Abstract: A process for recovering and purifying vanadium found in petroleum coke is disclosed. Coke containing V and sulfur is charged to a molten metal bath and dissolved to form a molten metal bath with dissolved carbon, dissolved V metal and dissolved sulfur. At least a majority of the dissolved sulfur is released as H2S by maintaining reducing conditions in the bed, by maintaining a high concentration of dissolved carbon or addition of steam or hydrogen rich hydrocarbon such as methane or some combination of these approaches.

Abstract: An installation and a method are described for the treatment of a gas containing hydrogen sulphide, the gas (1) being washed in a first gas scrubber (5) with an alkaline wash liquid and the spent wash liquid (4) being treated in an aerobic reactor (6) with oxygen in the presence of sulphide-oxidising bacteria and the effluent (9) from the aerobic reactor (6) being re-used as wash liquid (3) and the elementary sulphur formed during the treatment with oxygen being removed from the effluent (19), the effluent (13) from which sulphur has been removed being treated in an anaerobic reactor (17) with sulphate-reducing bacteria and returned to the aerobic reactor (6). The installation and the method can also be used for simultaneous removal of SO.sub.2, COS, CS.sub.2, NH.sub.3 and HCN.

Abstract: A method and an apparatus produce a product in at least one phase from an organic component in a feed gas stream. The method includes forming a process zone including a process molten bath and a process gas space disposed over the process molten bath. Molten droplets of said molten bath are then dispersed across the process gas space. The feed gas stream is then directed into the process gas zone, wherein the organic component is exposed to said molten droplets, thereby converting at least a portion of the organic component to a product in at least one phase.The apparatus of the invention comprises a reactor which includes a gas formation section, having a feed inlet, and means for retaining a solid feed component within the gas formation section. The apparatus also includes a process section, disposed in the reactor, having a process gas space, a gas outlet and a process molten bath disposed therein.

Abstract: The invention provides methods for purifying hydrogen sulfide gas having impurities therein. In one exemplary method, the hydrogen sulfide gas is purified by passing the gas through a filter media, with at least some of the impurities being trapped within the filter media. A catalyst may also be provided to break down some of the impurities to hydrogen sulfide and sulfur, so that the sulfur may be trapped and collected within the filter media.

Abstract: In addition to ash and coke, the gasification residue contains alkaline earth metal sulfide and alkaline earth metal oxide because desulfuring agents have been supplied to the gasifier. At temperatures from 5.degree. to 80.degree. C. the gasification residue is mixed with an acid-containing aqueous solution so that a gas which is rich in H.sub.2 S is produced. Ash, coke, and alkaline earth metal salt are supplied to a flotation zone, in which coke is separated. A solid residue which contains ash and alkaline earth metal salt is withdrawn from the flotation zone. Carbonic acid or dilute sulfuric acid is preferably used as an acid.

Abstract: A process is provided for treating the solid reaction by-products of lith and sulfur hexafluoride. Lithium in the by-product solid waste is converted to lithium hydroxide. Lithium sulfide in the by-product is converted to lithium hydroxide. Lithium sulfide in the by-product is reacted with an acid to form a water soluble salt and hydrogen sulfide. The hydrogen sulfide is converted to an alkali metal sulfate. Solid aluminum oxide and lithium fluoride are recovered as a feed in the production of aluminum. Remaining lithium salts in solution are converted to lithium carbonate.

Abstract: A method for reducing contaminant concentrations in a fluid stream including the steps of forming a metal-complexed material having a surface suitable for exchange with the contaminant, contacting the fluid stream with the metal-complexed material, immobilizing at least a portion of the contaminant on the surface of the metal-complexed material, and regenerating the metal-complexed material so as to remove the contaminant from the surface of the metal-complexed material. The metal-complexed material is formed by the encapsulating of a core of ferromagnetic material with an ion exchange material. The metal-complexed material is magnetically affixed to a metallic mesh retaining surface.

