I did a search on the word acetic and found nothing in this thread since Nov 1.

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Originally posted by neutral:
I did a search on the word acetic and found nothing in this thread since Nov 1.

Posted 30 November 2005 04:36 PM by biodavid

quote:

Optional Step : add about 5 ml of acetic acid for every Liter of biodiesel and recirculate for 15 minutes. Let settle for about one hour, then drain out the settled acid and any precipitate from the bottom valve. This will precipitate out any unused KOH and will break apart any minor emulsions.

Don't you just love the quirky search engine?

-Jim

Yesterday (or was it this morning?) I posted about how I screwed up and ended up with 9000+ ppm soap in my diesel and only or so gallons of glycerin from 40 gallons of oil and a total of 13 gallons of methanol.
I put 5 gallons of glycerine back in and circulated for an hour (cold bio at 60 degrees or so.) Then I let it sit overnight. This afternoon I put the pump on a timer and let it go for about 2 hours (58 deg F.) A couple hours later I went out and drained off 10 gallons of glycerin . That 10 gallons plus the 2 gallons that I still had from the first time makes 12 gallons! I pulled a sample of the biodiesel and soap tested it. It is now down to just under 3000ppm. I think I am going to put in the other 2 gallons and maybe 3 gallons that I have left from an earlier batch and circulate it a couple of times for a couple of hours each time and see what happens. Anyone have any idea what is going on? I'm just hoping to get the soap content down to keep from going broke using Magnesol to wash!

-Jim

you could of course just use water! Perhaps use water on this batch to get it out of the way and then get back to experimenting with magnasol on a normal batch.

Yea, I know...

I got such a dramatic reduction by using the 5 gallons of glycerin (>9000ppm down to <3000ppm) that I think I will use the rest of my left over glycerin first. If I can get it down to 1500ppm or so then I am back in the range of standard magnesol application.

What got me was how little it helped to reprocess 43 gallons of biodiesel with 3 gallons of methanol, 200g of NaOH, and no glycerin. And how much just adding 5 gallons of the original batch's glycerin helped, even when circulated cold. (Another 5 gallons dropped out, for a total of 10 gallons on the second drain.)

-Jim

acetic acid does three things
1 stops the reaction
2 precipitates out unreacted catalyst
3 separates out soaps that have already formed (breaks the emulsion)

hope this helps. you could use any acid like myriatic, or sulfuric, however, I chose acetic due to it's more friendly msds and that it is cheap and organic.

jim, has your batch emulsified, or does it look like good fuel...until you wash it and it turns into milk? I've found heat and acids to be the best way to break an emulsion.

If it looks good, but doesn't emulsify till a water wash test, try setting aside a couple of jars the bio and adding different amounts of myriatic acid to each jar (2ml, 4ml, 6ml...), shake, and observe how much precipitate settles out. then scale up to your big batch when you figure out the right ratio

sorry to post three in a row, wanted to address any questions. magnesol is extremely polar and attracts FFA's, using the acetic acid rinse has been negligible as far as FFA's due to this property. ...aside...FFA's apparantly have a higher lubricity than low ffa bio, perhaps this could even be beneficial in low bio blends. who knows.

No problems with an emulsion. It is a good batch. Nice, clean line between bio and glyerin. The bio is a little cloudy, but that could be due to the high soap content. It should make a good batch, I just don't want to use 10-1/2 pounds of magnesol (3.6% by weight) to treat the 40 gallons of biodiesel. Gets kind of expensive that way.
What concentration of acetic acid are you using? 5% supermarket vinegar? 56%? Or Glacial (99+%).

-Jim

Personally,

I think its a mistake to add any kind of particulate media to a fluid system.

It would seem better to put the Magnesol media in a filter vessel with something like a 1 micron oil permeable membrane filters at the top and bottom of the vessel (to retain the media in the vessel) and then pump your de-methanol'd fuel through this filter.

Yes, flow rate will be an issue, however, this can be overcome with the right pump etc.

FilterVessel.JPG (131 KB, 103 downloads)

What is the difference between mixing and flowing through a 1 micron oil permeable filter and preloading the filter with magnesol and then flowing oil through it?

All of the filter media stays together as opposed to being randomly distributed throughout your system - clogging up valves, elements, elbows, etc. etc. etc.

It makes it easier to change and service.

