CN1142025C - Methane selective reducing nitrogen oxide catalyst under oxygen-enriched condition - Google Patents
Methane selective reducing nitrogen oxide catalyst under oxygen-enriched condition Download PDFInfo
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- CN1142025C CN1142025C CNB981143369A CN98114336A CN1142025C CN 1142025 C CN1142025 C CN 1142025C CN B981143369 A CNB981143369 A CN B981143369A CN 98114336 A CN98114336 A CN 98114336A CN 1142025 C CN1142025 C CN 1142025C
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- China
- Prior art keywords
- molecular sieve
- catalyst
- methane
- oxygen
- indium
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Abstract
The present invention relates to a methane selective reducing nitrogen oxide catalyst under the oxygen-enriched condition, which is prepared from active components and a carrier. The catalyst is characterized in that the active components are indium and iron; the carrier is a molecular sieve whose silicon-aluminium ratio is less than 50; the weight percentage content of indium carried by the molecular sieve is from 0.5 to 20%; the weight ratio of the molecular sieve and a ferric oxide is from 10: 0.5 to 20. The preparation method of the catalyst comprises the following steps: mechanically mixing the ferric oxide and the molecular sieve, carrying an indium salt on the molecular sieve by the method of immersion, and roasting at temperature of 500 to 900 DEG C for 3 to 6 hours. The present invention is suitable for selective reduction of nitrogen oxide compounds by using methane in the presence of large amount of oxygen.
Description
Technical field
The present invention relates to gas purification, environmental protection, fields such as Industrial Catalysis particularly use methane to eliminate oxynitrides (NO as reducing agent catalysis
x) time employed catalyst, preparation method and catalytic process.
Background technology
Oxynitrides (NO
x, i.e. NO and NO2) and be subjected to the extensive concern of countries in the world as an aspect of environmental pollution.NO in all dischargings
xIn the 55% fuel combustion product from static father (power station, Industrial Boiler, gas fired-boiler, interior alkene machine and nitric plant etc.) is arranged approximately.NH under the oxidizing atmosphere
3Select Reduction of NO
x(SCR) be acknowledged as now and from industrial waste gas, eliminate NO
xEffective method is in Japan and the industrialization of some industrially developed country.But this process NH
3Need the measure control addition, leakage or reaction not exclusively cause secondary pollution easily; The oxidized final generation NH of sulphur-containing substance in the course of reaction
4HSO
4, (NH
4)
2S
2O
7, obstruction, corrosion reaction pipeline, and make catalysqt deactivation.At the problems referred to above and NH
3Storage, equipment and expense that transportation and use etc. are expensive are necessary to explore a kind of without NH
3Make the removing method of reducing agent.Because natural gas (mainly being methane) reserves are abundant, be widely used in industrial production, and almost be present in the tail gas of each fuel, so, with the NO that discharges in the methyl hydride catalyzed reduction stationary source fuel combustion process
xBe a practicality and cheap approach.The patent of USP5149112 points out that under the oxygen-containing atmosphere, an amount of methane is reducing agent, and the Co-ZSM-5 activity of ion-exchange preparation is best.JP06,262,039 proposes under the indium catalyst action that ZSM5 molecular sieve or ferrierite support, and when aerobic existed, reducing agent methane and carbon monoxide acted on simultaneously, can effectively remove oxynitrides, JP06, what 132,139 proposition ZSM5 were molecular sieve supported is the indium catalyst of auxiliary agent with alkali metal, when aerobic existed, methane is reduction of nitrogen oxide effectively.China Patent No. points out that for the NO.951120271 patent under the oxidizing atmosphere, methane is made reducing agent, and loaded In/HZSM5 has higher conversion ratio to oxynitrides.
Summary of the invention
The object of the present invention is to provide a kind ofly under a large amount of oxygen existence conditions, only come the catalyst of selective reduction oxynitrides with methane.
The invention provides a kind of methane selective reducing nitrogen oxide catalyst under oxygen-enriched condition, it is characterized in that: this activity of such catalysts component is indium, iron, indium is supported on the natural or artificial synthetic molecular sieve, the Tie Tong peroxide of iron and molecular sieve mechanical mixture obtain, the silica alumina ratio of molecular sieve is less than 50, the weight percentage of molecular sieve supported indium is 0.5～20%, and the weight ratio of molecular sieve and iron oxide is 10: 0.5～10: 20.
