Re: [biofuels-biz] skin on biodiesel
- Original Message - From: Keith Addison [EMAIL PROTECTED] Subject: Re: [biofuels-biz] skin on biodiesel Hi Paul, Michael How do you maintain the heat during the processing hour, Paul? Keith as this is trully a bucket method of temporary production I don't maintain the 55 deg. The plastic bucket loses heat slowly. You're using an aqueous solution of catalyst to make methoxide? Yes Wouldn't draining off the glycerine as soon as possible also drain off some excess methanol? By draining off as soon as possible I mean after the final settling after last stirring, reaction should have gone as far as it can go by then without further heat and stirring. Methanol excess to reaction will have dispersed itself in both BD and glycerine. If there is to be no further reaction, the more excess methanol that comes off in the glycerine the better. And doesn't severe emulsification during washing indicate high levels of unconverted materials? That seems to be the general concensus, would say that the higher levels of alkali ensure better reaction, this of course could be specific to my production methods and trials, a more complete reaction process may produce the same results with lower levels of alkali. SG and viscosity testing won't necessarily give you an indication of that. No, the production of lower SG and viscosity was quoted as an observation of what also happens with higher than titration indicated alkali levels. Regards, Paul Gobert Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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: [biofuels-biz] skin on biodiesel/suggestions
Though wash problems weren't a main point of this thread, they've come up again in there, so... Let's not forget that soaps (I guess I've made this point in this thread already) also cause wash problems, along with the wash problems caused by poor conversion. I think when you have emulsification (sounds like Paul did a few weeks ago, and I'm wondering if it's related to his skin/middle layer formation), it's hard to tell what causes it, without testing. It's good idea to do some sleuthing to try to figure out what caused it and to try and to determine which of the two conditions it is- soaps of poor conversion. Soapy biodiesel I've made also produced skins and middle layers that I assume were soaps. the soaps bit correlated to high initial pH and then to washing problems. And to very, very white first wash water once it did separate Maybe I'm wrong about this, but in my experience the skin formation correlates to higher pH, and to wash problems. I assume when I see a skin or a transluscent, greyish middle layer, it's a sign that a hard wash is coming. For me this means that there was water in the oil, or that I used too much catalyst, or that it was high-ffa oil (which I almost never work with unless I'm doing it to make a point to students or something). Some biodiesel I'm working with right now (we made 150-200 gallons before realizing that it emulsifies like crazy in the wash, our mistake in getting slack on doing regular quality testing) has the opposite problem, emulsifying but the pH looked like it was going to be decent fuel. I reprocessed some and a lot of glycerine dropped out on that batch, so I;'m leaning towards poor conversion rather than soaps etc as the source of the problem. I agree that we all might be talking about several different skin-forming phenomena here, though. I personally have very little experience with animal fats as feedstock, and I know that animal fats can introduce some other variables into the picture than vegetable oils. Paul, you're working with several variables that could potentially lead to either soaps or to poor conversion. My suggestion is for you to try to eliminate some of these variables by trying a trial with some very conventional processing to get a 'baseline' idea of how that oil might behave. Conventional in my mind includes: 1. DG and MG: eliminate agitation as a variable by running a long 1-hour agitation on a bucket-batch, drill/paintstirrer-agitated, maybe pulling some samples at 15-minute intervals to run tests on, to see what role agitation plays in the fuel quality. 2. DG and MG again: get the temperature up somehow. Try to make sure your small 10L batches don't lose heat so fast. I've done 2-stage in 10-liter batches and it requires a lot of reheating to remain at proper temperature. Of course it might be more crucial in two-stage acid/base, or maybe not... it seems that with singlestage some people have had problems with improper temperature as well. A hot water bath for the jugs you're using, or an immersion heater for a 5-gallon metal can, or a hotwater heater element for the same metal can, or doing a 10-liter batch in a canning kettle on a hot plate (still drill-agitated)... 3. Soaps: eliminate water as a variable and use a non- conc. aqueous process just for this trial. 4. Soaps: again, eliminate water as a variable by dewatering the oil you';re using. 