In a glass container, add a gram of lye to one liter of distilled water. This is a 0. Wear eye protection and rubber gloves at all times, handle in a well-ventilated space, and be sure to label your lye and 0.
If lye gets onto your skin, neutralize it immediately with vinegar, and rinse with cool water. If you order from a chemical supplier, you can use sodium hydroxide NaOH or potassium hydroxide KOH Use the same ratio of lye to distilled water if you want to make a larger or smaller quantity of test solution. You can store this solution with a tight lid for testing of future oil batches. Add oil to isopropyl alcohol. In a separate glass container, pour 1 ml of your filtered oil and 10 ml of isopropyl rubbing alcohol.
Warm the mixture gently by placing the container into hot water, then stir until the mixture is clear. Wooden chopsticks work well to stir the oil and alcohol. Add phenolphthalein solution. Get phenolphthalein solution from a chemical supplier to use as a pH indicator, as it visibly turns from clear to pink at a pH level of 8. Add two drops of phenolphthalein to your oil and alcohol mixture. You can use a pH meter, pH test strips, or a natural food-based pH indicator like red cabbage juice instead, but you may not get as easy-to-read or accurate indications as with phenolphthalein.
Add 0. Slowly drip your lye solution into the container with oil, alcohol, and phenolphthalein. Stir continuously. Stop adding the lye solution when your mixture achieves a pink or magenta color and holds that color for 15 seconds, indicating the correct pH level. You may need to try oil from a number of different sources to find this quality, which is ideal for beginners. Discard oil that requires a very high quantity of lye and try again with oil from a different source. Ready your main quantity of oil.
Follow reliable and safe instructions to complete the rest of the biodiesel process. Note that you will add the results of your titration test the number of milliliters of lye needed to turn your mixture pink to the quantity of lye your biodiesel instructions call for. Can we use any other alcohol such as ethanol or isopropyl to make biodiesel? You are using the alcohol to titrate, or test the acidity of the oil, not to make the biodiesel.
Other types of alcohol are acceptable for this purpose, though less available. Not Helpful 11 Helpful Animal fat will ruin the process of the cooking oil, and animal fat doesn't burn as well as you'd think. Not Helpful 2 Helpful 6. Andrew Mckenna. The methanol and isopropyl alcohol will catch fire.
Methanol is highly flammable liquid. It's best to mix your methanol and lye in a well ventilated area outdoors. Not Helpful 3 Helpful 8. It recycles the cooking oil, thus preventing concentration of it in landfills. It is a better-performing fuel in the diesel engine higher 'cetayne' value. Not Helpful 0 Helpful 2. There are risks to the fuel system. Unlike traditional diesel fuel, biodiesel acts as a corrosive agent, etching into raw metal throughout the fuel system, including the fuel tank.
The resulting rust can cause problems necessitating the replacement of the fuel system. Both are toxic. Please read the warning labels on the containers for these products. Methanol is readily absorbed through your skin, so do not get it on your hands. Sodium hydroxide is caustic and will give you a chemical burn. Prepare your biodiesel in a well-ventilated area. If you spill either chemical on your skin, rinse it off immediately with water.
Normally, you can use pure biodiesel or a mixture of biodiesel and petroleum diesel as a fuel in any unmodified diesel engine. There are two situations in which you definitely should mix biodiesel with petroleum-based diesel:. You probably don't stop to think about it, but all fuels have a shelf life that depends on their chemical composition and storage conditions. The chemical stability of biodiesel depends on the oil from which it was derived. Biodiesel from oils that naturally contain the antioxidant tocopherol or vitamin E e.
According to Jobwerx. Temperature also affects fuel stability in that excessive temperatures may denature the fuel. You still can use it however, but you must make sure to perform the blank titration up until it begins to turn a light magenta before starting the titration process. If your IPA is good, you will not need to perform this step again unless the IPA has been stored for a long period of time or you suspect contamination.
Use a 10 ml syringe to measure out 10 ml of IPA. Put the 10 ml of IPA into a small beaker, 50 ml beakers work the best. Measure out exactly 1 ml of your WVO sample using a 1 ml syringe which is accurate to at least a 10th of a ml, preferably accurate to a th of a ml. Swirl it around a little by moving the beaker to ensure it dissolves completely into the IPA. It could be a white cloudy mixture or almost clear.
There are two methods for measuring the titration process. Using a pocket scale accurate to at least a tenth of a gram is the best way. Place the beaker onto the scale and tare the weight.
After the titration, you can place the beaker back onto the scale to see how many grams of catalyst solution you have added. The other method is to use syringes. If you have a magnetic stirrer, this is a great time to use it. Use the stirrer to gently stir the mixture in the beaker, or if one is not available, gently stir the mixture with a stirring rod or by swirling it with movement of the beaker.
It will usually turn a cloudy white color and then begin to show signs of pink. Once you have achieved this result, you are ready to measure your results and calculate the titration amounts. Count how many grams or ml for syringes of catalyst solution it took to complete your titration. If you are using sodium hydroxide, the base catalyst needed is 5 grams.
Divide the base catalyst by 0. As you can see, it doesn't really matter much with NaOH but it's a good practice. Be sure to only factor purity into the base catalyst.
