CN104117361A - Copper-based catalyst by use of thorium as assistant for methanol synthesis and preparation method thereof - Google Patents

Abstract

The invention provides a copper-based catalyst by use of thorium as an assistant for methanol synthesis and a preparation method thereof, and relates to the copper-based catalyst for methanol synthesis. The copper-based catalyst is prepared from the following ingredients by weight percent: 0.1-2% of thorium oxide, 25-75% of copper oxide, 20-55% of zinc oxide and the balance being aluminum oxide. A coprecipitation method is adopted for preparation, and the pore diameter, the activity and the thermal resistance of the catalyst for methanol synthesis are improved. Compared with the catalyst free of thorium oxide, the catalyst added with 0.2-0.5% of thorium oxide serving as the assistant has the advantages that the pore diameter is increased to 8.65-8.74nm from 6.91nm, the initial activity is improved by 15%-18%, and the activity after thermal resistance is improved by 7-13%; the thorium oxide doping method is simple and the doping amount is low.

Description

Thorium is made Cu-Based Catalysts for Methanol Synthesis of auxiliary agent and preparation method thereof

Technical field

The present invention relates to Cu-Based Catalysts for Methanol Synthesis, especially relate to a kind of thorium and make Cu-Based Catalysts for Methanol Synthesis of auxiliary agent and preparation method thereof.

Background technology

Methyl alcohol is a kind of important Organic Chemicals, is widely used in agricultural chemicals, medicine, dyestuff, coating and national defense industry.Along with the change of scientific and technical development and world today's energy resource structure, become a kind of trend as new petrochemical material source with methyl alcohol.By the industrialization of synthesis gas synthesizing methanol, generally adopt in the world at present be in, low-pressure vapor phase method synthesizing methanol, the catalyst using is mainly the mixed oxide of copper, zinc, aluminium.But because the thermal discharge of synthesizing methanol reaction is large, easily cause copper-based catalysts inactivation and shorten catalyst service life.When using containing low CO ₂synthesis gas synthesizing methanol time, as still adopted Cu-Zn-Al three-way catalyst, because reactor feed gas has strong reproducibility, often bring Cu ⁺catalytic active species is easily reduced to Cu ⁰and cause the problems such as catalysqt deactivation.How to improve the heat endurance of copper-based catalysts, extending its service life is the problem that people pay close attention to.This patent application ion doping valence state penalty method is with rugged catalyst surface C u ⁺the principle of species valence state is added the metal ion Th that a small amount of valence state is higher in Cu-Zn-Al tri-component low pressure methanol synthetic catalysts ⁴⁺, making Cu-Zn-Al-Th methanol synthesis catalyst, this catalyst has good catalytic activity and heat resistance.

It is by Cu that Chinese patent CN1810357A discloses a kind of catalyst for methanol, Zn, Al, the nitrate mixed solution of Li and Na ₂cO ₃the catalyst that solution co-precipitation obtains.Wherein the doping of Li makes the scope of application of catalyst wider, is not only applicable to low CO ₂synthesis gas, be also applicable to high CO ₂synthesis gas, at CO ₂proportion still keeping higher activity and selectivity when being 27%.The Li Congming of Tokyo gas synthesis Co., Ltd, the research such as Xingdong Yuan and Kaoru Fujimoto find the to have adulterated CuO/ZnO/Al of Zr ₂o ₃catalyst, metallic Z r can improve the surface area of copper, and can increase metallic copper in surperficial concentration, these all have good help Catalysis A:General469 (2014) 306-311 to the activity that improves reaction).C.Seller and the R.Prins in Swiss Confederation's science and technology research institute's chemical technology laboratory find at Pd-SiO ₂the Li of trace of adulterating in catalst for synthesis of methanol can well improve the activity of catalyst, and has very high selective (99%) (Catalysis Letters 47 (1997) 83-89) for methyl alcohol.

Although the auxiliary agent of metal-doped use has in the past improved space-time yield and conversion ratio, but there is the production process complexity of catalyst, be not suitable for the large-scale higher shortcoming of metal promoter cost of producing and adding.

Summary of the invention

The object of this invention is to provide can increase copper-based catalysts aperture, improves active and stable on heating a kind of thorium and make Cu-Based Catalysts for Methanol Synthesis of auxiliary agent and preparation method thereof.

Described thorium is made the oxide that the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent comprises Cu, Zn ﹑ Al and Th, in copper-based catalysts, each constituent content is by mass percentage: thorium oxide 0.1%～2%, cupric oxide 25%～75%, zinc oxide 20%～55%, surplus is aluminium oxide; Hundred parts of content of quality of the each composition of described catalyst are preferably, thorium oxide 0.2%～0.5%, and cupric oxide 60%～75%, zinc oxide 20%～25%, surplus is aluminium oxide.

