From: Spudboy100@aol.com
Date: Fri May 02 2003 - 21:33:27 MDT
<A HREF="http://www.cmt.anl.gov/science-technology/lowtempthermochemical.shtml">http://www.cmt.anl.gov/science-technology/lowtempthermochemical.shtml>
From Argonne National Labs
<<Hydrogen can be extracted from water using energy by electrolysis,
Themochemical cycle water-splitting processes offer the potential for making
The two most highly developed thermochemical cycles are the sulfur-iodine and
We have identified and are currently developing a copper-chlorine
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: Fri May 02 2003 - 21:44:49 MDT
thermolysis, and thermochemical cycles. The efficiency of electrolysis
(electricity needed to produce hydrogen) is typically about 75-80%; however
the electric power generation (thermal energy to electrical) is typically
30-35%. Hence, the conversion of water to hydrogen via commercial
electrolysis has an overall efficiency of only 20-25%. Thermolysis, a process
in which water is heated sufficiently to dissociate it into hydrogen and
oxygen, requires very high temperatures.
hydrogen at lower temperatures than thermolysis. Without the intermediate
production of electricity, overall efficiencies of 40-50% are expected. A
thermochemical process is a sequence of thermally driven chemical reactions
in which water and heat are the inputs, and hydrogen and oxygen are the
outputs. The other chemicals and reagents are recycled in a closed cycle.
the calcium-bromine cycles. Both contain at least one reaction that requires
temperatures greater than 750ºC. Process heat in that range (750-850ºC) could
be provided by next-generation nuclear power plants...
thermochemical process that yields hydrogen at a temperature of 500ºC.
* Advantages of Copper-Chlorine Thermochemical Cycle*
-Heat at required temperature could be supplied from existing power plant
technologies.
-Materials-of-construction and corrosion issues are more tractable at 500 oC
than at
higher temperatures.
-The cycle uses inexpensive raw materials.
-The energy efficiency of the process is projected to be 40-45%. >>