The greatest problems in waste oil in egypt
Water will affect the oil’s base stock, encouraging oxidation, viscosity increase and foaming.
Water can also affect the additive package through Water washing and hydrolysis, leading to acids and additive depletion.
Water encourages rust and corrosion and will cause increased wear as a result of aeration, changes in viscosity resulting in film strength failure, hydrogen blistering and embrittlement, and vaporous cavitation.
Finally, Water is a generator of other contaminants in the oil such as waxes, suspensions, carbon and oxide insolubles and even micro-organisms.
The following technologies applied to remove Water from oil, in Egypt
As already mentioned, free Water in the system will settle to the bottom of the tank (assuming the specific gravity of Water is greater than the lubricant).
In basic systems, opening the drain valve and allowing the Water to drain off may be sufficient.
The effectiveness of this action, however, will depend upon how long the system was allowed to stand prior to draining the water, whether the temperature was low enough to lower the saturation point dramatically and the oil’s demulsibility characteristics. Lowering the saturation point helps ensure that as much of the Water as possible will exist in the free state. tank may be employed to allow the oil to cool
The major downside to this method is that it removes only free water, so elements of emulsified and dissolved Water will remain.
The upside is the low cost of Water removal.
Centrifuge - Spin Your Oil Clean
The principle of the centrifuge is to separate the oil’s heavier elements by spinning the oil to create high G-forces - often in the tens of thousands of Gs.
The greater the difference in specific gravity between the contaminant and the oil, the more effective the process.
For this reason, centrifuges often work better on low specific gravity and low viscosity oils, like turbine oils, rather than heavier gear type oils.
In a centrifuge, both free and emulsified Water will be removed; this will depend to some extent on the type of additive package, as some Water will be held in suspension in the oil.
Typically, most filter media will absorb a small amount of moisture from the oil, resulting in swelling of the media.
This is particularly true for cellulose-based media. In fact, examination of used filters will often indicate if the presence of Water is a concern.
Some filter cartridges with an additional wrap consisting of polymer and desiccants are available.
These filters are specifically designed to remove Water by absorption and remove both emulsified and free water, as well as solids.
However, the elements typically have a limited volume capacity and are best fitted to a portable filter cart for minor Water ingression problems.
Vacuum the Oil Dry
The vacuum dehydration process lowers the partial pressure, which assists in removing the Water from the oil.
Just like boiling Water on top of Mount Everest, lowering the pressure allows Water (and other volatile materials) to boil at a much lower pressure.
At the typical pressures used by most vacuum dehydrators (25" to 28" of mercury), Water boils at 120°F to 130°F.
By heating the oil, typically to 150°F to 160°F, Water is vaporized inside the dehydrator, without causing excessive oil degradation due to thermal and oxidative stress.
In most dehydrators, the air is warmed and dried prior to being passed over the oil, encouraging the Water to transfer from the oil into the air.
To maximize the process, the oil is thinned to obtain the greatest amount of surface area exposure possible.
This is achieved by allowing the oil to pass over a number of surfaces internally in the vacuum chamber, or by creating an umbrella spray within the chamber through which the dry air passes.
Dehydration by Air Stripping
An alternative technology to vacuum dehydration is dehydration by air stripping a process that removes Water as well as gaseous contaminants in the oil.
Not only does it remove free and emulsified water, but also dissolved Water down to less than 100 ppm.
Because of its ability to degas, it is also suitable for removing hydrocarbons in seal oil systems.
Air stripping works by drawing air or nitrogen gas into a stream of heated oil, which mixes in and absorbs the Water and gasses within the oil.
The oil/air is then expanded to release the air or nitrogen, which takes the impurities with it.
The exhaust air and gasses are also controlled to minimize the oil vapor released.
Heat the Oil Dry
Some applications are self-cleansing because they run at elevated temperatures and consequently, Water is evaporated.
The combustion engine is a perfect practice to deliberately heat the oil briefly to drive off moisture to maintain oil health is open to debate.
Allowing the Water to remain in the oil is usually far more damaging than briefly heating the oil.
And in static systems, like reservoirs, ensure that the power density of such elements remains below 5W/in2 to minimize thermal stress to the oil.
The downside to heating oil is that it must be controlled, particularly with mineral oils, to avoid harm. However, the relative cost is less than the centrifugal or vacuum separation technologies, making this an effective Water removing tool in certain circumstances.