How to Make Biodiesel From Fry Oil

Biodiesel is a great fuel that burns much cleaner than the petroleum diesel products on the commercial market. It's also something you can make at home out of waste cooking oil if you have the time and resources. In the beginning it might cost you a little more, but after you've persevered through experimenting and developing a system, you'll see a difference.

Instructions

Difficulty: Moderate

Things You’ll Need:

• 1 gm lye
• Metric scale
• 1 L distilled water
• 2 large beakers
• 1 ml waste oil
• 10 ml isopropyl alcohol
• Graduated cylinder
• Chopsticks
• Phenolphthalein solution
• Pipette
• 200 ml methanol
• Half-liter white high density polyethylene (also know as HDPE) container
• 2 funnels
• Cooking pot
• Thermometer
• Blender
• 5 clean 2-liter soda bottles
• Small siphon hose
• Duct tape

Titrate Your Waste Cooking Oil

1. Measure out 1 gm of lye on the metric scale, and add it to 1 L of distilled water in one of the beakers. You can make your own lye from the eHow tutorial explaining it.
2. Dissolve 1 ml of the waste oil into 10 ml of isopropyl alcohol in the other beaker. Use a graduated cylinder to measure it. Warm the outside of the beaker in a hot water bath and stir the oil and alcohol with chopsticks until the mixture becomes clear. Add 2 drops of phenolphthalein solution.
3. Use the pipette to add the lye solution by individual drops to the oil and alcohol until the mixture turns dark pink and remains that way for 15 seconds. Write down the number of milliliters of lye solution you added. Add the number of milliliters of lye solution to 3.5. The result is how many grams of lye you need to add to each liter of waste oil from this batch.

Make Biodiesel Fuel

4. Pour 200 ml of methanol into the HDPE container with a funnel. Put the lid back on the container of methanol and use the other funnel to add the amount of lye you figured out at the end of the titration. Replace the stopper and cap on the HDPE and swirl the mixture in the container. Swirl it until all the lye has dissolved. Once the liquid in the container is clear you're ready to proceed.
5. Preheat the oil to 130 degrees F and put it in your blender. Add the solution from the HDPE container. Turn the blender on and mix for 20 to 30 minutes. Pour the whole mixture into a clean soda bottle, put the lid back on and let it settle for 12 to 24 hours.
6. Siphon the top layer into a fresh soda bottle. Leave the darker layer on the bottom alone. If you disturb it, let the mixture settle again. Add 150 ml water to 150ml of the biodiesel in a third bottle, put the cap back on and shake the bottle violently. It should separate after one-half hour with all of the biodiesel on top and all of the water underneath. If it doesn't, try adjusting the mix time in the blender on the next batch of biodiesel.
7. Fill a fourth soda bottle three-quarters of the way with biodiesel and the rest of the way with tap water. Poke a hole in one of the feet on the bottle and cover the hole with duct tape. Turn the bottle on its side and roll it back and forth with your hands until it's mixed completely. Let it separate like in the test in Step 3. Drain the water out of the hole, but not the biodiesel. Pour the biodiesel into the last soda bottle and repeat this step three times.
8. Let the cloudy biodiesel clear for up to a few days until it's completely translucent.

Tips & Warnings

• Follow the process to make a small amount of biodiesel out of unused vegetable oil before you try it with waste oil. This way you can be sure you understand the process before you take on a 55-gallon drum of waste oil.
• The measurements for the lye and the tutorial for making the lye are for a sodium-based lye. You can use a potassium-based lye instead, but it requires different measurements and a different titration process. Don't try it with these instructions.
• If you're not sure why your biodiesel hasn't passed the quality test with the water, try adding 25ml of your biodiesel to 225ml of methanol. See if the biodiesel dissolves completely or if there's undissolved substance on the bottom of the beaker. The impurities are a result of the reaction not being finished, and the reason the water test hasn't succeeded.
• You can always run the titration test again and reprocess your biodiesel if you haven't gotten it right yet. Don't worry about waste.