Re: [biofuel] methanol recovery before separation
- Original Message - From: "Kenneth Kron" >Catching up on ancient email. >If one continues mixing until the reaction is complete and I have not >heard of any evidence that indicates separation is required for the >reaction to complete and then introduces into the reactor enough acid to >quench the sodium catalyst then I see no reason why you should not be >able to recover the methanol before separation. Kenneth, I can see a problem here if the process was single base and the feedstock was high in FFA. The addition of acid could convert the soap formed from the initial neutralisation back into FFA. Careful monitoring of the ammount of acid added might prevent this. Whilst FFA is a good fuel in itself its compatability with the components of a diesel engine is highly suspect. >In fact if you follow the "Fool proof method" then you do almost exactly >this. You separate the glycerin, mix it with phosphoric acid and mix it >back into your biodiesel. You've quenched the reaction right there and >have everything mixed up. If it's critical to add the acid to the >glycerin for some reason (which I don't quite see) you should have >plenty on hand from previous reactions. Another way to strip some of the methanol from the raw biodiesel would be to use glycerine from which the methanol had already been distilled.. Mix the raw biodiesel and the glycerine. The methanol will disperse 50/50 in the biodiesel and the glycerine. The methanol can be distilled from the glycerine. But would it be cost effective? Regards, Paul Gobert. Yahoo! Groups Sponsor -~--> Buy Ink Cartridges or Refill Kits for your HP, Epson, Canon or Lexmark Printer at MyInks.com. Free s/h on orders $50 or more to the US & Canada. http://www.c1tracking.com/l.asp?cid=5511 http://us.click.yahoo.com/mOAaAA/3exGAA/qnsNAA/FGYolB/TM -~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://infoarchive.net/sgroup/biofuel/ Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/biofuel/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [biofuel] methanol recovery before separation
Catching up on ancient email. If one continues mixing until the reaction is complete and I have not heard of any evidence that indicates separation is required for the reaction to complete and then introduces into the reactor enough acid to quench the sodium catalyst then I see no reason why you should not be able to recover the methanol before separation. In fact if you follow the "Fool proof method" then you do almost exactly this. You separate the glycerin, mix it with phosphoric acid and mix it back into your biodiesel. You've quenched the reaction right there and have everything mixed up. If it's critical to add the acid to the glycerin for some reason (which I don't quite see) you should have plenty on hand from previous reactions. kk Thomus Patton wrote: > Hello > > I'm a chemical engineering student working on a biodiesel production > facility design project with my senior design group at NCSU. We are > only in the initial stages and do not have a lot of kinetic data yet, > but I would think that removing methanol would certainly be > detrimental to your yield. I do not know if the resulting equilibrium > shift towards reactants would be more than you were willing to give up > or not, but something tells me it would certainly be noticeable based > on the fact that most recipes suggest using a large excess of alcohol > to push equilibrium towards the products (biodiesel and glycerin). > > lagonisa <[EMAIL PROTECTED]> wrote: > Hello to all: > > I have read some contributions to this group about methanol recovery > and the different options. I would like to try the recovery before > separation of bio and glycerol using a condenser that would receive > the methanol fumes after finishing the reaction. I have a processor > were I get 75¼C-80¼C as it is pressurized to 0,7 bar. The problem is > that I have also read that due to the reversibility of the reaction, > if after finishing my reaction I remove the methanol by reducing the > pressure and directing the vapours through a condenser, or even I > apply vacuum after despressurizing to do it faster, I can get a > reduction of the conversion transforming some biodiesel into oil > again. My question is: has anyone in this group measured or > experienced this fact? Is there a real decrease of the yield or > conversion? > > Lagonisa > > > [Non-text portions of this message have been removed] Yahoo! Groups Sponsor -~--> Buy Ink Cartridges or Refill Kits for your HP, Epson, Canon or Lexmark Printer at MyInks.com. Free s/h on orders $50 or more to the US & Canada. http://www.c1tracking.com/l.asp?cid=5511 http://us.click.yahoo.com/mOAaAA/3exGAA/qnsNAA/FGYolB/TM -~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://infoarchive.net/sgroup/biofuel/ Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/biofuel/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [biofuel] methanol recovery before separation
Maud, The design is very simple. It works and works well, but is very slow. Five gallons of input can be run through in between 2-3 hours. There's just not much surface area for the trickle to pass over - width wise that is - limiting recovery to but that one thin continual trickle of fluid. The model I saw was fired by oil candles. The owner had taken three empty tuna fish cans, pushed the top inward and down to create a ledge similar to what a burning cigarette could be placed on when used as a homemade ash tray. A hole was punched through the ledge, a crude fiber wick pushed through it and the can filled with vegetable oil. We were discussing ways to improve the volume/time ratio. The first improvement would be to create better egress for the alcohol vapor all along the length of the evaporator, rather than only through the manifold at the top. That would literaly be a work of plumbing art and largely out of reach of the