Abstract: In the Claus process for the production of sulfur a gas stream containing ammonia and hydrogen sulfide is treated to form a gas containing hydrogen sulfide and virtually no ammonia and a second gas which contains ammonia and is virtually free from hydrogen sulfide. The two gases are separately burned in the same Claus furnace with oxygen. To produce the gas virtually free from ammonia, a partial stream of the gas containing ammonia and hydrogen sulfide is scrubbed with water with the ammonia being recovered from the water.

Abstract: A process is provided for removing ammonia, hydrogen sulfide and hydrocyanic acid from gases such as coke oven gas. In carrying out the process, the gas to be cleaned is first washed with an alkaline solution to remove the hydrogen sulfide and hydrocyanic acid. The hydrogen sulfide is oxidized by air to produce elemental sulfur, which is removed, and the alkaline solution is recirculated for reuse, a portion of the solution carrying cyanide and other compounds being diverted for further treatment. The gas to be cleaned is subjected to a second washing operation with an inorganic acid solution which removes the ammonia from the gas by formation of an ammonia salt solution. The salt solution is regenerated to recover the acid which is recirculated for reuse.

Abstract: A process for the recovery of pure concentrated ammonia in which the gaseous products of coal gasification or degassing are condensed or are washed with water to produce a phenolic-containing liquid phase (gas water), this liquid is dephenolated by extraction with a solvent, the phenol is recovered from the solvent and the gas is driven from the liquid phase. The gas is washed with circulated phenol and residual solvent is eliminated therefrom after NH.sub.3 is removed by washing.

Abstract: A method is provided for removing ammonia from the sour water stream of a coal gasification process. The basic steps comprise stripping the ammonia from the sour water; heating the stripped ammonia to a temperature from between 400.degree. to 1,000.degree. F; passing the gaseous ammonia through a reactor containing a sulfided catalyst to produce elemental hydrogen and nitrogen; and scrubbing the reaction product to obtain an ammonia-free gas. The residual equilibrium ammonia produced by the reactor is recycled into the stripper. The ammonia-free gas may be advantageously treated in a Claus process to recover elemental sulfur. Iron sulfide or cobalt molybdenum sulfide catalysts are used.

Abstract: In the process disclosed, gas from a coke plant is washed with an aqueous metallic salt solution including sulfureous and sulfuric acid to absorb the ammonia, hydrogen sulfide and hydrogen cyanide from the gas. The washing solution is then oxidized in an aerating tank to recover elementary sulfur. A portion of the washing fluid from the oxidizer is returned for continued washing of gas and a portion of the fluid is heated in the presence of a catalyst to yield products of combustion including an acid anhydride and a metal or metal oxide. After processing the combustion products through a heat recovering system, the acid anhydride and metal oxides are combined and react to form renewed aqueous metal salt solution that is combined with the oxidized washing solution to wash additional quantities of gas.

Abstract: Vent gas containing disagreeable odor components consisting mainly of phenolic substances evolving from foundries using shell molding sand containing phenol resin as a binder is efficiently wet-treated by scrubbing the vent gas with an aqueous absorbent solution, to which a ferrous salt and hydrogen peroxide are added so that a ferrous ion concentration may be at least one-seventh of a hydrogen peroxide concentration, thereby making an oxidation-reduction potential of the aqueous absorbent solution have at least a value of (540 - 60 .times. PH value) mV, wherein the PH value is 5 or less.

Abstract: A continuous process is provided which has the primary purpose of removing NH.sub.3, H.sub.2 S, HCN, and (CN).sub.2 from the subject gas mixtures and the secondary purpose of producing (NH.sub.4).sub.2 SO.sub.4 and iron oxide for industrial uses. The gas mixture which contains tar and other condensible vapors, NH.sub.3, H.sub.2 S, HCN, and (CN).sub.2 together with small volumes of gas from the ammonia still of the system, and gas from a system H.sub.2 SO.sub.4 plant, is contacted in a single three-stage reaction chamber in the presence, if need be, of a tar solvent, additional NH.sub.3, and the reagent Fe(OH).sub.2, which itself is a product of a concurrent reaction between NH.sub.3 and FeSO.sub.4. The unpurified gas mixture's condensible vapors are largely prevented from condensing by maintaining a steady, elevated temperature, while the mixture is essentially freed of HCN, (CN).sub.2, NH.sub.3, and H.sub.2 S in the reactor before the gas mixture passes through a primary gas cooler.

