WO2013146729A1 - Method for cleaning discharged combustion gas, and denitration catalyst - Google Patents

Method for cleaning discharged combustion gas, and denitration catalyst Download PDF

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WO2013146729A1
WO2013146729A1 PCT/JP2013/058683 JP2013058683W WO2013146729A1 WO 2013146729 A1 WO2013146729 A1 WO 2013146729A1 JP 2013058683 W JP2013058683 W JP 2013058683W WO 2013146729 A1 WO2013146729 A1 WO 2013146729A1
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denitration catalyst
exhaust gas
type zeolite
cobalt
catalyst
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PCT/JP2013/058683
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French (fr)
Japanese (ja)
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香奈 清水
日数谷　進
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日立造船株式会社
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    • 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
    • B01J29/18—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type
    • 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
    • B01D53/9409—Nitrogen oxides
    • B01D53/9413—Processes characterised by a specific catalyst
    • B01D53/9418—Processes characterised by a specific catalyst for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
    • 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
    • B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/208—Hydrocarbons
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/202—Alkali metals
    • B01D2255/2022—Potassium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/202—Alkali metals
    • B01D2255/2027—Sodium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/204—Alkaline earth metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/204—Alkaline earth metals
    • B01D2255/2042—Barium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/204—Alkaline earth metals
    • B01D2255/2045—Calcium
    • 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
    • B01D2255/20746—Cobalt
    • 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
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/50—Zeolites
    • B01D2255/504—ZSM 5 zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/45—Gas separation or purification devices adapted for specific applications
    • B01D2259/4566—Gas separation or purification devices adapted for specific applications for use in transportation means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2510/00—Surface coverings
    • F01N2510/06—Surface coverings for exhaust purification, e.g. catalytic reaction
    • F01N2510/063—Surface coverings for exhaust purification, e.g. catalytic reaction zeolites
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/03—Adding substances to exhaust gases the substance being hydrocarbons, e.g. engine fuel
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the present invention relates to a purification method for removing nitrogen oxides from combustion exhaust gas, and a denitration catalyst.
  • the method of removing nitrogen oxides (NOx) contained in combustion exhaust gas is to contact a gas obtained by adding ammonia (NH 3 ) as a reducing agent to exhaust gas and contacting a denitration catalyst mainly composed of vanadium or titania.
  • NH 3 ammonia
  • SCR selective catalytic reduction
  • the operating temperature of the denitration facility when sulfur oxide is present must be equal to or higher than the precipitation temperature of ammonium sulfate from the viewpoint of preventing the precipitation of ammonium sulfate on the catalyst.
  • the precipitation temperature of ammonium sulfate is related to the sulfur trioxide (SO 3 ) concentration and ammonia (NH 3 ) concentration in the exhaust gas. When the SO 3 concentration and the NH 3 concentration increase, the precipitation temperature of ammonium sulfate increases.
  • the SOx concentration is generally 100 ppm
  • the SO 3 concentration is 10% of that 10 ppm
  • the NOx concentration is 500 ppm, so it is used as a reducing agent.
  • the NH 3 concentration is a maximum of 400 ppm.
  • the precipitation temperature of ammonium sulfate under this condition is about 250 ° C.
  • the coal-fired boiler exhaust gas temperature is 300 to 400 ° C., which is higher than the ammonium sulfate precipitation temperature of 250 ° C., so that ammonium sulfate does not precipitate on the catalyst and stable catalyst performance can be maintained.
  • the SOx concentration in the exhaust gas is 600 ppm and the NOx concentration is 1000 ppm.
  • the NH 3 concentration used as the reducing agent is a maximum of 800 ppm. Accordingly, the precipitation temperature of ammonium sulfate at this time is about 280 ° C.
  • the exhaust gas temperature for ships is 300 ° C. or lower, usually about 250 ° C., so that ammonium sulfate is precipitated under these conditions, and stable catalyst performance cannot be maintained.
  • the precipitation temperature of ammonium sulfate is set to the exhaust gas temperature.
  • the precipitation temperature of ammonium sulfate is determined by the SO 3 concentration and the NH 3 concentration. Since the NH 3 concentration is determined by the NOx concentration in the exhaust gas and the target denitration rate, this value cannot be reduced.
  • Patent Document 1 nitrogen oxides, particularly NO, contained in exhaust gas discharged from an internal combustion engine can be directly decomposed, and oxygen (O 2 ) generated by the decomposition and coexist in the exhaust gas.
  • a nitrogen oxide purification catalyst with a very small reduction in catalytic activity due to oxygen (O 2 ) a nitrogen oxide purification catalyst comprising a rare earth oxide or a rare earth composite oxide having a cubic C-type structure is disclosed.
  • the exhaust gas purification method by the direct decomposition method using the nitrogen oxide purification catalyst described in Patent Document 1 has a problem that the reaction temperature for exhaust gas purification is as high as 600 ° C. or higher.
  • a catalyst in which a transition metal is supported on zeolite is effective for the reduction and removal reaction of NOx using hydrocarbons as a reducing agent.
  • Patent Document 2 discloses an exhaust gas purification method using a catalyst having a denitration performance that removes nitrogen oxide (NOx) even in exhaust gas containing sulfur oxide, and iron, cobalt, silver as a denitration catalyst.
  • Exhaust gas that reduces and removes nitrogen oxides NOx in exhaust gas by contacting ⁇ -zeolite supporting molybdenum or tungsten with oxygen-exhaust exhaust gas in the presence of ethanol and / or isopropyl alcohol as a reducing agent A purification method is described.
  • Patent Document 3 proton-type ⁇ zeolite is used as a catalyst, and oxygen-excess exhaust gas is contacted in the presence of ethanol and / or isopropyl alcohol as a reducing agent to reduce nitrogen oxide NOx in the exhaust gas.
  • An exhaust gas purification method to be removed is described.
  • Na-ZSM-5 zeolite or H-ZSM-5 type zeolite having a SiO 2 / Al 2 O 3 ratio of 27 or more and 100 or less is used as a catalyst carrier, and the catalyst carrier is a cobalt salt aqueous solution.
  • An exhaust gas purification method is described in which type zeolite is used as a denitration catalyst and liquefied petroleum gas having a composition of propane and butane is used as the reducing agent.
  • the object of the present invention is to solve the above-mentioned problems of the prior art, in which high concentrations of nitrogen oxides (NOx) and sulfur oxides (SOx) exist, and the exhaust gas temperature is as low as 300 ° C. or lower, for example, marine engines.
  • An object of the present invention is to provide a method for purifying combustion exhaust gas and a denitration catalyst that can effectively reduce nitrogen oxides from the combustion exhaust gas discharged from the exhaust gas.
  • the inventors of the present invention have obtained a combustion exhaust gas to which alcohol has been added as a reducing agent on a catalyst in which cobalt (Co) is supported on sodium-type zeolite at a temperature of 300 ° C. or lower. It has been found that the nitrogen oxide can be effectively reduced from the combustion exhaust gas by bringing it into contact, and the present invention has been completed.
  • the invention of the method for purifying combustion exhaust gas according to claim 1 is directed to applying a combustion exhaust gas to which alcohol as a reducing agent is added to a denitration catalyst in which cobalt is supported on sodium-type zeolite at 180 to 300 ° C. It is characterized in that nitrogen oxides in the exhaust gas are removed by contact at the temperature.
  • the invention of claim 2 is the method for purifying combustion exhaust gas according to claim 1, wherein the denitration catalyst is a denitration catalyst in which cobalt and hydrogen are supported on sodium-type zeolite.
  • the invention according to claim 3 is the method for purifying combustion exhaust gas according to claim 1, wherein the denitration catalyst is a denitration catalyst in which cobalt and alkali metal or alkaline earth metal are supported on sodium-type zeolite. It is said.
  • the invention of claim 4 is the method for purifying combustion exhaust gas according to any one of claims 1 to 3, wherein the reducing agent is isopropyl alcohol, ethanol, or methanol.
  • the invention of claim 5 is the method for purifying combustion exhaust gas according to any one of claims 1 to 3, wherein the sodium type zeolite is a ZSM-5 (MFI) type zeolite or a mordenite (MOR) type. It is characterized by being a zeolite.
  • MFI ZSM-5
  • MOR mordenite
  • the invention of claim 6 is the method for purifying combustion exhaust gas according to claim 2 or 3, characterized in that the combustion exhaust gas is an exhaust gas obtained by burning C heavy oil.
  • the invention according to claim 7 is the method for purifying combustion exhaust gas according to claim 3, wherein the alkali metal is potassium (K), the alkaline earth metal is calcium (Ca), strontium (Sr), and It is characterized by being at least one metal selected from the group consisting of barium (Ba).
  • the invention of claim 8 is a denitration catalyst used in the method for purifying combustion exhaust gas according to claim 1, wherein cobalt is supported on sodium-type zeolite, and the combustion exhaust gas to which alcohol is added as a reducing agent. On the other hand, the contact is made at a temperature of 180 to 300 ° C.
  • the invention according to claim 9 is the denitration catalyst according to claim 8, wherein the denitration catalyst is a denitration catalyst in which cobalt and hydrogen are supported on sodium-type zeolite.
  • a tenth aspect of the invention is the denitration catalyst according to the eighth aspect, wherein the denitration catalyst is a denitration catalyst in which cobalt and an alkali metal or an alkaline earth metal are supported on a sodium-type zeolite.
  • the invention of claim 11 is the denitration catalyst according to any one of claims 8 to 10, wherein the sodium-type zeolite comprises ZSM-5 (MFI) zeolite or mordenite (MOR) zeolite. It is characterized by being.
  • MFI ZSM-5
  • MOR mordenite
  • the invention of claim 12 is the denitration catalyst according to claim 10, wherein the alkali metal is potassium (K), and the alkaline earth metal is calcium (Ca), strontium (Sr), and barium (Ba ) At least one metal selected from the group consisting of:
  • the exhaust gas temperature is as low as 300 ° C. or less, for example, marine engines, that is, marine vessels. This produces an effect that nitrogen oxides can be effectively and efficiently reduced from combustion exhaust gas discharged from large-scale diesel engines, large-scale boilers such as factories and power plants, and district heating and cooling.
  • NOx nitrogen oxides
  • SOx sulfur oxides
  • the method for purifying combustion exhaust gas according to the present invention comprises contacting a combustion exhaust gas to which alcohol is added as a reducing agent with a denitration catalyst in which cobalt is supported on sodium-type zeolite at a temperature of 180 to 300 ° C. It is characterized by removing oxides.
  • the denitration catalyst used in the combustion exhaust gas purification method of the present invention is a denitration catalyst in which cobalt and hydrogen are supported on sodium-type zeolite, or a denitration catalyst in which cobalt and alkali metal or alkaline earth metal are supported on sodium-type zeolite. May be.
  • the alcohol that is the reducing agent used in the present invention is not particularly limited, and isopropyl alcohol, ethanol, or methanol is generally preferable. The reason is that an alcohol with less carbon that is considered to be completely oxidized is preferable.
  • the hydrocarbon which is the reducing agent used in the example of Patent Document 3 described above, is effective only when the exhaust gas temperature is high.
  • hydrocarbons are designated as flammable gases, and when a flammable gas is loaded on a ship, it is necessary to install a safety device or the like. is there.
  • the denitration catalyst used in the method for purifying combustion exhaust gas of the present invention is a catalyst in which cobalt (Co) is supported on sodium-type zeolite having an acid strength corresponding to Hammett's acidity function H 0 of ⁇ 7 or less, or the sodium-type catalyst It is preferable that cobalt and hydrogen are supported on zeolite, or that cobalt and an alkali metal or alkaline earth metal are supported on the sodium-type zeolite.
  • Hammett's acidity function H 0 is defined by the ability of an acid point on the surface of a solid acid to give a proton to a base (Bronsted acidity) or the ability to receive an electron pair from a base (Lewis acidity), and is expressed by a pKa value. It can be measured by a known indicator method or gas base adsorption method. For example, by measuring the amount of heat when ammonia is adsorbed to the acid point, it can be measured using an ammonia adsorption heat method for measuring the acid strength distribution.
  • the acid strength H 0 of the Hammett of zeolite varies depending on the composition ratio of the zeolite, the preparation method of the zeolite, and the structure of the zeolite.
  • the acid strength H 0 of the Hammett of zeolite is determined by the structure of the zeolite such that mordenite (MOR) ⁇ ZSM-5 (MFI) ⁇ BEA ( ⁇ ) ⁇ Y.
  • the sodium-type zeolite is preferably composed of ZSM-5 (MFI) zeolite or mordenite (MOR) zeolite.
  • the catalyst in which Co is supported on the proton-type ⁇ zeolite described in Patent Document 3 described above has acid sites of H and Co on the catalyst surface.
  • a catalyst in which Co is supported on a sodium-type zeolite having an acid strength corresponding to Hammett acidity function H 0 of ⁇ 7 or less has acid sites of Na and Co on the catalyst surface.
  • the strength of the acid point is H>Co> Na, and it is considered that the stronger the acid point, the more easily the ethanol that is the reducing agent reacts. For this reason, in the proton type, a reaction between protons and ethanol unrelated to the denitration reaction occurs, and ethanol may be consumed excessively.
  • sodium-type zeolite excessive consumption of ethanol is suppressed, and the performance is improved.
  • the denitration catalyst according to the present invention is brought into contact with combustion exhaust gas to which alcohol is added as a reducing agent at a temperature of 180 to 300 ° C.
  • the catalyst of the present invention excellent nitrogen oxide removal performance can be obtained even when the temperature of the exhaust gas is relatively low, such as about 180 to 300 ° C.
  • the sulfur oxide (SOx) contained in the exhaust gas for ships becomes anhydrous sulfuric acid, which combines with moisture and becomes sulfuric acid (H 2 SO 4 ).
  • the temperature of the exhaust gas for ships is not set to 180 ° C. or lower, and the denitration catalyst according to the present invention is preferably 180 ° C. or higher with respect to the combustion exhaust gas to which alcohol is added as a reducing agent.
  • the manufacturing method of the denitration catalyst used in the method for purifying combustion exhaust gas of the present invention is as follows.
  • the denitration catalyst when the denitration catalyst is obtained by loading cobalt (Co) on sodium-type zeolite having acid strength corresponding to Hammett acidity function H 0 of ⁇ 7 or less, ZSM-5 (MFI) -type zeolite Or a mordenite (MOR) type zeolite is used, for example, cobalt nitrate [Co (NO 3 ) 2 ], cobalt acetate [Co (C 2 H 3 O 2 ) 2 ], cobalt chloride [CoCl 2 ], cobalt formate [CoC 4 H 14. In an aqueous solution of a cobalt compound such as O 8 )], stirred at a temperature of 70 to 90 ° C.
  • a cobalt compound such as O 8
  • the denitration catalyst of the present invention made of cobalt (Co) ion-exchanged zeolite is produced by calcining at a temperature of 450 to 550 ° C. for 3 to 5 hours.
  • the amount of Co supported by the denitration catalyst according to the present invention is preferably 2 to 4% by weight.
  • the amount of cobalt ions supported on the sodium-type zeolite is less than 2% by weight, the amount supported is small, that is, the number of active sites is too small.
  • the amount of cobalt ions supported exceeds 4% by weight, the proportion of Co oxide on the surface that does not contribute to the denitration reaction increases, which is not preferable.
  • the denitration catalyst when the denitration catalyst is obtained by loading cobalt and hydrogen on sodium-type zeolite having an acid strength corresponding to Hammett acidity function H 0 of ⁇ 7 or less, ZSM-5 (MFI) zeolite or mordenite (The MOR) zeolite is placed in an aqueous solution of ammonium nitrate (NH 4 NO 3 ), stirred at a temperature of 70-90 ° C. for 2-24 hours, then filtered and washed. The filtered washing is then dried at a temperature of 100 to 120 ° C. for 1 to 4 hours to obtain NH 4 -MFI zeolite or NH 4 -MOR zeolite.
  • NH 4 NO 3 ammonium nitrate
  • NH 4 -MFI zeolite or NH 4 -MOR zeolite is converted into, for example, cobalt nitrate [Co (NO 3 ) 2 ], cobalt acetate [Co (C 2 H 3 O 2 ) 2 ], cobalt chloride [CoCl 2 ], formic acid. It is placed in an aqueous solution of a cobalt compound such as cobalt [CoC 4 H 14 O 8 ), stirred at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then filtered and washed. Subsequently, the filtered and washed product is dried at a temperature of 100 to 120 ° C.
  • a cobalt compound such as cobalt [CoC 4 H 14 O 8
  • the Co loading is preferably 1 to 4% by weight.
  • the loading amount of cobalt ions is less than 1% by weight, the loading amount is small, that is, the number of active sites is too small.
  • the amount of cobalt ions supported exceeds 4% by weight, the proportion of Co oxide on the surface that does not contribute to the denitration reaction increases, which is not preferable.
  • the denitration catalyst is a sodium type zeolite in which cobalt and alkali metal or alkaline earth metal are supported
  • ZSM-5 (MFI) zeolite or mordenite (MOR) zeolite is replaced with alkali metal or alkaline earth. It is put into an aqueous solution of a metal, stirred at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then filtered and washed. The filtered and washed product was then dried at a temperature of 100 to 120 ° C. for 1 to 4 hours to obtain an alkali metal or alkaline earth metal ion exchange zeolite.
  • the alkali metal includes potassium (K), and the alkaline earth metal is at least one selected from the group consisting of calcium (Ca), strontium (Sr), and barium (Ba). These metals are mentioned.
  • an aqueous solution of nitric acid, aqueous solution of acetic acid, aqueous solution of chloride, aqueous solution of formic acid or the like of an alkali metal or alkaline earth metal can be used.
  • an alkali metal or alkaline earth metal ion-exchanged zeolite is converted into, for example, cobalt nitrate [Co (NO 3 ) 2 ], cobalt acetate [Co (C 2 H 3 O 2 ) 2 ], cobalt chloride [CoCl 2 ], cobalt formate. It is put in an aqueous solution of a cobalt compound such as [CoC 4 H 14 O 8 )], stirred at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then washed by filtration. The filtered and washed product is then dried at a temperature of 100 to 120 ° C.
  • a cobalt compound such as [CoC 4 H 14 O 8 )
  • the denitration catalyst of the present invention is produced.
  • the supported amount of alkali metal or alkaline earth metal is preferably 1 to 4% by weight.
  • the supported amount of ions of alkali metal or alkaline earth metal is less than 1% by weight, it is not preferable because the supported amount is small, that is, there are too few active points.
  • the supported amount of alkali metal or alkaline earth metal ions exceeds 4% by weight, the ratio of surface alkali metal or alkaline earth metal oxides that do not contribute to the denitration reaction increases, which is not preferable.
  • the Co loading is preferably 1 to 4% by weight.
  • the amount of cobalt ions supported is less than 1% by weight, the amount supported is small, that is, the number of active sites is too small, which is not preferable.
  • the amount of cobalt ions supported exceeds 4% by weight, the proportion of Co oxide on the surface that does not contribute to the denitration reaction increases, which is not preferable.
  • the denitration catalyst used in the method for purifying combustion exhaust gas of the present invention can be manufactured as a honeycomb type denitration catalyst by, for example, supporting sodium-type zeolite and cobalt on a honeycomb structure.
  • a base material for manufacturing a honeycomb structure is manufactured by applying a slurry made of sodium-type zeolite, water, and silica sol to glass paper.
  • the step of obtaining a corrugated plate-like substrate by processing the sodium-type zeolite-supporting substrate into a corrugated shape the step of obtaining the flat plate-like substrate by processing the above-mentioned substrate into a flat plate, and the corrugated shape
  • a honeycomb structure is manufactured by carrying out a step of alternately laminating the substrate and the flat substrate.
  • the denitration catalyst when the denitration catalyst is obtained by loading cobalt (Co) on sodium-type zeolite having an acid strength corresponding to Hammett acidity function H 0 of ⁇ 7 or less, it is further prepared by the above method.
  • the honeycomb type denitration catalyst is manufactured by carrying out a step of ion exchange of cobalt on the sodium type zeolite supporting honeycomb structure.
  • the above-mentioned sodium-type zeolite-supporting base material is processed into a corrugated shape to obtain a corrugated plate-like base material
  • the above-mentioned base material is processed into a flat plate to obtain a flat base-like base material
  • a step of obtaining a corrugated catalyst by ion-exchanging cobalt to a base material a step of obtaining a flat catalyst by ion-exchanging cobalt to the flat base material; and the corrugated catalyst and the flat catalyst.
  • a honeycomb type denitration catalyst is manufactured by alternately stacking layers.
  • the denitration catalyst when the denitration catalyst is obtained by loading cobalt and hydrogen on a sodium-type zeolite having an acid strength corresponding to Hammett acidity function H 0 of ⁇ 7 or less, sodium produced by the above method is further used.
  • a honeycomb-type denitration catalyst is manufactured by performing an ion exchange process of cobalt and hydrogen on the honeycomb structure supporting a zeolite.
  • the above-mentioned sodium-type zeolite-supporting base material is processed into a corrugated shape to obtain a corrugated plate-like base material
  • the above-mentioned base material is processed into a flat plate to obtain a flat base-like base material
  • the corrugated catalyst A step of alternately laminating the flat catalyst is carried out to produce a honeycomb type denitration catalyst.
  • the denitration catalyst when the denitration catalyst is obtained by supporting cobalt and an alkali metal or alkaline earth metal on sodium-type zeolite, the catalyst is further added to the sodium-type zeolite-supported honeycomb structure manufactured by the above method. And a step of ion exchange of alkali metal or alkaline earth metal is performed to produce a honeycomb-type denitration catalyst.
  • the above-mentioned sodium-type zeolite-supporting base material is processed into a corrugated shape to obtain a corrugated plate-like base material
  • the above-mentioned base material is processed into a flat plate to obtain a flat base-like base material
  • a step of obtaining a catalyst and a step of alternately laminating the corrugated catalyst and the flat plate catalyst are carried out to produce a honeycomb type denitration catalyst.
  • a sodium-type zeolite is fixed to glass paper using an inorganic binder such as silica sol, and a desired shape such as a honeycomb structure can be obtained by molding this.
  • the high concentration slurry can be used, and the operation of supporting the sodium-type zeolite is only required once. Also, unlike the method of generating sodium-type zeolite on the substrate, it does not require the high-temperature and high-pressure conditions required for sodium-type zeolite generation because it supports already prepared sodium-type zeolite. If there is, it can be sufficiently produced.
  • the solid support is advantageous because it is a molded support.
  • the sodium-type zeolite is preferably made of ZSM-5 (MFI) zeolite or mordenite (MOR) zeolite.
  • silica sol an acidic type containing about 20% by weight of silica can be used.
  • the weight ratio of the sodium-type zeolite, water, and silica sol is adjusted to, for example, 100: 100: 46.
  • Silica sol contained in such a slurry functions as an inorganic binder, and when corrugated, it can retain the corrugated shape and is intended to produce a honeycomb structure that can be corrugated.
