Abstract: A catalytic polyvalent metal redox solution can be recovered and re-used in a catalytic polyvalent metal redox solution H.sub.2 S-removal, sulfur production process by interposing a closed loop evaporator/condenser process and apparatus in the sulfur washing/filtering/recovery process and apparatus so that wash water used to purify the sulfur, and any polyvalent metal redox solution recovered from the sulfur melter are fed to an evaporator to concentrate the redox solution to a concentration capable of effective absorption of H.sub.2 S, and the water evaporated in the evaporator is condensed as pure water for use in washing and/or filtering the recovered sulfur.

Abstract: A catalyst composition useful in the catalytic oxidation of mercaptans is disclosed. The composition is a stable aqueous slurry or suspension of a first component which is predominantly a metal phthalocyanine disulfonate compound, and a second component which is predominantly a tetrasulfonated metal phthalocyanine compound.

Abstract: A catalyst composition useful in the catalytic oxidation of mercaptans is disclosed. The composition is a stable aqueous slurry or suspension of a first component which is predominantly a metal phthalocyanine disulfonate compound, and a second component which is predominantly a tetrasulfonated metal phthalocyanine compound.

Abstract: Solids plugging problems are often encountered during liquid-gas containing operations using a packed tower contactor. The invention alleviates or avoids such problems by providing a novel packing support grid characterized by a large total open area and large individual openings. The grid comprises vertically spaced upper and lower sets of laterally spaced bars. The vertical and lateral spacings are selected with respect to the size of the packing elements so that the packing elements cannot drop through the grid but at the same time the total open area of the grid is very large.

Abstract: Sour water is treated to remove dissolved hydrogen sulfide by means of an aqueous chelated polyvalent metal solution in a continuous recirculating system, particularly an autocirculation system, having reaction and oxygenation zones. The solution contains a small catalytic amount of chelated polyvalent metal, and the dissolved hydrogen sulfide is catalytically oxidized to sulfur in the liquid phase by means of dissolved oxygen in the solution. The sour water feed to the reaction zone is diluted by a massive recycle of oxygenated solution from the oxygenation zone before the sour water is contacted with air or other oxidizing gas used for oxygenating the used solution. A portion of the oxygenated solution containing chelated polyvalent metal is removed as the sweet water product, and replacement chelated polyvalent metal is added.

Abstract: Method and apparatus for recovering sulfur from an aqueous slurry. The slurry is passed downwardly through a shell-and-tube heat exchanger having vertically arranged tubes, wherein it is heated sufficiently to melt the sulfur. The liquid mixture leaving the heat exchanger is discharged into a first separation zone, in which a phase separation between the lighter aqueous phase and the denser liquid sulfur occurs. The upper aqueous phase is then transported to an intermediate point in the height of a vertically elongated second separation zone, while the molten sulfur is transported from the lower end of the first separation zone to a point adjacent the lower end of said second separation zone, in which an interface between the phases is maintained at a point below the entry point of the aqueous liquid phase into the second separation zone. The aqueous liquid is discharged from the top of the second separation zone, while molten sulfur is discharged from the bottom of said zone.

Abstract: In a cyclic hydrogen sulfide oxidation-catalyst regeneration process using an aqueous chelated polyvalent metal catalyst solution, excessive degradation of the aminopolycarboxylic acid chelating agent is prevented by incorporating in the solution an effective amount of a stabilizing agent capable of retarding or preventing rupture of nitrogen-carbon bonds in the chelating agent during oxidative regeneration of the catalyst solution. Alkaline thiosulfates are the preferred stabilizing agents. Particularly good results are obtained using an alkaline thiosulfate stabilizer in a catalyst solution comprising the dimer form of the NTA-iron complex.

Abstract: Apparatus for contacting a liquid reaction solution with a gas in separate reaction chambers within a single reaction vessel wherein the liquid reaction solution is continuously circulated between a first reaction chamber and a second reaction chamber within the reaction vessel but providing at least two side-by-side reaction chambers in open flow communication at their upper and lower ends with a gas supply means associated with each said chamber for introducing a gas in a finely divided form into the lower ends of each said chamber, and said gas supply means including flow control means whereby the rate of upward flow of gas in one of the chambers is greater than the rate of upward flow of gas in the other chamber so as to lower the density of the liquid reaction solution in the one chamber and provide continuous upward flow of liquid reaction solution and gas in the one chamber and downward flow of liquid reaction solution countercurrent to the flow of gas in the other chamber.

Abstract: An aqueous oxidation-reduction composition and method for removing hydrogen sulfide gas from a fluid stream by liquid phase oxidation of the hydrogen sulfide to elemental sulfur with a chelated polyvalent metal catalyst, such as iron, wherein the composition is stabilized against rapid loss of chelated polyvalent catalyst caused by contamination of the aqueous composition with micro-organisms, such as bacteria. The aqueous composition is stabilized by incorporating in the aqueous composition and adding throughout the normal usage thereof a broad spectrum biocide in an amount which acts as a bacteriostat to prevent rapid growth of bacteria in the aqueous composition and when the bacteria concentration rises above about 1.times.10.sup.6 colonies per ml.

Abstract: Reduction of nitrogen oxide emissions from thermal incinerators is accomplished in installations for calcining solid carbonaceous materials such as petroleum coke and anthracite coal. A hot effluent gas stream containing hydrocarbon vapors and entrained carbonaceous solid particles is removed from the calciner, and means are provided to effect preliminary combustion of the hydrocarbon vapors but not the carbonaceous solid particles in the gas stream using substantially the stoichiometric amount of combustion air. The resultant gas that is substantially free of hydrocarbons and oxygen is introduced into the thermal incinerator, and combustion of the carbonaceous solid particles is effected with additional combustion air.