Make Your Own Biofuels

Biodiesel is able to be made by the average lifestyle block owner – its in your power to make a difference! Become a Biodiesel Homebrewer and make this clean alternative fuel in your backyard.

Become a Biodiesel Homebrewer

Biodiesel can be made from new or used vegetable oils, such as soybean oil, canola oil, sunflower oil, hemp oil, coconut oil, peanut oil, palm oil, corn oil, mustard oil, flaxseed oil, rapeseed oil, cottonseed oil, and waste cooking oil. It can also be made from beef and sheep tallow, pork lard, as well as other types of animal fat. It is made by chemical reaction with an alcohol like methanol or ethanol to produce chemical compounds known as fatty acid alkyl esters (fatty acid methyl esters when methanol is used). The term Biodiesel is commonly used to refer to these esters when they are intended for use as fuel. There is little difference between vegetable and tallow based esters in terms of engine emissions and engine operation.

Biodiesel is actually as old as the diesel engine itself. Rudolf Diesel, the 19th-century originator of diesel technology, used refined peanut oil to run his invention.Rudolph Diesel designed the Diesel engine to be run on a variety of fuels was quoted as saying the diesel engine can be fed with vegetable oils and will help considerably in the development of the agriculture of the countries which use it. Diesels workhorse engine took off, but the rise of cheap crude oil killed his vision of farmers growing their own fuel. Now, after a century of burning fossil fuels, the diesel engine is finding its way back to its agricultural roots thanks to biodiesel costing less than one dollar per litre to produce.

• * Biodiesel fuel burns up to 75% cleaner than conventional diesel fuel made from fossil fuel
• * Biodiesel substantially reduces unburned hydrocarbons, carbon monoxide and particulate matter in exhaust fumes
• * Sulphur dioxide emissions are eliminated (biodiesel contains no sulphur)
• * Biodiesel is plant-based and adds no Carbon Dioxide to the atmosphere
• * The ozone-forming potential of biodiesel emissions is nearly 50% less than conventional diesel fuel

Sources of Oil for Biodiesel Production

If you have access to inexpensive oil or tallow, it can be quite cost-effective for you to manufacture your own biodiesel.

Tallow

Tallow is made from animal fat of cattle, sheep, pigs or goats, which needs to be rendered (purified) to produce the tallow.

Recipe:

• One kg of animal fat
• Ten litres of water
• Three tablespoons of salt
• Three tablespoons of baking soda

To render the tallow, first take the beef fat and cut off anything that does not look like fat. Chop the fat into small pieces or mash it. Put the fat into a large pot and cover it with water. Add three tablespoons of salt. Boil it for 30 minutes, stirring frequently. Remove it from the heat and let it cool. Strain it through an old pair of pantyhose, then cover it. Refrigerate it until the top layer hardens, usually overnight. This solid top layer is the tallow. Take it, discard the rest, and repeat the rendering process. The second time you render the tallow, take the solid layer, put it into the pot, add enough water to cover it, and add three tablespoons of baking soda, not salt this time. Boil it for 30 minutes, stirring frequently. Remove it from the heat, allow to cool, then strain and place back into the fridge. When the top layer solidifies, discard everything else. Now you’re ready to use this rendered tallow to make biodiesel. Store the tallow in the fridge or freezer until you’re ready to use it.

The biggest source of tallow in New Zealand is from cattle and sheep. The animal slaughtering process is a major industry in New Zealand. The slaughtering process produces meat (36 %), rendering products (22 %), hides & skins (8 %), offal (3 %) and the remainder (31 %). Rendering produces tallow at a ratio of 22 % of the total end product, as well as meat and bone meal. The lower grades of tallow are used as the raw material for this process. Tallow is already the base raw material for a 45,000 tonnes per annum multi-feedstock biodiesel plant at Motherwell in Scotland. This plant uses tallow from a rendering plant and used cooking oil as the raw materials for a transesterification process.

