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demething whole batch (bio and glyc ) NO ACID
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I started demething the whole batch (bio and glyc together) without using any ACID awhile back
http://biodiesel.infopop.cc/ev...449605551/m/97010537

quite a few others have now successfully repeated this and some of us are now doing it as standard.
http://www.vegetableoildiesel....thread.php?tid=11912

I posted about this on the UK forum of infopop but thought I'd open it up to a wider audience now it seems to be working well for a few of us in the UK, give it a try and see what you think.

This message has been edited. Last edited by: Chug,


*************************
1996 Transit Tipper
1991 Mercedes 709D
1994 Citroen ZX 1.9TD engine now in peugeot 306D
*************************
http://www.biofuel-uk.net/

The Collaborative Biodiesel Tutorial
http://www.biodieselcommunity.org

 
Location: S.E. England | Registered: September 05, 2004Reply With QuoteReport This Post
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Are there any numbers on MG and DG pre and post demeth?

Any tests beside shake?

Are shake tests the same pre and post?

This is a great idea. As long as it does not reverse it too much.


Andrew

http://biodieselcommunity.org
03 Dodge 2500 B100 homebrew
79 Rabbit B100 homebrew
 
Location: Northern California | Registered: February 27, 2006Reply With QuoteReport This Post
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quote:
They do this because it significantly decreases the time for the glycerine to settle out.


Yeah, that is great. The question on this idea that has yet to be answered in a definitive way involves the degree to which it causes a reverse reaction. I suppose it will depend on the individual conditions. Any numbers would be helpful, from my POV.


Andrew

http://biodieselcommunity.org
03 Dodge 2500 B100 homebrew
79 Rabbit B100 homebrew
 
Location: Northern California | Registered: February 27, 2006Reply With QuoteReport This Post
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quote:
Originally posted by Andrew M:
quote:
They do this because it significantly decreases the time for the glycerine to settle out.


Yeah, that is great. The question on this idea that has yet to be answered in a definitive way involves the degree to which it causes a reverse reaction. I suppose it will depend on the individual conditions. Any numbers would be helpful, from my POV.


good numbers cost a lot of money..

I guess if your demeth process takes a little time thats when you run into trouble of reverse rxns..

btw what temp and pressure do u demeth at?

This message has been edited. Last edited by: Reece123,
 
Registered: March 02, 2009Reply With QuoteReport This Post
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quote:
good numbers cost a lot of money.


A GC test is around $75 I think, just for FTG and MG DG TG breakdown.

Even a pHlip test would tell us something. $5 per I think.

3/27 will tell you, IMO, next to nothing about a reverse reaction. It will only tell you if you have a REALLY serious one, since it mainly tests TG.

quote:
btw what temp and pressure do u demeth at?


I don't do this process. I don't plan to until I can see data that shows it is not making the fuel much worse.


Andrew

http://biodieselcommunity.org
03 Dodge 2500 B100 homebrew
79 Rabbit B100 homebrew
 
Location: Northern California | Registered: February 27, 2006Reply With QuoteReport This Post
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I'm afraid we can offer no data other than gut feeling from a few experienced brewers, but in some of the first attempts we were not as careful at calculating when to stop demething, and water shake up tests showed traces of mono/di glycerides and possible reverse reaction, since we've been stopping demething when a certain amount is recovered there are no signs of these.
Jim (jamesrl venturi basher) is singing the praises of this method the UK Goat forum tonight.
http://www.vegetableoildiesel....912&page=1#pid128356

We demeth at atmospheric pressure using GL style processors and try to keep the condensor head temp around 65-70°C which usually means bio/glyc batch temp of up to 85-90°C


*************************
1996 Transit Tipper
1991 Mercedes 709D
1994 Citroen ZX 1.9TD engine now in peugeot 306D
*************************
http://www.biofuel-uk.net/

The Collaborative Biodiesel Tutorial
http://www.biodieselcommunity.org

 
Location: S.E. England | Registered: September 05, 2004Reply With QuoteReport This Post



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I'd by interested you your actual pot temps when you stop demethying..

I normally stop methanol recovery from glycerin only at 205F

if this can be done that would be good news to lots of people. myself included


-dkenny


'84 bluebird school bus, DD8.2L turbo( 4/2011, the bus tranny has died..Frown 8.23.11 bus driven to scrap yard Frown )
2006 Jeep Liberty CRD Smile - the wife's
99 dodge 2500 5.9l 24v..-mine Smile
everything run B100 when its warm enough Smile
 
Location: RTP, North Carolina | Registered: December 15, 2004Reply With QuoteReport This Post
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dkenny

We start demething as soon as reaction is finished and the batch of bio/glyc is still around 55-60°C the max batch temp reached towards the end of the demeth to keep still/condensor head around 65-70°C is no more than 90°C which is 194° F in your old money, we don't prewash anymore since adopting this method so it shouldn't matter if you went to higher temps but there really is no need.
When I've had to start with heating a cold batch back up the methanol starts flowing from as low as 40°C batch temp, but the main thing is keeping the still/condensor head around 65-70°C

If you have a GL style processor with venturi for meth recovery try my whole batch demeth method, and if you are worried with all the hype about reverse reaction just try it on a small batch.
We have had no reported problems so far from those that have tried this method just great feedback about saving time/energy reduction.


