About biodiesel

The Benefits

Biodiesel can be burned in any diesel engine or home oil heater and even experimentally in gasoline engines when heavily dilluted with gasoline. Biodiesel burns cleaner than traditional petro-diesel. Since biodiesel originates from a plant instead of a dead dinosaur, we are also using the fuel in a recycling process. The plant harvests energy from the sun and CO₂ from the air using photosynthesis, which is further processed into fuel by us, then burned in an engine or heater for its energy, and CO₂ is released back into the atmosphere for another plant to breathe in and begin the process all over again. When petro-fuels are used, CO₂ is being added to the Earth system and requires extra plants to maintain current CO₂ levels in the atmosphere.

Biodiesel is more lubricating than diesel fuel. It will lubricate your injection pump and injectors, thus increasing the lifespan of your diesel engine. Biodiesel is also a good cleaning agent, so it will clean out your injectors and even your fuel tank, which is why most users will notice that they need to change their fuel filters after a couple of tank fulls when introducing biodiesel into their vehicle. your engine will perform better and eliminate the need for fuel additives commonly used in petro-diesel to enhance performance. Most users will also notice a lot less black smoking coming from their exhaust when using biodiesel and most likely, no smoke at all when B100 (100% Biodiesel) is used. The best part of all is that the exhaust smells like the oil which was used, which is a lot more of a delightful smell than the dirtier petro-fuels.

The Disadvantages

Biodiesel has about 5-10% less energy density than petroleum diesel. This will result in a slight loss in power or fuel economy. However, most users do not notice a difference at all, since this is a minimal change. Gasoline fuels mixed with 10% ethanol have exactly the same effect since ethanol has half the energy density of gasoline and most users have not noticed a difference in that either since it has been introduced as a standard into our fuel economy.

Biodiesel also has more of a gelling issue than petro-diesel. It will begin to cloud at about 40°F and gel in lower temperatures. Users of 100% biodiesel just need to mix into petro-diesel during the winter months to avoid any issues with cold starts and operation in the winter.

B100 (100% Biodiesel) will also corrode rubber lines and gaskets. Most newer vehicles already have the necessary parts for handling biodiesel, but it is best to check with the manufacturer before filling up your tank. users of B20 and less mixtures will not experience any issues with rubber fuel lines. those using B100 can experience line failure within 6 months of use, assuming the lines are new when it is started. If you should need to find a substitute for rubber fuel lines or gaskets, or if your existing fuel system requires a change, you should use Fluoroelastomer hose, which is 100% compatible with Biodiesel. The most common brand name for this type of hose is known as Viton®, and there are many generic versions of it such as our own fluoroelastomer hose which is much more cost effective and works just the same.

Introduction to making Biodiesel

Biodiesel is most commonly made from fats derived from vegetable oils. It's viscosity is similar to diesel and can run in any diesel vehicle without any modification of the engine, with the exception of old fuel lines and gaskets which may be corroded by biodiesel.

Most makers of biodiesel obtain their vegetable oil sources from restaurants. Restaurants will give away their used frying oil since it must be properly recycled and not thrown away. Aside from many other recylciing methods, biodiesel is one of the best ways to recycle this used cooking oil since it helps aid an expensive fuel market and its by-products can be used for many other things.

How Biodiesel is Produced

Biodiesel is produced by using an alcohol and a caustic catalyst such as sodium hydroxide or potassium hydroxide. Methanol is the most commonly used alcohol since it is cheap and easy to obtain. It is possible to use ethanol, but it is a more difficult process and it cannot be purchased economically for producing biodiesel due to high taxes imposed on it.

The Very Basics of Making Biodiesel

In the process, methanol and the catalyst are mixed together into a solution. The methly catalyst is then mixed with the vegetable oil for a certain period of time. Once a complete reaction is made, the methly esters will replace the free fatty acids in the vegetable oil and drop out as a glycerine by-product. After hours of settling, you're left with biodiesel on the top and glycerine on the bottom.

Differences Between NAOH and KOH

Both NAOH (Sodium Hydroxide) and KOH (Potassium Hydroxide) can be used for making biodiesel. Both catalysts are highly hygroscopic, which means they absorb moisture from the air rapidly. This will interfere with the biodiesel process if too much moisture is present.

