As in the methanol is 22% of the batch size, so at 12.5% it only needs just over half the methanol we put in for the reaction, the excess is just to help push the reaction.

Mine only really needs 30 litres but when I was adding the recovered there was about 2 litres left in the bottom so I just carried on pouring figuring the extra would compensate for any loss in purity.

And Nige, I agree with Jim if you get demeth, bubble, settle right it doesn't need any more than a quick run through an old sheet, jeans, t-shirt.

This last whole batch demeth I've just done I drew a sample and it settled out the glyc, and whatever soap there might have been, in about 5 minutes flat. It was so awesome and I went on so much about it to the family that I got Mahli asking if she could see it, so we strirred it all up and watched it settle again, I checked after leaving it overnight and the level of the glyc hasn't dropped any lower than it had after just 5 mins, but bio was now completely clear on top and the glyc is solid.

I have a sample of my last whole batch demeth bio still with the Glyc in it, I'll do a 50/50 with distilled water as Graham suggested and see if there are the dreaded mono and di's in it.

Jim

have you seen the glyc settling fast? if not stir up some of what you have and watch it, though it might need warming if it's solid like mine.

How did you fair with soap?

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[Edited on 18-7-2009 by Chug]

I pump from processor at approx 80°C and bubble overnight (as my pump is only 3.5L/min, not 70L/min like Jim and others so they can do it in much less time, usually a few hours) and it's still luke warm in the morning even in the depth of winter, but it is 135 litres to cool

I did wrap a blanket round it in the 1st week of Feb cold snap.

I have one drain at the bottom and one other tap about 4 inches from the bottom, I originally intended fit another tap about half way up, but the way the soap settles within a day you don't really need it unless you are in a hurry.

So no additional heat required?

Nige

sorry Nige

didn't really answer your question,
no additional heat just from de-meth temperature to ambient, it does work cold too it just seems to take a little longer.

Cheers Buddy.

I can see a few plant modifications coming on.

Nige

No Nige, it's not Buddy, it's Chug and I'm Jim.

Oh thanks Jim, just when I make a friend you ruin it!

I popped out to me garage and had a look at yesterdays batch an hour or so back and I'm happy to report that the shake em up test has seperated nicely and after 24 hrs no DWS at the bio/water interface as in the first two batches, so I'm leaning to the fact that stopping demething at my calculated excess over the stoichiometric quantity is what helped, it's the only thing I changed except for it being a bigger batch.

And it was getting dark so hard to see clearly but after 24 hrs my settling tank looked clear to the bottom and no sign of the usual soap ring halfway across the bottom, which confirms the samples I took before and after bubbling showing almost zero soap, and all this with no prewash too...luvvly.

So I'm liking what I find so far and will persevere with more trials, but even if you do single stage or standard 2 stage it's still gotta be worth giving a whole batch demeth a try just to see glyc and soap settling out so quick.

Chug,
My next batch will be converted using my eductor, I'm hoping to shorten the conversion time but I'll have a go at your calculation and stop demething when the predicted amount has been removed.

Sorry about losing you a new friend, I bet he'll be back, y'know bad penny and all that.

Chug, Just finished another whole batch demeth as I usually do now days, I had to add stage 1 Glyc and process of extra hour to get good 3/27 pass. I used 7% prewash to hopefully KILL the chance of a reverse reaction, worked great still 3/27 pass, and bubbling overnight now.

I'm still here Jim and I'm still friends with Chug!

BTW I was only thanking Chug for answering my question on addition heat requirements.

I was always thank those who help me. I was brought up proper you know!!

Nige

stump

I'm confused.com?

are you saying you did you did the standard 2 stage with draining 1st stge glyc?

and are you saying you did your whole batch demeth without acid?
or with acid?

I'm confused mate?

mind you it don't take much sometimes



[Edited on 24-3-2009 by Chug]

Sorry Chug,

I didn`t explain myself well at all did I, what I meant was I did a normal 2 stage method and when I added back the stage 1 Glyc I had to continue processing for an extra hour to get a 3/27 pass, were normally, when Iv`e added stage 1 Glyc back I test for the amount of acid needed then add that and demeth.

This time as I should have said earlier, I had to process longer, then test for the amount of acid needed, then add the 7% prewash, then the acid, then demeth. Worked out ok in the end went up to 78c and ended up with around 2lt of meth back.

Hope this make sense.

PS I think I posted in the wrong topic if it can be moved to the whole batch topic please do so, thanks stumpy.

[Edited on 24-3-2009 by stumpy]

Stumpy

have you tried the whole batch demeth without the prewash, or would you be willing to give it a go?

Nick,
did you do your 80 litre whole batch demeth yet?

Cuckoo,
did you do your 250 litre whole batch demeth yet?

anyone else tried demething a whole batch this way yet?

I am getting megga confused.
Are we saying that the current thinking is
Dewater oil
Titrate
Split methoxide 80/20
Process oil with 80% for an hour.
Add 1mg/l (i.ei 150g for 150L batch) to the remaining 20% methoxide
without drawing off the glycerol (from the 80% process) add the 20%+1g/l
cook fro a further hour or until 27/3 passed.
Then without a prewash demeth the whole batch.
then allow glycerol to settle ,draw it off and decant into settling tank
Bubble overnight

Frisp

It is a little confusing as I'm incorporating two new methods in one go!
Modified 2 stage process AND Whole batch demething together.
The two do not have to be done together and if you are not so experienced I suggest only trying one at a time.

And it's not so much current thinking as myself and one or two others experimenting with different methods trying to find ways to reduce the time taken, and inprove the quality of the finished bio.

You can try this whole batch demeth on any type of process whether it be single stage or standard 2 stage 80/20, or modified 2 stage.

As for the modified 2 stage: Some people find they needed to add an extra 1g per litre if the 2nd stage failed the 3/27 test.

Adding the extra 1g per litre seems to be about the average amount to get a pass if it fails the 3/27 after the 2nd stage methoxide injection.

Although this isn't the correect thread
I'll repeat the method to clarify

1. Dewater oil.
2. Titrate.
3. Split methoxide 80/20.
4. Process oil with 80% of the methoxide for an hour, or for your usual 1st stage length of time.
5. Without drawing off the glycerol (from the 80% process) add the remaining 20% methoxide.
6. Mix for a further hour, or for the usual 2nd stage length of time it normally takes you to get a 27/3 pass.
7. Do a 3/27 test, If it fails the 3/27 test add 1g NaOH per litre (i.e 150g for 150L batch) and continue mixing until 3/27 pass is obtained.
8a. Either finish as per your normal process,
OR
8b. Without doing a prewash demeth the whole batch.
Then allow glycerol and soap to settle superfast, draw it off and decant bio into a settling tank
9. Bubble overnight
10. Filter as per your preferred method and use.



[Edited on 27-3-2009 by Chug]

Thanks Chug
That makes it Uber clear thanks.
Im going to put a batch on in the next couple of days and I shall give both methods a go and let you know how it goes. Im running a Trooper which has already been converted to run on SVO so a bit of oil remaining in the batch doesn't worry me.
Im keen to try demething the entire batch as I have always been concerned about nasty fumes when drawing off hot meth laden glycerol into cubees.

Chug,

Iv`e done Demething with and without the prewash, both worked fine, but I must admit to feeling safer/happier with the prewash added.

The batch I made a couple of days ago is crystal clear, I`m going to Centrifuge it tomorrow then pass it through my Maple shavings and test for soap, in the past Iv`e just passed through the shavings, I want to see what is collected in the Rotor if anything.

BTW I use 10lt of Methanol per batch of 50lts

[Edited on 25-3-2009 by stumpy]

I calculate that you should be able to recover 3.75 litres of your original 10, how much do you normally get?

no 7. Bob

but only if it fails 3/27 after no 6.

I've edited the steps above to (hopefully) make it easier to understand.



[Edited on 27-3-2009 by Chug]

Chug, I wasn't far out with my figures.
I got 4ltr from 11 and a small fallout. I'm going to do 3/27s from 3.5ltr next time.

I've posted a word doc with a guide to batch size and approx how much methanol we should be able to reclaim from the whole batch after the 12.5% average stoichiometric quantity is used for the reaction, further experimentation is needed and will show if this is correct/useful.

>Clicky Link<








[Edited on 3-4-2009 by Chug]

I'm surprised that no one else has tried this whole batch demeth yet, c'mon lads lets be avin ya!

Only make every 3 or 4 weeks. Hope to do modified 2 stage and full demeth next WE. (Would like to get an eductor in the processor before then as well)
D ick

Chug,

Iv`e still got problems with the Venturi stopping working at the higher temps used to demeth, even on a Tam105 ( poxy thing ), any ways up it seems I could be getting a fair amount more Methanol back as I usually get around 2lts from my 10lt used.

I`m thinking of using an Aquarium pump to bubble into the Reactor under the Bio/Glyc mix and use that for demething, just making sure the outlet is away from the heater.

I can`t seem to get this link to work : http://www.biofuel-uk.net/recoverable methanol.doc

I`m doing a few tests with the Centrifuge at the moment, along the lines of testing hardwood media instead of Ecopure, will report later in a new thread..

Hi Stumpy
Link works if copied to the browse (due to space in it I think)
D ick

[Edited on 31-3-09 by <b>****</b>jotec]

I just edited the link above and it should work properly now.

When most of the methanol has been removed and the mix is thicker I get more of a gurgling sound from the vent pipe rather than the normal sucking air noise, so I think my Tam is only just keeping up enough flow for the venturi to work.

divide whatever the amount of methanol you add in proportion to the wvo

so
100L wvo with 20L meth = 20%
100L wvo with 22L meth = 22%

your 50L batch wvo with 10L meth = 20%

divide 10L by 20 to get 1% = 0.5
multiply 0.5 by 12.5 to get the average stiochiometric quantity =6.25

10L - 6.25 needed for conversion = 3.75 available to recover.
thus my arrival @ 3.75 litres for your 50L batch.
With rapeseed it allegedly uses a little less than the 12.5% average.

clear as mud now?



[Edited on 3-4-2009 by Chug]

Chug, I'm doing my second batch with the new eductor and complete demeth but I thought I'd try something a little different.
It's my normal 50ltr batch with 20% methanol giving me, as you say, 3.75ltr of recoverable methanol.
I stopped the demeth at 3ltr settled the glycerol and drained down.
I'll be demething the remaining bio today.
The reason for the change is to try to prevent mono, di and triglycerols reappearing.
The 3/27 on this batch required 5ml of bio before any dropout was visible.
I have reduce my NaOH base to 5g from 5.5g/ltr and methanol to 20% from 22%.

nice experiment Jim

was this excellent 3/27 using 5g base and 20% meth in single stage, 2 stage or modified 2 stage reaction?

keep us posted with your results.

Single stage using my hi-pressure Eductor. My next batch will be with a lye base of 4.5g/ltr and 19% methanol, full conversion in 50mins again, just love that eductor.

Demething the Bio after glyc. drain down this morning, I'm getting a steady flow from the condenser with the still head at 33c and the oil temperature at 45c.
The temperature differential is due to my relux column being fitted earlier this week. I'll post purity and temperature results later.

Ok, reclaimed methanol is 97+% pure, stillhead temperature 50c, bio temp. 78c. Recovered volume from the 10ltr used is 3.5ltr, a little less than predicted but I did remove the glycerol after 3ltr of meth had been distilled off.
The bio is now in the bubbling/settling tank and being bubbled for 2 hours, as there's next to no water to dry out, to drive of the remaining methanol.
3/27 on final bio shows no drop out and is a light golden colour, probabley due to the lack of glycerol in the sample.

Well chuffed with the result.

So possibly a drop of methanol went out in the glyc then Jim.

I'm gonna do another 135 litre batch myself over the w/end and going to use mostly recovered methanol as it came out quite high in the purity weigh in check, but I'll use 25% seeing as I'll be recovering ithe excess anyway.

Did a 100Litre batch using the modified 2 stage process followed by a whole batch demeth. 100Litres of oil and we thought 22.5 Litres of methanol with 750g NaOH.

Demething the whole batch seems to work well, the only concern being the fact we got 14.5 litres of recovered methanol

The Bio seems good with just a slightly cloudy result on a 27/3 test.
The different fractions of the recovered methanol have steadily increasing amounts of water, however this is not surprising and no effort was made to keep the methanol pure, every effort being made to demeth as quickly as possible. The temperature of the bio/glyc started around 64C and worked up to 90C for the last fraction. Just for reference, tin case anyone is interested, the fractions were:
3L 96% pure
2L 96%
2L 94%
2L 93%
2L 92%
2L 90%
1.5L 86%

All we have to do now is figure out where all the methanol came from. We seem to have got about 4 litres more than expected. 2 litres may have come at the start as we assumed the carboy had 25L in, but it loooked fuller than normal in hindsight. Looks like 1Litre of water in the methanol. We also added a few 27/3 test samples, and the remants in another carboy etc. which were not considered in the calculation as at the time the amount did not seem significant - but I suppose they could amount to a litre.

Paul

How are you testing/measuring the different amounts/fractions for purity?

I did another successful whole batch demeth yesterday, using mostly recovered methanol to start with and @ 25% instead of 22% then it's easier to divide the amount in half for the amount to recover, but I've not had chance to test it's purity yet, I had a catalogue of other errors yesterday (see bad day at the office thread) and I'm giving the garage a wide berth today!

[Edited on 5-4-2009 by Chug]

I only use virgin methanol when doing a first test run on a new idea, it reduces the variables.
Since my first total demeth, which turned out well, I've been using the reclaimed in my normal quantities, 22%.
The 22% has now been reduced to 20% and a base of 5gltr, next batch will be 19% with a 4.5g/ltr base.
The reductions are due to the use of the Eductor efficiency.

Chug,

We use a methanol hydrometer to measure the density of the methanol when it has cooled down to near the appropriate temperature iirc the hydromter is calibrated for use at 16C). The Methanol was recovered into different 2L HDPE containers (OK - 4 pint milk cartons) except the first portion which was in something else.
So quite confident about the purity or lack of it - more so than the volume measurements of what went in!

I'm a bit late jumping in on this but, doe's it/will it still work with KOH.
I'm looking at improving my reactor (when I get the time) with an eductor of jim's design (thanks mate) and simplifying things but don't really wont to be a ginepig if I can help it.

Also do you add acid or not.

