jdoughy, you asked what my methods were. sorry I could not post more the other day had to go to work and just got home. Still too wound up to sleep yet.

First I collected 4 samples of material hardwood bark mulch mostly oak probably red, maple chips from a planer, red oak planer chips, and burr oak chips from a chain saw. 2 samples of each wood were used the first was not pretreated in any way. The second was soaked in methanol. No soaking in clean bio was used so results could be thrown off. A control sample was checked for soap content by titration. Results were 4250 ppm. After soaking overnight the same titration was performed on all of the samples. All showed an reduction of amount of acid required to neutralize to yellow . But the oak samples when added to the iso/bromo blue solution instantly turned yellow indicating 0ppm of soap. So on a whim I broke out my naoh solution. The red oak required .5ml naoh to return to blue. Now I am starting to get more questions than answers. Do the chips really absorb the soap or does the tanic acid in the oak simply neutralize the alkalinity of the soap rendering the soap titration ineffective? Next I took bio from both oak samples along with a control sample and placed in 3 jars. An equal amount of water was added. Each sample was shaken vigorously. As expected a slight emulsion was formed in the control sample as well as milky water. The 2 oak samples did not emulsify but the water was quite milky and stands of soap were visible at the interface of the bio and water. I will also note the water from the oak samples was not as milky as the control.

Has anybody else done any testing like this? what are your results? What if anything could I have done wrong. My fear is that the chips are masking the soap, rendering any testing useless. I cannot risk any engine damage.
It has been a long day and I hope I have not rambled too much

Mike,

Good work here on the tests.

One comment.

quote:

Do the chips really absorb the soap or does the tanic acid in the oak simply neutralize the alkalinity of the soap rendering the soap titration ineffective?

As I understand, the chemical reaction that occurs when acid is added to soapy bio is acid neutralizes the base portion of the soap releasing an FFA molecule.

Your tests do indeed raise questions.

Here are some about the tests:

How much of the chips etc were added to how much bio?

How dry/wet was the wood?

Had the wood been seasoned for any time?

Were the wood and bio mixed at all?

Thanks for testing and reporting!

Hi,
Was it not suggested earlier to demeth the bio prior to the wood soak?

Why, then would we put demethed bio into methanol logged wood media?

Was the wood dehydrated of methanol first?

Perhaps a presoak/sacrifice in good bio instead of methanol would make a difference.?

Some of us are, and are planning to, follow the wood with resin, ect, hopefully extending the life of commercial drywash media. I will have Purolite. Another uses Thermax.

I'm abandoning this hardwood mulch from Lowes. It's just too dirty and moist. I'll try the mill, tack shop and pet shop and then sun dry the wood, when I find some.

Brian

Mike,

Nice testing. Not sure why soaking in methanol would be beneficial, but I believe Jehu did some testing along those lines.

quote:

as anybody else done any testing like this? what are your results? What if anything could I have done wrong. My fear is that the chips are masking the soap, rendering any testing useless. I cannot risk any engine damage.

For those who haven't already read these discussions, here are some links to read and get some background information on how this all came about:


http://biodiesel.infopop.cc/ev...1001332/m/2131054152

http://biodiesel.infopop.cc/ev...1001332/m/3081055582

http://biodiesel.infopop.cc/ev...1001332/m/1141082372

http://biodiesel.infopop.cc/ev...1001332/m/1781017752

I hope that helps.

I wish I had the resources to do scientific testing, but I guess I will have to leave that to others.

Mike,

As Andrew said the tannic acid is most likely converting some of the soap to FFA. It will mix into the BD, so you will have slightly acidic BD. It shouldn't be any problem burning small amounts of FFA's mixed with BD in engines that can burn BD. I think even resin produces slightly acidic BD. I know that Thermax contains sulfonic acid.

Eurocab

I could believe that except for the fact there appears to be a lot of soap left in the bio. If enough soap was converted back to ffa to go acid there should not be much soap left at all. What else could the white layer be if not soap

RE: the design I posted earlier. I intend to run the BD to a wash tank and finish woth water rather than a resin bed. What are you thoughts on this? Will washing get the released FFA out of the BD? the reason I was want to try the chips is to cut down on the amount of washing involved. Do any of yall suppose this can be achieved by the chips?

Mike,

That is quite puzzling. Without seeing a photo of your test, I can only guess that the white layer is either soap or an emulsion. If you are using kiln dried oak for the shavings, I would doubt that any sap is contaminating the BD.

The way I understand this is that the acid neutralizes the soap which is comprised of your catalyst (NaOH or KOH), FFA & water (produced from the reaction in making the methoxide). The soap is alkaline & when it is neutralized by acid (tannic acid in this case) it releases FFA's from the soap. Of course there probably isn't enough acid present to neutralize all the soap. When you have FFA in your BD there will be a slight emulsion formed when you shake it up with water. Over a small amount of time the emulsion goes away.

How long did you let your BD settle before conducting these tests? How much residence time did you allow for the BD & oak shavings? Do you keep it stirred up? How are you conducting the soap titration? How long did you let the shake test settle out?

I use red oak shavings regularly and do not have these issues. I allow my BD to settle after demething for a couple of weeks usually. Then I draw off the top of the settling tank and begin filtering. I usually have sparkly clean BD after about 12 hours of filtering.

