CN103191720B - A kind of catalyst for methanation in presence of sulfur of magnesium aluminate spinel load - Google Patents

Abstract

A sulfur-resistant methanation catalyst supported by magnesium aluminum spinel, comprising: 0-20 parts (by weight) of catalyst aid (M ₁ ) _A O _B ; 5-90 parts (by weight) of catalyst active component (M ₂ ) _C O _D ; 5-90 parts by weight of support modifier (M ₃ ) _E O _F and 100 parts by weight of porous support-magnesium aluminum spinel, wherein M ₁ is Co, Ni, La and/or K ; M ₂ is Mo, W and/or V; M ₃ is Ce, Zr, Ti and/or Si.

Description

A sulfur-tolerant methanation catalyst supported on magnesium aluminum spinel

technical field

The present invention relates to a kind of sulfur-tolerant catalyst for methanation reaction, in particular, relate to a kind of effective component CO and H of synthesis gas containing acid gases such as hydrogen sulfide Conversion into _{CH Methanation} reaction catalyst, wherein The catalyst is composed of a catalyst auxiliary agent, a catalyst active component, a carrier modifying agent and a porous carrier-magnesium aluminum spinel. At the same time, the invention also relates to a preparation method of the catalyst.

Background technique

The methanation reaction refers to the process in which CO in the synthesis gas reacts with H2 under the action of a certain temperature, pressure and catalyst to form methane. Its reaction formula can be expressed as follows:

CO+3H ₂ =CH ₄ +H ₂ O (1)

CO+H ₂ O=CO ₂ +H ₂ (2)

2CO+2H ₂ =CH ₄ +CO ₂ (3)

It is generally believed that the methanation reaction of syngas is one of the best solutions for the clean utilization of coal. Syngas is mainly obtained from coal gasification or coal pyrolysis. The synthesis of methane can be achieved by contacting the catalyst. Methanation can not only reduce the greenhouse gas emissions and environmental pollution caused by the combustion of coal by traditional methods, but also greatly increase the calorific value of gas fuels.

Generally speaking, the oxide carrier of the catalyst can increase the contact area between the active components of the catalyst and the reactants, thereby increasing the yield of the product. Commonly used catalyst supports include oxide supports such as alumina, silica, magnesia, and titanium oxide. These oxide supports have the characteristics of significantly improving the catalytic activity of the catalyst, but different supports have different effects on different reactions, and the oxide support of the catalyst The different forms of action of different catalyst metal components will directly lead to completely different effects on catalyst performance.

For the methanation reaction, for a long time, the research direction of many scholars is to try to find out the methanation catalyst and its support which have high selectivity to methane and high conversion rate to carbon monoxide. Among the existing industrial methanation catalysts, the better effect is the supported NiO catalyst, however NiO catalyst is very sensitive to surface area carbon and sulfur species, which will lead to catalyst deactivation and poisoning, when using NiO catalyst, the synthesis gas must be removed The acid gas such as H ₂ S contained in the raw material is kept below 1 ppm, which undoubtedly greatly increases the process cost of using the NiO catalyst. Therefore, it is particularly important to find other sulfur-tolerant methanation catalysts with better effects.

US4151191 discloses a method for producing _CH4 or _CH4 -containing gas from a gas mixture containing _H2 , CO and sulfide gas, wherein the methanation catalyst used includes: lanthanide and/or actinide metal oxides and Mo metal Oxides in which the atomic ratio of lanthanide and/or actinide metal to Mo is 9:1. The catalyst exhibits extremely superior methanation catalytic properties under the conditions of H ₂ /CO ratio of 1:1 and sulfide content up to 3%.

US4320030 discloses a catalyst especially suitable for methanation reaction, the catalyst comprises: a compound mixture containing Mo, V, and/or W, or a compound mixture of two or more of Mo, V, and W. The preparation method of the catalyst is as follows: first mix its active components and component precursors such as stabilizers with solid sulfur or sulfide, then roast and cool the solid in an _inert atmosphere or H2S/ _H2 atmosphere, Finally, the catalyst is passivated with a dilute oxygen-containing stream and subjected to crushing, grinding and pelletizing to finally form the desired catalyst.

US4833112 discloses a method for producing methane with a sulfur-resistant catalyst, wherein the sulfur-resistant catalyst includes metals selected from Mo, V, or W and Co and/or Ni, and the catalyst is deposited _on CeO Carriers, Mo and Ce The atomic ratio is 1/20-1/7, the BET specific surface area of the supported catalyst is 50 cm ² /g, and the pore volume is 0.15-0.5 cm ³ /g. The test shows that the Mo-based catalyst supported by CeO ₂ is effective in methanation The catalytic activity and methane selectivity are much better than those of Mo-based catalysts supported by Al ₂ O ₃ .

US4260553 discloses a three-component catalyst and its preparation method, wherein the three components are respectively a mixture of oxides and sulfides of lanthanide elements, a mixture of oxides and sulfides of Mo metal, and an alumina or silica carrier , the atomic ratio of the lanthanides, such as Ce and Mo metal, is 9/1, and the weight of the aluminum oxide or silicon oxide carrier accounts for 1%-10% of the total weight of the catalyst; the catalyst is made of lanthanides and other components Add nitrate and ammonium molybdate into the same container, then add Al ₂ O ₃ carrier, heat, dry, and roast to obtain the final catalyst. The results show that the catalyst has been improved in terms of carbon monoxide conversion and methane selectivity. , and has a certain resistance to sulfur.

However, the catalytic performance of the sulfur-resistant methanation reaction catalyst disclosed in the above-mentioned patent documents is poor in high-temperature stability, and its catalytic performance often deteriorates rapidly after the catalyst is used at high temperature for a short period of time.

