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Glycerol after methanol recovery, at what point safe for soap?
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Hi Gang. This was originally posted by csp97 over at the methanol recovery forum. I am concerned that we are not getting the methanol out of our glycerol before we make soap. What temp do you bring your glycerol to before making soap? I take my methanol recovery still up to 212 F, but according to the chart below, we might still have 15% methanol or higher at this point.

At what temperature does all of the methanol leave? I sampled some condensate leaving my condensor the other day after the pot had reached 212 F, and there was apparently still some methanol coming out with the water vapor.

Legal and others, I feel that the burden of proof is on us (the soap producers) to guarantee that our soap that came from a formerly toxic byproduct is no longer toxic. Can anyone state with conviction that the glycerol is safe for human washing? Is there anything we can do to react the remaining methanol so that it becomes inert or beneficial?

Thanks for your feedback. Here is the quote from CSP97 that tripped me up, thanks to GL for linking this gem on his website:

quote:

Posted 12 October 2006 05:47 PM
As part of my chem-eng day job, I’ve got access to a chemical process simulator (Hysys). I’ve been looking at adding methanol recovery to my processor, and was using the simulator to calculate the boiling points of various concentration of the methanol with both biodiesel and glycerine. Pure methanol boils at 148F, but as a solution the boiling point will be higher. Thought I’d post it on here as it varies quite a bit with the temperatures that people seem to use in methanol recovery. Any ideas why? The agitation or spraying maybe?

I used 100% m-linoleate for the biodiesel composition. I believe this ester is the main constituent of soybean oil based biodiesel. The calculations are done at 14.696 psia using Antoine.

Biodiesel / Methanol Solution
% MeOH--- Boiling Point, F
5.00 ---------- 209
4.00 ---------- 219
3.00 ---------- 232
2.00 ---------- 254
1.00 ---------- 298
0.50 ---------- 351
0.25 ---------- 411
0.00 ---------- 532

Glycerol / Methanol Solution
% MeOH --- Boiling Point, F
45.00 --------- 172
40.00 --------- 177
35.00 --------- 182
30.00 --------- 189
25.00 --------- 197
20.00 --------- 207
15.00 --------- 222
10.00 --------- 244
5.00 ---------- 288
1.00 ---------- 416
0.00 ---------- 550
 
Location: Chambersburg, PA | Registered: January 01, 2001Reply With QuoteReport This Post
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I will concede two points:

1. I have used home made biodiesel glycerine soap for a few years and have not died or lost my skin. However, before I can feel right about distributing this stuff to a larger group (like little kids and somebody's grandma) I need to know for certain that it is OK and will not cause long term probs

2. I think the info in the theoretical chart might be off. In my experience, I get methanol boiling out of glycerol and biodiesel at much lower temperatures than the chart would indicate for the given percentages.

Anyway thanks for your feedback,
Farmer Roll Eyes
 
Location: Chambersburg, PA | Registered: January 01, 2001Reply With QuoteReport This Post
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Does it need to reach the boiling point for the methanol to leave the glycerin? I thought the boiling point was the maximum temperature it can exist as a liquid before it is forced to change into a gas. If you heat water to 200°F it will not boil but it will "steam up" and evaporate, and the vapor can be condensed back into a liquid.

Ken
 
Location: Sellersville, PA | Registered: May 17, 2006Reply With QuoteReport This Post
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Thanks guys... I appreciate the discussion.

quote:
heat it in a saucepan until it gets to the evaporation temp for methanol (148.5F/64.7C) and then go beyond that a bit.


Legal are we sure that some of the "more tightly bonded" methanol is not still in there? For example, after methanol recovery, my glycerol will not boil or bubble at 148.5 F, but it will boil and bubble at 190 F or thereabouts.... I take this to mean that I still have some methanol in there.

Also it is hard to air out the liquid soap during the curing phase, no?

I will take this up with the chemists on campus.

Thanks for disucssing!
Farmer
 
Location: Chambersburg, PA | Registered: January 01, 2001Reply With QuoteReport This Post
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quote:
Originally posted by farmer:
For example, after methanol recovery, my glycerol will not boil or bubble at 148.5 F, but it will boil and bubble at 190 F or thereabouts.... I take this to mean that I still have some methanol in there.

