Alcohol as diesel additive, pros and cons

[Excalibur]

After researching some of the diesel additive MSDS I discovered that alcohols are often included.

Example types found with a quick search include:
2-ethylhexanol (e.g. Caltex, Gulf)
Branched Alkanol (e.g. Techron D)
Alcohol ethoxylate (e.g. FuelDoctors)

Other additive blenders seem quick to proclaim "no alcohols", so I wondered if alcohols were seen as good or bad in diesel??

Alcohols are suggested to be good at dissolving gum/varnish, absorbing water and helps antifoam.
Downside could be seen as the ability to leach water from atmosphere, degrade some seal types or not perfectly miscible.

So, I invite interested parties to contribute with points of view, opinions or experience etc.


Snippet:
According to European standards EN 14214, biodiesel can have up to .2% residual methanol from the production process. Given this allowance spec, it appears that they regard the amount to be harmless for use in a vehicles' fuel system. I believe methanol would require a co-solvent to be miscible with hydrocarbon based diesels.

 

[HerrStig]

Reading about what happens to race engines running on 100 % alky is interesting.

 

[Boomer]

Many TDI owners will tell you that even small amounts of low molecular weight alcohols will destroy the HPFP. Probably truth in that.

Thatai, many of the diesel additives use these higher molecular weight alcohols as LUBRICANTS for fuel pumps if you read the MSDS. Also, there seems to be a divide in whether water should be dropped out of the fuel with a demulsifier or whether it should be fully solulbilized in the fuel.

 

[HerrStig]

Originally Posted By: Boomer
Many TDI owners will tell you that even small amounts of low molecular weight alcohols will destroy the HPFP. Probably truth in that.

Thatai, many of the diesel additives use these higher molecular weight alcohols as LUBRICANTS for fuel pumps if you read the MSDS. Also, there seems to be a divide in whether water should be dropped out of the fuel with a demulsifier or whether it should be fully solulbilized in the fuel.
+1.

 

[Dufus2]

My opinion is water suspended in the fuel becomes corrosive in the tight tolerances of fuel pumps and injectors leading to a short life. I prefer not to use a de-icer type of fuel additive that will pass water through the filter.

 

[totegoat]

If you are interested in a long life diesel, additives aren't needed.

 

[Donald]

Originally Posted By: totegoat
If you are interested in a long life diesel, additives aren't needed.


Unless you have a mechanical injector pump like a Bosch VP44. In that case an additive to make sure there is proper lubricity might be helpful like 2 cycle oil. While diesel should have the needed lubricity additives, I am not sure many people verify and it will really only effect the older mechanical injector pumps.

The 2 cycle oil is 10 cents/ounce. For me thats $3 per fill-up (30 gallons of diesel). The VP44 is $2500.

 

[MolaKule]

Originally Posted By: Dufus2
My opinion is water suspended in the fuel becomes corrosive in the tight tolerances of fuel pumps and injectors leading to a short life. I prefer not to use a de-icer type of fuel additive that will pass water through the filter.


Then does the water just build up in the fuel tank?

Anti-rust, anti-corrosives, anti-oxidants, and bio-stats are added to the fuel mix. [At least for the ones I formulate].

I am in the camp that believes the moisture should be solubilized in order to get rid of it as soon as possible.

 

[demarpaint]

You don't want alcohol in the fuel injection pump. The water separator should take care of the water problem. I'd be afraid of alcohol going into diesel fuel.

 

[Excalibur]

Thanks for taking the time to post. There's some great thought provoking points of view.
I regard everyones' contribution as valid and valuable.

Originally Posted By: HerrStig
Reading about what happens to race engines running on 100 % alky is interesting.
I've had a lot of success using methanol for racing over 20+ years. It's a great fuel for competition work. One caveat was the carburetors had to be drained and engine oil dumped after each event otherwise the methanol would attract moisture rusting or corroding the parts.

Originally Posted By: Boomer
Many TDI owners will tell you that even small amounts of low molecular weight alcohols will destroy the HPFP. Probably truth in that.
Thatai, many of the diesel additives use these higher molecular weight alcohols as LUBRICANTS for fuel pumps if you read the MSDS. Also, there seems to be a divide in whether water should be dropped out of the fuel with a demulsifier or whether it should be fully solulbilized in the fuel.
Mr.Google found this most interesting study Preferred alcohol addition levels are about 0.2 to 0.8 wt %.

