Boiling fuel-oil

Jeff Krawic

Here is a question I have never seen the answer to! HOPE someone out here has this knowledge. I wonder if there exists a "pressure-temperature" chart that shows the boiling point of fuel-oil#2 at atmosphere, down to 29" mercury. I know I have charts for water, R-22, R-12,...(yup still have those too) etc. etc but I have yet to find one for Channel #2! (fuel-oil) Its difficult to explain to a service tech the reason his fuel oil is showing signs of air at 23" vac. on the suction side of the pump, is because the oil is boiling under the vacuum. I am dying to find charts if they exist, documenting this law of physics. Does anyone out there know of such charts???? Any help on this one would be greatly appreciated!!!!

Firedragon_4

I've seen that done at as little as 10\",

but unless you have a pump with a plastic cover it can be tough to show. I've never seen a chart either because it's not really boiling, it's hydrogenizating. That's my own word BTW, since I had a very smart chemist explain it all to me, but even he had trouble with the words.

It's the hydrogen in the fuel that's getting literally yanked out of the liquid carbon and looking like a boiling effect. Suntec, Webster, Danfoss and Carlin have some great slides that show it, but I can't remember them having charts either.

If you do come across one I'd love to get a copy. Thanks!

Carl PE

Had this same problem

Saw this on a generator install. "Custodian" tried to suck diesel from an underground tank to a day tank on the 3rd floor. Through a filter, no less.

Didn't work too well. He was convinced that all the pumps were defective because of the noise.

Moved the pump to the basement, worked great.

Never seen a chart like you're asking for. Maybe the oil company could get you one?

Jeff Krawic

hydrogenated what???? LOL

Hey George! I have seen it too with the demo and the plastic cover over the pump body. I still have to believr there are charts,......somewhere out there that document the temp vs hydrogenating effect (sp?) and if I ever DO come across them, you can COUNT on me getting the info to you! Thanks for the response. ^5 on the 3 part pump seminar you did with the magazine! It got my boss thinking!

Firedragon_4

Thank you for the kind words and if

you liked that you're gonna love the two-parter coming out on how to install an oil tank to code. I wrote this one to be a 'keeper' in the file.

Jeff Krawic

Fuel oil boiling

Carl I did try 4 of the local oil companies. 3 out of 4 had NO idea what I was even asking!!!! (laffing) The fourth said quite matter of factly that those charts do not exist. They may be right and then again,...................sees Jeff in the basement, 5 cu. ft vacuum pump running, micron gauge attached, digital thermometer in the beaker, sealed beaker that is,....... bunsen burner under the beaker,......... LOLOL........scribbling numbers on the yellow pad as change of state occurs,........... finding Jeff in next town...........or in Dans back yard,.....with da-birds......

jerry scharf

boiling #2

Jeff,

That's hard to answer without a chemical analysis of the oil in question. The main comonents of the oil will not boil, but it only takes a 10th of a percent of a lighter hydrocarbon to produce enough vapor to mess things up. I would expect more of a problem in winter, when they are thinning the fuel oil down with lighter hydorcarbons to make it flow beter.

Both the chemistry and the anecdotal reports say it will happen, but it would be hard to predict when.

If someone were to know what the "lightest" hydrocarbon that is used in the maximally thinned #2 FO, I will happily get the vapor pressure curve. Maybe someone who has friends at a refinery would know that.

sorry I couldn't help more,

jerry

Fred Harwood

Boiling #2

Heating oil is produced in big refinery stills, so it's condensing temperature and pressure are known to refinery guys. My Mark's Standard Handbook for MEs shows 2D grade fuel is distilled between 540 and 640 degrees F, which is well above its flash point, so I don't recommend that you try to boil it with an open flame.

scrook_2

an MSDS

from the oil companies will give a range of boiling points, and will give a vapor pressure at about room temperature, I believe ExxonMobil lists a vapor pressure of 0.5mmHg at 20°C (68°F), but I don't recall the boiling point range. Because it is a blend the lightest fraction will boil at the lowest temperature or highest pressure (least vacuum), once that happens you will become vaporlocked, even though most of the rest remains liquid -- the same effect as vapor lock in an older carburated car, but the car vaporlocks from high tenmperatures not high vacuums.

As for the guy trying to pull oil up several stories w/ a pump at the top: just like water, you can only pull a column of oil (or any liquid) so high, about 33 feet for water (as atmosphereic pressure is about 33.9 ft water), oil will be similar. For practical purposes the heights achieveable will be somewhat less than that.

John De Marco Jr.

fuel oil boiling

When I teach my students oil heating I tell them as a rule of thumb. Tank at or above pump suction use a single stage pump. Tank below pump suction use a two stage pump. oil pump vacuum in no case should exceed 12". That will give you almost 12 ft of lift. Single stage pumps croak at only 8 to 10" vacuum. I show my students how oil changes state with an old bell jar and a vacuum pump I found in the schools dumpster. I also teach using only single pipe systems using a Tiger loop for oil de-airation and pre heating. This way the pump only has to take from the tank what the nozzle is rated at. This gives you less sludge build up and fewer filter changes. You still install two lines, just in case of a line failure. Oil pump lift in feet = vacuum reading divided by .759
John

Cosmo_2

You hit on a good point

Why isn't every oil burner installed with a tigerloop device? If the economics is an issue, the same thing can be made with a few black iron fittings. The benefits are amazing. I have a Garber filter w/ vacumm guage and have gone 2 solid years without changing filter, still going. Of course I am too lazy to replace it I guess........

Cosmo