Combustion #1 – Fuels

Hey, it’s going to be increasingly important that you can link reduced carbon emissions to energy savings.  So let’s learn how to calculate this.

I’m going to start by listing typical raw materials and fuels.  Fuels contain energy that is released when the chemical bonds holding hydrogen and carbon in the fuel are broken and these elements are able to recombine with free oxygen from the atmosphere, which results in the release of heat and the production of carbon dioxide.  The list below also shows the approximate amount of energy that is released when a pound (technically a pound-mass, which weighs a pound here on good old earth) of the material is burned.

Heat of Combusion for Raw Materials

Carbon                         C                      14,093 Btu/lb

Hydrogen                     H2                   61,095 Btu/lb

Carbon Monoxide        CO                     4,347 Btu/lb

Methane                       CH4                 23,875 Btu/lb

Ethane                         C2H4               22,323 Btu/lb

Propane                       C3H8               21,669 Btu/lb

n-Butane                      C4H10             21,271 Btu/lb

Ammonia                     NH3                   9,667 Btu/lb

Gasoline                      C8H18             19,000 Btu/lb (approx)

Heating value of fuel oil runs as follows:

Kerosene         134,000 Btu/gal

No. 2               134,000 Btu/gal   (138,000 Btu/gal to MGH)

No. 4               144,000 But/gal

No. 5               150,000 Btu/gal

No. 6               143,800 Btu/gal – low sulfur (0.3%)

No. 6               152,000 Btu/gal – high sulfur (2.7%)

Gasoline          109,000 to 125,000 Btu/Gal  – 114,000 average.

Gasoline weighs approximately 6 pounds per gallon.  Heavy oil (No. 6) weighs approximately 8 pounds per gallon.  The lighter oils run in between.  This means that gasoline and fuel oils run in the neighborhood of about 20,000 Btu per pound, similar to the other hydrocarbons listed above.

I find having a list like this to be very handy.

An upcoming post will show how the combustion equations can be used to determine the energy release and carbon dioxide emissions associated with burning different kinds of fuels.

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