Abstract: This invention relates to novel cobalt and molybdenum promoted titania and nickel and molybdenum promoted titania catalysts, and molybdenum promoted titania catalysts containing mixtures of cobalt and nickel. The invention also relates to a process for using the catalysts to convert sulfur in the form of carbon sulfides and nitrogen present as hydrogen cyanide to hydrogen sulfide and ammonia respectively. The catalysts and process of the present invention are effective even when oxygen in concentrations up to about 2 volume %, preferably 1.0 volume %, (dry basis) is present. The catalyst comprises about 0.5 to about 5%, by weight, cobalt oxide (CoO), nickel oxide (NiO), or mixtures thereof; about 1.5 to about 15%, by weight, molybdenum trioxide (MoO.sub.3); and about 70 to about 98%, by weight, titanium dioxide (TiO.sub.2).

Abstract: An apparatus and process for the removal and recovery of sulfides from tannery waste water or liquor. The apparatus comprises a closed vessel, the sulfide-bearing liquor is introduced into a first or acidulation zone of the vessel and mixed with acid to decrease the pH, preferably to a value below 4.0, and generate hydrogen sulfide. The acidified liquor is then overflowed into a second or desorption zone of the vessel and slowly agitated and conveyed through the second zone by disc conveyors to release the hydrogen sulfide gas from the liquor. A slight vacuum is drawn on the vessel causing the released hydrogen sulfide gas to be drawn into a third reaction zone of the vessel, where the gas combines with sodium hydroxide solution to form sodium sulfhydrate. The effluent from the second zone can be filtered or dewatered and the filtrate discharged to a disposal site while the proteinaceous solids can be recovered for use as fertilizer.

Abstract: Sulfur compounds poison catalysts, such as the anode catalysts and reformer catalysts within molten carbonate fuel cell systems. This poisoning is eliminated using a sulfur scrubber 29 located prior to the inlet of the cathode chamber 13. Anode exhaust 19 which contains water, carbon dioxide and possibly sulfur impurities, is combined with a cathode exhaust recycle stream 22 and an oxidant stream 25 and burned in a burner 33 to produce water, carbon dioxide. If sulfur compounds are present in either the anode exhaust, cathode exhaust stream, or oxidant stream, sulfur trioxide and sulfur dioxide are produced. The combined oxidant-combustion stream 27 from the burner 33 is then directed through a sulfur scrubber 29 prior to entering the cathode chamber 13. The sulfur scrubber 29 absorbs sulfur compounds from the combined oxidant-combustion stream 27. Removal of the sulfur compounds at this point prevents concentration of the sulfur in the molten carbonate fuel cell system.

Abstract: An improved method of reducing the concentration of carbonyl sulfide in a hydrocarbon gas containing carbonyl sulfide, which method comprises (a) feeding the hydrocarbon gas containing carbonyl sulfide to a hydrolysis section to contact the hydrocarbon gas with hot aqueous absorbent to heat the hydrocarbon gas to form hydrolysis section effluent absorbent and hydrolysis section effluent gas containing carbon dioxide and hydrogen sulfide and having a lower concentration of carbonyl sulfide than the hydrocarbon gas; (b) withdrawing and cooling the hydrolysis section effluent absorbent to form a cool aqueous absorbent; (c) cooling the hydrolysis section effluent gas in a cooling section by contacting the hydrolysis section effluent gas with the cool aqueous absorbent to form warm aqueous absorbent and a cooling section effluent gas containing hydrogen sulfide and carbon dioxide; (d) heating the warm aqueous absorbent to form hot aqueous absorbent; (e) feeding the hot aqueous absorbent to the hydrolysis section;

Abstract: Binary rare earth/sulfur or transition metal/sulfur compounds, e.g., the higher sulfides or sesquisulfides of the rare earths, are prepared by confinedly reacting either a rare earth compound, e.g., an oxide, carbonate or hydroxide, or a transition metal oxide, with a carbon compound of sulfur in gaseous state, e.g., CS.sub.2, within a sealed enclosure.

