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UPFLOW SETTLING - DEWATERING: Simple VO cleaning system
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Dry fuel is the single most important factor for successful long term operation of any diesel fuel engine or turbine. Vegetable oil, and especially the contaminants in used VO absorb and retain moisture/water. If one takes a well mixed sample of used VO one will very likely find enough moisture present to show on a hot pan test. If one then chills the used VO and lets it settle so the water absorbing contaminants [animal fats, trans-fats, saturated fats, hydrogenated oil, food particles, burnt bits, etc] fall out of the mix, then HP tests the two fractions, where would you guess most of the moisture is?

I use cold upflow settling to remove all those contaminants listed above, along with all the water which will react to a HPT. Clear, dry, clean VO with NO contaminants gives the fewest problems when used as diesel fuel, regardless if its being used as 100%SVO, blended VO-ULSD mixes, or transmogrified into biodiesel.

Plant oils are generally too viscous to be used directly in diesel engines unless the ambient temperature is above ~80°F, and even then only in some of the more simple mechanically controlled engines. To use veg oil in all engines in temperatures below 80°F the viscosity must be reduced.
Three methods are generally used to lower the viscosity:
1-Convert the oil chemically to biodiesel,
2-Heat the fuel system to above 80°F and the oil to >150°F before the IP,
3-Dilute the oil with solvents, after removing the oils and fats that separate out below 80°F.

Older simpler engines in warm climates where it never freezes are much more tolerant to fuel contaminated with water and other stuff. Modern engines operating in frigid climates are very sensitive to contaminated diesel fuel. Pilots in the north always drain samples from the bottom of every fuel tank and visually inspect the sample for any cloudiness indicating moisture or other contamination, before taking off. Where they work there is no margin for error.

This drawing shows a simple VO cleaning system.

http://www.frybrid.com/forum/attachment.php?attachmenti...9&stc=1&d=1193006636

The processor consists of a 10 gallon barrel with the bottom cut out, and mounted open bottom up bung-to-bung with a 2" close nipple onto a vertical 55 gallon settling barrel. A 2ft piece of 2" exhaust pipe with the top end flared, sits inside the nipple coupling and ensures that the new oil is delivered near the bottom of the settling barrel. Steel pipe is rated by inside diameter and exhaust tube is rated by outside diameter, thus they fit well together.

Primary filtration is through bugscreen and pantyhose on a simple 2x2 wood frame that sits on the rim of the 10 gallon 'funnel'. The oil settles in the barrel and every time I add oil into the settling barrel, clear oil is forced out of the 3/4" bung through a street elbow, a hose bib valve and through a clear vinyl tube to the canvas bag 'jeans leg' ~ 20 micron bag filter assembly, into the final filter barrel. I find that the 30 gal poly barrels are more convenient for the 2nd stage, and use two of them as collection/final filtering barrels.

For making biodiesel, the oil off the top of the first barrel is ready for processing.

Final filtration is by rotary hand pump, through a whole house filter assembly with a 5µ filter cartridge. The barrel pump I use is a rotating-vane, positive-displacement, self-priming type which can pull or push equally well. The 2nd barrel can be heated or the VO diluted with ULSD or kerosene, to make final filtering easier.

This system works best with no heat at temperatures below 65°F to remove saturated fats and hydrogenated oil, or low power [less than 100W] evenly distributed heat if one wants to keep them in the mix. If one does a hot pan test on the oil in a cubie, one will discover that as one goes deeper in the cubie the amount of moisture increases. In my experience most of the moisture is in the sludgy emulsion of animal fats, hydrogenated oil, and food particles in the bottom layer. Since this is the stuff that causes most of the problems with cold blend fuel systems, I use the unheated upflow settling to separate and remove the troublesome sludge and the moisture it contains.

The canola oil I use is clear and reasonably dry to start with, hasn't been mixed with animal fats, and my supplier puts it back into sealed cubies while it's still warm. The cubies sometimes settle for months and I decant the clearest portion off the top into the processor. A cubie spout makes it easier. I pour a bucket or cubie of oil into the 10 gallon barrel and let it do it's thing. The oil that comes off the top of the primary filtering settling barrel is not wet.

This VO cleaning system is based on the simple principle that water, wet oil, fats, and most other contaminants are heavier than clear dry oil. Suspended water and oil bonded with suspended water is heavier than clear dry oil, therefore it will not float to the top. Because the 'new' oil is placed at the bottom, any water, wet oil or food particles will NOT float to the top if the oil is not heated. If there are no convection currents to mix the oil then the clear dry oil comes to the top and the contaminants stay on the bottom. This cleaning process is called "Upflow Settling". This first stage gets VO so clean that very little builds up in the bag filter and the cartridge filter is good for hundreds of gallons.

