CN104525250A - SAPO-34 molecular sieve based catalyst of hierarchical pore structure and preparation and application thereof - Google Patents

Abstract

The invention discloses an SAPO-34 molecular sieve based catalyst of a hierarchical pore structure and preparation and application of the SAPO-34 molecular sieve based catalyst. The SAPO-34 molecular sieve based catalyst is prepared through the following steps that an aluminum source, a silicon source, a phosphorus source, triethylamine and water are mixed to form mixed liquor according to the molar ratio of 1 Al2O3 : (0.05-0.6) SiO2 : (0.8-1.2) P2O5 : (0.2-5) triethylamine : (5-100) H2O, a pre-crushed SAPO-34 molecular sieve is added and serves as a seed crystal, the mixture is crystallized, separated, washed, dried and calcinated, alkali treatment is conducted on a calcinated product, and then the SAPO-34 molecular sieve based catalyst of the hierarchical pore structure is obtained. The catalyst is applied to methanol to olefin reactions. The pore canal distribution of the catalyst is orderly, and the catalyst has the advantages of being good in repeatability, high in activity and low carbon olefin selectivity and the like in the MTO reactions.

Description

The SAPO-34 molecular sieve catalyst of hierarchical porous structure and Synthesis and applications thereof

Technical field

The present invention relates to a kind of catalyst and Synthesis and applications thereof, particularly relate to a kind of SAPO-34 molecular sieve catalyst and Synthesis and applications thereof of hierarchical porous structure.

Background technology

China's coal-mine rich reserves, ammonia from coal device is gone into operation in a large number.Cut-off was to 2010, and the annual methyl alcohol aggregated capacity of China has reached 3,500 ten thousand tons, and output approximately only has 1,500 ten thousand tons, has occurred serious production capacity surplus, therefore develops Downstream Products of Methanol and has great importance to methanol industry.In numerous Downstream Products of Methanol transformation technology, preparing light olefins from methanol (MTO, Methanolto Olefin) development of technology, by economic competitiveness and the resource utilization of developing skill further, to performance coal resources in China advantage, alleviate the nervous situation of Chinese petroleum corporation, there is Great significance and strategic importance.

In numerous MTO catalyst, aluminium silicophosphate (SAPO) molecular sieve has suitable Bronsted acidity, special pore passage structure, larger specific area, preferably absorption property and good heat endurance and hydrothermal stability etc. due to it, make it in numerous catalytic reaction, show excellent reactivity worth, as SAPO-34 molecular sieve is applied in MTO reaction, present good catalytic activity and selectivity of light olefin.But because its duct is little, product is not easy to spread out, easily there is secondary response and carbon distribution, cause rapid catalyst deactivation, make SAPO molecular sieve in commercial Application, need frequent regeneration, add energy consumption cost.

