hpt mystery? ?

[SHERMAN7]

Tried cold upflow failed hpt. 2nd idea let upflow fill 30g barrel heat and settle overnight failed again. Here's what's happening heat teflon hotplate to 320 deg small spot of oil tons of Verry small bubbles cover bottom have to slide it around to get them out. Used new vo no bubbles. Residual oil in pan smokes before 320. Is pan too hot? Teflon creating false result? Something in oil that isn't water.
Also there is no visable water. Some of this has settled in barrels (plastic) for 2 months. Comes from 4 places 2 china 2 italian. Trying 1 barrel with salt and bs right now.
any suggestions on on hpt procedures.
Also weather is 70-90 in the day 60-70 at night. And Verry humid.its all stored in shed out of sunlight gets real warm in there.

[Bluebird]

Hello Sherman, what part of the country are you in? Newshop2 had a similar situation with the HPT and started vacume dewatering his oil and no more HPT failures, but he now has other issues i.e. paint or varnish smell when cold but BurgerKing smell when hot?

[SHERMAN7]

Sc on the coast Verry hot and humid here now. Im wondering if bubbles are from sauces or batters that went in with the food. No bad odors just smells like a kitchen exhaust fan output.

[HoldOnTight]

Originally Posted by Bluebird

Hello Sherman, what part of the country are you in? Newshop2 had a similar situation with the HPT and started vacume dewatering his oil and no more HPT failures, but he now has other issues i.e. paint or varnish smell when cold but BurgerKing smell when hot?

Sounds like Newshop2 had oil with high FFAs to start. Dewatering was working for him.

My guess is that you aren't allowing enough time for settling or flow is too high, so you are taking out oil "before it has fully cooked"

[mankypro]

I do hpt's at 400f in a tabletop electric teflon coated pan I use about 1/4 cup oil processed oil.

That said I've seen virgin oil fail hpt - I have 5 gallons of it right now waiting to be cf'd.

[HoldOnTight]

Oil that is not used, will generally have lower FFAs and so I'm not too surprised it fails the HPT. The HPT is inaccurate when FFA levels are higher. Sunwizard has proven this.

Oil that is high in FFAs has a higher capacity to hold "dissolved" water. So while virgin oil may be saturated at 500 ppm of water, the same stock of used oil with high FFAs can hold over 1000 ppm of dissolved water.

This means the oil that failed the HPT could be left in the container to age (FFAs increase) and later it will pass the HPT when the FFAs are high enough. The free water in the oil, if not too much, could dissolve in the oil as it ages. Either way, the water in the oil can cause some issues (e.g. corrosion of steel...).

[drboost]

I can't afford a Sandy Brea (SP?) test so I HPT. I use a cast iron skillet heated to 350. I almost never get failed results. I was worried so I took a sample, put a drop or two in it, shook it up like crazy and it failed like crazy. That made me feel better. I though 350 was the correct temp??

[HoldOnTight]

350 or 400F aren't all that much different. I think either will work but you might get false positives for some contaminants. Remember that pure water boils to steam at 212F at sea level and at cooler temps at high altitudes. Here you will find a pressure, volume, temperature diagram (3D depiction) and a big colorful volume, temperature diagram (sea level is assumed and a constant) for pure water:

http://en.wikipedia.org/wiki/Phase_diagram

If you want to detect water, 350F is certainly hot enough to show if any dissolved water is present...even if contaminated...350 will allow any water to go directly to vapor. At temperatures higher than 400, other contaminants could also go to vapor and give a bubbling indication even if there may or may not be water present. Other contaminants might include residual oil additives (e.g. motor oil) from that re-used container you put some WVO into or God knows what source...

A teflon coated pan may not have the same level of heat energy in it as does iron, so the pan may cool too quickly and not provide enough energy to make water go to steam quickly if the pan is not made of iron as a base metal. Search on "specific heat" for the metal you are using and thickness counts, as well as coatings that could resist heat transfer. Using teflon coated pans, whether a skillet or not introduces variability in the test and the measurement results.

[inconu]

The carbide manometer test is way more accurate and repeatable than the HPT.
I get consistent results and it's quantitative not just pass-fail. Easier and safer too.
http://make-biodiesel.org/Quality-Te...m-carbide.html