Abstract: Chlorite-like phyllosilicate materials are found useful as SOx sorbents. A novel process of sulfur oxide sorption is provided utilizing these layered materials as contact solids. Typical industrial applications include sulfur removal from fluid catalyst cracking process, cold-side combustion gas sulfur abatement and cleaner coal gasification.

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: 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: In the control of pollutants such as NOx in the exhaust gases from internal combustion engines, ozone is reacted with NO to form NO2, which is then reduced catalytically to N2.

Abstract: A flue gas desulfurization apparatus includes at least one activated carbon fiber board 20 provided in a catalyst unit 6, the board being formed by alternatingly juxtaposing one or more plate-like activated carbon fiber sheets and one or more corrugated activated carbon fiber sheets so as to provide vertically extending conduits, wherein water for producing sulfuric acid is supplied, through a capillary phenomenon, to the activated carbon fiber board 20 provided in the catalyst unit 6. The flue gas desulfurization apparatus attains removal of sulfur oxides (SOx) by adding a minimum required amount of water to the activated carbon fiber board 20 so as to attain uniform water distribution and can reduce the amount of water required for removing sulfur oxides (SOx).

Abstract: A gas stream containing at least one fluorine compound selected from the group consisting of compounds of carbon and fluorine, compounds of carbon, hydrogen and fluorine, compounds of sulfur and fluorine, compounds of nitrogen and fluorine and compounds of carbon, hydrogen, oxygen and fluorine is contacted with a catalyst comprising at least one of alumina, titania, zirconia and silica, preferably a catalyst comprising alumina and at least one of nickel oxide, zinc oxide and titania in the presence of steam, thereby hydrolyzing the fluorine compound at a relatively low temperature, e.g. 200°-800° C., to convert the fluorine of the fluorine compound to hydrogen fluoride.

Abstract: To reduce the number of particles in an exhaust gas (A), in particular in the exhaust gas (A) from an internal-combustion engine, sulfur dioxide SO2 which is contained in the exhaust gas (A) is at least partially catalytically oxidized, in the presence of ammonia NH3 in a catalytic converter system having a catalytic activity which increases in the direction of flow, to form sulfur trioxide SO3. The simultaneous presence of sulfur trioxide SO3 and ammonia NH3 in the exhaust-gas stream which is brought about in this way results in an agglomeration of the small and very small particles and reduction in the number thereof.

Abstract: The present invention provides a process for the preparation of carbon monoxide gas (CO gas) that is free of sulfur compounds to the greatest possible extent and a process to use that gas in chemical syntheses, for example, for the synthesis of phosgene from carbon monoxide and chlorine.

Abstract: A petroleum coke-based combined De-SOx and De-NOx process is described comprising use of four key units, namely, a flue gas concentrator (FC), a carbothermal reducer (CR), an elemental sulphur condenser (SC) and an oxidizer for reduced sulphur and nitrogen species (RO). The two major reactants in this process are the petroleum coke, preferably, and a flue gas containing SOx/NOx. The major products are elemental sulphur from the SC and activated coke from the CR. The process provides for SOx and NOx abatement in an economically viable way while the activated coke produced has a wide range of applications, particularly, in environmental protection.

Abstract: The invention relates to: a process for the desulphurization of feed streams comprising: supplying a hot process stream to a lead catalyst bed (8) comprising a first sulphur-removing catalyst and a second sulphur-removing catalyst under conditions whereby sulphur is removed from the process stream by the first sulphur-removing catalyst and said second sulphur-removing catalyst does not effectively remove sulphur from the stream at the operating temperature of the lead catalyst bed for the duration of the bed's life; collecting a hot partially sulphur-depleted stream from the lead catalyst bed and cooling said stream; passing said cooled stream through a lag catalyst bed (11) comprising the first sulphur-removing catalyst and the second sulphur-removing catalyst under conditions whereby sulphur is removed from the process stream by the second sulphur-removing catalyst and said first sulphur-removing catalyst removes sulphur less efficiently from the stream at the operating temperature of the lag catalyst bed;

Abstract: A flue gas processing apparatus for removing sulfur oxide contained in a gas, including a desulfurization tower through which the gas flows, the desulfurization tower including a catalyst unit having at least one activated carbon fiber board which adsorbs the sulfur oxide and a water-supply device configured to supply water to the catalyst unit so as to form sulfuric acid from the sulfur oxide adsorbed to the at least one activated carbon fiber board, the water-supply device being positioned above the catalyst unit in the desulfurization tower, and a pressurizing device configured to apply pressure to the gas supplied to the desulfurization tower so as to flow the gas through the catalyst unit by the pressure.