Originally Posted By: Dufus2
My opinion is water suspended in the fuel becomes corrosive in the tight tolerances of fuel pumps and injectors leading to a short life. I prefer not to use a de-icer type of fuel additive that will pass water through the filter.
Good point. I'm reminded of 98 octane Gull Force 10 gasoline with 10% ethanol. When the product was released the company warned that residual water in the vehicles' fuel system could cause starting problems till it was eliminated.

Originally Posted By: Donald

Unless you have a mechanical injector pump like a Bosch VP44. In that case an additive to make sure there is proper lubricity might be helpful like 2 cycle oil. While diesel should have the needed lubricity additives, I am not sure many people verify and it will really only effect the older mechanical injector pumps.
The 2 cycle oil is 10 cents/ounce. For me thats $3 per fill-up (30 gallons of diesel). The VP44 is $2500.
Thanks. Yes my IP is a Bosch copy by Denso. There's lots of folks using oil, especially 2 stroke oil as extra lube. It definitely can't hurt in that amount. Look at it as cheap insurance.

Originally Posted By: MolaKule

Then does the water just build up in the fuel tank?
Anti-rust, anti-corrosives, anti-oxidants, and bio-stats are added to the fuel mix. [At least for the ones I formulate].
I am in the camp that believes the moisture should be solubilized in order to get rid of it as soon as possible.
Thanks for posting. Great thought on making the water soluble. Also it's not like it's several gallons of water that needs disposing of! It would likely be just tiny bit every now'n then. Molakule, in your opinion which of the alcohol types is suitable? I have gallons of leftover methanol but am hesitant because of its' corrosive reputation plus it doesn't mix readily.
Would an alcohol be regarded as a detergent in its' own right? Examples I can think of are ethoxylated alcohol as in household detergents, shampoo and the like.

Originally Posted By: demarpaint
You don't want alcohol in the fuel injection pump. The water separator should take care of the water problem. I'd be afraid of alcohol going into diesel fuel.
Thanks. Good idea to be cautious. How do you react to the fact that the industrial giant Chevron have alcohols in their Techron D concentrate?

 

[demarpaint]

Originally Posted By: Excalibur


Originally Posted By: demarpaint
You don't want alcohol in the fuel injection pump. The water separator should take care of the water problem. I'd be afraid of alcohol going into diesel fuel.
Thanks. Good idea to be cautious. How do you react to the fact that the industrial giant Chevron have alcohols in their Techron D concentrate?


How much alcohol and what kind of alcohol does it contain? I would probably research the product more, or look for another product.

 

[MolaKule]

Ethoxylated alcohols serve many functions such as detergents, emulsifiers, and, dispersants.

I would not add any methanol due to its potential for corrosion.

 

[demarpaint]

Originally Posted By: MolaKule
Ethoxylated alcohols serve many functions such as detergents, emulsifiers, and, dispersants.

I would not add any methanol due to its potential for corrosion.



Do those alcohols take way the natural lubricity that diesel fuel provides? My thoughts would be a Kerosene based diesel fuel additive w/o the alcohol would be safer, if something like that exists that can remove water. Still they have a pretty good water separator, and if that is properly maintained it should prevent damage to the pump and injectors caused by water.

 

[MolaKule]

Originally Posted By: demarpaint


Do those alcohols take way the natural lubricity that diesel fuel provides? My thoughts would be a Kerosene based diesel fuel additive w/o the alcohol would be safer, if something like that exists that can remove water. Still they have a pretty good water separator, and if that is properly maintained it should prevent damage to the pump and injectors caused by water.


Even if you have a good water separator some moisture is still going to be present in the fuel and will make its way to the injector rail.

In the dosages present we do not expect those alcohols to interfere with the lubricity of the diesel fuel.

 

[demarpaint]

Originally Posted By: MolaKule
Originally Posted By: demarpaint


Do those alcohols take way the natural lubricity that diesel fuel provides? My thoughts would be a Kerosene based diesel fuel additive w/o the alcohol would be safer, if something like that exists that can remove water. Still they have a pretty good water separator, and if that is properly maintained it should prevent damage to the pump and injectors caused by water.


Even if you have a good water separator some moisture is still going to be present in the fuel and will make its way to the injector rail.

In the dosages present we do not expect those alcohols to interfere with the lubricity of the diesel fuel.


Thanks. The reason for the questions is we are considering the possibility of a diesel engine for our next vehicle. How often do you suggest treating diesel fuel to remove moisture? Is this an every fill up deal?