NAOH is cheaper, more pure and less is required in the reaction. However, KOH makes a better reaction, a better by-product and is easier to use. Please refer to the table below for a specific comparisson on the advantages and disadvantages.

Simple Steps to Making Biodiesel

Step 1 - The base amount of lye catalyst needed

For clean, un-used vegetable oil, there is a base amount of catalyst which will need to be dissolved into the methanol to make a complete reaction. For NAOH, the well-accepted amount is 5 grams per 1 liter of vegetable oil. Since KOH is less dense, it's 1.4025 times as much, which is 7 grams per 1 liter of vegetable oil.

Purity must also be taken into account. Usually with NAOH, purity can be neglicted, since it is almost 100%. However, it is important to factor in purity with KOH since it is usually about 90%. To factor in purity in your calculations, divide the base catalyst amount by the % purity. We usually carry NAOH with a purity of 99.5%, which makes the calculation 5g/.995 = 5.025g of NAOH per liter of oil. For KOH, it's usually about 91%, which calculates as 7g/.91 = 7.692g of KOH per liter of oil.

When converting WVO (waste vegetable oil) to biodiesel, more catalyst is needed than for clean oil. The recipe will require the base catalyst plus an additional amount which must be determined by a titration each time a different batch of biodiesel is made.

Step 2 - Titrating waste vegetable oil (WVO)

Waste vegetable oil (WVO) containes Free fatty acids (FFA) which cause vegetable oil to be viscous and even gell at room temperature. The more FFA an oil has, the more lye catalyst you will need to replace the FFA with methyl esters.

Since FFA content increases with continued use in a fryer at a restaurant, you must perform a titration to find out the FFA content. To do this, you will need the following:

99+% Isopropyl Alcohol

1% Phenolphthalein Solution in alcohol

Accurate Syringes

Beakers or small containers to mix the solution in

1 liter (or larger) bottle

distilled water

Lye Catalyst (sodium hydroxide or potassium hydroxide)

Pocket Scale accurate to at least 0.1 grams, preferably 0.01 grams.

The process:

Create the 0.1% by weight Lye Catalyst Solution

First, you will need to make a 0.1% by weight catalyst solution in distilled water. To do this, measure out exactly 1 gram of sodium hydroxide or potassium hydroxide, depending on which catalyst you will be using in your process. Dissolve the 1 gram of catalyst into 1 liter of distilled water. For most accuracy, weigh your water rather than measuring it. 1 liter of water weighs 1 kg. For even better accuracy, increase the amount of your solution. For example, add 3 grams of catalyst into 3 liters of distilled water. Once you have a 0.1% lye catalyst solution prepared, you will be able to perform your titration.

Perform a blank titration

It is important to make sure that your isopropyl alcohol (IPA) is fresh. Since IPA does not have a ph rating, you cannot simply test it with a ph meter. But you can perform a blank titration. To do so, measure out 10 ml of IPA and place it into your beaker. Add a couple drops of phenolphthalein. Next, use a 3ml or 5 ml syring to measure out your lye catalyst solution. Put a drop or two at a time into the isopropyl alcohol. It should turn magenta almost instantly. If it takes more than a few drops to turn magenta, your IPA is bad and you should replace it. You still can use it however: just make sure to perform the blank titration up until it begins to turn a light magenta. 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.

Performing the Titration

Use a 10 ml syringe to measure out 10 ml of IPA. It is preferred to use 99+% industrial grade IPA, but amounts in 91% found at walmart will do the trick if it's not available. Put the 10 ml of IPA into a small beaker. Add a couple of drops of the phenolphthalein solution.

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 100th of a ml. Dispense the 1 ml of WVO into the beaker with the IPA. Swirl it around a little by moving the beaker to ensure it dissolves completely into the IPA. It may be cloudy.

Measure out your lye catalyst solution into a syring of your choice. It's preferable to use a 3ml syringe for sodium hydroxide and a 5 ml syringe for potassium hydroxide. If your oil is bad, you may need more.

Now swirl your solution in the beaker gently while slowly dispensing the lye catalyst solution into the beaker one drop at a time. Pay close attention to any changes in color. Each drop will at first be white, but will soon start to have a pinkish tint to it. Once a drop gets the beaker solution to remain a light magenta color for at least 30 seconds, stop adding the lye catalyst solution. You are now ready to calculate the titration results.