Olive Oil

Producing Olive Oil

The oil comes from the mesocarp, or flesh cells, of the fruit of the olive tree and must be extracted from the solid material. The first step is remove the leaves and to wash the harvested olives. You can then crush the olives with either a stone mill or a metal crusher. This will produce a paste from which the oil droplets can be extracted. The traditional stone crusher consists of a stone base and upright millstones enclosed in a metal basin. There are usually scrapers to clean the millstones and paddles plus blades to circulate and expel the paste. This process ensures that the oil finally produced is not contaminated with metal. Where a food grade olive oil is wanted, the stone- crushed olive oil is usually then pressed or centrifuged. The stone crushers are slow and production is limited as it is not a continuous process.

Komet Oil Expellers

Komet Vegetable Oil Expellers are manufactured by IBG Monforts in Germany, whose range of products covers small hand-operated as well as industrial machines. Komet oil expellers feature a special cold pressing system with a single conveying screw to squeeze the oils from various oil-bearing seeds. The machines operate on a gentle mechanical press principle that does not involve mixing and tearing of the seeds. Virtually all oil-bearing seeds, nuts, and kernels can be pressed with the standard equipment without adjusting the screws or oil outlet holes.

The vegetable oil produced needs no refining, bleaching, or deodorizing, as long as the natural taste, smell, and colour are acceptable. Generally, any sediment in the oil will settle to the bottom of the collecting vessel after approximately 24 hours and form a hard cake. You can then pour the oil through a paper or textile filter to remove any remaining impurities.

Metal crushers work by rotating at high speed, throwing the olives against a metal grating. The oil is usually extracted from the paste by a continuous centrifuge. The advantages include speed, continuous operation, low cost and high output. The primary disadvantages include the likelihood for metal contamination.

This method will produce olive oil, must and pomace. The oil must consists of edible olive oil and vegetable water. The waste consists of solid and liquid waste. The solid waste can be used by a lifestyle block holder for fuel, fertilizer, mulch, herbicide and as food for livestock. The most exciting use is for fuel due to the extremely high cost of energy these days. In Europe, a common use of pressing waste is as fuel to heat households and pottery kilns. If completely dried, the solid waste can be pressed into very intense burning logs.

For use as fertiliser or mulch, the olive waste should be mixed with soil and bark but should not be concentrated over tree roots because they may burn. The olive waste can be distributed your orchard or garden as it serves as a natural herbicide, discouraging grass and weed growth. This waste material is also a component of feed for animals such as cattle and poultry but goats and sheep will eat it as is, separating the edible portion from the woody parts.

First Press from The Olive Oil Source a complete make-your-own oil press.

Rapeseed Oil

Rapeseed, also known as Rape or Oilseed Rape, is a bright yellow flowering member of the family Brassicaceae. It is very widely cultivated throughout the world for the production of animal feed, vegetable oil for human consumption, and biodiesel. It is the third leading source of vegetable oil in the world in 2000, after soybean and oil palm. The rapeseed is the valuable, harvested component of the crop. The crop is also grown as a winter-cover crop. It provides good coverage of the soil in winter, and limits nitrogen run-off. The plant is ploughed back in the soil or used as bedding.

Processing of rapeseed for oil production provides rapeseed animal meal as a by-product. The feed is mostly employed for feeding cattle, but can also feed pigs and chickens. The meal has a very low content of the glucosinolates responsible for metabolism disruption in cattle and pigs.

Vegetable Oil

The other option for the production of biodiesel is used or waste vegetable oil. The first step is the collection of the waste cooking oil. This collected raw material is processed by transesterification to yield biodiesel. Recently there was an item on TV about a group on Waiheke Island that were making biodiesel from waste cooking oil. There are many people already collecting used cooking oil from restaurants and takeaway outfits. Most of the time, the owners of such establishments are happy to have someone take away the oil for free as it saves them the tricky job of disposing of it. But if the process becomes more popular, then it is likely they will start charging for the waste oil as happens in USA now. Used cooking oil can go rancid (smell bad) or even be rancid when you get them. Avoid using rancid oils for biodiesel production.

