Abstract: The selective removal of H.sub.2 S gas from a normally gaseous mixture containing H.sub.2 S and CO.sub.2 is accomplished by contacting the gaseous mixture with an absorbent solution comprising a severely sterically hindered secondary amino compound having a cumulative .sup.- E.sub.s value (Taft's steric hindrance constant) greater than about 1.75 whereby H.sub.2 S is selectively absorbed from the mixture.

Abstract: The selective removal of H.sub.2 S gas from a normally gaseous mixture containing H.sub.2 S and CO.sub.2 is accomplished by contacting the gaseous mixture with an absorbent solution comprising a di-secondary aminoether wherein each amino group has a severely sterically hindered secondary amino moiety whereby H.sub.2 S is selectively absorbed from the mixture.

Abstract: A combination moisture and hydrogen getter comprises(a) a moisture getter comprising a readily oxidizable metal; and(b) a hydrogen getter comprising (i) a solid acetylenic compound and (ii) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the resultant hydrogen.

Abstract: The selective removal of H.sub.2 S gas from a normally gaseous mixture containing H.sub.2 S and CO.sub.2 is accomplished by contacting the gaseous mixture with an absorbent solution comprising a severely sterically hindered secondary aminoether alcohol having a cumulative .sup.- -E.sub.s value (Taft's steric hindrance constant) greater than about 1.75 whereby H.sub.2 S is selectively absorbed from the mixture.

Abstract: The selective removal of H.sub.2 S gas from a normally gaseous mixture containing H.sub.2 S and CO.sub.2 is accomplished by contacting the gaseous mixture with an absorbent solution comprising a tertiary amino azabicyclic alcohol whereby H.sub.2 S is selectively absorbed from the mixture.

Abstract: The present invention relates to an alkaline promoter system comprising specific mixtures of nonsterically hindered amino compounds and sterically hindered amino acids and their use in acid gas scrubbing processes. The preferred promoter system comprises a mixture of (i) diethanol amine or 1,6-hexanediamine and (ii) N-secondary butyl glycine or pipecolinic acid.

Abstract: A cyclic process for the removal of hydrogen sulfide, and carbon dioxide, from a variety of gas streams is disclosed. The gas stream containing the sour gas is contacted with reactant solution containing specified reactant materials and a minor amount of a monoalcohol (C.sub.n H.sub.2n+1 OH, where n is 4 through 18) crystal modifier. The hydrogen sulfide is converted to sulfur, CO.sub.2 is absorbed to produce a purified gas stream, the reactant material is reduced, and good quality sulfur is produced. The process includes removal of the sulfur and regeneration of the reactant.

Abstract: A cyclic process for the removal of H.sub.2 S from gas streams is disclosed, the process being characterized by reaction of the H.sub.2 S to sulfur employing specific aqueous solution reactants, and by recovery of the sulfur employing frothing and extraction techniques.

Abstract: A cyclic process for the removal of hydrogen sulfide, and carbon dioxide, from a variety of gas streams is disclosed. The gas stream containing the sour gas(es) is contacted with an aqueous solution of a specific reactant ligands or chelate, or mixtures thereof, optionally in an absorbent, containing specific stabilizers for improvement of chelate life. The hydrogen sulfide is converted to sulfur, CO.sub.2 may be absorbed to produce a purified gas stream, and the reactant chelate is reduced. The process includes sulfur removal and regeneration of the reactant chelate.

Abstract: A process for removing hydrogen sulfide from sour gas streams is provided wherein the sour gas is passed in cocurrent flow relationship with a liquid alkaline absorption solution containing a vanadium-boron complex characterized by the properties of reacting with the H.sub.2 S thereby oxidizing [HS.sup.- ] to elemental sulfur in conjunction with reduction of the vanadium while the boron constituent is functional to inhibit formation of insoluble vanadium sulfide compounds. Regeneration of the absorption medium by contact with an oxygen containing gas is enhanced by the provision of an iron-polyamine organic acid oxidation catalyst in the absorption liquid. The process is a direct replacement for and may be operated far more economically than conventional Stretford processes.

