This has been a little experiment using a breathalizer to determine methanol content.

In a previous post I had stated:

quote:

I think I will try it in a 500ml jar first. Maybe I can catch all of the air output stream and relate a BAC reading with methanol content.

I said before that I waved the tester over the settling tank and got a .02. This was without bubbling air and is not an acuurate reading.

I know it wont be exact but for the human body,

.01BAC = 1 cg of alcohol /mL of blood.

This has to do with Liquid Vapor Equalibrium as well as Daltons Law, Ideal Gas Law and Raoult's Law. If I can get the proper ratios and values for equilibrium of methanol and bio then we can get a real conversion with more acurracy but until then..

1 cg/mL * 1g/100cg * 1000mL/L * 1cm3/.7918g * 1L/1000cm3
Density of Methanol
After conversion factors:

.01BAC = .01263 L of meth/ Liter of solution

so the forumula for toal methanol content:

Methanol = (BAC Reading) * Volume of BD * .01263

My very Inacurate .02 reading would indicate that there is .0253 L left. I'm sure that the only way to get an acurrate reading is to bubble air through the BD and force all air through the detector.


Now, Lets throw all of the above out as the only useful thing there is the conversion factor.

ASTM is <.2% by volume right?

Lets do away with the actual volume number and go strictly for content percentage.

If there was an exact relationship between Blood Alcohol Content and Biodiesel Alcohol content then:

Meth% = BAC * Unit Conversion Factor * 100

Meth% = BAC * 1.263

So:

BAC = meth%/1.263

I wish i could test this as it would mean that a fresh mix of oil and 22% meth would blow a 17.42!

My meter only goes to .40 so no luck there.

However, If we want to target .2% for ASTM then we need to know what BAC to shoot for.

BAC = .2/1.263

BAC = .158 My detector will detect this.


Now Producer has been gracious enough to give us some stats that the soap dropout happens when methanol is between .15 and .10 so we can solve for BAC

BAC reading = .15/1.263 = .119

BAC Reading = .10/1.263 = .079

So, By my calculations if my biodiesel can drive then the soap should drop out! That is of course assuming that there is a relationship here in which case I want credit for converting Blood Alcohol Content to Biodiesel Alcohol Content.

I will test this weekend and report back. Let me know if I'm wasting everyones time here.

Well Here are the findings from the small scale test.

I took a 500ML flask and filled it with 450mL of Bio from the top of my settling tank. This bio has been settling for 1 week. To the left is a quick wash test with Distilled water.


I then used an aquarium pump and a small buble stone to force air into the mix and then captured the air from the flask to force it through the tester to get a reading.



I took readings every 15 mins and it took about 3 hours to reach the desired .08.
My calculations said that at .08 I should be less than .1% methanol content so I stopped there and instantly I started seing soap drop out.






I settled for 8 hours and performed another wash test. The water is clear!

Very nice. As I mentioned on your other thread spray circulating accomplishes the same thing. I use an NT pump and spray through a restricted head tha splashes/agitates the BD on the surface of the settling tank. I use a centrifuge to capture soaps. The centrifuge usually won't collect anything unless I have spray circulated in the open top tank for a few hours.

Very impressive c-snap.

With further proofing of protocols could prove to be a reliable low cost test for homebrewers.

Well done.

Well Done!

What was your start reading with the 450ml sample?

I'm guessing that after finishing with the GL that there is what 300-400 ml of methanol that still needs to come out of a 150L batch.

Hello Rick,

Just got the UPS delivery from you (Blue indicator) so now I can try and gather everything to perform soap titrations.

The start reading was H which means it was above .40BAC which should mean it was above .50% methanol which would mean that there was at least 500mL in my 100L batch.

I decided that in the spirit of things I would drink too! I found that the BAC indicator is way off if you measure within 20 minutes of taking a drink.
I took 5 measurements every 15 minutes 3 of them were on bio and were ~1-2 min's apart. The first is the BAC reading, the second number is my hypothetical conversion.