If you can make your own oil or have access to inexpensive oil or grease, such as a by-product of some process, it may be quite cost-effective for you to manufacture your own biodiesel from these byproducts. The quantities of raw materials (oil, methanol, and sodium hydroxide) vary to some degree, depending on the quality of oil that you use. The amount of methanol and sodium hydroxide must be sufficient to cause a reaction with the vegetable oil, but you should not use excessive amounts of these catalysts. The cost of the methanol and sodium hydroxide is significant so you dont want to waste them. As you develop your own biodiesel-making expertise, you will be able to adjust the amounts used to optimize your process and minimize how your usage of the catalysts.

Vegetable oils and animal fats are triglycerides, containing glycerine. The biodiesel process turns the oils into esters, separating out the glycerol. The glycerol sinks to the bottom and the biodiesel floats on top and can be siphoned off. The process is called transesterification, which substitutes alcohol for the glycerol in a chemical reaction, using caustic soda as a catalyst.

How to make a small batch of biodiesel

Vegetable oils and animal fats are triglycerides, containing glycerine. The biodiesel process turns the oils into esters, separating out the glycerol. The glycerol sinks to the bottom and the biodiesel floats on top and can be siphoned off. The process is called transesterification, which substitutes alcohol for the glycerol in a chemical reaction, using caustic soda as a catalyst.

Methanol (methyl alcohol) is used to make methyl esters. The catalyst can be either sodium hydroxide (caustic soda, NaOH) or potassium hydroxide (KOH), which is easier to use and it produces potash fertilizer as a by-product. Sodium hydroxide is often easier to obtain and it is cheaper. If you use potassium hydroxide, the process is the same, but you need to use 1.4 times as much. KOH and other chemicals, such as isopropyl alcohol (isopropanol) for titration, are available from chemicals suppliers.

CAUTION: Sodium hydroxide and potassium hydroxide are dangerous. Don’t get it on your skin or in your eyes.

You will need the following items to make your first batch:

1. One litre of vegetable oil such as sunflower, canola or soyabean.
2. A variable speed blender with a slow speed option. It needs to have a glass container as the methanol used in this process will attack a plastic container. Of course you wont be able to use this blender any more with food products.
3. A scale that will accurately measure 3.5 grams
4. A bottle Sodium Hydroxide, usually available as a drain cleaner from your local hardware store. Make sure the label says contains sodium hydroxide. Some drain cleaners are chlorine (Calcium Hypochlorite) based and will not work.
5. At least 200 ml of methanol (Methyl Alcohol or Wood Alcohol). Methanol is available as a car petrol lines antifreeze in service stations, auto parts stores and hardware stores. Make sure the label says contains methanol as many antifreeze products are based on or isopropanol (isopropyl alcohol) and that will not work. Methanol is both poisonous and flammable so take the necessary precautions.
6. A glass container, like a beaker, that is graduated for 200 ml.
7. A glass or plastic container that is graduated for 1 litre.
8. A wide-mouth glass or plastic container that will hold at least 1.5 litres.
9. A standard spoon (plastic or stainless steel is best).
10. Safety Glasses and Rubber Gloves as Sodium Hydroxide and Methanol are extremely poisonous and must not come into contact with skin or eyes. Methanol is particularly dangerous as it can attack your eyes even if it comes into contact with your hands. Use extreme care when blending the methanol and caustic soda, as there may be splashes of chemicals from the blender. Put on your glasses and safety gloves before opening the chemicals. Do your work near a sink or a hose, or have a bucket of water handy to wash any part of your body immediately if it comes in contact with these chemicals.