Abstract: In the removal of sour gases by scrubbing with an aqueous alkali metal salt solution, e.g. a solution of K.sub.2 CO.sub.3, the circulating scrubbing liquid is gradually contaminated with organic acids, especially formic acid, which in turn ties up K.sup.+ as the formate which is ineffective for scrubbing purposes. To remove the organic acids, at least a partial stream of the circulating scrubbing liquid is subjected to an oxidation step under conditions leading to the oxidation of the salts of the organic acids, thereby liberating the bound alkali metal ions. If the scrubbing liquid contains an oxidizable activator, the latter can be extracted prior to oxidation of the scrubbing liquid and added back subsequent to the oxidation.

Abstract: A method is provided for reconditioning a hydrogen sulfide removal system, such as a Stretford process system in which elemental sulfur is formed, after the system has become contaminated with sulfur-feeding bacteria to an extent that operation thereof is substantially impaired. The method includes adding a bactericide to the washing solution employed in the system to destroy the bacteria and adding a non-ionic surfactant to the solution to remove dead bacteria from the surfaces of particulate sulfur formed in the system so that the particles can agglomerate in the intended manner to enable sulfur removal from the solution.

Abstract: A cyclic process for the removal of H.sub.2 S from gas streams is disclosed, the process being characterized by reaction of the H.sub.2 S to sulfur employing polyvalent metal reactant solutions, and by a novel sulfur recovery scheme. Sulfur recovery, either before or after regeneration, is accomplished by separation of the sulfur-containing admixture into lean and concentrated solutions, and by extracting the concentrated solution with a compound having the formula C.sub.n H.sub.2n+1 OH, wherein n is a number from 4 through 18.

Abstract: A cyclic process for the removal of hydrogen sulfide, and carbon dioxide, from a variety of gas streams is disclosed. The gas stream containing the sour gas(es) is contacted with an aqueous solution of a specific reactant ligand or chelate, or mixtures thereof, optionally in an absorbent, containing specific stabilizers for improvement of chelate life. The hydrogen sulfide is converted to sulfur, CO.sub.2 may be absorbed to produce a purified gas stream, and the reactant chelate is reduced. The process includes sulfur removal and regeneration of the reactant chelate.

Abstract: A side-stream portion of a Stretford Process solution is taken from the main-stream in order to reduce the amount of deleterious side-products in the solution and the ADA values and vanadium values are salvaged from the side-stream by taking up the ADA values on activated charcoal and the vanadium values in an anion exchange resin. The ADA and vanadium values are recovered for re-cycling back to the Stretford Process.

Abstract: Method for enhancing the removal of particles from a particle-laden gas stream utilizing an electrostatic precipitator, which comprises treating the gas with morpholine or derivatives thereof. Treated particles are found to also have desirable flow characteristics. Particularly effective compositions for the purpose comprise a combination of the morpholine, or derivative thereof, with an electrostatic precipitator efficiency enhancer, and in particular an alkanolamine.

Abstract: A distillative separation of carbon dioxide and hydrogen sulfide is improved by adding a C.sub.3 -C.sub.6 alkane, a mixture of C.sub.3 -C.sub.6 alkanes, SO.sub.2 or SO.sub.3 to a distillation column to increase the relative volatility of carbon dioxide to hydrogen sulfide. Increasing the relative volatility facilitates the separation.

Abstract: A cyclic process for the removal of hydrogen sulfide, and carbon dioxide, from a variety of gas streams is disclosed. The gas stream containing the sour gas(es) is contacted with an aqueous solution of a specific reactant ligand or chelate, or mixtures thereof, optionally in an absorbent, containing specific stabilizers for improvement of chelate life. The hydrogen sulfide is converted to sulfur, CO.sub.2 may be absorbed to produce a purified gas stream, and the reactant chelate is reduced. The process includes sulfur removal and regeneration of the reactant chelate.

