Disclosed are processes for purifying feed streams containing hydrogen sulfide and sulfur-containing impurities by removing sulfur-containing impurities, such as elemental sulfur and polysulfanes, using solid catalytic sorbents. Also disclosed are processes for producing hydrogen sulfide.

An elemental sulfur recovery unit comprising a thermal unit configured to combust an acid gas feed comprising hydrogen sulfide, an oxygen source, and a fuel gas to create a reaction furnace outlet stream, comprising elemental sulfur, a waste heat boiler configured to capture heat from the reaction furnace outlet stream to create a waste heat boiler effluent, a condenser configured to condense the waste heat boiler effluent to produce a non-condensed gases stream and a condensed stream comprising elemental sulfur, a process gas reheater configured to generate a hot gases stream, a hydrogenation reactor configured to convert the hot gases stream to create a hydrogenation effluent comprising hydrogen sulfide, a process desuperheater configured to cool the hydrogenation effluent to generate a cooled effluent, and an absorber unit configured to absorb the hydrogen sulfide from the cooled effluent to produce a hydrogen sulfide recycle stream and a waste gas stream.

A process for producing hydrogen sulfide from hydrogen and elemental sulfur, comprising: bringing the sulfur into contact with a solid catalyst comprising at least one metal, chosen from metals from groups VIB and VIII of the Periodic Table of the Elements, in metal sulfide form, at a temperature ranging from 120 C. to 160 C.; circulating the mixture of sulfur and catalyst resulting from step (a) in a reaction zone, in which said mixture is brought into contact with hydrogen, the reaction zone having a temperature at the inlet point of the catalyst of greater than or equal to 150 C. and a temperature at the outlet point of the catalyst of less than or equal to 300 C., and a pressure of less than or equal to 3 bar; separating the catalyst and the gaseous effluents containing hydrogen sulfide; and recycling the catalyst to the step of bringing.

The present invention provides methods of forming hydrogen sulfide. The methods include contacting a precursor compound with an unmasking agent; wherein the precursor compound comprises a hydrogen sulfide releasing moiety and a masked nucleophile; and wherein the contacting is conducted under conditions sufficient for cyclization of the precursor compound via lactone or lactam formation; thereby releasing hydrogen sulfide from the precursor compound. Hydrogen sulfide precursor compounds according to Formula I are also described, as well as methods for treating diseases and conditions using hydrogen sulfide precursors. ##STR00001##

The present invention provides methods of forming hydrogen sulfide. The methods include contacting a precursor compound with an unmasking agent; wherein the precursor compound comprises a hydrogen sulfide releasing moiety and a masked nucleophile; and wherein the contacting is conducted under conditions sufficient for cyclization of the precursor compound via lactone or lactam formation; thereby releasing hydrogen sulfide from the precursor compound. Hydrogen sulfide precursor compounds according to Formula I are also described, as well as methods for treating diseases and conditions using hydrogen sulfide precursors. ##STR00001##

Embodiments of the disclosure provide a method and a Claus tail gas treatment system for sulfur recovery. A tail gas stream is fed to a hydrogenation reactor to produce a hydrogenated gas stream by converting sulfur-containing compounds to hydrogen sulfide. The hydrogenated gas stream is fed to a quench tower to produce a quenched gas stream by condensing and recovering liquid water via a water condensate stream. The quenched gas stream is fed to a first stage adsorption unit to produce a first outlet gas stream by separating water via a first byproduct stream from hydrogen sulfide, carbon dioxide, and nitrogen. The first outlet stream is fed to a second stage adsorption unit to produce a second outlet gas stream by separating carbon dioxide and nitrogen via a second byproduct stream. The second outlet stream includes hydrogen sulfide. The second outlet stream can be fed to a Claus unit.

Impurities that are less volatile than carbon dioxide, e.g. hydrogen sulfide, are removed from crude carbon dioxide by processes involving distillation of said crude carbon dioxide in a distillation column system operating at super-atmospheric pressure(s) to produce carbon dioxide-enriched overhead vapor and bottoms liquid enriched with said impurities. Where such processes involve a single heat pump cycle, significant savings in power consumption are realized when the distillation column system is re-boiled by at least partially vaporizing liquid in or taken from an intermediate location in the column system.

A system of enriching acid gas for feeding a sulfur recovery unit includes a contactor configured to separate an acid gas stream into a carbon dioxide rich stream and a purified acid gas stream, where the acid gas stream includes hydrogen sulfide, carbon dioxide, and hydrocarbons; a regenerator in fluid communication with the contactor such that the regenerator is configured to separate the purified acid gas stream to create a hydrogen sulfide rich stream and a hydrogen sulfide lean stream; and a recycle stream conduit fluidly coupled between the regenerator to the contactor and configured to supply at least a portion of the hydrogen sulfide rich stream from the regenerator to the contactor.

A system of enriching acid gas for feeding a sulfur recovery unit includes a contactor configured to separate an acid gas stream into a carbon dioxide rich stream and a purified acid gas stream, where the acid gas stream includes hydrogen sulfide, carbon dioxide, and hydrocarbons; a regenerator in fluid communication with the contactor such that the regenerator is configured to separate the purified acid gas stream to create a hydrogen sulfide rich stream and a hydrogen sulfide lean stream; and a recycle stream conduit fluidly coupled between the regenerator to the contactor and configured to supply at least a portion of the hydrogen sulfide rich stream from the regenerator to the contactor.

A process for recovering sulfur from a tail gas stream comprising the steps of providing a tail gas stream to a chemical looping combustion (CLC) unit, the tail gas stream comprising a sulfide component, providing an oxygen carrier to the CLC unit, the oxygen carrier comprising a calcium carbonate, providing an air stream to the CLC unit, the air stream comprising oxygen, and reacting the sulfide component in the CLC unit with the calcium compound and the air to produce a product effluent, the product effluent comprising calcium sulfate.