Abstract: Vapor mixtures containing ammonia, acid gases and water are contacted with aqueous ammonium phosphate solution to separate the ammonia from the acid gases and to permit recovery of the acid gases. This treatment may be performed on vapor mixtures obtained by steam stripping liquids containing ammonia and acid gases.

Abstract: A method and apparatus for stripping ammonia from an alkaline regenerant solution used for the regeneration of a zeolite ion exchange bed. The regenerant passes through a stripping column. An acidic working solution is circulated from a holding tank through a vacuum creating means and then back into the holding tank. The ammonia is stripped from the regenerant under a vacuum created in the stripping column by the vacuum creating means so as to cause the stripped ammonia to chemically react with working solution to form an ammonium salt solution. Carbon dioxide free air is passed upward through the column countercurrent to the flow of regenerant.

Abstract: Refinery or similar streams containing NH.sub.3 are processed in a sulfur plant having separate burners for the NH.sub.3 -containing acid gas stream and for the NH.sub.3 -free acid gas stream. A sampling device is provided for continuously or periodically sampling the combustion products from the unit burning the NH.sub.3 -containing gas. The H.sub.2 S/SO.sub.2 ratios at this sample point and in the sulfur plant tail gas are used to control the operation of the system.

Abstract: Ammonia, hydrogen cyanide and hydrogen sulfide contained in gas streams are separated from the gas streams by contacting the gas stream with an aqueous solution containing free oxygen for a time sufficient for the ammonia, hydrogen sulfide and hydrogen cyanide to react with the oxygen present to form ammonium thiocyanate and water for further treatment or disposal.One method of treatment is to thermally and catalytically convert for the ammonium thiocyanate to ammonia or nitrogen and hydrogen sulfide in the form of a second gas stream which is processed for recovery of any formed ammonia and the hydrogen sulfide.

Abstract: Coke oven gases are washed with an aqueous metallic salt solution of sulfuric acid or sulfurous acid to absorb ammonia, hydrogen sulfide and hydrogen cyanide. The washing solution is then oxidized to recover elementary sulfur. A portion of the oxidized washing fluid is returned for continued washing of gas and a portion of the washing fluid is diverted to a separater where solid compounds which include metal hydroxide and metal cyanide compounds are removed leaving ammonium sulfate solution. The ammonium sulfate solution is heated with combustion air and in a heating agent to produce combustion products including nitrogen, hydrogen and an acid anhydride. The solid compounds from separater are conducted as a aqueous suspension to a reaction vessel wherein, at elevated temperature and pressure, hydrolysis products are formed including free ammonia, metal hydroxide and formate salts.

Abstract: A catalytic amount of ammonia or ammonium compounds are utilized to prevent deterioration of alkanolamines employed in gas sweetening processes. The ammonia is added either to the sour gas or the absorbing solution and acts to suppress thiocyanate .[.formation.]. .Iadd.accumulation .Iaddend.during absorption.BACKGROUND OF THE INVENTION1. Field of the InventionThis invention relates to gas purification and more particularly to gas purification by the removal of acid gases from industrial gas in an absorption/desorption process.2. Prior ArtThe term "gas sweetening" pertains to gas purification processes in which acid gases, particularly sulfurous gases are removed from industrial gases.Gas sweetening processes commonly utilize aqueous absorbing solutions into which the acid gases are scrubbed (absorbed) to be later stripped (desorbed) for possible further treatment. Desorbing is accomplished by heating the spent solution to expel the acid gases.