Re: Ethanol and CO2


"JazzMan" <No_Spam@xxxxxxxxxxx> wrote in message
news:43F73C03.C0D@xxxxxxxxxxxxxx

Looked at in another way, energy in fuels like gasoline
and ethanol is stored in carbon bonds.

Agree mostly. Energy comes from reaction of hydrogen in the fuels with
oxygen
to give water and energy, and reaction of carbon with oxygen to give CO2 and
energy.

The hydrogen oxidation is the most energetic part of the equation. Hydrogen
as a fuel would be good with respect to the environment if it could be
produced
and stored.

Don, if you want quantitative answers, the link I posted to you will give
you
some of it. You will have to do a complete materials and energy balance to
get to the bottom line however. You will likely have to have fuel to
cultivate the
crops which lead to ethanol production, to harvest them, to prepare them, to
distill them, etc. The fate of the waste products might have to be factored
in.
(Are you going to feed the waste mash to horses or mules to cultivate the
crops,
or are you going to use a John Deere?)

Cows, horses, people, and bacteria produce methane from metabolism of some
of these crops, and methane is also a greenhouse gas. If you recovered it
in a
digester, you could compress it and use it for fuel too.

In chemistry of this sort, the total path needs to be accounted for, as I am
sure you understand. That is one of the reasons there is so much
controversy..
the path is not totally clear.


.

Relevant Pages

  • Re: Low Cost Hydrogen is here to stay
    ... This library page holds a collection of hydrogen energy resources. ... But please do NOT call Hydrogen a fuel. ... one MIGHT foolishly object and say that oil coal and natural gas ... water down into its component parts and retain the hydrogen, ...
    (sci.energy.hydrogen)
  • Re: ETHANOL OR METHANOL?
    ... An Energy Revolution ... The world economy is currently running on a resource that is ... percent fuel saving over existing models, and none of them drove more, ... THE ECONOMICS AND TECHNOLOGY HAVE ARRIVED?NOW FOR THE POLITICS ...
    (sci.energy)
  • Why We Need The Solar-Hydrogen Economy Now
    ... chemical engineer and nuclear engineer. ... Today's energy systems did not arise ... Fuel combustion from automobiles and power plants is the primary source ...
    (sci.energy)
  • Why We Need The Solar-Hydrogen Economy Now
    ... chemical engineer and nuclear engineer. ... Today's energy systems did not arise ... Fuel combustion from automobiles and power plants is the primary source ...
    (sci.energy)
  • Re: reformation of CO2 into gasoline
    ... > Does anybody know if the combustion of any hydrocarbon fuel in ... > and gasoline specifically can be reversed with the input of energy? ... Tropsch reaction over cobalt catalysts will produce hydrocarbones ... > energy input was reasonable, this would be more attractive than using ...
    (sci.energy)