How can ethanol be used as a biofuel?

Well first it has to be made from biological sources, usually the fermentation of sugars and starches from plants. If the ethanol is made from high temperature Fischer Tropsch from the gasification of natural gas, coal or heavy oils then it’s still a fossil fuel, if it’s from the gasification of biomass then it’s a bio fuel. Of course the equipment needed for synthesis of ethanol or methanol is the same equipment needed for synthesis of gasoline and diesel and is expensive so most ethanol is made by biological processes like fermentation. Note that fermentation takes energy, particularly from starches which have to be first broken down into sugars and if the energy is from fossil sources then even ethanol from biological sources would still be fossil fuel. Specifically, to produce one gallon of corn ethanol, it takes the energy equivalent of 0.8 gallons of gasoline and corn ethanol only has 2/3 the energy of the same volume of gasoline so with corn ethanol, you’re burning the equivalent of 1.2 gallons of gasoline in fossil fuel to get a 1 gallon of gasoline equivalent energy in ethanol.

To use ethanol, you use it in a gasoline engine with the fuel air ratio adjusted to account for the lower energy density, ie.: increase the rate that the fuel is injected into the engine. The difference between a regular modern car and a flex fuel car is that the computer chip on the flex fuel car is programmed to allow for gasoline that’s up to 85% ethanol (probably programmed for up to 95% to be on the safe side) whereas the regular car would only be programmed for up to 15% ethanol (probably up to 35% to be on the safe side), likewise the fuel injectors are sized appropriately and the fuel lines, fuel filter, seals and fittings on the flex fuel cars would be more resistant to ethanol. The fuel filter needs to be larger cause every time you go from using mostly gasoline to using mostly ethanol, some varnish and debris from the gasoline gets loosened up and can clog the fuel filter.

3 Responses

Blame Bush says:

July 30, 2010 at 9:39 am

You should walk or Bike. Ethanol still warms the globe with CO2

Stop biofuel alternatives. Be TRUE green!
peter.jungmann says:

July 30, 2010 at 9:58 am

You use it as a fuel like gasoline.

(And ruin your engine, pollute more than using oil, and starve poor children all around the globe by making corn so expenisve they can’t eat.)
John W says:

July 30, 2010 at 10:01 am

Well first it has to be made from biological sources, usually the fermentation of sugars and starches from plants. If the ethanol is made from high temperature Fischer Tropsch from the gasification of natural gas, coal or heavy oils then it’s still a fossil fuel, if it’s from the gasification of biomass then it’s a bio fuel. Of course the equipment needed for synthesis of ethanol or methanol is the same equipment needed for synthesis of gasoline and diesel and is expensive so most ethanol is made by biological processes like fermentation. Note that fermentation takes energy, particularly from starches which have to be first broken down into sugars and if the energy is from fossil sources then even ethanol from biological sources would still be fossil fuel. Specifically, to produce one gallon of corn ethanol, it takes the energy equivalent of 0.8 gallons of gasoline and corn ethanol only has 2/3 the energy of the same volume of gasoline so with corn ethanol, you’re burning the equivalent of 1.2 gallons of gasoline in fossil fuel to get a 1 gallon of gasoline equivalent energy in ethanol.

To use ethanol, you use it in a gasoline engine with the fuel air ratio adjusted to account for the lower energy density, ie.: increase the rate that the fuel is injected into the engine. The difference between a regular modern car and a flex fuel car is that the computer chip on the flex fuel car is programmed to allow for gasoline that’s up to 85% ethanol (probably programmed for up to 95% to be on the safe side) whereas the regular car would only be programmed for up to 15% ethanol (probably up to 35% to be on the safe side), likewise the fuel injectors are sized appropriately and the fuel lines, fuel filter, seals and fittings on the flex fuel cars would be more resistant to ethanol. The fuel filter needs to be larger cause every time you go from using mostly gasoline to using mostly ethanol, some varnish and debris from the gasoline gets loosened up and can clog the fuel filter.

Popular Phrases

Categories

3 Responses

How can ethanol be used as a biofuel?