Re: How to make home bio fuel using cooking oil


"aquila the sisiw" <bernardsongco@xxxxxxxxx> wrote in message
news:1152973293.360344.90060@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
| project for tanso or other experimentalists
|
| Anybody can make biodiesel. It's easy, you can make it in your kitchen
| -- and it's BETTER than the petro-diesel fuel the big oil companies
| sell you. Your diesel motor will run better and last longer on your
| home-made fuel, and it's much cleaner -- better for the environment and
| better for health. If you make it from used cooking oil it's not only
| cheap but you'll be recycling a troublesome waste product. Best of all
| is the GREAT feeling of freedom, independence and empowerment it will
| give you. Here's how to do it -- everything you need to know.
|
| Three choices
| 1. Mixing it
| 2. Straight vegetable oil
| 3. Biodiesel or SVO?
| Three choices
| There are at least three ways to run a diesel engine on biofuel using
| vegetable oils, animal fats or both. All three are used with both fresh
| and used oils.
|
| Use the oil just as it is -- usually called SVO fuel (straight
| vegetable oil);
| Mix it with kerosene (paraffin) or petroleum diesel fuel, or with
| biodiesel, or blend it with a solvent, or with gasoline;
| Convert it to biodiesel.
| The first two methods sound easiest, but, as so often in life, it's not
| quite that simple.
|
| 1. Mixing it
| Vegetable oil is much more viscous (thicker) than either petro-diesel
| or biodiesel. The purpose of mixing it or blending it with other fuels
| is to lower the viscosity to make it thinner so that it flows more
| freely through the fuel system into the combustion chamber.
|
| If you're mixing veg-oil with petroleum diesel or kerosene (same as #1
| diesel) you're still using fossil-fuel -- cleaner than most, but still
| not clean enough, many would say. Still, for every gallon of vegetable
| oil you use, that's one gallon of fossil-fuel saved, and that much less
| climate-changing carbon in the atmosphere.
|
| People use various mixes, ranging from 10% vegetable oil and 90%
| petro-diesel to 90% vegetable oil and 10% petro-diesel. Some people
| just use it that way, start up and go, without pre-heating it (which
| makes veg-oil much thinner), or even use pure vegetable oil without
| pre-heating it, which would make it much thinner.
|
| You might get away with it with an older Mercedes 5-cylinder IDI
| diesel, which is a very tough and tolerant motor -- it won't like it
| but you probably won't kill it. Otherwise, it's not wise.
|
| To do it properly you'll need what amounts to an SVO system with fuel
| pre-heating anyway, preferably using pure petro-diesel or biodiesel for
| starts and stops. (See next.) In which case there's no need for the
| mixes.
|
| Blends with various solvents and/or with unleaded gasoline are
| "experimental at best", little or nothing is known about their effects
| on the combustion characteristics of the fuel or their long-term
| effects on the engine.
|
| Higher viscosity is not the only problem with using vegetable oil as
| fuel. Veg-oil has different chemical properties and combustion
| characteristics from the petroleum diesel fuel for which diesel engines
| and their fuel systems are designed. Diesel engines are high-tech
| machines with very precise fuel requirements, especially the more
| modern, cleaner-burning diesels (see The TDI-SVO controversy). They're
| tough but they'll only take so much abuse.
|
| There's no guarantee of it, but using a blend of up to 20% veg-oil of
| good quality is said to be safe enough for older diesels, especially in
| summer. Otherwise using veg-oil fuel needs either a professional SVO
| solution or biodiesel.
|
| Mixes and blends are generally a poor compromise. But mixes do have an
| advantage in cold weather. As with biodiesel, some kerosene or
| winterised petro-diesel fuel mixed with straight vegetable oil lowers
| the temperature at which it starts to gel. (See Using biodiesel in
| winter)
|
| More about fuel mixing and blends.
|
| 2. Straight vegetable oil
| Straight vegetable oil fuel (SVO) systems can be a clean, effective and
| economical option.
|
| Unlike biodiesel, with SVO you have to modify the engine. The best way
| is to fit a professional single-tank SVO system with replacement
| injectors and glowplugs optimised for veg-oil, as well as fuel heating.
| With the German Elsbett single-tank SVO system for instance you can use
| petro-diesel, biodiesel or SVO, in any combination. Just start up and
| go, stop and switch off, like any other car. Journey to Forever's
| Toyota TownAce van uses an Elsbett single-tank system. More
|
| There are also two-tank SVO systems which pre-heat the oil to make it
| thinner. You have to start the engine on ordinary petroleum diesel or
| biodiesel in one tank and then switch to SVO in the other tank when the
| veg-oil is hot enough, and switch back to petro- or biodiesel before
| you stop the engine, or you'll coke up the injectors.
|
| More information on straight vegetable oil systems here.
|
| 3. Biodiesel or SVO?
| Biodiesel has some clear advantages over SVO: it works in any diesel,
| without any conversion or modifications to the engine or the fuel
| system -- just put it in and go. It also has better cold-weather
| properties than SVO (but not as good as petro-diesel -- see Using
| biodiesel in winter). Unlike SVO, it's backed by many long-term tests
| in many countries, including millions of miles on the road.
|
| Biodiesel is a clean, safe, ready-to-use, alternative fuel, whereas
| it's fair to say that many SVO systems are still experimental and need
| further development.
