Exchange of experience on the long-term operation of catalytic units
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I was wondering if there are any catalytic units that have been in operation for more than three years. If so, I would appreciate it if you could share your practical skills and experiences; we can exchange ideas on the problems of coking in the reactor and the distillation column during long-term operation of catalytic systems
Of course. It’s the case in Dalian – generally, inspections are carried out every two years. Corrosion inhibitors are added to the distillation tower, and care should be taken when starting up the sedimentator, in order to minimize the number of unplanned shutdowns! !
We also conduct inspections every three years. The issues of carbon deposition in the settlers and fractional distillation towers mentioned by the poster are not a problem for us, as very little carbon deposition occurs in these areas after each inspection; only a small amount of coke forms, which does not affect the long-term operation of the facility. Issues with the reverse *art equipment affect us quite a lot. Issues such as air cooling efficiency, compressor vibration, heat exchanger scaling, and pipeline corrosion and leakage cause us a great deal of trouble.
It has been almost 4 years in this cycle, and coking problems in the distillation tower have hardly occurred, mainly due to strict control of the temperature at the bottom of the distillation tower. One set of slurry steam generators is in operation, with another set as a backup, to ensure the linear velocity of the slurry system. A stream of agitated slurry is introduced at the bottom of the distillation column to prevent coking in the dead zone at the bottom. At the same time, proper dosing of the slurry scale inhibitor is also crucial. The liquid level at the bottom of the distillation tower should not be too high; it should be kept low as much as possible while ensuring safety, in order to reduce the residence time of the oil slurry inside the tower. Finally, strengthen the monitoring of raw materials, slag mixing ratio, and the discharged oil slurry; discharge more of it if necessary. :)