Biodiesel: Do-it-yourself Production Basics
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Biodiesel: Do-it-yourself Production Basics



Biodiesel: Do-it-yourself Production Basics

Biodiesel: Do-it-yourself Production Basics



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    Biodiesel: Do-it-yourself Production Basics Biodiesel: Do-it-yourself Production Basics Document Transcript

    • Biodiesel: Do-it-yourselfATTRA production basics A Publication of ATTRA—National Sustainable Agriculture Information Service • 1-800-346-9140 • www.attra.ncat.orgUpdated by Rich Dana This publication is an introduction to home biodieselNCAT Energy production. It includes lists of equipment andSpecialist materials needed to make small batches of biodiesel.© 2009 NCAT It describes biodiesel and includes cautionary notes and procedures for making test batches and 5-gallon batches. An extensive resource list is also provided.Contents IntroductionHazards .............................. 1 Biodiesel is an alternative to petroleumStorage of chemicalsand biodiesel ................... 3 diesel. Biodiesel is permanently thinned plant- or animal-based oil, with a viscos-Materials ............................ 4 ity approximating that of standard No. 2Sodium hydroxideversus potassium diesel fuel. The fuel is called biodieselhydroxide .......................... 4 because it is made from mostly biodegrad-Cost...................................... 4 able materials and can be used as fuel inHow to do a titration..... 5 diesel engines. Biodiesel can also be used Materials for making a table-top batch of biodiesel.Equipment ........................ 6 in boilers or furnaces designed to use Photo by Ericka Dana.Choosing a scale of heating oils or in oil-fueled lighting equip-production........................ 6 ment. It can be used neat, meaning provide fuel for diesel machinery on a farmMaking a table-top 100-percent biodiesel, or it can be blended or ranch. Please note that biodiesel used onbatch of biodiesel ......... 7 with petroleum diesel. public roads is subject to federal, state andWashing biodiesel ......... 9 local taxes, just as petroleum diesel is. The purpose of this publication is toMethanol recovery ...... 10 describe how people can make biodiesel to Biodiesel can be made in any quantity,Glycerol disposal .......... 11 from 1 cup to many gallons. The processConclusion ...................... 11 described here is a batch process, whichFurther resources ......... 11 Straight vegetable oil (SVO) is appropriate for an individual farmer or Under the proper conditions, either new rancher. Steady flow processes are more or used vegetable oil such as cooking oil appropriate for biodiesel manufacturing can be used as a fuel for diesel engines plants. Because small mistakes are pref- without processing the oil into biodiesel. erable to large mistakes, people interested Vegetable oil must be filtered to 5 microns in making biodiesel may want to start or smaller and heated to at least 140 degrees with small batches and work up to making Fahrenheit for use in diesel engines. Other larger batches.ATTRA—National Sustainable common terms for unprocessed vegetableAgriculture Information Service( is managed oil running in a diesel engine include pureby the National Center for Appro- plant oil (PPO), which is the same as SVO, Hazardspriate Technology (NCAT) and isfunded under a grant from the and waste vegetable oil (WVO) Although Making biodiesel is relatively simple; someUnited States Department of SVO has some advantages over biodiesel, say it is easier than making beer.Agriculture’s Rural Business- SVO has been shown to shorten engineCooperative Service. Visit theNCAT Web site ( life and cause other fuel-related problems. However, there are caustic, toxic, volatilesarc_current.php) for See the Further resources section for more and f lammable chemicals involved. Themore information on information about using SVO for fuel. potential for personal injury and propertyour sustainable agri-culture projects. damage is very real. Neither the author nor
    • nor anyone else associated with this publi- heating the used oil, be careful to keep cation is responsible for potential mistakes, it from spattering and making the fl oor injuries and damage. Do not rely solely slippery. Be cautious about using burn- on this publication for information about ers or electric heaters, just as if you were making biodiesel; carefully study other cooking. Hot oil will melt plastic buckets, publications and start small. creating a mess. Be careful to cool hot oil to below 120 degrees before pouring it into Wear an appropriate respirator when a plastic bucket. making biodiesel. The only approved respirators for methanol are respirators Do not use anything that comes in with external air supplies. For informa- contact with biodiesel or the chemicals tion on obtaining a respirator, see the used to make biodiesel for food production. Further resources section at the end Making biodiesel requires a well-venti- of this publication Other necessar y lated area to reduce the danger of fi re equipment includes heavy rubber gloves, and explosion and exposure to metha- safety goggles and clothing that will nol. Methanol can vaporize, and when protect your sk i n from chem ica