CN104475098A - Catalyst for preparing synthetic gas by partially oxidizing methane and preparation method of catalyst - Google Patents
Catalyst for preparing synthetic gas by partially oxidizing methane and preparation method of catalyst Download PDFInfo
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- CN104475098A CN104475098A CN201410763312.8A CN201410763312A CN104475098A CN 104475098 A CN104475098 A CN 104475098A CN 201410763312 A CN201410763312 A CN 201410763312A CN 104475098 A CN104475098 A CN 104475098A
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- catalyst
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- portion oxidation
- oxidation synthesis
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- Y02P20/00—Technologies relating to chemical industry
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- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
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Abstract
The invention discloses a catalyst for preparing a synthetic gas by partially oxidizing methane and a preparation method of the catalyst, and relates to nano catalysts for preparing synthetic gases. The catalyst for preparing the synthetic gas by partially oxidizing methane takes SiO2 as a carrier and CeO2 as an additive, and is prepared from the following components in percentage by mass: 0.005-1% of an active component Rh, 5-30% of an additive CeO2 and the balance of SiO2, wherein the particle size of Rh is 1-2nm and the specific surface area of Rh is 350-450m<2>/g. The preparation method comprises the following steps: 1) soaking the carrier in a nitric acid solution, washing till the pH value is 6.5-7.0 and drying for later use; 2) respectively preparing a rhodate solution and a cerate solution according to the content ratios of the components of the catalyst, and mixing the solutions into a mixed steeping liquid according to the ratios of the components of the catalyst; and 3) mixing SiO2 obtained in the step 1) with the steeping liquid obtained in the step 2), steeping, drying, and roasting, so as to obtain the catalyst for preparing the synthetic gas by partially oxidizing methane.
Description
Technical field
The present invention relates to the nanocatalyst of preparing synthetic gas, especially relate to a kind of Catalysts and its preparation method of methane portion oxidation synthesis gas.
Background technology
The main component of natural gas and shale gas is methane, and along with the large scale mining of natural gas and shale gas utilizes, effective utilization of methane more and more receives the concern of people.Utilize methane conversion to be exactly be translated into synthesis gas for one of effective way of high added value product, then utilize synthesis gas to prepare methyl alcohol, liquid fuel and other chemical products.Compared with traditional methane vapor reforming preparing synthetic gas, methane portion oxidation synthesis gas has that reactor volume is little, reaction rate is fast, energy consumption is low and the C/Hratio of product is applicable to the advantages such as follow-up methyl alcohol and Fiscber-Tropscb synthesis.Thus methane portion oxidation synthesis gas reaction receives much concern in recent years.
Methane portion oxidation synthesis gas catalyst mainly load type metal catalyst, wherein can be divided into two classes: a class is load-type nickel, Co catalysts, the easy carbon distribution of Raney nickel, active component easily runs off, and Co catalysts activity is relatively low, activity is easily oxidized mutually; Another kind of is loaded noble metal catalyst, and the type catalyst has reliable stability and excellent activity and selective, but its price is relatively costly.
Rhodium catalyst has the features such as stability is high, oxidation resistance is strong, thus shows excellent reactivity worth.1wt%Rh/SiO
2catalyst can show good catalytic activity (J.Catal.2004,226,247 – 259) at 450 DEG C.Because rhodium is expensive, preparation load capacity is low and the catalyst of stable in catalytic performance pushes this reaction to industrialized essential step.Document (ChemCatChem 2012,4,1368-1375) by reduction of ethylene glycol method synthesis particle diameter only have about 1.3nm Rh nano particle and by its load at γ-Al
2o
3on for the preparation of the catalyst of this reaction, because the decentralization of Rh is very high, when the load capacity of Rh is low to moderate 0.005wt%, still can show good catalytic activity and stability.But this method for preparing catalyst is complicated and be only applicable to the lower reaction condition of air speed.Therefore by adding suitable auxiliary agent, improving activity, the selective and stability of catalyst further, is the effective way of the consumption reducing rhodium.CeO
2there is unique redox property, can store and discharge oxygen, simultaneously CeO
2and can soluble solids be formed between Rh, prevent Rh in the migration of catalyst surface, improve the stability of catalyst.
Summary of the invention
The object of this invention is to provide a kind of Catalysts and its preparation method of methane portion oxidation synthesis gas.
The catalyst of described methane portion oxidation synthesis gas is with SiO
2for carrier, CeO
2for auxiliary agent, by mass percentage, the content of active component Rh is 0.005% ~ 1%, auxiliary agent CeO
2for 5%-30%, all the other are SiO
2; The content of preferred active component Rh is 0.01% ~ 1%, auxiliary agent CeO
2for 5%-30%, all the other are SiO
2.The particle diameter of Rh is 1 ~ 2nm, and specific area is 350 ~ 450m
2/ g.