The stuff that is boiling and bubbling at 190F could be water. You are getting to the point where water will be bubbling quite a bit.
 
Location: East Yorkshire | Registered: January 14, 2006Reply With QuoteReport This Post
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Hi Fuzznag, thanks for your comment.

Just out of curiosity, I took a sample of the distillate coming out of condensor AFTER the pot temp had reached 212F, figuring this should all be water. My very crude density assesment (weighing a liter sample) showed that it was lighter than water, thus theoretically contaminated with methanol. I will try this again on our next round of distillation and post back here.

Cheers,
Farmer
 
Location: Chambersburg, PA | Registered: January 01, 2001Reply With QuoteReport This Post



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Hi Gang,

We just got the results back from our glycerol testing at the PA Department of Environmental Protection:

AFTER going through methanol recovery to 190F or higher, our glycerol had a flash point of 39.5C (about 89 F) and contained about 8% methanol. According to the DEP, this is still classified as a hazardous material due to the low flash point.

This is troubling news for soap production unless we can get some chemist to tell us why glycerol with 8% methanol should be considered safe for use as soap.

Any thoughts?

We are going to re-run the methanol tests after paying a little closer attention to the variables in our methanol recovery process. The batch I gave the DEP came out of a bulk barrel where we store our GLY after recovery, but I am not sure if it was recovered to 190 F or to 212 F, which is our normal shop practice.

Stay tuned!
Farmer
 
Location: Chambersburg, PA | Registered: January 01, 2001Reply With QuoteReport This Post
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Nice topic farmer.

I thought the same thing about meth still being in the glyc,so we heat ours to 300-350 to get what we feel is good enough.
- it surely does not ignite but there are still trace amounts of meth in it.
-Those that only go in the 1?? range are not even getting close to having demethed Glyc.


Chad
2000 F350 SD 7.3PSD, 1996 F250 SD 7.3 PSD, 2005 Jeep liberty CRD, 2002 TC29D New Holland Tractor, 6K Diesel Generator, Heated Power Washer 'All Burnin Bio'

http://arborbiofuelscompany.com/ Selling Dry Wash Columns.

http://i88.photobucket.com/alb...icationGCresults.jpg
 
Location: S.E Michigan | Registered: May 12, 2007Reply With QuoteReport This Post
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I've been concerned about that too... What is an acceptable amount of methanol to be in the glycerin?

Like Chad we hit 300*F-350*F... But according to the chart it's not gone until 500*F.

I also believe we should also capture the distillate during the full process of de-mething. Which means our purity will go down because we will also in some cases be distilling water.

We might have to adopt a 2X distillation process for our methanol like they use for ethanol. I believe that it is called beer stripping. They remove all distillates and then redistill the captured distillate and separate those based on the head temperature. Not a difficult thing for us to do either, we would just have to add some water as to not expose our heating elements once we have all the methanol re-captured). With a proper fractionating column we should actually be able to increase our purity with the 2X distillation. The left over water could then just be disposed of even if there is still a bit of methanol left in it. I understand that disposing liquid methanol is not a "bad" thing. But evaporating it with distillation into the air is.

Just some food for thought...


-Rick

http://www.knicenclean.com your single-most largest free BDG soaping content on the internet.
SAP Testing, Ingredient Properties, Soap Glossary and Recipes just to name a few.

Making Biodiesel Byproduct Soap Learn how to use your biodiesel byproducts to make great bar and liquid soap!!!

"Closing the loop on biodiesel production one bar at a time!"

Beware of the Dunning–Kruger effect.
 
Location: S.E. Michigan | Registered: April 15, 2007Reply With QuoteReport This Post
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I've just come across an interesting article. The link is below, and you have to pay to view it. The article talks about making soap in a process of using methyl-esters as a way of removing the glycerin. I'm going to read it in full tonight. Interesting that one of the industry practices for soap making would be sort of making BD and turning it into soap. They take the glycerol and sell it.
We've tried making soap from BD... Yucky stuff...

I'll let y'all know what I find out.

http://www.springerlink.com/content/2274013752u26uw8/


-Rick

http://www.knicenclean.com your single-most largest free BDG soaping content on the internet.
SAP Testing, Ingredient Properties, Soap Glossary and Recipes just to name a few.