Calculating lye catalyst needed from titration results.

Count how many ml of lye catalyst solution it took to complete your titration. Each ml of solution required represents 1 gram of lye catalyst needed in addition to the base catalyst to process your WVO. base catalyst + ml needed to titrate = total grams needed to process the oil.

As an example:

Let's say it takes 2.3 ml of lye catalyst solution to complete your titration. If you are using sodium hydroxide, the base catalyst needed is 5 grams. So that's 5g + 2.3 g = 7.3g of sodium hydroxide per liter of oil.

For potassium hydroxide, the base catalyst is 7 g. So that's 7g + 2.3g = 9.3g per liter of oil. Don't forget that potassium hydroxide is not normally 100% pure, so you will need to factor in that purity by dividing the base catalyst by the purity. Assuming 91% purity, it would be: 7g/0.91 + 2.3g = 9.99g of koh needed per liter of oil.

3. Methanol

Methanol, like the catalysts, also absorbs moisture from the air. Be sure that when working with methanol, to work quickly and seal the containers inbetween uses as soon as possible. The less moisture you have in your process, the more success you will have.

In theory, the biodiesel process requires the amount of methanol to be about 10% of the volume of vegetable oil to be processed. This would, however, require too much time to make a full reaction, and so most users use 20% or even 22% methanol to ensure a complete and full reaction within a reasonable amount of time. The excess methanol is dropped out in the glycerine and can be recovered later through distillation.

To be clear of how much methanol to use, if you were to process 100 liters of vegetable oil, the process would require 20 liters of methanol (20%).

Once the methanol has been measured out, the catalyst now needs to be mixed into a solution with the methanol to make methoxide. For clean oil, use the base catalyst amount and for used vegetable oil, use the base catalyst + titration amount.

The reaction between methanol and the catalyst is exothermic. It will release a large amount of heat during the reaction. When NAOH is used, it's best to add half of the catalyst first, let the methoxide cool down a bit, and then add the rest later. If the methoxide gets too hot, it could boil the methanol. Another option is to mix in the NAOH without agitation and let it sit over-night. It will slowly dissolve and not heat up as much. KOH is much quicker in dissolving and does not release as much heat, so there is less danger of boiling any methanol off.

For small amounts of methoxide, it can be mixed together quite easily by putting the methanol and catalyst into a sealed container and then shaking and swirling it around. Once all of the catalyst is dissolved, it's ready. For larger applications, it's best to attach a propeller to a shaft which can connect to a power drill. The drill can be run for only about a minute and there should be enough agitation to fully dissolve the catalyst into the methanol. Another method would be to use a pump, drawing the catalyst from the bottom to the top of the container, with a screen blocking the catalyst from flowing through the bottom until dissolved.

4. The Process of a test Batch

There are a few different designs which can be used when building a processor. 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. 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. Most test batches process 1 liter of vegetable oil, which requires a standard 200 ml of methanol with 5g of naoh or 7g koh base catalyst (purity not factored in) + titration amount for used oil. First-time users should start with fresh oil, and then move onto waste vegetable oil. 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.

1 Liter Test Batches

For a small batch of biodiesel (test batch) usually a cheap blender is an easy way to perform the mixing process. Heat the 1 liter of oil up to about 150°F (65°C) using an old pot on a stove. Don't let it get any hotter or you will end up boiling your methanol when you add it.

Prepare your methoxide by mixing the methanol and required catalyst in a compatible container. Be careful not to use just any plastic like a bottle as methoxide is likely to eat it away. Stick to tough plastics such as HDPE (High density polyethylene). Keep the container closed while mixing, it can be shook vigorously and the cap partially unscrewed inbetween shakes to release the pressure from the gases created in the reaction. CAUTION: Do not breathe in these gases. They are toxic! Once the catalyst has been fully dissolved into the methanol, you are ready for the reaction.

Pour the oil carefully into the blender and then carefully add the methoxide. Put a cap on the blender and start it with a slow speed. if your blender doesn't hold much more than a liter, it may be best to add the methoxide while it's already mixing. The initial start of a blender causes a lot of turbulence in the fluid and will splash out if you do not cover it completely. I've always added the methoxide while it's already blending.