Mark,

I can see no reason why this won't work with KOH, and no we are not using any acid, after reaction is complete, just crack open the venturi and start recovering, the caveat is that you need to work out how much you can recover over and above the stoichiometric amount needed for the conversion, I'm using 25% methanol now so it's simple maths to just recover half the starting amount.
I posted a guide for those using 22%
http://www.biofuel-uk.net/recoverable%20methanol.doc

I just recieved my tralles scale hydrometer in the post so I'll be able to test the purity of my recovered methanol much more accurately now.

Thanks Chug
I'll give it a go on the next batch, it will be a two stage 70/30 split (as 70% is one 25L drum and it's easy that way), I'll also try leaving the glycerol in for the second stage.

I'll post my results for all to see, good or bad.

Got an 85L batch doing the whole demeth thing right now.

Did a 2 stage, got a perfect 27/3 on the 2nd stage, so dropped the 1st stage Glyc back in, and heated to 75deg.... Methanol really flowing well into the container, gonna go check on it in a min, as left it fr the last hour... I used 18L of Meth, somewhere between 21&22% I normally get approx 2L back when demething (without the Glyc) so lets see..... Hopefully any soaps should drop straight into the Glyc as the meth has been removed??

Mike

Mike DON'T take more than 7.65ltr of methanol out, thats based that on 21.5% methanol used.

If you do you'll start to revers the reaction.



[Edited on 26-4-2009 by jamesrl]

Ok, will call a Halt @ 5L, as thats the size of my container!!!



Gotta run out to the garage NOW!

Mike

Put the 5ltr staight into you methoxide vessel, it'll be aroung the 95% pure, then distill the remaining 1.5ltr+.
The less methanol the faster the soaps drop out.

just had a go at this full batch demething malarkey.
turned out well, 80 liter batch, GL type processor 22% methanol (17.6 liter) titrated at 1.5 +5 base = 520g caustic, dewatered, single stage,passed 3/27 test,started to recover got to 6liters then panickeddidn't want to **** it up so stopped recovery ,let settle (while settle i drain pump so i have a sample approx 500ml) WOW i could see it settle took about 5 min bio Crystal clear. what a difference, doing it like this from now on so much easier
thanks chug

Cheers Jim, just checked, temp had dropped to 65, and approx 4L meth, so heated back up to 75 and will leave for 30 mins to complete the 5L, then pull off another 1.5L before allowing the Glyc to settle....

Mike

DON't let it settle overnight, due to the lack of water and methanol it'll set solid blocking everything.
I have read that KOH will set solid in the absence of methanol.

Ok - Am using NaOh, so will let it settle for an hour or so and drain, I presume the very last of the Glys will be runny as it is part of the "layer" between the Glyc and Bio?

Mike

I transfere it straight into the settling tank once I've drained the glyc. that washes the last of the glycerol out of the pipework, I hit the bubbler switch immediately. The air pump is on a timer so I just bugger off and leave it to itself.

Mike,

Glyc should be ok for an hour, maybe 2 but I wouldn't want to leave it much longer, I'd go check it now

tron

glad you liked it, I too love watching a sample and seeing the superfast glyc/soap settling

It's been settling for about 30 mins... time to put the gloves back on!!!

Mike

i clean my buckets/drums with the glycerol, i could tell that there was much more soap present than before so less in the bio

Settled Glyc, and considering I recovered 6L of meth, from the 18L originally added, was surprised to get 19L of Glyc, I presume it's soaps and crap?? Still got approx 83-84L of Bio from original 85L of oil, so yield still good! (My oil titrates around 1.2)

Anyway Bio into settling tank and bubbling, noticed ZERO froth or bubbles, unlike I normally get, so hopefully there's little if any soap in there... Timed to turn off in 3 hours, so with a bit of luck I'll be able to see to the bottom of the drum in the morning!!

Just need my bigger reactor and Eductor now, so I can do all this in one pass.....

Mike


[Edited on 26-4-2009 by GSMGuy]

when I look at the solid stuff in the cubees I can see the last portion of glyc that was drained has a much lighter layer with the soap in, and I get less soap in the bottom of my settling tank, except for a batch recently that had water in and took lots of NaOH to get a reasonable 3/27 pass, that one ended up with some right snotty soap in the bottom of the settling tank, I'm not usually too bothered about getting me hands in there but this stuff felt horrible.

Lol - I got the Bro in Law to delve into a 20L tin of settling soaps that had the lid cut off it a few weeks ago.. He wanted to clean his hands, but said it felt like flesh!


Cleaned his hands good and proper though!


Mike

could it be worth trying to demeth the bio (it is still in the reactor)?

no mine , maybe try tomorrow

If the Bio is still in the reactor, and still has the Glyc in it, then go for a whole batch de-meth - You'll get a lot more pure meth back, and the remaining sops should drop into the Glyc rather than your settling tank!

Mike

no dropped the glyc, (i panicked) leaving till t'morra may try demething the bio

most of any remaining methanol after demeth would end up in the glyc, so unless your energy to heat the bio up again is free the little methanol you would recover wouldn't be worth it, if you are worried about any residual methanol in your bio with regard to eating fuel lines/precious pump parts etc then bubble it for a few hours.

I'm glad that a few folks have been brave/crazy enough to follow my wild notion and give this experiment a go against all the stuff that is written about reversing the reaction, and thus far it seems the experiment is working well, BUT we should start to get a little more scientific and make sure we are doing shake up water test to check for di and mono glycerides, on settled bio after a 3/27 pass, but before total batch demeth, and then do the test again after demeth.

ok going to be a bit braver/ scientific next time, now i know it works

Having a "Stock up" so now got 3rd batch on 2nd stage, and will whole batch demeth this one too - Prev 2 batches, after a 3 hour bubble have been crystal clear to the bottom of the tank after 8 hours or so, passing water test perfectly, and with only a very small amount of soap and glyc on the bottom of the settling tank

Just need my bogger processor and eductor now!

Mike

I've just made a batch but have now ran out of time to do any sort of de-mething. Having done a 2 stage and passed the 27/3 I've now closed the system down to continue it tomorrow when I get back from work.

The glyc from stage one is still in the glyc collection vessel and I'll put this back in tomorrow and do a full batch de-meth and let you all know my results.

Nige

I've just started the processor up again for whole batch demething and I was wondering if anybody knows what sort of volume of meth I can expect to extract.

I used 9lt of methanol in 43lt of oil. The 27/3 is a pass.

Thanks in advance.

Nige

chug did a table for the recovery amounts http://www.biofuel-uk.net/recoverable%20methanol.doc

Thanks for that Tron. Missed that post!


And thanks to you Chug. Nice to have tables for comparisons. Great work.

Nige

Well, I'm a bit disappointed with my results tonight. Of the 3.8lts available to recover I only managed to get out 1.5lts in 4hrs. I haven't the time to see this through to completion so I've bombed out. I've added some prewash water and I'm going to finish the batch like I normally do...by bubble washing.

I can see a few issues with my plant..namely the condensor isn't as efficient as I would hope and my venturi is not as good as it could be. However, with the new JRL50 in my posession, a new JRL inspired cast venturi and the JRL eductor my new plant should be up to the mark to try this idea again in the near future.

I'm not giving up just putting things on hold.

Nige

Nige - sounds like it could be your condensor as stated - I had no probs getting 6L out of an 85L batch (I normally get 2L tops when prewashing)

Stick with it, I've had excellent results, just need a bigger processor and the magic Eductor!!!

Mike

Unlike poor old Nige I've just finnished a batch, the best yet using full batch demeth.
50ltr, titrated at 1.56 + 5.5 base and 20% methanol giving me a return of 3.75ltr when distilling. The reaction went as usual, 50mins for a fantastic 3/27 pass, using the eductor, of course.
This time I stopped 200ml short of the calculated quantity for demeth, the reason being I had a small reverse reaction last time.
The 3/27 after demething was even better than the fifst one, probabley because there was no glycerol in it.

Due to the time saved with eductor and demeth method I can do 2 batches in a day, no probs.

Long live the whole batch demeth.

sorry to hear things didn't work out so well with your setup Nige, your new setup from Jim will get you sorted.

And great to hear you like it too Mike.

Can I ask again that anyone doing the whole batch demeth takes a sample after passing 3/27 test but before starting to demeth and do the shake up test with water to check for any unreacted material, and then do the same test again after the whole batch demeth, if we have no unreacted material in the first test and none in the 2nd then it's a pretty good indication that we have no reversal of reaction.

A PHlip test would be another way of checking but the test is not available here in the UK yet, I've contacted the US supplier and it seems to work out about £4 per test, but I'm waiting to confirm postal costs.
http://www.phliptest.com/products.htm

I'm going to be brave and try Chugs process (modified 2 stage and full batch demeth) on a full 300 litre batch - that should be a good test for it.
I will let you know how I get on.

According to Chugs table I should be looking at around 27 litres of meth recovered which will be nice.

I will be interested to hear how much meth you get back per hour.
What is the heat input, what is the power (LPM ) of the pump and how big / cold is the condenser.
D ick

The heater is 3KW, the pump is 82lpm.
The condensor is 1200mm long and made from 22mm pipe inside a 28mm jacket. It is extremely cold, around 4C as the coolant is chilled by a beer chiller as used in pub bars.

At this very moment I am demething 300 litres of glycerol and have a continuous trickle of methanol (not just drips) coming out of the condensor.

After doing some glycerol demething and testing the purity of said methanol, it's not worth the effort unless you have a good reflux still head, I doubt you'll get much better than 80% pure, 20% water without one.
Would you use oil with that much water in it? No, I thought not.

[Edited on 30-4-2009 by jamesrl]

Jim,

is this low purity meth recovered from just glyc?
or from a whole batch?
did it have any pre-wash water in?

I've only managed to test one lot from a whole batch demeth and I know there was water in the wvo to start with in that batch but my new hydrometer toy reads out at just over 93%

I should have been a little clearer.
I was refering to glycerol drained down from prewashed batches.

My whole batch demeth is returning a steady 97%, according to my low surface tention Hydrometer but my oil is quite dry.

I dont prewash, and my oil is heated and settled before being processed so there really shouldn't be much water in the glycerol, therefore it will hopefully be quite pure.
I haven't got a magic tralles hydrometer yet (Chug where did you get yours?).

I dont have a reflux head but my still head is controlled by a PID and maintains a good constant temp (currently set for 65C).

I'm only demething the glyc as I have best part of 400 litres of the stuff laying around so I thought I'd try to get the meth back from it. That will have a double benefit as it will also reduce the volume of glyc I have to get rid of.
As of next batch I will be trying the whole batch demeth.

By the way Jim, your venturi seems to pull a decent vacuum even when circulating glycerol, not quite as good as with oil and far less than with bio but still pretty good. I think the reduced flowrate from the pump when moving glyc has something to do with that.

Jim,

ah pre-wash in glyc explains it, I thought you meant from whole batch demeth.


Jules,
fleabay

>one here on fleabay for £5<

>one here for £8<

>one here for ? in dollars<

Chug ...

Absolutely brilliant .... Demething my first "whole batch demeth" at the moment. Just collected enough distillate to test and got an SG of 0.802 @12.6ºC on a hydrometer calibrated @15.6ºC. This is better than 98% purity according to the chart I have.

I normally do a 5-7% pre-wash and I'd started making a reflux column to try and improve the estimated mid 80s% purity I was getting (hydrometer is 0.8 - 0.75 @ 15.6ºC and the reading was off the scale!) but I'm now wondering if the column is worth pursuing provided all the soap drops out. Guess it's pretty elementary (having a why didn't I think of that moment!)... if you have dry oil, very pure Methanol and don't add any water (other than that created in mixing Methoxide) There's not a lot to contaminate the recovered Methanol.

Not with standing the above, the time and energy saving is enormous and so far no foaming which was a big problem for me when processing stored glycerol ... Deep respect to you Sir for thinking outside the box.

Once I've finished the demeth and bubbled out the residual Methanol I'll post regarding the soap test.

Thanks for sharing.

Julian

Thanks Chug, I think I will get one and have a play.

The processor is loaded with 300 litres of oil and currently is drying the oil - today will be my test of your complete method - fingers crossed.

Well the big batch is finished and in the settling tanks. Overall I was very please with the result.

300 litres of oil, titrated at 2.4
Heated up to 75C when dewatering the allowed it to cool back to 60C.
60 litres of methanol (30litres new, 30 recovered) and 3kg of KOH.
Two hours mixing with first 75% then immediately added the other 25%. Another two hours mixing then took a sample.

It settled pretty quickly and a 27/3 of the clear bio gave a reasonable, just slightly hazy pass.
Then demethed the whole lot and recovered 20 litres of methanol. Stoichiometric ratio of 12.5% means I should have used 37.5 litres of my 60 for reaction allowing 22.5 to be recovered so I was pretty happy with 20 for my first go.
There was still meth dribbling from the condensor and the oil was only at 78C but the ******* BES thermostat kept tripping its reset button in the inline heater. I may need to do something about that if I'm ever going to get near a final oil temp nearing 90C.

The methanol was crystal clear.

Left to settle for an hour then drained the glycerol, 42.5 litres and much darker and thicker than usual, even though it was 77C when draining. It will be interesting to see it when its back to room temp.

All the bio is now in the settling tanks awaiting its soap to drop out.

27/3 test of the finished fuel gave identical result to that before demething so it doesn't look like any significant reverse reaction has occurred and a 50/50 shake up showed two layers only, bio on top and slighlty soapy water on the bottom. It was easy to see through the water layer so there can only be a tiny amount of soap in there.

All I can say is well done Chug, you seem to have revolutionised the process and saved both time and money. Not having to reheat the batch from periods of cooling must save a fair bit of power.

The whole process took 14hrs start to finish from room temp oil to settling fuel, and three hrs of that was getting it hot enough. For four hrs of the process the heater was off (during mixing) and it was under PID control for the rest of the time. For one hr everything was off whist the glyc settled.

Well my piping hot gyc has now cooled to room temp and is a lot thicker than the stuff I used to get and there is a definite soapy crust on the top of it.

Also, after settling for 12 hrs so far, there is very little soap in the bottom of my settling tanks, prior to this method there was far more in them.

Just a thought - would it be worth an experiment to check if reverse reaction does occur.

Could we start with a sample of known high quality bio, mix it with some glycerol (with varying amounts of meth still in it I suppose to account for conditions throughout the demeth process) and then heat and mix it.
We could then find out if the bio and glyc settle out and the bio is still high quality, or if some of the mixture turns back to glycerides.
Just a thought, I'm sure someone of your vision Chug could sort something out.

