Abstract: The application relates to a process for the removal of hydrogen sulfide from a gas stream by catalytic direct oxidation without employing the combustion step of a Claus process. The process is particularly suitable for desulfurization of gas streams that contain hydrogen and allows sulfur recovery efficiency of better than 99%.

Abstract: Processes for the thermal reduction of sulfur dioxide to elemental sulfur in a single reaction furnace are disclosed. The reaction furnace contains an alumina monolith that performs as an active catalyst. The reaction furnace is followed by a Claus conversion zone, wherein H2S and SO2 react to produce additional elemental sulfur. Three methods to eliminate soot formation and two methods to consume produced H2 and CO are described. One or combination of these methods may be employed which consists of a) adding steam (water vapor), b) adding recycled sulfur or c) adding recycled tail gas.

Abstract: A method for removing sulfur-containing compounds is provided. In one embodiment, the method includes selectively separating a feed stream (118) comprising carbon dioxide and one or more sulfur-containing compounds, including hydrogen sulfide, at conditions sufficient to produce a first stream (122) comprising carbon dioxide and hydrogen sulfide and a second stream (124) comprising carbon dioxide and hydrogen sulfide. A molar ratio of carbon dioxide to hydrogen sulfide in the first stream is greater than a molar ratio of carbon dioxide to hydrogen sulfide in the second stream, and a molar ratio of hydrogen sulfide in the first stream to hydrogen sulfide in the second stream is about 0.005 or more.

Abstract: A process for obtaining energy values contained in a sulphur-containing carbonaceous fuel, the process comprising (a) treating a feed carbonaceous fuel having a first bound-sulphur content with an effective amount of an oxygen and SO2-containing gas in a reactor at an effective temperature to (i) provide elemental sulphur from the SO2, (ii) release exothermic heat, and (iii) produce a hot effluent gaseous steam containing the elemental sulphur and treated fuel having a second bound-sulphur content, (b) separating the elemental sulphur from the treated fuel; (c) collecting the elemental sulphur; (d) collecting the treated fuel; and (e) collecting the exothermic heat.

Abstract: Apparatus and process for recovering elemental sulfur from a H2S-containing waste gas stream are disclosed. The apparatus preferably comprises a first reaction zone for carrying out the catalytic partial oxidation of H2S, a second reaction zone for the catalytic partial reduction of any incidental SO2 produced in the first reaction zone, and a cooling zone including a sulfur condenser. According to a preferred embodiment of the process, a mixture of H2S and O2 contacts a catalyst in the first reaction zone very briefly (i.e, less than about 200 milliseconds) producing primarily S0 and H2O. Some SO2 is also present in the first stage product gas mixture. A reductant gas (e.g. CO, or CH4 or natural gas) is fed together with the first stage product gas mixture to a second catalytic reaction zone where the partial reduction of the SO2 component to elemental sulfur and CO2 is carried out.

Abstract: A gas refining method for adsorbing a reducing gas obtained by pressure gasification of coal or oil comprises introducing a reducing gas stream into an adsorbing and removing zone where it contacts an adsorbent. Sulfur-containing compounds are adsorbed onto the adsorbent and a first oxygen-containing gas stream is introduced into the adsorbing and removing zone in order to form a regeneration gas containing sulfur dioxide. The regeneration gas is contacted with a second oxygen-containing stream and a calcium-containing liquid slurry to effect absorption of sulfur dioxide by the slurry and precipitation of a gypsum compound. The temperature of the slurry is varied to cause selective precipitation of 60 -gypsum hemihydrate or gypsum dihydrate.

Abstract: A method is provided for removal of sulfur gases and recovery of elemental sulfur from sulfur gas containing supply streams, such as syngas or coal gas, by contacting the supply stream with a catalyst, that is either an activated carbon or an oxide based catalyst, and an oxidant, such as sulfur dioxide, in a reaction medium such as molten sulfur, to convert the sulfur gases in the supply stream to elemental sulfur, and recovering the elemental sulfur by separation from the reaction medium.

