14-03-2012, 02:23 PM
Biofuels For the Global Environment
ENVIRONMENTAL ATTRIBUTES OF BIODIESEL
[attachment=18319]
Emissions Reduction
Substantial reduction of unburned HC, CO,PAH and particulate matter.
Particulate matter produced from biodiesel consumption is less toxic
and have less mutagenic potential than the conventional diesel emission
Consumption of the biodiesel also reduces the soot production in
comparison of the diesel
Also,the use of biodiesel reduces CO2 in the atmosphere, for example
growing soybean consumes nearly four times as much CO2 as the
amount of CO2 produced from the biodiesel exhaust.
The esters are advantages over diesel fuels as they are free from
sulfur.The combustion of oil esters in engine will not produce acidic
sulfur oxides
ENERGY BALANCE
Biodiesel helps preserve and protect natural resources.
For every one unit of energy spent to produce biodiesel 3.24 units of energy are gained.This is the highest energy balance of any fuel.
Because of high energy balance and domestically produced, biodiesel use can greatly contribute for the domestic energy security.
Flash point & Fire point
It is a measure of volatile property and flammability.
It is used to classify flammable liquids and therefore affects the design of equipment and the control of potential ignition sources.
Fire point is minimum temperature (usually 5oC higher than the flash point) at which an oil gives off sufficient vapor which when ignited continue to burn for at least 5 seconds is known as fire point of the oil.
Flash point and fire point are helpful in providing safeguard against fire hazards during their storage, transportation, handling,and use.
Significance of CN
A higher CN reduces ignition delay and results in smoother combustion and lower combustion noise.
It also improves the cold starting of diesel engines. An increase in CN produces a decrease in NOx emissions due to lower gas temperatures and pressures in the combustion chamber.
Reductions in CO and HC emissions have also been reported.
These benefits are less marked in new engine designs. However benefits are not generally achieved above a CN of about 50.
