Abstract: The invention relates to a process for removing hydrogen sulfide and carbon dioxide from a feed gas stream. H2S in the feed gas stream is converted to elemental sulfur in a Claus unit. At least a part of the gas stream obtained is contacted with an aqueous lean absorbing medium in an absorption zone at a pressure between 0.9 and 2 bara. The aqueous lean absorbing medium used comprises one or more amines chosen from: —a polyamine in the absence of tertiary amine functionalities having a pKa sufficient to neutralize carbamic acid, the polyamine having at least one primary amine functionality having a pKa smaller than 10.0 at 25° C., —a polyamine in the absence of tertiary amine functionalities having a pKa sufficient to neutralize carbamic acid, the polyamine having at least one secondary amine functionality having a pKa for each sorbing nitrogen smaller than 10.0 at 25° C. The process is improved as compared to a process involving Claus off-gas treatment with (activated) MDEA.

Abstract: Disclosed herein are scavenging compounds and compositions useful in applications relating to the production, transportation, storage, and separation of crude oil and natural gas. Also disclosed herein are methods of using the compounds and compositions as scavengers, particularly in applications relating to the production, transportation, storage, and separation of crude oil and natural gas.

Abstract: A method to recover sulfur from hydrogen sulfide in an acid gas stream comprising the steps of reacting the hydrogen sulfide and oxygen in the combustion furnace, transferring heat from the furnace effluent to produce a boiler effluent, reducing the temperature of the boiler effluent in the sulfur condenser, separating the water vapor from the non-condensed gases stream, reacting the sulfur dioxide and the hydrogen gas to produce hydrogen sulfide in the first hydrogenation reactor, reacting the hydrogen sulfide and oxygen in the reactor furnace to produce a reactor effluent, transferring heat from the reactor effluent to produce a cooled effluent, reducing the temperature of the cooled effluent in the sulfur cooler to produce a gases stream, separating the water vapor from the gases stream, reacting the sulfur dioxide and the hydrogen gas to produce hydrogen sulfide in the second hydrogenation reactor to produce a treated tail gas stream.

Abstract: The present invention includes a novel salt-free water softening method that utilizes an exchange medium (such as a gel exchange polymer, a macroporous exchange polymer, or an inorganic cation exchanger) that is pre-loaded with a polyvalent cation that has low solubility in aqueous phase at nearly neutral pH. The method of the invention does not require use of a sodium salt or mineral acid in the regeneration of the exchange medium.

Abstract: A system and method for treatment of a medium is disclosed. The system includes a plurality of separator zones and a plurality of heat transfer zones. Each of the separator zone and the heat transfer zone among the plurality of separator zones and heat transfer zones respectively, are disposed alternatively in a flow duct. Further, each separator zone includes an injector device for injecting a sorbent into the corresponding separator zone. Within the corresponding separator zone, the injected sorbent is reacted with a gaseous medium flowing in the flow duct, so as to generate a reacted gaseous medium and a reacted sorbent. Further, each heat transfer zone exchanges heat between the reacted gaseous medium fed from the corresponding separator zone and a heat transfer medium.

Abstract: A system and process for extending turndown in a gas-liquid separator is presented. The system includes a first mist extractor with a first operating range and a second mist extractor with a second operating range. The mist extractors are generally of the same type, with the second operating range being different than the first operating range. A gas stream containing entrained liquid droplets flows through the first mist extractor and then through the second mist extractor. Each mist extractor coalesces and captures the liquid droplets within its own operating range, expanding the overall operating range of the separator. Additional mist extractors may be added to cover any gap between the first and second operating ranges.

