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In Summer, 1989, I learned about the conversion of animal fats and vegetable oils to their methyl esters for fuel purposes from some proceedings of the US Dept of Agriculture workshops held in the early 1980s and from research at the University of Idaho and others. The process is called "Transesterification", and is quite simple. It means converting the fats are oils, which are tri-esters with glycerol, to the monoester with methanol. Being interested in alternate fuels, I mulled this over in my subconscious and in November, 1989, I wondered what happened to all that good oil/fat when it was "used up". I found that there are about a billion gallons a year under the heading "yellow grease" which are used for soap, cattle feed, but has a very low value (<$1/gallon) relative to new oil/fat.
I wondered if it could be used to make the esters for fuel. I went to our local McDonalds and got a gallon of "waste grease" from their grease dumpster in back, (UGH!). In my lab at the Colorado School of Mines I made minor adjustments in the transesterification recipe and made a gallon of beautiful fuel from (UGH) grease. Wow! As a chemist I had a wonderful time for the next few months making "transesterified waste vegetable oil" from many feedstocks. Even made it from bacon grease at Christmas in my daughter in law's kitchen from grocery store components.
If you are the kind that likes contact with reality, why not make some
Bio-diesel in the kitchen . Just print out the file and GO. Be sure your fat/oil is dry. Bacon grease and butter contain too much water unless you boil it off and render them to a clear oil (ghee for butter).
At that time the DENVER RTD bus company was considering alternate bus fuels. We approached the bus company to see if they were interested in this alternative clean fuel. Sure, but they needed more than a gallon to test. I went to our UNIT OPS laboratory at the Colorado School of Mines and made 100 gallons (2 drums) for testing by
RTD.
I didn't think "transesterified waste vegetable oil" was a very good name, so, considering the source, I decided to call it McDIESEL. I applied for a copyright. I even approached McDonalds to see if they were interested. They were, but said they would sue me if I used that name. Later people came to call these fuels "BIODIESEL", and I now live with that. However, I would love to have had McDonalds sue me - what publicity!
We discovered that there was NO political base for using low cost waste grease for an alternate fuel. There was a tremendous base for spending much more money to make Biodiesel from Soy Oil. Now biodiesel is highly political and there is a newsletter telling of test results and new companies hoping for government subsidies courtesy of global warming. Check them out at
www.biodiesel.org.
In February 1990 we tested the fuel on a dynamometer and a bus and it ran fine and had low emissions. We have published a number of papers on Biodiesel from waste grease, but no one is particularly interested. Meanwhile biodiesel from soy is still $3-4/gal.
If you are interested in making some biodiesel, here is our recipe for making it in the kitchen with easily available materials:
May 20, 1997
TO: People interested in making Biodiesel
FROM: Thomas B. Reed
SUBJECT: Making Bio-diesel in the kitchen (available as PDF
file)
BIODIESEL FROM VEGETABLE OILS AND ANIMAL FATS
Thank you for your inquiry concerning making biodiesel. Biodiesel is a new, alternative, renewable, clean diesel fuel made from triglycerides (oils, fats, waste cooking oils, ....).
Making biodiesel on a large scale is a task for chemical engineers. It is a relatively simple process, but requires purification and washing to make a commercial fuel, especially if you use waste vegetable oil.
However, if you would like to try the reaction in your kitchen, here’s the recipe for a simple demonstration using common household chemicals. REMEMBER TO HANDLE ALL CHEMICALS WITH CARE! While these are common "household" chemicals, the methanol will burn with an almost invisible flame, so extinguish all fires; the lye can burn your fingers or blind you. Read the warnings on the can!
The reaction (transesterification) substitutes methanol (wood alcohol, dri-gas, ....) for the Glycerine in triglycerides (fats, oils) to make the methyl esters called biodiesel. It uses lye as a catalyst. A junior chemist might write it:
Triglyceride (fats or oils) + Methanol =====> Biodiesel + Glycerine (Lye catalyst)
The lye converts a small amount of the oil to soap. After the reaction is over, the Glycerine and soap settle to the bottom of the vessel and the biodiesel floats on top.
Measure 500 ml (1 cup) of vegetable oil (cooking oils such as Mazola, New Maid etc.) into a blender (or mixing bowl). (Most modern measuring cups show both ml and cups.) Heat the oil to 120 F (not critical) using a cooking thermometer while carrying out the next step.
In a separate cup measure 85 ml of methanol. (The easiest source of methanol is Dri-Gas, obtainable from any automotive store. Be sure to get the cheap one - contains methanol -,, not the one containing iso-propyl alcohol.) To this add 1/4 level tsp. of lye (sodium hydroxide). (Red Devil lye is carried by most grocery and hardware stores.) Stir well with a wooden spoon, crushing as needed until all the flakes disappear. (The mixture will be slightly cloudy and is called "sodium
methoxide".)
Add the methanol-lye mixture to the warm oil while vigorously stirring, using a mixer, paint stirrer (electric drill with propeller) or blender. Stir for 30 minutes. The mixture at first thickens, then becomes thinner than the original oil.
Allow the mixture to settle for a day in a tall thin vessel. The biodiesel floats to the top and can be poured off into a container for display. The glycerine and soap go to the bottom and can be discarded, (but can make a high glycerine soap). You have now made biodiesel on a small scale and can appreciate the use of renewable fuels from farms.
This clear biodiesel contains a very small amount of soap. If you want to use it in your diesel vehicle it would be of no consequence. However, if you want to make large quantities or for sale, European specifications require removal of the soap by washing or other effective means.
If you try this successfully, I’d be interested in hearing from you about your experience. Please send a picture.
BIODIESEL FROM WASTE VEGETABLE OILS
Waste vegetable oils used for cooking are an attractive source of biodiesel, but are more difficult to convert because they contain 2-10% free fatty acids (the cause of the rancid taste) and can make a big mess. First it is necessary to remove any water present in the waste oil. Heat in the oven at 220° F for an hour or until no bubbles can be seen.
It is then necessary to titrate the oil to determine how much free fatty acids they contain. To Measure Free Fatty Acid content of your oil: mix 1 ml oil with 10 ml isopropyl alcohol (available as the other dry-gas) + 2 drops phenolthalien solution (available in a hobby shop or toy store selling chemistry set supplies). Dropwise add 0.1% lye solution (1 g lye in 1 liter water) with vigorous stirring until the solution stays pink for 10 seconds. (20 drops = 1 ml) Record the milliliters of 0.1% lye solution used. For each liter of waste vegetable oil you will need one gram of granular solid lye for each ml of 0.1% lye solution used to titrate the free fatty acids, plus the 3.5 grams required as a catalyst as described above for new oil. Completely dissolve the proper amount of Lye in the methanol. This combined mixture makes the sodium
methoxide.
Add the alcohol-lye to the oil, stir VIGOROUSLY, and separate, as in instructions above for new oil .
If not, these are jobs for professional chemists and chemical engineers. If you would like to learn more, please take a course in chemical engineering at the Colorado School of Mines or your nearest technical college first.
USING TRIGLYCERIDES FOR FUEL
Unprocessed oils and fats can also be used in diesel engines, but require adjustment to the engines and driving habits. They are too thick, so do not inject well. They become solid below about 50 ° F. If the engine is started on conventional diesel and converted to heated vegetable oils after it is thoroughly warmed up, then switched back to diesel for cooling, engine life is greatly extended.
A Mr. Louis Wichinsky claims to have developed engine modifications that permit direct combustion of waste vegetable oils. If you are mechanically inclined, rather than chemically inclined you may prefer this route. Reach him at 914 434 5067; 702 873 2772
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