Abstract: A method and apparatus for the hydrothermal treatment of a catalytic polyvalent metal redox absorption solution, after absorption of the H.sub.2 S from an H.sub.2 S containing gas stream, to avoid substantial buildup of thiosulfate salts, cyanide salts, and cyanide complexes in the catalytic polyvalent metal redox solution. The method and apparatus of the present invention is particularly useful for treating gas streams containing both H.sub.2 S and HCN concurrently for destruction of the cyanide salts and cyanide complexes and conversion of H.sub.2 S and by-product salts to elemental sulfur.

Abstract: The present invention relates to a process for the separation of sulphur and sodium compounds from a hot process gas generated during gasification of spent liquor from the kraft pulping industry, through contact with hydrogen sulphide ion and hydroxide ion containing alkaline liquids in two or more stages, whereby the process gas in a first stage passes through a venturi throat and/or liquid trap where it is brought into contact with an alkaline washing liquid, whereby melt droplets in the process gas are separated from the gas flow and drawn off as an aqueous solution, whereby the process gas in a subsequent washing stage is brought into contact with a finely dispersed washing liquid containing hydroxide ions and hydrogen sulphide ions with a molar ratio greater than 4:1.

Abstract: The present invention relates to a process for the manufacture of hydrogen sulfide by reacting sulfur and hydrogen which comprises two hydrogenation reactions. The first hydrogenation reaction of the present invention comprises the steps of supplying hydrogen gas in a reactor containing sulfur at least a part of which is in a liquid phase at a temperature of not lower than 250.degree. C., and reacting the liquid sulfur and the hydrogen gas to produce a crude hydrogen sulfide effluent gas in the reactor. The sulfur vapor contained in the effluent gas is further reacted with fleshly added hydrogen gas in the second hydrogenation reaction to further concentrate the resulting hydrogen sulfide.

Abstract: The removal of sulphides from gas streams while using a solid absorbent containing tin, tin oxides or mixtures thereof and optionally a stabilizing component consisting of nickel, copper, cobalt, iron or oxides thereof takes place by contacting the sulphide-containing gas stream with the solid absorbent, which is expediently in the form of a carrier with the tin component and the stabilizing component; hereby the absorbent is sulphided and the gas stream desulphided. Subsequently the sulphided absorbents are regenerated by being contacted with a stream of steam. The regeneration process employed is substantially thermoneutral so that superheating and consequent sintering of the absorbent is avoided; moreover it is not necessary to operate at low temperatures, whereby the formation of sulphates as a by-product is avoided.

Abstract: A method and apparatus for treating a catalytic polyvalent metal redox absorption solution, after absorption of H.sub.2 S from a gas, in a first hydrothermal treatment, to separate the polyvalent metal, for example as a polyvalent metal sulfide precipitate, and thereafter treating the redox solution in a higher temperature hydrothermal treatment to decompose thiosulfate salts and, if present, thiocyanide and other cyanide salts and metal-cyanide complexes to decompose the salts and complexes to molecules that can be treated in the H.sub.2 S-absorption process for recovery of sulfur and alkali values.

Abstract: A catalytic polyvalent metal redox solution can be recovered and re-used in a catalytic polyvalent metal redox solution H.sub.2 S-removal, sulfur production process by interposing a closed loop evaporator/condenser process and apparatus in the sulfur washing/filtering/recovery process and apparatus so that wash water used to purify the sulfur, and any polyvalent metal redox solution recovered from the sulfur melter are fed to an evaporator to concentrate the redox solution to a concentration capable of effective absorption of H.sub.2 S, and the water evaporated in the evaporator is condensed as pure water for use in washing and/or filtering the recovered sulfur.

