My oil has a titration of zero after an acid wash and base "but" i'm getting no seperation,whats up?

more details on what you did would help?

-dkenny

DK-we have had many sucessful batches of biodiesel in the less than 9 titration,"BUT" dealing with this higher titration levels have been nothing but failiers,We are trying to follow your recipe and keep getting to a "no seperation" point. It seems the oil just won't break. Most of the time we get a slimmy film on the top, one time we got a mass of foam that spued out of the top,basicly the oil titrates out @ zero and looks like black glycern. If we add more methoxide it turns to glop,adding methonol does nothing,adding meth and acid drops out the lye and gives something of a bad seperation, stoping the reaction with water seperates but not a pretty site,cutting with a low titrate oil does not help.right now we have 95 gallons with 500ml of acid, 19 gallons of meth and 1600 grams of sodium sitting in our reaction tank after the two stage process with a titration of zero, slime on top,no jelly at the bottom,oil is dark and not seperated

1. what was the initial titration?
2. was the oil dry?
3. how much oil, mehtanol, acid used for the acid stage.
4. what processing temp?
5. for how long did you process the acid stage?
6. what was the ending titration of the acid stage?
7. how methanol did you use in the base stage?
8. how much caustic? what type? base amount?
9. processing temp of the base stage?
10. for how long?
11. what type of reactor are you using? is it designed to keep methanol in?
12. did it pass the 27/3 test before you added water for the 5% prewash?

-dkenny

DK
1.original titration is 10
2.oil is dry we boiled at 250 for 8 hours
3.448ml acid----11.5gal meth
4.processing temp 150 to 180
5.mixed acid stage 4 hours
6.ending titration of 7
7.meth on base stage 8gal
8.3700g sodium
9.temp 150
10.mix 3 hours
11. retitrate at 1(no seperation)
12.drain 20 gal
13.mix 8gal meth 1615 sodium
14.mix 4 hours (no seperation)
15. settle overnight (no seperation slime on top and jelly on bottom
16.reheat to 150
tests-- meth and acid drop caustic, oil on top dark with glyceren

you do know the sometimes the BD from the acid/base processing is very dark. just like glycerin. thereby making very hard to tell the difference?

also how oil do you start with?

you might consider running the acid stage longer unless the titration stopped dropping.

10 NaOH is the same as 14 KOH and this is the starting point in which one should settle and drain between stages.

7 NaOH is still high for base processing

try taking 1 liter and 50 ml methanol and 1g NaOH

it does sound like you didn't use enough NaOH.

is you processor setup to prevent the loss of methanol?

-dkenny

to DK
I've pretty much had with this batch,been 3 days of screwing around trying to get a seperation from the glyceren molecule into some methel esters.For some reason the lye seems to be suspended and not doing anything?So i've acid washed the 100 gal with 4000ml sulfuric acid,Results- no more slimmy skin on top,no jelly on bottom,seperation of caustic going to the bottom followed by darker glyecern,not a very well defined seperation but it is going to the best on this batch.
Next up tommorrow DK we are going for another 100 gal high fatty acid coctail and will hope you help us thru this one start to finish.
5th time the charm (never had a good batch of high fatty acid)
Mr Lex
30 MCI Coach buses-29 detroit diesels,1 Cat

Cant say for sure but I think your processing at a bit to high of a temp. Methanol boils off at around 155F. I would say only bring temp to 130 for procesing.

Trc

Trc
thankyou for that insight,when doing single stage batches at low titration levels i;ve had very good success with a very Hot oil and lots of aggitation for about 1 to two hours,no problem with seperation,next batch tommorrow i;ll be down in the 130's

The same thing happened to me the first time I tried the acid/base method. I learned separation takes longer. Give it overnite. Maybe even a day. Note it is hard to tell the difference between the glycerine and the bio. The bio is very dark. There is a slight difference is viscosity. It is noticable but you have to look closely. If you give it time to separate the difference is very noticable.
The first time I let it sit about 4 hours or so and tried to drain. After draining ab out 15 gallons I knew something was wrong. I let it sit another day and it separated nicely.
Hopes this helps.

Lex,

if the oil titrates at the same (10). then use this

10-3=7*0.2=1.4mls of acid per liter
100 * 3.785 = 378.5 * 1.4 = 529.9 say 530 mls of acid don't use more!!! then titration might go up!

for methanol use 45.4 Liters or 12 gallons

heat the oil to 130 to 150. I find 150 is fine. make sure your reactor is designed to trap methanol while being open. a reflux column is perfect.

mix the acid and methanol

then add this to the oil. the oil should be dry!!

mix for 12 hours!!!
check the titration again? what is it? is it low enough for a NaOH base reaction. say 2 or 3? if not...DON'T added water. DON'T run the base stage!!!. STOP let it settle for 2-3 hours. you should not have to drain but it might help. drain about 6 gallons out of the bottom slowly.. it should look wet and watery..don't touch this its very acidic!!. I've check the ph its around 2.

