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Commercial Level Meth Recovery; What do you propose?
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Hi everyone,

You're as a whole the most knowledgable community of biodiesel enthusaists, and I've pulled endless amounts of knowledge from your posts; Now I need some 1 on 1 help Smile

We're looking at processing 1,000 Gallons a day of BD. The pickle I'm in is in regard to Methanol Recovery. The person we have consulting on building this plant has been trying to sell me on the idea of a 500 Gallon Propane tank, under vacuum, and that ALL of the glycerine is just going to fall out of the BD, and we'd be getting 10% of our , so I ask you..

What's the best way for us to remove methanol in a commercial scale enviroment, quickly, and cost effectively (as effective as possible that is)?

What % of recovery are we looking at on 1000 Gallons of BD?


And a follow-up question: After the demething, I planned on purchasing a Liquid-Liquid Centrifuge to polish the BD off to make it ATSM spec.

What do you guys think and recommend?

Thanks,
Ryan

This message has been edited. Last edited by: rpbio,
 
Registered: September 03, 2008Reply With QuoteReport This Post
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anybody?

Is the 500 Gallon Propane Tank under vacuum going to be able to get us 10% of our methanol back? Is 100% of the Glycerine going to drop out?

Cmon, you guys know these answers !
 
Registered: September 03, 2008Reply With QuoteReport This Post
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Second question first.
90%-95% of the glycerin will drop or in the first 8hrs or so of setting. The rest will settle out over several days. You did not indicate if you are talking about recovering the Methanol from the Bio portion or the Glycerin portion. You do not want to try to recover from both at same time or you risk forcing the reaction backwards.

If you are talking of recovering from the Bio portion, then its a question of are you going to be cleaning the fuel with resin (dry wash) or are you going with a GL1 process.

The first question tho is a little more straight forward. The Methanol recovered from the Glycerin portion should give you back more on the order of 20% - 25% of high purity Methanol of the amount put in. If you are recovering from the Bio portion that would give you from 5% to 10%. Of course this is all assumeing you are useing around 20% Methanol of the amount of oil. If you are trying to run the process on minimum amounts of Methanol then the amounts that can be recovered will be lower.

Trc


If you can't dazzel them with brilliance, then baffel them with bullchit.
 
Location: north of houston, south of dallas, east of austin | Registered: August 31, 2006Reply With QuoteReport This Post
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Thanks Trc,

I am interested in recovering it from the Bio,right after processing.

Instead of dry washing with resin I had planned on using a Liquid/Liquid Centrifuge to remove the remaining glycerin and any other impurities.

What do you think of that? Centrifuge over Dry Wash with resin?

We do use 20% of methanol, so figure a 1000 gallon batch of bio, 200 gallons of methanol, 10% recovery, 20 gallons methanol recovered per 1000 gallons of bio at optimum recovery.

That sounds pretty good, but we'd have a settling time of around 8 hours for 90-95% of the glycerin to drop out? Anyway to shorten that to maybe 2 hours?

Thanks for the help
Ryan
 
Registered: September 03, 2008Reply With QuoteReport This Post
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If your going to use centrifuge then you can get close to 100% without haveing to wait, the CF does the same job as settling but is much more expensive.

The centrifuge will not replace washing the fuel (either drywash or GL1 method or water wash), all it will do is cut out the wait time for glycerin to settle.

The real answer to it all tho is ASTM. There is a slight chance that right out of the CF that it will meet standards, (but really doubtful it will pass all the tests).

Trc


If you can't dazzel them with brilliance, then baffel them with bullchit.
 
Location: north of houston, south of dallas, east of austin | Registered: August 31, 2006Reply With QuoteReport This Post
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So what do you reccomend as far as the processes?

1) Biodiesel is processed , and let settle for 2 hours
2) Into 500G Propane Tank under Vacuum for Meth Recovery; How long should we let this do its thing?

3) Into centrifuge for removal of glycerin and water

Here's where I seem to have fallen off the horse.

I figured the CF would take care of my washing phase; What are the benefits of washing? What does it actually do?


Thanks TRC, you're really helping me out
 
Registered: September 03, 2008Reply With QuoteReport This Post



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So, you intend to go from never having made bio to making 1000 gallons a day? I have a 250 gallon processor and could conceivably make 1000 gallons a day but I am very glad I started out with a 40 gallon processor.
If I had a dollar for every post that starts out "First 500 gallon batch, all glop, what did I do wrong?" I'd have at least 50 bux.
Do yourself a favor and at least google the collabrative biodiesel tutorial and read it all, then you will at least have a starting point.
 
