Abstract: An automobile exhaust system includes a catalytic converter, a NOx trap, and a sulfur oxide trap. The sulfur oxide trap improves the efficiency of the NOx trap. Sulfur oxide has a deleterious effect on the performance of nitrogen oxide traps. The sulfur oxide trap comprises a monolithic substrate which is over-coated with an aluminum oxide layer and a mixed oxide layer of calcium oxide and magnesium oxide. In a variation, a sulfur oxide trap is integrated with a nitrogen oxide trap by coating the catalyst contained within a nitrogen oxide trap with a mixed oxide layer of calcium oxide and magnesium oxide. In each embodiment, the sulfur oxide trap can be regenerated by heating at elevated temperature for a short time period.

Abstract: A multiple-field precipitator, flue-gas treating device, in accordance with the principles of the invention, includes a first section having a dual-function, sensible-cooling heat exchanger/electrostatic precipitator, a second section having a wet electrostatic precipitator, and a middle section fluidly connecting the first and second sections. In the first section, the exchanger/precipitator sensibly cools the flue gas and collects most of the dust from the flue gas. In the middle section, the dust-reduced flue gas is combined with an alkaline material, thereby forming reaction products. These reaction products and several other pollutants are captured by the wet electrostatic precipitator, in the form of a pollutant-laden liquid. The pollutant-laden liquid is directed to a series of heat exchangers and settling tanks, where various pollutants such as SOx, metals, NOx, and chlorides are removed in different stages.

Abstract: Process and device for regeneration of a used absorbent from a desulfurization zone or from the desulfurization of a gas containing sulfur oxides, comprising regeneration simultaneously with filtering of the absorbent, in a reducing atmosphere, wherein partial combustion of a regeneration gas is also carried out upstream from regeneration, the products of the partial combustion being mixed with the used absorbent prior to the regeneration-filtration stage. The absorbent may be, e.g., solid absorbents based on magnesium oxide. The regeneration gas may be hydrogen sulfide and/or a hydrocarbon. For example, H2S can be partially combusted and the products of the partial combustion, including H2S, H2, SO2 and sulfur, mixed with the used absorbent prior to the regeneration-filtration stage.

Abstract: For reducing emissions of oxides of sulphur: a) a sulphur-containing fuel is burned in a combustion zone comprising a heat exchange zone in which at least a portion of the heat is extracted, and effluents or combustion fumes are recovered at a temperature in the range 800° C. to 1200° C.

Abstract: Active alumina catalysts, well suited for the Claus reaction, for the hydrolysis of organosulfur compounds and for catalytically removing objectionable sulfur compounds from gaseous effluents comprised thereof, contain a cocatalytically effective amount of sodium values, such effective amount, expressed by weight of Na2O, ranging from 1,200 ppm to 2,700 ppm.

Abstract: The liquid cooling spray in a gas conditioning chamber is modified by the addition of an alkali to scrub sulfuir dioxide and other acid forming gases and a separation unit to remove particles that may contain either unreacted alkali or salts of the acid forming gases. A slurry of fine particles of hydrated lime is injected into the liquid coolant under conditions that result in kernels of controllable size that contain the alkali or salts from reactions with the acid forming gases. The modified cooling liquid provides for a high sulfur dioxide collection efficiency at a low molar ratio of alkali to sulfur, while the specified kernel size range allows fbr efficient removal of the kernels from the gas.

Abstract: A sorbent material is provided comprising a material reactive with sulfur, a binder unreactive with sulfur and an inert material, wherein the sorbent absorbs the sulfur at temperatures between 30 and 200° C. Sulfur absorption capacity as high as 22 weight percent has been observed with these materials.

