CN104229829B

CN104229829B - The method preparing fine grain SAPO-34 molecular sieve

Info

Publication number: CN104229829B
Application number: CN201310237106.9A
Authority: CN
Inventors: 管洪波; 刘红星; 赵昱; 钱坤
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2013-06-17
Filing date: 2013-06-17
Publication date: 2016-08-24
Anticipated expiration: 2033-06-17
Also published as: CN104229829A

Abstract

The invention provides a kind of method preparing little crystal grain SAPO 34 molecular sieve, mainly solve the prior synthesizing method gained SAPO 34 larger-size problem of zeolite crystal, feature is to promote the synthesis of small crystal grain molecular sieve by adding the crystal seed of defect sturcture.The present invention includes following step by employing: by initial crystallization liquid hydrothermal crystallizing 1 ~ 10 h at 200 ~ 250 DEG C of SAPO 34 molecular sieve, after solid-liquid separation, it is thus achieved that SAPO 34 crystal seed that lattice defect is more；Described crystal seed is added in the initial crystallization liquid of SAPO 34, and at 140 ~ 170 DEG C after hydrothermal treatment consists 0.1 ~ 4 h, it is dissolved as finally rising the fine pieces of structure directing and nucleation, then it is warming up to 180 ~ 250 DEG C and continues hydrothermal crystallizing, obtain the technical scheme of little crystal grain SAPO 34 zeolite product, preferably resolve this problem, can be used for preparing in the commercial production of little crystal grain SAPO 34 molecular sieve.

Description

The method preparing fine grain SAPO-34 molecular sieve

Technical field

The present invention relates to the preparation method of a kind of SAPO molecular sieve, especially relate to a kind of fine grain SAPO-34 molecular sieve Preparation method.

Background technology

Ethylene and propylene are the basic organic chemical industry raw materials that chemical industry is important, play in modern petroleum and chemical industry Very important effect.In recent years, along with day by day shortage and crude oil price the most high of Global Oil resource, by tradition stone The disparities between supply and demand that oil circuit line production ethylene and propylene are brought tend to nervous, and various countries are devoted to develop new non-petroleum and produce alkene The process route of hydrocarbon.Wherein, coal or natural gas are by synthesis gas (CO+H₂) it is current public affairs via the technique of preparing light olefins from methanol The technology path of the most application prospect recognized.Rich coal resources in China, the energy resource structure that petroleum resources are relatively deficient also determines Once the process route of olefin hydrocarbon making by coal is got through, will be to expanding China's traditional coal chemical industry development space, it is ensured that country Energy security has important and far-reaching meaning.At present, the coal gasification in olefin hydrocarbon making by coal technological process, synthesising gas systeming carbinol are Develop into the coal chemical technology of maturation, and the industrialization technology of methanol-to-olefins (Methanol to Olefin is called for short MTO) is opened Send out be then this process route realize key link.

The core of methanol-to-olefins technology is the exploitation of molecular sieve catalyst, and the catalyst that methanol-to-olefins uses in early days is many For Si-Al zeolite molecular sieve, such as ZSM-5, but its aperture is relatively large, and acidity is too strong, and yield of light olefins is the highest.Nineteen eighty-two, American Association carbon compound company (UCC) synthesizes SAPO series silicoaluminophosphamolecular molecular sieves first, the most noticeable Being SAPO-34 molecular sieve, it has class chabazite structure, has less aperture, moderate acid and stronger hydro-thermal simultaneously Stability, shows the selectivity of light olefin of excellence in catalysis methanol reaction for preparing light olefins, thus causes China and foreign countries' research The extensive concern of person.

There are some researches show, in MTO reacts, the SAPO-34 molecular sieve of small particle shortens due to duct, beneficially reactant With the diffusion of product, apparent activity and diene (ethylene+propylene) selectivity of molecular sieve catalyst can be improved, and effectively suppress Reaction depth, so carbon deposition quantity is low.

Many researcheres are studied how preparing fine grain SAPO-34 molecular sieve, such as: Liu red magnitude [Liu Hong Star, etc., catalysis journal, 2004,25 (9): 702-706；Liu Hongxing, etc., catalysis journal, 2003,24 (4): 279-283] pass through Use HF-TEA or TEAOH-C4H9NO double template, obtain the SAPO-34 molecular sieve that mean diameter is 1.7 μm, this knot It is template that fruit is substantially better than single TEA or C4H9NO of employing；[Hendri van H., the Svetlana M. such as Hendri Thomas B. Chem. Mater., 2008,20:2956-2963] employing TEAOH is template, controls the addition of phosphoric acid Speed, and it is prepared for the particle diameter SAPO-34 molecular sieve less than 300 nm by microwave attenuation materials method；Norikazu etc. [Norikazu N., Masumi K., Yuichiro H., et al. Applied Catalysis A:General, 2009,362:193-199] mixture being respectively adopted TEAOH, Mor, TEEDA, TEAOH and Mor is template, synthesizes Particle diameter is the SAPO-34 molecular sieve of 800 nm.

