Carbon deposition in the reforming deoxygenation tower
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Recently, carbon deposition in our plant’s deoxidation tower has become extremely severe; the tray plates have been blocked by this carbon buildup. The temperature in the deoxidation tower isn’t very high either. Could you please tell me how carbon deposition forms inside the deoxidation tower?
I’m a bit confused; our company’s reprocessing facility doesn’t seem to have a deoxidation tower. I wonder what material the original poster’s device is made from.
We use purchased oil, and it’s inevitable for oxygen to get in during loading and unloading. Therefore, deoxygenation is carried out before pre-hydrogenation. However, coking occurs very severely inside the deoxygenation tower; I’m not sure why
Is the dryness level of the raw material a bit too high?
This post was last edited by haijiao009 on 2020-4-6 at 16:43. Could it be that there is delayed coking naphtha in the oil, which contains coke dust? I have seen coking occur in devices used to process catalytic distillate oil. Is there solid coke in the oxidation tower, or is it viscous sludge? What is the temperature in the deoxygenation tower?
The naphtha purchased from outside likely contains a significant amount of impurities; it’s not clear whether they are coke particles, as they are in solid form and quite hard. The temperature at the bottom of the tower is around 90 degrees. Additionally, the tube bundles in the pre-hydrogenation heat exchanger also tend to clog, requiring cleaning every six months or so
Olefins react with oxygen to form precursors, which undergo condensation at high temperatures in the tower; the deoxygenation tower is used to remove these impurities. In this way, the pressure drop during the pre-hydrogenation reaction slows down, allowing for longer operation cycles. If there is really too much, it is recommended to check the nitrogen seal in the tank area
At a temperature of around 90 degrees, can the precursors form solid, blocky char?
How does a deoxidation tower remove oxygen? Are there catalysts inside or any additives used?