abilities of all but a handful of shadetreers. About the only other way to increase the output is to increase the number of tubes, each one being an individual evaporator which would then require it's own heat source as well as needle valves, etc. The easiest way that we can think of to improve the design and improve output without creating a Frahnkensteen monstor is to scrap it in all but principle and move the rivulet concept over to a flat plate evaporator. We've had some minor setbacks with flat plates adopting their own random drain patterns, quickly losing partial use of the full width of the plate. If the rivulet concept were included by milling small channels from top to bottom of the plate and spaced every few milimeters apart, there would be a stable "sheeting" of fluid over a broad surface area. In fact, the milled channels would increase the surface area that the fluid is in contact with in comparison to a purely flat plate evaporator. 'Course redesign would require an increase in symetrically distributed heat, probably meaning a water jacket beneath the plate, along with a considerably enlarged version of the condensor - not necessarily any more space consumed but an increased number of condensor tubes. The design would probably end up looking something akin to two shoe boxes butted up to each other in a "T" fashion. Long story short? There's probably not much need to get too carried away with the simple design. I believe it was intended more as a test/proving unit. There are still some thoughts of converting it to a home unit if the output can be easily improved. Then there's always the issue of the open flame heat source - not a problem with someone capable and cautious enough to create a vapor tight system. Not so sure that everyone falls into those categories of abilities though. Todd Swearingen - Original Message - From: "Maud Essen" <[EMAIL PROTECTED]> To: Sent: Wednesday, December 24, 2003 10:43 AM Subject: Re: [biofuel] methanol recovery before separation > Todd, this is a wonderful description! Am I correct in thinking that > this device would work not only with the 5-gallon processor but also > with Mark's 40-gallon water heater processor? > > I'm going to try drawing this and will send it to you privately to > make sure I got it right. After the drawing is accurate, perhaps > Keith will want to post it. > > Maud > St. Louis, Missouri > > >Maud, > > > >Condensers are easy enough to fabricate. Your trick is probably going to be > >figuring out what to use as an evaporator. Pot stills are a large headache > >due to the fact that they start to fry the liquid before the alcohol has > >evaporated. The thinner the layer of fluid the better, as there's not as > >much liquid for the alcohol to move through before it escapes as vapor. > > > >One of the simpler "thin film evaporators" that I've seen is a 3 foot piece > >of 1" copper tubing set at a 15 degree angle with two or three tea lights > >set underneath at six inch intervals. A small resevoir with a drip valve is > >plumbed in near the top. At the very top of the 1" tube is a "T" with four > >1/2" tubes, 3' in length, branching off from it and angling downward. All > >four tie in at the bottom to a horizontal tube 1/2" in diameter, which is > >capped on one end and runs into a container on the other end.. > > > >The volume of the 4 tubes equals the volume of the 1 inch "evaporator" tube, > >so they can match the volume of whatever methanol evaporates in the 1" tube. > >The surface area of the 4 condensor tubes is double that of the 1" tube, so > >the heat will dissipate semi-quickly. > > > >If you can set the condensor tubes in a cold water bath there will be less > >c
Re: [biofuel] methanol recovery before separation
Todd, this is a wonderful description! Am I correct in thinking that this device would work not only with the 5-gallon processor but also with Mark's 40-gallon water heater processor? I'm going to try drawing this and will send it to you privately to make sure I got it right. After the drawing is accurate, perhaps Keith will want to post it. Maud St. Louis, Missouri >Maud, > >Condensers are easy enough to fabricate. Your trick is probably going to be >figuring out what to use as an evaporator. Pot stills are a large headache >due to the fact that they start to fry the liquid before the alcohol has >evaporated. The thinner the layer of fluid the better, as there's not as >much liquid for the alcohol to move through before it escapes as vapor. > >One of the simpler "thin film evaporators" that I've seen is a 3 foot piece >of 1" copper tubing set at a 15 degree angle with two or three tea lights >set underneath at six inch intervals. A small resevoir with a drip valve is >plumbed in near the top. At the very top of the 1" tube is a "T" with four >1/2" tubes, 3' in length, branching off from it and angling downward. All >four tie in at the bottom to a horizontal tube 1/2" in diameter, which is >capped on one end and runs into a container on the other end.. > >The volume of the 4 tubes equals the volume of the 1 inch "evaporator" tube, >so they can match the volume of whatever methanol evaporates in the 1" tube. >The surface area of the 4 condensor tubes is double that of the 1" tube, so >the heat will dissipate semi-quickly. > >If you can set the condensor tubes in a cold water bath there will be less >chance that the evaporator will produce more vapor than the condensor can >handle. The primary control over that is the rate of the drip from the >resevoir. You'll know if the evaporator/condensor is "tuned" properly by the >final volumes in each receiving container. > >A three foot run and a slow drip should be sufficient to evaporate all the >methanol out of the biodiesel without elevating it's temp beyond ~160*F. > >You'll want to make sure that both the container that receives the recovered >methanol and the container that receives the biodiesel (at the bottom of