  • the base material can be obtained.
  • any conventionally known method may be used.
  • a flat substrate on which sodium-type zeolite is supported is obtained. Since the slurry is applied to the flat glass paper in this way, there is no possibility of clogging when the slurry concentration is high, and a high concentration slurry can be used for the application from the beginning, and a single carrying operation.
  • a sodium-type zeolite-supporting substrate can be obtained. (Base material molding)
  • the sodium-type zeolite supporting substrate as described above can be formed into a corrugated shape using a corrugator.
  • an inorganic binder such as silica sol added by applying slurry serves as a binder for glass paper. As a result, the corrugation can be maintained after the glass paper is molded. Therefore, the sodium-type zeolite-supporting base material is a material suitable for producing a honeycomb structure.
  • the base material is corrugated.
  • the base material is corrugated.
  • To form a corrugated base material and alternately stack a plurality of corrugated base materials and a plurality of flat base materials having a flat surface shape that has not been subjected to molding processing.
  • the sodium-type zeolite-supporting substrate may be used for corrugating the sodium-type zeolite-supporting substrate.
  • the sodium-type zeolite is supported on a gear-shaped disk having a corrugated outer periphery. By rotating the substrate, it is possible to obtain a corrugated plate along the outer peripheral waveform of the disk.
  • a metal panel having a groove having a predetermined shape is used, and the sodium-type zeolite-supporting substrate placed in the mold is pressed along the groove of the mold by a pressing jig. It is also possible to mold.
  • the conditions at that time are not particularly limited, but, for example, they are placed in an air atmosphere at a temperature of 110 to 300 ° C. for a period of 1 to 3 hours.
  • the flat substrate and corrugated substrate obtained as described above are subjected to a firing step.
  • the conditions at that time are not particularly limited.
  • the film is placed in an air atmosphere at a temperature of 500 to 550 ° C. for 3 hours.
  • the disk that rotates and moves the flat plate base material after drying has a flat plate-like substrate and a corrugated plate-like substrate that are alternately arranged when the honeycomb structure is manufactured. It is convenient to place it side by side with the disk.
  • a honeycomb structure can be obtained by alternately laminating the corrugated substrate and the flat substrate processed as described above.
  • each flat plate-like substrate and corrugated plate-like substrate need only be kept in contact with each other. It is also possible to maintain the contact state by placing it in the box.
  • a honeycomb denitration catalyst can be obtained by supporting cobalt having catalytic activity on the honeycomb structure obtained as described above.
  • cobalt is supported on a sodium-type zeolite having an acid strength corresponding to Hammett acidity function H 0 of ⁇ 7 or less.
  • a honeycomb structure supporting the above ZSM-5 (MFI) -type zeolite or mordenite (MOR) -type zeolite is, for example, cobalt nitrate [ Put in an aqueous solution of a cobalt compound such as Co (NO 3 ) 2 ], cobalt acetate [Co (C 2 H 3 O 2 ) 2 ], cobalt chloride [CoCl 2 ], cobalt formate [CoC 4 H 14 O 8 )].
  • a cobalt compound such as Co (NO 3 ) 2
  • Co (C 2 H 3 O 2 ) 2 cobalt acetate
  • CoCl 2 cobalt chloride
  • CoC 4 H 14 O 8 cobalt formate
  • a honeycomb structure carrying cobalt (Co) ion-exchanged zeolite and carrying the denitration catalyst of the present invention, that is, a honeycomb type denitration catalyst is obtained. It is.
  • the amount of Co supported by the denitration catalyst according to the present invention is preferably 2 to 4% by weight.
  • a step of applying a slurry made of sodium-type zeolite, water, and silica sol to glass paper is carried out to produce a substrate for producing a honeycomb structure, Processing the sodium-type zeolite-supporting base material into a corrugated shape to obtain a corrugated base material, processing the base material into a flat plate to obtain a flat base material, and the corrugated base material.
  • a honeycomb type denitration catalyst can be obtained by supporting cobalt and hydrogen on a sodium type zeolite having an acid strength corresponding to Hammett acidity function H 0 of ⁇ 7 or less.
  • a honeycomb structure supporting the above ZSM-5 (MFI) type zeolite or mordenite (MOR) type zeolite was converted to ammonium nitrate (NH 4 It is placed in an aqueous solution of NO 3 ), immersed at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then washed. Subsequently, the washed product is dried at a temperature of 100 to 120 ° C. for 1 to 4 hours to obtain NH 4 -MFI zeolite or NH 4 -MOR zeolite.
  • NH 4 -MFI zeolite or NH 4 -MOR zeolite is converted into, for example, cobalt nitrate [Co (NO 3 ) 2 ], cobalt acetate [Co (C 2 H 3 O 2 ) 2 ], cobalt chloride [CoCl 2 ], formic acid. It is placed in an aqueous solution of a cobalt compound such as cobalt [CoC 4 H 14 O 8 ), immersed at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then washed. Next, the washed product is dried at a temperature of 100 to 120 ° C. for 1 to 4 hours, and further calcined at a temperature of 450 to 550 ° C.
  • the amount of Co supported by the denitration catalyst according to the present invention is preferably 1 to 4% by weight.
  • a step of applying a slurry made of sodium-type zeolite, water, and silica sol to glass paper is carried out to produce a substrate for producing a honeycomb structure, Processing the sodium-type zeolite-supporting base material into a corrugated shape to obtain a corrugated base material, processing the base material into a flat plate to obtain a flat base material, and the corrugated base material.
  • a honeycomb type denitration catalyst may be manufactured by alternately stacking layers.
  • a honeycomb-type denitration catalyst can be obtained by supporting cobalt and an alkali metal or an alkaline earth metal on a sodium-type zeolite having an acid strength corresponding to a Hammett acidity function H 0 of ⁇ 7 or less. it can.
  • a honeycomb structure supporting the above ZSM-5 (MFI) type zeolite or mordenite (MOR) type zeolite when performing ion exchange for supporting cobalt and alkali metal or alkaline earth metal on zeolite as described above Is placed in an aqueous solution of an alkali metal or an alkaline earth metal, immersed at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then washed. The washed product was then dried at a temperature of 100 to 120 ° C. for 1 to 4 hours to obtain an alkali metal or alkaline earth metal ion exchange zeolite.
  • MFI ZSM-5
  • MOR mordenite
  • the alkali metal includes potassium (K), and the alkaline earth metal is at least one selected from the group consisting of calcium (Ca), strontium (Sr), and barium (Ba). These metals are mentioned.
  • an aqueous solution of nitric acid, aqueous solution of acetic acid, aqueous solution of chloride, aqueous solution of formic acid or the like of an alkali metal or alkaline earth metal can be used.
  • an alkali metal or alkaline earth metal ion-exchanged zeolite is converted into, for example, cobalt nitrate [Co (NO 3 ) 2 ], cobalt acetate [Co (C 2 H 3 O 2 ) 2 ], cobalt chloride [CoCl 2 ], cobalt formate. It is placed in an aqueous solution of a cobalt compound such as [CoC 4 H 14 O 8 )], immersed at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then washed. Next, the washed product is dried at a temperature of 100 to 120 ° C. for 1 to 4 hours, and further calcined at a temperature of 450 to 550 ° C.
  • a honeycomb structure which is produced and carries the denitration catalyst of the present invention, that is, a honeycomb type denitration catalyst is obtained.
  • the supported amount of alkali metal or alkaline earth metal is preferably 1 to 4% by weight.
  • a step of applying a slurry made of sodium-type zeolite, water, and silica sol to glass paper is carried out to produce a substrate for producing a honeycomb structure, Processing the sodium-type zeolite-supporting base material into a corrugated shape to obtain a corrugated base material, processing the base material into a flat plate to obtain a flat base material, and the corrugated base material.
  • a step of alternately laminating the corrugated catalyst and the flat catalyst may be carried out to produce a honeycomb type denitration catalyst.
  • the method for purifying combustion exhaust gas of the present invention high concentrations of nitrogen oxides (NOx) and sulfur oxides (SOx) are present, and the exhaust gas temperature is as low as 300 ° C. or less, for example, marine engines, ie large marine vessels.
  • Nitrogen oxides can be effectively reduced from combustion exhaust gas discharged from diesel engines, factories, power plants, large-scale boilers such as district heating and cooling.
  • Example 1 As a denitration catalyst used in the method for purifying combustion exhaust gas of the present invention, cobalt (Co) is added to ZSM-5 (MFI) type zeolite, which is a sodium type zeolite having an acid strength corresponding to Hammett's acidity function H 0 of ⁇ 7. A supported catalyst was produced.
  • Co cobalt
  • MFI ZSM-5
  • FIG. 1 shows a flow chart of a denitration catalyst performance evaluation test apparatus.
  • the catalyst comprising the Co / ZSM-5 (MFI) type zeolite obtained as described above was pulverized after press molding, and sized to a mesh size of 28 to 14, and the test apparatus shown in the flow chart of FIG.
  • a denitration reactor comprising a stainless steel reaction tube having an inner diameter of 10.6 mm is filled with catalyst particles, isopropyl alcohol (IPA) is used as a reducing agent at a concentration of 200 ppm, and exhaust gas having a NO concentration of 200 ppm is used.
  • IPA isopropyl alcohol
  • the gas analysis of the reactor exit measured the exit NOx density
  • Denitration rate (%) (NOx in ⁇ NOx out ) / NOx in ⁇ 100 (1)
  • the results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 2 below.
  • Examples 2 to 5 As in the case of Example 1, the denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method of the present invention is performed under the test conditions shown in Table 1 above, but differs from the case of Example 1 above.
  • the exhaust gas having a NO concentration of 1000 ppm was the same as the exhaust gas having a NO concentration of 200 ppm in Example 3, except that isopropyl alcohol (IPA) was used as the reducing agent at a concentration of 700 ppm.
  • IPA isopropyl alcohol
  • Example 4 ethanol was used at a concentration of 200 ppm.
  • Example 4 the NO concentration was 1000 ppm for the exhaust gas.
  • ethanol was used at a concentration of 700 ppm.
  • Example 5 the NO concentration was 1000 ppm for the exhaust gas.
  • methanol is used at a concentration of 4000 ppm.
  • Table 2 The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 2 below. (Examples 6 to 7) As in the case of Example 1, the denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method of the present invention is performed under the test conditions shown in Table 1 above, but differs from the case of Example 1 above.
  • MOR mordenite
  • Example 6 using the obtained denitration catalyst made of Co / mordenite (MOR) type zeolite according to the present invention, NOx concentration was 200 ppm, and ethanol was used as a reducing agent at a concentration of 200 ppm.
  • No. 7 a denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method of the present invention was carried out using the same denitration catalyst and using ethanol as a reducing agent at a concentration of 700 ppm for exhaust gas having a NO concentration of 1000 ppm. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 2 below.
  • Example 1 For comparison, a denitration catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas is performed in the same manner as in the case of the above Example 1.
  • the difference from the case of Example 1 is that This is in that a catalyst in which cobalt (Co) is supported on BEA type zeolite, which is a sodium type zeolite having an acid strength corresponding to Hammett's acidity function H 0 of 5, is used, and ethanol is used as a reducing agent.
  • BEA type zeolite which is a sodium type zeolite having an acid strength corresponding to Hammett's acidity function H 0 of 5
  • ethanol is used as a reducing agent.
  • Example 3 For comparison, a denitration catalyst performance evaluation test corresponding to a method for purifying combustion exhaust gas is performed in the same manner as in the case of Example 1. The difference from the case of Example 1 is that the method for purifying combustion exhaust gas
  • a denitration catalyst used in the present invention a catalyst in which cobalt (Co) is supported on a Y-type zeolite, which is a sodium-type zeolite having an acid strength corresponding to a Hammett acidity function H 0 of ⁇ 3, and a reducing agent are used. The point is that ethanol was used.
  • a commercially available Y-type zeolite (trade name: Mizuka Sieves Y-420, manufactured by Mizusawa Chemical Industry Co., Ltd .: acid strength-3) was placed in 200 ml of a 0.1 M Co (NO 3 ) 2 aqueous solution at a temperature of 80 ° C.
  • the mixture was stirred for 24 hours, filtered and washed, then dried at a temperature of 110 ° C. for 3 hours, and further calcined at a temperature of 500 ° C. for 4 hours to obtain a cobalt (Co) ion-exchanged zeolite.
  • the amount of Co supported by this catalyst was 10.33% by weight, and the exchange rate of cobalt ions with respect to the Y-type zeolite was 22%.
  • the denitration tests of Examples 1 to 7 according to the present invention all showed a higher denitration rate than the denitration tests of Comparative Examples 1 to 4, and according to the present invention. It can be seen that the denitration catalyst has high catalytic performance at a reaction temperature of 250 ° C.
  • a reaction rate constant K when the denitration reaction is assumed to be a primary reaction of NOx was used as an index. That is, K is represented by the following formula. Then, in the denitration tests of Examples 1 to 7 and the denitration tests of Comparative Examples 1 to 4 according to the present invention, the reaction rate constant K was calculated from the following formula, and the obtained reaction rate constant K was The results are shown in Table 3 below.
  • ZSM-5 (MFI) type zeolite (trade name: Mizuka Sieves EX122, manufactured by Mizusawa Chemical Industry Co., Ltd .: acid strength -7), which is a commercially available sodium type zeolite, was added to 0.1 mol (M) of cobalt nitrate [Co (NO 3 ) 2 ]
  • M cobalt nitrate
  • Co (Co) ion exchange zeolite was obtained.
  • the amount of Co supported by this catalyst was 2.6% by weight, and the exchange rate of cobalt ions with respect to the ZSM-5 (MFI) type zeolite was 32%.
  • Example 8 of the present invention this Co / ZSM-5 (MFI) type zeolite was exposed to a gas containing sulfur trioxide (SO 3 ) for 20 hours under the conditions shown in Table 4 below.
  • SO 3 was sent to the evaporation pipe using a fixed liquid feed pump, gasified in the evaporator, and then flowed into the reaction pipe.
  • Example 9 of the present invention the Co / ZSM-5 (MFI) type zeolite was exposed to a gas containing sulfur trioxide (SO 3 ) for 36 hours under the conditions shown in Table 4 below.
  • SO 3 sulfur trioxide
  • a denitration catalyst performance evaluation test was conducted in the same manner as in Example 8, and the results of the obtained denitration catalyst performance evaluation test are shown in Table 5 below.
  • Example 5 the denitration catalyst performance of Example 4 using a denitration catalyst made of Co / ZSM-5 (MFI) type zeolite not exposed to a gas containing sulfur trioxide (SO 3 ) is shown as a reference. The results of the evaluation test were also shown.
  • MFI Co / ZSM-5
  • SO 3 sulfur trioxide
  • the denitration catalyst according to the present invention has excellent resistance to sulfur oxide (SOx) contained in a large amount of exhaust gas discharged from marine engines.
  • SOx sulfur oxide
  • Example 10 As a denitration catalyst used in the method for purifying combustion exhaust gas of the present invention, ZSM-5 (MFI) type zeolite, which is a sodium type zeolite having acid strength corresponding to Hammett's acidity function H 0 of ⁇ 7, cobalt (Co) and A catalyst carrying hydrogen (H) was produced.
  • MFI MFI type zeolite
  • NH 4 -MFI zeolite was put into 200 ml of 0.1 mol (M) cobalt nitrate [Co (NO 3 ) 2 ] aqueous solution, stirred at a temperature of 80 ° C. for 24 hours, and then washed by filtration. Next, the filtered and washed product is dried at 110 ° C. for 3 hours, and further calcined at 500 ° C. for 4 hours, whereby the hydrogen (H) / cobalt (Co) ion exchange ZSM-5 (MFI) zeolite of the present invention is obtained.
  • the amount of Co supported by this catalyst was 1.46% by weight.
  • the catalyst made of H / Co-ZSM-5 (MFI) type zeolite obtained as described above is pulverized after press molding and sized to a mesh size of 28 to 14, and the denitration catalyst powder is obtained.
  • the test apparatus shown in the flow chart of FIG. 1 a denitration reactor composed of a stainless steel reaction tube having an inner diameter of 10.6 mm is filled with denitration catalyst powder, and ethanol as a reducing agent is added at a concentration of 700 ppm.
  • a performance evaluation test was performed under the test conditions shown in Table 1 above. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 6 below.
  • Example 11 As in the case of Example 10, the NOx removal catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas of the present invention is performed under the test conditions shown in Table 1, but is different from the case of Example 10 above. Is that methanol is used as a reducing agent at a concentration of 4000 ppm. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 6 below. Table 6 below also shows the results of the denitration catalyst performance evaluation test of Comparative Examples 2 and 4 described above for comparison.
  • the denitration tests of Examples 10 and 11 according to the present invention all showed a higher denitration rate than the denitration tests of Comparative Examples 2 and 4, and according to the present invention. It can be seen that the denitration catalyst has high catalytic performance at a reaction temperature of 250 ° C.
  • Example 12 the H / Co-ZSM-5 (MFI) type zeolite produced in Example 10 according to the present invention was converted to a gas containing sulfur trioxide (SO 3 ) before performing the denitration catalyst performance evaluation test. It was exposed for 47 hours.
  • sulfur trioxide (SO 3 ) was sent to the evaporation pipe using a fixed liquid feed pump, gasified in the evaporator, and then flowed into the reaction pipe.
  • Example 13 In the same manner as in Example 10, the denitration catalyst according to the present invention was tested for resistance to sulfur trioxide (SO 3 ). The difference from Example 10 is that in Example 11, the present invention The H / Co-ZSM-5 (MFI) type zeolite produced in Example 10 according to the present invention was exposed to a gas containing sulfur trioxide (SO 3 ) for 110 hours before performing the denitration catalyst performance evaluation test. .
  • MFI Co-ZSM-5
  • the dried product was put into 200 ml of 0.1 mol (M) cobalt nitrate [Co (NO 3 ) 2 ] aqueous solution, stirred at a temperature of 80 ° C. for 24 hours, filtered and washed.
  • the filtered and washed product is then dried at 110 ° C. for 3 hours and further calcined at 500 ° C. for 4 hours, whereby the cobalt (Co) / barium (Ba) ion-exchanged ZSM-5 (MFI) zeolite of the present invention.
  • the amount of cobalt (Co) supported on this catalyst was 1.06% by weight, and the amount of barium (Ba) supported was 1.12% by weight.
  • the catalyst made of Co / Ba-ZSM-5 (MFI) zeolite obtained as described above is pulverized after press molding and sized to a mesh size of 28 to 14 to prepare a denitration catalyst powder. did.
  • a denitration reactor composed of a stainless steel reaction tube having an inner diameter of 10.6 mm is filled with denitration catalyst powder, and ethanol is used as a reducing agent at a concentration of 200 ppm.
  • a performance evaluation test was conducted on the exhaust gas having a NO concentration of 200 ppm under the test conditions shown in Table 1 above. The results of the evaluation test of the obtained denitration catalyst performance are shown in Table 9 below.
  • Example 15 In the same manner as in Example 14, the denitration catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas of the present invention is performed under the test conditions shown in Table 1 above, but differs from the case of Example 14 above.
  • Example 15 ethanol is used as a reducing agent at a concentration of 700 ppm for exhaust gas having a NO concentration of 1000 ppm.
  • the results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 9 below.
  • Example 16 In the same manner as in Example 14, the denitration catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas of the present invention is performed under the test conditions shown in Table 1 above, but differs from the case of Example 14 above.
  • Example 16 In the same manner as in Example 14, the denitration catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas of the present invention is performed under the test conditions shown in Table 1 above, but differs from the case of Example 14 above.
  • a denitration catalyst of the present invention cobalt (Co) and potassium (K) are supported on ZSM-5 (MFI) zeolite, which is a sodium-type zeolite having an acid strength corresponding to Hammett's acidity function H 0 of ⁇ 7. This is in the point of using a new catalyst.
  • MFI ZSM-5
  • This denitration catalyst was produced as follows. First, 10 g of a commercially available ZSM-5 (MFI) zeolite (trade name: Mizuka Sieves EX122, manufactured by Mizusawa Chemical Industry Co., Ltd .: acid strength -7) was added to a 0.1 mol (M) potassium nitrate [K (NO 3 ) 2 ] aqueous solution. The solution was placed in 200 ml, stirred at a temperature of 80 ° C. for 24 hours, filtered and washed. Subsequently, the filtered washing product was dried at a temperature of 110 ° C. for 3 hours.
  • MFI ZSM-5
  • MFI 0.1 mol
  • K (NO 3 ) 2 potassium nitrate
  • the dried product was put into 200 ml of 0.1 mol (M) cobalt nitrate [Co (NO 3 ) 2 ] aqueous solution, stirred at a temperature of 80 ° C. for 24 hours, filtered and washed. The filtered and washed product was then dried at 110 ° C. for 3 hours and further calcined at 500 ° C. for 4 hours to obtain a cobalt (Co) / potassium (K) ion exchange ZSM-5 (MFI) zeolite. .
  • This catalyst had a cobalt (Co) loading of 2.24% by weight and a potassium (K) loading of 1.3% by weight.
  • Example 18 Using the denitration catalyst according to the present invention thus produced, a denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method of the present invention was carried out in the same manner as in Example 14. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 9 below. (Example 18) In the same manner as in Example 14, the denitration catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas of the present invention is performed under the test conditions shown in Table 1 above, but differs from the case of Example 14 above.
  • cobalt (Co) and strontium (Sr) are supported on ZSM-5 (MFI) zeolite, which is a sodium type zeolite having an acid strength corresponding to Hammett acidity function H 0 of ⁇ 7. This is in the point of using a new catalyst.
  • MFI ZSM-5
  • This denitration catalyst was produced as follows. First, 10 g of commercially available ZSM-5 (MFI) zeolite (trade name: Mizuka Sieves EX122, manufactured by Mizusawa Chemical Industry Co., Ltd .: acid strength -7) was added to 0.1 mol (M) of strontium nitrate [Sr (NO 3 ) 2 ]. The solution was placed in 200 ml of an aqueous solution, stirred at a temperature of 80 ° C. for 24 hours, and then washed by filtration. Subsequently, the filtered washing product was dried at a temperature of 110 ° C. for 3 hours.
  • MFI ZSM-5
  • MFI zeolite
  • Sr (NO 3 ) 2 strontium nitrate
  • the dried product was put into 200 ml of 0.1 mol (M) cobalt nitrate [Co (NO 3 ) 2 ] aqueous solution, stirred at a temperature of 80 ° C. for 24 hours, filtered and washed. The filtered and washed product was then dried at 110 ° C. for 3 hours and further calcined at 500 ° C. for 4 hours to obtain a cobalt (Co) / strontium (Sr) ion exchange ZSM-5 (MFI) zeolite. .
  • This catalyst had a cobalt (Co) loading of 1.20% by weight and a strontium (Sr) loading of 2.70% by weight.
