Biodiesel Production

Biodiesel Production and Equipment

Biodiesel production is the process of blending pure biodiesel, commonly called B100 (for 100 percent), with standard petroleum-based diesel fuel, to create varying grades of fuel for diesel engines. There are quite a few reputable suppliers in many states that manufacture and sell the B100 pure biodiesel. When selecting your supplier, you need to know what oil the biodiesel was made from, to know the likely characteristics, particularly in cold conditions. The better choices are canola, sunflower or corn; the less saturated an oil, the better for cold conditions, and combustibility.

To start your own biodiesel production in a 55 gallon tank, you need at least three 55 gallon tanks, one for the pure biodiesel, one for the standard petroleum-based diesel fuel, and an empty tank for the blending process. Acceptable storage tank materials are fluorinated polyethylene, fluorinated polypropylene or Teflon. The tanks for the biodiesel storage and the blending should be as clean as possible, perhaps a little used diesel storage tank, because biodiesel is a great cleaner and it will strip any remaining diesel or dirt from the tank walls. For storage, it is advisable to adopt the normal storage requirements of petroleum-based diesel for biodiesel as well, whether blended or pure. Care must be taken with the standard petroleum based diesel because it has a low flashpoint of 125 F (51C). The biodiesel flashpoint is 300F (149C) which is relatively safe for most situations. NB The lower the percentage of biodiesel in a blend, the lower the flash point! Speak to your local safety officer or fire chief.

All three drums being used for biodiesel production should kept in a clean, dry and shadowed or darkened area, preferably inside for colder temperatures, the pure biodiesel, particularly, does not like condensation or moisture, which can allow mold or algae to grow. Storage is important for cold working as well. Pure biodiesel will gel at zero degrees, but your blend should give you a bit more latitude. There are additives one can get to help the flow of biodiesel in very low temperatures.

Standard blends for use in standard diesel engines are anywhere from 2% to 20% biodiesel with the complementary amount of petroleum-based diesel fuel. For B20 (20% biodiesel 80% standard diesel fuel) the ratio of biodiesel to petroleum based diesel fuel is 1 to 4. There are now some people making a 50% blend but there are considerations when using this blend in a standard diesel motor vehicle, which we’ll come to later.

The accuracy of the blend is very important and so is the mixing. Because of the difference between the natural viscosity of biodiesel and normal petroleum based diesel fuel, it is best to put the required quantity of petroleum diesel fuel in first, and add the biodiesel to it. The biodiesel is heavier and more viscous than the diesel fuel, and putting it in second facilitates the mixing process, because being heavier it will sink to the bottom, automatically mixing. Sufficient agitation or mixing should be done to have a thorough mix. You can test for satisfactory results by doing a layer test, taking a sample from the bottom, middle and top of the tank respectively, and placing all three samples in a freezer. You then keep checking for crystallization, the cloud point. If they all exhibit crystallization at about the same temperature, you have a good blend.

It is very common to use air operated agitators in biodiesel production. Diesel is flammable fluid, so an air motor provides an intrinsically safe non sparking mixer motor which is acceptable for most explosion proof applications. An air agitator speed can be simple adjusted by controlling the air flow, so this gives you good blending and process control depending on the liquid level and viscosity in the drum. Mixer providers like www.wmprocess.com do offer explosion proof electric operated mixers, these are generally more heavy and more expensive than air operated.

Air mixers do come in a variety of mounting arrangements including C clamp mount, drum lid mount, drum bung 2” NPT mounting and a bridge or bracket mounting arrangements. There are also a variety of drum impellers that can be used, including folding props, stainless steel impellers and plastic impellers like Teflon, PFA, Kynar PVDF, Polypropylene, and Polyethylene.

Now that you have your blend, there are some considerations for dispensing your fuel. Any blend up to 50%, B50, will generally flow down to zero degrees. If you are expecting to be operating at temperatures below that, then you will need to invest in heating equipment for tanks and supply lines. In extremely cold conditions, there may be some separation in the tank. In that case just draw the lighter fuel from the top of the tank for use in these temperatures.

MIX TANKS AND AGITATORS FOR BIOFUELS AND BIOMASS PROCESSES

• Biodiesel Mixers
• Bioreactor Tank and Agitator
• Biomass Fermentation and Storage Tank Mixers
• Culture Mixing Tanks
• Biofuel Blending Agitated Vessels
• Biochemical Mixtanks
• Digester Vessels
• Fuel Oil Mixing and Blending
• Green mixing technologies for pesticides and agriculture chemistries

We offer TOP ENTRY MIXERS, BOTTOM ENTRY MIXERS, and SIDE ENTRY AGITATORS depending on your process requirements. LOW SHEAR MIXING and HIGH SHEAR HOMOGENIZING systems available to suit.