CN105289616A - Carbon dioxide methanation catalyst (Ni/CexZr(1-x)O2) and preparation method thereof - Google Patents

Abstract

The invention discloses a carbon dioxide methanation catalyst (Ni/CexZr(1-x)O2) and a preparation method thereof. The preparation method comprises the following steps: (a) adding a certain amount of nickel nitrate, a certain amount of cerium nitrate and a certain amount of zirconium nitrate into 50ml of deionized water to prepare a mixed solution with the content of Ni being 10-40wt.% in the catalyst (Ni/CexZr(1-x)O2); (b) transferring the prepared mixed solution into a thermostat water bath pan at 80 DEG C, uniformly stirring, quickly pouring a 100ml of2 mol/Lsal volatile solution into the mixed solution, stirring, heating, drying at a constant temperature, and then acquiring the powder; (c) roasting the powder after being dried for 5h in a muffle furnace by increasing the room temperature to 500 DEG C at a heating rate of 2 DEG C/min, and then putting the powder after being roasted into a steel moldfor extruding and forming, breaking and sieving, thereby acquiring the grains with the grain sizes being 40-60 meshes; and(d) reducing for 2h at the temperature being 400 DEG C in a hydrogen atmosphere, thereby acquiring the Ni/CexZr(1-x)O2 catalyst. The catalyst prepared by adopting the preparation method has relatively high catalytic activity, selectivity and stability at 250-400 DEG C. The preparation method is simple, easy to operate and low in cost.

Description

A kind of carbon dioxide methanation Ni/Ce xzr 1-xo 2catalysts and its preparation method

Technical field

The invention discloses a kind of for carbon dioxide methanation catalyst (Ni/Ce _xzr _1-xo ₂) and preparation method thereof, belong to catalyst preparation technical field.

Background technology

1902, french chemist PaulSabatier reported first catalytic hydrogenating reduction technology (the i.e. CO of carbon dioxide ₂methanation reaction): CO ₂(g)+4H ₂(g)=CH ₄(g)+2H ₂o (g) △ H ⁰298K=-252.9KJ.mol ^-1, CO ₂methanation reaction is CO ₂an important chemical reaction of recycling, the day by day exhausted and CO to solution gas reserves ₂the problem important in inhibitings such as caused ecology and environment.CO is reached by catalysis ₂methanation fast, becomes one of rather noticeable problem in C-1 chemistry research.

At current carried out CO ₂in the research of hydrogenation methanation reaction, the exploitation of catalyst is a focus.Chinese scholars expands large quantity research, RSCAdvances, and report in 5 (2015): 22759-76, active component Ni, Fe, Co, Ru, Rh, Pd, Pt, Ir etc. are dispersed in Al ₂o ₃, SiO ₂, TiO ₂, ZrO ₂, CeO ₂deng the CO on oxide carrier ₂methanation catalyst, because have relatively high catalytic activity and stability is extensively studied.By improving activity and the stability of method for preparing catalyst and optimization of catalysts component raising catalyst.Find by literature search, existing carbon dioxide methanation catalyst component and preparation method thereof, the cost of material of catalyst is high, and preparation method is loaded down with trivial details, and catalyst catalytic activity below 350 DEG C prepared by the method is low, poor stability, poor selectivity.

Summary of the invention

The object of the present invention is to provide and a kind of there is the carbon dioxide methanation catalyst (Ni/Ce that catalytic activity is high, catalytic stability good, production cost is low _xzr _1-xo ₂), this method for preparing catalyst is simple, easy to operate, cost is lower, has certain application prospect.

A kind of carbon dioxide methanation catalyst (Ni/Ce of the present invention _xzr _1-xo ₂), it is made up of carrier and active component, it is characterized in that, described carrier adopts cerium zirconium sosoloid, and it is with chemical general formula Ce _xzr _1-xo ₂represent, described active component is W metal, and wherein, the atomic molar of cerium, zirconium is than being x:(1-x), and 0<x<1, the content of W metal accounts for 10 ~ 40wt.% of carrier quality.