 

[Excalibur]

Originally Posted By: demarpaint

How much alcohol and what kind of alcohol does it contain? I would probably research the product more, or look for another product.
MSDS of the concentrate shows alcohols @ 1% - 4.9%. The retail bottles are 12oz / 350ml I believe.
Originally Posted By: MolaKule
Ethoxylated alcohols serve many functions such as detergents, emulsifiers, and, dispersants.
I would not add any methanol due to its potential for corrosion.
My thought about methanol and corrosion after using it for racing over the years. The methanol is so effective at cleaning the metal surfaces that when the methanol eventually absorbs water from the atmosphere, it is the corrosion from the water that does the damage. In other words, the metal lost all its' defenses becoming so super clean, it was instantly oxidized by moisture. Just a thought... difficult to prove though.
Originally Posted By: demarpaint

Do those alcohols take way the natural lubricity that diesel fuel provides? My thoughts would be a Kerosene based diesel fuel additive w/o the alcohol would be safer, if something like that exists that can remove water. Still they have a pretty good water separator, and if that is properly maintained it should prevent damage to the pump and injectors caused by water.
In the study I posted in response to Boomer (above), they apparently were able to show that ULSD lubricity improved when added at 0.2 to 0.8 wt %. I wonder if alcohol added in these tiny amounts, being a surfactant is able to modify lubricity because it changes the surface tension of the ULSD??

Originally Posted By: demarpaint

Thanks. The reason for the questions is we are considering the possibility of a diesel engine for our next vehicle. How often do you suggest treating diesel fuel to remove moisture? Is this an every fill up deal?
Given the presence of alcohol in Techron D concentrate, I wondered whether there is alcohol in the diesel at the pump??
After all, here at least both are branded Techron D and the bottled stuff they call their "concentrate".

After doing some study on various alcohols as in the list in post#1, I see that 2-ethylhexanol is called a fatty alcohol
Wiki: 2-Ethylhexanol is a fatty alcohol, an organic compound is a branched, eight-carbon chiral alcohol. It is a colorless liquid that is poorly soluble in water but soluble in most organic solvents.

It is also commonly used as a low volatility solvent. Has a high boiling point. It looks like a good choice.

 

[demarpaint]

^^ Good information, thanks for posting it. ^^

 

[Boomer]

Excaliber, note that in the patent you cited, the alcohols look to be C7 on up to C30. These are higher weight alcohols I was referring to in my original post. That is one reason castor oil was always considered a good lubricant. There is an OH group on the fatty acid side chain(s) that pulls the molecule to the metal surface and helps the full oil molecule bind more tightly ensuring better lubrication.

 

[demarpaint]

I've been thinking about this a bit this morning. If alcohol emulsifies water wouldn't that cause it to get past the water separator and into the pump and injectors causing more harm than good to a diesel engine? I'm having a hard time thinking anything containing alcohol is good for a diesel engine. I don't think it would do the seals in a diesel engine any good either. IIRC some of the old Powerstroke [?] diesel owners manuals warn against using any additives with alcohol in the fuel. I can see it useful in gas, but I'm still learning about diesel.

 

[Excalibur]

Originally Posted By: Boomer
Excaliber, note that in the patent you cited, the alcohols look to be C7 on up to C30. These are higher weight alcohols I was referring to in my original post. That is one reason castor oil was always considered a good lubricant. There is an OH group on the fatty acid side chain(s) that pulls the molecule to the metal surface and helps the full oil molecule bind more tightly ensuring better lubrication.
Yes I understand they are the heavier alcohols and some heavy alcohols are a solid I think I read. Some waxes also have fatty alcohol content. If this was indeed the case I wondered if a wax dissolved in the diesel tank could be a detergent because of the alcohol, a lubricant and the waxiness would mean that no dirt would stick to any surface?
Yes, that castor oil is just legend. It's a pity it don't last and needs draining out of the race engine after each event. Hey, I reckon put a pot of castor on the stove when you're watching motor racing! Really gets you going!

Originally Posted By: demarpaint
I've been thinking about this a bit this morning. If alcohol emulsifies water wouldn't that cause it to get past the water separator and into the pump and injectors causing more harm than good to a diesel engine? I'm having a hard time thinking anything containing alcohol is good for a diesel engine. I don't think it would do the seals in a diesel engine any good either. IIRC some of the old Powerstroke [?] diesel owners manuals warn against using any additives with alcohol in the fuel. I can see it useful in gas, but I'm still learning about diesel.
Some of those older diesel injector pumps didn't have seals which would even cope with ULSD.
I did note that ethanol gasoline blurb I read was quick to point out it contained rust inhibitors. I wondered at the time how much the comment was more about "marketing" or was it the fact that ethanol needed it.