Chemical Decontamination of Gas Separation Towers and Heat Exchangers

Results Achieved

Benzene and hydrocarbon free

Zero LELs after 18 hours of circulation

No inorganic scales remaining

Waste water treatment compatible

Chemical profiles


Created for the dissolution and recovery of asphaltenes in process equipment, pipelines and storage tanks.

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Rapid absorption of vapor-state hydrocarbons in an innovative encapsulant for effective decontamination and degassing of hydrocarbon processing equipment.

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Designed for instantaneous and permanent elimination of Hydrogen Sulfide present in refining and other process equipment.

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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 ethylene plant used our decontamination products FQE™ LEL-V, FQE™ Solvent-H, FQE™ H2S and FQE™ Scale-Solv to prepare their quench water towers (T-1401/1501), cold-end separation towers, heat exchangers and flare knock-out drum for maintenance.


The equipment required degassing, heavy tar removal and descaling of water-born scales. Flare knock-out drums were contaminated with heavy tars from entrained asphaltenes and waxes. The heavy sludge had been a problem for the facility, as deposits that have trapped light end hydrocarbons made vessel entry unsafe. 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.


The flare knock drums were circulated with diesel oil containing 5% FQE Solvent-H for 24 hours at 71°C (160°F) and drained. Following the solvent circulation, the drums were circulated with a combination of FQE LEL-V and FQE Scale-Solv to degas and descale the equipment.


After 12 hours of circulation at 60°C (140°F), the equipment was successfully descaled of inorganic deposits and was at zero LEL. The scaling was found to be mostly carbonate and sulfate scale with some iron sulfide. The iron sulfide was controlled by use of FQE H2S for hydrogen sulfide off-gassing. The heat exchangers and all associated piping were circulated with FQE LEL-V and FQE Scale-Solv to simultaneously de-oil and descale the equipment. The upstream de-ethanizer and de-propanizer towers were successfully degassed and de-oiled simultaneously.


Both quench water towers were decontaminated with FQE LEL-V and FQE Scale-Solv using a cascade circulation at 60-70°C (140-150°F). The quench water system was circulated through the towers, exchangers, and piping to remove water-born scale deposits. The wash water from each operation was sent directly to waste water treatment without delay or upset. Upon inspection, the equipment was found to be clean and acceptable for hot work.

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