Abstract: A method and apparatus for the hydrothermal treatment of a catalytic polyvalent metal redox absorption solution, after absorption of the H.sub.2 S from an H.sub.2 S containing gas stream, to avoid substantial buildup of thiosulfate salts, cyanide salts, and cyanide complexes in the catalytic polyvalent metal redox solution. The method and apparatus of the present invention is particularly useful for treating gas streams containing both H.sub.2 S and HCN concurrently for destruction of the cyanide salts and cyanide complexes and conversion of H.sub.2 S and by-product salts to elemental sulfur.

Abstract: A process is disclosed for the separation of hydrogen cyanide from gases and waste gases by a throughflow or circulation scrubbing, in which formaldehyde is added at a controlled rate to the aqueous scrubbing liquid to form glycol nitrile. This addition is controlled by measuring the HCN tension in a measuring stream which has been branched off and which is first treated with hydrogen peroxide so that free H.sub.2 O.sub.2 is still detectable after 1 to 100 seconds and the pH is adjusted to a constant value before measurement of the HCN tension is carried out. The process prevents overdosing with formaldehyde which could not always be prevented in previously known processes in which the addition of formaldehyde was regulated by measuring the cyanide specific redox potential.

Abstract: Activated charcoal, or ASC whetlerite charcoal for use in providing protection against chemical warfare agents, contains chromium VI, which is a known carcinogen, as well as other metal impregnants. Thus disposal of the charcoal can present problems. The charcoal is usually impregnated with the chromium and other active metals by placing the charcoal in a solution of the metals, and oven drying the charcoal so that crystals are deposited thereon. It has been found that if the charcoal is freeze-dried the quantity of the metals such as chromium VI can be reduced by as much as 50% without compromising the performance of the charcoal.

Abstract: A flue gas that contains small amounts of both HCN and NO.sub.x, produced, for example, by catalyst regeneration in the fluid catalytic cracking of a petroleum gas oil, is readily denitrified by the catalyzed reaction that proceeds approximately according to:HCN+NO.fwdarw.N.sub.2 (gas)+CO+CO.sub.2 +H.sub.2 OIf the molar ratio of HCN to NO in the flue gas is about 1.0, e.g. in the range of about 0.8 to 1.2, effective denitrification is achieved without first changing the composition of the flue gas by contacting it with catalyst under conversion conditions including elevated temperature. If the molar ratio of HCN to NO exceeds 1.2, the ratio may be adjusted to about 1.0 to 1.1 by thermal or catalytic oxidation in the presence of oxygen gas, followed by catalytic denitrification. If the molar ratio is less than about 0.8, the effective molar ratio is adjusted to about 1.0 to 1.1 by adding NH.sub.3 gas, followed by denitirification.

Abstract: A method and apparatus for treating a catalytic polyvalent metal redox absorption solution, after absorption of H.sub.2 S from a gas, in a first hydrothermal treatment, to separate the polyvalent metal, for example as a polyvalent metal sulfide precipitate, and thereafter treating the redox solution in a higher temperature hydrothermal treatment to decompose thiosulfate salts and, if present, thiocyanide and other cyanide salts and metal-cyanide complexes to decompose the salts and complexes to molecules that can be treated in the H.sub.2 S-absorption process for recovery of sulfur and alkali values.

Abstract: Whetlerite degraded by exposure to atmospheric contaminants is treated to restore its ability to adsorb toxic air pollutants by passing through it a flow of an oxygen-containing gas further containing from 500 to 2000 ppm of carbon monoxide and water vapor corresponding to 60 to 90 percent relative humidity at 60 to 80 degrees C.