The preparation method of the catalyst of described methane portion oxidation synthesis gas, comprises the following steps:
1) by carrier S iO
2be immersed in salpeter solution, wash to pH=6.5 ~ 7.0, for subsequent use after dry;
2) prepare the salting liquid of rhodium and the salting liquid of cerium respectively by catalyst components content proportioning, and be merged into mixed impregnant liquor according to catalyst components ratio;
3) by step 1) SiO that obtains
2with step 2) maceration extract that obtains mixes, and dipping, dries, the catalyst (Rh-CeO of obtained methane portion oxidation synthesis gas after roasting
2/ SiO
2catalyst).
In step 1) in, the condition of described immersion can be and is immersed in mass concentration is 12 ~ 24h in the salpeter solution of 20%; Described washing can adopt distilled water to wash; Dry 12h at the condition of described drying can be 110 ~ 120 DEG C;
In step 2) in, the salting liquid precursor salt used of described rhodium and cerium is acetylacetone,2,4-pentanedione rhodium and acetylacetone,2,4-pentanedione cerium, and solvent is acetylacetone,2,4-pentanedione or toluene.
In step 3) in, the time at least 12h of described immersion; The condition of described oven dry can be in 110 ~ 120 DEG C of air atmospheres dries 2h; The condition of described roasting can be: temperature is 800 DEG C, and heating rate is 1 ~ 10 DEG C/min, and atmosphere is air, and roasting time is 2 ~ 4h.
The performance evaluation that catalyst of the present invention reacts for methane portion oxidation synthesis gas is carried out on miniature fixed-bed flow reactor, internal diameter is adopted to be the quartz reactor of 6mm, K type (chromel-alumel) thermocouple for temperature control is fixed on quartz ampoule outer wall, and its thermometric end is close to the reaction tube outer wall of beds first half.Catalyst reacts after 700 DEG C of prereduction 1h in a hydrogen atmosphere.In molar ratio, the composition CH of unstripped gas
4/ O
2=2 (with or without carrier gas), unstripped gas air speed 100000h
-1, reaction pressure 0.1MPa, reaction temperature 700 ~ 800 DEG C.Catalyst uses 400h continuously, active in significant change.Described catalyst is applicable to methane and the oxygen feed gas system of wide proportioning, is applicable to inert free gas diluted system.
The present invention is a kind of take silica as carrier take ceria as high dispersive anti-sintering support type rhodium base catalyst of auxiliary agent and preparation method thereof, and for methane portion oxidation synthesis gas.The present invention selects silica to be carrier, surface hydroxyl is impelled to expose by salpeter solution clean surface residue, promote that rhodium precursor salt disperses in surface of silica support, add ceria stops rhodium at the agglomeration of the process such as roasting, reduction simultaneously, thus preparation has the Rh-CeO of high dispersive high stability
2/ SiO
2catalyst, and this catalyst is used for methane portion oxidation synthesis gas, study its catalytic performance.
The advantage of catalyst provided by the invention is: ceria stratiform spreads in silica surface, and active phase rhodium and stratiform ceria form soluble solids, overcomes rhodium and the weak shortcoming of silica surface active force; Ceria has unique redox property simultaneously, can store and discharge oxygen, thus significantly improving catalyst performance.Preparation technology of the present invention is simple, and required bullion content is extremely low, has cost advantage, and catalytic activity is high, methane conversion close to the thermodynamic equilibrium value at respective reaction temperature, to H
2high with the selection of CO, there is excellent anti-carbon performance and stability, under high-speed successive reaction 400h test period in, catalyst activity keeps stable, and post catalyst reaction surface generates without carbon distribution.
Accompanying drawing explanation
Fig. 1 is 0.5%Rh-10%CeO
2/ SiO
2catalyst 800 DEG C of roasting 2h, the transmission electron microscope picture after 700 DEG C of reduction 1h.
Detailed description of the invention
Embodiment 1
Catalyst preparing: choose 10g SiO
2as carrier, be immersed in 24h in the salpeter solution of 20%, be washed with distilled water to pH=6.5 ~ 7.0, for subsequent use after dry; Take acetylacetone,2,4-pentanedione rhodium 0.0098g to be dissolved in 20ml acetylacetone,2,4-pentanedione solution, then take acetylacetone,2,4-pentanedione cerium 0.0763g and be dissolved in 60ml acetylacetone,2,4-pentanedione, two solvents are mixed into mixed impregnant liquor, take processed good SiO
20.5g adds in mixed impregnant liquor and floods 24h, and period stirs for several times, then at 110 DEG C by solution evaporate to dryness, 800 DEG C of roasting 2h in atmosphere, heating rate is 1 DEG C/min, obtains catalyst 0.5%Rh-5%CeO
2/ SiO
2.