Abstract: Acidic gases containing carbon dioxide are removed from a normally gaseous mixture by absorbing CO.sub.2 from the gaseous mixture with an aqueous solution comprising a basic alkali metal salt or hydroxide and an activator or promoter system for the salt or hydroxide which contains (i) at least one non-sterically hindered diamine defined as having both a primary and a tertiary amino moiety wherein the primary amino moiety is attached to a primary carbon atom, and (ii) an amino acid, and desorbing at least partially the absorbed CO.sub.2 from the aqueous solution.

Abstract: Acidic gases containing carbon dioxide are removed from a normally gaseous mixture by absorbing CO.sub.2 from the gaseous mixture with an aqueous solution comprising a basic alkali metal salt or hydroxide and an activator or promoter system for the salt or hydroxide which contains (i) at least one diaminoalcohol of the formula:H.sub.2 N--(CH.sub.2).sub.4 --NRR'wherein R and R' each independently represent a C.sub.1 -C.sub.6 alkyl group and either R or R' or both R and R' have a pendant hydroxyl group, and (ii) an amino acid, and desorbing at least partially the absorbed CO.sub.2 from the aqueous solution.

Abstract: An aqueous catalytic oxidation-reduction composition for oxidizing hydrogen sulfide to produce elemental sulfur and a method of removing hydrogen sulfide from a gas stream whereby a gas stream containing hydrogen sulfide is brought into contact with an aqueous catalytic oxidizing reaction composition containing a water soluble polyvalent metal salt having the metal in the higher valent state and at least one surfactant, preferably a low foaming nonionic surfactant, such as a linear alcohol alkoxylate surfactant, which is adapted to wet the elemental sulfur formed and having the surfactant present in the reaction solution in an amount sufficient to prevent formation of sulfur froth on the surface of the reaction solution.

Abstract: A process for the treatment of a gas mixture containing methane and light hydrocarbons is disclosed, the process being characterized in that the gas mixture is treated in two steps consecutively with two different liquid mixtures, each of which contains a physical and chemical absorbent, in the first step H.sub.2 S being selectively removed, in the second step the remaining acid gases being virtually completely removed.

Abstract: A cyclic process for the simultaneous removal of hydrogen sulfide and carbon dioxide from a variety of gas streams is disclosed. The gas stream containing the sour gases is contacted with a solution of the Fe(III) chelate of nitrilotriacetic acid in an absorbent comprising diethylene glycol monoethyl ether. The hydrogen sulfide is converted to sulfur, the CO.sub.2 is absorbed to produce a purified gas stream, and the Fe(III) chelate is converted to the Fe(II) chelate. The process includes sulfur removal and regeneration of the absorbent and the Fe(III) chelate.

Abstract: A method for controlling the concentration of dissolved thiosulfate byproduct which forms in a wet desulfurization process, by introducing a peroxygen chemical into its recirculating aqueous absorption medium. A peroxygen chemical such as aqueous hydrogen peroxide is introduced into the recirculating aqueous alkaline absorption medium, preferably after its regeneration, in an amount sufficient to maintain the concentration of thiosulfate byproduct below a saturation concentration. The method is applicable to cyclic wet desulfurization processes, used to recover elemental sulfur from H.sub.2 S-containing gas streams, in which the absorption medium contains a regenerable oxidizing agent and is subject to thiosulfate byproduct buildup.

Abstract: A thiosulfate-containing purge stream generated in a Stretford-type process for purifying a hydrogen sulfide contaminated gas stream is treated with a nickel ethylenediamine complex to remove thiosulfate as a nickel ethylenediamine thiosulfate precipitate. The precipitate is treated with acid to decompose the thiosulfate and then with lime to recover the nickel ethylenediamine complex for reuse.

