A crude heater at Atofina’s Port Arthur, Texas facility had unexpectedly coked solid. With zero flow, traditional steam-air de-coking procedures would be impossible. Fortunately, we had extensive experience in coke removal. Since the tubes were totally blocked, the engineering department concluded that Hydrokinetics offered the only viable solution. If we couldn’t do it, it couldn’t be done.
We dispatched our crew and commenced the Hydrokinetics process. After 15 minutes, we noticed significant pressure spikes at 1,100 PSI, followed by a return to normal discharge pressure. This happened five times in rapid succession. We then noticed flow coming through the vacuum line at the outlet end with a considerable amount of coke solids and crude residues. Finally, our system became static with pressure maintained at 4,100 PSI, indicating that the foulant had stopped moving.
Following procedure, we reversed the process from the outlet side into the inlet. Doing this repeatedly, we expelled a large volume of coke and water from the tubes. On the final cycle, a large quantity of burned oil, along with the remaining coke, was ejected. The heater then was allowed to flush. Plastic wadding was inserted into the tubes and re-flushed, followed by medium-density power pigs, then extremely rigid power pigs, specially manufactured for the Hydrokinetics process. Based on the heater reaction and the amount of coke expelled, we determined that 50-60 percent of the tube volume was coked solid.
The entire cleaning process took only 12 hours, compared to the estimated 10 days to cut out and replace the plugged pass of the heater. Examination of the coke chunks and piping revealed that the heater was so clean, steam-air de-coking would be unnecessary, saving the plant an additional 26 hours in downtime.
