Biomedical Engineering Reference
In-Depth Information
16
14
12
10
8
6
4
2
0
Inedible
Tallow
Yellow
grease
1
Canola
Soybean
Recyle oil
(1)
Diesel
Yellow
grease
2
Recyle oil
(2)
Edible
Tallow
Lard
Figure 3. Increase in NOx emissions from CI engines using various B100 fuels.
1.3. Benefits of Biodiesel: Environment
As stated earlier, biodiesel is derived from renewable sources such as vegetable oils,
animal fats, and waste cooking oils. Once produced and used, the byproducts of its
combustion in automobile engines are carbon dioxide and water only. The source of
biodiesel, such as soybeans, will absorb CO
2
during its lifetime through photosynthesis. In
this way, biodiesel is considered carbon neutral. However, when production is considered,
biodiesel is not neutral. Fossil fuels are still required to create the steam, electricity, and
methanol needed for manufacturing, and to fuel the equipment for farming and
transportation and materials. Even with all this fossil fuel input, biodiesel is still an energy
efficient fuel. From one unit of fossil fuel energy used to produce the biodiesel, 3.2 units of
energy are created as biodiesel fuel [4]. It is also estimated that biodiesel still has 41% less
carbon dioxide emissions than petroleum based diesel [2]. Biodiesel also reduces other
emissions such as particulate matter, hydrocarbons, and carbon monoxide. This is due to
the 11% oxygen by weight content that allows for more complete combustion. [4]
Furthermore, biodiesel is a natural substance and therefore is biodegradable if spilled. It is
also comparably better than other popular renewable energies. Soybean based biodiesel has
a 93% energy gain compared to only 25% for corn derived ethanol [5]. An 80000-km
durability test was performed on two engines using diesel and biodiesel (methyl ester of
waste cooking oil) as fuel in order to examine emissions resulting from the use of biodiesel