I have thought of doing my best to reverse the reaction but I'm so pleased with this method and other experienced brewers results that I don't think it's necessary.

I don't believe you are likely to be making triglycerides in any great quantity and I think the 3/27 test is good enough to check for triglycerides. Also a clear 'shake em up with water' test before and after demeth is good enough for me.

I've asked some of the Americans with pHlip test vials to try it my whole batch demeth method and test the bio afterwards with pHlip vials but so far none have.

Some samples I've kept from my first few batches show no signs of bacterial growth, I know it's only a month and a half but I want to know if there is any chance of this happening over time in folks fuel tanks.

Chug ...

Further to above post.

I have been using the two stage process for the last four batches and getting consistently good 3/27 passes (or in my case 1/9 as I have 15ml pointy bottomed test tubes which reveal even the smallest drop out. Really great bits of kit bar the fact they are a plastic which seems to be attacked by Methanol and disintegrate after a few tests!) As I started the batch at 7:45 pm I opted for a single stage and got a 1/9 pass on a sample taken after one hour but tested at 9:10 pm once Glycerine had settled. Started demething at 9:20 pm. As above, tested Methanol purity as soon as enough was collected and got 98+%. Tested again at 10:20 pm with the same result. During this time the condenser head was controlled to a constant 63ºC with the processor tank at around 67 - 69ºC.

My Methanol recovery rate seems to be very slow ( I've got 21 items on my "to do" list to try and improve things!) so continued into the small hours ...

11:58 pm 1/9 test passed.
12:50 am increased condenser head temp. to 65ºC to try and speed things along (probably should have left things alone so not too many variables, but I wanted to go to bed)
1:20 am 1/9 test showed possible signs of drop out but nothing I would normally worry about.
2:00 am still distilling Methanol at a reasonable rate (starting to curse your good idea by this stage) tested Methanol purity and got 95% so decided to call it a day. Tank temp now 74ºC. Estimate circa 4.5 - 5 litres Methanol recovered.
3:45 am drained Glycerine and bio pumped to settling tank. Bubbled over night (what was left of it)

1/9 test on bubbled and settled bio showed a small dropout. Shake 'em up test showed no signs of soap but a very thin "scum" layer between bio and water was evident. Guess this what Graham was referring to earlier in the thread. It would seem that I've experienced some reverse reaction probably due to the length of time taken to de-meth. Glycerine has set to the consistency of cold butter.

I'll certainly give this method another go. I'll try your modified 2 stage reaction and start at a sensible time.

I'll keep you posted.

Julian

Julian

it seems like you spent a long time demething just for 5 litres.
I would expect to recover that in an hour!
I think the quicker the whole batch demeth is done the better.
You need to get those 21 things done.

What was your amount of wvo and how much methoxide did you use?

If you had a clear passes on first two 3/27's and then later you have slight fallout on the 3/27 then this sems to indicate some back reaction, backed up by the Dreaded White Stuff(DWS) of mono and di'glycs at the water/bio interface in the shake em up test, next time also do a shake em up test before starting demething, so you know whether or not it had the DWS present before you started demething.

I seem to get 5 to 6 litres per hour out of my condensor, took about 4 hrs to get 20 litres.
This seems to be a common figure for various people on here, I wonder if there is some limiting factor for this.

Looking forward to getting enough oil together to make another batch. Might need to get a better thermostat in the heater though that doesn't trip as quickly. It took me a while to work out why the oil wasn't getting any hotter, only worked it out when I realised the heater SSR was cold, it normally runs warm to the touch when heating.

Hmm,--

Do I? or dont I?--Ive been really happy with the modded 2-stage, and great easy settling of soaps the next day.......

I have 100 litres I dried today and need to react tomorrow or I'll have no fuel this weekend,--Had to buy bloody diesel last week--don't want to go There again!...

Had a chat with Jim (Jamesrl) this week, and he was well impressed with this method. I haven't tried it yet, due to my limited time and the reactor really only will contain around 130 litres before possibilities of soaps down the condenser--Guess I could drain a bit till later.....


Gotta try it haven't I!

Chug ...

Agree with all your comments and will try a "shake 'em up" test prior to demething on the next batch. Luckily much of the demething was done on economy 7!

Oil qty = 80 litres, Methanol qty = 15 litres.

I think the slow demething is probably due to too much resistance in the vapour circuit. On a closed valve my venturi pulls a vacuum of 6"hg from a Leo pump running at 14 psi and 35 l/min. Can anyone confirm if this is a reasonable performance? Assuming this is satisfactory then I think my problems are one or all of the following:

Vapour circuit is 15mm dia and needs increasing to 22mm.

GL's "plumbers delight" is a great idea but I suspect it may present quite a high resistance especially when condensing. The way I have it configured probably compounds the problems in that it's at an angle of 45º and around 1200mm long which I now feel is over kill. I'd concur with julesandtash that a multi core design may be better, perhaps with a plenum at the end to allow easy egress of the Methanol.

Too smaller delivery hose into the Methanol recovery pot. It's 8mm silicon tube used because of it's flexibility and because I had it to hand. I've added a vent line to the top of the pot from near the venturi via a needle valve so it pulls the methanol into the pot. System seems to work OK but I'm obviously loosing a small portion of the flow through the condenser.

Any comments or suggestions welcome.

Julian

Alistair, Yes.

Julian
my pipework on the vapour side is all 15mm, but do I read that you have your condensor at 45°?

If so, first why?
and second (maybe answered by no 1) cant you try it vertical?

I haven't got a vaccum gaugue or any mercury so can't give you a mercury vacuum figure but my venturi will pull at least 7 feet (84 inches) of water as I've tested it. Thats at 82lpm from a TMP130.

My vapour circuit is 22mm to the outlet below the condensor then 1/2" braided tube to the venturi.

Condensor is a plumbers delight but 22mm inside 28mm. It is just shy of a metre long and vertical. It is also kept very cold by the beer chiller.

Jules, your venturi will pull 16ft with your pump, no problem.

All my vac-pipe to venturi is only 8mm. It has various taps etc for meth and directing 'flow' to condenser....

Well, whole-batch de-meth underway. Just finished reaction stage, which gives me a 'just pass' 27/3 --just a tad cloudy NO drop-out after 10 mins 20deg C

(No 'pre-wash' done....)

I'm at 71 degrees at this time, and can see loads of MeOH from condenser--MUCH more than if de-mething just the fuel--Currently, have no accurate way of testing purity....

We see how it goes....

I'll 27/3 test fuel after an hour and then again an hour after that....

Alistair,

did you do a shake em up test after reaction and before demething? and do one after demething too

Yes the meth flow from glyc or whole batch is much faster than the piddly little bit you can recover from just bio alone.

I would work on stoichiometric amounts to work out how much can safely be recovered rather than leaving it an hour in between, or it may reverse.


>rough guide here<

Hi Chug!

No, Didnt do the shake-um-up before de-meth--Would have thought there would have been soap there anyway--Why do you ask?...

But, Here's summit interesting...

I 27/3 tested after an hour of de-meth, and had again a 'just-pass' condition--no drop-out, Just cloudy mixture...

Just did another at the 2.5 hour mark of de-meth time, and it gives a 'Instant-Clarity' result--Even when 10mL of BioDiesel have been added to the meth....

So the reaction has gone Forward and Not back--Which is sorta 'Wrong....'

(This batch did summit 'Odd' anyway. On adding the 80% methoxide as in Modded 2-base, temp was at my normal 61 degrees...

It quickly climbed to 69-70 degrees and held this temp with heater off....

On adding the 20% later on, temp fell to 67 and stayed there till I started the de-meth phase)

In total, I have recovered 6.7 litres MeOH so far, I used around 20L for the initial reaction of 100Litres....

Its at the mo, settling ready to drain glyc. There was still a dribble of MeOH from condenser, but time is getting on and I would like to see how much if any I get if I continue to de-meth fuel after glyc. draining...

Result--So Far, Very good!

Shake em up before demeth will have soap but should also show up DWS of mono and di glycs, so that we know whether they were present or not before the demeth and not just appearing after as a result of reversal.


Could have got a little more meth back before stoichiometric quantity reached, but try a shake em up after draining glyc but before you continue demething just the bio, and then do another shake em up at the end of demeth.

[Edited on 7-5-2009 by Chug]

I always get a better 3/27 result after demething.
You must remember that until you reach the stoichiometric measure there's an excess of methanol in the reactor. We use an excess to push the reaction, so whilst demething, the reaction will continue to completion, providing the titration was spot on and the oil dry.
I now leave approx. 200ml in the bio just to reassure myself I haven't gone too far with the demeth.

You only need 1ft of condenser (Plumber's delight) for every Kw of heat.
As most of us use 3Kw heaters a 3ft/1m condenser is enough to do the job.

jamesrl ...

Hi.
Yes, I read that on GL's site last night but I can't see the logic in the statement. Surely the power of the heater is only relevant to the time taken to start evaporating Methanol, after that it's just "trickling" heat in, well under it's full capacity, to maintain the condenser head temp.

I'd have thought inlet temp and flow rate of the cooling water and vapour flow rate would be far more pertinent but way beyond my calculation capabilities.

Have you any idea why it's a ft/Kw?

Julian

Julian
Interesting your condenser is at an angle and not working well. Mine is also more than 1m long and at an angle and not working well.
I had decided to move it before the next batch anyway but this could be a pointer.
As a matter of interest how is the bio returned to your processor? Does it enter and hit the processor wall or enter downwards into the surface of the bio? From reading posts most who seem to be getting good demeth rates have it hitting the side of the processor and, I think, therefore making a big splash and releasing the meth vapour faster. I have fitted a diffuser into my processor to cause the same effect (hopefully!)
D ick

D ick ...

On my processor the oil return is diametrically opposite the vapour outlet (existing fittings on the tank) so I opted to put a swept bend inside the tank rather than run the risk of squirting liquid into the vapour circuit. Diffuser sounds like an interesting idea. Presumably it's a horizontal inlet pipe hitting a plate spaced off it's end so the flow is diverted vertically for 360º. Like to see a picture or sketch if you have one. Have you run without this device to enable a comparison?

Julian

Is there an optimum vapour flow rate through the condenser? I'm sure there must be.
What kind of position do you guys run your venturi valves at when demething. I ran with mine fully open last batch but I noticed that the return line to the venturi from the condenser was a little warm. I presume if the condenser was working at full efficiency then the gas coming out to the venturi would be cold.

D ick, it'd be better to have your defuser the other way up like a spoon with the bulge upwards, as it is you're likely to send a pressure wave back down the pipe and kill the venturi stone dead.
To create the desired spray needs energy and it can only come from the pump so the output pressure will have to increase to do it.
The backpressure from the dish is the problem.

On my reactor the return outlet from venturi inside tank has a 22mm elbow set at 45 degrees or so directed Away from the vapour outlet to the condenser. The pipe from venturi extends right across the tank and is very close to the opposite side of where it enters... At this point is where the condenser outlet is. However, this outlet is piped Up into the void area at the rim of the inverted H.W. cylinder, and has an elbow pointing roughly downwards at the highest point in that rim area--IF you know what I mean....

Works well. I positioned things this way when on first run I found I had soap-suds etc coming from condenser when it was near fully de-methed and a very soapy batch was made that caused excess foaming to cause the stuff to be ejected from condenser....

Jim,
I have tried the venturi with the diffuser fitted with cold oil and it is still pulling the same on the vacuum gauge as before. I put the upward cone to, hopefully, reduce the pressure wave but I will bear it in mind it is easy to change if necessary.

Julian,
There there is a pic previously on this post but I want to try it before making comment because as Jim points out it may not work!

D ick

Great to hear it's working in trials. I have a vacuum guage myself but I've never fitted or used it, I work on the basis of "it does or doesn't work". Having made and fitted the best part of a tidy few venturis, after spending months researching, designing, redesigning and testing various configurations with various pumps, I can now just look at a venturi and tell if it will work in a particular situation.
The diffuser is a new concept in the quest for better brewing, I was perhaps a little over cautious about the effect on the venturi.

Jim
Time will tell when it is up to temp.
From my limited experience the viscosity has a big effect on the draw. It may well be that where I was getting a good vac before the lower viscosity will cause a higher 'back pressure' and kill it.
If I was to make another processor I would fit the venturi so the exit was going across the barrel rather than down it. I could then direct the flow onto the side.
I live and learn! (and enjoy experimenting)
D ick

Chug,
I know about the formation of DWS (where it comes from) but what is the implication of using bio that has this in it in an engine? What is damaged by it?

D ick

D ick

Graham summed it up nicely in his post above so I quote.
DWS can cause an increase in absorbtion of water into the biodiesel, which may increase the risk of bacterial growth, plus increased viscosity which may be an issue in winter, plus an increased tendency to experience waxing in cold weather.


[Edited on 8-5-2009 by Chug]

Chug,
Thanks for that I had missed GL's post on the effects.
It may be beneficial to use some biocide every few tanks?
D ick

Jules ...

This was what I was eluding to several posts up. If you are drawing vapour into the condenser at 65ºC (I try and use a tad under that) I believe you only need to condense the majority of the Methanol, probably impossible to grab every last drop, so with a limited knowledge of physics and an inapt ability at mathematics (how I wish I'd paid more attention at school) I would venture a guess at a vapour exit temperature of 10-20ºC as being adequate.

With my apparently lazy vapour circuit I always get a very cold exit temperature with the smallest flow of cooling water and the vapour circuit on full bore. In comparison your system sound like it's on steroids but by adjusting the water flow/temperature and the vapour flow you ought to be able to control the exit temp from the condenser. I promise I'm not "Graham bashing" here (I think he's an absolute genius and I have immense respect for his inventiveness) but I would think that condenser length must also come into the equation. A higher cooling water temperature can surely be compensated for by a longer condenser and conversely highly chilled water could accommodate a shorter condenser.

However to answer your question fully I recon you need someone with more brain power and knowledge than me to calculate the optimum, economical exit temp.

While on the subject of flow rates etc, some years ago I worked on Inert Gas systems fitted to oil tankers. I can't remember any figures but careful attention was always paid to flow rates of both oil and gas to prevent static build up with consequential disastrous results. I think the velocities we pump and suck at (sounds a little obscene ... sorry) are well below dangerous levels but has any one put any thought into possible problem?

