Abstract: Sulfur is produced by contacting, in a catalytic selective oxidation zone, a feed gas comprising an acid gas stream containing hydrogen sulfide in admixture with about 70 to 130 percent of the stoichiometric amount of oxygen required for conversion of hydrogen sulfide to sulfur and a recycle gas which is a portion of the gas resulting from condensing sulfur from the effluent of the catalytic selective oxidation zone with a catalyst selectively capable of oxidizing hydrogen sulfide to sulfur dioxide substantially without formation of sulfur trioxide to form a gas stream comprising hydrogen sulfide, sulfur dioxide and sulfur at a temperature between the kindling temperature of the catalyst and about 850.degree. F. Formed sulfur is condensed from the effluent gas stream and a portion of the substantially sulfur-free effluent returned as recycle gas.

Abstract: In a process of decreasing the sulfur content of exhaust gases obtained during the recovery of sulfur from acid gases containing H.sub.2 S and other S-containing compounds in the Claus process, the acid gases which contain H.sub.2 S and other S-containing compounds are reacted in a Claus plant to form elemental sulfur. A gas which contains H.sub.2 S or SO.sub.2 is subsequently added at a controlled rate to maintain a stoichiometric ratio of 2:1 of H.sub.2 S to SO.sub.2 in the tail gas from the Claus plant. The gas which contains H.sub.2 S or SO.sub.2 may be added to the tail gas from the Claus plant or before the last contacting stage of a multistage Claus plant. During the addition of a gas which contains H.sub.2 S, the Claus plant can be operated at an H.sub.2 S to SO.sub.2 ratio of or below 2:1. During the addition of a gas which contains SO.sub.2 the Claus plant can be operated at an H.sub.2 S to SO.sub.2 ratio of or above 2:1. The H.sub.2 S and SO.sub.

Abstract: An apparatus and process are provided for recovering and utilizing heat emanating from the shell of a thermal reactor in a sulfur recovery plant. Air is allowed to pass between the metal shell of a thermal reactor and an insulating jacket that partially encloses the shell. As the air exits through an opening at the top of the insulating jacket it is collected by a collection hood located above the thermal reactor. The collected air is then forced into the inlet of the thermal reactor where it is mixed with acid gas and thereby the heat emanating from the thermal reactor is recirculated to heat the reaction zone.

Abstract: Ammonium compounds deposited on catalyst in a sulfur recovery facility are removed by passing a hot regeneration stream in contact with the catalyst to produce a regeneration effluent stream containing ammonia followed by combustion or catalysis to reduce the concentration of ammonia in the regeneration effluent stream.

Abstract: Shaped titanium oxide catalysts/carriers useful, e.g., for sulfur recovery via Claus catalysis, are prepared by (i) intimately admixing powdered, poorly crystalline and/or amorphous titanium oxide, said titanium oxide powder being characterized by a weight loss on ignition ranging from 1 to 50%, water and from 0 to about 15% by weight of a shaping additive, (ii) next shaping the intimate admixture which results, and (iii) thence, optionally after drying, calcining the product shaped article.

Abstract: Hydrogen sulfide is selectively oxidized in a gas stream containing at least 20 mol percent a carbon dioxide using an iron catalyst, preferably Fe.sub.2 O.sub.3 supported on a ceramic honeycomb support.

Abstract: A process for removing hydrogen sulphide and sulphur dioxide from a Claus reaction tail gas comprises separating the tail gas into two partial streams, conducting the first partial stream through a first catalyst bed charged with sulphur while at a temperature above the sulphur dew point, separating out the discharged sulphur from the first partial stream by condensation, combining the first partial stream freed from sulphur with the second partial stream, and passing the combined gas stream through a second catalyst bed already freed from sulphur while at a temperature below the sulphur dew point. When the second catalyst bed becomes charged with sulphur and the first catalyst bed becomes free of sulphur, the flow of gas through the beds is reversed.

Abstract: Reactive gases containing sulfur dioxide and hydrogen sulfide, e.g. reaction gases of the CLAUS process, are passed through a catalyst stage having an inlet side and an outlet side for the gas mixture to produce elemental sulfur and water in accordance with the reaction2H.sub.2 S+SO.sub.2 .fwdarw.3S+2H.sub.2 O+Qwhere Q is the heat liberated in this exothermic reaction. According to the invention the gases are cooled between the inlet and discharge sides by heat-exchanger means to a temperature not less than the activation temperature for the reaction and preferably not less than the temperature at which the gases are initially introduced into the catalyst body. The heat exchanger means can be provided in gaps between catalyst beds and/or within the catalyst beds of the body of catalyst.

Abstract: A process is provided for producing elemental sulphur from a hydrogen sulphide and sulphur dioxide containing gas stream by a Claus type of catalytic reaction. The process is based on the discovery that the conventional Claus catalyst, in the presence of liquid sulphur and at pressures considerably greater than one atmosphere, is significantly active toward the Claus catalytic reaction. Thus, in accordance with the invention, increasing the pressure of the reaction in the presence of liquid sulphur increases both the catalytic activity and the elemental sulphur conversion. The process involves introducing a compressed hydrogen sulphide and sulphur dioxide containing gas stream into a catalytic reactor and reacting the gases in a Claus catalyst bed in the reactor to produce elemental sulphur under conditions of temperature and pressure such that water in the reactor exists only as water vapor and sulphur vapor is condensed in the catalyst bed, being removed therefrom as a liquid.