Abstract: A process of producing degassed liquid sulfur within a vertical sulfur condenser may include providing a plurality of condenser tubes within an external casing; submerging exit ends of the plurality of condenser tubes within a liquid reservoir resulting in submerged exit ends of the plurality of condenser tubes; passing the Claus process gas into an inlet end of the plurality of condenser tubes; condensing the Claus process gas within the condenser tubes to produce condensed Claus process gas within the plurality of condenser tubes; and collecting the condensed Claus process gas in the liquid reservoir upon exiting of the condensed Claus process gas at an exit end of the plurality of condenser tubes. The process may further include converting hydrogen sulfide by the Claus reaction 2H2S+SO23/xSx+2H2O, and decomposing polysulfanes to hydrogen sulfide and sulfur, wherein elemental sulfur is freed from hydrogen sulfide.

Abstract: The present invention relates to a method for capturing CO2 from exhaust gas in an absorber (A1), wherein the CO2 containing gas is passed through an aqueous absorbent slurry wherein said aqueous absorbent slurry comprises an inorganic alkali carbonate, bicarbonate and at least one of an absorption promoter and a catalyst, and wherein the CO2 is converted to solids by precipitation in the absorber, said slurry having the precipitated solids is conveyed to a separating device (F1), in which the solids are separated off, essentially all of at least one of the absorption promoter and catalyst is recycled together with the remaining aqueous phase to the absorber.

Abstract: A process for removing sulfur compounds, particularly hydrogen sulfide, from a waste gas wherein sulfur dioxide is introduced into the process gas at multiple process locations. Quantities of sulfur dioxide are introduced into the process gas stream at one or more locations preceding catalytic reaction. The process of the present invention may be practiced for Claus processes involving initial thermal reactions, and may be practiced without necessity of preliminary thermal reaction. In an embodiment of the invention, one of the injection locations of sulfur dioxide is the thermal reactor.

Abstract: Configurations herein include a novel process and apparatus for generating and maintaining sulfur trioxide gas. The generation system and process operate to provide sulfur trioxide calibration gas for calibrating sulfur trioxide detection devices. The system and process provides a known, concentration of sulfur trioxide gas via a heated catalyst, which enables accurate calibration of measurement equipment. The system functions in part by controlling temperature, amount of moisture, residence time, catalyst selection, diluting generated sulfur trioxide and by locating the sulfur trioxide generator at a point of injection of a sulfur trioxide detection system.

Abstract: An exhaust gas treating method removes sulfur dioxide from exhaust gas containing at least sulfur dioxide and mercury by bringing the exhaust gas into contact with absorption liquid. Persulfate is added into the absorption liquid or alternatively, iodine gas is added to the exhaust gas before the exhaust gas is brought into contact with the absorption liquid. A high removal rate for both sulfur dioxide and mercury is stably maintained if the load of power generation and the composition of exhaust gas fluctuate.

Abstract: Provided is an alumina-based sulfur recovery catalyst as well as its preparation method, characterized in that the catalyst has a specific surface area of at least about 350 m2/g, a pore volume of at least about 0.40 ml/g, and the pore volume of pores having a pore diameter of at least 75 nm comprises at least about 30% of the pore volume. The alumina-based catalyst according to present invention is made from flashed calcined alumina, pseudoboehmite and optionally, a binder. The present invention further relates to an use of the alumina-based sulfur recovery catalyst and a method for recovering sulfur by using this catalyst.

Abstract: A single step process for degrading plastic waste by converting the plastic waste into carbonaceous products via thermal decomposition of the plastic waste by placing the plastic waste into a reactor, heating the plastic waste under an inert or air atmosphere until the temperature of about 700° C. is achieved, allowing the reactor to cool down, and recovering the resulting decomposition products therefrom. The decomposition products that this process yields are carbonaceous materials, and more specifically carbon nanotubes having a partially filled core (encapsulated) adjacent to one end of the nanotube. Additionally, in the presence of a transition metal compound, this thermal decomposition process produces multi-walled carbon nanotubes.

