SAPO-34/ZSM-5@ kaolin microsphere composite catalytic material and its preparation and use

Abstract

The present invention relates to a composite catalytic material of SAPO-34/ZSM-5@kaolin microspheres and its preparation and use, the method comprises the steps of: 1) processing kaolin into kaolin microspheres, and baking them to obtain activated kaolin microspheres; 2) mixing the activated kaolin microspheres obtained in step 1), water, a phosphorus source, and a template agent to prepare a gel; 3) mixing the gel obtained in step 2) and a ZSM-5 molecular sieve, and carrying out aging, crystallization, and separation to obtain a composite material of SAPO-34/ZSM-5@kaolin; 4) subjecting the composite material obtained in step 3) to ammonium exchange treatment and baking, to obtain the composite catalytic material of SAPO-34/ZSM-5@kaolin microspheres. The present invention not only greatly shortens the preparation route for the catalyst and reduces the cost of catalyst preparation, but also allows adjustment of the fractions of SAPO-34 and ZSM-5 molecular sieves in the composite material by adjustment of the synthesis conditions.

Claims

1. A method for preparing a composite catalytic material of SAPO-34/ZSM-5@kaolin microspheres, comprising the steps of: 1) processing kaolin into kaolin microspheres, and baking the kaolin microspheres to obtain activated kaolin microspheres comprising SiO.sub.2 and Al.sub.2O.sub.3; 2) mixing the activated kaolin microspheres obtained in step 1), water, a phosphorus source (P.sub.2O.sub.5), and a template agent, in a molar ratio of (4-6)R:(0.20-0.30)SiO.sub.2:(0.58-1.85)Al.sub.2O.sub.3:(2.0-3.1)P.sub.2O.sub.5:(111-222)H.sub.2O, to prepare a gel; 3) mixing the gel obtained in step 2) and a ZSM-5 molecular sieve, in a ZSM-5-to-gel mass ratio from 0.042 to 0.066, and carrying out aging, crystallization, and separation to obtain a composite material of SAPO-34/ZSM-5@kaolin; 4) subjecting the composite material obtained in step 3) to ammonium exchange treatment, and baking, to obtain the composite catalytic material of SAPO-34/ZSM-5@kaolin microspheres.

2. The method according to claim 1, wherein step 1) comprises processing kaolin into kaolin microspheres by spray drying and baking the kaolin microspheres to obtain activated kaolin microspheres having a particle size of 80 to 100 m.

3. The method according to claim 1, wherein step 2) comprises homogeneously mixing the phosphorus source with a part of water first, then adding the template agent and the rest of water, mixing them homogeneously, then adding the activated kaolin microspheres obtained in step 1), and mixing them homogeneously to obtain the gel.

4. The method according to claim 1, wherein the template agent is selected from one or more of triethylamine, diethylamine, and tetraethylammonium hydroxide.

5. The method according to claim 1, wherein the phosphorus source is phosphoric acid.

6. The method according to claim 1, wherein step 3) comprises mixing the gel obtained in step 2) and the ZSM-5 molecular sieve wherein the ZSM-5 has a Si/Al molar ratio from 50 to 200; carrying out aging at an aging temperature of 40 C. to 90 C. and crystallization at a crystallization temperature of 180 C. to 220 C.; and wherein the separation to obtain the composite material of SAPO-34/ZSM-5@kaolin comprises the steps of precipitation, centrifuging, washing, and drying.

7. The method according to claim 6, wherein the ZSM-5 molecular sieve has a Si/Al molar ratio from 50 to 150.

8. The method according to claim 6, wherein the aging is carried out at an aging temperature of 40 C. to 90 C. for 15 to 60 min.

9. The method according to claim 6, wherein the crystallization is carried out at a crystallization temperature of 180 C. to 220 C. for 24 to 72 h.

10. The method according to claim 1, wherein in step 3), the separation comprises the steps of precipitation, centrifuging, washing, and drying.