ls, mixed with the proper amount of oxy- especially methanol. Methanol can be gen and an ignition source, can igniteRelated ATTRA with an invisible fl ame. When makingPublications absorbed through the skin and cause biodiesel in larger quantities, make it illness, blindness and debilitation.Biodiesel: outside or in a place where there is noThe Sustainability Heating the oil to remove the water chance of a spark or fl ame coming in con-Dimensions and transferring the heated oil are tact with the methanol. Any wiring inBiodiesel Use, t wo potent ia l ly dangerous steps in indoor areas where methanol is used mustHandling, and Fuel the process of making biodiesel. When be explosion-proof.QualityOilseed Processing forSmall-Scale ProducersRenewable Energy About biodieselOpportunities on Biodiesel is made by chemically reacting vegetable oil or animal fat or a combination of oils andthe Farm fats with alcohol, usually nearly pure methanol, denatured ethanol or ethanol. The mixture is then combined with a catalyst: an alkaline chemical such as potassium hydroxide or sodium hydrox-Biodiesel Production ide, also known as lye. The oil is chemically acidic. The combination of the alcohol and catalyst,for On-Farm Use also known commonly as methoxide, is chemically a base. This chemical reaction breaks the fatThe Sidestreams of molecules in the oils into an ester, which is the biodiesel fuel, and glycerol. This reaction is calledBiodiesel Production transesterification. Because the biodiesel is not as dense as the glycerol, the biodiesel floats on top of the glycerol and may be poured or pumped off, or the glycerol can be drained off the bot-Introduction to the tom. The fuel can then be filtered and used in heating or lighting applications. Although someDiesel Engine people use the fuel in diesel engines without further processing, it is strongly recommendedBasic Chemistry of that impurities such as soap, unreacted alcohol and catalyst be removed first by a washing pro-Biodiesel cess. Unwashed biodiesel is caustic and incompatible with modern fuel-injection systems and use will lead to component failure. Modern diesel engines made after 2004 require high-quality fuel to avoid problems. Anyone who has experience with diesel engines knows that diesel fuel will turn into a waxy gel at low temperatures. This is called the gel point and fuel at the gel point cannot be pumped until it is warmed up. The temperature at which the fuel will no longer pour is called the pour point. Biodiesel has a higher pour point than No. 2 petroleum diesel. This means biodiesel gels at a higher temperature. Some oil feed stocks, such as coconut oil or animal fats, result in biodiesel that will gel at relatively high temperatures, whereas biodiesel made from canola or rapeseed oil will have a lower gel point. Biodiesel is commonly blended with No. 1 petroleum diesel to lower the gel and pour points. Biodiesel should be stored at above-freezing temperature, and tempera- ture controlled heaters can be installed on tanks and fuel lines in diesel vehicles. Some vehicles have heated fuel filters that also help keep biodiesel above the gel point.Page 2 ATTRA Biodiesel: Do-it-yourself production basics
    • Storage of chemicals destroy asphalt and concrete if spills were not cleaned quickly. Most petro-and biodiesel leum fueling equipment can be used forFeedstock s a nd f i n i shed biod iesel biodiesel but the equipment degradesmust be properly stored. Methanol is a more quick ly. For more information,poison. Avoid all contact with methanol, see the ATTRA publication Biodieselincluding skin contact and breathing in Use, Handling, and Fuel Quality.fumes. Contact with methanol can causeirreversible illness, blindness and death.Because methanol absorbs water it should Materialsnot be stored in any open container. As mentioned above, biodiesel produc-Methanol should be stored in appropri- tion requires three inputs: oil or fat,ate, sealed containers and containers a lcohol and a caust ic, st rong-baseshould be clearly marked as containing catalyst. Approximately 80 percent bymethanol. Catalyst materials like sodium volume of the feed stock of biodiesel ishydroxide (NaOH) and potassium hydrox- vegetable oil or animal fats and about 20ide (KOH) are strong bases and extremely percent is methanol. Proper reaction of the Acaustic. These chemicals also absorb raw oil requires 20 percent methanol. For void allwater and will become unusable unless example, a proper ratio is 10 gallons of contact withkept in a tightly sealed container. oil to 2 gallons of methanol. The ratio of catalyst varies depending on materials methanol,Oil feed stocks can go rancid or even be used. One gallon of raw oil yields nearly including skin contactrancid when acquired. Avoid rancid oils.Used oil should be turned into biodiesel 1 gallon of fi nished fuel. and breathing inas soon as possible in order to keep it from New, degummed vegetable oil or waste fumes. Contact withgoing rancid and increasing the amount vegetable oil from restaurants can be methanol can causeof free fatty acids. Rancid, wet or heavily used for the oil component. The better the irreversible illness,used oil produces less biodiesel and may quality of the oil, the easier it is to make blindness and death.not even react enough to