Abstract: A process for the conversion of aqueous hydrogen sulfide, bisulfide ion, and sulfide ion in condensed geothermal steam to form less volatile and environmentally less objectionable sulfur compounds comprises reacting such steam components with hydrogen peroxide catalyzed by various iron or nickel compounds. The hydrogen peroxide and catalyst are added to steam condensate after it has been used and before it is returned to a cooling tower where it may be added to other cooling water in a geothermal steam power system. The conversion process prevents the buildup of harmful, contaminating sulfur compounds on system components in the liquid stream and also prevents the release of certain otherwise voltatile components to the atmosphere.

Abstract: The alkanolpyridines, as physical solvents, compare favorably, as a family, with sulfolane in their absorption of hydrogen sulfide and mercaptans. The data show absorption differences of the alkanolpyridines diluted with water, as compared with the alkanolpyridines mixed with amine. Both sets of data indicate an absorption performance substantially equal to, or better than, the performance of sulfolane. The chemical structure of pyridine is shown below. This structure is shown with the understanding that the alkanolpyridines would have the propanol or carbinol radicals, which are also shown, or other alkanol radicals substituted at the 2, 3 or 4 position.

Abstract: Soluble thiosulphates present in aqueous redox systems comprising at least one salt of an anthraquinone di-sulphonic acid and at least one water soluble compound of metal having at least two stable oxidation states, for example a vanadate, are converted to sulphates by introducing oleum or sulphuric acid into the lower half of a vessel containing said thiosulphate containing redox solution, wherein the sulphuric acid has a concentration of from 10-98% w/w H.sub.2 SO.sub.4 and the amount of said sulphuric acid is such that the gram molecular weight ratio of sulphuric acid to thiosulphate is from 1:2 to 1:3, and thereafter separating the sulphate formed for example by using a solubility lowering technique. The process is carried out at ambient temperature and at a temperature of from 70.degree. C. up to the boiling temperature of the acidic mixture.

Abstract: Hydrogen sulfide, carbon dioxide, and carbonyl sulfide are removed from a gas stream in a staged procedure characterized by absorption of the CO.sub.2 and COS and conversion of the hydrogen sulfide to produce sulfur in an absorbent mixture, hydrolysis of the carbonyl sulfide to produce a gas stream of hydrogen sulfide and carbon dioxide, and removal of the hydrogen sulfide from the gas stream.

Abstract: A cyclic process for the removal of hydrogen sulfide from a variety of gas streams is disclosed. The gas stream containing the sour gases is contacted with a solution of the Fe(III) chelate of nitrilotriacetic acid and a modifier having the formula C.sub.n H.sub.2n-1 OH, wherein n is a whole number from 4 through 22. The hydrogen sulfide is converted to sulfur, and the Fe(III) chelate is converted to the Fe(II) chelate. The process includes sulfur removal and regeneration of the Fe(III) chelate.

Abstract: Mixed disulfoanthraquinonemono-, di-, or polycarboxylic acids produced by the direct sulfonation of an anthraquinone of the formula: ##STR1## wherein n is an integer of 1-4 and each R is independently selected from alkyl of 1-4 carbon atoms and chlorine with at least one R being alkyl and with the proviso that substitution in a single ring is limited to mono, di- or tri-substitution and substitution in two rings is limited to mono or di-substitution in each ring.The mixed disulfoanthraquinonemono-, di-, or polycarboxylic acids have exceptional utility in the Stretford Process.

Abstract: In the scrubbing of gases containing sulfur compounds with an aqueous alkaline solution of salts of anthraquinonedisulfonic acid, alkali sulfates are formed during a salt regeneration step, and these sulfates must be kept under a certain upper limit. This is accomplished by subjecting a partial stream of scrubbing solution to combustion under reducing conditions; however, thiosulfate is also removed, resulting ultimately in the decomposition of the anthraquinonedisulfonates. To overcome this drawback, the liquid product withdrawn from the combustion step is contacted with an oxygen-containing gas to convert alkali sulfides and/or alkali hydrogen sulfides contained therein to alkali thiosulfate, preferably in the presence of a catalytic amount of said salts of anthraquinonedisulfonic acid.