Abstract: The present invention provides a process for the selective oxidation of hydrogen sulphide in a hydrogen sulphide-containing hydrocarbon and/or hydrogen feed gas to elemental sulphur in a reaction zone containing a Claus catalyst, comprising the steps of: i) reacting in the reaction zone the hydrogen sulphide in the hydrogen sulphide-containing hydrocarbon and/or hydrogen feed gas with sulphur dioxide at a pressure in the range of from 4 to 200 bar (absolute) and a temperature in the range of from 120 and 160° C., such that the elemental sulphur formed is essentially in liquid form; ii) contacting the catalyst with a reducing atmosphere at elevated temperatures.

Abstract: The present invention provides a method of treating a raw syngas stream and an apparatus therefor. In the method a raw syngas stream is passed to a hydrolysis unit to provide a hydrolysed syngas stream and a condensed water stream. The hydrolysed syngas stream is passed to an acid gas removal unit to separate H2S and a part of the CO2 from the hydrolysed syngas stream to provide a treated syngas stream and an acid off-gas stream. The acid off-gas stream and a sulphur dioxide-comprising stream are passed to a catalytic zone to react H2S in the acid off-gas stream with SO2 in the sulphur dioxide-comprising stream to provide an elemental sulphur stream and a catalytic zone off-gas stream.

Abstract: A process for removing CO2 from a gas containing CO2 by reacting it with a magnesium silicate mineral suspended in a molten salt and additionally a process for converting coal or other fossil fuel to hydrogen by reaction the fossil fuel or coal with water in a molten salt at elevated temperatures in the presence of a magnesium silicate mineral suspended in the molten salt wherein the magnesium silicate reacts with CO2 produced in the reaction, thus removing it from the hydrogen product

Abstract: A feed gas comprising CO2, H2S and H2 is treated to produce an H2-enriched product and a CO2 product. The feed gas is separated by pressure swing adsorption to provide a stream of the H2-enriched product, and two streams of sour gas depleted in H2 and enriched in H2S and CO2 relative to the feed gas. One of the streams of sour gas is processed in an H2S to elemental sulfur conversion system, in which H2S in the sour gas is converted to elemental sulfur order to obtain a stream of sweetened gas, from which the CO2 product is formed. The other of said streams of sour gas is processed in an oxidation system, in which H2S in the sour gas is oxidized to SOx(SO2 and SO3) which is introduced into the H2S to elemental sulfur conversion system.

Abstract: A feed gas comprising CO2, H2S and H2 is treated to produce an H2-enriched product and an H2S-lean, CO2 product. The feed gas is separated to provide the H2-enriched product and a stream of sour gas. The stream of sour gas is divided into two parts, one of which is processed in an H2S removal system to form one or more streams of sweetened gas, and the other of which bypasses the H2S removal system, the stream(s) of sweetened gas and the sour gas bypassing the H2S removal system then being recombined to form the H2S-lean, CO2 product gas. The division of the sour gas between being sent to and bypassing the H2S removal system is adjusted responsive to changes in the H2S content of the sour gas, so as to dampen or cancel the effects of said changes on the H2S content of the H2S-lean, CO2 product gas.

Abstract: A feed gas comprising CO2, H2S and H2 is treated to produce an H2-enriched product and a CO2 product. The feed gas is separated by pressure swing adsorption to provide a stream of the H2-enriched product, and two streams of sour gas depleted in H2 and enriched in H2S and CO2 relative to the feed gas. One of the streams of sour gas is processed in an H2S to elemental sulfur conversion system, in which H2S in the sour gas is converted to elemental sulfur order to obtain a stream of sweetened gas, from which the CO2 product is formed. The other of said streams of sour gas is processed in an oxidation system, in which H2S in the sour gas is oxidized to SOx (SO2 and SO3), the SO2 from the oxidation effluent or sulfuric/sulfurous acid obtained therefrom being introduced into the H2S to elemental sulfur conversion system as a reagent.

