Info on Diesel Fuels

[Jimma]

So what is a person to do? Its perplexing to say the least.

 

[1983M35A2]

great thread.

 

[steelypip]

The problem is that 'sulfur' in diesel fuel and 'lead' in gasoline aren't the sulfur and lead that you're thinking of any more than air is oxygen.

Yes, many Arabian crudes are high sulfur. But pure sulfur isn't soluble in oil (or water) just as pure lead isn't soluble in gasoline.

This article discusses how to do the chemistry to get what the regulators want, and mentions a soup of sulfides, benzothiophenes, benzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) as common organosulfur constituents of the petroleum fraction we get diesel fuel from.

Now I don't know which of these compounds is a good lubricant and which isn't. Presumably a petrochemist somewhere might. But the upshot is that you'd have to take the lump of sulfur, react it with something, and then react that with something like ethane to get a methly ester. The more complicated compounds (which I suspect are what are better lubricants) probably are harder to make.

Ma nature made us a soup full of fun stuff, and it's actually pretty hard to synthesize what we get out of the ground cheaply most of the time.

What burns me about all this diesel sulfur reduction silliness is that the amount of diesel fuel burned in the developed world contributes spit to atmospheric SOx emissions compared to coal-fired powerplants.

The reason they're going after us instead of 'clean' (ha!) coal is because CONSOL and power companies can buy a lot more senatwhores than truck drivers can.

 

[4x4 Forever]

Took carbon chemistry is HS and should have paid more attention.

What your saying makes sense and I'd love to figure out more but it also sounds like $$$. My uncle made the catalyst for cracking crude but was not a petrochemist per say. Had him scratching his head and saying he would have to ask a petro guy...

Thanks for the info guys!

 

[steelypip]

As I think about the 'what to do?' question, I think the answer is pretty straightforward - spike your pump diesel with some biodiesel. That test report showed the most wear reduction from spiking ULSD with plain old biodiesel. It's cheap and can generally be found. Why mess with anything else?

 

[johnjean]

what about adding new motor oil to your diesel fuel as a lubricant

 

[frodobaggins]

what about adding new motor oil to your diesel fuel as a lubricant

Yeah it bothered me that they only tested used motor oil.

 

[steelypip]

I doubt new/used would make much difference in this application. Motor oils a) never have much in the way of EP additives anyway, b) don't have viscosity breakdown anymore until well past the change interval, and c) don't really alter chemistry in any significant way up to the change interval.

I suspect that the reason biodiesel works well is because of the film-forming qualities of vegetable oils. They're not preferred for use in conventional IC engines as a lubricant because they gum, but are key components of non-circulating and total-loss oils (which diesel engine fuel would qualify as).

In fact, up until about 1980, the gold standard of crankcase scavenged two-stroke engine oils was castor oil. It wasn't until then that something better was synthesized, and it's still probably the best corrosion preventative if you can stand the 20:1 caramel corn smell and smoke.

 

[MiSasquatch]

I had my injectors checked and tested by Superior Diesel in Detroit. He told me to save my money and put them back in just as they were. This after burning WVO during the warm months and pump diesel during the cooler/coldest months. I was concerned about what I was doing to the pump and injectors but he gave the truck a clean bill of health. So....mo WVO for the Cummins. FYI