EP1904229A1 - An oxidation catalyst for nh3 and an apparatus for treating slipped or scrippedd nh3 - Google Patents

An oxidation catalyst for nh3 and an apparatus for treating slipped or scrippedd nh3

Info

Publication number
EP1904229A1
EP1904229A1 EP05820593A EP05820593A EP1904229A1 EP 1904229 A1 EP1904229 A1 EP 1904229A1 EP 05820593 A EP05820593 A EP 05820593A EP 05820593 A EP05820593 A EP 05820593A EP 1904229 A1 EP1904229 A1 EP 1904229A1
Authority
EP
European Patent Office
Prior art keywords
ammonia
catalyst
impregnated
zeolite
platinum
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP05820593A
Other languages
German (de)
French (fr)
Other versions
EP1904229A4 (en
Inventor
Hyun-sik 235-902 Sujeong Hanyang HAN
Eun-Seok Kim
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Heesung Catalysts Corp
Original Assignee
Heesung Catalysts Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR1020050092994A external-priority patent/KR100765413B1/en
Application filed by Heesung Catalysts Corp filed Critical Heesung Catalysts Corp
Publication of EP1904229A1 publication Critical patent/EP1904229A1/en
Publication of EP1904229A4 publication Critical patent/EP1904229A4/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B01J23/8926—Copper and noble metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9404—Removing only nitrogen compounds
    • B01D53/9436—Ammonia
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/08—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y
    • B01J29/10—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y containing iron group metals, noble metals or copper
    • B01J29/14—Iron group metals or copper
    • B01J29/146—Y-type faujasite
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65
    • B01J29/72—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65 containing iron group metals, noble metals or copper
    • B01J29/76—Iron group metals or copper
    • B01J29/7615—Zeolite Beta
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
    • B01J35/56—Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0215—Coating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/10—Noble metals or compounds thereof
    • B01D2255/102—Platinum group metals
    • B01D2255/1021—Platinum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/207—Transition metals
    • B01D2255/20761—Copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/50—Zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/30—After treatment, characterised by the means used
    • B01J2229/32—Reaction with silicon compounds, e.g. TEOS, siliconfluoride

