3. Chemical Process Industries

Sulfur is converted to sulfur dioxide by burning molten sulfur with dried air in a sulfur burner to yield a 1000-1200\(^\circ\)C gas stream containing 10–12 percent \(\ce{SO2}\). The burner is mounted at one end of a sulfur furnace, and the gas passed through a waste heat boiler at the other end. The gas temperature is reduced to 420-440\(^\circ\)C on leaving the boiler, which produces 40–60 bar steam. Modern sulfuric acid plants are generating 1.7 ton of steam per ton of sulfuric acid production.