Here are some Titration 101 instructions that I wrote in response to an SVO'er asking about free fatty acids content and how to look for it. Since I was talking to someone who was NOT going to make biodiesel but was instead going to use straight vegetable oil, this was very crude and simple equipment recommendatinos. but they're fine for making your first liter batches and doing your first titration if you don't yet have better equipment. If you make biodiesel, just be careful with your mesaurements, but the equipment advice is all the same:
Tailgate Titration 101: I do a titration when I drive around looking for oil to dumpster-dive in an unfamiliar city. Or better yet, when I bike around first to scope out the oil dumpsters. That way I don' t haul home 40 gallons of high-ffa oil and find myself disappointed that it was the bad stuff. It's easier than it probably sounds, and takes about 1 minute once you have all your materials organized. I have a 'titration kit' in a small toolbox that keeps it organized. The titration is cheap no matter what you do, normally the expense is in lab glassware. Fortunately for a really crude titration you need gear that only costs a few dollars at the drug store (assuming you're in a country that calls it dollars and drug store!) get: -jug of distilled water ($1), -a can of 100% lye (Red Devil drain opener in the US, nothing like 'Liquid drano, "New improved recipe", or 'crystal foaming' nothing- has to be 100%, dry lye). you'll only use 1/510 of this can, so just beg some from your biodieseler friend if you have the choice! keep it tightly sealed. ($4.50/ a 510-gram can here) -two eyedroppers graduated in 1 milliliter fractions, or some equivalent device- a syringe, a pipette, etc.. I suggest using one eyedropper and one syringe, so that you don't mix up the one you use for oil and the one you use for your lye/water reference tester. Both eyedroppers and syringe bodies are under $2 at the 'giving medicine to babies' section of the drugstore, so don't worry, you don't have to scare the pharmacist asking for syringes that could be used for IV drugs or whatever. -a little bottle of phenol red from the pool/spa/hot tub supply store or hardware store. This is good enough for a crude rough titration. Better yet for actual biodiesel making, get phenolpthaleine, or a pH meter, or pH strips. But the phenol red is $1.50 a bottle and the phenolpthaleine or pH strips is more like $14 sometimes. Phenol red and most of the other stuff has a liimited shelf life and gives less accurate results after a while and if broken down by sunlight. Usually when it fails it first starts to give a much fainter color which is your indication to replace the bottle. Dig deep and spend another dollar fifty. -isopropyl rubbing alcohol, preferably 99% pure. It is more common in 70%, but if you look around you can find at least 91%. It'll even work with 70%, but isn't as accurate. -some way to measure 1 liter. I used a Nalgene sports drinking water bottle once, it should be easier for y'all in Metric using countries. -some way to measure 10 mililiters/ this could also be another syringe body from a drug store. -a small jam jar to use as your titration vessel -a well-labeled bottle that seals tightly to store 1 liter of lye/water reference tester in. -a way to measure 1 gram of lye accurately, just one time for making your reference tester solution. Ask your kids' science teacher... or make the Paper Cup Balance Beam (*see below) -a second little jar to dispense your lye/water into, so that you never have to dip your eyedropper into your clean liter of reference tester. tips: Any of the 1 ml or 10 ml measuring devices are much more accurate the thinner they are. So don't use your 250 ml graduated cylinder to try and measure out 10 ml. Also, don't try and draw up 1 ml only into an eyedropper and then squeeze like hell trying to get all the liquid out- it's more accurate to draw up 2 ml and then dispense out 1 ml of that. the process: First time you do this, make a reference tester by dissolving 1 gram of lye in 1 liter of water. Store tightly capped, you'll use this liter for months and don't want to contaminate it. -When you're ready to do a titration, pour out some reference tester into the lye/water jar so that you don' t have to dip into or knock over and spill the main liter of it. -Measure out 10 ml of isopropyl, and add to titration vessel (a small jar) -Measure 1 ml of oil into this titration vessel. Swirl the stuff around until the oil dissolves. It'll be harder in 70% than in 99%, and it'll be harder in cold weather than at warm temperatures. It should be milky and not have little beads of oil in the bottom of the jar. -add 2 or three drops of phenol red or phenolpthalein. The exact amount doesn' t matter. Swirl and look at color. It'll probably be yellowish. Then start adding with the second eyedropper/pipette, a few drops at a time, some of the lye/water reference tester, and keep track of how much you're putting in. You want to swirl the jar after each addition and look for a color change, and record how much reference tester it took to achieve that change. The milky yellowish color should change to lavender or something similar. If you're using pH strips, you;'re looking for pH 8.5 (the phenol red supposedly turns lavender at a range somewhere between 8 and 9something, phenolpthalein gives a more accurate result and turns pink at 8.5) tip: The phenolpthaleine is a kind of 'on-or-off' indicator in this case- you're NOT looking for a specific color of lavender, as you don't have a color chart to compare exact colors to the way you do with some pH liquid testers. you ARE looking for how much lye/water it takes to bring on the point at which the color first changes Got a result? repeat it again! till you get some sort of consistent repetition of results. Usually with the crude glassware like this, you'll make some kind of measuring mistakes. Then again, for a rough guide to your WVO it's not as crucial as for biodiesel making or deacidifying you can just wipe out the titration vessel in between titrations, no need to wash everything. So it's totally portable. It's also a good idea to label everything clearly. So what's bad oil? well, if your oil takes 3 ml or less to give the pH 8.5 result, biodieselers consider it OK. This has to do with ease of making less soapy fuel with low-ffa oil. I'm a snob and I try and get 2.5, 2, or better. If it's over 5 ml, I consider it utter crap. you can certainly use it for making biodiesel (you'll spend more money on lye and potentially have more soapiness problems), but I wouldn't want to use that stuff straight if ffa's are in fact a fuel system/engine problem. That's just my own opinion, however, and it's based on how much of a choice of better oils one has in the US at random oil dumpsters. *** Dixie Cup Balance Scale 1 ml of water weighs about 1 gram (actually distilled water at a specific temperature, but let's not get too technical here). I have made the Dixie Cup (paper cup) and drinking straw balance beam to weigh lye for making liter batches and making lye/water reference tester solution. Here's how you do it: get: - 2 identical small paper cups, such as tiny Dixie Cups. - 1 drinking straw - a needle and thread - an eyedropper or syringe graduated in ml, from your titration kit Use the needle and thread to attach one cup to each end of the straw. Then sew the thread through the exact middle of the straw, so that you can suspend the balance beam by hanging it from the thread in the middle of the straw, and it will blance 'level'. Into one side of the balance beam, put the exact number of mililiters of water, as the number of grams of lye you'd like to measure out. Use the other side to balance the lye. When it's level, the number of mililiters of water used, will equal the number of grams of lye in the other cup. mark ------------------------ Yahoo! Groups Sponsor ---------------------~--> Get A Free Psychic Reading! 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