Widespread recent flooding in Queensland and other Southern Hemisphere regions has left many communities devastated and caused serious disruptions to industrial activities such as mining.
In Australia, for example, flooding has affected the Queensland coal industry, not only causing producers to lose an estimated billion dollars in lost production, but also costing them many hundreds of millions to repair machinery and infrastructure inundated by water.
Dingo Maintenance Systems, a supplier of mine-maintenance software solutions based on CBM and oil analysis principles, recently issued a technical bulletin outlining the types of damage to look for and the maintenance response needed to cope with water-damaged equipment.
According to the Dingo bulletin:
- Equipment that may have been fully submerged will require a full recovery effort, including a flush of all systems: Make sure provisions are in place to document and track conditions of each asset/component for any potential warranty/insurance payable issues, as well as to accurately monitor conditions going forward.
- Do a thorough examination of bulk oil storage facilities: If contaminated, oil should be removed, tanks flushed and corrective actions taken. Do not place new oils into an already contaminated source. Ensure that cleanliness of newly arriving bulk oil is at acceptable levels as flooding may also have affected vendors as well. Do visual checks of oil condition and perform onsite testing if possible. Sample all oils and fuels and expedite samples to your testing labs.
- Establish a Mission Criticality and Priority List of which equipment must be addressed first: This may require that all engines have oil/filter changes once bulk oil supplies are determined to be usable. Ensure that oil samples are taken after drain so necessary condition monitoring can move forward. Other component oils may be able to wait until a later date; this should be a case by case basis. Closely monitor the results of the next series of oil samples as there can be residual contamination.
- Ensure that the warehouse facility has adequate inventory of filters and breathers: Using contaminated, old or improper inventory can be just as destructive as not doing anything at all.
- Visually asses each location affected to determine specific issues and steps for corrective actions. All affected sites should understand that conducting a proper assessment will, to a large degree, determine the time frame in which sites can be back to full operation and production.
- Maintain clean work shop facilities: Ensure that additional contamination does not result from muddy work environments. Wash equipment thoroughly,if possible, to facilitate inspection and leak identification.
- Be vigilant in OEM oil/filter change intervals: Depending on asset/mission criticality, consider falling back to one-half normal intervals until conditions determine otherwise. This is also important for kidney loop filtration on components which were previously serviced in this way and not solely on a condition-based schedule.
- Aggressively monitor fuel sources, as water, algae and assorted microbials will be present: These conditions will plug filters both in delivery applications and in-service equipment. Biological growth bacteria, fungi or mold is likely due to the presence of water in the fuel. For locations that use biodiesel, this fuel has a typical shelf life of around six months—but that can be reduced by many factors/variables.
- The effects of water contamination can be wide-ranging, including:
- Shorter component life due to rust and corrosion: Water attacks iron and steel surfaces to produce iron oxides. Water teams up with acid in the oil and will corrode ferrous and nonferrous metals alike. Rust particles are abrasive and get ground up in the system where the associated metallurgical wear elements can serve as a catalyst that increases the process at an exponential rate. Abrasion exposes fresh metal which corrodes more easily in the presence of even lower concentrations of water and acid.
- Water etching/erosion and vaporous cavitation: Water etching can occur on bearing surfaces and raceways, primarily caused by generation of hydrogen sulphide and sulphuric acid from water-induced lubricant degradation with vaporous cavitation.
- If the vapor pressure of water is reached in the lowpressure regions of a machine, such as the suction line of a pump or the pre-load region of a journal bearing, the vapor bubbles expand. Should the vapor bubbles be subsequently exposed to sudden high pressure, such as in a pump or the load zone of a journal bearing, the water vapor bubbles quickly implode and simultaneously condense back to the liquid phase. The water droplet impacts a small area of the machines surface with significant force in the form of a needle-like micro-jet, which causes localized surface fatigue and erosion.
- Water contamination also increases oil’s ability to entrain air, thus increasing gaseous cavitation.
- Hydrogen embrittlement: Hydrogen embrittlement occurs when water invades microscopic cracks in metal surfaces. Under extreme pressure, water decomposes into its components and releases hydrogen. This explosive force causes the cracks to become wider and deeper, leading to spalling.
- Oxidation of bearing babbitt material
- Wear caused by loss of oil film or hard water deposits: Rolling element bearings and the pitch line of a gear tooth are protected because oil viscosity increases as pressure increases. Water does not possess this property. Its viscosity remains constant (or drops slightly) as pressure increases. As a result, water contamination increases the likelihood of contact fatigue (spalling failure).
- Be aware of the effects of water on lubricating oil:
- Accelerates oxidation of the oil
- Depletes oxidation inhibitors and demulsifiers
- May cause some additives to precipitate
- Causes ZDDP antiwear additive to destabilize over 180°F
- Competes with polar additives for metal surfaces.