Abstract: The present invention is a process wherein a process gas comprising at least SO2 and H2S is reacted across a stage of SO2 reducing catalyst, thereby obtaining high conversion of at least the SO2 to elemental sulfur.

Abstract: This invention relates to a gas refining system wherein a high-temperature and high-pressure reducing gas is introduced into a fixed-bed desulfurizer packed with an adsorbent by which sulfur compounds contained in the high-temperature and high-pressure reducing gas are adsorbed and removed in the form of a sulfide, and the adsorbent having the sulfide adsorbed thereon is regenerated by roasting it with a regenerating gas containing oxygen, characterized in that the gas refining system is equipped with oxygen concentration control means for controlling the oxygen concentration in the regenerating gas introduced into the desulfurizer so as to keep the internal temperature of the desulfurizer during the regeneration reaction within the allowable temperature range of the adsorbent.

Abstract: The invention relates to an all-metal catalyst for the oxidation of gaseous sulphur compounds, more particularly hydrogen sulphide, in an oxygen-containing atmosphere, said catalyst consisting of a metal alloy of 5 to 70% by weight nickel and 30 to 95% by weight copper as residue thermally treated at temperatures of 400.degree. to 1000.degree. C. in an oxygen-containing atmosphere for 0.25 to 5 hours.

Abstract: The present invention discloses a method for the catalytic reduction of sulfur dioxide, for example in flue gas, by carbon monoxide using lanthanum oxysulfide as the active catalyst. The catalyst is prepared from lanthanum oxide by hydration and sulfidization, the latter step being carried out in the gas stream itself. This method of preparation has more general applicability and can also be used as a method for the preparation of lanthanum, yttrium, gadolinium and lutetium oxysulfides generally.

Abstract: A method for producing elemental sulfur and reduced/oxidized sulfur compounds from sulfur containing gases. The method comprises mixing a primary gas stream of sulfur-containing gases with a secondary gas stream to produce a combined gas stream having a preselected stoichiometry and contacting the combined gas stream with a catalyst at a pressure of 7 to 100 atmospheres and a temperature of 540.degree. to 700.degree. C. The catalyst is selected from the group consisting of silica, titania, alumina, sodium/alumina, zinc titanate, alumina or titania promoted with transition metals nickel, cobalt, molybdenum, tungsten, alloys and mixtures thereof and mixture of such catalysts.

Abstract: Cement and elemental sulfur are produced by forming a moist mixture of a flue gas desulfurization process waste product containing 80-95 percent by weight calcium sulfate hemihydrate and 5-20 percent by weight calcium sulfate hemihydrate, aluminum, iron, silica and carbon, agglomerating the moist mixture while drying the same to form a feedstock, and calcining the dry agglomerated feedstock in a rotary kiln. Sulfur dioxide produced during the calcination is cooled and contacted with hydrogen and carbon monoxide to reduce the same to elemental sulfur.

Abstract: The inventive catalysts allow for the reduction of sulfur dioxide to elemental sulfur in smokestack scrubber environments. The catalysts have a very high sulfur yield of over 90% and space velocity of 10,000 h.sup.-1. They also have the capacity to convert waste gases generated during the initial conversion into elemental sulfur. The catalysts have inexpensive components, and are inexpensive to produce. The net impact of the invention is to make this technology practically available to industrial applications.

Abstract: Disclosed are, in a method for purifying a high-temperature reducing gas in which sulfur compounds present in a high-temperature reducing gas are absorbed and removed by an absorbent according to a dry method, a method for purifying a high-temperature reducing gas which is characterized in that a reducing gas is supplied into a gas containing sulfur dioxide gas which is discharged from a regeneration system for regenerating the absorbent which system forms a system together with an absorption system in which the sulfur compounds are absorbed with the absorbent, a resulting gas mixture is led through a reactor filled with a catalyst, the sulfur dioxide gas and the reducing gas are let react with each other under pressurization so that elemental sulfur is directly produced and recovered as liquid sulfur; and the above method which is further characterized in that catalyst layers in the reactor in which the sulfur dioxide gas and the reducing gas react with each other are divided into parts or made to have a plu

Abstract: A method for producing elemental sulfur and reduced/oxidized sulfur compounds from sulfur containing gases. The method comprises mixing a primary gas stream of sulfur-containing gases with a secondary gas stream to produce a combined gas stream having a preselected stoichiometry and contacting the combined gas stream with a sorbent/catalyst. The sorbent/catalyst is selected form the group consisting of silica, alumina, and other Claus-type catalysts, sodium/alumina, zinc ferrite, zinc titanate, and other mixed metal oxides, and mixtures thereof.

