Something i don't get about synth, dino and blends

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If a particular oil meets an exact spec from the manufacturer of your vehicle and of an appropriate viscosity, then what's in the bottle can remain a mystery and still do the job. All you have to do is change it when required and refrain from messing with additives in a misguided effort to improve the process. That is enough to take care of engine lubrication. Now all you have to do is mind the other maintenance needs and drive with reasonable care depending on the depth of your pocket book.
 
A few things:

GTL - this is a group III because it is made the same way as a group III. The natural gas is turned into a 'slack wax', which is then used to feed a hydrocracker to get the base oil. With a crude-derived group III, the feedstock is extracted from the refinery, then used to feed the hydrocracker. It is only step 1 of the process that differs, the rest is effectively the same.

PAO - this is derived from gas, but the gas (ethylene) is used to make alpha olefin (decene), which is then polymerised to make whatever PAO you want (different viscosities require different molecular sizes). However, when people say "GTL" they don't mean PAO.

But in the end, as stated several times, the ingredients are largely unimportant - it is the results that are important, and as a consumer these are what you can and should use to determine suitability for your application.
 
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I just can't believe a hydrocracked mineral base has "uniform" sized molecules.
That's marketing not science.

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So show me your lab tests that confirm your beliefs about the GIII base oil molecules not being of uniform size.

Then explain why they would go to all the trouble of hydrotreating it if the end result is the same as a mineral oil.
 
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As previously stated, legalese and big money have clouded the issue.

Group I, II and III all come from nature. They might be filtered, treated, cracked etc etc but they all originate from decomposed animal&plant matter. They are natural, mineral oils.

Group IV & V are manufactured in labs by men in white coats. They do not come from nature.
These are synthetic oils.

That says nothing of performance, add pack etc, but the fact of the matter is one of linguistics. If it comes from nature it is natural, ie mineral.
If it comes from laboratory synthesis, it is synthetic.
 
Originally Posted By: Olas
As previously stated, legalese and big money have clouded the issue.


As does over-simplification.

Originally Posted By: Olas
Group IV & V are manufactured in labs by men in white coats. They do not come from nature.
These are synthetic oils.


And where do the materials that the "men in white coats" use come from? Out of the ground, that's where. PAO comes from ethylene that comes from a refinery. Esters come from acids and alcohols which are made from refinery outputs.

Also, they are made in chemical plants by men in overalls and work boots, just like a refinery.

And, by the way...

Originally Posted By: Olas
Group ... V are manufactured in labs by men in white coats. They do not come from nature.
These are synthetic oils.


...is false. Group V includes medium- and low-VI mineral oils, napthenic oils and vegetable oils... none of these are your definition of "synthetic".
 
GTL HAS to be synthetic under that definition Olas, it's building something desirable out of smaller building blocks.
 
Originally Posted By: Clevy
Originally Posted By: Danh
It's true that synthetic oils sold in North America have base stocks partly made from crude oil. But, the crude is processed in a considerably different way than it is for conventional oil. Conventional oil molecules (Group II) are of varying shapes and sizes even after processing. The extra refining to make synthetic oil out of crude oil results in molecules of a uniform size and shape, which makes them perform better.

Current North American synthetics are typically a blend of extra-refined crude oil, PAO and esters. Pennzoil synthetics are now made with base stocks made from natural gas.

So synthetics are much more than conventional oils with more additives. While some look down at crude oil-based synthetics, they offer performance similar to other synthetics at a better price.





I just can't believe a hydrocracked mineral base has "uniform" sized molecules.
That's marketing not science.

Though the cool pictures are nice to look at


OK. Would "much more uniform" make you happier?
 
It's a silly "ball bearing" analogy that oil companies have used to try to market a perceived advantage to their product...it is baseless in reality, just pitched at dumbfolk.

The process results in molecules that are stringy, long, planar, and have fewer double and triple bonds than that dug from the ground...that's got nothing to do with, or look like, more uniform marbles (square or round depending on the marketting group).
 
I completely agree Shannow - I never liked the way molecules were presented as behaving like solid objects.
 
FWIW, personally, I don't see as sharp a demarcation as some on the terms "dino" vs. "synthetic". The Group category is much more straightforward for me. JM2C.

For final use all contain a blend of molecule sizes as part of the blending process, much like fuels such as gasoline, diesel, and heavy fuel oil contain boiling ranges of molecules as opposed to high purity propane for example. But the ranges of molecule sizes and structures in lubricants are generally more narrow than in fuels.

