I usually mix my good oil with my not-so-good to keep my titration in the 5-7ml KOH range that I am comfortable with. But my good oil source basically didn't produce any oil all winter, so I have 60 gallons of 8-9ml oil, so I figured, good excuse to learn and use acid/base!

My first 1L test was a disaster...because I misread the directions! Used 2%vol acid instead of .2%vol (oops!) That increased the titration...obviously.

The SECOND 1L batch went from 9.4ml to 4ml in 3 hours...NEAT!

The 108L batch went from 9.4ml to 5.4ml in 3hrs, so I ran it (it was time to go to Easter lunch and I wanted to produce some diesel over the weekend!)

ANYWAY, the 3/27 revealed it was the MOST COMPLETE conversion BD I have ever made! No drop out, unwashed, with COLD methanol at 3/27, and just a little drop out at 6/27! But the methanol was 30F, if I had brought it inside and allowed it to warm, I suspect it would have dissolved almost completely.

I'm liking this Acid Esterfication stuff! And it will open me up to other oil sources around town that I have avoided due to their titration numbers.

Had to share!

What recipe did you follow for your reaction?

Ive been having so many soap problems recently Ive been thinking of the acid-base method too..

I think I have a bout a 3 gallon bucket's worth of soap in the bottom of my processor from my 40 gallon batch of oil that titrated at 18mL. I definately need to look into the acid base process.

Take us through it step by step. Any problems with a carbon steel barrel based processor, HF pump, & brass valves? (I have carbon steel and one stainless steel valve, but I have brass connectors on my static mixer.)

-Jim

Its really not hard. I don't know why I felt there was this mystique about doing it. I followed the Homebrew Acid-Base Biodiesel Recipes off this sight, specifically;

quote:

The FATTA method - Development by Kevin Tidball and Michael Fox

First stage acid catalyst (to esterify the FFA)
Oil 1000ml (1 litre)
CH3OH 100m (Methanol)
H2SO4 (conc. 98% 18M) 1-2ml
React at 48- 54C until titration falls to a minimum hopefully 2.6 ml could take longer than 2 hours. Greater levels of acid will raise the titration end point.

Second stage alkali catalyst (transesterification of the oil)
100ml methanol
6.4grams of NaOH
(3.5grams for catalyst + 2.9 grams for acid neutralisation if titration of 2.6ml achieved)
React at 48- 54C for 1 hour.
Settle and separate

So for the large batch it was;

1) warmed my oil to temp. (108L @ 130F)
2) slowly added .1-.2%vol 98% sulphuric acid (200ml) (I don't know if mine was this strength exactly, but it was the strongest, nastiest stuff the hardware store had, so probably close) to 10%vol methanol (10L), swirling frequently to prevent localized heating.
3) Slowly add acid-meth as I normally add the methoxide; (a little faster than 1L per minute) (the acid is so dilute (.2L in 10L; 2%), I don't think there will be an issue with processor metals.)
4) Recirculated on and on and on, pulling a sample and checking the titration every hour or so until it dropped to a level I was comfortable with.
Eventually, apparently, it will drop to about 3ml NaOH (4ml KOH?) if you let it go long enough. I plotted my Time Vs. Titration in Excel, and figured it would take 6-7hrs to reach 3ml (diminishing returns), so after 3 hrs @ 5.4ml, it was low enough for me and I ran with it at that titration.
5) Proceeded with base stage as I normally would minus the methanol used already (so 12%vol methoxide (12L), 7ml base+ 5.4ml titration (1340g), 3hrs, 5% water prewash (6L)).
6) Ran a 27/3 test; passed cleanly (I normally don't). Added 3 more ml BD, as reported above.
6) Separated glycerine.
7) And its sitting at home bubbling to remove methanol right now, so I'll see if I notice any differences during washing tonight and tomorrow as I get to it.

Excellent Thanks alot!

Ryan P.
great job.
that's what I started with last summer. maybe more people will realize that Acid/base isn't that hard. I found that, over several batches, I need varying amounts of acid to reach the end point. in the end I related this back to the titration. if you read under the sticky at the top you'll see my formula. I don't claim is original but derived from the FATTA.

water in the oil seems to destroy the acid process.

-dkenny

ex.

quote:

initial titration 15ml
final desired 3
15-3 = 12
12 * 0.2 =2.4ml of H2SO4 per liter of oil
this is higher than other methods!!

I thought the titration couldn't drop lower than the acid added. For 2.4ml/L, wouldn't the minimum possible be 5-6ml KOH?

Or am I mistaken? I am pretty new at this acid stuff!

that's what I used to think. then I forced to make several acid/base batches. low and behold I got ending values lower that FATTA said. some were lower than 3. but most end near 3. I don't why its possible it just end that way.

I always worried about using too much acid and raising the end point. with my formula I have seen that happen.

after you've done several batch you might want to rethink the upper limit of base only titration. I think i worked out If use the acid/base for titration over 7KOH I'll save money on KOH. the tradeoff is the process takes more time.

-dkenny

Well...the acid is producing water as it goes, right? And some glycerine, too? Maybe between the two, a base is formed and the added acid neutralizes itself with one of its own byproducts. Acids are highly reactive, probably wouldn't take much for them to breakdown and pair off as a couple neutral species.

quote:

Originally posted by Jim D:
I think I have a bout a 3 gallon bucket's worth of soap in the bottom of my processor from my 40 gallon batch of oil that titrated at 18mL. I definately need to look into the acid base process.

Take us through it step by step. Any problems with a carbon steel barrel based processor, HF pump, & brass valves? (I have carbon steel and one stainless steel valve, but I have brass connectors on my static mixer.)

-Jim

http://biodiesel.infopop.cc/eve/forums/a/tpc/f/41960555...911089422#7911089422

If you are using one of the TAH Static Mixers that I sell DON'T RUN H2SO4 THROUGH IT!

Also, even though they are rated for 250F I would not run them above 170F just to be safe.

-Jim