|
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, the Biomass Energy Foundation
SUBJECT: Making Bio-diesel in the kitchen
Biodiesel is a new, alternative, renewable, clean diesel fuel made from Nature�s triglycerides - oils, fats, waste cooking oils and many other natural products. ,
However, if you would like to try the reaction in your kitchen, here's the recipe for a simple demonstration you can try, 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 (with the terrible names �transesterification� or �alcoholysis�3) substitutes methanol (wood alcohol) for the Glycerol 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 + Glycerol (+soap from catalyst)
The lye converts a small amount of the oil to soap so that the methanol will be soluble in the triglyceride. After the reaction is over, the glycerol and soap settle to the bottom of the vessel and the biodiesel floats on top.
In a measuring cup measure 200 ml of methanol. To this add 1 level tsp of lye (sodium hydroxide). In a separate pan, heat 500 ml (1 cup) of any vegetable oil cooking oil (such as Mazola, Canola etc.to about 120F (using a candy thermometer). Put the oil in a blender and add the methanol-lye mixture to the warm oil while vigorously stirring. Stir for 30 minutes. This solution is opaque at first, but as the reaction progresses it becomes thinner than the original oil and translucent.
Allow the mixture to settle for a day in a tall thin vessel. You will see two separate layers. The biodiesel floats to the top as a clear liquid, and can be poured off into a container for display(or into your diesel car or truck). The glycerol and some soap go to the bottom and can be discarded in this experiment. In commercial practice the glycerol and soap can be further processed to other fuels.
You have now made biodiesel on a small scale and can better appreciate the use of renewable fuels from farms.
<><><><><><><><><><><><><>
BIODIESEL FROM WASTE VEGETABLE OILS
Every fast food restaurant discards large quantities of waste vegetable oils weekly. They are collected and sold as �yellow grease� and can contain fats from cooked meat and free fatty acids from the breakdown of the oil. Yellow grease is an attractive source of biodiesel, but is more difficult to convert to biodiesel because it contains 2-10% free fatty acids (the cause of the rancid taste) which consume some of the lye catalyst.
Many people are converting �yellow grease� to biodiesel or using it directly. (See
http://en.wikipedia.org/wiki/Yellow_grease) and
http://www.easternct.edu/depts/sustainenergy/calendar/biodiesel/Geise%20-%20Biodiesel%20from20Recycled%20Vegetable%20Oil.pdf
It requires additional lye to neutralize the free fatty acids and the process so more chemistry than the kitchen provides.
|