Location: West Michigan | Registered: April 26, 2006Reply With QuoteReport This Post
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We've made a whole lot of BD, heh. I personally, manage the business part of it more so than the hands on part. That's why I'm here asking you all for advice, because I want to make sure the person we have engineering our processes is doing things the most effective way for a commercial operation of 1000 Gallons a day.

I know with the 40 Gallon batches they washed,and then boiled the water off; we didn't even worry with methanol recovery at the time.

So my current questions would be:



Posted 28 September 2008 03:36 PM Hide Post
So what do you reccomend as far as the processes?

1) Biodiesel is processed , and let settle for 2 hours
2) Into 500G Propane Tank under Vacuum for Meth Recovery; How long should we let this do its thing?

3) Into centrifuge for removal of glycerin and water

Here's where I seem to have fallen off the horse.

I figured the CF would take care of my washing phase; What are the benefits of washing? What does it actually do?


Thanks
 
Registered: September 03, 2008Reply With QuoteReport This Post
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You have several things to consider. First is your centrifuge self cleaning? If it is you can come out of the processor and into the cf, if not you will need to figure out how much time you will spend cleaning the cf per batch. 2 hrs setteling befor. and draining off 90-95% may be quicker. second you still need to demeth the bio, regardless which way you go because meth in the bio will allow the bio to hold soap in solution. which ever method you use to demeth [wash][heat and vacume are probably the most cost effective] your bio you can then be run thru the cf to polish it.
 
Registered: July 04, 2006Reply With QuoteReport This Post
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We're looking at the Alfa Laval MAB 103; It's a Liquid/Liquid Centrifuge, but it's not a fan of solids.

I am under the impression that using KOH as our Catalyst will yeild us liquid glycerin as the byproduct, am I on par with that assumption?

So we need to remove the glycerin 1st and then demeth?


Demeth = Wash ? Synonymous basically?

Anti, as ya can see I'm running into problems as far as my order of processes goes on the backend of production heh

Edit: On the frontend of our process we have a solids removing centrifuge; it just is unable to seperate heavy and lightphase liquids also.
 
Registered: September 03, 2008Reply With QuoteReport This Post
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rp

the sequence would be

process
centrifuge to remove glycerin
demeth (if you demeth before you remove the glycerin you will be makeing oil from your bio)
then wash in some fashion to remove the trace salts and soaps (demething will only remove the methanol)

The reason water washing can be used to along with demething is that the water will attract the methanol.

Trc


If you can't dazzel them with brilliance, then baffel them with bullchit.
 
Location: north of houston, south of dallas, east of austin | Registered: August 31, 2006Reply With QuoteReport This Post
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okay so the bio runs through the centrifuge, the glycerin is all discarded into a container as the heavy phase liquid, I now have Bio with no glycerin in it.

I pump it over to the Demeth tank, and how long am I going to have to let it demeth? Assuming the glycerin is already out of the bio from the centrifuge.

At the end of the demething, I'd have Bio with no glycerin and no methanol.

Instead of the wash phase could I run it through the CF again to remove the trace amounts?

I know these questions all sound similar, haha I'm just trying to hammer it all out in my mind that we're going to be as efficient as possible.

Thanks
 
Registered: September 03, 2008Reply With QuoteReport This Post



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quote:
okay so the bio runs through the centrifuge, the glycerin is all discarded into a container as the heavy phase liquid, I now have Bio with no glycerin in it.


Correct except dont just disacard the glycerin, save it to do methanol recovery on it, the glycerin phase will be 25% to 30% Methanol.

quote:
I pump it over to the Demeth tank, and how long am I going to have to let it demeth? Assuming the glycerin is already out of the bio from the centrifuge.


How long will depend on several factors.

  • How fast you can put heat into the Bio.
  • How fast you can take heat off the condensate(Methonol vapor).
  • How well the system is engineered.


Remember a 'Demeth' system is either going to be a 'still' or a Flash evapotator, The still is more controllable and more sure, a Flash evaporator is going to be more expensive and less tolerant of any variations.

quote:
At the end of the demething, I'd have Bio with no glycerin and no methanol.


Virtually none possable to have trace amounts.

quote:
Instead of the wash phase could I run it through the CF again to remove the trace amounts?


Possable but I really doubt it. The only way to know for sure is to do ASTM testing. If you go ahead and run it thru a resin wash then it will be totally assured that it will then meet ASTM. If the bio already meet ASTM then the resin wont be noticably 'consumed', and will have a very long life. If it didnt meet ASTM then it will 'consume' and you will be on the safe side.

