CN101555022A

CN101555022A - Preparation method of metal-modified SAPO-34 molecular sieve and catalyst containing the molecular sieve

Info

Publication number: CN101555022A
Application number: CNA200910082917XA
Authority: CN
Inventors: 朱伟平; 李艺; 邢爱华; 李飞; 田树勋
Original assignee: China Shenhua Coal to Liquid Chemical Co Ltd; Shenhua Group Corp Ltd
Current assignee: China Shenhua Coal to Liquid Chemical Co Ltd; Shenhua Group Corp Ltd
Priority date: 2009-04-22
Filing date: 2009-04-22
Publication date: 2009-10-14
Anticipated expiration: 2029-04-22
Also published as: CN101555022B

Abstract

The invention discloses a preparation method of a metal-modified SAPO-34 molecular sieve. The method includes: first mixing a template agent with metal salt solution to form a metal complex in the preparation process of raw powder of the molecular sieve; then adding materials such as aluminum source, phosphorus source, silicon source to prepare gel mixture; and finally obtaining the metal-modified SAPO-34 molecular sieve through ageing, hydrothermal crystallization, washing, drying, roasting and the like. The metal-modified SAPO-34 molecular sieve prepared by the method has comparatively high degree of crystallinity and can effectively improve the selectivity of ethene and propylene as reaction catalyst for preparing olefins by methanol. The invention discloses a preparation method of the metal-modified SAPO-34 molecular sieve and a catalyst containing the molecular sieve.

Description

A kind of metal-modified SAPO-34 molecular sieve and the Preparation of catalysts method that contains this molecular sieve

Technical field

The present invention is specifically related to a kind of novel metal modified SAPO-34 molecular sieve and contains metal-modified SAPO-34 molecular sieve Preparation of catalysts method.

Background technology

Novel silicon aluminium phosphate series molecular sieve (US 4440871, US4499327)-SAPO-n molecular sieve that U.S. combinating carbide company (UCC) researched and developed out in 1984, be be template with the organic amine, be aluminium source, phosphorus source and silicon source with hydrated aluminum oxide, phosphoric acid, silicon sol respectively, at first obtain having the organic amine/aluminum phosphate/silicon complex body of micropore phase, remove by roasting then that template (organic amine) obtains by hydrothermal crystallization method.SAPO-34 is wherein a kind of, and its similar chabazite has the three dimensional intersection duct, and the aperture is about 0.38nm, belongs to isometric system.Because it has suitable proton acidity, suitable pore passage structure, bigger specific surface area, absorption property and thermostability and hydrothermal stability etc. preferably preferably, makes it present catalytic activity and selectivity preferably in as the methanol to olefins reaction catalyzer.

Catalytic efficiency was relatively low when yet simple SAPO-34 was used as the methanol-to-olefins catalyzer, need carry out suitable modification to SAPO-34 usually.At present, improvement to the SAPO-34 molecular sieve mainly is that various metallic elements are introduced on the SAPO-34 framework of molecular sieve, change acidic zeolite and aperture size, obtain the acid site of aperture bore and medium tenacity, and the aperture diminishes and has limited macromolecular diffusion, help small-numerator olefin and optionally improve, thus the selectivity of low-carbon alkenes such as raising ethene, propylene.Usually, the synthesis mode of metal-modified SAPO-34 molecular sieve has two kinds, a kind of is two-step approach or post-treatment method, promptly at the synthetic laggard row metal ion modification of SAPO-34 molecular sieve, in the former powder of SAPO-34, introduce metal ion as (CN1067603C) such as Cai Guangyu by ion-exchange techniques, catalytic activity and ethene, propylene selectivity have had certain improvement, but it is more to generate the byproduct methane amount.Another kind of (single stage method) promptly in building-up process the change by starting raw material metal ion is introduced framework of molecular sieve or cation-bit, ditto to compare this method simple and convenient for the kind method.Prepare the SAPO molecular sieve of different metal modification in proper order by the interpolation of phosphorus source, aluminium source, silicon source, metal-salt, template as (US 4752651) such as Kaiser.Magnify and control etc. that (Microporous andMesoporous Materials 2008,116 684-692) mixes pseudo-boehmite earlier with phosphoric acid, silicon sol, stir afterwards adding template triethylamine and magnesium acetate have made magnesium-modified SAPO-34 molecular sieve.Aforesaid method all is to adopt to make phosphorus source and aluminium source form the aluminum phosphate skeleton earlier, then silicon source, template and metal-salt etc. are introduced in the skeleton, may make some template and metal-salt can not enter among the skeleton like this, finally influence the rerum natura and the catalytic performance of molecular sieve.Therefore, the preparation method of the better metal-modified SAPO-34 molecular sieve of development research is necessary.

