Industrial Catalysis

Manufacture of sulphuric acid

The manufacture of sulphuric acid is a two-stage process. The first stage is the oxidation of sulphur dioxide and it uses a vanadium oxide catalyst.

Summary of conditions and catalyst for sulphur dioxide oxidation

world annual production

greater than 140 million tonnes per year

temperature

700 K

catalyst

V2O5 on a ceramic base

conversion

approximately 99%

   
Uses of sulphuric acid

The two main stages in the manufacture of sulphuric acid.

oxidation of sulphur dioxide

 

2SO2 + O2

2SO3

DH = - 192 kJmol-1 at 700K

absorption of sulphur trioxide

 

SO3 + H2O

H2SO4

DH = - 115 kJmol-1

 

 

 

Main stages in the manufacture of sulphuric acid

More on the catalyst

Catalyst V2O5 on a ceramic base. (The catalyst is in the form of cylindrical pellets, 8mm diameter, 12 mm long, packed into a bed 8 m diameter and 600 mm deep. The catalyst is in more than one bed with cooling between beds. The first bed has a lifetime of about 5 years, a third or fourth bed can last between 15 and 20 years).