Need some help dewatering

[Snake]

^^^^ That pretty much sums up where I am right now.

I picked up some oil a few weeks ago that I'm pretty sure was contaminated with something. Its smelled pretty bad but at the time, I attributed it to whatever was cooked in the oil. I'm running a Frybrid still, by the way.

Throwing caution to the wind, I filled my prefilter barrel and then pumped into my water heater. Heated at 140 degrees for 4 hours and let it sit for 24 hours. I drained 4 gallons and performed a hot pan test. The oil failed. I drained another 4 gallons and did another HPT -- failed again. I let the oil sit for another 24 hours and performed another HPT. This failed too. I repeated the draining and testing until I was out of oil. The oil failed the HPT every time. I'm not talking a few bubbles -- I'm talking pops and crackles.

So I got rid of all that oil, drained and cleaned my prefilter barrel with water only, and pushed about 30 gallons of oil through the water heater. Drained all that off and everything sat for a week without any oil or water in it. Prefilter barrel was bone dry but the lines on my still had some water in them. I figured that would settle out in my next batch.

On Sunday I picked up some oil from a different source and pumped it into my water heater via the prefilter barrel. Heated again, settle for 24 hours, and performed the HPT after draining 4 gallons. More pops and crackles. Drained more, tested again. Failure. Repeated until all the oil was out of the water heater. Oil failed the HPT with pops and crackles every time.

So I tested a couple of tablespoons off the top of the 250 gallon tote that is holding the oil waiting to get processed. It was right on the borderline of passing.

Any idea what's going on and how to fix it?

Thanks in advance for the replies....

--Snake

[Clay]

Hmmm, circulate it to evenly distribute the heat, let it settle till temp is down to 100...not just 24 hours. Filter and then sample the filtered oil.

[Clay]

And tell me more about this tote? how are you getting the oil from the tote to the HWH, from the bottom or off the top?
Do you use a prefilter barrel like mine?

[Clay]

Introducing water into your system may have been a bad idea. Maytake some time to get it all out.
Take that bad oil, heat it in another container like a drum. leave it to settle for a week, come back and draw the top 3/4 off it and discard the reast. HPT that oil and then take that oil and then run it throught the HWH again for fitering.

[Hooter]

When I first got into this stuff, I was dumpster diving, and got a hold of some nasty oil. It smelled like vomit. Try as I might at filtering the oil, I could never pass the HPT. I don't know what was in that oil, but after attempting to filter it 3 times, I threw it out. The smell did get a little better, but it never smelled exactly right. I wouldn't trust it. If your method of filtering has worked up till now, it should have worked for this batch. There is something wrong with that oil IMO.

[skyskijason]

Hmmm, circulate it to evenly distribute the heat,

All this will do is 'evenly distribute' the water in the oil. A better option would be just wait another day or 3 and then drain bottom again and re-test. Still no pass, try another heat cycle. Any VO that does not get heated (ie, ALL of the VO below the heating element) will remain right there, on the bottom, after heat and settle. Just set this 'bottom' oil aside in a cubie, and you'll almost always have some seperation. Then add the 'good' oil off top of that cubie and add to next dewatering batch...

A couple things to consider:
- if the VO has any diesel or biodiesel in it, HPT does not work (the fuel evaporates giving you a potential false positive for water)
Not likely your issue, but definitely a issue w/VO from tank on truck...
- High fats oil tends to be much more difficult to dewater
- some have reported filtering VO to more than about 30 mic BEFORE dewatering actually hinders dewatering efforts
- when refining oil/gas they use rapid temp changes to help seperate liquids w/similar specific gravity - I wonder if that would help w/stubborn VO.
- mist washing can be a very effective way to dewater VO. Why? 'cause the 'free' water droplets have a tendency to 'grab' any emulsified water as they pass thru. Counter-intuitive I know, but many have reported passing HPT immeadiately after settling from mist wash. It also dramatically reduces filter usage as well, the food particles, etc tend to sink with the water droplets.

For this 'stubborn' oil, you could try mist washing a sample in 5 gal bucket. Heat 2-3 gals of oil to 140* or so, then spray the finest mist you can make over the oil. When bucket is near full, stop and let settle overnite. Pour the 'good stuff' off top and see whatcha get.

[Clay]

All this will do is 'evenly distribute' the water in the oil.

He just got done pumping the oil into the HWH and turned on the heat... circulating the oil 2 hours after pumping it in and turning on the heat is not going to re-mix it or undo any settling because non has taken place yet. I don't understand your logic here?

A better option would be just wait another day or 3 and then drain bottom again and re-test. Still no pass, try another heat cycle. Any VO that does not get heated (ie, ALL of the VO below the heating element) will remain right there, on the bottom, after heat and settle. Just set this 'bottom' oil aside in a cubie, and you'll almost always have some seperation. Then add the 'good' oil off top of that cubie and add to next dewatering batch...

that is a possiblility but a waste of time.

mist washing can be a very effective way to dewater VO.