At the same time, from the point of view of selecting an industrial catalyst, in addition to considering the catalytic activity of the catalyst and the selectivity of the product, factors such as the stability of the catalyst reaction, the production cost of the catalyst and the yield of the product should also be considered, so that the catalyst can be used in Commercial competitiveness in industrial production. Although the catalysts disclosed in the above patent documents have certain improvements in terms of carbon monoxide conversion rate and methane selectivity compared to traditional catalysts, they have deficiencies in reaction stability. Decrease, which will lead to shortened catalyst life, meanwhile, the production raw materials of the above-mentioned catalysts, such as CeO ₂ are expensive, so they cannot achieve a good balance and consideration between performance and production cost.

All of the aforementioned documents are hereby incorporated by reference in their entirety.

In summary, there is still a need to develop a cheap, efficient, and sulfur-tolerant methanation catalyst, which can not only improve the conversion rate of reactants and methane selectivity, but also improve the reaction stability and high-temperature catalytic performance stability. It can also reduce the production cost of the catalyst.

Contents of the invention

The inventor finally found a novel methanation catalyst that can achieve the above-mentioned purpose through numerous tests and attempts, and the experiments proved that the high-temperature catalytic performance of the catalyst is extremely stable.

According to a first aspect of the present invention, there is provided a magnesium-aluminum spinel-supported sulfur-resistant methanation catalyst, which includes: 0-20 parts (by weight) catalyst promoter ( _{M 1} ) _AOB ; 5-90 parts ( Weight) catalyst active component (M ₂ ) _{CO D ;} 5-90 parts (weight) support modifier (M ₃ ) _E O _F and 100 parts (weight) porous carrier-magnesium aluminum spinel, wherein M ₁ is Co, Ni, La and/or K; _M2 is Mo, W and/or V _; M3 is Ce, Zr, Ti and/or Si.

Preferably, M1 is further Co and/or La _{; M2} is further Mo and/or W; M3 is further Ce and/or Zr, more preferably, by weight, the sulfur _- tolerant methanation catalyst comprises: 3-10 parts of CoO; 10-40 parts of MoO ₃ ; 20-60 parts of CeO ₂ ; 100 parts of magnesium aluminum spinel, especially preferably, by weight, the sulfur-tolerant methanation catalyst includes: 5 parts of CoO; 15 parts 30-50 parts of CeO ₂ ; 100 parts of magnesium aluminum spinel, most preferably, by weight, the sulfur-resistant methanation catalyst includes: 5 parts of CoO; 15 parts of MoO _{3 ;} 33 parts of CeO ₂ ; 100 parts magnesium aluminum spinel.

According to a second aspect of the present invention, there is provided a magnesium-aluminum spinel-supported sulfur-resistant methanation catalyst, which includes: 0-20 parts (by weight) catalyst promoter ( _{M 1} ) _AOB ; 5-90 parts ( weight) catalyst active component (M _{2 ) CO D and} 100 parts (weight) porous carrier-magnesia aluminum spinel; wherein M ₁ is Co, Ni, La and/or K; M ₂ is Mo, W and/ or V.

Preferably, in the above-mentioned sulfur-tolerant methanation catalyst, M1 is further Co and or /La; _M2 is further Mo and/or W, more preferably, by weight, the above-mentioned sulfur-tolerant methanation catalyst comprises: 3-10 Parts of CoO; 10-40 parts of MoO ₃ ; 100 parts of magnesium aluminum spinel, particularly preferably, by weight, the above-mentioned sulfur-resistant methanation catalyst includes: 5 parts of CoO; 15 parts of MoO ₃ ; 100 parts of magnesium aluminum spinel .

In the first and second aspects of the present invention, the components (M ₁ ) _AOB and ( _{M 2} ) COD in the sulfur _- tolerant _methanation catalyst may optionally be at least partially or completely sulfurized by M ₁ Compounds and _M2 sulfides are substituted.

According to a third aspect of the present invention, a method for preparing the above-mentioned sulfur-resistant methanation catalyst is provided, which comprises the following steps in sequence:

(1) Prepared from the precursor of support modifier ( _{M 3} ) _EOF and/or porous support-magnesium aluminum spinel by co-precipitation method, deposition precipitation method, impregnation method, kneading method or sol-gel method ( _{M 3} ) _Porous carrier composited by EOF and magnesium aluminum spinel;

(2) _Loading the precursor composite solution of catalyst promoter ( _{M 1} ) _AOB and catalyst active component (M ₂ ) _COD on the above porous carrier by impregnation method or deposition method;

(3) Calcination drying and impregnation or deposition of (M ₁ ) _AOB and ( _{M 2} ) _COD at or above the precursor _{decomposition} temperature of ( _{M 1} ) _AOB and ( _{M 2} ) _COD The final porous carrier is obtained to obtain the above-mentioned magnesium-aluminum spinel-supported sulfur-tolerant methanation catalyst, wherein the steps of impregnating, drying and calcining are optionally repeated several times.

Preferably, the above-mentioned precursor solutions are M ₁ -M ₃ nitrate solutions, chloride salt solutions, oxalate solutions, formate solutions, acetate solutions, or their ammonium salt solutions.

Preferably, the precursor of the above-mentioned magnesium aluminum spinel is a salt solution, oxide or/and hydroxide of Mg and Al.

Generally, the specific surface area, pore structure, and pore size of the porous carrier and/or final catalyst are controlled by controlling the calcination temperature and calcination time.

Detailed ways

The present invention is further explained in detail by the following descriptions with reference to the embodiments, but the following descriptions including the embodiments are only used to enable those of ordinary skill in the art to which the present invention belongs to understand the principle and essence of the present invention more clearly, and do not mean that the present invention Limitation of any kind.

The carrier of the sulfur-resistant methanation catalyst of the present invention is aluminum-magnesium oxide with a spinel structure, and the stable oxygen tetrahedron and octahedral structure make it exhibit excellent reaction inertness. Compared with magnesium-aluminum spinel (MgAl ₂ O ₄ ), Al ³⁺ is located in the cavities of the west body, and Mg ²⁺ is located in the cavities of the octahedron. This configuration of the structure makes the Al-Mg spinel have high strength, excellent high temperature stability and excellent water resistance.

