Centrifuge on Frybrid Still

[cgoodwin]

I just mounted a DC centrifuge to the top cold water port on top my 80 gallon Frybrid Still and had some interesting issues getting it working, mostly involving the units need for a vented drain, once this was sorted out I was quite impressed with the results.

The Frybrid Still was filled and heated, then allowed to settle and the "smank" drained off. The oil was still hot, it was then cycled through the filter for a brief period to remove any particulates which might clog the jets in the centrifuge, then I powered up the centrifuge and let it run for about 30 minutes before I could no longer control myself and I spun it down and took it apart.

The results were quite encouraging, the inside of the rotor was covered with a layer about 1/8" deep of extremely fine silt, the same black silt I find when I cut my used fuel filters from my truck apart. As soon as I can get back into the shop today (child care issues) I plan to bring it back up to temp and allow it to cycle for several hours.

I will post a diagram soon.

[SunWizard]

Glad to hear you got it working. Thats an impressive amount of goo for only 30 minutes of run time. It will be interesting to hear your results of further testing.

[cgoodwin]

I had an interesting issue with the install which bothers me, I found a way to fix it and it works perfectly now, what bothers me is that i do not understand what the issue was.

The DC was screwed onto a 6" section of pipe which was in turn screwed into the could water inlet of the water heater, befoe screwing it in I looked into the hole with a flashlight, I could see all around inside the heater. When I gave pressurized oil to the DC it spun up and I could hear oil dripping into the heater for several minutes, then the dripping stopped and the centrifuge spun down quite a bit. Oil pressure held but I could feel the frequency of vibration drop. After a few minutes running like this the centrifuge would begin to make a hissing noise and vibration was almost non-existant, I assumed the rotor had stopped spinning. About that time it would again trickle oil into the heater and spool up agian. This would repeat over and over.

I decided that for some reason the centrifuge was not draining and was in fact filling with oil which prevented the rotor from spinning. I removed the 6" pipe and replaced it with 2 close nipples and a T, ran a 4" section from the side of the T to a 90 and up 8" to a hight above the centrifuge thinking that this would allow air into the drain and allow it to drain more easily. It worked. I still do not understand why this was required, the drain pipe was 3/4" pipe and could have gravity drained a horse trough!

[Pir8Darryl]

Originally Posted by cgoodwin

I still do not understand why this was required, the drain pipe was 3/4" pipe and could have gravity drained a horse trough!

Probably just some strange little quirk.

I'm sure your going to do a lot of expirementing, I'll bet your head is swimming with ideas. It will be interesting to see your results as you progress.

I personally would like to see a batch of dirty WVO run thru the CF first, then see how much gunk settles out when you run the same oil thru the still.

I'm absolutely dying to get mine set up, but the work schedule just keeps me running 24-7. I'm thinking I'll retain my mist washing and overnight settling steps, then replace the vacuum boiling with the CF. The vacuum boiling is a real pain in the butt.

Keep us all updated, and good luck!

[new2VOfuels]

I have thought of doing this exact mod to the frybrid still but i was concerned about my pump not being able to hold that high pressure that the centrifuge needs to operate ( I have the Harbor Freight pump as listed in your frybrid still instructions). As i understand it, about 70-80 psi is what it takes and the hotter the oil, the better. Also the annoying heat switch on the pump would interfear with this process.
I have a buddy who bought a DC centrifuge and he showed me how well it operates even without filtering the oil first. Dumpster oil straight to the centrifuge for maybe an hour - minus the time it took to clean the bowl a couple of times - and his oil looked like tea after going in like coffee.
I was considering replacing the X100 filter with the centrifuge so i could heat, settle, drain off the crud, then centrifuge it. or maybe even skip the settle time and be able to produce a clean batch in less than a few hours instead of over night.
Can this pump handle that pressure?

[cgoodwin]

I abandoned vacuum dewatering because it is basicly distillation which means that the water being removed is pure, ie; the water soluable compounds such as acids and salts remain in the oil rather than being removed with the water. In addition vacuum dewatering is boiling or causing a phase change in the water, this has been shown to cause hydrolysis leading to accellerated formation of polymers.

That said I have only chair tested it (sat in my cheair thinging about it).

My concept is to use the centrifuge to extend filter life and deliver a fuel easily and inexpensively which has been filtered to very low micron levels. If I process my oil as usual by filling the still, heating the oil and allowing several hours settling time, this oil is still hot and I have had very good results removing the water and the majority of the larger suspended particulate matter. If I then cycle this oil through the centrifuge for several passes to "Polish" it, I have not had to add any heat or add another complicated step to the process, I simply turn on the centrifuge and let it go for an hour.

