I get it. Wow, awesome pump! I'm using a high quality Clear Water Pump on my 175 liter processor. When I pull my samples at the end of the mix (usually 2 hours on), I start with a fairly clean jar, run some out of the valve first, then run about a pint for the sample. Mine quickly settled into a thin layer of glycerin, too, and probably close to your 20%. I didn't assume it was representative of the batch, which is why I used the 25/75% numbers. Now I wish I'd measured the actual yield of the test batch directly to calibrate the process a little better.

I'll try another batch this weekend and report on Monday.

Cheers,
JohnO

Well I was looking forward to trying out your method this weekend Johno but something went wrong and I had to reprocess so I just drained the glycerin and carried on without doing a push/pull.
I hope to run another batch next weekend and try this out...
Jon

I was thinking about GL's vacuum pump design this weekend and I have come to the conclusion that if not built with proper heater highlimit controls that it will be quite dangerous. Even more dangerous than using a conventional vacuum pump in my opinion!
Ask yourself what would happen if the t-stat for the oil bath in the vac pump failed closed during a demething operation? Also if a water heater element is used it could ignite the pure methanol fumes when it fails, if it fails violently and produces a large arc as they sometimes do. The arc would have to be large enough to blow the oil out of the way exposing the vapors but that does not seem that far fetched in a small container of oil...

So I am just saying be VERY careful with this design and I would recommend some redundancy in the safety circuit for the heater, perhaps a level sensor along with the high limit etc...

Jon

Hello All (and johno)

I just ran a new batch but stopped short of methanol removal or acid addition. I have some questions.

Starting Stats
1. 130 liters of oil
1a. Passed the frying pan test
2. Titrated at 2.5
3. 26 Liters of Methanol
4. Added 1463g of KOH (I felt my first batch was very under reacted...more about that later) so I added 8.5 + 2.5 + .25 for good measure.

Situation #1:
1. After processing this new batch I ran a 27/3 test. (its is my first so I am little unclear about the results) I used a 600 ml sample taken from just above my circulating pump, with the temp around 130F - it was much cooler by the time I ran the test. I let the Glyc and Bio seperate for about 15 minutes. Ran the 27/3 test on Bio and let it sit for another 15 minutes. What I got was one continuous cloudy layer (which made me think it passed) but at the very bottom, I saw some oil drops - like 15 smallish oil bubbles. So I think it didn't.

Question #1: Should I reprocess? Should I test again this morning first after more separation has occurred on that sample? In the future, is there something I a missing about the 27/3 test like "don't do it when the oil is that hot" or "let it take more time to separate."


Question #2: If I failed the 27/3, why am I underacting so? I added an extra 1.75 grams/liter of KOH. The Mehtoxide was mixed in real, real slow, 60 minutes. I had just made a new titration solution of 1 gram of KOH to 1 liter of distilled water, so I think that is spot on. My Temp mixture was about 140F and I mixed for 90 minutes using a Grundfos pump which I think is moving the mixture at about 20 Gallons a minute so I am turning over the entire batch every three minutes. I could be off on this as I am not 100% certain I am calculating head properly.

Situation 2: ACID TESTING. I made a titration solution of Sulphuric Acid: One ml of acid added to one liter of distilled water. I then put in a little beaker, about 25 ml of IPA, 5 drops of Pheno, and 2 drops of KOH Titration which turned the solution a clear pretty purple. I then added 1ml of Glycerin from my 600ml sample.

QUESTION: Johno, you state that this solution with the glycerin should turn bright Purple as it is Akaline, but mine doesn't. It turns a kind of 'glowing brown', more transparent than the glycerin, so it is kind of clear, but I don't think you would mistake it for purple. However as I add the .1% acid solution, the mixture wants to go cloudy white and after about 2ml, the solution clearly turns foggy yellowish/white - so I assume this is neutral.

Question 3: Is it a problem I am not seeing purple when I add the glyc? I think it is Ok, but just wanted to be really clear.


Thanks
Doug

This is getting really interesting. On the one hand your information indicates the batch is under-reacted (dropout from 3/27 results, and glycerin titration NOT turning indicator pink are th eindicators I refer to). On the other hand your reactants sound like they "should" have worked. Fresh titration solution is always a good way to go, if there's any question, but it doesn't address the possible low activity of the KOH. If the KOH is "weak", then the base amount will be inadequate, starving the reaction.