Julian

I can change the effectiveness of my setup by increasing or decreasing the water flow through the condensor, and it does seem best when the head of the condensor is kept around 65 -70°C, too much water flowing slowly cools it below 65°C, and not enough flow and it slowly creeps up over 70°

I usually have the venturi valve about 1/2 - 2/3rds way open for the first half (approx 1.5 hours) of the demething stage and then open it fully for the last half as the glyc thickens up.

perhaps an insulating section of pipe between the still head and the condenser would allow for a faster flow of vapour while not affecting the temp of the still head, this could give a faster de-meth with less energy needed.

High Compression II ...

Top of my tank is extremely well insulated with about three inches of polyurethane squirty foam, so no problem there but I think you're right regarding the vapour circuit. I was going to rearrange the plumbing to put my condenser vertical but it would have meant too much dismantling, so I made a new one without squishing the vapour tube so very little resistance. The new condenser is connected to the processor by around 1m of pipe and during dewatering this afternoon, the tank temp reached 102ºC to achieve 55ºC at the condenser head. With the previous set up I usually had a 10 -15ºC difference between tank and condenser head. I think the most likely cause now is the venturi not creating enough flow.

I'll carry on with a whole batch demeth tomorrow doing a shake 'em up test as soon as I get a 3/27 pass and see how long the demethnig takes. It will be interesting to see if the additional length of pipe prior to the condenser provides any reflux and improves Methanol purity. Meanwhile I think I'll start work on a new venturi!

Julian

It will surely depend on what the processor sits on as well. Mine is stainless steel and sits on a concrete floor. Not a great electrical earth for the mains etc but I'm sure static would still track to ground through that. Mind you, all the pipework is steel and the pump, heater and control panel have connections to mains electrical earth.
Same with the oil tank.

What I have done is link the processor and oil tank with an earth bond as they are linked by a flexible braided 1" hose not a solid steel connection.

Bio-Rich--


............"The new condenser is connected to the processor by around 1m of pipe ..................

Is this the 'still-head' pipe,--The vapour outlet to be condensed?

On my system, this pipe is only around 3-4 inches long, done in 15mm copper, via a couple of elbows.....

Mine is about 18 inches (450mm) from the centre of the processor top dome to the condensor inlet - 22mm and wrapped in two layers of camping mat and two layers of aluminium bubble wrap insulation.
Its only that long as the processor is 760mm diameter.

[Edited on 10-5-2009 by julesandtash]

Chug, and everyone...

Would it be an idea to split this thread, as there's loads of side-discussions on effectiveness of Condensers and the way that systems have been set up, rather than the actual discussion of the 'Full Batch De-Meth' as in the title..?

What do you guys think...?

Sounds a great idea to me .

Go for it
D ick

High Compression II ...

Yes, that's right. I know it's probably too long unless you pretend it's a reflux column, but this was only an experiment to try and put my condenser vertical. My "refinery" is really tight for space and this was the closest I could get it without a major rebuild. Despite the arrangement I think it's revealed my problem, so a new venturi is in the making, I'm having a whirl at spinning one (pun intended) rather than one cobbled together from fittings as before. If it works ok I'll may try it with both condenser arrangements but most likely revert to my original angled plumbers delight which has about 2" between it and the tank.

I put a little plenum on the end of the temporary condenser which seems to have stopped the gurgling noise that used to come from the vent outside so I may retain this idea.

Julian

yup, I'll split it out later...

Hectic here at the mo....

Well, I'm converted.......

.... my early experiments were disappointing. I got a large amount of soap and 3/27 fail or marginal. I know now that it was because I did a water prewash after the initial whole batch demeth in an attempt to reduce the soap..... duh...

.... Later trials, which omitted the 5% water prewash, were much better soapwise but I still wasn't getting a totally satisfactory 3/27 after a 2 hour, single stage reaction... So I started playing with the reactant quantities.....

... For the last batch, I used 85 litres well dried oil, 18 litres methanol and 600g NaOH. Reacted for two hours at 63*C , then immediately demethed (reactor kept at 68-70*C) for 1 hour only. Settle for 1 hour and drop the glyc. Continue demething the raw bio for a further 2 hours (finishing temp - 85*C), then into the settling tank and bubble for 3 hours.

3/27 was spot on - I actually do a 1/9 and this was instantly clear so I added another 1ml bio (equivalent to 6/27) Still perfectly clear with no fallout whatsoever.... so satisfying when that happens ain't it?...... Purity of recovered methanol was better than 97% - that's good enough for me.

The only slight downside, I think my yield is slightly lower. It's only by a couple of litres and is more than compensated for by the easier process, the reduction in soap and the value of the recovered methanol.....

In conclusion, (using a single stage process) I think there is a small reverse reaction if you use standard reagent quantities - you need to up them slightly. I didn't attempt to recover all the meth but I'm more than happy with what I did get (quantity and quality) with my standard GL with no reflux. The soap that ends up in the settling tank is a much smaller quantity, most drops out in the glyc.

So, thanks Chug - I'm a disciple. Praise be to Chug!

Nick

thanks for the kind words Nick, and good to hear you are getting to grips with it now mate, as you've found the prewash is just not needed, most of the the soap just drops out with the glyc.

But I'm not sure why you say to use extra chemicals though?

I would have thought it's more down to agitation. I find single stage is harder to reach 3/27 pass unless it's good wvo, or longer mixing time, or you have a monster pump or eductor.
But once a 3/27 pass is reached, by whatever method, as long as you don't recover too much methanol it should be fine,

Jim, myself and others have been having brilliant results working on the basis of only recovering down to a stiochiometric quantity of 12.5%

I see you used a slightly different approach with only demething the whole batch for an hour, and then draining off the glyc.
What was the thinking behind this, still worried about reversal eh?

I would be interested to know the amount of meth you reclaimed? there was possibly just over 7 litres from the original 18?

I just did another modified two stage with full batch demeth.
For some reason, no matter how long I mixed for, I ended up mixing stage 2 for 2 1/2hrs I couldn't get a perfect 27/3 pass. As neither of my vehicles are that modern and not common rail I decided to live with the tiny (about 1/4ml pulled out with a pipette) amount of fallout and demethed it all.
Got back 20 litres of my original 60 which I was happy with, I left it demething whilst I went out for an Indian. Took around 5hrs to get all that meth out.

27/3 on the finished fuel was no worse than that before I started demething so back reaction didn't seem to be a problem even with less than perfect fuel.

I only use 20% methanol and if I do a true two stage I get perfect conversion. I wonder if maybe I should up the meth a bit (as I will get it back anyway) for the modified two stage?
I know an eductor would be a good investment but that will involve some reworking of the plumbing and welding in a second socket to the top of the machine. I wont be popular spending more pennies on it at the moment so if I can guarantee a good pass on modified two stage by tweaking the chemicals instead that would be more beneficial to my marriage

Any suggestions?

I got Balls in mine!

Here's a strange 'after-effect' of the whole-batch de-meth....

Did the reaction, 110 litres oil, tit 2, 24 litres virgin MeOH, 900 grams NaOH,(rounded up from 880) Modded 2-base,m Loverly 27/3 pass at reaction end and de-meth end--didnt try the DWS test, everything looked just great...

(Although I also suffered a poor yield, Dropped around 15 litres...)

Recovered approaching 10 litres in around 2.5 hours, settled, drained glyc, and then dried/de-methed remaining fuel only for a further hour, Just to make sure...

Pumped out, settled overnight, still Very slightly hazy/cloudy, and left for a day or so longer....The glyc. drained was solid 24 hours after draining-this was expected--recovered a litre or so of cloudy fuel from solid glyc to add to next reaction

Now the fuel in settling-drum after 3 days was stone-cold and perfectly clear, so pumped out through filters as normal, and WAS sparkling-clear. Put 50 litres into 300D and 25 litres into container for 190....

Checked engine-oil on 300D a couple of days later, and noticed fuel-filter (pre-filter plastic thing-you know the ones...) and fuel is like orange-juice, completely opaque.....

Checked 25 litres in container, this was a little better Until shaken up. It also looks like orange-juice--Seems summit is settling out later on, -just like a Very Fine silt or summit like that, but fine enough to pass the 10 mic, filter on 300D ...

300D has been running fine, no signs of filter issues at all....

The settling-drum has the remains of the batch, which has what looks like millions of tiny balls in,--These appeared After pumping out post 3 day settling--
as well as the soaps in the very bottom which set-solid like glyc......

These tiny whitish balls have coated the sides of the drum. They are waxy in texture and will not dissolve in the fuel--Guess these are soaps--Strange thing is, They also appeared a few days After pumping out the 75 litres of fuel from settling-drum, They were Not there when the fuel was pumped out...

Strange!

[Edited on 19-5-2009 by High Compression II]

Alastair,

Your deskription sounds exactly the same as the result we had.

I shared the batch with my father who infomrs me that warming the bio gets the solids to dissolve, or adding 10% petrol does (might work with less - not tried).

We put it down to longer chain oil in the stuff we used just dropping out like it does in winter - though we were not totally convinced we have not investigated further. We used only liquid oil for the batch which was dried first and titrated at 1 - whereas normally we include an amount of semi-solid or solid oil.

Have you tried warming any, or adding any petrol to see what happens?

It blocked my filter when I first tried pumping it into the car, so I stopped and have had it settling for a further 2 weeks with little change other than all the solids not appear to have sunk.
I am planning on looking at it tomorrow.

Hi Countrypaul....

Glad it wasnt just me then!--Must be summit we are not removing due to the 'no-pre-wash' of this method--but doesnt explain others apparent success....

I have the dregs from the settling-barrel in a cubee for experimenting and I have the 25 litres not used yet....

I'll try some messing round if I get time tomorrow, see what a little heat does etc.
My oil was also 100% liquid and very nearly completely clear WVO that was de-watered in the GL overnight by venturi so was pretty bone-dry....
I was thinking of trying again the whole-batch de-meth, but just before settling and after de-mething, do the pre-wash. I tried a test-1 litre of this the last time and it didnt look as though it would have gone wrong, but did not apply it to the actual batch...

Both times I have done this whole-batch de-meth I have had the same sort of issue,although first time round, not so severe, with regards fuel clarity after storing I had the Balls both times however ....

Paul- My dregs also contain a large amount of Balls, and they are apparently the very close to the same SG as the fuel--They float around for the most part and dont settle...
Will filter some off and mess around....

[Edited on 19-5-2009 by High Compression II]

I made a batch yesterday (45mins) and did a 5/45, just a bigger version of the 3/27, after demething the whole batch and it dropped out tiny blobbs. I tapped the measuring cylinder to get them all together expecting one larger blob to form but it didn't, it now looks like a 3mm ball of brown cottonwool.
The oil is from a chinese place, thick liquid and black as your hat, just wondering if its something they coat various foostuffs in, the 5/45 is crystal clear as is the bio

Good idea with the prewash Alistair, I'll be making another batch tomorrow so I'll give it a go.

I have done 2 batches of 160L with the whole batch demeth.
On the first I did a prewash, all was fine, on the second i did no prewash. The bio was again fine.
I have filtered from the settling tank today and it was crystal before filtering and after.It has been settling for about 3 weeks.
I will do another batch on Saturday and report back (looking for balls!!)
D ick

No weird tiny balls here, usually crystal clear after settling and filtering, even after a week or so in a cubee.

I did have some weird white balls stuk to the sides and bottom of my old burco boiler processor a few years back, which I decide were high melting piont esters as they were ok when warmed up.

I'm looking forward to your further investigations into these tiny white balls.

My settled soap is usually a thin runny/slimy top layer (a bit like egg white but orangish!) over a thicker solid lower layer with some glyc in the very bottom centre around the drain outlet.

OH and please folks can you do a shake em up test before and after whole batch demeth, please, please?

[Edited on 19-5-2009 by Chug]

I think "The Balls" may be a result of reverse reaction due to removing to much methanol of the whole batch. The cloudiness after settling and filtration sounds like water absorption due to the presence of mono and diglycerides....

Read THIS ARTICLE which explains this in some detail......

I stopped my methanol recovery well short of the maximum possible and I have no balls....... (oo-er)

Nick

Whoops...

I have checked back on the notes for the last batch - and it was a conventional 2 stage process - that is the glyc was dropped before the demeth.

So we have the same apparent symptoms but produced via differenet processes.

I'm wondering if it is just some longer chain esters after all, or could it even be FFA that is precipitating?

Chug
Doing shake test before and after demeth. Some DWS after.
After 24hrs settling getting slight DWS on top of clear water after 30 mins.
I leave the test on the bench for a week or so and the DWS becomes less but the water slightly cloudy.
After settling for 3 weeks but before filtering only very slight DWS.

Am I really seeing DWS? I am assuming that it is the very thin, white interface layer between oil and water?

This part of the above article could explain what is being seen? Does it mean that certain oil stocks are more prone to it?
Would a modification to the process to be to take less meth from the whole batch, settle then finally totally demeth just the bio?

(quote) However, von Wedel says [] “There are other molecules, other dark Darth-Vader-type creatures that inhabit the fuel,” he says. The mysterious residents in biodiesel that von Wedel refers to are sterols, which are complex aromatic ring structures like cholesterol. “They are found in very low concentrations in all vegetable oils, and they can interact with traces of impurities in biodiesel,”

Dr. Fischer’s hypothesis, which suggests these sterols may aggregate into complexes with monoglycerides and diglycerides present in biodiesel, helping to form a precipitate that falls out of solution. “What it does is amplifies what used to be just a residual trace amount of a [monoglyceride anddiglyceride], and they will suddenly form precipitates under certain conditions,”

He adds that moisture in the headspace of railcars shipping B100, combined with shipping time, could explain why B100 might look good leaving the plant but turbid once the biodiesel is ready for unloading. This exposure to “cool, moist air” ought not to be confused with gelling related to cold flow though. After on-spec biodiesel gels at any given temperature, it should be “reanimated” in its entirety once it warms back up. “Gelling is a reversible phenomenon,” von Wedel confirms. “We’re talking about a precipitate that doesn’t go back into solution, which ends up clogging filters as it did in Minnesota, in Washington and, of course, here in California.”

monoglycerides and diglycerides are hydrophilic. “This does not mean they dissolve in water, but they will interact with water,” he says. Monoglycerides and diglycerides are amphoteric, meaning the alcohol “head” of the long chain likes to stay in water, while the “tail” of 18 or so carbon atoms prefer to remain in the fuel, von Wedel tells Biodiesel Magazine.

PS Any news on the phLip tests Chug?
D ick

[Edited on 20-5-09 by <b>****</b>jotec]

An article on STEROL GLUCOSIDES may also be of interest.....