Described thorium is made the preparation method of the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent, comprises the following steps:

1) by the Cu of metering, Zn, Th nitrate is separately soluble in water, and being made into respectively molar concentration is the Cu (NO of 1mol/L ₃) ₂, 1mol/L Zn (NO ₃) ₂th (the NO of solution and 0.045mol/L ₃) ₄solution; Again by Cu (NO ₃) ₂and Zn (NO ₃) ₂solution mixing system becomes Cu (NO ₃) ₂and Zn (NO ₃) ₂mixed solution, be designated as mixed solution A, then by Th (NO ₃) ₄solution adds in mixed solution A, makes Cu (NO ₃) ₂, Zn (NO ₃) ₂and Th (NO ₃) ₄mixed solution, be designated as mixed solution B;

2) by anhydrous Na ₂cO ₃soluble in water, be made into the Na that molar concentration is 0.5mol/L ₂cO ₃solution;

3) Na that is 0.5mol/L by molar concentration ₂cO ₃solution is heated to after 65～82 DEG C, then adds in mixed solution B, and control pH=8～9 are terminal, aging after, obtain copper zinc thorium basic carbonate salt mixture;

4), by soluble in water the soluble-salt of Al, being made into molar concentration is the Al soluble-salt solution of 1mol/L; Ammonia spirit is joined to Al soluble-salt solution, make aluminium colloidal sol;

5) by step 3) copper zinc thorium basic carbonate salt mixture and the step 4 of gained) the aluminium colloidal sol of gained mixes, then sediment is filtered and drained, after washing, refilter and drain, gained filter cake is dried, calcining, and compression molding obtains thorium makes the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent.

In step 1) in, described water can adopt deionized water.

In step 2) in, described water can adopt deionized water.

In step 3) in, described aging condition can be at 80～85 DEG C aging 1h.

In step 4) in, described water can adopt deionized water; Described ammonia spirit ammoniacal liquor by volume: water can be 1: 5; Describedly after being joined to Al soluble-salt solution, ammonia spirit can at 70～85 DEG C, stir 1h; The soluble-salt of described Al can adopt aluminum nitrate.

In step 5) in, described washing can adopt distilled water washing 6 times; The condition of described oven dry can be dried 2h at 110 DEG C; The condition of described calcining can be at 330 DEG C of calcining 3h.

Compared with the methanol synthesis catalyst of preparing with conventional method, the present invention can improve aperture, activity and the heat resistance of methanol synthesis catalyst.Add the catalyst of 0.2%～0.5% (mass percent) thorium oxide auxiliary agent compared with not adding the catalyst of thorium oxide, aperture is by 6.91nm reaming to 8.65～8.74nm, initial activity has improved 15%～18%, heat-resisting rear active raising 7%～13%.The present invention uses the method for thorium oxide doping simple, and the amount of doping is few, has good application value and scientific research and is worth.

Detailed description of the invention

Below in conjunction with specific embodiment, further set forth the present invention.These embodiment only limit to the present invention is described and are not used in and limit the scope of the invention.

In the following embodiments, catalyst adopts low-concentration hydrogen (H before use ₂/ N ₂=3/97) hydrogen nitrogen mixed gas reductase 12 0h, the highest reduction temperature is 235 DEG C.The activity rating of catalyst carries out on miniature fixed-bed reactor, the critical piece of this reaction unit comprises that (Chinese Shanghai Shi Yan circuit Co., Ltd produces SK2-1-8 type tube type resistance furnace, rated power 1kw, rated voltage 220v), built-in diameter 8mm and the crystal reaction tube of long 60cm, valve (from Xiong Chuan company), flowmeter (from Beijing company of Sevenstar-HC) and pressure gauge (from Beijing company of Sevenstar-HC).Loaded catalyst is 0.5ml, and unstripped gas consists of CO: H ₂: CO ₂: N ₂=14: 76: 5: 5 (volume ratio), reaction pressure is 5.0MPa, air speed is 10000h ^-1, evaluation temperature is 230 DEG C, measurement result is called initial activity; Then catalyst is through 400 DEG C of heat treatment 5h in synthetic atmosphere, then the result that drops to 230 DEG C of mensuration is called after heat treatment active.Product gas chromatograph analysis, the activity of catalyst is with methyl alcohol space-time yield (g.ml ^-1 _cat.h ^-1) represent.Space-time yield is defined as:

$\mathrm{STY}=\frac{A\×C^0\×V^0\×S}{A^0\×L}$ (g.ml ^-1 _cat.h ^-1)

The peak area of methyl alcohol in A-product; A ⁰the peak area of the methyl alcohol standard liquid of-certain volume;

C ⁰concentration (the mol.l of-methyl alcohol standard liquid ^-1); V ⁰the volume of-methyl alcohol standard liquid;

S-air speed; L-sample feeding pipe volume.

