A method for preparing a molecular sieve SCR (selective catalytic reduction) catalyst and a prepared catalyst therethrough. In the method, several molecular sieves are mixed and modified by transition metal or rare-earth metal via ion exchange, then loaded Fe by equivalent-volume impregnation, and loaded Cu by one or more liquid ion exchange. This present invention, combined with several techniques, such as modification of stable molecular sieve by transition and rare-earth metal, Fe loading by equivalent-volume impregnation and Cu loading by one or more liquid ion exchange, and after through stable and effective modification and loading control, the obtained catalyst material is coated on a carrier substrate via size mixing and coating process to be prepared into an integral catalyst.

The invention relates to a method for treating metal strip in a directly fired furnace through which the metal strip is guided. The furnace is fired directly by gas burners and has a non-fired zone through which the exhaust gases from the fired zone flow and thus heat the metal strip. After leaving the non-fired zone, the exhaust gases from the furnace undergo post-combustion in an afterburner chamber. According to the invention, methane is injected into the non-fired zone, which causes nitrogen oxides contained in the waste gas to be converted into hydrogen cyanide.

The present invention relates to a method for producing automobile exhaust gas catalytic converters, to the catalytic converters as such and to the use thereof. In particular, the method comprises a step which results in a smaller particle size of the catalytically active material used.

A nitrous oxide (N.sub.2O) removal catalyst composition for treating an exhaust stream of an internal combustion engine is provided, containing a platinum group metal (PGM) component on a metal oxide-based support, wherein the N.sub.2O removal catalyst composition is in a substantially reduced form, such that it has an oxygen deficiency of about 0.05 mmol oxygen atoms/g or greater, and wherein the N.sub.2O removal catalyst composition provides effective removal of at least a portion of N.sub.2O from the exhaust stream under lean conditions at a temperature of about 350 C. or lower. N.sub.2O removal catalytic articles, systems, and methods are also provided for removing at least a portion of N.sub.2O from an exhaust stream under lean, low temperature conditions.

An apparatus is provided for treatment of process gas formed during nitric acid production by catalytic oxidation of NH.sub.3. The apparatus includes a reactor, a first catalyst bed for N.sub.2O decomposition, an absorption tower to react the NO.sub.x formed with an absorption medium downstream of the first catalyst bed, a device for adding NH.sub.3 added to tailgas entering the second catalyst bed, and a second catalyst bed for NO.sub.x reduction and further decrease in N.sub.2O in the tailgas exiting the absorption tower. The second catalyst bed contains at least one iron-loaded zeolite catalyst. N.sub.2O removal in the first catalyst bed is limited such that the process gas exiting the first catalyst bed exhibits a N.sub.2O content of >100 ppmv and a molar N.sub.2O/NO.sub.x ratio of >0.25. Treated gas exiting the second catalyst bed has a NO.sub.x concentration of <40 ppmv and a N.sub.2O concentration of <200 ppmv.

A catalyst for oxidation reaction of metallic mercury and reduction reaction of nitrogen oxide, comprising an oxide of titanium, an oxide of molybdenum, an oxide of vanadium, an oxide of phosphorus and gypsum is obtained by kneading titanium dioxide, ammonium molybdate, ammonium metavanadate, phosphoric acid, gypsum dihydrate and water using a kneader to obtain a paste, applying the paste to a metal lath substrate, and then drying and calcining the resultant.

A waste gas treatment method with the application of nano-bubbles and a waste gas treatment system using the same are provided. The method includes the steps of: feeding waste gas to an accommodating space; flowing a predetermined body of water in the accommodating space and generating the predetermined body of water including nano-bubbles; directing the waste gas mixed with the predetermined body of water including the nano-bubbles to a swirling unit; and discharging the treated gas waste. The predetermined body of water including the nano-bubbles is mixed with the waste gas so that the nano-bubbles of the predetermined water and the waste gas may be sufficiently subjected to the cavitation effect and supercritical water oxidation, and harmful substances such as sulfur dioxide, nitrogen monoxide and other nitrogen oxides, volatile organic compounds, heavy metals and the like, of the waste gas may be removed.

A process for removing a foulant from a gas stream. The gas stream is cooled in a series of heat exchangers, causing a portion of the foulant to desublimate and become entrained in a cryogenic liquid. This foulant slurry stream is pressurized, cooled, and separated into a pressurized foulant solid stream and the cryogenic liquid stream. The pressurized foulant solid stream is melted to produce a liquid foulant stream. Heat exchange processes, both internal and external, are provided that close the heat balance of the process. In this manner, the foulant is removed from the gas stream.

A bio-filter system is disclosed. The disclosed bio-filter system comprises: a transfer pipe for collecting and transferring N.sub.2O generated in any one tank from among an anaerobic tank, an anoxic tank, and an aeration tank; a bio-filter unit including a carrier for removing, by means of microbial reaction, the N.sub.2O discharged from the transfer pipe; and a sewage supply member for spraying sewage into the carrier in order to provide nourishment for microorganisms to the carrier. The bio-filter unit comprises: a filter housing; an induction discharge pipe, which is installed on the lower side of the inside of the filter housing, for inducing the N.sub.2O transferred by the transfer pipe in a transverse direction and enabling same to be discharged upwardly through a nozzle; the carrier, which is disposed on the upper side of the induction discharge pipe inside the filter housing, for removing, by means of microbial reaction, the N.sub.2O discharged through the induction discharge pipe; and a sewage spraying member, which is disposed on the top of the carrier inside the filter housing, for spraying sewage supplied from the sewage supply member to the carrier so as to utilize the sewage as nourishment for microorganisms.

A process for preparing a zeolitic material containing YO.sub.2 and X.sub.2O.sub.3, where Y and X represent a tetravalent element and a trivalent element, respectively, is described. The process includes (1) a step of preparing a mixture containing one or more structure directing agents, seed crystals, and a first zeolitic material containing YO.sub.2 and X.sub.2O.sub.3 and having FAU-, GIS-, MOR-, and/or LTA-type framework structures; and (2) a step of heating the mixture for obtaining a second zeolitic material containing YO.sub.2 and X.sub.2O.sub.3 and having a different framework structure than the first zeolitic material. The mixture prepared in (1) and heated in (2) contains 1000 wt % or less of H.sub.2O based on 100 wt % of YO.sub.2 in the framework structure of the first zeolitic material. A zeolitic material obtainable and/or obtained by the process and its use are also described.