2. Thermodynamic aspects

2.1 A few orders of magnitude for energy

When combustible materials burn in the presence of oxygen, they release stored chemical energy in the form of heat. The power of combustion is the amount of energy released per unit of time. Typically, a common solid or liquid fuel material (composed essentially of a combination of hydrogen and carbon atoms) has a calorific value of 15 to 50 MJ/kg, a gaseous fuel 50 to 125 MJ/kg [SE 2 050] . The chemical reaction of combustion is always essentially the combination of oxygen atoms with the hydrogen and carbon atoms of the material, and for this type of reaction, each kilogram of oxygen mobilizes around 13.1 MJ. Moreover, in practice, combustion is strongly impeded...