Abstract: A gas stream containing at least one fluorine compound selected from the group consisting of compounds of carbon and fluorine, compounds of carbon, hydrogen and fluorine, compounds of sulfur and fluorine, compounds of nitrogen and fluorine and compounds of carbon, hydrogen, oxygen and fluorine is contacted with a catalyst comprising at least one of alumina, titania, zirconia and silica, preferably a catalyst comprising alumina and at least one of nickel oxide, zinc oxide and titania in the presence of steam, thereby hydrolyzing the fluorine compound at a relatively low temperature, e.g. 200°-800° C., to convert the fluorine of the fluorine compound to hydrogen fluoride.

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: An active carbon for use in the treatment of exhaust gas can be obtained by heat-treating a starting active carbon fiber derived from polyacrylonitrile, pitch or the like or a starting particulate active carbon in a non-oxidizing atmosphere. The heat-treating temperature is preferably in the range of 600 to 1,200 ° C. for use in the desulfurization of exhaust gas, and in range of 600 to 1,000° C. for use in the denitration of exhaust gas. By using the resulting heat-treated active carbon for the purpose of desulfurization, the sulfur oxide concentration in exhaust gas can be reduced to 5 ppm or below. Moreover, by using the heat-treated active carbon in combination with conventional denitration based on selective catalytic reduction, the nitrogen oxide concentration in exhaust gas can be reduced to 1 ppm or below.

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: Methods for removing sulfur from syngas in a Fischer-Tropsch reactor, and reactors including means for removing sulfur from syngas are disclosed. Sulfur-reactive metals can be used in the Fischer-Tropsch unit to sequester the sulfur. For example, the Fischer-Tropsch unit can be run in stages, using a sacrificial catalyst in a first stage to adsorb the sulfur. The Fischer-Tropsch reactor can include internal baffles that separate the reactor into zones, with a sacrificial catalyst in one or more of the zones, that can be easily sequestered and regenerated or replaced. Sulfur adsorbents can be placed in the inlet gas manifold. A portion of the Fischer-Tropsch catalyst can be converted into larger size pellets that do not fluidize with the firer grain Fischer-Tropsch catalyst and remain near the gas inlet where they adsorb and sequester the sulfur. These embodiments can be combined in any suitable manner to lower the sulfur concentration in the syngas feed.

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 of manufacturing a synthesis gas containing hydrogen and carbon monoxide comprises steps of removing only hydrogen sulfide from a natural gas containing hydrogen sulfide and carbon dioxide by permitting the natural gas to pass through a hydrogen sulfide-removing device filled with a hydrogen sulfide absorbent, adding carbon dioxide and steam to the natural gas which the hydrogen sulfide has been removed to prepare a mixed gas, and feeding the mixed gas into a reaction tube of a reformer, thereby permitting mainly a steam reforming reaction to take place in the mixed gas. This method enables hydrogen sulfide in natural gas to be removed while permitting the carbon dioxide of natural gas to be effectively utilized, thereby reducing the quantity of carbon dioxide to be added to the natural gas to be transferred to the reformer.

Abstract: A petroleum coke-based combined De-SOx and De-NOx process is described comprising use of four key units, namely, a flue gas concentrator (FC), a carbothermal reducer (CR), an elemental sulphur condenser (SC) and an oxidizer for reduced sulphur and nitrogen species (RO). The two major reactants in this process are the petroleum coke, preferably, and a flue gas containing SOx/NOx. The major products are elemental sulphur from the SC and activated coke from the CR. The process provides for SOx and NOx abatement in an economically viable way while the activated coke produced has a wide range of applications, particularly, in environmental protection.

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: 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: A catalytic composition and method of making the same in which a catalytic material has an average pore size distribution sufficiently large to substantially prevent capillary condensation.

Abstract: The present invention provides a desulfurization apparatus 10 for desulfurizing a flue gas 13 containing sulfur oxides through contact with a porous carbon material 11. The carbon material 11, which is provided in a desulfurization tower 12, is at least one species selected from activated carbon and activated carbon fiber. The apparatus 10 contains an NO2-gas-feeding apparatus 14 for feeding NO2 gas into the desulfurization tower 12. Within the desulfurization tower 12, showering means 15 is provided at the top, the showering means adjusting the water content of the flue gas in the desulfurization tower to that corresponding to saturation with water vapor or higher at the treatment temperature.