Definitions

  • the present invention relates to an ammonia oxidation catalyst and a system for treating slipped ammonia or waste ammonia using the same, and more particularly to an ammonia oxidation catalyst comprising either Cu-containing zeolite impregnated with platinum or Cu/Si-containing alumina impregnated with platinum, which has improved low-temperature activity of oxidizing ammonia generated in a mobile source or fixed source system and is used to inhibit the formation of nitrogen oxides caused by ammonia, as well as a system for the treatment of ammonia contained in vehicle exhaust gas, a chemical reactor system and an environmental device and system, which include said ammonia oxidation catalyst.
  • Background Art
  • NOx generated from systems is generally used in an ammonia preparation process, industrial processes that use ammonia as main raw material or subsidiary raw material, and the fields of multi-purpose boilers, engines, furnaces and vehicle engines.
  • the SCR or selective non-catalytic reduction (SNCR) system is used to reduce the emission of nitrogen oxides from exhaust gas containing NOx, particulate matter and hydrogen carbon, which is discharged from chemical factories, boilers, engines, furnaces, and vehicle engines.
  • reducing agent ammonia in a fixed source SCR system is injected into an exhaust gas stream in an exhaust gas treatment system in which an SCR reduction catalyst bed is disposed.
  • the injected ammonia catalytically reduces a large amount of nitrogen oxide contained in the exhaust gas so as to convert the nitrogen oxide into water and nitrogen. Because the nitrogen oxide removal catalyst used in the SCR system is carefully treated and expensive, it is preferable to control the stoichiometry of exhaust gas/ammonia/catalyst reactions, but there is a problem of secondary contamination due to the slip of ammonia unreacted with NOx. Meanwhile, methods of using a urea or ammonia SCR catalyst to remove nitrogen oxides from the exhaust gas of lean burn engines have been studied, but the problem caused by ammonia slip in vehicles still remains as a problem to be solved, like the problem in the fixed source system.
  • ammonia slip is defined as a phenomenon in which ammonia gas, which is injected for the purpose of reacting with nitrogen oxides contained in exhaust gas discharged from the fixed source or mobile source nitrogen oxide generator, does not participate in an NOx reduction reaction due to various causes, but rather is emitted to the external environment.
  • slipped ammonia is defined to mean ammonia which is slipped and emitted to the external environment.
  • the present invention relates to a catalyst composition, which is effectively used to oxidatively degrade either waste ammonia (NH ) emitted from the fixed source system or ammonia slipped from the fixed source SCR and SNCR systems and the mobile source SCR system into nitrogen (N ) and water (H O) under preferred temperature conditions and, at the same time, to minimize nitrogen oxides caused by side reactions, as well as a system for treating ammonia using the above catalyst composition.
  • NH waste ammonia
  • N nitrogen
  • H O water
  • the catalyst preparation method disclosed in said patent comprises the steps of: alloying the surface layer of a steel material, having an annular shape or honeycomb, with aluminum; subjecting the steel material having the alloy layer to aluminum dissolution using a solution capable of dissolving aluminum, thus making the steel material surface layer porous; oxidizing the steel material according to known processes to obtain a catalyst substrate; dipping the oxidized steel material in a chloroplatinate solution adjusted to weak alkalinity using barium hydroxide; and removing the treated catalyst substrate from the solution, followed by drying.
  • a known exhaust treatment system for use in mobile sources such as diesel engines comprises: (a) an exhaust system through which exhaust gas flows; (b) a selective catalytic reduction catalyst placed in the exhaust system, the catalyst serving to catalyze the reduction of NOx into nitrogen by ammonia and adsorbing and desorbing ammonia during an engine cycle; (c) an ammonia source; (d) a means for supplying ammonia from the ammonia source to the catalyst; and (e) a means for intermittently supplying ammonia during the engine cycle.
  • a system for treating slipped ammonia is not yet disclosed.
  • a known fixed source system for the treatment of exhaust gas comprises: (a) a combustion chamber having no reducing agent-injection unit; (b) a waste heat boiler through which exhaust gas generated in the combustion chamber flows; (c) a dry, semi-dry or wet reaction column; (d) a bag filter; (e) an SCR exhaust treatment system including an ammonia-reducing agent supply unit and a catalyst column; and (f) a means for emitting exhaust gas.
  • a system for treating slipped ammonia is not yet known.
  • a known fixed source NSCR system for the treatment of exhaust gas comprises: (a) a combustion chamber equipped with a reducing agent-injection unit; (b) a waste heat boiler; (c) a reaction column; (d) a bag filter; and (e) a means for emitting exhaust gas.
  • an ammonia treatment system for preventing ammonia, used as a reducing agent, from being emitted to the external environment is not yet known.
  • the present invention aims to provide a system for treating slipped ammonia or waste ammonia generated in a mobile source or fixed source SCR reaction or NSCR reaction, or in ammonia-related processes. Disclosure of Invention Technical Problem
  • Another object of the present invention is to provide an ammonia oxidation catalyst, which can inhibit nitrogen oxide formation caused by an ammonia oxidation reaction.
  • Still another object of the present invention is to apply an ammonia oxidation catalyst having improved low-temperature activity in an exhaust treatment system.
  • the ultimate object of the present invention is to provide an ammonia oxidation catalyst, which is used to minimize the formation of nitrogen oxides caused by slipped ammonia or waste ammonia generated from SCR or NSCR reaction or ammonia-related processes in an mobile source or fixed source system and to effectively remove ammonia under preferred temperature conditions, as well as a system for treating ammonia using the ammonia oxidation catalyst.
  • the above objects can be accomplished by providing a catalyst composition comprising either Cu-containing zeolite impregnated with precious metal (platinum, palladium or rhodium) or Cu/Si-containing alumina impregnated with precious metal, as well as a system for treating ammonia, in which a monolithic ceramic or metal substrate having the composition supported thereon is disposed.
  • the zeolite used in the present invention, is an aluminosilicate zeolite-based natural or synthetic zeolite and is selected from the group consisting of metallic or non- metallic ZSM5, zeolite Y, ⁇ Zeolite, ⁇ zeolite, and mordenite.
  • the metallic zeolite is preferably Fe-zeolite, Cu-zeolite or Fe/Cu-zeolite, which are ion-exchanged with Fe or Cu.
  • the Fe-zeolite may also be impregnated with Cu.
  • the alumina, used in the present invention, is preferably ⁇ alumina, in which Cu and Si are included or impregnated.
  • the precious metal (platinum, palladium or rhodium), used in the present invention, is impregnated in an amount of less than 1.0 wt%.
  • Said catalyst composition may be coated on a catalyst substrate, and all measurement values with respect to the catalyst composition are based on weights after coating the composition on the substrate.
  • Cu When Cu is impregnated into zeolite, Cu can be derived from the following copper compounds. Copper ions from the copper compounds can be divalent or trivalent, and examples of the copper compounds include copper nitrate, copper chloride, copper oxide, copper sulfate, copper oxalate, copper acetate, copper carbonate, copper hydroxide, ammonium copper chloride, ammonium copper hydroxide, ammonium copper phosphate and the like, preferred being copper nitrate or copper acetate. Copper is preferably impregnated in an amount of less than 10 wt% based on the total weight of the catalyst. If copper is impregnated in an amount higher than 10 wt%, no additional increase in the catalyst activity will be shown and no advantage in economical terms will be obtained.