Abstract: Sulfur is produced by contacting, in a catalytic selective oxidation zone, a feed gas comprising an acid gas stream containing from about 1 to 100 percent by volume in admixture with about 70 to 130 percent of the stoichiometric amount of oxygen required for conversion of hydrogen sulfide to sulfur and a recycle gas which is a portion of the gas resulting from condensing sulfur from the effluent of the catalytic selective oxidation zone, with a catalyst selectively capable of oxidizing hydrogen sulfide to sulfur dioxide substantially without formation of sulfur trioxide to form a gas stream comprising hydrogen sulfide, sulfur dioxide and sulfur at a temperature between the kindling temperature of the catalyst and about 850.degree. F. Formed sulfur is condensed from the effluent gas stream and a portion of the substantially sulfur-free effluent returned as recycle gas.

Abstract: In a process for eliminating impurities and undesirable components from gas mixtures by passing the mixture through an activated carbon-containing adsorber. Sulfur compounds including hydrogen sulfide are eliminated by increasing the oxygen contents of the gas mixture which contains at least oxygen and/or sulfur dioxide in addition to the hydrogen sulfide to an extent that a hydrogen sulfide oxygen molar ratio is obtained in the gas mixture which is between about 1:0.45 and 1:0.65. The process may also be carried out with two groups of adsorbers where in the first adsorber the elemental sulfur is eliminated in liquid form and where the remaining minor portion of sulfur in vaporous or mist-like form is then removed in the second group of adsorber or adsorbers by adsorption on the activated coal. The purified gas is then recovered from the adsorber or with two groups of adsorbers from the second group of adsorber or adsorbers and the activated carbon is subjected to periodic regeneration cycles.

Abstract: A process is disclosed for removing and recovering from gas streams the sulfur values of dilute concentrations of sulfur vapor, hydrogen sulfide, and sulfur dioxide which are not recoverable by previously known methods. The gas streams are scrubbed with aqueous suspensions of solid catalytic material which precludes formation of collodial sulfur in the aqueous suspension and collects the sulfur values as solid sulfur deposit, which is recovered during restoration of catalytic activity of the solid catalytic material.

Abstract: The Claus process for the production of sulphur is improved by employing a deoxidation catalyst prior to the conventional Claus oxide catalyst.

Abstract: Poisoned alunina catalyst is removed from the reactor and washed with hot water to remove soluble sulfates. The carbon on the washed catalyst is then burned off and the product may again be washed to remove further sulfates formed during the oxidative burn-off. The activity of the catalyst thus regenerated is comparable to that of fresh alumina catalyst employed for sulfur recovery by the modified Claus process.

Abstract: An improved method of regenerating a low temperature Claus catalyst bed having elemental sulfur deposited on the catalyst involving initially using a moderately hot effluent gas (typically 600.degree. to 650.degree. F.) from the first conventional Claus reactor to warm up the low temperature Claus reactor and remove deposited sulfur and after the outlet temperature of said low temperature reactor reaches a value high enough to decompose COS and CS.sub.2 (typically 600.degree. to 650.degree. F.), supplementing the moderately hot first conventional Claus reactor effluent gas with hot (typically 1000.degree. to 1200.degree. F.) waste heat boiler effluent such that the temperature of the regenerating catalyst bed can be elevated to about 700.degree. F. or higher. The intentional temperature excursion to about 700.degree. F. during catalyst regeneration improves the degree of regeneration of the catalyst bed, promotes higher catalyst activity and extends the catalyst life.

Abstract: The invention concerns catalysts for treating residual gases, containing hydrogen and carbon derivatives of sulphur, by the Claus reaction. These catalysts have a specific area of at least 80 m.sup.2 /g and essentially comprise active alumina and a titanium compound. They enable carbon compounds of sulphur to be destroyed and the Claus reaction proper to be obtained with good yields.

Abstract: A process for recovering sulfur from sour gas, and providing valuable byproducts, the sour gas consisting principally of hydrogen sulfide and carbon dioxide, and the process consisting of the steps of combusting a portion of the hydrogen sulfide with pure oxygen to produce a mixture of H.sub.2 S and SO.sub.2, reacting the mixture successively over a series of catalytic converter beds wherein they react to produce water and elemental sulfur, the elemental sulfur being condensed after each converter, and the gaseous output of each converter being repressurized and reheated before entering the next successive converter to improve the yield of sulfur therein, combusting the gaseous output of the final converter of the series with pure oxygen in a final catalytic converter to convert any remaining H.sub.2 S to SO.sub.2, and treating the H.sub.2 O, SO.sub.2 and CO.sub.2 mixture emerging from said converter to remove therefrom the water and CO.sub.2, which are in themselves valuable byproducts and recycling the SO.