Abstract: The method of simultaneously reducing carbon dioxide (CO2) emissions and sulfur dioxide (SO2) emissions produced by the combustion of carbon-containing matter in a hearth consists in injecting into the hearth a calcium-based agent, a fraction of which absorbs SO2 after decarbonization, and then, after the flue gases have been subjected to intermediate cooling, in causing them to transit via a first reactor and in putting them in contact therein with the other fraction of the absorbant that has not reacted with SO2 so as to capture CO2 from the flue gases by carbonization, then, in a separator, in extracting the solids contained in the flue gases output from the first reactor so as to subject them to heat treatment in a second reactor in order to extract CO2 therefrom by decarbonization and in order to recycle the resulting regenerated CO2 absorbant to the first reactor.

Abstract: A method for the combined reduction of sulfur dioxide, SO2, and nitrogen oxides, NOx, in the gas stream of a furnace from the combustion of fossil fuels is disclosed. In a narrow gas temperature zone in a furnace, NOx is converted to nitrogen by reaction with a reducing agent such as urea or ammonia with negligible residual ammonia and other reaction pollutants. In about this same temperature zone, SO2 will react with calcium oxide particles, derived from the calcination of lime, Ca(OH)2, or limestone, CaCO3, to form CaSO4 particles. A wide size distribution of aqueous droplets, containing dispersed lime or very fine limestone particles and dissolved urea or ammonia, is injected at the outer edge of the furnace gas zone at which the SO2 and NOx reduction reaction are effective.

Abstract: The present invention relates to sulfur tolerant catalyst composites useful for reducing contaminants in exhaust gas streams, especially gaseous streams containing sulfur oxide contaminants. More specifically, the present invention is concerned with improved NOx trap catalysts for use in diesel engines as well as lean burn gasoline engines. The sulfur tolerant NOx trap catalyst composites comprise a platinum component, a support, and a NOx sorbent component prepared by hydrothermal synthesis. The NOx sorbent component comprises a first metal oxide and a second metal oxide. The metal in the first metal oxide is selected from the group consisting of aluminum, titanium, zirconium, silicon, and composites thereof, and the metal in the second metal oxide is selected from the group consisting of Group IIA metals, Group II metals, Group IV metals, rare earth metals, and transition metals. The metal in the first metal oxide is different from the metal in the second metal oxide.

Abstract: The present invention is a method of solidifying sulfur component being the cause of “SOx poisoning” by use of a sulfur solidifier. The solidifier includes a metal element having a function of oxidizing the sulfur component and a basic metal element. And the solidifier solidifies sulfur component before exhaust gas flows into an NOx-occluding reduction-type exhaust purifying catalyst located on an exhaust path. Since the foregoing sulfur solidifier includes the above metal element and the basic metal element, it can effectively solidify the sulfur component which are the cause of the SOx poisoning, and ensure improvement in purification performance.

Abstract: A process for cleaning flue gases containing ash and sulfur dioxide produced by burning sulfur-containing coal in the combustion chamber of a circulating fluidized-bed firing system includes delivering a particulate SO2 sorbent into the combustion chamber. A mixture including portions of the ash, the reaction product produced in the reaction of the SO2 sorbent with the sulfur dioxide, and unreacted SO2 sorbent is fed from the combustion chamber to a mixing unit. In the mixing unit, water or an aqueous sodium-containing solution is mixed with this mixture and the unreacted SO2 sorbent is converted into a hydration product (for example Ca(OH)2) at a reaction temperature of 60° to 100° and at atmospheric pressure. The ash, the reaction product, and the hydration product is returned from the mixing unit into the combustion chamber, and the hydration product is reactivated to an SO2 sorbent at a combustion-chamber temperature of 700° to 950° C.

Abstract: System for removal of targeted pollutants, such as oxides of sulfur, oxides of nitrogen, mercury compounds and ash, from combustion and other industrial process gases and processes utilizing the system. Oxides of manganese are utilized as the primary sorbent in the system for removal or capture of pollutants. The oxides of manganese are introduced from feeders into reaction zones of the system where they are contacted with a gas from which pollutants are to be removed. With respect to pollutant removal, the sorbent may interact with a pollutant as a catalyst, reactant, adsorbent or absorbent. Removal may occur in single-stage, dual-stage, or multi-stage systems with a variety of different configurations and reaction zones, e.g., bag house, cyclones, fluidized beds, and the like. Process parameters, particularly system differential pressure, are controlled by electronic controls to maintain minimal system differential pressure, and to monitor and adjust pollutant removal efficiencies.

