- Easily used by ships maintenance staff right out of the box
- Instant indication of condition for motor bearings, gears, compressors, slewing rings, hoists, winches...
- Plan maintenance and have the spares available on time. Minimise off-hire and demurrage.
Infrared IR FTIR Oil Analysis
FTIR (FT, an acronym for Fourier Transforms) is the predominant IR methodology in oil analysis because FT provides mathematical calculations at extremely high speeds, enabling this type of analysis to be relatively quick and inexpensive, with an impressive yield of information.
Test Description: Infrared Analysis is a form of spectroscopy that relies on energy absorption within the infrared (IR) spectrum, as opposed to ultra-violet absorption (or emission) for metals. IR detects and quantifies molecular structures of interest whose absorption frequencies are unique. The process is much the same as for UV-SM, except that one is investigating, specific types of organic molecules or molecular partials whose atomic bonding chemistry ‘resonates’ or vibrates at its signature frequency(s). The amount of radiation absorbed is proportional to the concentration of the molecular structure that resonates at the inspection frequency.
These molecular components of interest are often called “functional organic groups”. These groups, in turn, belong to specific types of chemicals and compounds, such as water, glycol, numbers of oil and fuel additives, oxidation-nitration-sulphation (degradation) indicators, and much more. IR can also render a ‘diesel fuel soot’ concentration reading. This particular measurement is accomplished by availing a different phenomenon within the IR technique, known as ‘light scattering’ (aka Tyndall Effect), and such dispersion is proportional to soot particulates concentrations.
Reporting Units: Standard for IR reporting, with the exception of ‘soot’ (reported in per cent), is usually AU (Absorbance Units, a scalar value), however newer additions to IR’s arsenal of capabilities, such as direct determination of AN (Acid Number, formerly TAN) or BN (Base Number, formerly TBN), are usually reported in their industry-standard, quantitative reporting units for those particular inspections.
Lubricant manufacturers have been slow to respond to AUs, though some now publish guidelines. It is very important to understand that a New Lube Reference must be analyzed as a baseline in order to achieve credible results, particularly true with synthetic lubes, which tend to have a high oxidation-nitration-water ‘floor’.
Following are common typical measurements availed via FTIR:
- Oxidation – Chemical inclusion of oxygen within the lube’s base stock molecules. Oxidation causes a varnish and deposit precursor that greatly reduces oil lubricity (slipperiness and friction-reducing functionality). It self-propagates with increasing concentrations and usually promotes or causes adverse oil thickening. Oxidation often the result of excessive lube temperatures and/or aeration in the oil sump
- Nitration – Chemical inclusion of nitrogen within the lube’s base stock molecules. Nitration also causes a varnish and deposit precursor that greatly reduces oil lubricity. Excesses often indicate timing or fuel mixture issues in internal combustion engines, particularly in natural gas- and propane-fuelled systems
- Sulphation – Sulphur compounds formed as by-products of diesel fuel combustion. Lower boiling fuels, such as #1 or #2 diesel fuel, will contain a degree of sulphur, however, the sulphur content in transportation fuels used in developed countries has been reduced to nil, minimizing sulphation effects in the lube where such fuels are used. “Heavier” fuels, such as Residual diesel, are routinely in use for deep draft marine propulsion engines. Here sulphur content can be considerable and sulphation will be readily observed. Not surprisingly such fuel systems require a lubricant with a high alkaline reserve (Base Number / BN) to neutralize high amounts of sulphuric acid that form under such circumstances
- Additive Depletion, including BN – Certain additives can be tracked as to functional effectiveness and, recently, a method for BN determination via IR analysis was developed
- Water – most any amount of water can be devastating to a lube system, with effects such as additive hydrolysis, a destructive, irreversible chemical process that compromises beneficial effects, rust and corrosion
- Soot agglomeration and subsequent deposition
- Glycol – from cooling system egress to the oil sump - sufficient amounts may cause bearing or piston seizures
- Fuel Soot (diesels) – Excessive amounts may indicate: Timing issues, Over-fuelling or dribbling injectors, Worn compression rings
- AN (Acid Number, formerly TAN) can represent lube oxidation
- BN (formerly TBN) deficiency, possible corrosion occurring
- Fuel Dilution* (limited to relatively high amounts) – Fuel dilution is raw fuel residing in the crankcase. Causes can include: Leaking injector seals or jumper lines, leaking fuel pump (internal mount), excessive idling, allowing unburned fuel to escape past compression rings. Note : Gas chromatography is the preferred fuel dilution method, with surface wave acoustics and steam distillation also viable
* FTIR is at a relative handicap as a fuel dilution technique because fuel oils and hydrocarbon lubricating oils resemble each other in the chemical sense, thus FTIR has the bittersweet property of being generally limited, but specifically quite capable. If one has valid samples of the fuel from the same supply source, proper referencing can be set up, but if not, the determination will be tenuous, i.e., FTIR is usually not the best approach to fuel contamination determination/measurement.
Additional IR Notes: IR / FTIR is still a frontier in oil analysis and one can expect numbers of additions to its capabilities. As well, IR analyzers of high quality have become trans-portable, even hand-held in some instances, allowing On-Site testing to be substantially fortified in the infancy of 21st century CM.