Observations indicate that a couple of material properties make upflow separation work. Water molecules are more likely to be attracted to, and bond with, other water molecules, food particles and hydrogenated oils and fats, rather than bond to clear dry oil molecules. Because these contaminants are all heavier than clear dry oil, they fall to the bottom of the barrel. The 2" drop tube introduces the newest oil into the bottom 1/3 of the barrel, this gives any moisture laden particles and entrained water the opportunity to bond with the sludge. Without the drop tube the system won't work. The other factor is that the clear dry oil molecules are the lightest substances in the whole mix, and if the mix is introduced near the bottom, only the lightest molecules will float to the top. The water, moisture, entrained water, dissolved water,suspended water,...a.k.a. whatever, stays at the bottom if there are no convection currents, because it is heavier than clear dry oil. With time, water molecules, free or attached find other water molecules and bond, this process eventually makes drops of water large enough to sink to the bottom.

The slow rate of new oil introduced is controlled by the valve on the clear oil output tube to about 10gal/hr. No modifications to the 2" x 2' dip tube required. The valve can be adjusted so the oil is introduced slowly to reduce any turbulence mixing the sludge in the bottom 1/4 of the barrel. Only clear dry oil comes off the top, it couldn't be easier.

In this cold climate I don't use solid oil for motor fuel, at any time of the year. This settling process removes it as a fuel system contaminant. The thick, wet sludge is occasionally pumped off the bottom of the barrel and mixed with sawdust for woodstove fuel. That sludge is a valuable resource for me, when mixed with sawdust from chainsawing fuel wood and packed into 1/2 gallon [2 Liter] milk cartons. One of those on a wood fire first thing in the morning quickly warms the house right up to comfortable temperature, especially when it's 30 below. There's a lot of BTUs in a half gallon of transfat oil/fat soaked sawdust.

Cold processing is more effective with reasonably clear used oils that don't have a lot of hydrogenated oil and fats, and may not work with all oils. The sort of wet, goat-vomit, grey-mayonaise, hydrogenated crap that some have to contend with probably won't come out much cleaner. Cold Upflow Settling basically separates heavier crud from clear oil.

The processor is in an 8 x 8 unheated shelter tent. The processing for winter oil 50VO/50ULSD base mix is done by freeze-up in late October. Even when it's below freezing the system will work to about 0°F to process clear liquid canola. No added heat, just gravity. The system has been producing clear clean dry oil for more than two years, used for diesel fuel mixes in temperatures to 30 below, on a few vehicles, with about 40,ooo km total so far and no problems or anomalies whatsoever.

This is the simplest system that requires no electricity. It can be easily assembled with a few commonly available materials. For those who want more, it can be expanded easily with additional barrels and a small electric transfer pump.

It won't produce huge volumes quickly, but it can be up and running for less than $100 while you design, develop and assemble your Ultimate-SuperMega-HyperspaceCentrifuge-VO Processor.

The basic principle of upflow settling can be successfully incorporated into other cleaning systems..

This message has been edited. Last edited by: john galt,



 
Location: coldest N.America | Registered: May 03, 2005Reply With QuoteReport This Post
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How does the oil get transferred from the 55 gal drum to the 20u filter bag?


______________________________________
'97 Ford F-350 7.3L PSD - Plant Drive kit
'84 Mercedes Euro 300D NA - Custom two-tank
Running on
vegoil and biodiesel since May 2006

 
Location: SF Bay Area | Registered: February 14, 2003Reply With QuoteReport This Post
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Thanks for the drawing. Are you using the pressure from the oil added at the top to push the top layer of the settled oil from the 55 gallon drum thru the shorter tube and into the bag filter?

How long does the oil sit in the drum and does this do an adequate job of removing suspended water, without heating the oil?

Thanks
George
 
Location: Maryland | Registered: April 18, 2007Reply With QuoteReport This Post
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I have yet to collect all the parts for my dewatering/filtering system, so your post is good timing for me. Its impressive that you are doing this in the "frozen North", but is your setup in a heated garage? Also, did you build a frame for the bug screen? If you can give me a link for the bag and cartridge filters that would be really appreciated.
 
