Contemplated systems and methods for removing polysulfides and hydrogen sulfide from liquid sulfur of a Claus plant include (a) physically separated steps of catalytic decomposition of polysulfides and gas stripping, or (b) use of the stripping gas as the continuous phase in a packed column with decomposition catalyst to so avoid catalyst attrition.

A process for preparing sulfuric acid may involve melting elemental sulfur in a melting stage to give molten sulfur. Sulfuric acid is subsequently produced from the molten sulfur. Further, sulfur-containing offgases formed in the melting stage may be subjected to oxidation in a supplementary oxidation stage in which sulfur-containing components of the offgases are oxidized to sulfur dioxide. The process may further involve processing the sulfur dioxide to give at least one reaction product. The melting stage may be operated without emissions by processing all of the offgases from the melting stage. An apparatus may be employed for carrying out such a process.

Embodiments of the invention are directed to a sulfur recovery system that utilizes a degassing system for degassing liquid sulfur. The degassing system includes a degassing device vessel, a pressure equalizer, a motive force device, a sulfur cooler, and/or a process gas cooler. The degassing system may be located within or outside of the sulfur recovery unit and utilizes the process gas from the sulfur recovery unit. The degassing device may receive liquid sulfur and process gas, which are passed through a catalyst, which along with the process gas, degases the liquid sulfur. As such, the degassing system when used within the sulfur recovery unit degasses the liquid sulfur to reduce off-gassing of dangerous hydrogen sulfide during storage and transportation without the need for additional equipment to degas the liquid sulfur during or after the sulfur storage.

Processes and systems for degassing liquid sulfur may include mixing a gas, such as air, with a liquid sulfur mixture comprising sulfur, hydrogen sulfide, and hydrogen polysulfides to form a sulfur-gas mixture. The sulfur-gas mixture may then be transported to a separator, storage vessel or storage tank for separating the sulfur-gas mixture.

A method and system for liquid sulfur degassing is disclosed. The method and system generally involve degassing liquid sulfur in a degassing vessel, and the level of the liquid sulfur in the degassing vessel is controlled in the degassing vessel by determining the level of liquid sulfur in the degassing vessel.

A horizontal sulfur condenser may include an exterior casing with a plurality of condenser tubes arranged longitudinally within the casing, a liquid sulfur reservoir at a longitudinal end within the exterior casing, and an internal baffle that protrudes into the liquid sulfur reservoir from the surface. The lowest of the plurality of condenser tubes is parallel to a wall of the exterior casing. A Claus process gas inlet is proximate a first end of the plurality of condenser tubes, which are arranged horizontally but are positioned vertically above the sulfur reservoir. A liquid sulfur outlet is located at the liquid sulfur surface. The baffle creates multiple chambers above the sulfur reservoir, such as a first chamber defined by the exterior casing and the baffle to receive condensed Claus sulfur in the liquid reservoir, and a second chamber defined by the exterior casing and the baffle to receive degassed liquid sulfur.

Contemplated systems and methods for removing polysulfides and hydrogen sulfide from liquid sulfur of a Claus plant include (a) physically separated steps of catalytic decomposition of polysulfides and gas stripping, or (b) use of the stripping gas as the continuous phase in a packed column with decomposition catalyst to so avoid catalyst attrition.

A novel system and method for degassing H.sub.2S and H.sub.2S.sub.x from liquid sulfur (sulphur) is disclosed. The system includes a degassing vessel with a plurality of cells. The cells include a sparging gas mat with a perforated surface at the bottom of the cell to allow the release of air bubbles (or sparging gas) into the cells. A catalyst may be used during the process. As a result, hydrogen sulfide and hydrogen polysulfide are efficiently and effectively removed from the liquid sulfur.

A process of producing degassed liquid sulfur using agitation gas to agitate the liquid sulfur being degassed while in contact with a degassing catalyst. Process gas may be blended with the agitation gas wherein the process gas contains H.sub.2S to accomplish substantial degassing rendering the liquid sulfur much safer in storage and transportation.

A method and system for liquid sulfur degassing is disclosed. The method and system generally involve degassing liquid sulfur in a degassing vessel, and the level of the liquid sulfur in the degassing vessel is controlled in the degassing vessel by determining the level of liquid sulfur in the degassing vessel.