Appreciation condition: reaction procatalyst uses hydrogen reducing 1h at 700 DEG C.React in continuous sample introduction fixed-bed quartz reactor, reaction temperature is 700 DEG C, unstripped gas composition CH
4: O
2: Ar=2: 1: 4 (mol ratios), air speed 1 × 10
5h
-1, product uses gas-chromatography on-line analysis after condensation dewaters.Evaluation result is in table 1.
0.5%Rh-10%CeO
2/ SiO
2catalyst 800 DEG C of roasting 2h, the transmission electron microscope picture after 700 DEG C of reduction 1h is see Fig. 1.
Embodiment 2
Catalyst preparing is with reference to embodiment 1, and solvent is changed to toluene by acetylacetone,2,4-pentanedione, and all the other conditions are identical, obtain catalyst 0.5%Rh-10%CeO
2/ SiO
2appreciation condition is with embodiment 1, and evaluation result is in table 1.
Table 1
Embodiment 3 ~ 5: the quality of acetylacetone,2,4-pentanedione cerium, with reference to embodiment 1, is changed to all the other conditions of 0.1525g, 0.3050g, 0.4575g identical, obtains catalyst 0.5%Rh-10%CeO by catalyst preparing respectively
2/ SiO
2, 0.5%Rh-20%CeO
2/ SiO
2, 0.5%Rh-30%CeO
2/ SiO
2.Appreciation condition is with embodiment 1, and evaluation result is in table 2.
Table 2
Reference examples 1
Catalyst preparing, with reference to embodiment 1, takes acetylacetone,2,4-pentanedione rhodium 0.0098 and is dissolved in 20ml acetylacetone,2,4-pentanedione solution, take processed good SiO
20.5g adds in mixed impregnant liquor and floods 24h, and period stirs for several times, then at 110 DEG C by solution evaporate to dryness, 800 DEG C of roasting 2h in atmosphere, heating rate is 1 DEG C/min, obtains 0.5%Rh/SiO
2-catalyst.Appreciation condition is with embodiment 1, and evaluation result is in table 3.
Table 3
Embodiment 6 ~ 7
The quality of acetylacetone,2,4-pentanedione rhodium, with reference to embodiment 1, is changed to 0.0050g and 0.0020g, the quality of acetylacetone,2,4-pentanedione cerium is changed to 0.1525g and obtains catalyst 0.25%Rh-10%CeO by catalyst preparing respectively
2/ SiO
2and 0.1%Rh-10%CeO
2/ SiO
2all the other conditions are identical.Appreciation condition is with embodiment 1, and evaluation result is in table 4.
Table 4
Reference examples 2 ~ 3
The quality of acetylacetone,2,4-pentanedione rhodium, with reference to reference examples 1, is changed to 0.0050g and 0.0020g by catalyst preparing respectively, obtained 0.25%Rh/SiO
2and 0.1%Rh/SiO
2, all the other conditions are identical.Appreciation condition is with embodiment 1, and evaluation result is in table 5.
Table 5
Embodiment 8 ~ 9
The quality of acetylacetone,2,4-pentanedione rhodium, with reference to embodiment 1, is changed to 0.0005g and 0.0002g, the quality of acetylacetone,2,4-pentanedione cerium is changed to 0.1525g by catalyst preparing respectively, obtained catalyst 0.025%Rh-10%CeO
2/ SiO
2and 0.01%Rh-10%CeO
2/ SiO
2all the other conditions are identical.Reaction temperature is risen to 800 DEG C by 700 DEG C, and other appreciation conditions, with embodiment 1, the results are shown in Table 6.
Table 6
Embodiment 10
The quality of acetylacetone,2,4-pentanedione rhodium, with embodiment 1, is changed to 0.0050g by catalyst preparing respectively, and the quality of acetylacetone,2,4-pentanedione cerium is changed to 0.1525g, obtained catalyst 0.25%Rh-10%CeO
2/ SiO
2, by reactor feed gas composition by CH
4: O
2: Ar=2: 1: 4 (mol ratios) change CH into
4: O
2=2: 1 (without diluent gas), other appreciation conditions are with embodiment 1, and evaluation result is in table 6.
Embodiment 11
The quality of acetylacetone,2,4-pentanedione rhodium, with embodiment 1, is changed to 0.0050g by catalyst preparing respectively, and the quality of acetylacetone,2,4-pentanedione cerium is changed to 0.1525g, obtained catalyst 0.25%Rh-10%CeO
2/ SiO
2, by reactor feed gas composition by CH
4: O
2: Ar=2: 1: 4 (mol ratios) change CH into
4: O
2=2: 1 (without diluent gas), and reaction temperature is risen to 800 DEG C by 700 DEG C, other appreciation conditions are with embodiment 1, and evaluation result is in table 7.
