Abstract: Zeolite L with flat basal planes, and reduced crystallite size is prepared in a synthesis modified by the addition of small amounts of additional metal such as magnesium, calcium, barium, cobalt, zinc, chromium, manganese or nickel. The addition of these metals also suppresses unwanted zeolite W formation even when the synthesis would otherwise form this zeolite.

Abstract: An exhaust gas treatment process useful for the removal of nitrogen oxides using an iron impregnated zeolite as the catalyst and ammonia as a reducing agent. It is desired to extend the effective temperature range for the selective catalytic reduction (SCR) of nitrogen oxides below about 400.degree. C. This is accomplished in the instant invention through the use of an intermediate pore size zeolite, such as ZSM-5, based catalyst which has been ferrocene treated to substantially incorporate iron into its pores. The catalyst may also be hydrothermally treated at least once, if desired.

Abstract: Distribution of pollution reducing agents within an effluent at the effective temperature window for effective gas phase reaction is greatly improved. A two-phase mixture having fine droplets of liquid, e.g. a NO.sub.x reducing agent such as aqueous solutions of urea or ammonia, dispersed in a gaseous component, such as air, is injected into the effluent an sonic velocity to achieve a distribution of particles of sizes effective to uniformly reduce NO.sub.x within the zone of effective temperature while not producing a significant level of droplets so large that they survive beyond the temperature zone.

Abstract: A catalyst for the selective reduction of nitric oxide NO in flue gas to nitrogen using ammonia NH.sub.3 comprises oxidatively heat treated manganese oxide loaded on a porous substrate of gamma-alumina or titania- or titania-/WO.sub.3 -modified silica.

Abstract: A plate-shaped article is immersed in a cleaning liquid filling a cleaning bath having an overflowing surface through which the cleaning liquid flows out, and is rinsed out. In the cleaning bath, streams mostly being directed away from a predetermined plane approximately perpendicular to the overflowing surface are formed. The plate-shaped article is then brought into the cleaning liquid having the stream maintaining a state where the plate-shaped article intersects the predetermined plane and the surfaces of the plate-shaped article are in approximately parallel to the streams mostly being directed away from the predetermined plane on the surface of the cleaning liquid.

Abstract: The invention describes a highly efficient catalytic pollution control process for removing N.sub.2 O from gaseous mixtures. The process utilizes catalysts derived from anionic clay minerals, which after appropriate heat activation, provide superior N.sub.2 O decomposition activity. The catalytic process comprises contacting an N.sub.2 O-containing gaseous mixture with the decomposition catalyst under conditions sufficient to convert the N.sub.2 O into gaseous nitrogen and gaseous oxygen. The process catalysts are derived from anionic clay materials such as the hydrotalcites, sjogrenites and pyroaurites. A small but critical amount of an activator metal is provided to promote the decomposition of N.sub.2 O, particularly in wet gas steams. The activator metal may be an alkali metal such as sodium, potassium or lithium, or an alkaline-earth metal such as magnesium, with sodium giving particularly good results.

Abstract: A process for purifying a gas containing nitrogen monoxide to remove nitrogen monoxide therefrom, includes adjusting oxygen content of the gas to provide a quantity of oxygen which is at least equal to a stoichiometric quantity which is necessary in order to oxidize the nitrogen monoxide contained in the gas to nitrogen dioxide; contacting the gas, substantially in the absence of any liquid, with an alkali metal pyrosulphite which is a solid and which is employed in a quantity which is sufficient to convert the nitrogen monoxide contained in the gas to alkali metal nitrite and alkali metal nitrate; and removing the alkali metal nitrite and the alkali metal nitrate from the gas.