It is well known that sulfur-tolerant Mo, W and/or V-based methanation catalysts have poor high-temperature stability, mainly due to the fact that their catalytically active phase (metal sulfide) is easily sublimated and/or oxidized at high temperatures, so that its catalytically active phase or loss or be oxidized to become a non-catalytically active phase. The process can be represented by the following reaction:

(M ₁ ) _A O _B (catalytic promoter)+H ₂ S<=>M ₁ S (catalytic promoter active phase)+H ₂ O (4)

(M ₂ ) _C O _D (active component)+H ₂ S<=>M ₂ S ₂ (catalytically active phase)+H ₂ O (5)

(M ₁ ) _A O _B (catalytic promoter)+CS<=>M ₁ S (catalytic promoter active phase)+CO ₂ (6)

(M ₂ ) _C O _D (active component)+CS<=>M ₂ S ₂ (catalytically active phase)+CO ₂ (7)

Before the catalytic reaction, once the catalyst is activated by H ₂ S, (M ₁ ) _A O _B (catalytic promoter) will become M ₁ S (catalytic promoter active phase); and (M ₂ ) _{CO D} ( Active component) will become M ₂ S ₂ (catalytic active phase), therefore, when the catalytic reaction is in progress, it is M ₁ S (catalytic promoter active phase) and M ₂ S ₂ (catalytic activity phase), but the above reaction is a reversible reaction. Under certain conditions, such as high temperature and excess water and CO ₂ , the above reaction can proceed towards the direction of oxide formation. In this way, M ₁ S (catalyst promoter active phase ) and M ₂ S ₂ (catalytically active phase) will become oxides again and lose their catalytic performance. This is an important factor leading to the deterioration of the high-temperature stability of the above-mentioned sulfur-tolerant methanation catalysts.

Different from the above-mentioned sulfur-tolerant methanation catalyst, the non-sulfur-tolerant NiO methanation catalyst has a catalytically active phase of metallic nickel, and the activation process can be represented by the following reaction:

NiO+H ₂ <=>Ni (catalytically active phase)+H ₂ O (8)

Therefore, before the catalytic reaction, once the NiO catalyst is activated by H ₂ , NiO will turn into metallic Ni, and when the syngas contains excess H ₂ S and other acidic gases (higher than 1ppm), the catalytically active phase metallic nickel will occur The following response:

Ni (catalytically active phase)+H ₂ S=NiS+H ₂ (9)

At the same time, the metal surface characteristics of the catalytically active phase Ni make it very easy to generate carbon deposition on the surface, thereby blocking the contact between the catalyst surface and the synthesis gas, so that the NiO catalyst will become deactivated.

At high temperature, the reaction rate of the above reaction (9) will be accelerated, and the carbon deposition rate on the catalyst surface will also be accelerated, which is an important reason for the poor stability of NiO-based catalysts at high temperatures.

If the entry point to solve the poor high temperature stability of NiO-based catalysts is to reduce the concentration of acid gases such as H ₂ S in the synthesis gas and prevent severe carbon deposition on the surface of the catalyst, the solution to the high temperature resistance of sulfur-resistant Mo, W and/or V-based methanation catalysts The starting point of poor stability is how to prevent the above-mentioned M ₁ S (catalytic assistant active phase) and M ₂ S ₂ (catalytic active phase) from sublimating and being oxidized at high temperature.

The present inventors surprisingly found that: when Al-Mg spinel is used as the carrier of the above-mentioned sulfur-resistant Mo, W and/or V-based methanation catalyst, the active component Mo, W and/or V oxides in the catalyst The interaction with the carrier aluminum-magnesium spinel is significantly strengthened, so that the oxidation resistance of each component of the entire catalyst is also significantly enhanced, and finally the above-mentioned M ₁ S (catalytic promoter active phase) and M ₂ S ₂ (catalytic The high temperature stability of the active phase) improves the high temperature stability of the above-mentioned sulfur-resistant Mo, W and/or V-based methanation catalysts.

In fact, the sulfur-tolerant methanation catalyst supported on aluminum-magnesium spinel of the present invention is a four-component or three-component catalyst, which may include a catalyst promoter (M ₁ ) _{A OB} , a catalyst active component (M ₂ ) _{C OD} , support modifier (M ₃ ) _E O _F , and porous support-alumina-magnesium spinel, in which, the catalyst promoter is used to improve the performance of the catalyst active component, and the support modifier is used to improve the porous support The synergistic effect of the above-mentioned four components or three components makes the performance of the final catalyst significantly improved while the production cost is greatly reduced.

The sulfur-tolerant methanation catalyst of the present invention can be used to convert synthesis gas including H ₂ , CO and gaseous sulfides with a concentration not higher than 5% by volume into methane. The operating temperature of the above-mentioned methanation reaction is usually 290-650°C, preferably 450-600°C; the H ₂ /CO molar ratio is preferably 4/1-0.5/1; the reaction operating pressure is preferably 0.5-8.0 MPa, more preferably 2.0-6.0 MPa.

As mentioned above, the sulfur-tolerant methanation catalyst of the present invention includes a composite porous carrier of aluminum-magnesium spinel and a carrier modifier-which can be prepared by coprecipitation method, deposition precipitation method, impregnation method, kneading method or sol-gel method; and finally The sulfur-tolerant methanation catalyst supported by aluminum-magnesium spinel can be prepared by impregnating the above-mentioned composite porous carrier with the mixed solution of the precursor of the catalyst aid and the catalyst active component.

As an exemplary, non-limiting example of the above-mentioned porous carrier preparation method is as follows:

A: Composite porous carrier prepared by co-precipitation method:

First, a certain amount of (M ₃ ) _I (NO ₃ ) _J , such as Ce(NO ₃ ) ₃ solution, is mixed with Al-Mg spinel precursor solution, such as Al(NO ₃ ) ₃ solution and Mg(NO ₃ ) ₂ by Proportional mixing to form a mixed solution;

Then slowly add ammonia water dropwise to the mixed solution until the precipitation is complete, or flow the mixed solution and ammonia water into the precipitation tank in parallel, and keep the pH value between 6-11.5;

Next, the solution was aged for 2 hours, filtered, washed with deionized water, and dried in an oven;

Finally, calcining at 500-900° C. for 1-10 hours in a muffle furnace to obtain (M ₃ ) _E O _F /aluminum-magnesium spinel composite porous carrier.

