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Originally posted by Ant:
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They all work because the wood has an affinity for wood alcohol, methanol, and draws it out of the bio; Jehu has noted this before.
Without the cosolvent of methanol the soap drops out of the bio and is then trapped in the fibrous surface area of the shavings or dust.
I believe the sawdust is absorbing the methanol which then redistributes to even out the gradient and is sucked out some more. This continues untill the soap comes out.
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I dont see how this works. What if the fuel is demethed before the chips? From what I have seen the more methanol in the fuel the shorter the life of the chips.

Without the cosolvent of methanol the soap drops out of the bio and is then trapped in the fibrous surface area of the shavings or dust. Wink
 
Registered: January 22, 2010Reply With QuoteReport This Post
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I demeth as far as can. In a week or so all that snotty stuff falls below my standpipe.

On my testing, that week old fuel looks great and clear, but it tested @ ~290ppm soap titration.
The first pass thru the ppm was cut in half. After 2 hours circulation it was 60ppm. After 6 hours circulation it was still 60ppm.
I dont think I get all the methanol out with just bubbling and a heating element.

Also on circulation, I've found that all fine dusty stuff in my shavings find their way to the top of the shavings in the drum and stay there. I like to think the fine stuff is helping and I dont have to sift the shavings. The resulting fuel has a clear particulate free appearance and breezes thru
1 micron #2 bag filter.

My wood shavings 'poplar' from Koetter & Smith in Indiana. (Thanks Fabricator.)

And IIRC, that first pass sat static in the shaving with the bottom drain closed for a time.
I think I was making sure everything would fit with out overflowing should the drain clog, but that was never an issue.


1996 K2500 4x4 6.5TD
 
Location: Southern Indiana USA | Registered: June 20, 2008Reply With QuoteReport This Post
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it is puzzle for me that why i fail shake em up test i get cloudy water my bio is crystal clear and i have done about 500L so far.i have 200L barrel full of saw dust /chip wood.last time i filter the same bio twice and the water test was much cleaner but had some cloudy sort of bubble between bio and water. any explanation please
 
Registered: April 02, 2010Reply With QuoteReport This Post
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Your Bio has lots of Soap in it and or mono/di-glycerides. Basically, the wood chips are not a miracle cleaner and do not simply remove all the soap - regardless of how much soap you start with. They will reduce the soap by a lot but the issue is you got a big variable in there which is how much soap is in the bio to begin with. If you are not measuring soap levels before dry wash and after, there is no way to tell how much soap your wood chips are taking out. (actually there is way, but more on that in second.) Even if you are letting your bio settle in a big tank and it is multiple batches, soap levels will be different in each batch and if you are using KOH, you could have upwards of 1800ppm of soap with all the the Methanol removed. Even if you let demethed bio settle for at least two weeks, you could still be pushing 1200ppm if you used KOH.



I have a little data on Shake'em tests and Soap PPM. I went through a lot of .01M HCL solution (store bought) and Bromo Blue to come up with these numbers.

1) Shake'em tests over 1000ppm using KOH emulsify badly. That is with a vigorous shake, you get one cream layer that really doesn't want to separate. (you might even get a thin layer of bio and water but just barely.) Give it enough time (like 24 hours) and you will get some more separation perhaps even fully, but there will still a lot of emulsion.

2) Shak'em tests about 1000ppm using KOH will emulsify, but will separate on their own in about 20 minutes. You won't like the results as there will still be a lot of emulsion, cloudy bio and cloudy water and scum between the layers, but you will separate in 70 degree weather within a half hour.

3) From About 1000 to about 700ppm using KOH, you will get the orange juice that will more or less quickly separate but again, you wont be happy with the results.

4) From about 550-700, orange juice that will separate even faster, but still not very good. If you let this sit for a long time - like at least 2-3 days, the cloudy water will be more clear as the soap seems to get trapped in the thinner emulsion layer.


Also I think the Wood Chips are not just filtering the soap out. They are acting like the ion resin and converting the soaps to FFA's. Thus now you have more FFA's in your bio which I think forms that extra scum between layers. This is a bit of a conjecture so don't quote me on this last part.
 
Location: Los Angeles | Registered: March 25, 2008Reply With QuoteReport This Post
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I dont see how this works. What if the fuel is demethed before the chips? From what I have seen the more methanol in the fuel the shorter the life of the chips.


Yes. If the fuel is demethed then the sawdust can act as a purely mechanical filter with a large surface area to remove the now suspended soap. If not demethed it removes the meth to make the dissolved soaps suspended. More meth will saturate the ability to remove meth sooner. Drying out will restore some capacity but washing out the soap or replacement will eventually be needed. Your question is actually agreeing with the mechanism I believe I have observed.


mathematical elegance -- desired result achieved with minimal complication
 
Location: Manchester UK | Registered: June 03, 2003Reply With QuoteReport This Post
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Also I think the Wood Chips are not just filtering the soap out. They are acting like the ion resin and converting the soaps to FFA's. Thus now you have more FFA's in your bio which I think forms that extra scum between layers. This is a bit of a conjecture so don't quote me on this last part.