Abstract: A process and system is disclosed for removing sulfur from tail-gas emitted from a Claus sulfur recovery process. First, the tail-gas is oxidized so as to convert sulfur therein to sulfur oxides. Oxidized tail-gas is directed into an absorber where a solid absorbent absorbs substantially all the sulfur oxides thereon. After allowing sufficient time for a desired amount of sulfur oxides to be absorbed, absorption is ceased. Next, the solid absorbent containing the absorbed sulfur oxides is contacted with a reducing gas so as to release an off gas containing hydrogen sulfide and sulfur dioxide. Upon releasing sulfur from the solid absorbent, the solid absorbent is regenerated and redirected into the absorber. Sulfur in the off gas emitted by regeneration is concentrated to an extent sufficient for use within a Claus sulfur recovery process for conversion to elemental sulfur.

Abstract: An integrated lean NOx trap. The integrated lean NOx trap includes a lean NOx trap containing a composite metal oxide mixture consisting essentially of about 80-100 wt % stoichiometric spinel MgAl2O4 and between about 0-20 wt % of CeO2 or CeO2—ZrO2. A method for removing NOx and SOx impurities from exhaust gases using the integrated lean NOx trap is also described.

Abstract: An exhaust gas purifying apparatus is provided which includes a three way catalyst provided in an exhaust pipe of an internal combustion engine; and a NOx adsorption/reduction catalyst provided in the exhaust pipe to be located downstream of the three way catalyst. Nickel serving as a catalyst source is loaded on an alumina support layer of the NOx adsorption/reduction catalyst. When the engine operates with a fuel-rich air/fuel mixture at a relatively small air-fuel ratio, a reducing atmosphere is formed around the NOx catalyst, and the reaction to convert NiO into NiS occurs, thereby to consume H2S. As a result, consumption of SO2 proceeds, and the reaction to convert BaSO4 as an oxidized product of sulfur deposited on the NOx catalyst into BaCO3 as an NOx adsorbent is accelerated in an oxidizing atmosphere, thereby resuming the purifying capability of the NOx catalyst.

Abstract: The present invention relates to sulfur tolerant catalyst composites useful for reducing contaminants in exhaust gas streams, especially gaseous streams containing sulfur oxide contaminants. More specifically, the present invention is concerned with improved NOx trap catalysts for use in diesel engines as well as lean burn gasoline engines. The sulfur tolerant NOx trap catalyst composites comprise a platinum component, a support, and a NOx sorbent component prepared by hydrothermal synthesis. The NOx sorbent component comprises a first metal oxide and a second metal oxide. The metal in the first metal oxide is selected from the group consisting of aluminum, titanium, zirconium, silicon, and composites thereof, and the metal in the second metal oxide is selected from the group consisting of Group IIA metals, Group III metals, Group IV metals, rare earth metals, and transition metals. The metal in the first metal oxide is different from the metal in the second metal oxide.

Abstract: Method for cleaning the atmosphere by adsorbing pollutants, e.g., hydrocarbons, ozone, carbon monoxide, nitrogen oxides, sulfur oxides, etc., contained in the atmosphere. The pollutant-containing atmosphere is contacted with an outer surface of a substrate, e.g., radiators, condensers, charge air coolers, transmission coolers, etc., which has been coated with an adsorptive material such as zeolites, molecular sieves, carbon, etc. The coated substrate is protected with an overcoat of at least one porous protective material such as alumina, silica and the like, such that the pollutants will come into contact with the adsorptive material, but harmful contaminants will be prevented from contacting the adsorptive material.