the >evaporator tube) are vapor tight and each has a vent hose running outside. >The vent is in case more vapor is produced than the condensor can handle. DO >NOT simply seal the methanol container, as any methanol vapor that the >condensor cannot handle (due to too fast a drip from the resevoir and/or too >much heat to the evaporator) can back down through the evaporator and >evacuate through the bottom. > >The vent hose on the container that receives the biodiesel is a precaution >for an overheated or over-fed evaporator. > >Todd Swearingen > >- Original Message - >From: "Maud Essen" <[EMAIL PROTECTED]> >To: >Sent: Thursday, December 18, 2003 8:41 PM >Subject: Re: [biofuel] methanol recovery before separation > > >> Thanks, Todd, for going to the trouble of running that test. >> >> Can I run my own tests like the one you described if I can figure out >> how to make a condenser? Although I'm currently at the small batch >> (two liter-sized) processing level, I would like to develop and >> practice using a small condenser before I "graduate" to a larger >> scale. >> >> There is a lot of distilling information on the web that describes >> how to build a condenser on large scale. If it's possible to scale >> one down, are there any guidelines for sizing one that would be >> appropriate at the five-gallon level? (I was going to try the >> flexible copper tubing used to install icemakers and the like.) >> >> Thanks again! >> >> Maud >> No breadmaker, no Cuisinart, no icemaker either >> St. Louis, Missouri >> >> >Maud, >> > >> >> is the amount of methanol remaining in the methyl ester >> >> considered negligible? Is it possible to determine what percentage >> >> remains in the methyl ester and what percentage in the glycerol? Maud >> > >> >Just for grins and giggles and to answer part of your question, a 100 > > >milileter sample of un-washed biodiesel was run through an evaporator. >(Not >> >much of an "average sampling.") >> > >> >100 milileters in and 97 milileters out. That would equate to an ~3% >volume >> >of alcohol residing in the fuel layer prior to alcohol recovery, or ~31 >> >milileters of alcohol for every liter of biodiesel. That's
Re: [biofuel] methanol recovery before separation
Maud, Condensers are easy enough to fabricate. Your trick is probably going to be figuring out what to use as an evaporator. Pot stills are a large headache due to the fact that they start to fry the liquid before the alcohol has evaporated. The thinner the layer of fluid the better, as there's not as much liquid for the alcohol to move through before it escapes as vapor. One of the simpler "thin film evaporators" that I've seen is a 3 foot piece of 1" copper tubing set at a 15 degree angle with two or three tea lights set underneath at six inch intervals. A small resevoir with a drip valve is plumbed in near the top. At the very top of the 1" tube is a "T" with four 1/2" tubes, 3' in length, branching off from it and angling downward. All four tie in at the bottom to a horizontal tube 1/2" in diameter, which is capped on one end and runs into a container on the other end.. The volume of the 4 tubes equals the volume of the 1 inch "evaporator" tube, so they can match the volume of whatever methanol evaporates in the 1" tube. The surface area of the 4 condensor tubes is double that of the 1" tube, so the heat will dissipate semi-quickly. If you can set the condensor tubes in a cold water bath there will be less chance that the evaporator will produce more vapor than the condensor can handle. The primary control over that is the rate of the drip from the resevoir. You'll know if the evaporator/condensor is "tuned" properly by the final volumes in each receiving container. A three foot run and a slow drip should be sufficient to evaporate all the methanol out of the biodiesel without elevating it's temp beyond ~160*F. You'll want to make sure that both the container that receives the recovered methanol and the container that receives the biodiesel (at the bottom of the evaporator tube) are vapor tight and each has a vent hose running outside. The vent is in case more vapor is produced than the condensor can handle. DO NOT simply seal the methanol container, as any methanol vapor that the condensor cannot handle (due to too fast a drip from the resevoir and/or too much heat to the evaporator) can back down through the evaporator and evacuate through the bottom. The vent hose on the container that receives the biodiesel is a precaution for an overheated or over-fed evaporator. Todd Swearingen - Original Message ----- From: "Maud Essen" <[EMAIL PROTECTED]> To: Sent: Thursday, December 18, 2003 8:41 PM Subject: Re: [biofuel] methanol recovery before separation > Thanks, Todd, for going to the trouble of running that test. > > Can I run my own tests like the one you described if I can figure out > how to make a condenser? Although I'm currently at the small batch > (two liter-sized) processing level, I would like to develop and > practice using a small condenser before I "graduate" to a larger > scale. > > There is a lot of distilling information on the web that describes > how to build a condenser on large scale. If it's possible to scale > one down, are there any guidelines for sizing one that would be > appropriate at the five-gallon level? (I was going to try the > flexible copper tubing used to install icemakers and the like.) > > Thanks again! > > Maud > No breadmaker, no Cuisinart, no icemaker either > St. Louis, Missouri > > >Maud, > > > >> is the amount of methanol remaining in the methyl ester > >> considered negligible? Is it possible to determine what percentage > >> remains in the methyl ester and what percentage in the glycerol? Maud > > > >Just for grins and giggles and to answer part of your question, a 100 > >milileter sample of un-washed biodiesel was run through an evaporator. (Not > >much of an "average sampling.") > > > >100 milileters in and 97 milileters out. That would equate to an ~3% volume > >of alcohol residing in the fuel layer prior to alcohol recovery, or ~31 > >milileters of alcohol for every liter of biodiesel. That's ~15% of the > >original volume of alcohol. > > > >Not exactly insignificant. But then common sense never dictated that it > >would be. > > > >One qualifier. The unwashed fuel used to scratch out this number was from an > >aggregate vessel that is filled with fuel from multiple reactions, both > >straight base, acid/base, high volumes of alcohol per liter (250 ml) and > >standard volumes (200 ml). > > > >Still, I would assess 2%-3% as a conservatively safe value, at least until > >more refined numbers pop up. > > > >Todd Swearingen > > > > > >Biofuel at Journey to Forever: > >http://journeytoforever.org/biofuel.html > > > >Biofuels l