  • Example 18 Using the thus-produced denitration catalyst according to the present invention, a denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method of the present invention was carried out in the same manner as in Example 14.
  • Example 18 For exhaust gas having a NO concentration of 1000 ppm, ethanol as a reducing agent was used at a concentration of 700 ppm.
  • Table 9 below shows the results of the denitration catalyst performance evaluation test of Comparative Examples 2 and 4 described above for comparison.
  • the denitration tests of Examples 14 to 18 according to the present invention all showed a higher denitration rate than the denitration tests of Comparative Examples 2 and 4, and according to the present invention. It can be seen that the denitration catalyst has high catalytic performance at a reaction temperature of 250 ° C.
  • Example 19 the Co / Ba-ZSM-5 (MFI) zeolite produced in Example 14 according to the present invention was added to a gas containing sulfur trioxide (SO 3 ) before performing a denitration catalyst performance evaluation test. Exposed time.
  • sulfur trioxide (SO 3 ) was sent to the evaporation pipe using a fixed liquid feed pump, gasified in the evaporator, and then flowed into the reaction pipe.
  • Example 11 The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 11 below.
  • Example 20 and 21 In the same manner as in Example 19, the denitration catalyst according to the present invention was tested for resistance to sulfur trioxide (SO 3 ).
  • Example 21 the Co / K-ZSM-5 (MFI) zeolite produced in Example 17 according to the present invention was subjected to a gas containing sulfur trioxide (SO 3 ) before the denitration catalyst performance evaluation test. Is exposed to 54 hours.
  • SO 3 sulfur trioxide
  • Nitrogen oxides can be effectively reduced from combustion exhaust gas discharged from large-scale boilers such as marine engines, ie large marine diesel engines, factories and power plants, district heating and cooling, etc. .

Abstract

[Problem] To provide: a method for cleaning a discharged combustion gas in which nitrogen oxides (NOx) and sulfur oxides (SOx) are present in high concentrations and which has a temperature as low as 300ºC or below, for example, a combustion gas discharged from an engine for ships, the method being effective in reducing the content of the nitrogen oxides in the discharged combustion gas; and a denitration catalyst. [Solution] The method for cleaning a discharged combustion gas comprises bringing the discharged combustion gas to which an alcohol has been added as a reducing agent, into contact at a temperature of 180-300ºC with a denitration catalyst that comprises a sodium-form zeolite and cobalt loaded thereinto, the zeolite having an acid strength which corresponds to a Hammett acidity function H0 of -7 or less, thereby removing the nitrogen oxides from the discharged gas. The reducing agent is preferably isopropyl alcohol, ethanol, or methanol. The sodium-form zeolite is preferably ZSM-5 (MFI)-type zeolite or mordenite (MOR)-type zeolite.

Description

燃焼排ガスの浄化方法、および脱硝触媒Combustion exhaust gas purification method and denitration catalyst
　本発明は、燃焼排ガスから窒素酸化物を除去する浄化方法、および脱硝触媒に関するものである。 The present invention relates to a purification method for removing nitrogen oxides from combustion exhaust gas, and a denitration catalyst.
　一般に、燃焼排ガス中に含まれている窒素酸化物（ＮＯｘ）を除去する方法は、排ガスに還元剤としてアンモニア（ＮＨ３）を添加したガスを、バナジウムやチタニアを主成分とする脱硝触媒に接触させることで除去するアンモニア選択接触還元（ＳＣＲ）法が主流であり、定置型の発電所の脱硝装置として実用化されている。 In general, the method of removing nitrogen oxides (NOx) contained in combustion exhaust gas is to contact a gas obtained by adding ammonia (NH 3 ) as a reducing agent to exhaust gas and contacting a denitration catalyst mainly composed of vanadium or titania. The ammonia selective catalytic reduction (SCR) method, which is removed by this process, is the mainstream, and has been put into practical use as a denitration device for stationary power plants.
　ところで、重油等の硫黄を含有する燃料を用いた場合、燃焼排ガス中には窒素酸化物（ＮＯｘ）と共に硫黄酸化物（ＳＯｘ）が存在する。硫黄酸化物が存在する場合の脱硝設備の運転温度は、触媒上への硫安の析出を防止する観点から、硫安の析出温度以上でなければならない。硫安の析出温度は排ガス中の三酸化硫黄（ＳＯ３）濃度およびアンモニア（ＮＨ３）濃度に関係があり、ＳＯ３濃度およびＮＨ３濃度が高くなると、硫安の析出温度が高くなる。 By the way, when fuel containing sulfur such as heavy oil is used, sulfur oxide (SOx) is present in the combustion exhaust gas together with nitrogen oxide (NOx). The operating temperature of the denitration facility when sulfur oxide is present must be equal to or higher than the precipitation temperature of ammonium sulfate from the viewpoint of preventing the precipitation of ammonium sulfate on the catalyst. The precipitation temperature of ammonium sulfate is related to the sulfur trioxide (SO 3 ) concentration and ammonia (NH 3 ) concentration in the exhaust gas. When the SO 3 concentration and the NH 3 concentration increase, the precipitation temperature of ammonium sulfate increases.
　定置型脱硝装置が設置されている石炭焚きボイラー排ガスにおいては、一般的にＳＯｘ濃度が１００ｐｐｍであるため、ＳＯ３濃度はその１０％の１０ｐｐｍ、ＮＯｘ濃度は５００ｐｐｍであるため、還元剤として使用するＮＨ３濃度は最大４００ｐｐｍである。この条件における硫安の析出温度は約２５０℃となる。通常、石炭焚きボイラー排ガス温度は３００～４００℃であり、硫安の析出温度である２５０℃より高いため、触媒への硫安の析出は起こらず、安定した触媒性能を維持することができる。 In coal-fired boiler exhaust gas in which stationary denitration equipment is installed, since the SOx concentration is generally 100 ppm, the SO 3 concentration is 10% of that 10 ppm, and the NOx concentration is 500 ppm, so it is used as a reducing agent. The NH 3 concentration is a maximum of 400 ppm. The precipitation temperature of ammonium sulfate under this condition is about 250 ° C. Normally, the coal-fired boiler exhaust gas temperature is 300 to 400 ° C., which is higher than the ammonium sulfate precipitation temperature of 250 ° C., so that ammonium sulfate does not precipitate on the catalyst and stable catalyst performance can be maintained.
　これに対し、船舶用機関から排出される排ガスは、燃料がＣ重油であるため、排ガス中のＳＯｘ濃度は６００ｐｐｍであり、ＮＯｘ濃度は１０００ｐｐｍである。また、還元剤として使用するＮＨ３濃度は最大８００ｐｐｍである。従って、この時の硫安の析出温度は約２８０℃となる。一方、船舶用排ガス温度は３００℃以下、通常２５０℃程度であるため、この条件では硫安が析出し、安定した触媒性能を維持することができない。 On the other hand, since the exhaust gas discharged from the marine engine is C heavy oil, the SOx concentration in the exhaust gas is 600 ppm and the NOx concentration is 1000 ppm. The NH 3 concentration used as the reducing agent is a maximum of 800 ppm. Accordingly, the precipitation temperature of ammonium sulfate at this time is about 280 ° C. On the other hand, the exhaust gas temperature for ships is 300 ° C. or lower, usually about 250 ° C., so that ammonium sulfate is precipitated under these conditions, and stable catalyst performance cannot be maintained.
　このように、高濃度のＳＯｘおよびＮＯｘが存在し、排ガス温度が低い船舶用機関から排出される排ガスの浄化処理で、アンモニアＳＣＲ法による脱硝触媒を使用するには、硫安の析出温度を排ガス温度以下にする必要がある。硫安の析出温度は、ＳＯ３濃度とＮＨ３濃度で決定される。ＮＨ３濃度は排ガス中のＮＯｘ濃度と目標脱硝率で決まるため、この値を低減することできない。従って、排ガス温度が硫安の析出温度より低い船舶用機関では、還元剤として使用するアンモニア（ＮＨ３）を吹き込む前に排熱を利用して、排ガス温度を再加熱して硫安の析出温度以上にすることで、アンモニアＳＣＲ法による脱硝触媒の使用を行っている。 Thus, in order to use a denitration catalyst by the ammonia SCR method in the purification treatment of exhaust gas discharged from a marine engine having a high concentration of SOx and NOx and having a low exhaust gas temperature, the precipitation temperature of ammonium sulfate is set to the exhaust gas temperature. Must be: The precipitation temperature of ammonium sulfate is determined by the SO 3 concentration and the NH 3 concentration. Since the NH 3 concentration is determined by the NOx concentration in the exhaust gas and the target denitration rate, this value cannot be reduced. Therefore, in a marine engine whose exhaust gas temperature is lower than the precipitation temperature of ammonium sulfate, exhaust gas is reheated before blowing ammonia (NH 3 ) used as a reducing agent, and the exhaust gas temperature is reheated to exceed the precipitation temperature of ammonium sulfate. By doing so, the denitration catalyst by the ammonia SCR method is used.
　その他、アンモニアＳＣＲ法以外の脱硝触媒としては、窒素酸化物を触媒と接触させるだけで窒素と酸素に分解する直接分解法がある。 Other than the ammonia SCR method, there is a direct decomposition method in which nitrogen oxide is decomposed into nitrogen and oxygen simply by contacting the nitrogen oxide with the catalyst.
　下記の特許文献１には、内燃機関から排出される排ガス中に含まれる窒素酸化物、特にＮＯを直接分解することができ、さらに分解によって発生する酸素（Ｏ２）や、排ガス中に共存する酸素（Ｏ２）による触媒活性の低下が極めて小さい窒素酸化物浄化触媒として、立方晶のＣ型構造を有する希土類酸化物ないし希土類複合酸化物からなる窒素酸化物浄化触媒が開示されている。しかしながら、この特許文献１に記載の窒素酸化物浄化触媒を用いた直接分解法による排ガスの浄化方法では、排ガス浄化の反応温度が６００℃以上と、非常に高いという問題があった。 In Patent Document 1 below, nitrogen oxides, particularly NO, contained in exhaust gas discharged from an internal combustion engine can be directly decomposed, and oxygen (O 2 ) generated by the decomposition and coexist in the exhaust gas. As a nitrogen oxide purification catalyst with a very small reduction in catalytic activity due to oxygen (O 2 ), a nitrogen oxide purification catalyst comprising a rare earth oxide or a rare earth composite oxide having a cubic C-type structure is disclosed. However, the exhaust gas purification method by the direct decomposition method using the nitrogen oxide purification catalyst described in Patent Document 1 has a problem that the reaction temperature for exhaust gas purification is as high as 600 ° C. or higher.
　また、ゼオライトに遷移金属を担持した触媒などが、炭化水素類を還元剤として用いるＮＯｘの還元除去反応に有効であるとする報告がなされている。 Further, it has been reported that a catalyst in which a transition metal is supported on zeolite is effective for the reduction and removal reaction of NOx using hydrocarbons as a reducing agent.
　下記の特許文献２には、硫黄酸化物を含む排ガスにおいても窒素酸化物（ＮＯｘ）を除去する脱硝性能を有する触媒を用いた排ガス浄化方法が開示されており、脱硝触媒として鉄、コバルト、銀、モリブデンまたはタングステンを担持させたβゼオライトを用い、還元剤としてのエタノールおよび／またはイソプロピルアルコールの存在下に、酸素過剰の排ガスを接触させることにより、排ガス中の窒素酸化物ＮＯｘを還元除去する排ガス浄化方法が記載されている。 Patent Document 2 below discloses an exhaust gas purification method using a catalyst having a denitration performance that removes nitrogen oxide (NOx) even in exhaust gas containing sulfur oxide, and iron, cobalt, silver as a denitration catalyst. Exhaust gas that reduces and removes nitrogen oxides NOx in exhaust gas by contacting β-zeolite supporting molybdenum or tungsten with oxygen-exhaust exhaust gas in the presence of ethanol and / or isopropyl alcohol as a reducing agent A purification method is described.
　下記の特許文献３には、触媒としてプロトン型βゼオライトを用い、還元剤としてのエタノールおよび／またはイソプロピルアルコールの存在下に、酸素過剰の排ガスを接触させて、排ガス中の窒素酸化物ＮＯｘを還元除去する排ガス浄化方法が記載されている。 In Patent Document 3 below, proton-type β zeolite is used as a catalyst, and oxygen-excess exhaust gas is contacted in the presence of ethanol and / or isopropyl alcohol as a reducing agent to reduce nitrogen oxide NOx in the exhaust gas. An exhaust gas purification method to be removed is described.
　下記の特許文献４には、触媒担体としてＳｉＯ２／Ａｌ２Ｏ３比が２７以上１００以下のＮａ－ＺＳＭ－５ゼオライトまたはＨ－ＺＳＭ－５型ゼオライトを用いて、前記触媒担体をコバルト塩水溶液（コバルトの硝酸塩、酢酸塩、塩化物等）に浸し、その触媒担体のＮａ（またはＨ）部分とＣｏとを、イオン交換率４０～１００％でイオン交換して、コバルトを担持したＺＳＭ－５型ゼオライトを脱硝触媒として用い、還元剤には、プロパン、ブタンを組成にもつ液化石油ガスを用いる排ガス浄化方法が記載されている。 In the following Patent Document 4, Na-ZSM-5 zeolite or H-ZSM-5 type zeolite having a SiO 2 / Al 2 O 3 ratio of 27 or more and 100 or less is used as a catalyst carrier, and the catalyst carrier is a cobalt salt aqueous solution. ZSM-5 carrying cobalt by ion-exchanging the Na (or H) portion of the catalyst support and Co at an ion exchange rate of 40 to 100% by immersing in (cobalt nitrate, acetate, chloride, etc.) An exhaust gas purification method is described in which type zeolite is used as a denitration catalyst and liquefied petroleum gas having a composition of propane and butane is used as the reducing agent.
　しかしながら、これらの特許文献２、特許文献３及び特許文献４に記載の脱硝触媒を用いた還元除去法による排ガスの浄化方法でも、排ガス浄化の反応温度が３００℃～５００℃程度で、やはり高いものであるという問題があった。 However, even in the exhaust gas purification methods by the reduction removal method using the denitration catalyst described in Patent Document 2, Patent Document 3, and Patent Document 4, the reaction temperature of exhaust gas purification is as high as about 300 ° C. to 500 ° C. There was a problem of being.
　このように見てくると、船舶用機関の排ガス温度である３００℃以下では、実用的な脱硝触媒性能を有する触媒は、現在のところ見出せていない。 From this point of view, no catalyst having practical denitration catalyst performance has been found at a temperature of 300 ° C. or less, which is the exhaust gas temperature of marine engines.
特開２００７－２２９５５８号公報JP 2007-229558 A 特開２００４－３５８４５４号公報JP 2004-358454 A 特開２００４－２６１７５４号公報JP 2004-261754 A 特開平１１－１８８２３８号公報Japanese Patent Laid-Open No. 11-188238
  本発明の目的は、上記の従来技術の問題を解決し、高濃度の窒素酸化物（ＮＯｘ）および硫黄酸化物（ＳＯｘ）が存在し、しかも排ガス温度が３００℃以下と低い、例えば船舶用機関から排出される燃焼排ガスから、窒素酸化物を効果的に低減することができる、燃焼排ガスの浄化方法、および脱硝触媒を提供することにある。 The object of the present invention is to solve the above-mentioned problems of the prior art, in which high concentrations of nitrogen oxides (NOx) and sulfur oxides (SOx) exist, and the exhaust gas temperature is as low as 300 ° C. or lower, for example, marine engines. An object of the present invention is to provide a method for purifying combustion exhaust gas and a denitration catalyst that can effectively reduce nitrogen oxides from the combustion exhaust gas discharged from the exhaust gas.
  本発明者らは、上記の点に鑑み鋭意研究を重ねた結果、還元剤としてアルコールを添加した燃焼排ガスを、ナトリウム型ゼオライトにコバルト（Ｃｏ）を担持させた触媒に、３００℃以下の温度で接触させることにより、燃焼排ガスから窒素酸化物を効果的に低減できることを見出し、本発明を完成するに至ったものである。 As a result of intensive studies in view of the above points, the inventors of the present invention have obtained a combustion exhaust gas to which alcohol has been added as a reducing agent on a catalyst in which cobalt (Co) is supported on sodium-type zeolite at a temperature of 300 ° C. or lower. It has been found that the nitrogen oxide can be effectively reduced from the combustion exhaust gas by bringing it into contact, and the present invention has been completed.
  上記の目的を達成するために、請求項１の燃焼排ガスの浄化方法の発明は、還元剤としてアルコールを添加した燃焼排ガスを、ナトリウム型ゼオライトにコバルトを担持させた脱硝触媒に、１８０～３００℃の温度において接触させることにより、排ガス中の窒素酸化物を除去することを特徴としている。 In order to achieve the above-mentioned object, the invention of the method for purifying combustion exhaust gas according to claim 1 is directed to applying a combustion exhaust gas to which alcohol as a reducing agent is added to a denitration catalyst in which cobalt is supported on sodium-type zeolite at 180 to 300 ° C. It is characterized in that nitrogen oxides in the exhaust gas are removed by contact at the temperature.
　請求項２の発明は、請求項１に記載の燃焼排ガスの浄化方法であって、脱硝触媒が、ナトリウム型ゼオライトにコバルトおよび水素を担持させた脱硝触媒であることを特徴としている。 The invention of claim 2 is the method for purifying combustion exhaust gas according to claim 1, wherein the denitration catalyst is a denitration catalyst in which cobalt and hydrogen are supported on sodium-type zeolite.
　請求項３の発明は、請求項１に記載の燃焼排ガスの浄化方法であって、脱硝触媒が、ナトリウム型ゼオライトにコバルトおよびアルカリ金属またはアルカリ土類金属を担持させた脱硝触媒であることを特徴としている。 The invention according to claim 3 is the method for purifying combustion exhaust gas according to claim 1, wherein the denitration catalyst is a denitration catalyst in which cobalt and alkali metal or alkaline earth metal are supported on sodium-type zeolite. It is said.
　請求項４の発明は、請求項１～３のうちのいずれか一項に記載の燃焼排ガスの浄化方法であって、還元剤が、イソプロピルアルコール、エタノール、またはメタノールであることを特徴としている。 The invention of claim 4 is the method for purifying combustion exhaust gas according to any one of claims 1 to 3, wherein the reducing agent is isopropyl alcohol, ethanol, or methanol.
　請求項５の発明は、請求項１～３のうちのいずれか一項に記載の燃焼排ガスの浄化方法であって、ナトリウム型ゼオライトが、ＺＳＭ－５（ＭＦＩ）型ゼオライトまたはモルデナイト（ＭＯＲ）型ゼオライトであることを特徴としている。 The invention of claim 5 is the method for purifying combustion exhaust gas according to any one of claims 1 to 3, wherein the sodium type zeolite is a ZSM-5 (MFI) type zeolite or a mordenite (MOR) type. It is characterized by being a zeolite.
　請求項６の発明は、請求項２または３に記載の燃焼排ガスの浄化方法であって、燃焼排ガスが、Ｃ重油を燃焼した排ガスであることを特徴としている。 The invention of claim 6 is the method for purifying combustion exhaust gas according to claim 2 or 3, characterized in that the combustion exhaust gas is an exhaust gas obtained by burning C heavy oil.
　請求項７の発明は、請求項３に記載の燃焼排ガスの浄化方法であって、アルカリ金属が、カリウム（Ｋ）であり、アルカリ土類金属が、カルシウム（Ｃａ）、ストロンチウム（Ｓｒ）、およびバリウム（Ｂａ）よりなる群の中から選ばれた少なくとも１種の金属であることを特徴としている。 The invention according to claim 7 is the method for purifying combustion exhaust gas according to claim 3, wherein the alkali metal is potassium (K), the alkaline earth metal is calcium (Ca), strontium (Sr), and It is characterized by being at least one metal selected from the group consisting of barium (Ba).
　請求項８の発明は、請求項１に記載の燃焼排ガスの浄化方法に使用する脱硝触媒であって、ナトリウム型ゼオライトにコバルトを担持させたものであり、還元剤としてアルコールを添加した燃焼排ガスに対し、１８０～３００℃の温度において接触させることを特徴としている。 The invention of claim 8 is a denitration catalyst used in the method for purifying combustion exhaust gas according to claim 1, wherein cobalt is supported on sodium-type zeolite, and the combustion exhaust gas to which alcohol is added as a reducing agent. On the other hand, the contact is made at a temperature of 180 to 300 ° C.
　請求項９の発明は、請求項８に記載の脱硝触媒であって、脱硝触媒が、ナトリウム型ゼオライトにコバルトおよび水素を担持させた脱硝触媒であることを特徴としている。 The invention according to claim 9 is the denitration catalyst according to claim 8, wherein the denitration catalyst is a denitration catalyst in which cobalt and hydrogen are supported on sodium-type zeolite.
　請求項１０の発明は、請求項８に記載の脱硝触媒であって、脱硝触媒が、ナトリウム型ゼオライトにコバルトおよびアルカリ金属またはアルカリ土類金属を担持させた脱硝触媒であることを特徴としている。 A tenth aspect of the invention is the denitration catalyst according to the eighth aspect, wherein the denitration catalyst is a denitration catalyst in which cobalt and an alkali metal or an alkaline earth metal are supported on a sodium-type zeolite.
　請求項１１の発明は、請求項８～１０のうちのいずれか一項に記載の脱硝触媒であって、ナトリウム型ゼオライトが、ＺＳＭ－５（ＭＦＩ）ゼオライトまたはモルデナイト（ＭＯＲ）ゼオライトからなるものであることを特徴としている。 The invention of claim 11 is the denitration catalyst according to any one of claims 8 to 10, wherein the sodium-type zeolite comprises ZSM-5 (MFI) zeolite or mordenite (MOR) zeolite. It is characterized by being.
　請求項１２の発明は、請求項１０に記載の脱硝触媒であって、アルカリ金属が、カリウム（Ｋ）であり、アルカリ土類金属が、カルシウム（Ｃａ）、ストロンチウム（Ｓｒ）、およびバリウム（Ｂａ）よりなる群の中から選ばれた少なくとも１種の金属であることを特徴としている。 The invention of claim 12 is the denitration catalyst according to claim 10, wherein the alkali metal is potassium (K), and the alkaline earth metal is calcium (Ca), strontium (Sr), and barium (Ba ) At least one metal selected from the group consisting of:
  本発明の燃焼排ガスの浄化方法の発明によれば、高濃度の窒素酸化物（ＮＯｘ）および硫黄酸化物（ＳＯｘ）が存在し、しかも排ガス温度が３００℃以下と低い、例えば船舶用機関すなわち船舶用大型ディーゼルエンジン、工場や発電所、地域冷暖房などの大規模ボイラー等から排出される燃焼排ガスから、窒素酸化物を効果的、かつ効率良く低減することができるという効果を奏する。 According to the invention of the method for purifying combustion exhaust gas of the present invention, high concentrations of nitrogen oxides (NOx) and sulfur oxides (SOx) exist, and the exhaust gas temperature is as low as 300 ° C. or less, for example, marine engines, that is, marine vessels. This produces an effect that nitrogen oxides can be effectively and efficiently reduced from combustion exhaust gas discharged from large-scale diesel engines, large-scale boilers such as factories and power plants, and district heating and cooling.