Cheers

Nick

My fluffy cottonwool only appears in the post demeth 3/27.
I'll do a shakem'up before and after filtering the fuel through Ecopure.

How about some pics of the balls/cotton wool etc?

Cheers

Nick

Apart from the first couple of whole batch demeths which showed traces of DWS on the shake em up test, I've got nothing but good words about the results, it's quicker than demething bio and glyc seperately, and thus less energy is used, no messing about with water for prewash, superfast glyc/soap settling, easy to recover any bio that ends up in the glyc when it's set solid.

BUT with my first two attempts I just kept going until meth flow was down to a slow drip, since then I just demeth to the calculated stiochiometric amount and stop and had no further problems.

I know doing it this way works well for me with my particular wvo, and I'm leaning towards variations in the method, or differing wvo feedstocks that may be giving rise to some of these other anomalies being reported.


We have covered the sterols before and I'm sure we decided that filtering and letting stand for a week or two was the best option to try and avoid problems, if it don't settle out in that time it aint gonna.

[Edited on 20-5-2009 by Chug]

Just done another 5/45 on the filtered Bio, fluffy stuff has now gone but shows a pinhead size drop out which I know is wvo.
I'm back to happy with it.
I'm setting up another batch today, this time I'll be using a stacked eductor, A hi-pressure feeding a lo-pressure.
I'm going to stop demething at 80% of stoichiometric, settle and drain down the glyc then demeth the bio as the standard method but still without a prewash.
Lets see how that comes out.

Jim
Got a drawing of the stacked eductor? I fancy giving it a go.

D ick

Been thinking about this....

I think that you, Chug use an eductor in your machine...? --I know that Jamesrl defo does!

Maybe my lack of one is causing some of my issues. The oil I have all from the same IBC so it doesn't vary. Its always de-watered overnight by venturi/condenser from 90 degrees down to 50 overnight. Same amount NaOH and MeOH,

Mk II will have eductor and I'll see if I can fit one to existing machine....(IF I ever get the bleedin' time!)

There has gotta be a reason for some guys success and others have issues....

I don't think Chug uses an eductor, I haven't sent him one yet.

OK ... second attempt at full batch demeth.

Having made two new ventures, remade pipe work and reverted to old sloping plumbers delight condenser, I managed to get 11" Hg from the second venturi. I'm still not convinced I have sufficient flow round the vapour circuit and sometimes get oil back tracking up the vapour line from the venturi however I thought I'd try a second batch, results as follows:

Two stage process draining glycerol between stages and returning it prior to demething.

First stage 1hr (sample taken)
Second stage 1hr 1/9 pass (sample taken) went into demeth mode.
Demeth for 2 1/2 hrs yielding circa 4 litres of methanol (so quicker than last attempt). Two tests on Methanol purity gave 96% after an hour and 96.5% at the end. Stopped demething and left to separate when flow to distillation pot slowed noticeably (not too scientific but it seemed a reasonable period). 1/9 test on bio still gave a pass.
Drained glycerol pumped to settling tank and bubbled over night circa 9 hrs. (sample taken after two days settling)

Shake e'm up tests on samples:



Left, after first stage processing. Middle, after second stage processing and before demething, 1/9 pass. (Chug ... not too sure what value this sample offers but you did request it be done). Right, after 2 1/2 hrs demething, 9 hrs bubbling and 2 days settling.




Jar from right, finished bio, turned on it's side and shot from underneath. Small amount of white scum evident. Is this likely to be DWS bearing in mind there's no drop out on the 1/9 test?

Still very impressed with full batch demething and will continue to use it. Even with a poor venturi, demething was much quicker than the first attempt but I'm still a little concerned about the white scum between the water and oil. Any one any thoughts?

Julian.

[Edited on 20-5-2009 by bio-rich-time-poor]

[Edited on 20-5-2009 by bio-rich-time-poor]

[Edited on 20-5-2009 by bio-rich-time-poor]

I too wonder about the usefulness of the shake 'em up on the pre-demeth and post demeth samples. Both will contain soap and is bound to give an emulsion if you shake it vigorously enough. A shake-em up with soap present is not a valid test of the presence or otherwise of mono or diglycerides (IMHO).

From the picture with the jar edge-on, it looks like you have a small amount of DWS and since the water is pretty clear, and therefore soap-free, this may be MG & DG.

Remember that a 3/27 with no fallout does not mean no MG of DG. A under-reacted sample will contain all three glycerides, the smallest amount will be tri's then di's and the largest amount will be mono's. When you see fallout in the 3/27, you're seeing completely unreacted oil,or triglycerides. MG and DG are partially soluble in methanol, leading to the haze you see in a marginal pass. It's a fair bet then, that the instant 3/27 clarity you get with a really good reaction, one that lets you add many times the normal ratio of bio to meth, contains very little MG and DG. Any sign of fallout will definitely contain MG and DG in direct proportion.

There is an issue with the shake-em up that needs standardising. I've seen people up-end the jar a few times and showing how clear it is. Personally, I shake the jar to hell and back. If it's pure, it will separate eventually with clear water and no emulsion layer. Perhaps we could try and come to a consensus regarding the execution of the test?

I think Chug's version of the whole batch demeth is brilliant and the issues people are seeing is due to pushing the methanol recovery too far. My experiments suggest that stopping the first stage demeth, as I call it, well short of the "stoichiometric", dropping the glyc and then finishing demething the bio, works very well. It adds slightly to the processes involved but well worth it in my view.

Cheers

Nick

Firstly Alistair,

I have no eductor yet, Jim's still teasing me...LOL!

I agree with Nick the shake em up test should be a well good shake, not just upended a few times, it will seperate quick enough if the fuel is good.

And even though soap in the "after 3/27 pass but pre demeth" sample will cloud the water it will settle out after a while and the mono and di glycs will settle at the interface between bio and water so I believe it's useful, but it's no good just doing one at the finish as you won't know if it was converted properly before demeth or just reversed because of it..

Julians samples show progressively less DWS at the interface as his reaction procedes towards completion.

Julian,
is it actually fallout, or is it sitting at the interface of bio/water?

if it's fallout then it could be soap or sterols
if it's sitting at the interface it's DWS.


[Edited on 21-5-2009 by Chug]

I finished a batch last night, I said is was going to stop whole batch bemath at 80% stoich. settle and drain down glyc then continue to demeth the Bio, as Nick (twenty4seven) is doing.

To my suprised the methanol volume increased above Stoich. and there was a distinct difference in methanol fumes when bubbling from quite a heavy atmosphere to almost undetectable.

I'll do a 50/50 shake up with de-ionized water now the soaps have settled, BTW I shake the guts out of my 50/50 tests, a good conversion starts to seperate in seconds and within 30mins I have water/oj. Take the lid off and 24hrs later it's all crystal clear.

Jim,

what do you mean when you say, you were surprised the methanol volume increased above Stoich?

you recovered more than the stoich?

You've confused me now, I'll have to go over my calcs and see what's what.

I noticed that a significant amount of methanol remains in the bio after the "first stage demeth" and the glyc dropped. I certainly wouldn't pump the bio straight into the settling tank after stopping short of total methanol recovery of the whole batch. Too much meth remains - you have to continue demething after you drop the glyc.

Cheers

Nick

Old fart makes mistake, agin.

Chug I marked my distilate vessel below stoich, forgot about that, continued to demeth after glyc drain down, bio only, and still ended it Just below stoichiometric 100ml or so.

I can remember stuff from 50 years ago like it was yesterday but I can't remeber what I did an hour ago, sad innit. Don't laugh, coz you'll all be the same in a few years, Ha ha ha.

I found that out last night Nick, nearly choked to death on the batch before that.

I'll be demthing after Glycerol drain down from now on.

I have been wondering if i were to drain glycerol then fill from the bottom with water to just below the element, no pumping.
Could i demeth this without problems ?
I am trying to keep the headspace down.

It seems like this two step demeth you are trying is taking a backwards step to me, it works fine for me just demething the whole batch down to stoich, but hey do whatever works best for you chaps eh?

I would NEVER consider adding water to the mix unless its for a prewash.

The head space dosen't make a lot of difference if your reactor is well insulated especially the top and upper parts.

My cylinder is welded steel so for safety i would like to keep the headspace down.
The no pumping suggestion was to prevent mixing up with the water. I assume from what has been said that circulating is necessary for demeth.
Whole batch demeth,- For wiring reasons i only have 2 KW available for heating so it could take a long time.
In any case i have a solar still for glycerol demething which costs nothing to run.
Does anyone use co2 inerting ?

I`ve seen Nick ( twenty4seven ) do a shake em up test, he`s right about shaking up to hell and back. lol 1 minute non stop shaking, bet his arms ached.

Well, Today I pumped the fuel out, It was still at 59 degrees, having de-methed overnight, Little in the way of foaming or other issues. Just a little cloudy. Lighter in colour, much more yellow than orange that the previous batch that was not pre-washed.--I used 7% vol/vol water

It settled for a few hours and my sample on the work-bench I took at pump-out midday, at 5pm today was still a little hazy, but there was a noticable lack of soaps settled--Very much less--at an estimate only around 10% of normal, and the fuel is getting clear...

(One thing I did notice, was the glyc, when I drained that, was rather 'frothy'--much soapier than on a non pre-washed, full-batch de-meth.....)

Will see what it looks like tomorrow, but the pre-wash after de-mething whole-batch, then settle drain glyc, and de-meth fuel left Looks to be a winner--For me anyway--So Far!...

I'll carry out DWS and 27/3 tests again tomorrow...

Removing the excess over the stoich shouldn't leave much if any in the bio, obviously if you stop before the excess is recovered you will have more in the bio...simples

No, but I've continued with whole batch and got slight reversal, thus the reason for me looking into stoichiometric amounts and adapting the amount I recover now to that, when bubbling the demethed bio there are no noticeable methanol fumes, I used to get more fumes from draining the glyc with methanol still present.

Yes it does look as though the amount of methanol you recover from the whole batch is crucial to avoiding a reverse reaction. Also, the temperature is important I think because (fortunately for us) the reverse reaction takes place at a much higher temperature. It will still reverse a bit at lower temperatures of course, but to a much lesser degree. That's another reason why I run my "first stage demeth" at no more than 70*C reactor temperature. Then, once the glyc has settled and removed, I feel more comfortable about racking up the temperature of the bio whilst continuing to demeth. At this point, the reactants which might give rise to a reverse are no longer present. It removes the last of the meth (down to trace amounts) and is nice and warm (85*C)when it goes into the settling tank where the bubbler finishes the job.

My concern remains though, that people may be putting hot bio into their settling tanks which still contains significant quantities of methanol (and then bubbling). I would hate to see anyone come to harm and an accident would do our cause no good at all.

I may be over-reacting (haha!) but surely it's better to be safe than sorry - at least until we have positive proof that demething the whole batch leaves only trace amounts of meth in the bio. I would urge people to try demething the whole batch to whatever level they deem appropriate, remove the glyc and the continue demething the bio to see how much meth actually remains in the bio alone. You may be surprised........


Nick

Nick and Jim,

when you stop demething before stoich amount is reached, drain glyc and then continue demething bio.

Do you recover any significant meth over and above what should be left down to the stoich amount?

Have you tried recovering anymore meth from the glyc after removing it before stoich reached?

I think tests on what meth is left in the glyc and the bio after demething down to stoich amount as per my method needs testing.

And testing what meth is left in the glyc and the bio after your stopping short of stoich method.

I understand the concerns about safety from fumes from bubbling residual methanol but there are folks who are doing all their demething by bubbling to air which is more worrying.

[Edited on 22-5-2009 by Chug]

I made my last batch of diesel on the 28 of April and although it was demthed using the whole batch demeth method it was a tad unsucessful. I only recovered 1.5lts of a possible 3.8lts. Because of this I decided to add a 5% prewash and then demthed my raw bio in the usual way.

However, I decided to bubble the raw, demethed bio and allow it to settle rather than water washing. I managed yto get a pass on the shake'm up test and filtered to 1micron. The fuel has been sitting inthe containers in my garage since the 2nd of May.

Now I've got to the point of this post...... I have white suspended soilds in my fuel after 20 days of standing. When I checked last week the fuel was still crystal clear. I've looked through this topic and see that some others are also having issues.

What's the best thing to do with the fuel now?

Nige

I have tried the whole batch demeth. Procedure was whole batch demeth to 80% of stoich then drop glyc then demth bio.

The 3/27 after the reaction was perfect. Now i've done another 3/27 from the bio sitting in the settling tank, and notice the cotton like balls forming, but not settling just floating around. That i think is what is later forming the white floating bits in the bio.
The whole process stressed me out. Because of the time it consumed doing the 2 demeths and i wont be doing it again i afraid to say.

This is what Ive found....

Ive done the full-batch de-meth three times now.

The first two, were as stated, Just do reaction, de-meth drop glyc, and continue de-meth till 'dry'

Tiny Balls formed after settling and second-batch fuel went cloudy some days after settling when stored in sealed container...

There was a LOT of soaps over the 'normal' way of only de-mething fuel...

I also had poor yield of the 110 litre oil batch, Reckon I got back only 85 litres...

I modded the whole-batch de-meth by adding a pre-wash stage After the main bulk of meth recovered, --around 9 litres in 2.5-3 hours, for 110 litre 24 litre MeOH batch
.
After the pre-wash, (7%),- glyc. drained and continued de-meth overnight, heat off (Ran out of time) Recovered only a few hundred mL of fluid.

The yield was also much better, around 100 litres finished fuel from 110 litres reacted.

Next day pumped out, settled overnight until today, fuel just a hint hazy but nice light colour, lighter than previous whole-batch reactions.

There was a marked reduction in soaps present after settling, in comparison to un-pre washed whole-batch and even a lot less than a 'normal' batch.

Soap reduction was quite marked, around 10% of the full-batch de-meth reactions, and say, only 50% of the 'normal' reactions....

The 27/3 test shows a clear pass, and the DWS test is also good.....

Next week, I'll run the same whole-batch with 7% pre-wash after the de-meth phase and see if it compares....

[Edited on 22-5-2009 by High Compression II]

I also got a bad yield 100 litres from 130.

Only got enough meth for 1 more batch then i'm onto wvo straight into the tank, i'll see how you guys go before i do it again.

I'm sorry to hear that some are having problems, I only do it as I've outlined by demething the whole batch down to the stoichiometric amount and had nothing but great results thus far.

From what I can remember there wer hardly any soaps in the bottom of the settling tank from my WBD. What there was was solid, probably about 7mm deep.

