MTBE

[revn247]

Hi all!
This is my 1st post to this list since joining. I've gained much knowledge from all of you. Thank you!
Now for the question (s). Out here in socal, Union 76 stations are now advertising "NO MTBE". What oxygenate are they using instead? And why the switch? (most likely health/epa reasons?)

Thanks again.

 

[MolaKule]

MTBE is "MethyTeriaryButyl Ether," a derivative of isobutylene, the same stuff that is used in synthetic rubbers and oil thickeners and tackifiers.

MTBE was used as an oxygenator and antiknock compound. The primary use of MTBE was to help reduce smog in places like LA.

However, it was found, that like tetraethyl lead, it has a long lifetime and is poisinous to certain organisms.

Ethanol, a grain-based alcohol, is now replacing the MTBE as an oxygenator. Ethanol is simply "white-lightening" added to fuel in a 90% fuel, 10% ethanol mix. It raises the octane about 2-3 points.

 

[Jay]

Neither oxygenate does a thing to reduce emissions in a closed-circuit fuel-injected engine. The MTBE poisons water supplies, and alcohol can attack seals and make a mess of your fuel system. The oil companies favor oxygenates because it reduces the BTU of their fuel so people have to buy more. The EPA favors them because it's another way of going through the motions of solving the pollution problem without actually doing anything constructive.

Are you sure the 76 stations are using another oxygenate? I would buy gas from them if they weren't using any of them.

 

[MolaKule]

"and alcohol can attack seals and make a mess of your fuel system. The oil companies favor oxygenates because it reduces the BTU of their fuel so people have to buy more."

I am not so sure I agree with all you state.

In low concentrations, ethanol should have little effect on seals. The oil companies didn't want to blend ethanol because it was a fuel competitor and championed by the Dept. of Agriculture and price supported as well.

The only two disadvantages to ethanol I have heard discussed is that if left in a tank for a long time, it will leave a coating of varnish if stabilizers are not added to the blend. Secondly, it does NOT have the same energy potential as gasoline, so mpg may suffer a bit.

Now methanol is very corrosive and will degrade a seal quickly.

[ November 03, 2002, 11:33 PM: Message edited by: MolaKule ]

 

[SteveD2]

quote:

---

Originally posted by Jay:

....
Are you sure the 76 stations are using another oxygenate? I would buy gas from them if they weren't using any of them.

---

--quote--
Phillips, which markets under the brand "76," announced in July they had completely ended the use of MTBE in their commercial fuels in the state, replacing it with ethanol.
--end quote--
http://www.ethanolrfa.org/ereports/er090602.html

 

[csandste]

In the St. Louis area there seems to be more alcohol than MTBE which is rumoured to be nasty stuff indeed. (We also have vapor recovery hoses.) A neighboring city is talking about forbidding MTBE-- don't know if they can do that, they also wanted to ban BP signs because they're green and yellow and not "American" like Amoco red white and blue-- don't think they can do that either.

Anyway, for what it's worth, MTBE seems to get about 10% better fuel efficiency.. although the stuff I can find in rural Missouri seems to do better still.

 

[revn247]

so if ethanol increases octane, i guess the "new" fuel starts out at a *lower* octane rating. sorry, newbie q.
The prices are still competitive with other major brands though. I would think it would be cheaper by using ethanol.
And I dont see how you can outlaw a business logo like BP.

 

[BOBISTHEOILGUY]

I had posted some comments/thoughts on this subject a long time ago in my FAQ's section
WHAT DO YOU THINK OF GASOLINE BLENDED WITH 10% ETHONAL?

WHAT DO YOU THINK OF GASOLINE BLENDED WITH 10% ETHONAL? I HEAR IT'S BAD ON SEALS
Oxygenates are added to increase the octane of gasoline and MTBE is the most common. Oxygenates are added to more than 30 percent of the gasoline in the United States, and by the end of this decade, it is estimated that oxygenates will be added to 70 percent of the gasoline. MTBE is being replaced with ethanol due to EPA health concerns.
gasoline mixed with ethanol is alot of times called gasohol, a gasoline extender made from a mixture of gasoline (90%) and ethanol (10%; often obtained by fermenting agricultural crops or crop wastes). gasohol has higher octane, or antiknock, properties than gasoline and burns more slowly, cooler, and completely, resulting in reduced emissions of some pollutants, but it also vaporizes more readily. ethanol-based gasohol can damage rubber seals and diaphragms if the ethanol is present in higher concentrations. only time will tell just how much if any damage is going to incur with injectors and such.

my thoughts on this would be that rubber seals around injectors and such would be more prone to deteriorate due to this, and that a fuel additive that has a good lubrication property would help reduce this problem.

 

[MolaKule]

Up in Iowa, Wisconsin and some of the other "corn belt" states the use of ethanol
blends has been around for over 15 years. Never heard of anyone replacing carburateur or fuel injector seals because of the fuel type used.

I would think that the use of some type of stabilizer (like Neutra) in the fuel tank (if the fuel was going to sit a while) would keep any acids from occuring.

I would think that acids and strong solvents would cause more problems with seals than would 10% ethanol blends.

 

[Jay]

I understand that MTBE has been used as an octane booster long before it became popular in oxygenated gasolines. I have no objection to that. But I still believe that it's use as an oxygenator is completely unneccessary in modern engines. It has no benefit in reducing pollution.

Between MTBE oxygenated gasoline and gasohol, I'll take the MTBE any day. And thanks, Union 76, for the warning. My owners manual says I can use MTBE up to 15% by volume, but only 10% ethanol. Methanol can't be used at all.

 

[MolaKule]

"so if ethanol increases octane, i guess the "new" fuel starts out at a *lower* octane rating. sorry, newbie q.
The prices are still competitive with other major brands though. I would think it would be cheaper by using ethanol."

Most unleaded fuels start out at 87 octane or lower and the octane rating is raised by the addition of ethanol.

 

[Ferb]

Jay, i remember reading somewhere, that the necessary ethanol additive was 5.6% to compete with the standard blends of MTBE. But i agree-- the need for oxygenates seems to be based on old thoughts and old technology. Plus it's cheaper and easier to produce MTBE for the oil companies.

Frankly, i like 76's plan. It gives consumers the option of not polluting waterways and ground water. What is disappointing is the cost difference up here. Dunno how it is down in the village, but in SLO the 76 is always more expensive.

ferb!