  • the deposition of the catalyst composition on the wall of the substrate made of, for example, monolithic ceramic material or silicon carbide material can be performed using any conventional method.
  • the substrate can be impregnated with the catalyst composition.
  • the catalyst composition can also be wash- coated on the substrate.
  • the present invention relates to an ammonia oxidation catalyst composition
  • an ammonia oxidation catalyst composition comprising either Cu-containing zeolite impregnated with platinum or Cu/ Si-containing alumina impregnated with platinum, and a system for treating ammonia using the same.
  • the inventive catalyst composition has excellent low-temperature activity and can inhibit the formation of nitrogen oxides caused by an ammonia oxidation reaction.
  • the inventive catalyst composition is used to inhibit the formation of nitrogen oxides caused by slipped ammonia or waste ammonia in a mobile source or fixed source SCR reaction or NSCR reaction, ammonia preparation processes or related processes.
  • a substrate having said catalyst supported thereon is placed in the ammonia treatment system.
  • FIGS. 1 and 2 show Cu-containing zeolite Y activity and NOx formation as a function of the content of Pt in the catalyst, respectively.
  • A Cu/ zeolite Y
  • B 0.3 wt% Pt-impregnated Cu/zeolite Y
  • C 0.5 wt% Pt-impregnated Cu/ zeolite Y
  • D 0.7 wt% Pt-impregnated Cu/zeolite Y.
  • FIGS. 3 and 4 show Pt-impregnated Cu/Si-impregnated alumina activity and NOx formation, respectively.
  • E 0.7 wt% Pt-impregnated alumina
  • H 0.7 wt% Pt-impregnated Cu/ Alumina
  • J 0.7 wt% Pt-impregnated Cu/Si alumina.
  • FIGS. 5 and 6 show catalyst activity and NOx formation according to the kind of
  • the present inventors evaluated the suitability of a Cu-containing zeolite catalyst composition and the effect of platinum content on the catalyst composition and, as a result, found that the Cu-containing zeolite alone had a possibility of acting as an ammonia oxidation (hereinafter, also referred to as "AO") catalyst, that the low- temperature activity of the catalyst was increased depending on the platinum content, and also that NOx formation was promoted in proportion to the increase in the platinum content.
  • AO ammonia oxidation
  • the present inventors examined whether alumina capable of substituting for the above-described zeolite was suitable for an AG catalyst composition, and evaluated the effect of Cu contents on the alumina catalyst composition. As a result, it was found that, when alumina was used as the catalyst support, it had AO activity, but was negative in terms of NOx formation, and an increase in the Cu content thereof led to a reduction in activity, but was advantageous in terms of NOx formation.
  • the present inventors examined the suitability of alumina as an AG catalyst according to the content of Si in alumina and, as a result, found that an increase in the content of Si in alumina was advantageous in terms of the formation of NOx formation. Thus, it was found that, when the outlet temperature of NH is maintained at a constant level of about 250 0 C, the alumina catalyst could also be applied.
  • test conditions were as follows: composition of injected gas: 350-390 ppm of NH , 30 ppm of NOx; 5.0% H O, 5.0% O , and a balance of N ; and space velocity: 40,000 1/h.
  • FIGS. 1 and 2 show ammonia conversion and NOx formation, respectively.
  • a conversion rate of 60% was achieved at about 300 0 C, suggesting that Cu-containing zeolite Y can be used as an AO catalyst at high temperatures.
  • an increase in the platinum content thereof led to an improvement in the low-temperature activity thereof, but resulted in an increase in NOx formation.
  • Cu-containing zeolite can be used alone as an AO catalyst, but needs to be impregnated with platinum in order to increase the low- temperature activity thereof.
  • the present inventors evaluated an alumina impregnated with 0.7 wt% platinum, but containing no Cu, a Cu-containing alumina impregnated with 0.7 wt% platinum, and a Cu/Si-containing alumina impregnated with 0.7% platinum, in comparison with Cu-containing zeolite Y impregnated with 0.7 wt% platinum (see FIGS. 3 and 4).
  • the presence of Cu in the catalyst led to a decrease in the low- temperature activity of the catalyst, but was advantageous in terms of the formation of NOx.
  • a result similar to this catalyst was shown for the catalyst containing both Cu and Si.
  • the Cu and Si-containing alumina support was disadvantageous for low- temperature activity compared to zeolite, but showed results similar to those of zeolite with respect to NOx formation.
  • inventive catalyst can be supported on a metal or ceramic honeycomb and be used in an exhaust treatment system for the oxidation of unreacted ammonia contained in exhaust gas emitted from mobile internal combustion engines such as diesel engines and gasoline engines. Also, the inventive catalyst can be used in an exhaust gas treatment system in order to minimize the formation of nitrogen oxides caused by slipped ammonia or waste ammonia generated in an SCR or NSCR system and related processes, including ammonia preparation processes, and to effectively oxidize the ammonia.
  • the inventive catalyst can be used in a mobile source system for the treatment of exhaust gas, such as a diesel engine, which comprises (a) an exhaust system through which exhaust gas flows, (b) a selective catalytic reduction catalyst serving to catalyze the reduction of NOx into nitrogen by ammonia and adsorbing and desorbing ammonia during an engine cycle, (c) an ammonia source, (d) a means for supplying ammonia from the ammonia source to said selective catalytic reduction catalyst, and (e) a means for intermittently supplying ammonia during the engine cycle, wherein an ammonia oxidation catalyst comprising either Cu-containing zeolite impregnated with platinum or Cu-containing alumina impregnated with platinum is supported on a monolithic metal or ceramic substrate and is disposed at a stage following the selective catalytic reduction catalyst.
  • a selective catalytic reduction catalyst serving to catalyze the reduction of NOx into nitrogen by ammonia and adsorbing and desorbing ammonia during an engine cycle
  • the inventive catalyst can be applied in a fixed source SCR system for the treatment of exhaust gas, which comprises (a) a combustion chamber having no reducing agent-injection unit, (b) a waste heat boiler through which exhaust gas generated in the combustion chamber flows, (c) a dry, semi-dry or wet reaction column, (d) a bag filter, (e) an SCR exhaust treatment system including an ammonia- reducing agent supply unit and a catalyst column, and (f) a means for emitting exhaust gas, wherein an ammonia oxidation catalyst comprising either Cu-containing zeolite impregnated with platinum or Cu-containing alumina impregnated with platinum is supported on a monolithic metal or ceramic substrate and is disposed at a stage following the catalyst column.
  • a fixed source SCR system for the treatment of exhaust gas which comprises (a) a combustion chamber having no reducing agent-injection unit, (b) a waste heat boiler through which exhaust gas generated in the combustion chamber flows, (c) a dry, semi-dry or wet reaction column
  • the inventive catalyst can be applied in a fixed source NSCR system for the treatment of exhaust gas, which comprises (a) a combustion chamber equipped with a reducing agent-injection unit, (b) a waste heat boiler, (c) a reaction column, (d) a bag filter, and (e) a means for emitting exhaust gas, wherein an ammonia oxidation catalyst comprising either Cu-containing zeolite impregnated with platinum or Cu- containing alumina impregnated with platinum is supported on a monolithic metal or ceramic substrate and is disposed at a stage following the combustion chamber.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Biomedical Technology (AREA)
  • Health & Medical Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Environmental & Geological Engineering (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
  • Catalysts (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