Here is a transcription of my logs:

***Log file is attached with better formating

Time Christine Mike BD1 BD2 BD3 Notes

2145 0.0 .01 H/? .32/.404 .33/.417 Sample taken. Started Process and started my first drink.
2200 0.0 .28 H/? H/? H/? Knocked over flask before taking BD Measurements...(Maybe my BAC reading was right)
2215 0.0 .20 .04 .15 H/? Retaped Lid after 2nd test. Electrical tape started leaking due to incident at 2200
2230 0.0 .15 H/? H/? H/? -
2245 0.0 .02 .38/.480 .33/.417 .31/.392 Noticed that bubbles on top of bio are taking up ~ 1/2 the volume as before
2300 0.0 .02 .30/.379 .27/.341 .26/.328 Solution apears slightly clearer
2315 0.0 .24 .24/.303 .21/.265 .20/.253 Made another Drink for myself..
2330 0.0 .26 .17/.215 .16/.202 .16/.202 Bumped flask
2345 0.0 .13 .14/.177 .14/.177 .13/.164 -
0000 0.0 .06 .13/.164 .11/.140 .11/.140 Took 2 pictures
0015 0.0 .15 .10/.126 .10/.126 .10/.126 -
0030 0.0 .14 .09/.114 .08/.101 .08/.101 Took 2 more pictures - Stopped Drinking
0045 0.0 .06 .08/.101 .07/.088 .08/.101 Shut off air pump and observed soap in solution. Resumed test
0100 0.0 .05 .06/.076 .06/.076 .06/.076 Things are going good so Hell it, Made another Drink
0115 0.0 .13 .05/.063 .05/.063 .04/.051 Open Top, Run for 5 minutes to ensure that any vapors trapped in upper headspace of flask
could evaporate. Highly visible soap! Took some pics and took sample for wash test lots of
precipitation observed on bottom of flask. Wash water is much clearer. Took Pic


The following morning at 1030 I performed another wash sample and the water was extremely clear and so is the bio.


Hmm, It is formated much nicer in the post or edit field but does not keep the spaces when viewed on the board.

Sorry


It may be easier to read the attached log file. I pasted everything in there for easy vieweing.

Log.txt (3 KB, 24 downloads)

quote:

As I mentioned on your other thread spray circulating accomplishes the same thing.

I am not spraying my bio into the headspace on my GL-1 processor. I think this may be the root of some of my high methanol content. Spraying should allow the methanol to more readily flash to a vapor. I will build a spray nozzle for my setup and then rerun to see how easily the methanol comes out. I should probably do some sort of test if it works to compare speeds of bubbling vs spraying.

Graham is spraying and says that a fast smooth flowrate is "Slow and Boring" I bet not only is his statement true but sprayin allows not only faster recovery but also a higher percentage of recovery. I think my process is reaching its max recovery or equalibrium point well before it would if I sprayed the mix into the headspace.

Thanks for the info.

Make sure you keep the restrictions on the nozzle to a minimum. Too much back pressure can have a negative effect on the venturi.

quote:

restrictions on the nozzle to a minimum. Too much back pressure can have a negative effect on the venturi

Thats my goal.. Please have a look at my other post

quote:

Originally posted by cntsnap:

I am not spraying my bio into the headspace on my GL-1 processor.

Not spraying the BD into the headspace above the bulk liquid in the processor could be a major reason why your methanol removal results have not been what you expected.

How do you return the BD to the processor?

quote:

spraying the BD into the headspace above the bulk liquid in the processor could be a major reason why your methanol removal results have not been what you

Thats why I built this nozzle

I would greatly appreciate your thoughts on it.

Currently I just recirc and dump back into the top of the reactor tank. It is just an open port with no spray pattern.

Hi Paulus, I fixed the pics... Would you mind editing your post to remove the url?

Thanks

quote:

I will test this weekend and report back. Let me

I should have posted this sooner.

Just so you know,

This is accurate and it does work. I added a known amount of methanol to a 100ml sample of .02 biodiesel and got the expected reading on the breathalyzer.

This was tested and verified using a 100ml solution that measured a .02 BAC reading on the breathalyzer. I then added 0.25ml of methanol which is .25% by volume of the sample. This should cause a reading of .218. The measured results held true to the predictions of the calculations using my conversion factor for BAC.

I use this test and like it alot. Its a great way to field test your biodiesel before sending it out to the lab. Plus you can bubble longer if you need to. The thing you have to be wary about is that the breathalyzer either needs to be calibrated at least monthly or you have to buy another.