Abstract: A process for converting carbon disulfide (CS.sub.2) to hydrogen sulfide (H.sub.2 S) in mixtures of H.sub.2 S and CS.sub.2 is provided. The H.sub.2 S/CS.sub.2 mixture is combined with water to form a hydrolysis feed mixture. The hydrolysis feed mixture is passed through a hydrolysis reactor containing e.g., an alumina-based catalyst, wherein a substantial portion of the CS.sub.2 is converted to additional H.sub.2 S. A vapor product comprising H.sub.2 S, CO.sub.2, unreacted H.sub.2 O, unconverted CS.sub.2 and sulfur is formed by the hydrolysis reaction. The vapor product is cooled to form a H.sub.2 S/CO.sub.2 vapor phase and a sour water condensate phase. The H.sub.2 S/CO.sub.2 vapor phase is separated from the sour water condensate phase and subsequently recovered. The sour water condensate phase, which contains small amounts of solid sulfur particles, is optionally then combined with additional CS.sub.2 and decanted to form a sulfur-free sour water layer and a CS.sub.2 layer containing dissolved sulfur.

Abstract: Sulfur oxides are removed from gases by contact with a composition containing 3 wt % potassium and 1 wt % thorium on alumina.

Abstract: A process is described for converting carbon oxylsulfide and/or carbon disulfide, possibly in combination with hydrogen cyanide, O.sub.2 and/or SO.sub.2 in a reducing CO containing gas stream by the catalytic hydrolysis of COS and CS.sub.2, followed by the removal of H.sub.2 S, present and formed, from the gas stream. According to the invention, the process is characterized by(a) a first stage comprising converting a portion of the CO present with water in the presence of a catalyst with simultaneous or subsequent hydrogenation of any O.sub.2 and/or SO.sub.2 that may be present;(b) a second stage comprising catalytically hydrolysing COS and/or C.sub.

Abstract: Catalysts susceptible to deactivation by free oxygen or to reactions involving free oxygen are protected by scavenging the oxygen in the presence of an oxidation catalyst, so as to remove commingled oxygen from the reactants to be converted in the presence of the catalyst suscepticle to oxygen attack.

Abstract: Method and devices for the selective removal of H.sub.2 S from an H.sub.2 S-containing gas by contacting the gas in an absorption column with an H.sub.2 S-selective absorbent liquid and transferring the H.sub.2 S-charged absorbent liquid to the upper part of a second column. The charged absorbent liquid then travels to a regeneration zone at the bottom of the column, where it is heated to a temperature at which the absorbent liquid is vaporized and the H.sub.2 S is released.The regeneration zone temperature causes the absorbent liquid vapor to strip the H.sub.2 S back to the upper part of the column where it forms an equilibrium with the H.sub.2 S-charged absorbent liquid at a temperature not more than 30.degree. C. higher than the injection temperature of the absorbent liquid in the absorption column, which equilibrium temperature is maintained by the temperature in the regeneration zone. The H.sub.2 S-enriched vapor formed at the equilibrium point is then tapped.

Abstract: Method for the selective removal of H.sub.2 S from a H.sub.2 S-containing gas by operating in a single column (1) comprising an upper absorption zone (11) and a lower regeneration zone (12) separated by a medial enrichment zone (17). A selective absorbing and regeneratable liquid capable of absorbing H.sub.2 S is introduced at the upper portion of the column and flows successively into the zones (11) and (17) and finally into (12). The absorbing liquid meets the gas to be treated, which is injected through a conduit (9), in the zone (11) while the regenerated absorbing liquid is tapped at the bottom (4) of the column and brought back through a conduit (5) into said zone (11). At the head (2) of the column, a gas having a reduced content of H.sub.2 S is discharged and by means of a system (18) provided in the zone (17) an acid gas fraction rich in H.sub.2 S is tapped. Application to the production of a highly H.sub.2 S enriched gas effluent from a gas containing H.sub.2 S and an appreciable quantity of CO.sub.