For SAPO-34 rapid deactivation problem, researchers attempt introducing mesoporous and macropore in micro porous molecular sieve to increase external surface area and the duct openness of molecular sieve, thus obtain the SAPO-34 molecular sieve of hierarchical porous structure.This multi-stage porous molecular sieve not only has abundant micropore, enough specific areas and reaction site can be provided for reaction, also there is enough mesoporous and macropores simultaneously, for reactant and product provide the passage of fast transport, effectively can reduce the carbon distribution problem of SAPO-34 in course of reaction.There are reports in the synthesis of multi-stage porous SAPO-34, and patent CN101121533A adopts in-situ synthesis, add diethylamine, n-propylamine etc. and obtain and have micropore and mesoporous SAPO-34, but the method do not obtain macropore duct in synthesized gel rubber; In patent CN102219236A, CN102219237A and CN102219629A, by the special organic solvent that induces one in Primogel, as polyoxyethylene, glycidol ether or oxolane etc., multi-stage porous SAPO-34 molecular sieve can be formed, this molecular sieve methanol-to-olefins (MTO) reaction in show higher yield of light olefins, but organic solvent make this molecular sieve cost higher; The people such as Wang Chan adopt organic silicon surfactant octadecyldimethyl [the 3-trimethoxy silicon propyl group] ammonium chloride (TPHAC) of amphiphilic as part silicon source and mesoporous template, using tetraethyl ammonium hydroxide as micropore template, Hydrothermal Synthesis multi-stage porous SAPO-34 molecular sieve, but the pattern irregularity of this molecular sieve, and gained molecular sieve does not have reaction evaluating data yet; L.Wu etc. adopt chlorination octadecyl ammonium (TPOAC) and C _22-4-4br ₂for mesoporous template has synthesized multi-stage porous SAPO-34 molecular sieve, but mesoporous template causes the acidic site of molecular sieve to reduce in a large number, when being MTO catalyst with it, feed stock conversion with single pass life lower than traditional SAPO-34 molecular sieve; Y.Li etc. by controlling the quantity of silicon atom in mother liquor, and step Hydrothermal Synthesis multi-stage porous SAPO-34/18 molecular sieve, but do not obtain the SAPO-34 of single thing phase, in MTO reaction, methanol conversion is also less than 20%.With the micropore SAPO-34 molecular sieve that acid treatment is traditional in patent CN102923727A, the SAPO-34 molecular sieve with micropore, mesoporous and macropore is obtained by optimization for the treatment of conditions, and higher yield of light olefins is shown in MTO process, but this patent concentrates on and adopts various acid to carry out treatment S APO-34 molecular sieve to obtain multi-stage porous molecular sieve, do not relate to the impact of the process of chemical bases.Because acid treatment process relate generally to Al in SAPO-34 remove produce mesoporous, and alkali treatment process relates to removing of Si and Al simultaneously, the latter will produce more profound influence to SAPO-34 molecular sieve pore passage and acidic character, the two manufactures the difference in mesoporous mode, the selectivity of light olefin in MTO process and catalyst life will be affected, but also there is no the system research of this respect at present.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of SAPO-34 molecular sieve catalyst and Synthesis and applications thereof of hierarchical porous structure.This catalyst has hierarchical porous structure, and has preparation method is simple, can be used for the advantages such as methanol-to-olefins (MTO) long-life, high-performance catalyst.

For solving the problems of the technologies described above, the SAPO-34 molecular sieve catalyst of hierarchical porous structure, it is prepared by following methods:

Be 1Al in molar ratio ₂o ₃: (0.05 ~ 0.6) SiO ₂: (0.8 ~ 1.2) P ₂o ₅: (0.2 ~ 5) triethylamine (TEA): (5 ~ 100) H ₂ratio (the i.e. Al of O ₂o ₃: SiO ₂: P ₂o ₅: triethylamine: H ₂mol ratio=1:(0.05 ~ 0.6 of O): (0.8 ~ 1.2): (0.2 ~ 5): (5 ~ 100)), aluminium source, silicon source, phosphorus source, template triethylamine and water are made into mixed liquor, and the SAPO-34 molecular sieve adding fragmentation is in advance crystal seed, crystallization, is separated, washing, dry, roasting, and alkali treatment is carried out to the product after roasting, obtain the SAPO-34 molecular sieve catalyst of hierarchical porous structure.

The crystal grain of described catalyst is cubic, and the multi-stage porous duct of the visible regular distribution in surface, pore-size distribution is between 0.3 ~ 300nm, and BET specific surface area is 300 ~ 700m ²/ g.

In addition, the present invention also provides the detailed preparation method of above-mentioned catalyst, comprises step:

1) be 1Al in molar ratio ₂o ₃: (0.05 ~ 0.6) SiO ₂: (0.8 ~ 1.2) P ₂o ₅: (0.2 ~ 5) triethylamine: (5 ~ 100) H ₂the ratio of O, aluminium source, silicon source, phosphorus source, template triethylamine and water are made into mixed liquor, and the SAPO-34 molecular sieve adding fragmentation is in advance crystal seed, crystallization 2 ~ 100 hours at 130 ~ 200 DEG C, product, after separation, washing, drying and roasting, obtains the 2nd SAPO-34 molecular sieve;

2) by step 1) the 2nd SAPO-34 molecular sieve of gained mixes with alkali;

3) by step 2) mixture of gained stir process after 0.1 ~ 150 hour at 20 ~ 100 DEG C, through being separated, dry, obtain the SAPO-34 molecular sieve catalyst of hierarchical porous structure.

