Submitted on April 8th, 2009 by gwashtracker (not verified)
Response to Unknown User:
What are you talking about? The chemistry is very clear - when the Calera patent refers to(Ca,Mg)O it is a clear reference to calcium/magnesium oxide (eg. calcined Dolomite) - cemistry dictates the use of the reactive oxides (or hydroxides) for carbonation reactionas at room temp. Whether Calera makes the oxide or buys it from a vendor is immaterial - its production has a large CO2 footprint - from the chemical release of CO2 from the carbonate and from the energy input for calcination.
Yes - the calcination of CaCO3 to CaO results in the net release of about 1.4 - 1.5 mol of CO2 per mol of CaO produced. Of course, you can re-react the CaO with CO2 - you would re-capture 1.0 mol of CO2 (at 100% carbonation efficiency), incur an energy expenditure equivalent to 0.1-0.15 mol of CO2 per mole of CaO for performing the pressurized carbonation - so the net process would have a positive carbon footprint of about 0.5 mol of CO2 per mole of CaO/CaCO3. There is a large net production of CO2. This is no surprise. So - what is your point???
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Response to Unknown
Submitted on April 8th, 2009 by gwashtracker (not verified)Response to Unknown User:
What are you talking about? The chemistry is very clear - when the Calera patent refers to(Ca,Mg)O it is a clear reference to calcium/magnesium oxide (eg. calcined Dolomite) - cemistry dictates the use of the reactive oxides (or hydroxides) for carbonation reactionas at room temp. Whether Calera makes the oxide or buys it from a vendor is immaterial - its production has a large CO2 footprint - from the chemical release of CO2 from the carbonate and from the energy input for calcination.
Yes - the calcination of CaCO3 to CaO results in the net release of about 1.4 - 1.5 mol of CO2 per mol of CaO produced. Of course, you can re-react the CaO with CO2 - you would re-capture 1.0 mol of CO2 (at 100% carbonation efficiency), incur an energy expenditure equivalent to 0.1-0.15 mol of CO2 per mole of CaO for performing the pressurized carbonation - so the net process would have a positive carbon footprint of about 0.5 mol of CO2 per mole of CaO/CaCO3. There is a large net production of CO2. This is no surprise. So - what is your point???