make biodiesel. high-quality biodiesel. Oilseed farmers canFinished biodiesel can be safely stored for press and degum oil or get pressed rawsix months. oil. See the ATTRA publication OilseedImproper storage of biodiesel, waste Processing for Small-scale Producers forvegetable oil and glycerol can attract more information.rodents. Be careful to keep a clean work- Methanol, or wood alcohol, was oncespace and dispose of waste quickly. made through pyrolysis of wood, but nowMice and rats can quickly chew through methanol is made primarily from naturalplastic containers, so be vigilant. Keep the gas. It is used as a gas-line antifreezework area secure from small children and and for racing fuel. Methanol is avail-pets, as the biodiesel can have an attrac- able from chemical suppliers. Metha-tive, sweet smell. Biodiesel-soaked rags nol in 55-gallon drums is available fromand paper towels can spontaneously fuel dealers, auto parts stores or speedcombust and care must be taken to avoid shops. HEET gas-line antifreeze is 99-this possibility. percent pure methanol and can be usedFinished biodiesel should be stored in to make small batches of biodiesel. Besteel drums, poly totes or yellow die- sure to purchase HEET that is sold insel cans, and these containers should yellow bottles. Iso-HEET, which is soldbe clearly marked as containing biodie- in red bottles, is isopropyl alcohol andsel. Biodiesel is a good solvent. It will will not work. Do not assume that fuel-dissolve rubber and some plast ics, line antifreeze is pure methanol unless itremove paint, oxidize aluminum and is labeled as such. Be sure to use nearlyother metals and has been reported to pure ATTRA Page 3
    • For the cata lyst, sodium hydroxide because of its superior catalyst properties. (NaOH, caustic soda or lye) or potassium Potassium hydroxide dissolves more easily hydroxide (KOH, caustic potash) can be in methanol and is less sensitive to water. used. Until recently, sodium hydroxide In addition, the glycerol, or glycerin was commonly sold as a drain cleaner by-product of processing with potassium in the form of Red Devil-brand lye and hydroxide, remains liquid and is easier was available from hardware stores and to dispose of. The by-product can also many grocery stores. It has been discon- more safely be added to compost piles, tinued by the manufacturer. If purchasing used in small quantities as a supplement another brand of lye drain cleaner, make to animal feed for ruminants or poultry sure it is pure lye. Potassium hydroxide and applied as potassium fertilizer. Using is less commonly available, but can be sodium hydroxide contaminates the wash purchased through chemica l supply water with salts, rendering it inappropri- houses or farm chemical suppliers. ate for land application. Sodium hydrox- The amounts of methanol, potassium ide glycerol does have advantages of hydroxide and raw oil used to make its own: it makes a superior base for soap biodiesel are adjustable, as long as the or degreaser. following formula is followed: 1000 milliliters of oil to 200 milliliters of meth- anol to 7 grams of potassium hydroxide. Cost If you prefer to use sodium hydroxide, the In addition to the initial cost of the correct amount in the formula would be processing equipment, biodiesel produc- 3.5 grams. For used oil, see the section tion costs include the chemicals used in on How to do a titration below. the reaction, gas or electricity expenses and labor. Feed stocks can range from Sodium hydroxide versus new food-grade cooking oil to animal fat renderings. The cost of the feed stock is potassium hydroxide very specifi c to the producer’s location Sodium hydroxide (NaOH) is the least and operation. Waste oil from restaurants expensive and most commonly used is becoming a valuable commodity, but a l k a l i ne component i n t he sma l l- many local restaurants are still willing to sca le biodiesel product ion process. give producers waste oil for free. Farmers However, in recent years, potassium who grow oilseeds may be able to press hydroxide (KOH) gained popularity oil at the farm for a relatively low cost. Methanol costs fluctuated wildly in recent years, along with gasoline and natural gas Collecting waste vegetable oil (WVO) prices. Expect to pay roughly 25 percent Although some biodiesel producers pay for waste vegetable oil, it more for methanol than the current pump is often available for free from restaurants. Shop around. Smaller price for gasoline. Look in the phone restaurants may let producers pick up waste oil in buckets or book for fuel suppliers or speed shops. drums, if the producer provides exchange buckets. Find out when the fryer oil is to be changed, and pick it up warm if possible. To Catalyst costs start at about $2.50 per get the best oil, talk to the restaurant owner and, more impor- pound. Shop around to get the best price. tantly, to the head cook, and inform them about the project and Remember, hazardous chemical shipping oil requirements. Most restaurant owners will be happy to work costs can be significant for chemicals with producers who are conscientious and don’t make a mess. Do purchased over the Internet. not take oil from grease Dumpsters at the back of a restaurant. The oil may have excess water and be of poor quality. Taking oil As of 2009, farmers can expect to may also constitute theft. Check with state and local governments produce biodiesel from free, waste grease for any necessary permits, as some jurisdictions charge fines for for between $1 and $2 a gallon, before improper disposal of used oils. accounting for labor and paying any applicable state and federal road tax.Page 4 ATTRA Biodiesel: Do-it-yourself production basics
