Which chemical is used for tank cleaning?

For most industrial tank cleaning operations, the chemicals used depend on what residue needs to be removed. Alkaline degreasers are the most common choice for hydrocarbon and oil-based residues, while acidic cleaners tackle mineral scale, rust, and carbonate deposits. Solvents and surfactant-based solutions handle more stubborn organic compounds. The right chemical is always matched to the specific contaminant, tank material, and regulatory requirements of the site.

Choosing the wrong cleaning agent can damage tank linings, create hazardous reactions, or leave residues that compromise the next product stored. That is why tank cleaning decisions are never one-size-fits-all. This article walks through the most common questions maintenance engineers and operators face when selecting and using tank cleaning solutions in industrial settings.

What types of chemicals are used for industrial tank cleaning?

Industrial tank cleaning chemicals fall into four main categories: alkaline cleaners, acidic cleaners, solvents, and surfactant- or detergent-based solutions. Each category targets different types of residue and is selected based on the contaminant, tank material, and safety requirements of the facility.

• Alkaline cleaners (caustic soda, sodium hydroxide solutions, sodium carbonate): Effective against oils, greases, fats, and hydrocarbon residues. Widely used in petrochemical and food-grade tank cleaning.
• Acidic cleaners (hydrochloric acid, phosphoric acid, citric acid): Used to dissolve mineral scale, rust, calcium carbonate deposits, and other inorganic build-up. Commonly applied in water treatment and chemical storage tanks.
• Solvents (aromatic or aliphatic hydrocarbon solvents, alcohols): Target heavy organic compounds, resins, and polymers that resist water-based cleaning agents. Require careful handling due to flammability and vapour pressure.
• Surfactant-based detergents: Lower the surface tension between water and contaminants, making them easier to emulsify and flush away. Often combined with alkaline or acidic agents to improve cleaning efficiency.

In practice, many industrial cleaning programmes use a combination of these agents in sequence. A typical protocol might apply an alkaline degreaser first to break down hydrocarbon layers, followed by a rinse, then an acidic treatment to address any remaining scale or corrosion products. The specific sequence depends on what was stored in the tank and what condition the surface needs to be in afterwards.

How do you choose the right cleaning chemical for a tank?

Choosing the right tank cleaning solution starts with identifying the residue type, then cross-referencing it with the tank’s construction material, the product that will be stored next, and the site’s environmental and safety regulations. No single chemical works universally across all tank types and contaminants.

The key selection factors are:

• Residue chemistry: Organic, inorganic, or mixed? Oily residues respond to alkaline agents; mineral deposits to acidic ones.
• Tank material compatibility: Stainless steel tolerates a wide pH range, but carbon steel can corrode under aggressive acidic treatments. Coated or lined tanks require careful vetting of chemical compatibility with the lining.
• Next product stored: Pharmaceutical, food, or high-purity chemical tanks require cleaning agents that leave no detectable residue and are certified for use in those contexts.
• Concentration and contact time: Higher concentration does not always mean better results. Over-concentration can attack tank surfaces or create safety hazards. Contact time must be balanced against production schedules.
• Temperature requirements: Many alkaline and enzymatic cleaners perform significantly better at elevated temperatures, which affects energy consumption and equipment requirements.
• Regulatory constraints: Local discharge regulations and waste classification rules determine which chemicals can legally be used and how the resulting waste streams must be handled.

When in doubt, a chemical compatibility chart from the tank manufacturer combined with guidance from the cleaning agent supplier is the safest starting point. For complex or high-value tanks, a laboratory soak test on a material coupon before full-scale application is strongly recommended.

What are the safety risks of using chemicals in tank cleaning?

Chemical tank cleaning carries significant safety risks, including toxic vapour exposure, chemical burns, fire and explosion hazards from solvent use, and dangerous reactions between incompatible residues and cleaning agents. Confined space entry during or after chemical application adds a further layer of risk that requires strict controls.

