Scavenging compounds and compositions useful in reducing sulfide emissions from polymer treated asphalt, such as polyphosphoric acid, are disclosed. The scavengers include hexamethyl-enetetramine, water-free triazine, and water-free 1,3,5-triazine derivatives of formula I. Methods of using the compositions to reduce hydrogen sulfide emissions from asphalt are also disclosed.

Systems and methods for removing hydrogen sulfide from an ammonia stream in the NH3 purification and liquefaction stage of a conventional two-column sour water stripping system using an adsorbent bed.

A method for desulfurization and dezincification of tailings includes the step of passing tap water into a high oxidation reduction electrocatalytic water equipment to reduce the pH value of tap water to 1-2, mixing a specific ratio of the pH value 1-2 acid electrocatalytic water with low-quality high-sulfur iron in the tailings, heating the mixture to let H.sup.+ in the acid electrocatalytic water be reacted with sulfur and zinc in the low-quality high-sulfur iron and to further cause generation of an ion state of hydrogen sulfide gas where the volatilization of water vapor effectively removes the sulfur and zinc elements in the low-quality high-sulfur iron and the hydrogen sulfide gas thus generated is collected.

A method for desulfurization and dezincification of high-sulfur coal includes the steps of passing tap water into a high oxidation reduction electrocatalytic water equipment to reduce the pH value to 1-2, mixing the pH value 1-2 acid electrocatalytic water thus obtained with the high-sulfur coal, and heating the mixture to let H.sup.+ in the acid electrocatalytic water be reacted with sulfur and nitrogen in the high-sulfur coal to cause generation of hydrogen sulfide gas and ammonia where the volatilization of water vapor effectively removes the sulfur and nitrogen in the high-sulfur coal and the hydrogen sulfide and ammonia gases thus generated are collected.

A method for desulfurization and dezincification of high-sulfur coal includes the steps of passing tap water into a high oxidation reduction electrocatalytic water equipment to reduce the pH value to 1-2, mixing the pH value 1-2 acid electrocatalytic water thus obtained with the high-sulfur coal, and heating the mixture to let H.sup.+ in the acid electrocatalytic water be reacted with sulfur and nitrogen in the high-sulfur coal to cause generation of hydrogen sulfide gas and ammonia where the volatilization of water vapor effectively removes the sulfur and nitrogen in the high-sulfur coal and the hydrogen sulfide and ammonia gases thus generated are collected.

An acid gas purification system is described herein that includes a primary membrane system with a CO.sub.2- and H.sub.2S-enriched permeate stream effluent and a hydrocarbon stream effluent; a first compression stage arranged to receive the CO.sub.2- and H.sub.2S-enriched permeate stream and produce a compressed stream; and a cryogenic separation system to receive the compressed stream, the cryogenic separation system including a cooler followed by a fractionator, wherein the fractionator produces a CO.sub.2- and H.sub.2S liquid stream and a hydrocarbon gas stream.

To provide an inorganic solid material that has a hydrogen sulfide sustained releasability at ordinary temperature in the air atmosphere and is capable of being handled safely and a method for producing the same, and a method for generating hydrogen sulfide using the material. A layered double hydroxide having HS? and/or Sk2? (wherein k represents a positive integer) intercalated among layers (sulfide ion-containing LDH) is produced, and the sulfide ion-containing LDH is hermetically housed in a packaging material to provide a package. In generating hydrogen sulfide, the packaging material of the package is opened, and the sulfide ion-containing LDH is exposed to the air atmosphere to sustainably release hydrogen sulfide.

To provide an inorganic solid material that has a hydrogen sulfide sustained releasability at ordinary temperature in the air atmosphere and is capable of being handled safely and a method for producing the same, and a method for generating hydrogen sulfide using the material. A layered double hydroxide having HS? and/or Sk2? (wherein k represents a positive integer) intercalated among layers (sulfide ion-containing LDH) is produced, and the sulfide ion-containing LDH is hermetically housed in a packaging material to provide a package. In generating hydrogen sulfide, the packaging material of the package is opened, and the sulfide ion-containing LDH is exposed to the air atmosphere to sustainably release hydrogen sulfide.

A process for substantially removing hydrogen sulfide from an ammonium sulfate solution. The process involves maintaining the pH of the solution to a range that optimally removes entrained hydrogen sulfide. The hydrogen sulfide is then reacted with sulfites, bisulfites, or sulfur dioxide to form ammonium thiosulfate.

A process for recovering sulfur in a sulfur recovery unit comprising the steps of reacting hydrogen sulfide and oxygen in the reaction furnace at a minimum reaction temperature to produce a reaction effluent; reducing the temperature of the reaction effluent from the minimum reaction temperature to a boiler section outlet temperature to produce a cooled effluent, the cooled effluent comprises hydrogen sulfide, sulfur dioxide, and sulfur-containing contaminants; reacting the hydrogen sulfide, sulfur dioxide, and sulfur-containing contaminants in the catalytic extension to produce a boiler catalytic effluent; reducing the boiler catalytic effluent temperature such that the elemental sulfur condenses to form liquid sulfur and a gases stream; reacting the hydrogen sulfide and sulfur-containing contaminants with the oxygen to produce an oxidizer outlet stream comprises sulfur dioxide; and separating the sulfur dioxide in the scrubbing unit to produce a recycle stream and an effluent gases, the recycle stream comprises sulfur dioxide.