Abstract: An object of the present invention is to provide a hydrogen sulfide production method enabling efficient recovery of sulfur. The production method is a method for producing hydrogen sulfide from sulfur and hydrogen comprising (1) a reaction step of reacting sulfur and hydrogen to obtain a crude hydrogen sulfide gas, (2) a purification step of purifying the crude hydrogen sulfide gas by bringing the crude hydrogen sulfide gas into contact with aliphatic lower alcohol in a packed tower to precipitate sulfur contained in the crude hydrogen sulfide gas, (3) a discharge step of discharging from inside the packed tower a suspension of sulfur in aliphatic lower alcohol obtained in the purification step, and (4) a filtration step of filtering the aliphatic lower alcohol suspension of sulfur with a filter to obtain a sulfur cake, and the filter 20 is a rotary filter 22 or a leaf filter.

Abstract: A process for recovering sulfur and carbon dioxide from a sour gas stream, the process comprising the steps of: providing a sour gas stream to a membrane separation unit, the sour gas stream comprising hydrogen sulfide and carbon dioxide; separating the hydrogen sulfide from the carbon dioxide in the membrane separation unit to obtain a retentate stream and a first permeate stream, wherein the retentate stream comprises hydrogen sulfide, wherein the permeate stream comprises carbon dioxide; introducing the retentate stream to a sulfur recovery unit; processing the retentate stream in the sulfur recovery unit to produce a sulfur stream and a tail gas stream, wherein the sulfur stream comprises liquid sulfur; introducing the permeate stream to an amine absorption unit; and processing the permeate stream in the amine absorption unit to produce an enriched carbon dioxide stream.

Abstract: This invention relates to processes for selective removal of contaminants from effluent gases. A sulfur dioxide absorption/desorption process for selective removal and recovery of sulfur dioxide from effluent gases utilizes a buffered aqueous absorption solution comprising weak inorganic or organic acids or salts thereof, to selectively absorb sulfur dioxide from the effluent gas. Absorbed sulfur dioxide is subsequently stripped to regenerate the absorption solution and produce a sulfur dioxide-enriched gas. A process for simultaneous removal of sulfur dioxide and nitrogen oxides (NOx) from effluent gases and recovery of sulfur dioxide utilizes a buffered aqueous absorption solution including a metal chelate to absorb sulfur dioxide and NOx from the gas and subsequently reducing absorbed NOx to form nitrogen. A process to control sulfate salt contaminant concentration in the absorption solution involves partial crystallization and removal of sulfate salt crystals.

Abstract: Generally, the present invention relates to the selective removal of divalent sulfur oxyanions (e.g., sulfate) from an aqueous solvent using an anion exchange resin. More particularly, this invention relates to regenerative processes for the selective removal and recovery of sulfur dioxide from a source gas using an aqueous absorption medium in which an anion exchange resin is used to selectively remove divalent sulfur oxyanion impurities accumulating in the recirculating aqueous absorption medium.

Abstract: A process and apparatus for the treatment of a gas that contains hydrogen sulfide and sulfurous anhydride, in which: a) the gas (3) contacts with an organic solvent (1) containing a catalyst in a gas-liquid reactor-contactor (2) so as to recover separately liquid sulfur and; a gas effluent containing sulfur vapor; subjecting the gas effluent to a first condensation zone (7) operating at 70-100° C. to deposit the sulfur in solid form on sufficiently cold walls of the equipment in zone (7), recovering resultant purified gas containing less than 30 ppm by volume of sulfur melting the deposited solid sulfur to regenerate the equipment, and recycling resultant liquefied sulfur to the reactor contactor.

Abstract: A process for treating a gas containing hydrogen sulphide (H2S) and sulphur dioxide, contacting the gas at a suitable temperature with an organic solvent containing at least a soluble catalytic system, comprising at least one compound comprising at least one functional group A consisting of a carboxylic acid function and at least one functional group B comprising at least one nitrogen atom and which can produce an acid-base type reaction with at least one functional group A under the operating conditions of said process; and recovering a gaseous effluent substantially depleted in hydrogen sulphide and sulphur dioxide along with liquid sulphur separated from the solvent by liquid-liquid decantation.