  また、本発明の燃焼排ガスの浄化方法に使用する脱硝触媒によれば、高濃度の窒素酸化物（ＮＯｘ）および硫黄酸化物（ＳＯｘ）の存在下で、しかも排ガス温度が３００℃以下と低い燃焼排ガスから、窒素酸化物を効果的、かつ効率良く低減することができるという効果を奏する。 Moreover, according to the denitration catalyst used in the method for purifying combustion exhaust gas of the present invention, combustion with a low concentration of nitrogen oxide (NOx) and sulfur oxide (SOx) and an exhaust gas temperature as low as 300 ° C. or less is present. There is an effect that nitrogen oxides can be effectively and efficiently reduced from the exhaust gas.
本発明の実施例において使用した触媒性能評価試験装置のフロー図である。It is a flowchart of the catalyst performance evaluation test apparatus used in the Example of this invention.
  つぎに、本発明の実施の形態を説明するが、本発明はこれらに限定されるものではない。 Next, embodiments of the present invention will be described, but the present invention is not limited thereto.
　本発明による燃焼排ガスの浄化方法は、還元剤としてアルコールを添加した燃焼排ガスを、ナトリウム型ゼオライトにコバルトを担持させた脱硝触媒に、１８０～３００℃の温度において接触させることにより、排ガス中の窒素酸化物を除去することを特徴としている。 The method for purifying combustion exhaust gas according to the present invention comprises contacting a combustion exhaust gas to which alcohol is added as a reducing agent with a denitration catalyst in which cobalt is supported on sodium-type zeolite at a temperature of 180 to 300 ° C. It is characterized by removing oxides.
　本発明の燃焼排ガスの浄化方法に用いる脱硝触媒は、ナトリウム型ゼオライトにコバルトおよび水素を担持させた脱硝触媒、またはナトリウム型ゼオライトにコバルトおよびアルカリ金属またはアルカリ土類金属を担持させた脱硝触媒であってもよい。 The denitration catalyst used in the combustion exhaust gas purification method of the present invention is a denitration catalyst in which cobalt and hydrogen are supported on sodium-type zeolite, or a denitration catalyst in which cobalt and alkali metal or alkaline earth metal are supported on sodium-type zeolite. May be.
　本発明で用いる還元剤であるアルコールとしては特に制限されず、一般的にはイソプロピルアルコール、エタノール、またはメタノールが好ましい。その理由は、完全に酸化されると考えられる炭素が少ないアルコールが良いためである。 The alcohol that is the reducing agent used in the present invention is not particularly limited, and isopropyl alcohol, ethanol, or methanol is generally preferable. The reason is that an alcohol with less carbon that is considered to be completely oxidized is preferable.
　これに対して、前記した特許文献３の実施例に使用されている還元剤である炭化水素は排ガス温度が高い場合にのみ有効である。また、炭化水素は可燃性ガスに指定されており、船舶では可燃性ガスを積載する場合には、安全装置などの設置が必要となるため、船舶機関排ガスの浄化方法の還元剤としては不都合である。 On the other hand, the hydrocarbon, which is the reducing agent used in the example of Patent Document 3 described above, is effective only when the exhaust gas temperature is high. In addition, hydrocarbons are designated as flammable gases, and when a flammable gas is loaded on a ship, it is necessary to install a safety device or the like. is there.
　本発明の燃焼排ガスの浄化方法に使用する脱硝触媒は、－７以下のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトにコバルト（Ｃｏ）を担持させたもの、あるいは同ナトリウム型ゼオライトにコバルトおよび水素を担持させたもの、あるいはまた同ナトリウム型ゼオライトにコバルトおよびアルカリ金属またはアルカリ土類金属を担持させたものであることが好ましい。 The denitration catalyst used in the method for purifying combustion exhaust gas of the present invention is a catalyst in which cobalt (Co) is supported on sodium-type zeolite having an acid strength corresponding to Hammett's acidity function H 0 of −7 or less, or the sodium-type catalyst It is preferable that cobalt and hydrogen are supported on zeolite, or that cobalt and an alkali metal or alkaline earth metal are supported on the sodium-type zeolite.
　ここで、ハメットの酸度関数Ｈ０とは、固体酸表面の酸点が塩基にプロトンを与える能力（ブレンステッド酸性）あるいは塩基から電子対を受け取る能力（ルイス酸性）で定義され、ｐＫａ値で表わされるものであり、既知の指示薬法あるいは気体塩基吸着法等の方法で測定することができる。例えば、酸点へアンモニアが吸着する際の熱量を測定することにより、酸強度分布を測定するアンモニア吸着熱法を用いて測定することができる。 Here, Hammett's acidity function H 0 is defined by the ability of an acid point on the surface of a solid acid to give a proton to a base (Bronsted acidity) or the ability to receive an electron pair from a base (Lewis acidity), and is expressed by a pKa value. It can be measured by a known indicator method or gas base adsorption method. For example, by measuring the amount of heat when ammonia is adsorbed to the acid point, it can be measured using an ammonia adsorption heat method for measuring the acid strength distribution.
　そして、ゼオライトのハメットの酸強度Ｈ０は、ゼオライトの組成比、ゼオライトの調製方法、ゼオライトの構造により変わる。 The acid strength H 0 of the Hammett of zeolite varies depending on the composition ratio of the zeolite, the preparation method of the zeolite, and the structure of the zeolite.
　また、ゼオライトのハメットの酸強度Ｈ０はゼオライトの構造により、モルデナイト（ＭＯＲ）＜ＺＳＭ－５（ＭＦＩ）＜ＢＥＡ（β）＜Ｙのように決まる。 The acid strength H 0 of the Hammett of zeolite is determined by the structure of the zeolite such that mordenite (MOR) <ZSM-5 (MFI) <BEA (β) <Y.
　従って、本発明による脱硝触媒において、ナトリウム型ゼオライトは、ＺＳＭ－５（ＭＦＩ）ゼオライトまたはモルデナイト（ＭＯＲ）ゼオライトからなるものであることが好ましい。 Therefore, in the denitration catalyst according to the present invention, the sodium-type zeolite is preferably composed of ZSM-5 (MFI) zeolite or mordenite (MOR) zeolite.
　前記した特許文献３に記載するプロトン型βゼオライトにＣｏを担時した触媒には、触媒表面にＨとＣｏの酸点が存在する。本発明である－７以下のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトにＣｏを担時した触媒には、触媒表面にＮａとＣｏの酸点が存在する。そして、酸点の強さは、Ｈ＞Ｃｏ＞Ｎａであり、酸点が強いほど還元剤であるエタノールが反応しやすいと考えられる。そのため、プロトン型では、脱硝反応とは関係のないプロトンとエタノールの反応が起こり、エタノールが余分に消費される可能性がある。ナトリウム型ゼオライトを用いることで、エタノールの余分な消費が抑えられ、性能が向上する。 The catalyst in which Co is supported on the proton-type β zeolite described in Patent Document 3 described above has acid sites of H and Co on the catalyst surface. In the present invention, a catalyst in which Co is supported on a sodium-type zeolite having an acid strength corresponding to Hammett acidity function H 0 of −7 or less has acid sites of Na and Co on the catalyst surface. The strength of the acid point is H>Co> Na, and it is considered that the stronger the acid point, the more easily the ethanol that is the reducing agent reacts. For this reason, in the proton type, a reaction between protons and ethanol unrelated to the denitration reaction occurs, and ethanol may be consumed excessively. By using sodium-type zeolite, excessive consumption of ethanol is suppressed, and the performance is improved.
　本発明による脱硝触媒は、還元剤としてアルコールを添加した燃焼排ガスに対し、１８０～３００℃の温度において接触させる。 The denitration catalyst according to the present invention is brought into contact with combustion exhaust gas to which alcohol is added as a reducing agent at a temperature of 180 to 300 ° C.
　ここで、本発明の触媒によれば、排ガスの温度が１８０～３００℃ 程度の比較的低温であっても、窒素酸化物の優れた除去性能が得られる。また、船舶用排ガス温度は煙道にて約１６０℃になると、船舶用排ガスに含まれる硫黄酸化物（ＳＯｘ）が無水硫酸となり、水分と結合して硫酸（Ｈ２ＳＯ４）となって凝縮付着し金属を腐食させる現象（を低温腐食の問題）が発生するために好ましくない。従って通常、船舶用排ガス温度は１８０℃以下にさせることはなく、本発明による脱硝触媒は、還元剤としてアルコールを添加した燃焼排ガスに対し、１８０℃以上であることが好ましい。 Here, according to the catalyst of the present invention, excellent nitrogen oxide removal performance can be obtained even when the temperature of the exhaust gas is relatively low, such as about 180 to 300 ° C. When the exhaust gas temperature for ships reaches about 160 ° C in the flue, the sulfur oxide (SOx) contained in the exhaust gas for ships becomes anhydrous sulfuric acid, which combines with moisture and becomes sulfuric acid (H 2 SO 4 ). This is not preferable because a phenomenon that adheres and corrodes metal (a problem of low temperature corrosion) occurs. Therefore, usually, the temperature of the exhaust gas for ships is not set to 180 ° C. or lower, and the denitration catalyst according to the present invention is preferably 180 ° C. or higher with respect to the combustion exhaust gas to which alcohol is added as a reducing agent.
　本発明の燃焼排ガスの浄化方法に使用する脱硝触媒の製造方法は、つぎの通りである。 The manufacturing method of the denitration catalyst used in the method for purifying combustion exhaust gas of the present invention is as follows.
　まず、脱硝触媒が、－７以下のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトにコバルト（Ｃｏ）を担持させたものである場合には、ＺＳＭ－５（ＭＦＩ）型ゼオライトまたはモルデナイト（ＭＯＲ）型ゼオライトを、例えば硝酸コバルト［Ｃｏ（ＮＯ３）２］、酢酸コバルト［Ｃｏ（Ｃ２Ｈ３Ｏ２）２］、塩化コバルト［ＣｏＣｌ２］、蟻酸コバルト［ＣｏＣ４Ｈ１４Ｏ８）］等のコバルト化合物の水溶液に入れて、温度７０～９０℃で、２～２４時間攪拌した後、濾過して洗浄し、ついで温度１００～１２０℃で、１～４時間乾燥し、さらに温度４５０～５５０℃で３～５時間焼成することにより、コバルト（Ｃｏ）イオン交換ゼオライトよりなる本発明の脱硝触媒を生成する。本発明による脱硝触媒のＣｏ担持量は、２～４重量％であることが好ましい。 First, when the denitration catalyst is obtained by loading cobalt (Co) on sodium-type zeolite having acid strength corresponding to Hammett acidity function H 0 of −7 or less, ZSM-5 (MFI) -type zeolite Or a mordenite (MOR) type zeolite is used, for example, cobalt nitrate [Co (NO 3 ) 2 ], cobalt acetate [Co (C 2 H 3 O 2 ) 2 ], cobalt chloride [CoCl 2 ], cobalt formate [CoC 4 H 14. In an aqueous solution of a cobalt compound such as O 8 )], stirred at a temperature of 70 to 90 ° C. for 2 to 24 hours, filtered and washed, and then dried at a temperature of 100 to 120 ° C. for 1 to 4 hours. Further, the denitration catalyst of the present invention made of cobalt (Co) ion-exchanged zeolite is produced by calcining at a temperature of 450 to 550 ° C. for 3 to 5 hours. The amount of Co supported by the denitration catalyst according to the present invention is preferably 2 to 4% by weight.
　ここで、ナトリウム型ゼオライトに対するコバルトイオンの担持量が２重量％未満であれば、担持量が少なく、つまり活性点が少なすぎるため、好ましくない。また、コバルトイオンの担持量が４重量％を超えると、脱硝反応に寄与しない、表面のＣｏ酸化物の割合が多くなるので、好ましくない。 Here, if the amount of cobalt ions supported on the sodium-type zeolite is less than 2% by weight, the amount supported is small, that is, the number of active sites is too small. On the other hand, if the amount of cobalt ions supported exceeds 4% by weight, the proportion of Co oxide on the surface that does not contribute to the denitration reaction increases, which is not preferable.
　また脱硝触媒が、－７以下のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトにコバルトおよび水素を担持させたものである場合には、ＺＳＭ－５（ＭＦＩ）ゼオライトまたはモルデナイト（ＭＯＲ）ゼオライトを、硝酸アンモニウム（ＮＨ４ＮＯ３）の水溶液に入れ、温度７０～９０℃で、２～２４時間攪拌した後、濾過して洗浄する。ついで、濾過洗浄物を、温度１００～１２０℃で、１～４時間乾燥し、ＮＨ４－ＭＦＩゼオライトまたはＮＨ４－ＭＯＲゼオライトを得る。 Further, when the denitration catalyst is obtained by loading cobalt and hydrogen on sodium-type zeolite having an acid strength corresponding to Hammett acidity function H 0 of −7 or less, ZSM-5 (MFI) zeolite or mordenite ( The MOR) zeolite is placed in an aqueous solution of ammonium nitrate (NH 4 NO 3 ), stirred at a temperature of 70-90 ° C. for 2-24 hours, then filtered and washed. The filtered washing is then dried at a temperature of 100 to 120 ° C. for 1 to 4 hours to obtain NH 4 -MFI zeolite or NH 4 -MOR zeolite.
　その後、ＮＨ４－ＭＦＩゼオライトまたはＮＨ４－ＭＯＲゼオライトを、例えば硝酸コバルト［Ｃｏ（ＮＯ３）２］、酢酸コバルト［Ｃｏ（Ｃ２Ｈ３Ｏ２）２］、塩化コバルト［ＣｏＣｌ２］、蟻酸コバルト［ＣｏＣ４Ｈ１４Ｏ８）］等のコバルト化合物の水溶液に入れて、温度７０～９０℃で、２～２４時間攪拌した後、濾過して洗浄する。ついで、濾過洗浄物を、温度１００～１２０℃で、１～４時間乾燥し、さらに温度４５０～５５０℃で、３～５時間焼成することにより、Ｃｏ／Ｈ－ＭＦＩゼオライトまたはＣｏ／Ｈ－ＭＯＲゼオライトを生成する。 Thereafter, NH 4 -MFI zeolite or NH 4 -MOR zeolite is converted into, for example, cobalt nitrate [Co (NO 3 ) 2 ], cobalt acetate [Co (C 2 H 3 O 2 ) 2 ], cobalt chloride [CoCl 2 ], formic acid. It is placed in an aqueous solution of a cobalt compound such as cobalt [CoC 4 H 14 O 8 ), stirred at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then filtered and washed. Subsequently, the filtered and washed product is dried at a temperature of 100 to 120 ° C. for 1 to 4 hours, and further calcined at a temperature of 450 to 550 ° C. for 3 to 5 hours, whereby a Co / H-MFI zeolite or Co / H-MOR is obtained. Zeolite is produced.
　本発明による脱硝触媒において、Ｃｏ担持量は、１～４重量％であることが好ましい。 In the denitration catalyst according to the present invention, the Co loading is preferably 1 to 4% by weight.
　ここで、コバルトイオンの担持量が１重量％未満であれば、担持量が少なく、つまり活性点が少なすぎるため、好ましくない。またコバルトイオンの担持量が４重量％を超えると、脱硝反応に寄与しない、表面のＣｏ酸化物の割合が多くなるので、好ましくない。 Here, if the loading amount of cobalt ions is less than 1% by weight, the loading amount is small, that is, the number of active sites is too small. On the other hand, if the amount of cobalt ions supported exceeds 4% by weight, the proportion of Co oxide on the surface that does not contribute to the denitration reaction increases, which is not preferable.
　また、脱硝触媒が、ナトリウム型ゼオライトにコバルトおよびアルカリ金属またはアルカリ土類金属を担持させたものである場合には、ＺＳＭ－５（ＭＦＩ）ゼオライトまたはモルデナイト（ＭＯＲ）ゼオライトを、アルカリ金属またはアルカリ土類金属の水溶液に入れ、温度７０～９０℃で、２～２４時間攪拌した後、濾過して洗浄する。ついで、濾過洗浄物を、温度１００～１２０℃で、１～４時間乾燥し、アルカリ金属またはアルカリ土類金属イオン交換のゼオライトを得た。 Further, when the denitration catalyst is a sodium type zeolite in which cobalt and alkali metal or alkaline earth metal are supported, ZSM-5 (MFI) zeolite or mordenite (MOR) zeolite is replaced with alkali metal or alkaline earth. It is put into an aqueous solution of a metal, stirred at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then filtered and washed. The filtered and washed product was then dried at a temperature of 100 to 120 ° C. for 1 to 4 hours to obtain an alkali metal or alkaline earth metal ion exchange zeolite.
　ここで、アルカリ金属としては、カリウム（Ｋ）が挙げられ、アルカリ土類金属としては、カルシウム（Ｃａ）、ストロンチウム（Ｓｒ）、およびバリウム（Ｂａ）よりなる群の中から選ばれた少なくとも１種の金属が挙げられる。 Here, the alkali metal includes potassium (K), and the alkaline earth metal is at least one selected from the group consisting of calcium (Ca), strontium (Sr), and barium (Ba). These metals are mentioned.
　そして、ナトリウム型のゼオライトにアルカリ金属またはアルカリ土類金属を担持させるには、例えばアルカリ金属またはアルカリ土類金属の硝酸水溶液、酢酸水溶液、塩化水溶液、蟻酸水溶液等が利用できる。 In order to support an alkali metal or alkaline earth metal on sodium-type zeolite, for example, an aqueous solution of nitric acid, aqueous solution of acetic acid, aqueous solution of chloride, aqueous solution of formic acid or the like of an alkali metal or alkaline earth metal can be used.
　その後、アルカリ金属またはアルカリ土類金属イオン交換ゼオライトを、例えば硝酸コバルト［Ｃｏ（ＮＯ３）２］、酢酸コバルト［Ｃｏ（Ｃ２Ｈ３Ｏ２）２］、塩化コバルト［ＣｏＣｌ２］、蟻酸コバルト［ＣｏＣ４Ｈ１４Ｏ８）］等のコバルト化合物の水溶液に入れて、温度７０～９０℃で、２～２４時間攪拌した後、濾過して洗浄する。ついで、濾過洗浄物を、温度１００～１２０℃で、１～４時間乾燥し、さらに温度４５０～５５０℃で、３～５時間焼成することにより、Ｃｏ／アルカリ金属またはアルカリ土類金属イオン交換ゼオライトよりなる本発明の脱硝触媒を生成する。 Thereafter, an alkali metal or alkaline earth metal ion-exchanged zeolite is converted into, for example, cobalt nitrate [Co (NO 3 ) 2 ], cobalt acetate [Co (C 2 H 3 O 2 ) 2 ], cobalt chloride [CoCl 2 ], cobalt formate. It is put in an aqueous solution of a cobalt compound such as [CoC 4 H 14 O 8 )], stirred at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then washed by filtration. The filtered and washed product is then dried at a temperature of 100 to 120 ° C. for 1 to 4 hours, and further calcined at a temperature of 450 to 550 ° C. for 3 to 5 hours, whereby a Co / alkali metal or alkaline earth metal ion exchange zeolite is obtained. The denitration catalyst of the present invention is produced.
　本発明による脱硝触媒において、アルカリ金属またはアルカリ土類金属の担持量は、１～４重量％であることが好ましい。 In the denitration catalyst according to the present invention, the supported amount of alkali metal or alkaline earth metal is preferably 1 to 4% by weight.
　ここで、アルカリ金属またはアルカリ土類金属のイオンの担持量が１重量％未満であれば、担持量が少なく、つまり活性点が少なすぎるため、好ましくない。またアルカリ金属またはアルカリ土類金属のイオンの担持量が４重量％を超えると、脱硝反応に寄与しない、表面のアルカリ金属またはアルカリ土類金属の酸化物の割合が多くなるので、好ましくない。 Here, if the supported amount of ions of alkali metal or alkaline earth metal is less than 1% by weight, it is not preferable because the supported amount is small, that is, there are too few active points. On the other hand, if the supported amount of alkali metal or alkaline earth metal ions exceeds 4% by weight, the ratio of surface alkali metal or alkaline earth metal oxides that do not contribute to the denitration reaction increases, which is not preferable.
　一方、本発明による脱硝触媒において、Ｃｏ担持量は、１～４重量％であることが好ましい。ここで、コバルトイオンの担持量が１重量％未満であれば、担持量が少なく、つまり活性点が少なすぎるため、好ましくない。またコバルトイオンの担持量が４重量％を超えると、脱硝反応に寄与しない、表面のＣｏ酸化物の割合が多くなるので、好ましくない。 On the other hand, in the denitration catalyst according to the present invention, the Co loading is preferably 1 to 4% by weight. Here, if the amount of cobalt ions supported is less than 1% by weight, the amount supported is small, that is, the number of active sites is too small, which is not preferable. On the other hand, if the amount of cobalt ions supported exceeds 4% by weight, the proportion of Co oxide on the surface that does not contribute to the denitration reaction increases, which is not preferable.
　本発明の燃焼排ガスの浄化方法に使用する脱硝触媒は、例えばハニカム構造体に対してナトリウム型ゼオライトおよびコバルトを担持させて、ハニカム型脱硝触媒として製造することもできる。 The denitration catalyst used in the method for purifying combustion exhaust gas of the present invention can be manufactured as a honeycomb type denitration catalyst by, for example, supporting sodium-type zeolite and cobalt on a honeycomb structure.
　まず、ガラスペーパーに、ナトリウム型ゼオライトと水とシリカゾルとからなるスラリーを塗布する工程を実施して、ハニカム構造体を作製するための基材を作製する。 First, a base material for manufacturing a honeycomb structure is manufactured by applying a slurry made of sodium-type zeolite, water, and silica sol to glass paper.
　つぎに、上記のナトリウム型ゼオライト担持基材を波形に加工して波板状基材を得る工程と、上記の基材を平板に加工して平板状基材を得る工程と、該波板状基材と該平板状基材と交互に積層する工程を実施して、ハニカム構造体を作製する。 Next, the step of obtaining a corrugated plate-like substrate by processing the sodium-type zeolite-supporting substrate into a corrugated shape, the step of obtaining the flat plate-like substrate by processing the above-mentioned substrate into a flat plate, and the corrugated shape A honeycomb structure is manufactured by carrying out a step of alternately laminating the substrate and the flat substrate.
