Case Study – Critical Lubricants: Oil Degradation Invisible to Standard Analyses

European Refinery – Turbine & Compressors

Advanced diagnostics (APH membranes / ESR) and Antara solution (AUGEO OIL + TRO Dual system – oil regeneration )

Context & Objectives

Operator: Large European refinery operating a turbine and two critical process gas compressors.

Issue: ISO code drift from 17/16/15 to 20/17/15, initially misinterpreted as particulate contamination.

Internal analyses: MPC = 8, parameters considered acceptable → initial recommendation for a full oil-system flushing.

Objectives: Identify the real root cause, characterize lubricant degradation by-products, avoid a heavy flushing, and leverage a reusable case study for other units.

Advanced diagnostics – resins, radicals, trace copper

Membrane analyses

MPC vs APH membranes: revealing polar degradation products

MPC = 8 → deemed satisfactory.
APH membranes (0.8 µm, more polar) → strong retention of degradation products.
Brown–orange, crystalline & gel-like deposits on the APH membrane.
Resins and polar compounds underestimated by standard MPC evaluation.

ESR / ICP analysis

Aminyl radicals & copper complexes

Aminyl radicals: advanced degradation of amine antioxidants.
Copper complex detected by ESR but not visible by ICP (ppb-level presence).
Confirmation of a copper alloy in the circuit, acting as a catalyst for radical reactions.

The ISO drift is not caused by hard particles but by an active chemical degradation of the lubricant (resins, polar compounds, radicals), catalyzed by trace copper. Standard analyses (MPC, ICP) alone do not fully capture this phenomenon.

Antara solutions – clean, stabilize, regenerate

Curative phase

AUGEO OIL – targeted cleaning

Solubilization of polar degradation products and resins responsible for deposits.
Cleaning internal deposits in the turbine and compressors.
Neutralization of the most reactive degradation species.

This curative phase restores a clean and stable baseline before implementing continuous regeneration with TRO systems.

Permanent phase

Continuous regeneration with the TRO Dual system

Continuous removal of polar degradation products and their precursors.
Reduction of radicals that accelerate oil oxidation.
Limitation of catalytic effects from trace copper species.
Long-term stabilization of the lubricant and its antioxidant package.

The operator shifts from one-off treatments to a proactive oil health management, leveraging the Antara TRO Dual system .

Expected results

Drastic reduction of resinous and gel-like deposits in the oil system.
Long-term stabilization of the antioxidant package and lubricant chemistry.
Improved ISO cleanliness without performing a full flushing.
Extended oil lifetime and reduced consumption.
Increased availability of critical turbines and compressors.

Benefits for the operator

Fewer unplanned stops linked to lubrication issues.
Stabilized operational performance on critical equipment.
Secured operational continuity, independent of supply chain disruptions.

Benefits for maintenance & reliability

Full flushing avoided (time, budget, and risk savings).
Reduced corrective interventions on the oil system.
Team capability upgrade through advanced diagnostics (APH membranes, ESR).

This case study is based on an intervention carried out for a large anonymous European refinery operating critical equipment. Antara Groupe combined advanced diagnostics – APH membranes, ESR analysis, and interpretation correlated with operational data – to reveal a complex chemical degradation of the lubricant invisible to standard analyses alone.

The combined approach AUGEO OIL + TRO Dual system addressed the true root cause (polar compounds, resins, radicals, copper catalysis) without requiring a full flushing. This methodology illustrates Antara’s ability to support sensitive installations, secure long-term oil health, and deploy a sustainable strategy applicable to similar units.

Applicable to turbines, compressors, hydraulic systems and critical oil circuits.