Keith, You mentioned using mild air pressure to pump from a carboy into the top of the processor. What are you using to create the mild air pressure? I agree that if there is a possibility of evolving too much gas from the reaction, that the main processor is the place to start the mixing of an addition, but it can still be done with the inline method. The simple and safer advantages would involve just hooking up hoses and turning valves. You wouldn't be opening the container again until it was empty. Unless the inline tubing needed repaired you wouldn't be unhooking it between processes. Changing caps and fittings on containers as you put it involves opening the container and exposing yourself to hazardous chemicals. I'm not saying your method is unsafe or wrong. I just stated the advantages of an inline system. I think Angus had a good idea.
Keith Addison <[EMAIL PROTECTED]> wrote: linden duncan wrote: >>The advantage I see to using the inline or Appleseed method would >>be that once you >>prepare your addition, you would not have to touch it again. Just >>as simple and safer. I'm not quite sure what you mean - "addition" means the methoxide or acid or whatever you're adding? If so, I can't agree with you. We don't "touch it again", we never touch it at all. Did you look at our processor page? I don't think so, somehow. >http://journeytoforever.org/biodiesel_processor10.html >Journey to Forever 90-litre processor You have to change caps maybe, that's all, and you'll have to do that too with the inline method. You think that's safer and simpler? Actually, I don't think so. I don't want to argue about this, I said I'm sure either way will do, I'm not knocking the inline method at all, but I'm not going to be put in the wrong either, for the wrong reasons. These are some things Girl Mark has said about it in the past: "Use a valve on your methoxide delivery tubing so that you can time the methoxide delivery into the plumbing before the pump intake such that it matches the turnover rate of your tank so it mixes gradually and evenly." Our way is simpler than that, no timing required. And this: >Here's one other dangerous variable that most people are unaware of: > >water in oil when making biodiesel > >What's that , you say? water as a fire hazard? > >Here's how it happens: > >If you pump-mix methoxide with wet oil, there is a slight danger of >localised boiling of methanol (!!!!!) IF the ratios of methoxide to >wet oil is high. This inproper ratio only happens if your methoxide >inlet to the pump is large compared to the oil inlet, or if any >valves in the two lines (oil and methoxide) are open to the wrong >ratio (ie oil mostly closed down and methoxide wide open). For >example, a 3/4 piece of tubing for methoxide delivery going into a >pump along with a 3/4 inch oil inlet tube is what I consider a >high ratio. (I now use 3/8 inch methoxide tubing and 3/4" oil, with >a valve on the methoxide tube, which is only opened slightly) > >What happens is this: the lye in the methoxide can produce heat when >it hits water (from the oil). Normally if your ratios are correct, >we're not using enough lye (and there should'nt be enough water) to >cause this to raise the temperature in a whole tank of (even very >wet) oil. But in a pump-mix situation with incorrect tubing ratios, >there is momentarily a situation in the pump plumbing where the >oil/water quantity is low and the methanol/lye quantity is high- >which could get hot enough to surpass the boiling point of methanol >(148F/60C). If your tank isn't a closed system (and plastic conical >tanks and their 'manhole' covers are not a closed system!) then the >methanol vapors will boil out of your tank, and the tank will >pressurise (yet another reason for avoiding plastic as a mixing >tank) which means that any normally invisible leaks will spray >methanol-containing hot oil/biodiesel out of the tank. > > You may also notice a bunch of soap being made- there'll be odd >gelling if the oil/ biodiesel/methanol makes it's way out of the >tank! > >I don't think people are very aware of this problem. Pump mixing is >absolutely, hands-down superior to stirred tank mixing- and it's >far easier to build a sealed system with a pump rather than a >stirred tank- but you have to have the methoxide delivery be slow, >both for the safety reasons above and to keep the production of >soap down. I think peopel sometimes rush to mix in their methoxide >(because after that step there's no more operator involvement >needed) but there are a few good reasons to slow down methoxide >delivery- 1. preventing the overpressure situaiton above 2. not >making a bunch of soap (which happens in the above situaion because >there's too much lye for the amount of oil in the pipe) and 3. >making sure you get a very, very good initial mix of reactants, >which is easier to control in the pump ratios rather than hoping >that it'll all mix through circulation later on. not using wet oil >is of course also important. Simple and safe if you know what you're doing, eh? Did you know that? No such problems when you add it in the top - but do have a look at how it's done first this time before you argue about it, if you're going to argue about it. Anyway, just dewater the oil, you might think, no problem. Yes, in an ideal world, but that might not be so simple either. With some oils getting ALL the water out might not be too easy, or might not even be possible. But the methoxide will find it there alright, and if you haven't got your plumbng rigged right you could have problems. Best wishes Keith >Keith Addison <[EMAIL PROTECTED]> wrote: >We use mild air-pressure to pump the methoxide from the carboy into a >valve in the top of the processor, quite slowly. Maybe the way the >oil inlet from the pump to the top of the processor is arranged also >has something to do with it, but the mix is thorough and fairly >instant. On adding the sulphuric acid for the acid-base process, also >in the top, the oil-methanol mix in the pump tube (clear woven PVC) >changes colour in a second or two, and that's at less than 1 ml per >litre. It's simple and effective, I don't think feeding it (or the >methanol/methoxide) straight into the pump would achieve a more >thorough mix. I'm sure either way will do, but if feeding it straight >to the pump gets too complicated try it this way. >http://journeytoforever.org/biodiesel_processor10.html >Journey to Forever 90-litre processor > >Best wishes > >Keith > > > >Look at the processor plans at: > >http://www.journeytoforever.org/biodiesel_processor.html . The > >APpleseed reactor and many others have the type of pump-mixed system > >you're describing. The way methoxide is added, is that a second tank > >(a 5-gallon jerrican in my case) is used, which the methoxide is mixed > >up in. Then it's plumbed inline with the intake of the pump. When y0u > >add methoxide, you just open a valve, and hopefully the pump will draw > >in the methoxide into the oil stream. > > > >The other devices for this sort of thing include venturis (which would > >make this work a little better than the current APpleseed arrangement > >does) and various agricultural sprayer equipment 'injectors' for > >adding pesticides to a stream of liquid. I don't have direct > >experience with these. Venturis and other inline chemcal injection > >devices are found at the Northern Tool, tractor Supply Company, > >various local agricultural/ranch/farm supply places, www. > >surpluscenter.com, and McMaster-Carr (McMaster.com I think). > > > >Let us know what you find and how it works for you. > > > >Mark > > > >--- In biofuel@yahoogroups.com, Angus Scown <[EMAIL PROTECTED]> wrote: > > > I have just started construction of my processer. I have started > >pretty > > > simply by building a cone bottomed 44 gallon (200 litre) drum. I > >was > > > thinking of using a pump to do the mixing as it seems very simple to > > > design/install and with clear pipes in sections to monitor the > >colour. > > > > > > My construction helper (he who welds) and I got talking about the > >addition of > > > the Methanol , Acid, Methoxide. He got me thinking about some sort > >of inline > > > 'adder' so I could drip my chosen substance in to the pump mixing > >lines. > > > This would help me get a good mix. Has anyone else got experience > >with this > > > type of design. Not knowing too much about pumps etc what sort of > >device > > > could I look for/make for adding the substance 'mid flow'. > > > > > > Many thanks. > > > > > > Angus 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 SponsorADVERTISEMENT --------------------------------- 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 the Yahoo! 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