Abstract: The invention describes a method of preparing magnetic ferrites from layered precursors in which Fe2+ is first introduced into the layers of layered double hydroxides (LDHs) in order to prepare Me-Fe2+—Fe3+ LDHs, and then by utilizing the easily oxidized nature of Fe2+, binary or multi-component ferrite materials containing Fe3+ in a single crystalline phase can be prepared. Values of the saturation magnetization of ferrites prepared by the method are significantly increased compared with ferrites prepared by traditional methods. Because the metal elements in the layered precursor have the characteristics of a high degree of dispersion, high activity and small particle size (average particle size 40-200 nm), no milling is required before calcination, thus simplifying the production process, shortening the production period, reducing capital investment in equipment and economizing on energy costs. In addition, the method does not corrode production equipment and does not pollute the environment.

Abstract: A process is provided for the combustion of ammonium salts of sulfuric acid contained in aqueous media. More particularly, a reductive combustion process which produces a combustion gas containing a divalent sulfur compound having a high concentration of hydrogen sulfide. The process is suitable for combusting ammonium salts of sulfuric acid produced during manufacture of 2-hydroxy-4-methylthiobutanoic acid (HMBA) or methionine. The divalent sulfur compounds in the combustion gas may be further converted to other useful sulfur products and recycled for use in the manufacture of HMBA or methionine.

Abstract: A two stage method is described for the removal of NOx and SOx from flue gas. The first stage removes all NOx by sodium sulfite sorbent injection. The second stage removes SOx by sodium bicarbonate injection. The sodium sulfite product formed in the second stage is transferred to the first stage for injection.

Abstract: Hydrogen sulfide is removed from gas streams by reaction with sulfur dioxide in an autogeneously-formed aqueous acid medium according to the equation: SO.sub.2 +2H.sub.2 S.fwdarw.2H.sub.2 O+3S the sulfur being removed from the aqueous phase. Carbonyl sulfide and/or carbon disulfide is removed from gas streams by hydrolysis to hydrogen sulfide in the presence of a weak organic base catalyst, such as quinoline, with the hydrogen sulfide reacting with sulfur dioxide to form sulfur.

Abstract: Methods for adsorbing toxic target chemical compounds such as HCN, P(O)(OCH.sub.2 CH.sub.3)(CN)(N(CH.sub.3).sub.2), ClCN, (CF.sub.3).sub.2 C.dbd.CF.sub.2, Zn(CH.sub.2 CH.sub.3).sub.2, Hg(CH.sub.3).sub.2, Fe(CO).sub.5, (P)(O)(CH.sub.3)(F)[OCH(CH.sub.3).sub.2 ], S(CH.sub.2 CH.sub.2 Cl).sub.2, C.sub.6 H.sub.5 C(O)CH.sub.2 Cl, C(O)Cl.sub.2, C.sub.6 Cl.sub.5 OH, C.sub.6 H.sub.3 (OH)(NO.sub.2).sub.3, C.sub.6 H.sub.5 (Br)(CN), C.sub.6 H.sub.5 CH.sub.2 CN and (CF.sub.3)C.dbd.CF.sub.2 are provided wherein such compounds (either as gases, liquids or solids) are contacted with nanoscale oxide adsorbents, such as MgO and CaO, preferably at a temperature in the range of -70 to 90.degree. C. and at atmospheric pressure. The preferred adsorbents have an average particle size of from about 1-20 nm, and have a total pore volume of at least about 0.5 cc/g.

Abstract: A catalytic combustion process for at least one fuel comprises the use of a plurality of successive catalytic zones, the process being characterized in that at least one of the first catalytic zones includes a catalyst comprising a monolithic substrate, a porous support based on a refractory inorganic oxide and an active phase constituted by cerium, iron and optionally zirconium, also at least one metal selected from the group formed by palladium and platinum; and in that at least one of the subsequent catalytic zones includes an active phase comprising: an oxide of at least one element A with valency X selected from the group formed by barium, strontium and rare-earths; at least one element B with valency Y selected from the group formed by Mn, Co and Fe; and at least one element C selected from the group formed by Mg and Zn, and aluminium; the oxide may have formula A.sub.1-x B.sub.y C.sub.z Al.sub.12-y-z O.sub.19-.delta., x being 0 to 0.25, y being 0.5 to 3; and z being 0.

Abstract: A method of controlling the oxidation of sulfites in a flue gas desulfurization process involves treating the exhaust gas with an absorbing fluid containing a calcium compound and controlling the oxidation of sulfites by regulating oxygen flow into the absorbing fluid. Oxygen flow is controlled by continuously monitoring the oxidation-reduction potential (ORP) of the absorbing fluid relative to the same fluid in a completely oxidized state using a detector with a plurality of fluid tanks, one of which functions as a reference tank at any particular time. The fully oxidized reference tank is periodically switched, reducing adherence of oxidizing substances to the ORP electrodes, resulting in more accurate measurements and reduced chemical oxygen demand of the waste water.