Abstract: Activated carbon is used on gas-mask canisters for filtering air to remove toxic vapors. For military use, the charcoal is impregnated with inorganic salts or organic compounds for improving the chemical activity of the charcoal with respect to toxic vapors having low boiling points and small molecular sizes, e.g. cyanogen chloride. One such compound, namely triethylenediamine (TEDA) has been added to charcoal by sublimation at atmospheric pressure. A more effective method of impregnating charcoal with TEDA utilizes reduced pressure 0.13 to 13 Pa, preferably 1.3 Pa as a driving force to facilitate vaporization of the TEDA by sublimation. The activated carbon to be impregnated is dried at 110.degree. C. to 160.degree. C. for three hours and transferred to a vacuum desiccator. The required amount of the amine, namely 1.57 to 12.57%, preferably 4.7% is placed in the container on top of the activated carbon and the container is evacuated to a pressure of about 1.3 Pa and heated at 40.degree. C.

Abstract: A process for the treatment of a gas stream derived from the gasification of coal is described, the process being characterized, in one embodimment, by stripping of the wash and cooling liquid used to cool and remove NH.sub.3 from the synthesis gas prior to reuse of the liquid in removal of residual solids from the product gas stream, thereby avoiding incompatibilities which may initiate or aggravate chemical precipitation, particularly that of CaCO.sub.3.

Abstract: A method for making a substantially flexible dry matrix and the result and article capable of cleaning a surface by removing dust and/or organic film and rendering the surface substantially static-free, suitable for use as a garment, air filter or mat, comprising a matrix comprising natural or synthetic, woven, non-woven or knitted fibers, or a flexible foam material, said matrix having been uniformly coated with an amount of treatment solution sufficient to allow said matrix to retain its substantially dry characteristics, said solution comprising between about 25% and 75% of at least one glycol compound, between about 0.2% and 60% of a cationic surfactant, an antimicrobial compound and optionally up to about 45% of a nonionic surfactant may be added to the treatment solution. When removing organic film, the wipe is contacted with water and used to wash the surface, and can then be rung out and used to wipe the surface dry.

Abstract: Process for the removal of isocyanic acid from a gaseous mixture of isocyanic acid and ammonia by introducing a tertiary amine or ether at 250.degree. to 600.degree. C. The gaseous reaction mixture is passed into an inert diluent and cooled, to condense an adduct of isocyanic acid and tertiary amine or ether, and the ammonia being removed as a gas.

Abstract: Impregnated activated carbon adsorbents for the removal of toxic materials from gas streams are used in a variety of respiration and collective filter applications. The activated carbon impregnated adsorbents in the present invention remain effective in removing toxic gases and/or vapors in military, industrial and other applications, and are free of chromium and its potential health hazards. Generally, these activated carbons are comprised of an activated carbon adsorbent impregnated so as to result in an activated carbon containing 0 to 14% copper and 2 to 16% zinc, optionally supplemented according to the desired characteristics with silver, triethylenediamine, and prepared with or without the use of organic acid. The adsorbent carbons of the present invention have been found to be effective for removing a variety of toxic gases and/or vapors.

Abstract: Air contaminated with chemical and biological pollutants is purified by treating chemically and electrochemically in a closed system minimizing the generation of by-products for disposal. Pollutants are treated in a scrubber zone with a scrubber liquid-electrolyte comprising pollutant degrading metal ions or complexed with inert metal ions and degraded either in an electrolyzer zone or in both the scrubber and electrolyzer zones where spent scrubber liquid-electrolyte is regenerated for further cleaning.

Abstract: HCN and H.sub.2 S, are removed from a gas stream containing same by:(a) contacting in the presence of a base in a first contactor at an elevated temperature the gas stream with a first aqueous solution containing dissolved sulfur in order to obtain a purified gas mixture and a second aqueous solution containing reaction products of the base and the sour components;(b) cooling the purified gas mixture to a temperature beneath the melting point of sulfur;(c) contacting in a second contactor the purified gas mixture with an aqueous reactant solution containing an effective amount of oxidant under conditions to oxidize H.sub.

