2 replies to this topic

[Axis and Matrix]

Good day everyone.

I am an Operations Engineer from a refinery here in Asia. Our crude charge pumps were found to have deposits thrice in 7 months causing high amperage to the motor drivers. Consequently, this necessitated the decrease in our pipestill feedrate thus affecting our programmed crude run. We tested the deposits and found out that these were mainly composed of sodium salts. Please see attached file for the simplified process flow diagram of the crude charge pump system.

In order to address this, we recommended and applied caustic dilution to the system from 25 deg Be to 8-10 deg Be in order to avoid unreacted concentrated caustic freely moving in the system which later may react with freely moving ions from crude and water.

However, even after the implementation of caustic dilution, high motor current was still observed. Pump impeller was pulled out and deposits were found again on the impeller.

Sludge migration was one of the possible causes of the deposition however, during the time of the incident, crude was being fed at elevated suction from crude tanks. We are also suspecting asphaltene formation as a possible cause.

Have you had any experience similar to this? What are the possible causes that may bring this incident about?

Thanks and best regards.

Attached Files

•  Crude Charge Pump Process Flow.png   17.14KB   10 downloads

[LVBob]

Hello Axis and Matrix.

You might want to consider doing the following:

- Plot specific crude shipments with time. Identify possible crude slates that were charged into the pipestills at the specific dates during which you encountered the fouling incident.

- If it is not crude-related, it might be the pipelines. Check reports of the personnel handling the crude tanks. They may have used some idle (and dirty) lines during that time.

- Check also if they switched booster pumps. I'm not sure how probable this might be but something similar occurred to my unit. They switched to an idle pump after experiencing some problems with the running pump. The idle pump was not in use for almost a year i think. Corrosion material had already accumulated in the pump.

Hope this helps. Good luck.

[Axis and Matrix]

Thanks for the response. Yes, we will check on these.

Regards,