Abstract: The proportion of chlorine dioxide to chlorine in aqueous solutions formed from gaseous mixtures of chlorine dioxide and chlorine is improved over conventional separation techniques. The gaseous product stream from a chlorine dioxide generator is scrubbed with an aqueous salt mixture containing an approximately stoichiometric quantity of sodium hydroxide, which reacts preferentially with the chlorine, yielding chlorine dioxide of high purity. The absorption system is operated under such conditions that the chlorine is converted to sodium chlorate and sodium chloride, which may then be recirculated to the chlorine dioxide generating system. The scrubbing salt solution is adjusted so as to produce an R-2 mixture upon reaction with the chlorine in the chlorine/chlorine dioxide stream.

Abstract: Molecular chlorine level in flue gases from incineration of chlorinated organic materials is reduced by injecting into the incinerator's quench zone an amount of a C.sub.1 -C.sub.4 hydrocarbon which depends on the amount of air fed into the combustion zone, the amount of air being such that there is a 1-40 % excess of oxygen. When the wall temperature of the combustion zone is about 800.degree.-1500.degree. C., the temperature at which the hydrocarbon is added to the quench zone is about 450.degree.-1000.degree. C. Hydrogen chloride, which is formed from molecular chlorine and hydrocarbon, is more readily water-scrubbed than chlorine, so that less polluting flue gases are obtained.

Abstract: Gas streams contaminated with acid and acid precursor gases and vapors are purified by contacting the gas streams with activated carbon impregnated with sodium hydroxide.

Abstract: A process for treatment of aluminum chloride production offgas containing Cl.sub.2, CO, CO.sub.2, HCl, COCl.sub.2, COS, SO.sub.2, N.sub.2, SiCl.sub.4 and metal chlorides by reaction with water vapor in the presence of an alumina or low iron sand catalyst to convert SiCl.sub.4 and metal chlorides to the corresponding oxides and HCl; subsequent reaction of COCl.sub.2 with water vapor in the presence of an activated carbon catalyst to form CO.sub.2 and HCl; and removal of HCl by contacting the offgas with liquid water. Reaction with steam in the presence of alumina catalyst prior to reaction with steam in the presence of an activated carbon catalyst prolongs the useful life of the activated carbon catalyst and avoids the necessity of removing SiCl.sub.4 and metal chlorides from the offgas by adsorption onto dry activated carbon prior to contacting the activated carbon catalyst with offgas.

Abstract: Waste gases are purged by adding to the gas while it flows through an abser a neutralizing agent together with water and then subjecting the gas to cooling so as to evaporate the added liquid. The adsorption then results in a reaction with the neutralizing agent whereby dry salts are formed which are removed from the process. The temperature of the waste gas is automatically and continuously measured and the volume of the water is adjusted automatically and continously in accordance with the temperature measurements. The amount of waste gases is furthermore automatically and continuously measured, preferably at several places of the process, and the amount of neutralizing agent is continuously and automatically adjusted to the latter measurements so as to obtain always the stoichiometric equivalent for the reaction with the pollutants.

Abstract: A waste flue gas cleaning method and an apparatus for practicing said method, in which a reactant solution is sprayed into a waste flue gas introduced into a spray tower, whereby a toxic component in the flue gas is caused to be absorbed in and react with the droplets of the sprayed reactant solution, and the water contained in the droplets is vaporized and the reaction products are dried into solid particles by the sensible heat of said flue gas. A series of the above operation is accomplished within the spray tower while maintaining the outlet gas temperature always above the dew point of the flue gas, and the solid particles of the reaction products are removed from the flue gas by an after dust collector.

Abstract: Halogenated hydrocarbon materials are burned in an internally-fired horizontal fire-tube boiler and the heat of combustion directly produces saturated steam. Halogen values may be recovered from the combustion gases, e.g., by being absorbed in water. Thus halogenated hydrocarbon material which may need to be disposed of, is beneficially converted to energy and useful product.

Abstract: Product yields are increased and effluent streams purified for disposal by an improved process for producing vanadium chlorides. The process comprises reacting vanadium oxide with chlorine and reactant carbon to produce substantially pure vanadium chlorides and an effluent stream containing vanadium chlorides and unreacted chlorine. The effluent stream is contacted with adsorptive carbon whereby the vanadium chlorides and chlorine are adsorbed thereon. The adsorptive carbon is subsequently recycled and used as the reactant carbon.

Abstract: This invention is a method for rapidly and continuously immobilizing carbon dioxide contained in various industrial off-gas streams, the carbon dioxide being immobilized as dry, stable, and substantially water-insoluble particulates. Briefly, the method comprises passing the gas stream through a fixed or fluidized bed of hydrated barium hydroxide to remove and immobilize the carbon dioxide by converting the bed to barium carbonate. The method has several important advantages: it can be conducted effectively at ambient temperature; it provides a very rapid reaction rate over a wide range of carbon dioxide concentrations; it provides high decontamination factors; and it has a high capacity for carbon dioxide.The invention is especially well suited for the removal of radioactive carbon dioxide from off-gases generated by nuclear-fuel reprocessing facilities and nuclear power plants.