A kind of carbon dioxide methanation catalyst (Ni/Ce of the present invention _xzr _1-xo ₂) preparation method, mainly comprise following steps:

A. by a certain amount of nickel nitrate (Ni (NO ₃) ₂6H ₂o), cerous nitrate (Ce (NO ₃) ₃6H ₂o), zirconium nitrate (Zr (NO ₃) ₄5H ₂o) join respectively in 50ml deionized water, Ni is active component, with elemental metal, is mixed with at catalyst (Ni/Ce _xzr _1-xo ₂) in the content of W metal be the mixed solution of 10 ~ 40wt.%;

B. the mixed solution that step a prepares is moved into 80 DEG C of thermostat water baths, with 180 ~ 200 revs/min of speed uniform stirrings, when temperature reaches 80 DEG C, be that the sal volatile 100ml of 2mol/L pours in mixed solution by 100ml concentration, continue agitating heating, temperature remains on 80 DEG C; After constant temperature drying, obtain powder;

C. the powder after being dried by step b, in Muffle furnace, with the programming rate of 2 DEG C/min, rises to 500 DEG C of roasting 5h from room temperature; Then by the powder after above-mentioned roasting at 25 ~ 35kN/Cm ²pressure under to be placed in punching block extruded; With after through broken, sieve, obtaining particle diameter is 40 ~ 60 object particles;

D. the particle obtained by step c is in the hydrogen atmosphere of 30ml/min at reducing gas flow ,temperature is reductase 12 h at 400 DEG C, obtained Ni/Ce _xzr _1-xo ₂catalyst.

The features and advantages of the invention are as described below:

(1). the present invention is raw material with metal nitrate, take ammonium carbonate as precipitating reagent, has prepared CO by step precipitation method ₂methanation catalyst Ni/Ce _xzr _1-xo ₂(0≤x≤1), 250 ^oC~ 400 ^oc has higher catalytic activity and selective, and has high stability, can effective catalysis carbon dioxide hydrogenation reaction at ambient pressure, impels it to become methane.

(2). Catalyst for CO of the present invention ₂maximum conversion rate more than 90%, CH ₄maximum selectivity is 100%.

(3). method for preparing catalyst of the present invention is simple, easy to operate, cost is lower, has certain application prospect.

Accompanying drawing explanation

Fig. 1 is the X-ray diffractogram of carrier in embodiments of the invention 1-5.

Fig. 2 is 40%Ni/Ce in embodiments of the invention 4 _0.9zr _0.1o ₂catalyst is carrying out CO ₂x-ray diffractogram before hydrogenation methanation reaction.

Fig. 3 is that in embodiments of the invention 1,2,4, carrier loaded 40wt.%Ni catalyst is 7000ml/g.h in air speed, and temperature is 250 DEG C ~ 400 DEG C reactions, CO ₂hydrogenation methanation reaction catalytic evaluation result figure.

Fig. 4 is 40%Ni/Ce in embodiments of the invention 1 _0.9zr _0.1o ₂catalyst is at 300 DEG C, and air speed is 28000ml/gh and 52000ml/gh, 500 hours long-time reaction stability resolution charts.

Fig. 5 is that in embodiments of the invention 3, cerium zirconium mol ratio is the Ce of 9:1 _0.9zr _0.1o ₂the catalyst of carrier loaded different content Ni is 7000ml/g.h in air speed, 250 DEG C ~ 400 DEG C, CO ₂hydrogenation methanation reaction catalytic evaluation result figure.

Detailed description of the invention

By following examples, the present invention is further described, but the present invention is not limited in the present embodiment.

Embodiment 1

A. Ce (NO is taken ₃) ₃6H ₂o3.91g, Zr (NO ₃) ₄5H ₂o0.43g, Ni (NO ₃) ₂6H ₂o5.63g, adds deionized water 50ml, is stirred to dissolving and is mixed with mixed solution.

B. solution moves to 80 DEG C of water-baths, constantly stirs, and pours rapidly above-mentioned mixed solution into, continues to be stirred to evaporate to dryness, forward roasting in Muffle furnace to the sal volatile 100ml of the 2mol/L prepared, and is raised to 500 DEG C of roasting 5h from room temperature with the heating rate of 2 DEG C/min., support C e _0.9zr _0.1o ₂x-ray diffractogram as shown in Figure 1, in figure, the oxide of cerium zirconium defines solid solution Ce _0.9zr _0.1o ₂..

C. by the powder after roasting at 25 ~ 35kN/Cm ²pressure under extruded in punching block; With after through broken, sieve, obtaining particle diameter is 40 ~ 60 object particles.

D. the particle flow obtained is the H of 30ml/min _2,from room temperature 10 ^othe heating rate of C/min is warmed up to 400 DEG C, after reductase 12 h, namely obtains 40%Ni/Ce _0.9zr _0.1o ₂catalyst, as shown in Figure 2, in figure, is 40%Ni/Ce _0.9zr _0.1o ₂catalyst is carrying out CO ₂x-ray diffractogram before hydrogenation methanation reaction, as can be seen from Figure 2, through H ₂after reduction, the main component of catalyst is Ce _0.9zr _0.1o ₂nickel-loaded.

