Sudden drop in reaction temperature, abnormal fluidization in the regeneration line
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Recently, the reaction temperature has been dropping by 3, 4, or 5 degrees without any apparent reason; the density of the regeneration inclined tubes has decreased from around 195 to around 140, and the pressure drop across the regeneration valve has also decreased – from the usual full scale of 60 kPa to lower values that are visible on the display. Then, after half a minute to twenty or thirty minutes, it returns to normal. I think the most likely cause is the detachment of the internal lining, with the lining getting stuck there; a simple fluidization issue is probably less likely. Seek guidance from experienced masters
The density of the regenerated inclined tubes is very low
By appropriately adjusting the purge air before and after the slide valve, the possibility of the lining falling onto the regeneration slide valve should be low. Also, check whether the slide valve opening and the feedback are consistent
It seems the pressure measurement point is located on the regenerative valve; I’m not sure about it either since I’m inside
Before the valve, the fluidizing medium is air, and behind it it is steam. Generally, flow control is achieved using flow restrictor plates, but some of them might be clogged and not function properly. Adjusting this is the leader’s responsibility; I don’t know if anyone has touched it. A junior worker does his job well
Checking the regenerator hot spots at night allows one to determine whether there is any liner detachment; it is possible to increase the driving force in the regeneration process or raise the regeneration pressure to ensure proper degassing of the regenerated catalytic gas. The loosening point can be adjusted according to the density of the regenerated inclined tubes, and this adjustment can be done manually.
Increase the regeneration pressure by 3-5 kPa to see the effect
Differential pressures of 30-40 have all been tried. It’s also possible that the valve opening is small at the moment. Only proper adjustment of the loose regeneration lines and backflushing of the regenerative valve, I guess.
By the way, check the fluidization medium – is it possible for the steam to contain water? Is it possible that the orifice plates at some of the fluidization points are damaged? Or perhaps opening a bypass line to adjust the fluidization in these two units represents an invisible challenge; only through numerous tests or extensive experience, along with consideration of the actual operating conditions on site, can a conclusion be drawn
If that’s the case, then the reaction temperature and pressure must also change, right?
I don’t know how many times I’ve posted Dean Lu Chunxi’s principles for adjusting the loose points; they are very practical and effective. Also, based on the data you provided, the density of your regenerative inclined tubes is indeed a bit low; here it’s generally between 300 and 500. I guess the treatment capacity at your site is relatively low! As long as the voltage drop is normal, there’s no major issue. As for the possibility of the lining falling off, I personally think that chance is also very low. Some users have advised you to check the regeneration system in your equipment, especially to see if there are any hot spots in the components related to the inclined tubes, in order to rule that out!