Summary of the invention

At above-mentioned technical problem, the object of the invention is by at first forming metal-template complex compound, make materials such as aluminium source, phosphorus source, silicon source can wrap the outside surface that is attached to metal-template complex compound then, thereby form complex body, just can obtain the metal-modified SAPO-34 molecular sieve of metal adhesion on porous skeleton by roasting with micropore phase.

Therefore, the invention provides a kind of preparation method of metal-modified SAPO-34 molecular sieve, described method comprises the steps:

1) earlier template is mixed the formation metal complex with metal-salt, add materials such as aluminium source, phosphorus source, silicon source again, stirring mixed in 1-10 hour under 25-80 ℃, and the final blending GOLD FROM PLATING SOLUTION belongs to element: template: SiO ₂: Al ₂O ₃: P ₂O ₅: H ₂The mol ratio of O is 0.01-1.0: 1.0-5.0: 1.0: 2-1.5: 0.2-2.0: 20-200; Wherein, SiO ₂, Al ₂O ₃, P ₂O ₅Mol ratio be respectively that corresponding silicon source, aluminium source, the conversion of phosphorus source are SiO ₂, Al ₂O ₃, P ₂O ₅Mol ratio.

2) mixing solutions was worn out under 25-80 ℃ 1-24 hour.

3) crystallizing kettle of packing into of the mixing solutions after will wearing out airtightly is heated to crystallization temperature 150-250 ℃, carries out under constant crystallization temperature then crystallization 10-120 hour.

4) mixture after the crystallization is carried out centrifugation, filtration, washing after, solid sample obtains the former powder of metal-modified SAPO-34 molecular sieve by heat drying.

5) with the former powder of metal-modified SAPO-34 molecular sieve at 450-650 ℃ of following roasting 4-8 hour, metal-modified SAPO-34 molecular sieve.

In preparation method of the present invention, described template can be the template of this area routine, and as the organic amine template, the present invention is preferably tetraethyl ammonium hydroxide, triethylamine, diethylamine, morpholine or their any mixture.

In preparation method of the present invention, described metallic element is Ag, Cu, Mg, Co, Ni, Ca, Ba, Sr, Fe, Zn or their any mixture, and the content of described metallic element is 0.01～1.0% of molecular sieve weight.Metallic element described in the present invention is the form of their this areas hydrochlorate commonly used, for example, and metal nitrate, metal acetate salt, or the form of other hydrochlorate.

In preparation method of the present invention, described silicon source can be the silicon source of this area routine, and the present invention is preferably silicon sol, silicic acid, silicon-dioxide, white carbon black, water glass or the tetraethoxy of silica comprises 40 weight %, and they are mixture arbitrarily.

In preparation method of the present invention, described phosphorus source can be the phosphorus source of this area routine, includes but not limited to phosphoric acid, phosphoric acid salt or phosphite or they mixture arbitrarily, and further preferred phosphorus source is a phosphoric acid, and described phosphoric acid contains the ortho-phosphoric acid of 85 weight %.

In preparation method of the present invention, described aluminium source can be the aluminium source of this area routine, and the present invention is preferably pseudo-boehmite, aluminum isopropylate, aluminum oxide, aluminium hydroxide or they mixture arbitrarily.

The present invention also provides a kind of metal-modified SAPO-34 molecular sieve Preparation of catalysts method, and described method comprises the steps: with A) and quality summation meter B),

A) quality is the former powder of metal-modified SAPO-34 molecular sieve of the present invention of 10～100% preparation; And B) 0～90% binding agent mixes, 50～150 ℃ of dryings, and 350～650 ℃ of roastings moulding in 1～8 hour then promptly makes the metal-modified SAPO-34 molecular sieve catalyzer.