Registered: June 11, 2006Reply With QuoteReport This Post
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looks like my setup, except I have two settling tanks.


jake
----------------------------
'99 Benz e300d (SVO conversion underway)
'87 Samurai LWB - parts hauler & mule (ACME VW diesel kit, HoH, Pollak)
***Garage full of VW 1.6 + 1.9 bits... for sale!***
 
Location: saint john, nb, canada | Registered: February 03, 2003Reply With QuoteReport This Post
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I had a setup for filtering biodiesel with a barrel pump pushing through a 5u house water filter. It was very hard to push through the filter. I always thought this was because the barrel pump was designed to pull vs push.

So just to make sure...it's possible to push thru filters with the barrel pumps?

I'm using the cheap Harbor Freight style.


--------------
'89 7.3L IDI International Blue Bird short bus

VO system: 25gal plastic tank > homemade heated pickup > Webb 525 coolant-heated 30 u pre-filter > aluminum TIH > manual valves > Walbro FRB-13 lift pump > 2u coolant-wrapped filter > 30 pl FPHE > IP
 
Location: south-central wi | Registered: September 26, 2006Reply With QuoteReport This Post



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My experience is that de-watering occurs more readily if particles have been removed from the WVO. IN your system, it appears that the oil is coarse filtered prior to dewatering, but I would question this logic as water tends to bond with particles in the VO. Why not dewater in the second barrel after the oil has been filtered?

Also, why would you not use a finer sock filter that 20 micron? My setup is almost identical but I use 5 micron filter bags into the barrel, then de-water, then pump through a 5-10 micron filter with a barrel pump.

That 5 micron polishing filter would plug pretty quick if the oil is only filtered to 20 microns into the barrel. Also, micron ratings are only good for filter bags that are contained in a housing. Hanging filters stretches them, especially if the oil is heated at all. so your 20 micron bag may be more like 30 or 40.

Are you using the clean VO for blending? WHy not save the fats and use them for fuel? How often do you need to clean the settling barrel to remove the fats, dirty/watery oil and sediments?


98 Jetta TDI with aluminim tank HotFox fuel pickup, HOH, FPHE, Coolant Heated VW Oil Cooler Filter,VegTherm, Injector Line Heaters, 6 port Pollak, and 3 port Pollak for Backflushing veg. filter
100,000 grease miles
B100 - B20 Main Tank Fuel depending on outdoor temps. SOLD

81 Benz 240D 3 Gallon purge fuel tank, Heated Pickup Stock Tank, 12V pump, HOH, Coolant Heated Filter, 16 Plate FPHE, Injector Line Heaters, 2 Greasecar Valves, Looped on Veg., Return to tank diesel.and Injector overflow return to veg. tank

91 Dodge Cummins

2010 VW TDI Sportwagon
 
Location: Vergennes, VT USA | Registered: May 16, 2003Reply With QuoteReport This Post
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quote:
Originally posted by green bus:
So just to make sure...it's possible to push thru filters with the barrel pumps?


All pumps push better than they pull.


YVORMV - Your veg. oil results may vary, see www.burnveg.com/forum
95 Dodge Cummins 4x4 +87 300TD wagon Running on 2 tank WVO, 81 Mercedes 300D on V80/D20 blend
Low fossil house- 100% solar/wind power, 90% solar heated.
 
Location: N. Colorado | Registered: August 31, 2006Reply With QuoteReport This Post
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John Galt says:

"Any necessary dewatering occurs in the first barrel, the oil comes out dry. Any water, wet oil or food particles will NOT float to the top if the oil is not heated."

Oh, how scientific of you. How do you know the oil is "dry" when it leaves the first barrel? Sure, free water will settle to the bottom, but what about suspended water?

"It does not, the first stage gets it so clean that very little builds up in the bag filter and the cartridge filter is good for hundreds of gallons."

Especially if you add kerosene to thin the oil. What if one does not want to add a thinning solvent to their WVO?

"I appreciate the thoughtful input, however this is not some theoretical filtering system that might not work. I've been using it for two years now to produce clean dry oil."

You have been using it with the oil you collect and then thin with kerosene. Seems like other users may have a completely different experience with this design. Minimal filtering prior to dewatering won't allow for proper dewatering in my experience, but perhaps the oil you collect is dry already. And I think you should clarify that you have been "using it for two years now to produce clean dry oil" cut with kerosene, which is completely different that WVO. Folks that merely want dry clean VO may want to consider modifying your system or using a different design.


