Synthetic oil
From Wikipedia, the free encyclopedia
Synthetic oil is oil consisting of chemical compounds which were not originally present in crude oil (petroleum) but were artificially made (synthesized) from other compounds. Synthetic oil could be made to be a substitute for petroleum or specially made to be a substitute for a lubricant oil such as conventional (or mineral) motor oil refined from petroleum. When a synthetic oil or synthetic fuel is made as a substitute for petroleum, it is generally produced because of a shortage of petroleum or because petroleum is too expensive. When synthetic oil is made as a substitute for lubricant refined from petroleum, it is generally to provide superior mechanical and chemical properties than those found in traditional mineral oils.
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[edit] Synthetic oil as a substitute for crude oil (petroleum)
One form of synthetic oil is that manufactured using the Fischer-Tropsch process which converts carbon dioxide, carbon monoxide, and methane into liquid hydrocarbons of various forms. This process was developed and used extensively in World War II by Germany, which had limited access to crude oil supplies. Germany's yearly synthetic oil production reached millions of tons in 1944. It is today used in South Africa to produce most of that country's diesel.
Another form of synthetic oil is that produced at Canada's Syncrude oil sands plant. This huge facility removes highly viscous bitumen from oil sands mined nearby, and uses a variety of processes of hydrogenation to turn it into high-quality synthetic crude oil. The Syncrude plant supplies about 14% of Canada's petroleum output. A similar plant is the smaller nearby facility owned by Suncor.
[edit] Synthetic oil as a motor oil
The majority of oil lubricants, including many motor oils, are mineral oil distillates of crude oil. However, synthetic motor oils also have a share in the market. Historically, synthetic motor oils have been made from the following classes of lubricants.
- Polyalpha-olefin (PAO) = Group IV base oil
- Synthetic esters = Group V base oil
In the last decade of the 20th century, hydrocracked and/or isomerized (Group III) base oils began to be used in motor oils. These oils are also designated as "synthetic" (although PAO's and esters are sometimes included in a final blend).
[edit] Automotive Use History
Although in use in the aerospace industry for some years prior, synthetic oil first became commercially available for automobile engines when the French Oil company MOTUL first introduced commercial ester-based synthetic-oil in 1971. Other early synthetic motor oils included Amsoil, introduced in 1972 (with an ester-based 10W-40 formula developed by Hatco) and Mobil 1, introduced in 1974 (with a PAO-based 5W-20 formula). Modern formulations have however changed. According to MSDS (Materials Safety Data Sheets) filed by these manufacturers, Amsoil is based on 85% - 95% 1-decene homopolymer base[1], not ester, and Mobil 1 contains only 5% PAO[2]. Red Line Oil produce ester based synthetics[3] although the percentage content is not determined.
[edit] Required Applications
Many modern high-performance vehicles specify synthetic motor oils. Some manufacturer specifications include:
- GM-LL-B-025 (diesel engines)
- GM-LL-A-025 (petrol or gasoline powered engines)
- VW 502.00/505.00/503.01 (includes both diesel and petrol or gasoline engines)
- MB 229.5 (DaimlerChrysler)
- BMW Longlife 01
- Honda HTO-06
- Porsche Approval list 2002
Various motor oils made from Group III, Group IV, and/or Group V base oils are on the market that meet one or more of these manufacturer specifications.
[edit] Advantages
The benefits for synthetic motor oils include:
- Better low temperature viscosity performance.
- Better high temperature viscosity performance.
- Decreased evaporative loss
- Reduced friction
- Reduced engine wear
- Improved fuel efficiency
- Chemical stability
- Resistance to oil sludge problems
- Some synthetic motor oil producers offer extended drain intervals
[edit] Disadvantages
The disadvantages of synthetic motor oils include:
- Initial cost
- Potential oil seal problems - if the oil does not contain sufficient seal conditioners.
- Potential decomposition problems in certain chemical environments
- Potential stress cracking of plastic componentry like POM (polyoxymethylene) in the presence of PAO's.
Initial cost may be mitigated by extended change intervals, but those need to be confirmed by oil analysis for each particular user.
[edit] Semi-synthetic oil
A semi-synthetic oil (also called synthetic blend) is a blend of mineral oil with no more than 30% synthetic oil. They are designed to provide many of the benefits of synthetic oil without matching the cost of pure synthetic oil. MOTUL introduced the first semi-synthetic motor oil in 1966.[citation needed]
[edit] Health Issues
A non profit group called AOPIS [4] was set up by crew members in 2001 to tackle the health and flight safety issues of bleed air being contaminated by synthetic jet engine oils and hydraulic fluids in jet aircraft.