The thing that puzzles me is why it has taken the best part of 3 weeks to materialise!!!

I've now put all the fuel back in tank, cleaned out all my containers and filterered to 1micron again. Looks good again now.

Nige

This is SO strange....

It works brill for Chug and some others, while myself and yet more have some issues with it....

It MUST be summit to do with either feedstock or the processing equipment....

Cant be much else as we have all done the same sort of reactions in the same sort of ways....

IF my second test-reaction with pre-wash after bulk de-meth works out Then It'll be my method of choice from now on. Currently I'm using the same really good oil from the same IBC, and if all goes well, I'll put some cruddy, fatty stuff with and see what happens then.....

The WBD is a step forward, Thats for sure, Not sure of my recovered MeOH purity, but its gotta be pretty good, There wasn't any water in there when it was de-methed, Any that was there/made during the process would have ended up as soaps anyway, so recovered MeOH in Theory (theory being a wonderful thing,) should be near 100%

I wont use recovered MeOH on test-batch 2, just to keep variables to a minimum....

Have been wondering if the blobs we are seeing floating around in the bio could be polymers?
The longer the bio seems to be allowed to settle the more that appears. I have some bio that was produced on the 27-spr and filtered about the 3/4 May and left to settle again since then. It now seems to have the bottom 10% of the container full of these tiny white balls - which don't seem to dissolve in petrol. A shakeup test shows no sign of soap in the bio.
I know the batch of oil we used was in a tin that GM modified Soya - I assume that it had a fair proportion of Soya in the WVO we got - don't know if this is relevant or not.

Anyone any other idea?

I also know it is not necessarily directly related to the whole batch demething, as the batch I have was demethed after dropping the glyc.

Countrypaul,--Did you pre-wash the fuel that now has the strange white-balls sediment?

On the batches I had with balls, they were not pre-washed. I'm hoping my post de-meth pre-wash removes my balls problem.....It certainly reduced the soaps that settled and the fuel is good and clear at the moment.

We'll see if it stays that way!

HCII - no did not do a prewash on the reacted bio.

Might look at doing a prewash (?- or is it just a quick wash) after demething the bio.

The amount of soap in the bottom of the settling tank is reduced compared to standard method. The top is sometimes jellyish like egg white but orangey, over a thicker, maybe half inch solid layer with traces of glyc right at centre bottom. One or two batches, when I felt everything went really well just had solid soap, no jelly. (I love that when it all clicks together sweetly, it makes up for the times when I'm cursin myself)

The 'wet batch' I did had lots of weird slime and a thicker solid layer than others, and a reduced yield as expected.
In the 'last drained' cubee of settled glyc there is a larger visible soapier layer on top.

I've got one sample of bio from one of the first good batches back in March with no DWS that is sitting in an open top jar to see if it grows any of Graham's black mould, or does anything else weird, so far nothing, looks good as gold!

I DID have two samples, one from a batch with DWS but clumsy feckin twonk that I am, I knocked it over!

I hope to do another batch over the w/end too.

Done another full batch demeth today.

160L
22% meth
Processed as single stage with 2 eductors in less than 50 mins for 27/3 pass.

Demethed to 80 degrees, 12L in 3.5 hours (much better than last time but still less than 5l per hour) Total energy used @ 14 kw.

Bio clear - glyc settled in 20 mins, waited 10 more mins and got another cup full out.

Now bubbling bio in processor through the condenser to see how much meth remains.

About 37 L glyc separated out.

I have done water test before demeth and will do same before it goes into settling tank tomorrow and post results.

Will be looking for small balls or cotton wool in bio!

48 hour on Now crystal clear - no balls or cotton wool. Water test also crystal and no DWS.



D ick

[Edited on 25-5-09 by <b>****</b>jotec]

The cotton like stuff has now clunked together and turned into white balls confirming what i said earlier. There was no presence of water or air what so ever.

Feck it, you guys have put the jinx on me now,
I had a a slight yield reduction over my usual return and a little more glyc!

I did the reaction over the w/end using modded 2 stage and all went great as usual, moved onto demething and after an hour of it all going well I suddenley got a whiff of methanol, I looked closely and vapour was puffing out of the vent, it turns out the hose pipe to the condensor had been moved by kids playing in the pool and it had got a kink in it which almost stopped the water flow, so the condensor was too hot and the boiling meth was rushing along the pipe in bursts and getting to the end and puffing out then the the air was rushing back along the pipe.

other than that and the yield all else went great.

UPDATE:

checked the recoverd meth and it's 95-96% acording to how I read it, I must explain, currently I use a wine bottle as it's the only thing tall enough and with the hydrometer in it there is not much room in the neck and suface tension creates a diagonal surface across the markings!

[Edited on 26-5-2009 by Chug]

Today I tried my modified 'modified two stage with whole batch demeth' and have had outstanding results - my 27/3 is an instant clear pass, just yellow looking see through methanol. Not the faintest hint of haze let alone drop out.

It basically follows chugs method except after the first stage (using 80% of the methoxide) I stopped and let the glyc settle for an hour then drained it out. I then mixed in the second stage methoxide (remaining 20%) and let mix for 1 hr - test showed perfect 27/3.
I then put all of the still hot glyc from the first stage back in (pump happily sucked it in as it was hot and runny) and started demething. A bit like people do before a prewash in the two stage process except I didn't use any prewas water of course. Checked every hour or so and each time was the same perfect 27/3.
I have now demethed 22 litres of methanol from my original 66 (22% meth with 300 litres of oil). I reckon thats slighly short of stoichiometric but I'm happy to leave it there for this batch.
27/3 is the same again, not a sign of any haze, its just like putting yellow ink into water.

All told I reckon my modification puts about 1hrs extra time on the process and 10 minutes extra hands on with the processor but the result seems worth it. Now I am happy to start shortening mix times to see how things go.

Just thought I'd share my jubilation with everyone - if you are having issues with modified two stage it may be worth a go.
Jules

Chug I've had another go at the moded two stage and hole batch de-meth, much bettor results this time and this was a mix of bad oil, kebab fat and palm oil (a sacrificial batch), I now have 165L settling in my tank.
I will be doing it this way from now on.

Jules,

you are now doing the standard 2 stage if you are adding the 1st stage glyc back.

Paul/HCII,

keep us posted with your tiny balls testing.

I've got a sample from my early trials with this whole batch demeth in March which open to the air still clear and looking lovverly

Can any of you with these balls/cotton wool please take some pics and give us an update on your testing of it to find out exactly what it is?

I have approx 1/8 of a 15L cubee full of balls...

It was originally a half cubee full of Biodiesel and balls mixture, but has settled for a few weeks. I drew off the clear Biodiesel to within an inch or so of the balls...

I'll experiment next week on them. I have an idea they are soaps, but will try and confirm...

Since doing a Pre-Wash AFTER the 'Bulk' de-meth (Approx 9 litres from 110 litre batch, 20%), I have totally removed my balls and also have reduced the soaps that settle to a mere coating on the bottom of settling-tank

(In my test sample bottle for settling--a 3 litre PET Coke-bottle, the soaps that settle when the fuel is left totally clear after a few days, is just around 2mm thick, in the dimples that form the bottom of the bottle--I fill the sample 3L bottle completely full.....)

Pre-Wash AFTER De-Meth, Best of both worlds, Meth with good purity, and easy settlings with no balls!

if the wash is sorting it out then soap would seem to be the culprit, I just dunno why yourself and others get them without doing the wash and myself and others don't, but I only get about the same amount of soap you mention in the bottom of my test bottle too?

[Edited on 17-6-2009 by Chug]

Chug-

Yup, Its weird....

I did note, that during a full-batch de-meth Without post-de-meth pre-wash, I had quite a lot of soaps settling--More than a normal pre-wash, drop glyc, then de-meth reaction....

Gotta be soaps, but cannot explain why it works for some and not for others--maybe its the oil!--Who knows!

I found I got them even without the whole batch demeth - but this was without any prewash. I tried a water test on some of the bio that had them in and that showed no problem at all - maybe beause they had dropped out already.

They seem to dissolve more when the temperature increases - would that happen if they were soap?
Petrol doesn't seem to help dissolve them (initially thought it did).

Might be able to get a few photos on Saturday if I remember my camera.

Hmm, some interesting goings on whilst I've been away - Putting another batch on tonight hopefully, so will do Std 2 stage, and then WBD as I have been, but will add prewash after the WBD, are we still recommending 5-7%?? I'll then circ and drop the glyc, but will try and recover a bit more meth, although will keep it seperate as it will be less pure due to prewash water, than that which I get from the WBD...

Will update when done!

PS, not had any ball - but slow to drop soaps without prewash on last batch (WBD'd)

Mike

Possibly a silly question but, why not demeth, 5% prewash, then transfer the whole batch glyc and all to the settling tank, bubble overnight, let stand for a day or so and put through ecocrap or your usual cleanup process, I would think this would be better for those using NaOH as the glyc will "set" solid.

Any thoughts ?

those that are prewashing,

Does it keep the glyc from going solid even when it's fully demethed?

I wouldn't want my no prewash demethed glyc anywhere near my settling tank thank-you very much.

I agree with HC. I do a prewash after WBD and the glyc stays liquid.

Nige

Maybe I am missing something here, but why not do a prewash to stop the reaction dead before whole batch demething?

You could start off at 65C to get pure Meth recovered then switch collection containers and ramp up to 80-90C to get the rest out, even if it is tainted with water from the prewash. At least you'd know you've got as much Meth out as you're likely to ever manage with a condenser that way.

If I'm understanding rightly the only advantage of WBD before prewash would be to get purer recovered Methanol - but doesn't the biodiesel reaction produce some water anyway?

Since it seems that prewashing after WBD is the way to avoid cotton balls in the bio, then either way the glyc will have prewash water in?

Part of my trying this experiment originally was to reduce overall time, energy and messin abart with water and get purer recovered methanol to boot, as I believe some of the soap problems and longer time taken to reach 3/27 pass were related to my methanol having water in from when I did do the prewash.
Since I started doing WBD and leaving out the prewash I've been getting purer methanol back and things have been going great.

My standard method now is modified 2 stage using 25% methanol (using 25% means I just recover half of it, simples), then WBD, bubble, settle. never had any problems to worry about.

But if I'd experienced what others have with white fluffy balls them maybe I would think differently.

BUT, I will try going with trying single stage again once I get my eductor from Jim and get it fitted.

Interestin Paul'



So yours was not with a WBD but you still got the white fluffy cotton wool balls, HCII was leaning towards soap with his, but his was WBD.
So I thinking out loud, if the methanol helps keep the DWS of Mg and Dg in solution/suspension and demething allows them to 'fallout'.......

.....then I would have thought that I would have more of these white fluffy cotton wool balls than most as I'm quite happy with a little fallout in my 3/27's so obviously still unconverted oil and presumably Mg, Dg, and I don't prewash so they can't go out with the water.

Chug,

One other aspect that I forgot to mention is that the bio has been settled for a couple of days - it looks like all the soap has dropped out and it is clear but a few days after filtering into 25L carboys this cotton wool/balls appear. They tend to stick to the side of the carboy as well as settle to the bottom and it takes very little to stir them up - so the density may be very near the actual bio. It appears that when the bio gets colder more drop out, and when it warms there are less around.

I may have missed something but what are people doing with the rest of the reclaimed Methanol after stoich has been reached ?

I presume that because the purity is low it is just either wasted, in which case why bother to reclaim after stoich or is it being added as an "extra" to a normal batch again in which case surly the "extra" will dilute the new virgin Methanol to a level which may cause problems with processing.

Yours confused stumpy.

stumps, you've confused me now too,

once stoichiometric amount is reached I stop recovering , and with no prewash I'm getting 97 - 98% pure meth back.

I use 25% methanol as it makes the stoich amount exactly half to be recovered which I then just use as half of the next batch...simples

Chug,
What happens to the rest of the meth in the bio after stoich ? is it just bubbled off ?

Chug--

Ive been thinking and re-reading your previous posts concerning the 'Balls' issue....

i wonder if the fact you're using 25% meth and I've been using 20-22% for the reaction. --Wonder if this is the reason its been working well for you but not me/others...?

Dunno--Never gone past stioch, so not sure what the result Looks like...

What happened, how much Gravy do you have??

80ltr fats
16ltr meth
+3 ltr meth because 27/3 fail then pass
(7.6 ltr recoverable)
recovered about 11 ltr meth
about 10ltr glyc
15 ltr bio
rest gravy
been settling 2 week now very dark bio
would a titration help find out if it has reversed ?


[Edited on 16-7-2009 by tron]

[Edited on 16-7-2009 by tron]

Chug,
What happens to the rest of the meth in the bio after stoich ? is it just bubbled off ?

HCII
yeah that is my understanding too, the reaction cannot reverse once the glyc is removed, the methanol is locked to the fatty acid.
And I've only been using 25% methanol for the last few batches, before that it was 22% and no cotton wool balls

Stumpy
I bubble overnight after reaching stoich and draining glyc off but since I've been doing WBD I hardly notice any methanol smell from bubbling.

Tron

I think you recovered too much methanol if you took out 11 litres, you put 19 litres in which is almost 25% so you should have got almost half of it back around 9.5 litres, so your gravy is probably lots of mono and diglycerides.

[Edited on 16-7-2009 by Chug]

okey dokey thanks for the updates HCII & Chug.

I must be having a blonde day today.

It's possible, if the majority of the oil is rapeseed, which has a stoich of about 11.8 or summit, lower than 12.5% average
that there will be some residual methanol in the bio

so I like bubbling overnight just to be sure, and this is confirmed by test samples on the bio taken before bubbling and left to settle which take longer for the soap to drop.

If palm is used then the stoich will be higher...like about 14% or 15% so less meth to recover.

yeah try a test sample with 1g NaOH and 50ml methanol per litre of gravy.

think i've got it report later ,hopefully

well fought the gravy and won i think
all i did was return the methanol that i recoverd and mixed for 1 hour @ 50deg but it looks VERY soapy we shall see tomorrowbubbling overnight.
i mayhave tobuy some diesel

Not wanting to cause an argument Chug , but I've always assumed that palm oil would need less methanol?
Longer chains meaning higher molecular weight therefore less molecules per gram? Though I don't know how it's density compares...

I've always ended up using more methanol and getting lower yields with palm heavy batches, but I think that's just down to driver error and a poorly mixing, badly insulated reactor.

I did sit down and work out the chemistry for 4 or so different weight oils, but that was ages ago, on the back of an envelope...