Process

1. Get the materials organised in a well lit, well-ventilated area. This process is best done at or above 21 Degrees C. Temperatures lower than 15 C may result in an incomplete reaction. Prepare for the possibility of spills by spreading paper or plastic on your work surface. Don your safety gear.
2. Measure 200 ml of methanol and pour the methanol into the glass container of the blender.
3. Place a piece of flat white plastic onto the scale and tare back the scale to zero. Weigh out 3.5 gm of Sodium Hydroxide.
4. Turn the blender on slow speed and slowly add the Sodium Hydroxide to the methanol. After two minutes stirring, the Sodium Hydroxide should have completely dissolved into the methanol. You now have a mixture called sodium methoxide which must be used right away to make biodiesel. It is not possible to make a large batch of methoxide and store it for use later as it loses potency over time.
5. Add one litre of vegetable oil to the blender. Blend on low speed for 20 to 30 minutes. The ideal speed for this process is one that only just creates a vortex in the oil without splashing the mixture around or frothing it up.
6. After about 30 minutes to 1 hour, you will notice a layer of darker-coloured glycerine settling to the bottom of the container. The lighter layer on top is biodiesel. Wait a few hours the glycerine to settle completely. At that point, you can carefully pour off the lighter biodiesel from the top or use a pump to remove the biodiesel from the jar. You can then discard the glycerine or save it to use in soap making.
7. Pour the finished biodiesel into your diesel tank and hit the road! You have just saved yourself some money and are on the way to saving a fortune.

Recipe Variations

You can also use potassium hydroxide and ethanol as the catalyst as these products may be cheaper.

Ingredients

One litre of vegetable oil

10 gm (1% by weight of the oil) of potassium hydroxide (catalyst)

200 gm of ethanol (200 proof) this is the minimum amount.

Process:

Dissolve the catalyst in the ethanol which will require stirring and slight heating. Add ethanol/catalyst mixture to the oil and stir the mixture vigorously. After 120 minutes of reaction time at room temperature the mixture should be allowed to sit overnight while separation occurs. A successful reaction produces two liquid phases: biodiesel and glycerine. The heavier glycerine will collect at the bottom after several hours of settling. Phase separation can be observed with 10 minutes and can be complete within 2 hours of settling but may take as long as 20 hours. Pour off the biodiesel from the top of the tank.

If you were not successful, make sure that you follow the recipe exactly, and try again. Unsuccessful batches can happen for a variety of reasons. If you are using new oil, a batch can fail because you didnt use pure enough methanol. Or you may have used old sodium hydroxide or you did not mix the solutions long enough. Maybe the temperature was too low. If you do not have two distinct layers in the blender, you probably did not use enough sodium hydroxide. If you have a solid white material in the blender, this is soap.

REMEMBER YOU ARE RESPONSIBLE FOR YOUR ACTIONS AND YOUR SAFETY AND THE SAFETY OF EVERYONE AROUND YOU.

These are dangerous chemicals and care is necessary, especially if there are children at home.

A Larger Biodiesel Process

If you want to make a larger quantity of biodiesel, there are several good recipes available for making a high-quality fuel. As we pointed out earlier, some of the chemicals used are dangerous and safety precautions are essential. Wear protective gloves, apron, and eye protection and do not inhale any vapours. Methanol can cause blindness and death, and you don’t even have to drink it as it can be absorbed through the skin. Sodium hydroxide can cause severe burns, even death. Together these two chemicals form sodium methoxide. This is an extremely caustic chemical – treat it as such. Always have running water handy when working with these chemicals. The workspace must be thoroughly ventilated and no children or pets allowed. Methanol should be stored in appropriate sealed containers, and these should be plainly marked as containing methanol. Sodium hydroxide also absorbs water and will become unusable unless it is kept in a tightly-sealed container.

Process Equipment

Biodiesel can be made in anything from a small blender to an elaborate processor complete with separate tanks for processing, washing, methoxide mixing, settling, and filtering. Most people start by making small batches with minimal equipment and then gradually move up to making large batches using large processors built specifically for making biodiesel. Obtaining equipment is not as easy in New Zealand as it is in Europe or USA where pre-made kits ready to assemble are available for purchase.