Abstract: H2S-containing gases, particularly such gases at elevated pressure, are treated to remove H2S by reaction in a liquid medium with SO2, the SO2 being present in stoichiometric excess with respect to the H2S. The SO2 is produced by combustion of sulfur, preferably sulfur produced in the reaction between H2S and SO2, preferably with oxygen. The process produces a treated gas that is substantially free of both H2S and SO2. An acid-gas absorber/stripper system or other system typically found in such processes to raise or concentrate the H2S level in the gas to be treated, is not needed in operations according to the invention.

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 desulphurizing composition for the treatment of CLAUS plant tail gases, comprises: an organic solvent A with a boiling point of more than 200° C. at atmospheric pressure; a catalyst composition B of at least one alkali- or alkaline-earth salt (S) of an organic monoacid or an organic polyacid which has at least one dissociation constant value (pK) in the range 2.2 to 8 such as formic acid, acetic acid, ascorbic acid, fumaric acid, maleic acid, malonic acid, oxalic acid, tartaric acid, benzoic acid, salicyclic acid, and sulphosalicyclic acid; at least one complexing agent (C) such as an alkali or alkaline-earth salt or a ferrous or ferric salt of a mono- or poly-aminocarboxylic acid, citric acid, a sulphocyanide ion, a ferrocyanide ion, a ferricyanide ion, a phosphate ion, a pyrophosphate ion, a fluoride ion and/or a thiosulphate ion; and water (W), in the following proportions by weight: S=0.1% to 30%; C=0.001% to 30%; W=balance.

Abstract: Hydrogen sulfide is removed from gas streams by reaction with sulfur dioxide to produce sulfur. The reaction is effected in a reaction medium comprising a non-aqueous Lewis base with a pKb value of about 6 to about 11. The reaction medium possesses a specific combination of properties: a) absorbs sulfur dioxide and reacts chemically therewith to form a reaction product; b) absorbs hydrogen sulfide; c) removes the hydrogen sulfide from the gas stream through contact of the gas stream with the reaction medium in the presence of free sulfur dioxide, and/or the reaction product; d) acts as a catalyst for the overall reaction of the hydrogen sulfide with sulfur dioxide to produce sulfur; and (e) has the capacity to absorb sulfur dioxide in sufficient quantity to remove substantially all the hydrogen sulfide from the gas stream, notwithstanding short term variations in the stoichiometric balance between the hydrogen sulfide and the sulfur dioxide in the reaction medium.

Abstract: Elemental sulfur is recovered from the hydrogen sulfide present in natural gases and other process gases by treating the hydrogen sulfide-containing gas in a series arrangement of a liquid-phase reactor; a furnace and a sulfur dioxide absorber. The hydrogen sulfide-containing gas and a sulfur dioxide-containing gas are fed into the liquid-phase reactor where they are dissolved into a solvent, such as polyglycol monoethers, diethers of ethylene glycol, diethers of propylene glycol, etc., and react in the presence of a catalyst, such as tertiary amine, pyridine, isoquinoline, etc., to produce elemental sulfur. The feed rates of the hydrogen sulfide-containing gas and the sulfur dioxide-containing gas are selected so that there will be an excess of hydrogen sulfide in the solvent thereby ensuring that the reaction products will include, not only the elemental sulfur, but also residual, unreacted hydrogen sulfide.

Abstract: In a known process and system wherein hydrogen sulfide is removed from a gaseous stream, using a non-aqueous scrubbing liquor which can be an organic solvent for elemental sulfur such as a phenylxylyl ethane in which are dissolved sulfur and a reaction-promoting amine base such as a tertiary amine, sulfur dioxide is added to the sulfur-amine nonaqueous sorbent (or advantage is taken of SO2 which may already be present in the gas stream) to obtain better H2S removal, lower chemical degradation rates, and lower rates of formation of byproduct sulfur salts such as sulfates.