Abstract: A system for the abatement of industrial process emissions comprises a horizontal regenerative catalytic oxidizer (RCO). The system utilizes at least two regenerative chambers and at least two catalytic chambers in a controlled abatement process. Pollutants injected into the RCO from the process emissions are catalytically oxidized. The horizontal configuration of the RCO reduces the size of the RCO per cubic foot of emissions treated, and also simplifies maintenance requirements in removing and replacing, or regenerating, the catalyst. Chutes and valves situated above and below the catalyst provide maintenance means without the associated contamination concerns typically caused by catalytic migration throughout vertically configured RCOs.

Abstract: A method is disclosed for treating sulfur containing waste streams, comprising:a) injecting said sulfur containing waste streams into a sulfuric acid regeneration unit so as to produce a sulfur dioxide containing effluent;b) passing a portion of said sulfur dioxide containing effluent to a Claus thermal reactor, andc) diverting a portion of said portion of said sulfur dioxide containing effluent of step b to a Claus catalytic reactor that is downstream from said Claus thermal reactor in an amount sufficient to maintain the average temperature in the Claus thermal reactor to be less than 3,250.degree. F.

Abstract: With sufficient oxygen but with no added fuel gas, recovering sulfur from a gas stream containing hydrogen sulfide by oxidizing the gas stream with heat exchange from heat generated in a thermal converter section of a sulfur recovery unit to convert the hydrogen sulfide in the gas stream to sulfur oxide, and thus form a sulfur oxide enriched gas stream. The sulfur oxide enriched gas stream is contacted with a solid adsorbent bed to extract the sulfur oxides and retain them as sulfur compounds, thus forming a sulfur oxide depleted gas stream. The adsorbent bed is then contacted with a reducing gas stream to reduce the retained sulfur compounds to hydrogen sulfide and/or sulfur dioxide and thereby form a hydrogen sulfide and/or sulfur dioxide bearing stream. Sulfur is recovered from the hydrogen sulfide and/or sulfur dioxide bearing stream, and the sulfur oxide depleted gas stream maybe sent to an incinerator or vented through a stack.

Abstract: A part of the hydrogen sulphide content of a feed gas stream comprising hydrogen sulphide is burned by a burner that fires into a furnace. The combustion is supported by a stream of oxygen or oxygen-enriched air. Resulting sulphur dioxide reacts with residual hydrogen sulphide in the furnace to form sulphur vapor. Sulphur is condensed out of the resulting gas mixture in a sulphur condenser. At least part of the sulphur-free gas mixture flows through a reactor in which its sulphur dioxide content is reduced to hydrogen sulphide. Water vapor is removed from the resulting gas stream in a water condenser. At least part of the gas stream now essentially free of water vapor is recycled to the furnace. A purge stream is taken either from immediately downstream of the sulphur condenser or from intermediate the water condenser and the furnace, or from the furnace and, if desired, subjected to further treatment to remove sulphur-containing gases therefrom.

Abstract: A regenerative thermal oxidizer system is useful for treating a waste gas stream that contains volatile organic compounds. Two regenerators each contain heat exchange material that is arranged within the regenerators to recover heat generated by the oxidation of the volatile organic compounds. A first regenerator is in heating service and is used to preheat the waste gas stream before it enters an oxidation chamber where the volatile organic compounds are oxidized. From the oxidation chamber, the waste gas stream enters a second regenerator in cooling service where a portion of the heat generated by the oxidation reactions is recovered. When it is necessary to reverse the flow of waste gas through the regenerative thermal oxidizer, a trap for adsorbing volatile organic compounds is engaged.

Abstract: The invention relates to an alkanolamine composition for the removal of acid gas impurities comprising CO2, H2S, COS, or mixtures thereof, from a gaseous or liquefied gas stream containing said acid gases, and to a process of using the alkanolamine composition. The process involves contacting the gas stream with the alkanolamine composition, or an aqueous solution thereof, comprising a mixture of methyldiethanolamine (MDEA) and methylmonoethanolamine (MMEA) in an amount sufficient to generate in situ at least 5% by weight of N,N'-bis(dimethyl)-N-hydroxyethyl-ethylenediamine (DMHEED), in a contact zone, regenerating said amine composition in a regeneration zone, and recycling said regenerated amine composition to said contact zone. The invention also resides in an aqueous solution comprising from about 20% to about 70% by weight of DMHEED. The invention further resides in the addition of DMHEED in an amount of from about 5% to about 30% by weight to compositions or solutions containing other alkanolamines.