Embodiment 1

The preparation of copper zinc-aluminium thorium mixed oxide catalyst

1. getting concentration is 1molL ^-1cu (NO ₃) ₂solution 140mL and concentration are 1molL ^-1zn (NO ₃) ₂solution 60mL, is placed in 400mL container, is uniformly mixed;

2. getting concentration is the Th (NO of 0.045mol/L ₃) ₄solution 1ml adds in appeal solution, is uniformly mixed and makes Cu (NO ₃) ₂, Zn (NO ₃) ₂and Th (NO ₃) ₄mixed solution;

3. by the Na of metering ₂cO ₃solution is heated to 65 DEG C, it is joined to Cu (NO prepared by above-mentioned steps 2 under rapid stirring ₃) ₂, Zn (NO ₃) ₂and Th (NO ₃) ₄mixed solution in, control pH=9.0 is terminal, aging 1h at 85 DEG C obtains copper zinc thorium basic carbonate salt mixture;

4. Al (the NO that is 1mol/L by 18ml concentration ₃) ₃solution is heated to 82 DEG C, under rapid stirring, the volume ratio ammonia spirit 45ml of 1: 5 is joined to Al (NO ₃) ₃in solution, make aluminium colloidal sol, gained aluminium colloidal sol is for subsequent use after stirring 1h;

5. by the copper of gained, zinc, the aluminium colloidal sol of thorium basic carbonate salt mixture and step 4 gained mixes to obtain a sediment, sediment is filtered and is drained, repeatedly with distilled water washing 6 times;

Filter drain, gained filter cake is dried 2h at 110 DEG C, pulverize, at 330 DEG C at Muffle furnace roasting 3h;

7. after the prepared catalyst compressing tablet of step 6, pulverize and sieve, get 20～40 order catalyst samples for subsequent use.The catalyst of so making contains thorium oxide 0.2% (mass percent), cupric oxide 60%, and zinc oxide 25%, aluminium oxide 14.8%, is designated as Cat1.Activity rating the results are shown in table 1.

Embodiment 2～4

Preparation process is identical with embodiment 1, and except in the 2nd step, the addition of thorium nitrate auxiliary agent is respectively 0.045mol/L Th (NO ₃) ₄solution 2.5ml, ThO in the catalyst that 5ml and 10ml. so make ₂quality percentage composition be respectively 0.5%, 1% and 2%, be designated as respectively cat2, cat3, cat4.Activity rating the results are shown in table 1.

Embodiment 5

Preparation process is identical with embodiment 1, and except in the 1st step, concentration is 1molL ^-1cu (NO ₃) ₂solution is that 120mL and concentration are 1molL ^-1zn (NO ₃) ₂solution is 80ml; In the catalyst of so making, ThO ₂quality percentage composition be 0.2%, cupric oxide quality percentage composition 55%,, zinc oxide quality percentage composition 30%, quality of alumina percentage composition 14.8%, is designated as cat5.Activity rating the results are shown in table 1.

Embodiment 6

Preparation process is identical with embodiment 1, except concentration in step 1 is 1molL ^-1cu (NO ₃) ₂solution is that 160mL and concentration are 1molL ^-1zn (NO ₃) ₂solution is 40mL.ThO in the catalyst of so making ₂content 0.2% (mass percent), cupric oxide 65% (mass percent), zinc oxide 20% (mass percent), aluminium oxide 14.8% (mass percent), is designated as cat6.Activity rating the results are shown in table 1.

Embodiment 7

Preparation process is identical with embodiment 1 except in step 1, and concentration is 1molL ^-1cu (NO ₃) ₂solution is that 60mL and concentration are 1molL ^-1zn (NO ₃) ₂solution is 140mL; In step 2, getting concentration is the Th (NO of 0.045mol/L ₃) ₄solution 3ml adds in appeal solution, in the catalyst of so making, and ThO ₂content is 0.5% (mass percent), cupric oxide 25% (mass percent), and zinc oxide 55% (mass percent), aluminium oxide 14.5% (quality hundred umbers), is designated as cat7.Activity rating the results are shown in table 1.

Comparative example 1

The making of comparative example 1 catalyst is the same with the making step of embodiment 1.Just do not add the co-precipitation of thorium nitrate solution.Activity rating the results are shown in table 1.

