What happens to combustion if the mixture is richj
Answers
A rich mixture occurs when the quantity of air available is less than the stoichiometric quantity; this means that there is not sufficient air to burn the fuel. In this simplified approach it is assumed that the hydrogen combines preferentially with the oxygen and the carbon does not have sufficient oxygen to be completely burned to carbon dioxide: this results in partial oxidation of part of the carbon to carbon monoxide. It will be shown in Chapter 12 that the equilibrium equations, which control the way in which the hydrocarbon fuel oxidizes, govern the proportions of oxygen taken by the carbon and hydrogen of the fuel and that the approximation of preferential combination of oxygen and hydrogen is a reasonable one. In this case, to define a rich mixture, ϕ is greater than unity. Then
(10.7)CH4+2ϕ(O2+3.76N2)→(4−3ϕϕ)CO2+2H2O+4(ϕ−1)ϕCO×7.52ϕN2.