Bad idea, he has already tryed this.

For this 'stubborn' oil, you could try mist washing a sample in 5 gal bucket. Heat 2-3 gals of oil to 140* or so, then spray the finest mist you can make over the oil. When bucket is near full, stop and let settle overnite. Pour the 'good stuff' off top and see whatcha get.

Why mess with 5 gallons, toss it.


Heat the oil, settle it longer...go 5 days, drain 5 gallons, test it. If it fails heat it to 110 and filter it. test it. If it fails i would toss it, its too wet to mess with.

[Snake]

Thanks everyone for the ideas. The old oil that smelled bad ended up in a dumpster for a renderer to deal with.

The last batch that failed the HPT is sitting in cubies behind the still and I plan on letting that sit for a while and then trying to process it again.

Last night, I put 30 gallons of oil into the still, heated it for 1.5 hours, turned the pump on for a minute to distribute the heat, and its been settling since then. I'm going to test it tomorrow evening and see how it looks.

Clay, to answer your questions, the tote I used had been pressure washed and had about a gallon of used oil in the bottom. To my knowledge, it hasn't had anything else in it since it was thoroughly cleaned prior to purchase. My setup is exactly like yours (minus the Bud Light bottle). I used a small transfer pump to get the oil from the tote to the prefilter barrel and I pulled the oil from about 4" below the surface of the oil.

I'm hoping that I just didn't give the last batch enough settling time. Its weird, but when I drain oil off the bottom of the water heater, I don't get a bunch of water initially. It all comes out looking the same and I've drained 3-4 gallons in the past and then tested what was left in the WH. I even tried changing pans this last time (just in case something weird happened to the iron skillet I was using).

I also bumped the heat setting back up in the water heater, and I half wonder if that had anything to do with it. My first batch I had it all the way up (150 degrees) and then bumped it down to 140 (verified with the temp gauge). I turned it back up for this 30 gallon batch and will keep ya'll posted on the results.

If it doesn't pass the HPT again, I'll follow your advice: " Heat the oil, settle it longer...go 5 days, drain 5 gallons, test it. If it fails heat it to 110 and filter it. test it. If it fails i would toss it, its too wet to mess with."

Again, thanks!

--Snake

[Clay]

My setup is exactly like yours (minus the Bud Light bottle).

Ah! theres the problem

[HORSEMOVER]

Add some Bud Light to your filtering process and your oil will look great in no time. Even if it doesn't you might not notice or even care:chuckles:

:cheers:

[Snake]

Awwwwww crap. I knew I was missing a step. Going out to buy some Bud Light now....

--Snake

[greasyX]

last step=hot shot of Startron,starbrite,agitate to mix this should process the last of the water into a methanol blend that you will easily burn.This is NOT an alternative to dewatering,think of it as insurance against water that "snuck" into your fuel....grease out

[lamintdog]

Take that bad oil, heat it in another container like a drum. leave it to settle for a week, come back and draw the top 3/4 off it and discard the reast. HPT that oil...

That describes my entire drum filtering process with the exception that I settle w/ heat and run it through a goldenrod prior to filling. If that sample passes (which it has done to-date) I fill 'er up.

...then take that oil and then run it throught the HWH again for fitering.

Ah, here's where your "goldenrod" equivalent is - through your bag filter... yep.


The only comment I would add here is to HPT this oil again after you filter it through the still.

If your oil passes a HPT before you added it to the still for filtering (after Clay's suggestion in the 1st quote above), and then after filtering through the HWH, you fail a HPT, then somehow, water is being introduced into your oil somewhere in the still. The 2nd HPT could help you isolate the issue...

Quick note: Everyone's results are different, and obviously the still can work well if you dial it in, but something in my frybrid still setup was causing me to get massive amounts of water in my oil... literally like it was adding water to my oil. I tested venting, settling longer, temp increases,etc but never figured it out and ended up moving to a simple barrel design (w/same oil source) which solved my issue. If you could setup a denim filtering barrel side by side, it'd be interesting to compare the results using the same bad oil... If you're like me, I'm sure you've got plenty of free time to do that (right)

[Marv]

Hmmm, circulate it to evenly distribute the heat, let it settle till temp is down to 100...not just 24 hours. Filter and then sample the filtered oil.

I agree...it takes mine about 3-4 days to cool down to 100 degrees. I had been waiting 24-36 hours, but I wasn't seeing much of a drop in temp - oil would only cool from about 148-150* to 120*.

The longer it sits, the better chance you have of getting more contaminants to settle out of the oil.