Agitation in a blender is plenty for making biodiesel. you should only need to run it for about 15-20 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. Don't leave it in the blender. 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 for anything else.

The better way to mix test batches would be to use a magnetic stirrer and a container of your choice that's compatible with biodiesel. Although they are more expensive than a cheap blender, if you plan to make more than a few test batches, it is well worth the investment. Magnetic stirrers are also very good for titrations, both for the amount of catalyst you need and soap testing.

Whichever mixing method you use, after about an hour, most of the glycerin will drop out of your product and settle to the bottom. it will be a darker color and appear much more viscous than the clearer biodiesel on the top. You should wait at least 12 hours before washing it, preferably 24 hours. The longer you wait, the more by-product will drop out and the simpler the wash will be. Basically, what is happening is the process is still occuring to small amounts that have not converted yet. In small test batches, there is usually enough agitation to not have to wait much more than 12 hours. However, in larger batches, waiting as long as possible after is a good idea to be sure you have a full reaction.

Washing a test batch

Washing is the most difficult part of the biodiesel process. Water washing is the most common method for washing biodiesel and it requires a lot of time and patience, however, both magnesol and ion-exchange resins such as DudaLite (or more commonly name-branded as Purolite® or Amberlite®) can be used much more easily. We will discuss those later.

To water wash your test batch, drain off the glycerin from the bottom. Most likely, you don't have a drain on the small container you put the biodiesel into. Even if there is a drain, it will not be convienent like in a larger batch. 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.

Next, once you have just biodiesel and NO glycerine, add 1/3 as much water as biodiesel in a slow manner so as not to agitate the biodiesel too much. the water will sink to the bottom quite readily if it's not agitated. 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 merky. 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. if you are gentle enough, it should only need about 15-30 minutes to completely settle out. Proceed to drain out the biodiesel into another container as you did before when removing the glycerin, and then add 1/3 water again and wash again. 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 virgorous in the washing. Be careful not to agitate it too much so you don't have to wait too long for it to settle. 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. usually this is achieved after 3-4 washes. The wash water should be at a neutral ph of 7 when the biodiesel is completely washed.

Drying a test batch

Although properly washed, biodiesel will not appear fully clear until it has been dried of all of the water. this can be achieved in a few different ways. 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 212 degrees. Above its boiling temperature, water cannot exist in liquid form. So once your biodiesel has passed 212°F and the bubbling has stopped, there is no need for additional heat as all of the water will have boiled off. Some people like to heat to something like 250°F to be sure, but this is a bad practice and a waste of energy since it is impossible for water to exist beyond 212°F at sea level.

When the final biodiesel product has been fully dried, it will be a nice clear or almost transluscent color. This is your finished product, ready to be filtered and filled to your fuel tank for use.

5. Processing Larger Batches of Biodiesel

Once you have mastered 1 liter test batches of biodiesel, it will be time to start thinking more about the processor than the process. Building a processor is quite simple, and you don't need all of the fancy looks of expensive processors to get the job done.

Building your own processor

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. This pump should be powerful and ideally should be able to circulate 1/3 of the tank within a minute's time. the slower the pump, the less agitation you have and the longer the processor will need to run.

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 2nd smaller tank is often plumbed in line with the 1st tank for mixing the methoxide and then slowly adding it to the process as vegetable oil is pumped from the bigger tank's bottom and back to the top. the best way to do this is to run the bottom of the methoxide tank through a small pump and down to a tee just before the circulation pump. Use a one way check valve right at the connection point to ensure that vegetable oil doesn't find its way up into your methoxide tank from the pressure created by a lot of fluid in the larger tank and gravity overpowering the circulation pump's ability to suck in both the vegetable oil and methoxide at the same time. the purpose of the methoxide pump is to help push the methoxide through that check valve to completely empty the methoxide tank. it should also be as close to the check valve as possible and preferably with a little bit of head pressure to help push it. A ball valve should also be installed on the drain of the methoxide tank so that the methanol can mix evenly with the catalyst prior to dispensing it.

