IN PREVIOUS articles, we listed down the practical ways, to cut down on anthropomorphic CO2 emission (by weaning ourselves off fossil fuels).
Practical and feasible ways for an archipelagic (islands) tropical country (rain everywhere) with lots of tectonic activity in the Pacific rim of fire (volcanoes, hot springs):
Geothermal power plants. (There should be ongoing projects in Negros at the very least for this.)
Hydroelectric power plants.
Modular relatively cheap floating nuclear plants
The third way, if implemented, would certainly go a long way to completely solving our energy problems. For an archipelagic country, this is an obvious recommendation as these can be towed anywhere there is shoreline. The only country that produces these is Russia. The Philippines should be ordering for these, but the present sanctions against Russia would preclude this option as of now.
Now back to the cutting down anthropomorphic CO2 emission. Another relatively minor way is related to the fact that the structural metals that the entire world use are chemically reduced from metal oxides in smelters. (The process of smelting also consumes lots of energy, most of which ultimately comes from fossil fuels, in which case the above three recommendations to cut down on fossil fuel consumption holds.)
The basic reaction is Metal oxide + Carbon = Metal + Carbon dioxide
Almost all of the billions of tons of structural metal that humanity produces each month is iron (aluminum being a far distant second.)
Thus, the above process can be simplified as: Iron oxide (hematite Fe2O3 or magnetite Fe3O4) + carbon (C) → elemental iron (Fe) + carbon dioxide (CO2)
Most of the elemental iron goes into steelmaking. Various sources estimate steelmaking as responsible for about 10% (or more) of CO2 emission by humanity. Making a ton of steel emits nearly two tons of CO2.
In most of the world, the carbon that iron smelters consume comes from coal. Coal usage outputs a huge amount of net CO2 into the atmosphere. But there is a way to avoid using coal as the reducing agent for iron oxides. Use charcoal instead.
It’s actually being done. Brazil is one of the world’s leading iron producer. But it lacks significant coal deposits. Thus, the Brazilians use charcoal instead, from millions of commercially grown eucalyptus trees planted and harvested serially every few years in millions of hectares of plantations. It must be noted that these are planted around the natural Amazon forest of Brazil. The forest is left untouched. This also protects the forest from illegal loggers because buyers of lumber can simply buy legal commercial eucalyptus products.
Using charcoal for fuel or as reducing agents for metal oxides is carbon-neutral, meaning it does not result in a net CO2 emission into the atmosphere. Why?
Because the carbon from charcoal comes from the CO2 that plants fixed in photosynthesis, taken directly from the air just within a short period of time (at most several decades).
Below is a simplified and short summery of the chemical processes involved:
* Equation for photosynthesis: 6 CO2 (taken from the atmosphere) + 6 H2O → C6H12O6 (organic substance) + 6 O2
* Equation for charring/ carbonization (charcoal production): C6H12O6 (organic substance) → 6 H2O (water) + 6 C (charcoal carbon)
* Equation for the reduction of iron oxides in smelters: FeO2 (iron oxide) + C (charcoal carbon) → Fe (elemental iron) + CO2
If we are actually strict about it, the final result is elemental iron and a net emission of oxygen into the atmosphere. The oxygen comes from the iron oxide. Elemental carbon in effect steals the iron oxide’s oxygen to form CO2. However, in the previous photosynthetic and charring process, atmospheric CO2 was reduced to the above elemental carbon with the net emission of O2. The final summary of the reducing process would be: Iron oxide (FeO2 or Fe2O3 or Fe3O4) → elemental iron Fe + O2
{But no one would certainly complain about extra oxygen getting into the atmosphere.}
In summary, the carbon in charcoal is taken from the atmosphere, and so burning it or using it as a reducing agent in smelters just returns the CO2 that plants fixed in photosynthesis back into the atmosphere. Other words, charcoal usage is carbon-neural, meaning it does not result in a net CO2 emission into the atmosphere.
It must be noted that the main and probably the only significant reason why the Brazilians are using charcoal in their iron smelters is economic necessity. They just lack cheap coal deposits. However, if there comes a time when the usage of coal decreases (ether because deposits are running out or because of legislation), then charcoal can be feasibly used in the iron industry./PN