11. The method according to claim 1, wherein step 4) comprises subjecting the composite material obtained in step 3) to ammonium exchange treatment in an aqueous solution of ammonium chloride, drying, and baking, to obtain the composite catalytic material of SAPO-34/ZSM-5@kaolin microspheres.

12. The method according to claim 11, wherein in step 4), the aqueous solution of ammonium chloride has a molar concentration of 0.1 to 1 M.

13. The method according to claim 11, wherein in step 4), the ammonium exchange treatment comprises stirring the composite material obtained in step 3) in an aqueous solution of ammonium chloride for 2 to 6 h at 60 C. to 90 C.

14. The method according to claim 1, wherein in Step 4), the baking temperature is 500 C. to 600 C., and the baking duration is 3 to 6 h.

15. The method according to claim 1, wherein step 1) comprises processing kaolin into kaolin microspheres by mixing kaolin with water and a binder and then spray-drying the mixture to prepare kaolin microspheres, the mass ratio of the kaolin to the binder is from 1.5 to 2.75.

16. The method according to claim 15, wherein the binder is selected from one or more of water glass, alumina sol, and silica sol.

17. The method according to claim 15, wherein step 1) comprises baking the kaolin microspheres to obtain activated kaolin microspheres at a baking temperature of 650 C. to 900 C. for a baking duration of 1 to 6 h.

18. A composite catalytic material of SAPO-34/ZSM-5 @kaolin microspheres prepared by the method according to claim 1, wherein, based on the relative crystallinity, the relative content of the SAPO-34 molecular sieve is 7 to 15 wt %, and the relative content of the ZSM-5 molecular sieve is 6 to 12 wt %.

19. A method for producing olefins from methanol, comprising: providing an aqueous solution of methanol as a raw material; contacting the composite catalytic material of SAPO-34/ZSM-5@kaolin microspheres according to claim 9 as a catalyst to prepare olefins from the raw material.

20. The method according to claim 19, wherein, the olefins are prepared at the conditions of normal pressure, a reaction temperature of 400 C. to 500 C., and a weight hourly space velocity (WHSV) of 2 to 3 h.sup.1.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is an X-ray diffraction (XRD) pattern of the composite material obtained in Example 1.

(2) FIG. 2A is a 1000 magnification of a field emission scanning electron microscopy (FESEM) image of the composite material obtained in Example 1.

(3) FIG. 2B is a 10000 magnification of a FESEM image of the composite material obtained in Example 1.

(4) FIG. 3 is an XRD pattern of the composite material obtained in Example 2.

(5) FIG. 4 is an XRD pattern of the composite material obtained in Example 3.

(6) FIG. 5 is an XRD pattern of the composite material obtained in Example 4.

(7) FIG. 6 is an XRD pattern of the composite material obtained in Example 5.

(8) FIG. 7 is an XRD pattern of the composite material obtained in Example 6.

(9) FIG. 8 is an XRD pattern of the composite material obtained in Example 7.

(10) FIG. 9 is an XRD pattern of the composite material obtained in Comparative Example 1.

(11) FIG. 10A is a 2000 magnification of an FESEM image of the composite material obtained in Comparative Example 1.

(12) FIG. 10B is a 20000 magnification of a FESEM image of the composite material obtained in Comparative Example 1.

(13) FIG. 11 is an XRD pattern of the composite material obtained in Comparative Example 2.

(14) FIG. 12A is a 500 magnification of an FESEM image of the composite material obtained in Comparative Example 2.

(15) FIG. 12B is a 10000 magnification of a FESEM image of the composite material obtained in Comparative Example 2.

DETAILED DESCRIPTION OF INVENTION

(16) The implementation and beneficial effects of the present invention are described in detail below in combination with Examples to help readers better understand the spirit and features of the present invention, but the following description is not to limit the implementable scope of the present invention.

(17) According to the present invention, the crystal phase structure of samples is determined by X-ray diffraction (XRD), and the morphology and form of crystal of samples were determined by field emission scanning electron microscopy (FESEM).