The research of Yuan Zhongyong etc. [CN 101462742,2009] finds that using triethylamine is template, is fluorinated by interpolation Thing (such as sodium fluoride, ammonium fluoride or fluohydric acid gas), particularly ammonium fluoride, the crystallite dimension of product can be significantly reduced, optimum can obtain SAPO-34 molecular sieve to 1.4 μm；Li Wei etc. [CN 101214974,2008] are on the basis of conventional hydrothermal synthetic method, logical Crossing introducing ultrasonic disperse in initial gel mixture whipping process, the SAPO-34 zeolite crystal size obtained is closed than routine Become to reduce 50 %.

Hole dawn etc. [hole dawn, Liu Xiaoqin, Liu Dinghua, Institutes Of Technology Of Nanjing's journal, 2007,31(4): 528-532] Research also demonstrates ultrasonic disperse effect in fine grain SAPO-34 molecular sieve synthesizes, and they are right with triethylamine as template The most static crystallization after Primogel supersound process 0.5 h, can be decreased to 1.2 μm by crystal grain mean size by 2.9 μm.

Visible, existing document and patent report are mainly by changing the kind of template and consumption, in synthetic system Add auxiliary agent or introduce the next SAPO-34 molecular sieves that can obtain less crystal grain such as ultrasound field.These researchs are to a certain extent Enrich the preparation method of fine grain SAPO-34 molecular sieve, yet with specific template agent, auxiliary agent or the use of medium field, Limit industrial applications to varying degrees, the fine grain SAPO-34 molecular sieve preparation side that development approach is simple, the suitability is strong Method can preferably solve this problem.

Summary of the invention

The technical problem to be solved is prior synthesizing method gained bigger the asking of SAPO-34 zeolite crystal Topic, it is provided that the fine grain SAPO-34 molecular sieve preparation method that a kind of method is simple, the suitability is strong.SAPO-34 prepared by the method It is less that molecular sieve has crystallite dimension, the feature of homogeneous grain size.

For solving above-mentioned technical problem, the technical solution used in the present invention is as follows: one prepares fine grain SAPO-34 molecule The method of sieve, comprises the following steps:

A) phosphorus source, aluminum source, silicon source, template and water are configured to synthesize the initial crystallization liquid I of SAPO-34 molecular sieve, just In beginning crystallization liquid I, the molar ratio range of each component is as follows: template: SiO₂:Al₂O₃:P₂O₅:H₂The mol ratio of O is (1 ~ 5): (0.05~2):(0.5~3):(0.5~3): (20~200)；

B) initial crystallization liquid I is stirred aging 1 ~ 24 h at 10 ~ 80 DEG C, obtain aging after crystallization liquid II；

C) crystallization liquid II after aging is put into crystallizing kettle, hydrothermal crystallizing 1 ~ 10 h at 200 ~ 250 DEG C；

D) separate hydrothermal crystallizing gained solid product, obtain the crystal seed with defect sturcture；

E) by the material rate preparation crystallization liquid III of step a), with SiO contained in crystallization liquid III₂Weight meter, add 0.1 ~ In 50 % step d), gained has the crystal seed of defect sturcture, obtains crystallization liquid IV；

F) according to the method for step b), crystallization liquid IV is carried out aging, obtain aging after crystallization liquid V；

G) crystallization liquid V after aging is loaded crystallizing kettle, be warming up to 140 ~ 170 DEG C, and keep 0.1 ~ 4 h；

H) 180 ~ 250 DEG C it are warming up to, hydrothermal crystallizing 2 ~ 36 h；

I) reclaim product, obtain fine grain SAPO-34 molecular sieve.