The most serious hazards include:

• Toxic vapour accumulation: Tanks that previously held hydrocarbons, solvents, or reactive chemicals can release dangerous concentrations of vapour even after draining. Atmospheric testing for oxygen levels, flammable gases, and toxic substances is mandatory before any entry.
• Skin and eye contact: Strong acids and alkalis cause severe chemical burns. Full personal protective equipment (PPE), including chemical-resistant suits, gloves, and face shields, is non-negotiable.
• Incompatible chemical reactions: Mixing an acidic cleaner with residual alkaline material, or introducing an oxidising agent into a tank with hydrocarbon residues, can generate heat, toxic gases, or, in extreme cases, ignition.
• Confined space asphyxiation: Cleaning agents that displace oxygen or produce inert gases (such as carbon dioxide from acid-carbonate reactions) can create immediately dangerous atmospheres.

Recognised industry bodies set the safety standards that govern these operations. In the Netherlands, SIR provides guidance on industrial cleaning safety. Across Europe, EWJI (European Waterjet Industry and Users Association) addresses high-pressure and chemical cleaning protocols. In the UK, the WJA (Water Jetting Association) publishes codes of practice, while in the USA, the WJTA (WaterJet Technology Association) sets equivalent standards. In Germany, DIRV oversees industrial cleaning safety requirements. All operations should be planned and executed in compliance with the relevant body’s guidelines for the country or region where the work takes place.

When is high-pressure water jetting used instead of chemicals?

High-pressure water jetting is used instead of chemicals when the goal is mechanical removal of residue without introducing additional substances into the tank, when chemical use is restricted by environmental regulations, or when surface preparation for coating or inspection is required. Water jetting at pressures from 500 to 3,000 bar (7,252 to 43,511 PSI) can remove stubborn deposits, old coatings, and biological growth that chemicals alone cannot fully address.

There are several situations where water jetting is the preferred or required method:

• Coating removal and surface preparation: Chemicals soften or dissolve residues, but achieving the surface profile needed for coating adhesion typically requires mechanical action. Water jetting at ultra-high pressure delivers the surface roughness and cleanliness that coating manufacturers specify.
• Environmentally sensitive sites: Where chemical discharge is prohibited or heavily restricted, water jetting with full water recovery systems eliminates the need to manage chemical waste streams.
• Tanks with complex geometry: Robotic water jetting systems can access areas of a tank that manual chemical application cannot reach consistently, ensuring uniform cleaning across the entire internal surface.
• Speed-critical operations: In planned maintenance windows where turnaround time is tight, water jetting can be faster than the dwell time required for chemical cleaning cycles.
• Combination programmes: Many facilities use a chemical pre-soak to loosen bulk residue, followed by high-pressure water jetting to achieve the final surface condition. This hybrid approach reduces both chemical consumption and jetting time.

In practice, the choice between chemical cleaning and water jetting is rarely absolute. The two methods complement each other, and the optimal approach depends on the residue type, the required end condition of the tank surface, and the operational constraints of the site.

What chemical residues are hardest to remove from industrial tanks?

The hardest chemical residues to remove from industrial tanks are polymerised hydrocarbons, heavy waxy crude oil fractions, sulphur compounds, and cured resins or adhesives. These materials bond strongly to steel surfaces, resist water-based cleaning agents, and often require a combination of heat, solvent treatment, and mechanical action to fully remove.

Particularly challenging residues include:

• Asphaltenes and heavy crude fractions: Found in oil storage and refinery tanks, these high-molecular-weight compounds solidify at ambient temperatures and are nearly impervious to alkaline cleaning alone. They typically require heated solvent circulation or high-pressure jetting to break apart.
• Polymerised coatings and resins: Tanks used for monomer storage or resin production can develop hardened polymer layers that are chemically inert and mechanically very tough. Removal often requires abrasive blasting or ultra-high-pressure water jetting.
• Sulphur deposits: Common in sour crude oil tanks and some chemical process vessels, elemental sulphur deposits are resistant to most standard cleaning agents and can create hydrogen sulphide hazards during removal.
• Calcium and magnesium scale: In water treatment or process water tanks, hard mineral scale bonds tightly to surfaces and requires prolonged acid treatment or mechanical descaling.
• Biological fouling: In tanks that have held water or organic liquids over extended periods, biofilm and microbial growth can penetrate surface pitting and resist standard biocide treatment, requiring physical removal followed by disinfection.

