Module 2: Thermodynamics of Combustion
  Lecture 11: Chemical Equilibrium
 


Procedure for Determining Equilibrium Composition

Equilibrium products can be estimated by adopting the following steps

Step 1: Identify probable equilibrium species
Step 2: Identify equilibrium reactions scheme
Step 3: Find out equilibrium constant
Step 4: Strike balance for elemental conservation
Step 5: Strike overall mass conservation
Step 6: Solve all equations by iterative method (Newton- Raphson Method)

For a ideal gas mixture, Gibbs function of i th species is given by



-Gibbs function per mole of ith species.
-Partial pressure of ith species.
-Temperature
-Universal gas constant

Gibbs function for a ideal gas mixture

At equilibrium,

   
In the above equation, (Since pressure remains constant)