Since you are saying this is a commercial situation I am assumeing you are selling and Federal Law says it must meet ASTM, plus if an issue came up that could be fuel related and they came to test your fuel, and it not pass ASTM, then you could be liable for all damages.

Trc


If you can't dazzel them with brilliance, then baffel them with bullchit.
 
Location: north of houston, south of dallas, east of austin | Registered: August 31, 2006Reply With QuoteReport This Post
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You would be better off th demeth first, that way more glycerine will come out in one pass and the centrifuge process itself will flash off any traces of methanol, but always keep in mind every time you expose bio to air it gets one step closer to becoming polymerized
 
Location: West Michigan | Registered: April 26, 2006Reply With QuoteReport This Post
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Ok guys thanks,

How hot do we have to heat the bio being demethed?

When you say cool it down you mean the temperature of the Condensor?


So what are we thinking? Demeth 1st, remove glycerine via CF? or Remove Glycerine 1st via CF, then Demeth?
 
Registered: September 03, 2008Reply With QuoteReport This Post
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Looking back over this post,

I want to catch you guys all up to where we are.

We purchased the centrifuge, and as my knowledge on the subject has grown, I look at some of my questions on washing in utter embarrassment :P, but thank you very much for everyone who's answered my questions, and helped me put all the pieces together.

As far as "how hot to heat the bio", we're going to use a still type system, under vacuum, but I still am unsure as to how hot it's really going to have to get; We can hit 25 inches of mercury, so the vacuum will be fairly deep, I'm just unsure of the temperature we'll need to be at.

And since Fabricator and Antifuel are both knowledgable folks but have different views of the sequence of operations , I ask the question one more time ,

Demeth 1st , then pump to CF to remove Glycerin.

or CF out glycerin 1st, pump BD into Still and remove the remaining methanol, then run through resin for final polish.


thanks guys, as soon as everything is up and running as is planned and shiny and nice, I'll take some pics or a video or something
 
Registered: September 03, 2008Reply With QuoteReport This Post
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Process at as usual, let settle for as long as possible, at least 12 hours, drain off glycerine, distill in the processor or whatever still you have set up, distill until your pot temp reaches 200 degrees, then move to your fuge tank and fuge until the soap is at whatever level you are comfortable with.
I can get soap PPM to less than 100, but know that it may take 20 hours to get to this level depending on fuge size and GPM.
 
Location: West Michigan | Registered: April 26, 2006Reply With QuoteReport This Post
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Sorry I'm so late to the party, but I'll throw in my two cents worth...

If I were doing batches like you are I'd be very tempted to electrostatically settle the glycerin. Take the whole batch, glycerin and all, and electrostatically settle if for about an hour in a cone bottom tank, or in a separation rig on its way to the cone bottom tank.

Drain the glycerin off the bottom, run through your still process, then either split (use the FFAs for the next batch if you're doing acid esterification) or into the holding tank if you're not.

Pull the biodiesel off the top. Run that through your still to remove the methanol. Run the dry but soapy fuel through your centrifuge; most soap and virtually all the glycerin are removed by the 'fuge.

Split the soap if you run an acid stage.

Washing is now a piece of cake. Dry wash, water wash, centrifuge again and run through some purolite.

If you use NaOH you'll have better success removing soap with the centrifuge. As long as you split it with the acid promptly you don't have to worry about it solidifying on you. If your oil is so good you don't need an acid stage, I can only envy youSmile
 
Location: Maine, USA | Registered: July 06, 2007Reply With QuoteReport This Post



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I agree with the 10 - 15% methanol in the bio and 20 - 30% in the glycerol, and some has to stay bound up in the bio or else it would not be METHyl ester.

If you bubble air through the bio, methanol that has attached itself to water and soap and is held in suspension, is released and the water and soap drop out. Heating the bio to above 65C boils the methanol and it is released quicker.

If you water wash, the water falling down through the bio absorbes the methanol and thus releases the soaps and water allowing them to drop out. The methanol now in the wash water makes this a poor quality waste that has restrictions on how it should be disposed of.

By my estimates, if you recover methanol from both the bio and the water you should get back about 50% of original inputs. Just how pure it is,is the variable.


Slippery
Small steps taken one at a time
 
Location: Brisbane | Registered: January 30, 2007Reply With QuoteReport This Post
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According to my results which match all everything I have read there will never be over 5% methanol left in the bio before washing, usually from 2 to 4%.
 
Location: West Michigan | Registered: April 26, 2006Reply With QuoteReport This Post
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