Described step 1) in, aluminium source comprises: sodium metaaluminate, boehmite, aluminium hydroxide, aluminium isopropoxide, aluminium nitride, aluminium sulfide or aluminium powder and other common Zeolite synthesis aluminium sources;

Silicon source comprises: Ludox, white carbon, methyl silicate, ethyl orthosilicate or waterglass and other common Zeolite synthesis silicon sources;

Phosphorus source comprises: phosphoric acid, metaphosphoric acid or ammonium dihydrogen phosphate (ADP) and other common Zeolite synthesis phosphorus sources;

The addition of a described SAPO-34 molecular sieve preferably accounts for step 1) in mixed liquor gross mass 0.1 ~ 5%, more preferably account for step 1) in mixed liquor gross mass 0.2 ~ 3%; In addition, a described SAPO-34 molecular sieve can refer to CN102923727A and is prepared; In addition, in a SAPO-34 molecular sieve broken in advance, a SAPO-34 molecular sieve need be crushed to particle and be less than 100 orders;

Described step 1) product through being separated, washing, concrete steps that are dry and roasting are: can be undertaken by the routine operation in molecular sieve art, but preferred product 400 ~ 600 DEG C of roastings 4 ~ 50 hours under suction filtration separation, water washing, 80 ~ 150 DEG C of dryings 4 ~ 100 hours and air atmosphere.

Described step 2) in, alkali comprises: one or more of NaOH, sodium carbonate, ammoniacal liquor, quaternary ammonium base, sodium oxalate etc.; Wherein, quaternary ammonium base comprises: one or more of TMAH (TMAOH), tetraethyl ammonium hydroxide (TEAOH), TPAOH (TPAOH), TBAH;

Preferably, alkali be NaOH, sodium carbonate, tetraethyl ammonium hydroxide (TEAOH) one or more;

Paper mill wastewater is preferably 0.01 ~ 10mo1/L; The weight ratio of the 2nd SAPO-34 molecular sieve and alkali is preferably 1:5 ~ 1:100; Wherein, more preferably, paper mill wastewater is 0.05 ~ 2mol/L, and the weight ratio of the 2nd SAPO-34 molecular sieve and alkali is 1:2 ~ 1:20.

Described step 3) in, as required, also can by step 2) mixture of gained stir process after 0.1 ~ 150 hour at 20 ~ 100 DEG C, through being separated, after dry and roasting, obtain the SAPO-34 molecular sieve catalyst of hierarchical porous structure.Described step 3) in, the temperature of stir process preferably 50 ~ 100 DEG C, preferably 0.5 ~ 48 hour processing time.

In addition, the present invention also provides the application of the SAPO-34 molecular sieve catalyst of above-mentioned hierarchical porous structure, as described in the application of catalyst in methanol to olefins reaction (MTO reaction), wherein, the optimum condition of described reaction is as follows:

Reaction temperature 350 ~ 600 DEG C, reaction pressure 0.1 ~ 2MPa, reaction velocity 0.1 ~ 20h ^-1, water and methyl alcohol weight ratio be 0 ~ 5.

In above-mentioned reaction, reaction unit is preferably fixed bed or fluidized-bed reactor.

In addition, preferred reaction condition is as follows further:

Reaction temperature 400 ~ 500 DEG C, reaction pressure 0.1 ~ 0.8MPa, reaction velocity 0.5 ~ 4h ^-1, water is 0 ~ 4 with methanol weight ratio.

The SAPO-34 molecular sieve catalyst of hierarchical porous structure of the present invention is the SAPO-34 molecular sieve by first synthesizing specific composition, then carries out alkali treatment to it again and obtains.Be different from other soda acid post-processing catalyst, this catalyst relative crystallinity and untreated SAPO-34 molecular sieve ratio, it does not lose, and stereoscan photograph clearly can be seen the different mesoporous or macropore of pattern, distribution, size; In addition, the pore distribution of catalyst of the present invention is very regular.

