Much of the following step by step instructions comes from the book: From the Fryer to the Fuel Tank, How to Make Cheap, Clean Fuel from Free Vegetable Oil by Joshua Tickell from Greanteach publishing of Sarasota Florida. If you are serious about learning all the ins and outs, it is very cheap at 19.95, and very well written for details. I would highly recommend it.
Offered by Steve.
- 1000 ml of vegetable oil in a 1500 ml beaker
- 200 ml of methanol (methyl alcohol or wood alcohol*)
- 4 grams of lye** (sodium hydroxide) onto a petri dish on a gram scale (if using used oil, instead of 4 grams of lye, see step 1.5)
If using used or dirty vegetable oil, you will need to do a "titration" to determine how much extra lye is needed to neutralize the free fatty acids.
- Measure 1 gram of lye onto a petri dish on the scale.
- Measure 1000 ml of distilled water into one of the 1500 ml beakers.
- Pour 1 gram of lye into the 1000 ml of water.
- Mark the beaker lye/water solution - do not drink.
- Measure 10 ml isopropyl alcohol into a 20 ml beaker.
- Dissolve 1 ml of used oil into the isopropyl alcohol.
- Label this beaker oil/alcohol solution
- Use an eyedropper to drop one ml of lye/water into oil/alcohol solution.
- Check pH with a litmus strip.
- Repeat step 8 and 9, counting the ml of lye/water you add, until the oil/alcohol reaches a pH of between 8-9.
- Use the following equation: the number of milliliters of the lye/water mixture dropped into the oil/alcohol mixture = x. (x + 3.5) = the number of grams of lye necessary to neutralize and react one liter of hydrogenated oil.
Combine the methanol with the lye to create sodium methoxide, an extremely strong base which will dissolve skin on contact and deaden nerve endings so you don't feel it, so don't let it touch your skin.
Pour the methanol in a blender. Next take the lye and put it in the blender and blend on the lowest setting for 30 seconds or until all the lye is dissolved in the methanol. You now have sodium methoxide.
Carefully pour the vegetable oil in the blender. Blend medium to high for 15 minutes.
Pour into another 1500 ml container, if your lucky, one with a stopcock for bottom draining. Let settle for 8 hours. 75% of the settling will occur in the 1st hour. Don't drink, it's not a margarita. After 8 hours the top layer will be clear while the bottom layer will be dark with maybe a middle layer that is semi-translucent. Though the reaction occurs within the first hour, the glycerin soap must settle to the bottom, leaving the methyl esters, or biodiesel, on top.
If you have a stopcock, try and drain out just the glycerin. if you get a little biodiesel with it, it is OK. You are mainly concerned with the remaining biodiesel. If you don't have a stopcock, then do not pour, you will mix the glycerin with the biodiesel. Use either a hand pump (like a ketchup or glass cleaner bottle pump) or a water circulation pump (from a fountain or a fish tank). If you are really careful, you could use a ladle and carefully scoop it out, just make sure you don't stir or mix back in the glycerin. You're done!
If you are making larger batches, then use x+3.5 grams of lye multiplied by the number of liters of oil you are reacting. Also the big batches must mix for at least 1 hour.
If you want, you can use the thick and thin remaining glycerin as industrial quality soap. If not, the glycerin is a biodegradable waste product.
* Methonal or methyl alcohol can be made by fermenting saw dust and distilling out the methyl alcohol. See my posting on how to make alcohol for details. You can also distill windshield wiper fluid at 149F/65C. Its primary ingredient is methyl alcohol.
** Lye or sodium hydroxide (NaOH) is the active ingredient in drain cleaners. Also by electrolysis, you can mix warm water and table salt (NaCl) and a 12 volt battery putting in the electrodes at opposite end of the solution to get oxygen and chlorine gas (very poisonous, do not inhale) and sodium hydroxide solution remaining. I have also heard of using the white wood ashes from a very hot fire (oak and apple wood is best though any soap will do) and rain water, any other nondistilled water may require a little baking soda. Fill a barrel or container to about 4 inches below the top. Add enough water to the ashes to coat but not be swimming in the water. Let stand 4 or more hours (overnight). Drain the brownish water in a container for your homemade lye water. If an egg or potato will float just below 1/2 way or a chicken feather will start to dissolve in it the lye water is about right. If the egg does not float or you want a stronger solution, then boil it down.