Pete

I have now reached the point where I'll be doing no more whole batch de-mething. There are too many things going wrong. I've spent 3yrs making bio always using the prewash and then water washing the bio with no problems. Since adopting this method it has frustrated me at every turn. For a method that was supposed to save me time and money (by recovering the meth) it has done the complete reverse.

I've made a batch this afternoon which went OKish but had a 0.05ml dropout using a 5/45 test. I then went to WBD and recovered 2lts in one hour. BTW I had 10lts of methanol in the batch. I decided to stop there, well short of stoich, and did a 7% prewash. I've just turned off the plant and tried to take a sample, I like to see the seperation going on, but just like Tron I have a reactor full of a solution that looks like gravy. I've not had this before but I have always done a prewash on the previous 4 WBD batches.

It appears as though putting the methanol back in does allow a degree of seperation and I'll let you know in due course how much of my valuble fuel has been lost.

Yours....P****D OFF OF LEICESTER.

Nige

OK...here's where I'm at. I re-introduced the meth I recovered and let the whole lot mix for a while. I took a 1lt sample and watched what happened. The results are, the methanol caused the GRAVY to seperate back into what we would normally expect to see ie two distinct layers when allowed to stand.

The figures are approximate but it appears as though I have the 27% by-product that I would normally expect. This derives from the 20% methanol and the 7% prewash.

The whole batch is now standing and I'll drain off the glyc/prewash and demeth the raw bio before pumping ito the settling tank.

Nige

Good luck,hope you dont lose any
K

update
the lot has set in settle tank ,(good job i put into a spare settle tank i have (old dustbin),can remove some bio but it is very little)filtering with sieve,don't like to waste any

sorry to hear you are having problems Nige and Tron,
All I can suggest is try it exactly how I do it and see if it's any better, or go back to what did work for you.

I've only had three minor niggles, on the first two ever I recovered past stoich and got a little DWS, and one other batch was processed with water in making lots of soap and reduced yield and since adopting WBD I don't prewash.

The only thing I do differently now is, for the last few batches, I've used 25% methanol as it makes working to the 12.5% stoich means exactly half to recover.

sorry chug but i can't afford to lose any more bio, i'm tight fisted you know, i don't want to pay oil companys anymore,had to buy diesel today it realy hurt the wallet, going back to gl's way( prewash), may try later when i build up a stock of bio.

Tron,

so you made a mistake and fecked up one batch,
I'm not sure why you're saying sorry to me, we all do something wrong from time to time, treat it as a learning curve, and if this one mistake has put you off WBD then that is your choice, I'm not saying everyone has to do it this way, it works great for me and is my chosen method, but hey do what you are happy with.

After a miserable result with my first trial of the eductor see eductor thread
http://www.vegetableoildiesel.co.uk/forum/viewthread.php?tid=12385&page=1...

I moved onto demthing the whole batch, previously on friday I fitted a brand new grundfos C/H pump to the beer cooler and was keen to try the beer cooler out after saturdays bio brewing.

BUT I had a feck up when I spilled water onto the pump and it blew up! so I dug a spare C/H pump out, I had already swapped the fittings from this pump to the grundfos on friday and now had to swap them back!

All sorted, but for all of 10 mins! until I dropped a spanner and broke the speed contol switch off the top of the pump, I tried to bridge the contacts with some brass strips and wire and solder but after 30 - 40 mins I gave up and turned to a pond pump instead.

This proved to be not up to the job and although the water going into the bottom of the condensor was only 1-2°C it barely had enough flow with the pond pump and was coming out the top of the condensor really hot, after 2 hrs trying to demeth like this I only had recovered about 3 litres, so I decided to switch back to my old hosepipe method, this helped a bit but was still not up to my usual 5LPH average, then I realised another problem my oil temp was lower than normal.
I had been given a temp probe by Martin (jim speedy) at my BBB and this was reading approx 10 degrees too high at the still head, once I got the old temp probe back on and increased the temp to a real 65°C things started flowing nicely again, but the result was it took me from 1-45pm until 7-45pm to recover 15 litres, usual time is 3.5 hrs to recover 17.5 litres.

If I can find/scrounge/pilfer another C/H pump before I do my next brew I'll try the beer cooler again.

Sorry to hear of your troubles you guys....

Chug--

Told you before, Pumps dont Need a cuppa before starting up!

How did the chiller work out?--Or is it a bit early to say...?

One thing Ive noticed, as I did a batch on Friday, is the colour....

Usually doing a 'normal pre-washed and settle drain glyc', (Not WBD) the fuel is normally a 'lager' colour, maybe a little darker....

WBD, with 25% meth and 12 litres recovered from 100 litre batch, the fuel looks like Newky Brown!-(Without the head......)
-Very dark in colour, --Its settled well after cooling in settling-drum and is 'sparkling-clear' today, But VERY Dark in colour....

Anyone else noticed this?

I think the beer cooler will be ok if the pump used in conjunction with it can keep up, although condensor doesn't needt much more than a dribble from the tap the pond pump flowing less and down to head height more than anything else methinks.

I haven't really noticed any real colour difference, but Nick reported lighter BD after WBD here
http://www.vegetableoildiesel.co.uk/forum

[Edited on 27-7-2009 by Chug]

How is this method working out over all? I like to get my reactor clear as quickly as possible to start a new batch so I've not tried it.

Basically my method goes React, settle, separate glyc, demeth bio (different vessel), settle till needed, dry wash.
After enough reactions the glyc gets demethed too and settled.

I might be missing the point but here are the advantages I see:
Methanol recovered quicker (safer, higher % recovered etc).
Glyc removed at one point, saving passing through as many filters. (could save on wear and tear maybe)
Energy savings (small but they add up)

Disadvantages:
Chance of back reaction (maybe lower quality fuel)
Heating up whole reaction (I'd need a larger Demeth vessel)
OR
More time between batches (if reactor is used)

Looking at it from a pro vs con angle I don't see much in it either way. Are there other reasons?

WBD advantages-

Recovered meth instantly available for next batch

Recovered meth is of usable quality.

Less time wasted messing round recovering meth from glyc, and energy not wasted re-heating stone-cold glyc..

Less apparent soaps settled out after pre-washing post de-meth phase in WBD.

Disadvantages-

In my case, adds maybe 1-2 hours to a days fuel-making, as the de-mething phase adds time--Could be minimised with equipment mods maybe.......

In some instances, a post settling issue where 'balls' are formed some days later--Seems to be cured by the pre-wash, post de-meth...

Fuel very dark in colour--whether this is a disadvantage or not--Not sure, but it indicates something is staying IN the fuel thats removed by normal processing...

HCII, whats the viscosity of this dark bio? Would a variation on a 2 stage method/WBD improve results?

Bio that we have used from loads of suppliers does vary in colour with Golden Fuels being the lightest we have ever seen (I think they 2 stage but not for much longer I fear)

The darkest stuff came out of a plant in Middlwich which smelt like sick.

We have also noticed our bio go dark red/brown when we dose with Baynox plus. I will be asking Lanxess's leading chemist why this is when I go to Stonlegh in October.

Uncle Slabs

Tim,
Give it a try
I'm completely sold on WBD, it's my standard method now, I used to store glyc from several batches like you and then demeth that on it's own, so I'm saving that time and energy now with WBD, and fuel quality is still as good as ever and recovered methanol is used as half of the next batch of methoxide.

One guy on infopop did a 250 gallon batch WBD over the w/end and had great results and his soap ppm count was half his normal ppm count on the same wvo and he saved 10 -12 hours over his normal timescale, and even though he recovered slightly over stoich and got some DWS he was well pleased overall.


HCII

that will be a good experiment keep us posted, and pics, if different colours or viscosity, would be good?

Chug

Any chance of a link to the infopop topic please.

http://biodiesel.infopop.cc/eve/forums/a/tpc/f/719605551/m/989100721/p/1
try this

Chug, I have an old c/h pump in the shed, it came out of my old combi boiler, it's your's if you want it, when you doing your next batch as I may be able to bring it over before then and pick up those wheels at the same time.

Ta Very much

Sorry Mark I've only just seen your post,

yes, you can swap it for a wheel eh?

I've had one or two people email me for my latest version of whole batch demeth (WBD)
so here goes!

FIRST SOME NOTES
Before starting to recover methanol from the whole batch you need to work out how much you can safely recover before the possibility of reversing the reaction.

The biodiesel reaction will need an average of 12.5% methanol (this varies with different types of wvo feedstock from about 11% -16%) But we take 12.5% as our average.
This is referred to as the stoichiometric amount, or stoich amount for short.

If you use 22% methanol there will be approx 9.5% excess methanol over the 12.5% stoich amount.
If you use 20% methanol there will be approx 7.5% excess methanol over the 12.5% stoich amount, you get the idea.

BUT, we stop recovery 500ml or so short of the total excess over the stoich amount that is available just to be on the safe side.
So with 100L wvo and 22% methanol (22 litres) there is 9.5 Litres excess methanol available for recovery before reversal can occur, but we only take 9 litres then bubble off any residual methanol once the glyc has been drained, or just continue demething the bio on it's own in your processor.
If you still don't understand there is a guide here
http://www.biofuel-uk.net/recoverable%20methanol.doc

Or even easier, as it's recoverable why not just use 25% methanol to start with then it's just under half of what you started with available to be recovered.


THE METHOD
Do your reaction by your preferred method, until either, reaching a 3/27 pass, or until your usual end of reaction stage, BUT do not drain the glycerol, we recover methanol from the whole batch biodiesel and glycerine together.

Start demething and try to keep the vapour temp, or head space, or still head, between 65°C and 70°C (for better methanol purity) and keep recovering until you have recovered most of the excess methanol, stop and allow glyc to settle for up to an hour (be aware that NaOH based glyc will set hard quickly and cannot be left too long) drain the glyc and move bio to your settling tank, bubble with air for a few hours or overnight, allow 12-24 hrs for soap to dropout and then filter your bio using your preferred method and use or store.

OR
After draining the glyc off continue demething just the bio and then settle and then filter your bio using your preferred method and use or store.

Prewash.....
If you previously prewashed as part of your method you should find it's no longer necessary, but if you would still like to prewash then do it after demething the excess methanol, but before settling and draining off the glyc, after prewashing settle and drain off glyc and water.




[Edited on 2-8-2009 by Chug]

Thanks for that Chug...Good to have it clarified at the end of the thread....Maybe worth having it as a sticky, or start another thread with just that post and lock it...keep this thread for reference and ideas as is, but have an easier to find instruction thread...

Good read this thread has been and successful for me so far with my best results so far....

I process in a little stainless pressure vessel at 85C. when the reactions done I open the vent valve which feeds through a heat exchanger and methanol liquid is collected. The pump and heater are still on. it hisses like mad and u can hear the meth bumping inside

when the methanol flow slows to a drop evry 10 secs or so i then settle.

good results like this with no detectable back reaction occuring.

I did notice KOH whole batch demeth is alot faster than NaOH demeth. Anyone else noticed this?

possibly due to the higher charge density on the sodium ion clinging onto the hydroxyl lone pairs of the methanol more than K+. Seen this effect coming into play before with Al 3+ ions in solutions

Thanks Chug for showing the instructions at the end, I've being trying to set aside the hours needed to go through this thread since your bash, havent had the time until today

Much appreciated

coXen

Thanks Chug, I may try this. One question, Re:
'drain the glyc and move bio to your settling tank, bubble with air for a few hours or overnight, allow 12-24 hrs for soap to dropout and then filter your bio and use or store'.
Why not just demeth the remaining meth in the processor in the usual manner?
After drain the glyc that is.


[Edited on 31-7-2009 by Bioroy]

[Edited on 1-8-2009 by Bioroy]

bioroy

yes, once the glyc has been drained off you could continue demething the bio in the processor.

Ok then how about taking it one stage further;

After demething bio, as I have a good mister built into my GL processor,doing a mist wash using a max of 20 or 30 ltrs water. Drain of water & dry in processor. More of a rinse than a wash, but if soaps reduced by this method any way do you think it will be ready to use or at least even cleaner! Do you see any risk?
Normally I don't like washing! Something to do with my second childhood.

[Edited on 1-8-2009 by Bioroy]

I recover the excess almost right down to the stoich amount so I'm pretty sure what methanol remains would be similar to HCII stopping when just a slow drip, and the bubbling is just to be sure any residual methanol is removed so it's fully demethed.

I really cannot see any reason why you would want to 'rinse' your bio, if it's fully demethed then the soap just drops out, not having to use water is why this method evolved.

I think some of the problems folks are getting with stuff settling out is beause they still have methanol in their bio and when it evaporates whatever was in solution can then drop out, since I've been bubbling after demething I've had nothing settling out days/weeks later like I used to.

Ok, I also like the idea of keeping soap settled in the 210ltre tank to a absolute minimum.
I may have some other options. I use KHO so I could leave the glyc to settle for several days & perhaps it will take the quickly settling soap with it. Demethed KHO Glyc does not set but does go like treacle, I can warm it up again quite safely as the processor is heated from my gas central heating system, I have a indirect cylinder. I have a ceramic air-stone plumbed into the bottom so I can bubble it & use the venturi to ensure any methe is condensed out after, as you say. Then to leave again to settle out any remaining soap before pumping to the 210 storage/ settling tank.

For ever looking for the perfect system!!!

I know it's only a little meth bubbling to atmosphere but I keep meaning to try putting my bubble ring in my processor so that no meth vapour escapes to atmosphere.

I have a bubbling ring in the processor and capture the 'bubble' from the final demething.
Depending on the process used it can be as much as half a L but is often much less.
I don't run the cooling water for the final bubbling so some might still escape to atmosphere.

Like Chug I also have not had any problems with settling out on the WBD method.

(BTW just got a beer cooler so hope that I can reduce the demeth time even more next time)

D ick

Question for those that stop demething well short of stoich.

When you stop demething well before stoich amount is reached, drain glyc and then continue demething just the bio.

Do you recover any significant meth over and above what should be left down to the stoich amount?

Has anyone tried demething the glyc further after draining?

I'm trying to determine if the excess methanol available to be recovered down to the stoich amount has more affinity for the glyc or bio or is equally distibuted in both?

Just had some interesting feedback from some of the guys across the pond who are using WBD,

PHlip test results from Jon were very good.
http://www.biodieselpictures.com/viewtopic.php?p=1453#1453


And fabricator is doing 250 gallon batches and getting encouraging results on soap PPM tests, 900 PPM tested straight after WBD and reduced to 31.5ppm after 3hrs through shavings.