Jim D
Did you test for residual catalyst when you tested for soap? I am wondering if this might be why there was more glycerine. Have you done a soap test on your glycerine?

quote:

acetic acid does three things
1 stops the reaction
2 precipitates out unreacted catalyst
3 separates out soaps that have already formed (breaks the emulsion)

I test for unreacted catalyst in my bd and never find it unless I use twice as much catalyst normally used. Also, since we are not introducing water to the bd, we have no emulsion, so I do not see a need to add acetic acid to the bd. Even if the magnesol does remove the ffa, when you add acid, you are most likely reducing the yield.

quote:

do a wash test ( in a small jar add 50ml of the biodiesel, and 50ml of water, shake, wait for separation…hopefully it takes less than 10minutes. Make sure the wash water is completely clear, meaning no soap, before proceeding to the final filtering)

I test for soap before magnesol and after to see how effective it is in removing the soap. Since I have changed how I filter, I do not find soap in the bd. I also take some and shake it with some water to see what the results look like. I do get very quick separation, but the water is never completely clear. It is usually slightly cloudy.

quote:

Did you test for residual catalyst when you tested for soap? I am wondering if this might be why there was more glycerine. Have you done a soap test on your glycerine?

No I didn't. For a minute there I thought I didn't have a sample to check but I believe I have a sample of biodiesel with glycerin in the bottom form after the second processing and from after just cold pumping with 5 of the 7 gallons of glycerin in the processor.

On a different note, man I screwed up again. I think this batch may be cursed. I went ahead and put the other two gallons of 1st run glycerin and about 3 gallons from an earlier batch in the processor last night. I ran the pump for 3 hours. This morning I went out and fired up the pump again and turned on my torpedo heater to get the processor up above the 45 deg F that it had cooled to. Then I got stupid and went inside to get back to work. about 2-1/2 hours later I remembered the heater was on. I ran out an shut it off. The mix was up to 152 deg F. The vent line off of my relief valve was not sitting outside, so I think I sucked down a little methanol while I was in there also. I feel fine. I feel silly sitting here drinking a beer at noon. Oh well, it's 5 o'clock somewhere!
I just reread the MSDS on the methanol and am reminded at how nasty this stuff is. So far (45 minutes later) I'm not showing any of the signs of exposure, but if I keep being stupid I'm going to end up with the systemic problems. It's time to review my handling procedures and set up better safety systems.

As far as the BD goes, I wonder if I just boiled off all of the methanol and reversed the reaction? I've got the heat off, the pump running, and the insulation off to allow the barrel to cool down faster. I think I'll go out and run a fan to vent the building and cool the mixture.

I considered not posting this, but I think we are all better off when we post what goes wrong, not just what goes right.

-Jim

Jim, I would not worry about the short term exposure, Having said that you actually did the correct thing to eliminate the Methanol from the body (drink ETOH.) Methanol intoxication almost mimics Alcohol intoxication (slurred speech, nausea, vomiting, staggering gait) are some of the signs/symptoms of acute intoxication. However as you know you can be blinded and under certain conditions cardiac and respiratory arrest can occur. When I use Methanol, I ALWAYS have my area vented VERY well (open both the garage door and side door to get a cross wind into the area where I work) I also use a fan and an open window.

HTH

Ian

Same for me on the precautions. I ran in without thinking to kill the heater without ventilating. Normally I would have opened the door and turned on the fan that is right by the door to ventilate before I go in.
I never felt any of the listed side effects, but had the beer just to be safe.
-Jim

What I do to prevent this is that anytime I am near Methanol I have a few beers just to be safe . Even if the methanol is in a sealed container there is no sense taking chances .
Shannon

Jim D, your best procedure would have been to take a couple of deep breaths in the outside air then hold your breath and walk calmly inside to switch off the heater, then outside for the next breath.

You can do a great many things in the two minutes you can easily hold your breath.

Anyway you didn't need to worry as you didn't boil off any methanol. 152 deg F is 67 deg C. My experiments have shown that you have to get to 77 deg C to boil off methanol from a biodiesel reaction if using a closed reaction vessel, as you were.

Yea, I know.

Actually I just reached in an unplugged the whole thing. At that point I should have left the door open, turned on the fan, and thought about what I needed to do next. Instead I rushed in half expecting to see oil/biodiesel everywhere.

Hindsight...

Jim