I hope I’m wrong.
But I have this sneaking suspicion that some of the people who question climate change partially base this on a belief that burning fossil fuel does not necessarily add carbon dioxide to the atmosphere. That this is somehow speculative or a matter of debate.
There is no debate on this matter.
Coal, oil and natural gas liberate heat when the carbon in their composition combines with free oxygen in the air to produce CO2. There is no way around this fact. (Okay, it’s true that the combusted hydrogen in hydrocarbons also liberates heat, but we aren’t going to worry about that for our present purposes since the combustion byproduct of hydrogen is just water vapor.)
So, while you may not believe that rising carbon dioxide levels contribute to climate change, and while you may even be treated with deference when expressing this opinion, to assert that mankind is not contributing to the elevated CO2 levels seen in the atmosphere is a preposterous claim that denies fundamental facts about combustion.
We’re putting CO2 up there in the atmosphere without question.
A couple of interesting facts.
The atomic weight of carbon is 12. The atomic weight of oxygen is 16. (you may be asking, 12 and 16 what? ounces? pounds? butterfly wings? Turns out it doesn’t matter for our purposes, as I will show…)
What that means is that when fuel is burned and converts from carbon to carbon-dioxide, the weight of the carbon dioxide is almost 4 times heavier than the carbon that was burned. Why? Look at the atomic weight ratios
Carbon (12) + 2 Oxygen (16+16) ==> Carbon Dioxide (12+16+16)
Ratio of CO2 weight divided by the weight of the burned carbon is 44/12 = 3.7
What this means is that a ton of coal (which is mostly carbon) will result in about 3.7 tons of carbon dioxide emissions when burned. This is not a theory. This is not just possible. This is non-negotiable.
You may be wondering about the hydrogen in fuels such as natural gas or petroleum. If you look at natural gas, the chemical composition is mostly CH4. The combustion equation is pretty simple:
CH4 + 2O2 ==> CO2 + 2H2O + liberated heat (about 22,000 Btu per pound of natural gas)
Note that the H2O combustion product is just water vapor, which is benign. This makes pure hydrogen a very attractive fuel, at least in theory.
Also note that when we discuss fuels, we are discussing something different from energy or power. Fuels are repositories of stored energy, and the rate at which we burn fuels determines how much power is generated. Some common combustion fuels include:
- Fuel Oil
- Natural Gas
Note that the energy content of fuels is pretty well defined. For instance, coal might house 25 million Btu of energy per ton, depending on the coal type. Somewhere along the line I will provide more detailed fuel energy content data and show how the combustion calculation are performed.
Right now I’m just getting some preliminary stuff out of the way as I try to figure out if this blog is going to have any value to me, let alone anyone else.