The present invention further preferred described method comprises the steps: with A) and quality summation meter B), A) quality is the former powder of metal-modified SAPO-34 molecular sieve of the present invention's preparation of 30～800%; And B) 20～70% binding agent mixes, 50～150 ℃ of dryings, and 350～650 ℃ of roastings moulding in 1～8 hour then promptly makes the metal-modified SAPO-34 molecular sieve catalyzer.

In the metal-modified SAPO-34 molecular sieve Preparation of catalysts method of the present invention, described binding agent is in aluminum oxide, aluminium hydroxide, aluminum phosphate, pure aluminium silicate, silicon oxide or the magnesium oxide or they make up arbitrarily.

In the metal-modified SAPO-34 molecular sieve Preparation of catalysts method of the present invention, described method also comprises the adding pore-forming material, described pore-forming material can be the pore-forming material of this area routine, the present invention is preferably sesbania powder, carboxymethyl cellulose or starch, and the consumption of described pore-forming material is 1～15% of a metal-modified SAPO-34 molecular sieve catalyst quality.

In the metal-modified SAPO-34 molecular sieve Preparation of catalysts method of the present invention, the content of metallic element is 0.01～1.0% of molecular sieve weight.

Compare with the molecular screen primary powder that prior art makes, the degree of crystallinity of the former powder of metal-modified SAPO-34 molecular sieve that the inventive method makes has had tangible improvement; And because various metallic elements are introduced on the SAPO-34 framework of molecular sieve, not only make metal-modified SAPO-34 molecular sieve have certain acidity, also can give oxidation-reduction quality, as methanol-to-olefins (MTO) catalysts the time, improve the selectivity of low-carbon alkene ethene and propylene.

When metal-modified SAPO-34 molecular sieve catalyzer of the present invention is used for methanol to olefins reaction, when temperature of reaction is 300～500 ℃, reaction pressure is 0～0.5MPa, and preferable reaction temperature is 400～500 ℃, the mass space velocity of methyl alcohol is 1.0～5.0 o'clock, and feed stock conversion can reach 100%.

The metal-modified SAPO-34 molecular sieve of the inventive method preparation has higher degree of crystallinity, can improve the selectivity of ethene and propylene effectively as the methanol to olefins reaction catalyzer.

Description of drawings

Fig. 1 is comparative example 1 a process flow sheet;

Fig. 2 is comparative example 2 a process flow sheet;

Fig. 3 is comparative example 3 a process flow sheet;

Fig. 4 is comparative example 4 a process flow sheet;

Fig. 5 is the process flow sheet of embodiment 1, embodiment 4;

Fig. 6 is the process flow sheet of embodiment 2, embodiment 3, embodiment 5;

Fig. 7 is comparative example 1-4, X-ray diffraction (XRD) figure of embodiment 1-5 products obtained therefrom.

Embodiment

Now further specify the present invention, but the present invention is not limited to this by following comparative example, embodiment and test example.

Comparative example's 1 ion exchange method is synthesized the AgAPSO-34 molecular sieve.

85% phosphoric acid of 12.3g, the pseudo-boehmite of 8.768g, the triethylamine of 16.16g, the deionized water of 49.568g, 40% silicon sol of 4.8g and the 1M silver nitrate solution of 30ml are prepared according to operation shown in Figure 1, wherein aging condition is: temperature: 25 ℃, and the time: 4 hours; Crystallization condition is: temperature: 200 ℃, and the time: 48 hours; Roasting condition: temperature: 550 ℃, the time: 7 hours; Get product (a) at last.

The comparative example 2

85% phosphoric acid of 12.3g, the pseudo-boehmite of 8.768g, 40% silicon sol of 4.8g, the triethylamine of 16.16g, the deionized water of 49.568g and the Silver Nitrate of 0.544g are prepared according to operation shown in Figure 2, wherein aging condition is: temperature: 25 ℃, and the time: 4 hours; Crystallization condition is: temperature: 200 ℃, and the time: 48 hours; Roasting condition: temperature: 550 ℃, the time: 7 hours; Get product (b) at last.

