The disposal of sulfurous gas and sulfur recovery using the Claus process

For typical sulfurous gas compositions, sulfur recovery at Claus plants can be as high as:

• 95-96%- with one thermal stage and two catalytic stages;
• 97-98%- with an additional (third) catalytic stage.

To attain a higher sulfur recovery, tail gas clean-up units must be built. The techniques used depend on allowable sulfurous compound emissions.