Natural CO2 emissions versus human created

Discussion in 'Environment' started by Old Rocks, Dec 19, 2010.

  1. Old Rocks
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    Old Rocks Diamond Member

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    One can tell the depths of ignorance or dishonesty in a poster when they start the yap-yap about how miniscule man's CO2 emissions are compared to natures. Of course, they just happen to fail to mention that nature is absorbing more CO2 than it is emitting. At least for the present.

    http://www.skepticalscience.com/docs/Guide_to_Skepticism.pdf

    Humans are raising CO2 levels 2
    When you look through the many arguments from
    global warming ‘skeptics’, a pattern emerges. They
    tend to focus on small pieces of the puzzle while
    neglecting the bigger picture. A good example of this
    is the argument that human carbon dioxide (CO2 )
    emissions are tiny compared to natural emissions.
    The argument goes like this. Each year, we send over
    20 billion tonnes of CO2 into the atmosphere. Natural
    emissions come from plants breathing out CO2 and
    outgassing from the ocean. Natural emissions add
    up to 776 billion tonnes per year. Without a full
    understanding of the carbon cycle, our emissions
    seem tiny when compared to nature’s contribution.

    CO2 and huge amounts of
    CO2 dissolve into the
    ocean. Nature absorbs 788
    billion tonnes every year.
    Natural absorptions roughly
    balance natural emissions.
    What we do is upset the
    balance. While some of our
    CO2 is being absorbed by
    the ocean and land plants, around half of our CO2
    emissions remain in the air.

    Edited-CO2
     
  2. CrusaderFrank
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    CrusaderFrank Diamond Member

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    CO is carbon monoxide, right?

    Don't catalytic converters convert CO to CO2?
     
  3. Intense
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    Intense Senior Member

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    Why are you talking about Carbon Monoxide and Carbon Dioxide as if it is the same thing?????

    Please clarify?????
     
  4. Big Fitz
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    Big Fitz User Quit *****

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    I wonder how much CO a forest fire or volcano gives off? huh.
     
  5. Intense
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    Intense Senior Member

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    Hot fires burn pretty clean. Wet fires, slow burns, oxygen starved, will throw off CO.
     
  6. Big Fitz
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    True... but no burn is perfect. All emit some level of CO.
     
  7. Intense
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    Intense Senior Member

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    CO2
    As for other complete combustion processes, nearly all of the carbon content in the waste is emitted as CO2 to the atmosphere. MSW contains approximately the same mass fraction of carbon as CO2 itself (27%), so incineration of 1 ton of MSW produces approximately 1 ton of CO2.

    If the waste was landfilled, 1 ton of MSW would produce approximately 62 cubic metres (2,200 cu ft) methane via the anaerobic decomposition of the biodegradable part of the waste. This much methane has more than twice the global warming potential than the 1 ton of CO2, which would have been produced by incineration. In some countries, large amounts of landfill gas are collected, but still the global warming potential of the landfill gas emitted to atmosphere in the US in 1999 was approximately 32 % higher than the amount of CO2 that would have been emitted by incineration.[16]

    In addition, nearly all biodegradable waste has biological origin. This material has been formed by plants using atmospheric CO2 typically within the last growing season. If these plants are regrown the CO2 emitted from their combustion will be taken out from the atmosphere once more.

    Such considerations are the main reason why several countries administrate incineration of the biodegradable part of waste as renewable energy.[17] The rest – mainly plastics and other oil and gas derived products – is generally treated as non-renewables.

    Different results for the CO2 footprint of incineration can be reached with different assumptions. Local conditions (such as limited local district heating demand, no fossil fuel generated electricity to replace or high levels of aluminum in the waste stream) can decrease the CO2 benefits of incineration. The methodology and other assumptions may also influence the results significantly. For example the methane emissions from landfills occurring at a later date may be neglected or given less weight, or biodegradable waste may not be considered CO2 neutral. A study by Eunomia Research and Consulting in 2008 on potential waste treatment technologies in London demonstrated that by applying several of these (according to the authors) unusual assumptions the average existing incineration plants performed poorly for CO2 balance compared to the theoretical potential of other emerging waste treatment technologies.[18]

    [edit] Other emissions
    Other gaseous emissions in the flue gas from incinerator furnaces include sulfur dioxide, hydrochloric acid, heavy metals and fine particles.

    The steam content in the flue may produce visible fume from the stack, which can be perceived as a visual pollution. It may be avoided by decreasing the steam content by flue gas condensation and reheating, or by increasing the flue gas exit temperature well above its dew point. Flue gas condensation allows the latent heat of vaporization of the water to be recovered, subsequently increasing the thermal efficiency of the plant.

    [edit] Flue gas cleaning
    The quantity of pollutants in the flue gas from incineration plants is reduced by several processes.

    Particulate is collected by particle filtration, most often electrostatic precipitators (ESP) and/or baghouse filters. The latter are generally very efficient for collecting fine particles. In an investigation by the Ministry of the Environment of Denmark in 2006, the average particulate emissions per energy content of incinerated waste from 16 Danish incinerators were below 2.02 g/GJ (grams per energy content of the incinerated waste). Detailed measurements of fine particles with sizes below 2.5 micrometres (PM2.5) were performed on three of the incinerators: One incinerator equipped with an ESP for particle filtration emitted 5.3 g/GJ fine particles, while two incinerators equipped with baghouse filters emitted 0.002 and 0.013 g/GJ PM2.5. For ultra fine particles (PM1.0), the numbers were 4.889 g/GJ PM1.0 from the ESP plant, while emissions of 0.000 and 0.008 g/GJ PM1.0 were measured from the plants equipped with baghouse filters.[19][20]

    Acid gas scrubbers are used to remove hydrochloric acid, nitric acid, hydrofluoric acid, mercury, lead and other heavy metals. Basic scrubbers remove sulfur dioxide, forming gypsum by reaction with lime.[21]

    Waste water from scrubbers must subsequently pass through a waste water treatment plant.

    Sulfur dioxide may also be removed by dry desulfurisation by injection limestone slurry into the flue gas before the particle filtration.

    NOx is either reduced by catalytic reduction with ammonia in a catalytic converter (selective catalytic reduction, SCR) or by a high temperature reaction with ammonia in the furnace (selective non-catalytic reduction, SNCR). Urea may be substituted for ammonia as the reducing reagent but must be supplied earlier in the process so that it can hydrolyze into ammonia. Substitution of urea can reduce costs and potential hazards associated with storage of anhydrous ammonia.

    Heavy metals are often adsorbed on injected active carbon powder, which is collected by the particle filtration.
    Incineration - Wikipedia, the free encyclopedia
     
  8. Intense
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    Intense Senior Member

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    Consider your home appliances, if you have a gas Natural Gas pr Propane Stove or Dryer. If your adjustments (gas/air ratio) are correct, you should have no yellow in the flames. yellow in the flames or soot on the pots would indicate a dirty burn with high CO output. That is a serious health risk, in a heater with poor ventilation, odorless and deadly. Pilot's burn yellow, but it is minimal, though stove pilots can easily trigger CO Detectors, if they are positioned too close. Just a thought. CO accumulates in the blood and stays there a long while.
     
  9. Big Fitz
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    True, but wood and natural gas are two different things. That's all I'm saying.
     
  10. liebuster
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    liebuster VIP Member

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    You dismissed yourself when you post the bolded above


    Please tell me how .032% CO2 already in the air is going to affect the temp of the earth.

    I think there are better "green house" gases in this world like water vapor
     

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