Abstract: The present invention is a process for reversibly absorbing acid gases, such as CO.sub.2, H.sub.2 S, SO.sub.2, HCN and the like from gas mixtures. The gas mixture containing one or more of these acid gases is contacted with a hydrated salt of the compositionA.sub.x.sup.m+ B.sub.y.sup.n-.rH.sub.2 Owherein A.sup.m+ is a cation, B.sup.n- is the conjugate base of a weak acid having a pKa corresponding to an ionization constant of the acid greater than 3 as measured in dilute aqueous solution, m and n are independently integers from 1-4, x and y are integers such that the ratio of x to y provides a neutral salt and r is any number greater than zero up to the maximum number of moles of water which can be bound to the salt. The salt hydrate reversibly absorbs the acid gas from the gas mixture.

Abstract: There is here disclosed a method for removing nitrous oxide (N.sub.2 O), carbon dioxide (CO.sub.2) and dinitrogen difluoride (N.sub.2 F.sub.2) from a nitrogen trifluoride gas. The present invention is directed to a method for purifying a nitrogen trifluoride gas which comprises the steps of thermally treating, at a temperature of 250.degree. to 700.degree. C., a zeolite selected from the group consisting of analcime, clinoptilolite, mordenite, ferrierite, phillipsite, chabazite, erionite and laumotite; forming a packed bed of the treated zeolite; and passing the nitrogen trifluoride gas containing the gaseous impurities at a temperature of -125.degree. to 50.degree. C. through the filler layer.

Abstract: Disclosed are primary sterically hindered aminoacids for use as promoters for alkali metal salts in acid gas scrubbing. The primary sterically hindered aminoacid is selected from 1-amino-cyclopentane carboxylic acid and those represented by the formula: ##STR1## where R.sub.1 and R.sub.2 are independently selected from CH.sub.3, C.sub.2 H.sub.5, and C.sub.3 H.sub.7 ; R.sub.3 and R.sub.4 are independently selected from hydrogen and CH.sub.3 ; and n is 0, 2, or 3.

Abstract: Process for selective removal and destruction of hydrogen cyanide contained in nitrous gases, in which the nitrous-containing gases are washed with nitric acid in counter-current in an absorption column and the nitric acid charged with hydrogen cyanide is regenerated at elevated temperature, with simultaneous hydrolysis and oxidation of the hydrogen cyanide.

Abstract: Cyanogen halides and/or phosgene are removed from waste gases by bringing the waste gases into intimate contact with an aqueous solution of at least one amine of the formula NR.sub.3 ; in the formula, 1 or 2 of the radicals R represent an alkanol or alkylamine group having 2 or 3 carbon atoms in each case, where H and/or C.sub.1 -C.sub.2 -alkyl is bound to the nitrogen of the amine group, and the remaining groups R are H or C.sub.1 -C.sub.4 -alkyl.

Abstract: A control system is provided for a mist scrubbing process in which a gas containing odorous and acidic contaminants is cocurrently contacted in a reaction chamber with tiny droplets of an aqueous reagent to react with and destroy the contaminants. The reagent contains an oxidizing agent and a base and the process is controlled by measuring a property, typically pH, of spent spray liquid settling at the bottom of the chamber. That measurement is used to meter the flow rate of base into the system while at the same time the concentration of an acidic contaminant in the scrubbed gas stream leaving the reaction chamber is measured and that measurement is used to meter the injection rate of an oxidizing agent into the system.

Abstract: A process for decomposing ammonium thiocyanate and equivalent compounds comprising mixing the compounds with molten ammonium sulfate at atmospheric pressure and about 310.degree. C. The compounds decompose giving off carbon dioxide, sulfur dioxide, ammonia and sulfur and leave a residue of ammonia salts but no organic materials.

Abstract: HCN, and HCN along with COS may be removed from gaseous streams, particularly those derived from the gasification of coal, by contacting the gas stream with a catalyst consisting essentially of specified amounts of molybdenum oxide, or precursor or precursors thereof, and alumina.

Abstract: Cyanogen chloride is removed from air or other gases using a whetlerite type filter which omits chromium and comprises an activated carbon base impregnated with triethylenediamine and optionally copper and silver.

