Contact Section
May 8, 2003

Introduction

In the late 1800’s and early 1900’s, the rapid advancement of industry gave rise to a fast growth in demand for sulphuric acid.  The ‘lead chamber’ process was up to that point the main method of sulphuric acid production.  Research was undertaken to develop a process whereby sulphur dioxide (SO₂) and oxygen (O₂) are reacted together in the presence of a catalyst to form sulphur trioxide (SO₃).  The so-called ‘contact process’ came into initial use with platinum as the catalyst on which the conversion of SO₂ to SO₃ took place.  Platinum catalysts are highly active but suffered from high costs and were easily poisoned by contaminants such as As₂O₃.  In 1913, BASF patented a catalyst using vanadium pentoxide and alkali metal oxides on porous carriers containing silica.  In 1915, a commercial scale plant began production of sulphuric acid using vanadium catalyst.  This was the beginning of the modern contact process.

The contact section of a modern day acid plant comprises all the dry gas handling equipment including the blower, gas-to-gas heat exchangers, converter, ducting and stack.