4 ms·

As a former chemist involved in the field, no, we're really not. Reading the Joule letter referenced, it's basically just cheerleading, which does need to happ

As a former chemist involved in the field, no, we're really not. Reading the Joule letter referenced, it's basically just cheerleading, which does need to happen every few years to keep people going. Last I was involved, all the major non-nanosurface based catalysts either had horrible separability or cycles in the 1k range. Commercial catalysts frequently have cycles in the billions. When someone cracks this nut, they'll make money hand over fist, but we're not there yet. JACS has a review article every few years on this for anyone with high school chem and an actual interest.

lambdadmitry 9y ago
I tried to find such a review, but failed. Can you please provide a bit more pointers?
- ianai 9y ago
  I’m curious as well.
- drewbuschhorn 9y ago
  "Co2 fixation" / capture is the starting keyword you want, though "coalgas" frequently turns up good fundemental work from the 80s. https://pubs.acs.org/journal/jacsat#/action/doMobileSearch?&startPage=0&searchText=Co2%20fixation https://pubs.acs.org/journal/jacsat#/action/doMobileSearch?&... For reviews specifically: https://pubs.acs.org/journal/jacsat#/action/doMobileSearch?&SeriesKey=chreay&searchText="CO2%20fixation"&content=pubs https://pubs.acs.org/journal/jacsat#/action/doMobileSearch?&... See also Royal Society: http://pubs.rsc.org/en/content/articlelanding/2014/cs/c3cs60373c#!divAbstract http://pubs.rsc.org/en/content/articlelanding/2014/cs/c3cs60... . I can try and do a better filter job if people want, I think jacs keyword matching has managed to get worse.
neltnerb 9y ago
Not to mention that basically all the collected data and goals are centered on flue gas with high CO2 concentrations. It's contradictory, if you have isolated fossil power and for some reason have excess renewable power co-located to convert the waste back to chemicals, then just turn off the fossil power... unless this is a load balancing play, which it is not ever going to be good for. And the original oil and coal is better for converting to chemicals anyway!
- drewbuschhorn 9y ago
  Yep, saying your going to gassify crude oil and then recycle the co2 is basically like saying your going to unspill milk. The only point in the thing's favor is that there's tons floating around already.
- masonic 9y ago
  flue gas with high CO2 concentrations Wouldn't such a technology be useful in "scrubbing" exhaust from electrical plants, at least?
  - wffurr 9y ago
    The power requirements are such that you could just deliver that power to the grid in place of the fossil fuel generated power you are cleaning.
    - neltnerb 9y ago
      Exactly. The maximum efficiency of conversion to electricity in a thermal plant is maybe 30-40% even ignoring losses in converting back to hydrocarbons. But even 99% would be a loss relative to simply using the original hydrocarbons. This is a rube goldberg machine, taking high value hydrocarbons that could be converted to commodity and fine chemicals and instead burning them and taking the released carbon and... putting it back together? It's not even a very efficient perpetual motion machine.
08-15 9y ago
But why is anyone cheerleading for this pointless technology? Why bother with capturing a trace gas from the atmosphere? It seems to me that stranded clean energy would be better spent making ammonia. We've been making ammonia from air and natural gas for a hundred years, we know how to make it from air, water and electricity. It is easy to transport, the market for it is huge, and making ammonia "captures" CO2 by replacing a different plant that would have emitted it. If we really wanted to take CO2 back out of the atmosphere (and we don't need to even think about that as long as there a coal, oil and gas burning power plants everywhere), we should simply grind up silicate rocks. Doing so makes reasonably good soil that may not even need fertilizer (other than ammonia), and once plants grow in it, it with weather rather quickly, thereby permanently sequestering CO2. Seriously, why bother with CO2 capture from air? Looks like a fool's errand to me.
- drewbuschhorn 9y ago
  If you can beat the HB and Ostwald processes, I say go for it. I think the idea behind carbon capture from serious people is: 1. That it should be solar powered / low energy 2. Catalyst cheap as dirt, so that 3. CO2 in the air is free, so you'd basically have the plant start up costs and then the rest is free money. Also envy of the plants for making it look easy. Anybody saying it would make a dent on the global CO2 consumption is just spouting grant proposal talk, for the entropic reasons everyone else is talking about on this thread, or else is a crazy geoengineering nut. That being said, if you dig into it, most groups that publish papers on the subject do it as an interesting sideline / something to grab some low hanging attention. It's really just checked out as a side effect of other things, like being able to functionalize hard to move chemical groups. One of my Fe compounds could capture CO2 gas and convert it into oxalic acid ( H2O + 2CO2 =cat=> H2(CO2)2 + 1/2O2 ) ... almost a whole 50 cycles before it got poisoned by its own O2 production (the compound burst into flames in air, btw). But it could also functionalize one of the lowest energy N bonds known, and in a selective fashion. It was floated as a means for a two step synthesis of some kidney drug, but ... the bursting into flame thing.
  - philipkglass 9y ago
    If you can beat the HB and Ostwald processes, I say go for it. You wouldn't try to beat those processes. You'd run them as usual but with hydrogen from water electrolysis instead of from steam-reformed fossil resources. Of course both levelized cost of renewable electricity and cost of running electrolyzers at low duty cycle need to decline significantly more before that could compete with the current status quo of cheap natural gas and no CO2 emission taxes. Renewable ammonia made this way still seems more plausible for near-future commercialization than making liquid hydrocarbon fuels from renewable electricity and atmospheric CO2. Which is admittedly faint praise. The advantage that might eventually be significant is that it's easier to ship ammonia or simple derivatives of it from some remote but renewable-energy-resource-rich place, like windy islands, than to build electricity transmission lines.