Disclosed herein are an ammonia oxidation catalyst and a system for treating slipped ammonia or waste ammonia using the oxidation catalyst. More specifically, disclosed are an ammonia oxidation catalyst comprising either Cu-containing zeolite impregnated with platinum or Cu-containing alumina impregnated with platinum, which has improved low-temperature activity to oxidize ammonia generated in a mobile source or fixed source system and is used to inhibit the formation of nitrogen oxides, as well as a system for treating ammonia contained in vehicle exhaust gas, a chemical reactor system and an environmental device and system, which include the oxidation catalyst.

Description

Description
AN OXIDATION CATALYST FOR NH AND AN APPARATUS FOR TREATING SLIPPED OR SCRIPPEDD NH
Technical Field
[1] The present invention relates to an ammonia oxidation catalyst and a system for treating slipped ammonia or waste ammonia using the same, and more particularly to an ammonia oxidation catalyst comprising either Cu-containing zeolite impregnated with platinum or Cu/Si-containing alumina impregnated with platinum, which has improved low-temperature activity of oxidizing ammonia generated in a mobile source or fixed source system and is used to inhibit the formation of nitrogen oxides caused by ammonia, as well as a system for the treatment of ammonia contained in vehicle exhaust gas, a chemical reactor system and an environmental device and system, which include said ammonia oxidation catalyst. Background Art
[2] A selective catalytic reduction (SCR) system for the control of nitrogen oxides
(NOx) generated from systems is generally used in an ammonia preparation process, industrial processes that use ammonia as main raw material or subsidiary raw material, and the fields of multi-purpose boilers, engines, furnaces and vehicle engines. The SCR or selective non-catalytic reduction (SNCR) system is used to reduce the emission of nitrogen oxides from exhaust gas containing NOx, particulate matter and hydrogen carbon, which is discharged from chemical factories, boilers, engines, furnaces, and vehicle engines. Generally, reducing agent ammonia in a fixed source SCR system is injected into an exhaust gas stream in an exhaust gas treatment system in which an SCR reduction catalyst bed is disposed. The injected ammonia catalytically reduces a large amount of nitrogen oxide contained in the exhaust gas so as to convert the nitrogen oxide into water and nitrogen. Because the nitrogen oxide removal catalyst used in the SCR system is carefully treated and expensive, it is preferable to control the stoichiometry of exhaust gas/ammonia/catalyst reactions, but there is a problem of secondary contamination due to the slip of ammonia unreacted with NOx. Meanwhile, methods of using a urea or ammonia SCR catalyst to remove nitrogen oxides from the exhaust gas of lean burn engines have been studied, but the problem caused by ammonia slip in vehicles still remains as a problem to be solved, like the problem in the fixed source system. As used herein, the term "ammonia slip" is defined as a phenomenon in which ammonia gas, which is injected for the purpose of reacting with nitrogen oxides contained in exhaust gas discharged from the fixed source or mobile source nitrogen oxide generator, does not participate in an NOx reduction reaction due to various causes, but rather is emitted to the external environment. The term "slipped ammonia" is defined to mean ammonia which is slipped and emitted to the external environment. Meanwhile, separate from the problem of ammonia slip, the need to improve technology for the removal of waste ammonia gas has also been noted in an ammonia preparation process, industrial processes that use ammonia as main raw material or subsidiary raw material, and an industrial field in which ammonia gas is emitted as a byproduct of other chemical processes.
[3] The present invention relates to a catalyst composition, which is effectively used to oxidatively degrade either waste ammonia (NH ) emitted from the fixed source system or ammonia slipped from the fixed source SCR and SNCR systems and the mobile source SCR system into nitrogen (N ) and water (H O) under preferred temperature conditions and, at the same time, to minimize nitrogen oxides caused by side reactions, as well as a system for treating ammonia using the above catalyst composition.
[4] In a catalytic reaction for ammonia oxidation, the activity and life cycle of the catalyst are always problematic, but pressure loss caused by the shape of the catalyst is also a great problem. Thus, when a large amount of gas is treated, as in the case of exhaust gas treatment, there is significant pressure loss, which results in an increase in the power consumption of blowers and the like, thus increasing operational costs. In an attempt to solve this pressure loss problem, the prior art (Korean Patent Publication No. 1981-1294) relating to ammonia oxidation catalysts discloses a method of preparing an oxidation catalyst showing excellent strength without causing the pressure loss problem, the oxidation catalyst being prepared by making the surface layer of a steel material, having a given shape such as an annular shape, honeycomb shape or plate shape, porous, oxidizing the steel material having the porous surface to obtain a catalyst substrate, and supporting platinum on the catalyst substrate. According to the disclosure of said patent, an aqueous chloroplatinate solution is most suitable as a dipping solution for use in supporting platinum on the catalyst substrate. Specifically, the catalyst preparation method disclosed in said patent comprises the steps of: alloying the surface layer of a steel material, having an annular shape or honeycomb, with aluminum; subjecting the steel material having the alloy layer to aluminum dissolution using a solution capable of dissolving aluminum, thus making the steel material surface layer porous; oxidizing the steel material according to known processes to obtain a catalyst substrate; dipping the oxidized steel material in a chloroplatinate solution adjusted to weak alkalinity using barium hydroxide; and removing the treated catalyst substrate from the solution, followed by drying.
[5] However, it was found that the known ammonia oxidation catalyst has insufficient low-temperature activity and also cannot efficiently inhibit NOx produced in side reactions. [6] Although exhaust gas treatment systems for diesel engines or gasoline engines are known, an example of application of the NH oxidation catalyst according to the present invention to a system is not yet known.
[7] A known exhaust treatment system for use in mobile sources such as diesel engines comprises: (a) an exhaust system through which exhaust gas flows; (b) a selective catalytic reduction catalyst placed in the exhaust system, the catalyst serving to catalyze the reduction of NOx into nitrogen by ammonia and adsorbing and desorbing ammonia during an engine cycle; (c) an ammonia source; (d) a means for supplying ammonia from the ammonia source to the catalyst; and (e) a means for intermittently supplying ammonia during the engine cycle. With respect to the exhaust treatment system in the mobile sources, a system for treating slipped ammonia is not yet disclosed.
