Plantoil/diesel conversion basics
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danalinscott

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What would actually be the best to use for dewatering? havent searched so much around this site but have read and spent some time in your other forums. It seems to me danalinscott is the best person to conclude based on so many experiences of others with different perspectives.


In my experience there are three reliable methods to dewater wvo.
Which is most practical depends on the volume of wvo that needs to be dewatered on a daily basis and how contaminated the feedstock WVO is.

 1.For relatively uncontaminated wvo simply prefiltering to 10 microns or better and settling under gentle heat is the most practical. Care must be taken to not create strong convection currents in order to do this however this is not terribly difficult and the material and labor costs are low. A relatively large amount of settling tank capacity may be needed if large volumes of throughput are required.

2. Mist washing and then prefiltering  and settling under gentle heat as above. This is most practical if the wvo feedstock is very contaminated since filters will tend to require constant replacement/cleaning otherwise. Adding a mist washing stage to prefiltering/dewatering is a simple low cost way to decrease labor and materials costs for small commercial prefiltering operations.

3. Continuous centrifuges allow nearly instant prefiltering AND dewatering. This dramatically decreases labor costs as well as the amount of costs involved with large capacity settling tanks. But continuous centrifuges are very expensive.

To test for water in VO Use the Hot Pan Test (not to be confused with the "Crackle test".

The hot pan test.

Smear a finger of wvo across a fry pan (cast iron preferred)as a temp check.

Keep the sample of wvo to be tested handy. Enough for 1/4"-3/8" thickness covering the bottom works best.
Heat the pan on high temp until the smear begins to produce smoke then pour in the sample.

NOTE:
Do not pour in a sample with any visible water. If water droplets are visible no testing is needed. There is water present in your sample. Visible droplets of water will spatter hot oil out of the pan and may cause burns or fire.


Look closely at the bottom of the pan where the oil meets it. Are there very small bubbles forming. This indicates some suspended water. The number of bubbles indicates how much water is present in suspended form.

I usually accept a FEW suspended bubbles (up to 3 per sq inch maximum). Lots of small bubbles is unacceptable to me. If crackling or popping is heard..way too much water is present for the VO to be safely used as fuel.

I have tried to keep this test as simple, cheap, and translatable as possible. It works....though it is not "foolproof". 
 

NOTES:
Do not pour in a sample with any visible water.

If water droplets are visible no testing is needed. There is water present in your sample.

Visible droplets of water will spatter hot oil out of the pan and may cause burns or fire.

Do not average bubble count. The visibility of bubbles is dependent on the temp of the underlying pan and this may be regionalized depending on your heat source.

If the pan has been washed or not used previously it must be "seasoned" to make certain that no moisture is trapped in the pores on the surface of cast iron.

False positive results (bubbles) can be obtained if the pan is WAY too hot..or if solvents are mixed in the WVO.

False negative results (no bubbles) are possible if the suspended water has high concentrations of salt/sugar/ acids.



 


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danalinscott

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Reply with quote  #2 
Why does wvo need to be dewatered?
Two types of water exist in VO:
1. Free water

and

2. Suspended water

Free water exists in diesel fuel and is one reason that a water drain or very large filter is provided on most diesel engines. Even a teaspoon of water passing through the Injector Pump (IP) or Injectors can severely damage them requiring replacement. Since these are very expensive components great care is taken to prevent free water from passing though them.

Suspended water does not exist in diesel fuel since it does not have sufficient viscosity to keep even microscopic droplets of water suspended for long. WVO and SVO DOES  have sufficient viscosity to keep microscopic droplets of water suspended for very long periods and so provisions must be made to remove not only the visible (large droplets of) free water but invisible (to the naked eye) suspended (micro droplets of)  suspended water as well.

Suspended water causes damage to IPs and injectors via a process called cavitation.  Cavitation is discussed later in this discussion in more depth.

In fact there are many problems that can be traced back to having a root cause of water in the VO/WVO fuel.

 When I am presented with a troubleshooting issue in a conversion which does not seem to involve air leaks I immediately ask how the VO/WVO fuel is being prefiltered and dewatered. Nearly 50% of the time adequate dewatering turns out to be the basis of the problem. This is probably why I am perceived as being simply obsessed with dewatering of VO fuel.  And possibly why when I mention dewatering as the basis for a problem many dismiss it as due to my (alleged) obsession with water in VO/WVO and dismiss that as a real possible path to the answer to a problem.
After all....how could small amounts of water in WVO/VO fuel be the root cause of SO many seemingly different and unrelated VO conversion problems?

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cfakcs

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Ok Dana, I have your plans and have read them over . I am planning on getting materials together as soon as possible.IYO is using your system all I need to dofor filtering and dewatering? I am using primarily Pnut oil that was used to fry Chicken and also Pnut oil used for fries that were prefried in partially hydogenated Soy oil.There is very little settlement of any kind after sitting in cubes for days or even months.