Abstract: A process for treating an exhaust gas from a lean-burn internal combustion engine containing sulfur, oxides (SOx) and at least one other atmospheric pollutant selected from HC, CO, NO and soot, which gas being untreated or having undergone some chemical and/or catalytic treatment, comprises the steps of absorbing a sulfate-forming SOx component in a solid absorbent material, passing gas containing SO2 to atmosphere and periodically replacing the absorbent material. A system for carrying out the process comprises exhaust passage and a sulfate absorber (26) comprising a substrate supporting a solid material for absorbing a sulfate-forming component from SOx in the exhaust gas, which sulfate absorber is adapted to be replaceable.

Abstract: A method and an apparatus for cleaning flue gases with particulate slaked lime are described. In the method, burnt lime is dry-slaked with water to a moisture content of at least 5% by weight, and the slaked lime is contacted with the flue gases within 1 minute of the slaking. Preferably, the slaked lime is mixed with recirculated powdered lime from the flue gas cleaning before contacting it with the flue gases.

Abstract: System for removal of targeted pollutants, such as oxides of sulfur, oxides of nitrogen, mercury compounds and ash, from combustion and other industrial process gases and processes utilizing the system. Oxides of manganese are utilized as the primary sorbent in the system for removal or capture of pollutants. The oxides of manganese are introduced from feeders into reaction zones of the system where they are contacted with a gas from which pollutants are to be removed. With respect to pollutant removal, the sorbent may interact with a pollutant as a catalyst, reactant, adsorbent or absorbent. Removal may occur in single-stage, dual-stage, or multi-stage systems with a variety of different configurations and reaction zones, e.g., bag house, cyclones, fluidized beds, and the like. Process parameters, particularly system differential pressure, are controlled by electronic controls to maintain minimal system differential pressure, and to monitor and adjust pollutant removal efficiencies.

Abstract: A pollution control apparatus and method to scrub sulfur dioxide uses a lime slurry consisting of small diameter hydrated lime particles injected into the cooling water of a gas cooling tower. The diameter of the lime slurry particles is selected to be less than about 25 microns so that the lime particles substantially dissolve during the evaporative lifetime of the spray droplets. A preferred embodiment of the pollution control apparatus uses an in-line wet grinder and classifier to produce slurry as required.

Abstract: A semi-dry process for removing SO2, from a waste gas involves the introduction of a water-bearing particulate solid alkaline absorbent, as a free-flowing powder, into an absorption zone. The waste gas is passed through the absorption zone to entrain the powder, forming a moving bed, while the SO2 is first dissolved in the aqueous phase to form an acid and the acid then reacts with the alkaline absorbent. The moving bed is continuously transported toward a gas/solids separator wherein solids, including a water-insoluble reaction product of the SO2, are removed from the gas stream and recovered. The recovered particulate solids are reconditioned for return to the absorption zone by admixing with a particulate alkaline material, e.g., Ca(OH)2, and water to form a coating of an aqueous slurry of the alkaline material on the recycled solids as the water-bearing particulate solid alkaline absorbent. The reconditioned, recycled solids are returned to the absorption zone containing 5-40 wt. % water.

Abstract: A process for the reduction of gaseous sulfur compounds in gaseous streams. The gaseous stream is contacted with a sorber, e.g., zinc oxide, which is cable of sorbing the sulfur compounds under sulfur sorbing conditions. The sorber is present in the form of one or more layers on the surface of a monolith carrier, e.g., cordierite. The layers of the sorber have a total thickness of at least 3 g/in3 of the carrier. The process is especially useful for the removal of gaseous sulfur compounds such as H2S from gaseous streams.

Abstract: A method is provided for cleaning a combustion exhaust gas containing impurities, such as sulfur oxides and hydrochloric acid, with an additive, such as calcium hydroxide, in a reactor. The combustion gas is passed into a wetting zone where water is injected into the gas. The wet combustion gas is then passed through additive injection zone where the additive is co-currently injected into the combustion gas at a location near the bottom of the injection zone. The additive injection zone is connected to the top of the wetting zone and expands conically outward from the gas discharge outlet of the wetting zone so that as the combustion gas (and additive) travel upward through the additive injection zone the velocity of the combustion gas (and additive) is decreased. The combustion gas and additive are then passed through a cylindrical section having a uniform diameter of a given height and connected to the top of the additive injection zone.

