The inlet scrubbers and flare knock-out drum have often been a problem for the facility, with heavy sludge and scale deposits that have trapped light end hydrocarbons. The typical cleaning process resulted in work stoppage and extended purging of steam through the system to void the equipment of hazardous levels of flammable gases.

After 12 hours of circulation at 70°C (140°F), the equipment was successfully descaled of inorganic deposits. The scaling was found to be mostly carbonate and sulfate scale with some iron sulfide. The iron sulfide was controlled with FQE H₂S Scavenger for hydrogen sulfide off-gasing. The flare knock-out drum was circulated with FQE Scale-Solv following the removal of the organic solids debris with the use of FQE Oil Degreaser. FQE Oil Degreaser was circulated for 18 hours at 70-80°C (140-160°F).

The knock-out drum was opened following the chemical descaling with no benzene, hydrocarbon, hydrogen sulfide, or pyrophoric iron or scale deposits remaining. The upstream de-ethanizer and de-propanizer towers were successfully degassed and de-oiled simultaneously. The wash water from each operation was sent directly to waste water treatment without delay or upset.

Upon entry, the equipment was found to be clean and acceptable for hot work. The customer stated that previous cleaning work done by two different competitors had left heavy oil residue on the equipment and detectable LEL’s.