Reactor bottom vapor pressure
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This post was last edited by chinazwr on 2009-5-12 at 19:42. I have a question for everyone: I work at a newly built factory, and recently a strange phenomenon has occurred – the vapor pressure in the tower bottom sometimes becomes negative. Please help to explain it, thank you! !
Based on experience, it seems to be a gauge failure; we need them to come and check before we can be sure.
The instruments are fine; if the pressure gauge is removed, one can feel the air intake by touching it
Post the process for this section; it would be best to have relevant pipeline layout diagrams so that a detailed analysis can be conducted. Also, when the situation mentioned by LZ occurs, is it in a normal production state? This post was last edited by bigelephat on 2008-3-4 09:33]
There are three factors to consider: 1. Calibration of the pressure gauge; 2. Whether the installation diagram of the process pipelines is reasonable; 3. Any special conditions in production
What was said on the 5th floor makes a lot of sense; it’s still necessary to make judgments based on the specific process parameters and procedures. There’s also the issue of instrument readings – I wonder if it’s possible to compare the readings from instruments on-site with those in the control room.
Since it’s exhalation, it has nothing to do with the instruments; let’s take a look at the process instead
Thank you all! I’ll upload the images in the next couple of days; this phenomenon occurs during normal production
Check the processes and pipelines; there may be leaks that cause siphoning.
This is possible; it is estimated that at this time the material being heated is below 100°C, and the amount of steam supplied is low while the heating surface area is large, or the system may be shut down. In such cases, if the condensation rate inside the reboiler heater is greater than the rate at which steam enters, and since there are few non-condensable gases, the temperature of the condensed steam water is below 100°C. The pressure in the heater chamber at this point is close to the saturated vapor pressure of the condensed water. As a result, the temperature of the condensed water remains below 100°C, and the saturated vapor pressure of water at 100°C is 0 psig. Since the temperature of the condensed water is below 100°C, this means that a vacuum, or negative pressure, has formed inside the heater. In the heater of the first-stage evaporator of the double-effect evaporation system in our facility, the pressure is basically around 0; it is sometimes slightly positive and sometimes slightly negative, which is a normal phenomenon.
In my opinion, there are several possible explanations: one possibility is that the pressure measurement point is located near the feed inlet, and the fast flow rate at the feed inlet creates a negative pressure in that area； The second possibility is that construction factors cause a reduction in diameter ahead of the pressure tapping point, resulting in negative pressure at that tapping point ； The third possibility is that there is a feed inlet near the pressure tapping point, and the feed temperature is unstable; negative pressure occurs when the feed temperature is low, while positive pressure appears when the feed temperature is high or normal! !