For all of these difficult residues, the most effective approach combines the right chemistry with sufficient mechanical energy, whether from jetting pressure, recirculation, or abrasive action. Attempting to rely on chemistry alone for these residues typically results in incomplete cleaning and repeated treatments.

How do environmental regulations affect chemical tank cleaning choices?

Environmental regulations directly restrict which cleaning chemicals can be used, how the resulting waste must be classified and disposed of, and what concentration of contaminants can be present in discharge water. Non-compliance carries significant financial and legal consequences, which means regulatory requirements are often the primary driver of cleaning method selection, not just one factor among many.

The main regulatory impacts on tank cleaning solutions are:

• Restricted substances lists: Many jurisdictions prohibit or strictly limit the use of certain solvents, phosphate-based detergents, and halogenated compounds. The EU’s REACH regulation and equivalent frameworks in other regions require facilities to substitute restricted substances with compliant alternatives.
• Wastewater discharge limits: Cleaning effluent containing hydrocarbons, heavy metals, or high concentrations of cleaning agents cannot be discharged to drain without treatment. Facilities must either treat the effluent on-site or arrange for specialist waste contractor collection, both of which add cost and logistical complexity.
• Volatile organic compound (VOC) restrictions: Solvent-based cleaners release VOCs during application, which are regulated under air quality legislation in most industrialised countries. Low-VOC or aqueous alternatives are increasingly required.
• Waste classification: Spent cleaning chemicals mixed with tank residues are often classified as hazardous waste, triggering strict handling, storage, transport, and disposal obligations.

The regulatory landscape is pushing many facilities toward water-based cleaning systems with closed-loop water recovery, which minimise both chemical use and waste volumes. High-pressure water jetting with full effluent capture is increasingly favoured precisely because it reduces the regulatory burden associated with chemical cleaning programmes.

How MagTrack Supports Industrial Tank Cleaning

When chemical cleaning alone is not enough, or when regulations restrict chemical use entirely, robotic water jetting delivers the mechanical cleaning power that tanks require. We developed the DERC MagTrack system specifically to meet this need in demanding industrial environments.

MagTrack is a modular magnetic crawler robot, electrically driven, designed for use on flat and slightly curved steel surfaces. It is a direct answer to the challenges that maintenance engineers and operators face when cleaning oil storage tanks, cargo holds, and industrial vessels:

• Closed waterblasting with full debris recovery: The MagTrack Blast Can (vacuum dome) collects both water and loosened residue without leakage, leaving a clean, dry surface ready for inspection or coating. This eliminates the need to manage large volumes of chemical-laden effluent.
• High-pressure performance: MagTrack tools operate at up to 3,000 bar (43,511 PSI), delivering the mechanical energy needed to remove polymerised hydrocarbons, heavy scale, and cured residues that resist chemical treatment alone.
• Curved surface capability: The Curved Blast Can variant handles surfaces with a radius of up to 3 meters (9.8 feet), making it suitable for small storage tanks and the curved contours of ship hulls.
• Compact access for confined spaces: The MagTrack Mini is a lightweight, remote-controlled crawler designed for narrow spaces, including offshore oil rigs, available as a certified ATEX Zone 2 unit for use in hazardous atmospheres.
• Reduced operator exposure: By keeping personnel out of confined, chemically contaminated tank environments, MagTrack directly addresses the safety risks associated with manual tank cleaning operations.

If your facility is dealing with difficult residues, tight regulatory requirements, or the need to reduce chemical waste streams, we would be glad to discuss how MagTrack can be configured for your specific application. Contact our team to talk through your tank cleaning challenges with our engineers.