The information on this page is based on an article "Making Biodiesel - World Famous Dr Pepper Technique (Pat Pend)"by Tilly, located at the Collaborative Biodiesel Tutorial web site, as it existed on April 16, 2006.
For basic information on what biodiesel is, see the Qué es Biodiesel link on this wiki.
Dr Pepper Technique
INTRODUCTION
The idea for the Dr Pepper Technique came about one day many years ago when Tilly was trying to figure out an inexpensive way of making a few test batches of biodiesel. The Dr Pepper method can be used to make many different sized batches of biodiesel. For this example, we are using 500ml of oil.
MATERIALS REQUIRED
* .5 litres of vegetable oil- new or used.
* NaOH or KOH (lye / caustic soda), at least 3g (for NAOH) or 5g (for KOH). This can be found in some hardware and most janitorial supply stores. It is used as a drain cleaner. NaOH and KOH can both be used, but require different ammounts.
* Methanol, at least 125ml. HEET® Gas- Line Antifreeze in the yellow bottle is methanol and readly available in most auto supply stores in the USA.
EQUIPMENT REQUIRED
* One plastic soda bottle (one or two-liter size) in good condition with top - make sure the bottle is clean and dry inside.
* Small glass jar or other container(mason jar size works well) for mixing methoxide.
* Measuring cups or beakers to measure out 120ml methanol and 500 ml oil
* Scale to measure NaOH or KOH
* Funnel
* Latex Gloves and Eye Protection
THE TECHNIQUE
CAUTION: When making Biodiesel, it's important to be safe. Because you are dealing with toxic chemicals, the potential to seriously hurt, injure, and even kill yourself and others exists. You must read and follow the safety precautions in Section 4.1 before proceeding!
OIL PREPARATION
* Measure out 500 ml of oil and put in a pan on an electric stove to heat to about 55 degC. If using waste oil, and there is water in the oil, the oil will spit and pop as it heats up. If there is a lot of water this could get very strong; if you notice this happening, try a different source of used oil that has less water or boil the water out of the oil. This is done by heating the oil past 100c and until it has stopped bubbling or craching for several minutes. Then cool the oil. Remember - Too much water in the oil will give you poor results.
*If you are using new oil from the bottle it should have no water in it, so in this case just heat the 500 ml of oil to 55 degC when you are ready to mix.
MAKING THE METHOXIDE
* WARNING:METHOXIDE IS A POISON! DO NOT BREATH VAPORS. WASH OFF ANY SPLASHES. DO NOT MIX THE METHOXIDE IN A PLASTIC SOFT DRINK BOTTLE AS THE NaOH ATTACKS THE PLASTIC AND YOU WILL QUICKLY BE SHAKING A BOTTLE FULL OF HOLES WITH METHOXIDE GOING EVERYWHERE.
* While the oil is heating mix your methanol and NaOH (lye) to form the methoxide. Use 120ml of methanol. If you are using new oil, measure 2.5g NaOH (3.5 of KOH) into a small, light container, such as a small paper cup. For used oil, you should do a titration to determine the correct amount of NaOH to use. See the Analysis y Titracion section for more information. If you do not have the materials to do a titration, try to make sure your first test is with fresh (not used) vegetable oil. Making this batch with oil from African Palm or other high FFA oils is not advised, you should read the section on Acid Esterification and Palm Oil to find out why.
* Pour the 2.5g of NaOH (3.5g of KOH) into your container. If you are using large chrystals of lye, you may want to crush them first by using the bottom side of a spoon. This will help them to dissolve more easily into the methanol. You may have to bend your cup to ensure that it pours into the opening of the plastic bottle.
* Pour the 125 ml of methanol into the bottle, using a funnel to make sure you do not spill any down the sides. Screw the top back on securely, and gently swirl the mixture to help the NaOH dissolve into the methanol. This could take a few minutes, so be patient. At first you will see the NaOH chrystals swirling in the mixture, but after a few minutes, when you stop swirling, the chrystals will be gone, and all of the NaOH will be dissolved. The container will get warm as the NaOH dissolves, since this process releases heat. Do not breath the fumes.
* You should periodically stop swirling the bottle and unscrew the top of the container just slightly to release some of the pressure that builds upduring this process. But do not breath the fumes that come out.
MAKING THE BIODIESEL
* While you are mixing the NaOH and methanol, you should be occasionally checking the oil as it is heating. Turn off the stove once the oil gets to 55 degress centigrade. If it gets much hotter than that, let it cool first before adding to your bottle. When the oil is at the correct temperature, use a funnel and pour the 500 ml of oil into the plastic bottle containing the mixture of methanol/NaOH (commonly called methoxide), then screw the top down TIGHT onto the bottle.
* Shake vigerously for about five minutes. It helps to have some friends do this with you, to share in the shaking. NO appreciable pressure is generated during this mixing. As you are shaking, you should notice the oil change from a milky appearance to a darker, but more clear appearance.
* Within about 10-20 minutes or so the by-product (commonly refered to as glycerine on this forum) starts to settle out and form an increasing layer on the bottom of the bottle. As the glycerin continues to settle, you should see a clear separation of layers start to form, with the darker glycering on the bottom, and the lighter, clearer biodiesel on the top.
* Within an hour, most of the glycerine will be settled out. You should now have a bottle containing lighter coloured biodiesel on top of a layer of darker glycerine. The biodiesel may still will be very cloudy, and it will take a day or two more for it to begn to clear. The biodiesel layer will continue to get more and more clear over the next few weeks.
And that is all there is to it. Only a little magic is involved!
I have Up-Sized the Dr Pepper technique by using a 20 litre plastic drum (longish and skinny) and make 14 litre batches. I simply lay the drum on a wooden "cradle" and place the center of the cradle on a pipe and rock back and forth for 3 or 4 minutes.
I then decant the mixture into a "finishing" container and so am ready to process another 14 litres straight away.
Now that you have a Litre of Finest biodiesel you will probably wish to wash it and this is quite easily accomplished using the World Famous Dr Pepper Wash Technique (Pat Pend)
Collaborative Biodiesel Tutorial - © Copyright 2005 All Rights Reserved
Comments (0)
You don't have permission to comment on this page.