Apparatus and process for recovering elemental sulfur from a H2S-containing waste gas stream are disclosed. The apparatus preferably comprises a first reaction zone (30) for carrying out the catalytic partial oxidation of H2S, a second reaction zone for (40) the catalytic partial reduction of any incidental SO2 produced in the first reaction zone (30), and a cooling zone (320) including a sulfur condenser (380). According to a preferred embodiment of the process, a mixture of H2S and O2 contacts a catalyst in the first reaction zone very briefly (i.e, less than about 200 milliseconds) producing primarily S0 and H2O. Some SO2is also present in the first stage product gas mixture. A reductant gas (e.g, CO, or CH4 or natural gas) is fed together with the first stage product gas mixture to a second catalytic reaction zone where the partial reduction of the SO2 component to elemental sulfur and CO2 is carried out. |