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cloudiness after demeth
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Hello, I have been a long time reader and would like to thank everyone here for the help and time they give.

Here is a little information on how I am doing my process. The fuel settles for 3 days, and then is filtered pulling from the top. I run through dry kiln oak sawdust and then through thermax t-45, and then through a 5 micron filter.

At this point the fuel is beautiful and crystal clear. I then run through a vacumn distillation unit to remove methanol.

Now here is my question. The longer I run the fuel through the distillation unit the cloudier it gets. (it is a looped system) I do notice that once the fuel starts clouding I will have just a very tiny amount of soap fallout in a sample jar.

Can anyone please help me to understand what is going on here?

Thank You!
 
Registered: January 22, 2010Reply With QuoteReport This Post
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You need to de-meth before you de-soap.
 
Location: Western NY | Registered: September 16, 2005Reply With QuoteReport This Post
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I thought the thermax needed some methanol left in the fuel to work correctly. Am I mistaken?

BTW the fuels soap level were in the 120ppm range, which is a little higher than I normally like to see. I also noticed this morning that the samples I pulled are starting to clear.

Thanks
 
Registered: January 22, 2010Reply With QuoteReport This Post
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I dont know anything about thermax but I would be demething before letting it settle for 3 days. That will allow the great majority of soap and glycerin to settle out thus adding longevity to the life of your shavings.
Letting it settle for 3 days with the methanol present will only allow glycerin to settle as the soap will still be in solution.
Cheers,
Jon
 
Location: Wellington County, Ontario Canada | Registered: February 07, 2008Reply With QuoteReport This Post
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Thermax doesn't need methanol to work. You have that confused with the gel type resins. I demeth prior to running the biodiesel through the wood shavings and Thermax. If you demeth, the soap will drop out of solution which will make it much easier to remove it from the biodiesel.

At this point you probably could run your biodiesel back through the shavings and Thermax and then test it.

In the future demeth prior to settling. If you don't demeth, you will decrease the usefulness of the Thermax significantly. You will have to flush your columns out with methanol more frequently to remove the soaps which is a bit of a pain.
 
Location: Chambodia | Registered: December 31, 2007Reply With QuoteReport This Post
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Demeth the biodiesel first as suggested. The use of NaOH in the reaction makes soap drop out easier than using KOH. This was brough out by Graham Laming who first introduced the process some time ago.
The whole idea is to remove the methanol so the soap molecules no longer have anything to hold onto and then naturally drop out of solution given a little time.

My method does about what has been suggested; demeth, settle for 2-3 days and then run it through the resin and then a 2 micron can to final polish.



** 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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Thanks everyone!

I reread my first post and I guess I should have given a litle more info. I have been demthing in the reactor after draining glycerine. Problem is I cant reach a high enough pot temp to achieve a high enough reflux column temp. I do recover methanol, but cant get enough removed to pass astm flashpoint.

Since I was thinking mistakenly that the thermax needed a little meth I was testing the distillation unit at the end of the system to "final polish" (has a 5 micron filter in the loop) and "final polish methanol".

The samples I pulled at various times during the looping are crystal clear this morning but the last 3 sample pulled have soap settled in the bottom. I am suprised at how much soap dropout at 120ppm levels, interesting. I am going to send a few of the samples with my buddy to test flashpoint, for curiousity sake.

Definately going to remove all methanol before filtering now that you guys have got me straightened out.

Legal you have me thinking since I am AE'n I could try noah again....wonder how much a difference it actually makes on soap fallout?
 
Registered: January 22, 2010Reply With QuoteReport This Post
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quote:
I cant reach a high enough pot temp to achieve a high enough reflux column temp. I do recover methanol, but cant get enough removed to pass astm flashpoint.


If your reactor is a hot water heater, you will pretty much have to bypass the thermostat to attain a high enough temperature to demeth the BD. Now this is dangerous unless you have a PID controller to turn the heat on and off for you. You could stay with the reactor and monitor the process until the BD is demethed, but the least little diversion and you could have a major problem on your hands.

quote:
Legal you have me thinking since I am AE'n I could try noah again....wonder how much a difference it actually makes on soap fallout?


The soap drops out much faster with NaOH. IMO the only way to go.
 
Location: Chambodia | Registered: December 31, 2007Reply With QuoteReport This Post
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Hrmmm.....soap fall out fast enough to settle one day instead of 3?
 
Registered: January 22, 2010Reply With QuoteReport This Post
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