    • Making your first batch of biodiesel There are many techniques for making biodiesel in batches from 1 cup to 90 gallons. Many kits are available for sale online, as well as do-it-yourself plans. Check the Further resources section for links. Regardless of the scale of the operation, the same six basic steps apply. 1) Collect oil There are many sources of oil, including growing oilseed crops and collecting waste oil. Some basic rules apply regardless of the source. Oil must be relatively free of solids and water. If collecting used cooking oil, work with establishments that change their oil regularly. This means at least once a week, depending on amount of use. The quality of the oil is impor- tant, too. Soy or canola oil is preferred because tropical oils and animal fats require more chemicals and produce a finished biodiesel with a higher gel temperature. 2) Test the oil Waste vegetable oil contains free fatty acids (FFA), and the amount of free fatty acids in the oil is very important because it determines the quality and quantity of the fuel produced, as well as the amount of chemicals required and the cost per gallon. Titration is a simple technique used to determine the quantity of free fatty acids in oil. When using waste oil, try to use oil with a titration value of five or below. Titration is also discussed later in this publication. 3) Process the oil The reaction between oil and the methanol-catalyst mixture, known as methoxide, can take place in a container of any size, but the container needs to be resistant to the corrosive nature of the oil and chemicals involved. On a small scale, a glass beaker or jar or a 1-liter plastic bottle are generally safe bench-top vessels. See the Making a table-top batch of biodiesel section of this publication for more information about producing biodiesel in a 1-liter plastic bottle. Some older literature refers to mixing biodiesel in a blender. DO NOT use a blender to mix a small batch of biodiesel. The reactants dissolve rub- ber gaskets, causing leaks. The violent mixing can also cause splashing of caustic chemicals. On a larger scale, a closed steel container is the safest option. See the section about batch processors for more information. 4) Remove glycerol After the reaction, the glycerol by-product will settle to the bottom of the vessel. This glycerol must be removed before the biodiesel can be used. Most larger reactors include a drain at the bottom of the vessel that allows the denser by-product to be removed. In a bench-top situation, the biodiesel can be poured off or removed with a pipette or baster. 5) Wash and dry the biodiesel Even after the reaction has taken place and the by-product has been removed, the biodiesel can contain impurities, includ- ing soaps and residual glycerol, methanol and lye. Passing a small quantity of water through the biodiesel removes the impurities and stops any remaining chemical reaction. 6) Dispose of the glycerol Proper disposal of the by-product is essential. The glycerol contains unconsumed methanol and catalyst, which can find their way into groundwater. See the section titled Methanol recovery for more information on this process.How to do a titration parts stores and is about 100 percentAs stated in the box above, titration is a isopropyl alcohol. Isopropyl alcohol is alsosimple laboratory technique used to deter- available at pharmacies.mine the level of free-fatty acids in used oil, 2) One bottle of phenolphthalein (preferred)and the amount of reactant chemicals that you or phenol redwill need to completely process your feed-stock. Follow these instructions to determine Phenolphthalein is available at hot tub storesthe proper amount of catalyst before making and home centers.each batch of biodiesel from waste oil. 3) One liter of 0.1 percent catalyst in distilled waterMaterials It is important to measure the catalyst1) One bottle of isopropyl alcohol very accurately. The accurate amounts areIn the United States, Iso-HEET Premium 1 gram of catalyst (sodium hydroxide orFuel System Dryer & Antifreeze, in a 12 potassium hydroxide) dissolved in 1 liter offluid ounce red bottle, is available at auto distilled ATTRA Page 5