In technical scheme, aluminum source preferred version is selected from aluminum isopropylate., boehmite or aluminium oxide extremely Few one；At least one in phosphoric acid, phosphate or phosphorous acid of phosphorus source preferred version；Silicon source preferred version is selected from At least one in TEOS, white carbon or Ludox；Template preferred version selected from TEAOH, TPA, triethylamine, diethylamine or At least one in morpholine；In step c), the preferred scope of hydrothermal crystallizing temperature is 200 ~ 250 DEG C, and more preferably scope is 210 ~ 240 ℃；In step c) hydrothermal crystallizing time preferred scope be 1 ~ 10 h, more preferably scope be 2 ~ 8 h；Defect sturcture described in step e) The preferred scope of crystal seed additional proportion is that 0.1 ~ 50 %(is with SiO contained in crystallization liquid₂Weight meter), more preferably scope is 1 ~ 10 %； In step g), the preferred scope for the treatment of temperature is 150 ~ 170 DEG C, and more preferably scope is 150 ~ 160 DEG C；Step f) processes the time Preferably scope be 0.2 ~ 4 h, more preferably scope be 0.5 ~ 2 h；Step h) the preferred scope of hydrothermal crystallizing temperature is 180 ~ 240 DEG C, More preferably scope is 190 ~ 240 DEG C, the preferred scope of crystallization time be 3 ~ 36 h, more preferably scope be 8-24 h；Institute in step h) Obtain a fine grain SAPO-34 molecular sieve at least crystal grain and be not more than 1 micron.

Preferably technical scheme, in step i), gained fine grain SAPO-34 molecular sieve grain size is 100-800nm.Step Rapid b) with in step f), aging condition is for stir aging 5 ~ 20 h at 40 ~ 70 DEG C.

Adding finished product molecular sieve crystal seed of the same race in Zeolite synthesis system is relatively common a kind of technological means, as specially Profit CN101555024 with the addition of finished product SAPO-34 molecular screen primary powder as solid-state crystal seed in building-up process, its result of study table The addition of bright solid-state crystal seed serves induction SAPO-34 molecular sieve and generates, reduces the effect of template consumption.But we note that Arriving, this institute obtains the crystallite dimension of zeolite product and there is no and be obviously reduced, this is because finished product molecular sieve solid-state used by it is brilliant The crystallite dimension planted is the biggest, and crystallizes perfection, thus can not effectively play the effect providing a large amount of tiny nucleus.

Synthetic system can play structure directing it is known that same molecules sieve crystal seed adds to and growth nucleus is provided The effect of two aspects, the SAPO-34 zeolite product little and homogeneous in order to obtain crystallite dimension, provide a large amount of for synthetic system The tiny nucleus with SAPO-34 structure is one of effective method, but the tiny SAPO-34 nucleus of size is difficult to system Standby and the most tiny crystal grain is the most also difficult to solid-liquid separation, thus in research in the past, crystal seed used mostly is brilliant The finished product SAPO-34 molecular sieve that particle size is bigger, the technical program solves this difficult problem the most well.

Based on the result of study to Crystallization of Zeolite course, the technical program by controlling suitable hydrothermal synthesizing condition, Gained crystal seed is the nascent crystals at crystallization course initial stage, and this nascent crystals granule is bigger, it is easy to solid-liquid separation, is different from into especially Product molecular sieve is that it exists a large amount of lattice defect, is the loose crystal of structure comparison.This nascent crystals addition SAPO-34 is divided Son sieves initial crystallization liquid and after hydrothermal treatment consists 0.5 ~ 2 h at 140 ~ 170 DEG C, there is the nascent crystals knot of a large amount of lattice defect Structure caves in, and dissolves with fine pieces form, obtains providing SAPO-34 structure directing and the crystalline substance of tiny nucleation in a large number Kind, then it being warming up to the crystallization temperature of 180 ~ 250 DEG C, synthetic system mushrooms out as crystal grain chi under the effect of tiny nucleus Very little it is obviously reduced, the SAPO-34 zeolite product that grain size is homogeneous.

Comparative study result shows, if using the perfect finished product molecular sieve of crystallization as crystal seed, it is main It is the dissolving recrystallization process of crystal-raw material-crystal, thus the work producing tiny nucleus in the technical program cannot be realized With.As a example by using the triethylamine synthetic system as template, the average particle diameter size of the obtained product of Traditional Method is that 3.5 μm are left The right side, adds the 5 made crystal seeds of % this method, and crystallization, the crystallite dimension of final products again after hydrothermal treatment consists 1 h at 160 DEG C 1.7 μm can be decreased to.Through MTO catalysis examination, the SAPO-34 zeolite product of little crystal grain has excellent catalytic performance, diene Yield and anticoking capability are all obviously improved.

