The truth about petroleum products.
 

I just read through a thread regarding the choices individuals make regarding the brand and grade of fuel that they use in the automobiles and I thought that, perhaps, the TFP membership could benefit from a little research that I have.

As a member of the international import and export business community, I have a bit of insider knowledge when it comes to commodities. I was, however, a bit of a fish out of water when a large shipment of petroleum products came from overseas on one of our boats -- we usually don't do tankers. I'm still not entirely certain why my shipping company was moving petroleum, but nonetheless, we were.

Now, to the meat of my presentation.

All gasolines and diesel fuels are covered by ISO standards governing their purities (measured in octane). Octane is an ideal standard and is a gas that will not explode when pressurized (or its difficult to detonate). Heptane, on the otherhand, is the direct opposite. Under even slight pressure, heptane gas will detonate. It is a comparison between heptane (rated @ 0) and octane (rated at 100) that yields the rating that our gasoline fuels receive. An 87 octane gasoline behaves like a mixture of 87% octane and 13% heptane. The higher the rating, the less likely the fuel will be to prematuring detonate from compression instead of the spark (aka., knocking or pinging). These ISO measurements standards (87, 91, 93) are closing followed for one large reason: pipelines.

There are close to 23,000 miles of petroleum pipelines in the United States moving all manner of fuels, ranging from various octanes of gasoline to diesel. The reality of these pipelines is that they only allow for 1 (one) type of fuel to run simultaneously and without any stoppers between fuels types (they switch periodically as demand necessitates) there is substantial mixing. This mixture is usually drained off and used in industry for heating where octane or the gasoline v. diesel isn't important.

The other reality of these pipelines is that all gasoline moves through the same arteries, regardless of distiller or destination companies. Thus, we call all gasolines "fungible" commodities. Remember, ISO guidelines determine that all 87, 91 and 93 rated gasolines are created equal. A distiller pours some quantity X into the pipeline at one end, and drains some quantity X out of the other end. This is simplified, but covers what actually happens.

So, since ISO standards cover what goes in and out of the oil pipelines, what does that mean for consumers shopping at Exxon, Texaco, Phillips 66, etc.? All gasolines are created equal.

The only differences between commercial gasolines are the detergents added by the commecial agents after removing the gasoline from the pipeline and moving it to their distribution centers. Oh, and by the way, most of those detergents come from the same manufacturer -- In actuality, it is the same "stuff" added across the board, in most cases.

So what's the difference between Exxon, BP and Phillips? Their marketing strategies.

So, just remember that the tiger in your tank is just as good as the shell in your tank or the 66 or the BP. Same stuff, no matter where you get it.

PS: Little tidbit you might find interesting about the air that you are breathing right now. Do you think that the US banned lead fuels? Wrong. Piston airplanes, which commonly use 115 octane fuel, are permitted to have the same tetraethyl lead compound that was banned for use in cars (inexpensive boost to octane ratings). Leaded or ethyl fuels = no catalytic converter. Jet engines don't use gasoline at all (kerosene, in fact). So, remember that the next time you see a Cesna overhead.

edit: Quickly cleaned it up a little for Halx

Some websites with information:

http://www4.nas.edu/onpi/webextra.ns...e?OpenDocument
http://www.commongroundalliance.com/
http://www.shellpipeline.com/
http://ops.dot.gov/
http://www.mapl.com/
http://www.kochpipeline.com/
http://www.bppipelines.com/
http://www.colpipe.com/home.asp
http://www.exxonmobilpipeline.com/US...L_Homepage.asp
http://www.expl.com/
http://www.epenergy.com/
http://www.negt.com/

Simplied Map: (doesn't contain all pipelines)
http://www.platts.com/features/ratin...iamsassets.pdf

Keep in mind that smut or particles in the tank has nothing to do with the national distributer and _everthing_ do with with the gas station's tanks. Some scenarios that influence fuel quality:

1) a fuel truck has just made a delivery to the station and stirred up dust at the bottom of the storage tank
2) a heard of elephants took a bath in the tank
3) maybe both 1 and 2, but mostly # 1...

That was a very interesting read. I have three questions that I've been wondering about.

How do fuel companies produce gas with different octane ratings, and does it cost anywhere near the extra thiry cents per gallon that we pay, to propduce?

So if the octane rating is the way gasoline behaves as opposed to a mixture of octane and heptane, does 113 octane fuel take 13% more pressure to detonate than pure octane?

Also, how approximate are the ratings at the pump? I assume that it's impossible to make a perfectly uniform mixture, but how close is it?