98 Jetta TDI with aluminim tank HotFox fuel pickup, HOH, FPHE, Coolant Heated VW Oil Cooler Filter,VegTherm, Injector Line Heaters, 6 port Pollak, and 3 port Pollak for Backflushing veg. filter
100,000 grease miles
B100 - B20 Main Tank Fuel depending on outdoor temps. SOLD

81 Benz 240D 3 Gallon purge fuel tank, Heated Pickup Stock Tank, 12V pump, HOH, Coolant Heated Filter, 16 Plate FPHE, Injector Line Heaters, 2 Greasecar Valves, Looped on Veg., Return to tank diesel.and Injector overflow return to veg. tank

91 Dodge Cummins

2010 VW TDI Sportwagon
 
Location: Vergennes, VT USA | Registered: May 16, 2003Reply With QuoteReport This Post
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Have you tested for water with a pan test?


1985 Mercedes 300D, sold, Heat exchanger and injector line heaters, all single tank. 1997 E300D Benz ... biodiesel.
 
Location: Cocoa Beach FL | Registered: September 12, 2005Reply With QuoteReport This Post
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Not that I know of, I was just wondering if you tested. If you are getting good results, I may set my system up like yours, instead of heating to dewater.


1985 Mercedes 300D, sold, Heat exchanger and injector line heaters, all single tank. 1997 E300D Benz ... biodiesel.
 
Location: Cocoa Beach FL | Registered: September 12, 2005Reply With QuoteReport This Post
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Hey BK. I had a similar system to his in my shop. Since I moved it I am using 2 totes and a bug screen. I pump from the first tote to the second tote and after 2 weeks I pump into a 55 gal steel drum and then heat. I will tell you that with the added heat I am able to filter thru a 5 micron then a 1 micron filter bag and have not seen any crud in the filter bags. Even down here the heat I feel does the better job. The 300 now has 8000 with no filter change. The Ford filled the filter with the grey crud from the startron. When I just settled I never had this ki9nd of sucess.
 
Location: So Florida | Registered: August 31, 2005Reply With QuoteReport This Post



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With even heat and good insulation this method will work with any oil. I used this method 20 years ago with solid animal fat shortening that I had to get out of the grease dumpster with a shovel.


Ron
'85 300D
'83 300D
Since '80 former WVO conversions:
'83 240D
'80 Audi 4000D
'83 Isuzu Pup
'86 Golf
'76 Honda Civic with Kubota engine
Several generators
Kubota Tractor
 
Location: NY | Registered: November 02, 2005Reply With QuoteReport This Post
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Well, I limit my oil sources to non-hydrogenated clear oil. Plus, this is FL. Oil is never solid here.


1985 Mercedes 300D, sold, Heat exchanger and injector line heaters, all single tank. 1997 E300D Benz ... biodiesel.
 
Location: Cocoa Beach FL | Registered: September 12, 2005Reply With QuoteReport This Post
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quote:
Originally posted by john galt:
This may not work with all oils. The sort of wet, goat-vomit, grey-mayonaise, hydrogenated crap that some have to contend with probably won't come out much cleaner.

John, your system works. What I see in your set-up is similar to a 2-3 septic tank set-up on a septic system. First tank catches & settles tu**s & crud, next tank settles & catches more, etc.

What I've seen round here is winder screen straining, then hanging bluejeans, first. 1-2 pair used in series, then your settling barrels & filters type system last.
This (Jeans)seems to work better for what I call "seasonal" filtering also. Warmer summer ambient temps. yield oil somewhat closer for better summertime use....& usually the narley gravies, Crisco, & pig snott can be dumped...or whatever.

Wintertime jean use before barrell settling set-up....well one's own personal decision as to whether the heavier Crisco & pig snott should be dumped or stored for refiltering again in warmer ambient seasons, is one's own decision.

Either way, a similar set-up to your's has been working great round here for few yrs.

SmileAnd as Forest Gump says "And that's all I got to say bout that!"
 
Location: Hi in the Cascades | Registered: August 30, 2005Reply With QuoteReport This Post
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When I get solid or wet oil; either white or fails the pan test miserably, I do a heat and settle. This method can save me hours of centrifuging, or many clogged filters. The gravity method is not good for the northern Canadian climate, unless you make it a summer system.
 
Registered: August 24, 2007Reply With QuoteReport This Post
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I like the concept of this idea and think I'll give it a try on my water heater settling tank. Atm I use this in batch mode but find that even with draining small amounts of crap from the very bottom and using the tap above to take the oil from, it still takes what I consider to be too long for the oil to settle.