　そして、脱硝触媒が、－７以下のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトにコバルト（Ｃｏ）を担持させたものである場合には、さらに、上記の方法により作製されたナトリウム型ゼオライト担持ハニカム構造体に対してコバルトをイオン交換させる工程を実施して、ハニカム型脱硝触媒を作製する。 Further, when the denitration catalyst is obtained by loading cobalt (Co) on sodium-type zeolite having an acid strength corresponding to Hammett acidity function H 0 of −7 or less, it is further prepared by the above method. The honeycomb type denitration catalyst is manufactured by carrying out a step of ion exchange of cobalt on the sodium type zeolite supporting honeycomb structure.
　あるいはまた、上記のナトリウム型ゼオライト担持基材を波形に加工して波板状基材を得る工程と、上記の基材を平板に加工して平板状基材を得る工程と、該波板状基材に対しコバルトをイオン交換させて波板状触媒を得る工程と、該平板状基材に対しコバルトをイオン交換させて平板状触媒を得る工程と、該波板状触媒と該平板状触媒を交互に積層する工程を実施して、ハニカム型脱硝触媒を作製する。 Alternatively, the above-mentioned sodium-type zeolite-supporting base material is processed into a corrugated shape to obtain a corrugated plate-like base material, the above-mentioned base material is processed into a flat plate to obtain a flat base-like base material, A step of obtaining a corrugated catalyst by ion-exchanging cobalt to a base material; a step of obtaining a flat catalyst by ion-exchanging cobalt to the flat base material; and the corrugated catalyst and the flat catalyst. A honeycomb type denitration catalyst is manufactured by alternately stacking layers.
　また脱硝触媒が、－７以下のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトにコバルトおよび水素を担持させたものである場合には、さらに、上記の方法により作製されたナトリウム型ゼオライト担持ハニカム構造体に対してコバルトおよび水素をイオン交換させる工程を実施して、ハニカム型脱硝触媒を作製する。 Further, when the denitration catalyst is obtained by loading cobalt and hydrogen on a sodium-type zeolite having an acid strength corresponding to Hammett acidity function H 0 of −7 or less, sodium produced by the above method is further used. A honeycomb-type denitration catalyst is manufactured by performing an ion exchange process of cobalt and hydrogen on the honeycomb structure supporting a zeolite.
　あるいはまた、上記のナトリウム型ゼオライト担持基材を波形に加工して波板状基材を得る工程と、上記の基材を平板に加工して平板状基材を得る工程と、該波板状基材に対しコバルトおよび水素をイオン交換させて波板状触媒を得る工程と、該平板状基材に対しコバルトおよび水素をイオン交換させて平板状触媒を得る工程と、該波板状触媒と該平板状触媒を交互に積層する工程を実施して、ハニカム型脱硝触媒を作製する。 Alternatively, the above-mentioned sodium-type zeolite-supporting base material is processed into a corrugated shape to obtain a corrugated plate-like base material, the above-mentioned base material is processed into a flat plate to obtain a flat base-like base material, A step of obtaining a corrugated catalyst by ion-exchanging cobalt and hydrogen with respect to a base material; a step of obtaining a flat catalyst by ion-exchanging cobalt and hydrogen with respect to the flat base material; and the corrugated catalyst; A step of alternately laminating the flat catalyst is carried out to produce a honeycomb type denitration catalyst.
　また、脱硝触媒が、ナトリウム型ゼオライトにコバルトおよびアルカリ金属またはアルカリ土類金属を担持させたものである場合には、さらに、上記の方法により作製されたナトリウム型ゼオライト担持ハニカム構造体に対してコバルトおよびアルカリ金属またはアルカリ土類金属をイオン交換させる工程を実施して、ハニカム型脱硝触媒を作製する。 Further, when the denitration catalyst is obtained by supporting cobalt and an alkali metal or alkaline earth metal on sodium-type zeolite, the catalyst is further added to the sodium-type zeolite-supported honeycomb structure manufactured by the above method. And a step of ion exchange of alkali metal or alkaline earth metal is performed to produce a honeycomb-type denitration catalyst.
　あるいはまた、上記のナトリウム型ゼオライト担持基材を波形に加工して波板状基材を得る工程と、上記の基材を平板に加工して平板状基材を得る工程と、該波板状基材に対しコバルトおよびアルカリ金属またはアルカリ土類金属をイオン交換させて波板状触媒を得る工程と、該平板状基材に対しコバルトおよびアルカリ金属またはアルカリ土類金属をイオン交換させて平板状触媒を得る工程と、該波板状触媒と該平板状触媒を交互に積層する工程を実施して、ハニカム型脱硝触媒を作製する。 Alternatively, the above-mentioned sodium-type zeolite-supporting base material is processed into a corrugated shape to obtain a corrugated plate-like base material, the above-mentioned base material is processed into a flat plate to obtain a flat base-like base material, A step of obtaining a corrugated plate catalyst by ion-exchanging cobalt and an alkali metal or an alkaline earth metal with respect to a substrate, and a plate shape by ion-exchanging cobalt and an alkali metal or an alkaline earth metal with respect to the plate-like substrate. A step of obtaining a catalyst and a step of alternately laminating the corrugated catalyst and the flat plate catalyst are carried out to produce a honeycomb type denitration catalyst.
　このように、ガラスペーパーに、シリカゾルなどの無機バインダを用いてナトリウム型ゼオライトを固定し、これを成型することでハニカム構造体等の所望の形状のものを得ることができる。 As described above, a sodium-type zeolite is fixed to glass paper using an inorganic binder such as silica sol, and a desired shape such as a honeycomb structure can be obtained by molding this.
　そして、この場合、濃度の高いスラリーを用いても目詰まりが生じるおそれがないので、濃度の高いスラリーを用いることができ、ナトリウム型ゼオライトを担持させる操作は１回で済む。また、基材上でナトリウム型ゼオライトを生成させる方法とは異なり、すでに調製されたナトリウム型ゼオライトを担持させるためナトリウム型ゼオライト生成に必要な高温、高圧条件を必要とせず、一般的な焼成炉であれば十分に作製可能である。 In this case, since there is no possibility of clogging even when a high concentration slurry is used, the high concentration slurry can be used, and the operation of supporting the sodium-type zeolite is only required once. Also, unlike the method of generating sodium-type zeolite on the substrate, it does not require the high-temperature and high-pressure conditions required for sodium-type zeolite generation because it supports already prepared sodium-type zeolite. If there is, it can be sufficiently produced.
　また、作製したナトリウム型ゼオライト担持ハニカムに触媒成分の金属を担持させる場合にも、成型された担体であるため固液分離が容易にできる利点がある。 Also, when the catalyst component metal is supported on the manufactured sodium-type zeolite-supporting honeycomb, the solid support is advantageous because it is a molded support.
　ここで、ハニカム構造体を作製するための基材の作製から、最終的にハニカム型脱硝触媒を作製するまでの工程を、具体的に説明すれば、つぎの通りである。
（基材の調製）
　まず、ナトリウム型ゼオライト、水およびシリカゾルを混合してスラリーを作製する。 Here, the steps from the production of the base material for producing the honeycomb structure to the final production of the honeycomb type denitration catalyst will be specifically described as follows.
(Preparation of base material)
First, a sodium-type zeolite, water and silica sol are mixed to prepare a slurry.
　本発明による脱硝触媒において、ナトリウム型ゼオライトは、ＺＳＭ－５（ＭＦＩ）ゼオライトまたはモルデナイト（ＭＯＲ）ゼオライトからなるものであることが好ましい。 In the denitration catalyst according to the present invention, the sodium-type zeolite is preferably made of ZSM-5 (MFI) zeolite or mordenite (MOR) zeolite.
　シリカゾルとしては、シリカを２０重量%程度含む酸性タイプのものを用いることが可能である。 As the silica sol, an acidic type containing about 20% by weight of silica can be used.
　また、スラリーを作製するに際して、ナトリウム型ゼオライト、水、およびシリカゾルの重量比は、例えば、１００：１００：４６に調整される。 In preparing the slurry, the weight ratio of the sodium-type zeolite, water, and silica sol is adjusted to, for example, 100: 100: 46.
　ついで、こうして得られたスラリーをガラスペーパーに塗布する。このようなスラリーに含まれるシリカゾルは無機バインダとして機能し、コルゲート加工した場合に、波形の形状を保持することが可能であり、目的とする、コルゲート加工が可能な、ハニカム構造体を作製するための基材を得ることができる。 Next, the slurry thus obtained is applied to glass paper. Silica sol contained in such a slurry functions as an inorganic binder, and when corrugated, it can retain the corrugated shape and is intended to produce a honeycomb structure that can be corrugated. The base material can be obtained.
　ナトリウム型ゼオライト、水およびシリカゾルを混合して得られるスラリーを塗布するに際しては、従来公知の任意の方法を用いてよいが、例えば、いわゆるどぶ漬け方法、刷毛塗り方法、スプレー塗り方法、滴下塗布方法等が挙げられる。 In applying a slurry obtained by mixing sodium-type zeolite, water and silica sol, any conventionally known method may be used. For example, a so-called soaking method, brush coating method, spray coating method, dropping coating method Etc.
　以上のようにしてナトリウム型ゼオライトが担持された平板状の基材が得られる。このように平板状のガラスペーパーに対してスラリーを塗布するので、スラリー濃度が高い場合に目詰まりが生じるおそれがなく、当初から高濃度のスラリーを塗布に用いることができ、１回の担持操作でナトリウム型ゼオライト担持基材を得ることができる。
（基材の成型加工）
　上記のようなナトリウム型ゼオライト担持基材は、コルゲータを用いて波形に成型することが可能であり、他方で、スラリーを塗布することにより加えられるシリカゾル等の無機バインダがガラスペーパーのバインダの役目を果たすことになり、ガラスペーパーの成型後に波形を保持することが可能になる。したがって、上記のナトリウム型ゼオライト担持基材は、ハニカム構造体を作製するのに適した材料である。 As described above, a flat substrate on which sodium-type zeolite is supported is obtained. Since the slurry is applied to the flat glass paper in this way, there is no possibility of clogging when the slurry concentration is high, and a high concentration slurry can be used for the application from the beginning, and a single carrying operation. A sodium-type zeolite-supporting substrate can be obtained.
(Base material molding)
The sodium-type zeolite supporting substrate as described above can be formed into a corrugated shape using a corrugator. On the other hand, an inorganic binder such as silica sol added by applying slurry serves as a binder for glass paper. As a result, the corrugation can be maintained after the glass paper is molded. Therefore, the sodium-type zeolite-supporting base material is a material suitable for producing a honeycomb structure.
　上記のナトリウム型ゼオライト担持基材を用いてハニカム構造体を作製する場合、上記ナトリウム型ゼオライト担持基材に対する加工処理として種々の方法が考えられるが、その一方法として、上記基材をコルゲート加工処理にて波形に成型してこれを波板状基材とし、複数の波板状基材と、成型加工処理を施していない平坦な表面形状を有する複数の平板状基材とを交互に積層するようにしてハニカム構造を形成するようにする方法が挙げられる。 When producing a honeycomb structure using the above-mentioned sodium-type zeolite-supporting base material, various methods can be considered as processing for the sodium-type zeolite-supporting base material. As one method, the base material is corrugated. To form a corrugated base material, and alternately stack a plurality of corrugated base materials and a plurality of flat base materials having a flat surface shape that has not been subjected to molding processing. Thus, there is a method for forming a honeycomb structure.
　上記のナトリウム型ゼオライト担持基材を波板状にする方法としては従来公知の種々の方法が用いられてよいが、例えば、波形の外周囲を有する歯車状の円盤上に上記のナトリウム型ゼオライト担持基材を回転移動させることによりこの円盤が有する外周囲の波形形状に沿った波板を得ることができる。あるいは、所定の形状を有する凹溝を有する金属パネルよりなる金型を使用し、金型状に載置したナトリウム型ゼオライト担持基材を、押さえ治具により金型の凹溝に沿って押さえつけて成型することも可能である。 Various methods known in the art may be used for corrugating the sodium-type zeolite-supporting substrate. For example, the sodium-type zeolite is supported on a gear-shaped disk having a corrugated outer periphery. By rotating the substrate, it is possible to obtain a corrugated plate along the outer peripheral waveform of the disk. Alternatively, a metal panel having a groove having a predetermined shape is used, and the sodium-type zeolite-supporting substrate placed in the mold is pressed along the groove of the mold by a pressing jig. It is also possible to mold.
　ついで、成型後の波板状基材に対して乾燥処理工程を行う。その際の条件は、特に限定されるものではないが、例えば、空気雰囲気下１１０～３００℃の温度に１時間～３時間の期間にわたって置かれる。 Next, a drying process is performed on the corrugated substrate after molding. The conditions at that time are not particularly limited, but, for example, they are placed in an air atmosphere at a temperature of 110 to 300 ° C. for a period of 1 to 3 hours.
　上記のようにして得られた平板状基材および波板状基材は、焼成工程に付される。その際の条件は、特に限定されるものではないが、例えば、空気雰囲気下５００～５５０℃の温度に３時間にわたって置かれる。 The flat substrate and corrugated substrate obtained as described above are subjected to a firing step. The conditions at that time are not particularly limited. For example, the film is placed in an air atmosphere at a temperature of 500 to 550 ° C. for 3 hours.
　上記の乾燥後の平板用の基材を回転移動させる円盤は、ハニカム構造体を作製するに際しては、平板状基材と波板状基材が交互に配置されることになるので、波板用の円盤と並置させておくのが便利である。 The disk that rotates and moves the flat plate base material after drying has a flat plate-like substrate and a corrugated plate-like substrate that are alternately arranged when the honeycomb structure is manufactured. It is convenient to place it side by side with the disk.
　上記のように加工された波板状基材と平板状基材とを交互に積層することによりハニカム構造体を得ることができる。このハニカム構造体において、各平板状基材と波板状基材とは互いに接触している状態を保っていればよく、接触面にて接着させておいても、接着させずに、ケーシング等に納めることによりその接触状態を維持するようにさせてもよい。
（ハニカム型脱硝触媒の作製）
　上記のようにして得られたハニカム構造体に触媒活性を有するコバルトを担持させることによりハニカム型脱硝触媒を得ることができる。 A honeycomb structure can be obtained by alternately laminating the corrugated substrate and the flat substrate processed as described above. In this honeycomb structure, each flat plate-like substrate and corrugated plate-like substrate need only be kept in contact with each other. It is also possible to maintain the contact state by placing it in the box.
(Preparation of honeycomb type denitration catalyst)
A honeycomb denitration catalyst can be obtained by supporting cobalt having catalytic activity on the honeycomb structure obtained as described above.
　まず、本発明においては、－７以下のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトにコバルトを担持させる。 First, in the present invention, cobalt is supported on a sodium-type zeolite having an acid strength corresponding to Hammett acidity function H 0 of −7 or less.
　上記のようなコバルトをナトリウム型ゼオライト上に担持させるためのイオン交換を行うに際して、上記のＺＳＭ－５（ＭＦＩ）型ゼオライトまたはモルデナイト（ＭＯＲ）型ゼオライトを担持したハニカム構造体は、例えば硝酸コバルト［Ｃｏ（ＮＯ３）２］、酢酸コバルト［Ｃｏ（Ｃ２Ｈ３Ｏ２）２］、塩化コバルト［ＣｏＣｌ２］、蟻酸コバルト［ＣｏＣ４Ｈ１４Ｏ８）］等のコバルト化合物の水溶液に入れて、温度７０～９０℃で、２～２４時間浸漬した後、洗浄し、ついで温度１００～１２０℃で、１～４時間乾燥し、さらに温度４５０～５５０℃で３～５時間焼成することにより、コバルト（Ｃｏ）イオン交換ゼオライトを生成し、本発明の脱硝触媒を担持したハニカム構造体、すなわちハニカム型脱硝触媒が得られる。本発明による脱硝触媒のＣｏ担持量は、２～４重量％であることが好ましい。 When performing ion exchange for supporting cobalt on sodium-type zeolite as described above, a honeycomb structure supporting the above ZSM-5 (MFI) -type zeolite or mordenite (MOR) -type zeolite is, for example, cobalt nitrate [ Put in an aqueous solution of a cobalt compound such as Co (NO 3 ) 2 ], cobalt acetate [Co (C 2 H 3 O 2 ) 2 ], cobalt chloride [CoCl 2 ], cobalt formate [CoC 4 H 14 O 8 )]. By immersing at a temperature of 70 to 90 ° C. for 2 to 24 hours, washing, then drying at a temperature of 100 to 120 ° C. for 1 to 4 hours, and further firing at a temperature of 450 to 550 ° C. for 3 to 5 hours, A honeycomb structure carrying cobalt (Co) ion-exchanged zeolite and carrying the denitration catalyst of the present invention, that is, a honeycomb type denitration catalyst is obtained. It is. The amount of Co supported by the denitration catalyst according to the present invention is preferably 2 to 4% by weight.
　なおここで、前述のように、ガラスペーパーに、ナトリウム型ゼオライトと水とシリカゾルとからなるスラリーを塗布する工程を実施して、ハニカム構造体を作製するための基材を作製し、つぎに、このナトリウム型ゼオライト担持基材を波形に加工して波板状基材を得る工程と、上記の基材を平板に加工して平板状基材を得る工程と、該波板状基材に対しコバルトをイオン交換させて波板状触媒を得る工程と、該平板状基材に対しコバルトをイオン交換させて平板状触媒を得る工程と、該波板状触媒と該平板状触媒を交互に積層する工程を実施して、ハニカム型脱硝触媒を作製するようにしてもよい。 Here, as described above, a step of applying a slurry made of sodium-type zeolite, water, and silica sol to glass paper is carried out to produce a substrate for producing a honeycomb structure, Processing the sodium-type zeolite-supporting base material into a corrugated shape to obtain a corrugated base material, processing the base material into a flat plate to obtain a flat base material, and the corrugated base material. A step of obtaining a corrugated catalyst by ion-exchanging cobalt, a step of obtaining a flat catalyst by ion-exchanging cobalt to the flat substrate, and laminating the corrugated catalyst and the flat catalyst alternately. This step may be carried out to produce a honeycomb-type denitration catalyst.
　つぎに、本発明においては、－７以下のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトにコバルトおよび水素を担持させることによりハニカム型脱硝触媒を得ることができる。 Next, in the present invention, a honeycomb type denitration catalyst can be obtained by supporting cobalt and hydrogen on a sodium type zeolite having an acid strength corresponding to Hammett acidity function H 0 of −7 or less.
　上記のようなコバルトおよび水素をゼオライト上に担持させるためのイオン交換を行うに際して、上記のＺＳＭ－５（ＭＦＩ）型ゼオライトまたはモルデナイト（ＭＯＲ）型ゼオライトを担持したハニカム構造体を、硝酸アンモニウム（ＮＨ４ＮＯ３）の水溶液に入れ、温度７０～９０℃で、２～２４時間浸漬した後、洗浄する。ついで、洗浄物を、温度１００～１２０℃で、１～４時間乾燥し、ＮＨ４－ＭＦＩゼオライトまたはＮＨ４－ＭＯＲゼオライトを得る。 When performing ion exchange for supporting cobalt and hydrogen on zeolite as described above, a honeycomb structure supporting the above ZSM-5 (MFI) type zeolite or mordenite (MOR) type zeolite was converted to ammonium nitrate (NH 4 It is placed in an aqueous solution of NO 3 ), immersed at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then washed. Subsequently, the washed product is dried at a temperature of 100 to 120 ° C. for 1 to 4 hours to obtain NH 4 -MFI zeolite or NH 4 -MOR zeolite.
　その後、ＮＨ４－ＭＦＩゼオライトまたはＮＨ４－ＭＯＲゼオライトを、例えば硝酸コバルト［Ｃｏ（ＮＯ３）２］、酢酸コバルト［Ｃｏ（Ｃ２Ｈ３Ｏ２）２］、塩化コバルト［ＣｏＣｌ２］、蟻酸コバルト［ＣｏＣ４Ｈ１４Ｏ８）］等のコバルト化合物の水溶液に入れて、温度７０～９０℃で、２～２４時間浸漬した後、洗浄する。ついで、洗浄物を、温度１００～１２０℃で、１～４時間乾燥し、さらに温度４５０～５５０℃で、３～５時間焼成することにより、Ｃｏ／Ｈ－ＭＦＩゼオライトまたはＣｏ／Ｈ－ＭＯＲゼオライトを生成し、本発明の脱硝触媒を担持したハニカム構造体、すなわちハニカム型脱硝触媒が得られる。本発明による脱硝触媒のＣｏ担持量は、１～４重量％であることが好ましい。 Thereafter, NH 4 -MFI zeolite or NH 4 -MOR zeolite is converted into, for example, cobalt nitrate [Co (NO 3 ) 2 ], cobalt acetate [Co (C 2 H 3 O 2 ) 2 ], cobalt chloride [CoCl 2 ], formic acid. It is placed in an aqueous solution of a cobalt compound such as cobalt [CoC 4 H 14 O 8 ), immersed at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then washed. Next, the washed product is dried at a temperature of 100 to 120 ° C. for 1 to 4 hours, and further calcined at a temperature of 450 to 550 ° C. for 3 to 5 hours, whereby a Co / H-MFI zeolite or a Co / H-MOR zeolite is obtained. And a honeycomb structure carrying the denitration catalyst of the present invention, that is, a honeycomb type denitration catalyst is obtained. The amount of Co supported by the denitration catalyst according to the present invention is preferably 1 to 4% by weight.
　なおここで、前述のように、ガラスペーパーに、ナトリウム型ゼオライトと水とシリカゾルとからなるスラリーを塗布する工程を実施して、ハニカム構造体を作製するための基材を作製し、つぎに、このナトリウム型ゼオライト担持基材を波形に加工して波板状基材を得る工程と、上記の基材を平板に加工して平板状基材を得る工程と、該波板状基材に対しコバルトおよび水素をイオン交換させて波板状触媒を得る工程と、該平板状基材に対しコバルトおよび水素をイオン交換させて平板状触媒を得る工程と、該波板状触媒と該平板状触媒を交互に積層する工程を実施して、ハニカム型脱硝触媒を作製するようにしてもよい。 Here, as described above, a step of applying a slurry made of sodium-type zeolite, water, and silica sol to glass paper is carried out to produce a substrate for producing a honeycomb structure, Processing the sodium-type zeolite-supporting base material into a corrugated shape to obtain a corrugated base material, processing the base material into a flat plate to obtain a flat base material, and the corrugated base material. A step of obtaining a corrugated catalyst by ion exchange of cobalt and hydrogen, a step of obtaining a flat catalyst by ion exchange of cobalt and hydrogen with respect to the flat substrate, the corrugated catalyst and the flat catalyst A honeycomb type denitration catalyst may be manufactured by alternately stacking layers.
　さらに、本発明においては、－７以下のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトにコバルトおよびアルカリ金属またはアルカリ土類金属を担持させることによりハニカム型脱硝触媒を得ることができる。 Furthermore, in the present invention, a honeycomb-type denitration catalyst can be obtained by supporting cobalt and an alkali metal or an alkaline earth metal on a sodium-type zeolite having an acid strength corresponding to a Hammett acidity function H 0 of −7 or less. it can.
