Biolubricants are products which, when used, have a lower impact on the environment. Biolubricants have a lower impact on aquatic and soil life and cause less health risks. Preferably, they are mainly derived from renewable raw materials, such as rapeseed oil. Their technical performance must at least equal that of conventional lubricants.
In order to meet the technical performance requirements of diverse applications, lubricants contain various components. The source and nature of the base oil and additives do not only influence technical performance, but also the environmental performance of the lubricant. Detailed criteria such as biodegradability, persistence and bioaccumulation, (aquatic) toxicity and other environmental and health hazards, and the extent to which the lubricants are based on renewable materials, determine whether lubricants may be eligible for ecolabels.
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Because of the way in which they are generally used, lubricants often end up in water or soil via loss or leakage loss (see Examples of Oil Pollution). They can be harmful to flora and fauna, especially when they have poor biodegradability. This can affect and diminish the quality of life in and around surface waters. Lubricants used in agriculture or shipping in ecologically sensitive areas are harmful to soil life and aquatic organisms because of the poor biodegradability of mineral oils and the toxicity of certain additives. Ultimately, the quality of drinking water and/or food safety may be at risk.
In the early 1990's, the German working group VDMA 24568 estimated that a maximum of 10% of hydraulic fluids and almost 50% of greases are released into the environment. If these numbers are extrapolated to current figures in Europe, this would come down to ca. 66,000 tonnes of hydraulic fluids and ca. 65,000 tonnes of grease being released into the environment on a yearly basis. Next to engine oil, hydraulic fluids constitute the second largest share of total oil consumption. However, the amount of hydraulic fluids ending up in the environment is equal to the amounts of grease, concrete release agents and chainsaw oil combined. (Krop & Theodori, 2009).
Conventional mineral-based lubricants can pollute surface waters for up to a hundred years. Even small amounts of mineral oil can inhibit the growth of trees. Mineral oil is also toxic to aquatic life forms (even 0.1 ppm of mineral oil reduces the life span of shrimp by as much as 80%).
Biodiversity is better maintained by using non-toxic and readily biodegradable products. The use of renewable materials also reduces a product's carbon dioxide emission. The possible prevention of emissions into the environment by way of maintenance or system adjustments should always be considered.
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Usually, the components of lubricants are divided into base oils and additives. Additionally, lubricating greases contain a certain amount of thickening agents. As a rule of thumb, it can be assumed that biodegradability is determined by the base oils and the toxicity is determined by the additives. The environmental properties of thickening agents tend to vary significantly.
Additives are often sold in packages. In most cases, this means that the package consists of a number of substances that all have their own specific functions. Such a package may, for instance, contain corrosion inhibitors, extreme pressure additives, dispersants and an antioxidant.
The base oil, too, may consist of a combination of substances in order to reach the desired viscosity. Base oils are commonly divided into mineral, vegetable and synthetic oils. The drawback for biolubricants is that (in market statistics, for instance) no distinction is made between types of synthetic base oils, i.e. whether they have been manufactured from mineral or vegetable oils.
Either type of oil may have excellent biodegradation and toxicity performance, but when it comes to sustainability, in terms of using renewable materials, a synthetic base oil manufactured from vegetable oil will often outperform a synthetic base oil manufactured exclusively from mineral oil. (for more information read Benefits and environmental performance)
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An important part of the available lubricants is manufactured on a basis of semi-synthetic derivatives of vegetable oil (mainly rapeseed oil) and animal fat. The semi-synthetic lubricants are esters of an alcohol (often trimethylolpropane (TMP) derived from petrochemicals) and fatty acids (often derived from rapeseed oil).
The distinction between mineral, vegetable and synthetic can also be found in the base oil classification that is being used by the Verband Deutscher Maschinen- und Anlagebau (VDMA) for hydraulic fluids. The VDMA sheets indicate the minimal technical properties for the application of ecological hydraulic fluids (for more information: Technical requirements).
Hydraulic fluids based on triglycerides (HETG) or ‘Pure Plant Oil’ (PPO) Hydraulic oils based on esters (HEES); Hydraulic oils based on polyglycols (HEPG).
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Hydraulic oils and greases are biolubricants used in open and closed systems. A distinction can be made between loss lubricants and 'lost lubricants'.
Loss lubricants are greases with a lubricating and sealing function and are applied to prevent wear from friction or to prevent contamination by particles such as sand during excavation works (and are, therefore, constantly applied under pressure). The nature of their application makes emission into the environment inevitable. This particularly applies to the use of greases and oils to lubricate (semi-) open systems such as stern tubes and gearboxes, but also to concrete release agents.
The lost lubricants are mainly (hydraulic) oils in equipment and installations such as winches and hoisting mechanism, on machines, vehicles and vessels, that are not only used for lubrication but also for the transfer of force. These lubricants are usually applied in closed systems but can end up in the environment due to leakage of the system caused by wear on an installation or during an accident such as a pipe fracture. The application of biolubricants is particularly recommended in loss lubrication and in hydraulic systems in or near ecologically sensitive areas such as nature reserves, agricultural areas and coastal and inland waterways. The use in other applications, however, offers important benefits to the environment as well.
