Wind Farms

[bernardgreen]

There are various forms of coal and various ways of extracting the hydro-carbon materials. Some coals were better for producing town case and others were better for coke ovens producing high grade coke for coke ovens producing steel in blast furnaces. Other coals were best for gas production. The coke from a gas producing plant was not suitable for blast furnances and high grade steel.

 

[JohnW2]

How much different is one hydrocarbon to another?

...So switching from coal to natural gas, you switch from C + O2 = CO2 to CH4 + 2O2 = CO2 + 2H2O. So for every carbon atom you turn into CO2, with natural gas you also add the energy from turning 4xH2 into H2O (less some energy required to break up the input molecules). Result, for the same energy output, you need less carbon input.
If you want that in terms of CO2 out per fuel in : For carbon it's 46 (2x16 + 14) units of CO2 for each 14 units of carbon, so 3.29 kg of CO2 per kg of coal. For methane, it's 46 units of CO2 for 18 units of fuel, so 2.56 kg of CO2 per kg of gas, plus 2kg of water. I'll leave someone else to lookup the relative energy outputs.

On the basis of the first calorific value figures I found when I asked Mr Google, I've had a quick look ...

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• JohnW2
• 8 Jul 2013
• 1

If I've got it right, the short answer to BAS's question seems to be that there is not much difference between different hydrocarbons in terms of 'energy per carbon' but that there is a substantial (surprising in magnitude to me) difference between any of them and carbon itself. As one would expect, as one 'moves up' the family of straight-chain hydrocarbons, the 'amount of carbon per energy' gradually increases (since carbon becomes a progressively higher proportion, by weight, of the hydrocarbon), but even when one gets up to C8H18 (84% carbon by weight), the figure is still not much more than half the figure for carbon itself.

Kind Regards, John