CN109701524A

CN109701524A - Remove the catalyst and preparation method thereof of nitrogen oxides

Info

Publication number: CN109701524A
Application number: CN201711016771.XA
Authority: CN
Inventors: 任丽萍; 李斌; 徐建军; 滕加伟
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2017-10-26
Filing date: 2017-10-26
Publication date: 2019-05-03

Abstract

The present invention relates to a kind of catalyst for removing nitrogen oxides, mainly solve the problem of to exist in the prior art that catalyst is active low under cryogenic or poor selectivity cannot be removed effectively nitrogen oxides under the high temperature conditions.The present invention is by using sol-gel method (SOL-GEL method), by the aqueous solution or alcoholic solution of a certain amount of aluminium isopropoxide, it is added drop-wise in inorganic silver, copper, iron or/and aqueous solution of chromium salt, by plastic, aging, drying and roasting and etc. be made alumina load catalyst, the technical solution modified again with IVB, VB family metal oxide, preferably solves the problems, such as this.The catalyst is used to remove in the reaction of nitrous oxides exhaust gas, can effective nitrogen oxides reduction, not only there is high catalytic activity and longer service life, and prepare easy, price is lower, is suitble to industrial application.

Description

Remove the catalyst and preparation method thereof of nitrogen oxides

Technical field

The present invention relates to catalyst of a kind of nitrogen oxides reduction and preparation method thereof, more particularly to a kind of carbon monoxide Catalyst of catalyzing and reducing nitrogen oxides and preparation method thereof.

Background technique

With the fast development of countries in the world modern industry, atmosphere pollution have become one get worse global ask Topic, NOx is generally acknowledged one of Air Pollutant Discharge.China is the developing country based on fire coal, when longer from now on In, energy resource structure of the China based on coal will not change, and the nitrogen oxides that fire coal generates is to generate acid rain, photochemical fog And the principal element that relevant environment is destroyed.Acid rain can cause soil productivity, crops, forest, inland lake, building etc. Injury.In addition, NOx can induce many human body diseases, especially there are high risks to upgrowth and development of children to human health.Choosing Selecting property catalytic reduction method is to be translated into N with additional reducing agent removing NOx₂And O₂Method, referred to as SCR (Selective Catalytic Reduction) method, wherein with NH₃NH as reducing agent₃- SCR method is to apply most, technology most in the world A kind of mature denitration technology is invented by Eegelhard company, the U.S., and has applied for patent in nineteen fifty-nine, and Japan takes the lead in The 1970s is to the method achieve industrialization.It is to be in temperature using catalyst iron, vanadium, chromium, cobalt, nickel and alkali metal NOx is reduced to N at 200~450 DEG C₂.Its main chemical reaction is as follows:

4NH₃+ 6NO=5N₂+6H₂O (1)

8NH₃+6NO₂=7N₂+12H₂O (2)

In the case where no catalyst, these reaction can only within the scope of very narrow temperature (980 DEG C or so) progress, lead to It crosses and selects suitable catalyst, reaction temperature can be reduced, and can extend to the 290~430 of suitable power plant's actual condition DEG C range.Therefore, the selection of catalyst is crucial in SCR method.Requirement to catalyst is active high, service life length, good economy performance Do not generate secondary pollution.

Non-selective reductant method refers under the action of catalyst, with CO, H in original atmosphere₂、CH₄Deng for reducing agent, make NO catalysis reduction generates N₂, while the O in reducing agent and gas source₂Reaction generates CO₂And H₂O.In this denitrification process, reaction Need to be by means of catalyst action, and reducing agent and NO_xAnd O₂All react, non-selectivity, so referred to as non-selective catalytic is also Original reaction.Custom catalysts have platinum and palladium, due to releasing a large amount of heat in reaction process, waste heat boiler should be arranged in process and give Recycling, the method fuel consumption is big, and noble metal is needed to make catalyst, need to add heat recovery apparatus, and investment is big, thus it is external gradually It is eliminated.Patent in relation to the removing of ammine selectivity catalytic reduction at low temperature NOx has very much.

United States Patent (USP) US6685897 discloses a kind of catalyst that molecular sieve is exchanged with alkali metal cation, the catalysis Agent has high specific surface and big pore structure, and catalyst operating temperature range is 150~450 DEG C.

United States Patent (USP) US4925825 proposes a kind of using ammonia as reducing agent, the method for catalytic reduction of NOx, the catalysis used Agent is with TiO₂-V₂O₅-Mo₂O₃For active component, it is greater than 350 DEG C using temperature, this is that one kind is suitable for using under mesophilic condition Catalyst for reduction of oxides of nitrogen.