　上記のようなコバルトおよびアルカリ金属またはアルカリ土類金属をゼオライト上に担持させるためのイオン交換を行うに際して、上記のＺＳＭ－５（ＭＦＩ）型ゼオライトまたはモルデナイト（ＭＯＲ）型ゼオライトを担持したハニカム構造体を、アルカリ金属またはアルカリ土類金属の水溶液に入れ、温度７０～９０℃で、２～２４時間浸漬した後、洗浄する。ついで、洗浄物を、温度１００～１２０℃で、１～４時間乾燥し、アルカリ金属またはアルカリ土類金属イオン交換のゼオライトを得た。 A honeycomb structure supporting the above ZSM-5 (MFI) type zeolite or mordenite (MOR) type zeolite when performing ion exchange for supporting cobalt and alkali metal or alkaline earth metal on zeolite as described above Is placed in an aqueous solution of an alkali metal or an alkaline earth metal, immersed at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then washed. The washed product was then dried at a temperature of 100 to 120 ° C. for 1 to 4 hours to obtain an alkali metal or alkaline earth metal ion exchange zeolite.
　ここで、アルカリ金属としては、カリウム（Ｋ）が挙げられ、アルカリ土類金属としては、カルシウム（Ｃａ）、ストロンチウム（Ｓｒ）、およびバリウム（Ｂａ）よりなる群の中から選ばれた少なくとも１種の金属が挙げられる。 Here, the alkali metal includes potassium (K), and the alkaline earth metal is at least one selected from the group consisting of calcium (Ca), strontium (Sr), and barium (Ba). These metals are mentioned.
　そして、ナトリウム型のゼオライトにアルカリ金属またはアルカリ土類金属を担持させるには、例えばアルカリ金属またはアルカリ土類金属の硝酸水溶液、酢酸水溶液、塩化水溶液、蟻酸水溶液等が利用できる。 In order to support an alkali metal or alkaline earth metal on sodium-type zeolite, for example, an aqueous solution of nitric acid, aqueous solution of acetic acid, aqueous solution of chloride, aqueous solution of formic acid or the like of an alkali metal or alkaline earth metal can be used.
　その後、アルカリ金属またはアルカリ土類金属イオン交換ゼオライトを、例えば硝酸コバルト［Ｃｏ（ＮＯ３）２］、酢酸コバルト［Ｃｏ（Ｃ２Ｈ３Ｏ２）２］、塩化コバルト［ＣｏＣｌ２］、蟻酸コバルト［ＣｏＣ４Ｈ１４Ｏ８）］等のコバルト化合物の水溶液に入れて、温度７０～９０℃で、２～２４時間浸漬した後、洗浄する。ついで、洗浄物を、温度１００～１２０℃で、１～４時間乾燥し、さらに温度４５０～５５０℃で、３～５時間焼成することにより、Ｃｏ／アルカリ金属またはアルカリ土類金属イオン交換ゼオライトを生成し、本発明の脱硝触媒を担持したハニカム構造体、すなわちハニカム型脱硝触媒が得られる。 Thereafter, an alkali metal or alkaline earth metal ion-exchanged zeolite is converted into, for example, cobalt nitrate [Co (NO 3 ) 2 ], cobalt acetate [Co (C 2 H 3 O 2 ) 2 ], cobalt chloride [CoCl 2 ], cobalt formate. It is placed in an aqueous solution of a cobalt compound such as [CoC 4 H 14 O 8 )], immersed at a temperature of 70 to 90 ° C. for 2 to 24 hours, and then washed. Next, the washed product is dried at a temperature of 100 to 120 ° C. for 1 to 4 hours, and further calcined at a temperature of 450 to 550 ° C. for 3 to 5 hours to obtain a Co / alkali metal or alkaline earth metal ion-exchanged zeolite. A honeycomb structure which is produced and carries the denitration catalyst of the present invention, that is, a honeycomb type denitration catalyst is obtained.
　本発明による脱硝触媒において、アルカリ金属またはアルカリ土類金属の担持量は、１～４重量％であることが好ましい。 In the denitration catalyst according to the present invention, the supported amount of alkali metal or alkaline earth metal is preferably 1 to 4% by weight.
　なおここで、前述のように、ガラスペーパーに、ナトリウム型ゼオライトと水とシリカゾルとからなるスラリーを塗布する工程を実施して、ハニカム構造体を作製するための基材を作製し、つぎに、このナトリウム型ゼオライト担持基材を波形に加工して波板状基材を得る工程と、上記の基材を平板に加工して平板状基材を得る工程と、該波板状基材に対しコバルトおよびアルカリ金属またはアルカリ土類金属をイオン交換させて波板状触媒を得る工程と、該平板状基材に対しコバルトおよびアルカリ金属またはアルカリ土類金属をイオン交換させて平板状触媒を得る工程と、該波板状触媒と該平板状触媒を交互に積層する工程を実施して、ハニカム型脱硝触媒を作製するようにしてもよい。 Here, as described above, a step of applying a slurry made of sodium-type zeolite, water, and silica sol to glass paper is carried out to produce a substrate for producing a honeycomb structure, Processing the sodium-type zeolite-supporting base material into a corrugated shape to obtain a corrugated base material, processing the base material into a flat plate to obtain a flat base material, and the corrugated base material. A step of obtaining a corrugated plate catalyst by ion exchange of cobalt and alkali metal or alkaline earth metal, and a step of obtaining a flat plate catalyst by ion exchange of cobalt and alkali metal or alkaline earth metal with respect to the flat substrate. And a step of alternately laminating the corrugated catalyst and the flat catalyst may be carried out to produce a honeycomb type denitration catalyst.
　本発明の燃焼排ガスの浄化方法によれば、高濃度の窒素酸化物（ＮＯｘ）および硫黄酸化物（ＳＯｘ）が存在し、しかも排ガス温度が３００℃以下と低い、例えば船舶用機関すなわち船舶用大型ディーゼルエンジン、工場や発電所、地域冷暖房などの大規模ボイラー等から排出される燃焼排ガスから、窒素酸化物を効果的に低減することができるものである。 According to the method for purifying combustion exhaust gas of the present invention, high concentrations of nitrogen oxides (NOx) and sulfur oxides (SOx) are present, and the exhaust gas temperature is as low as 300 ° C. or less, for example, marine engines, ie large marine vessels. Nitrogen oxides can be effectively reduced from combustion exhaust gas discharged from diesel engines, factories, power plants, large-scale boilers such as district heating and cooling.
  つぎに、本発明の実施例を比較例と共に説明するが、本発明は、これらの実施例に限定されるものではない。
（実施例１）
　本発明の燃焼排ガスの浄化方法に使用する脱硝触媒として、－７のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトであるＺＳＭ－５（ＭＦＩ）型ゼオライトにコバルト（Ｃｏ）を担持させた触媒を製造した。 Next, examples of the present invention will be described together with comparative examples, but the present invention is not limited to these examples.
Example 1
As a denitration catalyst used in the method for purifying combustion exhaust gas of the present invention, cobalt (Co) is added to ZSM-5 (MFI) type zeolite, which is a sodium type zeolite having an acid strength corresponding to Hammett's acidity function H 0 of −7. A supported catalyst was produced.
　まず、市販のＺＳＭ－５（ＭＦＩ）型ゼオライト（商品名ミズカシーブスＥＸ１２２、水澤化学工業株式会社製：酸強度－７）１０ｇを、０．１モル（Ｍ）の硝酸コバルト［Ｃｏ（ＮＯ３）２］水溶液２００ｍｌに入れて、温度８０℃で、２４時間攪拌した後、濾過して洗浄し、ついで温度１１０℃で３時間乾燥し、さらに温度５００℃で４時間焼成することにより、コバルト（Ｃｏ）イオン交換ゼオライトを得た。この触媒のＣｏ担持量は、２．６重量％であり、ＺＳＭ－５（ＭＦＩ）型ゼオライトに対するコバルトイオンの交換率は、３２％であった。 First, 10 g of a commercially available ZSM-5 (MFI) type zeolite (trade name: Mizuka Sieves EX122, manufactured by Mizusawa Chemical Industry Co., Ltd .: acid strength -7) was added to 0.1 mol (M) of cobalt nitrate [Co (NO 3 ) 2 The solution was placed in 200 ml of an aqueous solution, stirred at a temperature of 80 ° C. for 24 hours, filtered, washed, dried at a temperature of 110 ° C. for 3 hours, and further calcined at a temperature of 500 ° C. for 4 hours to obtain cobalt (Co). An ion exchange zeolite was obtained. The amount of Co supported by this catalyst was 2.6% by weight, and the exchange rate of cobalt ions with respect to the ZSM-5 (MFI) type zeolite was 32%.
　本発明による脱硝触媒を用いて、本発明の燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を実施した。図１に脱硝触媒の性能評価試験装置のフロー図を示す。 Using the denitration catalyst of the present invention, a denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method of the present invention was conducted. FIG. 1 shows a flow chart of a denitration catalyst performance evaluation test apparatus.
　まず、上記のようにして得られたＣｏ／ＺＳＭ－５（ＭＦＩ）型ゼオライトよりなる触媒をプレス成形後に粉砕し、メッシュサイズ２８から１４に整粒して、図１にフロー図を示す試験装置において、内径１０．６ｍｍのステンレス製反応管よりなる脱硝反応器に、触媒の粉粒物を充填し、還元剤としてイソプロピルアルコール（ＩＰＡ）を濃度２００ｐｐｍで用いて、ＮＯ濃度が２００ｐｐｍの排ガスについて、下記の表１に示す試験条件で、評価試験を行った。 First, the catalyst comprising the Co / ZSM-5 (MFI) type zeolite obtained as described above was pulverized after press molding, and sized to a mesh size of 28 to 14, and the test apparatus shown in the flow chart of FIG. In, a denitration reactor comprising a stainless steel reaction tube having an inner diameter of 10.6 mm is filled with catalyst particles, isopropyl alcohol (IPA) is used as a reducing agent at a concentration of 200 ppm, and exhaust gas having a NO concentration of 200 ppm is used. An evaluation test was performed under the test conditions shown in Table 1 below.
Figure JPOXMLDOC01-appb-T000001
 　なお、反応器出口のガス分析は、窒素酸化物（ＮＯｘ）計を用いて、出口ＮＯｘ濃度を測定した。ＮＯｘ計での測定値から、下記の数式（１）によって触媒のＮＯｘ除去性能である脱硝率を算出した。
Figure JPOXMLDOC01-appb-T000001
 In addition, the gas analysis of the reactor exit measured the exit NOx density | concentration using the nitrogen oxide (NOx) meter. From the measured value with the NOx meter, the NOx removal rate, which is the NOx removal performance of the catalyst, was calculated by the following formula (1).
　脱硝率（％）＝（ＮＯｘｉｎ－ＮＯｘｏｕｔ）／ＮＯｘｉｎ×１００　　…（１）
　得られた脱硝触媒性能の評価試験の結果を、下記の表２に示した。
（実施例２～５）
　上記実施例１の場合と同様にして、本発明の燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を、上記表１に示す試験条件で実施するが、上記実施例１の場合と異なる点は、実施例２では、ＮＯ濃度が１０００ｐｐｍの排ガスについて、還元剤としてイソプロピルアルコール（ＩＰＡ）を濃度７００ｐｐｍで用いた点、実施例３では、ＮＯ濃度が２００ｐｐｍの排ガスは同じであるが、還元剤としてエタノールを濃度２００ｐｐｍで用いた点、実施例４では、ＮＯ濃度が１０００ｐｐｍの排ガスについて、還元剤としてエタノールを濃度７００ｐｐｍで用いた点、実施例５では、ＮＯ濃度が１０００ｐｐｍの排ガスについて、還元剤としてメタノールを濃度４０００ｐｐｍで用いた点にある。得られた脱硝触媒性能の評価試験の結果を、下記の表２にあわせて示した。
（実施例６～７）
　上記実施例１の場合と同様にして、本発明の燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を、上記表１に示す試験条件で実施するが、上記実施例１の場合と異なる点は、本発明の脱硝触媒として、－９のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトであるモルデナイト（ＭＯＲ）型ゼオライトにコバルト（Ｃｏ）を担持させた触媒を用いた点、および還元剤としてエタノールを用いた点にある。 Denitration rate (%) = (NOx in −NOx out ) / NOx in × 100 (1)
The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 2 below.
(Examples 2 to 5)
As in the case of Example 1, the denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method of the present invention is performed under the test conditions shown in Table 1 above, but differs from the case of Example 1 above. In Example 2, the exhaust gas having a NO concentration of 1000 ppm was the same as the exhaust gas having a NO concentration of 200 ppm in Example 3, except that isopropyl alcohol (IPA) was used as the reducing agent at a concentration of 700 ppm. In Example 4, ethanol was used at a concentration of 200 ppm. In Example 4, the NO concentration was 1000 ppm for the exhaust gas. As a reducing agent, ethanol was used at a concentration of 700 ppm. In Example 5, the NO concentration was 1000 ppm for the exhaust gas. As a result, methanol is used at a concentration of 4000 ppm. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 2 below.
(Examples 6 to 7)
As in the case of Example 1, the denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method of the present invention is performed under the test conditions shown in Table 1 above, but differs from the case of Example 1 above. Is a catalyst in which cobalt (Co) is supported on mordenite (MOR) type zeolite, which is a sodium type zeolite having an acid strength corresponding to Hammett acidity function H 0 of −9, as the denitration catalyst of the present invention. And ethanol as a reducing agent.
　まず、市販のモルデナイト（ＭＯＲ）型ゼオライト（商品名ＨＭ－２０、東ソー株式会社製：酸強度－９）１０ｇを、０．１ＭのＣｏ（ＮＯ３）２水溶液２００ｍｌに入れて、温度８０℃、２４時間攪拌した後、濾過して洗浄し、ついで温度１１０℃で３時間乾燥し、さらに温度５００℃で４時間焼成することにより、コバルト（Ｃｏ）イオン交換ゼオライトを得た。この触媒のＣｏ担持量は、２．０９重量％であり、モルデナイト（ＭＯＲ）型ゼオライトに対するコバルトイオンの交換率は、１７％であった。 First, 10 g of a commercially available mordenite (MOR) type zeolite (trade name HM-20, manufactured by Tosoh Corporation: acid strength -9) was placed in 200 ml of 0.1 M Co (NO 3 ) 2 aqueous solution, and the temperature was 80 ° C. The mixture was stirred for 24 hours, filtered and washed, then dried at a temperature of 110 ° C. for 3 hours, and further calcined at a temperature of 500 ° C. for 4 hours to obtain a cobalt (Co) ion-exchanged zeolite. The amount of Co supported by this catalyst was 2.09% by weight, and the exchange rate of cobalt ions with respect to mordenite (MOR) type zeolite was 17%.
　そして、実施例６では、得られた本発明によるＣｏ／モルデナイト（ＭＯＲ）型ゼオライトよりなる脱硝触媒を用いて、ＮＯ濃度が２００ｐｐｍの排ガスについて、還元剤としてエタノールを濃度２００ｐｐｍで使用し、実施例７では、同脱硝触媒を用いて、ＮＯ濃度が１０００ｐｐｍの排ガスについて、還元剤としてエタノールを濃度７００ｐｐｍで使用して、本発明の燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を実施した。得られた脱硝触媒性能の評価試験の結果を、下記の表２にあわせて示した。
（比較例１～２）
　比較のために、上記実施例１の場合と同様にして、燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を実施するが、上記実施例１の場合と異なる点は、脱硝触媒として、－５のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトであるＢＥＡ型ゼオライトにコバルト（Ｃｏ）を担持させた触媒を使用した点、および還元剤としてエタノールを用いた点にある。 In Example 6, using the obtained denitration catalyst made of Co / mordenite (MOR) type zeolite according to the present invention, NOx concentration was 200 ppm, and ethanol was used as a reducing agent at a concentration of 200 ppm. In No. 7, a denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method of the present invention was carried out using the same denitration catalyst and using ethanol as a reducing agent at a concentration of 700 ppm for exhaust gas having a NO concentration of 1000 ppm. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 2 below.
(Comparative Examples 1 and 2)
For comparison, a denitration catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas is performed in the same manner as in the case of the above Example 1. The difference from the case of Example 1 is that This is in that a catalyst in which cobalt (Co) is supported on BEA type zeolite, which is a sodium type zeolite having an acid strength corresponding to Hammett's acidity function H 0 of 5, is used, and ethanol is used as a reducing agent.
　まず、市販のＢＥＡ型ゼオライト（商品名Ｈ－ＢＥＡ－３５、ズードケミー触媒株式会社製：酸強度－５）１０ｇを、０．１ＭのＣｏ（ＮＯ３）２水溶液２００ｍｌに入れて、温度８０℃、２４時間攪拌した後、濾過して洗浄し、ついで温度１１０℃で３時間乾燥し、さらに温度５００℃で４時間焼成することにより、コバルト（Ｃｏ）イオン交換ゼオライトを得た。この触媒のＣｏ担持量は、１．９２重量％であり、ＢＥＡ型ゼオライトに対するコバルトイオンの交換率は、２６％であった。 First, 10 g of commercially available BEA type zeolite (trade name H-BEA-35, manufactured by Zude Chemie Catalysts Co., Ltd .: acid strength -5) was placed in 200 ml of 0.1 M Co (NO 3 ) 2 aqueous solution, and the temperature was 80 ° C. The mixture was stirred for 24 hours, filtered and washed, then dried at a temperature of 110 ° C. for 3 hours, and further calcined at a temperature of 500 ° C. for 4 hours to obtain a cobalt (Co) ion-exchanged zeolite. The amount of Co supported by this catalyst was 1.92% by weight, and the exchange rate of cobalt ions with respect to the BEA type zeolite was 26%.
　そして、比較例１では、上記のようにして得られたＣｏ／ＢＥＡ型ゼオライトよりなる脱硝触媒を用いて、ＮＯ濃度が２００ｐｐｍの排ガスについて、還元剤としてエタノールを濃度２００ｐｐｍで使用し、比較例２では、同脱硝触媒を用いて、ＮＯ濃度が１０００ｐｐｍの排ガスについて、還元剤としてエタノールを濃度７００ｐｐｍで使用して、燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を実施した。得られた脱硝触媒性能の評価試験の結果を、下記の表２にあわせて示した。
（比較例３～４）
　比較のために、上記実施例１の場合と同様にして、燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を実施するが、上記実施例１の場合と異なる点は、燃焼排ガスの浄化方法に使用する脱硝触媒として、－３のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトであるＹ型ゼオライトにコバルト（Ｃｏ）を担持させた触媒を使用した点、および還元剤としてエタノールを用いた点にある。 And in the comparative example 1, using the denitration catalyst which consists of the Co / BEA type zeolite obtained as mentioned above, ethanol was used as a reducing agent at a concentration of 200 ppm with respect to the exhaust gas having a NO concentration of 200 ppm. Then, the NOx removal catalyst performance evaluation test corresponding to the purification method of combustion exhaust gas was implemented using the same denitration catalyst and using ethanol as the reducing agent at a concentration of 700 ppm for the exhaust gas having a NO concentration of 1000 ppm. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 2 below.
(Comparative Examples 3 to 4)
For comparison, a denitration catalyst performance evaluation test corresponding to a method for purifying combustion exhaust gas is performed in the same manner as in the case of Example 1. The difference from the case of Example 1 is that the method for purifying combustion exhaust gas As a denitration catalyst used in the present invention, a catalyst in which cobalt (Co) is supported on a Y-type zeolite, which is a sodium-type zeolite having an acid strength corresponding to a Hammett acidity function H 0 of −3, and a reducing agent are used. The point is that ethanol was used.
　まず、市販のＹ型ゼオライト（商品名ミズカシーブスＹ－４２０、水澤化学工業株式会社製：酸強度－３）１０ｇを、０．１ＭのＣｏ（ＮＯ３）２水溶液２００ｍｌに入れて、温度８０℃、２４時間攪拌した後、濾過して洗浄し、ついで温度１１０℃で３時間乾燥し、さらに温度５００℃で４時間焼成することにより、コバルト（Ｃｏ）イオン交換ゼオライトを得た。この触媒のＣｏ担持量は、１０．３３重量％であり、Ｙ型ゼオライトに対するコバルトイオンの交換率は、２２％であった。 First, 10 g of a commercially available Y-type zeolite (trade name: Mizuka Sieves Y-420, manufactured by Mizusawa Chemical Industry Co., Ltd .: acid strength-3) was placed in 200 ml of a 0.1 M Co (NO 3 ) 2 aqueous solution at a temperature of 80 ° C. The mixture was stirred for 24 hours, filtered and washed, then dried at a temperature of 110 ° C. for 3 hours, and further calcined at a temperature of 500 ° C. for 4 hours to obtain a cobalt (Co) ion-exchanged zeolite. The amount of Co supported by this catalyst was 10.33% by weight, and the exchange rate of cobalt ions with respect to the Y-type zeolite was 22%.
　そして、比較例３では、上記のようにして得られたＣｏ／Ｙ型ゼオライトよりなる脱硝触媒を用いて、ＮＯ濃度が２００ｐｐｍの排ガスについて、還元剤としてエタノールを濃度２００ｐｐｍで使用し、比較例４では、同脱硝触媒を用いて、ＮＯ濃度が１０００ｐｐｍの排ガスについて、還元剤としてエタノールを濃度７００ｐｐｍで使用して、燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を実施した。得られた脱硝触媒性能の評価試験の結果を、下記の表２にあわせて示した。 And in the comparative example 3, using the denitration catalyst which consists of a Co / Y type zeolite obtained as mentioned above, about the exhaust gas whose NO concentration is 200 ppm, ethanol is used as a reducing agent at a concentration of 200 ppm. Then, the NOx removal catalyst performance evaluation test corresponding to the purification method of combustion exhaust gas was implemented using the same denitration catalyst and using ethanol as the reducing agent at a concentration of 700 ppm for the exhaust gas having a NO concentration of 1000 ppm. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 2 below.
Figure JPOXMLDOC01-appb-T000002
 　上記表２の結果から明らかなように、本発明による実施例１～７の脱硝試験においては、比較例１～４の脱硝試験の場合より、いずれも高い脱硝率を示しており、本発明による脱硝触媒が、反応温度２５０℃で高い触媒性能を有することが分かる。
Figure JPOXMLDOC01-appb-T000002
 As is clear from the results in Table 2 above, the denitration tests of Examples 1 to 7 according to the present invention all showed a higher denitration rate than the denitration tests of Comparative Examples 1 to 4, and according to the present invention. It can be seen that the denitration catalyst has high catalytic performance at a reaction temperature of 250 ° C.