lambdadmitry 9y ago

I tried to find such a review, but failed. Can you please provide a bit more pointers?

ianai 9y ago
I’m curious as well.
drewbuschhorn 9y ago
"Co2 fixation" / capture is the starting keyword you want, though "coalgas" frequently turns up good fundemental work from the 80s. https://pubs.acs.org/journal/jacsat#/action/doMobileSearch?&startPage=0&searchText=Co2%20fixation https://pubs.acs.org/journal/jacsat#/action/doMobileSearch?&... For reviews specifically: https://pubs.acs.org/journal/jacsat#/action/doMobileSearch?&SeriesKey=chreay&searchText="CO2%20fixation"&content=pubs https://pubs.acs.org/journal/jacsat#/action/doMobileSearch?&... See also Royal Society: http://pubs.rsc.org/en/content/articlelanding/2014/cs/c3cs60373c#!divAbstract http://pubs.rsc.org/en/content/articlelanding/2014/cs/c3cs60... . I can try and do a better filter job if people want, I think jacs keyword matching has managed to get worse.

neltnerb 9y ago

Not to mention that basically all the collected data and goals are centered on flue gas with high CO2 concentrations. It's contradictory, if you have isolated fossil power and for some reason have excess renewable power co-located to convert the waste back to chemicals, then just turn off the fossil power... unless this is a load balancing play, which it is not ever going to be good for. And the original oil and coal is better for converting to chemicals anyway!

drewbuschhorn 9y ago
Yep, saying your going to gassify crude oil and then recycle the co2 is basically like saying your going to unspill milk. The only point in the thing's favor is that there's tons floating around already.
masonic 9y ago
flue gas with high CO2 concentrations Wouldn't such a technology be useful in "scrubbing" exhaust from electrical plants, at least?
- wffurr 9y ago
  The power requirements are such that you could just deliver that power to the grid in place of the fossil fuel generated power you are cleaning.
  - neltnerb 9y ago
    Exactly. The maximum efficiency of conversion to electricity in a thermal plant is maybe 30-40% even ignoring losses in converting back to hydrocarbons. But even 99% would be a loss relative to simply using the original hydrocarbons. This is a rube goldberg machine, taking high value hydrocarbons that could be converted to commodity and fine chemicals and instead burning them and taking the released carbon and... putting it back together? It's not even a very efficient perpetual motion machine.

08-15 9y ago

But why is anyone cheerleading for this pointless technology? Why bother with capturing a trace gas from the atmosphere? It seems to me that stranded clean energy would be better spent making ammonia. We've been making ammonia from air and natural gas for a hundred years, we know how to make it from air, water and electricity. It is easy to transport, the market for it is huge, and making ammonia "captures" CO2 by replacing a different plant that would have emitted it. If we really wanted to take CO2 back out of the atmosphere (and we don't need to even think about that as long as there a coal, oil and gas burning power plants everywhere), we should simply grind up silicate rocks. Doing so makes reasonably good soil that may not even need fertilizer (other than ammonia), and once plants grow in it, it with weather rather quickly, thereby permanently sequestering CO2. Seriously, why bother with CO2 capture from air? Looks like a fool's errand to me.

drewbuschhorn 9y ago
If you can beat the HB and Ostwald processes, I say go for it. I think the idea behind carbon capture from serious people is: 1. That it should be solar powered / low energy 2. Catalyst cheap as dirt, so that 3. CO2 in the air is free, so you'd basically have the plant start up costs and then the rest is free money. Also envy of the plants for making it look easy. Anybody saying it would make a dent on the global CO2 consumption is just spouting grant proposal talk, for the entropic reasons everyone else is talking about on this thread, or else is a crazy geoengineering nut. That being said, if you dig into it, most groups that publish papers on the subject do it as an interesting sideline / something to grab some low hanging attention. It's really just checked out as a side effect of other things, like being able to functionalize hard to move chemical groups. One of my Fe compounds could capture CO2 gas and convert it into oxalic acid ( H2O + 2CO2 =cat=> H2(CO2)2 + 1/2O2 ) ... almost a whole 50 cycles before it got poisoned by its own O2 production (the compound burst into flames in air, btw). But it could also functionalize one of the lowest energy N bonds known, and in a selective fashion. It was floated as a means for a two step synthesis of some kidney drug, but ... the bursting into flame thing.
- philipkglass 9y ago
  If you can beat the HB and Ostwald processes, I say go for it. You wouldn't try to beat those processes. You'd run them as usual but with hydrogen from water electrolysis instead of from steam-reformed fossil resources. Of course both levelized cost of renewable electricity and cost of running electrolyzers at low duty cycle need to decline significantly more before that could compete with the current status quo of cheap natural gas and no CO2 emission taxes. Renewable ammonia made this way still seems more plausible for near-future commercialization than making liquid hydrocarbon fuels from renewable electricity and atmospheric CO2. Which is admittedly faint praise. The advantage that might eventually be significant is that it's easier to ship ammonia or simple derivatives of it from some remote but renewable-energy-resource-rich place, like windy islands, than to build electricity transmission lines.