(18) According to the present invention, the contents of SAPO-34 and ZSM-5 molecular sieves in the composite material are derived from the relative crystallinity. Relative crystallinity refers to the ratio of the area of characteristic peaks of each molecular sieve in an in situ crystallized product to that of a corresponding standard sample of the molecular sieve. The characteristic peaks of the SAPO-34 molecular sieve are peaks at 2 of 9.5, 16.0, 20.5, and 31, and the characteristic peaks of the ZSM-5 molecular sieve are peaks at 2 of 22.5 to 25. The standard samples of the molecular sieves are the normal micro-porous SAPO-34 molecular sieve produced by Nankai University Catalyst Co. Ltd., and a self-made micro-porous ZSM-5 molecular sieve, the crystallinity of which are set as 100%.

Example 1

(19) 100 g kaolin, 350 g water, and 40 g alumina sol were homogeneously mixed and spray-dried to obtain kaolin microspheres, which were baked at 700 C. for 4 h and ready for use.

(20) 4 g phosphoric acid was weighed out and mixed with 10 g water. The mixture was stirred for 30 min, and 4 g triethylamine and 10 g water were added thereto under stirring, following by further stirring. 5 g kaolin microspheres were added, and the mixture was allowed to stand for 2 h. The resultant gel comprised the following components in a molar ratio of 4R:0.30SiO.sub.2:1.85Al.sub.2O.sub.3:2P.sub.2O.sub.5:111H.sub.2O.

(21) 1.5 g dry powder of a ZSM-5 molecular sieve having a SiO.sub.2/Al.sub.2O.sub.3 of 200, which had not been subjected to template removal, was weighed out and added to the above liquid mixture such that the mass ratio of ZSM-5 dry powder to gel was 0.045, followed by stirring at 40 C. for 30 min.

(22) The resultant liquid mixture was transferred to a sealed high-pressure crystallizing kettle, and crystallization was carried out in a rotary oven at 180 C. for 24 h.

(23) The product was taken out and allowed to stand and precipitate for 5 min. The non-in situ products in the upper layer of liquid were removed, and the precipitated in situ product was separated by centrifuging, washed, dried at 100 C. for 4 h, subjected to ammonium exchange treatment twice in 0.5 M ammonium chloride (in each exchange, the in situ product was put in an aqueous solution of ammonium chloride and stirred at 80 C. for 4 h), and baked at 520 C. for 3 h, to obtain a composite catalytic material of SAPO-34/ZSM-5@kaolin microspheres. After quantification by XRD, the content of SAPO-34 molecular sieve in the product was 7% by weight, and the content of ZSM-5 molecular sieve in the product was 9% by weight. The XRD pattern of the composite material is shown in FIG. 1, and the SEM images thereof are shown in FIG. 2.

Example 2

(24) 100 g kaolin, 350 g water, and 35 g alumina sol were homogeneously mixed and spray-dried to obtain kaolin microspheres, which were baked at 800 C. for 4 h and ready for use.

(25) 5 g phosphoric acid was weighed out and mixed with 15 g water. The mixture was stirred for 30 min, and 5 g triethylamine and 15 g water were added thereto under stirring, following by further stirring. 5 g kaolin microspheres were added, and the mixture was allowed to stand for 2 h. The resultant gel comprised the following components in a molar ratio of 5R:0.20SiO.sub.2:1.47Al.sub.2O.sub.3:2.6P.sub.2O.sub.5:166H.sub.2O.

(26) 2 g dry powder of a ZSM-5 molecular sieve having a SiO.sub.2/Al.sub.2O.sub.3 of 80, which had not been subjected to template removal, was weighed out and added to the above liquid mixture such that the mass ratio of ZSM-5 dry powder to gel was 0.044, followed by stirring at 70 C. for 30 min.

(27) The resultant liquid mixture was transferred to a sealed high-pressure crystallizing kettle, and crystallization was carried out in a rotary oven at 200 C. for 48 h.