 

Thanks

 

Burns

jolan

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Reply with quote  #4 

If I use a centrifuge, i do not need to filter it anymore? a centrifuge spins the liquid at high speed to separate varying densities. It has dozens of thin stainless steel bowl-shaped plates which have to be cleaned after every use. Is this the type you are mentioning? Thanks.

 

Quote:
Originally Posted by danalinscott

Why does wvo need to be dewatered?

Two types of water exist in VO:

1. Free water

 

and

 

2. Suspended water

 

Free water exists in diesel fuel and is one reason that a water drain or very large filter is provided on most diesel engines. Even a teaspoon of water passing through the Injector Pump (IP) or Injectors can severely damage them requiring replacement. Since these are very expensive components great care is taken to prevent free water from passing though them.

 

Suspended water does not exist in diesel fuel since it does not have sufficient viscosity to keep even microscopic droplets of water suspended for long. WVO and SVO DOES  have sufficient viscosity to keep microscopic droplets of water suspended for very long periods and so provisions must be made to remove not only the visible (large droplets of) free water but invisible (to the naked eye) suspended (micro droplets of)  suspended water as well.

 

Suspended water causes damage to IPs and injectors via a process called cavitation.  Cavitation is discussed later in this discussion in more depth.

 

 

danalinscott

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Reply with quote  #5 
Quote:
Originally Posted by cfakcs

Ok Dana, I have your plans and have read them over . I am planning on getting materials together as soon as possible.IYO is using your system all I need to do for filtering and dewatering? I am using primarily Pnut oil that was used to fry Chicken and also Pnut oil used for fries that were prefried in partially hydogenated Soy oil.There is very little settlement of any kind after sitting in cubes for days or even months.

 

Thanks

Burns

The Simple Hand pump Pre-filter will remove suspended water and particulates sufficiently if used as directed. Always test your processed wvo for water content while learning the de-watering regiment though. Since this is "hot filtering" all fats and hydrogenated oils will pass. These are perfectly OK to use as fuel however some conversions must be upgraded in order to use them with out problems. Usually these upgrades are mainly adding more heat to the filter so the high Melt Point fats/hydrogenated oils do not coat the filter element and "clog" it but in some of the more primitive conversions additional heat must also be added to the tank, preferably in the form of a heated fuel pickup.


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danalinscott

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Reply with quote  #6 
Quote:
Originally Posted by jolan

If I use a centrifuge, i do not need to filter it anymore? a centrifuge spins the liquid at high speed to separate varying densities. It has dozens of thin stainless steel bowl-shaped plates which have to be cleaned after every use. Is this the type you are mentioning? Thanks. 

 

The centrifuges used commercially for de-watering wvo fuel are large "continuous duty" centrifuges which allow the watery emulsion that is extracted to be continuously removed. This emulsion also carries the  concentrated particulate matter out of the unit. Currently there are no continuous centrifuges available that are inexpensive enough for use by non commercial wvo fuel users.

 

Quote:
Originally Posted by jolan

Thanks. Another question now regarding centrifuges. Would any typical centrifuge machine work? As far as I know a centrifuge spins the liquid at tremendously high speeds to separate substances with different densities.I've seen it used in edible oil manufacturing and pharmaceuticals.

 

Theoretically any centrifuge could work. But the practicalities are that if the unit must be disassembled to remove accumulated water and particulate contamination it may require a lot of maintenance. Those units that have a feature which allows the separated water/particulate "sludge" to be removed without disassembly are much more practical for this use.


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lucybleu_22

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Reply with quote  #7 

Dana,

 

I am not quite clear on a couple of points.  First, You mention using a hand pump prefilter, for removing water.

 

"The Simple Hand pump Pre-filter will remove suspended water and particulates sufficiently if used as directed"

 

Does this remove enough water for use, or does it still require dewatering?

If not is it possible to "filter" the water out? Or is the best method to just heat the oil, let it cool, and separate?

 

Thanks again

 

Che'

danalinscott

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Quote:
Originally Posted by lucybleu_22

Dana,

 

I am not quite clear on a couple of points.  First, You mention using a hand pump prefilter, for removing water.

 

"The Simple Hand pump Pre-filter will remove suspended water and particulates sufficiently if used as directed"

 

Does this remove enough water for use, or does it still require dewatering?

If not is it possible to "filter" the water out? Or is the best method to just heat the oil, let it cool, and separate?

 

Thanks again

 

Che'

 

The simple handpump prefilter unit is designed to dewater wvo sufficiently for  use as fuel. It was intended as a simple and inexpensive yet effective way to process WVO into fuel for those needing less than 140 gallons per week. It is much simpler and quicker to settle out suspended water once particulates larger than 10 microns have been removed. 