Group I typically only uses solvents to extract molecules that are less desirable as lubricants from a specific boiling range of molecules distilled from crude oil base, leaving a mixture of molecules with more desirable lubricating properties behind. No real chemical reaction is involved, just selective boiling & condensation (distillation) and solvent extraction.

Group II adds reacting the molecules with desirable lubricating properties with hydrogen to remove by chemical reaction conversion more undesirable atoms & molecules to produce stocks with better stability with respect to temperature, oxygen, etc. This might be performed on both virgin distilled fractions of crude oil as well as certain cracked stocks from fluid catalytic cracking for example where even larger molecules were first distilled then broken up molecularly then again distilled into different "cuts" - gasoline, heavy distillate, etc. A wider range of crude oils can be used to produce the molecules with desirable lubricating properties than simple distillation and solvent extraction. Chevron even defines the 'unofficial' Group II+ stocks, at least with their definition.

http://www.chevronbaseoils.com/faq.aspx

http://www.motivalubes.com/FAQ.htm


Group III in general is selectively making something smaller from bigger molecular building blocks that originally came out from underground. This is an even higher degree of chemical reaction and molecular manipulation than Group II. A much wider range of crude oils can be used for this process. Hydrocracking and maybe fluid catalytic cracking prior to hydrocracking are generally involved. This includes ExxonMobil Visom as well as others. I see some use a GroupIII+ designation (Visom) but this is an 'unofficial' designation

http://www.exxonmobil.com/UK-English/Basestocks/PDS/GLXXENBSKEMVisom.aspx

GTL is building something bigger from smaller molecular building blocks that came out from underground, but can involve selectively breaking the larger building blocks (cracking) as well to obtain the desired molecule size range (i.e. cracking of slack wax that was built up from methane molecules). As the carbon chains build, hydrogen is released from the molecules to make room for the increased carbon to carbon bonds. That same hydrogen (plus any additional required) will then be re-used in the cracking process to produce the series of desired molecule sizes. Shell named their process PurePlus Technology.

http://www.shell.com/global/future-energy/natural-gas/gtl/products.html

http://www.machinerylubrication.com/Read/422/gas-to-liquids



Group IV Polyalphaolefins (PAO) is building something bigger from smaller building blocks (oligimerization), but the smaller building blocks generally came from cracking larger building blocks that came out from underground (fluid catalytic cracking and / or steam cracking is typically used to produce the ethylene from petroleum, although some ethane from natural gas liquids that came from underground is dehydrogenated to make ethylene). For ExxonMobil, oligimerization is eventually followed by selective hydrogenation. ExxonMobil and Ineos are the largest producers. ChevronPhillips is also a significant producer of PAO.

http://utsrus.com/documents/seminary_doklady/exxon_mobil_pao.pdf

http://www.ihs.com/products/chemical/technology/pep/reviews/exxonmobils-ultra-high-viscosity.aspx

http://www.cpchem.com/bl/pao/en-us/Pages/default.aspx

Group V is a catch-all for everything that doesn't fit in the other groups. I worked as an engineer at a refinery that produces pale oils from crude oil that comes out of the ground in a separate set of units from the main refinery that produced typical fuels. The Green Earth Technologies bio-based oil is also classified as Group V. So Group 5 can include stuff that came from underground after cooking as a stew for millions of years as well as stuff grown just this year. Think of Group V as "None Of The Above".

http://www.getg.com/G-OIL_motor_oils.php

http://www.getg.com/G-OIL/bio-based_advanced_full_synthetic_motor_oil.php

Oils in every one of these groups endure some form of separation process, such as distillation, sometimes before, sometimes after, sometimes before & after being consolidated into the desired process stream. There are degrees of 'uniformity' in all of them.

Hope this helps. Kinda long-winded but as with many things it's not as simple as it seems on the surface.
 
FYI, molecules dug up from the ground have very, very, very, very few double and triple bonds (as in negligible) except for aromatic compounds which do not have good lubricating properties. Synthetic crude oils such as those made from shale oils contain such materials only because of the methods used to extract them from the rocks (I'm not talking about fracking, I'm talking about the shale oils / kerogen that was tried in Western Colorado for a number of decades). Similarly for tar sands - the conversion process of the tar into synthetic crude oil produces such compounds (i.e. 'synbit'). It's due to human molecular manipulation, not geological processes.
 
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