Chinese patent CN01131952.6 discloses a kind of catalyst of ammonia selective reducing nitrogen oxide, which is Copper, the Mn complex oxide catalyst of alumina load, under conditions of 150~350 DEG C of reaction temperature, catalyst has high Activity and stability.

Chinese patent CN87100737A discloses a kind of catalysis by nitrogen oxide selective reduction for nitrogen in the presence of ammonia Agent, the catalyst also contain a small amount of oxide selected from vanadium and copper as helping and urge using cobalt oxide and zeolite as main active component Agent.The catalyst belongs to mixed oxide type catalyst, at 350 DEG C, the NOx of 1600ppm can be made to reduce 90%.

Chinese patent CN201410527707.8 disclose a kind of reduction of nitrogen oxides ammonia selective catalysis catalyst and its Include active component Fe using, catalyst composition, rare earth element auxiliary agent (La, Ce or Sm) and molecular sieve carrier (Beta or The mixture of Beta and ZSM-5).It, can be under excess oxygen by nitrogen oxides using above-mentioned catalyst using ammonia as reducing agent It is converted into harmless nitrogen.

Chinese patent CN201410781282.3 discloses a kind of for the compound of ammine selectivity catalytic reduction nitrous oxides Oxide catalyst and preparation method thereof is mainly used in the purification of the nitrogen oxides in factory's flue gas and motor-vehicle tail-gas. The catalyst is mainly made of the rare earth oxide of manganese oxide and different content, it is characterised in that catalyst is to ammonia selective catalyst Nitrogen oxides reduction reaction has extraordinary low temperature active and very strong water resistant and sulfur poisoning resistance, in 50-300 DEG C of temperature The conversion ratio of range nitrogen oxides can reach 80% or more.

We are water-soluble by a certain amount of aluminium isopropoxide by using sol-gel method for the reaction for removing nitrogen oxides Liquid or alcoholic solution are added drop-wise in inorganic silver salt solution, by plastic, aging, drying and roasting and etc. that aluminium oxide is made is negative The catalyst of load, then modified with IVB, VB family metal oxide, obtained catalyst is used to remove the reaction of nitrogen oxides In, can effective nitrogen oxides reduction, catalyst have high activity and highly selective and longer service life.

Summary of the invention

The first technical problem to be solved by the present invention be existing ammonia selective reducing nitrogen oxide catalyst activity it is not high, The problem of stability difference, provides a kind of catalyst for removing nitrogen oxides, which has reactivity height, stability high Feature.

The second technical problem to be solved by the present invention is to provide the corresponding reduction of one of one kind and solution technical problem The preparation method of nitrogen oxide catalyst.The characteristics of this method has cost of material low, and preparation is simple.

The third technical problem to be solved by the present invention be the catalyst activity of existing ammonia selective reducing nitrogen oxide not High, stability difference problem provides a kind of method of new Carbon monoxide reduction nitrogen oxides, and this method is for removing nitrogen oxidation When the reaction of object, have the characteristics that catalyst activity is high, stability is high.

One of to solve above-mentioned technical problem, The technical solution adopted by the invention is as follows: a kind of removing nitrogen oxides is urged Agent, catalyst include following components by weight percentage:

A) 80~95% aluminium oxide；

B) 0~3% at least one of periodic table of elements Section IV B or VB race metal oxide are selected from.

C) 5~15% selected from least one of Cu, Ag, Fe, Cr element or its oxide；

D) 0~5% selected from least one of Ce, Mn metal oxide.

In above-mentioned technical proposal, it is preferred that the content of component d) is 0.1~3%；More preferably 0.2~2%.

In above-mentioned technical proposal, it is preferred that component c) is selected from Ag, and component d) is selected from Mn.

In above-mentioned technical proposal, it is preferred that component c) is selected from Cr, and component d) is selected from Ce.

In above-mentioned technical proposal, it is preferred that the content of the component c) in terms of catalyst weight percent is 2~10%.

In above-mentioned technical proposal, it is preferred that the metal oxide in periodic table of elements Section IV B or VB race

Preferably one of titanium oxide, zirconium oxide, vanadium oxide or niobium oxide or at least one.

In above-mentioned technical proposal, it is preferred that do not contain element silicon or its oxide in catalyst.

In above-mentioned technical proposal, it is preferred that in terms of catalyst weight percent, the content of bismuth oxide is 0.1~1.8%； It is furthermore preferred that the content of bismuth oxide is 0.5~1.5%.