In the USA, professionally-built processors can cost as little as $750 but also go up to several thousands of dollars for the more sophisticated plant. Make-your-own kits can be purchased for as little as $300 we aim to have these available to the New Zealand market shortly.

Kiwis are an enterprising lot and will be able to make complete processing plants from junk lying around the farm. Building a processor can be completed in an afternoon in a garage and the processor can be ready to process biodiesel within a few hours of starting the project. Parts are relatively cheap to obtain and there is plenty of information available through online forums and discussion groups. You can source the necessary equipment, such as pumps for transferring oil, methanol, and glycerine as well as various containers for holding oil and completed biodiesel without too many problems. The list below gives the basic gear needed for a small scale biodiesel plant:

Equipment required:

• One 200 litre drum.
• * One 3/4 HP electric motor.
• * Two pulleys which produce 250 rpm and a max of 750 rpm at the mixer blade.
• * A belt for the above.
• * One 30 cm rolled steel rod.
• * Two steel shelf brackets (for the blade).
• * One 38mm brass ball valve.
• * A hinge and a spring to act as a belt tensioned.
• * One 2000-watt electric water heater element.
• * A water heater thermostat.
• * One piece of 38mm diameter piece of steel pipe 10 cm long with male threads on one end.
• * Assorted bits: angle iron, wood, screws, etc.

Assembly:

1. Cut a large opening (about half the top) in the top of the steel drum.
2. Drill 38mm hole in the bottom of the drum.
3. Weld the 38mm diameter pipe in the hole at the bottom of the drum.
4. Attach the 38mm brass ball valve to the pipe. This is the drain valve.
5. Drill a hole in the side of the drum at the bottom, same size as the heater element.
6. Fit the heater element making sure it is not touching the side of the drum.
7. Wire up the heater element.

Chemical mixer:

1. Attach one pulley to the rolled steel rod.
2. Attach the other pulley to the spindle of the electric motor.
3. Weld the propeller to the other end of the rolled steel rod (shelf brackets).
4. Attach the rod, pulley and propeller assembly to one side of the hinge.
5. Weld a piece of angle iron across the top of the drum.
6. Weld the unattached side of the hinge to the angle iron so the propeller and rod assembly sits in the middle of the drum. The hinge should swing the propeller and rod back and forth.
7. Mount the electric motor on the side of the drum.
8. Fit the belt to the pulleys and tighten by wedging a block of wood into the hinge.

You also need to make a simple wooden measuring stick with 10 litre increments.

Other bits:

An hydrometer is a good piece of kit to have to measure the specific gravity of the biodiesel. The specific gravity of biodiesel should be between 0.860 and 0.900, usually 0.880. The specific gravity of vegetable oil is 0.920 therefore the specific gravity of biodiesel should be lower than the vegetable oil used to make the bio-diesel.

Process Times

Biodiesel typically takes 2-5 days from start to finish to make a batch. Most people making biodiesel make anywhere between 100 litres to 500 litres at a time using a batch process.

Breakdown of typical process time intervals:

• * Collecting the oil: 1-2 hours
• * Filtering the oil: 1-2 hours, depending on the amount of oil
• * Titration of the oil: 10-15 minutes
• * Transferring oil to the processor: 10-20 minutes
• * Heating the oil: 1-4 hours (depends on amount of oil, and efficiency of heating)
• * Making the methoxide: 5-20 minutes
• * Mixing the methoxide into the oil: 20-30 minutes
• * Mixing the oil & the methoxide: 2-3 hours
• * Settling the oil: 8-10 hours
• * Draining the glycerine: 5-10 minutes
• * Transferring the Biodiesel to the washing tank: 10-20 minutes
• * First mist wash: 2-3 hours
• * Second mist wash: 2-3 hours
• * First bubble wash: 6-8 hours
• * Second bubble wash: 6-8 hours
• * Transferring Biodiesel to drying containers: 10-20 minutes
• * Drying Biodiesel: 2 hours to 2 days, depending on drying conditions
• * Transferring to storage containers: 10-20 minutes

The recipe consists of 10 litres of new vegetable oil and 2 litres of methanol plus 35 grams of caustic soda (Sodium Hydroxide). Don’t breathe the fumes and keep the whole process away from food and children. As caustic soda reacts with aluminium, tin and zinc, use glass, enamel, stainless steel or HDPE (High-Density Polyethylene) containers for methoxide. Don’t use open containers for processing and mix the methanol in closed containers.