B: Preparation of composite porous carrier by deposition precipitation method:

A certain amount of commercially available Al-Mg spinel is added in proportion to a certain concentration of (M ₃ ) _I (NO ₃ ) _J , such as Ce(NO ₃ ) ₃ solution, and then ammonia water is slowly added dropwise to the solution to (M ₃ ) _I (NO ₃ ) _J complete precipitation, and keep the pH value between 5-10;

Next, after standing and aging the solution for 2 hours, filter, wash with deionized water, and dry;

Finally, calcining at 500-900° C. for 1-10 hours in a muffle furnace to obtain (M ₃ ) _E O _F /aluminum-magnesium spinel composite porous carrier.

C: preparation of composite porous carrier by impregnation method:

Adding a certain amount of commercially available Al-Mg spinel in proportion to an appropriate amount of (M ₃ ) _I (NO ₃ ) _J , such as Ce(NO ₃ ) ₃ solution;

Then, after the solution was left to age for 2 hours, it was transferred to an oven for drying;

Finally, calcining at 500-900° C. for 1-10 hours in a muffle furnace to obtain (M ₃ ) _E O _F /aluminum-magnesium spinel composite porous carrier.

D: Preparation of composite porous carrier by kneading method:

A certain amount of (M ₃ ) _I (NO ₃ ) _J , such as Ce(NO ₃ ) ₃ solution, is mixed with Al-Mg spinel precursor, such as pseudo-boehmite and Mg(NO ₃ ) ₂ in proportion, fully After kneading;

Then, slowly dropwise add acid or a mixture of acid and water accounting for 1-15% by weight of the above mixture in the above mixture, so that the above mixture is completely peptized;

Fully kneading, kneading, or kneading the above-mentioned completely peptized mixture until the mixture exhibits good plasticity;

Next, use an extruder to extrude the above mixture, and the shape of the formed mixture can be granular, strip, block, sheet, etc.;

Dry the above-mentioned shaped mixture in a 70-160°C oven or oven;

Finally, calcining at 500-900° C. for 1-10 hours in a muffle furnace to obtain (M ₃ ) _E O _F /aluminum-magnesium spinel composite porous carrier.

E: Preparation of composite porous carrier by sol-gel method:

Add a certain amount of commercially available (M ₃ ) _E O _F , such as CeO ₂ and MgO, into the container, and then add 1.5 mol/L dilute nitric acid solution dropwise into the container while vigorously stirring until (M ₃ ) _E O _F and MgO is fully dissolved;

After ( _{M 3} ) _EOF and MgO are fully dissolved and the solution is clarified, add hexyl aluminate, absolute ethanol, and deionized water dropwise in proportion to the container, and react in a water bath at 80-90°C 4-6 hours, thereby forming a sol;

The sol is put into a drying oven and dried at 80° C. for 5-6 hours to form a xerogel;

Then the dry gel is annealed at 300-900° C. for 3-15 hours to obtain (M ₃ ) _E O _F /aluminum-magnesium spinel composite porous carrier.

The example of the preparation method of the above-mentioned aluminum-magnesium spinel supported sulfur-resistant methanation catalyst as exemplary, but not limiting, is as follows:

F: Impregnation method (I) preparation of Al-Mg spinel-supported sulfur-tolerant methanation catalyst:

The (M ₃ ) _E O _F /alumina-magnesium spinel, such as CeO ₂ /alumina-magnesium spinel composite porous support prepared by the AD method above was impregnated in (M ₁ ) _A O _B /(M ₂ ) _{CO D} , such as CoO/MoO ₃ precursor composite solution, such as Co nitrate and Mo ammonium salt mixed solution;

Put the impregnated porous carrier into a drying oven to dry;

At or above the decomposition temperature of the above-mentioned (M ₁ ) _AOB /( _{M 2} ) _COD precursors, such as Co nitrates and Mo ammonium salts, such as 400-800 ° _C , calcined, dried and impregnated ( Porous support after M ₁ ) _A O _B /(M ₂ ) _{CO D} ;

Repeat the above steps of impregnation, drying and roasting until the required weight ratio of (M ₁ ) _A O _B /(M ₂ ) _{CO D /} (M ₃ ) _E O _F /Al-Mg spinel is obtained to obtain the above-mentioned Al-Mg Spinel-supported sulfur-tolerant methanation catalysts.

G: Preparation of Al-Mg spinel-supported sulfur-tolerant methanation catalyst by impregnation method (II):

Add (M ₃ ) _E O _F / Al-Mg spinel, such as CeO ₂ / Al-Mg spinel composite porous carrier powder prepared by the above-mentioned AE method to (M ₁ ) _A O _B /(M ₂ ) _C O _D , such as CoO/MoO ₃ precursor composite solution, such as Co nitrate and Mo ammonium salt mixed solution, and vigorously stirred to form a uniform suspension;

After the formed suspension is evaporated to dryness, it is placed in a drying oven for drying, thereby removing the moisture in the suspension;

At or above the decomposition temperature of the precursors of (M ₁ ) _AOB /( _{M 2} ) _COD , such as Co nitrates and Mo ammonium salts, such as 400-800 ° _C , calcined, dried and deposited ( M ₁ ) _{A OB} /(M ₂ ) _{CO D} porous carrier to obtain the above-mentioned sulfur-resistant methanation catalyst supported by aluminum-magnesium spinel.