If you're using the same catalyst in your catalyst solution, purity corrections have already been made within the mixture itself. For potassium hydroxide, the base catalyst is 7 g. Methanol, like the catalysts, also absorbs moisture from the air. Be sure that when working with methanol, to work quickly and seal the containers in between uses as soon as possible. The less moisture you have in your process, the less soaps you'll end up with in the finished product.
Once the methanol has been measured out, the catalyst now needs to be mixed into a solution with the methanol. The reaction between methanol and the catalyst is exothermic. It will release a large amount of heat during the reaction.
In the case of plastic tanks used in processors, the amount of heat released is usually not enough to make the methanol boil off, but it is good practice to add half first, let some heat bleed off and then add the rest if a lot of catalyst is needed. NaOH releases more heat in the dissolving into methanol. KOH tends to be a lot cooler when dissolving into the methanol and can usually be mixed immediately and be ready to go in minutes.
For small amounts of mixtures of methanol and catalyst, it can be mixed together quite easily by putting the methanol and catalyst into a sealed container and then shaking and swirling it around. The drill can be run for only about a minute and there should be enough agitation to fully dissolve the catalyst into the methanol.
Since methanol is flammable and drills can spark, this shaft should be attached through the cover to the tank as a permanent attachment. We have ours installed with ball bearings inside of the cover for an easy spin. Another method would be to use a pump, drawing the methanol from the bottom of the tank to the top of the container, with a screen blocking the catalyst from flowing through the bottom until dissolved.
Some processors use the mixing pump for the biodiesel reaction to perform the methanol mixing task by the switching of a few ball valves. For first-time users, it is best to do a few test batches first to be sure that measurements are being made correctly and to see how the process works. If a new brewer jumps right to the processor, lack of experience can lead to a processor full of badly reacted biodiesel and a lot of headaches.
On a small-scale, accuracy in weights and volumes of the vegetable oil and catalyst is key, so if a user can master using the right amounts for a small batch, larger batches can easily be made since there is more room for error in a large batch.
First-time users should start with fresh oil so the reaction alone can be familiarized with, and then move onto waste vegetable oil to practice processing successfully with a titration involved.
If you change your type of process at any time, such as changing from naoh to KOH or even changing to a different oil from a different restaurant, it is best to perform a test batch before a larger batch. For a small batch of biodiesel test batch usually a cheap blender is an easy way to perform the mixing process. Be careful not to use just any plastic like a water bottle as the mixture is corrosive and is likely to eat the bottle away. Keep the container closed while mixing, it can be shook vigorously and the cap partially unscrewed in between shakes to release the pressure from the gases created in the reaction.
They are toxic! Once the catalyst has been fully dissolved into the methanol, you are ready for the reaction. A magnetic stirrer would be ideal for the mixing process, however, most people starting out will probably want to use an old blender. It's best if the blender is made of glass and not plastic. Plastic ones are usually cheap and may crack under the chemical mixes and heat. Pour the oil carefully into the blender, cover with the cover and then start the mixing on a low speed while holding down on the cover.
Cover the blender again and turn on to a higher speed. Agitation in a blender is plenty enough for making biodiesel. You should only need to run it for about minutes. Once the mixing is completed, stop the blender and pour the mixture into another container, preferably clear HDPE for watching the glycerin by-product drop out. The regular rubber gaskets will deteriorate over time when exposed to biodiesel.
You can expect the blender to only last for a few test batches and to never be used again for anything else. Whichever mixing method you use, after about an hour, most of the glycerin will drop out of your product and settle to the bottom. You should wait at least 12 hours before washing it, preferably 24 hours. The longer you wait, the more glycerin will drop out and the easier the wash will be. Some users will wait weeks to let all impurities drop out, and then the water wash will be perfect and clean.
Washing is the most difficult part of the biodiesel process. It is extremely important to wash out all of the impurities left over in biodiesel that do not drop out with the glycerin. This includes soaps, salts and other such non-filter friendly contaminants. Water washing is the simplest method for washing biodiesel but can be the most difficult to perform successfully especially with heavily contaminated batches. There are some dry washing methods available which are much more convenient and effective than water washing.
The best dry wash method is the use of ion-exchange resin such as Dudalite in a dry wash tower. Another available dry wash media is Magnesol. To water wash your test batch, drain off the glycerin from the bottom. Even if there is a drain, it will not be convenient like in a larger batch.
You will be likely to end up draining out half of the biodiesel before you can get all of the glycerin out of the bottom. What I do is pour the top part the biodiesel into another container and then pour the bottom part mostly glycerin but still some biodiesel into one of our tri-pour beakers.
Once resettled in the beaker, almost all of the biodiesel can be poured into the container, leaving all of the glycerin set aside in the beaker. Now, turn the bottom upside down and let the water settle down to the top, which is now the bottom upside down. And continue to do this over and over until the water becomes very murky.
Be careful not to agitate the biodiesel too much, or you will have to wait a long time for it to separate, possibly up to a week or longer. After the water is dirty, it has captured a lot of the excess methanol, soaps and other contaminates in the biodiesel. Let it settle for a good amount of time so that you have all biodiesel on the top. Each time you wash, the water should start to become less and less murky.
