BIODIESEL & SVO DISCUSSION FORUMS





Sponsors    Biodiesel and SVO Forums Home    Forums  Hop To Forum Categories  Biodiesel  Hop To Forums  Methanol Recovery    GL's process and glycerine methanol
Page 1 2 

Moderators: Shaun, The Trouts
Go
New
Find
Notify
Tools
Reply
  
GL's process and glycerine methanol
 Login/Join
 
member
posted
I'm sure this is in the big GL thread somewhere, which I still havne't had the heart to wade through, but what's the 'short answer' on whether you can evaporate methanol out of glycerine using the GL Eco-System processor?
 
Location: Pittsboro, North Carolina | Registered: March 07, 2001Reply With QuoteReport This Post
Member
posted Hide Post
I can't remember it being done with the GL process. Seems like I read somewhere that it was not feasible for some reason.

Sorry but I cannot be more specific than that but hope it helps.

Larry
 
Location: Oklahoma | Registered: July 18, 2006Reply With QuoteReport This Post
Member
posted Hide Post
Girl Mark,
My understanding is that the glycerol byproduct foams up a great deal and as the meth is removed, the glycerine gets thicker...making it more difficult to pump and use a venturi for aeration. Also, demething glycerine thoroughly may require much higher temperatures. The "stil" used should be a reflux type to improve meth purity as the 5% prewash water is mostly in the byproduct.
 
Location: Virginia, USA | Registered: August 05, 2007Reply With QuoteReport This Post
member
posted Hide Post
Mark,

I have 0 experience with GL, but recall reading that he is in the process of showing that the BD and glycerine layer can be distilled at the same time without a serious reverse reaction. At least that was the preliminary result, as I recall.

So, he is distilling the glyceine layer in his processor.


Andrew

http://biodieselcommunity.org
03 Dodge 2500 B100 homebrew
79 Rabbit B100 homebrew
 
Location: Northern California | Registered: February 27, 2006Reply With QuoteReport This Post
member
2013 Sponsor
posted Hide Post
Mark,

I've tried it and it works, at least with low titration oil. I still have some unanswered questions and no time to find my own answers. I've got other priorities taking up processor time.

Increased headspace means more cold metal to condense the methanol back into the bio before it reaches the condenser.

The more insulation you have the less condensation you get of the exposed metal surfaces, see above.

I got very little flow until the temp reached 180F or so.
 
Location: Cowboy Country | Registered: December 06, 2004Reply With QuoteReport This Post
Member
posted Hide Post
Hi GM

Graham reports the gylcerine phase becomes very viscous when recovering the methanol from the whole batch and suggests a gear pump would be better than the perpheral/centrifugal types most of us use. He also address the issue of the reverse reaction by dosing with HCl to neutralise the catalyst. Personally, I do the 5% prewash but I don't attempt to remove all the methanol from the whole batch so that the byproduct layer does not solidify and the recoverd methanol is reasonably pure.

Nick


Free collection of waste cooking oil in the Nottingahm area http://wastevegoil.co.uk
 
Location: Nottingham UK | Registered: December 14, 2005Reply With QuoteReport This Post



Member
posted Hide Post
Hi GM

As Nick mentioned, the viscosity rises dramatically as methanol concentration in the glycerol drops, so the venturi fails to operate if using glycerol alone..

So here's an interesting twist, which works well, I have had no issues with back reaction as far as I can tell, and no problems with foaming....

After reaction, keep the pump running and do NOT drain the glycerol, and do NOT do 5% prewash,.

Instead, add a 1/2 teaspoon of phenolphthalein powder per 100 litres batch and allow to mix thoroughly. You'll need a sight tube to view the mixture. A narrow clear branched tube, off the outlet of the pump is safest - you want to be able to instantly see the colour change, so the tube must carry some of the pump outlet flow thru it.

Very slowly (I mean VERY SLOWLY) dose 34% conc. HCl into the inlet of the pump and note the colour change. When you get to about 0.1% dosed volume, you'll see the deep red will lighten up a bit.

STOP adding HCL at this point.
The colour will darken again in a few minutes, DON'T add any more HCl or you will start to make FFA from the soap. The lye will preferentially neutralise first with the HCL, then the soap.

The NaOH or KOH should mostly be neutralised now, making it an ineffective catalyst for what follows...

Add heat to the whole batch and start distilling off the methanol, you'll need to go up to 90C or more.

When this becomes a trickle, stop.

The glycerol will drop out within a matter of seconds when you stop the pump, drain it before it cools and solidifies.

Then drain off the remaining biodiesel into a settling tank to allow soap to drop out, or you can wash it gently as is - it should wash fairly easily if you treat it gently for the first one.

Key things
1. Use a pump which can deal with the viscosity.
2. Don't OD on HCL.
3. Don't dose HCL too fast, or you'll make FFAs

For a 100 litre batch, you'll use around 100ml HCL, depending on titration, amount of lye, water in oil etc.