    • In the absence of a scale capable of 5) Keep track of how many milliliters of measuring small amounts, one way of 0.1-percent solution are needed for the achieving precise measurements is to mea- liquid to turn and stay red. sure out 10 grams of catalyst and dissolve The number of milliliters of 0.1-percent it into 1 liter of distilled water. Now take solution needed is equal to the number 100 milliliters of this water and mix it with of extra grams of pure catalyst needed 900 milliliters distilled water. You now to produce the proper reactions to make have 1 gram of catalyst in 1 liter of dis- biodiesel. For example, if it takes 3 tilled water. A local pharmacist or high milliliters of 0.1-percent solution to turn the school science department can also do the measuring. Leftover solution can be oil and isopropyl alcohol solution to a base, stored in a sealed container for future test add 3 grams of catalyst to the 3.5 grams of batches. Remember sodium hydroxide and sodium hydroxide or 4 grams of potassium potassium hydroxide are very caustic and hydroxide needed for new oil, for a total of even a very small amount can burn skin. 6.5 grams of sodium hydroxide or 7 grams of potassium hydroxide.B Equipment uying 1) A 1-cup jelly jar or other similar glass Choosing a scale of production chemicals After trying a table-top batch, decide on a container in bulk and production system that is scaled to fit avail-mixing batches in Remember to never use biodiesel production able space, available feedstock and fuela safe and efficient containers for food preparation. needs. Batch mixing can be done on a varietyreactor saves time, 2) Two 1-milliliter syringes with gradua- of scales, and there are several system designs tions marked on the side to consider. Batches of 10 gallons or less canmoney and head- be mixed with gentle agitation or stirred withaches in the long run. Note that one syringe is for oil and one is a paint mixer. It is a simple, inexpensive pro- for the lye-water mixture. Always use the cess, but this type of paddle mixing can leave same eyedropper for the same chemical; unreacted material and lead to lower-quality do not mix them up. fuel. Mixing in an open-top container can lead 3) Safety glasses and rubber or nitrile gloves to splashing chemicals and the release of dan- gerous and flammable methanol fumes. Most popular small-scale production systems cur- Procedure rently in use are in the 30- to 50-gallon range 1) Pour 10 milliliters of room-tempera- and utilize circulating pumps to provide con- ture isopropyl alcohol into the 1-cup sistent mixing in a closed mixing container. jelly jar. Although a small-scale mixer or crude 2) Add 2 or 3 drops of phenolphthalein to paddle mixer may be inexpensive to the alcohol. build, remember that economies of 3) Using one of the eyedroppers, add scale apply. It can take the same amount of the 0.1-percent solution drop by drop time to produce 10 and 30 gallons of biodie- until the alcohol just starts to turn red. sel. Buying chemicals in bulk and mixing Stir the alcohol while dropping in the batches in a safe and efficient reactor saves 0.1-percent solution. time, money and headaches in the long run. 4) Using the other eyedropper, add There are many designs for building a exactly 1 milliliter of the oil to be processor and countless turn-key kits titrated. Now, fi ll the eyedropper with available. An in-depth discussion of pro- 10 milliliter of 0.1-percent solution. cessor design and construction is beyond Start dripping this solution into the the scope of this publication, but more mixture until it stays pink for at least information is available in the Further 20 seconds. resources section.Page 6 ATTRA Biodiesel: Do-it-yourself production basics
    • Making a table-top batch of biodiesel Rubber gloves In the past, many biodiesel enthusiasts made demonstra- Safety glasses tion batches using a kitchen blender. We strongly recom- Mixing the methoxide is the most potentially hazardous mend that you DO NOT make biodiesel in a blender. The step in the biodiesel process. Make sure that you mix the high speed of operation can cause splashing of caustic methanol and catalyst in a clean glass jar with a tight fit- chemicals, and the rubber and plastic parts can degrade ting lid. DO NOT mix in a plastic container because the and leak. The easiest and safest method to try a small batch container may dissolve. Do your mixing in a well-ventilated of biodiesel is the one originated by users at www.biodie- area, as the methanol fumes are toxic. Nicknamed the “Dr Pepper Technique,” it utilizes a 2-liter plastic soda bottle as a sealed mixing vessel to safely mix a small batch. Below is the author’s adaptation of this method. Before beginning this or trying any biodiesel processing at home, please refer to all hazards and safety precautions discussed in this publication as well in the articles listed in the Further resources. Measure 4 grams of sodium hydroxide or 5.6 grams of potassium hydroxide using your scale. Add the catalyst to your clean glass mixing jar. Before beginning, make sure that you have all of the equipment and materials you need to complete a batch. Materials 1 liter of new vegetable (cooking) oil Catalyst, either sodium hydroxide or potassium hydroxide Methanol, commonly available as HEET fuel line treatment in the yellow bottle. DO NOT use Iso-HEET in the red bottle; this is isopropyl alcohol. Equipment A clean, dry 2-liter soda bottle Measure 250 milliliters of methanol, using a graduated A measuring cup or graduated beaker beaker or measuring cup to measure. Add the methanol A scale to the glass mixing jar with the catalyst. A glass jar to mix the methanol and catalyst to Stir the methoxide mixture until the catalyst is com- produce methoxide. pletely dissolved. You can also cover the jar with a tight- A funnel fitting lid and mix the methoxide by swirling or shaking, ATTRA Page 7