Making Biodiesel Byproduct Soap Learn how to use your biodiesel byproducts to make great bar and liquid soap!!!

"Closing the loop on biodiesel production one bar at a time!"

Beware of the Dunning–Kruger effect.
 
Location: S.E. Michigan | Registered: April 15, 2007Reply With QuoteReport This Post
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Thanks Guys for your comments, and Legal for your testimony from experience. We too are using the soap and have no ill effects, but we're going to try to get third party verification before we sell soap to the public. Too many liability concerns in todays legal climate!

quote:
I also believe we should also capture the distillate during the full process of de-mething. Which means our purity will go down because we will also in some cases be distilling water.


Our addition of a reflux column seems promising... a recent batch stopped at 260F, and methanol was still coming out at 95% pure.

More soon!
farmer
 
Location: Chambersburg, PA | Registered: January 01, 2001Reply With QuoteReport This Post
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HI gang,

We had some of our glycerol tested for flash point...

We pulled samples from a recovery batch, watching the pot temp. Here are the sample temps and flash point test results...

sample run at 240, flashpoint 143.6F/ 62C
sample run at 250, flashpoint 140F/ 60C
sample run at 260, flashpoint 208F/ 98C

The breaking point for Haz Mat status is 140F. So we are taking our glycerol recovery to 260 F to be sure we get above that mark...

Not sure if the methanol percentage is low enough to be safe for soap, we are still working on that question.

The drag of course is that it takes a long time to get to 260 F, and the high temps give me the willies. Am thinking about trying vacuum distillation just to make it safer...

Stay tuned!
Farmer
 
Location: Chambersburg, PA | Registered: January 01, 2001Reply With QuoteReport This Post



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Vacuum with heat certainly reduces your heat/energy input.

Remember that if you're using a thermostat on your heater that you *could* use a lot of heat in vain.

When you have a change of state (ie boiling), the liquid will remain at the same temp until that material is removed, regardless of heat input. Think about boiling water- it stays at 212F until it boils off, even if you turn up the heat.

A suggestion is to do your heat/vacuum calculation and set your thermostat there. Wait for your liquid to get to that temp, then draw the vacuum.

If your vacuum cannot increase due to change of state, that's fine. It uses much less electricity than the heating element Smile

Also be sure to use a trap between your vacuum pump and the distillation device (I use a refrigerant recovery tank). It should have a diptube, which goes to the tank side and a separate valve that goes to the vacuum pump.

Also keep in mind that you should introduce some air into the bottom of your vessel when vacuum/boiling off the methanol.

I wait for it to get to temp and vacuum that I want, then allow a slow "leak" of air in my bottom drain valve. Just a gentle bump/boil is good- not too violent, but not just a slow glug (sorry for the complex technical terms Smile )

Hope this helps.

- JC
 
Location: Western PA | Registered: August 15, 2008Reply With QuoteReport This Post
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Hi Gang,

Has anyone brought an appleseed up to these temps (240-260)?

I have one with a jet pump (venturi) from mcmaster pulling a draft on a plumbers delight condenser. The plumbing is all cast iron on my processor but I use the standard clear water pump from harbor freight.

I have accumulated enough glyc at this point to attempt methanol recovery from the glyc with the intention of making soap. I am concerned about equipment failure (pump and/or water heater tank) at these very high temps. any thoughts? Thanks for your help.
 
Location: Long Island, NY | Registered: May 31, 2008Reply With QuoteReport This Post
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I was out to see Farmers setup on Friday, they use an appleseed with the infamous blue pump for methanol recovery. I plan on using a circ pump for a heater which is rated to 230F, I feel better that way.



 
Registered: April 28, 2008Reply With QuoteReport This Post
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Thanks Guys. I havent taken the appleseed over 200F yet so I was a little concerned.

I have a Grundfos pump sitting in a box on standby so maybe I will err on the side of caution and swap out the HF pump just to be safe.

Legal, This will be my first pass at soapmaking. I bought your gude a while back so I'll let you know how I make out. I process with KOH and will try liquid soap on my first attempt. Do you recommend adding the water and the additional KOH to the processor or using the processor for heating/demethaliting and drawing off the heated/demethalated glyc into a bucket and then adding the water/KOH solution?
 
