Need some wisdom.
My current oil supplier started stretching his oil changes and subsequently the oil went from 4.5g KOH to 15-18g KOH. 1st single stage batch with new oil yielded little fuel, so I tried the 2 stage system.

100L oil titrated at 18.
18 titration - 3 desired = 15 X .2 = 3ml sufuric acid per Liter X 100 L (oil) = 300ml of sufuric acid. Heated oil to 125F, mixed 12L of meth (60%) to 300ml of acid and added over 5 mins. mixed for 30 mins, then mixed and let set 15 mins each for the next 20 hours. Titrated the oil and it's at 18 still.
Sufuric acid is 93% I believe. Have I missed anything?

I'm having a hard time once I get past the acid stage, but I can get that part to work. So....

Everything sounds good to me, except that I don't know what you mean by "mix." If you just stir it, that may not be enough agitation.

Second (probably more important) point, 20 hours is a long time. Are you maintaining a high temperature? 125F is about where I start, but it's because the combination of a strong pump, an exothermic reaction and a well-insulated reactor means that after about 5 hours the 200L or so I have has gone up to about 140F, which is a good temperature. You'll want to be in the area of 135-145F for the duration of the reaction.

Another possibility...are you losing methanol to the atmosphere?

Still another possibility: how are you obtaining the sample to titrate? Could it be contaminated with unreacted oil?

what was the water content of the oil?
the acid stage requires dry oil. say something less than 0.5%.

are you titrating after its mixed or settled? it should be done mixed.

time - depending on temps the times can run long..very long.. I have a batch that I started at outdoor temps(85F+), no heat. started at 26KOH its now at 11 KOH after 28hrs of processing. continuous pumping not cycling.

-dkenny

I'm using an Appleseed processor, so mixing means running the pump for 15 mins, circulating the oil/meth/acid in the heater. It mixed for 15 mins, sets for 15 mins, mixed for 15 mins, set for 15 mins for the past 20 hours. Temp wise I don't know. It was 125F when I started, set the timer and left. It was atleast 100 after 20 hours.

Don't think I'm losing meth, seems sealed pretty good. when I went to drain there was a good vacuum on the tank as usual.

Sample obtained through a drain. I drained a pretty good bit of oil before I took a sample for titrating. After settling for 2 more hours it's still at 18.

I didn't test the oil for water, but did heat it to 140F for 20 hours with a fan blowing on it. The oil I normally get is pretty dry, so I didn't test this batch and heated it longer than expected.
I titrated right after mixing and again after it settled for 2 hours, same results

Drip a sample onto a hot (300-350F) skillet, and see if it bubbles. If you don't get bubbling, it's dry. Water is the enemy, in either acid or base processing.

Still, I'd expect at least some change in titration, even if there was some water in it. It just wouldn't work as well. I wish I could help.

can I test a sample of the oil/meth/acid? Don't want to blow anything up.
I'll titrate it again when I get home today and if nothing guess I can redo the acid stage. Any changes from the original recipe for redos?

titration must done mixed.
use caution when handling the stuff that drains after its settled. it will be acidic. I have measured a ph of around 1.

so with it mixing...if its settled let it mix for 20-30 minutes before titrating.

drain 500ml out..drain another 500ml out and titrate this not the first draining.

if you run a 2nd stage.
let it settle
drain about 6L of water/acid/methanol
use about 3 L of methanol and 150ml of acid
let settle then drain again.
mix then titrate
hopefully all goes well then run the base stage(s)


good luck

-dkenny

quote:

Originally posted by chris023:
can I test a sample of the oil/meth/acid? Don't want to blow anything up.
I'll titrate it again when I get home today and if nothing guess I can redo the acid stage. Any changes from the original recipe for redos?

If you're talking about hot testing for water, the answer is no. Not only would this be potentially bad for your health, but methanol would boil off before water did, possibly giving you a false positive to this test. I apologize: I should have been clearer. What I was describing with the skillet test was for oil to see water content, not a test for a partially-completed batch.

quote:

Originally posted by greiswig:
If you're talking about hot testing for water, the answer is no. Not only would this be potentially bad for your health, but methanol would boil off before water did, possibly giving you a false positive to this test. I apologize: I should have been clearer. What I was describing with the skillet test was for oil to see water content, not a test for a partially-completed batch.

I figured you meant testing the oil before starting, but I was wondering if it was possible to test what I have, guess not. thanks

quote:

Originally posted by dkenny:
if you run a 2nd stage.
let it settle
drain about 6L of water/acid/methanol
use about 3 L of methanol and 150ml of acid
let settle then drain again.
mix then titrate
hopefully all goes well then run the base stage(s)
-dkenny

Ok, I went to drain and it looks like oil with meth/acid. should it look clearer?
I drained about 6L of whatever was on the bottom. Before I add 3L of meth 150ml of acid I have a couple questions: do I need to heat the batch first and if so to what temp?
you say add meth/acid then let settle again and drain, then mix and titrate. do you mean add, mix for a couple hours, settle drain 3 L, mix again then titrate?
Sorry for the many questions, but I'm on unchartered ground.
Thanks,
Keith

quote:

Ok, I went to drain and it looks like oil with meth/acid. should it look clearer?
I drained about 6L of whatever was on the bottom. Before I add 3L of meth 150ml of acid I have a couple questions: do I need to heat the batch first and if so to what temp?
you say add meth/acid then let settle again and drain, then mix and titrate. do you mean add, mix for a couple hours, settle drain 3 L, mix again then titrate?
Sorry for the many questions, but I'm on unchartered ground.
Thanks,
Keith

if you drain and it worked as planned it'll very watery. this is methanol/water and acid. if you drained too much the stuff will separate into 2 layers. oil on top

if you don't reheat the mixing will take longer.


otherwise one of my better oops..
yes mix then add the 3L and acid..mix more several hours...12+ maybe
you can titrate during this but be sure to drain enough of the drain to remove and left over from the previous draining. then take another sample from testing.

if the titration drops to around 3..let the mix settle for a couple of hours then drain more water/acid/methanol out..

since you drained keep track of how much you drain out you'll need to add back this much methanol to the base stage. so for you need to add 6L more to the normal base stage amount.

-dkenny

quote:

Originally posted by dkenny:
yes mix then add the 3L and acid..mix more several hours...12+ maybe
you can titrate during this but be sure to drain enough of the drain to remove and left over from the previous draining. then take another sample from testing.

if the titration drops to around 3..let the mix settle for a couple of hours then drain more water/acid/methanol out..

since you drained keep track of how much you drain out you'll need to add back this much methanol to the base stage. so for you need to add 6L more to the normal base stage amount.

-dkenny

OK, after draining about 6L, I heated the oil to 125F, mixed 3L of meth and 150ml of acid, then added it to the oil. mixed non-stop for 14 hours, settled for 8 hours. when I got home from work I drained 3L and mixed for 30 mins. titrated at 14g, down from 18. the oil was still at 115F. Question is do I make the base now or mess with another acid stage?

you'll need another acid stage.
sorry if I wasn't clear but titrate the mix before you let it settle and drain. this way you can tell if its done what you want. if not you could process more.

to back this with an example.
several days ago I start a batch
no heat
titration 26 KOH
use the methanol and acid amounts using my method.
first 24 hrs it dropped to 15
the next 12 hrs it dropped to 10
overnight it dropped to 8
this is continuous pumping
notice it drop alot at first then the dropping rate slowed. I think the lowering would have continued but I turned off the pump. I'm expecting a 4ml drop after I drain the mix

keep working at you'll get it.

-dkenny