    • but be very careful that your lid is screwed on tightly and completely free of leaks. It will take a few minutes for the catalyst to dissolve completely, so be patient. The mixture creates heat as the chemical reaction takes place and the jar will feel warm. This is normal. Put the cap on the soda bottle and shake vigorously for about 30 seconds. Let the mixture settle and then shake again for about 10 seconds every 10 minutes; repeat this three times. Allow the bottle to stand for an hour. The mixture will begin to clear almost immediately and a layer of darker liquid will begin to form on the bottom of the bottle. Measure 1 liter of oil, and use your funnel to pour it into the 2-liter soda bottle. You will get a better reaction if the oil is warm. About 140 degrees Fahrenheit is ideal. You can heat the oil in a pan on the stove or just leave it in the sun for an hour. If you choose to pre-heat the oil, be very careful not to get the oil hotter than 140 degrees. The darker layer on the bottom of the bottle is glycerol, the by-product of the transesterification process. You can now drain off the glycerol by taking off the bot- tle cap, covering the open mouth of the bottle with your thumb and inverting the bottle. Wear gloves. Allow the glycerol to collect in the neck of the bottle and then use your thumb as a valve to drain the darker liquid into Add the methoxide solution to your oil. Use a funnel and another container. Discard the glycerol by composting be careful not to spill. If you spill, clean up the material or use it as a degreaser. What remains in the bottle is immediately with paper towels and dispose of the useable biodiesel. contaminated paper towels safely. Photos by Ericka Dana.Page 8 ATTRA Biodiesel: Do-it-yourself production basics
    • The Appleseed processor For the last several years, many do-it-yourselfers chose to avoid the more-expensive kits on the market and opted to build their own processor using an electric water heater as the reactor. This water heater-based platform was developed by biodie- sel home brewer Maria Alovert. Alovert, or Girl Mark as she is commonly known on Internet biodiesel forums, set out across the country in 2004 to share her open-source design through a series of workshops. Because Alovert spread her design like the nurseryman Johnny Appleseed spread apple seeds across Ohio, Indiana and Illinois, her design became known as the Appleseed. Links to complete Appleseed plans are available in the Further resources section. The Appleseed design uses the water heater’s existing tank, plumbing, insulation, thermostat and heating element as the starting point for a remarkably simple, reliable and inexpensive design. Although a used water heater can often be found for free, they can be problematic if they leak or contain large amounts of rust, limescale or other impurities. A new electric water heater can be found on sale at home centers for as little as $200. The plumbing parts, pumps and electrical supplies necessary for the completion of the unit can be purchased for about $150. In this design, the oil is pumped into the water heater tank, brought up to a constant temperature of 130 degrees Fahrenheit using the built-in heating element and thermostat. While heating, the methanol and catalyst are premixed in a high-density polyethylene (HDPE) carboy or jug. The oil is circulated from the bottom of the tank to the top, and the methoxide is intro- duced slowly from the carboy through a permanent hose. This greatly reduces the risk of spilled chemicals and injury. After about an hour of mixing, the circulating pump is turned off and the glycerol settles to the bottom, where it can be drained off. The biodiesel can then be pumped out to another tank for washing and drying. One of the beauties of this design is that, by using a series of bypass valves, the same one-half horsepower centrifugal pump can be used for filling, mixing and emptying the reactor. This is also a very safe design appropriate for small-scale production. Many variations on the design are available for free online, as well as designs for countless add-ons like standpipe wash tanks, drying systems and methanol recovery systems. For the serious do-it-yourselfer who wants to produce high-quality biodiesel for the smallest investment, the Appleseed is a good design to explore.Washing biodiesel some alcohol, catalyst and soap remainUnwashed biodiesel w i l l not meet suspended throughout the biodiesel afterASTM, formerly known as the American the transesterification is complete. WaterSociety of Testing and Materials, stan- in biodiesel can lead to biological growthdards. For more information about ASTM as the fuel degrades. Unreacted methanolstandards and testing and specifications in the biodiesel fuel can result in fi re orfor biodiesel and other diesel fuels, see the explosion and can corrode engine compo-Further resources section. Remember, nents. The catalyst can also attack otherequipment and engine manufacturers only engine components. Because the methanolwarranty their equipment and engines for and catalyst are chemical bases, unwashedtheir material and manufacturer defects. biodiesel is caustic and may damageFuel manufacturers assume responsibility diesel engine components. Soap is notfor any damage caused by the fuel. Wash- a fuel and will reduce fuel lubricity anding