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dlorimer

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Reply with quote  #9 
Ok ....  What about simply boiling the water out?  I heard of one guy doing this, and he seemed to be doing fine.  You simply raise the oil to the boiling point of water (which is lower than the boiling point of the oil, of course, and keep it mixing for awhile.  What's your reaction?
danalinscott

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Quote:
Originally Posted by dlorimer
Ok ....  What about simply boiling the water out?  I heard of one guy doing this, and he seemed to be doing fine.  You simply raise the oil to the boiling point of water (which is lower than the boiling point of the oil, of course, and keep it mixing for awhile.  What's your reaction?


The problem is this just does not work to remove enough water to produce safe fuel without the addition of high vacuum and mist washing. Suspended water will remain. It will give a false positive in the Hot Pan Test because the "water" in wvo is not pure water. Far from it. It is water AND every water soluble contaminant in the wvo. These include acids, salts, sugars, etc.

These water soluble contaminants just get concentrated when water is "boiled off" until the the water/contaminant micro droplets are too laden with salts/sugars/acids/ etc to allow the mixture to vaporize at the temperature of boiling water. At this point you have a wvo that when tested for water may (falsely) indicate no water is present..even though quite a bit remains. And that "water"  which remains in the wvo is even more likely to cause damage than before it became a concentrated "soup" of water soluble contaminants.

Did I mention that trying to boil off water also uses WAY more energy than any other method of dewatering wvo?

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danalinscott

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Quote:
I was under the impresion that the oil would be heated to around 150-170 to let it settle, as that would be the temp that it would be running through the filters and system at, but could you tell me what the prefiltering advantages and disadvantages are of heating it to different temps? Is 90-100 always best, or should you heat the entire barrel to 170, then let it settle out naturally?


There is no advantage to heating the VO to those temps IMO...and several disadvantages. The main one is that the more heat you add the stronger convection currents become and the longer dewatering takes. Strong upwelling currents tend to remix settling water rather than allowing it to settle below the heating element.

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samueleca

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Reply with quote  #12 

I just got a free used electric water heater. It seems like a perfect solution for the heating/dewatering phase. I just bought Dana's plans, but this seems even easier and more energy efficient, and since the heater is free....
Here is the new plan. Prefilter to 10 microns using a house holdfilter and pump into the water heater. Bring to exactly (i don't know how many) degrees. Let set for a few hours (i don't know how many) then filter through a goldenrod or stanadyne into final storage, or car.
Am I missing something.


I would appreciate feedback on the temp, time, and polishing filter.

danalinscott

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Quote:
Originally Posted by samueleca

I just got a free used electric water heater. It seems like a perfect solution for the heating/dewatering phase. I just bought Dana's plans, but this seems even easier and more energy efficient, and since the heater is free....
Here is the new plan. Prefilter to 10 microns using a house holdfilter and pump into the water heater. Bring to exactly (i don't know how many) degrees. Let set for a few hours (i don't know how many) then filter through a goldenrod or stanadyne into final storage, or car.
Am I missing something.


I would appreciate feedback on the temp, time, and polishing filter.


Dewatering does not proceed very well until after wvo is prefiltered to 10 microns or better. I suggest looking at the Frybrid Still. It does not work as well as the Simple Handpump Prefilter Unit...but unless you need over 80 gal per week it should work OK.

(PS. I notice you posted this same post in 3 places on this forum. Please don't do that. Pick the best place and post it..or..two best places at most.)  Thanks.

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samueleca

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Reply with quote  #14 
Dana,
Sorry about the multiple posts. I was thinking that I might get answers from different people who look at different threads.

I do plan on prefiltering through a 10 micron filter, before the waterheater (Which is 30 gallon). Then draining crud and refiltering. Do you think the Goldenrod 595 or the stanadyne polishing filters are preferable. I know you use the goldenrod in you plans, I dids not know if the waters eparator in the stanadyne was a good redundant safety measure (also comes in smaller than 10 microns.

Then into the car and goldenglow.
Scott 
danalinscott

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Quote:
I dids not know if the waters eparator in the stanadyne was a good redundant safety measure (also comes in smaller than 10 microns.

Then into the car and goldenglow

Quote:
Do you
think the Goldenrod 595 or the stanadyne polishing filters are preferable. 


Remember that NO water seperator will remove suspended water and most spin on tyep filters act as a water seperator as long as they are mounted correctly. Make sure you test with the HPT to make sure water levels are not excessive...especially if you are using a Frybrid Still oe other hot water heater based water settling unit.

As long as you are going to use a GG as an onboard filter prefiltering finer than that does not seem to make sense to me.

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