This is my new favorite thread.

me waits for more info on MrSelfDestruct's questions :)

All gasoline starts off @ 70 octane and it depends on what the terminal uses to boost octane. There are several different options, but none of them are very expensive. FTC recommendations say that if your car's manual says to use "regular" (87 octane) then use that gasoline. No benefit of horsepower will be gained by using high octane fuel -- its wasted on smaller engines. None whatsoever. Its not even cleaner. If your engine knocks or pings, then definitely upgrade to a higher octane fuel because _long term_ knocking will destroy your engine. But, unless you're driving a Porsche with twin turbo, you probably won't have ANY problems with 87 or 89 octane fuel. To answer your question though, since all gasoline is distilled at 70 octane, and all fuels must have additives to boost octane, then no -- its not that much more expensive to boost octanes to 91 or 93 beyond the 87 required by law. The question is, do you NEED the 91 or 93. Probably not...

I believe that most 113 gasoline uses ethanol to increase its rating. Since the octane scale is a relative one, then greater than 100 ratings exceed pure octane's pressurization point -- meaning, you can pressurize the fuel/air mixture further than pure octane before it detonates without a spark. This is important in high compression engines like airplanes and nascar. Remember, the octane rating system is only a _comparison_ of gasoline to pure isooctane ... (BTW, a 9:1 ratio of gasoline to pure ethanol will yield 3 additional octane points)

Fairly close. There is a process by which, a single cylinder engine is run using the gasoline in a lab. There are 2 averaged measurements that go into the tabulation of the total octane rating of a gasoline. These are in turn, averaged together. The sample pools are large enough to account for some margin of statistical error. Basically, the numbers are close enough to their integer labels. The only errors occur in the decimal places...

Thanks Tritium for your thorough analysis on gasoline. I know I have learned a lot after reading your posts.

Definitely an interesting read. I'd always wondered how that worked. Now, I'm more enlightened! Who says you can't learn new stuff?

Very interesting stuff on gasoline. I read an article yesterday from Consumer Guide that says it's actually possible for the octane requirement of your car to increase as it gets older, because built-up crud in your cylinders can increase the compression and temperature.

http://auto.consumerguide.com/auto/e.../act/feature21

Elite, that is absulutely true. I just upgraded to midgrade gas for my jeep, at 250k miles. Its needed it for that last 20-30k or so, but it finallly got to the point where it REQUIRED it. As your fuel burns (a series of hydrocarbons), some of the carbon gets into your cylinder. This takes of volume, and subsequently raises the compression ratio. This increases heat and pressure, and so your gas can ignite too early. This is bad for the cylinders and horrible for the pistons, but its also produces more NOx (a major component in photochemical smog). The higher grade gas takes more pressure to ignite, and thus doesn't burn until the spark hits. Couple cents more a gallon, but on a whole tank, 2 bucks to dramatically increase engine life is reasonably cheap insurance.

Tritium, great post. Another question for you:
Here in Australia, most petrol stations have standard fuel rated at 93 Octane, and a 98 Octane 'Premium'.
From what I've read from the internet, 98 Octane is not readily available in the US. What do you think is the reason for this? I would have thought the US had more high performance, cars than us Aussies.

Excellent posts! Very informative.

I'd have to do more research on Aussie fuel lines, distilleries and terminals. I really couldn't put my finger on any one reason why the octanes would be different between US and Australia but it almost certainly has to do with the different additives used betewen our continents to raise octane levels. Gasoline distills at the same natural octane rating from crude oil regardless of which continent you are on. Logically, the only reasonable explanation I can think of would be different emissions requirements necessitating different fuel additives.

Your gasoline might contain more ethanol, for example, and, therefore, have a higher standard octane. Not sure. Are leaded fuels legal over there? The lead additives used in the US were added to cheaply raise octanes -- could be that they are still legal on your side of the Pacific for civilian ground vehicles.

But, I think that you get the general idea. Laws and regulations on emissions and the prices of available octane boosting additives probably influence what octanes the terminals crank out.

Now that I answered the inverse of your intended question ...

Legal (!) Fuel additives are more expensive over here. Propaganda (sp?) and legislation have pretty much locked our gasoline market into 3 standard octanes based on a limited array of fuel octane boosters. It probably also has to do with the lack of mobility for change in our established and old distribution networks.

It also speaks to how old our cars are too. The above posts speak to a natural desire of Americans to dispose of old automobiles before they decompose completely -- not to imply that Aussies are driving clunkers. Kia, Daewoo, Hyundai and (originally) Saturn were founded on the premise of a disposable car. Geo too.

The truth is probably in there somewhere. Its a pretty broad question with a lot of complex variables influencing the reality of our 3 standard octanes.

Absolutely true. Ever had a gasoline engine "diesel" for a few seconds after turning the ignition off? Old engines are usually dirty with carbon after slowly and increasingly consuming their lubricating oils over their years. It happens...