[8] Also, a known fixed source system for the treatment of exhaust gas comprises: (a) a combustion chamber having no reducing agent-injection unit; (b) a waste heat boiler through which exhaust gas generated in the combustion chamber flows; (c) a dry, semi-dry or wet reaction column; (d) a bag filter; (e) an SCR exhaust treatment system including an ammonia-reducing agent supply unit and a catalyst column; and (f) a means for emitting exhaust gas. However, with respect to the fixed source SCR exhaust gas treatment system, a system for treating slipped ammonia is not yet known.
[9] Meanwhile, a known fixed source NSCR system for the treatment of exhaust gas comprises: (a) a combustion chamber equipped with a reducing agent-injection unit; (b) a waste heat boiler; (c) a reaction column; (d) a bag filter; and (e) a means for emitting exhaust gas. With respect to the fixed source NSCR system for the treatment of exhaust gas, an ammonia treatment system for preventing ammonia, used as a reducing agent, from being emitted to the external environment is not yet known.
[10] Thus, the present invention aims to provide a system for treating slipped ammonia or waste ammonia generated in a mobile source or fixed source SCR reaction or NSCR reaction, or in ammonia-related processes. Disclosure of Invention Technical Problem
[11] It is an object of the present invention to provide an ammonia oxidation catalyst having improved low-temperature activity in ammonia oxidation reaction.
[12] Another object of the present invention is to provide an ammonia oxidation catalyst, which can inhibit nitrogen oxide formation caused by an ammonia oxidation reaction.
[13] Still another object of the present invention is to apply an ammonia oxidation catalyst having improved low-temperature activity in an exhaust treatment system.
[14] Thus, the ultimate object of the present invention is to provide an ammonia oxidation catalyst, which is used to minimize the formation of nitrogen oxides caused by slipped ammonia or waste ammonia generated from SCR or NSCR reaction or ammonia-related processes in an mobile source or fixed source system and to effectively remove ammonia under preferred temperature conditions, as well as a system for treating ammonia using the ammonia oxidation catalyst. Technical Solution
[15] According to the present invention, the above objects can be accomplished by providing a catalyst composition comprising either Cu-containing zeolite impregnated with precious metal (platinum, palladium or rhodium) or Cu/Si-containing alumina impregnated with precious metal, as well as a system for treating ammonia, in which a monolithic ceramic or metal substrate having the composition supported thereon is disposed.
[16] The zeolite, used in the present invention, is an aluminosilicate zeolite-based natural or synthetic zeolite and is selected from the group consisting of metallic or non- metallic ZSM5, zeolite Y, β Zeolite, γzeolite, and mordenite. The metallic zeolite is preferably Fe-zeolite, Cu-zeolite or Fe/Cu-zeolite, which are ion-exchanged with Fe or Cu. The Fe-zeolite may also be impregnated with Cu. The alumina, used in the present invention, is preferably γ alumina, in which Cu and Si are included or impregnated. The precious metal (platinum, palladium or rhodium), used in the present invention, is impregnated in an amount of less than 1.0 wt%. Said catalyst composition may be coated on a catalyst substrate, and all measurement values with respect to the catalyst composition are based on weights after coating the composition on the substrate.
[17] When Cu is impregnated into zeolite, Cu can be derived from the following copper compounds. Copper ions from the copper compounds can be divalent or trivalent, and examples of the copper compounds include copper nitrate, copper chloride, copper oxide, copper sulfate, copper oxalate, copper acetate, copper carbonate, copper hydroxide, ammonium copper chloride, ammonium copper hydroxide, ammonium copper phosphate and the like, preferred being copper nitrate or copper acetate. Copper is preferably impregnated in an amount of less than 10 wt% based on the total weight of the catalyst. If copper is impregnated in an amount higher than 10 wt%, no additional increase in the catalyst activity will be shown and no advantage in economical terms will be obtained.
[18] The deposition of the catalyst composition on the wall of the substrate made of, for example, monolithic ceramic material or silicon carbide material, can be performed using any conventional method. For example, the substrate can be impregnated with the catalyst composition. Alternatively, the catalyst composition can also be wash- coated on the substrate. Advantageous Effects
[19] The present invention relates to an ammonia oxidation catalyst composition comprising either Cu-containing zeolite impregnated with platinum or Cu/ Si-containing alumina impregnated with platinum, and a system for treating ammonia using the same. The inventive catalyst composition has excellent low-temperature activity and can inhibit the formation of nitrogen oxides caused by an ammonia oxidation reaction. Specifically, the inventive catalyst composition is used to inhibit the formation of nitrogen oxides caused by slipped ammonia or waste ammonia in a mobile source or fixed source SCR reaction or NSCR reaction, ammonia preparation processes or related processes. Also, in the ammonia treatment system, a substrate having said catalyst supported thereon is placed.
Brief Description of the Drawings
[20] FIGS. 1 and 2 show Cu-containing zeolite Y activity and NOx formation as a function of the content of Pt in the catalyst, respectively. In FIGS. 1 and 2, A: Cu/ zeolite Y; B: 0.3 wt% Pt-impregnated Cu/zeolite Y; C: 0.5 wt% Pt-impregnated Cu/ zeolite Y; and D: 0.7 wt% Pt-impregnated Cu/zeolite Y.
[21] FIGS. 3 and 4 show Pt-impregnated Cu/Si-impregnated alumina activity and NOx formation, respectively. In FIGS. 3 and 4, E: 0.7 wt% Pt-impregnated alumina; H: 0.7 wt% Pt-impregnated Cu/ Alumina; and J: 0.7 wt% Pt-impregnated Cu/Si alumina.
[22] FIGS. 5 and 6 show catalyst activity and NOx formation according to the kind of
Pt-impregnated Cu-containing zeolite, respectively. In FIGS. 5 and 6, L: 0.7 wt% Pt- impregnated Cu/Fe-Beta (S); O: 0.7 wt% Pt-impregnated Cu/H-Beta (Z); Q: 0.7 wt% Pt-impregnated Cu/ZSM-5; S: 0.7 wt% Pt-impregnated Cu/H-Beta; and U: 0.7 wt% Pt- impregnated Cu/Fe-Beta. Best Mode for Carrying Out the Invention
[23] Hereinafter, a process for designing a catalyst according to the present invention will be described.
[24] First, the present inventors evaluated the suitability of a Cu-containing zeolite catalyst composition and the effect of platinum content on the catalyst composition and, as a result, found that the Cu-containing zeolite alone had a possibility of acting as an ammonia oxidation (hereinafter, also referred to as "AO") catalyst, that the low- temperature activity of the catalyst was increased depending on the platinum content, and also that NOx formation was promoted in proportion to the increase in the platinum content.