In addition, catalyst of the present invention has reproducible, the high and low carbon olefin (C of catalyst activity in MTO reaction ₂-C ₄alkene) selective advantages of higher; As on catalyst of the present invention, methyl alcohol can be converted into alkene by a step, and the single pass life of this catalyst is long, the selective height of alkene.Particularly when reaction temperature be 400 ~ 500 DEG C, feed space velocity is 0.5 ~ 4h ^-1time, methanol conversion higher than 99% time, in product, selectivity of light olefin is higher than 90%, and the single pass life of fixed bed reactors, more than 300 minutes, is 2 ~ 3 times of conventional SAPO-34 molecular sieve catalyst.

Accompanying drawing explanation

Below in conjunction with accompanying drawing and detailed description of the invention, the present invention is further detailed explanation:

Fig. 1 is XRD (X-ray diffraction) spectrogram that the embodiment of the present invention 1 and embodiment 21 prepare product.

Fig. 2 is the embodiment of the present invention 1 step 1) prepare SEM (SEM) figure of product.

Fig. 3 is the embodiment of the present invention 1 step 2) prepare product SEM figure.

Fig. 4 is the SEM figure that the embodiment of the present invention 7 prepares product.

Fig. 5 is the SEM figure that the embodiment of the present invention 12 prepares product.

Fig. 6 is the SEM figure that the embodiment of the present invention 14 prepares product.

Fig. 7 is the SEM figure that the embodiment of the present invention 17 prepares product.

Detailed description of the invention

In following examples, the reagent related to if not otherwise specified, is commercially produced product (" water " mentioned as following is deionized water, and reagent is pure for analyzing, and concrete consumption is shown in embodiment) then.

In addition, the SAPO-34 molecular sieve related in following examples is prepared with reference to CN102923727A.

Embodiment 1

The synthesis of the SAPO-34 molecular sieve catalyst of hierarchical porous structure completes in two steps:

Step 1), be 1Al in molar ratio ₂o ₃: 0.44SiO ₂: 1.1P ₂o ₅: 2.25TEA:35H ₂the ratio of O, by boehmite (Al ₂o ₃mass fraction be 64%), Ludox (SiO ₂mass concentration be 30%), SPA (mass concentration is 85%), triethylamine (TEA) and water is mixed into gel, and add the prior grinding accounting for this gel gross weight 0.1% and be crushed to particle and be less than 100 objects the one SAPO-34 molecular sieve as crystal seed, then colloidal sol is inserted in reactor, dynamically in lower 7 hours from room temperature to 165 DEG C, then be incubated 33 hours to carry out crystallization.Product is separated through suction filtration, washing (as washing with water), after dry and roasting (as 550 DEG C of roastings 6 hours under 100 DEG C of dryings 6 hours and air atmosphere), obtain the 2nd SAPO-34 molecular sieve, its XRD spectra is shown in Fig. 1, and SEM figure is shown in Fig. 2.As can be seen from Figure 1, the diffraction peak intensity of the 2nd SAPO-34 sieve sample is very high, meets completely, and occur without other diffraction maximums with SAPO-34 zeolites spectrogram, illustrates that what obtain is the SAPO-34 molecular sieve of high relative crystallinity.In addition, Fig. 2 shows that gained the 2nd SAPO-34 molecular sieve has cube looks, and any surface finish is smooth, can't see mesoporous existence.

Step 2), get 5 grams of steps 1) in after the 2nd SAPO-34 molecular sieve of gained mixes with the NaOH solution of 100 grams of 0.5mo1/L (being abbreviated as 0.5M), stir process 2 hours at 90 DEG C, separating obtained solid is again after the washing of routine, drying and roasting, obtain the SAPO-34 molecular sieve catalyst of hierarchical porous structure, its SEM figure is shown in Fig. 3, as can be seen from the figure originally bright and clean cube face occurred mesoporous category, duct in butterfly-like distribution, together with micropore originally, constitute the SAPO-34 molecular sieve of hierarchical porous structure.