Re: [biofuel] methanol recovery before separation
Thanks, Todd, for going to the trouble of running that test. Can I run my own tests like the one you described if I can figure out how to make a condenser? Although I'm currently at the small batch (two liter-sized) processing level, I would like to develop and practice using a small condenser before I "graduate" to a larger scale. There is a lot of distilling information on the web that describes how to build a condenser on large scale. If it's possible to scale one down, are there any guidelines for sizing one that would be appropriate at the five-gallon level? (I was going to try the flexible copper tubing used to install icemakers and the like.) Thanks again! Maud No breadmaker, no Cuisinart, no icemaker either St. Louis, Missouri >Maud, > >> is the amount of methanol remaining in the methyl ester >> considered negligible? Is it possible to determine what percentage >> remains in the methyl ester and what percentage in the glycerol? Maud > >Just for grins and giggles and to answer part of your question, a 100 >milileter sample of un-washed biodiesel was run through an evaporator. (Not >much of an "average sampling.") > >100 milileters in and 97 milileters out. That would equate to an ~3% volume >of alcohol residing in the fuel layer prior to alcohol recovery, or ~31 >milileters of alcohol for every liter of biodiesel. That's ~15% of the >original volume of alcohol. > >Not exactly insignificant. But then common sense never dictated that it >would be. > >One qualifier. The unwashed fuel used to scratch out this number was from an >aggregate vessel that is filled with fuel from multiple reactions, both >straight base, acid/base, high volumes of alcohol per liter (250 ml) and >standard volumes (200 ml). > >Still, I would assess 2%-3% as a conservatively safe value, at least until >more refined numbers pop up. > >Todd Swearingen > > >Biofuel at Journey to Forever: >http://journeytoforever.org/biofuel.html > >Biofuels list archives: >http://archive.nnytech.net/index.php?list=biofuel > >Please do NOT send Unsubscribe messages to the list address. >To unsubscribe, send an email to: >[EMAIL PROTECTED] > > >Yahoo! Groups Links > >To visit your group on the web, go to: > http://groups.yahoo.com/group/biofuel/ > >To unsubscribe from this group, send an email to: > [EMAIL PROTECTED] > >Your use of Yahoo! Groups is subject to: > http://docs.yahoo.com/info/terms/ Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/index.php?list=biofuel Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/biofuel/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [biofuel] methanol recovery before separation
Maud, > is the amount of methanol remaining in the methyl ester > considered negligible? Is it possible to determine what percentage > remains in the methyl ester and what percentage in the glycerol? Maud Just for grins and giggles and to answer part of your question, a 100 milileter sample of un-washed biodiesel was run through an evaporator. (Not much of an "average sampling.") 100 milileters in and 97 milileters out. That would equate to an ~3% volume of alcohol residing in the fuel layer prior to alcohol recovery, or ~31 milileters of alcohol for every liter of biodiesel. That's ~15% of the original volume of alcohol. Not exactly insignificant. But then common sense never dictated that it would be. One qualifier. The unwashed fuel used to scratch out this number was from an aggregate vessel that is filled with fuel from multiple reactions, both straight base, acid/base, high volumes of alcohol per liter (250 ml) and standard volumes (200 ml). Still, I would assess 2%-3% as a conservatively safe value, at least until more refined numbers pop up. Todd Swearingen Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/index.php?list=biofuel Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Yahoo! Groups Sponsor -~--> Buy Ink Cartridges or Refill Kits for your HP, Epson, Canon or Lexmark Printer at MyInks.com. Free s/h on orders $50 or more to the US & Canada. http://www.c1tracking.com/l.asp?cid=5511 http://us.click.yahoo.com/mOAaAA/3exGAA/qnsNAA/FGYolB/TM -~-> Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/biofuel/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [biofuel] methanol recovery before separation
Hi again Todd
As far as the wash-water's concerned, water hyacinths quite happily
eat the first-wash water, methanol and all, clean it up nicely. Well,
actually it's a mix of water hyacinths and two types of duckweed,
about both of which there's much good information to be found at JtF:
http://journeytoforever.org/edu_pond.html#duckweed
http://journeytoforever.org/edu_pond.html#waterhyacinth
The washwater is innocuous enough, apart from the methanol - no heavy
metals or toxins, for instance, so the plants themselves remain
usable. Both make excellent compost, and that's a satisfactory
solution - not as satisfactory as reusing the excess methanol, but
you are recycling it well. Aslo the plants break the stuff down,
they're not full of methanol and lye, and still make good livestock
feed.