My pump is roughly 1/2 batch volume per minute.

Dose the HCL at a rate which will take around 30 minutes to complete, at the inlet of your pump so it mixes well.

This is info to the best of my knowledge to date - there is a lot still to learn and much can be done to improve the process, but it is showing good promise as a simple, fast efficient way to recover methanol from the whole batch and aid washing or eliminate the use of water.

Hi Rick
The biggest drawback with a lot of headpace is it can hold a lot of methanol vapour, regardless of the wall temperature. Ideally you want small headspace, so you can expel most of the methanol from the tank, PLUS good insulation to speed recovery.


Rover 75 + Skoda Fabia on B100
http://www.graham-laming.com

Bicycle on G100 12,000 miles p.a. ( http://uk.virginmoneygiving.com/GrahamLaming )
 
Location: UK | Registered: December 04, 2005Reply With QuoteReport This Post
member
2013 Sponsor
posted Hide Post
OOPS. After reading the thread again I see the question was about evaporating the methanol from the glycerin. I have not tried that.

Viscoscity may not be an issue when using KOH.
 
Location: Cowboy Country | Registered: December 06, 2004Reply With QuoteReport This Post
Member
posted Hide Post
So, the key here is to mention Graham's name enough times in a thread and he will update us with the latest secrets.

LOL

Rich
 
Location: Virginia, USA | Registered: August 05, 2007Reply With QuoteReport This Post
Member
posted Hide Post
quote:
Originally posted by GrahamLaming:
.....add a 1/2 teaspoon of phenolphthalein powder per 100 litres batch and allow to mix thoroughly. You'll need a sight tube to view the mixture. A narrow clear branched tube, off the outlet of the pump is safest - you want to be able to instantly see the colour change, so the tube must carry some of the pump outlet flow thru it.


Hi Graham, List

Phenolphthalein is not cheap, especially if you're using 1/2 teaspoon each batch. Also, it may be carcinogenic and being a powder, there's a possibilty of inhalation. What happens to the indicator? Does it end up in the biodiesel or in the byproduct phase? If it ends up in the bio, are there any potential issues?

I was just wondering what was the advantage of doing a "whole batch" titration over drawing off a small sample at the end of the reaction and titrating that. Also, there is presumably a relationship between the acid number of the oil feedstock (and thus the amount of NaOH added) and the pH of the resulting whole batch (assuming other factors like water content are constant). If there is a direct corrolation, you wouldn't have to titrate at all.

ISTR reading a paper which said that the reverse reaction takes place at a much higher temperature (~200*C) than the transesterification reaction. Is that not the case in practice?

Cheers

Nick


Free collection of waste cooking oil in the Nottingahm area http://wastevegoil.co.uk
 
Location: Nottingham UK | Registered: December 14, 2005Reply With QuoteReport This Post
Member
posted Hide Post
Hi Nick

The amount of HCl needed seems to vary, even for similar titration oils. I think this may be due to water robbing some of the NaOH via soap creation.

Phenolphthalein decomposes to CO2 and water on burning, and it all seems to end up in the glycerol (I tried adding methoxide to the resulting biodiesel to see if it would go pink and it didn't).

I believe it is a carcinogen if ingested in reasonably high volumes, regularly - it was used as a laxative for many years.

The reason I suggest doing a whole batch titration is that I've done it that way with repeated success - but have had difficulty matching results from a sample titration - needs more work to find out why - I suspect I am adding HCl too fast in the beaker and neutralising soaps too. Just needs development of a suitable method, and good sampling so you don't sample glycerol-heavy or glycerol-light biodiesel out of the pipework.

You can make up some stock 'bulk' titrant by dissolving the phenolphthalein in alcohol, which would have less risk of inhalation.

I think reverse reaction happens at lower temperatures too, just slower.


Rover 75 + Skoda Fabia on B100
http://www.graham-laming.com

Bicycle on G100 12,000 miles p.a. ( http://uk.virginmoneygiving.com/GrahamLaming )
 
Location: UK | Registered: December 04, 2005Reply With QuoteReport This Post
Member
posted Hide Post
quote:
The reason I suggest doing a whole batch titration is that I've done it that way with repeated success - but have had difficulty matching results from a sample titration - needs more work to find out why


I wonder if this is because, with our low throughput pumps, the glycerol tends to settle out even with the pump running - if that is true, the pH could vary with depth in the tank?

Nick


Free collection of waste cooking oil in the Nottingahm area http://wastevegoil.co.uk
 
Location: Nottingham UK | Registered: December 14, 2005Reply With QuoteReport This Post



Member
posted Hide Post
Nick,

I think you've hit the nail on the head with that suggestion!