Abstract: A chromium free absorbent filter material and method for removing toxic gases such as cyanogen chloride, cyanogen and hydrogen cyanide is disclosed. The filter material is a whetlerite type activated carbon impregnated with copper, silver, and molybdenum and/or vanadium salts together with triethylenediamine and essentially retains the effectiveness of similar chromium containing whetlerites for protection without the carcinogenic hazard presented by chromium. The new material also releases substantially less ammonia odor compared to the conventional chromium bearing whetlerite.

Abstract: A process for removing HCN from gases, which may also contain a hydrogen halide, by hydrolysis in the presence of a supported metal from Group 3b and/or 4b, use being made of a silica-containing carrier or support.

Abstract: The present invention provides a gel having excellent separation ability, operability and a long life, for separating useful components from a rhodanate-containing detoxication treated liquid. The gel consists of a cross-linked polymer with more than 50 weight % of repeating units which are composed of 2,3-dioxypropyl (meth)acrylate or 2,3-dioxypropyl (meth)allyl ether, and whose average particle diameter is more than 10.mu. and gel water content is from 30 to 150%. The present invention also provides a method of separation using said gel.

Abstract: In purifying gas wash waters containing cyanide with formaldehyde, the exact dosing of formaldehyde presents a problem, especially with strongly fluctuating cyanide contents. By continuous potentiometric measurement in a side stream which is regulated to a pH of 7 to 10, while the pH of the main stream remains unchanged, the formaldehyde can be adjusted safely to any cyanide content.

Abstract: A process for the management of by-product tetranitromethane (TNM) which avoids the hazards of the prior art isolation or extraction procedures. A selected in-plant liquid or vapor stream, or a reactor off-gas stream from nitration or nitric acid oxidation plant, which contains TNM, is heated to effectively pyrolyze the TNM without undue losses of nitric acid values.

Abstract: This process relates to the upgrading of at least one stream of condensate water by removing water soluble gaseous impurities from the group consisting of HCN, COS, HCOOH, and mixtures thereof as produced in a process for the production of synthesis gas by the partial oxidation of solid carbonaceous fuel and/or liquid hydrocarbonaceous fuel. In the process, at least one internally produced condensate stream of water containing the aforesaid water soluble gaseous impurities is mixed with and vaporized into a stream of synthesis gas. The vaporized mixture is then introduced into at least one bed of catalyst where the gaseous impurities are removed by hydrolysis. The upgraded water stream is then recycled in the process for use in cooling and/or scrubbing the hot raw effluent gas stream from a partial oxidation gas generator.

Abstract: A process for scrubbing a synthesis gas stream containing residual amounts of iron containing particulate solids and minor amounts of HCN is disclosed, the process being characterized by scrubbing of the synthesis gas with an aqueous reactant solution, and providing for conversion of any iron complex or iron complexes formed during scrubbing by a low temperature conversion step.

Abstract: A gaseous constituent such as SO.sub.2, HCl, or HF is removed from a gas stream in a granular bed filter containing granules coated with a sorbent material which is reactive with the gaseous constituent. Granules carrying reacted sorbent material are removed from the granular bed filter, cleaned of reacted sorbent material and coated with further sorbent material for reuse in the granular bed filter. Electrification of the filter bed permits simultaneous, highly efficient removal of particulates entrained in the gas stream.

Abstract: Process and catalyst for the selective catalytic hydrolysis of the inorganic sulfur compounds COS and/or CS.sub.2 being present in CO containing process gases. The process gas is passed over an alkalized chromium oxide-aluminum oxide catalyst in the presence of H.sub.2 O.

Abstract: A process for removal of iron cyanide complex or complexes from a solution is described, the process being characterized by contact of the solution containing the complex or complexes with ammonium polysulfide or sodium polysulfide, or a mixture thereof, at a temperature of from about 110.degree. C. to about 180.degree. C.

Abstract: A process for the removal of cyanide complex or complexes from synthesis gas streams also containing residual iron containing particulate matter is disclosed, the process being characterized by scrubbing of the synthesis gas stream with water or an aqueous stream, removal of absorbed HCN, if any, from solution used in scrubbing, and contact of substantially HCN-free scrubbing solution with a polysulfide reactant at temperatures of from 110.degree. C. to 180.degree. C.