Abstract: A process and an apparatus are described for treatment of a gas containing hydrogen sulphide and sulphur dioxide, for example a Claus plant tail gas, in which the gas is brought into contact with an organic solvent (1) e.g. polyethylene glycol 400, containing a catalyst e.g. sodium salicylate, in at least one gas-liquid reactor-contactor (2) and a gas (20) substantially no longer containing hydrogen sulphide and sulphur dioxide is recovered. A single-phase solution (4) of solvent and sulphur is extracted from the reactor-contactor and a portion is cooled in at least one cooling zone (8) to obtain a suspension of sulphur crystals in the solvent, the crystallised sulphur is separated from the solvent in a separation zone (10), the sulphur-depleted solvent (14, 15) is recovered and recycled at least in part to the reactor-contactor (2), and the sulphur (13) is recovered.

Abstract: A method for processing a gas, such as a Claus tail gas, containing at least hydrogen sulfide (H2S) and at least sulfur dioxide (SO2), includes the steps of contacting the gas with a liquid solvent, such as polyethylene glycol, containing at least one catalyst, such as sodium salicylate, in a contacting stage, recovering gaseous effluent substantially containing no hydrogen sulfide and no sulfur dioxide from the contacting stage, and separating liquid sulfur from liquid solvent in a decantation zone beneath the contacting stage.

Abstract: A method for processing a gas containing at least hydrogen sulfide (H2S) and at least sulfur dioxide (SO2), includes the following stages: contacting the gas with a liquid solvent, such as polyethylene glycol, containing at least one catalyst, such as sodium salicylate, in a contacting stage, recovering a gaseous effluent substantially containing no hydrogen sulfide and no sulfur dioxide, and a mixture containing liquid sulfur, liquid solvent and solid by-products such as alkali metal or alkaline earth metal sulfates or thiosulfates, resulting from the degradation of the catalyst, separating the liquid sulfur from the liquid solvent in a decantation zone, extracting a liquid fraction F containing at least the solid by-products from a layer between the liquid solvent and the liquid sulfur in the decantation zone, sending the liquid fraction F to a processing stage distinct from the contacting stage, and recovering at least a stream F, comprising most of the solid by-products and a stream F2 mostly comprising s

Abstract: An apparatus for treating a gas containing hydrogen sulphide and sulphur dioxide, comprising a liquid-gas reactor-contactor (2), means (3) for supplying gas to be treated and means (1) for supplying an organic solvent containing a catalyst, means (25) for recovering sulphur an doutlet means (20) for a gaseous effluent containing sulphur in vapour form, the apparatus being characterized in that it comprises at least one means (7) for contacting and cooling the gaseous effluent, delivering a three-phase effluent, having an inlet connected to the effluent outlet means (20) and to means (6, 13) for recycling a cooling solvent, means (30) for separating said three-phase effluent connected to the cooling means, adapted to separate purified gas from sulphur and comprising means (17) for evacuating purified gas, means (15) for extracting sulphur and means (14) for recovering solvent connected to the means (6, 13) for recycling the cooling solvent.

Abstract: Hydrogen sulfide is removed from gas streams by reaction with sulfur dioxide in an autogeneously-formed aqueous acid medium according to the equation: SO.sub.2 +2H.sub.2 S.fwdarw.2H.sub.2 O+3S the sulfur being removed from the aqueous phase. Carbonyl sulfide and/or carbon disulfide is removed from gas streams by hydrolysis to hydrogen sulfide in the presence of a weak organic base catalyst, such as quinoline, with the hydrogen sulfide reacting with sulfur dioxide to form sulfur.

Abstract: A process for the production of elemental sulphur by reacting hydrogen sulphide with sulphur dioxide in a liquid reaction medium comprising an organic solvent for the two compounds, e.g., ethylene glycol, and containing at least one soluble catalytic basic compound, e.g., sodium salicylate, comprises bringing a gas mixture containing sulphur dioxide and hydrogen sulphide into contact with a co-current of the solvent containing the catalytic basic compound.

