quote:

ournal Article in Renewable Energy 28 (2003) 939-948

cut and past into a net search box and whala it is amazing what you can find.

I think this is what your looking for. Yes it has to be downloaded. 10 pages

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Tim, I was so intrigued with using baking soda that I did a sample today. This is 6 hours in full sun after being shaken hard in to an emulsion. Yeah it sure bubbled up...AND OVER! I'll give it a week to clear but the oil was taken from the top of a cubie set for disposal. I'm not expecting miracles.

wvo_and_baking_soda.jpg (70 Kb, 88 downloads)

It will evolve carbon dioxide gas, so probably worth using a larger container.
Also add the bicarb slowly.

After the first hard shaking and settling, the baking soda formed between the water and oil level. I shook it again then after a while the baking soda blobs started to rise (as the oil heated up in full sun) until they were on top. It wasn't until a few hours later did I see that it bubbled over. The BS bubble stuff on top reminds me of the aerosol can of spray foam to fill cracks and voids.

I am confused, did you first dissolve the BS into the water, sounds like not. I tried adding the BS powder directly into the oil/water, it did not work. I suspect the BS got coated with oil on its way to the water in the bottom of the barrel, the oil coating kept the BS particals from dissolving into the water. The BS seems to need to be dissolved into the water prior to mixing to get it to react with the acids bound in the oil.

That much foaming that fast would seem to indicate a LOT of water soluable acid for the BS to react with, with my one pound of BS dissolved into 5 gallons of water and then the BS/water stirred into 45 gallons of warm oil it usually takes at least over night to see bubbles, even longer to make foam. I usually get around a 4 inch layer of foam on the top of a barrel of warm oil after 3-4 days if acid is present, sometimes I dont get anything but a few bubbles, depends on the quality of the oil, unfortunatly, you can't tell the acid content by looking at the oil. Clean looking thin oil from the top of settled cubees usually makes the MOST foam, it even sometimes makes won't-seperate emulsions, FFA's should be lighter than oil so will end up on the top of the liquid, they are what the BS converts into soap, lots of FFA means lots of soap, lots of surfectant soap will make an emulsion that won't easily seperate by gravity alone.

Anything new since July? And Tim Cook, what if you remove as much water/bs as posible when you 1st mix with WVO. Seems like the acid in the water is making the BS bubble. So if the 1st settling of water/BS is removed, then a greater portion of the already completed reaction is removed. I would think once the water/bs settled out , that the wash proccess has been performed & no longer is a benifit. (except sitting in bottom of barrel making a bubbling reaction) acid in the water & BS. Or does the gasses bubbling up, help something? ( the gas is carbon dioxide? )

Hey,

I have some off spec biodiesel. Aren't there techniques like this baking soda routine that will precipitate oout the soaps or ffas. I'm at like 2.0 mg KOH/g but need to get to the ffas to budge.

In biodiesel land I tried acid esterifucation and also a mild (.033%) NaOH (aq) solution 1/3rd vol. 3x and rechecked ffa...still llike 1.5 mg KOH/g.

Tried magnasol...didn't help much.

Any WVOer make a suggestion?

bbiofuels@yahoo.com
80 300D Wagon
81 300SD Turbo
87 300D Turbo
95 F-350 2X4 7.3 Turbo-Diesel Magnum (propane)
66 Volvo Amazon wagon

If BS and the acids in the oil create C02, H2O and soap,
what would happen if I pass my oil/BS/water mix through a centrifuge?
I removed most of the water that settled to the bottom, but still have some water/BS suspended in the oil.
I am currently passing the mix through a centrifuge and i am getting 3-4" of froth on the top, and smoke (water vapor?) coming out of the centrifuge.

If I leave the centrifuge running, will the soap eventually go away? the water/CO2 should smoke/vapor out, but what about the soap?

Thanks,
Danny

Soap creates an emulsion that is so strong the CF may not remove it. Settling (warm) for a very long time, or a very hot flash evaporator may be the only solution. This is the biggest drawback to adding BS.

I mix the BS water with the oil and let settle/bubble for a week, depending on the amount of acids and/or FFA in the oil the bubbling may stop sooner than a week. The amount of soap produced depends on the initial FFA content, unless there is a lot of soap the oil should settle into nice visably clean oil over the second week of settling. If the oil has not started to seperate and produce a clean layer of oil on the top of the barrel by the 3rd day after bubbling stops I stir 4 cups of household flour into the barrel, this has so far always produced the start of seperation within the next 2-3 days, wait another week and pump off the top oil. It ain't fast but it is cheap.

emiperformance -- Confused, did you allow any time for the BS to react with the FFA's, BS is so mild of a caustic that it will take a few days for the reaction to complete, you can't simply mix everything together and then immediatly run it through the centrifuge, not that easy. My experiance has been that the soap drops out of the oil and sets as a layer above the bottom water but under the oil. Bonded water is part of the soap producing process so I would think soap should be heavier than oil and seperate out over time with static gravity but may not be heavy enough to work well in a simple centrifuge as it is heavier than oil but lighter than water, don't know, needs testing.

Tim,
I mixed 5 gallons of water with 1 pound of B.S.
let it sit for a week, it brought the titration down to 8. I added another pound of B.S. and let it sit for another week.
I had a SLOW seperation with the one pound.

took about 6 days.

After I added the second pound, it seperated within a day.

Do I need to make sure all of the soap is out of the oil before using it to make Bio?

Thanks,
Danny

Hey Tim,

Long time...

I have a paper towel question for you (or anyone really). Does anybody have a (good) guess of the micron rating of brown paper towels? the kind used in public bathrooms.

I've been using them wrapped around 1 micron spun filters and they reduce the flow considerably more than standard, kitchen-variety paper towels. But they sure do make the spun filters last a loooong time.