Embodiment 2-4

According to the method in embodiment 1, in step 2) in, by 5 grams of steps 1) in the 2nd SAPO-34 molecular sieve of gained mix with the NaOH solution of 30 grams of 0.5mo1/L, gained mixture is processed 6,20 and 50 hours at 60 DEG C, other conditions are constant, obtain embodiment 2 ~ 4.

Embodiment 5-8

According to the method in embodiment 1, in step 2) in, by 5 grams of steps 1) in the 2nd SAPO-34 molecular sieve of gained mix with the NaOH solution of 500 grams of 0.05mo1/L, gained mixture is processed 10,50,100 and 150 hours at 30 DEG C, and other conditions are constant, obtain example 5 ~ 8, the SEM figure of embodiment 7 is shown in Fig. 4, as can be seen from Figure 4, cube face has occurred that some are less mesoporous, illustrates and defines multi-stage porous SAPO-34 molecular sieve to a certain extent.

Embodiment 9-12

According to the method in embodiment 1, in step 2) in, by 5 grams of steps 1) in the 2nd SAPO-34 molecular sieve of gained and the Na of 50 grams of 1mo1/L ₂cO ₃solution mixes, and gained mixture is processed 2,10,20 and 50 hours at 50 DEG C, and other conditions are constant, obtain example 9 ~ 12, the SEM figure of embodiment 12 is shown in Fig. 5, and as can be seen from Figure 5, cube face occurs mesoporous, illustrates and defines multi-stage porous SAPO-34 molecular sieve.

Embodiment 13-15

According to the method in embodiment 1, in step 2) in, by 5 grams of steps 1) in the 2nd SAPO-34 molecular sieve of gained mix with the TEAOH solution of 50 grams of 1mo1/L, gained mixture is processed 2,6 and 10 hours at 90 DEG C, and other conditions are constant, obtain example 13 ~ 15, the SEM figure of embodiment 14 is shown in Fig. 6, as can be seen from Figure 6, cube face has occurred that some are larger mesoporous, illustrates and defines multi-stage porous SAPO-34 molecular sieve.

Embodiment 16-17

According to the method in embodiment 1, in step 2) in, by 5 grams of steps 1) in the 2nd SAPO-34 molecular sieve of gained mix with the ammonia spirit of 400 grams of 1mo1/L, gained mixture is processed 2 and 10 hours at 90 DEG C, and other conditions are constant, obtain example 16 ~ 17, the SEM figure of embodiment 17 is shown in Fig. 7, and as can be seen from Figure 7, cube face has occurred that some are mesoporous, explanation defines multi-stage porous SAPO-34 molecular sieve, but it is even not to there is mesoporous crystal grain distribution.

Embodiment 18-20

According to the method in embodiment 16, in step 2) in, by 5 grams of steps 1) in the 2nd SAPO-34 molecular sieve of gained mix with the ammonia spirit of 100 grams of 10mo1/L, gained mixture is processed 0.2,1 and 5 hour at 20 DEG C, other conditions are constant, obtain example 18 ~ 20.

Embodiment 21

The synthesis of the SAPO-34 molecular sieve catalyst of hierarchical porous structure completes in two steps:

Step 1), be 1Al in molar ratio ₂o ₃: 0.2SiO ₂: 1.0P ₂o ₅: 5.0TEA:80H ₂the ratio of O, boehmite, Ludox, SPA, triethylamine and water are mixed into gel, and add in advance grinding in the ratio accounting for this gel gross weight 3% and be crushed to particle and be less than 100 objects the one SAPO-34 molecular sieve crystal seed, then colloidal sol is inserted in reactor, dynamically within lower 4 hours, be warming up to 165 DEG C, be incubated 100 hours again, to carry out crystallization.Product is separated through the suction filtration of routine, wash (as washing with water), after dry (as 120 DEG C of dryings 20 hours) and roasting (as 500 DEG C of roasting 20h), obtain the 2nd SAPO-34 molecular sieve.