The comparative example 3

85% phosphoric acid of 12.3g, the pseudo-boehmite of 8.768g, 40% silicon sol of 4.8g, the triethylamine of 16.16g, the deionized water of 49.568g and the Silver Nitrate of 0.544g are prepared according to operation shown in Figure 3, wherein aging condition is: temperature: 25 ℃, and the time: 4 hours; Crystallization condition is: temperature: 200 ℃, and the time: 48 hours; Roasting condition: temperature: 550 ℃, the time: 7 hours; Get product (c) at last.

The comparative example 4

85% phosphoric acid of 12.3g, the pseudo-boehmite of 8.768g, 40% silicon sol of 4.8g, the triethylamine of 16.16g, the deionized water of 49.568g and the Silver Nitrate of 0.544g are prepared according to operation shown in Figure 4, wherein aging condition is: temperature: 25 ℃, and the time: 4 hours; Crystallization condition is: temperature: 200 ℃, and the time: 48 hours; Roasting condition: temperature: 550 ℃, the time: 7 hours; Get product (d) at last.

Embodiment 1

85% phosphoric acid of 12.3g, the pseudo-boehmite of 8.768g, 40% silicon sol of 4.8g, the triethylamine of 16.16g, the deionized water of 49.568g and the Silver Nitrate of 0.544g are prepared according to operation shown in Figure 5, wherein aging condition is: temperature: 25 ℃, and the time: 4 hours; Crystallization condition is: temperature: 200 ℃, and the time: 48 hours; Roasting condition: temperature: 550 ℃, the time: 7 hours; Get product (i) at last.

Embodiment 2

85% phosphoric acid of 12.3g, the pseudo-boehmite of 8.768g, 40% silicon sol of 4.8g, the triethylamine of 16.16g, the deionized water of 49.568g and the Silver Nitrate of 0.544g are prepared according to operation shown in Figure 6, wherein aging condition is: temperature: 25 ℃, and the time: 4 hours; Crystallization condition is: temperature: 200 ℃, and the time: 48 hours; Roasting condition: temperature: 550 ℃, the time: 7 hours; Get product (h) at last.

Embodiment 3

85% phosphoric acid of 12.3g, the pseudo-boehmite of 8.768g, 40% silicon sol of 4.8g, the triethylamine of 16.16g, the deionized water of 49.568g and the zinc nitrate of 0.58g are prepared according to operation shown in Figure 6, wherein aging condition is: temperature: 50 ℃, and the time: 8 hours; Crystallization condition is: temperature: 210 ℃, and the time: 68 hours; Roasting condition: temperature: 540 ℃, the time: 7.5 hours; Get product (g) at last.

Embodiment 4

85% phosphoric acid of 14.98g, the pseudo-boehmite of 10.69g, 40% silicon sol of 5.86g, the triethylamine of 19.55g, the deionized water of 60.29g and the magnesium nitrate of 0.5g are prepared according to operation shown in Figure 5, wherein aging condition is: temperature: 35 ℃, and the time: 15 hours; Crystallization condition is: temperature: 220 ℃, and the time: 36 hours; Roasting condition: temperature: 600 ℃, the time: 6 hours; Get product (f) at last.

Embodiment 5

85% phosphoric acid of 14.98g, the pseudo-boehmite of 10.69g, 40% silicon sol of 5.86g, the triethylamine of 19.55g, the deionized water of 60.29g and the nickelous nitrate of 0.57g are prepared according to operation shown in Figure 6, wherein aging condition is: temperature: 60 ℃, and the time: 2 hours; Crystallization condition is: temperature: 180 ℃, and the time: 72 hours; Roasting condition: temperature: 500 ℃, the time: 8 hours; Get product (e) at last.

The preparation of embodiment 6 molecular sieve catalysts

Get Comparative Examples 1,2,3,4 respectively, former powder 6 grams that make among the embodiment 1,2 are with rAl ₂O ₃H ₂O6 gram, sesbania powder 2 grams mix, and add 9 milliliters in the rare nitric acid of 3wt%, mediate, extruded moulding, 120 ℃ of dry down 8 hours, 600 ℃ following roastings 3 hours, and broken back sieve is got 20～40 purpose granularity parts, waits to check and rate.