Abstract: This invention is a regenerable process for producing elemental sulfur from SO.sub.2 initially contained in a dilute gas source by: (1) absorbing the SO.sub.2 in a concentrated Na.sub.2 SO.sub.3 solution to convert most of the Na.sub.2 SO.sub.3 to Na.sub.2 S.sub.2 O.sub.5 ; (2) separating one third of the absorbed SO.sub.2 ; (3) reacting the residual mixture with solid NaHCO.sub.3 to form gaseous carbon dioxide used in a subsequent step and a slurry composed of solid Na.sub.2 SO.sub.3 suspended in a Na.sub.2 SO.sub.3 solution; (4) separating solid Na.sub.2 SO.sub.3 from the solution which is recycled to (1) above; (5) reducing solid Na.sub.2 SO.sub.3 to Na.sub.2 S; (6) reacting the Na.sub.2 S with H.sub.2 O and CO.sub.2 to form solid NaHCO.sub.3 which is recycled to (3) above and gaseous H.sub.2 S; (6) reacting gaseous H.sub.2 S with SO.sub.2 separated in (2) above to form water and elemental sulfur.

Abstract: Gases such as nitrogen and natural gas are depleted of contaminating mercury by contacting the gas first with an aqueous solution of sodium polysulfide and subsequently contacting the effluent gas with a cobalt salt, for example, cobalt chloride. The effluent gas subsequently treated as desired to remove moisture and any other contaminants present.

Abstract: A process for the recovery of alcohols and hydrogen sulfide from a thiophosphate containing mixture is disclosed.

Abstract: A process for removing SO.sub.x pollutants from a stack gas by (1) absorbing the SO.sub.x pollutants into an aqueous absorbent containing a formate compound and (2) regenerating the spent absorbent containing dissolved SO.sub.x compounds by contact, in the presence of added formate anion, with a water-insoluble, solid substance containing one or more tertiary amine functional groups. Nitrogen monoxide is removed by providing in the aqueous absorbent an iron(II) chelate, such as a chelate of ferrous ion with ethylenediaminetetraacetic acid. Regeneration of the spent absorbent containing absorbed NO is accomplished under the same conditions as for spent absorbents containing absorbed SO.sub.x compounds. SO.sub.x and NO pollutants dissolved in the absorbent are, during regeneration, converted to hydrogen sulfide and nitrogen, respectively.

Abstract: An SO.sub.2 -containing gas, in particular, pre-stage gas for the Claus reaction to recover sulfur can effectively be purified by removing NH.sub.3 contained therein using a TiO.sub.2 catalyst.

Abstract: This invention relates to a method for catalyzing the reactionsQZ+H.sub.2 X.fwdarw.QZX (1) psandQZX.fwdarw.QZ+H.sub.2 X (2)wherein Q=C or N;Z=O or S;X=O, S, NH or NR;R=C.sub.1 to C.sub.8 alkyl which may be linear, branched or cyclized,which comprises:contacting at least one polydentate nitrogen-containing chelating agent complexed with a metal atom with the reactants of one of said reactions, wherein said contacting takes place in the presence of a means for oxidizing when reaction (1) is catalyzed and in the presence of a means for reducing when reaction (2) is catalyzed.

Abstract: The invention provides a method and apparatus for measuring the sodium sulfide content of liquid industrial process streams. According to this method, a sample of the liquid is passed through a heated filter to remove solids and reduce viscosity and a portion of the sample is then mixed with carbon dioxide to generate hydrogen sulfide gas. The hydrogen sulfide gas is separated from the reacted liquid sample, and a portion of the gas is mixed with dilution air and then analyzed quantitively for hydrogen sulfide.

Abstract: Waste containing sulfur and nickel sulfide is heated to volatilize sulfur and reacted with hydrogen chloride to form nickel chloride.