Location: Long Island, NY | Registered: May 31, 2008Reply With QuoteReport This Post
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Newbie,

quote:
Has anyone brought an appleseed up to these temps (240-260)?


I typically run my Meth Recovery up to 250F. About 40% of the time, I get boil over though. I'm trying to squeeze as much methanol out as possible. I too, have a venturi. It's a Mazzei. It's rated for 200F, but I contacted the mfgr and had them send me a spec sheet. The engineer said that it had to do with the plastic melt and deformation point AS WELL AS the material that was going through the injector. I was also referred to a site that gave me a few numbers that I could plot. I then put a dot on the plot where my 20 psi back pressure was at 250F and realized that I'm well under the yield point.

I have to admit, the first couple of times over 200F, I was sweating it. Now that I've been to 250 a few times and I've crunched the math, I'm no longer concerned.

FYI, you'll want to monitor how much vapor you run through the venturi. The more you run, the harder it is to do fractional distillation against the material going through the standpipe.

Are you set up to do fractional?

If you're going to reuse the methanol (why not, it's not cheap), you'll want to monitor the head temp, else you'll get crappy purity (less than 95%)

FYI, I've run 19 meth recoveries since Feb, which was my first MR.

- Steve


2007 Dodge Ram, 2x-2006 VW Jettas - 34,000 B100 miles by 2009.
 
Location: Bay Area, California | Registered: October 05, 2007Reply With QuoteReport This Post
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Freesoul,

quote:
Posted 05 October 2008 09:31 PM Hide Post
I was out to see Farmers setup on Friday, they use an appleseed with the infamous blue pump for methanol recovery.


I've been using the same blue pump. I must admit, these things 'take a lickin and keep on tickin'. I've done 19 Meth Recoveries all to 250f and it isn't even whining yet. I'm on my 99th batch of bio this year on another one of those blue pumps. Some batches I've processed for 8+ hours. It's still running. I've timed the flow rate....11-12gpm at processing temp (140F)

You can't beat the price.

Advice: Use them for everything, use unions on both sides and keep a spare. I haven't needed it yet, but when I do, it will be a snap to replace.

- Steve


2007 Dodge Ram, 2x-2006 VW Jettas - 34,000 B100 miles by 2009.
 
Location: Bay Area, California | Registered: October 05, 2007Reply With QuoteReport This Post



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quote:
fractional distillation

Im not setup for fractional and I suspect that I am pulling way too much draft making the distilation process less efficient than it cound be. I am experimenting with valve settings on the pump output in an attempt to slow the liquid as it passes the venturi and hopefully reduce he draft on the venturi. This puts strain on the pump though. I would really like to install a bypass to allow a portion of the liquid to go around the venturi which would reduce the flow and the draft.

At the moment I am planning on distilling and then using the distilate in a 10 to 1 ratio with new methanol in subsequent batches. Do you think the water content in the distilate will be a big issue in that ratio? My oil is very dry before processing and I do not use a prewash so I am thinking that the water content should be very low. Thoughts?
 
Location: Long Island, NY | Registered: May 31, 2008Reply With QuoteReport This Post
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quote:
Originally posted by AwesomeNet:
Freesoul,

quote:
Posted 05 October 2008 09:31 PM Hide Post
I was out to see Farmers setup on Friday, they use an appleseed with the infamous blue pump for methanol recovery.


I've been using the same blue pump. I must admit, these things 'take a lickin and keep on tickin'. I've done 19 Meth Recoveries all to 250f and it isn't even whining yet. I'm on my 99th batch of bio this year on another one of those blue pumps. Some batches I've processed for 8+ hours. It's still running. I've timed the flow rate....11-12gpm at processing temp (140F)

You can't beat the price.

Advice: Use them for everything, use unions on both sides and keep a spare. I haven't needed it yet, but when I do, it will be a snap to replace.

- Steve


Steve, I'm not disputing the performance, just the safety. I wouldnt want to be around when it fails while pumping methanol laden glycerine at 200+ degrees.......



 
Registered: April 28, 2008Reply With QuoteReport This Post
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