Why are Shell GTL oils only Group 3

[virginoil]

http://gasprocessingnews.com/features/20...atural-gas.aspx

Hi

I am trying to get a better understanding of Shell GTL oils why are these considered only Group 3 even after all the vacuum distillation etc treatment.

I endeavored to read the link above which goes thru the conversion process from Gas to Liquid.

However is it because of it is ????? comapred to PAO ???? because of ??? in a nut shell answer.

Are the GTLs group properties closer to the XHVIs oils mineral or closer towards Group 4.

Yes you will I note I need a layman's simplistic answer.

 

[Quattro Pete]

The group classification is primarily based on Viscosity Index. VI of GTL falls within Group 3.

I will repeat myself here for the n-th time, but let's focus on the performance of the end product and less on individual ingredients that it's made of.

 

[Quattro Pete]

FYI... in case you haven't come across this before. A bit dated, but still some decent elementary info...

http://zddplus.labecon.com/TechBrief10 - Oil Base Stocks.pdf

 

[virginoil]

Originally Posted By: Quattro Pete
FYI... in case you haven't come across this before. A bit dated, but still some decent elementary info...

http://zddplus.labecon.com/TechBrief10 - Oil Base Stocks.pdf



Pete this thread is not about GTLs are better than PAOs rather just the science in simple terms regarding their classifications.

Eg do GTLs need the same esters as PAO to contend with seal shrinkage.

Regards

 

[OVERKILL]

I imagine one of the key differences (as touched on in another thread) is that PPD's would need to be used with GTL, whilst they don't with PAO.

 

[virginoil]

.

 

[OVERKILL]

As per this post:

Originally Posted By: bobbydavro
Yeah says PAOs don't have wax. Group III do and that's why you use PPD



This was in response to my comment that these charts said a lot:

WHich KrisZ posted.

 

[JHZR2]

Because that is where they reside according to chemical functionality. Since they are produced from a reaction that polymerizes CO and H, they cannot be defined as group IV (synthesized hydrocarbon, generally alpha olefin polymers) or V (generally defined as products of reactions of acids and alcohols). Keep in mind that the use of base stock group numbers has changed over time, and some have even been removed!

From the shell patent

Quote:
Suitable base oils for use in the lubricating oil composition of the present invention are Group III mineral base oils, Group IV poly-alpha olefins (PAOs) , Group III Fischer-Tropsch derived base oils and mixtures thereof.

By "Group III" and "Group IV" base oils in the present invention are meant lubricating oil base oils according to the definitions of American Petroleum Institute (API) for category III and IV. These API categories are defined in API Publication 1509, 15th Edition, Appendix E, April 2002.

Fischer-Tropsch derived base oils are known in the art. By the term "Fischer-Tropsch derived" is meant that a base oil is, or is derived from, a synthesis product of a Fischer-Tropsch process. A Fischer-Tropsch derived base oil may also be referred to as a GTL (Gas-To-Liquids) base oil. Suitable Fischer-Tropsch derived base oils that may be conveniently used as the base oil in the lubricating composition of the present invention are those as for example disclosed in EP 0 776 959, """ O "~


It's also pretty telling in terms of what they'd like vs what they can do practically to meet specs.

Quote:
There is a strong preference for using a Fischer- Tropsch derived base oil over a PAO base oil, in view of the high cost of manufacture of the PAOs. Thus, preferably, the base oil contains more than 50 wt.%, preferably more than 60 wt.%, more preferably more than 70 wt.%, even more preferably more than 80 wt.%. most preferably more than 90 wt.% Fischer-Tropsch derived base oil. In an especially preferred embodiment not more than 5 wt.%, preferably not more than 2 wt.%, of the base oil is not a Fischer-Tropsch derived base oil. It is even more preferred that 100 wt% of the base oil is based on one or more Fischer-Tropsch derived base oils. The total amount of base oil incorporated in the lubricating composition of the present invention is preferably present in an amount in the range of from 60 to 99 wt. %, more preferably in an amount in the range of from 65 to 90 wt.% and most preferably in an amount in the range of from 70 to 85 wt.%, with respect to the total weight of the lubricating composition.


So they can get away with meeting viscosity specs including 5w and 0w with a majority stake of these GTL group III bases.


http://www.google.com/patents/EP2398872A1?cl=en

F-T makes lots of waxy byproduct, due to the way plants must be run for thermal control. I've actually been part of a project in the past that was able to adjust the Anderson Schultz flory distribution by having better, innovative methods for thermal management. Those approaches are now licensed last I heard. But regardless, there is lots of post processing to get the right hydrocarbon distribution and wax management from F-T. Those processes are similar between slack wax and F-T wax, which is also likely a reason why they keep them the same.

IIRC, the GTL products are higher than the XHVI slack wax products, so likely drive the group III+ unofficial designation. Remember that vi is one of the main elements of the first three base groups.

 

[NMBurb02]

Why don't GTL base stocks fall into the Group V "everything else" category? Is it because the natural gas is a fossil fuel, where as the sources of Group V base stocks are non-fossilized organics?