Abstract: A process for the recovery of sulfur from sulfur-bearing ores employing an aqueous leaching solution containing calcium monosulfide, calcium hydrosulfide or mixtures of such calcium sulfide species. The sulfur ore is contacted in an extraction zone with the aqueous leaching solution under conditions to solubilize sulfur from the ore in the form of calcium polysulfide. Preferably, the extraction step is carried out at an elevated temperature. The loaded leaching solution is recovered from the extraction zone and applied to a sulfur-production zone. Here the loaded solution is contacted with hydrogen sulfide under conditions to react the hydrogen sulfide with the calcium polysulfide to produce calcium hydrosulfide and elemental sulfur. The calcium hydrosulfide solution is recycled for use as leaching solution in the sulfur extraction zone.

Abstract: Spent flux containing calcium oxide and calcium sulfide, recovered from the reduction of iron ore, is carbonated, as an aqueous slurry, in two stages, with the first stage being operated at a pH to prevent reaction of calcium sulfide, and the second stage being operated at a pH at which calcium sulfide is reacted to produce an effluent gas containing hydrogen sulfide.

Abstract: There is disclosed a process for the production of carbon disulfide and hydrogen sulfide from a particulate carbon source. In one embodiment, an oxygen containing gas is reacted with a particulate carbon source in a one step process so as to provide the temperatures necessary for the reaction of the particulate carbon source with sulfur to produce carbon disulfide. In another embodiment, a source of hydrogen is introduced along with the oxygen containing gas and sulfur so as to produce hydrogen sulfide in a single step process.

Abstract: A process for producing a low-sulfur content hot reducing gas stream comprising (a) contacting a sulfur bearing hot reducing gas stream with a desulfurizing agent comprising a desulfurizing fixed bed of solid particles comprising calcium oxide to thereby produce a low-sulfur content hot reducing gas stream and a calcium sulfide composition, then (b) contacting said calcium sulfide composition with an oxidizing gas composed of CO.sub.2, H.sub.2 O and O.sub.

Abstract: A process for removing SO.sub.x pollutants from a stack gas by (1) absorbing the SO.sub.x pollutants into an aqueous absorbent containing a formate compound and (2) regenerating the spent absorbent containing dissolved SO.sub.x compounds by contact, in the presence of added formate anion, with a water-insoluble, solid substance containing one or more tertiary amine functional groups. Nitrogen monoxide is removed by providing in the aqueous absorbent an iron(II) chelate, such as a chelate of ferrous ion with ethylenediaminetetraacetic acid. Regeneration of the spent absorbent containing absorbed NO is accomplished under the same conditions as for spent absorbents containing absorbed SO.sub.x compounds. SO.sub.x and NO pollutants dissolved in the absorbent are, during regeneration, converted to hydrogen sulfide and nitrogen, respectively.

Abstract: Process and composition for removing H.sub.2 S and like sulfides from gas streams by contact with a substituted aromatic nitrile having an electron-attracting substituent on the aromatic ring at least as strong as halogen (e.g., isophthalonitrile) and an organic tertiary amine in an inert organic solvent such as N-methyl-2-pyrrolidone.

Abstract: The removal of sulfur oxide (particularly sulfur dioxide) from a fluid stream, such as the tail gas from a sulfur process, is accomplished by contacting such fluid stream with a catalyst composition comprising zinc titanate and a promoter in the presence of a hydrogen donor.

Abstract: The method for the preparation of hydrogen sulfide from its respective elements wherein sulfur and hydrogen are reacted in a diffusion flame in a temperature range of 650.degree. to 1300.degree. C.

Abstract: Sulfur oxides are removed from gases by contact with a composition containing potassium and cerium on alumina, the cerium being present in the form of crystals of oxide of crystal size below about 90 Angstrom Units.

Abstract: A process is provided in which particulates and sulfur oxides are simultaneously removed from flue gases in a granular bed filter and scrubber with copper-containing adsorbers at special adsorption temperatures. The spent adsorbers can be thermally regenerated in a lift pipe riser, at particular regeneration temperatures.