Abstract: The ammonia, hydrogen cyanide, and hydrogen sulfide scrubbed out of crude coke oven gases are decomposed and combusted, and sulfur is recovered therefrom in a Claus process, while using preheated air and effecting the decomposition and oxidation at temperatures varying through 100.degree. C. at most, and keeping the temperature level of the entire process above 100.degree. C. and allowing the residual gases to cool below this temperature only after the separation of sulfur, and controlling the air supply to maintain the ratio of H.sub.2 S and SO.sub.2 in the process gases above 2.

Abstract: Methyl isocyanate in waste gaseous emissions is abated at temperatures substantially lower than those required in the conventional operation of a Process Thermal Oxidizer by contacting the waste gaseous emission with one or more transition metal oxide catalysts at a temperature of at least about 400.degree. C.

Abstract: HCN is removed from a gaseous stream, e.g., a synthesis gas stream, by a two stage procedure in which the gaseous stream is first contacted with a specified oxygenated reactant composition to remove the bulk of the HCN, and then the gaseous stream is contacted with a polysulfide solution to reduce further the HCN content of the stream.

Abstract: A process for the removal of acid gases which are reactive with ethylene oxide from a gas mixture containing carbon dioxide, comprises contacting the gas mixture with ethylene carbonate containing sufficient amount of ethylene oxide, whereby the ethylene oxide reacts chemically with the acid gases to produce reaction products which are more easily removable from the gas mixture.

Abstract: The present invention provides a filter for use in association with cigarette tobacco, wherein the filter contains, as active component, at least one non-toxic inorganic or organic salt of a compound of the general formula:H--S--X--SO.sub.3 Hin which X is a straight or branched alkylene radical containing 2 to 6 carbon atoms, and/or cysteine and/or acetylcysteine. The present invention also provides a cigarette and a cigarette holder comprising such a filter.

Abstract: The NH.sub.3 content is regulated in methanol used in a process for scrubbing out sour gases from gaseous mixtures and/or for preventing ice formation prior to the scrubbing step. The methanol is freed, after the scrubbing step, respectively of absorbed gaseous components and/or water, and reused in the cycle as scrubbing liquid and/or for preventing ice formation. A strong acid is added to the methanol from water-soluble ammonium salts. Thereby, dissolved salts are formed which are removed together with water. Deleterious trace acids are also removed by an analogous treatment with a basic compound. The acid/base treatments are conducted in succession.

Abstract: Ammonia and hydrogen sulfide are washed out of the coke oven gas and stripped from the wash liquor in the form of gases and fumes or vapors. The ammonia is decomposed in a nickel catalyzer and a small part of the decomposition gases is supplied directly to a combustion furnace, while the larger part of the combustion gases is first cooled and freed from condensate, and only then supplied to the combustion furnace. In the combustion furnace, the proportion of H.sub.2 S/SO.sub.2 needed for the Claus process is adjusted by a partial combustion of the decomposition gases. The gases from the combustion furnace are then processed in the Claus plant to sulfur.

Abstract: A process for the removal of HCN from gaseous streams is described, the process being characterized by reaction of the HCN in the gaseous stream with an ammonium polysulfide solution and formation of ammonium thiocyanate in solution, precipitation and removal of sulfur from the ammonium thiocyanate-containing solution, and hydrolysis of the ammonium thiocyanate. Provision is made for recycle of hydrolysis products.

Abstract: A process for the removal of HCN from gaseous streams is described, the process being characterized by reaction of the HCN in the gaseous stream with an ammonium polysulfide solution, formation of ammonium thiocyanate in solution, decomposition of ammonium polysulfide and precipitation of sulfur from the ammonium thiocyanate solution in a stripping zone, and hydrolysis of the ammonium thiocyanate. Recycle or recovery of sulfur and hydrolysis products are contemplated.

Abstract: A process for the removal of HCN from gaseous streams is described, the process being characterized by reaction of the HCN in the gaseous stream with an ammonium polysulfide solution, formation of ammonium thiocyanate, and hydrolysis of the ammonium thiocyanate. Recycle of hydrolysis products is contemplated.