　ここで、脱硝性能を示す量として、脱硝反応がＮＯｘの１次反応であると仮定した場合の反応速度定数Ｋを指標とした。すなわち、Ｋは下記の式で表される。そして、上記の本発明による実施例１～７の脱硝試験、および比較例１～４の脱硝試験において、反応速度定数Ｋを下記の式から算出し、得られた反応速度定数Ｋの結果を、下記の表３に示した。 Here, as an amount indicating the denitration performance, a reaction rate constant K when the denitration reaction is assumed to be a primary reaction of NOx was used as an index. That is, K is represented by the following formula. Then, in the denitration tests of Examples 1 to 7 and the denitration tests of Comparative Examples 1 to 4 according to the present invention, the reaction rate constant K was calculated from the following formula, and the obtained reaction rate constant K was The results are shown in Table 3 below.
　　Ｋ＝－Ｉｎ（１－ｘ）×ＳＶ
　Ｋ：反応速度定数
　Ｘ：反応率（脱硝率）
　ＳＶ：空間速度（ｌ／ｈ） K = -In (1-x) × SV
K: Reaction rate constant X: Reaction rate (denitration rate)
SV: Space velocity (l / h)
Figure JPOXMLDOC01-appb-T000003
 　上記表３の結果から明らかなように、本発明による実施例１～７の脱硝試験においては、比較例１～４の脱硝試験の場合より、いずれも反応速度定数Ｋが高く、窒素酸化物（ＮＯｘ）を効率良く低減させていることが分かる。
（実施例８と９）
　つぎに、本発明による脱硝触媒について、三酸化硫黄（ＳＯ３）に対する耐性をテストした。
Figure JPOXMLDOC01-appb-T000003
 As is clear from the results of Table 3 above, in the denitration tests of Examples 1 to 7 according to the present invention, the reaction rate constant K was higher in all cases than in the denitration tests of Comparative Examples 1 to 4, and nitrogen oxides ( It can be seen that NOx) is efficiently reduced.
(Examples 8 and 9)
Next, the denitration catalyst according to the present invention was tested for resistance to sulfur trioxide (SO 3 ).
　表４に示す条件で一定時間ＳＯ３を含むガスに実施例触媒をさらすＳＯ３耐性試験を実施し、本発明による脱硝触媒の硫黄酸化物に対する耐性をテストした。 An SO 3 resistance test in which the catalyst of the example was exposed to a gas containing SO 3 for a certain period of time under the conditions shown in Table 4 was conducted to test the resistance of the denitration catalyst according to the present invention to sulfur oxides.
　まず、市販のナトリウム型ゼオライトであるＺＳＭ－５（ＭＦＩ）型ゼオライト（商品名ミズカシーブスＥＸ１２２、水澤化学工業株式会社製：酸強度－７）１０ｇを、０．１モル（Ｍ）の硝酸コバルト［Ｃｏ（ＮＯ３）２］水溶液５００ｍｌに入れて、温度８０℃で、２４時間攪拌した後、濾過して洗浄し、ついで温度１１０℃で３時間乾燥し、さらに温度５００℃で４時間焼成することにより、コバルト（Ｃｏ）イオン交換ゼオライトを得た。この触媒のＣｏ担持量は、２．６重量％であり、ＺＳＭ－５（ＭＦＩ）型ゼオライトに対するコバルトイオンの交換率は、３２％であった。 First, 10 g of ZSM-5 (MFI) type zeolite (trade name: Mizuka Sieves EX122, manufactured by Mizusawa Chemical Industry Co., Ltd .: acid strength -7), which is a commercially available sodium type zeolite, was added to 0.1 mol (M) of cobalt nitrate [Co (NO 3 ) 2 ] By placing in 500 ml of aqueous solution, stirring at a temperature of 80 ° C. for 24 hours, filtering and washing, then drying at a temperature of 110 ° C. for 3 hours, and further baking at a temperature of 500 ° C. for 4 hours. Cobalt (Co) ion exchange zeolite was obtained. The amount of Co supported by this catalyst was 2.6% by weight, and the exchange rate of cobalt ions with respect to the ZSM-5 (MFI) type zeolite was 32%.
　つぎに、本発明の実施例８において、このＣｏ／ＺＳＭ－５（ＭＦＩ）型ゼオライトを、下記の表４に示す条件で、三酸化硫黄（ＳＯ３）を含むガスに２０時間さらした。なお、ＳＯ３は、定量送液ポンプを用いて蒸発管に送り、蒸発器内でガス化してから、反応管に流入した。 Next, in Example 8 of the present invention, this Co / ZSM-5 (MFI) type zeolite was exposed to a gas containing sulfur trioxide (SO 3 ) for 20 hours under the conditions shown in Table 4 below. In addition, SO 3 was sent to the evaporation pipe using a fixed liquid feed pump, gasified in the evaporator, and then flowed into the reaction pipe.
　そして、このＳＯ３を含むガスにさらした本発明の脱硝触媒を用いて、上記実施例４の場合と同様に、ＮＯ濃度が１０００ｐｐｍの排ガスについて、還元剤としてエタノールを濃度７００ｐｐｍで使用して、燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を実施し、得られた脱硝触媒性能の評価試験の結果を、下記の表５に示した。 Then, using the denitration catalyst of the present invention exposed to the gas containing SO 3 , as in the case of Example 4, the exhaust gas having a NO concentration of 1000 ppm was used with ethanol as a reducing agent at a concentration of 700 ppm. Table 5 below shows the results of the denitration catalyst performance evaluation test corresponding to the purification method of combustion exhaust gas, and the obtained denitration catalyst performance evaluation test.
　また、本発明の実施例９においては、上記Ｃｏ／ＺＳＭ－５（ＭＦＩ）型ゼオライトを、下記の表４に示す条件で、三酸化硫黄（ＳＯ３）を含むガスに３６時間さらした後の脱硝触媒を用いて、実施例８の場合と同様に、脱硝触媒性能評価試験を実施し、得られた脱硝触媒性能の評価試験の結果を、下記の表５にあわせて示した。 In Example 9 of the present invention, the Co / ZSM-5 (MFI) type zeolite was exposed to a gas containing sulfur trioxide (SO 3 ) for 36 hours under the conditions shown in Table 4 below. Using the denitration catalyst, a denitration catalyst performance evaluation test was conducted in the same manner as in Example 8, and the results of the obtained denitration catalyst performance evaluation test are shown in Table 5 below.
　なお、下記の表５には、参考として、三酸化硫黄（ＳＯ３）を含むガスにさらしていないＣｏ／ＺＳＭ－５（ＭＦＩ）型ゼオライトよりなる脱硝触媒を用いた実施例４の脱硝触媒性能の評価試験の結果を、あわせて示した。 In Table 5, the denitration catalyst performance of Example 4 using a denitration catalyst made of Co / ZSM-5 (MFI) type zeolite not exposed to a gas containing sulfur trioxide (SO 3 ) is shown as a reference. The results of the evaluation test were also shown.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
 　上記表５の実施例８と９の結果から明らかなように、本発明による脱硝触媒が、船舶用機関から排出される排ガスに多く含まれる硫黄酸化物（ＳＯｘ）の耐性にも優れていることが分かる。
（実施例１０）
　本発明の燃焼排ガスの浄化方法に使用する脱硝触媒として、－７のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトであるＺＳＭ－５（ＭＦＩ）型ゼオライトにコバルト（Ｃｏ）および水素（Ｈ）を担持させた触媒を製造した。
Figure JPOXMLDOC01-appb-T000005
 As is clear from the results of Examples 8 and 9 in Table 5 above, the denitration catalyst according to the present invention has excellent resistance to sulfur oxide (SOx) contained in a large amount of exhaust gas discharged from marine engines. I understand.
(Example 10)
As a denitration catalyst used in the method for purifying combustion exhaust gas of the present invention, ZSM-5 (MFI) type zeolite, which is a sodium type zeolite having acid strength corresponding to Hammett's acidity function H 0 of −7, cobalt (Co) and A catalyst carrying hydrogen (H) was produced.
　まず、市販のＺＳＭ－５（ＭＦＩ）ゼオライト（商品名ミズカシ－ブスＥＸ１２２、水澤化学工業株式会社製：酸強度－７）１０ｇを、０．１モル（Ｍ）の硝酸アンモニウム［ＮＨ４ＮＯ３］水溶液２００ｍｌに入れて、温度８０℃で、２４時間攪拌した後、濾過して洗浄した。ついで濾過洗浄物を温度１１０℃で、３時間乾燥し、ＮＨ４－ＭＦＩゼオライトを得た。さらにＮＨ４－ＭＦＩゼオライトを、０．１モル（Ｍ）の硝酸コバルト［Ｃｏ（ＮＯ３）２］水溶液２００ｍｌに入れ、温度８０℃で、２４時間攪拌した後、濾過して洗浄した。ついで濾過洗浄物を、温度１１０℃で、３時間乾燥し、さらに温度５００℃で、４時間焼成することにより、本発明の水素（Ｈ）／コバルト（Ｃｏ）イオン交換ＺＳＭ－５（ＭＦＩ）ゼオライトを得た。この触媒のＣｏ担持量は１．４６重量％であった。 First, 10 g of a commercially available ZSM-5 (MFI) zeolite (trade name Mizukashi-bus EX122, manufactured by Mizusawa Chemical Industry Co., Ltd .: acid strength -7) was added in an amount of 0.1 mol (M) of ammonium nitrate [NH 4 NO 3 ] in water. The solution was placed in 200 ml, stirred at a temperature of 80 ° C. for 24 hours, filtered and washed. Subsequently, the filtered washing was dried at 110 ° C. for 3 hours to obtain NH 4 -MFI zeolite. Further, NH 4 -MFI zeolite was put into 200 ml of 0.1 mol (M) cobalt nitrate [Co (NO 3 ) 2 ] aqueous solution, stirred at a temperature of 80 ° C. for 24 hours, and then washed by filtration. Next, the filtered and washed product is dried at 110 ° C. for 3 hours, and further calcined at 500 ° C. for 4 hours, whereby the hydrogen (H) / cobalt (Co) ion exchange ZSM-5 (MFI) zeolite of the present invention is obtained. Got. The amount of Co supported by this catalyst was 1.46% by weight.
　こうして製造した本発明による脱硝触媒を用いて、本発明の燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を、図１にフロ－図を示す脱硝触媒の性能評価試験装置により実施した。 Using the thus produced denitration catalyst according to the present invention, a denitration catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas of the present invention was carried out using a denitration catalyst performance evaluation test apparatus shown in the flow chart of FIG.
　まず、上記のようにして得られたＨ／Ｃｏ－ＺＳＭ－５（ＭＦＩ）型ゼオライトよりなる触媒をプレス成形後に粉砕し、メッシュサイズ２８から１４に整粒して、脱硝触媒の粉粒物を調製した。ついで、図１にフロ－図を示す試験装置において、内径１０．６ｍｍのステンレス製反応管よりなる脱硝反応器に、脱硝触媒の粉粒物を充填し、還元剤としてエタノ－ルを濃度７００ｐｐｍで用いて、ＮＯ濃度が１０００ｐｐｍの排ガスについて、前記の表１に示す試験条件で、性能評価試験を行った。得られた脱硝触媒性能の評価試験の結果を、下記の表６に示した。
（実施例１１）
　上記実施例１０の場合と同様にして、本発明の燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を、前記表１に示す試験条件で実施するが、上記実施例１０の場合と異なる点は、還元剤にメタノールを濃度４０００ｐｐｍで用いた点にある。得られた脱硝触媒性能の評価試験の結果を、下記の表６にあわせて示した。なお、下記の表６には、比較のために、前述の比較例２と４の脱硝触媒性能の評価試験の結果をあわせて示した。 First, the catalyst made of H / Co-ZSM-5 (MFI) type zeolite obtained as described above is pulverized after press molding and sized to a mesh size of 28 to 14, and the denitration catalyst powder is obtained. Prepared. Next, in the test apparatus shown in the flow chart of FIG. 1, a denitration reactor composed of a stainless steel reaction tube having an inner diameter of 10.6 mm is filled with denitration catalyst powder, and ethanol as a reducing agent is added at a concentration of 700 ppm. Using the exhaust gas having a NO concentration of 1000 ppm, a performance evaluation test was performed under the test conditions shown in Table 1 above. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 6 below.
(Example 11)
As in the case of Example 10, the NOx removal catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas of the present invention is performed under the test conditions shown in Table 1, but is different from the case of Example 10 above. Is that methanol is used as a reducing agent at a concentration of 4000 ppm. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 6 below. Table 6 below also shows the results of the denitration catalyst performance evaluation test of Comparative Examples 2 and 4 described above for comparison.
Figure JPOXMLDOC01-appb-T000006
 　上記表６の結果から明らかなように、本発明による実施例１０および１１の脱硝試験においては、比較例２および４の脱硝試験に比べて、いずれも高い脱硝率を示しており、本発明による脱硝触媒が、反応温度２５０℃で高い触媒性能を有することが分かる。
Figure JPOXMLDOC01-appb-T000006
 As is clear from the results of Table 6 above, the denitration tests of Examples 10 and 11 according to the present invention all showed a higher denitration rate than the denitration tests of Comparative Examples 2 and 4, and according to the present invention. It can be seen that the denitration catalyst has high catalytic performance at a reaction temperature of 250 ° C.
　ここで、脱硝性能を示す量として、上記の本発明による実施例１０および１１の脱硝試験における反応速度定数Ｋを算出し、得られた反応速度定数Ｋの結果を、下記の表７に示した。なお、下記の表７には、比較のために、前述の比較例２および４の脱硝試験における反応速度定数Ｋの結果をあわせて示した。 Here, as an amount indicating the denitration performance, the reaction rate constant K in the denitration test of Examples 10 and 11 according to the present invention was calculated, and the results of the obtained reaction rate constant K are shown in Table 7 below. . Table 7 below also shows the results of the reaction rate constant K in the denitration test of Comparative Examples 2 and 4 described above for comparison.
Figure JPOXMLDOC01-appb-T000007
 　上記表７の結果から明らかなように、本発明による実施例１０および１１の脱硝試験においては、比較例２および４の脱硝試験の場合より、いずれも反応速度定数Ｋが高く、窒素酸化物（ＮＯｘ）を効率良く低減させていることが分かる。
（実施例１２）
　つぎに、脱硝触媒が、高濃度の硫黄酸化物（ＳＯｘ）の存在下においても、窒素酸化物を効果的に低減できることを確認するために、本発明による脱硝触媒について、三酸化硫黄（ＳＯ３）に対する耐性をテストした。
Figure JPOXMLDOC01-appb-T000007
 As is clear from the results in Table 7 above, in the denitration tests of Examples 10 and 11 according to the present invention, both of the reaction rate constants K were higher than in the denitration tests of Comparative Examples 2 and 4, and nitrogen oxides ( It can be seen that NOx) is efficiently reduced.
Example 12
Next, in order to confirm that the denitration catalyst can effectively reduce nitrogen oxides even in the presence of a high concentration of sulfur oxide (SOx), the denitration catalyst according to the present invention is treated with sulfur trioxide (SO 3). ).
　前記の表４に示す条件で、一定時間、三酸化硫黄（ＳＯ３）を含むガスに脱硝触媒をさらす耐性試験を実施し、本発明による脱硝触媒の硫黄酸化物（ＳＯｘ）に対する耐性をテストした。 Under the conditions shown in Table 4 above, a resistance test in which the denitration catalyst was exposed to a gas containing sulfur trioxide (SO 3 ) for a certain period of time was performed, and the resistance of the denitration catalyst according to the present invention to sulfur oxide (SOx) was tested. .
　実施例１２では、本発明による実施例１０において製造したＨ／Ｃｏ－ＺＳＭ－５（ＭＦＩ）型ゼオライトを、脱硝触媒性能評価試験を実施する前に、三酸化硫黄（ＳＯ３）を含むガスに４７時間さらした。なお、三酸化硫黄（ＳＯ３）は、定量送液ポンプを用いて蒸発管に送り、蒸発器内でガス化してから、反応管に流入した。 In Example 12, the H / Co-ZSM-5 (MFI) type zeolite produced in Example 10 according to the present invention was converted to a gas containing sulfur trioxide (SO 3 ) before performing the denitration catalyst performance evaluation test. It was exposed for 47 hours. In addition, sulfur trioxide (SO 3 ) was sent to the evaporation pipe using a fixed liquid feed pump, gasified in the evaporator, and then flowed into the reaction pipe.
　ついで、この三酸化硫黄さらし後の脱硝触媒を用いて、上記実施例１０の場合と同様に、燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を実施した。得られた脱硝触媒性能の評価試験の結果を、下記の表８に示した。
（実施例１３）
　上記実施例１０の場合と同様にして、本発明による脱硝触媒について、三酸化硫黄（ＳＯ３）に対する耐性をテストするが、上記実施例１０の場合と異なる点は、実施例１１では、本発明による実施例１０において製造したＨ／Ｃｏ－ＺＳＭ－５（ＭＦＩ）型ゼオライトを、脱硝触媒性能評価試験を実施する前に、三酸化硫黄（ＳＯ３）を含むガスに１１０時間さらした点にある。 Next, using this denitration catalyst after exposure to sulfur trioxide, a denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method was conducted in the same manner as in Example 10 above. The results of the evaluation test of the obtained denitration catalyst performance are shown in Table 8 below.
(Example 13)
In the same manner as in Example 10, the denitration catalyst according to the present invention was tested for resistance to sulfur trioxide (SO 3 ). The difference from Example 10 is that in Example 11, the present invention The H / Co-ZSM-5 (MFI) type zeolite produced in Example 10 according to the present invention was exposed to a gas containing sulfur trioxide (SO 3 ) for 110 hours before performing the denitration catalyst performance evaluation test. .
　ついで、この三酸化硫黄さらし後の脱硝触媒を用いて、上記実施例１０の場合と同様に、燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を実施した。得られた脱硝触媒性能の評価試験の結果を、下記の表８にあわせて示した。 Next, using this denitration catalyst after exposure to sulfur trioxide, a denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method was conducted in the same manner as in Example 10 above. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 8 below.
Figure JPOXMLDOC01-appb-T000008
 　上記表８の結果から明らかなように、本発明の実施例１２と１３の三酸化硫黄さらし後の脱硝触媒による脱硝試験においては、いずれも高い脱硝率を示しており、本発明による脱硝触媒は、例えば船舶用機関から排出される排ガスに多く含まれる硫黄酸化物（ＳＯｘ）の耐性にも優れていることが分かる。
（実施例１４）
　本発明の燃焼排ガスの浄化方法に使用する脱硝触媒として、－７のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトであるＺＳＭ－５（ＭＦＩ）ゼオライトに、コバルト（Ｃｏ）およびバリウム（Ｂａ）を担持させた触媒を製造した。
Figure JPOXMLDOC01-appb-T000008
 As is clear from the results in Table 8 above, in the denitration test using the denitration catalyst after exposure to sulfur trioxide in Examples 12 and 13 of the present invention, both showed a high denitration rate. For example, it turns out that it is excellent also in the tolerance of the sulfur oxide (SOx) contained abundantly in the exhaust gas discharged | emitted from the engine for ships.
(Example 14)
As a denitration catalyst used in the method for purifying combustion exhaust gas of the present invention, ZSM-5 (MFI) zeolite, which is a sodium type zeolite having an acid strength corresponding to Hammett's acidity function H 0 of −7, cobalt (Co) and A catalyst supporting barium (Ba) was produced.
　まず、市販のＺＳＭ－５（ＭＦＩ）ゼオライト（商品名ミズカシーブスＥＸ１２２、水澤化学工業株式会社製：酸強度－７）１０ｇを、０．１モル（Ｍ）の硝酸バリウム［Ｂａ（ＮＯ３）２］水溶液２００ｍｌに入れて、温度８０℃で、２４時間攪拌した後、濾過して洗浄した。ついで濾過洗浄物を、温度１１０℃で３時間乾燥した。つぎに乾燥物を、０．１モル（Ｍ）の硝酸コバルト［Ｃｏ（ＮＯ３）２］水溶液２００ｍｌに入れ、温度８０℃で、２４時間攪拌した後、濾過して洗浄した。ついで濾過洗浄物を、温度１１０℃で、３時間乾燥し、さらに温度５００℃で、４時間焼成することにより、本発明のコバルト（Ｃｏ）／バリウム（Ｂａ）イオン交換ＺＳＭ－５（ＭＦＩ）ゼオライトを得た。この触媒のコバルト（Ｃｏ）の担持量は１．０６重量％、バリウム（Ｂａ）の担持量は１．１２重量％であった。 First, 10 g of a commercially available ZSM-5 (MFI) zeolite (trade name: Mizuka Sieves EX122, manufactured by Mizusawa Chemical Industry Co., Ltd .: acid strength -7) was added to 0.1 mol (M) of barium nitrate [Ba (NO 3 ) 2 ]. The solution was placed in 200 ml of an aqueous solution, stirred at a temperature of 80 ° C. for 24 hours, and then washed by filtration. Subsequently, the filtered washing product was dried at a temperature of 110 ° C. for 3 hours. Next, the dried product was put into 200 ml of 0.1 mol (M) cobalt nitrate [Co (NO 3 ) 2 ] aqueous solution, stirred at a temperature of 80 ° C. for 24 hours, filtered and washed. The filtered and washed product is then dried at 110 ° C. for 3 hours and further calcined at 500 ° C. for 4 hours, whereby the cobalt (Co) / barium (Ba) ion-exchanged ZSM-5 (MFI) zeolite of the present invention. Got. The amount of cobalt (Co) supported on this catalyst was 1.06% by weight, and the amount of barium (Ba) supported was 1.12% by weight.
　こうして製造した本発明による脱硝触媒を用いて、本発明の燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を、図１にフロ－図を示す脱硝触媒の性能評価試験装置により実施した。 Using the thus produced denitration catalyst according to the present invention, a denitration catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas of the present invention was carried out using a denitration catalyst performance evaluation test apparatus shown in the flow chart of FIG.
