Abstract: A method for removing ammonia from a gas stream divides the gas steam into a plurality of separate gas streams and sprays a dilute acid solution into the streams. The acid solution is aqueous sulfuric acid and ammonium sulfate is produced. A device is used to divide the gas stream, the device having a plurality of conduits in fluid communication with a plenum. Spray nozzles are located in each conduit to spray the acid solution into the gas streams. The device creates less than 10 Pa back pressure to the gas stream.

Abstract: The air pollution control system including: a flue gas duct through which flue gas flows; a heat exchanger provided to the flue gas duct; a limestone supply device for reducing SO3 in the flue gas supplies CaCO3 to the flue gas flowing in an upstream of the heat exchanger; an upstream SO3 measurement device measures the SO3 in the flue gas flowing in a stream upper than a position where the limestone supply device supplies the CaCO3; and a control device determines a quantity supplied of the CaCO3 based on a relationship between a quantity of the SO3 measured by the upstream SO3 measurement device and a molar ratio of SO3 to CaCO3 and which supplies the determined quantity supplied of the CaCO3 from the limestone supply device to the flue gas duct.

Abstract: The present invention provide a method for purifying exhaust gas in which nitrogen oxides (NOx) gas is removed from a combustion exhaust gas. The method for purifying exhaust gas according to the invention is characterized in that water vapor is further added to raw exhaust gas to be processed to increase the water vapor concentration in the exhaust gas and the resulting moisture-adjusted exhaust gas is introduced into a denitration catalyst layer. The water vapor concentration in the moisture-adjusted exhaust gas is preferably 22.0% by volume or less in the total of the water vapor originally contained in the raw exhaust gas and the added water vapor.

Abstract: Dry processes, apparatus, compositions and systems are provided for reducing emissions of sulfur oxides, and sulfur dioxide in particular, and/or HCl and/or Hg in a process employing a combination of a lime-based sorbent, in particular hydrated lime and/or dolomitic hydrated lime, and a sorbent doping agent administered to achieve coverage of a three-dimensional cross section of a passage carrying SOx and/or HCl and/or Hg-containing gases with a short but effective residence time at a temperature effective to provide significant sulfur dioxide and/or HCl and/or Hg reductions with high rates of reaction and sorbent utilization. The once-through, dry process can advantageously introduce the sorbent and sorbent doping agent dry or preferably as a slurry to enable uniform treatment. Preferred sorbent doping agents include water-soluble or water-dispersible copper and/or iron compositions which can be heated to an active form in situ by the flue gases being treated.

Abstract: Provided is a system for treating a flowing exhaust gas comprising a lean NOx trap, a catalyzed soot filter, an ammonia or an ammonia precursor metering system for metering ammonia or an ammonia precursor into the flowing exhaust gas; and an SCR catalyst, wherein the SCR catalyst is disposed downstream of the lean NOx trap and comprises copper and/or iron supported on a small pore molecular sieve.

Abstract: A method for removing SOx from a gas by using a modified polyethylene glycol solution to absorb the SOx in the gas. The modified polyethylene glycol solution is contacted with the gas containing SOx to absorb the SOx in the gas, wherein x=2 and/or 3, the modified polyethylene glycol is a product derived from etherifying hydroxyl groups in the molecules of ethylene glycol and/or polyethylene glycol and has a general formula: R1—(O—C2H4)n—O—R2, where n is a positive integer, R1 and R2 are the same or different and are each independently alkyl, alkenyl, alkynyl, acyl or aryl.

Abstract: Methods for removing sulfur dioxide from a gas stream are disclosed. A method may include passing a gas stream comprising SO2 through a gas scrubbing apparatus. A scrubbing liquor comprising hydroxide ions and at least one oxidation catalyst may be flowed into the gas scrubbing apparatus, thereby contacting the gas stream with the scrubbing liquor. In response to the contacting, at least 90 wt. % of the sulfur dioxide may be removed from the gas stream. Concomitant to the contacting, at least some of the sulfur dioxide may react with at least some of the hydroxide ions, thereby forming sulfite ions in the scrubbing liquor. Some of the sulfite ions may be oxidized, via the oxidation catalyst, thereby forming sulfate ions in the scrubbing liquor. A used scrubbing liquor may be discharged from the scrubbing apparatus.

Abstract: A catalyst article having an extruded support having a plurality of channels through which exhaust gas flows during operation of an engine, and a single layer coating or a bi-layer coating on the support, where the extruded support contains a third SCR catalyst, the single layer coating and the bilayer-coating contain platinum on a support with low ammonia storage and a first SCR catalyst. The catalytic articles are useful for selective catalytic reduction (SCR) of NOx in exhaust gases and in reducing the amount of ammonia slip. Methods for producing such articles are described. Methods of using the catalytic articles in an SCR process, where the amount of ammonia slip is reduced, are also described.

Abstract: The present relates to a method for producing calcium sulfate solid crystals and hydrochloric acid (HCl) from a calcium chloride solution comprising the steps of feeding a continuous stirred-tank reactor with a calcium chloride solution, sulfuric acid and water; mixing the calcium chloride solution, sulfuric acid and water in the reactor; and maintaining the reactor a temperature of less than about 70° C., converting the calcium chloride solution, sulfuric acid and water into HCl and calcium sulfate solid crystals. The method described herein can be incorporated as a means for regenerating HCl from CaCl2 solutions which are generated in the metallurgical industry when processing calcium-bearing ores for recovering metals like rare earth elements.