H: Preparation of aluminum-magnesium spinel-supported sulfur-tolerant methanation catalysts by deposition-precipitation method:

Add (M ₃ ) _E O _F / Al-Mg spinel, such as CeO ₂ / Al-Mg spinel composite porous carrier powder prepared by the AD method above to (M ₁ ) _A O _B /(M ₂ ) _{CO D ,} such as CoO/MoO ₃ precursor composite solution, such as Co nitrate and Mo ammonium salt mixed solution, and then adjust the pH value of the solution by adding nitric acid or ammonia water to form a precipitate;

Next, after standing and aging the solution for 2 hours, filter, wash with deionized water, and dry;

The porous carrier on which (M ₁ ) _AOB /( _{M 2} ) _CO is deposited is put into a drying oven to dry;

The precursors of (M ₁ ) _AOB /( _{M 2} ) COD, such as _Co nitrates and Mo ammonium salts, are decomposed at or above the decomposition temperature, such as 400-800° _C for calcination, drying and precipitation (M ₁ ) _A O _B /(M ₂ ) _CO porous carrier to obtain the above-mentioned sulfur-resistant methanation catalyst supported by aluminum-magnesium spinel.

Example

The ratios of materials in the following examples are weight ratios unless otherwise specified.

Embodiment 1: Preparation of 15MoO ₃ /100 Al-Mg spinel (0.91Al ₂ O ₃ /0.09MgO) catalyst

Step (1): Preparation of 91Al ₂ O ₃ -9MgO aluminum-magnesium spinel porous support by co-precipitation method

311.4 grams of Al(NO ₃ ) ₃ 9H ₂ O and 32.1 grams of Mg(NO ₃ ) ₃ 6H ₂ O were dissolved in 500 milliliters of deionized water to form a mixed solution, and the mixed solution was mixed with a concentration of 3 mol/liter Ammonia water was poured into the beaker under vigorous stirring at 70°C, keeping the pH value at about 11. After the reaction was complete and the precipitation was complete, it was allowed to stand and age for 2 hours. The precipitate was filtered, washed three times with deionized water, and the obtained filter cake was put into Dry in an oven at 120°C for 12 hours to obtain a dry powder. The above dry powder was calcined in a muffle furnace at 700°C for 2 hours to obtain a 91Al ₂ O ₃ /9MgO aluminum-magnesium spinel porous carrier with a BET specific surface area of 235m ² /g. Step (2): Preparation of 15MoO ₃ /100 Al-Mg spinel (0.91Al ₂ O ₃ /0.09MgO) catalyst

Dissolve 5.58 grams of (NH ₄ ) ₆ Mo ₇ O ₂₄ ·4H ₂ O in 50 ml of deionized water to form a solution, weigh 30 grams of the above-mentioned aluminum-magnesium spinel porous carrier powder, add it to the above solution, stir vigorously, and evaporate to dryness , put it in a drying oven at 120°C for 12 hours, and finally bake it in a muffle furnace at 750°C for 2 hours to obtain 15MoO ₃ /100 Al-Mg spinel (0.91Al ₂ O ₃ /0.09MgO) resistant to sulfur methanation The catalyst has a BET specific surface area of 206 m ² /g.

Comparative Example 1: Preparation of 15MoO ₃ /100Al ₂ O ₃ Methanation Catalyst

Dissolve 5.58 g (NH ₄ ) ₆ Mo ₇ O ₂₄ ·4H ₂ O in 50 ml of deionized water to form a solution, weigh 30 g of alumina powder (commercial Sasol product, specific surface area is 200 m ² /g), and then Add the aluminum powder into the above solution and stir vigorously, evaporate the water to dryness, put it in a drying oven at 120°C for 12 hours, and finally bake it in a muffle furnace at 750°C for 2 hours to obtain 15MoO ₃ /100Al ₂ O ₃ sulfur-resistant methane The catalyst has a BET specific surface area of 174 m ² /g.

Embodiment 2: Preparation of 15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

Step (1): Preparation of 83Al ₂ O ₃ -17MgO Al-Mg spinel porous support by co-precipitation method

Except that the amount of Mg(NO ₃ ) ₃ 6H ₂ O was changed from 32.1 g to 64.2 g, the step (1) in Example 1 was repeated to obtain 83Al ₂ O ₃ -17MgO alumina-magnesium spinel porous support, which The specific surface area measured by BET was 213m ² /g.

Step (2): Preparation of 15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

Step (2) in Example 1 was repeated to obtain a 15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) sulfur-tolerant methanation catalyst with a BET specific surface area of 197m ² /g.

Comparative Example 2: Preparation of 15MoO ₃ /100CeO ₂ methanation catalyst

Except changing Al ₂ O ₃ powder into CeO ₂ powder (specific surface area is 45m ² /g), repeat the steps in Comparative Example 1, obtain 15MoO ₃ /100CeO ₂ Sulfur-resistant methanation catalyst, its BET measurement specific surface area is 28m ² /g.

Embodiment 3: Preparation of 15MoO ₃ /100 Al-Mg spinel (0.8Al ₂ O ₃ /0.2MgO) catalyst

Except that the weight of Mg(NO ₃ ) ₃ ·6H ₂ O in Example 1 was increased from 32.1 grams to 80.3 grams, the steps in Example 1 were repeated to obtain 15MoO ₃ /100 Al-Mg spinel (0.8Al ₂ O ₃ /0.2MgO) sulfur-resistant methanation catalyst, its BET specific surface area is 197m ² /g.

Embodiment 4: Preparation of 15MoO ₃ /100 Al-Mg spinel (0.74Al ₂ O ₃ /0.26MgO) catalyst

Except that the weight of Mg(NO ₃ ) ₃ ·6H ₂ O in Example 1 was increased from 32.1 grams to 112.4 grams, the steps in Example 1 were repeated to obtain 15MoO ₃ /100 Al-Mg spinel (0.74Al ₂ O ₃ /0.26MgO) sulfur-resistant methanation catalyst, its specific surface area measured by BET is 190m ² /g.