|
| On the other hand, biodiesel can be more expensive, depending how much
| you make, what you make it from and whether you're comparing it with
| new oil or used oil (and depending on where you live). And unlike SVO,
| it has to be processed first.
|
| But the large and rapidly growing worldwide band of homebrewers don't
| mind -- they make a supply every week or once a month and soon get used
| to it. Many have been doing it for years.
|
| Anyway you have to process SVO too, especially WVO (waste vegetable
| oil, used, cooked), which many people with SVO systems use because it's
| cheap or free for the taking. With WVO food particles and impurities
| and water must be removed, and it probably should be deacidified too.
|
| Biodieselers say, "If I'm going to have to do all that I might as well
| make biodiesel instead." But SVO types scoff at that -- it's much less
| processing than making biodiesel, they say.
|
|
| If you want to make it yourself, there are several good recipes
| available for making high-quality biodiesel, and they say what we also
| say: some of these chemicals are dangerous, take full safety
| precautions, and if you burn/maim/blind/kill yourself or anyone else,
| that will make us very sad, but not liable -- we don't recommend
| anything, it's nobody's responsibility but your own.
|
|
| Where do I start?
| Start with the process, NOT with the processor. The processor comes
| later.
|
| Start with the new fresh oil, NOT with waste vegetable oil (WVO), that
| also comes later.
|
| Start by making a test batch of biodiesel in a blender using 1 litre of
| fresh new oil. If you don't have a spare blender, either get a cheap
| second-hand one, or, better, make a simple Test-batch mini-processor.
|
| Keep going, step by step. Study everything on this page and the next
| page and at the links in the text. There are checks and tests along the
| way so you won't go wrong.
|
| Go on, do it! Thousands and thousands of others have done it, so can
| you. Get some methanol, some lye and some new oil at the supermarket
| and go ahead -- it's a real thrill!
|
| Here's the recipe. Or just keep reading, you'll get to the recipe in a
| minute anyway.
|
| What's next?
| Learn, one step at a time. It's all quite simple really, very few
| biodiesel homebrewers are chemists or technicians, there's nothing a
| layman can't understand, and do, and do it well. But there is a lot to
| learn. You'll find everything you need to know right here. We've tried
| to make it easy for you. You start off with the simplest process that
| has the best chance of success and move on step by step in a logical
| progression, adding more advanced features as you go.
|
| "I am a pipe welder who knew nothing about chemistry but I have learned
| a lot from this website. It's set up for someone who has never had a
| chemistry class (me). If I can understand this anyone can." -- Marty,
| Biofuel mailing list, 23 Oct 2005
|
|
| "For anyone starting out or still in the R&D phase of scaling up and
| tweaking the process to improve quality, disregard anything other than
| the tried and tested directions at JtF. Print them out. Read them and
| then re-read them. Follow the instructions, don't add or subtract
| anything and you will be making quality biodiesel." -- Tom, Biofuel
| mailing list, 5 Nov 2005
|
|
| "My best advice is to follow explicitly the instructions on the J2F
| website starting from the begining and you will do just fine. In my own
| journey of discovery I learned this. You cannot afford to cut corners.
| Don't be tempted to use less than accurate measures and think that it
| will be alright. There is no cheating." -- Joe, Biofuel mailing list, 4
| Jan 2006
| This is how it works -- comment from a Biofuel list member:
|
| "Your website is very well done. I appreciate the layers of technical
| complexity. You have progressively more technical information layered
| in an escalating and logical fashion. I like the links as each new item
| is introduced, the user can click for more specific information on a
| topic and it opens in a new window. This eliminates the tediousness of
| having to constantly backtrack to where the new concept was
| introduced."
|
| The process
| Vegetable oils and animal fats are triglycerides, containing glycerine.
| The biodiesel process turns the oils and fats into esters, separating
| out the glycerine. The glycerine sinks to the bottom and the biodiesel
| floats on top and can be syphoned off.
|
| The process is called transesterification, which substitutes alcohol
| for the glycerine in a chemical reaction, using lye as a catalyst. See
| How the process works
|
| Chemicals needed
|
| The alcohol used can be either methanol, which makes methyl esters, or
| ethanol (ethyl esters). Most methanol comes from fossil fuels (though
| it can also be made from biomass, such as wood), while most ethanol is
| plant-based (though it is also made from petroleum) and you can distill
| it yourself. There is as yet no "backyard" method of producing
| methanol. But the biodiesel process using ethanol is more difficult
| than with methanol, it's not for beginners. (See Ethyl esters.)
|
| Ethanol (or ethyl alcohol, grain alcohol -- EtOH, C2H5OH) also goes by
| various other well-known names, such as whisky, vodka, gin, and so on,
| but methanol is a poison. Actually they're both poisons, it's just a
| matter of degree, methanol is more poisonous. But don't be put off --
| methanol is not dangerous if you're careful, it's easy to do this
| safely. Safety is built-in to everything you'll read here. See Safety.
| See More about methanol.