Abstract: A process for impregnating zeolite with a quaternary ammonium cation (QAC) and then coating the impregnated zeolite with permanganate (such as potassium permanganate), and for impregnating zeolite with permanganate and then coating the impregnated zeolite with a QAC, and coated, impregnated zeolite crystals resulting from either process. Either coating acts as a protective agent for the impregnating substance in each zeolite crystal's interior, and allows regulated time release control of the impregnating substance, thus permitting a controlled diffusion (or absorption) rate in applications in which the coated, impregnated zeolite is employed to absorb contaminants from air or water. Combinations of coated and uncoated zeolite crystals can be chosen to match specific environmental circumstances calculable by analysis of the air or water to be treated.

Abstract: A multi-bed process of removing sulfur oxides and/or other combustible sulfur-containing compounds from a gas stream including combusting the other combustible sulfur-compounds when present in the gas stream with air or oxygen to convert such sulfur-containing compounds to sulfur oxide and form a sulfur oxide enriched gas stream. The sulfur oxide enriched gas stream is contacted with first and second serially connected solid adsorbent beds for adsorbing the sulfur oxides in the form of inorganic sulfates and/or sulfur oxides. A third adsorbent bed is contacted with a reducing gas stream to regenerate the bed by reducing the retained inorganic sulfates and/or sulfur oxides to hydrogen sulfide and/or sulfur dioxide, to thereby form a hydrogen sulfide and/or sulfur dioxide bearing stream. The feeds to each of the beds are realigned to place the second and third beds in series with the sulfur oxide and/or sulfur dioxide enriched stream being fed to the second bed and to place the first bed in a regenerative mode.

Abstract: Methods of reducing NO.sub.x to nitrogen without using a reducing gas. The NO.sub.x is absorbed in a heteropoly compound to concentrate it and then heated to reverse the fixation reaction(s) and decompose the NO.sub.x into nitrogen.

Abstract: Sulfur oxides are removed from a gas containing same by contacting the gas with a system including ammonium, potassium, and/or sodium salts in a solid phase and ammonium, sodium, and/or potassium hydrogen sulfate in a liquid phase. The sulfur oxides react with the solid phase to form a hydrogen sulfate in a liquid phase. The hydrogen sulfate is regenerated and returned to the reaction zone as a sulfate. Sulfuric acid may be produced as a byproduct. Ammonia injection into the gas stream which optionally contains nitrogen oxides, converts the nitrogen oxides into nitrogen. The excess ammonia reacts with the sulfur oxides to precipitates in the sulfur oxides reaction zone.

Abstract: The present invention relates to a process for reducing the nitrogen oxides level in an effluent from the combustion of a carbonaceous fuel, which involves preparing an emulsion of a nitrogen oxides reducing treatment agent and a hydrocarbon having a boiling point which is lower than that of said nitrogen oxides reducing treatment agent; and introducing said emulsion into the effluent from the combustion of a carbonaceous fuel under conditions effective to reduce the nitrogen oxides level therein.

Abstract: In the device for selective non-catalytic reduction of nitrogen oxides, a liquid nitrogen-containing reducing agent is sprayed through two-component lances into a stream of hot flue gases. Spraying occurs in pulsatory operation at a frequency of 5 to 70 per second, preferably 10 to 20 per second. As a result of this mode of operation, a spray cone of relatively coarse long-range drops and a spray cone of relatively fine short-range drops are produced alternately at each two-component nozzle. The reducing agent is ammonia dissolved in water (ammonia solution) at flue-gas temperatures of 1060.degree. C. to 1170.degree. C. The device for working the method comprises a flue-gas duct 3 incorporating a number of two-component lances 4 operated by a pressure medium.

Abstract: An exhaust gas treatment process useful for the removal of nitrogen oxides using an iron containing zeolite as the catalyst and ammonia as a reducing agent. It is desired to extend the effective temperature range for the selective catalytic reduction (SCR) of nitrogen oxides below about 400.degree. C. This is accomplished in the instant invention through the use of an intermediate pore size zeolite, such as ZSM-5, based catalyst which has been treated to incorporate iron into its pores.

