BurnVeg.com Forums

[John Galt]

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 ambient temperatures below 80°F the viscosity must be reduced.

One of three methods is generally used to lower the viscosity for trouble free operation at normal engine temperatures:
1-Convert the oil chemically to biodiesel, using alcohol and caustic to remove the thicker glycerin component.
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 first removing the oils and fats that separate out below 80°F.

Most combustion chamber deposits occur with cold engines at start-up with any fuel. The important point is to completely burn the VegOil. The greatest amount of pollution and damage will occur with high percent blends of cold VO fuel in cold engines. Cold starts can form excessive deposits and produce toxic emissions. Both the engine and the environment are potentially harmed. Engine pre-heating and fuel system heating can both contribute to more complete VO combustion with VO blends or V100 a.k.a. "SVO". Prewarming the engine to 68°F can reduce harmful engine deposits, especially with VO fuels.

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?attachmentid=2119&stc=1&d=1193006636

The upflow processor consists of a vertical 55 gallon settling barrel with a short piece of 2" pipe in the bung hole connecting with the bung hole in an inverted 10 gallon barrel. The 10 gal barrel has the bottom cut out to form an input 'funnel'. A 2ft piece of 2" exhaust pipe with the top end flared, sits inside the 2" pipe 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 on a simple 2x2 wood frame that sits on the rim of the 10 gallon 'funnel'. A plastic bucket with holes around the bottom circumference has a plastic mesh bag [from citrus fruit] folded over the bucket rim and secured with a zip tie. Large size pantyhose is also secured around the bucket rim and supported by the mesh bag. The oil goes through the prefilters and fills the upper 10gal barrel, then down the tube into the bottom of the upflow barrel. The oil settles in the upflow barrel and every time I add oil into the upper 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 into the inverted 5 gallon water jug/canvas bag filter assembly, and into the final filter barrel. The 30 gal poly barrels are more convenient for the 2nd stage, and I 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 hand barrel pump drawing from 3/4 down into the final settling barrel , through a whole house filter assembly with a 5µ filter cartridge. The barrel pump 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 dry.

The slow rate of new oil introduced is controlled by the valve on the clear oil output tube to about 5gal/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.

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.

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 three years, used for diesel fuel mixes in temperatures to 30 below, on a few vehicles, with about 70,ooo km total so far and no problems or anomalies whatsoever.

This is one of the simplest continuous process systems 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.

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

[John Galt]

If the upflow barrel is in direct sun there will be convection currents rising on the warm side and falling on the cool side, stirring the mix.
I observed that until I put the whole processing system in an opaque poly shelter tent that provided even heating and diffuse light that wouldn't differentially heat the upflow barrel.
The temperature can get quite warm in there in the summer, and the barrels are all evenly heated.

http://www.shelterlogic.com/sheds-and-storage/small/

[John Galt]

If cold upflow settling does not produce clear dry oil for your 'WVO' and your specific conditions then heated upflow settling may work for you.

Those like Ron Schroeder who developed heated upflow settling know that even heating and good insulation are essential.

Here's his description of the system he has used for many years.

[WD8CDH]

Hi John,

Only one change in my systems operation since the post that you quoted. I disconnected the hot water heating and now only use the electric ice melt cable. The insulation is good enough that the electric heat draws almost as little power as the circulating pump for the hot water.

My settling tank is inside of an insulation lined plywood box. The insulation is 2 layers of 1" foil faced foam so heat from the de-icing cable is reflected back to the space between the turns.

Also not mentioned is I heat my filter. The filter doesn't need tight temperature control so it is regulated with a simple mechanical thermostat. I keep the filter roughly 10 degrees warmer than the settling tank.

Heating allows a much higher thruput but doesn't remove PHO or fats. I can even de-water lard or butter. I don't pre-settle in cubies, I usually run my oil thru the system the day that I get it. Since I don't have a wood burning stove, I would have to find a disposal of the fats etc. if I was doing cold upflow settling.

By the way, 25 years ago, I had a compleate upflow settling system in a small apartment closet.
_________________
Ron Schroeder
WD8CDH
'85 MB 300DT 2 Tank
Since '81 former WVO conversions:
'83 240D
'80 Audi 4000D
'83 Isuzu Pup
'86 Golf
'76 Honda Civic with Kubota engine
Prior to the cars, several generators
Kubota Tractor

[David]

[WD8CDH]

Hi David,

It was more than 25 years ago, but it wasn't veggie oil. Back then it was LARD, animal fat.

