From: Dickey, Michael F (michael_f_dickey@groton.pfizer.com)
Date: Fri Apr 12 2002 - 08:59:05 MDT
-----Original Message-----
From: Mike Lorrey [mailto:mlorrey@datamann.com]
Sent: Thursday, April 11, 2002 6:53 PM
To: extropians@extropy.com
Subject: CO2: Los Alamos perfects extraction process...
http://www.lanl.gov/worldview/news/releases/archive/02-028.shtml
LOS ALAMOS, N.M., April 9, 2002 -- Researchers at the U.S. Department of
Energy's Los Alamos National Laboratory are studying a simple, cost
effective method for extracting carbon dioxide directly from the air which
could allow sustained use of fossil fuels while avoiding potential global
climate change.
-----------------------------
The sabatier reaction seems to me to be a much better Idea. If you run CO2
and Hydrogen over a heated catalyst (such as ruthenium) out comes CH4
(methane) and Water vapor. The water vapor can be condensed and
electrolysed and the hydrogen recycled out of it, and run over the catalyst
with more CO2. The methane could then been used again as fuel, the whole
system is powered by either solar panel or a nuclear plant. Such a system
would effectively relegating fossil fuels to recyclable and effecient
batteries, which is what they should be used for. As you 'battery' is used
up, it goes into the air. 'Recharging' it constitutes taking the CO2 back
out and putting it in a burnable form again using an effecient (nuclear) or
renewable (solar) energy source. Problem solved.
Michael
Sabatier Process
The CO2 in the Martian Atmosphere will be used to produce methane by the
so-called Sabatier process (discovered by the French chemist Paul Sabatier
in the nineteenth century). The reaction converts carbon dioxide with
hydrogen at elevated temperatures into methane and water (Stephen J.
Hoffman, David I. Kaplan,1997):
4H2 + CO2 ---> CH4 + 2H2O
Since no hydrogen is found in the Martian atmosphere, the hydrogen has to be
imported from Earth or from the Moon and NEOs. CH4/O2 rocket propellant only
consists of 16% hydrogen by mass. Therefore, the reduction in mass that has
to be brought from Earth to Mars is still substantial. A quick calculation
shows that about 0.222 kg of H2 and 1.222 kg of CO2 are needed to produce 1
kg of water and 0.444 kg of CH4.
Methane and the oxygen can be used for several applications. The most
obvious is probably the use as propellants for spacecraft and rovers. The
feasibility and applicability of methane as rocket fuel can be assumed given
the fact that a Russian company (Makeyev) is currently developing a launcher
with liquid methane engines in order to decrease launch cost. The use of
methane as rover fuel on the other side could eliminate the need for RTG or
reactor powered rovers, and also avoids the limited range of battery powered
rovers. If cryogenic methane and oxygen are used, than the rover could be
propelled by a piston engine. Since no compression is required (the two
liquids just have to be brought together and ignited), the engine would be
very simple and robust. In a case of a complete failure of all life support
systems and/or loss of the power system, the rovers and their propellants
could be used as a survival cache for the crew. The crew will breathe the
oxygen, and together with methane it can be used to produce power (for
example in fuel cells). Apart from carbon dioxide, water would be a product
of this reaction, which again can be consumed or be used otherwise by the
crew in an open loop "survival" system. All these benefits can be achieved
without the necessity of bringing huge quantities of consumables from Earth
(Pauly, 1998).
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