I'll try this idea by pumping 25L lots into the 250L tank from the bottom up and tapping the oil off from the top. This way I'll still be able to drain the crap out at regular intervals as well. I have fitted a sight tube to the side of the tank and it is nice and tall so I should be able to easily see the good oil from that which still needs longer to settle.

In my observations, oil that does get some heat from the sun tends to settle quite quickly. I left some oil I collected in some clear drums last week and today they had such a definition line between the fat I pumped the drums from the top to get rid of a lot of fats to start with.

As my settling tank sits in the sun and I can see the clear oil at the top long before all the crap is settled out at the bottom, I think the bit of heating from the sun will help speed the settling process.

I do have severe reservations about the settling removing suspended water. If all the oil has the same amount of suspended water, then no oil is going to be heavier or lighter than any other so it will not precipitate out, rather just stay suspended. I have collected oil from a lot of different sources now and am yet to find any oil that will pass a hot pan straight off. I came close this week, I think the oil was the run off from some mega salad dressing but it still was not what comes out of my drying tank nor would pass my standards as dry in a hot pan test.

I have settled oil conventionally in 200L drums and even after 4 months over the summer, I have still found the oil to be wet according to a hot pan.

For me, water is not an issue because I dry everything as a matter of course anyhow but the removal of fats and particles would make this system a worthwhile initial pre-treatment part of my oil preparation process.
 
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the great value of this type of method is that you are drawing off the VERY TOP of the settling tank
you can certainly be assured that this oil will be the driest and cleanest oil in the tank IF you are NOT heating
(that does NOT mean that it will definitely be dry and clean, just that it will be MORE dry and more clean than any of the rest of the stuff in the tank)

as John Galt says, this works with good oil

if you are using dirtier, wetter stuff than he gets, and want to do this with heat, it would be very important that your heating system be gentle and homogeneous i.e. NOT a point-source like a hot water heating element, but a big warm enveloping source, like multiple wraps of hot water tubing around the whole tank
and NO heat on the bottom (!)
and INSULATE

or
use the sun (if that's an option)

the point is not to stir things up
uneven or aggressive heating will stir things up (through convection)
and then this method will not work


rOLf

2 yrs and 100k mi on WVO - '93 VW EuroVan 2-tank w/ tank heat/HOH/10-micron heated Fleetguard, FPHE
 
Location: NE USA | Registered: April 09, 2005Reply With QuoteReport This Post



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John, I appreciate settling time depends on how often oils are added. If we assume oil is added each week what would be the required settling time? I'm trying to determine what throughput this system can acheieve . . . as I see it the total system capacity is 85 galls - if one were to draw 20 galls per week the oldest oil in the drum would be about 4 weeks old. Is this sufficient time for settling?
 
Location: Scotland UK (Sun-Thur), England UK (Thur-Sun) | Registered: October 08, 2007Reply With QuoteReport This Post
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If there is suspended water in the oil, settling must be done with heat to remove that water. Very little suspended water will be removed without heat.

If you want to use the fats and hydrogenated oil as fuel, you only need one (heated) upflow settling tank. If you want to seperate the fats and hydrogenated oils, you will need two upflow settling tanks, the first one unheated and the second one heated.

Thruput depends on oil quality, total capacity, how little the added oil disturbs the oil already in the settling tank, temperature and evenness of temperature.

With a 55 gallon settling tank, 110F VERY even heat and very good insulation, a diffuser on the oil inlet, and a restrictor on incomming oil to limit to 5 gallons/hour I can dump in 5 gallons a day every day forever and get 5 gallons of good dry oil out. I have dumped in 20 gallons in the same day a few times and 15 gallons a day for 3 days without much noticable increase in tiny bubbles in the pan test in the following days. Most of the time the water level is zero bubbles. Every once in a while maybe one or two tiny bubbles per square inch.

I am using only one settling tank because I burn the fats too. I do not let the oil settle in the 5 gallon containers that I get the oil in. I do not filter in stages. I filter thru a 2 micron Racor 1000 element and it lasts me about a year.

Direct solar heat was not very effective because the oil on the side that was hit by the sun flowed up and back down the dark side with convection currents preventing the suspended water from settling.

By the way, I do heat my filter housing. I heat it to over 120F and don't bother with evenness of heat in the housing since I am only trying to allow easier flow thru the filter.


Ron
'85 300D
'83 300D
Since '80 former WVO conversions:
'83 240D
'80 Audi 4000D
'83 Isuzu Pup
'86 Golf
'76 Honda Civic with Kubota engine
Several generators
Kubota Tractor
 
Location: NY | Registered: November 02, 2005Reply With QuoteReport This Post
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