As the biodiesel gets cleaner, you will also notice that you can be a little more vigorous in the washing. The goal is to get to a point where the water no longer gets cloudy at all and remains clear. This happens when the biodiesel has been washed completely.
The wash water should be at a neutral ph of 7 when the biodiesel is completely washed. Although properly washed, biodiesel will not appear fully clear until it has been dried of all of the water. The easiest but longest way is to set the container out into the sun so the water can slowly evaporate out.
It can take up to 3 weeks for this process to be complete. To speed up drying for small test batches, you can pour the biodiesel into a pot and gently heat it up to degrees. Above its boiling temperature, water cannot exist in liquid form. When the final biodiesel product has been fully dried, it will be a nice clear or almost translucent color. This is your finished product, ready to be filtered and filled to your fuel tank for use.
Once you have mastered 1 liter test batches of biodiesel, it will be time to start thinking more about the processor than the process. It is most common for biodiesel makers to use conical bottom shaped tanks for the purpose of easy draining and separation of by-products from the biodiesel. The most common set-up is to attach a valve to the bottom drain which leads to some plumbing going to a circulation pump and also to another drain which can be used to actually drain off the bottom.
I find it best to attach that drain to a hose so that by-products and biodiesel can be drained to any container. Some people even attach a 2nd pump for pumping the finished biodiesel out of the tank.
The 1st pump should be plumbed in so that it can take biodiesel and anything mixed in with it such as biodiesel and pump it up to the top of the tank. This is the best mixing method of the processor. Circulate the batch from the bottom and back to the top in a continuous loop. It is often a common practice to install temperature gauges or thermostats into this part of the plumbing as well as a water heating element for temperature control.
We install plate heat exchangers into this part of the line so we can use the hot water coming from our solar water heater. We are all about being green and efficient, and if you want to truly be green, i highly suggest adopting solar water heaters into your process. Not only will it save you a lot of energy on biodiesel making and drying, but it will also take away from your energy bill when it comes to using hot water elsewhere in your home.
A ball valve should also be installed on the drain of the methanol-catalyst solution tank so that the methanol can mix evenly with the catalyst prior to dispensing it. Mixing the methanol-catalyst solution can be tricky. Amazingly, it will only take less than a minute for KOH to dissolve into methanol with this set-up, if even that long.
You should also attach a fine screen on the top of the drain of the tank to prevent the catalyst from falling into the plumbing. Most standard processors have a 60 gallon mixing tank with a 15 gallon tank for mixing methanol-catalyst solution Other sizes could be an 85 gallon tank with maybe a 15 gallon methanol-catalyst solution tank or a gallon tank with a 30 gallon methanol-catalyst solution tank.
Stainless steel is the absolute best metal to use and regular steel, galvanized steel and especially copper and aluminum should be avoided since they will corrode quickly and affect the quality of the process. Regular rubber hoses cannot be used. Biodiesel quickly degrades the quality of rubber and rubber hoses would need to be replaced often. Clear vinyl hose tends to be the hose of choice since it holds up against biodiesel for quite some time and you can see the fluid inside of it.
This is especially great for the drain hoses. Fluoroelastomer hose will last the longest when exposed to biodiesel and processing biodiesel, however, it is not so good when up against the pure methanol-catalyst solution since methanol degrades grade a Fluoroelastomer hose.
It is extremely important to make sure there is no water in your vegetable oil before processing. Depending on how often you need to process biodiesel, you may need a few settling tanks for removal of water. Settling is the easiest way to remove water. If vegetable oil is left in a cone tank for weeks and left untouched, all of the water can be drained out the bottom readily. After the initial hours of maintaining heat, the vegetable oil should be completely separated after 12 hours, preferably 24 hours.
No matter how powerful your pump is, you will not achieve as much agitation as in a blender or magnetic stirrer. During transesterification, glycerin is removed to make the oil thinner, reducing viscosity. To make biodiesel, the esters in the vegetable oil are separated from the glycerin. The glycerin is replaced with an alcohol like ethanol or methanol. Methanol is preferred because it produces a more stable reaction.
Each of the three esters attaches to an alcohol creating three alkyl ester molecules. A catalyst is required to break the triglyceride molecule.
Either sodium hydroxide, also known as lye, or potassium hydroxide can be used as a catalyst. After the esters are free, the catalyst will combine with the glycerin, which settles at the bottom of the container, eventually creating a soap.
The amount of catalyst used in this reaction depends of the pH of the vegetable oil, which is acidic and sometimes called a fatty acid. Used vegetable oil is more acidic than new vegetable oil because it has been heated or fried, becoming hydrogenated if in the presence of hydrogen. Free fatty acids can be created when frying oil and will attach to bases, so it is important to eliminate them by adding more catalyst.
Lye makes up 0. If the vegetable oil is not new, the amount of catalyst lye may vary and a titration must be performed to know the exact amount. Dissolve one milliliter of used vegetable oil into 10 ml of isopropyl alcohol rubbing alcohol. Check the pH of this new mixture with litmus paper.
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