The lubricants industry is acutely aware of the need for environmentally-conscious options and sustainable development choices. In response to this demand, biolubricants began to make their mark a few years back. The term biolubricants applies to all lubricants that biodegrade expediently and which are non-toxic for both human beings and aquatic habitats. They may be plant-oil based (such as rapeseed oil derived) or synthetic esters manufactured from modified renewal oils.
Biolubricants are the preferred choice for all applications which may pose risks to the environment such as lost oils (chainsaw chain oils, two-stroke engine oils, formwork release agents and greases.) as well as oils that may inadvertently leak (such as hydraulic oils, oils for engines, gearboxes, axles, etc.). Employing biolubricants is especially encouraged when environmental protection is an ongoing concern; for instance, in aquatic, mountain, agricultural and forest environments or deep quarries.
Water presents a major challenge since it has the highest quantity of oil-related pollution sources. One example is machinery operating in rivers and canals for projects such as dredging or trawling, all devices operating on or near water (such as canal locks and hydroelectric power stations) are also points of concern in this respect.
Other uses of biolubricants include maintaining clean mountainsides. These applications include ski lifts, snow cannons, snowmobiles, snow groomers and other maintenance machinery. These environmentally-sound lubricants are also used to protect the soil in forestry and agriculture equipment in small items such as chainsaws and brush cutters as well as for larger machinery for logging, soil preparation and harvesting. In the unfortunate event of accidental leakage, lost oils and hydraulic and transmission oils can be a source of pollution of the natural forestry or farming environment.
Biolubricants are derived from vegetable and plant oils, which themselves are a variety of non-food biomass energy. Our planet is highly dependent on the use and consumption of fossil fuels (petroleum, coal and natural gas) to fulfil its energy needs. However, our petroleum-based economy may not be sustainable indefinitely; therefore, alternatives need to be explored beyond merely inexpensive, non-renewable fossil-based oils and materials to meet our energy requirements. Biolubricants is the term used mainly to refer to liquid oils derived from renewable or biomass feed stocks. Biolubricants are formed by heating the biomass feedstock in the absence of oxygen, called pyrolysis, or partially combusted in a limited oxygen supply to produce an oil-like liquid. This bio crude oil is further refined into various other biolubricant and bio oil-based products.
It must be noted that there are some technical difficulties to surmount that are associated with this conversion process as the acidic value and water content of the resulting bio crude oil is high, plus energy (possibly fossil fuel energy) has to be consumed in its production. This is in stark contrast to plant and vegetable oils which are composed primarily of different natural oils, fats and acids making them biodegradable and non-toxic. These natural oils sometimes have good lubricity without the need for additional additives and come in a range of viscosities. However, the properties of some kinds of vegetable oils such as low melting points and oxidative stability can limit their use as a biolubricant.
Historically, agricultural land was only used for food production, but today agriculture and farming practices encompass the growing of crops for non-food uses, whether or not they are edible or non-edible products. Such crops include vegetable oils, wax ester oils, plant oils and carbohydrate-based lubricants along with rapeseed, sunflower and olive oils which are all finding industrial applications, with vegetable oils being a significant fountainhead for biolubricant production.
Alternatives to petrol, diesel and other types of fossil fuels have already been put into effect in a number of biomass-based transportation fuels such as biodiesel and bioethanol. Biofuels obtained from sugar cane and oil crops for transportation, which were unimaginable a mere few decades ago, are now becoming a bit more run-of-the-mill, thanks to advanced biofuel pumps being installed in filling stations in certain areas; Consequently, it could be viewed as a natural progression that as well as filling our vehicles with biofuels we should also fill them up with biolubricants.
The replacement of fossil fuels and mineral oils with newer biodegradable lubricant-based oil can aid in substantially diminishing environmental impact and pollution. Vegetable and sunflower oils have been used as a form of lubrication of machinery and the massaging properties of human skin for thousands of years since they have the upper hand over mineral-based oils in being biodegradable and nontoxic. Other types of renewable nontoxic resources include wild plants, biogenetic materials and animal products, residues and wastes that are generated from agricultural and even forestry productions.
Vegetable oils have a large number of other innate positive attributes that imbue them with an advantage over conventional petroleum oils as the feedstock for biolubricants. Some of the qualities of vegetable oils such as excellent biodegradability and low ecotoxicity are of particular importance for oils and lubricants used in environmentally sensitive areas. For example, as stated previously, in river or marine ecosystems, or for those activities in which there is a high potential of the lubricant being lost or spilled in the surrounding environ.
Despite the many advantages of plant-based oil products for biolubricant production, there are challenges which need to be taken into consideration. These include the following:
- Operating temperature limitations
- Low flash point and potential fire hazards
- Quick aging and degradation of bio oils
- Lack of viscosity range
- Poor low temperature fluidity during winter months
- Compatibility with existing oil seat and gasket materials
- Easy formation of sludge resulting in filter clogging and increased maintenance.
Today, market demands and development for biolubricants and transportation fuels has increased environmental compatibility, reduced harmful emissions, improved performance (including longer lifespan and energy efficiency) but most notably, has decreased our dependence on fossil fuel energy. This reinvigorated zeal for vegetable oil as bio-based lubricant has increased exponentially as environmental awareness has grown and become a mainstream concern. The deleterious effects of petroleum oils on environmental and human health are becoming ever more blatant as high performance and economical vegetable oil-based lubricants have been developed and successful marketed. The emphasis on the development of renewable, biodegradable, and environmentally-safe industrial fluids such as biolubricants has led to the expanding use of natural fats and oils for non-edible industrial purposes.
It should be noted that transition to bio-based high-performance lubricants requires keen insight into the interdependence between physiochemical and tribological properties of the bio-based ingredients. Transitioning from a tried and tested mineral oil to an environmentally-acceptable lubricant or EAL will substantially impact the mechanisms relying on the oil performance of journal bearings, transmission gears, thrust bearings, ball bearings, cam followers and, perhaps most dramatically, rubber-made sealing components, these mechanisms are optimized for its use under mineral oils; therefore, new design protocols may be necessary when running together with EALs. This means it is crucial to consider the consequences of using these new ecofriendly lubricants on the entire tribo-system before replacing more traditional mineral oil.
While there are sure to be some growing pains, the current drive toward conservation is sure to continue to propel renewed interest in the use of modified natural oils for non-edible automotive and industrial purposes. The last few decades have resulted in exciting progress towards the use of reliable biodegradable lubes and greases from a variety of renewable sources which promise to keep the world flowing smoothly toward a more ecologically-sound tomorrow.