biodiesel is easy to do, and requires cause injector coking and other deposits.only water and time. In the small-batch scale described above, it is not feasible to reclaim the methanol.Why wash biodiesel? When making significant quantities of biodiesel, reclaim the unreacted methanolThe biodiesel produced with the process because the reclaimed methanol representsdescribed above will work in some heating a significant cost savings and methanol is aand lighting equipment and may be used to pollutant in its own right.fuel diesel engines. Most impurities settleout into the glycerol layer, including unfi l-tered particulates, methanol and glycerin. Washing your test batchSome sources encourage using unwashed You can easily wash your 1-liter test batchbiodiesel because washing biodiesel is by slowly and gently adding water to youra time-consuming process. However, bottle until it is full. Allow the water ATTRA Page 9
    • fall to the bottom and be removed through Washing techniques the drain valve. There are several common techniques for washing biodiesel, including agitation washing, mist washing and bubble washing. The process of For bubble washing, use an aquarium air washing biodiesel involves mixing it with water. Water is heavier than pump, hose and air stone. For a larger biodiesel and absorbs the excess alcohol, catalyst and soap suspended washing tank, a perforated pipe connected in the fuel. After washing and settling, the water and the impurities in to an air compressor can be used. Gently the water can be drained from the bottom of the container. Several wash add about one-third as much water as you cycles are generally needed. The first water drained off the bottom of have biodiesel to wash. Start the air pump the biodiesel will be milky, and the final wash water drained off will be clear. Excess catalyst in the biodiesel will form soap when mixed with or compressor and allow the bubbles to water, and it takes awhile for the soap to settle out. Depending on the gently wash the biodiesel for several method used, it takes roughly 1 gallon of water per 1 gallon of biodiesel hours. Drain the milky water, and repeat for a wash cycle. The mixing should be thorough and the water should this process, letting the air pump run be dispersed throughout the biodiesel. Agitation washing means stirring longer during each washing cycle, until water into the biodiesel, letting it settle and draining it off. Mist wash- the water remains clear. If the bubbles ing is spraying a fine mist of water over the surface of the biodiesel. Tiny droplets of water fall through the biodiesel and pick up impurities on cause foam to form, use less air. the way down. Bubble washing is done by putting a bubbler in a layer of water beneath the biodiesel. The rising bubbles are coated with water, Drying washed biodiesel which picks up impurities as the water travels up and then back down After the biodiesel is washed, it should through the biodiesel. be dried until it is crystal clear. This can be done by letting the biodiesel sit uncov- settle to the bottom and then use the same ered in a sunny location for a few days, technique used to remove the glycerol. or it may be heated to about 120 degrees Covering the mouth of the bottle with your Fahrenheit for a few hours. Another thumb, invert the bottle, allow the water popular technique is recirculating the to settle and then drain it off using your biodiesel from the bottom of the drying thumb as a release valve. Wear gloves. tank through a shower head or sprayer Repeat the process. suspended above the top of the open tank. This increased contact with air will After washing, the biodiesel will be dry biodiesel in about an hour, depend- cloudy with an appearance similar to ing on humidity. Reacted, washed and orange juice. This is because of residual dried biodiesel may be used in any diesel water trapped in the fuel. Do not use the engine. It should have a pH of close to 7, fuel until you have allowed it to sit with or chemically neutral, and it should have the top off until it is clear. Then you know no methanol left in it. Although profes- the fuel is dry. sional testing of fuel may be prohibitively expensive, simple home fuel test kits can Washing a larger batch be purchased for a reasonable price. One Bui lding a basic washing system is such kit, the The Biodiesel pHLip Test, simple. One option is to use a mist- can be found at ing nozzle similar to those used in a grocery store produce department. Using Methanol recovery an open-head 55-gallon drum or other Because much of the methanol used container with a drain valve connected at the in transesterification remains in the bottom, suspend the mist head over the by-product after reaction, it can be advan- barrel and plumb to a water supply with tageous to recover the unused alcohol hard pipe or a garden hose. Fill the for several reasons. First, reusing the container about half full of biodiesel, and recovered methanol can save a consider- then turn on the water and allow the mist able amount of money when producing head to gently spray the surface of the significant volumes of biodiesel. Second, biodiesel. In a short time, the water will once the alcohol is removed the glycerolPage 10 ATTRA Biodiesel: Do-it-yourself production basics