*************************
1996 Transit Tipper
1991 Mercedes 709D
1994 Citroen ZX 1.9TD engine now in peugeot 306D
*************************
http://www.biofuel-uk.net/

The Collaborative Biodiesel Tutorial
http://www.biodieselcommunity.org

 
Location: S.E. England | Registered: September 05, 2004Reply With QuoteReport This Post
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It would be good if someone with pHlip test kit could try this whole batch demeth and post the results from the test, or even better still if you have GC equipment


*************************
1996 Transit Tipper
1991 Mercedes 709D
1994 Citroen ZX 1.9TD engine now in peugeot 306D
*************************
http://www.biofuel-uk.net/

The Collaborative Biodiesel Tutorial
http://www.biodieselcommunity.org

 
Location: S.E. England | Registered: September 05, 2004Reply With QuoteReport This Post
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Nice one Chug, You tell'm.
I now do a 3/27 before and after demeth, the post test looks far better than anti but I now stop approx. 200ml short of the calculated volume of distilate (12.5% of batch size), or as Chug says Stoichiometric measure, flash git.
The reason I stop short is because I had a slight reveres when I distilled until nothing dripped out.
I do a 50/50 shake test with distilled water, this apparently will show up any glycerides, none been seen yet.
 
Location: Suffolk, UK | Registered: November 08, 2006Reply With QuoteReport This Post
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so to make sure we don't get a reverse reaction..couldn't we just add water..just the 5% prewash?

mix a couple of minutes then start demething?

I might try in the next batch in my water heater reactor.

I know my setup can handle the water during the demething stage. I demeth 5% prewash glycerin all the time.

-dkenny


'84 bluebird school bus, DD8.2L turbo( 4/2011, the bus tranny has died..Frown 8.23.11 bus driven to scrap yard Frown )
2006 Jeep Liberty CRD Smile - the wife's
99 dodge 2500 5.9l 24v..-mine Smile
everything run B100 when its warm enough Smile
 
Location: RTP, North Carolina | Registered: December 15, 2004Reply With QuoteReport This Post
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We no longer pre-wash as the soap settles out superfast with the glyc once demethed, and it really is something to watch, I'm still amazed by the speed of it, and the methanol purity should be better if there is less chance of pre-wash water ending up in it.

This week I got a Tralles scale hydrometer so I'll be accurately checking purity of each recovered batch from now on, the only recovered methanol I've got sitting around to test I know had some water in from another batch but still comes out at just over 93% purity.


*************************
1996 Transit Tipper
1991 Mercedes 709D
1994 Citroen ZX 1.9TD engine now in peugeot 306D
*************************
http://www.biofuel-uk.net/

The Collaborative Biodiesel Tutorial
http://www.biodieselcommunity.org

 
Location: S.E. England | Registered: September 05, 2004Reply With QuoteReport This Post



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I'm getting a steady 97% pure methanol without prewash and no reveres reation that I can tell of.
 
Location: Suffolk, UK | Registered: November 08, 2006Reply With QuoteReport This Post
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quote:
Originally posted by jamesrl:
I'm getting a steady 97% pure methanol without prewash and no reveres reation that I can tell of.


what would you guess the 3% be made up of?
glycerin?
 
Registered: March 02, 2009Reply With QuoteReport This Post
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quote:
Originally posted by Reece123:
quote:
Originally posted by jamesrl:
I'm getting a steady 97% pure methanol without prewash and no reveres reation that I can tell of.


what would you guess the 3% be made up of?
glycerin?


It's probably water. The biodiesel reaction itself produces trace amounts of water.

Finest regards,

troy
 
Location: north america somewhere close to the midwest, or not | Registered: May 29, 2004Reply With QuoteReport This Post
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I am a real rookie at this biodiesel. I currently have constructed a "Murphy's Machines BioDiesel System" from 500 gallon propane tanks. I have had success in making some fairly "clean" bio that I have used in my Cat loader and several of my DuraMax GMC towtrucks. I do end up replacing the fuel filters about twice as much as before.
A couple of questions:
1) How do I determine how much methanol is available for recovery?

2) How do I recover the methanol effeciently?

3) What the devil can I do with all this nasty glycerin?
 
Location: Minneapolis, MN | Registered: May 01, 2009Reply With QuoteReport This Post
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For one, you shouldn't have to keep replacing filters after the first couple tanks of bio. IF there was sediment, sludge from your diesel, it should pass relatively quickly unless it's a really old vehicle.

If you continue getting filter clogging issues, then you fuel probably isn't quite up to spec.

As far as dealing with your byproducts, the solution is going to depend on the scale of your operation, and your location. Methanol recovery is another important question that you touched upon. The amount of recoverable methanol is going to vary based on your production method.

If you feel that these issues need to be address, I am a chemical process engineer specializing in biodiesel. I work with clients either on a discounted retainer, or at an hourly rate.

Take Care!
 
Location: CO, CA, KS, or FL | Registered: January 17, 2009Reply With QuoteReport This Post
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quote:
Originally posted by m1niel:

3) What the devil can I do with all this nasty glycerin?


On this forum there was a topic 100 uses for glycerin or something like that.. if you do a 10 minute google search you will be overwhelmed with possibilities..dust suppressent, soap, fertilizer etc etc
 
Registered: March 02, 2009Reply With QuoteReport This Post



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C'mon guys, surely there must be one or two of you across the pond who are willing to give my whole batch demething a try? even if you only do a small batch because of worry with all the hype about about reverse reaction, those that have tried it in the UK are lovin it!


*************************
1996 Transit Tipper
1991 Mercedes 709D
1994 Citroen ZX 1.9TD engine now in peugeot 306D
*************************
http://www.biofuel-uk.net/

The Collaborative Biodiesel Tutorial
http://www.biodieselcommunity.org

 
Location: S.E. England | Registered: September 05, 2004Reply With QuoteReport This Post
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CHug when you demeth do u do a vacuum system?
I know that some big producers use a vacuum flash system following by a centrifuge.. the vacuum flash means the methanol is flashed off instantly to prevent the chance of a back reaction. Just plain heating and letting the methanol evaporate I believe is a very high chance of back reaction.

Have u found this?
 
Registered: March 02, 2009Reply With QuoteReport This Post
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