To solve above-mentioned technical problem two, The technical solution adopted by the invention is as follows: the catalyst of removing nitrogen oxides Preparation method, comprising the following steps:

A) aqueous solution or alcoholic solution I is made in aluminium isopropoxide；

B) silver soluble, copper, iron or/and chromic salts are dissolved in water, obtain solution II；

C) above-mentioned solution II is added dropwise in solution I, heating plastic obtains jelly III；

D) it removes to roast after solvent in jelly III and obtains catalyst precarsor IV；

E) catalyst needed for being obtained after catalyst precarsor IV roasting.

In above-mentioned technical proposal, it is preferred that the catalyst precarsor IV that step d) is obtained first passes through the metal containing IVB and/or VB race Salting liquid is modified, then after roasting after needed for catalyst.

In above-mentioned technical proposal, it is preferred that the temperature of plastic is 90~150 DEG C, after removing the solvent in jelly, roasting Temperature is 500~1200 DEG C, and calcining time 4~8 hours, the solid after roasting ground granulation as needed, and preferred granularity is 10 ~60 mesh, using IVB, VB race metal salt solution impregnation catalyst agent precursor, the preferably time is 12~48 hours, at 80~120 DEG C It roasts after drying in 450~600 DEG C up to required catalyst.Wherein inorganic silver, copper, iron, chromic salts are selected from nitrate or oxalates At least one of.Further, gelling temperature preferred scope be 60~100 DEG C, after plastic maturing temperature preferred scope be 600~ 1000℃。

In order to solve the above-mentioned technical problem three, The technical solution adopted by the invention is as follows: a kind of nitrogen oxides reduction Method, using reducing agent and nitrogen oxides as raw material, operating pressure is 0~0.5MPa, and gas volume air speed is 600~5000h^-1, The operation temperature of reaction unit is 150~450 DEG C.

In above-mentioned technical proposal, it is preferred that operating pressure is 0~0.3MPa

In above-mentioned technical proposal, it is preferred that gas volume air speed is 800~3000h^-1。

In above-mentioned technical proposal, it is preferred that the operation temperature of reaction unit is 200~350 DEG C.

In above-mentioned technical proposal, it is preferred that reducing agent NH₃, carbon monoxide, one of hydrogen or methane or at least one Kind.

In above-mentioned technical proposal, it is preferred that reducing agent is carbon monoxide.Technical solution of the present invention, by using oxidation Aluminium is carrier, catalyst removal nitrogen oxides better performances；It is living especially when catalyst is prepared using sol-gal process Property central distribution it is more uniform, catalyst have better performance.

The present invention is single carrier by selective oxidation aluminium, and the de- of function admirable has been prepared by sol-gel method Denitrification catalyst；When preferred catalyst components b) and component c) is combined, there is more preferably catalytic performance；It can be effective gram The disadvantage that poor catalyst stability, transformation efficiency of the oxides of nitrogen be not high in the prior art is taken, by optimizing reaction condition, nitrogen oxidation Object conversion ratio achieves preferable technical effect up to 100%.

Below by embodiment, the present invention is further elaborated.

Specific embodiment

[embodiment 1]

After aluminium isopropoxide containing 95 grams of aluminium oxide is dissolved in water, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise containing 5 grams The silver nitrate solution of silver oxide, while violent electromagnetic agitation maintain 70 DEG C of oil bath temperature, load onto reflux condensing tube, and stirring three is small When after colloidal sol solidify, stop stirring, be warming up to 100 DEG C, evaporate solvent 12 hours.It is transferred to a crucible, it is small to dry 24 with infrared lamp When, it is then transferred to 700 DEG C of muffle furnace and roasts 6 hours, be crushed to 40~60 mesh to get required containing Ag₂The Ag/Al of O 5%₂O₃ Catalyst.

The reactivity worth of carbon monoxide under low temperature catalyzing and reducing nitrogen oxides is carried out on normal miniature fixed-bed reactor It investigates.Catalyst loading is 1.05 grams, and gaseous mixture group becomes NO 1.1%, CO 5%, and remaining is nitrogen, gas space velocity 2400h^-1, 250 DEG C of reaction temperature, NO conversion ratio such as table 1 shows.

[embodiment 2]

After aluminium isopropoxide containing 90 grams of aluminium oxide is dissolved in ethanol solution, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise The mixed solution of the manganese nitrate composition of silver nitrate and 3 grams of manganese oxide containing 5 grams of silver oxides, while violent electromagnetic agitation, maintain oil 70 DEG C of bath temperature, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 100 DEG C, evaporates solvent 12 hours.It is transferred to a crucible, is dried 24 hours with infrared lamp, 700 DEG C of muffle furnace is then transferred to and roasts 6 hours, be crushed to 40 ~60 mesh, then using nitric acid titanium solution incipient impregnation 12 hours containing 2 grams of titanium oxide, in 450 DEG C of Muffle furnaces after 120 DEG C of dryings It roasts up to required 2%TiO₂Modification contains Ag₂O 5%, contain MnO₂3% Ag-Mn/Al₂O₃Catalyst.