Abstract: A cyclic process for the removal of hydrogen sulfide, and carbon dioxide, from a variety of gas streams is disclosed. The gas stream containing the sour gases is contacted with an aqueous solution of specific reactant materials, optionally in an absorbent, containing specific dialcohols for reaction rate improvement. The hydrogen sulfide is converted to sulfur, CO.sub.2 may be absorbed to produce a purified gas stream, and the reactant material is reduced. The process includes sulfur removal and regeneration of the reactant.

Abstract: The foam in acid gas scrubbing solutions created during an acid gas scrubbing process is reduced or eliminated by the addition of certain polyoxyethylene polyoxypropylene block cpolymers as defoaming agents. The defoaming agents are particularly effective when the acid gas scrubbing solution contains an amine having a large hydrophobic moiety.

Abstract: A process for scrubbing acid gases in which carbon dioxide and hydrogen sulfide, for example, are scrubbed from gas mixtures which also contain polymerizable organic components, in which an aqueous alkanolamine, such as ethanolamine, is used as the scrubbing liquid. The scrubbing liquid is heated, regenerated, cooled and returned to the scrubber and the polymerizable component or the polymer formed therefrom is removed by treating the scrubbing liquid with an organic solvent which is water immiscible. The extraction treatment by the organic solvent, according to the invention, is carried out after the heating and before the regeneration of the charged scrubbing liquid at a temperature of the latter which is just below the boiling point of the liquid mixture formed by the scrubbing liquid and the organic extracting solvent.

Abstract: Antifoaming agents for use in acid gas scrubbing processes comprising 1-secondary or 1-tertiary alkyl- or 1-cycloalkyl-hexahydro-2-pyrimidinones and 1-secondary or 1-tertiary alkyl- or 1-cycloalkyl-2-imidazolidinones are disclosed.

Abstract: An aqueous solution containing from 0.81 to 1.3 moles of piperazine per liter is used as a washing agent for removing impurities such as H.sub.2 S, CO.sub.2 and COS from gases. Piperazine can also be used, in amounts of up to 0.8 mole per liter, together with physical or chemical solvents, to accelerate the absorption of H.sub.2 S, CO.sub.2 and COS. The washing process is used for natural gases, coke-oven gases, gases from the gasification of coal and synthesis gases, of any origin.

Abstract: Hydrogen sulfide and carbonyl sulfide are removed from a gas stream in a staged procedure characterized by conversion of the hydrogen sulfide to produce sulfur in aqueous solution, hydrolysis of the carbonyl sulfide remaining in the gas stream to produce hydrogen sulfide and carbon dioxide, and removal of the hydrogen sulfide from the gas stream.

Abstract: Acid gases are separated from gaseous streams by the use of absorbents having the formula ##STR1## wherein R.sub.1, R.sub.2, and R.sub.3 are alkyl containing 1 through 4 carbon atoms.

Abstract: A hydrogen sulfide removal and conversion method in which a hydrogen sulfide-containing gas stream is contacted with a regenerable washing solution containing solubilized vanadium thiocyanate ions, a carboxylate complexing agent and one or more water-soluble quinones capable of solubilizing tetravalent vanadium. The molar ratio of vanadium to quinone(s) in the washing solution is selected to substantially reduce or eliminate the formation of contaminant sulfate salts. The absorbed hydrogen sulfide is converted to elemental sulfur which, after oxidative regeneration of the washing solution, is separated from the regenerated solution.

Abstract: A process for treating a hydrogen sulfide-containing hydrogenated Claus process tail gas to convert the hydrogen sulfide to elemental sulfur in which said gas is contacted with an aqueous alkaline solution containing a water-soluble metal vanadate, a water-soluble anthraquinone disulfonate, and a water-soluble, inorganic fluoride, borate, or phosphate complexing agent to yield an effluent gas to reduced sulfur content. The solution is thereafter regenerated by contact with an oxygen-containing gas, elemental sulfur is recovered from the solution, and the regenerated solution is recycled to the gas-contacting step. The complexing agent contained in the solution reduces the chemical consumption of the anthraquinone disulfonate.

