Diethylene Glycol in Gas Turbines and Jet Fuels: An Anti-Icing Additive

In the world of aviation and power generation, where performance meets precision, even the smallest detail can make a big difference. One such detail is water — not the kind you drink, but the invisible moisture that sneaks into jet fuels and gas turbine systems like a stealthy saboteur. Left unchecked, this moisture can freeze at high altitudes or cold operating conditions, clogging filters, damaging engines, and potentially grounding flights or shutting down power plants.

Enter Diethylene Glycol (DEG) — a humble yet powerful compound that has found its niche as an anti-icing additive in both jet fuels and gas turbines. In this article, we’ll explore why DEG has earned its place in these critical systems, how it works, and what makes it a preferred choice among various alternatives.

A Cold Welcome: The Problem with Ice in Fuel Systems

Imagine flying at 35,000 feet on a commercial airliner. The outside temperature hovers around -40°C, and the fuel inside the tanks is just as cold. Any trace of water in the fuel — which is inevitable due to condensation, humidity, or contamination — can crystallize into ice particles. These tiny crystals may seem harmless, but they can wreak havoc by:

Blocking fuel filters and strainers
Damaging engine components through abrasion
Disrupting fuel flow, leading to engine flameout

In ground-based gas turbines used for power generation, similar issues arise during cold weather operations. Moisture-laden fuels can cause icing in fuel lines, injectors, and combustion chambers — especially when the ambient temperature drops below freezing.

To combat this, anti-icing additives are introduced into the fuel system. Their role? To either prevent ice formation or inhibit the agglomeration of ice crystals so they don’t clump together and block anything important.

Diethylene Glycol: From Humble Origins to High-Flying Applications

Diethylene glycol is a colorless, odorless, hygroscopic liquid with the chemical formula C₄H₁₀O₃. It’s a member of the glycol family, closely related to ethylene glycol and triethylene glycol, and is commonly used in industrial applications ranging from antifreeze to natural gas dehydration.

Physical and Chemical Properties of DEG

Property	Value
Molecular Weight	106.12 g/mol
Boiling Point	245°C
Melting Point	-10.45°C
Density	1.118 g/cm³ at 20°C
Viscosity	16.1 mPa·s at 20°C
Solubility in Water	Miscible
Flash Point	167°C

DEG’s ability to absorb and retain water (hygroscopic nature) makes it particularly effective in fuel systems where moisture control is essential. But how exactly does it prevent ice formation?

Mechanism of Action: How DEG Fights Ice

The key lies in DEG’s interaction with water molecules. Here’s how it works:

Water Absorption: DEG attracts and binds with free water molecules present in the fuel.
Lowering Freezing Point: By forming hydrogen bonds with water, DEG disrupts the orderly arrangement required for ice crystal formation.
Crystal Modification: Even if some ice forms, DEG prevents the crystals from growing large enough to cause blockages.

This dual-action mechanism — absorbing moisture and modifying ice behavior — makes DEG a versatile tool in both aviation and power generation.

But DEG isn’t the only player in the game. Other anti-icing additives include methanol, glycerol, and triethylene glycol (TEG). Each has its pros and cons, but DEG strikes a balance between efficiency, cost, and compatibility with existing fuel systems.

DEG in Aviation: Keeping Jets Icy-Free

Jet fuel, specifically Jet A and Jet A-1, must meet stringent standards set by organizations like ASTM International and the UK Ministry of Defence. One such standard is the ASTM D3429 test method for evaluating anti-icing additives in aviation fuels.

Application in Commercial Aviation

In commercial aircraft, DEG is typically added at concentrations ranging from 0.1% to 0.3% by volume, depending on environmental conditions and operational requirements. This dosage is sufficient to manage typical moisture levels without affecting fuel performance or engine operation.

Advantages of Using DEG in Jet Fuel

Low Toxicity: Compared to methanol, DEG poses fewer health risks during handling.
High Efficiency: Effective at low concentrations.
Fuel Compatibility: Does not react adversely with hydrocarbon fuels.
Cost-Effective: More economical than some synthetic alternatives.

A study published in the Journal of Aerospace Engineering (Smith et al., 2016) compared several anti-icing agents and concluded that DEG offered the best balance between performance and safety for use in commercial aviation.

DEG in Gas Turbines: Power Without the Freeze

Gas turbines, whether used in power plants or industrial settings, also face icing issues, especially when using natural gas or distillate fuels in cold climates. DEG finds application here primarily in two ways:

Fuel Dehydration: Removing water vapor from incoming fuel streams.
Anti-Icing Protection: Preventing ice buildup in fuel lines and injectors.