Catalyst is evaluated using the reaction condition of embodiment 1, is as a result listed in table 1.

[embodiment 3]

After aluminium isopropoxide containing 92 grams of aluminium oxide is dissolved in ethanol solution, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise The mixed solution of the manganese nitrate composition of silver nitrate and 3 grams of manganese oxide containing 5 grams of silver oxides, while violent electromagnetic agitation, maintain oil 70 DEG C of bath temperature, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 100 DEG C, evaporates solvent 12 hours.It is transferred to a crucible, is dried 24 hours with infrared lamp, 700 DEG C of muffle furnace is then transferred to and roasts 6 hours, be crushed to 40 ~60 mesh contain Ag to get required₂O 5%, contain MnO₂3% Ag-Mn/Al₂O₃Catalyst.

[embodiment 4]

After aluminium isopropoxide containing 90 grams of aluminium oxide is dissolved in ethanol solution, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise The mixed solution of the manganese nitrate composition of silver nitrate and 3 grams of manganese oxide containing 5 grams of silver oxides, while violent electromagnetic agitation, maintain oil 70 DEG C of bath temperature, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 100 DEG C, evaporates solvent 12 hours.It is transferred to a crucible, is dried 24 hours with infrared lamp, 700 DEG C of muffle furnace is then transferred to and roasts 6 hours, be crushed to 40 ~60 mesh, then using nitric acid niobium solution incipient impregnation 12 hours containing 2 grams of niobium oxide, in 450 DEG C of Muffle furnaces after 120 DEG C of dryings It roasts up to required 2%NbO₂Modification contains Ag₂O 5%, contain MnO₂3% Ag-Mn/Al₂O₃Catalyst.

[embodiment 5]

After aluminium isopropoxide containing 90 grams of aluminium oxide is dissolved in ethanol solution, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise The mixed solution of the manganese nitrate composition of silver nitrate and 3 grams of manganese oxide containing 5 grams of silver oxides, while violent electromagnetic agitation, maintain oil 70 DEG C of bath temperature, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 100 DEG C, evaporates solvent 12 hours.It is transferred to a crucible, is dried 24 hours with infrared lamp, 700 DEG C of muffle furnace is then transferred to and roasts 6 hours, be crushed to 40 ~60 mesh, then using zirconium nitrate solution incipient impregnation 12 hours containing 2 grams of zirconium oxides, in 450 DEG C of Muffle furnaces after 120 DEG C of dryings It roasts up to required 2%ZrO₂Modification contains Ag₂O 5%, contain MnO₂3% Ag-Mn/Al₂O₃Catalyst.

[embodiment 6]

After aluminium isopropoxide containing 90 grams of aluminium oxide is dissolved in ethanol solution, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise The mixed solution of the manganese nitrate composition of silver nitrate and 3 grams of manganese oxide containing 5 grams of silver oxides, while violent electromagnetic agitation, maintain oil 70 DEG C of bath temperature, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 100 DEG C, evaporates solvent 12 hours.It is transferred to a crucible, is dried 24 hours with infrared lamp, 700 DEG C of muffle furnace is then transferred to and roasts 6 hours, be crushed to 40 ~60 mesh first using nitric acid titanium solution incipient impregnation 12 hours containing 0.5 gram of titanium oxide, then use and contain 1.5 grams of zirconium oxides It zirconium nitrate solution incipient impregnation 12 hours, roasts after 120 DEG C of dryings in 450 DEG C of Muffle furnaces up to required 0.5%TiO₂With 1.5%ZrO₂Modification contains Ag₂O 5%, contain MnO₂3% Ag-Mn/Al₂O₃Catalyst.

[embodiment 7]

After aluminium isopropoxide containing 90 grams of aluminium oxide is dissolved in ethanol solution, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise The mixed solution of the manganese nitrate composition of silver nitrate and 3 grams of manganese oxide containing 5 grams of silver oxides, while violent electromagnetic agitation, maintain oil 70 DEG C of bath temperature, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 100 DEG C, evaporates solvent 12 hours.It is transferred to a crucible, is dried 24 hours with infrared lamp, 700 DEG C of muffle furnace is then transferred to and roasts 6 hours, be crushed to 40 ~60 mesh first using nitric acid titanium solution incipient impregnation 12 hours containing 1.5 grams of titanium oxide, then use and contain 0.5 gram of zirconium oxide It zirconium nitrate solution incipient impregnation 12 hours, roasts after 120 DEG C of dryings in 450 DEG C of Muffle furnaces up to required 1.5%TiO₂With 0.5%ZrO₂Modification contains Ag₂O 5%, contain MnO₂3% Ag-Mn/Al₂O₃Catalyst.