Catalyst provided by the invention can be by the indium salt (In (NO with solubility
3)
3Or InCl
3) adopt immersion process for preparing, 550～900 ℃ of sintering temperatures, 3～6 hours time with the mixture of molecular sieve and iron oxide.Catalyst provided by the invention is eliminated in the reaction at oxynitrides and is used, and is reducing agent with methane only, and [CH4]/[NO] concentration ratio is 0.2～8.0 in the unstripped gas, and reaction temperature is between 350～650 ℃, and the unstripped gas air speed is 1000～100000h
-1, reaction pressure is a normal pressure.Reaction temperature the best is between 400～650 ℃, and oxygen concentration the best is between 2.0～10.0%.The present invention is a reducing agent with methane only, is the activity of such catalysts component with indium, iron only, and in very wide temperature range internal reaction function admirable, the oxynitrides conversion ratio can reach more than 90%.Method for preparing catalyst provided by the invention is simple, and reaction has the good high-temperature reactivity to selectively reducing nitrogen oxides by methane, helps technology and amplifies, and the reaction of commercial Application eliminate to(for) oxynitrides has great Practical significance.Below by embodiment in detail the present invention is described in detail.
The specific embodiment
Embodiment 1 Preparation of catalysts
Here only to contain indium 5% (weight percentage), the weight ratio of molecular sieve and iron oxide is 10: 2 In/HZSM5+Fe
2O
3(silica alumina ratio is 25) describes Preparation of catalysts used among the present invention prevailingly for example.The HZSM5 molecular sieve is provided by Catalyst Factory, Nankai Univ, Fe
2O
3Provide by Nan Shangle chemical plant, Beijing, with 0.4989 gram indium nitrate crystal (In (NO
3)
34.5H
2O) be dissolved in the 5ml deionized water, add 3.0 gram HZSM5 and 0.6 gram Fe again
2O
3Mixture, after fully stirring, left standstill 24 hours, 120 ℃ of bakings 3 hours place 700 ℃ of roastings of muffle furnace 4 hours, before the reaction, with the catalyst compressing tablet, break that to sieve out 40～60 purpose particles standby into pieces.
Methane selective reduction carbon monoxide under embodiment 2 excess oxygens
Here only to contain indium 5% (weight percentage), the weight ratio of molecular sieve and iron oxide is 10: 2 In/HZSM5+Fe
2O
3(silica alumina ratio is 25) describes activity of such catalysts test among the present invention prevailingly for example.Active testing carries out in fixed bed reactors.Before advancing reactor, nitric oxide, methane, oxygen and helium fully mix in blender, catalyst amount 0.5 gram in the active testing, and unstripped gas air speed (GHSV) is 3600h
-1, reaction pressure is a normal pressure, reactor places in the temperature control electric furnace, 350～650 ℃ of reaction temperatures.With online chromatography analysis product, catalyst activity is a standard with the conversion ratio (%) that nitric oxide is converted into nitrogen.
The reactivity of embodiment 3 different catalysts
| Catalyst | Reaction temperature (℃) |
| 350 400 450 500 550 600 650 | |
| In/HZSM5 In/HZSM5+CuO In/HZSM5+Ni 2O 3 In/HZSM5+Co 3O 4 In/HZSM5+Fe 2O 3 Ga/HZSM5+Fe 2O 3 Ga/HZSM5 | 25.1 70.2 95.8 100 99.6 93.4 76.4 1.2 3.3 6.8 9.4 15.0 11.2 12.3 3.0 20.0 36.8 47.7 49.2 44.0 33.4 23.2 56.1 86.3 95.6 87.1 72.8 65.7 32.3 82.1 99.8 100 100 100 87.4 1.2 3.9 8.9 13.6 22.4 25.5 26.4 2.0 8.0 24.6 36.5 46.6 50.5 47.3 |
In (Ga) %=5%, [HZSM5]: [MxOy]=10: 2, GHSV=3600h
-1, NO=2500ppm, CH
4=2000ppm, O
2=4.0%, He is a balance gas, catalyst-assembly 1.0ml, and reaction pressure is a normal pressure.
The content of embodiment 4 iron oxide is to In/HZSM5+Fe
2O
3The influence of the reactivity of catalyst
| Catalyst | Reaction temperature (℃) |
| 350 400 450 500 550 600 650 | |
| In/HZSM5 In/HZSM5+Fe 2O 3(10∶0.5) *In/HZSM5+Fe 2O 3(10∶2) In/HZSM5+Fe 2O 3(10∶4) In/HZSM5+Fe 2O 3(10∶6) In/HZSM5+Fe 2O 3(10∶8) In/HZSM5+Fe 2O 3(10∶10) | 25.1 70.2 95.8 100 99.6 93.4 76.4 24.4 78.2 100 100 100 97.4 84.9 32.3 82.1 99.8 100 100 100 87.4 29.3 74.2 95.0 100 100 94.0 76.4 18.9 59.6 90.1 100 100 94.0 76.4 16.5 63.0 94.0 100 100 92.6 72.8 17.6 57.6 89.0 100 100 83.3 64.3 |
*Expression formula in the bracket is represented HZSM5 and Fe
2O
3Weight ratio.
In%=5%, GHSV=3600h
-1, NO=2500ppm, CH
4=2000ppm, O
2=4.0%, He is a balance gas, catalyst-assembly 1.0ml, and reaction pressure is a normal pressure.