Mixing the methoxide can be tricky. Since you're dealing with larger amounts of methanol, you cannot simply shake it up like in a test batch and sometimes there's too much catalyst required to just let it sit overnight and dissolve. The best solution to this, is to find a propeller like what you find on a boat motor, run it to a shaft which comes up and through the cover in the tank and is sealed off with some washers so that it's free to rotate, and then use a power drill to attach to the shaft and spin the propeller at rapid speeds. 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. This usually isn't much of a problem though if you have a ball valve, but is still recommended. be sure the propeller does not touch the screen.

Sizing your processor

the methoxide mixing tank needs to be at least 20% the size of the batches you are planning to do, and the mixing tank needs to be at least 120% the size of the batches you are doing to account for the vegetable oil and methanol added. Most standard processors have a 60 gallon mixing tank with a 15 gallon tank for mixing methoxide. Other sizes could be an 85 gallon tank with maybe a 15 gallon methoxide tank or a 110 gallon tank with a 30 gallon methoxide tank. for the 60 gallon the largest possible batch would be 45 gallons of vegetable oil and for the 85 gallon it's 65 gallons and 110 gallon would be 85 gallons. since the tanks' max capacity is based on the top most height of the tank however, it's usually best to process about 5 or 10 gallons less than these max capacities in order to avoid spillage from overflow during pumping or when there is a mismeasurement.

Materials for your processor

HDPE and other resistant to biodiesel/caustic/methanol materials should be used when building a processor. 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. PVC pipe can be used, but it's best to stick to threaded piping since glued pieces can spring leaks after awhile and cause more headache than it's worth.

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 bioidesel, however, it is not so good when up against the pure methoxide since methanol degrades grade a Fluoroelastomer hose. it is a very good idea to use vinyl hose when connecting from the methoxide tank to the plumbing of the larger mixing tank so you know when it has been fully emptied.

Moisture Removal

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 2-3 weeks and left untouched, all of the water can be drained out the bottom readily. This process can be sped up by installing a heating element at the bottom of the tank and gently heating the veggie up to and maintaining it at about 100°F to 110°F for 4-6 hours. The heat decreases the density of the vegetable oil greatly while the water's density remains about the same, settling the water down faster than normal. After the initial 4-6 hours of maintaining heat, the vegetable oil should be completely separated after 12 hours, preferably 24 hours. use the crackle test to ensure no water is present once you have removed the water just to be sure.

Processing with your own Processor

No matter how powerful your pump is, you will not achieve as much agitation as in a blender or magnetic stirrer. You could use a blender like set-up instead of a pumping system, but blades are likely to degrade when left in the biodiesel for a long period of time and it's not so easy to set such a system up. There is also a better chance of spillage when this method is used, and you won't be able to access the top of the processor very easily when you need to.

The time it takes to successfully process a large batch of biodiesel will depend on the power of your pump. Generally, it takes about 1.5 to 2 hours of circulation to fully complete the reaction. Some users need to run it for as long as 4 hours and others can get away with shorter times. Heating of the biodiesel is also very important. The temperature should be maintained at about 150°F for the entire mixing process. if lower temperatures are used, it will require longer mixing times.

Once the process has been completed, you can stop the pump and turn off the heat. let the biodiesel settle overnight just like you would with a test batch. Settling is mostly done in 12 hours, but you should wait 24 hours to be sure. the longer you wait, the better.

6. Washing larger batches

If you use a full drain tank, meaning, there is no bulk head, you will be able to fully drain your glycerin and you can potentially use your mixing tank as a wash tank. Even though this may work, it is recommended to have a separate tank from washing. if you mess up, you're stuck with waiting until your batch is fixed before you can do another, and you will need to wait for the tank to dry after using it before you can ue it on a new batch.

Assuming you transfer the biodiesel to a wash tank, drain off the glycerin into a storage container and set it aside, then transfer the biodiesel to your wash tank. there are several ways to perform a wash, and depending on which one you use will determine how you set this tank up. do not try to just pump from bottom to top like you did with the mixing, that's too much agitation and it will make a mess.

The Bubble wash method

The theory behind bubble washing is that when a bubble emerges from water at the bottom of the wash tank, the outer lining of the bubble will carry trace amounts of water up and through the biodiesel to the top of the tank, pop and then descend down slowly through the biodiesel again, pulling down with it contaminates found in the biodiesel.

