In Part I, the use of a gas turbine as the primary combustion stage in a contact sulphuric acid process is examined and a significant advantage in the energy recovery revealed. For a typical case, the net energy recovery as electric power is improved by 60–70 per cent over that possible with simple steam-raising equipment. The overall economics of the concept and the potential for energy savings are discussed in Part II. Whether or not this potential advantage can be realised depends on a number of factors including fuel feed and combustion chamber design. However, the most serious uncertainty is the corrosion resistance of the turbine materials to an atmosphere of sulphur dioxide, oxygen and nitrogen. These factors are examined in Part III.