Abstract: In a process and apparatus for treating a gas containing hydrogen sulphide and sulphur dioxide, the gas is contacted with an organic solvent (1)for example, a polyalkylene glycol, containing a catalyst for example, an alkaline salt of a week organic acid, in at least one gas-liquid reactor contactor (2) and a gas (20) substantially no longer containing hydrogen sulphide and sulphur dioxide is recovered. The effluent contains sulphur vapor. It is cooled by mixing with a solvent-water mixture (14) or by cooled solvent in a cooling zone (7) to produce a suspension of sulphur crystals in the solvent. The crystallised sulphur is separated from the solvent in a separation zone (30) and the cooled solvent is recycled (13). An effluent (17) which is free of sulphur gas is obtained.

Abstract: In a process for treating a gas containing hydrogen sulphide and sulphur dioxide, such as Claus plant tail gas, to substantially reduce emission of sulphur vapor in the treated gases, the process a characterized in that the gas is brought into contact with a solvent (5) in at least one gas-liquid reactor-contactor (2) and a gas (20) is recovered which is sent to a second reactor (102) where it is brought into contact with solvent (105), the solvent (105) being cooled by suitable means (190), to separate a portion of the sulphur from the solvent. The resultant solvent depleted in sulphur, contacts the gas (20) from the first reactor (2). The gas (120) from the second reactor is highly depleted in sulphur vapor. At least one of the reactors contains a catalyst. The solvent may be insoluble in water, e.g. dodecane, tridecane, naphtha, or soluble in water, e.g. glycerol, thiodiglycol, cyclohexanedimethylethanol, or an acid ester. The catalyst may comprise, e.g.

Abstract: Elemental sulfur is recovered from the hydrogen sulfide present in natural gas or other process gases by passing the hydrogen sulfide contaminated gas through a hydrogen sulfide absorber so as to obtain a natural or other process gas having a diminished amount of hydrogen sulfide and stripping the hydrogen sulfide out the resulting hydrogen sulfide rich solution so as to obtain a hydrogen sulfide rich gas; feeding the hydrogen sulfide rich gas and sulfur dioxide into a reactor so that the following reaction takes occurs, 2H.sub.2 S+SO.sub.2 .fwdarw.3/2S.sub.2 +2H.sub.2 O under such conditions that there is approximately a 50 percent stoichiometric excess of hydrogen sulfide; combusting the residual, unreacted hydrogen sulfide to convert it into sulfur dioxide, and passing the resulting sulfur dioxide back into the reactor where the reaction between hydrogen sulfide and sulfur dioxide occurs.

Abstract: A foul gas containing H.sub.2 S is brought into the presence of SO.sub.2 in a first stage to permit the reaction between SO.sub.2 and H.sub.2 S to form water and elemental sulfur. The SO.sub.2 is solubilized in an absorbent composition which includes a solvent for both SO.sub.2 and H.sub.2 S so that the H.sub.2 S in the foul gas is first solubilized in the absorbent composition where it is then brought into contact with the solubilized SO.sub.2 for reaction between a major portion of the H.sub.2 S and the solubilized SO.sub.2 to form elemental sulfur. The gas is then passed to a second stage where any remaining H.sub.2 S is removed by aqueous catalytic reaction of the type conventional in the prior art. The apparatus utilized to carry out the present invention preferably includes a two stage column in which the first stage provides the absorbent material containing solubilized SO.sub.2 for reaction with the H.sub.2 S of the foul gas. During the SO.sub.2 extraction stage the major portion of the H.sub.

Abstract: Improved processes are disclosed for the removal of hydrogen sulfide from feed streams by conversion of hydrogen sulfide and sulfur dioxide to elemental sulfur and water, e.g. Claus process. The feed stream of the present invention is divided into two split streams wherein one is incinerated to form sulfur dioxide in the presence of oxygen. The sulfur dioxide is then separated from the water, nitrogen and other impurities and combined with the other split stream to form a reactor feed which is passed to a sulfur reaction zone for conversion to elemental sulfur. Due to the rejection of water, nitrogen and other impurities from the reactor inlet stream, a higher concentration of hydrogen sulfide and sulfur dioxide can be achieved in the sulfur reaction zone. As a result, the processes of the present invention can be used to increase the throughput of existing Claus process plants and reduce the size of new Claus process plants.