Abstract: The present invention provides a process for the selective oxidation of hydrogen sulphide contained in a hydrogen sulphide-containing hydrocarbon feed gas to elemental sulphur. The hydrogen sulphide-containing hydrocarbon feed gas and a sulphur dioxide-containing gas are supplied to a reaction zone containing a TiO2-comprising catalyst, wherein elemental sulphur and a gaseous stream depleted in hydrogen sulphide are formed. The gas feeds are contacted with the TiO2 containing catalyst at elevated pressure and at a temperature in the range of from 120 and below 160° C., under such conditions that the elemental sulphur formed is essentially in liquid form. At least part of the sulphur dioxide-containing gas is obtained by combusting elemental sulphur to obtain a gaseous mixture of sulphur dioxide and nitrogen and then concentrating the gaseous mixture to provide the sulphur dioxide-containing gas.

Abstract: Configurations herein include a novel process and apparatus for generating and maintaining sulfur trioxide gas. The generation system and process operate to provide sulfur trioxide calibration gas for calibrating sulfur trioxide detection devices. The system and process provides a known, concentration of sulfur trioxide gas via a heated catalyst, which enables accurate calibration of measurement equipment. The system functions in part by controlling temperature, amount of moisture, residence time, catalyst selection, diluting generated sulfur trioxide and by locating the sulfur trioxide generator at a point of injection of a sulfur trioxide detection system.

Abstract: A process for removal of H2S and CO2 from an acid gas stream comprising H2S and CO2, the process comprising the steps of: (a) reacting H2S in the acid gas stream with SO2 to form sulphur vapour and water vapour, thereby obtaining a first off-gas stream comprising CO2, water vapour, sulphur vapour, residual SO2 and residual H2S; (b) converting residual SO2 in the first off-gas stream to H2S in a first off-gas treating reactor, thereby obtaining a second off-gas stream depleted in SO2 and enriched in H2S and CO2 compared to the first off-gas stream; (c) contacting the second off-gas stream with an H2S absorbing liquid, thereby transferring H2S from the gas stream to the H2S absorbing liquid to obtain H2S absorbing liquid enriched in H2S and a third off-gas stream enriched in CO2; (d) removing CO2 from the third off-gas stream by contacting the third off-gas stream with CO2 absorbing liquid in a CO2 absorber, thereby transferring CO2 from the third off-gas stream to the CO2 absorbing liquid to obtain CO2 absorbi

Abstract: A process for reducing hydrogen sulfide from a gas comprising contacting the gas with an aqueous scrubbing liquid recycled from a sour water stripper. The aqueous scrubbing liquid comprises ammonia. The contacting of the gas with the aqueous scrubbing liquid thereby produces a semi-sweet gas with reduced concentration of hydrogen sulfide and a rich liquid solution.

Abstract: Reversible acid-gas binding organic liquid systems that permit separation and capture of one or more of several acid gases from a mixed gas stream, transport of the liquid, release of the acid gases from the ionic liquid and reuse of the liquid to bind more acid gas with significant energy savings compared to current aqueous systems. These systems utilize acid gas capture compounds made up of strong bases and weak acids that form salts when reacted with a selected acid gas, and which release these gases when a preselected triggering event occurs. The various new materials that make up this system can also be included in various other applications such as chemical sensors, chemical reactants, scrubbers, and separators that allow for the specific and separate removal of desired materials from a gas stream such as flue gas.

Abstract: All sulfur compounds can be efficiently removed from natural gas that contains hydrogen sulfide and other sulfur compounds such as mercaptan without using physical absorption. The process comprises an absorption step of treating natural gas by means of a chemical absorption method using an amine-containing solution to mainly remove hydrogen sulfide and carbon dioxide, an adsorption step of flowing the natural gas from the absorption step through a packed bed of a molecular sieve to mainly remove mercaptan, a recovery step of recovering sulfur compounds by converting the hydrogen sulfide removed in the absorption step into sulfur by means of the Claus process, a regeneration step of desorbing the mercaptan adsorbed on the molecular sieve in the adsorption step using heated gas and a reaction step of converting the mercaptan in the regeneration exhaust gas exhausted from the regeneration step into hydrogen sulfide.