|
| Methanol is also called methyl alcohol, wood alcohol, wood naphtha,
| wood spirits, methyl hydrate (or "stove fuel"), carbinol, colonial
| spirits, Columbian spirits, Manhattan spirits, methylol, methyl
| hydroxide, hydroxymethane, monohydroxymethane, pyroxylic spirit, or
| MeOH (CH3OH or CH4O) -- all the same thing. (But, confusingly,
| "methylcarbinol" or "methyl carbinol" is used for both methanol and
| ethanol.)
|
| You can usually get methanol from bulk liquid fuels distributors; in
| the US try getting it at race tracks. With a bit of patience, most
| people in most countries manage to track down a source of methanol for
| about US$2-3 per US gallon.
|
| For small amounts, you can use "DriGas" fuel antifreeze, one type is
| methanol (eg "HEET" in the yellow container), another is isopropyl
| alcohol (isopropanol, rubbing alcohol), make sure to get the methanol
| one.
|
| Methanol is also sold in supermarkets and chain stores as "stove fuel"
| for barbecues and fondues, but check the contents -- not all "stove
| fuel" is methanol, it could also be "white gas", basically gasoline. It
| must be pure methanol or it won't work for making biodiesel. See
| Methanol suppliers
|
| Methylated spirits (denatured ethanol) doesn't work; isopropanol also
| doesn't work.
|
| The lye catalyst can be either potassium hydroxide (KOH) or sodium
| hydroxide (caustic soda, NaOH).
|
| NaOH is often easier to get and it's cheaper to use.
|
| KOH is easier to use, and it does a better job. Experienced
| biodieselers making top-quality fuel usually use KOH, and so do the
| commercial producers. (KOH can also provide potash fertiliser as a
| by-product of the biodiesel process.)
|
| With KOH, the process is the same, but you need to use 1.4 times as
| much (1.4025). (See More about lye.)
|
| You can get both KOH and NaOH from soapmakers' suppliers and from
| chemicals suppliers.
|
| NaOH is used as drain-cleaner and you can get it from hardware stores.
| It has to be pure NaOH. Shake the container to check it hasn't absorbed
| moisture and coagulated into a useless mass, and make sure to keep it
| airtight.
|
| The Red Devil-brand NaOH lye drain-cleaner previously sold in the US is
| no longer made. Don't use Drano or ZEP drain-cleaners or equivalents
| with blue or purple granules or any-coloured granules, it's only about
| half NaOH and it contains aluminium -- it won't work for biodiesel.
|
| CAUTION:
| Lye (both NaOH and KOH) is dangerous -- don't get it on your skin or in
| your eyes, don't breathe any fumes, keep the whole process away from
| food, and right away from children. Lye reacts with aluminium, tin and
| zinc. Use HDPE (High-Density Polyethylene), glass, enamel or stainless
| steel containers for methoxide. (See Identifying plastics.) See Safety
|
| See also Making lye from wood ash.
|
| Chemicals for WVO
|
| Isopropanol for titration is available from chemicals suppliers. Some
| people have used the other kind of Dri-Gas, which is isopropanol, but
| they found that it's unreliable. Best get 99% pure isopropanol from a
| chemicals supplier. 70% pure isopropanol is also said to work, but we
| found it didn't give satisfactory results.
|
| Contrary to rumour, "phenol red", sold by pool supply stores and used
| for checking water, won't work for titrating WVO, its pH range isn't
| broad enough. Use phenolphthalein indicator, specifically 1%
| phenolphthalein solution (1.0w/v%) with 95% ethanol. Phenolphthalein
| lasts about a year. It's sensitive to light, store it in a cool, dark
| place. You can get it from chemicals suppliers. See: Phenolphthalein
|
| Make your first test batch
| Here's what you need:
|
| 1 litre of new vegetable oil, whatever the supermarket sells as cooking
| oil
| 200 ml of methanol, 99+% pure
| lye catalyst -- either potassium hydroxide (KOH) or sodium hydroxide
| (NaOH)
| blender or mini-processor
| scales accurate to 0.1 grams, preferably less -- 0.01 grams is best
| measuring beakers for methanol and oil
| half-litre translucent white HDPE (#2 plastic) container with bung and
| screw-on cap
| 2 funnels to fit the HDPE container
| 2-litre PET bottle (water or soft-drinks bottle) for settling
| two 2-litre PET bottles for washing
| duct tape
| thermometer
| See Accurate measurements
|
| All equipment should be clean and dry.
|
| For methanol, you can use "DriGas" fuel antifreeze from an automotive
| store. One type of DriGas is methanol, another is isopropanol, make
| sure to get the methanol one. Also try "stove fuel" from hardware
| stores or home centres (but check the contents to make sure it's pure
| methanol, it could also be "white gas", which is gasoline and doesn't
| work), or try a chemicals supply company. See Methanol suppliers
|
| You can get lye at hardware stores, or from soapmakers' suppliers (try
| online). KOH lye works better than NaOH. "Red Devil" lye drain-cleaner
| is no longer made. Don't use Drano or ZEP drain-cleaners or equivalents
| with blue or purple granules or any-coloured granules, it's only about
| half NaOH and it contains aluminium, it won't work for biodiesel. Shake
| the container to check it hasn't absorbed moisture and coagulated into
| a useless mass, and make sure to keep it airtight.
|
| 1. Safety
|
| Read and observe the Safety instructions below.
|
| 2. Lye
|
| You need to be quick when measuring out the lye because it very rapidly
| absorbs water from the atmosphere and water interferes with the
| biodiesel reaction.