I would first try re-reacting a pop-bottle sample, to see if you get more dropout and/or pass 3/27. If that works, then you should consider increasing the KOH base amount for future batches.

When I added my glycerin sample to the pink IPA/Phenolpthalein solution, it instantly turned bright electric purple, indicating quite high pH, much higher than just 8.3 (I didn't think to measure the pH). When I made my most recent batch, the glycerin again turned the titration solution bright purple. That was the 3rd time I've tried it, and (for me) the effect seems to be pretty consistant. Your results make me suspect that I'm over-reacting a little, since my glycerin seems to end up quite alkaline, at least compared to yours.

This last weekend I made another 175 liter batch (I haven't otherwise reported on it until now), did the acid titration only on the glycerin (ignoring the esters) and it appears to have neutralized nicely with just 120 cc weak HCL (pool chemical). The oil titrated only 2.25 KOH to start with, and I used a base of 8.5, so added 10.75 gm KOH/liter oil, and my usual 20% methanol. It mixed for 2 hours in my sealed processor at 150 F, and passed 3/27 (at about 65 F).

A thought occurs to me that there might be a 3/27 false-positive from oil that has high melting point fats that turn into high melting point esters. If they have melting point above the 3/27 temperature, will they dropout even though they're pure esters?

Hi Johno,

Still plugging away here. I reprocessed by adding 6 liters more of methanol and 150 grams of KOH. Guess what? Failed again. Added another 6 liters of methanol and and another 150 grams of KOH. Guess What? Passed with flying colors. So I surmise I got either too much water in the oil to start with, too much water in the methanol, or my KOH is 'weak.' The latter could very well be the case as the KOH is quite old (like eight months) even though it has been stored in zip lock bags and in a very dry place.

After passing the 27/3 test, I prepped the acid titration with the glycerin and low and behold, the mixture was much more purple this time - another sign I had weak KOH (or too little because of water in the oil or methanol.) Amazingly, my titration of the glycerin turned out to be .08ml. Yes that's right, it took only 6 drops to turn the solution cloudy yellow. I was surprised, so I did it again and got the same result. To even figure out how to measure the drops in ml, I counted out the drops and got 75 per ml for this syringe. So the math worked out to .08x.25*164 = 3.28ml liters. (Please double check me)

QUESTION FOR JOHN: I am assuming here the liter count is not of the original oil (130L), but now of the biodiesel & glycerin (which is basically the oil plus all the methanol added 130 & 26 + 6+ 6= 164) right? As opposed to the original 130 liters of oil I started with?

So I added the Sulphuric acid and am now de-methaning as I write this. I will let you know what happens next.

Oh for yesterday why my mixture wasn't cloudy at first, but turned cloudy after adding 2ml, for now, lets just chalk it up to newbie mistake somewhere else along the line and we will see if its relevant after my results today.

Doug

Doug: you've provided some really interesting info there, proving yet again that we learn more from our failures than our successes. You may have discovered a means to determine if a batch is fully reacted - just add some freshly drained glycerin to a blanked KOH titration solution - if it doesn't turn bright purple, then it's under-reacted. Your test result of only 0.08 indicates that you were just over the edge, meaning you used just enough KOH, but not too much. That's useful info for anyone trying to maximize a process.

Having to add an extra 20% KOH than initially calculated is a bit disconcerting. Are you using recovered/recycled methanol? Otherwise it shouldn't have any water in it, but if it's been previously used, then is probably does have "some" water. How much would it need to consume an extra 20% of the KOH? I think it would need a lot, but I'm not sure how to calculate it.

So far I've just used the beginning amount of oil for all calculations, but that's just because I wasn't sure what was needed, and it was at least a consistant starting point. I know from experience that my glycerin yield has been about 25% of the starting volume of oil, so I just assume 0.25 x Oil volume = glycerine, for calculating the amount of acid to add to neutralize it. There may be some way to use the KOH titration value to tweak the numbers, but that's a little more complicated, and I just don't know enough about the repeatability of this concept to justify more complexity.

I won't have time to try another batch for a week or two.

Cheers,
JohnO

Finally I got some time in my shed and got a batch done!

As per Johno's instructions and ratio of 25% glycerin;
I got a titration of 6.7ml for the glycerin and 0.2ml on the ester which added up to 182.5ml of muriatic acid to neutralize the 100l batch.
The batch was mostly if not all canola oil that titrated at 3 NaoH after a glycerin pretreat.
I dosed the acid ahead of the mixing pump while drawing from the bottom over about a 20min period.

