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180 comments on DrumBeat: April 7, 2007

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Twilight on April 7, 2007 - 8:57am Permalink | Subthread | Comments top

A question on Ultra Low Sulfur Diesel - I have read comments that it has less BTU energy per unit volume (?) than the older formulation, and that it is closer to #1 diesel. Can anyone verify this? The comment I read said it was 1/4 fewer BTUs, and this would be significant. You would think it would have to increase fuel consumption if true.

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AlanfromBigEasy on April 7, 2007 - 10:06am Permalink | Subthread | Parent | Comments top

Sulfur is actually a fairly decent fuel (minor pollution problem with the exhaust, but if the price is right ...)

I am not sure which has more specific energy per volume; sulfur or diesel. but Road diesel in the US has been limited to 0.5% sulfur for over a decade. So the delta from 0.5% to 0.015% sulfur cannot be large.

The most common way to remove sulfur (AFAIK) is to bubble hydrogen through it, creating H2S (rotten egg gas). This also reacts with some few oil molecules and tends to shorten them (shorter > less dense > less energy/volume). A minor effect other than a reduction in lubrication. (#1 diesel has very low lubrication). Additives are supposed to bring the lubrication back up to "acceptable" levels.

I add a cetane improver to my 1982 M-B 240D :-) which also improves lubrication.

I could believe a 1% reduction in specific energy/volume (don't know) but not more.

Best Hopes,

Alan

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DelusionaL on April 7, 2007 - 10:47am Permalink | Subthread | Parent | Comments top

Alan, the acetane improver do you have a brand name? My r-hand man here handed me a bootle of a fuel additive that is supposed to give @20% increased fuel economy and only adds 3% to the price per gallon. I want to research this as the economics play out very well for our trucks.
I also use slick 50 oil additive which I think saved my engine during a oil loss where I had to drive 8 mi. with intermittent oil pressure.
Thanks D

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AlanfromBigEasy on April 7, 2007 - 12:43pm Permalink | Subthread | Parent | Comments top

I use by "Diesel Kleen Cetane Boost" by Power Service.

From memory, Walmart claims slightly over a 1% gain in fuel economy from diesel fuel additives. If you have a fleet, trying to talk to one of their truck manahers. etc. would be a good idea.

Checking tire pressure alos helps, as well as synthetic lubricants (everything from wheel grease to differential fluid to transmission fluid is WELL worth it given small volumes and long life. Engine oil is questionable).

Also, just cleaning dirt off and waxing helps !

Best Hopes,

Alan

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davet on April 7, 2007 - 1:04pm Permalink | Subthread | Parent | Comments top

It's actually 500 ppm (so called low sulfur diesel) or 0.05% to 15 ppm for ULSD (0.0015%). I have not noticed any mileage differences between LSD and ULSD, although I do see a ~5-6% (2-3 mpg) hit going from (U)LSD to bio. Bio has about 10% lower energy density than diesel, but significantly higher cetane and better lubricity.

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Bob G on April 7, 2007 - 1:30pm Permalink | Subthread | Parent | Comments top

Keep in mind that production of ultra-low-sulfur diesel also requires a bunch of natural gas, to produce hydrogen, to remove the sulfur. In other words, more energy invested per BTU delivered.

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180 comments on DrumBeat: April 7, 2007

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