Abstract: In the invention, cyanide-bearing gas scrubbing waters, which are produced in metallurgical processes, are cleaned. The same scrubbing water is circulated through all gas scrubbers (1, 3) essentially connected to the metallurgical process. The solid substance which is thus acquired in the scrubbing water is separated from the scrubbing water in a clarifier (4), wherefrom the extracted solid substance is conducted as pulp into the grinding circle of the process. The cyanide-bearing scrubbing water is further conducted into the cooling (9) of the material received from the metallurgical process smelting furnace. In the cooling (b 9), the major part of the cyanide is evaporized due to the rise in temperature.

Abstract: A process of separating in multiple stages acid components in coke oven gas such as CO.sub.2, HCN and particularly H.sub.2 S by ammonia scrubbing wherein the ammonia used in scrubbing is deacidified to remove the acid components and is recirculated to the scrubbing process at least in part as substantially pure liquid ammonia.

Abstract: Hydrogen sulfide and hydrogen cyanide are catalytically removed from air at room temperatures. Air containing H.sub.2 S and HCN in dilute concentrations is contacted with a dry, activated catalyst formed of palladium (II) and copper (II) salts such as chlorides, on an alumina substrate, at a temperature in the range of -20.degree. C. to 85.degree. C. The catalyst may also contain nickel (II) chloride.

Abstract: A gas purification system has: a first treatment apparatus, which purifies an untreated feed gas, containing toxic ingredients such as HCN gas, H.sub.2 S gas and NH.sub.3 gas, into a primary treated gas by causing the feed gas to contact with an alkaline absorbent liquid; an absorbent-liquid-resuscitation apparatus, which refreshes the absorbent liquid, after absorbing the toxic ingredients, by bubblingly introducing a resuscitation gas; and a second treatment apparatus, which further purifies the primary treated gas into a secondary treated gas by strippingly capturing any possible remnant NH.sub.3 gas still present in the former. The resuscitation gas and the toxic-ingredient-absorbed absorbent liquid are forcibly converged by premix nozzles into combined gas/liquid jets as are injected into the absorbent-liquid-resuscitation apparatus.

Abstract: A gas purification system has: a first treatment apparatus, which purifies an untreated feed gas, containing toxic ingredients such as HCN gas, H.sub.2 S gas and NH.sub.3 gas, into a primary treated gas by causing the feed gas to contact with an alkaline absorbent liquid; an absorbent-liquid-resuscitation apparatus, which refreshes the absorbent liquid, after absorbing the toxic ingredients, by bubblingly introducing a resuscitation gas; and a second treatment apparatus, which further purifies the primary treated gas into a secondary treated gas by strippingly capturing any possible remnant NH.sub.3 gas still present in the former. The resuscitation gas and the toxic-ingredient-absorbed absorbent liquid are forcibly converged by premix nozzles into combined gas/liquid jets as are injected into the absorbent-liquid-resuscitation apparatus.

Abstract: The reaction off-gas from the synthesis of melamine consists, after separating off the melamine, mainly of ammonia and carbon dioxide, with traces of hydrogen cyanide, isocyanic acid, urea and residual melamine. To remove these trace components, the off-gas is passed over a catalyst, containing copper oxide and/or iron oxide, in the presence of steam at from 100.degree. to 500.degree. C.

Abstract: An improved sulfur-ammonia process for removing hydrogen sulfide from coke oven gases. In the improved process, a concentrator formerly used for standby operation is used at all normal times as an ammonia scrubber to improve the efficiency of gas separation during normal operation and is used as a concentrator for its intended standby functions during the alternative operations. In its normal function, the concentrator/scrubber functions as a scrubber to strip ammonia gas from recirculating liquid streams and to permit introduction of an ammonia-rich gas into a hydrogen sulfide scrubber to increase the separation efficiency of that unit. In the standby operation, the same concentrator/scrubber serves as a concentrator to concentrate hydrogen sulfide in a "strong liquor" stream for separate recovery as a "strong liquor.