Abstract: A process for desulfurizing an SO2-comprising gaseous stream comprising the steps of: a. providing an aqueous feed comprising an anion selected from a group consisting of carbonate, bicarbonate, hydroxide, sulfite, and hydrogen sulfite; b. providing an SO2-comprising gaseous feed; and c. contacting the aqueous feed and the gaseous feed to generate a desulfurized gaseous product comprising less than 40% of the feed SO2 content, and an aqueous product; wherein the contacting is carried out in a cyclone unit comprising a housing defined by a cylindrical peripheral wall and provided with at least one inlet opening for receiving fluids thereinto and with at least one swirling means, and wherein the cyclone unit is characterized in that the velocity of the gaseous stream inside the cyclone unit is between 20 m/sec and 120 m/sec.

Abstract: A process for substantially removing carbonaceous material from a composition comprising providing the composition having carbonaceous material, reacting the carbonaceous material with a sulfur compound, and forming products having carbon and sulfur, and the resulting composition and system used therefore.

Abstract: Carbon dioxide contained within exhaust gas is combined with bivalent metal ions such as calcium ions or the like in concentrated salt water to form precipitated calcium carbonate and then can be expelled out. Such an environmental friendly design is realized by a bottle upside down device with a bottle neck exit on a bottom. A piston inside the device can be elevated to a top portion to produce a near vacuum air pressure inside the device. All the brine, exhaust gas, and oxygen, ozone drawn together into the device can be accelerated to form, at least, precipitated calcium carbonate to reduce carbon dioxide contained within the exhaust gas. Chemical reaction is accelerated by a high voltage discharger below the piston and by flashing a portion of water to atomize the brine. A heater can heat up the near vacuum device to accelerate chemical reaction.

Abstract: A process for treating acid gas comprising hydrogen sulfide comprises introducing a first acid gas into a reducing furnace to produce a first oxidized gas stream, cooling the first oxidized gas stream in a first heat recovery system, introducing the cooled gas stream into an oxidizing furnace to produce a second oxidized gas stream and cooling the second oxidized gas stream in a second heat recovery system. The acid gas is preferably produced in a refinery after treatment of sour gas or sour water. Spent acid may be fed into oxidizing furnace as part of a sulfuric acid recovery process. The spent acid can be spent sulfuric acid from a sulfuric acid alkylation process.

Abstract: A process for producing a purified gas stream from a feed gas stream comprising contaminants, the process comprising the steps of: (a) removing contaminants from the feed gas stream to obtain the purified gas stream and a sour gas stream comprising H2S and RSH; (b) separating the sour gas stream comprising H2S and RSH into a gas stream enriched in H2S and a residual gas stream comprising RSH; (c) converting H2S in the gas stream enriched in H2S to elemental sulphur in a Claus unit, thereby obtaining a first off-gas stream comprising SO2; (d) converting SO2 in the first off-gas stream comprising SO2 to H2S in a Claus off-gas treating reactor to obtain a second off-gas stream comprising H2S; (e) converting RSH from the residual gas stream comprising RSH to H2S in an RSH conversion reactor to obtain a residual gas stream comprising H2S, wherein at least one of the operating conditions of the RSH conversion reactor is different from the corresponding operating condition of the Claus off-gas treating reactor.

Abstract: Processes for selectively removing sulfur-containing compounds from a gas are described herein. The processes generally include contacting a first gas including carbon dioxide and hydrogen sulfide with a scrub solution including ammonium bisulfite and ammonium sulfite in a first contact zone to produce a first contact zone effluent liquid including ammonium thiosulfate and a first contact zone overhead gas in which the concentration of hydrogen sulfide is substantially reduced.

Abstract: There is described a novel process for removing sulphurous compounds from industrial gaseous streams, such as sour gas, using an oxygen deficient environment during the oxidation of H2S, and further recycling of any unconverted H2S back to a regenerator.