For verifying that catalyst of the present invention uses result, to carbon dioxide methanation (Ni/Ce of the present invention _xzr _1-xo ₂) catalyst evaluates, its catalyst activity evaluation method is as follows: carry out on a fixed bed, and catalyst is placed in the middle part of reactor flat-temperature zone, supports with quartz sand; CO ₂the experiment condition of methanation: normal pressure, temperature 250 DEG C ~ 400 DEG C, feed gas volume air speed is 7000ml/gh ~ 52000ml/gh, and feeding gas constitutive molar ratio is H ₂/ CO ₂=4:1, product mist is first through water condenser, preliminary hydro-extraction, again through loading the drying tube of calcium sulfate, remove further and generate remaining steam in gas, after stable reaction, start timing sample analysis, after purge drying process, gas detects product gas component by GC-9800 type chromatograph

CO ₂(g)+4H ₂(g)=CH ₄(g)+2H ₂O(g)

While there is carbon dioxide methanation reaction, can occur

CO ₂(g)+4H ₂(g)=CO(g)+2H ₂O(g)

CO ₂conversion ratio and CH ₄, the selective of CO passes through formulae discovery below:

In formula, X _cO2for CO ₂conversion ratio, S _iselective for product, N represents molar flow, and i is CH ₄, CO.

The 40%Ni/Ce obtained in embodiment 1 _0.9zr _0.1o ₂catalyst, at normal pressure, when feed gas volume air speed is 7000ml/gh, 250 DEG C ~ 400 DEG C reactions, calculates according to above-mentioned formula (1), formula (2), CO ₂conversion ratio at different temperatures, as shown in Figure 3, during 300 DEG C of reactions, CO ₂conversion ratio is up to 92.23%, CH ₄selective be 100%, when air speed is 28000ml/gh, CO ₂conversion ratio is 86.75%, CH ₄selective be 99.91%; Fig. 4 is 40%Ni/Ce _0.9zr _0.1o ₂catalyst is at 300 DEG C, and air speed is 28000ml/gh and 52000ml/gh, 500h hour long-time reaction stability resolution chart, and as can be seen from Figure 4, air speed is 28000ml/gh and 52000ml/gh, starts the stage of reaction, CO ₂conversion ratio is stabilized in 88.5% and 86.6% respectively, along with the prolongation in reaction time, and CO ₂conversion ratio does not change substantially, and at the end of 500h reaction, air speed is the corresponding CO of 28000ml/gh and 52000ml/gh. ₂conversion ratio reduces to 86.9% and 83.87% respectively, and the catalytic activity of catalyst remains unchanged, and has higher stability.

Embodiment 2

A. Ce (NO is taken ₃) ₃6H ₂o2.17g, Zr (NO ₃) ₄5H ₂o2.15g, Ni (NO ₃) ₂6H ₂o4.98g adds deionized water 50ml, is stirred to dissolving, is mixed with mixed solution.

B. the solution prepared is moved to 80 DEG C of water-baths, constantly stir, pour rapidly above-mentioned mixed solution into the sal volatile 100ml of 2mol/L, continue to be stirred to evaporate to dryness, forward roasting in Muffle furnace to, be raised to 500 DEG C of roasting 5h from room temperature with the heating rate of 2 DEG C/min and obtain powder, support C e _0.5zr _0.5o ₂x-ray diffractogram as shown in Figure 1, in figure, the oxide of cerium zirconium defines solid solution Ce _0.5zr _0.5o ₂..

C. by the powder after roasting at 25 ~ 35kN/Cm ²pressure under extruded in punching block; With after through broken, sieve, obtaining particle diameter is 40 ~ 60 object particles.

D. the particle flow obtained is the H of 30ml/min ₂, from room temperature with 10 ^othe heating rate of C/min is warmed up to 400 DEG C, after reductase 12 h, namely obtains 40%Ni/Ce _0.5zr _0.5o ₂catalyst.

The 40%Ni/Ce obtained in embodiment 2 _0.5zr _0.5o ₂catalyst, at normal pressure, feed gas volume air speed is under 7000ml/gh air speed, 250 DEG C ~ 400 DEG C reactions, calculates, CO according to above-mentioned formula (1), formula (2) ₂conversion ratio at different temperatures, as shown in Figure 3, during 300 DEG C of reactions, CO ₂conversion ratio is up to 90.43%, CH ₄selective be 100%.