[embodiment 8]

After aluminium isopropoxide containing 90 grams of aluminium oxide is dissolved in ethanol solution, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise The mixed solution of the manganese nitrate composition of silver nitrate and 3 grams of manganese oxide containing 5 grams of silver oxides, while violent electromagnetic agitation, maintain oil 70 DEG C of bath temperature, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 100 DEG C, evaporates solvent 12 hours.It is transferred to a crucible, is dried 24 hours with infrared lamp, 700 DEG C of muffle furnace is then transferred to and roasts 6 hours, be crushed to 40 ~60 mesh, first using Ammonium Vanadate Solution incipient impregnation 12 hours containing 0.2 gram of vanadic anhydride, then using containing 1.8 grams of oxidations The zirconium nitrate solution incipient impregnation of zirconium 12 hours roasts after 120 DEG C of dryings in 450 DEG C of Muffle furnaces up to required 0.2%V₂O₅With 1.8%ZrO₂Modification contains Ag₂O 5%, contain MnO₂3% Ag-Mn/Al₂O₃Catalyst.

[embodiment 9]

After aluminium isopropoxide containing 90 grams of aluminium oxide is dissolved in ethanol solution, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise The mixed solution of the manganese nitrate composition of silver nitrate and 3 grams of manganese oxide containing 5 grams of silver oxides, while violent electromagnetic agitation, maintain oil 70 DEG C of bath temperature, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 100 DEG C, evaporates solvent 12 hours.It is transferred to a crucible, is dried 24 hours with infrared lamp, 700 DEG C of muffle furnace is then transferred to and roasts 6 hours, be crushed to 40 ~60 mesh, first using Ammonium Vanadate Solution incipient impregnation 12 hours containing 1.8 grams of vanadic anhydrides, then using containing 0.2 gram of oxidation The zirconium nitrate solution incipient impregnation of zirconium 12 hours roasts after 120 DEG C of dryings in 450 DEG C of Muffle furnaces up to required 1.8%V₂O₅With 0.2%ZrO₂Modification contains Ag₂O 5%, contain MnO₂3% Ag-Mn/Al₂O₃Catalyst.

[embodiment 10]

After aluminium isopropoxide containing 80 grams of aluminium oxide is dissolved in water, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise containing 15 grams The mixed solution of the manganese nitrate of the silver nitrate of silver oxide and 2 grams of manganese oxide composition, while violent electromagnetic agitation, maintain oil bath temperature 70 DEG C, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 150 DEG C, evaporates solvent 12 hours. It is transferred to a crucible, is dried 24 hours with infrared lamp, 500 DEG C of muffle furnace is then transferred to and roasts 8 hours, be crushed to 40~60 mesh, Again using zirconium nitrate solution incipient impregnation 12 hours containing 3 grams of zirconium oxides, roasted after 80 DEG C of dryings in 600 DEG C of Muffle furnaces to obtain the final product Required 3%ZrO₂Modification contains Ag₂O 15%, contain MnO₂2% Ag-Mn/Al₂O₃Catalyst.

[embodiment 11]

After aluminium isopropoxide containing 80 grams of aluminium oxide is dissolved in water, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise containing 12 grams The mixed solution of the cerous nitrate of the chromium+oxalic acid of chromium oxide and 5 grams of cerium oxide composition, while violent electromagnetic agitation, maintain oil bath temperature 70 DEG C, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 90 DEG C, evaporates solvent 20 hours. It is transferred to a crucible, is dried 24 hours with infrared lamp, 1200 DEG C of muffle furnace is then transferred to and roasts 4 hours, be crushed to 40~60 mesh, Again using Ammonium Vanadate Solution incipient impregnation 48 hours containing 3 grams of vanadic anhydrides, roasted after 100 DEG C of dryings in 550 DEG C of Muffle furnaces It burns up to required 3%V₂O₅Modification contains Cr₂O₃12%, contain CeO₂5% Cr-Ce/Al₂O₃Catalyst.

