Chemical Decontamination of Flare Line and Knock Out Drum

Results Achieved

75% reduction in down time  

Over $100,000 in maintenance cost savings

Zero LEL and zero benzene after 36 hours

No hazardous waste and over 90% recovered hydrocarbon content

Chemical profiles


Water-based, low flash point, pleasant orange aroma, potent solvent for dissolving greases and hydrocarbon solids in refinery equipment.



A moderately acidic premium cleaning compound designed for removal of water-born scales that are not removed easily by coordination nor typical inhibited mineral acids.

A large petroleum refining company in Brazil used FQE™ Degreaser-L and FQE™ Scale-Solv products to decontaminate and clean the flare line and knock-out drum.


The drum was estimated to be 1/3 full of organic and inorganic solids. Analysis of the drum contents showed the bottom debris to be 82% solids and 18% liquid entrained within the solids. Of the solid contents, 38% were a mixture of inorganic salts (mostly iron oxide, calcium, and magnesium chlorides and carbonates). The balance of the solids were wax and asphaltenes, with some liquid hydrocarbon.


The knock-out drum was circulated with light cycle oil containing 5% FQE Degreaser-L to fluidize the wax and asphaltic solids. The circulation was performed over 18 hours at 66°C (150°F). 1,500 feet of flare piping leading to the drum were also included in circulation. Afterward, the liquid was drained and sent to the refinery slop oil tank for hydrocarbon recovery.


After the removal of the organic debris, the flare line and drum were circulated with a 10% aqueous mixture of FQE Scale-Solv at 60-65°C (140-150°F) for 15 hours. The circulation liquids were monitored for density and pH to ensure the removal of the inorganic contents. On completion, the equipment was inspected and found to contain minimal inorganic solids that were easily vacuumed out without adhering to the vessel walls. The vessel was free of oils and oily solids.


In prior cleaning trials, it took several days to evacuate system of organic and inorganic debris by mechanical means. The plant estimated that over $100,000 was saved over the conventional method.

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