Step 2), get 5 grams of steps 1) in after the 2nd SAPO-34 molecular sieve of gained mixes with the NaOH solution of 100 grams of 0.5mo1/L (being abbreviated as 0.5M), stir process 2 hours at 90 DEG C, separating obtained solid is again after the washing of routine, drying and roasting, obtain the SAPO-34 molecular sieve catalyst of hierarchical porous structure, its XRD spectra is shown in Fig. 1.

Embodiment 22

By the SAPO-34 molecular sieve catalyst of gained hierarchical porous structure in embodiment 1, after compressing tablet, sieve gets 20-40 object particle, methanol to olefins reaction (MTO reaction) is carried out in fixed bed reactors, wherein, reaction temperature is 400 DEG C, reaction pressure is 0.1MPa, and reaction velocity is 1h ^-1, the weight ratio of water and methyl alcohol is 1.The results are shown in Table 1.

Embodiment 23 ~ 24

By the SAPO-34 molecular sieve catalyst of gained hierarchical porous structure in embodiment 1, after compressing tablet, sieve gets 20-40 object particle, and in fixed bed reactors, carry out methanol to olefins reaction, wherein, reaction pressure is 0.1MPa, and reaction velocity is 1h ^-1, the weight ratio of water and methyl alcohol is 1, and reaction temperature is respectively 450 DEG C and 500 DEG C.The results are shown in Table 2 ~ 3.

Embodiment 25

By the SAPO-34 molecular sieve catalyst of gained hierarchical porous structure in embodiment 1, after compressing tablet, sieve gets 20-40 object particle, and in fixed bed reactors, carry out methanol to olefins reaction, wherein, reaction pressure is 0.3MPa, and reaction velocity is 4h ^-1, the weight ratio of water and methyl alcohol is 1, reaction temperature is 450 DEG C.The results are shown in Table 4.

Embodiment 26

By the SAPO-34 molecular sieve catalyst of gained hierarchical porous structure in embodiment 1, after compressing tablet, sieve gets 20-40 object particle, and in fixed bed reactors, carry out methanol to olefins reaction, wherein, reaction pressure is 0.5MPa, and reaction velocity is 10h ^-1, the weight ratio of water and methyl alcohol is 1, reaction temperature is 450 DEG C.The results are shown in Table 5.

Comparative example

Step 1 by embodiment 1) in gained SAPO-34 molecular sieve be catalyst, after compressing tablet, sieve get 20-40 object particle, in fixed bed reactors, carry out methanol to olefins reaction, wherein, reaction pressure is 0.1MPa, and reaction velocity is 1h ^-1, the weight ratio of water and methyl alcohol is 1, reaction temperature profile is 400,450 and 500 DEG C.The results are shown in Table 1 ~ 3.

Table 1 embodiment 22 and the comparative example catalyst performance in the MTO of 400 DEG C reacts

	Embodiment 22	Comparative example
			One way methanol of reaction conversion ratio more than 99% duration (min)	195	160
The duration of low-carbon alkene conversion ratio more than 85% (min)	310	120
			Ethylene selectivity (%)	36.41	34.15
Propylene Selectivity (%)	39.11	42.19
			Ethene and Propylene Selectivity sum (%)	75.52	76.34
The selective sum of ethene, propylene, butylene (%)	91.37	87.79

Note: each selective data in table 1 is that methanol conversion reaches 100%, low-carbon alkene (C ₂-C ₄alkene) total selection rate data that sample analysis obtains when reaching the highest.

Table 2 embodiment 23 and the comparative example catalyst performance in the MTO of 450 DEG C reacts

	Embodiment 23	Comparative example
			One way methanol of reaction conversion ratio more than 99% duration (min)	300	100
The duration of low-carbon alkene conversion ratio more than 85% (min)	410	180
			Ethylene selectivity (%)	50.32	48.09
Propylene Selectivity (%)	34.56	32.35
			Ethene and Propylene Selectivity sum (%)	84.88	80.44
The selective sum of ethene, propylene, butylene (%)	92.75	88.75

Note: each selective data in table 2 is that methanol conversion reaches 100%, low-carbon alkene (C ₂-C ₄alkene) total selection rate data that sample analysis obtains when reaching the highest.