(28) The product was taken out and allowed to stand and precipitate for 5 min. The non-in situ products in the upper layer of liquid were removed, and the precipitated in situ product was separated by centrifuging, washed, dried at 120 C. for 6 h, subjected to ammonium exchange treatment twice in 1.0 M ammonium chloride (in each exchange, the in situ product was put in an aqueous solution of ammonium chloride and stirred at 75 C. for 4 h), and baked at 550 C. for 4 h, to obtain a composite catalyst of SAPO-34/ZSM-5@kaolin microspheres. After quantification by XRD, the content of SAPO-34 molecular sieve in the product was 15% by weight, and the content of ZSM-5 molecular sieve in the product was 12% by weight. The XRD pattern of the composite material is shown in FIG. 3.

Example 3

(29) 100 g kaolin, 350 g water, 52 g alumina sol, and 15 g silica sol were homogeneously mixed and spray-dried to obtain kaolin microspheres, which were baked at 900 C. for 6 h and ready for use.

(30) 6 g phosphoric acid was weighed out and mixed with 20 g water. The mixture was stirred for 30 min, and 6 g triethylamine and 20 g water were added thereto under stirring, following by further stirring. 5 g kaolin microspheres were added, and the mixture was allowed to stand for 2 h. The resultant gel comprised the following components in a molar ratio of 6R:0.27SiO.sub.2:0.58Al.sub.2O.sub.3:3.0P.sub.2O.sub.5:222H.sub.2O.

(31) 3.0 g dry powder of a ZSM-5 molecular sieve having a SiO.sub.2/Al.sub.2O.sub.3 of 100, which had been subjected to template removal, was weighed out and added to the above liquid mixture such that the mass ratio of ZSM-5 dry powder to gel was 0.053, followed by stirring at 90 C. for 60 min.

(32) The resultant liquid mixture was transferred to a sealed high-pressure crystallizing kettle, and crystallization was carried out in a rotary oven at 220 C. for 72 h.

(33) The product was taken out and allowed to stand and precipitate for 5 min. The non-in situ products in the upper layer of liquid were removed, and the precipitated in situ product was separated by centrifuging, washed, dried at 110 C. for 12 h, subjected to ammonium exchange treatment twice in 0.1 M ammonium chloride (in each exchange, the in situ product was put in an aqueous solution of ammonium chloride and stirred at 60 C. for 6 h), and baked at 600 C. for 6 h, to obtain a composite molecular sieve of SAPO-34/ZSM-5@kaolin microspheres. After quantification by XRD, the content of SAPO-34 molecular sieve in the product was 10% by weight, and the content of ZSM-5 molecular sieve in the product was 7.5% by weight. The XRD pattern of the composite material is shown in FIG. 4.

Example 4

(34) 100 g kaolin, 350 g water, and 45 g alumina sol were homogeneously mixed and spray-dried to obtain kaolin microspheres, which were baked at 800 C. for 4 h and ready for use.

(35) 5 g phosphoric acid was weighed out and mixed with 15 g water. The mixture was stirred for 30 min, and 5 g triethylamine and 15 g water were added thereto under stirring, following by further stirring. 5 g kaolin microspheres were added, and the mixture was allowed to stand for 2 h. The resultant gel comprised the following components in a molar ratio of 5R:0.20SiO.sub.2:1.47Al.sub.2O.sub.3:2.6P.sub.2O.sub.5:166H.sub.2O.

(36) 2 g dry powder of a ZSM-5 molecular sieve having a SiO.sub.2/Al.sub.2O.sub.3 of 50, which had not been subjected to template removal, was weighed out and added to the above liquid mixture such that the mass ratio of ZSM-5 dry powder to gel was 0.044, followed by stirring at 70 C. for 30 min.

(37) The resultant liquid mixture was transferred to a sealed high-pressure crystallizing kettle, and crystallization was carried out in a rotary oven at 200 C. for 48 h.

