[ExI] Coal Gasification and CO2 (was Re: Whatever happened to peak oil by 2020?)

[spike]

From: extropy-chat-bounces at lists.extropy.org
[mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of Kelly Anderson
Sent: Saturday, May 11, 2013 4:56 PM
To: ExI chat list
Subject: Re: [ExI] Coal Gasification and CO2 (was Re: Whatever happened to
peak oil by 2020?)

 

Ja, what I meant was use wind and ground based solar as an energy input to
convert coal to Diesel and octane.  The plant you cite burns coal to make
the power to convert coal to liquids.  This is a huge waste of coal.  When
you have solar and wind power available, use that power to drive the coal
conversion.

 

>.I'm not a great chemist, and the chemical composition of coal is very
complex, but my understanding of it is that to convert the carbon chains in
the coal to octane, you have to release carbon dioxide. This isn't from the
burning of the coal itself, but as a side effect of the conversion. I could
be wrong, but no matter the energy source, using the Fischer-Tropsch process
or similar, you would always release large amounts of CO2. I would love to
be wrong about this. Any chemistry gurus out there? -Kelly

 

 

Kelly, the easy way to do this kind of analysis is to look at the energy
content of 96 grams of carbon (from coal) vs 116 grams of octane, which is
how much octane could theoretically be synthesized with the 96 grams of
carbon.  Then you must make up the energy difference by some means, and you
need to supply the hydrogen by splitting water molecules.  

 

Thought experiment: imagine you have an unlimited supply of cheap electrical
power that you can't really use, and a pile of coal, and that you need to
make octane from the coal.  The answer is to use the Fischer Tropsch
process.  The South African plant burns coal to make the power the
traditional way with a coal fired Rankine cycle, then uses the power to
convert coal to liquid fuels.  This uses a lot of coal to make just a little
Diesel and octane.  If you had a lot of wind and solar power, and you were
using the FT process primarily as a load leveler and as a means of energy
storage, you get something like the thought experiment I proposed: when you
are making more energy than you can use or ship elsewhere, that energy
becomes practically free.  

 

I have seen the Columbia Gorge when the wind was howling, the wind turbines
practically spinning off their axles, the transmission cables smoking, and
just no way to use all the excess power.  If we take some of the energy now,
when it is plentiful and cheap, use it to build ground based (and possibly
space based) solar, nukes, and plenty of wind turbines, then we will have
enough later as oil gradually diminishes to convert natural gas from
fracking, coal and biomass into liquid fuels.

 

What this does is makes the FT process a means of load leveling rather than
an energy source.  The problem with a lot of the renewables is in load
leveling, since the sun doesn't always shine and the wind doesn't always
blow.  If we use it while the wind is howling to make Diesel, then we have
the option to crank up Diesel generators quickly when it is needed.

 

If we use wind and GB solar to convert coal to Diesel, the factory will have
inputs of water, coal and electric energy, and have outputs of octane and
oxygen.

 

spike

 

 

 

 

 

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