1. Add the caustic soda to the methanol in a glass vessel, stirring for at least two minutes. This produces sodium methoxide. Dont try mixing up a batch of methoxide and storing it. React the methoxide with the oil as soon as it has been made.
2. Warm ten litres of new oil in a closed stainless steel vessel on a hotplate to about 50C to thin it so it mixes better. Don’t let it get too hot or the methanol will evaporate. (Methanol boils at 64.7C).
3. Stir well, and carefully add the sodium methoxide to the oil. The reaction should start immediately, with the mixture rapidly separating into a clear, golden liquid on top with the light brown glycerine settling out at the bottom. Keep stirring for an hour, keeping the temperature constant and then let it settle overnight.
4. Next day, siphon off the biodiesel, leaving the glycerine in the bottom of the bucket.

Biodiesel must be washed before use to remove soaps, excess methanol, residual caustic soda, free glycerine and other contaminants. The easiest way of doing this is just to add water. The water will emulsify the glycerine and turn it into glycerine soap which will sink to the bottom. So spray ten litres of water onto your biodiesel and let it settle overnight. Drain off the water from the bottom of the container using a valve and repeat the process until the water draining off is clear. Heat the washed biodiesel up to 50C to evaporate any residual water, and then filter it through a 5-10 micron fuel filter.

Biodiesel from Waste/Used Cooking Oil

The difference in the process when using waste cooking oil instead of new oil is that you will need more caustic soda as a catalyst to start the process as the quality of your oil is poorer. When using waste oil, you will need to perform a titration to determine how much additional catalyst is needed. You could try making multiple small batches of biodiesel, varying the quantity of sodium hydroxide until the reaction works but titration is simple enough and it will save you time and materials. There are several different methods of titration methods but the simplest is one using a chemical indicator called phenol red. This titration method should give you an accurate indication of the additional amount of sodium hydroxide needed to neutralise the free fatty acids in the waste vegetable oil. Other titration methods are similar except for the method used to determine when a prepared solution changes from an acid to a base.

The Titration Procedure

1. Pour 10 ml of room-temperature iso-propyl alcohol into the one-cup jar.
2. Add 2 or 3 drops of phenol red to the alcohol.
3. Using one of the eyedroppers, slowly, drop by drop, add the 0.1% lye-water solution until the alcohol just starts to turn red. Stir the alcohol while dropping in the lye-water.
4. Using the other eyedropper, add exactly 1 ml of the oil to be titrated.
5. Now, filling the eyedropper with exactly 1 ml of 0.1% lye solution, start dripping this solution into the medicine measure while stirring.
6. Keep track of how many ml of 0.1% lye solution are needed for the liquid to turn and stay red.

The number of millilitres of 0.1% lye solution needed is equal to the number of extra grams of pure sodium hydroxide catalyst needed to produce the proper reactions to make biodiesel. For example, if it takes 3 ml of 0.1% lye solution to turn the oil and isopropyl alcohol solution to a base, you will need to add 3 grams of sodium hydroxide to the 3.5 grams for new oil, or 6.5 grams total per litre of waste oil.

The Process Start with ten litres of waste oil, two litres of methanol and 50 grams of caustic soda (or the exact amount if you have carried out a titration as above). Add the caustic soda to the methanol until it is dissolved. Add the resulting sodium methoxide into the waste oil. Stir for one hour. You can use an electric mixer or a sump pump for this stirring process. After mixing is complete, allow the mixture to settle overnight. Then siphon off or pump out the biodiesel from the top of the container. Wash the biodiesel by spraying water at a low velocity on top of a tall column of biodiesel. The water will wash away any excess alcohol and catalyst. It will emulsify with the biodiesel so the less this mixture is agitated the better, as agitation will cause more emulsification and poorer quality biodiesel. Let this mixture sit for 24-48 hours until the water has settled and then run it through a fuel filter before adding to your diesel fuel tank.

