The regeneration of the absorption/adsorption systems is accomplished in different ways, mainly by physical processes such as degassing at high temperatures or low pressures, The H2S is generally converted to elemental sulfur in the Claus oven. Here some of the H2S is totally oxidized to SO2, which is reduced to sulfur with additional H2S in a following step. This second step requires a catalyst, which is frequently based on Al203.