　まず、上記のようにして得られたＣｏ／Ｂａ‐ＺＳＭ－５（ＭＦＩ）ゼオライトよりなる触媒をプレス成形後に粉砕し、メッシュサイズ２８から１４に整粒して、脱硝触媒の粉粒物を調製した。ついで、図１にフロー図を示す試験装置において、内径１０．６ｍｍのステンレス製反応管よりなる脱硝反応器に、脱硝触媒の粉粒物を充填し、還元剤としてエタノールを濃度２００ｐｐｍで用いて、ＮＯ濃度が２００ｐｐｍの排ガスについて、前記の表１に示す試験条件で、性能評価試験を行った。得られた脱硝触媒性能の評価試験の結果を、下記の表９に示した。
（実施例１５）
　上記実施例１４の場合と同様にして、本発明の燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を、前記表１に示す試験条件で実施するが、上記実施例１４の場合と異なる点は、実施例１５では、ＮＯ濃度が１０００ｐｐｍの排ガスについて、還元剤としてエタノールを濃度７００ｐｐｍで使用した点にある。得られた脱硝触媒性能の評価試験の結果を、下記の表９にあわせて示した。
（実施例１６）
　上記実施例１４の場合と同様にして、本発明の燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を、前記表１に示す試験条件で実施するが、上記実施例１４の場合と異なる点は、実施例１６では、ＮＯ濃度が１０００ｐｐｍの排ガスについて、還元剤にメタノールを４０００ｐｐｍ用いた点にある。得られた脱硝触媒性能の評価試験の結果を、下記の表９にあわせて示した。
（実施例１７）
　上記実施例１４の場合と同様にして、本発明の燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を、前記表１に示す試験条件で実施するが、上記実施例１４の場合と異なる点は、本発明の脱硝触媒として、－７のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトであるＺＳＭ－５（ＭＦＩ）ゼオライトにコバルト（Ｃｏ）およびカリウム（Ｋ）を担持させた触媒を用いた点にある。 First, the catalyst made of Co / Ba-ZSM-5 (MFI) zeolite obtained as described above is pulverized after press molding and sized to a mesh size of 28 to 14 to prepare a denitration catalyst powder. did. Next, in the test apparatus shown in the flow chart of FIG. 1, a denitration reactor composed of a stainless steel reaction tube having an inner diameter of 10.6 mm is filled with denitration catalyst powder, and ethanol is used as a reducing agent at a concentration of 200 ppm. A performance evaluation test was conducted on the exhaust gas having a NO concentration of 200 ppm under the test conditions shown in Table 1 above. The results of the evaluation test of the obtained denitration catalyst performance are shown in Table 9 below.
(Example 15)
In the same manner as in Example 14, the denitration catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas of the present invention is performed under the test conditions shown in Table 1 above, but differs from the case of Example 14 above. In Example 15, ethanol is used as a reducing agent at a concentration of 700 ppm for exhaust gas having a NO concentration of 1000 ppm. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 9 below.
(Example 16)
In the same manner as in Example 14, the denitration catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas of the present invention is performed under the test conditions shown in Table 1 above, but differs from the case of Example 14 above. Is that in Example 16, 4000 ppm of methanol was used as the reducing agent for the exhaust gas having a NO concentration of 1000 ppm. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 9 below.
(Example 17)
In the same manner as in Example 14, the denitration catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas of the present invention is performed under the test conditions shown in Table 1 above, but differs from the case of Example 14 above. As a denitration catalyst of the present invention, cobalt (Co) and potassium (K) are supported on ZSM-5 (MFI) zeolite, which is a sodium-type zeolite having an acid strength corresponding to Hammett's acidity function H 0 of −7. This is in the point of using a new catalyst.
　この脱硝触媒を、つぎのようにして製造した。まず、市販のＺＳＭ－５（ＭＦＩ）ゼオライト（商品名ミズカシーブスＥＸ１２２、水澤化学工業株式会社製：酸強度－７）１０ｇを、０．１モル（Ｍ）の硝酸カリウム［Ｋ（ＮＯ３）２］水溶液２００ｍｌに入れて、温度８０℃で、２４時間攪拌した後、濾過して洗浄した。ついで濾過洗浄物を、温度１１０℃で、３時間乾燥した。つぎに乾燥物を、０．１モル（Ｍ）の硝酸コバルト［Ｃｏ（ＮＯ３）２］水溶液２００ｍｌに入れ、温度８０℃で、２４時間攪拌した後、濾過して洗浄した。ついで濾過洗浄物を、温度１１０℃で、３時間乾燥し、さらに温度５００℃で、４時間焼成することにより、コバルト（Ｃｏ）／カリウム（Ｋ）イオン交換ＺＳＭ－５（ＭＦＩ）ゼオライトを得た。この触媒のコバルト（Ｃｏ）担持量は２．２４重量％、カリウム（Ｋ）担持量は１．３重量％であった。 This denitration catalyst was produced as follows. First, 10 g of a commercially available ZSM-5 (MFI) zeolite (trade name: Mizuka Sieves EX122, manufactured by Mizusawa Chemical Industry Co., Ltd .: acid strength -7) was added to a 0.1 mol (M) potassium nitrate [K (NO 3 ) 2 ] aqueous solution. The solution was placed in 200 ml, stirred at a temperature of 80 ° C. for 24 hours, filtered and washed. Subsequently, the filtered washing product was dried at a temperature of 110 ° C. for 3 hours. Next, the dried product was put into 200 ml of 0.1 mol (M) cobalt nitrate [Co (NO 3 ) 2 ] aqueous solution, stirred at a temperature of 80 ° C. for 24 hours, filtered and washed. The filtered and washed product was then dried at 110 ° C. for 3 hours and further calcined at 500 ° C. for 4 hours to obtain a cobalt (Co) / potassium (K) ion exchange ZSM-5 (MFI) zeolite. . This catalyst had a cobalt (Co) loading of 2.24% by weight and a potassium (K) loading of 1.3% by weight.
　こうして製造した本発明による脱硝触媒を用いて、上記実施例１４の場合と同様にして、本発明の燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を実施した。得られた脱硝触媒性能の評価試験の結果を、下記の表９にあわせて示した。
（実施例１８）
　上記実施例１４の場合と同様にして、本発明の燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を、前記表１に示す試験条件で実施するが、上記実施例１４の場合と異なる点は、本発明の脱硝触媒として、－７のハメットの酸度関数Ｈ０に相当する酸強度を有するナトリウム型ゼオライトであるＺＳＭ－５（ＭＦＩ）ゼオライトにコバルト（Ｃｏ）およびストロンチウム（Ｓｒ）を担持させた触媒を用いた点にある。 Using the denitration catalyst according to the present invention thus produced, a denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method of the present invention was carried out in the same manner as in Example 14. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 9 below.
(Example 18)
In the same manner as in Example 14, the denitration catalyst performance evaluation test corresponding to the method for purifying combustion exhaust gas of the present invention is performed under the test conditions shown in Table 1 above, but differs from the case of Example 14 above. As a denitration catalyst of the present invention, cobalt (Co) and strontium (Sr) are supported on ZSM-5 (MFI) zeolite, which is a sodium type zeolite having an acid strength corresponding to Hammett acidity function H 0 of −7. This is in the point of using a new catalyst.
　この脱硝触媒を、つぎのようにして製造した。まず、市販のＺＳＭ－５（ＭＦＩ）ゼオライト（商品名ミズカシーブスＥＸ１２２、水澤化学工業株式会社製：酸強度－７）１０ｇを、０．１モル（Ｍ）の硝酸ストロンチウム［Ｓｒ（ＮＯ３）２］水溶液２００ｍｌに入れて、温度８０℃で、２４時間攪拌した後、濾過して洗浄した。ついで濾過洗浄物を、温度１１０℃で、３時間乾燥した。つぎに乾燥物を、０．１モル（Ｍ）の硝酸コバルト［Ｃｏ（ＮＯ３）２］水溶液２００ｍｌに入れ、温度８０℃で、２４時間攪拌した後、濾過して洗浄した。ついで濾過洗浄物を、温度１１０℃で、３時間乾燥し、さらに温度５００℃で、４時間焼成することにより、コバルト（Ｃｏ）／ストロンチウム（Ｓｒ）イオン交換ＺＳＭ－５（ＭＦＩ）ゼオライトを得た。この触媒のコバルト（Ｃｏ）担持量は１．２０重量％、ストロンチウム（Ｓｒ）担持量は２．７０重量％であった。 This denitration catalyst was produced as follows. First, 10 g of commercially available ZSM-5 (MFI) zeolite (trade name: Mizuka Sieves EX122, manufactured by Mizusawa Chemical Industry Co., Ltd .: acid strength -7) was added to 0.1 mol (M) of strontium nitrate [Sr (NO 3 ) 2 ]. The solution was placed in 200 ml of an aqueous solution, stirred at a temperature of 80 ° C. for 24 hours, and then washed by filtration. Subsequently, the filtered washing product was dried at a temperature of 110 ° C. for 3 hours. Next, the dried product was put into 200 ml of 0.1 mol (M) cobalt nitrate [Co (NO 3 ) 2 ] aqueous solution, stirred at a temperature of 80 ° C. for 24 hours, filtered and washed. The filtered and washed product was then dried at 110 ° C. for 3 hours and further calcined at 500 ° C. for 4 hours to obtain a cobalt (Co) / strontium (Sr) ion exchange ZSM-5 (MFI) zeolite. . This catalyst had a cobalt (Co) loading of 1.20% by weight and a strontium (Sr) loading of 2.70% by weight.
　こうして製造した本発明による脱硝触媒を用いて、上記実施例１４の場合と同様にして、本発明の燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を実施したが、この実施例１８では、ＮＯ濃度が１０００ｐｐｍの排ガスについて、還元剤としてのエタノールを濃度７００ｐｐｍで使用した。得られた脱硝触媒性能の評価試験の結果を、下記の表９にあわせて示した。なお、下記の表９には、比較のために、前述の比較例２と４の脱硝触媒性能の評価試験の結果をあわせて示した。 Using the thus-produced denitration catalyst according to the present invention, a denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method of the present invention was carried out in the same manner as in Example 14. In Example 18, For exhaust gas having a NO concentration of 1000 ppm, ethanol as a reducing agent was used at a concentration of 700 ppm. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 9 below. Table 9 below also shows the results of the denitration catalyst performance evaluation test of Comparative Examples 2 and 4 described above for comparison.
Figure JPOXMLDOC01-appb-T000009
 　上記表９の結果から明らかなように、本発明による実施例１４～１８の脱硝試験においては、比較例２と４の脱硝試験に比べて、いずれも高い脱硝率を示しており、本発明による脱硝触媒が、反応温度２５０℃で高い触媒性能を有することが分かる。
Figure JPOXMLDOC01-appb-T000009
 As is clear from the results of Table 9 above, the denitration tests of Examples 14 to 18 according to the present invention all showed a higher denitration rate than the denitration tests of Comparative Examples 2 and 4, and according to the present invention. It can be seen that the denitration catalyst has high catalytic performance at a reaction temperature of 250 ° C.
　ここで、脱硝性能を示す量として、上記の本発明による実施例１４～１８の脱硝試験における反応速度定数Ｋを算出し、得られた反応速度定数Ｋの結果を、下記の表１０に示した。なお、下記の表１０には、比較のために、前述の比較例２および４の脱硝試験における反応速度定数Ｋの結果をあわせて示した。　 Here, as an amount indicating the denitration performance, the reaction rate constant K in the denitration tests of Examples 14 to 18 according to the present invention was calculated, and the results of the obtained reaction rate constant K are shown in Table 10 below. . In Table 10, the results of the reaction rate constant K in the denitration tests of Comparative Examples 2 and 4 are also shown for comparison. *
Figure JPOXMLDOC01-appb-T000010
 　上記表１０の結果から明らかなように、本発明による実施例１４～１８の脱硝試験においては、比較例２および４の脱硝試験の場合より、いずれも反応速度定数Ｋが高く、窒素酸化物（ＮＯｘ）を効率良く低減させていることが分かる。
（実施例１９）
　つぎに、脱硝触媒が、高濃度の硫黄酸化物（ＳＯｘ）の存在下においても、窒素酸化物を効果的に低減できることを確認するために、本発明による脱硝触媒について、三酸化硫黄（ＳＯ３）に対する耐性をテストした。
Figure JPOXMLDOC01-appb-T000010
 As is apparent from the results in Table 10 above, in the denitration tests of Examples 14 to 18 according to the present invention, both of the reaction rate constants K were higher than in the denitration tests of Comparative Examples 2 and 4, and nitrogen oxides ( It can be seen that NOx) is efficiently reduced.
(Example 19)
Next, in order to confirm that the denitration catalyst can effectively reduce nitrogen oxides even in the presence of a high concentration of sulfur oxide (SOx), the denitration catalyst according to the present invention is treated with sulfur trioxide (SO 3). ).
　前記の表４に示す条件で、一定時間、三酸化硫黄（ＳＯ３）を含むガスに脱硝触媒をさらす耐性試験を実施し、本発明による脱硝触媒の硫黄酸化物（ＳＯｘ）に対する耐性をテストした。 Under the conditions shown in Table 4 above, a resistance test in which the denitration catalyst was exposed to a gas containing sulfur trioxide (SO 3 ) for a certain period of time was performed, and the resistance of the denitration catalyst according to the present invention to sulfur oxide (SOx) was tested. .
　実施例１９では、本発明による実施例１４において製造したＣｏ／Ｂａ‐ＺＳＭ－５（ＭＦＩ）ゼオライトを、脱硝触媒性能評価試験を実施する前に、三酸化硫黄（ＳＯ３）を含むガスに３０時間さらした。なお、三酸化硫黄（ＳＯ３）は、定量送液ポンプを用いて蒸発管に送り、蒸発器内でガス化してから、反応管に流入した。 In Example 19, the Co / Ba-ZSM-5 (MFI) zeolite produced in Example 14 according to the present invention was added to a gas containing sulfur trioxide (SO 3 ) before performing a denitration catalyst performance evaluation test. Exposed time. In addition, sulfur trioxide (SO 3 ) was sent to the evaporation pipe using a fixed liquid feed pump, gasified in the evaporator, and then flowed into the reaction pipe.
　ついで、この三酸化硫黄さらし後の脱硝触媒を用いて、上記実施例１４の場合と同様に、燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を実施した。得られた脱硝触媒性能の評価試験の結果を、下記の表１１に示した。
（実施例２０および２１）
　上記実施例１９の場合と同様にして、本発明による脱硝触媒について、三酸化硫黄（ＳＯ３）に対する耐性をテストするが、上記実施例１９の場合と異なる点は、実施例２０では、本発明による実施例１７において製造したＣｏ／Ｋ‐ＺＳＭ－５（ＭＦＩ）ゼオライトを、脱硝触媒性能評価試験を実施する前に、三酸化硫黄（ＳＯ３）を含むガスに２０時間さらした点にある。また、実施例２１では、本発明による実施例１７において製造したＣｏ／Ｋ‐ＺＳＭ－５（ＭＦＩ）ゼオライトを、脱硝触媒性能評価試験を実施する前に、三酸化硫黄（ＳＯ３）を含むガスに５４時間さらした点にある。 Next, using this denitration catalyst after exposure to sulfur trioxide, a denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method was conducted in the same manner as in Example 14 above. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 11 below.
(Examples 20 and 21)
In the same manner as in Example 19, the denitration catalyst according to the present invention was tested for resistance to sulfur trioxide (SO 3 ). The Co / K-ZSM-5 (MFI) zeolite produced in Example 17 according to the present invention was exposed to a gas containing sulfur trioxide (SO 3 ) for 20 hours before performing the denitration catalyst performance evaluation test. In Example 21, the Co / K-ZSM-5 (MFI) zeolite produced in Example 17 according to the present invention was subjected to a gas containing sulfur trioxide (SO 3 ) before the denitration catalyst performance evaluation test. Is exposed to 54 hours.
　ついで、これらの三酸化硫黄さらし後の脱硝触媒を用いて、上記実施例１９の場合と同様に、燃焼排ガスの浄化方法に対応する脱硝触媒性能評価試験を実施した。得られた脱硝触媒性能の評価試験の結果を、下記の表１１にあわせて示した。 Then, using these denitration catalysts after exposure to sulfur trioxide, a denitration catalyst performance evaluation test corresponding to the combustion exhaust gas purification method was conducted in the same manner as in Example 19. The results of the evaluation test of the obtained NOx removal catalyst performance are shown in Table 11 below.
Figure JPOXMLDOC01-appb-T000011
 　上記表１１の結果から明らかなように、本発明の実施例１９～２１の三酸化硫黄さらし後の脱硝触媒による脱硝試験においては、いずれも高い脱硝率を示しており、本発明による脱硝触媒は、例えば船舶用機関から排出される排ガスに多く含まれる硫黄酸化物（ＳＯｘ）の耐性にも優れていることが分かる。
Figure JPOXMLDOC01-appb-T000011
 As is clear from the results in Table 11 above, in the denitration test using the denitration catalyst after exposure to sulfur trioxide in Examples 19 to 21 of the present invention, all showed a high denitration rate. For example, it turns out that it is excellent also in the tolerance of the sulfur oxide (SOx) contained abundantly in the exhaust gas discharged | emitted from the engine for ships.
　このように見てくると明らかなように、本発明の燃焼排ガスの浄化方法によれば、高濃度の窒素酸化物（ＮＯｘ）および硫黄酸化物（ＳＯｘ）が存在し、しかも排ガス温度が３００℃以下と低い、例えば船舶用機関すなわち船舶用大型ディーゼルエンジン、工場や発電所、地域冷暖房などの大規模ボイラー等から排出される燃焼排ガスから、窒素酸化物を効果的に低減することが可能である。 As is apparent from this, according to the method for purifying combustion exhaust gas of the present invention, high concentrations of nitrogen oxides (NOx) and sulfur oxides (SOx) are present, and the exhaust gas temperature is 300 ° C. Nitrogen oxides can be effectively reduced from combustion exhaust gas discharged from large-scale boilers such as marine engines, ie large marine diesel engines, factories and power plants, district heating and cooling, etc. .

Claims (12)

  1. 　還元剤としてアルコールを添加した燃焼排ガスを、ナトリウム型ゼオライトにコバルトを担持させた脱硝触媒に、１８０～３００℃の温度において接触させることにより、排ガス中の窒素酸化物を除去することを特徴とする、燃焼排ガスの浄化方法。 Combustion exhaust gas to which alcohol is added as a reducing agent is contacted with a denitration catalyst in which cobalt is supported on sodium-type zeolite at a temperature of 180 to 300 ° C., thereby removing nitrogen oxides in the exhaust gas. A method for purifying combustion exhaust gas.
  2. 　脱硝触媒が、ナトリウム型ゼオライトにコバルトおよび水素を担持させた脱硝触媒であることを特徴とする、請求項１に記載の燃焼排ガスの浄化方法。 The method for purifying combustion exhaust gas according to claim 1, wherein the denitration catalyst is a denitration catalyst in which cobalt and hydrogen are supported on sodium-type zeolite.
  3. 　脱硝触媒が、ナトリウム型ゼオライトにコバルトおよびアルカリ金属またはアルカリ土類金属を担持させた脱硝触媒であることを特徴とする、請求項１に記載の燃焼排ガスの浄化方法。 The method for purifying combustion exhaust gas according to claim 1, wherein the denitration catalyst is a denitration catalyst in which cobalt and alkali metal or alkaline earth metal are supported on sodium-type zeolite.
  4. 　還元剤が、イソプロピルアルコール、エタノール、またはメタノールであることを特徴とする、請求項１～３のうちのいずれか一項に記載の燃焼排ガスの浄化方法。 The method for purifying combustion exhaust gas according to any one of claims 1 to 3, wherein the reducing agent is isopropyl alcohol, ethanol, or methanol.
  5. 　ナトリウム型ゼオライトが、ＺＳＭ－５（ＭＦＩ）型ゼオライトまたはモルデナイト（ＭＯＲ）型ゼオライトであることを特徴とする、請求項１～３のうちのいずれか一項に記載の燃焼排ガスの浄化方法。 The method for purifying combustion exhaust gas according to any one of claims 1 to 3, wherein the sodium-type zeolite is a ZSM-5 (MFI) -type zeolite or a mordenite (MOR) -type zeolite.
  6. 　燃焼排ガスが、Ｃ重油を燃焼した排ガスであることを特徴とする、請求項２または３に記載の燃焼排ガスの浄化方法。 The method for purifying combustion exhaust gas according to claim 2 or 3, wherein the combustion exhaust gas is exhaust gas obtained by burning C heavy oil.
  7. 　アルカリ金属が、カリウム（Ｋ）であり、アルカリ土類金属が、カルシウム（Ｃａ）、ストロンチウム（Ｓｒ）、およびバリウム（Ｂａ）よりなる群の中から選ばれた少なくとも１種の金属であることを特徴とする、請求項３に記載の燃焼排ガスの浄化方法。 The alkali metal is potassium (K), and the alkaline earth metal is at least one metal selected from the group consisting of calcium (Ca), strontium (Sr), and barium (Ba). The method for purifying combustion exhaust gas according to claim 3, wherein the method is characterized in that:
  8. 　請求項１に記載の燃焼排ガスの浄化方法に使用する脱硝触媒であって、ナトリウム型ゼオライトにコバルトを担持させたものであり、還元剤としてアルコールを添加した燃焼排ガスに対し、１８０～３００℃の温度において接触させることを特徴とする、脱硝触媒。 A denitration catalyst for use in the method for purifying combustion exhaust gas according to claim 1, wherein cobalt is supported on sodium-type zeolite, and the combustion exhaust gas to which alcohol is added as a reducing agent has a temperature of 180 to 300 ° C. A denitration catalyst which is contacted at a temperature.
  9. 　脱硝触媒が、ナトリウム型ゼオライトにコバルトおよび水素を担持させた脱硝触媒であることを特徴とする、請求項８に記載の脱硝触媒。 The denitration catalyst according to claim 8, wherein the denitration catalyst is a denitration catalyst in which cobalt and hydrogen are supported on sodium-type zeolite.
  10. 　脱硝触媒が、ナトリウム型ゼオライトにコバルトおよびアルカリ金属またはアルカリ土類金属を担持させた脱硝触媒であることを特徴とする、請求項８に記載の脱硝触媒。 The denitration catalyst according to claim 8, wherein the denitration catalyst is a denitration catalyst in which cobalt and alkali metal or alkaline earth metal are supported on sodium-type zeolite.
  11. 　ナトリウム型ゼオライトが、ＺＳＭ－５（ＭＦＩ）型ゼオライトまたはモルデナイト（ＭＯＲ）型ゼオライトからなるものであることを特徴とする、請求項８～１０のうちのいずれか一項に記載の脱硝触媒。 The denitration catalyst according to any one of claims 8 to 10, wherein the sodium-type zeolite is composed of a ZSM-5 (MFI) -type zeolite or a mordenite (MOR) -type zeolite.
  12. 　アルカリ金属が、カリウム（Ｋ）であり、アルカリ土類金属が、カルシウム（Ｃａ）、ストロンチウム（Ｓｒ）、およびバリウム（Ｂａ）よりなる群の中から選ばれた少なくとも１種の金属であることを特徴とする、請求項１０に記載の脱硝触媒。 The alkali metal is potassium (K), and the alkaline earth metal is at least one metal selected from the group consisting of calcium (Ca), strontium (Sr), and barium (Ba). The denitration catalyst according to claim 10, wherein
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WO2021114208A1 (en) 2019-12-13 2021-06-17 南开大学 Denitration catalyst and denitration method using the catalyst
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WO2014088083A1 (en) * 2012-12-07 2014-06-12 日立造船株式会社 Base material for producing honeycomb structure, method for producing same, method for producing honeycomb structure, and method for producing honeycomb catalyst
US11224839B2 (en) 2014-11-12 2022-01-18 Hitachi Zosen Corporation Aldehyde decomposition catalyst, and exhaust gas treatment apparatus and exhaust gas treatment method
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