Embodiment 3

A. Ce (NO is taken ₃) ₃6H ₂o3.91g, Zr (NO ₃) ₄5H ₂o0.43g, 3.51gNi (NO ₃) ₂6H ₂o adds deionized water 50ml, is stirred to dissolving and is mixed with mixed solution.

B. solution is moved to 80 DEG C of water-baths, constantly stir, pour rapidly above-mentioned mixed solution into the sal volatile 100ml of 2mol/L, continue to be stirred to evaporate to dryness, forward roasting in Muffle furnace to, be warmed up to 500 DEG C of roasting 5h from room temperature with the heating rate of 2 DEG C/min, support C e _0.9zr _0.1o ₂x-ray diffractogram as shown in Figure 1, in figure, the oxide of cerium zirconium defines solid solution Ce _0.9zr _0.1o ₂.

C. by the powder after roasting at 25 ~ 35kN/Cm ²pressure under extruded in punching block; With after through broken, sieve, obtaining particle diameter is 40 ~ 60 object particles.

D. the particle flow obtained is the H of 30ml/min ₂, from room temperature 10 ^othe heating rate of C/min is warmed up to 400 DEG C, after reductase 12 h, namely obtains 30%Ni/Ce _0.9zr _0.1o ₂catalyst.

The 30%Ni/Ce obtained in embodiment 3 _0.9zr _0.1o ₂catalyst is at normal pressure, and feed gas volume air speed is under 7000ml/gh air speed, 250 DEG C ~ 400 DEG C reactions, calculates, CO according to above-mentioned formula (1), formula (2) ₂conversion ratio at different temperatures as shown in Figure 4,300 DEG C of reactions, CO ₂conversion ratio is up to 90.46%, CH ₄selective be 100%.Fig. 4 is that cerium zirconium is than being 9:1 support C e _0.9zr _0.1o ₂load different content Raney nickel is 7000ml/g.h in air speed, 250 DEG C ~ 400 DEG C catalytic reaction evaluation result figure, as can be seen from Figure 4, and CO at the same reaction temperature ₂conversion ratio raises with the increase of nickel content; When 250 DEG C, 40%Ni/Ce _0.9zr _0.1o ₂in catalysis, CO ₂conversion ratio is up to 82.36%. temperature when being elevated to 300 DEG C, 40%Ni/Ce _0.9zr _0.1o ₂catalyst for CO ₂conversion ratio is up to 92.23%., due to carbon dioxide methanation reaction be exothermic reaction, temperature raise to 400 DEG C, CO on each catalyst ₂conversion ratio reduces a little.

Embodiment 4

A. nitric acid nickel (NO is taken ₃) ₂6H ₂o5.29g, cerous nitrate Ce (NO ₃) ₃6H ₂o3.04g, zirconium nitrate Zr (NO ₃) ₄5H ₂o1.29g joins in 50ml deionized water respectively, is stirred to dissolving and is mixed with mixed solution.

B. the solution configured is moved to 80 DEG C of thermostat water baths, continuous stirring, when temperature reaches 80 DEG C, pour rapidly the sal volatile 100ml of concentration 2mol/L into above-mentioned mixed solution, continue agitating heating evaporate to dryness, obtaining powder forwards in Muffle furnace by powder, rises to 500 DEG C of roastings 5 hours, support C e with the programming rate of 2 DEG C/min from room temperature _0.7zr _0.3o ₂x-ray diffractogram as shown in Figure 1, in figure, the oxide of cerium zirconium defines solid solution Ce _0.7zr _0.3o ₂.

C. by the powder after roasting at 25 ~ 35kN/Cm ²pressure under extruded in punching block, with after through broken, sieve, obtaining particle diameter is 40 ~ 60 object particles.

D. the particle flow obtained is the H of 30ml/min ₂, from room temperature with 10 ^oc/min is warmed up to 400 DEG C, after reductase 12 h, i.e. and obtained 40%Ni/Ce _0.7zr _0.3o ₂catalyst.

The 40%Ni/Ce obtained in embodiment 4 _0.7zr _0.3o ₂catalyst is at normal pressure, and feed gas volume air speed is 7000ml/gh, 250 DEG C ~ 400 DEG C reactions, calculates, CO according to above-mentioned formula (1), formula (2) ₂conversion ratio at different temperatures as shown in Figure 3,300 DEG C reaction time, CO ₂conversion ratio is up to 91.22%, CH ₄selective be 100%.