Abstract: A process for removing nitrogen oxides from oxygen rich exhaust gas containing nitrogen oxides and hydrocarbons using a catalyst composed of at least one active metal and zeolite having a molar ratio of SiO.sub.2 /Al.sub.2 O.sub.3 of at least 15, treated with a vapor of at least one silicon compound selected from alkylchlorosilanes, alkoxysilanes, alkoxyalkylsilanes, and silicon tetrachloride or treated with an alkoxysilane or silicon tetrachloride in an organic solvent.

Abstract: The amount of N.sub.2 O emission from a fluidized bed reactor is reduced by adding a hydrogen radical providing additive (e.g. a hydrogen containing fuel such as natural gas or alcohol) to the flue gases discharged from the fluidized bed. Sufficient oxygen is present in the flue gases--either by addition with the additive, or by addition of an excess to the combustion chamber--so that the additive reacts with the oxygen, typically raising the temperature of the flue gases (e.g. from about 700.degree.-900.degree. C. to about 950.degree.-1100.degree. C.) that is from about 1292.degree.-1652.degree. F. to about 1742.degree.-2012.degree. F. so that N.sub.2 O production is reduced about 10-90%. The additive may be injected in or just prior to a cyclone for separating particles from the flue gases, in a gas discharge immediately after the cyclone (e.g.

Abstract: Disclosed is a method of adsorbing and removing NOx, by washing with water a gas discharged by ventilation from highway tunnels in a washing tower as pretreatment, and then adsorbing NOx in the gas with a rotary NOx adsorption unit. The washed gas may be heated by a heater which is placed between the washing tower and the rotary NOx adsorption unit.

Abstract: An arsenic-resistant composite oxide catalyst containing oxides of at least the metals vanadium and molybdenum, in particular for reducing nitrogen oxides in flue gases in the presence of a reducing agent, such as ammonia or carbon monoxide, includes at least one composite oxide phase with a general formula V.sub.x Mo.sub.y O.sub.32, where x+y.ltoreq.12 and where x.gtoreq.1 and y.gtoreq.1, and optionally a MoO.sub.3 phase. A method for producing an arsenic-resistant composite oxide catalyst includes mixing vanadium oxide and molybdenum oxide or a precursor thereof with one another to form a mixture, heating the mixture to a temperature at which a mixture of oxides is present, preferably in completely molten form, then cooling down the mixture to form at least one composite oxide phase with a general formula V.sub.x Mo.sub.y O.sub.32, and then subjecting the composite oxide phase to a reducing treatment to prepare a lower-oxygen composite oxide phase with the same structure.

Abstract: Molecular sieves are modified by an ion exchange process where metal cations are introduced into the molecular sieves by means of solid state ion exchange. The solid state ion exchange can be carried out as follows: a weighed amount of calcined and activated zeolite is intimately mixed with a precalculated amount of PtCl.sub.2, PdCl.sub.2, RhCl.sub.3, CuCl.sub.2, V.sub.2 O.sub.5 or another compound of the noble metals (e.g., corresponding halides or oxides), the solids mixture is then heated in a current of inert gas (e.g., a current of helium gas or of nitrogen) to temperatures of 400.degree. to 600.degree. C., then cooled down to room temperature and subsequently reduced in a current of hydrogen for 10 to 14 hours at 280.degree. to 350.degree. C. in order to produce small metal clusters from the cationically introduced metal.

Abstract: A method for denitrating an exhaust gas is disclosed which comprises the steps of injecting ammonia from an ammonia injection device into a high-temperature exhaust gas containing nitrogen oxides in a temperature range of 480.degree. C. or more, and then bringing a mixture of ammonia and the high-temperature exhaust gas into contact with a denitration catalyst to reduce the mixture, said method being characterized in that ammonia is injected through the ammonia injection device in which at least an inner surface is subjected to an aluminizing treatment, whereby ammonia is prevented from decomposing; and an apparatus for denitrating an exhaust gas is also disclosed.