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Thread: Carbon capture plan is shelved

  1. #1 Carbon capture plan is shelved 
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    Utility Shelves Ambitious Plan to Limit Carbon

    "WASHINGTON — A major American utility is shelving the nation’s most prominent effort to capture carbon dioxide from an existing coal-burning power plant, dealing a severe blow to efforts to rein in emissions responsible for global warming.
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    American Electric Power has decided to table plans to build a full-scale carbon-capture plant at Mountaineer, a 31-year-old coal-fired plant in West Virginia, where the company has successfully captured and buried carbon dioxide in a small pilot program for two years. "

    http://www.nytimes.com/2011/07/14/bu..._r=1&ref=earth

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    As an investor of other utilities this makes perfect sense. Congress could have probably fixed this by encouraging the DOE to allow similar pricing options already available to other utilities who are investing in renewable with money that volunteer consumers agree to pay as a small surcharge.


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  3. #2  
    Forum Isotope Bunbury's Avatar
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    That's unfortunate. I'm not familiar with this project but I'll guess the problem is the same one that bedevils most carbon capture projects, which is that the CO2 is produced at essentially atmospheric pressure and has to be cooled, absorbed in a solvent (amines usually) then reheated, then compressed and then cooled again to a pressure and temperature suitable for deep underground injection. All the cooling and heating and compression uses up a lot of energy and makes the whole process expensive to operate.

    There is development work proceeding on combusting coal at high pressures using metal oxides as the oxygen carrier so that the waste stream is a high pressure stream of almost pure CO2. This is many years away from large scale commercialization and in any case won't affect existing coal burning plant.


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    Forum Professor Wild Cobra's Avatar
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    Quote Originally Posted by Bunbury View Post
    That's unfortunate. I'm not familiar with this project but I'll guess the problem is the same one that bedevils most carbon capture projects, which is that the CO2 is produced at essentially atmospheric pressure and has to be cooled, absorbed in a solvent (amines usually) then reheated, then compressed and then cooled again to a pressure and temperature suitable for deep underground injection. All the cooling and heating and compression uses up a lot of energy and makes the whole process expensive to operate.

    There is development work proceeding on combusting coal at high pressures using metal oxides as the oxygen carrier so that the waste stream is a high pressure stream of almost pure CO2. This is many years away from large scale commercialization and in any case won't affect existing coal burning plant.
    Yes, the costs are just too high. I calculated the initial cost they had as taking more than 16 years to pay off at 2 cents/kwh. That didn't include any upkeep costs. As for the new system that you speak of. It's still high pressure and still needs cooling. Do you know if the design is geared for carbon capture, or just greater efficiency for coal power generation, and/or less particulate output?
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    Forum Isotope Bunbury's Avatar
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    Quote Originally Posted by Wild Cobra View Post
    [As for the new system that you speak of. It's still high pressure and still needs cooling. Do you know if the design is geared for carbon capture, or just greater efficiency for coal power generation, and/or less particulate output?
    You can google it - it's called a chemical looping reactor.

    The difference regarding pressure is that you are handling much smaller volumes of gases that require compressing. The coal reacts directly with metal oxides producing pure CO2 and reduced metal which are easily separated by centrifuging. The pure CO2 stream still has to be compressed and cooled to inject it, but you do not have to separate it from nitrogen and excess oxygen. The reduced metal is re-oxidized with air but again the metal oxides are separated from the excess air by centrifuging. The metal and the oxides are circulated continuously - hence the looping reactor. The coal/metal oxide reaction is exothermic and I understand the re-oxidation of the metal is also exothermic in most cases so an optimized system can generate much energy for steam production to turn turbines.

    There is a lot of research proceeding and I anticipate big challenges in scale-up to commercial size. But it is promising.
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    Forum Professor Wild Cobra's Avatar
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    Quote Originally Posted by Bunbury View Post
    Quote Originally Posted by Wild Cobra View Post
    [As for the new system that you speak of. It's still high pressure and still needs cooling. Do you know if the design is geared for carbon capture, or just greater efficiency for coal power generation, and/or less particulate output?
    You can google it - it's called a chemical looping reactor.

    The difference regarding pressure is that you are handling much smaller volumes of gases that require compressing. The coal reacts directly with metal oxides producing pure CO2 and reduced metal which are easily separated by centrifuging. The pure CO2 stream still has to be compressed and cooled to inject it, but you do not have to separate it from nitrogen and excess oxygen. The reduced metal is re-oxidized with air but again the metal oxides are separated from the excess air by centrifuging. The metal and the oxides are circulated continuously - hence the looping reactor. The coal/metal oxide reaction is exothermic and I understand the re-oxidation of the metal is also exothermic in most cases so an optimized system can generate much energy for steam production to turn turbines.

    There is a lot of research proceeding and I anticipate big challenges in scale-up to commercial size. But it is promising.
    LOL...

    Sounds pretty cool....

    I think you're right. I like the idea of removing the NOx also.
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