Lubricity of diesel

   / Lubricity of diesel #11  
I think everyone agrees, just that we all have different reasonings behind it. Removing sulfer will lower lubricity. Period. Something will need to be added to the fuel to correct for that. This will be done in the MFG process I'm sure. The fuel companies wouldnt want the responsibility of millions of diesel engines failing in this country because of the fuel they supply. The removal of the sulfer will do wonders for the atmosphere as well as the cleanliness and longevity of our diesels. Sulfer is the main enemy of a diesel engine and I believe the primary reason the American public wants to avoid the "nasty,dirty,smelly diesels".

Dont worry guys, the ULSD has been tested and is curently for sale in parts of this country, running old tractors and IDI diesels. No big deal as far as we're concerned. Not negatively anyhow. /forums/images/graemlins/grin.gif
 
   / Lubricity of diesel #12  
</font><font color="blue" class="small">( Many diesel fuels are good boundary lubricants. This is not due to the hydrocarbons that constitute the bulk of the fuel. Instead it is attributed to trace amounts of oxygen- and nitrogen-containing compounds and certain classes of aromatic compounds. Evidence for the role of trace quantities is the fact that the lubricity of a fuel can be restored with the addition of as little as 10 ppm of an additive.

Lubricity enhancing compounds are naturally present in diesel fuel derived from petroleum crude by distillation. They can be altered or changed by hydrotreating, the process used to reduce sulfur and aromatic contents. However, lowering sulfur or aromatics, per se, does not necessarily lower fuel lubricity.

The use of fuels with poor lubricity can increase fuel pump and injector wear and, at the extreme, cause catastrophic failure. Such failures occurred in Sweden in 1991, when two classes of "city" diesel with very low sulfur and aromatics contents were mandated. Heavy hydrotreating was necessary to make these fuels. The problem was solved by treating the fuel with a lubricity additive. )</font>

That is from the Chevron web site.
 
   / Lubricity of diesel #13  
I read this as saying lowering the sulfur, does not necessarily lower the fuel lubricity. In other words it may have something else in it that is lubing it, so if it does then lowering the sulfur, might not have much change in it. It would seem from what it reads it all in what other additives it might have in it. As it is talking about not just sulfur but other aromatic contents. You can't just single out one thing and say it is doing or not doing something, and that is what you are doing. For sulfur is just one of the things it is mentioning.
 
   / Lubricity of diesel #14  
I've become a believer in cetane boost also. My son has a 1987 6.9L F250 Ford. That thing would black the road with smoke when he first got it. Finally found the sweet spot of how much to raise the cetane level. Smokes very little now and picked up 2 mpg. Also use Lucas fuel treatment. That cut down on a lot of the noise from the pump. I buy the Lucas in the 4 gal. case. Use it in everything. Gas and diesel.

My fuel supplier has already mixed in additives before I get the fuel. I just like the Lucas for added protection since I saw/heard what it did to that Ford pickup.

I welcome the new low sulfur fuel. One of my tractors meets the new emissions standard. Once the new fuel is on the market I can go 300 hrs. on an oil change then.
 
   / Lubricity of diesel #15  
</font><font color="blue" class="small">( Lubricity in a conventional diesel fuel is derived by the presence of polar molecules (including hydrocarbon-based and sulphur-based compounds). As GTL Fuel is essentially sulphur-free, and since the SPD product work-up process involves a hydroprocessing step which removes polar molecules, neat GTL Fuel displays poorer lubricity properties than crude oil derived diesel fuels. This is also the case with most other highly hydrotreated, very low sulphur diesel fuels.
)</font>

Egon /forums/images/graemlins/grin.gif
 
   / Lubricity of diesel #16  
Sulfur is just a bad contaminant of crude oil, not a lubricant.

The more contaminating sulfur in the crude oil the less you can sell it for because it costs money to remove it, good high grade crude oil is low in sulfur contamination and costs the most.

Sulfur has no lubrication value whatsoever, zero, which is why no one ever adds sulfur to increase lubricity, instead they add lubricating molecules like fatty acid methyl esters or some aromatics.

Sulfur is removed by hydrogentation of the raw crude oil, adding hydrogen to it turns it into a real nasty toxic gas that then is removed from the refinery stream.

Sulfur stinks.

Good riddance to sulfur from gasoline and diesel fuels! /forums/images/graemlins/grin.gif
 
   / Lubricity of diesel #17  
Skypup; read the post again. You may note that when sulfur is removed some of the lubricating agents it is chemically combined with are also removed.

By the way; forms of sulphur are added to the methane gas or propane your furnce burns. /forums/images/graemlins/grin.gif

Egon
 
   / Lubricity of diesel #18  
If he had earned advanced degrees in chemistry, and his work/hobby was the study of diesel fuels, and biodiesel fuels, I would be more inclined to believe the Ag engineer. Not to dispute his concerned point about the "cleaner" diesel fuel. I'm more inclined to believe Skypup, although I do add power service product to my diesel fuel, mostly for lowering the pour points, and keeping any possible moisture from damaging my fuel system. Any additional lube will be welcome. Interesting about the removal of some lube properties during the lowering the sulfur for the newer fuel.
 
   / Lubricity of diesel #19  
Don't take my word or anyone elses. But give Stanadyne a call. They are one of the leading mfg. of pumps, injectors, etc. for diesel engines. They have more phd's and engineers working for them than you'd care to count. Ask what they think about lubrication of the fuel not being an issue. It's a huge issue and not having it will lead to premature failure of pumps and injectors. And yes removing sulfur does remove the lubricication values of the fuel. No it's not the sulfur that lubricates but the properties that are removed with sulfur that contributes to the lubrication value of the fuel.
 
   / Lubricity of diesel #20  
Egon,
I believe the sulfer is added for the odor, similar to ethyl mercaptan. Propane has no natural odor, therfore a smell must be added to give warning in the occurance of a leak.
 
 
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