Abstract: Processes for selectively removing sulfur-containing compounds from a gas are described herein. The processes generally include contacting a first gas including carbon dioxide and hydrogen sulfide with a scrub solution including ammonium bisulfite and ammonium sulfite in a first contact zone to produce a first contact zone effluent liquid including ammonium thiosulfate and a first contact zone overhead gas in which the concentration of hydrogen sulfide is substantially reduced.

Abstract: Improvements in methods by which new or used coal fired boilers whether designed for coal or oil or natural gas firing can substantially improve their technical operation and reduce their capital and operating costs by implementing process steps that (a) minimize the adverse impacts of coal ash and slag on boiler surfaces and particulate emissions, which will improve coal combustion efficiency and facilitate the use of oil or gas designed boilers for coal firing, (b) drastically reduce the loss of water used to transport coal in slurry form to power plants, (c) minimize the combined total nitrogen oxides (NOx), sulfur dioxide (SO2), mercury (Hg), and carbon dioxide (CO2) emissions, (d) separate and permanently sequester carbon dioxide and (e) improve the coal and solid fuel combustion efficiency.

Abstract: Processes for selectively removing sulfur-containing compounds from a gas are described herein. The processes generally include contacting a first gas including carbon dioxide and hydrogen sulfide with a scrub solution including ammonium bisulfite and ammonium sulfite in a first contact zone to produce a first contact zone effluent liquid including ammonium thiosulfate and a first contact zone overhead gas including carbon dioxide.

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 controller directs the operation of an air pollution control (APC) system having one or more controllable operating parameters and a defined operating limit representing a regulatory limit on an allowed amount of pollutant to be emitted by the APC system. An interface receives data representing a value of a regulatory credit available for emitting less of the pollutant than the regulatory limit on the allowed amount of pollutant. A control processor (i) determines a target set point for each of at least one of the one or more controllable operating parameters, which will maximize the regulatory credits earned, based on the received data and (ii) to directs control of each of the at least one controllable operating parameter based on the determined target set point for that parameter.

Abstract: This invention relates to a sulfur tolerant, dynamic, compact, lightweight fuel process and system that is capable of converting sulfur bearing carbonaceous fuels to hydrogen rich gases suitable for fuel cells or chemical processing applications. The process and system is based on the AHR and WGS reactions, followed by cleanup of byproduct sulfur-containing gases and carbon oxides that would otherwise poison the fuel cell electrocatalyst. Advantageously, this is accomplished via an ASMS and a methanator or an AWMR. The process and system preferably uses a special sulfur tolerant catalysts and hardware designs that enable the conversion in an energy efficient manner while maintaining desirable performance characteristics such as rapid start-stop and fast response to load change capabilities.

Abstract: A process for removing H2S from a gaseous stream, wherein the gaseous stream is flowed through an absorber vessel where the stream is contacted with a sorbing liquor comprising a nonaqueous solvent containing dissolved sulfur, a tertiary amine base having sufficient strength and concentration to drive the reaction between H2S sorbed by the liquor and the dissolved sulfur to form a nonvolatile polysulfide which is soluble in the sorbing liquor, and a solubilizing agent for maintaining the solubility of polysulfide intermediates which may otherwise separate. The dissolved nonvolatile polysulfide in the sorbing liquor is converted to sulfur which remains dissolved in the liquor by contacting the liquor with oxidizing sulfur dioxide. The sorbing liquor following the oxidation of the polysulfide is cooled to a temperature at which the liquor is at or above saturation with respect to the dissolved sulfur.