My sample titrations all let me to OD on HCl which suggests there was more than a typical amount of glycerol in the sample.

I costed up my phenolphthalein and even if doing a full batch titration, I'm only adding US$0.01 (a half of our fine British pence) per litre to my cost of production, and recovering all that extra methanol as a benefit.

So it still makes good economic sense, but even better economic sense would be great!

PS - getting some FANTASTIC rapeseed oil now from another source with 1 year renewable signed contract for exclusive claim. I've never had it so good! NO hydrogenated sludge !! Early Christmas for me. AND they drop it off to me!


Rover 75 + Skoda Fabia on B100
http://www.graham-laming.com

Bicycle on G100 12,000 miles p.a. ( http://uk.virginmoneygiving.com/GrahamLaming )
 
Location: UK | Registered: December 04, 2005Reply With QuoteReport This Post
Member
posted Hide Post
quote:
PS - getting some FANTASTIC rapeseed oil now from another source with 1 year renewable signed contract for exclusive claim. I've never had it so good! NO hydrogenated sludge !! Early Christmas for me. AND they drop it off to me!

Early Christmas indeed - nice score Smile Any chance of putting the contract on your shiny new dot.com website?

Nick


Free collection of waste cooking oil in the Nottingahm area http://wastevegoil.co.uk
 
Location: Nottingham UK | Registered: December 14, 2005Reply With QuoteReport This Post
member
posted Hide Post
quote:
Originally posted by girl mark:
. . . 'short answer' on whether you can evaporate methanol out of glycerine using the GL Eco-System processor?



Yes!
 
Location: Illinois | Registered: February 21, 2006Reply With QuoteReport This Post
Member
posted Hide Post
phenolphthalein is nothing more than a laxative which is used in ex-lax. not carcinogenic.


Shawn

2006 F-250 6.0l PSD Crew W/ FS BED Runnin' on Homemade B-100 (NOT!!!) If you have a 6.0 DO NOT RUN B/D unless you have a LOT of money for injectors and fuel pumps and fuel injection control modules and...

This message will self destruct
 
Location: sunny Palm Bch.County, Fl. Home of the "Hanging Chad" | Registered: July 16, 2006Reply With QuoteReport This Post
member
posted Hide Post
quote:
Originally posted by trtmntdude:
phenolphthalein is nothing more than a laxative which is used in ex-lax. not carcinogenic.


http://www.jtbaker.com/msds/englishhtml/p2015.htm

MSDS says it possibly is a carcinogenic.


Regards,
Keith

"The government is not best which secures mere life and property--there is a more valuable thing--manhood."
- Mark Twain's Notebook


2004 GMC Duramax 6.6 LLY now on B100 "Applejuice"
 
Location: Whiteville, NC | Registered: March 11, 2008Reply With QuoteReport This Post
Member
posted Hide Post
no more ex-lax for me! Eek


Shawn

2006 F-250 6.0l PSD Crew W/ FS BED Runnin' on Homemade B-100 (NOT!!!) If you have a 6.0 DO NOT RUN B/D unless you have a LOT of money for injectors and fuel pumps and fuel injection control modules and...

This message will self destruct
 
Location: sunny Palm Bch.County, Fl. Home of the "Hanging Chad" | Registered: July 16, 2006Reply With QuoteReport This Post



member
posted Hide Post
I do recover from glycerin but as a seperate operation. The glycerin does get thick but my pump is still moving it. I also lose some suction through the venturi as it progresses but it seems that the methanol is all out about the time the venturi stops working..coincidence? I use NaOH and hve run this twice with the same resuts, 11.5 gallons of methanol out of 50 gallons of glycerin. If I am not recovering it all it is not by much and the convenience of using one processor for everything outweighs the loss I think.

Tony


2002 Ford Excursion 7.3l
1983 Mercedes 300D
GL processor
You're not finished when you lose,
You're finished when you quit.
 
Location: Tampa, Fl | Registered: April 27, 2007Reply With QuoteReport This Post
Member
posted Hide Post
I have a GL-style processor and I recover the methanol from the glycerol as a separate operation. I store the glycerol from each batch I make in sealed 25L containers and when I have enough I fill the reactor and turn up the heat.

It helps that I use KOH rather than NaOH. I only heat the reactor to approx 80C and this seems to recover sufficient methanol (approx 15L from an 80L batch of glycerol) without the problems of glycerol foaming.

I use some of the hot de-methed glycerol to make a liquid soap which works nicely as well.

David
 
Location: North Yorkshire | Registered: February 09, 2003Reply With QuoteReport This Post
  Powered by Social Strata Page 1 2  
 

Sponsors    Biodiesel and SVO Forums Home    Forums  Hop To Forum Categories  Biodiesel  Hop To Forums  Methanol Recovery    GL's process and glycerine methanol

© Maui Green Energy 2000 - 2014