So far this is what I have found:

Oil which had already been through the still and then cycled for some time through the filter was pumped back into the still and heated, I then cycled it through the CF for 15 minutes and found a layer of very fine black particles in the CF bowl. I cleaned it and repeated the process leaving it to cycle for an hour. The filtered oil I started with had a dark color, like maple syrup, after an hour it has the color of new oil and I removed about 1/4" of what looked like black clay from the CF. I think this is particulate matter lower than 2 microns which had remained suspended in the oil.

I also filled the still with waste oil (all my oil is of good quality with very low water levels) which I did not process through the still, instead I cycled it through the CF for 30 minutes and opened it. In the bowl I found what appeared to be tiny droplets of water in an emultion of nasty goo, very soft like snot. It wiped easily from the bowl as opposed to the clay like silt which took some muscle to remove.

I will continue with this batch and see if I can get it clean with just the CF, however I think that the use of heat settleing before CFing will speed the process & require far less work.

N2F- I did not use the low pressure pump the still uses for the CF, I have a seperate pump for it. I would like to see an electricaly driven CF as I think it would be less likely to plug a jet (none) and would remove the need to lines filled with oil pressurized to 90psi. I am considering installing a safety switch on mine so that if the oil pressure before the CF drops it will shut the pump off. The last thing i need is my shop sprayed with 80 gallons of hot oil at 90 psi...

[Brad]

Originally Posted by cgoodwin

.....then I powered up the centrifuge and let it run for about 30 minutes before I could no longer control myself and I spun it down and took it apart.

I felt the same way, I just had to check out the progress and was very pleased with the results.
The silt looks like thick dark pudding, and gives me an appetite The thing I like most is that everything is contained (though more dangorous from the pressure) and dont have to worry about anything falling in (for example).

I use the push in fittings with Insta Grip hose for the centrifuge lines. Prior to that, I had tried aluminum lines and JIC fittings, but the vibration from the gear pump just wrecked them like a toothpick home in a tornado.
Other than that, all is good...........

[Pir8Darryl]

Originally Posted by cgoodwin

I abandoned vacuum dewatering because it is basicly distillation which means that the water being removed is pure, ie; the water soluable compounds such as acids and salts remain in the oil rather than being removed with the water. In addition vacuum dewatering is boiling or causing a phase change in the water, this has been shown to cause hydrolysis leading to accellerated formation of polymers.

That said I have only chair tested it (sat in my cheair thinging about it).

The vac-boiling has been the most difficult part of my process from day one. Unfortunately, it's a nessecary evil in my circumstance due to the "on the fly" setup, the big box truck's appetite for massive quantities of fuel, and the high overall humidity level here in the ohio valley basin.

Me and you have actually had this conversation before, and the concensus was that so long as I was mist washing [at a 1:2 ratio], then overnight [heated] settling,,, the vacuum boiling was acceptable, and infact, a prudent final sfety step for my particular needs.

The problems I'v encountered with VBing, besides the massive heavy 90 gallon stainless steel tank's "white elephant" status have been vacuum pumps failing pre-maturely, air leaks, and the uneasy feelings of a 1000 pound "implosion bomb" just 2 feet from the back of my head

It sounds like your having good results..... Come to think of it, I cant remember you ever taking a difinitive stand on the mist washing issue. I'v seen you endorse it's use a time or two here on the forum, but I dont think I'v ever heard your overall viewpoints on it... Maybe I'v just missed it

So the "snotty" emulsion from the test batch, as opposed to the "hard clay" from the processed batch would seem to indicate the CF does infact have [at least some] de-watering abilities. [?]

If I can, I plan to contain my pump, CF, and ALL high pressure lines in a dome topped barrel, with baffles to keep the VO from splashing up onto it... I wonder if the top to the webber grill will be missed

What made you go with the DC over the SC?

[cgoodwin]

"What made you go with the DC over the SC?"

Someone walked into my shop and put one on the bench with the pump and asked to be a part of the co-op here. I thought I would give it a try. I also have a Spinner but the float assembly made of mild steel gave me second thoughts...

[cgoodwin]

I am sold, processed another 80 gallon batch today, the CF spun for about 2 hours and the oil went through the filter like water. Color went from maple syrup to light yellow. Had to clean the CF twice but could have likely done it once....