Abstract: A process is disclosed for the purification of an inert or non-reacting gas such as lower mono-olefins by the removal of trace amounts of reacting impurities such as carbon dioxide therefrom, comprising passing said gas through an essentially non-aqueous liquid solution of alkali or alkaline earth metal hydroxides and/or weak acid salts and certain selected liquid polyhydric alcohols.

Abstract: A distillative separation of carbon dioxide and hydrogen sulfide is improved by adding a C.sub.3 -C.sub.6 alkane, a mixture of C.sub.3 -C.sub.6 alkanes, SO.sub.2 or SO.sub.3 to a distillation column to increase the relative volatility of carbon dioxide to hydrogen sulfide. Increasing the relative volatility facilitates the separation.

Abstract: Acid gases, such as CO.sub.2, can be extracted from a gaseous feed stream by contacting the exhausted inlet gas with an aqueous solution of 3-amino-1,2 propanediol, separating the regenerated feed stream from the aqueous amine solution and the acid gases dissolved therein, and further separating these dissolved acid constituents from the diol solution; finally, repeating the above cycle indefinitely.

Abstract: This invention relates to a process for the removal of sulfur compounds from a gas stream which consists of contacting said gas stream with alkali metal salts of sulfonamides or resins containing sulfonamide functionalities.

Abstract: A hydrogen sulfide removal and conversion method in which a hydrogen sulfide-containing gas stream is contacted with a substantially quinone-free aqueous washing solution containing, inter alia, solubilized vanadium, thiocyanate ions, and one or more water-soluble nonquinone aromatic compounds capable of solubilizing tetravalent vanadium. The absorbed hydrogen sulfide is converted to elemental sulfur which, after oxidative regeneration of the washing solution, is separated from the regenerated solution.

Abstract: Hydrogen sulfide is removed from a gaseous stream by contacting the stream with an aqueous solution of ferric ion chelated with an aminopolycarboxylic acid at a pH of 3.5 to 5, whereby hydrogen sulfide is oxidized to elemental sulfur and chelated ferric ion is reduced to chelated ferrous ion. The solution also contains ammonia or an aliphatic, alicyclic, or heterocyclic primary or secondary amine in a sufficient proportion to maintain chelated ferrous ion in solution at a pH of 3.5 to 5. The chelated ferric ion is regenerated by contacting the solution with a gas containing elemental oxygen.

Abstract: An aqueous solution of a zinc salt is used to selectively remove hydrogen sulfide from a gas mixture. An insoluble basic zinc compound is added to the solution to regenerate, or replenish, the salt. A dispersant is added to both decrease the surface tension of the liquid and reduce the degree of hydration of the basic compound, thereby retarding significantly the agglomeration, settling and loss of the basic zinc compound.

Abstract: Process for the work-up of hydrogen-sulfide containing gases which are normally subjected to Claus process, reduction, absorption, and desorption, characterized in that a portion of the feed gases by-passes the Claus unit and is processed in a CO.sub.2 -selective secondary absorption-desorption procedure.

Abstract: In the Stretford process wherein hydrogen sulfide, obtained for example, in the catalytic conversion of sulfur compounds, is absorbed into an alkaline solution of the sodium salt of anthraquinone disulfonic acid (ADA) and sodium vanadate and eventually converted to elemental sulfur by a reaction of the sodium vanadate with the hydrogen sulfide, some of the hydrogen sulfide undergoes side reactions and is converted to undesirable by-products, e.g., sodium sulfate and sodium thiosulfate. These by-products were removed in the prior art by burning; however, the expensive salts of ADA were also burned in the process of the prior art. In the present improvement, the sodium salts of ADA are preferentially removed in an adsorption column filled with a macroporous adsorption resin, prior to the combustion stage. The adsorption column can be regenerated either with water or with an aqueous solution of sodium carbonate formed in the combustion stage.