Abstract: An improved catalytic reduction process for the direct recovery of elemental sulfur from various SO.sub.2 -containing industrial gas streams. The catalytic process provides combined high activity and selectivity for the reduction of SO.sub.2 to elemental sulfur product with carbon monoxide or other reducing gases. The reaction of sulfur dioxide and reducing gas takes place over certain catalyst formulations based on cerium oxide. The process is a single-stage, catalytic sulfur recovery process in conjunction with regenerators, such as those used in dry, regenerative flue gas desulfurization or other processes, involving direct reduction of the SO.sub.2 in the regenerator off gas stream to elemental sulfur in the presence of a catalyst.

Abstract: Novel catalysts for the purification of gaseous effluents containing contaminating amounts of sulfur compounds include a catalytically active phase for the oxidation of such sulfur compounds into elemental sulfur, SO.sub.2 and/or SO.sub.3 and are shaped as to have a ratio between their external surface area and their volume of at least 2 mm.sup.-1 ; advantageously such catalysts have a concave multilobal configuration, preferably trilobal or quadrilobal.

Abstract: Novel sorbents comprising (a) an alumina substrate having a pore volume between 0.4 and 0.8 cc/g, and (b) an alkali or alkaline earth component, for example, sodium carbonate, wherein the amount of the alkali or alkaline earth component is between 50 and 400 .mu.g per m.sup.2 of the substrate. The sorbents of the present invention are outstandingly effective for the removal of nitrogen oxides, sulfur oxides and hydrogen sulfide from waste gas streams.

Abstract: A combination gas denitrogenation and desulfurization process is provided in which a gaseous mixture comprising NO.sub.x, SO.sub.x and O.sub.2 is reacted with excess NH.sub.3 to reduce the NO.sub.x to N.sub.2 and the resulting gaseous effluent comprising the unreacted ammonia and SO.sub.x is passed to a gas desulfurization zone to form an ammonium salt of an acid of sulfur which can be recovered and used as such or converted to elemental sulfur.

Abstract: Sulphur is manufactured out of sulphur dioxide containing gases by dividing the feed gas in two flows of gas having a volume ratio of 2 to 1 and reducing the greater flow of gas on a carbon containing substance like anthracite, thereby obtaining hydrogen sulfide which is mixed with the smaller flow of gas, the mixture being converted in a Claus process to sulphur.

Abstract: An improved method for the recovery of elemental sulfur(S) from a coal-gas containing hydrogen sulfide (H.sub.2 S) wherein hot lime (CaO) is used and then regenerated according to the following chemistry:CaO+H.sub.2 S=CaS+H.sub.2 OCaS+3/2 O.sub.2 =CaO+SO.sub.2SO.sub.2 +C=S+CO.sub.2These chemical reactions are conducted in-situ while the supply of carbon (C) for the formation of the elemental sulfur(S) is derived from a component of the coal-gas itself to increase the overall efficiency of desulfurization, increase the uniformity of the carbon deposit into the hot lime (CaO), and eliminate the extra and cumbersome steps of physically moving the spent lime (CaO) for regeneration and returning it after regeneration, and the step of adding coal to react with the sulfur dioxide (SO.sub.2) formed as an off-gas during regeneration.

