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reducing coal pollution

Discussion in 'Environmental Discussion' started by austingreen, Aug 25, 2012.

  1. austingreen

    austingreen Senior Member

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    This year the price of natural gas dropped enough for the price of fuel in ccgt plants to be lower than the price in coal plants. A number of lawsuits along with the epa enforcing stricter rules will close down 8% of the most polluting coal

    27 gigawatts of coal-fired capacity to retire over next five years - Today in Energy - U.S. Energy Information Administration (EIA)[​IMG]

    This is much faster than the cap and trade plan would have legislated. But prices of natural gas and coal can reverse - they are about equal for ccgt and coal steam power plants now, and some simple legislation would help do this in an orderly way.

    Coal plant retirements - SourceWatch
    This shows more than half the capacity of coal was built before 1975, much of it grandfathered into law. A simple removal of the grandfathering could massively shut down old polluting power plants. It could also get rid of the expensive lawsuits and get things back on track. Something like

    In 2020 any coal plant older than 40 years old not meeting NOx, SO2, or particulate levels set by the EPA needs to shut down. The 7 years will give companies plenty of time to build new power plants. Even if half were replaced by new coal which is unlikely at today's prices, it would drastically reduce the amount of coal pollution.
     
  2. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Actually I've been remembering the old manufactured gas days and wondering if the thermodynamics would support coal conversion into a similar gas for power generation. In particular:
    • steam + partial-pyrolysis -> H{2} + CO + CH{4} + hydrocarbons + CO{2} + N{2}
    I suspect the coal processing plant would be nearly as capital intensive as the power plant. However, I also suspect the hydrocarbons might include distillable, liquid fuels.

    Granted, there won't be a great reduction in total CO{2} and I doubt that at the plant, sequestration is practical. However, I'm looking at as a source of former pollutants becoming new chemical feedstocks.

    What I don't know are the thermodynamics, the relative use the original calories to generate turbine steam.

    Bob Wilson
     
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  3. austingreen

    austingreen Senior Member

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    That is the idea behind IGCC. Molten cabonate fuel cells might be able to do conversions directly in the fuel cells since they are hot enough, but more research is needed.


    The thermodynamics are quite good as you can burn the coal gasses in turbines then use the waste heat to turn steam turbines. IGCC plants can be 45% efficient, the problem is capital costs. They cost much more than gas ccgt plants, and at today's prices the coal is only a little less expensive than the natural gas. Unhealthy pollutants are much lower than the coal plants we are closing, but there are some water pollution issues that are being worked out. The german's will be building large numbers of these power plants, as there natural gas prices/supply is different than the US.

    This project recaptures the CO2 for use in the oil fields.
    Carbon Capture & Storage Reference Plant Design - The Texas Clean Energy Project | texascleanenergyproject.com
    It also makes sulfuric acid and fertilizer from SO2 and NOx. The power plant should be running in 2014, but DOE money was used to make the payback seem worth while.

    Closing those 50+ year old coal power plants that spew so much unhealthy polutants would make igcc costs look much better.
     
  4. tochatihu

    tochatihu Senior Member

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  5. austingreen

    austingreen Senior Member

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    The medical costs are one reason to remove the grandfathering and shut the old plants down.

    I'm sure adding this cryogenic cooling will be too expensive to put on these old grandfathered plants. Newer plants already have scrubbers:) Then the question is really if cryogenic pollution control is affordable versus igcc. Since igcc is so much more efficient than powdered coal, I doubt it, but let them compete. igcc+ccs is estimated to cost $90-$130/MWh which is why we don't see it widespread. I'm very interested to see how much the new texas 400GW plant will end up costing. Wind costs about $80/MWh. This new method claims it will only add 25% energy costs or $56/0.75= $75/MWh, but until they build a plant I doubt it will come in that cheap.

    The real issue is do we want to allow these old plants to continue life. If we shut down all the pre-1975 coal in the next decade, and replace half of them with new coal, and the rest with renewables and natural gas ccgt, we should be able to drop the unhealthy emissions to less than half of what they are now. Ghg would drop by about 25%. There must be a majority of americans, that even if they don't believe in ghg problems, want to shut down over 40 year old unhealthy coal plants.