Embodiment 5: Preparation of 15MoO ₃ /100 Al-Mg spinel (0.71Al ₂ O ₃ /0.29MgO) catalyst

Except that the weight of Mg(NO ₃ ) ₃ ·6H ₂ O in Example 1 was increased from 32.1 g to 128.4 g, the steps in Example 1 were repeated to obtain 15MoO ₃ /100 Al-Mg spinel (0.71Al ₂ O ₃ /0.29MgO) sulfur-tolerant methanation catalyst, its specific surface area measured by BET is 174m ² /g.

Embodiment 6: 15MoO ₃ /100 Al-Mg spinel (0.65Al ₂ O ₃ /0.35MgO) catalyst

Except that the weight of Mg(NO ₃ ) ₃ ·6H ₂ O in Example 1 was increased from 32.1 grams to 173.7 grams, the steps in Example 1 were repeated to obtain 15MoO ₃ /100 Al-Mg spinel (0.65Al ₂ O ₃ /0.35MgO) sulfur-tolerant methanation catalyst, its specific surface area measured by BET is 167m ² /g.

test case 1

The catalytic activity and stability, CO conversion rate and _CH4 selectivity of the methanation catalysts prepared in Examples 1-6 and Comparative Examples 1-2 were tested.

The test conditions are: the reaction is carried out in a fixed-bed reactor, the composition of syngas feedstock (volume%): 45CO; 45H ₂ ; 19.8N ₂ ; 0.2H ₂ S, the space velocity of syngas feedstock (GHSV): 5000h ^-1 Pressure: 3.0MPa, reaction temperature: 650°C.

Table 1 below shows the results of CO conversion and _CH4 selectivity of the above-mentioned various catalysts under the above-mentioned reaction conditions after 2 hours of reaction and 30 hours of reaction respectively.

Table 1

It can be seen from Table 1 that the sulfur-resistant methanation catalyst supported by aluminum-magnesium spinel of the present invention (Example 1-6) has higher activity and High temperature stability has two notable features.

Example 7: Preparation of 15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

Step (1): Preparation of 83Al ₂ O ₃ -17MgO Al-Mg spinel porous support by impregnation method

53.8 g of Mg(NO ₃ ) ₃ ·6H ₂ O was dissolved in 80 ml of deionized water to form a solution. Weigh 42 grams of alumina powder (commercial Sasol product, with a specific surface area of 200m ² /g), then add the alumina powder to the above solution and stir vigorously, evaporate the water to dryness, and then put it in a drying oven at 110°C for 16 hours , and finally calcined in a muffle furnace at 700°C for 2 hours to obtain a porous carrier of 83Al ₂ O ₃ /17MgO aluminum-magnesium spinel with a BET specific surface area of 175m ² /g.

Step (2): Preparation of 15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

The process of step (2) in Example 1 was repeated to obtain a 15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) sulfur-tolerant methanation catalyst with a BET specific surface area of 157m ² /g.

Example 8: Preparation of 15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

Step (1): Preparation of 83Al ₂ O ₃ -17MgO Al-Mg spinel porous support by kneading method

Weigh 300 grams of pseudo-boehmite (Al ₂ O ₃ : 70% by weight) and put it into a kneader, then add 269 grams of Mg(NO ₃ ) ₃ 6H ₂ O and 90 milliliters of deionized water in turn, and mix well Finally, add an acidic peptizer such as nitric acid, hydrochloric acid, glacial acetic acid and/or citric acid to fully peptize the mixture, then knead or knead until the mixture shows good plasticity, and then put the mixture into a column The extruder is formed in the orifice plate, and the mixture is extruded into a wet strip. After drying the wet strip at 120°C, it was calcined at 700°C for 5 hours in an air atmosphere to obtain a columnar alumina-magnesium spinel porous carrier. The composition of the porous carrier is: 83Al ₂ O ₃ /17MgO, and its BET specific surface area is 206m ² / g.

Step (2): Preparation of 15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

The process of step (2) in Example 1 was repeated to obtain a 15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) sulfur-resistant methanation catalyst with a BET specific surface area of 191 m ² /g.

Example 9: Preparation of 15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

Step (1): Preparation of 83Al ₂ O ₃ -17MgO Al-Mg spinel porous support by sol-gel method

311.4 g of Al(NO ₃ ) ₃ ·9H ₂ O and 64.2 g of Mg(NO ₃ ) ₃ ·6H ₂ O were dissolved in 350 ml of deionized water to form a mixed solution. Weighed 252.2 g of citric acid (C ₆ H ₈ O ₇ ·1H ₂ O) and added it to the above solution, stirred vigorously to dissolve it, put it in a water bath at 80° C., and evaporated to dryness to obtain a transparent gel. The gel was dried in an oven at 120° C. for 20 hours to obtain a dry powder. The above dry powder was calcined at 700°C for 2 hours to obtain a porous carrier of 83Al ₂ O ₃ /17MgO Al-MgS spinel with a BET specific surface area of 245 m ² /g. .

Step (2): Preparation of 15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

The process of step (2) in Example 1 was repeated to obtain a 15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) sulfur-resistant methanation catalyst with a BET specific surface area of 201 m ² /g.

test case 2

The catalytic activity and stability, CO conversion and _CH4 selectivity of the methanation catalysts prepared in Examples 7-9 were tested.

The test conditions of this test case are exactly the same as those of test case 1. The test results are shown in Table 2 below

Table 2

As can be seen from Table 2: no matter what method is used to prepare the sulfur-resistant methanation catalyst supported by Al-Mg spinel of the present invention, the final catalytic activity and high temperature stability are very good, wherein the Al-Mg spinel porous carrier The sulfur-resistant methanation catalyst of the present invention prepared by the sol-gel method has the best performance.

Example 10: Preparation of 2CoO/15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

Step (1): Preparation of 83Al ₂ O ₃ -17MgO Al-Mg spinel porous support by co-precipitation method

The process of step (1) in Example 2 was repeated to obtain a porous carrier of 83Al ₂ O ₃ -17MgO aluminum-magnesium spinel with a specific surface area of 213 m ² /g as measured by BET.