Accompanying drawing explanation

Fig. 1 is the scanning electron microscopic picture of the SAPO-34 molecular sieve of comparative example 1 synthesis.

Fig. 2 is the scanning electron microscopic picture of the SAPO-34 molecular sieve of embodiment 1 synthesis.

Below by embodiment, the invention will be further elaborated, but is not limited only to the present embodiment.

Detailed description of the invention

[comparative example 1]

12.1 g γ-Al₂O₃Solution a is formed with 35.0 g deionized water mix homogeneously；23.3 g orthophosphoric acid (85% weights Amount), 37.5 g deionized water mix homogeneously formed solution b；A with b is stirred at room temperature 2 H-shapeds after mixing and becomes uniform solution c； It is kept stirring for, in c, is sequentially added into 31.0 g triethylamines, 4.5 g Ludox and 27.0 g deionized waters, obtains after being sufficiently stirred for The initial crystallization liquid of synthesis SAPO-34 molecular sieve；The crystallization liquid prepared is stirred at 25 DEG C ageing 24 h, has been aged Crystallization liquid loads with in teflon-lined crystallizing kettle, hydrothermal crystallizing 24 h at 200 DEG C；Products therefrom is scrubbed, Centrifugal, 110 DEG C dry to obtain solid sample, XRD result shows, products obtained therefrom is SAPO-34 molecular sieve, average grain size 3.5 μm (see figure 1).

Will sample be checked and rated roasting 5 h at 550 DEG C, obtain SAPO-34 molecular sieve powder, through tabletting, be ground into 20-40 mesh granule, checks and rates for MTO catalytic performance.The stainless steel tube that evaluation device uses Φ 12 mm wall thickness to be 1 mm is made Fixed bed reactors, apparatus with catalyst inside 2.0 g, product analyzes gas with Agilent 6890N chromatograph after gas-liquid separation Phase product forms.

The catalysis appraisal result that MTO is reacted by comparative sample S0 shows, when reaction proceeds to 30 min, and its diene (second Alkene+propylene) selectivity reaches high point, is 80.2 %.

[embodiment 1]

The initial crystallization liquid of preparation identical with comparative example 1, this crystallization liquid in crystallizing kettle at 220 DEG C crystallization 4 h, gained Product by centrifugation, wash to obtain solid crystal seeds；Again prepare initial crystallization liquid, and add 5 %(with SiO contained in crystallization liquid₂Weight Meter) before preparation solid crystal seeds, load crystallizing kettle, be warming up to 160 DEG C, and keep 1 h；Then 200 DEG C it are warming up to, crystallization 24 h；Products therefrom is scrubbed, centrifugal, 110 DEG C dry to obtain solid sample, XRD result shows, products obtained therefrom is that SAPO-34 divides Son sieve, average grain size 1.7 μm (see figure 2), the catalysis appraisal result of MTO reaction shows, proceeds to 40 min in reaction Time, its diene (ethylene+propylene) selectivity reaches high point, is 81.5 %.

[embodiment 2～5]

Identical with the operating procedure of embodiment 1 and experiment condition, only crystal seed additional proportion is different, gained sample average particle diameter It is shown in Table 1 with MTO catalytic result.

Table 1

[embodiment 6]

The initial crystallization liquid of preparation identical with comparative example 1, this crystallization liquid in crystallizing kettle at 240 DEG C crystallization 2 h, gained Product by centrifugation, wash to obtain solid crystal seeds；Again prepare initial crystallization liquid, and add 5 %(with SiO contained in crystallization liquid₂Weight Meter) solid crystal seeds, load crystallizing kettle, be warming up to 150 DEG C, and keep 2 h；Then 220 DEG C it are warming up to, crystallization 12 h；Institute Product scrubbed, centrifugal, 110 DEG C dry to obtain solid sample, XRD result shows, products obtained therefrom is SAPO-34 molecular sieve, put down All crystallite dimension 1.2 μm, the catalysis appraisal result of MTO reaction shows, when reaction proceeds to 50 min, its diene (ethylene+ Propylene) selectivity reaches high point, is 82.9 %.

