime on this; whatever happens, it’s fine. No one can tolerate this situation.