It was a success! The ester passed the 3/27 instantly with flying colours just like before the recovery stage. I also did another titration on the glycerin afterwords and it instantly changed the solution indicating it was either neutral or slightly acidic.
I should add I used turmeric for the titration and RO water for the reagent.

I am off today and am hoping to get another batch done so I may have more results to post later...
Jon

JonH: that's a great addition to the data base, especially since you're using NaOH and Muriatic acid. Doug uses KOH and Sulphuric acid. I use KOH and Muriatic acid. This is starting to populate a nice little DOE (Design Of Experiment). I'll keep collecting data to see if a reliable empirical formula can be derived, ore even just a rough correlation. This looks promising.
Cheers,
JohnO

JohnO,

After letting your Biodiesel settle, are you able to get the same results as Graham by using the water shake up test? With the clear Bio-diesel and Water separation? No cloudy bio? No emulsion in the middle? And no cloudy water? The reason I ask is that it appears that after 6 days, I can not achieve this. When I skim off a sample of bio off the top of my settling tank, and mix with water, I typically get soapy water, then a thin emulsion, then cloudy biodeisel that eventually clears up (4 more days). But clearly, I do not have 'Clean Bio.'

After processing, my bio passed the 27/3, so I assume that means I reacted properly. So I suspect perhaps that the KOH soap does not drop out like the NaOH soap. I am not at all certain of this because after re-reading the methanol recovery threads more closely, I am certain that the methanol I used on this batch, which was recovered methanol, was nowhere near the purity you get at the pump. I am setting up a hydrometer in the next day or so to get some idea how bad it was. This also would explain why I had to add so much extra 'methanol' to pass the 27/3.

Now as I need to buy more Catalyst for my next batch, I was really interested to find out if the KOH is working for you or should I switch to NaOH, like Graham.

Thanks
Doug

Doug: Just to be clear to anyone reading this, I’m not processing through the entire Push-Pull process. For now I’m just trying to figure a way to use sampling to determine the amount of acid to add, thereby avoiding that part of Graham’s method in which he adds phenolphthalein to the whole batch and watches for a color change. After I add the acid I then drain the glycerin and “air wash” the biodiesel (evaporate off the methanol with a spray dryer and let it settle). It gets to settle for a week or two (6 days has been enough in warm weather) before it gets pumped through a Luber-Finer filter into the storage tank. I’d guess the liquid temperature while it’s settling outside in open air is around 18-20C.
It’s passed the water-shake test easily, with clear water and non-cloudy biodiesel, no cuff/emulsion in the middle, although I haven't water-shake-tested the more recent batches. A sample from one of my first test batches has been sitting in my south window for a couple months. It has golden clear BD sitting on top of crystal clear water, but has developed a razor-thin opaque film separating the two liquids. It’s not an emulsion, but may be a stearate or other cousin to soap residue, or maybe just high-melting point esters (we found some of those in completely reacted biodiesel we had analyzed with GC-MS. They had a melting point of 70C!).
I think I need to repeat the water-shake test on the most recent batch. I’ll let you know what it does.
Cheers,
JohnO

Ok thanks Johno. But at least we now know that using KOH, the acid, and settling does create bio that passes the Graham water shake up test. I feel the water shakeup test is the closet home test for ATSM quality for now. I hope to have some folks over at cal tech actually run a CG test when I can pass this test.

Which leads me to think one of four other things is happening.

1. The water contaminated methanol is causing my problem.
2. I am getting a back reaction as I am using heated bio diesel to extract the methanol from the Glycerin and Bio. This probably means I need to be much more careful with my temps during recovery. I wonder if KOH or NaOH is more susceptible to back reaction or am I just over thinking?
3. I am not waiting long enough (6 days) for the stuff to settle out of the Bio.
4. Something I have not yet thought of yet.

Right now, I have 60 gallons or so of Bio that I need to clean and consume before I get another chance at making some more. So it might be a month or so before I run another batch. I think next time I will:

1. Use NaOH
2. Limit my temps to 165F during recovery and run recovery much longer... like 8 hours.
3. Run a 27/3 test after my reaction AND run another after methanol recovery to see if there was any back reaction.


ONE QUESTION:
If I did have a back reaction, what really happens? What would I test for and what test would I use. Does it change the PH of the Bio or does it basically mean that I would see more soap and emulsion?