[embodiment 7]

The initial crystallization liquid of preparation identical with comparative example 1, this crystallization liquid in crystallizing kettle at 200 DEG C crystallization 6 h, gained Product by centrifugation, wash to obtain solid crystal seeds；Again prepare initial crystallization liquid, and add 8 %(with SiO contained in crystallization liquid₂Weight Meter) solid crystal seeds, load crystallizing kettle, be warming up to 150 DEG C, and keep 2 h；Then 200 DEG C it are warming up to, crystallization 16 h；Institute Product scrubbed, centrifugal, 110 DEG C dry to obtain solid sample, XRD result shows, products obtained therefrom is SAPO-34 molecular sieve, put down All crystallite dimension 1.6 μm, the catalysis appraisal result of MTO reaction shows, when reaction proceeds to 40 min, its diene (ethylene+ Propylene) selectivity reaches high point, is 81.6 %.

[embodiment 8]

Identical with the operating procedure of embodiment 1 and experiment condition, only change initial crystallization liquid proportioning raw materials, wherein three second Amine: 51.7 g；Ludox: 15.0 g；γ-Al₂O₃: 6.1 g；Orthophosphoric acid: 11.7 g.Products obtained therefrom is SAPO-34 molecular sieve, Average grain size 1.5 μm, the catalysis appraisal result of MTO reaction shows, when reaction proceeds to 45 min, its diene (ethylene + propylene) selectivity reaches high point, is 81.7 %.

[embodiment 9]

Preparation crystallization liquid identical with comparative example 1, but template used dose of triethylamine and phosphoric acid are stoichiometrically replaced by TEAOH and phosphorous acid.Same as in Example 1 prepare crystal seed, by 8 %(with SiO contained in crystallization liquid₂Weight meter) crystal seed add The aforementioned crystallization liquid prepared, loads crystallizing kettle, is warming up to 150 DEG C, and keeps 2 h；Then 200 DEG C it are warming up to, crystallization 16 h；Products therefrom is scrubbed, centrifugal, 110 DEG C dry to obtain solid sample, XRD result shows, products obtained therefrom is SAPO-34 molecule Sieve, its particle diameter is at least less than 200 nm in a dimension.

Claims

1. the method preparing fine grain SAPO-34 molecular sieve, comprises the following steps:

A) phosphorus source, aluminum source, silicon source, template and water are configured to synthesize the initial crystallization liquid I of SAPO-34 molecular sieve, initially brilliant Change the mol ratio of each component in liquid I as follows:

Template: SiO₂:Al₂O₃:P₂O₅:H₂The mol ratio of O is (1～5): (0.05～2): (0.5～3): (0.5～3): (20 ～200)；

B) initial crystallization liquid I is stirred aging 1～24h at 10～80 DEG C, obtain aging after crystallization liquid II；

C) crystallization liquid II after aging is put into crystallizing kettle, at 200～250 DEG C, hydrothermal crystallizing 1～10h；

E) by the material rate preparation crystallization liquid III of step a), with SiO contained in crystallization liquid III₂Weight meter, addition 1～10% step In d), gained has the crystal seed of defect sturcture, obtains crystallization liquid IV；

G) crystallization liquid V after aging is loaded crystallizing kettle, be warming up to 140～170 DEG C, and keep 0.1～4h；

H) 190～240 DEG C it are warming up to, hydrothermal crystallizing 8～24h；

I) reclaim product, obtain fine grain SAPO-34 molecular sieve.

2. according to the method preparing fine grain SAPO-34 molecular sieve described in claim 1, it is characterised in that aluminum source is selected from isopropanol At least one in aluminum, boehmite or aluminium oxide；At least one in phosphoric acid, phosphate or phosphorous acid of phosphorus source； At least one in TEOS, white carbon or Ludox of silicon source；Template selected from TEAOH, TPA, triethylamine, diethylamine or At least one in morpholine.

3. according to the method preparing fine grain SAPO-34 molecular sieve described in claim 1, it is characterised in that in step c), hydro-thermal is brilliant Changing temperature is 210～240 DEG C, and the hydrothermal crystallizing time is 2～8h.

4. according to the method preparing fine grain SAPO-34 molecular sieve described in claim 1, it is characterised in that step g) is warming up to 150～160 DEG C, and keep 0.5～2h.

5. according to the method preparing fine grain SAPO-34 molecular sieve described in claim 1, it is characterised in that in step i), gained is little A crystal-size SAPO-34 zeolite at least crystal grain is not more than 1 micron.

6. according to the method preparing fine grain SAPO-34 molecular sieve described in claim 1, it is characterised in that in step i), gained is little Crystal-size SAPO-34 zeolite grain size is 100-800nm.

7. according to the method preparing fine grain SAPO-34 molecular sieve described in claim 1, it is characterised in that step b) and step f) In, aging condition is for stir aging 5～20h at 40～70 DEG C.