Abstract: Active carbon catalyst for recovering and removing sulfur oxides contained in flue gas by turning them into sulfuric acid by a catalytic desulfurization reaction. Powdery active carbon and fluororesin are kneaded by shearing force before being molded to a desired profile so that the inter-particulate gaps of powdery active carbon particles are made water-repellent. Flue gas preferably flows downwardly through a tower filled with such an active carbon catalyst, which is made to show a honeycomb structure having surfaces running only in a direction parallel to the flow. The activity of the catalyst maintains an enhanced level if dilute sulfuric acid or water is introduced into the active carbon from the top of the tower to cleanse the surface of the active carbon catalyst so that the catalyst layer is prevented from being clogged and contaminated by ashes and soot contained in flue gas.

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: 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: A process for the treatment of sludge which produces a dry sludge free of pathogenic and non-pathogenic microorganisms enriched with nitrogen which can be used as a fertilizer, and which uses as raw materials: elemental sulfur, formaldehyde, ammonia, urea, chlorine, and sulphuric acid, and comprises the steps of feeding the sludge into a pre-dryer into which is fed a hot gas stream containing sulfur trioxide produced by the combustion and catalytic oxidation of sulfur with air and finally completely drying the sludge by feeding it into an ammoniator.

Abstract: A sorbent composition comprising a reduced-valence promoter and a steam-treated support can be used to desulfurize a hydrocarbon-containing fluid such as cracked-gasoline or diesel fuel.

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: 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: In the control of pollutants such as NOx in the exhaust gases from internal combustion engines, ozone is reacted with NO to form NO2, which is then reduced catalytically to N2, by reacting NO2 with ammonia. The NO2 produced can react with the particulates of Diesel engine to exhaust gas to regenerate a particulate filter.

Abstract: A process for the recovery of sulphur trioxide, solutions of sulphuric acid, or organic derivatives thereof, using organic compounds and/or supercritical fluids, and catalyst. The process comprises the steps of passing a mixture of SO2 and an oxygen-containing gas over an activated carbon catalyst at a temperature of at least 15° C. and preferably at a pressure of 1-200 atmospheres, and stripping the activated carbon with either (i) a liquid organic compound selected from the group consisting of ketones, ethers, decalin, tetrahydrofurans, sulpholanes, glymes and formamides and which is non-reactive with sulphur trioxide or sulphuric acid, or (ii) a liquid organic compound capable of forming organic sulphates or sulphonates by reaction with sulphur trioxide or sulphuric acid. The process may be used to obtain sulphuric acid, or organic sulphates or sulphonates.

Abstract: A process for adjusting the ratio of sulfur dioxide to hydrogen disulfide from the regeneration of a catalytic system of a structured support for example a monolith coated with: (i) a metal oxide sorber component selected from the group consisting of Ti, Zr, Hf, Ce, Al, Si and mixtures thereof, for example Ti2O, (ii) a precious metal component, for example Pt metal and, optionally (iii) a modifier consisting of an oxide Ag, Cu, Bi, Sb, Sn, As, In, Pb, Au or mixtures thereof, such as Cu as copper oxide. The system first captures the gaseous sulfur compounds. Then the captured gaseous sulfur compounds are then desorbed as mainly H2S and SO, in higher concentrations in a separate isolated lower flow stream in a ratio determined by the amount of modifier in the catalyst. The higher concentrations may be processed to less noxious or useful sulfur materials and the catalyst/sorber is regenerated.

Abstract: A polluted fluid, such as exhaust gas from a refuse incinerator, containing at least one pollutant, such as volatile organic compounds (VOCs), SOx or NOx, is processed by passing the polluted fluid through an adsorbing layer containing a high-silica adsorbent capable of adsorbing both ozone and at least one pollutant to adsorb at least one pollutant on the adsorbent. Then, ozone is brought into contact with the adsorbing layer to oxidize and decompose the pollutant adsorbed on the adsorbent, while stopping the flow of the polluted fluid.