Best
Keith
>Maud,
>
>I wouldn't consider the MeOH content in the biodiesel to be negligible. Not
>at all.
>
>Unfortunately, many others consider it so.
>
>Simplest method to determine the volume of MeOH that resides in the
>biodiesel and glycerol, as well as the volume that was consumed in reaction,
>is to measure the volumes of alcohol laden biodiesel and glycerol, evaporate
>the MeOH and then measure the remaining volumes of each.
>
>The easiest way, IMNSHO, to determine if the MeOH volume in the biodiesel
>fraction is negligible is to stick one's nose over a container and huff it.
>(Not advised, but the point being made should be easy enough to decipher.)
>Without removing the alcohol you've got a fluid that has a flashpoint
>essentially the same as methanol, rather than the rather safe flashpoint of
>biodiesel.
>
>To test that theory, take a piece of cotton wick, anchor it in a 6 ounce
>metal tomato paste can as if you're going to make a candle. Fill the can
>with MeOH laden biodiesel. Light the wick as if the can were an oil candle.
>Sit back and watch. Everything goes fine for a bit, that is until the fuel
>heats up to the boiling point of alcohol. Then you have a runaway alcohol
>torch.
>
>That's the same alochol that would "normally" get washed down someone's
>drain or flushed out into the back forty. The same stuff that a lot of
>people consider "insignificant."
>
>We haven't yet taken any time to quantify the average volume of MeOH that
>remains in the biodiesel. But it is a safe bet that the ratio is consistent
>between the biodiesel and glycerol fractions no matter how much alcohol is
>originally used. The more alcohol used in the reaction, the more alcohol
>will remain in the biodiesel and end up in the wastewater stream if
>evaporation is not conducted prior.
>
>Most people have probably noticed that MeOH and biodiesel are completely
>miscible in each other in any volume.
>
>If a person is worried about the energy inputs required to recover the
>alcohol from the biodiesel, then they should be looking at insulation, heat
>recovery and renewable fuels for the energy inputs.
>
>Todd Swearingen
>
>- Original Message -
>From: "Maud Essen" <[EMAIL PROTECTED]>
>To:
>Sent: Saturday, December 13, 2003 7:08 PM
>Subject: Re: [biofuel] methanol recovery before separation
>
>
>Todd, is the amount of methanol remaining in the methyl ester
>considered negligible? Is it possible to determine what percentage
>remains in the methyl ester and what percentage in the glycerol? Maud
>
> >Lagonisa,
> >
> >> The problem is
> >> that I have also read that due to the reversibility of the reaction,
> >
> >The reaction is not exactly reversible. "Reversability" would require the
> >three glycerides and the glycerol recombining. That doesn't happen. Once
>the
> >glycerol is cleaved it is out of the picture.
> >
> >You're suggesting MeOH recovery at the point where the reaction is complete
> >and the glycerol has yet to settle out. However, that's not altogether
> >adisable due to the continual mixing of excess catalyst with the methyl
> >ester.
> >
> >If you reduce the volume of alcohol via evaporation at this point there
> >would be a propensity for some of the ester to fracture ("back crack") into
> >FFAs and then convert to soap. Mind you that "back cracking" can only occur
> >up to the point that all the catalyst is consumed in soap making.
> >
> >If you can monitor the reaction and insure that the balance of catalyst is
> >infintesimally small beyond what is required to guarantee 100% completion,
> >erego yielding but a small and controlled amount of extra soap production,
> >then there might be some merit in extracting the alcohol prior to the
> &g
Re: [biofuel] methanol recovery before separation
>Lagonisa,
>
> > The problem is
> > that I have also read that due to the reversibility of the reaction,
>
>The reaction is not exactly reversible. "Reversability" would require the
>three glycerides and the glycerol recombining. That doesn't happen. Once the
>glycerol is cleaved it is out of the picture.