Abstract: An improved method for reducing the sulfur losses associated with leakage across closed valves in a Claus type sulfur recovery plant involving the recirculating of low sulfur content Claus tail gas to the high pressure side of the closed valves. This improved method for compensating for leakage across a closed valve is particularly useful in sealing a valve in the so-called Cold Bed Adsorption plant. Thus, allowing a conventional carbon steel valve of an undercut design to be used at a temperature range from under 250.degree. F to over 650.degree. F while meeting contemporary emission standards.

Abstract: In the Claus process wherein hydrogen sulfide and sulfur dioxide are reacted to form sulfur and a waste exhaust gas, the invention treats the exhaust gas to recover additional sulfur therefrom.

Abstract: Integrating an absorption-desorption step, a Claus plant, and a catalytic hydrogen reactor in a recycle loop provides a gas-desulfuration plant that operates at a substantially zero emission level. Hydrogen sulfide is removed from industrial gas streams by absorption-desorption in a liquid absorbent. The resulting foul gas is then reacted with sulfur dioxide in a Claus reaction, i.e., the reaction of hydrogen sulfide with sulfur dioxide to form elemental sulfur and water. The tail gas from this Claus reaction is then passed through a catalytic hydrogenation reactor together with a supply of hydrogen to reduce the sulfur and sulfur compounds to hydrogen sulfide. The now reduced tail gas is then recycled back to the industrial gas, upstream of the absorption-desorption step.

Abstract: A process is provided for preparing catalytically active emerald green colored alumina by contacting colorless alumina with carbonyl sulfide. This material catalyzes the reduction of sulfur dioxide by carbon monoxide.

Abstract: Catalysts for Claus reaction treatment of industrial gases containing hydrogen sulphide and sulphur dioxide in which the catalyst has a specific surface area of at least 80 sq.m./g and is composed of activated alumina and a compound of a metal of column III A of the periodic classification of elements which is present, when calculated as the oxide, in an amount within the range of 1-20% by weight of the catalyst.

Abstract: Process for purifying a gas containing hydrogen sulfide and sulfur dioxide, comprising substantially removing sulfur dioxide, absorbing hydrogen sulfide on a solid contact mass, intermittently regenerating said mass by means of an oxygen-containing gas, so as to produce a gas containing sulfur dioxide, and reacting the latter gas with hydrogen sulfide to produce 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: Sulfur dioxide is reduced to sulfur and hydrogen sulfide with a gaseous reducing agent in the presence of a catalyst by a process involving mixing a sulfur dioxide-containing gas stream with a portion of the gaseous reducing agent and passing the resulting mixture through a first reactor to effect reduction of a portion of the sulfur dioxide to hydrogen sulfide and sulfur, mixing the gas stream from the first reactor with the remaining gaseous reducing agent, and splitting the resulting mixture into two gas streams which are in parallel passed through a second and third reactor to effect reduction of sulfur dioxide to form hydrogen sulfide and sulfur. Periodically, the flow in the first and third reactors is reversed to thereby subject these reactors to periodically alternating heat absorbing and desorbing cycles while the flow in the second reactor is always maintained in the same direction.

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: An improved method for further removal of sulfur from the tail gas of a conventional Claus plant by the use of a Cold Bed Adsorption process involving the specific improvement of maintaining at all times the lead Claus reactor of a series of such reactors at sufficiently high temperatures to promote hydrolysis of COS and CS.sub.2 and then utilizing part or all of the hot effluent gases of this lead reactor to regenerate the sulfur-fouled Cold Bed Adsorption catalyst by passing the hot stream through the fouled reactor, removing the deposited sulfur and then returning the stream to the Claus plant at a point essentially immediately downstream from where it was originally withdrawn. Such a method is useful in maintaining ultra-high sulfur conversion levels on a commercial scale.

Abstract: Catalysts for Claus reaction treatment of industrial gases containing hydrogen sulphide and sulphur dioxide in which the catalyst has a specific surface area of at least 80 sq.m./g and is composed of activated alumina and a compound of lanthanum, a lanthanide series metal of atomic number 58 to 71 or a metal of Group IIIB of the periodic classification of elements which is present, when calculated as the oxide, in an amount within the range of 1-20% by weight of the catalyst.

Abstract: Certain zeolite materials have been found to be effective zeolite adsorbents-catalysts for the adsorption and conversion of sulfuric compounds to elemental sulfur. These zeolites adsorb hydrogen sulfide and sulfur oxides and promote the reaction of these materials so as to produce sulfur. These useful zeolites are the hydrogen forms of the zeolite materials and sodium exchanged hydrogen zeolites, especially mordenite. These zeolite adsorbents-catalysts are very useful for the removal of small amounts of hydrogen sulfide and sulfurous oxide from effluent streams such as effluent streams from Claus reactors.

Abstract: This invention is addressed to a method of catalytic treatment of residual gases containing various compounds of sulphur, particularly hydrolyzable compounds of sulphur by the Claus reaction.These residual gases, at the expense of which all or part of the necessary amount of sulphurous anhydride is formed, are treated at temperatures above 200.degree.C in the presence of catalysts comprising active alumina and one or more oxides, sulphides or compounds capable of being sulphurized, of molybdenum, cobalt, nickel, iron and uranium.