[25] Then, the present inventors examined whether alumina capable of substituting for the above-described zeolite was suitable for an AG catalyst composition, and evaluated the effect of Cu contents on the alumina catalyst composition. As a result, it was found that, when alumina was used as the catalyst support, it had AO activity, but was negative in terms of NOx formation, and an increase in the Cu content thereof led to a reduction in activity, but was advantageous in terms of NOx formation.
[26] On the basis of these findings, the present inventors examined the suitability of alumina as an AG catalyst according to the content of Si in alumina and, as a result, found that an increase in the content of Si in alumina was advantageous in terms of the formation of NOx formation. Thus, it was found that, when the outlet temperature of NH is maintained at a constant level of about 250 0C, the alumina catalyst could also be applied.
[27] However, when the outlet condition of NH in catalyst application sites is not constant, as in vehicles, it is difficult to apply the alumina catalyst support, and thus it is believed that the zeolite catalyst support will be advantageous in wide temperature ranges in terms of AO activity and NOx formation. Also, in selecting zeolite as the catalyst support, the present inventors examined the suitability of zeolite for an AG catalyst according to the Cu content and the type of zeolite, and thus suggested an optimized catalyst composition according to the present invention.
[28] Evaluation tests in all Examples below were conducted under the same conditions.
The test conditions were as follows: composition of injected gas: 350-390 ppm of NH , 30 ppm of NOx; 5.0% H O, 5.0% O , and a balance of N ; and space velocity: 40,000 1/h.
[29] First, Cu-containing-zeolite Y was examined for whether it shows activity suitable for ammonia oxidation. Also, Cu-containing-zeolite Y impregnated with Pt was examined to determine its ammonia oxidation rate at low temperature, and the effect of Pt content on NOx formation.
[30] Said evaluation test was conducted on Cu-containing zeolite Y, and Cu-containing zeolite Y catalysts impregnated with each of 0.3 wt%, 0.5 wt% and 0.7 wt%. FIGS. 1 and 2 show ammonia conversion and NOx formation, respectively. In the case of Cu- containing zeolite Y, a conversion rate of 60% was achieved at about 300 0C, suggesting that Cu-containing zeolite Y can be used as an AO catalyst at high temperatures. Also, it could be found that an increase in the platinum content thereof led to an improvement in the low-temperature activity thereof, but resulted in an increase in NOx formation. This suggests that Cu-containing zeolite can be used alone as an AO catalyst, but needs to be impregnated with platinum in order to increase the low- temperature activity thereof.
[31] In order to find a suitable Cu content and an alternative support on the basis of the above results, the present inventors evaluated an alumina impregnated with 0.7 wt% platinum, but containing no Cu, a Cu-containing alumina impregnated with 0.7 wt% platinum, and a Cu/Si-containing alumina impregnated with 0.7% platinum, in comparison with Cu-containing zeolite Y impregnated with 0.7 wt% platinum (see FIGS. 3 and 4). The presence of Cu in the catalyst led to a decrease in the low- temperature activity of the catalyst, but was advantageous in terms of the formation of NOx. A result similar to this catalyst was shown for the catalyst containing both Cu and Si. The Cu and Si-containing alumina support was disadvantageous for low- temperature activity compared to zeolite, but showed results similar to those of zeolite with respect to NOx formation.
[32] On the basis of the above results, in order to analyze the qualitative properties of zeolite as a support in consideration of low-temperature activity and NOx formation inhibition, the present inventors conducted evaluations on ZSM5, H-beta and Fe-beta zeolites, each impregnated with 0.7 wt% platinum and containing Cu, under the same conditions, with reference to 0.7 wt% platinum-impregnated Cu-containing zeolite Y (see FIGS. 5 and 6). As a result, it was found that an increase in SAR ratio (silica/alumina ratio) led to a decrease in ammonia oxidation activity, and zeolite-beta, particularly Fe-beta, was more advantageous for low-temperature activity than zeolite Y and ZSM5. Also, the inclusion of Cu in the catalyst provided a clear effect of inhibiting NOx formation. In addition, the Cu-containing Fe-beta zeolite was a catalyst for the oxidative degradation of ammonia, which had excellent low-temperature activity and could effectively inhibit NOx caused by side reactions. Mode for the Invention
[33] The above-described inventive catalyst can be supported on a metal or ceramic honeycomb and be used in an exhaust treatment system for the oxidation of unreacted ammonia contained in exhaust gas emitted from mobile internal combustion engines such as diesel engines and gasoline engines. Also, the inventive catalyst can be used in an exhaust gas treatment system in order to minimize the formation of nitrogen oxides caused by slipped ammonia or waste ammonia generated in an SCR or NSCR system and related processes, including ammonia preparation processes, and to effectively oxidize the ammonia.
[34] Specifically, the inventive catalyst can be used in a mobile source system for the treatment of exhaust gas, such as a diesel engine, which comprises (a) an exhaust system through which exhaust gas flows, (b) a selective catalytic reduction catalyst serving to catalyze the reduction of NOx into nitrogen by ammonia and adsorbing and desorbing ammonia during an engine cycle, (c) an ammonia source, (d) a means for supplying ammonia from the ammonia source to said selective catalytic reduction catalyst, and (e) a means for intermittently supplying ammonia during the engine cycle, wherein an ammonia oxidation catalyst comprising either Cu-containing zeolite impregnated with platinum or Cu-containing alumina impregnated with platinum is supported on a monolithic metal or ceramic substrate and is disposed at a stage following the selective catalytic reduction catalyst.
[35] Also, the inventive catalyst can be applied in a fixed source SCR system for the treatment of exhaust gas, which comprises (a) a combustion chamber having no reducing agent-injection unit, (b) a waste heat boiler through which exhaust gas generated in the combustion chamber flows, (c) a dry, semi-dry or wet reaction column, (d) a bag filter, (e) an SCR exhaust treatment system including an ammonia- reducing agent supply unit and a catalyst column, and (f) a means for emitting exhaust gas, wherein an ammonia oxidation catalyst comprising either Cu-containing zeolite impregnated with platinum or Cu-containing alumina impregnated with platinum is supported on a monolithic metal or ceramic substrate and is disposed at a stage following the catalyst column. Industrial Applicability
[36] In addition, the inventive catalyst can be applied in a fixed source NSCR system for the treatment of exhaust gas, which comprises (a) a combustion chamber equipped with a reducing agent-injection unit, (b) a waste heat boiler, (c) a reaction column, (d) a bag filter, and (e) a means for emitting exhaust gas, wherein an ammonia oxidation catalyst comprising either Cu-containing zeolite impregnated with platinum or Cu- containing alumina impregnated with platinum is supported on a monolithic metal or ceramic substrate and is disposed at a stage following the combustion chamber.

