Slashdot Mirror
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?"
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.
How we know is more important than what we know.
On of the big questions you have to ask yourself is, "What problem am I trying to solve?"
The real problems facing fuel cells-the reasons why fuel cells aren't widely used-are the cost of producing them, and the difficulties in creating fuel. You're not trying to address either of those issues. In addition, you advocate replacing hydrogen fuel cells by fuel cells based on different chemisty. Making hydrogen fuel cells cheaply is hard. Now you're adding in a different, potentially brand new chemistry - you can't just throw any old fuel into a fuel cell and expect it to work, the entire design would potentially need to be reworked, which means that your fuel cells are even more expensive.
The other question is "Why bother?" Whatever non-CO2 carbon byproduct you make, it'll yield much less energy than if you completed conversion to CO2. For what gain? High CO2 emissions aren't hurting current energy generation techniques. Due to efficiency over internal combustion, just converting to regular fuel cell will reduce the CO2 emissions at the end use point anyway.
You also ignore the regeneration of the waste. What chemistry would you use? Where would you get the energy from? If from fossil fuels, you'll still be generating CO2 - probably more than what would be generated by burning the fossil fuels directly, due to the second law of thermodynamics. If from biomass, the CO2 question is moot - the CO2 you release today is going to be reincorporated into plants tommorrow (and thus into your fuel in a week). Zero net CO2, and you don't even have to collect any waste. If the energy is from solar/wind/hydro/nuclear, you can generate H2 directly without CO2 discharge, or can create hydrocarbons/alcohol from CO2 and H2O (so you'll get no net gain in CO2 upon complete combustion).
In short, the problem you're trying to solve is not currently limiting anyone in any fashion, and even if CO2 emiting fuel cells were in popular use, your proposed techniques likely would be either superfluous or distinctly counter-productive.