Abstract: A process for production of sulfur from SO.sub.2 -containing gas is disclosed comprising the steps of contacting said SO.sub.2 -containing gas mixed with additional oxygen or air, with carbonaceous materials, in a SO.sub.2 reduction reactor under elevated temperatures to thereby produce a first gaseous mixture containing vaporous sulfur, H.sub.2 S, COS and unreacted SO.sub.2 ; separating said vaporous sulfur by condensation from the first gaseous mixture to thereby obtain a second gaseous mixture; introducing the second gaseous mixture into a Claus reactor to thereby obtain a third gaseous mixture containing a vaporous sulfur produced by Claus reaction; separating said vaporous sulfur by condensation from the third gaseous mixture to thereby obtain a fourth gaseous mixture of reduced sulfur compound content; and recovering the sulfur separated from said first and third gaseous mixtures, the improvement comprising regulating the amount of oxygen or air mixed with the SO.sub.

Abstract: SO.sub.2 -containing gas is made to contact a carbon-containing material to reduce the gas to a gas mixture containing sulfur and also containing H.sub.2 S and SO.sub.2 in a volume ratio of 2:1. The sulfur is then removed by condensation and the remaining gas mixture subjected to a Claus-process treatment to obtain additional sulfur from it.

Abstract: Sulfur dioxide is converted to elemental surfur by reduction with a carbonaceous material in a reaction zone containing a molten salt. Heat is provided by reacting a portion of the carbonaceous material with oxygen. In a preferred embodiment alkali metal sulfates present in the molten salt are reduced to alkali metal sulfides.

Abstract: A multi-stage process for reducing the content of sulfur-containing gases--notably hydrogen sulfide, sulfur dioxide, carbonyl sulfide and carbon disulfide--in waste gas streams is provided. In the first stage, the gas stream is passed through a reaction zone at a temperature between about 150.degree. and 350.degree. C. in the presence of a pretreated novel catalyst of the formulaxLn.sub.2 O.sub.3.yT.sub.2 O.sub.3in which Ln is yttrium or a rare earth element and T is cobalt, iron or nickel, and each of x and y is independently a number from 0 to 3, said catalyst being substantially non-crystalline and having a surface area of from about 10 m.sup.2 /g to about 40 m.sup.2 /g. The preferred catalyst is one in which Ln is lanthanum, T is cobalt, and x and y range from 1 to 3, including non-integers. The first stage yields a product stream having a reduced content of sulfur-containing gases, including specifically, substantial reduction of carbonyl sulfide and virtual elimination of carbon disulfide.

Abstract: A system for reducing sulfur dioxide in which a vessel is provided with an inlet for receiving coal and a plurality of gas distribution nozzles for receiving the sulfur dioxide and discharging same downwardly in the lower portion of the vessel for flowing upwardly in a counterflow relation to the coal. The coal flows through a distribution device located in the hopper section of the vessel for insuring an even distribution of coal through the vessel.

Abstract: A waste gas containing sulfur oxides is contacted with an adsorbent comprising an intimate mixture of an iron oxide and/or a copper oxide and a titanium oxide at a temperature of 250.degree.-500.degree. C. The sulfur oxides thus adsorbed are desorbed with a reducing gas and recovered as sulfur material.The efficiency of the adsorbent is not reduced even after many repetitions of the adsorption-desorption cycle. Since the adsorbent exhibits a high resistance to sulfuric acid mist (SO.sub.3) contained in the waste gas.

Abstract: This invention relates to a process for the prevention of carbonaceous deposits from forming on the surfaces of catalytic materials employed in the reduction of sulfur dioxide in a gas stream with a gaseous reductant to produce elemental sulfur by a process consisting essentially of preheating separately the sulfur dioxide gas stream to a temperature above the initiation temperature of the reduction reaction and the gaseous reductant stream to a temperature below the initiation temperature of the reduction reaction, preferably mixed with elemental sulfur vapor, rapidly mixing the two preheated streams just prior to their introduction into a reaction zone, passing the resulting mixture through the reaction zone under reaction conditions, including an initiation temperature, sufficient to effect reaction of said gaseous reductant with the sulfur dioxide and recovering a product stream containing elemental sulfur.