Abstract: A process of removing hydrogen sulfide from a gas stream in which the hydrogen sulfide is dissolved in an absorption zone by a solvent having a good solvent power for hydrogen sulfide and a much greater solvent power for sulfur dioxide. The resultant solution is divided into a major stream and a minor stream. The major stream is contacted with a small excess of sulfur dioxide over that required for reaction with hydrogen sulfide. Most of this solution is recycled to the absorption zone. The minor stream withdrawn from the absorption zone is mixed with the solution formed in the reaction zone which is not recycled, the proportion being such that there remains a small excess of hydrogen sulfide in solution. This solution is then stripped of hydrogen sulfide. By this means only a small fraction of the solution has to be stripped. Preferred solvents are those which promote the reaction of hydrogen sulfide with sulfur dioxide.

Abstract: Process of treating sulfur containing gas streams by the Claus reaction in which a recycle stream containing a reactive component is employed in a negative feedback mode to maintain the sulfur producing Claus reaction at approximately equilibrium conditions. The feedstream may contain hydrogen sulfide or sulfur dioxide in a minor amount in an inert gas background. In one embodiment the feedstream to the reaction zone contains a stoichiometrically excess amount of sulfur dioxide for the Claus reaction. Effluent from the reaction zone is passed to a hydrogenation zone where the sulfur dioxide is converted to hydrogen sulfide. Hydrogen sulfide is extracted from the hydrogenation zone effluent and recycled to the Claus reaction zone. In another embodiment the feedsteam may contain a stoichiometrically excess amount of hydrogen sulfide.

Abstract: The present invention relates to a chemical process involving a processing step which is sensitive to the presence of at least one component contained within the stream to be processed and to an economical and efficient method of temporarily removing such deleterious component from the stream so as to have the deleterious component by-pass the step which is sensitive to this component using an adsorbent for such removal wherein the adsorbent is regenerated by the product effluent stream leaving the sensitive processing step.

Abstract: A process for the removal of H.sub.2 S from sour gaseous streams is disclosed in which the sour gaseous stream is contacted with a solution containing solubilized iron chelates of nitrilotriacetic acid. The contacting is carried out in first and second contacting zones, the first being a gas-solution mixture formation zone and the second comprising a plurality of contacting sections adapted to provide reaction of the H.sub.2 S in the sour gaseous stream with the iron in the contacting solution without plugging due to deposition of sulfur.

Abstract: A process for the removal of H.sub.2 S from sour gaseous streams is disclosed in which the sour gaseous stream is contacted with a solution containing solubilized iron chelates of a specified organic acid or acids. The contacting is carried out in first and second contacting zones, the first being a gas-solution mixture formation zone and the second comprising a plurality of contacting sections adapted to provide reaction of the H.sub.2 S in the sour gaseous stream with the iron in the contacting solution without plugging due to deposition of sulfur.

Abstract: A process for removal of solid sulfur from specified solubilized iron chelate-containing solutions is described, the process being characterized by melting of the sulfur and maintenance of the solution during the melting and separation operations in the substantial absence of oxygen.

Abstract: For the removal of sulfur compounds, especially H.sub.2 S, from gaseous mixtures, said mixtures are scrubbed with a physical solvent which is later regenerated and reused. To the solvent are added (a) an oxidizing agent for converting the sulfur compounds into elemental sulfur, and (b) additive means for increasing the settling rate of the thus-formed sulfur.

Abstract: A process for removal of solid sulfur from specified solubilized iron chelate-containing solutions is described, the process being characterized by melting of the sulfur and maintenance of the solution during the melting and separation operations in the substantial absence of oxygen.

Abstract: For the removal of sulfur compounds, especially H.sub.2 S, from gases that contain hydrocarbons, and/or CO.sub.2, the gases are scrubbed with a physical solvent, which is to be regenerated and reused. To obtain sulfur free of hydrocarbons, as well as a practically sulfur-free LPG fraction and optionally a C.sub.5+ fraction, an oxidizing agent is added to the solvent for reacting the sulfur compounds to elemental sulfur, and the sulfur is separated. The concomitantly absorbed hydrocarbons and/or CO.sub.2 can then be desorbed from the separated solvent by physical regeneration and can be recovered.