>
>You're suggesting MeOH recovery at the point where the reaction is complete
>and the glycerol has yet to settle out. However, that's not altogether
>adisable due to the continual mixing of excess catalyst with the methyl
>ester.
>
>If you reduce the volume of alcohol via evaporation at this point there
>would be a propensity for some of the ester to fracture ("back crack") into
>FFAs and then convert to soap. Mind you that "back cracking" can only occur
>up to the point that all the catalyst is consumed in soap making.
>
>If you can monitor the reaction and insure that the balance of catalyst is
>infintesimally small beyond what is required to guarantee 100% completion,
>erego yielding but a small and controlled amount of extra soap production,
>then there might be some merit in extracting the alcohol prior to the
>glycerin cocktail settling.
>
>Otherwise? Probably none.
>
>Todd Swearingen
Hi Todd
Yet that's what Dale Scroggins does, apparently with good results.
The touchless processor
http://journeytoforever.org/biodiesel_processor.html#touchfree
http://home.swbell.net/scrof/Biod_Proc.html
Michael Allen and Gumpon Prateepchaikul's set-up at Prince of Songkla
University in Thailand also reclaims the methanol at the end of the
processing stage, though differently, and with high efficiency and a
high-quality product (they test it).
I wonder if this isn't somewhat theoretical, as with the idea that
using acid in the wash will definitely backsplit biodiesel to FFAs
and must definitely be avoided. If properly done - which of course
shouldn't be merely so solve an emulsion problem (improve the
process!) - it has the advantage of thoroughly neutralizing the
catalyst, at the cost of traces of FFA which remain well within the
standard specs.
So here the same perhaps applies, as you indicate - a well-controlled
process with the right amount of catalyst and the right amount of
everything else too.
Needs and economics will differ from case to case, and I think
methanol recovery should be an option at each of the three possible
stages it can be done - straight after processing, using the existing
heat (to start with), recovering excess methanol from both the ester
and the by-product; recovering the excess methanol from the
by-product cocktail (that is most of it), which leaves the balance to
be accounted for (in the first wash water); recovering the excess
methanol from the glycerine itself after separating the by-product
components (which still leaves the balance in the first wash water).
Best
Keith
> > Hello to all:
> >
> > I have read some contributions to this group about methanol recovery
> > and the different options. I would like to try the recovery before
> > separation of bio and glycerol using a condenser that would receive
> > the methanol fumes after finishing the reaction. I have a processor
> > were I get 75¼C-80¼C as it is pressurized to 0,7 bar. The problem is
> > that I have also read that due to the reversibility of the reaction,
> > if after finishing my reaction I remove the methanol by reducing the
> > pressure and directing the vapours through a condenser, or even I
> > apply vacuum after despressurizing to do it faster, I can get a
> > reduction of the conversion transforming some biodiesel into oil
> > again. My question is: has anyone in this group measured or
> > experienced this fact? Is there a real decrease of the yield or
> > conversion?
> >
> > Lagonisa
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Re: [biofuel] methanol recovery before separation
Maud,
I wouldn't consider the MeOH content in the biodiesel to be negligible. Not
at all.
Unfortunately, many others consider it so.
Simplest method to determine the volume of MeOH that resides in the
biodiesel and glycerol, as well as the volume that was consumed in reaction,
is to measure the volumes of alcohol laden biodiesel and glycerol, evaporate
the MeOH and then measure the remaining volumes of each.
The easiest way, IMNSHO, to determine if the MeOH volume in the biodiesel
fraction is negligible is to stick one's nose over a container and huff it.
(Not advised, but the point being made should be easy enough to decipher.)
Without removing the alcohol you've got a fluid that has a flashpoint
essentially the same as methanol, rather than the rather safe flashpoint of
biodiesel.
To test that theory, take a piece of cotton wick, anchor it in a 6 ounce
metal tomato paste can as if you're going to make a candle. Fill the can
with MeOH laden biodiesel. Light the wick as if the can were an oil candle.
Sit back and watch. Everything goes fine for a bit, that is until the fuel
heats up to the boiling point of alcohol. Then you have a runaway alcohol
torch.
That's the same alochol that would "normally" get washed down someone's
drain or flushed out into the back forty. The same stuff that a lot of
people consider "insignificant."
We haven't yet taken any time to quantify the average volume of MeOH that
remains in the biodiesel. But it is a safe bet that the ratio is consistent
between the biodiesel and glycerol fractions no matter how much alcohol is
originally used. The more alcohol used in the reaction, the more alcohol
will remain in the biodiesel and end up in the wastewater stream if
evaporation is not conducted prior.
Most people have probably noticed that MeOH and biodiesel are completely
miscible in each other in any volume.
If a person is worried about the energy inputs required to recover the
alcohol from the biodiesel, then they should be looking at insulation, heat
recovery and renewable fuels for the energy inputs.