(38) The product was taken out and allowed to stand and precipitate for 5 min. The non-in situ products in the upper layer of liquid were removed, and the precipitated in situ product was separated by centrifuging, washed, dried at 105 C. for 8 h, subjected to ammonium exchange treatment twice in 0.6 M ammonium chloride (in each exchange, the in situ product was put in an aqueous solution of ammonium chloride and stirred at 65 C. for 5 h), and baked at 550 C. for 4 h, to obtain a composite molecular sieve of SAPO-34/ZSM-5@kaolin microspheres. After quantification by XRD, the content of SAPO-34 molecular sieve in the product was 11% by weight, and the content of ZSM-5 molecular sieve in the product was 6% by weight. The XRD pattern of the composite material is shown in FIG. 5.

Example 5

(39) 100 g kaolin, 350 g water, and 40 g alumina sol were homogeneously mixed and spray-dried to obtain kaolin microspheres, which were baked at 800 C. for 4 h and ready for use.

(40) 5 g phosphoric acid was weighed out and mixed with 15 g water. The mixture was stirred for 30 min, and 7.35 g tetraethylammonium hydroxide and 15 g water were added thereto under stirring, following by further stirring. 5 g kaolin microspheres were added, and the mixture was allowed to stand for 2 h. The resultant gel comprised the following components in a molar ratio of 5R:0.20SiO.sub.2:1.47Al.sub.2O.sub.3:2.6P.sub.2O.sub.5:166H.sub.2O.

(41) 2 g dry powder of a ZSM-5 molecular sieve having a SiO.sub.2/Al.sub.2O.sub.3 of 50, which had been subjected to template removal, was weighed out and added to the above liquid mixture such that the mass ratio of ZSM-5 dry powder to gel was 0.042, followed by stirring at 70 C. for 30 min.

(42) The resultant liquid mixture was transferred to a sealed high-pressure crystallizing kettle, and crystallization was carried out in a rotary oven at 200 C. for 48 h.

(43) The product was taken out and allowed to stand and precipitate for 5 min. The non-in situ products in the upper layer of liquid were removed, and the precipitated in situ product was separated by centrifuging, washed, dried at 120 C. for 6 h, subjected to ammonium exchange treatment twice in 0.5 M ammonium chloride (in each exchange, the in situ product was put in an aqueous solution of ammonium chloride and stirred at 85 C. for 2 h), and baked at 550 C. for 4 h, to obtain a composite molecular sieve of SAPO-34/ZSM-5@kaolin microspheres. This product has an XRD pattern similar to that of the product prepared in Example 2. The content of SAPO-34 molecular sieve in the product was 10% by weight, and the content of ZSM-5 molecular sieve in the product was 7% by weight. The XRD pattern of the composite material is shown in FIG. 6.

Example 6

(44) 100 g kaolin, 350 g water, and 40 g alumina sol were homogeneously mixed and spray-dried to obtain kaolin microspheres, which were baked at 800 C. for 4 h and ready for use.

(45) 5 g phosphoric acid was weighed out and mixed with 15 g water. The mixture was stirred for 30 min, and 3.65 g diethylamine and 15 g water were added thereto under stirring, following by further stirring. 5 g kaolin microspheres were added, and the mixture was allowed to stand for 2 h. The resultant gel comprised the following components in a molar ratio of 5R:0.20SiO.sub.2:1.47Al.sub.2O.sub.3:2.6P.sub.2O.sub.5:166H.sub.2O.

(46) 2 g dry powder of a ZSM-5 molecular sieve having a SiO.sub.2/Al.sub.2O.sub.3 of 50, which had not been subjected to template removal, was weighed out and added to the above liquid mixture such that the mass ratio of ZSM-5 dry powder to gel was 0.046, followed by stirring at 70 C. for 30 min.

(47) The resultant liquid mixture was transferred to a sealed high-pressure crystallizing kettle, and dynamic crystallization was carried out at 200 C. for 48 h.

