According to the equation, the equilibrium mixture will contain
- When the temperature is lower (the reaction is exothermic
in the ammonia direction)
- When pressure is higher (4 moles of reactant gas make 2 moles
of product gas)
In practice, the equilibrium is run under conditions of moderate
temperatures and pressure.
Low temperatures affect the equilibrium favourably, but the reaction
would be too slow. Very high pressures, though favouring product
creation, increase the costs of plant construction, and present
a greater risk to plant workers.
With the conditions used, a yield of approximately 20 - 30 % is
achieved from each pass over the catalyst.