5. catalyst quantity: trial and error batches, assume that you don't know what the base amount of catalyst should be for that particular oil. Work with 3.5 on up to 5 g base catalyst (for NaOH anyway) 6. conversion % again: Make sure your methanol doesn't evaporate, though in jugs it shouldn't 7. eliminate the 'glycerine draining' variable, though I can't see what difference this should make, doesn't seem harmful to me. 8 then try your entire own process, jugs, conc aqueous, low agitation, and all, with some totally different feedstock oil... Good luck! Mark At 07:11 PM 12/16/2002 +1000, you wrote: - Original Message - From: Keith Addison [EMAIL PROTECTED] Subject: Re: [biofuels-biz] skin on biodiesel Hi Paul, Michael How do you maintain the heat during the processing hour, Paul? Keith as this is trully a bucket method of temporary production I don't maintain the 55 deg. The plastic bucket loses heat slowly. You're using an aqueous solution of catalyst to make methoxide? Yes Wouldn't draining off the glycerine as soon as possible also drain off some excess methanol? By draining off as soon as possible I mean after the final settling after last stirring, reaction should have gone as far as it can go by then without further heat and stirring. Methanol excess to reaction will have dispersed itself in both BD and glycerine. If there is to be no further reaction, the more excess methanol that comes off in the glycerine the better. And doesn't severe emulsification during washing indicate high levels
Re: [biofuels-biz] skin on biodiesel
Thanks Paul, I'll try to follow that up. Currently in Thailand, we wash the BD made from stearin with almost indecent haste. Of course, if the skin comes from near the BD/glycerol interface, we should suspect methanol evaporating from the glycerol. So is the skin on the top of the BD or really on top of the glycerol? Others participants have already raised the matter of 1) whether it is BD soluble or 2) water soluble 3) Affected by separation time, 4) Disappears in the wash. Are we sure we are all talking about the same skin Thanks again Paul - there is nothing like a few facts to muck up a perfectly good theory! : - ) Michael Allen 12/12/02 00:39:00, rpg [EMAIL PROTECTED] wrote: Michael, have noticed that raw biodiesel from tallow readily forms a skin as it cools, but the same BD after washing does not. Paul Gobert. Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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/ Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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: [biofuels-biz] skin on biodiesel
- Original Message - From: Michael Allen [EMAIL PROTECTED] Subject: Re: [biofuels-biz] skin on biodiesel Thanks Paul, I'll try to follow that up. Currently in Thailand, we wash the BD made from stearin with almost indecent haste. Of course, if the skin comes from near the BD/glycerol interface, we should suspect methanol evaporating from the glycerol. So is the skin on the top of the BD or really on top of the glycerol? Others participants have already raised the matter of 1) whether it is BD soluble or 2) water soluble 3) Affected by separation time, 4) Disappears in the wash. Are we sure we are all talking about the same skin Thanks again Paul - there is nothing like a few facts to muck up a perfectly good theory! : - ) Michael Allen Michael, building new processor . At the moment I make BD in 10l batches in 15L plastic drums hand shaken. The mix is poured into 20L plastic pails where it is stirred intermittently over a period of an hour. The settling time for the glycerine reduces with each stir. As the drums are filled a thin skim/film forms on the surface of the BD. This film readily redissolves. (perhaps its polimerisation under the influence of the air ). The only problems I have had with the BD/glycerine interface is when using high levels of alkali (above titration levels) in the single stage alkali process. I like to drain the glycerine as soon as possible as extended contact of BD/alkaline glycerine tends to form a jelly like material at the interface which makes washing very difficult (emulsification). As long as the glycerine is drained off early, have found that higher than titration levels of alkali give easier washing. Prefer to use higher than titration levels of alkali, gives lower yield volume but a Bd with lower SG and viscosities. Hope that helps, Paul Gobert. Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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: [biofuels-biz] skin on biodiesel
Hi Paul, Michael How do you maintain the heat during the processing hour, Paul? You're using an aqueous solution of catalyst to make methoxide? Wouldn't draining off the glycerine as soon as possible also drain off some excess methanol? And doesn't severe emulsification during washing indicate high levels of unconverted materials? SG and viscosity testing won't necessarily give you an indication of that. Best Keith - Original Message - From: Michael Allen [EMAIL PROTECTED] Subject: Re: [biofuels-biz] skin on biodiesel Thanks Paul, I'll try to follow that up. Currently in Thailand, we wash the BD made from stearin with almost indecent haste. Of course, if the skin comes from near the BD/glycerol interface, we should suspect methanol evaporating from the glycerol. So is the skin on the top of the BD or really on top of the glycerol? Others participants have already raised the matter of 1) whether it is BD soluble or 2) water soluble 3) Affected by separation time, 4) Disappears in the wash. Are we sure we are all talking about the same skin Thanks again Paul - there is nothing like a few facts to muck up a perfectly good theory! : - ) Michael Allen Michael, building new processor . At the moment I make BD in 10l batches in 15L plastic drums hand shaken. The mix is poured into 20L plastic pails where it is stirred intermittently over a period of an hour. The settling time for the glycerine reduces with each stir. As the drums are filled a thin skim/film forms on the surface of the BD. This film readily redissolves. (perhaps its polimerisation under the influence of the air ). The only problems I have had with the BD/glycerine interface is when using high levels of alkali (above titration levels) in the single stage alkali process. I like to drain the glycerine as soon as possible as extended contact of BD/alkaline glycerine tends to form a jelly like material at the interface which makes washing very difficult (emulsification). As long as the glycerine is drained off early, have found that higher than titration levels of alkali give easier washing. Prefer to use higher than titration levels of alkali, gives lower yield volume but a Bd with lower SG and viscosities. Hope that helps, Paul Gobert. Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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: [biofuels-biz] skin on biodiesel
Paul, Is tallow biodiesel more likely to form soaps? I always assumed that skin is a sign of soaps, though I haven't made any fuel that skinned in a long time. This would be washed out. Mark At 09:39 PM 12/11/2002 +1000, you wrote: Michael, have noticed that raw biodiesel from tallow readily forms a skin as it cools, but the same BD after washing does not. Paul Gobert. Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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/ Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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: [biofuels-biz] skin on biodiesel
Lots of interesting chemistry coming out of this thread, but I do wonder whether the answer might not be in the physics rather than the chemistry of the process. Possibly the glycerol has not fully settled when the upper layers of ester are syphoned off. Then, when the lower level is exposed to cold air, the entrained glyc. solidifies into the reported skin. Why not try a longer (or warmer, with better insulation) settling period before racking off? David T. Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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: [biofuels-biz] skin on biodiesel
- Original Message - From: girl mark [EMAIL PROTECTED] Paul, Is tallow biodiesel more likely to form soaps? I always assumed that skin is a sign of soaps, though I haven't made any fuel that skinned in a long time. This would be washed out. Mark Mark, can't answer that one, have noticed skinning on BD from both veg oil and animal fat, but have not compared levels. Did notice however that the skin will redissolve if stirred back in. Skin even washes ok. Remember some time back I was posting about the thickish white layer between BD and wash water on settling after mist washing. You asked what made me think it was not emulsion. Turns out it was emulsion, a sample of it is separating to BD, smaller intermediate layer and water after standing for about a month. Origionally sampled it with intent of getting it analysed, no need now. Regards, Paul Gobert. Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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: [biofuels-biz] Skin on biodiesel
If it is mono and doglycerides you should be able to take some of the skin and reprocess it with more methoxide and produce esters. If it is soap you should not be able to do this. If it is tallow esters this test shouldn't tell you much. Mark At 03:01 PM 12/12/2002 +, you wrote: The skin will be mono/diglycerides that have not been reacted. If you work it out stoichometrically (using molar quantities from a known fatty acid profile) your yield of products should be: (Esters) minus (glycerol) minus (catalyst) minus (molar excess of MeOH). So you if have less esters than a predited (molar) yield of esters with skin forming you are therefore running sub-optimally. Diglycerides should be soluble in the ester layer, monoglycerides solubilise in water. Dave rpg wrote: - Original Message - From: girl mark [EMAIL PROTECTED] Paul, Is tallow biodiesel more likely to form soaps? I always assumed that skin is a sign of soaps, though I haven't made any fuel that skinned in a long time. This would be washed out. Mark Mark, can't answer that one, have noticed skinning on BD from both veg oil and animal fat, but have not compared levels. Did notice however that the skin will redissolve if stirred back in. Skin even washes ok. Remember some time back I was posting about the thickish white layer between BD and wash water on settling after mist washing. You asked what made me think it was not emulsion. Turns out it was emulsion, a sample of it is separating to BD, smaller intermediate layer and water after standing for about a month. Origionally sampled it with intent of getting it analysed, no need now. Regards, Paul Gobert. Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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/ -- David Preskett, BSc (Hons.), AIWSc [EMAIL PROTECTED] Reduce - reuse - recycle University of Wales BioComposites Centre Deiniol Road Bangor Gwynedd LL57 2UW http://www.bc.bangor.ac.uk Tel +44 (0)1248-370588 Fax: +44 (0)1248-370594 Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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/ Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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: [biofuels-biz] skin on biodiesel
