3 ms·

Isn't "carbon from limestone" basically coal (and then poor quality coal)?

• dredmorbius 10y ago
  If your interest is chemistry, not energy, then what you're looking for is a large supply of carbon. Limestone offers that. I'm not particularly versed in what the chemistry would look like, but if the interest is in, say, providing carbon to coking processes (allowing a non-energy carbon source to be combined with, say, direct solar thermal or electrically-provided heat), which accounts for about 15% of all present coal usage, then you're onto something. I'm aware that limestone was considered for Fischer-Tropsch fuel synthesis based on nuclear-generated electricity, at Brookhaven National Labs in the 1960s (Meyer Steinberg, I believe, I've written on this and documented much of the literature at https://reddit.com/r/dredmorbius https://reddit.com/r/dredmorbius). For plastics, etc., the situation's largely similar. I suspect limestone, based on fossilised shellfish, is more abundant than coal, based on fossilised plant matter, given that conditions for limestone formation are probably easier to come by. For non-energy use, this might be a viable long-term option. And, yes, burning limestone-originated carbon, in the synfuel instance, would be similarly problematic as burning coal is in terms of increasing atmospheric and oceanic CO2 (and carbonate/bicarbonate) levels. I'm mentioning the research interest, not endorsing it. More recent research along those lines looks at carbon recovery from seawater, or possibly atmospheric carbon, though the latter is vastly more energy intensive.