The Institute Francais du Petrole has developed a process for reacting H2S with SO2 to produce water and sulfur. The overall reaction is 2H2S + 862 -» 2H2O + 3S. Figure 7-10 is a simplified diagram of the process. This process involves mixing the H2S and SO2 gases and then contacting them with a liquid catalyst in a packed tower. Elemental sulfur is recovered in the bottom of the tower. A portion of this must be burned to produce the SO2 required to remove the H2S. The most important variable is the ratio of H2S to SO2 in the feed. This is controlled by analyzer equipment to maintain the system performance.