|
| Measure the lye out into a handy-sized lightweight plastic bag on the
| scales (or even do the whole thing entirely inside a big clear plastic
| bag), then close the lid of the container firmly and close the plastic
| bag, winding it up so there's not much air in it with the lye and no
| more air can get in. Have exactly the same kind of bag on the other
| side of the scale to balance the weight, or adjust the scale for the
| weight of the bag.
|
| How much to use. NaOH must be at least 96% pure, use exactly 3.5 grams.
| If you're using KOH it depends on the strength. If it's 99% pure (rare)
| use exactly 4.9 grams (4.90875). If it's 92% pure (more common) use 5.3
| grams (5.33). If it's 85% pure (also common) use 5.8 grams (5.775). Any
| strength of KOH from 85% or stronger will work.
|
| 3. Mixing the methoxide
|
| Use the "Methoxide the easy way" method -- it's also the safe way.
| Here's how to do it.
|
| Measure out 200 ml of methanol and pour it into the half-litre HDPE
| container via the funnel. Methanol also absorbs water from the
| atmosphere so do it quickly and replace the lid of the methanol
| container tightly. Don't be too frightened of methanol, if you're
| working at ordinary room temperature and you keep it at arm's length
| you won't be exposed to dangerous fumes. See More about methanol.
|
| Carefully add the lye to the HDPE container via the second funnel.
| Replace the bung and the screw on the cap tightly.
|
| Shake the container a few times -- swirl it round rather than shaking
| it up and down. The mixture gets hot from the reaction. If you swirl it
| thoroughly for a minute or so five or six times over a period of time
| the lye will completely dissolve in the methanol, forming sodium
| methoxide or potassium methoxide. As soon as the liquid is clear with
| no undissolved particles you can begin the process.
|
| The more you swirl the container the faster the lye will dissolve. With
| NaOH it can take from overnight to a few hours to as little as
| half-an-hour with lots of swirling (but don't be impatient, wait for
| ALL the lye to dissolve). Mixing KOH is much faster, it dissolves in
| the methanol more easily than NaOH and can be ready for use in 10
| minutes.
|
| 4. The process
|
|
| Using a blender. Use a spare blender you don't need or get a cheap
| secondhand one -- cheap because it might not last very long, but it
| will get you going until you build something better.
|
| Check that the blender seals are in good order. Make sure all parts of
| the blender are clean and dry and that the blender components are
| tightly fitted.
|
| Pre-heat the oil to 55 deg C (130 deg F) and pour it into the blender.
|
| With the blender still switched off, carefully pour the prepared
| methoxide from the HDPE container into the oil.
|
| Secure the blender lid tightly and switch on. Lower speeds should be
| enough. Blend for at least 20 minutes.
|
| Using a mini-processor. Follow the instructions here and improvise
| where necessary -- there are many ways of building a processor like
| this.
|
| Proceed with processing as above, maintain temperature at 55 deg C (130
| deg F), process for one hour.
|
| 4. Transfer
|
| As soon as the process is completed, pour the mixture from the blender
| or the mini-processor into the 2-litre PET bottle for settling and
| screw on the lid tightly. (As the mixture cools it will contract and
| you might have to let some more air into the bottle later.)
|
| 5. Settling
|
|
| Freshly made biodiesel, 20 minutes after processing
|
| Allow to settle for 12-24 hours.
|
| Darker-coloured glycerine by-product will collect in a distinct layer
| at the bottom of the bottle, with a clear line of separation from the
| pale liquid above, which is the biodiesel. The biodiesel varies
| somewhat in colour according to the oil used (and so does the
| by-product layer at the bottom) but usually it's pale and yellowish
| (used-oil biodiesel can be darker and more amber). The biodiesel might
| be clear or it might still be cloudy, which is not a problem. It will
| clear eventually but there's no need to wait.
|
| Carefully decant the top layer of biodiesel into a clean jar or PET
| bottle, taking care not to get any of the glycerine layer mixed up with
| the biodiesel. If you do, re-settle and try again.
|
| 6. Quality
|
| Proceed to the wash-test to check the quality. If your biodiesel
| doesn't pass the test, here's what to do next.
|
| 7. Washing
|
| If it passes the wash-test then wash the rest of the biodiesel. See
| Washing. For washing use the two 2-litre PET bottles in succession,
| with half a litre of tap water added for each of the three or four
| washes required. Pierce a small 2mm hole in the bottom corner of each
| of the two bottles and cover the hole securely with duct tape.
|
| Pour the biodiesel into one of the wash bottles. Add the half-litre of
| fresh water.
|
| a. Bubble-washing. See instructions here. Use a small aquarium air-pump
| and an air-bubbler stone -- cut the threaded lid off the wash bottles
| if necessary to get the stone in. After washing and settling, drain off
| the water from the bottom of the bottle by removing the duct tape from
| the hole. Block it again with your finger when it reaches the
| biodiesel. Transfer the biodiesel to the second wash bottle, add fresh
| water and wash again. Clean the first bottle and replace the duct tape.
| Repeat until finished.
|
| b. Stirring. See instructions here. If you have a small enough paint
| stirrer and a variable-speed drill, cut the lids off the bottles as
| above to accommodate the stirrer. Stir until oil and water are well
| mixed and appear homogenous. Settle for two hours or more, drain as
| above for bubble-washing, repeat until finished.