Claims

Claims
[1] An ammonia oxidation catalyst comprising either Cu-containing zeolite impregnated with platinum or Cu-containing alumina impregnated with platinum.
[2] The ammonia oxidation catalyst of Claim 1, wherein the zeolite is beta zeolite.
[3] The ammonia oxidation catalyst of Claim 2, wherein the beta-zeolite is Fe-beta zeolite.
[4] The ammonia oxidation catalyst of Claim 1, wherein the alumina is further impregnated with Si.
[5] The ammonia oxidation catalyst of any one of Claims 1 to 3, wherein the zeolite is a zeolite impregnated with less than 1.0 wt% platinum and containing less than 10 wt% copper.
[6] A mobile source system for the treatment of exhaust gas, which comprises (a) an exhaust system through which exhaust gas flows, (b) a selective catalytic reduction catalyst serving to catalyze the reduction of NOx into nitrogen by ammonia and adsorbing and desorbing ammonia during an engine cycle, (c) an ammonia source, (d) a means for supplying ammonia from the ammonia source to said selective catalytic reduction catalyst, and (e) a means for intermittently supplying ammonia during the engine cycle, wherein an ammonia oxidation catalyst comprising either Cu-containing zeolite impregnated with platinum or Cu-containing alumina impregnated with platinum according to Claim 1 is supported on a monolithic metal or ceramic substrate and disposed at a stage following the selective catalytic reduction catalyst.
[7] A fixed source SCR system for the treatment of exhaust gas, which comprises (a) a combustion chamber having no reducing agent-injection unit, (b) a waste heat boiler through which exhaust gas generated in the combustion chamber flows, (c) a dry, semi-dry or wet reaction column, (d) a bag filter, (e) an SCR exhaust treatment system including an ammonia-reducing agent supply unit and a catalyst column, and (f) a means for emitting exhaust gas, wherein an ammonia oxidation catalyst comprising either Cu-containing zeolite impregnated with platinum or Cu-containing alumina impregnated with platinum according to Claim 1 is supported on a monolithic metal or ceramic substrate and disposed at a stage following the catalyst column.
[8] A fixed source NSCR system for the treatment of exhaust gas, which comprises
(a) a combustion chamber equipped with a reducing agent-injection unit, (b) a waste heat boiler, (c) a reaction column, (d) a bag filter, and (e) a means for emitting exhaust gas, wherein an ammonia oxidation catalyst comprising either Cu-containing zeolite impregnated with platinum or Cu-containing alumina im- pregnated with platinum according to Claim 1 is supported on a monolithic metal or ceramic substrate and disposed at a stage following the combustion chamber.
EP05820593.1A 2005-07-06 2005-11-07 An oxidation catalyst for nh3 and an apparatus for treating slipped or scrippedd nh3 Withdrawn EP1904229A4 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
KR20050060930 2005-07-06
KR1020050092994A KR100765413B1 (en) 2005-07-06 2005-10-04 An oxidation catalyst for NH3 and an apparatus for treating slipped or scrippedd NH3
PCT/KR2005/003750 WO2007004774A1 (en) 2005-07-06 2005-11-07 An oxidation catalyst for nh3 and an apparatus for treating slipped or scrippedd nh3

Publications (2)

Publication Number Publication Date
EP1904229A1 true EP1904229A1 (en) 2008-04-02
EP1904229A4 EP1904229A4 (en) 2014-04-16

Family

ID=37604614

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05820593.1A Withdrawn EP1904229A4 (en) 2005-07-06 2005-11-07 An oxidation catalyst for nh3 and an apparatus for treating slipped or scrippedd nh3

Country Status (2)

Country Link
EP (1) EP1904229A4 (en)
WO (1) WO2007004774A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160101413A1 (en) * 2011-04-08 2016-04-14 Johnson Matthey Public Limited Company Catalysts for the reduction of ammonia emission from rich-burn exhaust

Families Citing this family (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7771669B2 (en) 2006-03-20 2010-08-10 Ford Global Technologies, Llc Soot oxidation catalyst and method of making
US7998423B2 (en) 2007-02-27 2011-08-16 Basf Corporation SCR on low thermal mass filter substrates
AR065501A1 (en) 2007-02-27 2009-06-10 Basf Catalysts Llc ZEOLITA CHA COPPER CATALYSTS
CN101711185A (en) * 2007-02-27 2010-05-19 巴斯夫催化剂公司 bifunctional catalysts for selective ammonia oxidation
EP2517773B2 (en) 2007-04-26 2019-08-07 Johnson Matthey Public Limited Company Copper/LEV-zeolite SCR catalyst
US7727499B2 (en) * 2007-09-28 2010-06-01 Basf Catalysts Llc Ammonia oxidation catalyst for power utilities
US20090180943A1 (en) * 2008-01-16 2009-07-16 Basf Catalysts Llc Selective Ammonia Oxidation Catalysts
US20090196812A1 (en) 2008-01-31 2009-08-06 Basf Catalysts Llc Catalysts, Systems and Methods Utilizing Non-Zeolitic Metal-Containing Molecular Sieves Having the CHA Crystal Structure
BRPI0912247B1 (en) 2008-05-07 2019-04-16 Umicore Ag & Co. Kg PROCESS FOR REDUCING NITROGEN OXIDE IN EXHAUST GASES CONTAINING HYDROCARBONS BY EMPLOYING A SCR CATALYST ON THE BASIS OF A MOLECULAR SCREEN.
EP3473825A1 (en) 2008-06-27 2019-04-24 Umicore Ag & Co. Kg Method and device for cleaning diesel exhaust gases
NL2001788C2 (en) * 2008-07-11 2010-01-12 Stichting Energie Process for the decomposition of N2O, catalyst for it and preparation of this catalyst.
KR100962082B1 (en) 2008-07-31 2010-06-09 희성촉매 주식회사 Catalysts for NOx reduction employing H2 and a method of reducing NOx
KR101011760B1 (en) * 2008-08-05 2011-02-07 희성촉매 주식회사 Novel SCR catalysts and after-treatment devices for diesel engine exhaust gas
US10632423B2 (en) * 2008-11-03 2020-04-28 Basf Corporation Bimetallic catalysts for selective ammonia oxidation
US10583424B2 (en) 2008-11-06 2020-03-10 Basf Corporation Chabazite zeolite catalysts having low silica to alumina ratios
US8293198B2 (en) 2009-12-18 2012-10-23 Basf Corporation Process of direct copper exchange into Na+-form of chabazite molecular sieve, and catalysts, systems and methods
US8293199B2 (en) 2009-12-18 2012-10-23 Basf Corporation Process for preparation of copper containing molecular sieves with the CHA structure, catalysts, systems and methods
KR101631149B1 (en) 2010-04-21 2016-06-20 희성촉매 주식회사 Diesel engine exhaust gas purification device having ammonia decomposition module
US8658560B1 (en) 2012-10-15 2014-02-25 Heesung Catalysts Corporation Hydrogenation catalyst for nitro-aromatic compounds and method for preparing the same
CN115445654B (en) * 2022-09-21 2024-02-02 中国科学院生态环境研究中心 Molecular sieve catalyst for purifying ammonia in tail gas of diesel vehicle, preparation method and application