Todd Swearingen
- Original Message -
From: "Maud Essen" <[EMAIL PROTECTED]>
To:
Sent: Saturday, December 13, 2003 7:08 PM
Subject: Re: [biofuel] methanol recovery before separation
Todd, is the amount of methanol remaining in the methyl ester
considered negligible? Is it possible to determine what percentage
remains in the methyl ester and what percentage in the glycerol? Maud
>Lagonisa,
>
>> The problem is
>> that I have also read that due to the reversibility of the reaction,
>
>The reaction is not exactly reversible. "Reversability" would require the
>three glycerides and the glycerol recombining. That doesn't happen. Once
the
>glycerol is cleaved it is out of the picture.
>
>You're suggesting MeOH recovery at the point where the reaction is complete
>and the glycerol has yet to settle out. However, that's not altogether
>adisable due to the continual mixing of excess catalyst with the methyl
>ester.
>
>If you reduce the volume of alcohol via evaporation at this point there
>would be a propensity for some of the ester to fracture ("back crack") into
>FFAs and then convert to soap. Mind you that "back cracking" can only occur
>up to the point that all the catalyst is consumed in soap making.
>
>If you can monitor the reaction and insure that the balance of catalyst is
>infintesimally small beyond what is required to guarantee 100% completion,
>erego yielding but a small and controlled amount of extra soap production,
>then there might be some merit in extracting the alcohol prior to the
>glycerin cocktail settling.
>
>Otherwise? Probably none.
>
>Todd Swearingen
>
>> Hello to all:
>>
>> I have read some contributions to this group about methanol recovery
>> and the different options. I would like to try the recovery before
>> separation of bio and glycerol using a condenser that would receive
>> the methanol fumes after finishing the reaction. I have a processor
>> were I get 75¼C-80¼C as it is pressurized to 0,7 bar. The problem is
>> that I have also read that due to the reversibility of the reaction,
>> if after finishing my reaction I remove the methanol by reducing the
>> pressure and directing the vapours through a condenser, or even I
>> apply vacuum after despressurizing to do it faster, I can get a
>> reduction of the conversion transforming some biodiesel into oil
>> again. My question is: has anyone in this group measured or
>> experienced this fact? Is there a real decrease of the yield or
>> conversion?
>>
>> Lagonisa
>>
>>
>>
>> Yahoo! Groups SponsorADVERTISEMENT
>>
>> Biofuel at Jo
Re: [biofuel] methanol recovery before separation
Todd, is the amount of methanol remaining in the methyl ester
considered negligible? Is it possible to determine what percentage
remains in the methyl ester and what percentage in the glycerol? Maud
>Lagonisa,
>
>> The problem is
>> that I have also read that due to the reversibility of the reaction,
>
>The reaction is not exactly reversible. "Reversability" would require the
>three glycerides and the glycerol recombining. That doesn't happen. Once the
>glycerol is cleaved it is out of the picture.
>
>You're suggesting MeOH recovery at the point where the reaction is complete
>and the glycerol has yet to settle out. However, that's not altogether
>adisable due to the continual mixing of excess catalyst with the methyl
>ester.
>
>If you reduce the volume of alcohol via evaporation at this point there
>would be a propensity for some of the ester to fracture ("back crack") into
>FFAs and then convert to soap. Mind you that "back cracking" can only occur
>up to the point that all the catalyst is consumed in soap making.
>
>If you can monitor the reaction and insure that the balance of catalyst is
>infintesimally small beyond what is required to guarantee 100% completion,
>erego yielding but a small and controlled amount of extra soap production,
>then there might be some merit in extracting the alcohol prior to the
>glycerin cocktail settling.
>
>Otherwise? Probably none.
>
>Todd Swearingen
>
>> Hello to all:
>>
>> I have read some contributions to this group about methanol recovery
>> and the different options. I would like to try the recovery before
>> separation of bio and glycerol using a condenser that would receive
>> the methanol fumes after finishing the reaction. I have a processor
>> were I get 75¼C-80¼C as it is pressurized to 0,7 bar. The problem is
>> that I have also read that due to the reversibility of the reaction,
>> if after finishing my reaction I remove the methanol by reducing the
>> pressure and directing the vapours through a condenser, or even I
>> apply vacuum after despressurizing to do it faster, I can get a
>> reduction of the conversion transforming some biodiesel into oil
>> again. My question is: has anyone in this group measured or
>> experienced this fact? Is there a real decrease of the yield or
>> conversion?
>>
>> Lagonisa
>>
>>
>>
>> Yahoo! Groups SponsorADVERTISEMENT
>>
>> Biofuel at Journey to Forever:
>> http://journeytoforever.org/biofuel.html
>>
>> Biofuels list archives:
>> http://archive.nnytech.net/index.php?list=biofuel
>>
>> Please do NOT send Unsubscribe messages to the list address.