[embodiment 12]

After aluminium isopropoxide containing 85 grams of aluminium oxide is dissolved in water, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise containing 13 grams The iron nitrate solution of iron oxide, while violent electromagnetic agitation maintain 70 DEG C of oil bath temperature, load onto reflux condensing tube, and stirring three is small When after colloidal sol solidify, stop stirring, be warming up to 150 DEG C, evaporate solvent 12 hours.It is transferred to a crucible, it is small to dry 24 with infrared lamp When, it is then transferred to 500 DEG C of muffle furnace and roasts 8 hours, be crushed to 40~60 mesh, then using the niobium oxalate for containing 2 grams of columbium dioxides It solution incipient impregnation 12 hours, roasts after 120 DEG C of dryings in 600 DEG C of Muffle furnaces up to required 2%NbO₂Modification contains Fe₂O₃ 13% Fe/Al₂O₃Catalyst.

[embodiment 13]

After aluminium isopropoxide containing 90 grams of aluminium oxide is dissolved in ethanol solution, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise Copper nitrate solution containing 8 grams of copper oxide, while violent electromagnetic agitation maintain 70 DEG C of oil bath temperature, load onto reflux condensing tube, stir Colloidal sol solidifies after three hours, stops stirring, is warming up to 150 DEG C, evaporates solvent 8 hours.It is transferred to a crucible, dries 24 with infrared lamp Hour, it is then transferred to 800 DEG C of muffle furnace and roasts 6 hours, be crushed to 40~60 mesh, then using the titanium chloride for containing 2 grams of titanium oxide It solution incipient impregnation 48 hours, roasts after 120 DEG C of dryings in 500 DEG C of Muffle furnaces up to required 2%TiO₂Modification contains CuO 8% Cu/Al₂O₃Catalyst.

[embodiment 14]

After aluminium isopropoxide containing 90 grams of aluminium oxide is dissolved in ethanol solution, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise The mixed solution of the manganese nitrate composition of silver nitrate and 1 gram of manganese oxide containing 8 grams of silver oxides, while violent electromagnetic agitation, maintain oil 70 DEG C of bath temperature, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 150 DEG C, evaporates solvent 12 hours.It is transferred to a crucible, is dried 24 hours with infrared lamp, 500 DEG C of muffle furnace is then transferred to and roasts 8 hours, be crushed to 40 ~60 mesh, then using zirconium nitrate solution incipient impregnation 12 hours containing 1 gram of zirconium oxide, in 600 DEG C of Muffle furnaces after 120 DEG C of dryings It roasts up to required 1%ZrO₂Modification contains Ag₂O 8%, contain MnO₂1% Ag-Mn/Al₂O₃Catalyst.

[embodiment 15]

After aluminium isopropoxide containing 85 grams of aluminium oxide is dissolved in water, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise containing 10 grams The mixed solution of the cerous nitrate of the chromium+oxalic acid of chromium oxide and 2 grams of cerium oxide composition, while violent electromagnetic agitation, maintain oil bath temperature 70 DEG C, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 150 DEG C, evaporates solvent 8 hours. It is transferred to a crucible, is dried 24 hours with infrared lamp, 800 DEG C of muffle furnace is then transferred to and roasts 6 hours, be crushed to 40~60 mesh, Again using fluorine niobic acid ammonium salt solution incipient impregnation 48 hours containing 3 grams of columbium dioxides, roasted after 120 DEG C of dryings in 500 DEG C of Muffle furnaces It burns up to required 3%NbO₂Modification contains Cr₂O₃10%, contain CeO₂2% Cr-Ce/Al₂O₃Catalyst.

[embodiment 16]

After aluminium isopropoxide containing 92 grams of aluminium oxide is dissolved in water, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise containing 6 grams The iron nitrate solution of iron oxide, while violent electromagnetic agitation maintain 70 DEG C of oil bath temperature, load onto reflux condensing tube, and stirring three is small When after colloidal sol solidify, stop stirring, be warming up to 150 DEG C, evaporate solvent 12 hours.It is transferred to a crucible, it is small to dry 24 with infrared lamp When, it is then transferred to 500 DEG C of muffle furnace and roasts 8 hours, be crushed to 40~60 mesh, then is molten using the zirconium nitrate containing 2 grams of zirconium oxides It liquid incipient impregnation 12 hours, roasts after 120 DEG C of dryings in 600 DEG C of Muffle furnaces up to required 2%ZrO₂Modification contains Fe₂O₃6% Fe/Al₂O₃Catalyst.

[embodiment 17]

After aluminium isopropoxide containing 92 grams of aluminium oxide is dissolved in ethanol solution, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise Copper nitrate solution containing 5 grams of copper oxide, while violent electromagnetic agitation maintain 70 DEG C of oil bath temperature, load onto reflux condensing tube, stir Colloidal sol solidifies after three hours, stops stirring, is warming up to 150 DEG C, evaporates solvent 8 hours.It is transferred to a crucible, dries 24 with infrared lamp Hour, it is then transferred to 800 DEG C of muffle furnace and roasts 6 hours, be crushed to 40~60 mesh, then using the zirconium nitrate for containing 3 grams of zirconium oxides It solution incipient impregnation 48 hours, roasts after 120 DEG C of dryings in 500 DEG C of Muffle furnaces up to required 3%ZrO₂Modification contains CuO 5% Cu/Al₂O₃Catalyst.

