Coking in single cyclone
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50 days after the plant started operating, the solid content in the slurry gradually increased from 4 g/L to 50 g/L, forcing the plant to shut down. An inspection of the settler and cyclone revealed that coking had formed on the outer wall of the rise pipe at the top of the settler. I would like to ask what could be the cause of this? What measures need to be taken?
Coking on the outer wall of the riser is not the cause of the solid content level. During maintenance, the cyclone was not given sufficient attention, resulting in a decrease in its efficiency and an increase in the solid content. If the solid content is not high before maintenance, it indicates that there should be no problems with the cyclone itself ； If the material leg becomes blocked during maintenance, and proper inspection is not carried out before sealing the manhole, it will result in a decrease in the efficiency of the cyclone ； Under normal circumstances, if there are no major changes in operations due to coking in the settler, it has little impact on the cyclone. We have encountered situations where, due to issues with the slurry nozzles, coking in the settler became severe; the inner diameter of the settler dropped below 1 meter, but production was not greatly affected.
It could be that the valve disc of the cyclone separator has worn out, or it might be that the rise pipe has clogged or worn out as well. There was once a situation in our plant where the solid content was over 200; it’s terrifying to think about how the oil slurry managed to wear through the components in the tower. Once the solid content in the plant rises, it’s necessary to analyze the reasons promptly. If this level remains high, it’s best to shut down the plant immediately rather than trying to keep operating it.:'(