6 ms·
This sort of research always runs stuck on the concentration of CO2 required to operate it effenciently. Even the climate-change tripled CO2 content of the atmo
by candiodari 5y ago
This sort of research always runs stuck on the concentration of CO2 required to operate it effenciently. Even the climate-change tripled CO2 content of the atmosphere is only 0.04 percent. If you can get even 0.5% CO2 gas it is possible to hit 10% efficiency with very old processes, but that's just not possible to do without a lot of energy. Efficiently isolating it either takes months or uses way too much energy.
Now of course in warfare conditions "way too much energy" may not such a big problem. Price may also not be much of a problem. Militaries have done it in the past.
- p_l 5y agoUS Navy AFAIK considers using nuclear power on carriers to ignore the high energy requirements, and it's a net win for them as it reduces UNREP needs for aviation fuel.
- jagger27 5y agoThe two reactors of a Gerald R. Ford super carrier can output more than a gigawatt of power together. Seems like plenty to me.
- spockz 5y agoWhat is the effect on the nu nuclear fuel and in the maintenance windows? I don’t know enough about nuclear power plants. But it seems to me they degrade faster under full load. Or is this not the case?
- jagger27 5y agoYes, I think the fuel would be spent faster. No clue about maintenance windows (I am a layperson on this topic).
- kfprt 5y agoThe correct price comparison is the cost of getting fuel to some remote FOB in Afghanistan which is extremely high.
- wffurr 5y agoHow do you generate enough electricity at said remote FOB to create a useful amount of fuel? Forward-deployed nuclear reactors would do the job, but would also be enormously expensive and vulnerable.
- kfprt 5y agoSolar? It doesn't matter really since the technology is too far out.
- pwg 5y ago> How do you generate enough electricity at said remote FOB to create a useful amount of fuel? You might not need to go that far to make the overall system economical. Imagine an aircraft carrier retrofitted with this system to generate jet fuel for its planes. If it can synthesize more fuel that its complement of aircraft require (this is likely), then it can be a supply generator for the remote FOB. There's still logistics in shipping from that carrier at sea nearby into the remote FOB, but that becomes a shorter supply line than shipping the equivalent quantity of jet fuel from a refinery in the state of Louisiana to the same FOB.
- bpodgursky 5y agoJets don't launch from remote FOBs. (I hear you re: gas and diesel for land vehicles, but that's not the q)
- photochemsyn 5y agoI think with membrane separation you can get staged concentration, like they do with say, isotopic separation of heavy water (H2O vs D2O). With a 10-fold increase at each stage (400ppm -> 4000ppm -> 40,000ppm -> -> pure CO2) you end up with a pure CO2 stream (which is typically what you want for efficient high-pressure, high-temperature industrial chemistry). The real question is what kind of scale is needed to generate fuel at the levels desired - powering the concentrators, the water electrolyzers, the actual process (high pressure high temperature F-T synthesis). Ten square kilometers of solar panels and wind turbines for one oil tanker's worth per month? Of course, if the world had exhausted its fossil fuel reserves by say 1970 we'd already be doing this at scale.
- hagbard_c 5y agoStick one of those factories on the tailpipe of a coal-fired powerplant to raise the incoming CO2-concentration for a double win: you get to use coal (and, hence, gain votes in coal states) while producing JP6 (or something similar) without adding any CO2 to the environment.
- pjc50 5y agoYou can just Fisher-Troph coal directly to aviation fuel. Nazi Germany was forced to do this and the Allies kept bombing the plants. https://en.wikipedia.org/wiki/Leuna_works https://en.wikipedia.org/wiki/Leuna_works "A total of 6,552 (!!) bomber sorties over 20 US Eighth Air Force and 2 RAF attacks dropped 18,328 tons (!!) of bombs on Leuna ... Leuna bombing from May 12, 1944 to April 5, 1945 cost the Eighth Air Force 1,280 airmen (!!)"
- hagbard_c 5y agoSure you can, but that means you're using additional coal just for the purpose of making jet fuel, adding additional CO2 to the balance. By using CO2 from existing coal power plants you'll be CO2-neutral for the jet fuel. After all, if the point is to get fossil jet fuel it is even easier to use crude oil, of which there is plenty to go around. The Germans used the FT-process to get around the fact that they had coal of different types but only little oil, not because it is the easiest way to produce liquid hydrocarbons.