Abstract: A process is provided for producing elemental sulfur from hydrogen sulfide contained in an acid gas feed stream wherein hydrogen sulfide and sulfur dioxide are reacted in a catalytic only sulfur recovery unit comprising a single catalytic converter containing a Claus catalytic reaction zone. A sulfur dioxide-enriched gas recovered from tail gas treatment is recycled and introduced into the catalytic reaction zone as part of a feed gas mixture that also includes the acid gas feed stream. Temperatures within the catalytic reaction zone are effectively moderated by recycle of tail gas effluent to the converter so that high concentrations of hydrogen sulfide in the acid gas feed stream can be tolerated and improved process flexibility and capacity are realized. A pretreatment process including contacting the acid gas with an aqueous acid wash to reduce the concentration of unsaturated hydrocarbons in the acid gas and inhibit deactivation of the oxidation catalyst is also disclosed.

Abstract: H2S is removed from an H2S-rich gas, and sulfur is produced, by a process in which the H2S-rich gas is reacted with SO2 in a reactor in the presence of an organic solvent and a catalyst, an H2S-containing off-gas is removed from the reactor and is combusted to produce an SO2-rich combustion gas. Preferably, the reactor off-gas is combusted with a substoichiometric amount of oxygen so that the combustion gas also contains water vapor and sulfur vapor. The combustion gas is cooled by direct quench or indirect heat exchange to produce an aqueous stream comprising primarily water and containing suspended solid sulfur and polythionic acids, e.g., a Wackenroder's liquid, and the aqueous stream is used to provide cooling for the H2S—SO2 reaction. Problems associated with production and handling of Wackenroder's liquids are overcome and sulfur values in these materials are recovered.

Abstract: A process and system is disclosed for removing sulfur from tail-gas emitted from a Claus sulfur recovery process. First, the tail-gas is oxidized so as to convert sulfur therein to sulfur oxides. Oxidized tail-gas is directed into an absorber where a solid absorbent absorbs substantially all the sulfur oxides thereon. After allowing sufficient time for a desired amount of sulfur oxides to be absorbed, absorption is ceased. Next, the solid absorbent containing the absorbed sulfur oxides is contacted with a reducing gas so as to release an off gas containing hydrogen sulfide and sulfur dioxide. Upon releasing sulfur from the solid absorbent, the solid absorbent is regenerated and redirected into the absorber. Sulfur in the off gas emitted by regeneration is concentrated to an extent sufficient for use within a Claus sulfur recovery process for conversion to elemental sulfur.

Abstract: A process for producing ammonium thiosulfate by contacting a feed gas containing hydrogen sulfide and ammonia with an aqueous absorbing stream containing ammonium sulfite and ammonium bisulfite to form an ammonium thiosulfate-containing solution; the absorption being controlled by monitoring the oxidation reduction potential of the absorbing stream and varying the feed rates in response to the oxidation reduction potential measurements. An ammonium bisulfide-containing aqueous stream is contacted with and absorbs sulfur dioxide to form an aqueous stream containing the ammonium sulfite and ammonium bisulfite reagents. This sulfite/bisulfite-containing stream is combined with the ammonium thiosulfate-containing solution in a vessel to produce a combined solution. A portion of the combined solution is recycled back to contact the feed gas and ammonium thiosulfate is recovered from the remaining portion of the combined solution.

Abstract: Methods for inhibiting pyrophoric iron sulfide activity are disclosed. Methods are disclosed for inhibiting the oxidation of iron sulfide to inhibit pyrophoric activity. The methods comprise contacting iron oxides and/or iron sulfide with a liquid, solution, aerosol, or gaseous inhibitor comprising aromatic hydrocarbons such as alkyl substituted benzenes.

Abstract: A process is provided for the catalytic removal of sulfur compounds, such as hydrogen sulfide and sulfur dioxide, out of a gas by contacting the gas with catalyst composition containing a silicon carbide support and a catalyst component, such as a salt or elemental state of a metal, such as titanium, zirconium, yttrium, lanthanum, uranium, lead, molybdenum, iron, cobalt, copper, nickel, zinc and cadmium and an oxide of a metal, such as uranium, lead, calcium, magnesium and cadmium. The process may be conducted at a temperature above or below the dew point of sulfur.