Abstract: This invention relates to a process of removing chlorine (Cl.sub.2) and hydrogen chloride (HCl) from a combustion gas, such as a combustion gas formed from incinerating chlorine-containing organic materials, which comprises:(1) Lowering the temperature of the combustion gas below the melting point of cupric chloride or mixture thereof with other salts;(2) Contacting the cooled combustion gas of step (1), in the presence of oxygen, with copper of lower than a divalent oxidation state, such as a cuprous compound or its equivalent in a quantity sufficient to absorb chlorine and hydrogen chloride present in gas, thereby converting the cuprous compound to cupric chloride (in order to absorb substantially all HCl and Cl.sub.

Abstract: An improved method of removing bromine from fluid streams comprises contacting the fluid stream with an aqueous solution of certain asymmetrical quaternary ammonium bromides whereby a liquid, water immiscible bromine complex is formed that can be stored, manipulated and readily handled and which complex can be dissociated to liberate molecular bromine.

Abstract: Hydrochloric acid having a substantially constant HCl content of 20 to 36% is produced continuously by removing hydrogen chloride from hot combustion gas. To this end, hot combustion gas containing 1 to 10% by volume of HCl and steam, this gas being obtained by the joint combustion of off-gases containing chlorinated hydrocarbons and liquid residues of chlorinated hydrocarbons, is introduced into a quenching zone, and quenched therein, down to a temperature lower than its dew point, by means of cooled hydrochloric acid containing hydrogen chloride in a concentration of 20 to 36%, which concentration corresponds to the concentration of the hydrochloric acid which is to be produced. The resulting gas-liquid mixture is separated in an absorption cooling zone into cooled hydrochloric acid and cooled combustion gas containing 0.1 to 1% by volume of HCl.

Abstract: Pollutants such as NO.sub.x, SO.sub.x, and/or halogen gases are removed from gas streams containing such pollutants by contacting and reacting the gas stream with an aqueous medium containing an activated form of aluminum, i.e., high purity aluminum which has been activated by permeation with a second metal selected from mercury, gallium, and indium/gallium alloys. After passing the gas stream rich in the pollutant through the aqueous medium, a gas stream is removed which is leaner in the pollutant.

Abstract: Fission product iodine is removed from a waste gas stream and stored by passing the gas stream through a bed of silver-exchanged zeolite until the zeolite is loaded with iodine, passing dry hydrogen gas through the bed to remove the iodine and regenerate the bed, and passing the hydrogen stream containing the hydrogen iodide thus formed through a lead-exchanged zeolite which adsorbs the radioactive iodine from the gas stream and permanently storing the lead-exchanged zeolite loaded with radioactive iodine.

Abstract: A vent gas containing radioactive iodine and methyliodide is effectively decontaminated by chemically adsorbing the iodine contained in the vent gas onto an activated carbon layer at first, then physically adsorbing the methyl iodide contained in the vent gas onto another activated carbon layer separately disposed from the former activated carbon layer, and retaining the radioactive iodine and radioactive methyl iodide on the respective activated carbon layers for a definite period of radioactive decay.

Abstract: A molten mixture containing the higher and lower valent forms of a multivalent metal chloride; in particular, cuprous and cupric chloride, is contacted with oxygen, and aqueous hydrogen chloride recycle, to recover the chlorine values by generation of the higher valent metal chloride and also effect oxidation of the melt by production of the oxychloride. The gas withdrawn from the oxidation contains hydrogen chloride, chlorine and water vapor, with the hydrogen chloride being separate from the gas as aqueous hydrogen chloride and recycle to the oxidation. The chlorine and water vapor in the gas are contacted with activated carbon to produce hydrogen chloride, which is separated as aqueous hydrogen chloride and recycled to the oxidation.

Abstract: Gases are removed from enclosed spaces by (1) purging the space to be enclosed with a reactive gas such as carbon dioxide, (2) adding a metal hydrocarbyloxide and a solid absorbent for the volatile reaction products of the reactive gas and the metal hydrocarbyloxide, e.g., a solid absorbent such as activated charcoal, and (3) enclosing the space, e.g., by hermetically sealing the container. This method for gas removal is particularly useful in the production of thermal insulating articles such as double walled vacuum containers for storage of foods and beverages.

Abstract: A method and apparatus for removal of acidic gases from a gas stream by contacting the gas stream with an amine vapor in a reaction zone. The partial pressure of amine vapor in the reaction zone is at least 5 percent of the total pressure therein, resulting in removal of at least 99 percent of the acidic gases. When operating at ambient temperature and substantially atmospheric pressure, preferred amines are methylamine and dimethylamine.

Abstract: A process fluid is purified of strongly acidic impurities, preparatory to treatment over a catalyst or over a hydrogen sulphide absorbing material, by contact with one or more alkali metal aluminates, preferably a beta alumi aluminate. Such aluminates have a high capacity for absorbing hydrogen halides. The process fluid is especially a naphtha hydrocarbon to be reacted with steam to give a gas of high methane content.

Abstract: Certain anion exchange resins containing substantial amounts of cross-linker are useful in the removal of iodine and compounds thereof from gaseous effluents.