To perform a bubble wash, fill the bottom of your wash tank gently with 1/3 as much water as you have biodiesel. Once settled, place an air stone attached to any air compressor used in fish tanks at the bottom and run it for about 6 hours. The many small bubbles make from the air stone will rise up and allow water to slowly and gently circulate through the biodiesel, drawing out the contaminates. after 6 hours, stop the compressor and let it settle for 12-24 hours, drain the wash water out and then add another 1/3 water and perform again until the wash water comes out clear.

Bubble washing uses the least amount of water of the water washing methods. However, if the batches are too small, it can agitate the biodiesel too much and cause an emulsion. The final clear water can be used for the first wash of your next batch and if the 2nd to last wash water was not very cloudy, it can also be re-used.

Mist-Washing Method

Mist washing is done by installing misting nozzles at the top of the wash tank and slowly introducing water through them and into the biodiesel. The fine spray of water slowly travels down through the biodiesel, taking contaminates with it. After the tank fills up from the water, usually with about 1/3 worth of water, you can drain off the water and then continue spraying. the process will need to be completed until the water comes out clear, which means there are no contaminates left.

Mist washing uses more water than bubble washing because it is not circulated continuously through the biodiesel, however, it is a little more convenient since there is less waiting involved since the biodiesel doesn't need so much time to settle out except for in the final draining of the water.

What to do with your wash water

Wash water should not be dumped down the drain, especially if you have a septic tank installed. The methanol, soaps and other contaminates pulled out of the bioidesel can be hazardous to marine life and will kill the bacteria needed in a septic system. Check with local laws and codes about disposal of your wash water. Some larger operations tend to have a holding tank outside which can dry in the sun and once the water has all evaporated, the solids can be scooped out and disposed of into a landfill, according to local laws. if you do this, make sure your tank/wash water holding area is much wider than it is tall. you will need as much surface area contact with the sun as possible for fast evaporation. Water takes a lot of energy to heat, and even more to evaporate. If you live in a rainy area, this is probably not the best way to handle this.

We used to rid of our wash water through evaporation by using coolant from our bus engine while driving and circulating it through a radiator in a metal tank. Since most people are doing this process at home, this isn't really an option, however, it brings out other ideas as described below.

Another option to consider would be to again utilize a solar water heater.The best way to do this is to get a metal drum or some sort of temperature resistant container, drop an old radiator into it with the wash water, and circulate the hot water from your water tank or even fluids directly from the solar heater through the radiator. It will heat up the water throughout the day and evaporate it out much more quickly than just plain sunlight.

other users may find it convienent to boil the water out of a drum by burning a fire under the drum or using heat from a boiler or wood stove with a medium fluid similar to the set-up for the solar water heater. Most methods will work if it involves adding heat to the water for a good amount of time, but i only really want to promote the greener way of doing it. Other methods that expend energy may save time but are essentially wasteful. If you don't have the patience for getting out the water to save money on the wash water disposal, i would recommend dry washing instead.

Dry- Washing biodiesel

Water washing is often complicated and requires a lot of timeand care for each batch of biodiesel. A few dry-washing methods have been developed to help speed up the process and make it a lot easier. Dry-washing also prevents chances of an emulsion when a bad batch has been made and can even produce a higher quality product if the dry-wash is done properly. Best of all, dry-washing does not leave you with messy wash water that has to be disposed of properly and it saves you the cost of water as well. For some locations, dry-washing is more cost effective.

Magnesol D-60

Magnesol is popular for dry-washing biodiesel. The D-60 product has been produced by The Dallas Company and tested specifically for dry-washing Biodiesel, guaranteed to yield a high quality product. Magnesol is basically a Magnesium Silicate compound, similar to common talc powder. The powder is extremely fine and will get everywhere if you drop it on the ground. Take care when using it as it can get into your lungs and irritate them.

Magnesol is simple to use. Simply add the appropriate amount to your biodiesel after draining of the glycerin and then circulate/mix the biodiesel for about 15 to 20 minutes. the magnesol will dissolve into the Biodiesel and then attach itself to the soap particles suspended in the biodiesel.