Typical Dosage in Gas Turbine Applications

Application	Recommended Concentration
Natural Gas Dehydration	5–10 wt%
Distillate Fuel Treatment	0.2–0.5 vol%

While higher concentrations are used in gas dehydration, lower doses suffice for anti-icing purposes. The exact amount depends on ambient temperature, humidity, and fuel type.

Benefits in Gas Turbine Operations

Improved Reliability: Reduces downtime due to ice-related failures.
Extended Equipment Life: Minimizes wear caused by abrasive ice particles.
Operational Flexibility: Enables reliable performance in sub-zero environments.

According to a technical bulletin from General Electric (GE Energy, 2019), DEG-based treatments were shown to reduce filter plugging incidents by over 60% in winter operations across northern Europe.

Safety and Environmental Considerations

Despite its usefulness, DEG is not without drawbacks. While less toxic than ethylene glycol, it still poses health risks if ingested or inhaled in large quantities. Therefore, proper handling protocols must be followed.

From an environmental perspective, DEG is biodegradable under aerobic conditions, though its breakdown products can impact aquatic life if released in large amounts. Most regulatory bodies classify DEG as non-hazardous for transport under normal conditions.

Comparative Analysis: DEG vs. Other Anti-Icing Agents

Additive	Effectiveness	Cost	Toxicity	Fuel Compatibility	Ease of Handling
Diethylene Glycol (DEG)	★★★★☆	★★★☆☆	★★★★☆	★★★★★	★★★★☆
Methanol	★★★★☆	★★★☆☆	★★☆☆☆	★★★☆☆	★★★☆☆
Triethylene Glycol (TEG)	★★★★☆	★★☆☆☆	★★★★☆	★★★★☆	★★★☆☆
Glycerol	★★★☆☆	★★★★☆	★★★★★	★★★☆☆	★★★★☆

As shown above, DEG holds a strong position across most categories, making it a popular choice in many industries.

Regulatory Standards and Industry Acceptance

DEG’s use in aviation and gas turbines is governed by several international standards:

ASTM D3429: Standard Test Method for Anti-Icing Additives in Aviation Fuels
DEF STAN 91-091: UK military specification for Jet A-1 fuel
ISO 1817: International standard for testing glycols in fuel systems

Many major airlines and power companies have adopted DEG-based formulations as part of their standard operating procedures, further cementing its reputation.

Future Outlook and Emerging Trends

With climate change leading to more extreme weather patterns, the need for effective anti-icing solutions is likely to grow. Researchers are exploring ways to enhance DEG’s performance through:

Nano-additives: Combining DEG with nanoparticles to improve ice-crystal dispersion
Bio-based Alternatives: Developing greener versions of glycols with similar properties
Smart Delivery Systems: Controlled-release mechanisms for optimal dosing

One promising development comes from a joint study by MIT and Rolls-Royce (Zhang et al., 2022), which tested a DEG-polymer hybrid additive capable of reducing ice nucleation by up to 80% under simulated flight conditions.

Conclusion: A Little Glycol Goes a Long Way

In the grand scheme of things, diethylene glycol might seem like a minor ingredient in the vast machinery of aviation and energy production. Yet, its role is nothing short of critical. From preventing catastrophic engine failures to ensuring uninterrupted power supply in icy conditions, DEG quietly keeps the wheels — and turbines — turning.

So next time you board a plane or flick on a light switch in the middle of winter, take a moment to appreciate the invisible workhorse working behind the scenes: diethylene glycol, the unsung hero of anti-icing technology.

References

Smith, J., & Patel, R. (2016). Evaluation of Anti-Icing Additives in Jet Fuels. Journal of Aerospace Engineering, 29(3), 45–58.
GE Energy. (2019). Gas Turbine Fuel System Maintenance Guide. Technical Bulletin No. TGB-2019-04.
Zhang, L., Wang, Y., & Kumar, S. (2022). Advanced Glycol-Based Additives for Ice Prevention in Aerospace Fuels. MIT-AER Report No. 22-07.
ASTM International. (2020). Standard Test Method for Anti-Icing Additives in Aviation Fuels (ASTM D3429).
DEF STAN 91-091. (2018). Aviation Kerosene Requirements.
ISO 1817:2022. Petroleum Products – Determination of Anti-Icing Additives in Fuels.

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