Abstract: A catalytic process for the reduction to elemental sulfur of the sulfur dioxide contained in gas streams using a reducing gas such as hydrogen, or preferably carbon monoxide, in a reactor charged with a material represented by the general formula M.sup.II M.sub.2.sup. III O.sub.4 crystallized in the spinel structure wherein M.sup.II is a divalent metal and M.sup.III is a trivalent metal from the first transition period of the Periodic Table of the Elements, or derivatives of the materials of the above formula resulting from pretreatment with hydrogen or, preferably carbon monoxide, and/or exposure to the sulfur dioxide-containing gas stream.

Abstract: A process for the recovery of carbon disulfide from a flue gas. A stream of sulfur dioxide is removed from a flue gas and introduced into a first reduction reactor containing a chromium promoted iron oxide catalyst where the sulfur dioxide is reduced to carbonyl sulfide. The carbonyl sulfide is introduced into a second reduction reactor which contains an active alumina catalyst. The carbonyl sulfide decomposes to carbon disulfide which is recovered.

Abstract: A process for the cyclic removal of sulphur oxides from gases in which the regeneration offgas containing sulphur oxides is partially combusted to produce a reducing gas and elemental sulphur.

Abstract: A process for the oxidation of carbon monoxide to carbon dioxide with an inorganic oxidizing agent selected from the group consisting of water, nitric oxide and sulfur dioxide, which comprises combining the carbon monoxide with a predetermined amount of said oxidizing agent to give at least a stoichiometric amount of the oxidizing agent for the oxidation of the carbon monoxide to carbon dioxide, and passing the mixture over a novel ceramic catalyst at an elevated temperature.

Abstract: A process for recovering elemental sulfur from gases containing inorganic and/or organic sulfur compounds together with large quantities of carbon dioxide and other possible impurities such as unsaturated hydrocarbon and hydrogen cyanide. The waste gas is combined with a combustion-promoting gas and the resulting mixture is burned with a slight excess of air and caused to contact coke at a temperature of 300.degree. to 450.degree. C. The resulting gas, from which oxygen, sulfur trioxide and nitrogen oxide have been removed, by contact with the coke, is cooled to 20.degree. to 80.degree. C and then is scrubbed with aqueous alkali salts of weak inorganic and/or organic acids or amines to remove SO.sub.2. The absorbent is stripped and the recovered SO.sub.2 is reacted with hydrogen at 200.degree. to 400.degree. C to form sulfur and/or hydrogen sulfide and, when hydrogen sulfide is produced, the latter is reacted on alumina or activated carbon at 200.degree. to 300.degree. C to produce the elemental sulfur.

Abstract: A continuous catalytic fused salt extraction process is described for removing sulfur oxides from gaseous streams. The gaseous stream is contacted with a molten potassium sulfate salt mixture having a dissolved catalyst to oxidize sulfur dioxide to sulfur trioxide and molten potassium normal sulfate to solvate the sulfur trioxide to remove the sulfur trioxide from the gaseous stream. A portion of the sulfur trioxide loaded salt mixture is then dissociated to produce sulfur trioxide gas and thereby regenerate potassium normal sulfate. The evolved sulfur trioxide is reacted with hydrogen sulfide as in a Claus reactor to produce elemental sulfur. The process may be advantageously used to clean waste stack gas from industrial plants, such as copper smelters, where a supply of hydrogen sulfide is readily available.

Abstract: A SO.sub.2 -containing gas is contacted with an ammonia solution, the resulting ammonium sulfite solution is vaporized to SO.sub.2 and NH.sub.3 , SO.sub.2 is partially reduced to H.sub.2 S and the resulting gas containing both SO.sub.2 and H.sub.2 S is first contacted with a catalyst to produce sulfur and then made free of sulfur by solvent washing; recovered NH.sub.3 is used to re-constitute the ammonia solution.

Abstract: A method for reducing sulfur dioxide wherein ammonia is used as the reducing agent. The reduction may be accomplished either thermally or catalytically and the principal products obtained will be elemental sulfur and/or hydrogen sulfide, depending principally upon the particular conditions and relative reactant concentrations actually employed. The sulfur dioxide may be derived from essentially any source. In a preferred embodiment, however, the sulfur dioxide will be derived from a flue gas stream and the same will be separated therefrom with an absorption process wherein ammonia (on an aqueous ammoniacal solution) is also used as the absorbent.