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5409671A (en) * 1991-12-26 1995-04-25 Mazda Motor Corporation Catalytic converter for treating exhaust gas
EP0773057A1 (en) * 1995-11-09 1997-05-14 Toyota Jidosha Kabushiki Kaisha Exhaust gas purifying catalyst
US20040156771A1 (en) * 2003-02-10 2004-08-12 Nissan Motor Co., Ltd. Method of reducing carbon monoxide concentration
EP1872852A1 (en) * 2005-03-30 2008-01-02 Sued-Chemie Catalysts Japan, Inc. Ammonia decomposition catalyst and process for decomposition of ammonia using the catalyst

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5244852A (en) * 1988-11-18 1993-09-14 Corning Incorporated Molecular sieve-palladium-platinum catalyst on a substrate
US5024981A (en) * 1989-04-20 1991-06-18 Engelhard Corporation Staged metal-promoted zeolite catalysts and method for catalytic reduction of nitrogen oxides using the same
DE10054877A1 (en) * 2000-11-06 2002-05-29 Omg Ag & Co Kg Exhaust gas cleaning system for the selective catalytic reduction of nitrogen oxides under lean exhaust gas conditions and methods for exhaust gas cleaning
US7438878B2 (en) * 2001-03-12 2008-10-21 Basf Catalysts Llc Selective catalytic reduction of N2O
JP4439872B2 (en) * 2003-10-30 2010-03-24 財団法人地球環境産業技術研究機構 Method for producing zeolite catalyst for water treatment

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5409671A (en) * 1991-12-26 1995-04-25 Mazda Motor Corporation Catalytic converter for treating exhaust gas
EP0773057A1 (en) * 1995-11-09 1997-05-14 Toyota Jidosha Kabushiki Kaisha Exhaust gas purifying catalyst
US20040156771A1 (en) * 2003-02-10 2004-08-12 Nissan Motor Co., Ltd. Method of reducing carbon monoxide concentration
EP1872852A1 (en) * 2005-03-30 2008-01-02 Sued-Chemie Catalysts Japan, Inc. Ammonia decomposition catalyst and process for decomposition of ammonia using the catalyst

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2007004774A1 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160101413A1 (en) * 2011-04-08 2016-04-14 Johnson Matthey Public Limited Company Catalysts for the reduction of ammonia emission from rich-burn exhaust
US9757719B2 (en) * 2011-04-08 2017-09-12 Johnson Matthey Public Limited Company Catalysts for the reduction of ammonia emission from rich-burn exhaust

Also Published As

Publication number Publication date
EP1904229A4 (en) 2014-04-16
WO2007004774A1 (en) 2007-01-11

Similar Documents

Publication Publication Date Title
US20090126353A1 (en) Oxidation Catalyst for NH3 and an Apparatus for Treating Slipped or Scripped NH3
WO2007004774A1 (en) An oxidation catalyst for nh3 and an apparatus for treating slipped or scrippedd nh3
EP1967264B1 (en) Denitrification catalyst, optionally coated on a honeycomb structure carrier, and method of exhaust gas denitrification with the same
EP2113296A2 (en) Exhaust gas purification method using selective reduction catalyst
JP4745968B2 (en) Denitration catalyst with excellent low temperature characteristics
EP2656913B1 (en) a method for manufacturing a catalyst comprising Copper cha zeolite catalysts
EP2785452B1 (en) Catalyst for treating exhaust gas
EP2659974B1 (en) Selective reduction catalyst, and exhaust gas purification device and exhaust gas purification method using same
US20120328499A1 (en) Exhaust gas purification catalyst apparatus using selective reduction-type catalyst and exhaust gas purification method
EP3674524A1 (en) Integrated scr and amox catalyst systems
KR20160079935A (en) Bifunctional catalysts for selective ammonia oxidation
WO2015017516A2 (en) Ammonia slip catalyst
JP2005177570A (en) Scr catalyst excellent in characteristic at high temperature
CA2464567C (en) Exhaust gas purifying catalyst and process for purifying exhaust gas by use of the catalyst
US11225895B2 (en) Catalyst article for use in an emission treatment system
CA2795522A1 (en) Fe-bea/fe-mfi mixed zeolite catalyst and process for treating nox in gas streams using the same
WO2018065353A1 (en) Catalyst article and method for the abatement of ammonia and nitrogen oxides
US20240066468A1 (en) Exhaust gas treatment system
JPH11324663A (en) Catalyst for controlling of exhaust gas emission
JPH0724257A (en) Production of denitrating agent

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20080206

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR IT

RBV Designated contracting states (corrected)

Designated state(s): DE FR IT

DAX Request for extension of the european patent (deleted)
RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: HEESUNG CATALYSTS CORPORATION

A4 Supplementary search report drawn up and despatched

Effective date: 20140317

RIC1 Information provided on ipc code assigned before grant

Ipc: B01J 29/068 20060101ALI20140311BHEP

Ipc: B01J 29/072 20060101AFI20140311BHEP

Ipc: B01J 23/72 20060101ALI20140311BHEP

Ipc: B01J 23/42 20060101ALI20140311BHEP

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20141014