Re: reformation of CO2 into gasoline
bernxard_at_yahoo.com.au
Date: 02/22/05
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Date: 21 Feb 2005 20:20:14 -0800
jojocrazypa...@yahoo.com wrote:
> Does anybody know if the combustion of any hydrocarbon fuel in
general
> and gasoline specifically can be reversed with the input of energy?
> Has a process been developed to do this? If the chemical equation
for
> the combustion of isooctane is:
>
> 2 C8H18 + 25 O2 => 16 CO2 + 18 H2O + energy
>
> than has a process been developed to generate the following reaction:
>
> 16 CO2 + 18 H2O + energy = 2 C8H18 + 25 O2
The process can be accomplised indirectly. Forms of the Fischer
Tropsch reaction over cobalt catalysts will produce hydrocarbones
mainly diesel. The reaction is however:
nCO2 + (3n+2)H2 -> nCH2 + 2nH2O and is exothermic. It is better at
producing diesel than gasoline and has been considered by a German
institute called ZSW from synthesising fuel from CO2/air and
electrolytic hydrogen. The overall proecess was around 44% efficient.
There is also the Lurgi Reaction over copper/zink.
CO2+3H2 -> CH3OH + CO2. The Methanol can be converted to gasoline via
the MTG (Methanol To Gasoline Process).
Ethanol can also be made by a similar reaction using molydenum sulphite
instead of copper/zink. There is also an ETG process.
There is also the Sabatir reaction
CO2 + 4H2 -> CH4 + 2H20 (ie methane)
>
> How efficient is this process?
I believe the German ZSW process was 38% if faily inefficient (70%)
alkalyne electroysers were used and if the CO2 was extracted from the
air. If high termperature electrolysis was used then 60% could
theoretically be achieved: perhaps more but I thnk state of the art now
would be around 44%.
Inmdeed they said that the costs of compression or liqifaction are
enormous. Electrolysis plus compression is around 65% efficient and
Electrolysis with liquifaction around 57%
It seems to me that if the amount of
> energy input was reasonable, this would be more attractive than using
> hydrogen as a way to store energy for use by a powered vehicle. The
> whole "hydrogen economy" idea hinges on using either fossil fuels as
> the initial energy source (accomplishing essentially nothing), or
> renewable energy. Either way there are the significant problems of
> distribution and storage on the vehicle itself and development of
fuel
> cells.
>
> Can we use our existing infrastructure and fleet of vehicles and
> produce fuel with renewable energy? If we can obtain the CO2 for the
> reaction by scrubbing the atmoshphere then we can make the use of
> gasoline a global warming neutral proposition (at least for the
portion
> of fuel that we produce from renewable sources).
- Previous message: bw: "Re: reformation of CO2 into gasoline"
- In reply to: jojocrazypants_at_yahoo.com: "reformation of CO2 into gasoline"
- Next in thread: Eric Gisin: "Re: reformation of CO2 into gasoline"
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