> > To unsubscribe, send an email to:
> > [EMAIL PROTECTED]
> >
> > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
> >
> >
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>> [Non-text portions of this message have been removed]
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>>
>>
>>
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>>
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>>
>>
>
>
>
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Re: [biofuel] methanol recovery before separation
Lagonisa,
> The problem is
> that I have also read that due to the reversibility of the reaction,
The reaction is not exactly reversible. "Reversability" would require the
three glycerides and the glycerol recombining. That doesn't happen. Once the
glycerol is cleaved it is out of the picture.
You're suggesting MeOH recovery at the point where the reaction is complete
and the glycerol has yet to settle out. However, that's not altogether
adisable due to the continual mixing of excess catalyst with the methyl
ester.
If you reduce the volume of alcohol via evaporation at this point there
would be a propensity for some of the ester to fracture ("back crack") into
FFAs and then convert to soap. Mind you that "back cracking" can only occur
up to the point that all the catalyst is consumed in soap making.
If you can monitor the reaction and insure that the balance of catalyst is
infintesimally small beyond what is required to guarantee 100% completion,
erego yielding but a small and controlled amount of extra soap production,
then there might be some merit in extracting the alcohol prior to the
glycerin cocktail settling.
Otherwise? Probably none.
Todd Swearingen
> Hello to all:
>
> I have read some contributions to this group about methanol recovery
> and the different options. I would like to try the recovery before
> separation of bio and glycerol using a condenser that would receive
> the methanol fumes after finishing the reaction. I have a processor
> were I get 75¼C-80¼C as it is pressurized to 0,7 bar. The problem is
> that I have also read that due to the reversibility of the reaction,
> if after finishing my reaction I remove the methanol by reducing the
> pressure and directing the vapours through a condenser, or even I
> apply vacuum after despressurizing to do it faster, I can get a
> reduction of the conversion transforming some biodiesel into oil
> again. My question is: has anyone in this group measured or
> experienced this fact? Is there a real decrease of the yield or
> conversion?
>
> Lagonisa
>
>
>
> Yahoo! Groups SponsorADVERTISEMENT
>
> Biofuel at Journey to Forever:
> http://journeytoforever.org/biofuel.html
>
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>
> Please do NOT send Unsubscribe messages to the list address.
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>
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> [Non-text portions of this message have been removed]
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>
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Re: [biofuel] methanol recovery before separation
On Saturday, December 13, 2003, at 12:02 PM, Thomus Patton wrote: > I would think that removing methanol would certainly be detrimental > to your yield. So would I. Most of the methanol goes into the aqueous (glycerine) layer anyway, so you can recover that portion by distilling the glyc layer alone, after separating. -K Yahoo! Groups Sponsor -~--> Buy Ink Cartridges or Refill Kits for your HP, Epson, Canon or Lexmark Printer at MyInks.com. Free s/h on orders $50 or more to the US & Canada. http://www.c1tracking.com/l.asp?cid=5511 http://us.click.yahoo.com/mOAaAA/3exGAA/qnsNAA/FGYolB/TM -~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/index.php?list=biofuel Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
Re: [biofuel] methanol recovery before separation
Hello I'm a chemical engineering student working on a biodiesel production facility design project with my senior design group at NCSU. We are only in the initial stages and do not have a lot of kinetic data yet, but I would think that removing methanol would certainly be detrimental to your yield. I do not know if the resulting equilibrium shift towards reactants would be more than you were willing to give up or not, but something tells me it would certainly be noticeable based on the fact that most recipes suggest using a large excess of alcohol to push equilibrium towards the products (biodiesel and glycerin). lagonisa <[EMAIL PROTECTED]> wrote: Hello to all: I have read some contributions to this group about methanol recovery and the different options. I would like to try the recovery before separation of bio and glycerol using a condenser that would receive the methanol fumes after finishing the reaction. I have a processor were I get 75¼C-80¼C as it is pressurized to 0,7 bar. The problem is that I have also read that due to the reversibility of the reaction, if after finishing my reaction I remove the methanol by reducing the pressure and directing the vapours through a condenser, or even I apply vacuum after despressurizing to do it faster, I can get a reduction of the conversion transforming some biodiesel into oil again. My question is: has anyone in this group measured or experienced this fact? Is there a real decrease of the yield or conversion? Lagonisa Yahoo! Groups SponsorADVERTISEMENT Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/index.php?list=biofuel Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. - Do you Yahoo!? Free Pop-Up Blocker - Get it now [Non-text portions of this message have been removed] Yahoo! Groups Sponsor -~--> Buy Ink Cartridges or Refill Kits for your HP, Epson, Canon or Lexmark Printer at MyInks.com. Free s/h on orders $50 or more to the US & Canada. http://www.c1tracking.com/l.asp?cid=5511 http://us.click.yahoo.com/mOAaAA/3exGAA/qnsNAA/FGYolB/TM -~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/index.php?list=biofuel Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