Abstract: In a broad form the present invention relates to a method for oxidation of a species comprising sulfur in an oxidation state below +4, such as H2S, CS2, COS and S8 vapor, to SO2 said method comprising the step of contacting the gas and an oxidant with a catalytically active material consisting of one or more elements taken from the group consisting of V, W, Ce, Mo, Fe, Ca, Mg, Si, Ti and Al in elemental, oxide, carbide or sulfide form, optionally with the presence of other elements in a concentration below 1 wt %, at a temperature between 180° C. and 290° C., 330° C., 360° C. or 450° C., with the associated benefit of such a temperature being highly energy effective, and the benefit of said elements having a low tendency to form sulfates under the conditions, with the related benefit of an increased stability of the catalytically active material. The other elements present may be catalytically active noble metals or impurities in the listed materials.

Abstract: A method for the reduction and prevention of mercury emissions into the environment from combusted fossil fuels or other off-gases with the use of hypobromite is disclosed. The hypobromite is used for the capture of mercury from the resulting flue gases using a flue gas desulfurization system or scrubber. The method uses hypobromite in conjunction with a scrubber to capture mercury and lower its emission and/or re-emission with stack gases. The method allows the use of coal as a cleaner and environmentally friendlier fuel source as well as capturing mercury from other processing systems.

Abstract: A flue gas stream arising from fossil fuel fired sources containing nitrogen oxide contaminants is conveyed through an exhaust duct into a quencher. In the quencher aqueous medium is sprayed into contact with the flue gas stream. The quenched flue gas stream is mixed with ozone distributed at a high velocity in a sub-stoichiometric amount for partial oxidation of NOxto form NO2 and prevent the formation of N2O5. The flue gas containing NO2 is absorbed into an acidic medium of a wet scrubber to form nitrous acid. In the scrubber the nitrous acid is mixed with selected compounds of ammonia to decompose the nitrous acid for release of nitrogen. With this process the consumption of ozone and the operating costs associated therewith eliminate the requirement to dispose of nitrate recovered from the scrubber purge stream.

Abstract: Catalytic cores for a wall-flow filter include juxtaposed channels extending longitudinally between an inlet side and an outlet side of the core, wherein the inlet channels are plugged at the outlet side and outlet channels are plugged at the inlet side. Longitudinal walls forming the inlet and outlet channels separate the inlet channels from the outlet channels. The walls include pores that create passages extending across a width of the walls from the inlet channels to the outlet channels. Catalysts are distributed across the width and length of the walls within internal surfaces of the pores in a manner such that the loading of each catalyst across the width varies by less than 50% from an average loading across the width.

Abstract: This disclosure features an exhaust aftertreatment system that includes a selective catalytic reduction catalyst that includes (1) a metal oxide catalyst and a metal zeolite catalyst, (2) a metal oxide catalyst that is other than a vanadium oxide catalyst and a vanadium oxide catalyst, or (3) a metal oxide catalyst that is other than a vanadium oxide catalyst together with a metal zeolite catalyst and a vanadium oxide catalyst. When used in a selective catalytic reduction system in a diesel engine, the catalyst composition can increase a conversion efficiency of nitrogen oxides (NOx) to nitrogen and water by a minimum of 2 percent compared to the metal zeolite catalyst alone, the metal oxide catalyst alone, or the vanadium oxide catalyst alone, when present.

Abstract: In a method for operating an exhaust gas after-treatment system for an internal combustion engine, the exhaust gas after-treatment system comprises at least one apparatus for generating a plasma and at least one SCR catalyst. The exhaust gas after-treatment system further comprises a device for metering a reactant for the SCR catalyst. According to the invention, the nitrogen oxides resulting from the operation of the apparatus for generating a plasma are taken into account in the method when metering the reactant for the SCR catalyst.

Abstract: Methods related generally to the removal of atmospheric pollutants from the gas phase, are provided. The methods involve contacting a first stream comprising NO and/or NO2 with a second stream comprising (ClO2)0 to provide a third stream comprising NO and NO2 at a molar ratio of about 1:1; and contacting the third stream with a fourth stream comprising an aqueous metal hydroxide (MOH) solution to convert NO and NO2 to MNO2.

Abstract: A system for reducing ammonia (NH3) emissions includes (a) a first component comprising a first substrate containing a three-way catalyst, wherein the first component is disposed upstream of a second component comprising a second substrate containing an ammonia oxidation catalyst, wherein said ammonia oxidation catalyst comprises a small pore molecular sieve supporting at least one transition metal; and (b) an oxygen-containing gas input disposed between the components. For example, a CHA Framework Type small pore molecular sieve may be used. A method for reducing NH3 emission includes introducing an oxygen-containing gas into a gas stream to produce an oxygenated gas stream; and exposing the oxygenated gas stream to an NH3 oxidation catalyst to selectively oxidize at least a portion of the NH3 to N2. The method may further include the step of exposing a rich burn exhaust gas to a three-way catalyst to produce the gas stream comprising NH3.

Abstract: A process of producing degassed liquid sulfur using process gas containing H2S to agitate the liquid sulfur being degassed while in contact with a degassing catalyst. Process gas is less costly and less complicated and quickly accomplishes substantial degassing rendering the liquid sulfur much safer in storage and transportation.

Abstract: Systems and methods for the use of highly reactive hydrated lime (HRH) in circulating dry scrubbers (CDS) to remove sulfur dioxide (SO2) from the flue gas.

Abstract: Systems and methods for synthesizing high-quality nanocrystals via segmented, continuous flow microwave-assisted reactor were developed.