BIO DIESEL A fuel for future
Introduction of biodiesel
• Alternative fuel for diesel oil
• Made from vegetable oil or animal fat
• Meets health effect testing
• Lower emissions, high flash point, safer
• Biodegradable, non toxic
• Miscible with petro diesel in all ratios
History of biodiesel
• Investigated as diesel fuels before the energy crisis of the 1970s and early 1980s
• Rudolf diesel: inventor of diesel engine
• French Otto company in 1900 operated a small diesel engine on peanut oil
• Gained little attention due to widespread availability and low cost of petroleum diesel fuel
How diesel engine works
• Fuel is ignited by hot air; the air is heated by compression
• Ignition should begin as soon as possible.
• If it does not, the entire charge of fuel become thoroughly mixed with air, and when it does ignite, the pressure rise will be much steeper than it would have been had ignition occurred earlier.
• So a desirable property of a diesel fuel is that it ignite quickly.
• Four methods to reduce the high viscosity: blending with petro diesel, pyrolysis, micro emulsification and transesterification
• Only transesterification reaction lead to the formation of bio diesel
• Transesterification can proceed by base or acid catalysis
• In homogeneous catalysis, alkali catalysis is a much more rapid process than acid catalysis
Chemistry of Triglycerides
• It is a reversible reaction
• Pseudo-first-order or second-order kinetics, depending on the molar ratio of alcohol to oil, the reverse reaction is second order.
•For transesterification to give maximum yield, the alcohol should be free of moisture and the FFA content of the oil should be <0.5%.
• Standard parameters for methanol based transesterification are 60°C reaction temperature and 6:1 methanol: oil molar ratio
Typical lipid feed stocks are refined vegetable oils
I.Rapeseed and sunflower oils are used in the European Union
II. Palm oil predominates in biodiesel production in tropical countries
III. Soybean oil and animal fats is the major feed stocks in the United States
• Much cleaner than conventional fossil fuel
• Reduces unburned hydrocarbons (93% less), carbon monoxide (50% less) and particulate matter (30% less) in exhaust fumes, as well as cancer-causing PAH (80% less) and nitrated PAH compounds (90% less)
• Sulphur dioxide emissions are eliminated
Recipe to make Biodiesel
• Bio-diesel blending in Diesel improves most of the Fuel properties
• Mass emissions of carbon monoxide and particulates found lower with Biodiesel blends, but NOx increased
• Due to low energy content, high fuel consumption
• Its Price is higher, hence not in practiced