Abstract: Decrepitation of the catalyst occurring in the initial upstream portion of the catalyst bed of the reaction zone in a process for catalytically reducing sulfur dioxide to obtain elemental sulfur is avoided or minimized by employing as the catalyst in at least the initial upstream portion of the bed a supported sulfate of an iron group metal.

Abstract: This application describes a process for the catalytic reduction of sulfur dioxide in gas streams containing sulfur dioxide to elemental sulfur using a reducing gas such as hydrogen or, preferably, carbon monoxide, in a reactor charged with a material represented by the formula Ln.sub.2 O.sub.3 . Co.sub.2 O.sub.3, where Ln is either Y or Gd.In a further aspect of this invention, a gas stream containing hydrogen sulfide or carbonyl sulfide and sulfur dioxide is passed through a reaction chamber charged with Ln.sub.2 O.sub.3 . Co.sub.2 O.sub.3, where Ln is either Y or Gd, to catalytically produce at a sufficiently elevated temperature elemental sulfur with concomitant reduction of the concentrations of the undesired hydrogen sulfide or carbonyl sulfide and sulfur dioxide.

Abstract: The effluent streams from utility stack gases containing nitric oxides and sulfur dioxide are sequentially oxidized, absorbed with effluent spent alkylation acid, the unabsorbed remaining gases contacted with carbon monoxide from alkylation units in refinery cracking and other industrial plants to form sulfur, carbon dioxide and nitrogen, the carbon dioxide and nitrogen being vented, the sulfur oxidized to sulfur trioxide and contacting aqueous sulfuric acid therewith to effect concentration of said acid and suitability for recycle to an alkylation unit; the absorbate containing spent alkylation acid sequentially treated with a burning, oxidation, aqueous dilution and carbon monoxide treatment steps to form sulfuric acid for recycle to an alkylation unit and venting formed carbon dioxide and nitrogen.

Abstract: The effluent streams from utility stack gases containing nitric oxides and sulfur dioxide are entrained with sulfuric acid and carbon monoxide from refinery cracking and other industrial plants and in a sequence of separation and reaction steps nitrogen and carbon dioxide are vented to the atmosphere and regenerated concentrated sulfuric acid and sulfur produced.

Abstract: An improvement on a process for decreasing the total sulfur content of off-gases from a Claus process is described wherein the sulfur dioxide-containing off-gas is mixed with a reducing gas and passed over a metallic reduction catalyst at elevated temperature to reduce the sulfur dioxide and other convertible sulfur compounds present to hydrogen sulfide followed by cooling of the thusly reduced gas stream at least partially by direct cooling with an aqueous quench liquid and removal of the hydrogen sulfide from the cooled gaseous stream by adsorption on an absorbent or absorbent for hydrogen sulfide, in which process the flow of either or both of the sulfur dioxide containing off-gas and the reducing gas to catalytic reduction is controlled by monitoring the sulfur dioxide content of the reduced gas stream.

Abstract: Selective catalysts and processes using same in which SO.sub.x compounds are reduced to elemental sulfur in oxidation-reduction processes in which simultaneously oxidizable gases undergo oxidation.

Abstract: This application describes a process for the catalytic reduction of sulfur dioxide in gas streams containing sulfur dioxide to elemental sulfur using a reducing gas such as hydrogen or, preferably, carbon monoxide, and a catalyst of the formula xLa.sub.2 O.sub.3 . yCo.sub.2 O.sub.3, where x and y are varied independently from 1-3 (including non-integers). Novel catalyst compositions where x .noteq. y are also claimed.

Abstract: This application describes a process for the catalytic reduction of sulfur dioxide in gas streams containing sulfur dioxide to elemental sulfur using a reducing gas such as hydrogen or, preferably, carbon monoxide, and a catalyst of the formula Ln.sub.2 O.sub.3 . Co.sub.2 O.sub.3, where Ln is either Y or Gd.