Doug,
In my experience using the settling method for washing, it takes at minimum 2.5 to 3 weeks of settling before I can get a shake test to bear clear water and no emulsion. I use NaoH to process too. I dont think you are doing anything wrong in your process that would effect the settle time. Settling time in my opinion is directly proportional to the amount of methanol left in the bio and how warm it is while settling.
I believe that a combination of electrostatic seperation and wood chips is going to be the best solution for dropping the time it takes to settle...

quote:

3. Run a 27/3 test after my reaction AND run another after methanol recovery to see if there was any back reaction.

Yes do that for sure, it will tell you if a significant back reaction has occurred.

quote:

ONE QUESTION:
If I did have a back reaction, what really happens? What would I test for and what test would I use. Does it change the PH of the Bio or does it basically mean that I would see more soap and emulsion?

To the best of my knowledge, other than GC testing the 3/27 or PHlip tests are the only ones that can give any indication of a back reaction. A back reaction is just that, the ester converts back into TG's, DG's and MG's
Jon

Sitting around waiting for peeps so I'll give this a go.

Tentatively, I've decided push-pull & neutralization isn't worth it. After acid titrating & pH testing homogeneous & settled samples with various solutions of alcohol & dist water, and getting virtually identical results, it only seems to further verify what you guys have already quantified - that almost all the leftover caustic and most of the methanol remains in the byproduct layer. I pretreat, so it makes no sense to take more time/energy to neutralize & remove chemicals which have an obvious benefit in the next batch.

I still think neutralization might be worth it (and more touchy) for the ester portion, retaining the benefits of higher recovered meth purity, better soap & residual glyc dropout which should increase filtering efficacy.

That said, please keep in mind I'm not slamming the process, only pointing out that using it seems to be more based on personal preferences. Better for an all in one tank, at one time process with methanol recovery & an abundance of time for settling. Not so much for throughput.

Also, I have no empirical evidence for differences between pretreat w/w/o caustic neutralization or meth recovery. Just seems to make sense.

Jdoughy,

You make a good point. If you have high titrating oil, then pre-treat is the way to go and neutralizing the caustic makes little sense.

I find, the issue of this message board and a little with your post is that few people (including myself) have done little quantitative testing. It mostly all conjecture and simple observational results and compounding it all, is that many of those conjectures are based upon older conjectures. I hope to make some kind of impact on that in the next few weeks. Here is what I think needs to be tested to see what makes an efficient process.

WVO STAGE:
1) Testing for water in WVO. The hot pan test is excellent to get an idea if there is water or not in the oil but hardly useful to see how much water removal makes the difference. It needs to be more readily standardized. If there were at least a set of videos made of bubble quantities compared to PPM so that people can at least have some visual reference to water PPM, that would be a start.

2) Base Titrating Oil (using Caustic solution.) Pretty well established test.



JUST AFTER PROCESSING
1) Fuel must pass a 27/3 test at 68F. Great test for finding if you have under-reaction of triglycerides. BIG MISTAKE to think this test tests for mono/di (hey I thought it did).

2) Acid titrate glycerin and Bio separately at 68F. (no reason except that if it is good enough for the 27/3, I make the assumption that enough separation has occurred to be good enough for this test.) Indicates where the extra caustic really is. From current testing, it appears almost all is in the glycerin. TEST COMPARISON: Batches that have been PRE-TREATED vs non-PRETREATED.

3) How much mono and di-glycerides are created using this method. Results not really important at this stage, but it would REALLY MAKE A DIFFERENCE to have it as a reference for later tests. TEST PRE-TREATED vs non-PRETREATED.

4) Methanol Percentage Test. Results not useful here but will be used for comparison later.

5) Water test in PPM. Results not useful here but will be used for comparison later.



METHANOL RECOVERY - FULL PUSH/PULL METHOD:
In the Push/Pull method: Add acid and Vacuum/Heat (recover methanol) from Glycerin and Bio. Drain Glycerin.

1) How long to do this?
2) At what temps?
3) How is Methanol purity effected?
4) Rate of recovery?
5) How much mono and di-glycerites are created in back reaction using this method. Compare to the number aquired in the last test.
6) Soap Test PPM just after reaction when Bio cools down to 68F. Will tell you how much soap was created.
7) Methanol Percentage Test. Will tell you how much methanol did you remove.
8) Water test in PPM. Will tell you how much water is left in the Bio.

Now what is the difference between this way and by removing the Glycerin first, then by running the process of removing the methanol out of just the bio itself. Might this lower the back reaction and therefore less mono/di-glycerides?