Thanks for those correlations on soap level and observed results in a shake test Doug.

I have heard the theory that tannins are splitting soap into FFA before and having considered it I no longer believe it. I have split soaps into FFAs and it produces a distinctive dark cola coloured fluid. I see no signs of this change of colour in sawdust filtered bio. Tannins were only ever a stab in the dark while people were flailing around for possibilities. Having observed methanol removal at work and being familiar with GL's one day process, where methanol removal is used to preciptate the dissolved soaps into suspension, I see no reason to assume extra mechanisms unless there is evidence for them. Occams razor suggest that we "do not multiply entities needlessly"; or as it is often interpreted "the simplest explantion is the best one".

The extra scum layer between layers is probably resin from the wood it does collect above the water and below the bio in a shake test.

A simple pass or fail test for soap, I use, is to heat a sample in the microwave, to drive off all the meth, then centrifuge it to see what settles out. I can judge if this is going to be a problem with my fuel filter which is the only reason I care about soap content.


mathematical elegance -- desired result achieved with minimal complication
 
Location: Manchester UK | Registered: June 03, 2003Reply With QuoteReport This Post



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I should perhaps add that nuking a sample and spinning it is also how I judge how well the sawdust is currently working on each pass. If a pass through does not remove a significant amount of soap then I repack with new sawdust. When I repack I leave several inches of the previous sawdust in the bottom; this helps keep the fines from coming through from the new pack.

Working with high titrating oil I sometimes need three or four gravity feed throughs to end up with negligable soap levels. Enough passes with good sawdust will eliminate methanol and soap.

Any soap test would do just as well. The shake test is good, as is the soap titration. I just like the combination of ease and quantified result of the nuke and spin; I can see how much, if any, soap might fall out later if the bio sits long enough in my fuel tank or in storage. I am planning to add a second 200lt filter to the system. Still pondering a lead lag or parrallel set up.
Might eventuall go to four drums total to do both.


mathematical elegance -- desired result achieved with minimal complication
 
Location: Manchester UK | Registered: June 03, 2003Reply With QuoteReport This Post
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I am using one of the RolfQuo wood chip drums followed by lead/lag Purolite PD206 resin tanks. Final filter is with a CAT 2 micron fuel filter can.I am happy with the set up.



** Biodiesel Glycerine Soap - The Guide
- on 5 continents helping people make & sell soap from the Biodiesel Glycerine.


 
Location: :-) Great White North eh ? | Registered: December 10, 2004Reply With QuoteReport This Post
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Basically, the wood chips are not a miracle cleaner and do not simply remove all the soap - regardless of how much soap you start with. They will reduce the soap by a lot but the issue is you got a big variable in there which is how much soap is in the bio to begin with.


The University of Idaho did some testing and found that under certain conditions, it did remove all the measurable soap.

Look in the appendix of this link.

Rick
 
Location: Cowboy Country | Registered: December 06, 2004Reply With QuoteReport This Post
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Thanks for everybodies input here. I'm using chips and find them excellent. I'm wondering how often people change them out. 100 gallons? 1000 gallons? 10,000 gallons?

I use 2 - 15 gallon carboys stacked. I just changed the chips after about 1000 gallons. The first time I washed with meth and found lots of it evaporating off the top of the fuel for a batch or two. This time I just used straight dry chips w/out washing them, but I ran finished fuel through them for a day first. I'll be testing before and after batches today....... so I may answer my own question later today. Still I'm interested in what everybody else is doing.
 
Location: SE Ma  | Registered: November 06, 2009Reply With QuoteReport This Post
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The University of Idaho did some testing and found that under certain conditions, it did remove all the measurable soap.


RolfQuo's goes to zero ppm in one pass if it starts out at 1,000ppm or lower. 3,000ppm requires either a slower flow rate or a couple passes. At 800ppm they can open the flow up to maximum.

7 arrows; read the interview with RolfQuo (linked in my sig line). They were up to several k's and still pumping strong at the time of writting.

I know I keep harping on that intyerview, but it's a good one and answers many of the questions concerning the use of hard wood chips as a biodiesel purifier. They do it commercially, and test several times along the way for quality control. Andy is a stickler for quality.



** Biodiesel Glycerine Soap - The Guide
- on 5 continents helping people make & sell soap from the Biodiesel Glycerine.


 
Location: :-) Great White North eh ? | Registered: December 10, 2004Reply With QuoteReport This Post
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That article looks great. My real point is that if you are having problems, looking for the 'odd' thing that is going wrong (resin for example) is a little misleading. You have too much soap in the bio for the wood chips to handle OR the flow rate through the wood chips is too fast. The issuse with saying wood chips are a perfect filter is that there are so many variables - wood chip size, quality, type of wood, flow rate, effectiveness of the ones you got - so there is no standard for measuring wood chip effectivness. The answer I am suggesting is to measure the soap before and after filtering and then determine how you are doing. Also post the data. Remember wood chip filtering is 'cutting edge' and if you are doing it, you are a pioneer in the field.