remix the batch..don't add anything..just try the pump on. how long? depends on your reactor
check the titration again... low enough?

good now do the normal base reaction
5g + titration for NaOH
8g + titration for KOH

use 8 gallons of methanol if you didn't drain. or 14 if you did.
does it pass 27/3??? if not let it settle. drain some of the glycerin out and reprocess. repeat until it passes. then add 5% water for a prewash.

good luck

-dkenny

ps I've done a batch that started at 55KOH..2 acid stage

Monday july 7th
Couldn't start the week off with another high fatty acid mix with sulfuric acid and methonol disaster like the last two weeks
So, drew 55 gallons of top oil out of my 1500 gallon glyceren tank,titrated at 3,Did single step at 150 degrees with 7 gallons methonol and lye, mixed 1 hour, seperated within 30 min.
oil looks clear and glyceren very dark at the bottom.SUCCESS,EASY'I LOVE THIS BUSINESS
Tommorrow back to the Hell of acid esterfication with high fatty acid
Lex

DK
tuesday july 8th
new batch
1. 95gal
2. titration 27
3. oil 24hrs in heating tank@ 250deg
4.filtered down to 30 microns
5.cooling to 150 deg draining bottom 10 gallons

is this formula correct?
tit 27-3= 24x0.2=4.8mls acid per liter
95gallons x 3.785=359.5 liters x 4.8mls acid= 1725.6mls total sulfuric acid mixed into 11.4 gallons methenol
mixed into 95gal of 150deg oil
mixing for 12 hours looking for the majical titration 3

Lex,
with a starting titration of 27 you might not reach 3..but don't worry..I've done a batch that was 55 KOH..

process for 12 hrs..
if you'd like check the titration every hour or so. when it stops dropping this stage is done!!
if its not low enough then drain out about 50-60% of the initial methanol volume. or 50-60% of 11.4 gallons. drain slowly and you'll see a change near the end. stop..remix and check the titration again. it might drop 4-6 mls..
low enough??
yes - process with the base
no - use the same formula to determine the acid amount. for the methanol amount use what was drained. process for another 12 hours or until the titration stops dropping...settle and drain again..remix and check the titration..you should be good for the base stage at this point.

-dkenny

DK
wed july 9th
9am titration @ 14--down from 27
drained 6 gallons-- mixed(titration went up)
stopped mixing
titration 14-3=11x0.2=2.2x(95galx3.785)=791mls acid
stopped mixing @ 7:30 titration 8
settling overnight
What to do in the morning? is 8 low eneough?
does heating oil to 250deg to get rid of water cause titrtion to go up?
Can you use the 6gal of drained methonol/acid for a prewash on the next batch?
Does heat cause higher titration levels?

thursday july 10th
titration@ 9
drained 10 gallons of meth/acid mix
added 10gal+7.5gal methonol
added 4975g NaOH
mixed 2hours 150deg
NO SEPARATION !!

Lex,
NaOH titration of 9 is still way to high for me to confidently transestrify. Trying a base NaOH stage at 9ml titration, I would expect jello or nothing. Another acid stage would be in order to lower that titration down to a level below 7 for sure. Below 7ml NaOH titration your chances of conversion become much greater.

-Dave-

OK
I understand that a third acid wash would reduce titration "but" what now? titration is 0 and the reaction is going nowhere!
Also how would you produce 100gallons a day if your spending 3 days just in the acid esterfication process let alone trying to produce 400gal a day which is our goal.

quote:

Originally posted by LEX:
OK
I understand that a third acid wash would reduce titration "but" what now? titration is 0 and the reaction is going nowhere!
Also how would you produce 100gallons a day if your spending 3 days just in the acid esterfication process let alone trying to produce 400gal a day which is our goal.

LEX
Firstly are you positive the titration is actually zero,that is typically very hard to do and normally points to an error in the analysis.

If the titration is OK then how much water is there in your esterified oil, after all these acid reactions you may have water killing the reaction. I would take a couple of 1 litre samples and try test batches, drying one first. See what happens.

Your other question about capacity is simple maths, if it takes you 4 days to make 1 batch and you need to make 400 gallons per day then you need a reactor that can process a 1600 gallon batch.

SEPARATION!!
*there was success today on that last batch of acid oil.finally there was glycerin at the bottom and a dark oil at the top after a night of settling
*we changed to KOH today from NaOH and it was like a breath of fresh air,things started working much better
*processed two batches back to back with a titration of 20 plus with NO acid esterfication using a single stage process in less than 4hours with complete and fast separation!
*observations--- titration levels seem to bounce all over the place from the time you pick oil up to processing to final product,
I think we are dealing with FALSE or misleading titrations due to HUMIDITY and TEMPERATURE
*suggestions-- base your methoxide on a given temperature and relitive humidity and not on titration so much
*avoid using acid esterfication when posible,uses up to much time,produces water, stops reaction,uses more methanol