My first waste oil vehicle was a 1980 Audi 4000S which I bought new and converted in the winter of 1980/81. For a few years prior to that I was experimenting with waste oil on generators.

Since I was living in a small apartment, I switched from batch settling to upflow settling at the same time.
_________________
Ron Schroeder
WD8CDH
'85 MB 300DT 2 Tank
Since '81 former WVO conversions:
'83 240D
'80 Audi 4000D
'83 Isuzu Pup
'86 Golf
'76 Honda Civic with Kubota engine
Prior to the cars, several generators
Kubota Tractor

[omar]

[John Galt]

I've made a couple of improvements recently.
The cold upflow processor produces clear dry VO. The upflow is run at temperatures below 10°C 50°F to separate the PHO, fats and the water associated with them. The clear dry oil is mixed with kerosene\D1+jetB then filtered, settled and filtered into the vehicle tank. The VO from the upflow settling can be HPT moisture tested to check for dryness. The solvents make filtering and mixing the fuel blend much easier in the cold temperatures. The only disadvantage is that HPTs aren't valid with the solvents in the mix.

I was concerned that the barrels of VO fuel mix might absorb moisture from the air, so I experimented with some Quik n' Dri.
http://biodiesel.coorga.com/quik.html

It seemed like a good idea to use Q&D in the processing as a trace moisture absorber and an indirect indicator of the moisture content in the fuel. I'm using an inverted 5gal water cooler bottle with a hole cut in the bottom to support a reusable 'canvas' shopping bag for a filter\funnel into the last settling barrel. The water cooler jug neck fits into the bung on the 30 gal poly barrel.

A Universal Water Filter cartridge fits snugly into the neck of the jug.
The cartridge is easily disassembled, and the bag containing the water treatment particles removed to provide space for about 75ml of Q&D with headroom for expansion with the cap replaced.



This Q&D column is good assurance of dry fuel and as an indicator of moisture trapped.

[gary]

Ron , what part of NY are you from...Im in the Catskills and would love to run my kubota on wvo...If you are cold upflow settling and then cf'ing does it cut the time cf'ing in half?

[WD8CDH]

It wouldn't reduce the time you need for spinning but it sure will reduce the time you spend cleaning out the CF.
_________________
Ron Schroeder
WD8CDH
'85 MB 300DT 2 Tank
Since '81 former WVO conversions:
'83 240D
'80 Audi 4000D
'83 Isuzu Pup
'86 Golf
'76 Honda Civic with Kubota engine
Prior to the cars, several generators
Kubota Tractor

[John Galt]

A commonly held misbelief is that somehow used cooking oil conforms to some international standard and that what works to clean the UVO in one case will work for everyone else.

Logic dictates this is totally fallacious. The difficulty in removing water and other contaminants depends on the type of oil used and what's been cooked in it and how long the oil has been used. Just because a process works for someone else does not mean it will or will not necessarily work for you. It has very little to do with where they live other than the ambient processing temperature available and how that effects the different components and how their contaminant load separates from the clear clean oil you want as motor fuel. It's a common misconception among new users that if they can somehow find the perfect recipe and follow it precisely that somehow they will get the same results. What they fail to understand is that it's almost impossible to have the same UVO in almost every case.

You have to experiment with different processes with your UVO to find what works best in your case. Parroting someone elses process without first understanding the basic principles will always result in frustration and disappointment, often followed by accusations toward the person whose process you tried to copy.
It's all part of the learning process. Some achieve that understanding through research and experimentation, while some others never will.

[coachgeo]

could you give us a link or something to us to read about what quick dry is?
_________________
Life; It's all in the Balance

[John Galt]

http://biodiesel.coorga.com/quik.html
http://biodiesel.infopop.cc/eve/forums/a/tpc/f/8361026472/m/2671062072?r=5021006872#5021006872

[david p]

i'm sure there is a simple answer to this, but i couldn't quite figure out one thing from your description and diagram of the upflow setting system. the oil comes in to the 55 gallon barrel via the 2" bung, and then goes out via the 3/4" bung. how do you ensure that oil doesn't seep out around the edges of the 2" bung?

Here's the relevant part of your post:

[John Galt]

The end of the exhaust tube is flared slightly [similar to this illustration of a flared pipe end]


with a ball peen hammer against a wood block so the exhaust tube seals adequately to the end of the 2" pipe coupler