Abstract: A system for the manufacture of cement clinker from cement raw meal in which the off-gases of the cement clinker production line not only undergo denitrification but also undergo desulfurization, so that even sulfur-rich raw materials and fuels can be employed without exceeding the prevailing pollutant emission limits. A substream of the oversize material (30) discharged from the mixing chamber (29) of the precalcination stage (16) as solid sorbent may be combined with the off-gas (22) and/or with a partial gas discharge (38) of the rotary kiln off-gas in order to convert the sulfur oxides contained in those off-gases to calcium sulfate (34), which is subsequently separated from the system off-gas.

Abstract: Solid pulverulent reactive composition for the purification of a gas, the said composition comprising sodium bicarbonate and a caking inhibitor for sodium bicarbonate comprising lignite coke and/or a magnesium compound comprising magnesium (hydr)oxide. Process for the purification of a gas, according to which a reactive composition comprising sodium bicarbonate which is substantially devoid of silica is introduced into the gas and the gas is subjected to removal of dust.

Abstract: A method for substantially reducing sulfur-oxide emissions from an asphalt air-blowing process involves adding an emission-reducing additive to the asphalt prior to air-blowing, or early in the air-blowing process, and filtering the flue gases produced in the process. The emission-reducing additive includes at least one metal hydroxide, metal oxide, metal carbonate, or metal bicarbonate, where the metal is sodium, potassium, calcium, magnesium, zinc, copper, or aluminum. The filter is preferably of the fiber-bed type, and removes at least a portion of the sulfur-containing compounds via condensation. The filtered stream of flue gases is subjected to an incineration process before being passed into the atmosphere.

Abstract: A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

Abstract: A sulfur oxide storage material contains a magnesium-aluminum spinel (MgO.Al2O3) and can be used as a so-called “sulfur trap” to remove sulfur oxides from oxygen-containing exhaust gases of industrial processes. In particular, it can be used for the catalytic purification of exhaust gas from internal-combustion engines to remove the sulfur oxides from the exhaust gas in order to protect the exhaust gas catalysts from sulfur poisoning. The material displays a molar ratio of magnesium oxide to aluminum oxide in the range of over 1.1:1, and the magnesium oxide present in stoichiometric excess is homogeneously distributed in a highly disperse form in the storage material.

Abstract: The present invention is a process for separating acid gas from gaseous mixtures containing acid gas and at least one non-acid gas. The process comprises bringing the gas stream into contact with a multilayer composite membrane comprising a non-selective polymeric support layer and a separating layer comprising a blend of a water soluble polymer and one-half equivalent or more of an acid gas reactive salt based upon the repeating unit of the water soluble polymer, the acid gas reactive salt which is formed from a monovalent cation and an anion for which the pKa of the conjugate acid is greater than 3, wherein the multilayer composite membrane separates the acid gas from the gaseous mixture by selectively permeating the acid gas.

Abstract: A method for removing sulfur dioxide out of a gas is provided. The sulfur dioxide contaminated gas is contacted with an aqueous solution or slurry that contains a reagent, such as sodium carbonate or sodium bicarbonate, in a reactor that may be a spray drier or a quench reactor and a gas having a diminished quantity of sulfur dioxide; unreacted reagent; sulfate reaction product, and which is at a temperature in the range of about 130 to 200 ° F. and a humidity in the range of 10 to 70 percent is produced. Particulate calcium hydroxide is blown into this gas through a device, such as dry venturi. The dry venturi removes aerosols out of the gas and helps ensure that the downstream filter cake is porous and non-tacky. The gas is then passed through a filtering device so that solids in the gas accumulate on the filter device, thus forming a filter cake. At least a portion of the sulfur dioxide in the gas is removed via passage of the gas through this filter cake.

