Catalytic Carbon Extraction in Fuel Cell Production?

garyebickford asks: "I've been following the discussions in the media regarding fuel cells & hydrogen fuel. I have an idea (really a set of ideas) for handling the CO2 issues, which could make fuel cells a better solution. Perhaps someone who know about such things can tell me whether it's workable or not. Speculating wildly, if the carbon could be retained in the process (in a discharge tank, for instance), then it might even be useful as a feedstock for plastics, for example. How might a fuel cell process (both production and use), possibly multistage or incorporating a catalytic pre-process, emit carbon in non-gaseous form? What about a fuel cell that just converted ethanol or higher weight hydrocarbons to methanol, or perhaps a nitrite or another byproduct? Consumers could then recycle this waste to the fuel station at the next fill-up. Even this incomplete process can provide more energy per weight or volume than hydrogen, in theory. Would such a process be possible, or feasible?" "Many fuels can be used in fuel cells, including hydrogen, methane/methanol, ethanol, and ammonia. One of the problems with all these, in fact any system that consumes hydrocarbons (either biomass or petroleum), is that at some point in the process the carbon is released as carbon dioxide. For H2 and NH3 the problem is in the production facility; for hydrocarbon fuels the fuel cell itself emits carbon in some form. Perhaps fuel cell research has tended to think in terms replacing the existing combustion model, with the given that output will be H2O and CO2. Is anyone studying the possibility of fuel cells that have other output chemistry?"

Comments

My solution

[dex22]

Build the fuel cell into a laser printer, and have it dump the carbon dust right into the toner cartridge. :)

Do it so I can plug my computer and display into it, and power them too, and I'll buy two.

What is it with laymen?

[QuantumG]

I have a layman understanding of physics. This means I can read about advances in the field of physics and sometimes understand what is going on. This does not mean that I can propose new ways of looking at things in the field of physics. Why? Because every physicist has a layman's understanding of physics. Anything that you can come up with, they've already thought of it.

Thankfully this doesn't happen in computer science very often. It does happen though. I remember having a long conversation with a guy who thought he had a great idea for a replacement for floppy disks (this was pre-USB). His idea was that the monitor could read the data from a device people carry around. At first I thought I misheard him. Then I calmly explained to him that monitors are output devices, not input devices. Then he asked what the difference was. Eventually he turned red and asked how you could do it. We had a discussion about flash memory and interface standards and then he got bored and went away.

Which is typically the flow of these conversations, so excuse me for not entertaining your brilliant idea.

Re:What is it with laymen?

[Spazmania]

I have a layman's understanding of architecture. That means I can't really create a correct blueprint. It doesn't preclude me coming up with a clever floorplan and asking an architect to turn it in to a usable blueprint.

Doesn't Work - Follow The Energy

[billstewart]

Different molecules have different energy levels in them - you extract energy by combining or splitting them. Different reactions also require a certain amount of energy to make them happen - you can have a reaction that will produce net energy but needs a certain temperature or amount of energy to get it started, and what catalysts do is provide alternate paths for the reaction to happen with less starting energy or lower starting temperatures.

Combining Carbon with Oxygen or Hydrogen with Oxygen produces energy - but splitting up a chain of carbon and hydrogen to get the individual atoms to do that with requires some energy, though it's a lot less than burning the C and H will provide. Catalytic Converters on cars take the unburned hydrocarbons in the exhaust, split them and burn them before they get out the exhaust pipes, and take partially burned carbon monoxide and finish burning it. It's a waste of energy, but it was going to be wasted anyway - the reason to do this is that hydrocarbons and CO lead to air-pollution problems including smog. (They also split various nitrogen oxides to give nitrogen and oxygen; I don't know if this is exothermic or if it's using heat generated by the other reactions.)

You can't split the CO2 up into C and O2 without putting back the energy you got out of that reaction, so a catalytic converter won't help you. You could do things like combine it with calcium oxide to make calcium carbonate, and store that, but the usual way to make calcium oxide is by heating calcium carbonate to get rid of the CO2, so that's really no help.

Re:Why?

[CreateWindowEx]

Also, why bother to do it the hard way when you can just take something like ethanol made from switchgrass, where all the carbon came from the air originally, and then just burn it in a regular engine less than $100 of modification. If you include the additional carbon that is sequestered into the ground by the root systems of the switchgrass (harvesting is basically just mowing off the top), it actually ends up as a net loss of carbon to the atmosphere (or at least enough to compensate for using a 15% addition of petroleum for E85). Yes, ethanol in the US is made inefficiently from corn right now, but converting to a more efficient system is a political problem, not a technological one, and not an insurmountable one. See Khosla's video for more info.