Table 3 embodiment 24 and the comparative example catalyst performance in the MTO of 500 DEG C reacts

	Embodiment 24	Comparative example
			One way methanol of reaction conversion ratio more than 99% duration (min)	110	60
The duration of low-carbon alkene conversion ratio more than 85% (min)	165	130
			Ethylene selectivity (%)	55.07	55.92
Propylene Selectivity (%)	26.51	26.78
			Ethene and Propylene Selectivity sum (%)	81.58	82.70
The selective sum of ethene, propylene, butylene (%)	87.43	89.03

Note: each selective data in table 3 is that methanol conversion reaches 100%, low-carbon alkene (C ₂-C ₄alkene) total selection rate data that sample analysis obtains when reaching the highest.

The MTO reactivity worth of table 4 embodiment 25

One way methanol of reaction conversion ratio more than 99% duration (min)	165
		Ethylene selectivity (%)	29.38
Propylene Selectivity (%)	31.76
		Ethene and Propylene Selectivity sum (%)	61.14
The selective sum of ethene, propylene, butylene (%)	77.49

Note: each selective data in table 4 is that methanol conversion reaches 100%, low-carbon alkene (C ₂-C ₄alkene) total selection rate data that sample analysis obtains when reaching the highest.

The MTO reactivity worth of table 5 embodiment 26

One way methanol of reaction conversion ratio more than 99% duration (min)	125
		Ethylene selectivity (%)	13.95
Propylene Selectivity (%)	27.89
		Ethene and Propylene Selectivity sum (%)	41.84
The selective sum of ethene, propylene, butylene (%)	56.73

Note: each selective data in table 5 is that methanol conversion reaches 100%, low-carbon alkene (C ₂-C ₄alkene) total selection rate data that sample analysis obtains when reaching the highest.

In addition, the pore-size distribution of the SAPO-34 molecular sieve catalyst of hierarchical porous structure obtained in above-described embodiment is between 0.3 ~ 300nm, and BET specific surface area is 300 ~ 700m ²/ g.

Moreover, according to the result of table 1-5, take the SAPO-34 molecular sieve catalyst of the hierarchical porous structure obtained by this present invention, in MTO reaction, when reaction temperature be 400 ~ 500 DEG C, feed space velocity is 0.5 ~ 4h ^-1time, methyl alcohol can transform completely, illustrates that catalyst activity is high, and low-carbon alkene (C ₂-C ₄alkene) selective can up to 90%, particularly the single pass life of catalyst 450 DEG C time can reach 300min, 100 minutes that are significantly longer than traditional SAPO-34 catalyst.Significantly can reduce the frequency of catalyst regeneration in commercial Application in the future, reduce the operating cost of catalyst and improve the production capacity of low-carbon alkene, there is good application prospect.

Claims (10)

1. a SAPO-34 molecular sieve catalyst for hierarchical porous structure, is characterized in that, described catalyst is prepared by following methods:

Be 1Al in molar ratio ₂o ₃: 0.05 ~ 0.6SiO ₂: 0.8 ~ 1.2P ₂o ₅: 0.2 ~ 5 triethylamine: 5 ~ 100H ₂the ratio of O, is made into mixed liquor by aluminium source, silicon source, phosphorus source, triethylamine and water, and the SAPO-34 molecular sieve adding fragmentation is in advance crystal seed, crystallization, be separated, washing, dry, roasting, and alkali treatment is carried out to the product after roasting, obtain the SAPO-34 molecular sieve catalyst of hierarchical porous structure.

2. catalyst as claimed in claim 1, it is characterized in that: the crystal grain of described catalyst is cubic, the multi-stage porous duct of regular distribution is seen on surface, and pore-size distribution is between 0.3 ~ 300nm, and BET specific surface area is 300 ~ 700m ²/ g.

