alt.energy.renewable

wrote in message
news:4bd0fdf5-5b2d-40fe-830c-6a9dadd98a12@q33g2000hsh.googlegroups.com...
On Feb 19, 8:51 pm, danny burstein wrote:
> In nicksans...@ece.villanova.edu
> writes:
> >=?iso-8859-1?Q?Roland_M=F6sl?= wrote:
> >>"patrick mitchel" schrieb im Newsbeitrag:
> >>> Hell; I've been to 3 sites and they have different #'s as to the
> >>> pounds
> >>> of carbon dioxide produced in the burning of a gallon of gasoline. And
> >>> the
> >>> method as to how they arrived at the figure? Thanks Pat
>
> >>1 Litre makes 2,365 kg CO2
> >Wow. Perhaps you mean 2.365. The USEPA says a gallon makes 19.4 pounds.
>
> here's something I put together a few years ago:
>
> Date: Tue, 29 Oct 2002 01:37:07 +0000 (UTC)
> Subject: Re: Creating 25 lbs of CO2
>
> Ah, for high school chem and physics.
>
> Ok, first we have to define gasoline. let's keep it simple and just use
> the single octane molecule ( C8H18) and not worry about the rest.
>
> And let's also figure on complete combustion with all the carbon burning
> into CO2 and not into other things.


>
> Next step is to figure how many molecules of octane we have. Well, a
> gallon of gasoline weighs about 6.2 pounds [a].
>
> next is to figure how much of that is carbon versus hydrogen
> (keeping it simple, and using atomic weights of 1 for hydrogen
> and 12 for carbon)
> 8 carbons * 12 = 96
> 18 hydrog * 01 = 18
> total molecular weight of octane: 114
> percent that is carbon: 96/114 = 0.84 = 84%.
> and multiplying that by 6.2 pounds -> 5.22 pounds of carbon/gallon
>
> next step:
> 5.22 pounds of carbon -> ??? pounds of CO2 ?
> again, let's keep this simple and use 16 for oxygen's atomic weight.
>
> So... in a molecule of CO2, the total moleculer weight is:
> 12 (from carbon) plus 32 (from two oxygen atoms)
> totalling: 48.
>
> Since the atom of carbon was 12, that means that a molecule of CO2,
> being 48, is four times as great.
> HENCE, one gallon of gasoline, which has 5.22 pounds of carbon,
> will give you 20.88 pounds of CO2
>
> [a]http://www.sheboygan.lib.wi.us/pages/reffaq3.html(among many others)
>
> --
> _____________________________________________________
> Knowledge may be power, but communications is the key
> dan...@panix.com
> [to foil spammers, my address has been double rot-13 encoded]

Very good except 12+32=44. Using that 19.14 which is closer to the
19.4 given. Use a longer molecule like C14H30 and you get 19.3 We
know the average length is longer than octane because longer molecules
break up easier and are more likely to cause detonation, and pump
gasoline is generally lower than 100 octane.

Bruce
----------------------------------------------------------------
The original figure of 2,365 kg CO2 per liter is apparently (considering the
source) is in European format where the decimal point is represented by a
comma so that in North American notation, it is 2.365 kg. Hence there is no
error except in interpretation of notation.

Actually, the correct number is likely about 2 +/- 0.5 kg/liter (about 20
lb/us Gallon) due to the difference between theoretical results and actual
results caused by completeness of burning and differences in composition of
different gasolines (Daestrom pointed this out). The extra decimal values
are nice but generally meaningless.


--

Don Kelly dhky@shawcross.ca
remove the X to answer
----------------------------