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Lubricants are used in various ways and for many different applications. Depending on the technical specifications and whether it is used in an open (loss lubrication) or closed system (circulation), it is possible to choose from a wide range of oils and greases. For this reason, different types of lubricants are defined when ecolabel criteria are drawn up.
Regional or national ecolabels (such as The Blue Angel,Swedish Standard and Nordic Swan) are in general developed for the following lubricant types: hydraulic fluids, greases, chainsaw oil and concrete release agents.The European Ecolabel for Lubricants defines the following types of lubricant (after the 2010 revision):
- Hydraulic fluids and tractor transmission oils;
- Greases and stern tube greases;
- Stern tube oils, chainsaw oils, concrete release agents, wire rope oils and other total loss lubricants;
- two-stroke oils (for application on land and water);
- Industrial and marine gear oils.
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Ecolabels are mainly geared towards loss lubricantsor products that may cause damage to the environment as a result of accidents. Biolubricants have a lower impact on the environment because they pose little threat to surface and marine life (and contain fewer health risks); preferably, they consist primarily of renewable raw materials.
Pollution can be limited by using biolubricants. Biolubricants are also safer with regard to occupational health; they cause less skin irritation, have a higher flash point while also retaining the correct viscosity, contain lower levels of volatile organic compounds (VOCs) and have a lower emission of VOCs. The use of biolubricants can have a positive influence on costs such as environmental fines, safety fines, by reducing liability and cleaning costs in the event of spills and accidents.
Using biolubricants based on renewable raw materials decreases the dependence on fossil fuels. The current climate crisis has increased awareness of the influence of the application of lubricants on the use of energy by hydraulic engineering objects and installations. And with good reason, too: it is claimed that applying certain lubricants (regardless of whether they carry an ecolabel) may reduce energy costs by as much as 10% to 25%. However, no ecolabel has introduced any such requirement yet.
However, there are criteria that dictate therenewable raw material content. In the European Ecolabel for lubricants, this requirement is set to 50% for hydraulic fluids, 45% for greases and 70% for loss lubricants. The Blue Angel Ecolabel states that the base oil of greases, which constitutes approximately 80% of the final product, needs to consist of either vegetable or synthetic esters. This limits the amount of fossil raw materials and CO2 that are released into the ecosystem. Concerns about the sustainable production of feedstock for base oils has resulted in the development of certification systems for certain feedstocks. Palm oil can be bought certified by theRSPO Soya oil can be bought certified by the RTRS.
The use of biolubricants can, in addition, save more energy because of a higher viscosity index and improved heat transfer. The advantage of a higher viscosity index is that there is a wider range of products available with lower viscosity classes for certain applications of biolubricants. This is not the case with mineral lubricants. The lower viscosity of biolubricants, combined with its improved heat transfer, will sharply reduce energy consumption.
The influence of the applied lubricant on the energy consumption of installations (and on the greenhouse effect and CO2 emissions) is determined primarily by friction. Eventually, wear of parts and the lubricant's life span can also have an effect. If these effects can be sufficiently and reliably quantified, this could for instance be included in the next revision of the European Ecolabel's criteria by means of Life Cycle Analysis (LCA) studies.
In various European countries and regions, ecolabel institutions have drawn up criteria that lubricants have to meet in order to be allowed to carry an ecolabel. Lubricants can be considered for ecolabels (such as Blue Angel, Swedish Standard or Nordic Swan ) if they meet criteria regarding: biodegradability (biodegradation, persistence andbioaccumulation potential), (aquatic) toxicity,renewable raw material content and other environmental and health risks.
A comparison between ecolabels shows that no two labels are the same. In order to harmonise the various definitions, the European Ecolabel for lubricants was created in 2005. Within the current market supply,two classes of biolubricants may be distinguished. For more information refer to: Placing sustainability requirements on purchasing biolubricants
Waste hydraulic oil and grease should be treated like hazardous waste. This also applies to ecological products. The ecological base oil can still contain additives that are hazardous to the environment. Additionally, through its application the oil may, for instance, have become polluted with metal particles. If waste oil is not properly removed, it may pose a risk to soil and water ecosystems. Therefore, the collection and safe removal must be guaranteed. To ensure this happens properly, all waste oil must be collected by a chemical waste collector.
In European Green Public Procurement documents (on Transport) it is recommended that used oil is collected and processed separately. An additional requirement could be inserted in the clauses of passenger car lease contracts and in the agreements with public transport, refuse collection and other heavy vehicles to the effect that a minimum of 25% rerefined base oil ought to be used on maintenance. To that end, relevant environmental aspects and supposed energy and sustainability gains should be analysed further in a Life Cycle Analysis (LCA). In order to have a system in which re-refined engine oil is used on a large scale, the collection and management of the waste lubricants through authorised waste collection points (e.g. garages, petrol stations, bunker stations etc.) must be guaranteed. |
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