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I'm trying to figure out how to sequester CO2 from furnace exhaust

  1. Jan 3, 2012 #1
    My plan is to burn bio-matter like weeds and wood (or bio-fuel) in a zero-pollution scheme that collects the particulate material, oil, water and CO2 generated from burning the hydrocarbons and uses it for other purposes. It would filter out any toxins or NOx and vent N2.

    I know that I can cool the exhaust and run the air through filters to remove particles and also force it through a hydroxide solution to form carbonate or bicarbonate.

    My sense is that I can remove most of the CO2 from the exhaust but I am not sure how to easily harvest the CO2 from my "waste" carbonate. I figure that NaOH is the easiest to get a hold of so I would like the info about that rather than Ca.

    I understand that either heating the carbonate or electrolizing it will yield the CO2(g)? Ultimately, it is the Co2(g) what I am trying to harvest. I want the CO2 for my green house and refrigeration.

    I am also need to know the composition of smoke and exhaust. I understand that there is soot, steam, N2 and CO2 and maybe some O2 and NOx, sulfer, etc...

    I am not sure what the soot is. I have ideas about using the ash and carbon waste (if that's what it is).

    1. What is the ash and resin that I am collecting in the filters comprised of if I burn weeds or wood?

    2. Is there an easy way to make carbon fiber and could the ash waste be used for that purpose?

    3. What is the composition of the smoke from burning plants like weeds and wood?

    4. What is the best way to filter burned-plant exhaust to a) eliminate pollution, b) harvest the CO2, and c) harvest carbon waste (resin or ash)?

    5. If I use NaOH to absorb the CO2, will I produce Na2CO3 or NaHCO3 and what is the best way to get back the CO2(g)?

    6. What will I get from electrolizing carbonate or bicarbonate? (I know that is broad, but please elaborate)

  2. jcsd
  3. Jan 6, 2012 #2


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    Staff: Mentor

    Burning wood produces tar which condenses out in the chimney. I expect the tar contains carcinogens. Even when you fan the fire to ensure all carbon is oxidized, fine ash remains, and its composition includes minerals that were in the plant material, and dust and sand that was trapped in the bark.
  4. Jan 7, 2012 #3
    As far as impacting the environment, any CO2 you've released is simply CO2 that was captured by the plant during growth.

    In addition, you tend expend effort boiling off trapped water during combustion. Thus the old addage "Green wood don't burn." The solution to this is to season your plantstuff. Allowing it to spent a year out of the rain usually helps greatly.

    The smoke is mostly unburnt hydrocarbons and moisture. This represents a waste of energy and source of pollution. The answer is typically to have a catalyst bed that the waste stream passes through. There are a number of wood burning stoves that feature a catalyst honeycomb followed by a second chamber that acts as a heat exchanger to extract the heat.

    Finally, you have the ashes. Ashes are rich in minerals, but may also be rich in caustic compounds (such as NaOH). At one time, people would harvest the caustic chemicals, react them with fatty materials and produce soap. The caustic reagents from ashes was also used for the extraction of oxidizers from manure, thus supplying a key ingredient in gownpowder.

    I don't know what the modern solution to ashes would be. Possibly to simply spread them, let them react with CO2 to form carbonates, and utilize the remainsders in fertilizer.

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