3. a preparation method for catalyst as claimed in claim 1 or 2, is characterized in that, comprises step:

1) be 1Al in molar ratio ₂o ₃: 0.05 ~ 0.6SiO ₂: 0.8 ~ 1.2P ₂o ₅: 0.2 ~ 5 triethylamine: 5 ~ 100H ₂the ratio of O, aluminium source, silicon source, phosphorus source, triethylamine and water are made into mixed liquor, and the SAPO-34 molecular sieve adding fragmentation is in advance crystal seed, crystallization 2 ~ 100 hours at 130 ~ 200 DEG C, product, after separation, washing, drying and roasting, obtains the 2nd SAPO-34 molecular sieve;

2) by step 1) the 2nd SAPO-34 molecular sieve of gained mixes with alkali;

3) by step 2) mixture of gained stir process after 0.1 ~ 150 hour at 20 ~ 100 DEG C, through being separated, dry, obtain the SAPO-34 molecular sieve catalyst of hierarchical porous structure.

4. method as claimed in claim 3, is characterized in that: described step 1) in, aluminium source comprises: sodium metaaluminate, boehmite, aluminium hydroxide, aluminium isopropoxide, aluminium nitride, aluminium sulfide or aluminium powder;

Silicon source comprises: Ludox, white carbon, methyl silicate, ethyl orthosilicate or waterglass;

Phosphorus source comprises: phosphoric acid, metaphosphoric acid or ammonium dihydrogen phosphate (ADP);

The addition of a described SAPO-34 molecular sieve accounts for step 1) in mixed liquor gross mass 0.1 ~ 5%;

A described SAPO-34 molecular sieve is prepared with reference to CN102923727A; In one SAPO-34 molecular sieve of prior fragmentation, a SAPO-34 molecular sieve need be crushed to particle and be less than 100 orders;

Described step 1) product through being separated, washing, concrete steps that are dry and roasting are: product 400 ~ 600 DEG C of roastings 4 ~ 50 hours under suction filtration separation, water washing, 80 ~ 150 DEG C of dryings 4 ~ 100 hours and air atmosphere.

5. method as claimed in claim 4, is characterized in that: the addition of a described SAPO-34 molecular sieve accounts for step 1) in mixed liquor gross mass 0.2 ~ 3%.

6. method as claimed in claim 3, is characterized in that: described step 2) in, alkali comprises: one or more of NaOH, sodium carbonate, ammoniacal liquor, quaternary ammonium base, sodium oxalate; Wherein, quaternary ammonium base comprises: one or more of TMAH, tetraethyl ammonium hydroxide, TPAOH, TBAH; Paper mill wastewater is 0.01 ~ 10mo1/L; The weight ratio of the 2nd SAPO-34 molecular sieve and alkali is 1:5 ~ 1:100;

Described step 3) in, the temperature of stir process is 50 ~ 100 DEG C, and the processing time is 0.5 ~ 48 hour.

7. method as claimed in claim 6, is characterized in that: described alkali be NaOH, sodium carbonate, tetraethyl ammonium hydroxide one or more;

Paper mill wastewater is 0.05 ~ 2mol/L, and the weight ratio of the 2nd SAPO-34 molecular sieve and alkali is 1:2 ~ 1:20.

8. method as claimed in claim 3, it is characterized in that: described step 3) in, also by step 2) mixture of gained stir process after 0.1 ~ 150 hour at 20 ~ 100 DEG C, through being separated, after dry and roasting, obtain the SAPO-34 molecular sieve catalyst of hierarchical porous structure.

9. an application for catalyst as claimed in claim 1 or 2, is characterized in that: the application of described catalyst in methanol to olefins reaction, and wherein, the condition of described reaction is as follows:

Reaction temperature 350 ~ 600 DEG C, reaction pressure 0.1 ~ 2MPa, reaction velocity 0.1 ~ 20h ^-1, water and methyl alcohol weight ratio be 0 ~ 5.

10. apply as claimed in claim 9, it is characterized in that: the reaction unit in described reaction is fixed bed or fluidized-bed reactor;

Reaction condition is as follows:

Reaction temperature 400 ~ 500 DEG C, reaction pressure 0.1 ~ 0.8MPa, reaction velocity 0.5 ~ 4h ^-1, water is 0 ~ 4 with methanol weight ratio.