Larger scale Biodiesel Production

Raw Materials

For the oil, you may use new, de-gummed vegetable oil. If you are a farmer, you can press and de-gum your own oil. If not, you can buy pressed raw oil.

Industrial biodiesel process

Raw materials

These are the typical quantities of raw materials and chemicals to produce 1,000 kg of biodiesel and 112 kg of glycerol. Refined vegetable oil – 1030 kg. Methanol – 102 kg. Catalyst (sodium methylate) – 6.2 kg. Mineral acid – 6 kg

Batch processing is convenient for small productions of less than 10,000 t/year. Larger production levels call for a continuous machines where the reaction and distillation of the alcohol is a batch processing and the decantation is continuous.

1. The base of methanol and vegetable oil are mixed in a static mixer.
2. In the reactor, esterification of the free fatty acids occurs.
3. In the second static mixer, a catalyst is added to the methanol-oil mix for the transesterification.
4. Transesterification takes place in the second reactor.
5. The product of the reaction (biodiesel, glycerol and methanol solvent) are neutralised by adding a mineral acid in the third mixer.
6. The alcohol is separated in the flash vaporizer or distillation unit. The vapours of methanol are condensed and sent to the reception unit to be introduced again in the cycle.
7. The remaining products in the flash vaporizer (biodiesel, glycerol, salts and water) are sent to a continuous decanter, to separate the biodiesel from the rest of the byproducts. The light phase (biodiesel) of the solution in the decanter is sent to the storage tank and the heavy phase (90% pure glycerol, water and salts) is sent to another storage tank for later purification.

Glycerol is a marketable byproduct of the biodiesel transesterification process. The equivalent product to biodiesel-glycerol is synthetic glycerol that is petrochemically-produced and liable to increase in price as oil prices climb.

Biodiesel Benefits

Within minutes of biodiesel being added to the fuel tank, and especially when used in high blend ratios (50% to 100%) a reduction in engine noise will be noticed. The engine will operate more smoothly but with a distinct change in the smell of the exhaust sometimes described as a smell of popcorn. The longer the biodiesel is run in the engine, the better is the performance. Research has been done comparing biodiesel to petrodiesel across a wide range of parameters. One of the most significant differences is the drastic reduction in tailpipe emissions biodiesel produces over petrodiesel. Reductions in hydrocarbons, carbon dioxide, and particulate matter are significant. For many people that use biodiesel, these reductions in emission nasties are sufficient reason to use this alternative fuel. Besides reduced emissions, research has indicated an increase in engine longevity, a decrease in engine maintenance, and better engine performance.

Engine Modifications

If you start using biodiesel regularly, it is wise to use a diesel fuel filter/water separator with any diesel engine. These are available through some auto parts stores. The other problem is that biodiesel has a solvent effect. It may dissolve some old residues and these will clog your fuel filter. If you change your fuel filter regularly when first using biodiesel, that should not prove a problem. You may have a problem with natural rubber hoses and seals made prior to 1992. The biodiesel may degrade these types of rubber and they will need to be replaced. Newer diesel engines have polymer hoses and seals, using polymer materials like Viton and these will work fine with biodiesel. Since most diesel injector pumps don’t have rubber parts directly in contact with the fuel, it is relatively easy to replace just the hoses and seals. A fuel mixture of 20% biodiesel and 80% petroleum diesel will have no effect on older natural rubber hoses.

Biodiesel Problems

The temperature at which the fuel will no longer pour is called the pour point or gel point. Biodiesel has a higher pour point than petroleum diesel (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, but biodiesel made from sunflower or rapeseed oil will have a lower pour point.

