Sunday, December 14, 2008

"hydrogen-basic-energy-carrier"




We can divide "hydrogen-basic-energy-carrier" solution into 3 stages:
Production of hydrogen.
Storage and transport.
Conversion to other forms of energies as electricity, heat...
Hydrogen production methods:please see one of the best source: Renewable energy sources (PDF): aes.pdf - eBook: Alternative Energy Sources by Jakub Pusz Note that the hydrogen production methods are only update (pictures, additional info. and links) of Jakub Pusz's text.
The Bosh method
This method is based on decomposition of water vapour using coke in the temperature of 1200 degC to hydrous gas (CO+H2) and then converse the mixture of this gas with water vapour on Fe2O3 and Cr2O3 catalyst in the temperature of 300-450 deg C. Emitted CO2 is absorbed by water under increased pressure (10-30 Mpa) and NaOH absorbs residues.
C + H2O - > CO + H2 C + H2 + H2O -> CO2 + 2H2 The biggest disadvantage of this method is the necessity of achieving so high temperature what causes an immense loss of the energy.
Natural gas steam reforming - SMR
This method is composed of two steps. The first step is to expose natural gas to high-temperature steam to separate hydrogen from carbon atoms in natural gas (CH4), additionally carbon monoxide (CO) and carbon dioxide (CO2) are produced. The second step is to convert the carbon monoxide with steam to produce supplementary hydrogen and carbon dioxide.
CH4 + H2O -> CO + 3H2 CO + H2O -> CO2 + H2
Hydrogen produced by this method is not used as a fuel but in manufacture of fertilisers and chemicals and to upgrade the quality of petroleum products. Nowadays this is the most effective way of gaining hydrogen but it uses fossil fuels both in manufacturing process and as the heat source, what is a great disadvantage of this method.
Ad.
3H2 + CO named as "syngas" It's used ceramic membrane Sr-Fe-Co-O @ 900C to select gases CO, H2.CO + H2O -> H2 + CO2 (water gas shift reactor WGSR)

No comments:

Post a Comment