Embodiment 5

A. Ce (NO is taken ₃) ₃6H ₂o3.91g, Zr (NO ₃) ₄5H ₂o0.43g, Ni (NO ₃) ₂6H ₂o2.05g deionized water 50ml, is stirred to dissolving and is mixed with mixed solution.

B. solution moves to 80 DEG C of water-baths, constantly stirs, and pours rapidly above-mentioned mixed solution into, continues to be stirred to evaporate to dryness, forward roasting in Muffle furnace to the sal volatile 100ml of 2mol/L, is raised to 500 DEG C of roasting 5h, support C e from room temperature with the heating rate of 2 DEG C/min _0.9zr _0.1o ₂x-ray diffractogram as shown in Figure 1, in figure, the oxide of cerium zirconium defines solid solution Ce _0.9zr _0.1o ₂..

C. by the powder after roasting at 25 ~ 35kN/Cm ²pressure under extruded in punching block; With after through broken, sieve, obtaining particle diameter is 40 ~ 60 object particles.

D. the particle flow obtained is the H of 30ml/min ₂, from room temperature with 10 ^othe heating rate of C/min is warmed up to 400 DEG C, after reductase 12 h, namely obtains 20%Ni/Ce _0.9zr _0.1o ₂catalyst.

The 20%Ni/Ce obtained in embodiment 5 _0.9zr _0.1o ₂catalyst is at normal pressure, and feed gas volume air speed is under 7000ml/gh air speed, 250 DEG C ~ 400 DEG C reactions, calculates, CO according to above-mentioned formula (1), formula (2) ₂conversion ratio at different temperatures as shown in Figure 5., during 350 DEG C of reactions, CO ₂conversion ratio is up to 87.27%, CH ₄selective be 100%.

the project detected and the instrument of use thereof

XRD collection of illustrative plates mensuration is carried out, with the target product obtained by determination experiment and purity at RigakuD/max-2550X x ray diffractometer x to gained sample.Condition determination is CuKa(l=1.5406), 40KV, 100mA, Scanspeed:0.02 °/s.Analytical gas uses GC-9800 chromatogram, and service condition is: post case temperature is 80 ~ 130 ^oC, the temperature of vaporizer is 120 ^oc, the flow of high-purity argon carrier gas is 30mLmin ^-1, thermal conductivity detector (TCD) (TCD) temperature is 150 ^oc, its bridge stream is 70mA, and chromatographic column is 5A molecular sieve packed column (2m × Φ 3mm).

Claims (2)

1. a carbon dioxide methanation catalyst (Ni/Ce _xzr _1-xo ₂), it is made up of carrier and active component, it is characterized in that, described carrier adopts cerium zirconium sosoloid, and it is with chemical general formula Ce _xzr _1-xo ₂represent, described active component is W metal, and wherein, the atomic molar of cerium, zirconium is than being x:(1-x), and 0<x<1, the content of W metal accounts for 10 ~ 40wt.% of catalyst gross mass.

2. a carbon dioxide methanation catalyst (Ni/Ce _xzr _1-xo ₂) preparation method, mainly comprise following steps:

A. by a certain amount of nickel nitrate (Ni (NO ₃) ₂6H ₂o), cerous nitrate (Ce (NO ₃) ₃6H ₂o), zirconium nitrate (Zr (NO ₃) ₄5H ₂o) join respectively in 50ml deionized water, Ni is active component, with elemental metal, is mixed with at catalyst (Ni/Ce _xzr _1-xo ₂) in the content of W metal be the mixed solution of 10 ~ 40wt.%;

B. the mixed solution that step a prepares is moved into 80 DEG C of thermostat water baths, with 180 ~ 200 revs/min of speed uniform stirrings, when temperature reaches 80 DEG C, be that the sal volatile 100ml of 2mol/L pours in mixed solution by 100ml concentration, continue agitating heating, temperature remains on 80 DEG C; After constant temperature drying, obtain powder;

C. the powder after being dried by step b, in Muffle furnace, with the programming rate of 2 DEG C/min, rises to 500 DEG C of roasting 5h from room temperature; Then by the powder after above-mentioned roasting at 25 ~ 35kN/Cm ²pressure under to be placed in punching block extruded; With after through broken, sieve, obtaining particle diameter is 40 ~ 60 object particles;

D. the particle obtained by step c is in the hydrogen atmosphere of 30ml/min at reducing gas flow ,temperature is reductase 12 h at 400 DEG C, obtained Ni/Ce _xzr _1-xo ₂catalyst.