Biodiesel will go cloudy at temperatures below 13 degrees C. While this clouding is easily reversed by raising the temperature of the fuel back above 13 degrees, it may cause temporary clogging of your fuel system and stop your engine. Petroleum diesel fuel can be used down to minus 24 degrees C. It is a good idea to use a blend of at least 50% petroleum diesel with your biodiesel, if you are going to be operating in cold weather.

Additives to petrodiesel can lower the gelling temperature, but there are no such additives for biodiesel. You can experiment with different blends of biodiesel and petroleum diesel to determine what works best for you. Simply mix up batches of fuel with different ratios of petroleum diesel and biodiesel in glass jars and put in a freezer. Use a thermometer to determine the temperature of the fuel. Periodically check on the fuel to determine at what temperature it gets cloudy. This temperature is the “cloud point”. It is best to determine this point at home before you head out on the road and get stranded in a snowstorm because your mixture is too rich in biodiesel. Of course, if you are going to be operating during the warm months, or in the northern parts of the country, you can use 100% biodiesel with no problems.

Using Vegetable Oil as Diesel Fuel

You can also modify your car so that it can run on biodiesel in the winter and the same modification will allow you to run the vehicle on unmodified vegetable oil during the summer. The basic system is to install an extra fuel tank, heated by coolant from the engine. The vehicle is started on a non-gelling fuel (petrol in winter, biodiesel in summer) and then you switch to the gellable fuel after it has been heated.

The basic modification involves fitting a fifty litre tank into the boot of your car. The first step is to obtain all the various hoses, fittings, and other parts necessary for the conversion. Then take 8 metres of 1 cm flexible copper pipe and bend it using a tubing bender to fit as much of it into our tank as possible. This makes a heat exchanger and hot coolant from the engine will run through it to heat the fuel in the tank.

You can build a cardboard model of the eventual fuel tank as this is very helpful. You need to connect the copper coil to the model using two bulkhead fittings. Holes for the fuel filler plate and the fuel level gauge are then made on the cardboard model. Test the model in the trunk to make sure there is clearance for all hoses and connections. Then take the tank model to your local engineering workshop and get them to make an aluminium version and add on brackets to secure it to the vehicle.

Get them to install the tank in the boot and run the coolant hoses from the engine compartment under the car and into the tank. Connect the coolant hoses in the engine to the hoses running to the heater core (the device which heats the passenger compartment). To keep the fuel warm from the boot to the engine, the fuel line runs in a “pipe within a pipe.” The inner pipe holds the fuel; the outer pipe has the hot coolant. Dont use polyethylene as it not rated to withstand temperatures above 100C so you must use copper tubing.

In the engine compartment the fuel line connects to a solenoid switch which allows switching between two fuel tanks with a toggle switch on the dashboard. After the solenoid, install two fuel filters, one at 30 microns and the other at 10 microns. The second fuel filter has a special coolant-based heater built into it to give the fuel one last burst of heat before going to the engine (this feature is only necessary for vegetable oil fuel and is not necessary if you are just using biodiesel.)

In the boot, install a fuel temperature gauge and a thermoswitch. The thermoswitch should be wired in series with the solenoid switch, and will prevent you from trying to use the heated tank before it is hot enough. All the wiring for the gauges and switches should be run to the dashboard, and positioned to the right of the steering wheel. You should set the fuel level gauge on top, a fuel temperature gauge below, and the toggle switch for the solenoid.

How It Works

On a cold day, you start the car on the main tank, which has a non-gelling blend of biodiesel and petrodiesel. When the car is going, flip the switch to the heated tank and start driving. After about ten km, if on biodiesel, the fuel in the heated tank is warm enough and the thermoswitch engages, allowing the engine to take fuel from the heated tank. About ten km from the end of your drive, switch back to the main tank to purge the fuel lines of any gellable fuel.

The above process may seem too difficult for the average lifestyle block holder but the use of biodiesel is much more straightforward and worth considering from both an economic and environmental point of view.

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