In the interest of ease of use for the biodiesel
home brewer, this chapter describes the basecatalyzed
production method using methanol
and sodium hydroxide. The products of transesterification
are methyl ester (used as fuel)
and glycerin (soap). About 20 percent of vegetable
oil is glycerin, which will be removed during
the chemical process and replaced with alcohol.
You’ll need a plan to dispose of the waste so you
don’t end up with dozens of plastic pails full of
glycerin scattered around the yard.
Benefits and Drawbacks:
Using biodiesel instead of fossil diesel presents many benefits to both environment and engine, but it’s not without quirks and peculiarities. All of these need to be addressed to achieve success in using biodiesel as a fuel.
Benefits :
Biodiesel biodegrades about four times faster than fossil diesel. Its lack of sulfur eliminates the sulfur oxides (responsible for acid rain) produced when fossil diesel is burned. Because biodiesel is an oxygenated fuel containing 11 percent oxygen by weight, combustion is more complete and overall emissions are reduced by up to 90 percent when B100 (100-percent biodiesel) is used instead of fossil diesel. These emissions include carbon monoxide, carbon dioxide, unburned hydrocarbons, and particulate matter (soot).
Oxygen content in fuels effectively increases the volumetric efficiency of the engine as a result of more complete fuel combustion. This increase in combustion efficiency helps overcome the slightly lower energy content of biodiesel: You may not notice a significant difference in engine performance or fuel economy when using B100, but you can expect to experience some loss of each. Biodiesel’s higher cetane number (a measure of the fuel’s ability to ignite under pressure) translates to better fuel ignition. Increased lubricity means less wear and tear on engine and fuel system components, and it has a detergent effect on the entire fuel system.
Biodiesel is produced from recently grown biomass, rather than biomass that grew millions of years ago and has remained sequestered for that time (as is the case with fossil fuels). Therefore, no net increase in atmospheric carbon dioxide (CO2) results from burning biodiesel because the same amount of carbon dioxide is released when that biomass decays naturally. Of course, in most cases, producing biodiesel requires the use of fossil diesel, but a net CO2 reduction of over 75 percent can be realized when using B100. Finally, tailpipe emissions smell like fried food, which is considered a benefit by most people driving behind a biodiesel-powered vehicle.
Drawbacks:
Shortcomings of biodiesel include a possible increase in nitrogen oxides (NOx) when burned, depending on the type of engine. Nitrogen oxides contribute to smog and ozone. Given the lower energy content of biodiesel, you may experience a 10-percent reduction in fuel economy if you’re driving on B100. Biodiesel will dissolve any rubber in the fuel system, such as gaskets or seals, so all rubber parts that may come into contact with biodiesel must be replaced with synthetic materials.
Biodiesel has some cold-weather limitations. It begins to congeal (reaches its gel point) at around 45°F and must be mixed with fossil diesel when the temperature drops below this gel point; see Mixing Biodiesel with Other Fuels on page 204. Be aware that biodiesel acts as a solvent that will dissolve the fossil diesel deposits that have accumulated inside of your fuel tank and filter. Ideally, you should flush the fuel tank with a few gallons of biodiesel (let it sit for a day or so), drain, and repeat, until all of the gunk is gone. You should also replace the fuel filter after flushing the tank. If you don’t flush the fuel tank, you’ll quickly go through several fuel filters, as they will become clogged with sludge. Biodiesel will leave its own residue in the fuel tank that will build up over time. Should you switch back to fossil diesel after using biodiesel for a while, flushing the tank may again be needed.
Benefits and Drawbacks:
Using biodiesel instead of fossil diesel presents many benefits to both environment and engine, but it’s not without quirks and peculiarities. All of these need to be addressed to achieve success in using biodiesel as a fuel.
Benefits :
Biodiesel biodegrades about four times faster than fossil diesel. Its lack of sulfur eliminates the sulfur oxides (responsible for acid rain) produced when fossil diesel is burned. Because biodiesel is an oxygenated fuel containing 11 percent oxygen by weight, combustion is more complete and overall emissions are reduced by up to 90 percent when B100 (100-percent biodiesel) is used instead of fossil diesel. These emissions include carbon monoxide, carbon dioxide, unburned hydrocarbons, and particulate matter (soot).
Oxygen content in fuels effectively increases the volumetric efficiency of the engine as a result of more complete fuel combustion. This increase in combustion efficiency helps overcome the slightly lower energy content of biodiesel: You may not notice a significant difference in engine performance or fuel economy when using B100, but you can expect to experience some loss of each. Biodiesel’s higher cetane number (a measure of the fuel’s ability to ignite under pressure) translates to better fuel ignition. Increased lubricity means less wear and tear on engine and fuel system components, and it has a detergent effect on the entire fuel system.
Biodiesel is produced from recently grown biomass, rather than biomass that grew millions of years ago and has remained sequestered for that time (as is the case with fossil fuels). Therefore, no net increase in atmospheric carbon dioxide (CO2) results from burning biodiesel because the same amount of carbon dioxide is released when that biomass decays naturally. Of course, in most cases, producing biodiesel requires the use of fossil diesel, but a net CO2 reduction of over 75 percent can be realized when using B100. Finally, tailpipe emissions smell like fried food, which is considered a benefit by most people driving behind a biodiesel-powered vehicle.
Drawbacks:
Shortcomings of biodiesel include a possible increase in nitrogen oxides (NOx) when burned, depending on the type of engine. Nitrogen oxides contribute to smog and ozone. Given the lower energy content of biodiesel, you may experience a 10-percent reduction in fuel economy if you’re driving on B100. Biodiesel will dissolve any rubber in the fuel system, such as gaskets or seals, so all rubber parts that may come into contact with biodiesel must be replaced with synthetic materials.
Biodiesel has some cold-weather limitations. It begins to congeal (reaches its gel point) at around 45°F and must be mixed with fossil diesel when the temperature drops below this gel point; see Mixing Biodiesel with Other Fuels on page 204. Be aware that biodiesel acts as a solvent that will dissolve the fossil diesel deposits that have accumulated inside of your fuel tank and filter. Ideally, you should flush the fuel tank with a few gallons of biodiesel (let it sit for a day or so), drain, and repeat, until all of the gunk is gone. You should also replace the fuel filter after flushing the tank. If you don’t flush the fuel tank, you’ll quickly go through several fuel filters, as they will become clogged with sludge. Biodiesel will leave its own residue in the fuel tank that will build up over time. Should you switch back to fossil diesel after using biodiesel for a while, flushing the tank may again be needed.