Once you are finished mixing the Biodiesel with the magnesol, simply run it through a 1 micron filter to remove the magnesol/soaps. It's best to use polyester bag filters for this since they are cheap and have large surface area. It is also best to pass through 2 or 3 filter bags to ensure all of the magnesol is removed. This can be done through by passing it through the same bag 2-3 times or stuffing 2-3 bags inside of each other and doing it all in one pass. Filtering can be done with gravity filtering or also with a pump. if you use a pump you can push the biodiesel through the bag filters with our adapter heads and pass through 2 or 3 bags at a time. You can also use our filter bag housing for constant and fast recirculation. when we filter out our magnesol, we circulate the biodiesel through an adapter head with 3 bag filters attached, back into the mixing tank and then when finished, pump through the filter bag housing as a final filtering device before dispensing into our tanks.

Some users will find that a lot of magnesol is required to fully clean their biodiesel. Part of the reason why is that methanol still exists in the biodiesel and it should be removed before performing the wash. Excess methanol can be removed by distillation (heating to boil and then condensing into another container). This excess methanol can be used for the next biodiesel batch so it is highly recommended to have a methanol recovery system.

In order to determine how much magnesol should be used, a soap titration must be performed. The soap titration requires a 0.01N Hydrochloric acid solution, isopropyl alcohol and a sample of the biodiesel. Since lab grade 0.01N Hydrochloric acid is expensive, most users will mix our 32% Industrial grade hydrochloric acid with distilled water to make it themselves. See the soap titration instructions for more information.

Ion-Exchange Resins

DudaLite, PuroLite® and Amberlite®

Ion-exchange resins can be used for dry-washing biodiesel by use of an ion-exchange tower. The process is performed by slowly pumping biodiesel to the top of the tower and down through the resin. The resin will slowly purify the biodiesel as it passes through it. When the biodiesel comes out the bottom, it will be clean of all contaminates and ready for use after a quick filtration of any small particles which may have come with it.

Ion-exchange towers are often made of metal since the resins expand as they are used. Plastic or PVC towers run the risk of being blown open from the expansion since the biodiesel is pumped under pressure. Some resins will expand up to 130% of their initial volume before they are fully used up. Towers should be built to accomodate for this expansion. Screens are installed on the bottom of the tower to prevent the resin from falling out as the biodiesel drains.

The towers should be built to be taller than they are wide. The aspect ratio should be at least on a 1:3 ratio. That is, the height should be 3 times as much as the width. The height should also be at least 24 inches to ensure enough contact with the resin. The wider the tower is, the more flow rate it will be able to handle. The taller the tower is, the more purification can be performed on the biodiesel passing through it. These heights and widths are based on the part of the tower which will be filled with resin. Don't forget to at least double the height to accomodate for expansion!

Most users will prefer a smaller tower since a high flow requires a rather large tower, and they will leave the pump on overnight. Ideally, a diaphragm pump should be used when pumping biodiesel through the ion-exchange towers. Diaphragm pumps can run non-stop or overnight without damage and are easier to control. Flow control is very important since the biodiesel needs enough time to be fully purified. When using a diaphragm pump, the flow can easily be controlled by using a ball valve on the outlet or some sort of other regulation device. Our diaphragm pumps will build up to 40 psi and then shut off, slowly releasing the biodiesel through the piping and into the tower at the flow rate needed.

(Information here is incomplete) on ion-exchange resins, check back for more on tower sizing and operation)

Soap Titration

(to be added)

7. Methanol Recovery Systems

(To be added)

8. Using biodiesel

The use of biodiesel is simple. make sure you filter it, preferably down to 1 micron and then just add it to your tank and go! If your vehicle is new to biodiesel, your fuel filter will require 1-2 changes about a tank or 2 after first use. This is because it is a very good cleaning agent and will soak up all of the junk in your tank from years of filling it with petro-diesel.

We recommend using 1 micron filters because there can be losses in efficiency during the filtration process and your onboard fuel filters will have to do the work if your own filtering does not. Onboard filters are much more expensive than our filter bags and will reduce your fuel economy if they are clogged. We usually pump right from our storage tank, through a filter bag housing with a 1 micron filter bag and then right to the vehicle's tank using a gas nozzel.

Once you have filled your tank with your own Biodiesel, you will never want to use petro-diesel again. It's cleaner, cheaper and smells really nice. You can also feel good about it by knowing that you are saving the planet.