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Could Biochar be used to sequester carbon from coal powerstations?
Rather than gassifiying coal and separating hydrogen and CO2 (after the other pollutants are removed), and then trying to inject that CO2 deep into the earths crust, would it not be a better approach to slow the pyrolysis process down and cut it short to produce char rather than CO2 gas? That way the carbon could be safely stored in the char and used for topsoil fertilization and sequestration, rather than the effort, risk and WASTE of letting the carbon turn to a very unwanted gas.
Or have I missed something fundamental and have this totally wrong?
Oh yeah LRG, I definately agree with you. The sulphur and mercury (and everything else) would need to be scrubbed out as well, to prodce (ahem...) clean coal. Well, clean char, with clean methane to either convert to hydrogen or simply burn for energy in a natural gas turbine.
And yep there would certainly be energy lost in the process. Around 50% is what I've been told.
But my overall point was/is, why is the current proposal for 'clean coal' based on making the carbon in coal into CO2 gas and injecting it deep underground where it's useless and potentially dangerous, instead of into a FAR more productive, safe, and guaranteed medium like biochar?
The other arguments still absolutely stand, and I'd prefer to see renewables in any case.
2 Answers
- Anonymous1 decade agoFavorite Answer
i sort of get what you mean but i think the energy penalty would be prohibitive. also, there are several nasties in coal, mercury and sulphur in particular, which might make the char unsuitable for agricultural use. its certainly not advised to use coal ash on the garden in the way we use wood ash.
- Anonymous1 decade ago
If you produce carbon back from CO2 it could be used again to feed the power-station and you would have a "motu perpetuo" what obviously is impossible.
The reality is that doing so the energetic balance of the power station would be negative.