The content of embodiment 5 indium metal is to In/HZSM5+Fe
2O
3The influence of the reactivity of (10: 2) catalyst
| Catalyst | Reaction temperature (℃) |
| 350 400 450 500 550 600 650 | |
| HZSM5+Fe 2O 3 | 2.4 12.5 16.4 17.3 15.2 14.3 9.0 |
| 5％In/HZSM5+Fe 2O 3 10％In/HZSM5+Fe 2O 3 20％In/HZSM5+Fe 2O 3 | 32.3 82.1 99.8 100 100 100 87.4 4.4 19.5 42.7 61.4 70.5 65.4 56.7 4.3 18.9 41.2 61.1 70.3 65.4 57.3 |
NO=2500ppm, CH
4=2000ppm, O
2=4.0%, He is a balance gas, catalyst-assembly 1.0ml, and reaction pressure is a normal pressure, GHSV=3600h
-1
Embodiment 6 reaction temperatures are to 5%In/HZSM5+Fe
2O
3The influence of the reactivity of (10: 2) catalyst
| Reaction temperature (℃) 400 450 500 550 600 650 NO conversion ratios (%) 82.1 99.8 100 100 100 87.4 |
NO=2500ppm, CH
4=2000ppm, O
2=4.0%, He is a balance gas, catalyst-assembly 1.0ml, and reaction pressure is a normal pressure, GHSV=3600h
-1
Embodiment 7 oxygen concentrations are to 5%In/HZSM5+Fe
2O
3The influence of the reactivity of (10: 2) catalyst
| Oxygen concentration | Reaction temperature (℃) |
| 350 400 450 500 550 600 650 | |
| 1.0％ 3.0％ 5.0％ | 30.8 69.0 86.4 89.8 88.9 85.2 72.5 30.0 71.9 89.6 94.2 95.1 94.2 81.8 27.1 77.6 92.1 96.1 97.8 94.3 82.8 |
NO=2500ppm, CH
4=2000ppm, He are balance gas, catalyst-assembly 1.0ml, and reaction pressure is a normal pressure, GHSV=3600h
-1
Embodiment 8 air speeds are to 5%In/HZSM5+Fe
2O
3The influence of the reactivity of (10: 4) catalyst
| The reacting gas air speed | Reaction temperature (℃) |
| 350 400 450 500 550 600 650 | |
| 3600h -1 7200h -1 10800h -1 | 29.3 74.2 95.0 100 100 94.0 76.4 25.2 65.8 95.6 100 100 96.9 79.4 21.5 61.7 88.7 100 100 96.1 78.3 |
NO=2500ppm, CH
4=2000ppm, O
2=4.0%, He is a balance gas, catalyst-assembly 1.0ml, and reaction pressure is a normal pressure.
Claims (2)
1. the preparation method of a methane selective reducing nitrogen oxide catalyst under oxygen-enriched condition, it is characterized in that: at first be 10: 0.5～20 iron oxide and silica alumina ratio less than 50 molecular sieve mechanical mixture with weight ratio, again the method for indium salt with dipping supported on the molecular sieve, the weight percentage that makes molecular sieve supported indium is 0.5～20%, 500～900 ℃ of sintering temperatures, 3～6 hours time.
2. a catalyst that is made by the described preparation method of claim 1 is used for the excess oxygen methane selective reducing nitrogen-oxygen compound under oxidation, is reducing agent with methane, [CH in the unstripped gas
4]/[NO] concentration ratio is 0.2～8.0, reaction temperature is between 350～650 ℃, oxygen concentration is between 2.0～10.0%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB981143369A CN1142025C (en) | 1998-09-23 | 1998-09-23 | Methane selective reducing nitrogen oxide catalyst under oxygen-enriched condition |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB981143369A CN1142025C (en) | 1998-09-23 | 1998-09-23 | Methane selective reducing nitrogen oxide catalyst under oxygen-enriched condition |
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| Publication Number | Publication Date |
|---|---|
| CN1248493A CN1248493A (en) | 2000-03-29 |
| CN1142025C true CN1142025C (en) | 2004-03-17 |
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|---|---|---|---|
| CNB981143369A Expired - Fee Related CN1142025C (en) | 1998-09-23 | 1998-09-23 | Methane selective reducing nitrogen oxide catalyst under oxygen-enriched condition |
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| CN104906611A (en) * | 2015-06-12 | 2015-09-16 | 常州大学 | Method and device for disinfecting and sterilizing plastic packaging containers |
| CN107930675B (en) * | 2016-10-13 | 2020-03-31 | 中国石油化工股份有限公司 | Catalyst for synthesis of cyclohexylbenzene and preparation method thereof |
| CN108187732B (en) * | 2017-12-12 | 2021-04-02 | 哈尔滨工业大学深圳研究生院 | Anti-sulfur and water-resistant CH4-SCR denitration catalyst and preparation method thereof |
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1998
- 1998-09-23 CN CNB981143369A patent/CN1142025C/en not_active Expired - Fee Related
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