 

[Jetronic]

Originally Posted By: NMBurb02
Why don't GTL base stocks fall into the Group V "everything else" category? Is it because the natural gas is a fossil fuel, where as the sources of Group V base stocks are non-fossilized organics?


yes, that.

 

[MolaKule]

Originally Posted By: Jetronic
Originally Posted By: NMBurb02
Why don't GTL base stocks fall into the Group V "everything else" category? Is it because the natural gas is a fossil fuel, where as the sources of Group V base stocks are non-fossilized organics?


yes, that.


What classification group are naphthenic oils and what is the source of naphthenic oils?

What is the primary source of alcohols for making esters?

http://www.zddplus.com/TechBrief10 - Oil Base Stocks.pdf

http://www.lubegard.com/pdfs/What_is_the_Difference_in_ATF_base_stocks.pdf

 

[weasley]

Let's be clear that the GTL base oil process is only different to the crude oil process up to the point that the feedstock goes into the hydrocracker. After that it is the same. The main difference is where the hydrocracker feedstock came from... refined crude oil or polymerised natural gas.

As for API group number, it is quite simple. Groups I, II and III are defined by a few phys-chem properties (sulphur, VI, saturates), group IV is defined as PAO and group V is everything else. As MolaKule points out, this could be a refined crude type (eg medium VI or naphthenics), or a reacted type (esters, glycols, ethers etc), or even a vegetable source (eg castor oil). You can not define group V with a simple descriptor other than "everything not in groups I through IV".

 

[Clevy]

Historically higher the group number,the better the basestock however today technology allows us to use what we once thought as a lesser feedstock and turn it into a high quality base oil. In some cases this base oil can rival finished base oils from higher groups tiers.
Which is great return on investment(input)
So to create group 4 basestocks it costs likely costs more when compared to hydrocracking crude and is of course a better product so it costs the blender more.
With gtl they use what's considered a cheap and plentiful feedstock like natural gas. They do their German rain dance and BAMM,a base oil that can be as good as PAO but in other ways so it may not be as fluid in extreme cold however it's more polar and encourage additive dillution therefore the add pack is more effective at lesser treat rates,thus saving money.
Each has different strengths and weaknesses but definitely hold their own in finished formulation trim thus making an equally performing alternative at a lower price which everyone here understands is why companies exist.
So my point is the technology has begun to indicate that group placement no longer equates to the quality of the finished base oil and it's more about how the process of refinement is classed and feedstock used iirc.
What this means is as we evolve the oil each group class will also evolve so I think it will be common to see base oils from lower number groups leapfrog over and into the performance ranges of the next group and as we develop new processes and better methods of refinement and keep pushing to insure we are using that feedstock in a manner similar to the Native Americans and their use of the animals they hunted.
They wasted nothing,to the best of their ability.
So as we evolve and our abilities improve I believe this will be common from all the basestocks in some capacity.
I think that a pao/gtl blend is game changer in the price department. Each base oil compliments the other in that where one is weak the other is strong so once combined should work synergistically together and require less adjusting with ppd's,VII and the like since the oil has these characteristics naturally no extra elements need be added to control specific behavious and characteristics.
Pao-gtl is the performance of an expensive pao-poe combination for the price of a standard oil change.
Oils like RP and redline use group 4/5 combos in some lines and they historically have cost up to double regular synthetic.
Today this regular synthetic can use gtl and pao thus reducing base oil cost and perform In an equal manner.
Putting quality into the hands of the common motorist.
Where once only racers and mud trucks understood how their engines operated and knew in those hotter more demanding conditions a common oil wouldn't pass the muster and out comes a Benjamin instead of a triple sawbuck for oil that had superior natural characteristics so when these engines are spinning so many rpm the piston is travelling up and down and covering the same distance as the operator there it that superior formulation resisting those extreme conditions for longer and thus limiting potential wear and that saves money.
Today anyone can obtain a quality equal to a product considered top of the line but pay significantly less for it.
Even if it performs slightly lesser overall the cost to consumer is reduced while giving them a higher quality product that was previously used so as their engines began getting this higher quality mix their vehicles began to live longer lives.
Gtl is a valuable tool in the quest for energy and represents how 2 people saw natural gas and how it could be so much more than just heat to homes and buildings.
And in the process showed that if you can learn to see things as though they are a finished product consisting of many parts you can move,adjust,and rearrange these parts creating something with desirable characteristics based on the application.

That was a novel sorry guys. My mind just went on rambling. Maybe the stress has finally made me snap.
Hope I made sense

 

[virginoil]

Originally Posted By: weasley
Let's be clear that the GTL base oil process is only different to the crude oil process up to the point that the feedstock goes into the hydrocracker. After that it is the same. The main difference is where the hydrocracker feedstock came from... refined crude oil or polymerised natural gas.

.


Is this correct

Are saying whether from gas for crude oil once treated the feedstock that goes into the hydrocracker is the same from either source.

After the feedstock has been hydrocracked its the same from there on as well except for the GTL based feedstock the HTHS properties are improved etc

 

[weasley]

I didn't say they were the same, I said the process was the same. The GTL feedstock will be different to a crude-derived one by virtue of their genesis, but essentially you end up with a slack wax that is then hydrocracked to get the finished oil.