The detection of test example 1 degree of crystallinity

Method: detect according to the degree of crystallinity of X-ray diffraction method to embodiment 1-5, comparative example 1-4 products obtained therefrom, and the degree of crystallinity of embodiment 2 products obtained therefroms is set at 100%, degree of crystallinity with other embodiment and comparative example's product compares with it then, the results are shown in Table 1.

The former powder degree of crystallinity of each embodiment of table 1, embodiment gained molecular sieve

Sample	Relative crystallinity/%
Sample	Relative crystallinity/%	Comparative Examples 1	82.87
Comparative Examples 2	89.38	Comparative Examples 1	82.87
Comparative Examples 2	89.38	Comparative Examples 3	84.23
Comparative Examples 4	85.72	Comparative Examples 3	84.23
Comparative Examples 4	85.72	Embodiment 1	91.22
Embodiment 2	100	Embodiment 1	91.22
Embodiment 2	100	Embodiment 3	92.88
Embodiment 4	92.79	Embodiment 3	92.88
Embodiment 4	92.79	Embodiment 5	91.53

As can be found from Table 1, under the constant situation of other condition, significantly improved the degree of crystallinity of metal-modified SAPO-34 molecular sieve according to preparation metal-modified SAPO-34 technology shown in the present.

The examination of test example 2 molecular sieve catalysts

Adopt fixed-bed catalytic reactor, embodiment 1, the embodiment 2, Comparative Examples 1, Comparative Examples 2, Comparative Examples 3, the Comparative Examples 4 that obtain are carried out catalyzer examination experiment, experiment condition: loaded catalyst 2.0 grams, 450 ℃ of temperature of reaction, air speed are 3h ^-1, the results are shown in following table 2.

Table 2 methanol conversion system alkene appraisal result

	Embodiment 1	Embodiment 2	The comparative example 1	The comparative example 2	The comparative example 3	The comparative example 4
	Embodiment 1	Embodiment 2	The comparative example 1	The comparative example 2	The comparative example 3	The comparative example 4	Methanol conversion (%)	100	100	100	100	100	100
CH ₄	2.32	2.42	3.52	3.31	3.07	3.14	Methanol conversion (%)	100	100	100	100	100	100
CH ₄	2.32	2.42	3.52	3.31	3.07	3.14	C ₂H ₄	44.98	45.7	42.08	44.33	41.37	41.14
C ₂H ₆	0.08	0.07	1.90	0.66	1.57	1.56	C ₂H ₄	44.98	45.7	42.08	44.33	41.37	41.14
C ₂H ₆	0.08	0.07	1.90	0.66	1.57	1.56	C ₃H ₆	44.15	43.41	39.11	38.60	40.13	39.66
C ₃H ₈	2.22	2.17	2.56	5.02	3.45	3.67	C ₃H ₆	44.15	43.41	39.11	38.60	40.13	39.66
C ₃H ₈	2.22	2.17	2.56	5.02	3.45	3.67	C ₄H ₈	0.67	0.59	1.41	0.62	2.13	2.15
C ₄H ₁₀	0.89	0.99	1.58	0.02	1.32	1.45	C ₄H ₈	0.67	0.59	1.41	0.62	2.13	2.15
C ₄H ₁₀	0.89	0.99	1.58	0.02	1.32	1.45	C ₅ ⁺	0.65	0.60	0.89	0.70	0.78	0.76
CO ₂	0.42	0.37	0.67	0.84	0.45	0.53	C ₅ ⁺	0.65	0.60	0.89	0.70	0.78	0.76
CO ₂	0.42	0.37	0.67	0.84	0.45	0.53	CO	0.30	0.25	0.56	0.58	0.40	0.43
Carbon deposit	3.32	3.43	5.72	5.32	5.33	5.51	CO	0.30	0.25	0.56	0.58	0.40	0.43
Carbon deposit	3.32	3.43	5.72	5.32	5.33	5.51	C ₂ ^＝+C ₃ ^＝	89.13	89.11	81.19	82.93	81.50	80.80

Conclusion: show the former powder preparation process of metal modified molecular screen from table 1, table 2, adopt earlier template to be mixed with metal salt solution and form metal complex, and then add materials such as aluminium source, phosphorus source, silicon source and be prepared into gel mixture, metal-modified SAPO-34 molecular sieve through the preparation of operations such as overaging, hydrothermal crystallizing, washing, drying and roasting has relative higher degree of crystallinity, can improve the selectivity of low-carbon alkene (ethene and propylene) effectively as the methanol to olefins reaction catalyzer.

