Ionic Liquid Lubricant Coking Resistance
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Solution Overview
Problem
Current lubricating compositions for high-temperature applications, such as aircraft turbines and conveyor chains, face challenges with thin-layer coking, which leads to performance degradation and equipment failure due to insufficient resistance to thermal oxidation and coking, despite advancements in thermal stability and anti-wear properties.
Innovation Solution
A lubricating composition comprising 20% to 100% of a specific mixture of ionic liquids with sulfonylimide anions and nitrogen heterocycle or quaternary ammonium cations, selected for their high start of deposition temperature in thin layers, exceeding 330°C, as determined by the Micro Coking Test (MCT) method, to enhance thermal stability and resistance to coking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional lubricants (mineral or synthetic esters) are used in high-temperature applications, then lubrication is provided, but thermal stability and resistance to coking are insufficient leading to coke formation
Solution Approach 1:
The patent changes the chemical composition parameters of the lubricant by using ionic liquids with specific cation-anion combinations (e.g., imidazolium with bis(trifluoromethylsulfonyl)imide anion) that inherently resist coking at high temperatures, replacing traditional ester-based lubricants that decompose and form coke
Solution Approach 2:
The patent employs composite ionic liquid formulations combining specific cations and anions to create a lubricating composition that maintains thermal stability and prevents coke formation, leveraging the synergistic properties of the ionic liquid components
2Productivity
If air inlet temperature of turbines is increased to improve efficiency, then fuel consumption and emissions are reduced, but temperature of lubricating composition in turbine bearings increases leading to accelerated coking
Solution Approach 1:
The patent modifies the thermal stability parameters of the lubricant by selecting ionic liquids with decomposition temperatures exceeding 330°C (as measured by MCT), enabling the lubricant to withstand the elevated temperatures resulting from higher turbine operating temperatures
3Reliability
If conventional additives (antioxidants, anti-coking agents) are added to traditional lubricants, then some protection is provided, but the lubricants still reach limits of thermal stability and form gums that cok over time
Solution Approach 1:
The patent fundamentally changes the base lubricant chemistry from traditional esters to ionic liquids, which possess inherent thermal stability and resistance to oxidation without requiring conventional additives, thereby extending service life before coking occurs
Solution Approach 2:
The patent replaces complex additive packages in traditional lubricants with a simpler, more stable ionic liquid base that provides long-term protection without degradation, reducing the need for frequent maintenance and replacement
Data Source
Figure 1~3
AI summary
The present invention relates to a lubrication method that includes a step of lubricating a machine with a lubricating composition comprising one or more ionic liquids comprising at least: an anion selected among the sulfonylimides of which the one or more substituents are independently selected among a fluoroalkyl, fluoroether, perfluorinated alkyl or perfluoroether group; and a cation comprising a nitrogen-containing heterocycle or a quaternary ammonium, of which the one or more substituents are independently chosen among: hydrogen or the alkyl, alkoxy, fluorinated alkyl, perfluorinated alkyl, silane alkyl, alkyl alcohol, vinyl, alkyl allyl, ether or polyether groups having a straight or branched chain having 1 to 3 carbon atoms, with the condition that when the cation is a quaternary ammonium, at least two of these substituents are a methyl group, the one or more ionic liquids having a thin-film deposition starting temperature (MCT method) which is at least equal to 330°C, and making it possible to reduce the deposits formed in said machine.