Large temperature fluctuations in the catalytic reforming stabilizer?
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Hello everyone, I would like to ask you all a question. The temperature of the stabilizer tower in our unit has been fluctuating greatly recently. It is the stabilizer column of a catalytic reforming unit; the typical control value is around 45 degrees, while the temperature fluctuation in this column is generally between 38 and 60 degrees. It only started to fluctuate recently. Everything was normal before; now, with these fluctuations, the saturated vapor pressure of gasoline is extremely high, and the carbon-5 content in liquefied gas is also increased. The feed also does not contain water, and despite multiple attempts at adjustment, the situation has not improved. This tower functions normally during the summer; it’s just unclear what’s going on recently. This tower was flooded twice; it is a floating valve tray tower. I think it’s the flooding of the tower that has caused problems with the trays, resulting in a poor separation capacity of the tower; or could there be other reasons? I would appreciate some advice from those who know more about this. Thank you.
Our units also experience high levels of carbon 5 in the liquefied gas. The solution we adopt is to isolate the stabilizer tower, use a reflux pump to inject water, wash the tower with water, and then strictly control the relevant parameters, which ensures that the carbon 5 level becomes acceptable. You said that your tower was flooded twice; could it be that due to these floods, there was a lot of buildup on the tray, preventing the floating valves from functioning properly, which in turn reduced the tower’s separation efficiency? I think that’s probably the case too; try washing the stabilizer tower with water.
There are fluctuations in the tower temperature; it’s unknown what the feed temperature is. Have there been any recent fluctuations in the bottom of the tower temperature, reflux temperature, and reflux volume? A high vapor pressure of gasoline along with a high C5 content in the liquefied gas indicate that the separation efficiency has declined. Check whether there is a problem with the reflux volume – could it be that the automatic control system is not functioning properly?
I also encountered situations in my column where the carbon-5 content in the liquefied gas was high; at that time, both the column pressure and the top temperature fluctuated significantly. Upon further investigation, it was found that salt had accumulated on the column trays, and after using a washing method, the quality of the liquefied gas became satisfactory.
Once the load on the stabilizer tower becomes too high, it is easy for salt to accumulate on the tray when the feed material has a high salt content
This indicates that salt has accumulated on the trays; a small amount of deoxygenated water or steam at a pressure higher than that in the tower can be injected to wash away the salt buildup inside the tower. When operating, be careful not to inject too large a volume at once, to avoid affecting the normal operation of the tower.
Ammonium salt crystals – just rinse them with water; it’s no big deal. :lol
Oh, I’ve never encountered this situation with the stabilization tower before; it’s quite enlightening to learn that an excessive load on the temperature stabilization tower can also lead to salt buildup on the trays! ! !
1. First, check whether the instruments are functioning properly and whether the 3-way mixing valve is operating correctly. 2. Check if the temperature in the distillation column is too high; high temperatures can cause gases to circulate between V302 and the distillation column. Also, verify whether the flow rate of the gas exiting the distillation column exceeds the set parameters. 3. Check whether the flow rate of the cold return stream is normal. 4. Check whether the pressure control valve in the stabilization column is functioning properly, as well as whether all three valves operate together. Excessive opening of the hot path or the cold path can lead to pressure fluctuations. 5. Finally, decide whether it’s necessary to clean the column. This is just my opinion; please feel free to give your feedback
Personally, I think it might be a problem with the tray. If that’s ruled out, then check whether there are any issues with pressure control