The catalyst activity evaluation result of table 1: embodiment

CO conversion ratio calculates

$X_{\mathrm{CO}}(\%)=\frac{n_{\mathrm{CO}}^0-n_{\mathrm{CO}}}{n_{\mathrm{CO}}^0}\×100\%=(1-\frac{C_{\mathrm{CO}}V}{C_{\mathrm{CO}}^0{V}^0})\×100\%$

Due to $C_{N2}^0=\frac{n_{N_2}^0}{V^0},C_{N2}=\frac{n_{N_2}}{V},$ And $n_{N_2}^0=n_{N_2},$ $X_{\mathrm{CO}}(\%)=(1-\frac{C_{\mathrm{CO}}/C_{N_2}}{C_{\mathrm{CO}}^0/C_{N_2}^0})\×100\%$

the amount of substance of-reactor inlet CO; n _cOthe amount of substance of-reactor outlet CO;

the volumn concentration of-reactor inlet CO; C _cO-reactor outlet CO volumn concentration;

-reactor inlet N ₂amount of substance; -reactor outlet N ₂amount of substance;

-reactor inlet N ₂volumn concentration; -reactor outlet N ₂volumn concentration;

V ⁰the volume of-reactor inlet gas; The volume of V-reactor outlet gas.

Claims (10)

1. thorium is made the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent, it is characterized in that the oxide that comprises Cu, Zn ﹑ Al and Th, in copper-based catalysts, each constituent content is by mass percentage: thorium oxide 0.1%～2%, cupric oxide 25%～75%, zinc oxide 20%～55%, surplus is aluminium oxide.

2. thorium is made the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent as claimed in claim 1, it is characterized in that by mass percentage in copper-based catalysts, each constituent content is: thorium oxide 0.2%～0.5%, cupric oxide 60%～75%, zinc oxide 20%～25%, surplus is aluminium oxide.

3. thorium is made the preparation method of the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent as claimed in claim 1, it is characterized in that comprising the following steps:

1) by the Cu of metering, Zn, Th nitrate is separately soluble in water, and being made into respectively molar concentration is the Cu (NO of 1mol/L ₃) ₂, 1mol/L Zn (NO ₃) ₂th (the NO of solution and 0.045mol/L ₃) ₄solution; Again by Cu (NO ₃) ₂and Zn (NO ₃) ₂solution mixing system becomes Cu (NO ₃) ₂and Zn (NO ₃) ₂mixed solution, be designated as mixed solution A, then by Th (NO ₃) ₄solution adds in mixed solution A, makes Cu (NO ₃) ₂, Zn (NO ₃) ₂and Th (NO ₃) ₄mixed solution, be designated as mixed solution B;

2) by anhydrous Na ₂cO ₃soluble in water, be made into the Na that molar concentration is 0.5mol/L ₂cO ₃solution;

3) Na that is 0.5mol/L by molar concentration ₂cO ₃solution is heated to after 65～82 DEG C, then adds in mixed solution B, and control pH=8～9 are terminal, aging after, obtain copper zinc thorium basic carbonate salt mixture;

4), by soluble in water the soluble-salt of Al, being made into molar concentration is the Al soluble-salt solution of 1mol/L; Ammonia spirit is joined to Al soluble-salt solution, make aluminium colloidal sol;

5) by step 3) copper zinc thorium basic carbonate salt mixture and the step 4 of gained) the aluminium colloidal sol of gained mixes, then sediment is filtered and drained, after washing, refilter and drain, gained filter cake is dried, calcining, and compression molding obtains thorium makes the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent.

4. thorium is made the preparation method of the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent as claimed in claim 3, it is characterized in that in step 1), 2), 4) in, described hydromining deionized water.

5. thorium is made the preparation method of the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent as claimed in claim 3, it is characterized in that in step 3) in, described aging condition is aging 1h at 80～85 DEG C.

6. thorium is made the preparation method of the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent as claimed in claim 3, it is characterized in that in step 4) in, described ammonia spirit ammoniacal liquor by volume: water is 1: 5.

7. thorium is made the preparation method of the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent as claimed in claim 3, it is characterized in that in step 4) in, describedly after being joined to Al soluble-salt solution, ammonia spirit stirs 1h at 70～85 DEG C.

8. thorium is made the preparation method of the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent as claimed in claim 3, it is characterized in that in step 4) in, the soluble-salt of described Al is aluminum nitrate.

9. thorium is made the preparation method of the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent as claimed in claim 3, it is characterized in that in step 5) in, described washing adopts distilled water washing 6 times.

10. thorium is made the preparation method of the Cu-Based Catalysts for Methanol Synthesis of auxiliary agent as claimed in claim 3, it is characterized in that in step 5) in, the condition of described oven dry is to dry 2h at 110 DEG C; The condition of described calcining is at 330 DEG C of calcining 3h.