Mike, good on ya for testing.

quote:

The 2 oak samples did not emulsify but the water was quite milky and stands of soap were visible at the interface of the bio and water. I will also note the water from the oak samples was not as milky as the control.

This is interesting. If you keep adding water to one of these samples and shake, will the "soap" remain or break up and dissolve? Some of it might be the white substance Jehu reported appearing in the interface upon using fresh sawdust. I have seen this as well. Nothing consistent to report yet on my part b/c I also demethed a batch too much and back reacted, getting some mg & dg so have nothing to compare currently. Was thinking of buying samples of gallic acid & tannic acid to play with. It's my understanding that tannic acid is broadly descriptive, having different forms & properties in different species. As Eurocab pointed out, I'm curious if red oak, et al act as a form of "natural resin." Tannin also appears to be antioxidant.

Is there enough acid available in red oak to acidulate soap?

Is the acid even strong enough to do so?

How much might it throw off a soap titration?

Will differences in tannin from... say, mahogany to oak, produce different results?

Should we even care? (Right now I'm using a large quantity of white cherry sawdust & it seems to work just fine, albeit taking a bit longer.)

Ton of questions, but gotta run. Thanks.

Wal,

quote:

RE: the design I posted earlier. I intend to run the BD to a wash tank and finish woth water rather than a resin bed. What are you thoughts on this? Will washing get the released FFA out of the BD? the reason I was want to try the chips is to cut down on the amount of washing involved. Do any of yall suppose this can be achieved by the chips

The wood shavings will definitely remove soap. I don't water wash so I am not sure about water washing out the FFA's. Most of the soap is sucked up by the chips anyway and therefor not converted to FFA's. I just burn them as percentage wise, there isn't a lot that gets converted.

quote:

It shouldn't be any problem burning small amounts of FFA's mixed with BD in engines that can burn BD.

Yes, but ffa is more attractive to water and less stable than BD. Also, he could easily be above ASTM for TAN. Less is better, IMO.

Well that is good news. I am in the process of finding the red oak chips and we shall see when I get it done.

eurocab do me a favor and take some finished bio add water . Shake like there is no tomorrow. Please let us know what happens.

the red oak was kiln dried but the burr oak was taken from a log cut down a year ago and still damp results from both were similar. When I get time I will wash some more. Got to get my corn in today. Honestly I havent even looked at anything in the garage since saturday morning. Too much to do, so little time, and then work gets in the way.

Just an idea but if people got together agreed on a procedure eg so many grams of chips so much methanol soaked for so long etc then titrated the sample and posted the results it wouldn't take long to work out which woods were acidic.

Got lucky and found a source for chips on the route from work to home. It is a mix of red oak, hickory and cherry. He wants 15 bucks for a 55 gallon trash bag. I am going to stop by today and get a bag but I aint done haggling over the price. Think I might get out of swing and brew me some this weekend to see what I get. I am getting that"I am fixin to build something" feeling all over again.

Wal,

I would definitely haggle over the price. Usually wood shavings are dumpster fillers. Some large shops give their sawdust to recyclers. They sell it to companies that make chip board and medium density fiberboard.

Mike,

quote:

eurocab do me a favor and take some finished bio add water . Shake like there is no tomorrow. Please let us know what happens.

I have been doing that for about 10 months now. What happens is it mixes up and then the water settles to the bottom and after a little time, the BD clears up. I usually set it outside in the sun so the water will fall out faster. If there is soap in it, it is usually not much and it is evidenced by the small white line between the BD & the water. When I use virgin wood shavings, there is no soap evident after a good shakemup and it takes a lot less time for the water and BD to separate. When I am using used wood shavings, it's a coin toss.

Again, I am allowing my demethed BD to settle for usually a couple of weeks. This means that the BD is not nearly as soapy as unsettled BD. I pour shavings into a tub and stir them up several times over the course of the day and then start the filtering through my system and by morning the BD appears to be clean. I then run it through the resin columns and final filter through a 1 micron filter and into the tank.

Another advantage to allowing the soap to settle out first is that you can take the soap from your settling tank add a little bit of acid to it and end up with a bunch of FFA's to convert to BD using the Acid/Base method. I just started doing this and I add about 10 gallons of FFA's to 22 gallons of oil. A lot of the FFA's will esterify during the acid stage. You can also crack glycerine and do the same with it, thereby reducing the amount of waste product. You end up with purer glycerine for soap making perhaps.

If Mike is getting soap he's doing something wrong. I'm making the best biodiesel Ive ever made merely gravity filtering thru mahogany sawdust. You have to use a lot more than you would if you were using resin, amberlite or magnesol, unless you want to go to the trouble of changing it frequently, but I run half a dozen 150L batches thru 20 litres of sawdust and its still giving crystal clear biodiesel when I change it - it costs nothing.

I would guess that Mike is not using enough wood or is forcing it thru too quickly, or maybe the wood isnt fine enough. Sawdust is best, shavings work fine but of course a lump of wood floating in raw biodiesel isnt going to have much effect - so the finer the better.

I hope this is not a stupid question, but where does the soap go? In a water wash, it goes out with the water...

UFO,

If you settle the BD after demething the soap goes to the bottom of the settling drum. The rest is absorbed by the wood shavings/sawdust. The tannic acid may convert some of the soap to FFA.