|
| If you don't have a stirrer, don't cut the lids off the wash bottles.
| Add the biodiesel and the water as above. Screw the cap on tightly.
| Turn the bottle on its side and roll it about with your hands until oil
| and water are well mixed and homogenous. Settle, drain as above for
| bubble-washing, repeat until finished.
|
| 8. Drying
|
| When it's clear (not colourless but translucent) it's dry and ready to
| use. It might clear quickly, or it might take a few days or up to a
| week. If you're in a hurry, heat it gently to 48 deg C (120 deg F) and
| allow to cool.
|
| 9. Congratulations! You have just made high-quality diesel fuel. Say
| goodbye to ExxonMobil & Co., you don't need them anymore.
|
| 10. Read on!
|
| Next step
|
| Our first biodiesel
| This was just an investigative project for us when we made our first
| biodiesel more than seven years ago in Hong Kong. Most of the equipment
| was rough and improvised. Apart from chemicals and some beakers,
| syringes and so on, the only thing we bought was a set of scales.
|
| We got about 60 litres of used cooking oil from Lantau Island's local
| McDonald's. There were four 16-litre cans of it, a mix of used cooking
| oil and residual beef and chicken fats. Two of the tins were
| solidified, the other two held a gloppy semi-liquid. We warmed it up a
| bit on the stove (to about 50 deg C, 122 deg F) and filtered it through
| a fine mesh filter, and then again through coffee filter papers, but it
| was quite clean -- very little food residue was left in the filters.
|
|
| Used cooking oil from McDonald's.
| We'd also bought 10 litres of the cheapest new cooking oil we could
| find -- we don't know what kind of oil it was, the tins only said
| "Cooking Oil" -- and we used this for our first experiment.
|
| It worked, though two of our first six batches failed. We've learnt a
| lot since then. Now it's easy to make high-quality biodiesel every time
| without fail. And we don't use open containers for processing now, and
| neither should you (see Safety, see Processors) -- and mix the methanol
| in closed containers too.
|
|
| Simple, safe, efficient biodiesel processors you can build cheaply and
| easily
|
| Practices, knowledge, technology, equipment and safety measures have
| all improved tremendously in the years since we brewed our first batch,
| thanks mainly to the collaborative work of thousands of biofuellers
| worldwide at the Biofuel mailing list and other Internet forums, using
| the growing body of information at our website and others.
|
| As a Biofuel list member said in 2002: "I just want to say how
| important what you all are doing here is. Closed-system fuel
| production, on a local or small regional scale, tied to local
| resources, using accessible technologies, and dependent on
| entrepreneurial innovation combined with open-source information
| exchange -- it's AWESOME. Keep up the good work everyone, before the
| planet fries."
|
| Biodiesel from new oil
|
|
| --------------------------------------------------------------------------------
|
| Make your first test-batch using one litre of new oil (fresh,
| uncooked). Follow the instructions above. Check the quality of your
| biodiesel with this basic quality test.
|
|
| --------------------------------------------------------------------------------
|
| We had difficulty finding pure methanol in Hong Kong, and eventually
| paid the very high price of US$10 per litre for 5 litres from a
| wholesale chemical supply company. It has to be 99% pure or better.
| (See Methanol suppliers)
|
| We used sodium lye drain-cleaner (NaOH, sodium hydroxide) bought in
| small plastic containers at a local hardware store, not always very
| fresh. (We recommend using potassium hydroxide, KOH, instead of NaOH.
| See More about lye.)
|
| We used 2 litres of methanol to 10 litres of vegetable oil, and 3.5
| grams of NaOH per litre of oil -- 35 grams for 10 litres. (It's better
| to start with smaller one-litre test batches.)
|
| We had to be quick measuring out the 35 grams of lye required. Lye is
| very hygroscopic, it absorbs moisture from the air; summer humidity in
| Hong Kong is usually about 80% at 30 deg C or more, and the lye rapidly
| got wet, making it less effective. (See More about lye.)
|
| We mixed the lye with the 2 litres of methanol in a strong, heatproof
| glass bottle with a narrow neck to prevent splashing. It fumed and got
| hot, and took about 15 minutes to mix. (Use closed containers for
| mixing methoxide! See above, Mixing the methoxide.
|
| This mixture is sodium methoxide, a powerful corrosive base -- take
| full safety precautions when working with sodium methoxide, have a
| source of running water handy.
|
|
| Midori checks the temperature of the oil.
| Meanwhile we'd warmed the 10 litres of new oil in a 20-litre steel oil
| drum to about 40 deg C (104 deg F) to thin it so it mixed better (55
| deg C, 131 deg F, is a better processing temperature). Don't let it get
| too hot or the methanol will evaporate. (Methanol boils at 64.7 deg C,
| 148.5 deg F.)
|
| We'd made a wooden jig with a portable vice clamped to it holding a
| power drill fitted with a paint mixer to stir the contents of the oil
| drum. This did a good job without splashing. (Not advised, it's
| dangerous to use sparking electric motors such as those in drills for
| processing with open containers. See "Simple 5-gallon processor" for a
| much better way.)