Step (2): Preparation of 2CoO/15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

Dissolve 42.5 g of (NH ₄ ) ₆ Mo ₇ O24·4H ₂ O and 17.9 g of Co(NO ₃ ) ₂ ·6H ₂ O in 250 ml of deionized water to form a mixed solution, and then mix the 228.5 grams of 83Al ₂ O ₃ /17MgO aluminum-magnesium spinel porous carrier powder was added to the mixed solution and stirred vigorously to form a uniform suspension, evaporated to dryness, and then dried in a 110°C drying oven for 16 hours. Finally, it was calcined in a muffle furnace at 750°C for 2 hours to obtain a 2CoO/15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) sulfur-resistant methanation catalyst with a BET specific surface area of 189m ² /g .

Example 11: Preparation of 5CoO/15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

Step (1): Preparation of 83Al ₂ O ₃ -17MgO Al-Mg spinel porous support by co-precipitation method

The process of step (1) in Example 2 was repeated to obtain a porous carrier of 83Al ₂ O ₃ -17MgO aluminum-magnesium spinel with a specific surface area of 213 m ² /g as measured by BET.

Step (2): Preparation of 5CoO/15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

Except that the amount of Co(NO ₃ ) ₂ 6H ₂ O was changed from 17.9 grams to 43.8 grams, the process of step (2) in Example 10 was repeated to obtain 5CoO/15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) sulfur-resistant methanation catalyst, its specific surface area measured by BET is 185m ² /g.

Example 12: Preparation of 5NiO/15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

Step (1): Preparation of 83Al ₂ O ₃ -17MgO Al-Mg spinel porous support by co-precipitation method

The process of step (1) in Example 2 was repeated to obtain a porous carrier of 83Al ₂ O ₃ -17MgO aluminum-magnesium spinel with a specific surface area of 213 m ² /g as measured by BET.

Step (2): Preparation of 5NiO/15MoO ₃ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

Except changing 17.9 g of Co(NO ₃ ) ₂ ·6H ₂ O to 18.0 g of Ni(NO ₃ ) ₂ ·6H ₂ O, repeat the process of step (2) in Example 10 to obtain 5NiO/15MoO ₃ /100 Al Magnesium spinel (0.83Al ₂ O ₃ /0.17MgO) sulfur-resistant methanation catalyst, its BET specific surface area is 187m ² /g

Test case 3

The catalytic activity and stability, CO conversion rate and CH ₄ selectivity of the sulfur-tolerant methanation catalysts of the present invention prepared in Examples 10-12 above were tested.

Test conditions: the same conditions as in Test Example 1.

Table 3 below shows the results of CO conversion and _CH4 selectivity of the above catalysts under the above conditions after 2 hours of reaction and 30 hours of reaction respectively.

table 3

It can be seen from Table 3 that adding catalyst promoters CoO and NiO can significantly improve the catalytic activity and high-temperature catalytic performance stability of the sulfur-tolerant methanation catalyst supported by aluminum-magnesium spinel of the present invention.

Example 13: Preparation of 15MoO ₃ /9ZrO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst Step (1): Prepare 9ZrO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) composite porous support

In addition to adding 11.8 grams of ZrO(NO ₃ ) ₂ ·2H ₂ O, repeat the process of step (1) in Example 2 to obtain a composite of 9ZrO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) The porous carrier has a BET specific surface area of 191m ² /g.

Step (2): Preparation of 15MoO ₃ /9ZrO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

The process of step (2) in Example 2 was repeated to obtain a 15MoO ₃ /9ZrO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst with a BET specific surface area of 173m ² /g.

Example 14: Preparation of 15MoO ₃ /9TiO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

Step (1): Preparation of 9TiO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) composite porous support by co-precipitation method

Except that 11.8 g of ZrO(NO ₃ ) ₂ ·2H ₂ O was replaced by 12.9 g of TiCl ₄ , the process of step (1) in Example 13 was repeated to obtain 9TiO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ / 0.17MgO) composite porous carrier, its specific surface area measured by BET is 196m ² /g.

Step (2): Preparation of 15MoO ₃ /9TiO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

The process of step (2) in Example 2 was repeated to obtain a 15MoO ₃ /9TiO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst with a BET specific surface area of 185m ² /g.

Example 15: Preparation of 15MoO ₃ /9CeO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

Step (1): Preparation of 9CeO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) composite porous support by coprecipitation method

In addition to adding 13.7 grams of Ce(NO ₃ ) ₃ 6H ₂ O, repeat the process of step (1) in Example 2 to obtain 9CeO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) composite The porous carrier has a BET specific surface area of 186m ² /g.

Step (2): Preparation of 15MoO ₃ /9CeO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst

The process of step (2) in Example 2 was repeated to obtain a 15MoO ₃ /9CeO ₂ /100 Al-Mg spinel (0.83Al ₂ O ₃ /0.17MgO) catalyst with a BET specific surface area of 170m ² /g.

Test case 4

The catalytic activity and stability, CO conversion rate and CH ₄ selectivity of the sulfur-tolerant methanation catalysts of the present invention prepared in Examples 13-15 above were tested.

Test conditions: the same conditions as in Test Example 1.

Table 4 below shows the results of CO conversion and _CH4 selectivity of the above catalysts under the above conditions after 2 hours of reaction and 30 hours of reaction respectively.

Table 4

It can be seen from Table 4 that adding support modifiers ZrO ₂ , TiO ₂ and CeO ₂ can also significantly improve the catalytic activity and high-temperature catalytic performance stability of the sulfur-tolerant methanation catalyst supported on Al-Mg spinel of the present invention.

Test example 5 tests the catalytic performance of the sulfur-resistant methanation catalyst supported by aluminum-magnesium spinel of the present invention under a water vapor atmosphere

The catalytic activity and stability, CO conversion and _CH4 selectivity of the methanation catalysts prepared in Examples 2 and 13 and Comparative Example 1 were tested under a water vapor atmosphere.

