Chemical Application - FourQuest Energy

Proper chemical selection is the basis for successful cleaning, with access to a line of specialized in-house chemistry, we can seamlessly integrate the optimized set of chemistry with the correct cleaning methodology for the best results.

With endless types of chemistry in the marketplace, we understand that determining the optimized chemistry for each scope of work can be overwhelming. Using our experience, we will select a strategic set of chemistry that will best suit your needs. Our chemical cleaning arsenal includes:

  • Degreasing
  • Acid Pickling
  • Passivation
  • Heavy Hydrocarbon Removal: Solvent Based
  • Heavy Hydrocarbon Removal: Water Based
  • Decontamination
  • NORM Removal
  • Chlorination

Many of these chemical applications can be applied in series to meet multiple requirements. Some examples include:

3-Stage Degrease-Pickle-Passivation

Initial degrease to maximize pickling fluid contact, followed by a pickle to remove rust and passivation to protect surfaces before equipment is placed back into service.

2-Stage Heavy Hydrocarbon Removal – Decontamination

Initial removal of heavy sludge followed by removal of contaminants such as LELs & H2S in preparation for vessel entry and inspection.


Degreasing uses alkaline solution to remove organic matter from surfaces.  The caustic mixture normally contains other additives such as sodium meta-silicate, sodium carbonate, and surfactants and antifoaming agents to increase degreasing efficiency.

For applications where metallurgy is sensitive to chloride concentrations our specialty chemical FQE Oil Degreaser is recommended.  This is a special blend that contains emulsifier that can phase separate upon completion of decreasing.  This will concentrate oils and grease before disposal to minimize disposal costs.

Acid Pickling

Mineral Acids:  Such as hydrochloric acid, sulfamic acid, sulfuric acid, etc. are the conventional method for pickling to remove millscale and rust. These acids have varying degrees of aggressiveness and is often economical.

Chelating Agents:  Are chemistries that can bind metal ions to its molecule.  While these are not as cost-effective as mineral acids, they are inherently safer for projects where safety is a major concern.


To protect a newly pickled surface before the equipment/piping is put back into service passivation forms a layer of gamma hematite on contact surfaces by using oxidative chemistries.  This layer facilitates rust reformation after the effort of acid pickling has been conducted.

Heavy Hydrocarbon Removal: Solvent Based Flushing

Limited effectiveness has been reported for standard degreasing chemistry in extreme cases where hydrocarbon sludges contain asphaltenes and other high molecular weight organic matter. In these scenarios, FQE offers house blends of chemistry that can quickly dissolve these sticky situations.

FQE Solvent-H+ is a concentrated liquid asphaltene dispersant created from benzene free aromatic petroleum solvents containing selected dispersants, penetrants, wetting and anti-static agents.  It can quickly dissolve solid hydrocarbon deposits found in equipment such as vacuum tower bottoms.  As an added advantage, FQE Solvent-H+ has also found its use in applications where the sludge is to be recycled into process streams to minimize waste generation and maximize product recovery.

Removing Solid Asphalt Via Vapour Phase

This experiment was set up to determine the efficiency of asphaltene dissolution using FQE Solvent-H+ versus two industry alternatives and water. As evidenced in the experiment, the soluble asphaltene was completely dissolved with vapor phase application of FQE Solvent-H+. The alternatives tested essentially yielded the same results as using water (steam).

At the end of an hour, when only insoluble coke remained in the FQE beaker, a spatula was used to easily remove particulates from the beaker wall. FQE Solvent-H+ condensate was then transferred with the spatula to the other three beakers. The powerful active ingredients of FQE Solvent-H+, in condensate, was able to solubilize the deposits in the remaining beakers.

In essence, the experiment mimics decontamination of vertical vessels using a vapor phase cleaning technique. The asphalt along the side of the beakers represent heavy fouling of vessels and process equipment, easily addressed by FQE Solvent-H+.

Dissolving Crystalline Asphalt

Heavy Hydrocarbon Removal: Water Based Flushing

As an alternative, FQE Solvent-ME is water-based micro emulsion cleaner that has asphaltene, and high mole weight waxes dissolving power.  As it is water-based, it is inherently safe chemistry which can be quickly removed with a water rinse before equipment is placed back into service.


As a routine part of maintenance, many vessel and tanks require vessel entry for inspection and mechanical cleaning. These entries require safety watches and supplied air as the atmospheres can be contaminated with high concentrations of ammonia, pyrophoric ions, LELs and H2S. In order to create safer working environments, FQE can decontaminate these confined spaces with a blend of many of our house chemistries including FQE LEL-VaporFQE LEL-SurfaceFQE H2S ScavengerFQE Pyrophoric, and FQE Ammonia Odor.


For lines and vessels that are placed in service for potable water, microorganisms must be kept at an acceptable level. This is accomplished through the use of chemicals such as sodium hypochlorite and sodium thiosulfate.

NORMs Removal

When NORMs (Naturally occurring radioactive materials) concentrations in vessels and tanks reach an unacceptable level they present a health hazard to personnel who are exposed. FourQuest has a patented set of chemistry (FQE NORM-Clear and FQE NORM-Precip) that first exacts the NORM by dissolving the deposits followed by the removal of the dissolved salts to obtain radioactive free wastewater.


NORM Decontamination

FQE NORM-Clear is a water soluble product designed to completely remove NORM (normally occurring radioactive material) contamination from vessels, tanks, or process pipework.