|
| Stirring well, we carefully added the sodium methoxide to the oil. The
| reaction started immediately, the mixture rapidly transforming into a
| clear, golden liquid. We kept stirring for an hour, keeping the
| temperature constant. Then we let it settle overnight.
|
| The next day we syphoned off 10 litres of biodiesel, leaving two litres
| of glycerine by-product in the bottom of the drum.
|
| Biodiesel from waste oil
| This is more appealing than using new oil, but it's also more
| complicated.
|
| First, check for water content. Used oil often has some water in it,
| and it has to be removed before processing. See Removing the water,
| below.
|
| Refined fats and oils have a Free Fatty Acid (FFA) content of less than
| 0.1%. FFAs are formed in cooking the oil, and they interfere with the
| transesterification process for making biodiesel. With waste oil you
| have to use more lye catalyst to neutralise the FFAs. The extra lye
| turns the FFAs into soap which drops out of the reaction along with the
| glycerine by-product.
|
| It's essential to titrate the oil to determine the FFA content and
| calculate how much extra lye will be required to neutralise it. This
| means determining the pH -- the acid-alkaline level (pH7 is neutral,
| lower values are increasingly acidic, higher than 7 is alkaline). An
| electronic pH meter is best, but you can also use pH test strips (or
| litmus paper), or, better than test strips, phenolphthalein solution
| (from a chemicals supplier).
|
| You can also use red cabbage juice, which changes from red in a strong
| acid, to pink, purple, blue, and finally green in a strong alkali, or
| one of the other plant-based pH indicators. See Natural test papers --
| Cabbage, Brazil, Dahlia, Elderberry, Indigo, Litmus, Rose, Rhubarb,
| Turmeric.
|
| We didn't have a pH meter when we started making biodiesel in 1999 so
| we used phenolphthalein solution. Phenolphthalein is colourless up to
| pH 8.3, then it turns pink (or rather magenta), and red at pH 10.4.
| When it's just starting to turn pink it's reading pH 8.5, which is the
| measure you want.
|
| Phenolphthalein lasts about a year. It's sensitive to light, store it
| in a cool, dark place.
|
| Don't be put of or frightened away by titration. It's not difficult,
| thousands and thousands of non-chemist biodiesel makers have learnt how
| to do it without difficulty and use it every time they make biodiesel.
| Just follow the directions, step by step. See also More about lye,
| Better titration, Joe Street's titrator, Accurate measurements.
|
| Titration
|
|
| Keith checks the pH of the waste oil.
| Dissolve 1 gm of lye in 1 litre of distilled water (0.1% w/v lye
| solution, weight-to-volume).
|
| In a smaller beaker, dissolve 1 ml of the oil in 10 ml of pure
| isopropyl alcohol. Warm the beaker gently by standing it in some hot
| water, stir until all the oil dissolves in the alcohol and turns clear.
| (Chopsticks make the best stirrers for titration.)
|
| Add 2 drops of phenolphthalein solution.
|
| Using a graduated syringe or a pipette, add 0.1% NaOH solution drop by
| drop to the oil-alcohol-phenolphthalein mixture, stirring all the time.
| It might turn a bit cloudy, keep stirring. Keep on carefully adding the
| NaOH solution until the mixture starts to turn pink (magenta) and stays
| that way for 15 seconds.
|
| Take the number of millilitres of 0.1% NaOH solution you used and add
| 3.5 (the basic amount of NaOH needed for fresh oil). This is the number
| of grams of NaOH you'll need per litre of the oil you titrated.
|
| Our first titration took 6 ml of 0.1% NaOH solution (not very good
| oil), so we used 6 + 3.5 = 9.5 grams of NaOH per litre of oil: 95 grams
| for 10 litres.
|
|
|
|
| --------------------------------------------------------------------------------
|
| NOTE: Novices should avoid poor-quality oil like this for their first
| test-batches with used oil. Find a source of oil that titrates at 2 to
| 2.5 ml of 0.1% NaOH solution, not more than 3 ml. Leave overcooked oils
| with high titration levels for later when you have more experience.
| Again, make small one-litre test batches before processing larger
| batches of WVO.
|
|
| --------------------------------------------------------------------------------
|
| Proceed as with new oil, see above: measure out the lye and mix it with
| the methanol to make sodium methoxide or potassium hydroxide -- it will
| get slightly hotter and take a little longer to mix as there's more
| NaOH this time. Make sure the NaOH is completely dissolved in the
| methanol.
|
| Carefully add the methoxide to the warmed oil while stirring, and mix
| for an hour. Settle overnight, then syphon or decant off the biodiesel.
|
| Check the quality of your biodiesel with this basic quality test.
|
| The first five times we did this, using 10 litres of waste oil each
| time, we got biodiesel (a bit darker than the new oil product) and
| glycerine three times, and twice we got jelly. The answer is to be more
| careful with the titration: do it two or three times, just to be sure.
| With poor-quality oils that have high titration levels do bracket tests
| as well. Do everything you can to improve the accuracy of your
| measurements so you get consistent results. Read on, and you'll learn
| how to make high-quality biodiesel every time, without fail. (It's a
| LONG time since we made jelly!)
|
| The production rate was less than with new oil, ending with 8-9 litres
| of biodiesel instead of 10. With care and experience the production
| rate improves.