What do the R and M stand for in "R+M/2"?

Wow, all I know is that 90% of the time when I see what Holden, Ford, and others are bringing out in Oz, I weep at the anemic, FWD garbage we're seeing here. Might be a "grass is always greener on the other side" feeling, but it looks like you Aussies have some really nice stuff cruising your roads.

No, the US in general doesn't have more high performance cars. Typically, our higher end sports sedans (mustangs, etc. ) are underpowered compared to foreign models. This is due to the US having very strict emissions requirements. Other countries (such as Australia) dont have requirements quite as tough as ours, and thus can run dirtier cars. With that increase in pollution come a very nice increase in power. But to get that power, the cars REQUIRE a "high performance" gasoline. Your engines typically have a higher compression ration for better performance. They can do this through different engine parts, or forced induction. To keep the gas from igniting early under these conditions, higher grade gas is used. If higher compression engines are more standard in Aust. than in the US, it would make sense for higher grade gas to also be standard.

I have never lived in Australia, so im not positive, just speaking from what i've noticed.

Sadly, nothing could be farther from the truth :P You guys get much faster cars than we do :P

Leaded fuels are now illegal for all private passenger vehicles. It may be a different story for commercial, agricultural and military vehicles, but the petrol stations no longer offer leaded fuel at the pumps.
There was a huge controversy regarding Ethanol over the last year or so. Many of the Petrol Stations/Fuel suppliers were diluting their petrol with ethanol to cut costs. Many consumers found their cars started to ping and knock due to the effect the ethanol had on their engines. Everyone complained because there was no standardised/enforced way of knowing the level of ethanol in the fuel they were purchasing. The topic was covered extensively on 60 minutes/exposay type shows.
The govt finally stepped in and put restrictions on the amount of ethanol that could be used. I think they also made it mandatory to specify clearly if the fuel someone was purchasing contained ethanol or not.
After that, most of the stations stopped the practice, and proudly displayed signs saying "100% petrol. No ethanol used" to restore consumer confidence.

I always thought 'American Muscle' was what it was all about over there! We have a huge Ford Vs. Holden battle going on here at the moment, with each manufacturer trying to outdo each other. I think the current winner, in terms of overall performance is the Ford Falcon GT-P. A V8 that produces 290kW @5,500RPM in stock trim. {Insert Tim the Toolman Taylor Grunting noise}
I guess it would be hard extracting that sort of power if you had to run 92 Octane.

You are correct. But us Aussies dont have it all. Alot of our High Perfoamnce imports (mainly from Japan) also come detuned.
Alot of performance vehicles from Japan are tuned to run at 100 Octane, so cars like the WRX STi that are imported into Oz have been detuned so that they run better and more reliaby with 98 Octane availble here.

mind if i field this one?

R is short for RON, or Research Octane Number.
M is short for MON, or Motor Octane Number.

When a blend of gasoline is tested, its tested by both methods, RON and MON. RON tends to be higher, and is what you would find in a laboratory setting. pure science there, that is.

MON, on the other hand is garnered using real world testing results.

so the two numbers are added, then divided by two to get PON, or Pump Octaine Number.


oh, and me? i just dump straight BTX into the tank!

which is why i shop based on price :)

tritium,
I had another question I thought you would be able to answer.
A friend of mine told me that the octane rating in fuel purchased from the pump goes down 1 to 2 octanes whilst in your petrol tank over the course of a week. Any truth to that? I've noticed in my car, that it does not drive as well when the tank is nearing empty, although I had always put it down to a fuel filter or fuel pump which needed replacing....

Crude type will make a more or less acidic gasoline by sour crude containing way more sulfur than sweet crude. it is very hard to remove the sulfur completely therefore it is better to get gas that is made from sweet crude versus sour crap. les acid less wear and acidic oil to eat away at your valuable engine parts.
Refineries test the octane in the gas by running little engines and adjusting the timing, then they blend accordingly.

Best thread ever....no if I can learn why gas prices are rising

Heh, prices went up 6 cents over the weekend...

fuckers. 1.75 for the cheapest stuff is just wrong.

Holy crap I never knew. I was tricked by marketing. :mad:

Great Post!!!

FYI They (CNN) said that Oil production will be increased before summer. ( I could find the link, but it was off of yesterdays CNN page.) A long time friend of President Bush runs / owns? one of the Big Oil producers. Explained that with the lack of production it's also hurts world economics to, and to help offset he would have production increased.

So hopefully prices will come down... I hope!

You guys complaining about pricing. We're paying around 75 to 80 pence per liter in the UK. Per UK gallon that works out at about £3.60. Current exchange rate is favourable, figures over 2 dollars per gallon. Normally more like $2.40 or upwards. The current hike in taxation has been held off for a few months as well.