METHANOL RECOVERY - METHANOL RECOVERY - BIO ONLY:
In the Push/Pull method: Drain Glycerin, Add a drop of acid, and recover methanol from Bio.

1) How long to do this?
2) At what temps?
3) How is Methanol purity effected?
4) Rate of recovery?
5) How much mono and di-glycerides are created in back reaction using this method. Compare to the number acquired in the last test.
6) Soap Test PPM just after reaction when Bio cools down to 68F.
7) Methanol Percentage Test. Will tell you how much methanol did you remove.
8) Water test in PPM. Will tell you how much water is left in the Bio.

This second method should also be tested with Pre-Treatment method vs. non-treated.

Polishing
I am getting some amazing shake 'em up tests by filtering through wood chips (Redwood bark really). So I would like to know.

1) Soap Test PPM. Will tell you how much Soap did you remove.
2) Methanol Percentage Test. Will tell you how much methanol did you remove.
3) Water test in PPM. Will tell you how much water is left in the Bio.
4) How much mono and di-glycerides are left over. (Not having an affordable way to test this is killing me!)


This all is a bit rambling as it is coming off the top of my head. But if anybody has any other test suggestions, post them. I am willing to do all these iterations to test but I need to find someone who has a CG machine who can run all the mono/di-glyceride tests as that is a key element missing.


Then hopefully we will have some quantitative idea what is really going on and make a better roadmap for the people who come after us.

Doug

quote:

Tentatively, I've decided push-pull & neutralization isn't worth it. After acid titrating & pH testing homogeneous & settled samples with various solutions of alcohol & dist water, and getting virtually identical results, it only seems to further verify what you guys have already quantified - that almost all the leftover caustic and most of the methanol remains in the byproduct layer. I pretreat, so it makes no sense to take more time/energy to neutralize & remove chemicals which have an obvious benefit in the next batch.

jdoughy,
I have come to the same conclusion.
My initial interest in the push/pull process was to be able to demeth the glycerin and ester in one shot so I could just drain the glycerin and dispose of it demethed and never have to process or deal with it again... Then along came the great glycerin pretreat thread...
The last 3 batches I have done I just processed like normal in order to use the glycerin to pretreat the next batch, some dirty oil I have been stock piling over the winter.
FYI; I did do a pretreat with some glycerin that had been neutralized and demethed ala the push/pull and let me tell you that that was a stupid move! Its a long story on the recovery from that disaster but lets just say thank god for my vacuum pump and torch for cleaning solid glycerin out of my pipes! Anyways the moral of the story is the pretreat still worked great even though the glycerin was neutralized and the methanol was removed so there is obviously more to it then just the left over caustic and methanol.

To sum up if I have a bunch of clean dry oil that will not benefit from a pretreat I will do the push/pull to recover the extra methanol, otherwise I will save the time and energy and just carry on pretreating...
I guess I will have to make a glycerin still one day for all the pretreat glycerin I will have that still seems to have a significant amount of methanol in it...
Jon

quote:

My initial interest in the push/pull process was to be able to demeth the glycerin and ester in one shot so I could just drain the glycerin and dispose of it demethed and never have to process or deal with it again... Then along came the great glycerin pretreat thread... Smile

Ditto. Sucks re: solid byproduct. KOH even comes out really thick after pretreat, can't imagine NaOH, at least not yet. I have another idea for base/base...

Doug, your point is valid and well received. In defense, (probably of many people, not just myself) one of the reasons I haven't done any hard testing on the pretreat is that although it's interesting to quantify "how much better/worse" one procedure is compared to another, it's not as important (to me) as getting things accomplished. Time is money, and I have precious little of both. A lot of valid testing is performed on an informal basis with variables that aren't, and don't necessarily need to be, controlled. I don't believe the lack of posted records invalidates results. On the other end, b/c those variables often CAN'T be controlled in the real world, I generally take issue with "definitive" results conjured up in a lab. Most of us brew at home with a wide array of setups, environmental conditions, and feedstock. In short, testing has it's limitations. I'll initially take the logical opinion of someone who's made 100 batches in his/her back yard over the numbers from a lab rat with a bunch of erlenmeyer flasks and a hot plate.

However, I completely agree re: all the conjecture. I wholeheartedly encourage you to test away with your setup & report the results. From what I've seen thus far, yours will be a welcome addition to the knowledge base. I think your list is great, and suggest you start another thread where we can all contribute and help refine things further.