The test conditions are: the reaction is carried out on a fixed bed reactor, the raw material composition of syngas (volume %): 40CO; 40H ₂ ; 10H ₂ O; 19.8N _{2 ;} ^-1 , reaction pressure: 3.0MPa, reaction temperature: 650°C.

Table 5 below shows the results of CO conversion and _CH4 selectivity of the above-mentioned various catalysts under the above-mentioned reaction conditions after 2 hours of reaction and 30 hours of reaction respectively.

table 5

It can be seen from Table 5 that compared with the conventional sulfur-resistant methanation catalyst (comparative example 1), the sulfur-resistant methanation catalyst supported by aluminum-magnesium spinel of the present invention can withstand high temperature (650°C) and water vapor (10% by volume) ) atmosphere, showing excellent stability of catalytic performance.

To sum up, the sulfur-resistant methanation catalyst supported by aluminum-magnesium spinel of the present invention has extremely excellent high-temperature catalytic performance and stability, and is suitable for large-scale industrial production of synthetic natural gas.

The terms and expressions used in this specification are used only as descriptive, not restrictive terms and expressions, and when using these terms and expressions, it is not intended to exclude any equivalents of the features shown and described or their components outer.

While several embodiments of the invention have been shown and described, the invention is not limited to the described embodiments. On the contrary, those skilled in the art should realize that any modifications and improvements can be made to these embodiments without departing from the principle and spirit of the present invention, and the protection scope of the present invention is determined by the appended claims and their equivalents.

Claims (14)

1. a magnesia-aluminum spinel supported sulfur-resistant methanation catalyst, is characterized in that: described catalyst comprises: 0-20 part (weight) catalyst auxiliary agent ( _{M ) AOB} ; 5-90 part (weight ) catalyst active component (M ₂ ) _{CO D ;} 5-90 parts (weight) carrier modifier (M ₃ ) _E O _F and 100 parts (weight) porous carrier, wherein, M ₁ is Co, Ni, La and/or K; M ₂ is Mo, W and/or V; M ₃ is Ce, Zr, Ti and/or Si. 2. a supported sulfur-resistant methanation catalyst, characterized in that: said catalyst comprises: 0-20 parts (weight) catalyst aid ( _{M 1} ) _AOB ; 5-90 parts (weight) catalyst active component (M _{2 ) CO D and} 100 parts (by weight) of porous carrier-magnesium aluminum spinel; wherein, M ₁ is Co, Ni, La and/or K; M ₂ is Mo, W and/or V. 3. The sulfur-tolerant methanation catalyst according to claim 1, wherein M ₁ is further Co and/or La; M ₂ is further Mo and/or W; M ₃ is further Ce and/or Zr. 4. The sulfur-tolerant methanation catalyst according to claim 3, comprising, by weight: 3-10 parts of CoO; 10-40 parts of MoO ₃ ; 20-60 parts of CeO ₂ ; 100 parts of magnesium aluminum spinel. 5. The sulfur-tolerant methanation catalyst according to claim 4, comprising, by weight: 5 parts of CoO; 15 parts of MoO ₃ ; 30-50 parts of CeO ₂ ; 100 parts of magnesium aluminum spinel. 6. The sulfur-tolerant methanation catalyst according to claim 5, comprising, by weight: 5 parts of CoO; 15 parts of MoO ₃ ; 33 parts of CeO ₂ ; and 100 parts of magnesium aluminum spinel. 7. The sulfur-tolerant methanation catalyst according to claim 2, wherein M ₁ is further Co and/or/La; M ₂ is further Mo and/or W. 8. The sulfur-tolerant methanation catalyst according to claim 7, comprising, by weight: 3-10 parts of CoO; 10-40 parts of MoO ₃ ; and 100 parts of magnesium aluminum spinel. 9. The sulfur-tolerant methanation catalyst according to claim 8, comprising, by weight: 5 parts of CoO; 15 parts of MoO ₃ ; and 100 parts of magnesium aluminum spinel. 10. according to the sulfur-resistant methanation catalyst described in any one of claim 1-9, it is characterized in that: described component (M ₁ ) _{A OB} and (M ₂ ) _{CO D} are respectively at least partly or fully covered by M ₁ sulfide and M ₂ sulfide. 11. A preparation method according to any one of claim 1, 3-10, wherein the sulfur-resistant methanation catalyst is characterized in that: the preparation method comprises the following steps successively: (1) Prepared from the carrier modifier ( _{M 3} ) _EOF and the porous carrier-magnesium aluminum spinel precursor by coprecipitation method, deposition precipitation method, impregnation method, kneading method or sol-gel method. ₃ ) _A composite porous carrier of _EOF and magnesium aluminum spinel; (2) _supporting the composite solution of the catalyst promoter ( _{M 1} ) _AOB and the precursor of the catalyst active component (M ₂ ) _COD on the above porous carrier by impregnation or deposition; (3) Drying and impregnation or deposition of ( _{M 1} ) _AOB and/or ( _{M 2} ) by firing at or above the decomposition temperature of the precursors of ( _{M 1} ) _AOB and (M ₂ ) _COD The porous _carrier after COD is obtained to obtain the above-mentioned magnesium aluminum spinel-supported sulfur _- tolerant methanation catalyst, wherein the steps of impregnating, drying and calcining are optionally repeated several times. 12. The preparation method of sulfur-resistant methanation catalyst according to claim 11, wherein said precursor complex solution is M ₁ , M ₂ nitrate, chloride, oxalate, formate, acetate and/or their ammonium salt solutions. 13. The method for preparing a sulfur-tolerant methanation catalyst according to claim 11, wherein the precursor of the magnesium-aluminum spinel is a salt solution, oxide or/and hydroxide of Mg and Al. 14. The method for preparing a sulfur-tolerant methanation catalyst according to claim 11, wherein the specific surface area, pore structure, and pore size of the porous carrier and/or the final catalyst are controlled by controlling the calcination temperature and calcination time.