Diesel Fuel, an explanation

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.

Why would anybody not believe this. Sounds straight forward to me. Something they may have left out is that the percentage of all the different fuels that come from a barrel of crude are not infinitely flexable. You may not be able to double the amount of one type of fuel refined or make it all gasoline. Compared to Europe we use much much more gasoline and they use about 1/2 diesel for on the road use for cars. Soon we will use much more diesel for cars as we follow Europe in this trend. I think they use UULSD ( note the two " U " s* ) that is much more " green ". Our cars have not been upgraded in design to burn UULSD but when they are diesel cars should be much more common. This should result in a much increased demand for diesel fuel here in the US*and assuming we*CAN get the much higher percentage of diesel from a barrel of crude the cost of refining may be higher ( or much higher ) so diesel fuel for our boats may go up beyond the increase in the price of crude. My wife thinks the oil companies are just gougeing us every summer and of course I tell her about supply and demand but she just dosn't buy it " there just out to get us " she says. Supply and demand effects everything with a price .. it's a fact of life. Perhaps this is what you were refering to Ken .. about believing your download. Some of my numbers are probably wrong but the jist of what I'm saying here is probably right. Please correct me so we can get closser to the truth. Us Sagitarins are always searching for the truth .. or so they say.

Eric Henning
When I was in the fuel retail business I always found it odd that the refineries shut down production of diesel for maintenance every year just before the heating season. Then, they shut down and did maintenance for gasoline just prior to the summer driving season. Of course when one refiner or several were shut down the price would spike up because supply was affected. Are they gouging? Or just making sure the investors get top return from their investment? They certainly could reverse the maintenance schedule and stop the peaks, but why?

And I think you're right on the money that only so much of each product is available from each barrel. With the ULSD and UULSD the percentage of product is going down per unit. So, I'm sure we will see a continued increase in the gap between gasoline and diesel.

While you can tailor your cracking process to produce a little different stream, e.g., a bit more diesel or gasoline, it's not totally flexible. I used to work for Akzo, and we made catalysts for the cracking units that separate the streams into the various products. You wouldn't believe how different every single one is... we custom made catalysts not only for every refinery, but every cat cracker and then basing on the infinte variety of feedstocks. It's like being a gourmet chef with ingredients that are never the same.

As far as the ULSDs, the cost comes in from additional refining steps, like hydrotreating (we also made the catalysts for that).

Right now, the price of diesel at the pumps (road) is almost $1.00/gallon higher than gasoline. I guess if they say it's high demand for diesel worldwide, I can buy that. But with that in mind, should we really be thinking about switching more vehicles to diesel?? Of course, gas will shoot back up there someday.

Oh yea, as far as maintenance... My dad was an operator at Gulf (now Chevron - bastards) and my best friend is as well nowadays. Growing up in the refinery center of Texas and still living in one (Port Arthur, Houston) I can tell you that a true scheduled maintenance shutdown is pretty rare. They basically run the h-ll out of the units until something breaks down to where they just can't run, then they scramble like hell to do ALL the stuff at once. The downstream guys just aren't that profitable, believe it or not, and they try to skin the buffalo before they turn loose of the nickel. Witness some of the big explosions around here in the last few years... a couple at Amoco Texas City come to mind.

-- Edited by Keith at 05:05, 2008-12-07

I knew there would be some expertise about refining and fuel with all you guys from the gulf. The diesel in Europe must be cost effective as the reason for it's use is economy .. I think. So if they can do it we should be able do same. What do you suppose it costs to make ULSD and how much more for the UULSD? I think it's the UU that makes it green enough to be able to be used extensivly. Who knows about this stuff. Can we use UULSD in our old engines like the British Fords and Perkins? What makes a Tier II engine anyway. If we use outboard engine oil in our low sulpher fuels for upper cylinder lube will it do any good, or harm. I know guys that use Marvel Mystery oil. Do additives cause trouble for injectors or seals? We may need to know some of this stuff sooner rather than later.

Eric Henning
Pure conjecture on my part (from having gone through the same thing with vehicles in the mid 1990s):

If you've had your injection pump overhauled within the last 10 years or so, I'll bet you'll be fine. *I'm guessing that across-the-board, all of the companies supplying parts for pump overhauls had to address the changeover from high to low sulphur fuel.

In California, the changeover happened in 1995.* I had two diesel vehicles (Ford & VW), and within six months, both started losing prime on their injector pumps (Stanadyne and Bosch respectively).* Both were overhauled and updated seals put in.* Last I knew, the VW was still going strong in '02, and I drove the Ford yesterday - so I think however they modified the seals worked.

I doubt there's much difference in mechanical performance between low sulphur diesel, ULSD, and UULSD.* The high-to-low change was (if I remember correctly) from thousands to hundreds of ppm of sulphur - so it was already down to 10% of what it originally was.* The U and UU fuels are to make the urea-injection systems for the catalysts work (can the chemists here confirm??).

When the changeover happens in marine fuel, if you haven't had the injection pump(s) overhauled in the last decade, it might be a good time to think about doing so.
I just know enough to be dangerous!
The question about using ULSD and UULSD is moot... you'll get it and (they tell you) you'll like it. On the advice of Bob Smith, I add 1 qt. of Marvel Mystery oil / 100 gallons of diesel for my Lehman 135. Others don't, and will call it "mouse milk" and imply that I'm stupid for using it. (You know who you are....) I also use Startron to treat the fuel. No problems after using both for 7 years.

I have no actual cost data for making the cleaner stuff, just know that it takes more treatment.
The primary cost - 60 to 70% - of fuel in Europe is taxes. Most Euro countries charge less tax on diesel to make in competitive. The last time* I filled up in Europe the road cost was about $1.75/liter for gas and a bit less for diesel.*
Top Bottom