Doug
 
Location: Los Angeles | Registered: March 25, 2008Reply With QuoteReport This Post



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Originally posted by wal1809:
Salt column


I have not heard of a salt column...........please explain Smile
 
Location: UK | Registered: May 04, 2010Reply With QuoteReport This Post
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Hi Jehu,

what do you do with your methanol-laden glycerine?
 
Registered: July 07, 2008Reply With QuoteReport This Post
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Hi folks,

I'm getting real good soap tests -- 160 PPM after chips. My PH is about 5.8. Is that cool or should I try to get that up to 7-ish?
 
Location: SE Ma  | Registered: November 06, 2009Reply With QuoteReport This Post
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Couple things about that soap test. I had the opportunity to meet with Daniel from Springboard (the guy who devised the test) and we got to talking. He seems to have refined the test. This refinement is not in the video. Also, we discussed a calculation that might have been in error and he agreed.

1) First, use 12ml of Bio, not 10ml. The math for the soap test is based on weight not volume. What is needed for the test is 10grams of Bio, not 10ml. Daniel's original assumption was that 1g=1ml. Its close, but since we are measuring for accuracy down to a few hundred PPM, might as well get it right. 10g of Bio is 12ml and that extra 2ml is a 20% difference, not an insignificant amount.

2) Bromo Blue is odd in that its a tri-color indicator. It changes from Blue to greenish at a ph of 4.6, keeps getting closer to yellow and then changes again to a bright yellow at 3.0. I asked Daniel where exactly do the soaps stop existing. At at ph of 4.6? At 3.0? I mean if you wait till 3.0 (bright yellow) it will require quite a bit more .01HCL then to pass 4.6. He indicated that 4.6 will do. So, the adjustment he made (not in the video) is only watch for the change from Blue to Green. To do so, you really need to accurately blank the solution using .01 HCL and your BASE titration solution (NaOH or KOH). Basically, after adding the bromo blue, drop in the .01HCL till the solution just turns green (or perhaps yellow). Now using small drops, drop in probably 1 drop of BASE Titration solution to make it go blue again. To test again, drop in ONE drop of .01HCL, it should go green again maybe even yellow. Then use 1 drop of BASE Titration solution to make it blue again. At this point you know you are are the teetering point of a ph of 4.6. Add your 12ml of Bio (you can weigh it like I did on a scale as you add it, but 12ml is very very close to 10g). From there, add you .01HCL till it just turns green. No need to go to bright yellow. Then count the ml of .01HCL and multiple 320 or 304. Also, don't forget to stir while you add the .01HCL. It makes a big impact. If you are doing it manually, stop adding and stir before adding more drops.

Doug

This message has been edited. Last edited by: Doug Weiner,
 
Location: Los Angeles | Registered: March 25, 2008Reply With QuoteReport This Post
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I read somewhere a few pages back about someone's woodchips catching fire?
Well, it happened to me yesterday. Eek went out to my shed about 11:30AM and there was smoke coming outof it. Not much but when I opened the door it was full of smoke. the wood chips was on fire and by the looks of the remaining chips, it must of been lit for quite some time. I got REALLY Lucky that all I ended up with is the soot from the smoke on the inside roof of the shed and a melted piece of PVC pipe. it should of or reather should of been alot worse. Just a warning to everyone else. I need to re-think how I use my wood chips since in south Florida, it get HOT. it was about 100 degrees in the shed not related to the smoke. the only option I can think of is to leave the wood chips full of Bio and only drain when the new batch is ready to be put in so that the chips are always in bio and not left to dry...

Now time to clean my pants Big Grin


Danny


05 CRD and 07 Dodge 2500. Both on B100
 
Location: Fort Myers, Florida | Registered: November 30, 2005Reply With QuoteReport This Post
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Hmmmmmmmmmm, spontaneous combustion in bio soaked wood chips, that is pretty scary.
 
Location: West Michigan | Registered: April 26, 2006Reply With QuoteReport This Post



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My 200L drum is always full, but sealed to the air. I think the only part of my system that isn't sealed is the preheat tank, and the final filtering outlet.



** Biodiesel Glycerine Soap - The Guide
- on 5 continents helping people make & sell soap from the Biodiesel Glycerine.


 
Location: :-) Great White North eh ? | Registered: December 10, 2004Reply With QuoteReport This Post
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Glad you caught it.

Please note, the problem really isn't the bio. Its the excess methanol trapped in the wood chips, especially those chips in the middle. Now you got two pretty flammable materials mixed together - wood chips (remember the finer they are, the lower temperature they will ignite at) and the Meth. Add continuous heat and as you have proven, they smolder. Let them go long enough, they find enough oxygen and you got a good fire going.

The Solution?
BUBBLE OFF as much methanol before running them through the chips. Depending on how you bubble, it could two days. I tested a small aquarium bubbler with a small hose with lots of holes poked in it. I started with over .4% and after two days, I still had .06% methanol. So... it takes time.

Thanks for your post and warning to others and I am glad nothing got out of hand.

Doug
 
Location: Los Angeles | Registered: March 25, 2008Reply With QuoteReport This Post
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