[embodiment 18]

90 grams of aluminum oxide micro-spheres are taken, the mixing with the manganese nitrate of the silver nitrate for containing 5 grams of silver oxides and 3 grams of manganese oxide composition is molten Liquid steeped overnight evaporates solvent, and 700 DEG C of muffle furnace are transferred to after ground and mixed and is roasted 6 hours, then uses the nitre of 2 grams of titanium oxide Sour titanium solution incipient impregnation 12 hours roasts 2% up to conventional method preparation in 600 DEG C of Muffle furnaces after 120 DEG C of dryings TiO₂Modification contains Ag₂O 5%, contain MnO₂3% Ag-Mn/Al₂O₃Catalyst.

[embodiment 19]

85 grams of aluminum oxide micro-spheres are taken, with the mixing of the cerous nitrate of the chromium+oxalic acid for containing 10 grams of chromium oxide and 2 grams of cerium oxide composition Solution steeped overnight evaporates solvent, and 700 DEG C of muffle furnace are transferred to after ground and mixed and is roasted 6 hours, then using containing 3 grams of niobium oxide Nitric acid niobium solution incipient impregnation 48 hours, after 100 DEG C of dryings in 550 DEG C of Muffle furnaces roast up to conventional method preparation 3%NbO₂Modification contains Cr₂O₃10%, contain CeO₂2% Cr-Ce/Al₂O₃Catalyst.

[embodiment 20]

85 grams of aluminum oxide micro-spheres are taken, with the iron nitrate solution steeped overnight for containing 13 grams of iron oxide, evaporate solvent, ground and mixed After be transferred to 700 DEG C of muffle furnace and roast 6 hours, then using containing niobium oxalate solution incipient impregnation 12 hours of 2 grams of columbium dioxides, The 2%NbO up to conventional method preparation is roasted in 600 DEG C of Muffle furnaces after 120 DEG C of dryings₂Modification contains Fe₂O₃13% Fe/ Al₂O₃Catalyst.

[embodiment 21]

After aluminium isopropoxide containing 94.6 grams of aluminium oxide is dissolved in water, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise and contains The bismuth nitrate solution of 0.4 gram of bismuth oxide, the silver nitrate solution containing 5 grams of silver oxides, while violent electromagnetic agitation maintain oil bath temperature 70 DEG C, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 100 DEG C, evaporates solvent 12 hours. It is transferred to a crucible, is dried 24 hours with infrared lamp, 700 DEG C of muffle furnace is then transferred to and roasts 6 hours, be crushed to 40~60 mesh, Contain Ag up to required₂The Ag/Al of O 5%₂O₃Catalyst.

[embodiment 22]

After aluminium isopropoxide containing 94 grams of aluminium oxide is dissolved in water, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise containing 1 gram The bismuth nitrate solution of bismuth oxide, the silver nitrate solution containing 5 grams of silver oxides, while violent electromagnetic agitation maintain 70 DEG C of oil bath temperature, Reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 100 DEG C, evaporates solvent 12 hours.Transfer To a crucible, dried 24 hours with infrared lamp, be then transferred to 700 DEG C of muffle furnace and roast 6 hours, be crushed to 40~60 mesh to get It is required to contain Ag₂The Ag/Al of O 5%₂O₃Catalyst.

[embodiment 23]

After aluminium isopropoxide containing 93.6 grams of aluminium oxide is dissolved in water, is sufficiently stirred, it is placed in three-necked bottle, is added dropwise and contains The bismuth nitrate solution of 1.4 grams of bismuth oxides, the silver nitrate solution containing 5 grams of silver oxides, while violent electromagnetic agitation maintain oil bath temperature 70 DEG C, reflux condensing tube is loaded onto, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 100 DEG C, evaporates solvent 12 hours. It is transferred to a crucible, is dried 24 hours with infrared lamp, 700 DEG C of muffle furnace is then transferred to and roasts 6 hours, be crushed to 40~60 mesh, Contain Ag up to required₂The Ag/Al of O 5%₂O₃Catalyst.