I took a ridiculous amount of time to precisely test & record the results of neutralization. The sad part is, the tables were annihilated before I had the chance to input everything into the computer. All I can say is that the results were pretty telling in a mass of redundant samples from only 4 batches and I'll stand behind my prior claim, and not just for high titrating oil. IMO there's a gray area of benefit between acid/base & pretreat/base, and another smaller one between low ffa & middling feedstock. If the acid/base team over there can iron things out, I think there's a good chance home brewers will wind up with a broad range of options for high yield.

So, anecdotally, for me there was a significant difference between the success of pretreat w/w/o neutralization & demething. Pretreat still works if the byproduct is down around 8.2 and most of the methanol has been recovered, just not as well. Most of it follows logic. But will it still work if byproduct is totally neutralized, down around 7? Does anyone know what reaction occurs between glycerin & ffa, if any? I don't believe the pretreat questions can be answered fully until ffa stripping via residual caustic is eliminated.

This was also posted as its own topic, but I wanted to add it here as well so it doesn't get lost. The most important part is the last part.

Ok, so I got to thinking which is always a dangerous thing.

For the Bromophenol Blue Soap test, we make a Molar solution of acid with which to titrate our finished biodiesel.

For those unsure of what a Molar solution is, its basically a series of calculations that use weight to figure out how many actual molecules are in a solution. So when you see .01 M (molar) or .01N (normal) all the math is already done for you, no need to worry about purity. From that Molar solution number, you know how many molecules are in there.


However, we are not using Molar solutions for the KOH/NaOH titrations. Why?

Wait, am I answering my own question here? Perhaps we are when we are calculating 7g for KOH and 5.5g for NaOH and then dividing by the purity percentage? I suspect so but perhaps someone with a little more chemistry skill (or a degree) can confirm this.

So lets assume that I am correct above. We got a 1% solution of KOH/NaOH solution, then do all the Molar math to use the correct amount of catalyst. Johno suggested awhile back to use 1% HCL concentration to calculate how much acid to use. Go to Johno Middle of the page I don't think you can use 1% HCL/H2SO4 as way to titrate and then do the multiplication (.25 glyc * Batch size) to simply calculate acid ML. You either need to make these Molar solutions or have the math in place to to figure out the correct amount of acid to use.

Anyone with some learned experience in chemistry comment.

Doug

I ran another one tonight, same math and setup as above except this one was all canola that was not glyc pretreated and titrated at 1 NaoH.
Acid dose titration results;
Glycerin titrated at 2.4
Bio at .75
Which adds up to 150Ml of acid for the 100L batch.
I also titrated the bio before and after the neutralization and recovery.
Before, neutral barley a change in depth of red and one drop made it dark red again.
After, Titrated at .3 NaoH
So something is making it slightly acidic but what? FFA's or left over acid?
See another discussion about the acid over in the fuel quality section here.
Jon

Sorry to jump into this conversation all of a sudden.

I've got a few BASIC questions relating to the added benefits of the GL-Eco design and the Push-Pull design.

CONTEXT: Like many others, I've been successfully distilling and reusing methanol from biodiesel for a while now. I've recently questioned the worthiness of the added complexity of the push-pull design as compared to the original GL-Eco design. I know that in the case of the Push-Pull, the goal was methanol purity. I get that. BUT it seems to me that with proper PID boiler heat control, methanol purity with the GL-Eco design can be improved.

QUESTIONS:
A) Is it possible to recover methanol from glycerin and biodiesel together using the earlier GL-Eco design with a venturi and plumber's delight condenser?
B) With properly dialed-in heat control, is that methanol going to be pure enough to use in the next batch?
C) In this scenario, is it necessary to neutralize the biodiesel and glycerin solution with acid? More specifically, is a very slight back reaction going to dramatically affect finished fuel quality?
D) Is anyone using the earlier design with NaOH lye and recovering methanol from the whole batch (glycerin and biodiesel) without problems of glycerin turning to stone or other noteworthy problems?

The developments, experiments, and experiences that I have read here testify to the sense of purpose that we all seem to share. As one of my friends once told me, "There are many roads to paradise." I'm just trying to find one and stick to it.

My next goals for my biodiesel production are to figure out a simple and sufficiently effective method recovering methanol from the whole batch, then air circulate and remove soap with a centrifuge. I'll be experimenting with a centrifuge setup over the next month and see if I can be done with the water washing forever!

Thanks for reading this post.