|
| Moving on to bigger things
| When you're confident that you can get good results every time, even
| using oil from different sources, then it's time to scale up the
| process to provide your fuel needs. Now that you have a feel for the
| process and know what to expect, you'll have a much better idea of what
| sort of processor you want than if you'd started off building the
| processor (as many do) rather than learning the process first. See
| Biodiesel processors.
|
| However, one-litre test batches are not just something for beginners.
| It's a basic technique you'll always use. Many experienced biodiesel
| makers do test batches with each batch of oil. Many not only titrate
| the oil every time to calculate the right amount of lye to use, they
| also do "bracket" tests in sequence, followed by wash tests. You learn
| a lot that way, your fuel gets better, life gets easier.
|
| In fact life is already easier -- people who start off making 40-gallon
| batches often never learn the accuracy and discipline that comes from
| making one-litre test batches first. Their fuel quality suffers for it,
| and when they encounter that inevitable "problem batch", they suffer
| for it too.
|
| But if you've followed the instructions here carefully, you'll be
| familiar with all the variables, you'll have good methodology, and
| you'll be in a much better position to trouble-shoot a problem batch
| successfully.
|
| Keep a Biodiesel Journal -- make notes, keep records. Get some small
| glass jars and keep samples of all your batches, clearly labelled and
| cross-referenced to the notes in your journal. You won't regret it.
|
| When scaling up from small test-batches to a full-sized processor, be
| aware that the process will probably need some adjusting. All the
| various processing methods use averages and approximations because
| processors vary so widely. Use the fuel quality tests to fine-tune it
| to your particular processor. See Scaling up.
|
| Removing the water
| Water in the oil will interfere with the lye, especially if you use too
| much lye, and you'll end up with jelly. Test first for water content --
| heat half a litre or so of the oil in a saucepan on the stove and
| monitor the temperature with a thermometer. If there's water in it it
| will start to "snap, crackle and pop" by 50 deg C (120 deg F) or so. If
| it's still not crackling by 60 deg C (140 deg F) there's no need to
| dewater it.
|
| See Mike Pelly's recommendations: Removing the water.
|
| Here's another way, from Aleks Kac -- it uses less energy and doesn't
| risk forming more Free Fatty Acids (see below) by overheating. Heat the
| oil to 60 deg C (140 deg F), maintain the temperature for 15 minutes
| and then pour the oil into a settling tank. Let it settle for at least
| 24 hours. Make sure you never empty the settling vessel more than 90%.
|
| Here's what Biofuel mailing list member Dale Scroggins says about water
| removal:
|
| Water in vegetable oil can exist as free water, which will eventually
| settle to the bottom of a vessel; as suspended droplets, which may
| settle if the oil is heated, or the droplets are coalesced; and as
| water in solution with other impurities in the oil. Free water is the
| easiest to remove. The droplets are removed most efficiently by
| coalescing and draining. Suspended droplets that cannot be coalesced
| and water in solution are more problematic.
|
| Boiling off the water is more difficult than it appears on the surface.
| Colligative properties of solutions (and some mixtures) can make
| removal of the last traces of water almost impossible. Water mixed with
| oil will not boil at the same temperature and pressure as pure water.
| As water is removed, more heat or lower pressure will be required to
| remove more water. If the oil contains salts or semi-soluble fatty
| acids, distillation is even more difficult.
|
| As the percentage of water in the solution decreases (its molar
| fraction) its vapor pressure will continue to drop. Lowering pressure
| in the system alone may be insufficient to sustain vaporization when
| the solution becomes concentrated (the molar fraction of the solute
| greatly exceeds that of the solvent). Results will vary depending upon
| the nature of the water-soluble impurities in the oil. Few solutions
| are ideal, in terms of Raoult's law, and in used vegetable oil, there
| is no way to know what solutes are in the oil.
|
| The important thing is how well-used, or overused, the oil is.
| Titration will tell you that. The higher the titration result, the more
| water it's likely to contain, and the more difficult it will probably
| be to remove the water.
|
| Start with heating to 60 deg C and settling, as Aleks Kac recommends,
| and if that doesn't give satisfactory results, try boiling it off, as
| Mike Pelly recommends. Then try processing small test batches of a
| litre or less first. If you still have difficulties, try to find
| better-quality oil.
|
| Washing
| Biodiesel must be washed before use to remove soaps, excess methanol,
| residual lye, free glycerine and other contaminants. Some people (fewer
| and fewer of them) say washing isn't necessary, arguing that the small
| amounts of contaminants cause no engine damage.
|
| Read what the Fuel Injection Equipment (FIE) Manufacturers (Delphi,
| Stanadyne, Denso, Bosch) have to say about these contaminants:
| Summary -- html
| Full document -- Acrobat file, 104kb
|
| See also: Determining the Influence of Contaminants on Biodiesel
| Properties, Jon H. Van Gerpen et al., Iowa State University, July 31,
| 1996 -- 12,000-word report on contaminants and their effects. Acrobat
| file, 2.1Mb:
| http://www.biodiesel.org/resources/reportsdatabase/reports/gen/gen014.pdf
|
| Myth:
|
| > I did notice that a lot of the chemistry in the book was wrong.
| > His main argument seemed to be against losing the energy in
| > the methanol that was washed out.