Abstract: A method of binding pollutants, such as sulfur dioxide, hydrochloric acid and/or hydrofluoric acid, in flue gas in one or more combustion plants.

Abstract: A process is provided for the removal of mercury and sulfur dioxide out a flue gas from, for example, power stations, smelters, waste incineration plants and crematories, by washing the flue gas with an oxidized, chloride-containing washing water, which may be sea water, which has been oxidized by either adding an oxidizing agent, such as sodium hypochlorite, or by passing an electric current through the washing water (which converts the chloride values into chlorine) so that the gaseous mercury is sorbed into the washing water and is converted into mercury (II) chloride complexes and the gaseous sulfur dioxide is sorbed into the washing water and converted into sulfuric acid, and subsequently passing the resulting mercury (II) chloride and sulfuric acid-containing washing water and the flue gas through a bed of calcium carbonate where the sulfuric acid and the calcium carbonate react to form calcium sulfate which is washed off the bed into the washing water.

Abstract: The useful life of SOx additives having a SO2→SO3 oxidation catalyst component and a SO3 absorption component can be extended by employing each of these components as separate and distinct physical particles, pellets, etc.

Abstract: Flue gas deriving from incinerators that burn refuse, wood, or sludge is cooled in a spray drier, freed of dust in a dust remover, optionally freed of hydrohalides and sulfur oxides in one or two washers, one downstream of the other, and filtered through a filter-bed adsorber packed with an adsorbent containing a calcium hydroxide and optionally activated charcoal or coke. The adsorber is cleaned at intervals. An aqueous suspension is prepared from some or all of the adsorbate collected from the filter when it is cleaned. The gas is brought into contact with the suspension in at least one part of the system upstream of the filter.

Abstract: A dust collecting apparatus and method for dedusting a Ca-containing gas using a ceramics filter is provided, in which a filter differential pressure elevation rate is suppressed. A desulferizing agent 103 and a mineral 106 containing MgO are supplied via a hopper 13, 15 a valve 14 and a feeder 16 into a pressurized fluidized-bed combustion furnace 1 together with coal 101 and air 102. A combustion gas 201 is dedusted by a cyclone 2 to become a combustion gas 301, the combustion gas 301 enters a filter container 3a, 3b having a ceramics filter 31a, 31b and is further dedusted. A combustion gas 401 which is dedusted is supplied into a gas turbine 4 to generate power, and combustion gas 501 heats a waste heat recovery boiler 5 which in turn drives a steam turbine 7. The mineral 106 containing MgO is added in the combustion gas 301 which flows in the ceramics filter 31a, 31b. Thereby MgO is added to the combustion gas so that the filter differential pressure elevation rate can be suppressed.

Abstract: The present invention relates to a &ggr;-Al2O3 sorbent impregnated with alkali salt and CuO, which has a superior SO2 sorption capacity and a high regeneration conversion rate. A &ggr;-Al2O3 sorbent of the present invention is impregnated with alkali salt and copper oxide, whose alkali salt and copper oxide(CuO) contents are 1 to 10 wt. % and 5 to 20 wt. % against 100 wt. % &ggr;-Al2O3 carrier, respectively. The &ggr;-Al2O3 sorbent of the invention has a superior SO2 sorption capacity and a high regeneration conversion rate, which facilitates efficient removal of SO2 by the conventional dry method.

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: A method for removing contaminants, such as sulfur dioxide, mercury and hydrochloric acid, out of flue gases is provided, said method including the steps of: treating the flue gases with a reagent, such as sodium carbonate, sodium bicarbonate and ammonium salts or mixtures thereof; selectively dissolving the sodium phosphates produced thereby in water; separating out the solids remaining in suspension in the solution; and crystallizing the purified sodium sulphate present in the above-mentioned solution. The sodium sulfate can be upgraded in glass working furnaces. The reagent can be obtained by heating an intermediate solution containing sodium bicarbonate; sodium carbonate; ammonium bicarbonate and ammonium carbonate, which was obtained from the Solvay process for manufacturing sodium carbonate.