Table 7
Embodiment 12
Catalyst preparing is with reference to embodiment 1, and the quality of acetylacetone,2,4-pentanedione rhodium is changed to 0.005g respectively, the quality of acetylacetone,2,4-pentanedione cerium is changed to 0.1525g, all the other conditions are identical, obtained catalyst 0.25%Rh-10%CeO
2/ SiO
2.Reactor feed gas consists of CH
4: O
2: Ar=2: 1: 4 (mol ratios), appreciation condition, with embodiment 1, is evaluated catalyst life, the results are shown in Table 8.
Table 8
Preparation technology of the present invention is simple, and required bullion content is extremely low, has cost advantage, and catalytic activity is high, methane conversion close to the thermodynamic equilibrium value at respective reaction temperature, to H
2high with the selection of CO, there is excellent anti-carbon performance and stability.
Claims (10)
1. a catalyst for methane portion oxidation synthesis gas, is characterized in that with SiO
2for carrier, CeO
2for auxiliary agent, by mass percentage, the content of active component Rh is 0.005% ~ 1%, auxiliary agent CeO
2for 5%-30%, all the other are SiO
2.
2. the catalyst of a kind of methane portion oxidation synthesis gas as claimed in claim 1, it is characterized in that by mass percentage, the content of active component Rh is 0.01% ~ 1%, auxiliary agent CeO
2for 5%-30%, all the other are SiO
2.
3. the preparation method of the catalyst of methane portion oxidation synthesis gas as claimed in claim 1, is characterized in that comprising the following steps:
1) by carrier S iO
2be immersed in salpeter solution, wash to pH=6.5 ~ 7.0, for subsequent use after dry;
2) prepare the salting liquid of rhodium and the salting liquid of cerium respectively by catalyst components content proportioning, and be merged into mixed impregnant liquor according to catalyst components ratio;
3) by step 1) SiO that obtains
2with step 2) maceration extract that obtains mixes, and dipping, dries, the catalyst of obtained methane portion oxidation synthesis gas after roasting.
4. the preparation method of the catalyst of methane portion oxidation synthesis gas as claimed in claim 3, its feature is in step 1) in, the condition of described immersion is that to be immersed in mass concentration be 12 ~ 24h in the salpeter solution of 20%.
5. the preparation method of the catalyst of methane portion oxidation synthesis gas as claimed in claim 3, its feature is in step 1) in, described washing adopts distilled water washing.
6. the preparation method of the catalyst of methane portion oxidation synthesis gas as claimed in claim 3, its feature is in step 1) in, the condition of described drying is dry 12h at 110 ~ 120 DEG C.
7. the preparation method of the catalyst of methane portion oxidation synthesis gas as claimed in claim 3, its feature is in step 2) in, the salting liquid precursor salt used of described rhodium and cerium is acetylacetone,2,4-pentanedione rhodium and acetylacetone,2,4-pentanedione cerium, and solvent is acetylacetone,2,4-pentanedione or toluene.
8. the preparation method of the catalyst of methane portion oxidation synthesis gas as claimed in claim 3, its feature is in step 3) in, the time at least 12h of described immersion.
9. the preparation method of the catalyst of methane portion oxidation synthesis gas as claimed in claim 3, its feature is in step 3) in, the condition of described oven dry is dry 2h in 110 ~ 120 DEG C of air atmospheres.
10. the preparation method of the catalyst of methane portion oxidation synthesis gas as claimed in claim 3, its feature is in step 3) in, the condition of described roasting is: temperature is 800 DEG C, and heating rate is 1 ~ 10 DEG C/min, atmosphere is air, and roasting time is 2 ~ 4h.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116173948A (en) * | 2022-12-08 | 2023-05-30 | 中国科学技术大学 | Rare earth oxide-silicon dioxide supported noble metal catalyst and preparation method and application thereof |
Citations (1)
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| JP2005262126A (en) * | 2004-03-19 | 2005-09-29 | Nissan Motor Co Ltd | Catalyst carrier, its preparation method and preparation method of catalyst |
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|---|---|---|---|---|
| JP2005262126A (en) * | 2004-03-19 | 2005-09-29 | Nissan Motor Co Ltd | Catalyst carrier, its preparation method and preparation method of catalyst |
Non-Patent Citations (3)
| Title |
|---|
| 严前古等: "Pt/Al2O3和Pt/CeO2/Al2O3催化甲烷部分氧化制合成气反应", 《高等学校化学学报》 * |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116173948A (en) * | 2022-12-08 | 2023-05-30 | 中国科学技术大学 | Rare earth oxide-silicon dioxide supported noble metal catalyst and preparation method and application thereof |
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