Abstract: The invention provides a multistep process for preparing a low-sulfur reformate gas for use in a fuel cell system by catalytic steam reforming of a reactant gas mixture comprising introducing a sulfur-containing hydrocarbons and steam in a first step to make a reformate, passing the reformate leaving the first step over a sulfur absorber either directly or only after passage through the second step, and reducing the carbon monoxide content of the reformate obtained in a second step, wherein the reactant gas mixture which comprises a steam/carbon ratio and desorbing the sulfur components optionally absorbed on the catalysts in both process steps by periodically raising the temperature and also passing the catalysts over the absorber, wherein the temperature of the absorber during operation of the process is always kept within a temperature interval which is an optimum for the absorber.

Abstract: Methods for removing sulfur from syngas in a Fischer-Tropsch reactor, and reactors including means for removing sulfur from syngas are disclosed. Sulfur-reactive metals can be used in the Fischer-Tropsch unit to sequester the sulfur. For example, the Fischer-Tropsch unit can be run in stages, using a sacrificial catalyst in a first stage to adsorb the sulfur. The Fischer-Tropsch reactor can include internal baffles that separate the reactor into zones, with a sacrificial catalyst in one or more of the zones, that can be easily sequestered and regenerated or replaced. Sulfur adsorbents can be placed in the inlet gas manifold. A portion of the Fischer-Tropsch catalyst can be converted into larger size pellets that do not fluidize with the finer grain Fischer-Tropsch catalyst and remain near the gas inlet where they adsorb and sequester the sulfur. These embodiments can be combined in any suitable manner to lower the sulfur concentration in the syngas feed.

Abstract: A method of treating exhaust from an internal combustion engine having an emission reduction device, such as a lean NOx trap. Exhaust from the engine is directed to a first sulfur trap, which treats the exhaust and discharges exhaust that is substantially free of sulfur. The exhaust from the first sulfur trap is normally directed to the emission reduction device, but is diverted to a second sulfur trap when the first sulfur trap is saturated. During this diversion, a reducing agent introduced upstream of the first sulfur trap aids in purging the first sulfur trap and in reducing metal sulfates and metal sulfites in the first sulfur trap to hydrogen sulfides, which are then treated by the second sulfur trap. When the first sulfur trap is thus purged, the exhaust gas is again directed to the emission reduction device.

Abstract: In general, the invention provides methods and associated apparatuses for removing odorant and sulfur compounds from a gas stream such as natural gas. As an example, such systems are typically required by fuel processor systems adapted to convert natural gas into reformate for use in fuel cell systems, where the odorant and sulfur compounds might otherwise poison the fuel processor and fuel cell catalysts Systems under the present invention are based on the use of at least two filtration stages such that the odorant removal function is segregated from the general removal of H2S.

Abstract: The present invention pertains to Mg—Al anionic clay having 3R2 stacking. This new polytype of anionic clay has a three-layer repeat, but it has a different interlayer arrangement than the conventional 3R1 hydrotalcite. Said new polytype can be applied in all applications described before for the conventional 3R1 polytype anionic clay such as in catalyst compositions, catalyst additive compositions, catalyst supports, absorbent compositions, stabilizer compositions and in medicaments.

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: 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 method of treating exhaust from an internal combustion engine having an emission reduction device, such as a lean NOx trap, such that sulfur dioxide does not pass through the emission reduction device. Exhaust from the engine is directed to a first sulfur trap, which treats the exhaust and discharges exhaust that is substantially free of sulfur. The exhaust from the first sulfur trap is normally directed to the emission reduction device, but is diverted to a second sulfur trap when the first sulfur trap is saturated. During this diversion, a reducing agent introduced upstream of the first sulfur trap aids in purging the first sulfur trap and in reducing exhaust in the first sulfur trap to hydrogen sulfides, which are then treated by the second sulfur trap. When the first sulfur trap is thus purged, the exhaust gas is again directed to the emission reduction device.

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: Porous, preferably dimensionally stable material and a method for using for the removal of gaseous impurities from a gas mixture, such as H2S, COS, CH2, and SO2, into the pores of which there is incorporated a secondary amine which chemically bonds with the constituents to be removed, with the material including a hydrophobic polymer with pores having an average diameter in the range of from 0.1 to 50 &mgr;m and a secondary amine having hydrophobic properties which optionally is incorporated into a hydrophobic liquid is disclosed. Favorable results have been attained using polypropylene as the hydrophobic polymer and ditridecyl amine as the secondary amine, with a tertiary amine, such as C12 to C14-alkyl diethanol amine, being part of the hydrophobic liquid.

Abstract: A heat generation process with reduced emissions of oxides of sulphur is described in which: