Protecting Turbine Blades from the Inside Out: How Low Free Metal Ion Surfactants Prevent Hot Spots and Hot Corrosion
The role of Lanspec AEDS in high-purity turbine
Written by: Sean Hodgkinson, Sales Director
Turbine blade fouling is one of the most persistent and costly challenges in power generation, aviation, offshore and heavy industry. Over time, airborne contaminants, lubricating oils, combustion by-products, dust and salt deposits accumulate on compressor and turbine surfaces, degrading aerodynamic efficiency and driving up fuel consumption. Regular, high-quality cleaning is therefore essential to protect performance, minimise downtime and extend the working life of extremely expensive components.
But cleaning a turbine blade is not simply about removing dirt. What you leave behind matters just as much as what you take away — and this is where the purity of your surfactant becomes critical. This article looks at why Lanspec AEDS, a highly purified, de-ionised nonionic surfactant, is uniquely suited to turbine blade cleaning.
Why Clean Turbine Blades?
Even a thin layer of contamination can significantly disrupt airflow across blade surfaces. Typical deposits include:
• Hydrocarbon oils and greases
• Carbonaceous and combustion residues
• Atmospheric dust and particulates
• Salt contamination (particularly in marine and offshore environments)
• Industrial pollutants and process-derived organic deposits
Left unchecked, these deposits lead to reduced compressor efficiency, increased fuel consumption, higher operating temperatures, reduced power output and rising maintenance costs.
The Role of Lanspec AEDS
Lanspec AEDS is a highly purified, de-ionised alcohol ethoxylate surfactant developed for demanding industrial cleaning formulations. It combines strong detergency with a low-foam profile, making it ideal for both immersion and recirculating wash systems.
✓ Excellent wetting and rapid soil penetration
✓ Strong detergency towards hydrocarbon and oily deposits
✓ Low foam — ideal for recirculating and spray systems
✓ Easy rinsing with minimal residue
✓ Effective across a broad temperature range
✓ Very low free metal ion content (see below)
Why Free Sodium and Potassium Matter — The Hot Spot Problem
The single most important reason to specify de-ionised Lanspec AEDS for turbine blade cleaning is its very low residual free metal ion content — specifically sodium (Na⁺) and potassium (K⁺).
Conventional base-catalysed alcohol ethoxylates carry residual alkali metals left over from the manufacturing catalyst. If a surfactant containing these ions is used to clean turbine blades, and any trace residue remains after rinsing, those metals become a serious liability at operating temperature.
How Sodium and Potassium Cause Hot Spots
Turbine blades operate at extremely high temperatures. When sodium and potassium salts are deposited on the blade surface, they can:
• Form low-melting-point molten salt films on the metal surface
• Combine with sulphur (from fuel or air) to create sodium and potassium sulphates
• Break down the protective oxide layer on the blade alloy
• Initiate hot corrosion (sulphidation attack)
• Create localised hot spots where heat is no longer evenly dissipated These hot spots accelerate localised metal degradation, cause uneven thermal stress, promote pitting and cracking, reduce component life and can ultimately lead to catastrophic blade failure. In gas turbines in particular, sodium and potassium are recognised as primary drivers of Type I and Type II hot corrosion — among the most damaging and costly degradation mechanisms in turbine engineering.
The AEDS Advantage
Because Lanspec AEDS is de-ionised to remove residual sodium and potassium, it allows formulators to build powerful cleaning products without introducing the very contaminants that cause hot corrosion.
✓ Ultra-low free metal ion content
✓ Minimal risk of alkali metal residue on blades
✓ Reduced potential for hot corrosion and sulphidation
✓ Protection against localised hot spot formation
✓ Cleaner, safer, longer-lasting turbine components
In short: using a standard surfactant to clean a turbine blade can leave behind the exact ions that later destroy it. Using de-ionised Lanspec AEDS removes that risk at source.
Lanspec AEDS — Free Metal Ion Specification
Lanspec AEDS is manufactured and quality-controlled to a tightly defined free metal ion specification, verified batch by batch:
Parameter | Specification | Test Method |
Metals as Sodium (Na) | 20 ppm max | LL4075 |
Metals as Potassium (K) | 20 ppm max | LL4675 |
Appearance at 25°C | Clear colourless to pale yellow liquid | LL1000 |
Both sodium and potassium are controlled to a maximum of 20 ppm, ensuring an exceptionally low free metal ion load in the finished surfactant.
Guide Formulations
The following starting-point formulations demonstrate how Lanspec AEDS can be built into turbine and compressor cleaning products. All are guide formulations and should be validated for the specific application, substrate and operating conditions.
Formulation 1 — Turbine Compressor Wash Concentrate
Raw Material | % w/w |
Lanspec AEDS | 8.0 |
Sodium Citrate | 2.0 |
Sodium Gluconate | 2.0 |
Isopropyl Alcohol (IPA) | 5.0 |
De-ionised Water | 83.0 |
Total | 100.0 |
Low foam, excellent oil removal, dilute 1:5 to 1:20 in use, good corrosion profile.
Formulation 2 — Heavy Duty Turbine Cleane
Raw Material | % w/w |
Lanspec AEDS | 6.0 |
Potassium Carbonate | 4.0 |
Sodium Gluconate | 3.0 |
Butyl Diglycol | 5.0 |
De-ionised Water | 82.0 |
Total | 100.0 |
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Enhanced removal of baked-on hydrocarbon deposits; suited to offline cleaning with good metal compatibility.
Formulation 3 — Aviation Compressor Cleaner
Raw Material | % w/w |
Lanspec AEDS | 5.0 |
Isopropyl Alcohol (IPA) | 10.0 |
Corrosion Inhibitor Package | 1.0 |
De-ionised Water | 84.0 |
Total | 100.0 |
Ideal for routine maintenance washing, online compressor cleaning, recirculation systems and spray application.
Formulation 4 — Low Foam Turbine Maintenance Cleaner
Raw Material | % w/w |
Lanspec AEDS | 4.0 |
Sodium Gluconate | 2.0 |
EDTA Solution (40%) | 2.0 |
De-ionised Water | 92.0 |
Total | 100.0 |
Ideal for routine maintenance washing, online compressor cleaning, recirculation systems and spray application.
Specific Application Examples
1. Online Gas Turbine Compressor Washing
Injected into the compressor inlet while the unit is running (or on crank), a dilute Lanspec AEDS wash lifts oily and particulate fouling from the early compressor stages. Its low-foam behaviour prevents foam carry-over, and its ultra-low sodium and potassium content ensures no corrosive salts are introduced into the hot gas path — a critical requirement for online washing.
2. Offline Gas Turbine Crank Washing For heavier fouling, the turbine is washed offline on crank with a more concentrated formulation (e.g. Formulation 2). AEDS penetrates baked-on hydrocarbon and carbonaceous deposits, restoring blade profile and compressor efficiency, followed by a thorough de-ionised water rinse.
3. Aero-Engine Compressor Cleaning
In aviation MRO, blade cleanliness and residue control are paramount. The fast-drying, low-residue Formulation 3 removes operational fouling from aluminium and alloy compressor components while the low free metal ion profile of AEDS avoids leaving chloride- or alkali-metal residues that could initiate corrosion in service.
4. Steam Turbine Blade Cleaning During Overhaul
During shutdown and overhaul, steam turbine blades are cleaned to remove deposits and hydrocarbon films before inspection. AEDS-based cleaners provide effective detergency with easy rinsing, leaving surfaces clean and residue-free for non-destructive testing.
5. Offshore and Marine Turbine Maintenance
In salt-laden marine environments, removing sodium and potassium salt deposits — without adding more — is essential. The high-purity AEDS platform is particularly valuable here, cleaning effectively while keeping the free metal ion contribution of the cleaner itself to an absolute minimum.
Technical Considerations
Typical use level of Lanspec AEDS: 0.5–3.0% active in use
Cleaning temperature: 20–60°C
Contact time: 5–30 minutes deending on fouling
Always follow with a thorough water rinse
Use demineralised / de-ionised water where salt residues are critical
Conclusion
Maintaining clean turbine blades is one of the most cost-effective ways to preserve efficiency and reduce operating costs. But in high-temperature turbine environments, purity is performance. Through its combination of low-foam detergency, excellent wetting and — crucially — ultra-low free metal ion content, Lanspec AEDS offers formulators a versatile, high-purity surfactant platform for modern turbine cleaning products.
By combining low-foam detergency with ultra-low free metal ion content, Lanspec AEDS doesn’t just clean turbine blades — it helps protect them from the sodium- and potassium-driven hot corrosion that shortens blade life.
To discuss turbine cleaning formulations or request a sample of Lanspec AEDS, contact the Lankem technical team at technical@lankem.com.
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