Abstract: The invention relates to a process for the selective removal of hydrogen sulfide from a gaseous stream additionally containing carbon dioxide by contacting the gaseous stream with a polyvalent metal chelate solution for a time sufficient to allow the polyvalent metal chelate to oxidize the hydrogen sulfide to elemental sulfur without allowing the polyvalent metal chelate solution to absorb appreciable amounts of carbon dioxide. The pH of the metal chelate solution should be greater than 7 and the contact time between the polyvalent metal chelate and the gaseous stream is between 0.006 and 0.08 second.

Abstract: For producing elemental sulfur, SO.sub.2 is dissolved in a regenerable solvent, which is treated with a reducing agent, and the thus-formed sulfur is separated from the solution.

Abstract: A process for removing sulfur dioxide from a gas stream by absorption in a buffered, aqueous thiosulfate and polythionate solution followed by regeneration of the enriched solution with hydrogen sulfide to form sulfur wherein excess hydrogen sulfide recovered from the regeneration step is introduced to the absorption step to reduce bisulfite concentration in the enriched solution.

Abstract: A Stretford process for removing hydrogen sulfide from a high volumetric flow gas stream includes devices for introducing transverse momentum components in a multiphase flow. These momentum components enhance gas/liquid contact and improve the efficiency of hydrogen sulfide removal. Various devices for introducing the momentum components are disclosed including baffle trays, static mixer and tertiary spray devices.

Abstract: A process for the simultaneous removal of H.sub.2 S, SO.sub.2 and elemental sulfur from gaseous mixtures, comprises treating the gaseous mixture with a solvent. After the solvent becomes loaded with the components to be removed, it is regenerated and reused. In order to obtain savings in costs and energy, the sulfur is separated from the loaded solvent by lowering the temperature thereof. In this way, chemical regeneration of the scrubbing medium takes place within the cycle eliminating the requirement for outside regenerating apparatus.

Abstract: A process for reacting the H.sub.2 S in H.sub.2 S-bearing gas streams with SO.sub.2 in a solvent to produce elemental sulfur, including the steps of oxidizing approximately 1/3 of the H.sub.2 S in the stream to SO.sub.2, absorbing that SO.sub.2 with a dialkyl alkyl phosphonate absorbent and reacting that SO.sub.2 with the remaining H.sub.2 S from the stream in the presence of the phosphonate solvent, thereby forming elemental sulfur and water.

Abstract: Aqueous solutions comprising from about 35 to about 85% by weight of an alkanolaminium carboxylate have proven to be highly efficient absorption solvents for sulfur dioxide. Such solvents preferentially absorb sulfur dioxide from the gas streams containing large quantities of carbon dioxide. The rate at which dissolved sulfur dioxide oxidizes to non-regenerable sulfate salts is significantly reduced by such solvents.

Abstract: Preferential sulfur dioxide absorption solvents may be buffered with suitable agents, such as alkanolaminium carboxylates, to substantially retard or eliminate the tendency of such solvents to degrade or accumulate non-regenerable salts, particularly sulfates, when loaded with absorbed sulfur dioxide. A method for employing the buffer as an immiscible aqueous phase as a separate trimming solvent to selectively absorb residual sulfur dioxide from a gas stream from which the bulk amount of sulfur dioxide is first removed by contact with a trialkyl phosphate solvent is disclosed. The method permits the trialkyl phosphate solvent to be regenerated and purged of salts at lower energy requirements.

Abstract: Preferential sulfur dioxide absorption solvents may be buffered with suitable agents, such as alkanolaminium carboxylates, to substantially retard or eliminate the tendency of such solvents to degrade or accumulate non-regenerable salts, particularly sulfates, when loaded with absorbed sulfur dioxide. A method for employing the buffer as an immiscible aqueous phase as a separate trimming solvent to selectively absorb residual sulfur dioxide from a gas stream from which the bulk amount of sulfur dioxide is first removed by contact with a trialkyl phosphate solvent is disclosed. The method permits the trialkyl phosphate solvent to be regenerated and purged of salts at lower energy requirements.

