..............


>> from water.  Carbon based fuels are more convenient to our current 
>> infrastructure.  I've always been intrigued by the idea of taking 
>> water and grabbing CO2 out of the air to make a carbon based fuel, 
>> like methane or methanol for example.  I think the real problem is 
>> that there is so little carbon in the air, that concentrating it will 
>> be inefficient.  Still, there is nothing theoretical against this that 
>> I can see, and the low fraction of carbon in the air makes it 
>> difficult but does not require it to be theoretically inefficient, 
>> although you have to harness the energy represented in the "waste" 
>> oxygen that will be produced.  I know this is totally impractical 
>> today, but I wonder how feasible it could be if there was a concerted 
>> effort to make it so.
>
>Wow! Now that is interesting... Where does CO2 (as in fire extinguishers,
>dry ice, etc... Come from now?) Pulling it out of the air could help to
>reverse global warming as well, right?
>

I've thought about that too. The last I looked on the net, CO2 is a waste product in many industries, no need to go making it yourself.

"The Fischer-Tropsch process is a catalyzed chemical reaction in which carbon monoxide and hydrogen are converted into liquid hydrocarbons of various forms. Typical catalysts used are based on iron and cobalt. The principal purpose of this process is to produce a synthetic petroleum substitute."

Sasol in South Africa has been doing this for decades, using coal for the CO source. They are apparently negotiating with china to set up two plants there.

Also , from an article;
"A number of studies have attempted to estimate the global potential of biomass energy. Although the amount of sunlight reaching the earth's surface is substantial, less than a tenth of a percent of the total is actually captured and stored by plants. About half of it is reflected back to space. The rest serves to maintain global temperatures at life-sustaining levels.  ... "

To get the CO2 as you suggested, I suppose one would use heat exchangers; Cool the air to remove the water, then further cool to precipitate the CO2, then use the waste cooled air to pre-cool the incoming air. The CO2 ice is compressed into gas, into tanks.

If an 'air' to fuel process could run off a solar array, it would be quite neat to collect your free litre of fuel everday. The real difficult part is to quantify 'efficiency' See, even if you saved 50% of your current fuel costs, you'd probably spend that money on a holiday, or a new ICD3?, so where's the real saving in natural resources?

I think self-sufficiency and fun is the best motive for these endevours.


Regards
Roland Jollivet

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