Claims

1, a kind of method of metal-modified SAPO-34 molecular sieve preparation is characterized in that described method comprises the steps:

1) earlier template is mixed the formation metal complex with metal-salt, and then add aluminium source, phosphorus source and silicon source, stirring mixed in 1-10 hour under 25-80 ℃; The final blending GOLD FROM PLATING SOLUTION belongs to element: template: SiO ₂: Al ₂O ₃: P ₂O ₅: H ₂The mol ratio of O is 0.01-1.0: 1.0-5.0: 2-1.5: 1.0: 0.2-2.0: 20-200;

2) mixing solutions was worn out under 25-80 ℃ 1-24 hour;

3) crystallizing kettle of packing into of the mixing solutions after will wearing out airtightly is heated to crystallization temperature 150-250 ℃, carries out under constant crystallization temperature then crystallization 10-120 hour;

4) mixture after the crystallization is carried out centrifugation, filtration, washing after, solid sample obtains the former powder of metal-modified SAPO-34 molecular sieve by heat drying;

2, method according to claim 1 is characterized in that, described template is tetraethyl ammonium hydroxide, triethylamine, diethylamine, morpholine or their any mixture.

3, according to claims 1 described method, it is characterized in that, described metallic element is Ag, Cu, Mg, Co, Ni, Ca, Ba, Sr, Fe, Zn or their any mixture, and the content of wherein said metallic element is 0.01～1.0% of molecular sieve weight.

4, method according to claim 1 is characterized in that, described silicon source is the silicon sol, silicic acid, silicon-dioxide, white carbon black, water glass, tetraethoxy of 40 weight % or they mixture arbitrarily.

5, method according to claim 1 is characterized in that, described phosphorus source is phosphoric acid, phosphoric acid salt or phosphite or they mixture arbitrarily; Preferred phosphorus source is a phosphoric acid, and described phosphoric acid to contain be 85% ortho-phosphoric acid by weight.

6, method according to claim 1 is characterized in that, described aluminium source is pseudo-boehmite, aluminum isopropylate, aluminum oxide, aluminium hydroxide or they mixture arbitrarily.

7, a kind of metal-modified SAPO-34 molecular sieve Preparation of catalysts method is characterized in that described method comprises the steps: with A) and quality summation meter B),

A) quality is the former powder of metal-modified SAPO-34 molecular sieve that 10～100% the arbitrary described method of claim 1-6 makes; With

B) 0～90% binding agent;

Mix, 50～150 ℃ of dryings in 350～650 ℃ of roastings moulding in 1～8 hour, promptly make the metal-modified SAPO-34 molecular sieve catalyzer then.

8, method according to claim 7 is characterized in that, described method comprises the steps: with A) and quality summation meter B),

A) quality is the former powder of metal-modified SAPO-34 molecular sieve that 30～80% the arbitrary described method of claim 1-6 makes, and wherein, the content of described metallic element is 0.01～1.0% of molecular sieve weight; With

B) 20～70% binding agent;

Mix, 50 ℃～150 ℃ dryings in 350 ℃～650 ℃ roastings moulding in 1～8 hour, promptly make the metal-modified SAPO-34 molecular sieve catalyzer then.

9, method according to claim 8 is characterized in that, described binding agent is that make up arbitrarily aluminum oxide, aluminium hydroxide, aluminum phosphate, pure aluminium silicate, silicon oxide, magnesium oxide or they.

10, method according to claim 9 is characterized in that, described method also comprises the adding pore-forming material, and described pore-forming material is sesbania powder, carboxymethyl cellulose or starch; The consumption of pore-forming material is 1～15% of a metal-modified SAPO-34 molecular sieve catalyst quality.