Padraig, Thanks for the information. We have a locomotive in Thailand running 300 kilometres a day on a 50:50 blend of biodiesel:petrodiesel. The biodiesel in primarily methyl stearate because it is made from the waxy solid stearin/palmitin that separates out of the olein in the palm oil. We've even had it analysed by gel chromatography. In 1983, I had a student here in New Zealand making biodiesel from tallow (which is also primarily stearin). [Hey Keith! Perhaps I am the real Father of Biodiesel in New Zealand! Now what I need is a second-rate journalist to do my PR . . . . ] If there are any drying oils present in the oil (such as linseed, fish or flax-oil), oxidation of the relevant unsaturated fatty acids can be expected to form a polymeric film on the biodiesel/air interface. It reforms every time the surface is broken until it is all reacted with the air. I wonder if that could be an alternative explanation? Wendell, what do you think? Could there be any unreacted and unsaturated FFA present? Padraig! Glad to hear you got the paper OK! E-mail from southern Thailand was just slightly less reliable than it is from here in New Zealand. Regards Michael Allen 11/12/02 01:21:31, goat industries [EMAIL PROTECTED] wrote: Michael Allen's question: What makes you so sure it is methyl stearate? Do you have a reference for this perhaps? This conclusion is one of my own drawn through my own experiences with making biodiesel from waste oil. There is no research reference that I know of. What do you think it is? By the way, did you ever receive that paper I sent you entitled Kinetics of Palm Oil Transesterification In a Batch Reactor by D. Darnoko Munir Cheryan ? Yes thanks! I did! Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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/ Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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: [biofuels-biz] skin on biodiesel
Michael, thanx, In some research into used oil I have been perfoming, the source and use it has been put has a great bearing over the content. I noticed the supply of oil had come mainly from fish and chip shops. The oil may well contain an amount of more highly unsaturated fatty acid such as those derived from deep sea fish. The higher unsaturated nature is then capable of polymerizing, especially when there is no stearic hindrance occuring due to being held as a triglyceride. The commercial cooking oils in Australia also contain other ingredients, being polymethylsiloxane (antifoam) and antioxidant. The antioxidant is most likely destroyed due to prolonged heating and rxn with water and amines etc. Therefore when the free pufa's are exposed to air, a very rapid rxn will occur. What I don't understand is, I separate the BD using a settling tank with conical base, and skim the good material from the top and drain the glycerol from the bottom. The first 60-70% BD from the top is very good, but it is the remaining BD that develops the skin. Maybe it's the prolonged contact with the water that causes this. I'll have to locate some bromine to test the saturation level. -Original Message- From: Michael Allen [mailto:[EMAIL PROTECTED] Sent: Wednesday, December 11, 2002 7:43 PM To: biofuels-biz@yahoogroups.com Subject: Re: [biofuels-biz] skin on biodiesel Padraig, Thanks for the information. We have a locomotive in Thailand running 300 kilometres a day on a 50:50 blend of biodiesel:petrodiesel. The biodiesel in primarily methyl stearate because it is made from the waxy solid stearin/palmitin that separates out of the olein in the palm oil. We've even had it analysed by gel chromatography. In 1983, I had a student here in New Zealand making biodiesel from tallow (which is also primarily stearin). [Hey Keith! Perhaps I am the real Father of Biodiesel in New Zealand! Now what I need is a second-rate journalist to do my PR . . . . ] If there are any drying oils present in the oil (such as linseed, fish or flax-oil), oxidation of the relevant unsaturated fatty acids can be expected to form a polymeric film on the biodiesel/air interface. It reforms every time the surface is broken until it is all reacted with the air. I wonder if that could be an alternative explanation? Wendell, what do you think? Could there be any unreacted and unsaturated FFA present? Padraig! Glad to hear you got the paper OK! E-mail from southern Thailand was just slightly less reliable than it is from here in New Zealand. Regards Michael Allen 11/12/02 01:21:31, goat industries [EMAIL PROTECTED] wrote: Michael Allen's question: What makes you so sure it is methyl stearate? Do you have a reference for this perhaps? This conclusion is one of my own drawn through my own experiences with making biodiesel from waste oil. There is no research reference that I know of. What do you think it is? By the way, did you ever receive that paper I sent you entitled Kinetics of Palm Oil Transesterification In a Batch Reactor by D. Darnoko Munir Cheryan ? Yes thanks! I did! Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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/ Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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/ Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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: [biofuels-biz] skin on biodiesel
Michael, have noticed that raw biodiesel from tallow readily forms a skin as it cools, but the same BD after washing does not. Paul Gobert. Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ 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/