|
| The "energy" does you no good if your particular thermodynamic cycle
| can't take advantage of it. What is the cetane rating of methanol?
| -- Ken Provost, Biofuel mailing list, "Re: washing?"
|
| Quite so. The cetane rating of methanol is only 3, very low. Low
| cetane-number fuel in a diesel causes ignition delay and makes the
| engine knock. The high-speed diesel engines in cars and trucks are
| designed to use fuels with cetane numbers of about 50. The US biodiesel
| standard specifies a cetane number higher than 47, the EU standard
| specifies higher than 51. The methanol in unwashed biodiesel doesn't
| "make a great fuel anyway". It's also very corrosive. The EU biodiesel
| standard specifies less than 0.2% methanol content.
|
| Quality biodiesel is well-washed biodiesel. Filtering it is no use, and
| letting it settle for a few weeks won't help much either. Anyway
| washing the fuel is easy.
|
| See Washing
|
| Using biodiesel
| You don't have to convert the engine to run it on biodiesel, but you
| might need to make some adjustments and you should check a few things.
|
| Petroleum diesel leaves a lot of dirt in the tank and the fuel system.
| Biodiesel is a good solvent -- it tends to free the dirt and clean it
| out. Be sure to check the fuel filters regularly at first. Start off
| with a new fuel filter.
|
| If a car has been left standing for a long time with petroleum diesel
| fuel in the tank the inside of the tank may have rusted (water content
| is a common problem with petro-diesel fuel). Biodiesel will free up the
| rust, and it could clog the particle filter inside the tank. At worst
| the car simply stops, starved of fuel. It's not a very common problem,
| but it happens. See: Biodiesel and your vehicle -- Compatability:
| Filters.
|
| A common warning is that biodiesel, especially 100% biodiesel, will rot
| any natural or butyl rubber parts in the fuel system, whether fuel
| lines or injector pump seals, and that they must first be replaced with
| resistant parts made of Viton. But rubber parts in diesel engine fuel
| systems have been rare or non-existent since the early 1980s -- it
| seldom happens, and when it does happen it's not catastrophic, you have
| plenty of warning and it's easily fixed. See: Biodiesel and your
| vehicle -- Compatability: Rubber.
|
| See Biodiesel and your vehicle
|
| Safety
| Please read this whole section right to the end.
|
| Wear proper protective gloves, apron, and eye protection and do not
| inhale any vapours. Methanol can cause blindness and death, and you
| don't even have to drink it, it's absorbed through the skin. Sodium
| hydroxide can cause severe burns and death. Together these two
| chemicals form sodium methoxide. This is an extremely caustic chemical.
|
| These are dangerous chemicals -- treat them as such! Gloves should be
| chemical-proof with cuffs that can be pulled up over long sleeves -- no
| shorts or sandals. Always have running water handy when working with
| them. The workspace must be thoroughly ventilated. No children or pets
| allowed.
|
| Organic vapor cartridge respirators are more or less useless against
| methanol vapors. Professional advice is not to use organic vapor
| cartridges for longer than a few hours maximum, or not to use them at
| all. Only a supplied-air system will do (SCBA -- Self-Contained
| Breathing Apparatus).
|
| The best advice is not to expose yourself to the fumes in the first
| place. The main danger is when the methanol is hot -- when it's cold or
| at "room temperature" it fumes very little if at all and it's easily
| avoided, just keep it at arm's length whenever you open the container.
| Don't use "open" reactors -- biodiesel processors should be closed to
| the atmosphere, with no fumes escaping. All methanol containers should
| be kept tightly closed anyway to prevent water absorption from the air.
|
| We transfer methanol from its container to the methoxide mixing
| container by pumping it, with no exposure. This is easily arranged, and
| an ordinary small aquarium air-pump will do. The methoxide is mixed
| like this -- Methoxide the easy way, which also happens to be the safe
| way. The mixture gets quite hot at first, but the container is kept
| closed and no fumes escape. When mixed, the methoxide is again pumped
| into the (closed) biodiesel processor with the aquarium air-pump --
| there's no exposure to fumes, and it's added slowly, which is optimal
| for the process and also for safety. See Adding the methoxide.
|
| Once again, making biodiesel is safe if you're careful and sensible --
| nothing about life is safe if you're not careful and sensible!
| "Sensible" also mean not over-reacting, as some people do: "I'd like to
| make biodiesel but I'm frightened of all those terrible poisons." In
| fact they're common enough household chemicals. Lye is sold in
| supermarkets and hardware stores as a drain-cleaner, there's probably a
| can of it under the sink in most households. Methanol is the main or
| only ingredient in barbecue fuel or fondue fuel, sold in supermarkets
| and chain stores as "stove fuel" and used at the dinner table. It's
| also the main ingredient in the fuel kids use in their model aero
| engines. So get it in perspective: be careful with these chemicals --
| be careful with ALL chemicals -- but there's no need to be frightened
| of them.
|

There was a recent show in "MYTHBUSTERS" where they were able to used a
filtered used cooking oil without any additive to run a Mercedes-Benz diesel
powered sedan. It ran good but they found out the fuel mileage was somewhat
less compared to a regular diesel fuel. Nonetheless, if you can get
substantial amount of used cooking oil for free or cheap, who cares about
the fuel mileage.


.