Abstract: The invention relates to a process for the desulfurization of a crude gas stream containing at least H.sub.2 S in a Claus plant, afterburning of Claus waste gas, and gas washing of the waste gas from the afterburning to remove SO.sub.2, in which SO.sub.2 recovered by the gas washing is recycled to a point before the Claus plant. According to the invention, within the Claus plant, between 60% and 90%, preferably between 67% and 85%, and especially preferably between 67% and 80% of the sulfur contained in the crude gas is separated directly from the crude gas, and between 33% and 10%, preferably between 25% and 10%, and especially preferably between 20% and 15% of the sulfur originally contained in the crude gas is recycled as SO.sub.2. The gas washing to remove SO.sub.2 is advantageously carried out with an absorbing agent having a physical action. A partial stream of the crude gas can be conveyed directly into the afterburning, bypassing the Claus plant.

Abstract: With sufficient oxygen but with no added fuel gas, recovering sulfur from a gas stream containing hydrogen sulfide by oxidizing the gas stream with heat exchange from heat generated in a thermal converter section of a sulfur recovery unit to convert the hydrogen sulfide in the gas stream to sulfur oxide, and thus form a sulfur oxide enriched gas stream. The sulfur oxide enriched gas stream is contacted with a solid adsorbent bed to extract the sulfur oxides and retain them as sulfur compounds, thus forming a sulfur oxide depleted gas stream. The adsorbent bed is then contacted with a reducing gas stream to reduce the retained sulfur compounds to hydrogen sulfide and/or sulfur dioxide and thereby form a hydrogen sulfide and/or sulfur dioxide bearing stream. Sulfur is recovered from the hydrogen sulfide and/or sulfur dioxide bearing stream, and the sulfur oxide depleted gas stream maybe sent to an incinerator or vented through a stack.

Abstract: A process is provided for the production of sulphur from at least one sour gas containing H.sub.2 S and a gaseous or liquid fuel effluent, of the type comprising a thermal reaction step, wherein the thermal reaction step is conducted by performing the combustion of the gaseous or liquid fuel effluent in a first zone of the thermal reaction stage with a quantity of a gas containing free oxygen in excess in relation to the theoretical quantity needed for a complete combustion of the fuel effluent, the excess being smaller than the theoretical proportion of gas containing free oxygen needed to oxidize to SO.sub.2 approximately one third of the H.sub.

Abstract: A process is provided for the improvement of the sulphur yield of an assembly which produces sulphur from H.sub.2 S and which consists of a sulphur plant (1), an oxidation and hydrolysis unit (2) and a purification unit (3). The sulphur plant in producing sulphur provides a residual gas which incorporates H.sub.2 O, COS and/or CS.sub.2 and H.sub.2 S and SO.sub.2 in a mol ratio of H.sub.2 S:SO.sub.2 >2:1. The residual gas passes into the hydrolysis unit on a H.sub.2 S oxidation and COS and CS.sub.2 hydrolysis catalyst which functions between 180.degree. C. and 700.degree. C., in the presence of air, thus producing a residual gas free of COS and CS and incorporating H.sub.2 S and SO.sub.2 in a mol ratio which is kept equal to 2:1 by regulating the air flow. The residual gas is introduced into the purification unit in which H.sub.2 S and SO.sub.2 are made to react in order to produce sulphur and to obtain a purified residual gas.

Abstract: An improved oxygen-enhanced Claus process for the recovery of sulphur from an acid gas comprising hydrogen sulphide as a furnace in which a part of the hydrogen sulphide content of the acid gas is burned to form sulphur dioxide. The sulphur dioxide then reacts with residual hydrogen sulphide to form sulphur vapor which is condensed out of the resulting gas mixture. One part of the residual gas mixture is then subjected to catalytic stages to bring the reaction between the hydrogen sulphide and sulphur dioxide close to completion. The improvement resides in sending a second part of the gas mixture to an incinerator to convert all its hydrogen sulphide content to sulphur dioxide. After removal of water, the sulphur dioxide is returned to the furnace.