Table 1

[comparative example 1]

After the silica solution of the aluminium isopropoxide and 42 grams of silica that contain 50 grams of aluminium oxide is dissolved in ethanol solution, is sufficiently stirred, It is placed in three-necked bottle, the mixed solution of the manganese nitrate composition of silver nitrate and 3 grams of manganese oxide containing 5 grams of silver oxides is added dropwise, together When violent electromagnetic agitation, maintain 70 DEG C of oil bath temperature, load onto reflux condensing tube, colloidal sol solidifies after stirring three hours, stop stirring, 100 DEG C are warming up to, is evaporated solvent 12 hours.It is transferred to a crucible, is dried 24 hours with infrared lamp, is then transferred to muffle furnace 700 DEG C roasting 6 hours, 40~60 mesh were crushed to get required containing Ag₂O 5%, contain MnO₂3% Ag-Mn/Al₂O₃-SiO₂Catalysis Agent.

[comparative example 2]

It will be hydrolyzed, be placed in three-necked bottle containing the ethyl orthosilicates of 92 grams of silica, is added dropwise containing 5 grams of silver oxides The mixed solution of the manganese nitrate of silver nitrate and 3 grams of manganese oxide composition, while violent electromagnetic agitation, maintain 70 DEG C of oil bath temperature, dress Upper reflux condensing tube, colloidal sol solidifies after stirring three hours, stops stirring, is warming up to 100 DEG C, evaporates solvent 12 hours.It is transferred to One crucible is dried 24 hours with infrared lamp, is then transferred to 700 DEG C of muffle furnace and is roasted 6 hours, is crushed to 40~60 mesh to get institute Ag need to be contained₂O 5%, contain MnO₂3% Ag-Mn/SiO₂Catalyst.

[comparative example 3]

92 grams of ZSM-5 molecular sieves are taken, with the manganese nitrate mixed solution leaching of silver nitrate and 3 grams of manganese oxide containing 5 grams of silver oxides Stain is stayed overnight, and solvent is evaporated, and 700 DEG C of muffle furnace are transferred to after ground and mixed and is roasted 6 hours, is crushed to 40~60 mesh to get required Containing Ag₂O 5%, contain MnO₂3% Ag-Mn/ZSM-5 catalyst.

[embodiment 24]

The catalyst made from Examples 1 to 20 carries out carbon monoxide under low temperature on normal miniature fixed-bed reactor The reactivity worth of catalyzing and reducing nitrogen oxides is investigated.Catalyst loading is 1.05 grams, and gaseous mixture group becomes NO 1.1%, CO 5%, remaining is nitrogen, gas space velocity 2400h^-1, 200~350 DEG C of reaction temperature, reaction result such as table 2 shows.

[embodiment 25]

It is investigated using the experiment condition of catalyst made from embodiment 15 and embodiment 21 using methane as reducing agent Influence of the reaction temperature to NO conversion ratio, is as a result listed in table 2.

Table 2

Claims

1. a kind of catalyst for removing nitrogen oxides, catalyst includes following components by weight percentage:

A) 80~95% aluminium oxide；

C) 5~15% selected from least one of Cu, Ag, Fe, Cr element or its oxide；

D) 0~5% selected from least one of Ce, Mn metal oxide.

2. it is according to claim 1 removing nitrogen oxides catalyst, it is characterised in that the content of component d) be 0.1~ 3%；Preferably 0.2~2%.

3. removing the catalyst of nitrogen oxides according to claim 1, it is characterised in that component c) is selected from Ag, and component d) is selected from Mn。

4. removing the catalyst of nitrogen oxides according to claim 1, it is characterised in that component c) is selected from Cr, and component d) is selected from Ce。

5. removing the catalyst of nitrogen oxides according to claim 1, it is characterised in that the group in terms of catalyst weight percent Dividing content c) is 2~10%.

6. removing the catalyst of nitrogen oxides according to claim 1, it is characterised in that be selected from periodic table of elements Section IV B or VB Metal oxide in race is selected from one of titanium oxide, zirconium oxide, vanadium oxide or niobium oxide or at least one.

7. removing the catalyst of nitrogen oxides according to claim 1, it is characterised in that catalyst passes through sol-gel method (SOL-GEL) it is prepared.

8. removing the catalyst of nitrogen oxides according to claim 1, it is characterised in that aluminium oxide is in catalyst with amorphous State exists, and does not have the characteristic diffraction peak of aluminium oxide in the XRD spectra of catalyst.

9. removing the preparation method of the catalyst of nitrogen oxides described in claim 7, comprising the following steps:

E) catalyst needed for being obtained after catalyst precarsor IV roasting.

10. the preparation method of removing nitrogen oxide catalyst according to claim 9, it is characterised in that step d) is obtained Catalyst precarsor IV first through modified containing IVB and/or VB race metal salt solution, then after roasting after needed for catalyst.