Abstract: A process is provided in which particulates, nitrogen oxides, and sulfur oxides are simultaneously removed from flue gases in a granular bed filter and scrubber with a nitrogen oxide-capturing reducing agent and a bed of sulfur oxide-capturing and particulate-removing material. The spent sulfur oxide-capturing and particulate-removing material can be regenerated in a lift pipe riser.

Abstract: A process is provided in which particulates and sulfur oxides are simultaneously removed from flue gases in a granular bed filter and scrubber with special sulfur oxide-capturing and particulate-removing material. The spent sulfur oxide-capturing and particulate-removing material can be regenerated in a lift pipe riser.

Abstract: Sulfur oxides are removed from gases by contact with a composition containing 3 w % potassium and 3 w % cerium or alumina.

Abstract: Certain impure steams, especially those from geothermal sources, are contaminated with gaseous substances such as hydrogen sulfide, ammomia, carbon dioxide, substances comprising boron, arsenic and mercury, other gases, as well as finely divided particulate solid matter in a form resembling dust or smoke. These contaminants reduce the efficiency of the steam as a heat transfer fluid and are detrimental to equipment utilizing steam as an energy source. Furthermore, discharges from the utilization of such impure steams result in pollution of the environment or necessitate expensive requirements for limiting the same. The present invention describes apparatus wherein so contaminated steam is selectively processed at superatmospheric pressure for removing one or more of said contaminants and, after reduction of its energy content by pressure reduction and/or condensation of the steam, gases substantially free of hydrogen sulfide are discharged to the atmosphere.

Abstract: This invention is a regenerable process for producing gaseous hydrogen sulfide in concentrated form from sulfur dioxide obtained from a dilute gas source by (1) reacting the SO.sub.2 with a concentrated solution of Na.sub.2 SO.sub.3 to form Na.sub.2 S.sub.2 O.sub.5 in solution and then either: (2) reacting the Na.sub.2 S.sub.2 O.sub.5 with Na.sub.2 CO.sub.3 to form solid Na.sub.2 SO.sub.3, a concentrated solution of Na.sub.2 SO.sub.3 which is recycled to the SO.sub.2 reaction and concentrated gaseous CO.sub.3 which is used in a subsequent step, (3) reducing the Na.sub.2 SO.sub.3 to Na.sub.2 S, (4) reacting the Na.sub.2 S with solid NaHCO.sub.3 to form gaseous H.sub.2 S and Na.sub.2 CO.sub.3, (5) recycling part of the Na.sub.2 CO.sub.3 to (2) above and reacting the remainder with concentrated CO.sub.2 from (2) above to form solid NaHCO.sub.3 and recycling the solid NaHCO.sub.3 to (4) above, or; (2) reacting the Na.sub.2 S.sub.2 O.sub.5 with NaHCO.sub.3 to form solid Na.sub.2 SO.sub.

Abstract: A process is set forth for the selective removal of acid gases such as H.sub.2 S, COS and CO.sub.2 from a gas stream by contacting the stream with a bis tertiary amino alkyl solvent compound such as 4,4'-(oxydi-2,1-ethanediyl) bismorpholine. When used in an aqueous solution, the compounds catalytically hydrolyze COS to H.sub.2 S and CO.sub.2.

Abstract: Process and composition for removing H.sub.2 S and like sulfides from gas streams by contact with a substituted aromatic nitrile having an electron-attracting substituent on the aromatic ring at least as strong as halogen (e.g., isophthalonitrile) and an organic tertiary amine in an inert organic solvent such as N-methyl-2-pyrrolidone.

Abstract: Sulfur species are removed from a Claus plant tail gas stream by contacting with zinc oxide in the presence of sufficient reducing equivalents for conversion of sulfur compounds to hydrogen sulfide. In another aspect, sulfur compounds are converted to hydrogen sulfide prior to contacting with zinc oxide.