Industrial Catalysis

Equilibrium reactions

In this section we use the case study of steam reforming to illustrate some of the factors that chemists must consider when designing an effective catalyst for an industrial process.

The reaction between methane and steam is an equilibrium reaction.

CH4 + H2O

CO + 3H2

 

DH = +251 kJmol-1

This reaction is endothermic.

Using the carbon monoxide

The carbon monoxide produced can also react with steam in another equilibrium reaction.

CO +H2O

CO2 + H2

 

DH = +3.0 kJmol-1

This reaction is slightly exothermic.

Equilibrium position and Le Chatelier's Principle

The position of the equilibrium in the two reactions is affected by a number of factors. A high steam to methane ratio, for example, pushes the equilibrium position towards the products.

The effect of pressure and temperature on the equilibrium position can be predicted using Le Chatelier's Principle.