Interesting -wish we could get some of the Phlips.

I shall continue with the one stage process and WBD as it seems to work very well for me and saves time and electric.
D ick

I'm endlessly fascinated by this thread, I think when I get processor #2 built I'll try WBD using 25% Meth, but like Alistair do a 7% prewash before dropping the glyc.

Without the prewash would there still be some NaOH floating around in the bio or does that drop with the glyc too?

[Edited on 27-10-2009 by tttonyyy]

The NaOH will effectively drop with the Glycerine. With the WBD some soap may be left in the, along with a little methanol and glycerine. When you bubble teh bio to get the last of the methanol out, the soaps will drop out of solution quite quickly and ant remaining glycerol will settle out too.

Tony,
The last WBD I did had a neutral pH so I assume no NaOH was left after the reaction and demeth. Have not tested any previous batches for some time.

D ick

Oh that's interesting. I figured prewash would at least clear the bio of any impurities that were water soluble.

I'm sure I read somewhere on this thread that a prewash after WBD made their bio a different colour?

There's no need to do a prewash, everything drops out after bubbling. I'm now using my cyclone to spin out any remaining glycerol and soaps.

Tony,

the NaOH drops out with the glyc the only thing left will be residual methanol and soap/trace glyc but if you have wvo with High T then it might be helpful to do a prewash after WBD and before draining glyc to help with the extra soap.

Now that quite a few have tried the WBD, or are doing it regularly has anyone got any feedback on DWS/back reaction, cotton wool balls, different colour bio to usual, delayed fallout, that are reported in this thread, or any observations or variations to the method that you wish to share?

I started a WBD but ran out of time so only recovered 3.5 of the 11l I intended (11.5l to stoc). Those 3.5l were very pure however - and I was impressed with the rate of flow too - video of it here:

http://www.youtube.com/watch?v=KZzwrvkuuKE

The only thing I'm not so happy about with WBD is that there is no natural "break point" where you can leave it for a day. So normally if I added the prewash water I know I'd be good to leave it until tomorrow, but with WBD there is the risk of the glyc setting.

As expected with only recovering a 1/3 of the available meth there were no signs of reverse reaction, perfect 27/3 test. The bio is a lot darker without prewash though. Eyes out for any fluffy balls forming.

4 days on and I have what appears to be tiny little white balls forming on the surface of the bio. Pumping from below the surface makes them stick to the sides of the drum.

Bio passes 27/3 even with meth/bio at 10C.

Because I stopped early I didn't go anywhere near stoic, so can't be reverse reaction - unless it's caused by mono/di-glycerides from incomplete reaction that didn't show in the 27/3?

[Edited on 24-11-2009 by tttonyyy]

tttonyyy - if you take a sample of these white balls with a little bio and warm it up do the dissolve? Several of us have had this and there is a strong suspiscion that they are high melting point esters that are dropping out of solution in the colder weather. Not sure why they don't appear when using the normal method for production, but maybe it's something to do with the prewash.

I've been going down the WBD route for a few months now and only recently noticed the wee white balls on the side of my tank. Maybe it is temperature related.

I've now made 2x100l batches going back to the 6% pre-wash to see whether that will make a difference. They have been bubbled overnight and will be settled for a week.

Yes - they're just like what I've got though I seem to have much more than you.

Some of my source oil was verging on creamy so hopefully just high melt esters.

I guess I could use a hot air gun to gently warm the ones in my barrel and see if they melt.

tollie, your 100l batches, did you do the Meth recovery to just below stoic and then do the prewash?

I must admit I'm concerned that the bio is so much darker with WBD - there must be something left in it that the water pre-wash removes. My bio is that dark that it was hard to distinguish the colour change when draining the glyc - it's that the liquid went suddenly runny that indicated it was bio. And this is oil that only titrates at 1.3, so not heavily used. The source oil was quite dark - mostly from an Nepalese restaurant. Maybe it's something they cook with?

[Edited on 24-11-2009 by tttonyyy]

I'm seeing the same stuff on the walls of my settling tank - but much worse... I scraped some off the tank and put it in a jar next to the wood-burner. It didn't liquefy fully and the temp was well over 20*C..... are we looking at HMP esters or sterol glucosides?.... I'm leaning towards the latter. More worryingly, the sample containing 10% RUG I left in the fridge showed significant fallout after several days - light fluffy stuff. The feedstock was nice liquid stuff so this is baffling.

my experiance with WBD is pretty much nothing to report bio same colour settles out over night but i just filter 20ltrs at a time so it just sits in the settling tank until needed.for the first 12 hours ive been putting my aquarium heater in because we had a cold snap up here.but ive not noticed any drop out in my samples i keep on my workbench.note i only use the aquarium heater when the temp drops i dont use it in the summer.also the last batch was made from the dregs and was pretty horrid stuff as i cleaned out my storage drum <not a nice job> so all good here for now.Oh and i still did a 5% prewash.

Maybe it is the prewash, having NaOH/water that affects the SGs. There's a bit more about it on this thread:

http://www.vegetableoildiesel.co.uk/forum/viewthread.php?tid=13572

I've been experiencing similar problems with WBD as discussed on this thread http://www.vegetableoildiesel.co.uk/forum/viewthread.php?tid=14787&page=1 with photos on these pages:
http://www.vegetableoildiesel.co.uk/forum/viewthread.php?tid=14787&page=3
and
http://www.vegetableoildiesel.co.uk/forum/viewthread.php?tid=14787&page=4 (filtered precipitate photo near the bottom)

I don't seem to get balls forming in the settling tank but then the shed is heavily insulated with a radiator running off the central heating system (I know, Southern softy but it used to be my workshop/retreat) and rarely drops below 10°C at the moment. My problem manifested itself when the fuel was put in the car resulting in a blocked filter. Samples outside develop white wispy clouds that take a very long time to settle if at all.

Never had the problem with the 5% prewash method so I tried combining WBD and 5% prewash methods and so far (in a sample outside for about a week ) the problem has not reoccurred. The one significant difference between batches was that the WBD + 5% PW has Coldflow added, so not entirely conclusive. I think I read somewhere that a major component of winter additives was Toluene. Looking at this thread http://www.vegetableoildiesel.co.uk/forum/viewthread.php?tid=13572 is it possible the cold flow has had an effect?

I've got around 100 litres of WBD which suffers from this precipitate so I'll try recycling some this as a 50/50 batch with oil as a WBD + 5% PW and see if that prevents the precipitate forming.

Just a hint of warmth from a lighter's flame near the side of the tank and the little white balls melt, so probably nothing worse than high melt esters in this batch.

[Edited on 25-11-2009 by tttonyyy]

The worst of the HMPE's is the methyl ester of stearic acid which has a melting point of around 39°C, all the other HMPE's will melt at lower temps than that. But SG's need something mad like 240 - 250°C before they will melt.

Running another WBD now. Used 7l of recovered Meth from last time - 3.5l from WBD and 3.5l recovered from the bio (no prewash) after dropping the glyc - both very pure. 27/3 pass no problem on this batch!

Planning on getting 10l back from this one and then prewashing before dropping the glyc this time.

So far 4l in 1h 40m

Edit: Got back 9l before giving up for the evening, added 5% prewash. Left overnight (thank you pre-wash!), drained glyc this morning and got about 85% yield, not as good as last WBD batch but then it titrated a lot higher.

[Edited on 29-11-2009 by tttonyyy]

A few days later and I've got just a few balls floating on the surface of this one too - exactly the same as last time - but a lot less of them.

Don't know whether to attribute reduced numbers to the 5% prewash or the extra demething.

floaters eh,

have you investigated further are they soap or HMPE?

EDIT:

I had an email from a professor whose field is fatty acids and he says "the melting points of the monocaylglycerols of
palmitic and stearic acids are a little above 70 C" and recommends a book 'The Lipid Handbook, 3rd Edition' it's voluminous and expensive but apparently, the second half of it contains information on properties of individual fatty compounds as a dictionary-type section.

I'm hoping to get a copy of The Lipid handbook from rapidshare if my registration is approved.

[Edited on 4-12-2009 by Chug]

Chug ...

This book seems to be on Google books <a href="
[url=http://books.google.co.uk/books?id=INZa6WmqDA8C&dq='The+Lipid+Handbook&printsec=frontcover&source=bl&ots=Sr6BadbCt6&sig=DzcH0 npN_A-cNQ9leZaMLhAzsT0&hl=en&ei=t0oZS73EGIm04Qa8ieXvAg&sa=X&oi=book_result&ct=result&resnum=11&ved=0CDgQ6AEwCg#v=onepage&a mp;q=&f=false]http://books.google.co.uk/books?id=INZa6WmqDA8C&dq='The+Lipid+Handbook&am...[/url]
" target="_blank"><b>click</b></a>

Haven't looked through it as the chance of understanding it is slim!

Hmm ... link won't work. URL is as follows:

[url=http://books.google.co.uk/books?id=INZa6WmqDA8C&dq='The+Lipid+Handbook&printsec=frontcover&source=bl&ots=Sr6BadbCt6&sig=DzcH0 npN_A-cNQ9leZaMLhAzsT0&hl=en&ei=t0oZS73EGIm04Qa8ieXvAg&sa=X&oi=book_result&ct=result&resnum=11&ved=0CDgQ6AEwCg#v=onepage&a mp;q=&f=false]http://books.google.co.uk/books?id=INZa6WmqDA8C&dq='The+Lipid+Handbook&am...[/url]


No, that doesn't work either the forum seem to be adding bits to the URL ??

You need to delete the " [url= " at the beginning and the " ]http://books.google.co.uk/books?id=INZa6WmqDA8C&dq='The+Lipid+Handbook&prints...[/url]
" at the end. Or perhaps just search Google books!

[Edited on 4-12-2009 by bio-rich-time-poor]

[Edited on 4-12-2009 by bio-rich-time-poor]

[Edited on 4-12-2009 by bio-rich-time-poor]

Thanks Julian

I've literally just managed to get a full copy downloaded from rapid share.

If anyone wants a copy email or U2U me and I'll send it.

Will it make sense to anyone without a PhD in chemistry?

[Edited on 4-12-2009 by bio-rich-time-poor]

I had a quick look to make sure it was all there and some of it is quite complex if you don't have a basic working knowledge of what fatty acids are, but there are some nice charts to look at if you cant understand the tech text bits.

I have some floaters in my settling tank as well as on the sides, I scraped of a sample to test and just the warmth of my hand was enought to turn it back into bio.
So it appears to be HMPE. This is only the second time it's happened and it seems to coinside with a cold snap.

if it melts at 50 then it's not SG's and according to my friendly bio prof palmitic and stearic acids can require up to 70 before they melt.

Well curses, my last WBD has loads of floating balls (and suspended ones) despite the 5% pre-wash. Bio is a perfect 27/3 pass and I stopped clear of 12.5% stoic.

I've scraped and scooped a good concentration of them up into a jar with bio.

Some of them are soft and some of them are like hard grit between fingers.

I heated my sample in the microwave (I'd guess 40C-50C) and most melted in, but some didn't.

However with the heat those remaining ones settled to the bottom. This could be because they are little soap blobs and I bubbled for 20 hours, after which the bio was cold and thick enough to hold them in suspension.

I'm going to take another sample and add 5% petrol to see if thinning it makes them drop. Otherwise I'm going to need to either re-heat and settle, or filter my batch through jay clothes to make it usable.

I can only conclude that 5% pre-wash doesn't necessarily help with reducing ball formation.

I'm going to stop WBD and see how normal production is turning out with my source oil in this weather, before blaming WBD for my woes...

[Edited on 10-12-2009 by tttonyyy]

OK, I admit it, I'm addicted to WBD now.

There seems to be a pattern between source oil with whites and then fluff/balls in the resulting bio, which I can only attribute to HMPEs. Not a problem if filtered before use.

I'm thinking of dropping my prewash stage as it doesn't seem to make any difference to fluff/balls, so the current batch won't have water involved at all - fingers crossed!

Last but one batch WBD had a suspended fallout in the settling tank for the first time.
I filtered through cloth and was left with a soft paste. I have scooped some into a jar and it is sitting on the shelf to see what happens to it.
It does turn liquid when heated but returns to paste when cooled.
I intend to experiment further sometime.
The last batch is settling and I will be interested to see if there is a similar fallout.
Bio is fine and the system was exactly the same as previously. The only difference was the temp the oil experienced before processing (V cold) and the air temp while processing and settling. The caustic is also going off, as I find it tends to after about 12 months.
D ick

D ick, I get them all the time, some batches fine but some batches loaded with them, it's just high melt point esters as far as I can tell and returns to bio at room temp.

It seems to help it drop out by reheating the batch and letting it settle again, don't know why - but I've had no problems whatsoever using it as fuel after cold filtering.

My dregs barrel was particularly rich in them, I guess from all the bottoms of batches. I've filtered that and used it as fuel (the j cloth around the filter element seems to catch it before it hits the 5 micron element itself).

Alistair mentioned somewhere on here, that he thinks that WBD gives greater yield because the HMPEs end up in the fuel rather than the glycerol. Won't be an issue come summer!

[Edited on 29-1-2010 by tttonyyy]

For information this is a picture of the residue from the last but 1 batch.


If anyone wants any tests done let me know and I will do them.
Current temperature is 2C but it was the same at 8C 2 days ago.
D ick

<b>****</b>jotec ...


I've had the same problem see this thread ... http://www.vegetableoildiesel.co.uk/forum/viewthread.php?tid=15458

Try taking it indoors D ick. I also tried adding petrol to mine when it was liquid but it didn't stop it reverting to the way it was.

I've collected a few litres of smeggy stuff from the bottom of the last few batches, some of it turned back to bio in the warmer temps but in the last few days has gone smeggy again, I'm just demething a batch now, but my temp sensor which is stuck in with mastic has come loose and I've got a few whisps of meth vapour leaking out, but despite this so far it's the best result I've had for demething, 12 litres in 1 hour 50 mins.

I forgot to thank Chug at the BBB for his work on this, as it's really changed the way I make bio. So thanks Chug

I've also found that ball formation is easily avoided just by covering the bio settling drum for a few days after bubbling. Might be something to do with dust getting in and forming nucleation sites. Now I tend to find a creamy layer at the bottom over the soap (if at all).

Yes Thanks Chug.
My settling tank has always been covered and I have never had the ball problem so you could be right Tony.

The residue shown in the pics above is still the same consistency as it was so ambient temp does not affect it.

D ick