Abstract: At least one of sulfur dioxide and a gaseous hydrosulfide is contacted with at least one of a sulfur-containing salt and a gaseous basic nitrogen compound to produce a solid, sulfur-containing composition.

Abstract: A nitrogen base is separated from the sulfur-containing product of a gas phase reaction between a basic nitrogen compound and at least one of a hydrosulfide and sulfur dioxide by washing the product of the reaction, followed by basification and stripping of the wash liquid. In another embodiment, the nitrogen base is displaced from the sulfur-containing product with anhydrous ammonia.

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: A buffer solution containing glycerol is used for removing sulfur dioxide from waste gases. Sulfur is recovered from the glycerol-buffer solution having sulfur dioxide absorbed therein, by reaction with hydrogen sulfide.

Abstract: Sulfur dioxide is removed from a sulfur dioxide-containing gas mixture by contacting the gas mixture with a monoolefin or diolefin.

Abstract: Hydrogen sulfide is removed from a three-phase mixture of crude oil, natural gas, and water as it issues as a stream from an oil well by first adding liquid sulfur dioxide to the stream without substantially changing its temperature or pressure and then turbulencing the stream to react most of the hydrogen sulfide therein with the sulfur dioxide. Water containing an additive capable of forming a salt with the remaining trace hydrogen sulfide is then added to the stream and then the desulfurized natural gas is separated out of the stream. Hot and sulfur-free crude oil is then injected into the stream to melt the sulfur therein and the stream is then gravitationally separated into sulfur, water, and pure sulfur-free crude oil, some of the last of which is heated and reintroduced into the stream upstream to heat same and melt the sulfur therein.

Abstract: In a low temperature gas scrubbing process with a physical scrubbing solution, e.g., methanol, wherein either the H.sub.2 S containing gas-to-be-scrubbed, e.g., coal gasification gas, has a sufficient concentration of SO SO.sub.2 and/or O.sub.2 or wherein the H.sub.2 S containing scrubbing solution is brought into contact with a second O.sub.2 and/or SO.sub.2 containing gas, e.g. a stripping gas, to form elemental sulfur in the scrubbing solution, and said scrubbing solution is regenerated and then cooled to the scrubbing temperature, the improvement which comprises adding a sufficient amount of cyanides to the scrubbing solution to convert the elemental sulfur to thiocyanate, whereby sulfur is not precipitated in the scrubbing solution which would have otherwise occured, and removing the thiocyanate at least partially from the scrubbing solution. The cyanides may be added to the gas-to-be-scrubbed or the scrubbing solution, or there may be sufficient hydrocyanic acid in the gas-to-be-scrubbed at the outset.

Abstract: Advantageously the absorption solution is glutaric acid buffered to a pH of about 3.5 to 6.5, the concentration of the glutaric acid is from about 40% up to 90% of the saturation concentration, its temperature is from about 20 to 25.degree. C, it has a concentration of heavy metal ions no more than about 10.sup.-6 mole/l, and to improve the separation of SO.sub.2 from the absorption solution steam is introduced into at least one separator in from about 0.01 to 0.1 kg/l of solution to be desorbed.

Abstract: Hydrogen sulfide is substantially completely removed from a sulfur bearing industrial gas stream by absorbing the H.sub.2 S into a liquid absorbent, stripping the absorbent of absorbed H.sub.2 S and reacting it with SO.sub.2 in a ratio of H.sub.2 S/SO.sub.2 greater than the stoichiometric ratio of 2.0:1.0 to produce elemental sulfur and water, leaving a tail gas containing an excess of hydrogen sulfide but no sulfur dioxide. At least the last stage of the reaction is carried out in a liquid reaction medium at a temperature not greater than 160.degree. C. The excess H.sub.2 S assures complete reduction at these temperatures of all SO.sub.2 to elemental sulfur. The remaining excess H.sub.2 S is then recycled in the tail gas back into the original industrial gas stream prior to the point of contact of the industrial gas stream with the liquid absorbing solution.