    • by-product becomes glycerin, a much by-product of biodiesel product ion.more environmentally friendly product While the methanol in the glycerol maywith countless uses. biodegrade up to 97 percent within 72 hours, methanol-laden glycerol should beMethanol recover y can be achieved handled as a hazardous material. Therethrough the distillation process by heat- is debate, though, as to the actual haz-ing the glycerol to a temperature above ard posed by glycerol. Some people usethe boi ling point of methanol, 148 small quantities as a dust suppressant,degrees Fahrenheit at sea level. This degreaser or weed killer. Glycerol cantemperature is lower if the process is be burned in a waste oil burner or added Operformed at a lower pressure. Attaching to a biodigester or a proper composta vacuum pump to the distilling tank low- ne of pile, where it can safely be converted toers the danger of explosion. The vaporized fertilizer. Glycerol has about the same the majormethanol must then be passed through feed value as corn and there are numer- issuesa condenser, cooled and recaptured ous university studies documenting its use to deal with inas a liquid. Biodiesel researchers and as a feed supplement. Check local regula- biodiesel productionenthusiasts are currently exploring several tions before disposing of glycerol. NEVER is the disposal ofsystems and links to more information dump glycerol in a ditch or waterwaycan be found in the Further resources glycerol and DO NOT pour into drains or toilets,sect ion of this publicat ion. Severa l especially if you have a septic system.methanol recovery systems rely againon a water heater to provide a relatively Conclusionsafe, sealed tank to heat the glycerol and This publication is meant as a startingautomotive condensers or homemade cool- point for making biodiesel. It is not aing towers. Because biodiesel made with complete reference guide and we encour-sodium hydroxide will produce a glycerol age you to explore all of the additionalthat is more solid when cool, it is best to information supplied in the Furtheruse potassium hydroxide if recovering the resources section. One of the best waysmethanol, or pump the sodium hydroxide to learn about making biodiesel is bymethanol directly in to the distilling unit joining a local biodiesel club or group.while it is still hot. Classes are offered in many areas through local clubs, community colleges and farmGlycerol disposal groups. Make sure that you have as muchOne of the major issues to deal with information as possible before mixingin biodiesel production is the disposal your fi rst batch, and always remember –of glycerol, the methanol-laden glycerin SAFETY FIRST.Further resourcesUnless noted, none of the biodiesel resources cited Internet discussion groupsbelow are affiliated with NCAT. Joining these groups can be a great way to learn fromBooks those who are producing biodiesel. This is only a sampling of forums on topics like homebrew biodiesel,Biodiesel Homebrew Guide: Everything you need to straight vegetable oil and home heating.know to make quality alternative diesel fuel out of wasterestaurant fryer oil. Maria “Mark” Alovert Biodiesel & SVO Discussion ForumsAvailable at http://biodiesel.infopop.ccBiodiesel Power: The Passion, the people, and the Yahoo Biodiesel Grouppolitics of the Next Renewable Fuel. Lyle Estill at Yahoo Biodiesel Basics Groupbiodiesel-power.html ATTRA Page 11
    • Frybrid Diesel/Vegetable Oil Glycerin Glycerin, from Journey to Forever cooperatives Straight vegetable oil as diesel fuel, fromPiedmont Biofuels Coop Journey to Biodiesel Collective Biodeisel & SVO Discussion resources f/898605551Journey to Forever Frybrid Diesel/Straight Vegetable Journey to Forever is a small, non-government orga- Reclaiming methanol nization based in Japan and involved in Third World BioLyle’s Biodiesel Workshop rural development work. The Web site also offers a lot of information about other appropriate technologies. Biodiesel Safety and Best Management Practices for is a collaborative, Small-Scale Noncommercial Use and Production, from web-based tutorial run by and for people who make Penn State College of Agricultural Sciences their own biodiesel. Collaborative Biodiesel Tutorial: Biodiesel SafetyNational Biodiesel Board Occupational Safety and Health Administration www.osha.govGovernment agencies with biofuelsinformation Respirator selectionOak Ridge National Laboratories National Institute for Occupational Safety and Pocket Guide to Chemical HazardsBiodiesel publications from the National Energy Laboratory Making soap using biodiesel Soap, from Journey to Foreverbiodiesel.html This site offers PDF and HTML files about biodiesel production, handling and use; biodiesel quality, Biodiesel as a home heating fuel stability and compatibility; biodiesel emissions; and Bio Heat biodiesel fleet evaluations. Heaters, burners and stoves, from Journey to ForeverStandards and testing, chemical of biodieselNational standards for biodiesel, fromJourney to Forever Biodiesel: Do-it-yourself production Updated by Rich Dana NCAT Energy SpecialistASTM Standards © 2009 Holly Michels, EditorCetane Number Testing of Biodiesel Amy Smith, This publication is available on the Web at:gen/19960901_gen-187.pdf or scale IP 263 Slot 205 Version 062609Page 12 ATTRA