(48) The product was taken out and allowed to stand and precipitate for 5 min. The non-in situ products in the upper layer of liquid were removed, and the precipitated in situ product was separated by centrifuging, washed, dried at 120 C. for 6 h, subjected to ammonium exchange treatment twice in 0.5 M ammonium chloride (in each exchange, the in situ product was put in an aqueous solution of ammonium chloride and stirred at 90 C. for 3 h), and baked at 550 C. for 4 h, to obtain a composite molecular sieve of SAPO-34/ZSM-5@kaolin microspheres. This product has an XRD pattern similar to that of the product prepared in Example 2. The content of SAPO-34 molecular sieve in the product was 11% by weight, and the content of ZSM-5 molecular sieve in the product was 6.5% by weight. The XRD pattern of the composite material is shown in FIG. 7.

Example 7

(49) 100 g kaolin, 350 g water, and 36 g silica sol were homogeneously mixed and spray-dried to obtain kaolin microspheres, which were baked at 800 C. for 4 h and ready for use.

(50) 5 g phosphoric acid was weighed out and mixed with 15 g water. The mixture was stirred for 30 min, and 1.33 g diethylamine, 3.67 g tetraethylammonium hydroxide and 15 g water were added thereto under stirring, following by further stirring. 5 g kaolin microspheres were added, and the mixture was allowed to stand for 2 h. The resultant gel comprised the following components in a molar ratio of 5R:0.20SiO.sub.2:1.47Al.sub.2O.sub.3:2.6P.sub.2O.sub.5:166H.sub.2O.

(51) 2 g dry powder of a ZSM-5 molecular sieve having a SiO.sub.2/Al.sub.2O.sub.3 of 60, which had not been subjected to template removal, was weighed out and added to the above liquid mixture such that the mass ratio of ZSM-5 dry powder to gel was 0.044, followed by stirring at 70 C. for 30 min.

(52) The resultant liquid mixture was transferred to a sealed high-pressure crystallizing kettle, and dynamic crystallization was carried out at 200 C. for 48 h.

(53) The product was taken out and allowed to stand and precipitate for 5 min. The non-in situ products in the upper layer of liquid were removed, and the precipitated in situ product was separated by centrifuging, washed, dried at 120 C. for 6 h, subjected to ammonium exchange treatment twice in 0.5 M ammonium chloride (in each exchange, the in situ product was put in an aqueous solution of ammonium chloride and stirred at 80 C. for 3 h), and baked at 550 C. for 4 h, to obtain a composite molecular sieve of SAPO-34/ZSM-5@kaolin microspheres. This product has an XRD pattern similar to that of the product prepared in Example 2. The content of SAPO-34 molecular sieve in the product was 12% by weight, and the content of ZSM-5 molecular sieve in the product was 6.8% by weight. The XRD pattern of the composite material is shown in FIG. 8.

Comparative Example 1

(54) 100 g kaolin, 350 g water, and 40 g alumina sol were homogeneously mixed and spray-dried to obtain kaolin microspheres, which were baked at 800 C. for 4 h and ready for use.

(55) 5 g phosphoric acid was weighed out and mixed with 15 g water. The mixture was stirred for 30 min, and 15 g water and 5 g triethylamine were added thereto under stirring, following by further stirring. 5 g kaolin microspheres were added, and the mixture was allowed to stand for 2 h. The resultant gel comprised the following components in a molar ratio of 5R:0.20SiO.sub.2:1.47Al.sub.2O.sub.3:2.6P.sub.2O.sub.5:166H.sub.2O.

(56) The liquid mixture obtained in step (1) was transferred to a sealed high-pressure crystallizing kettle, and crystallization was carried out in a rotary oven at 200 C. for 48 h.

(57) The product was taken out and allowed to stand and precipitate for 5 min. The non-in situ products in the upper layer of liquid were removed, and the precipitated in situ product was separated by centrifuging, washed, dried at 120 C. for 12 h, and baked at 550 C. for 4 h, to obtain a composite molecular sieve of SAPO-34@kaolin. After quantification by XRD, the content of SAPO-34 molecular sieve in the product was 30% by weight. The XRD pattern of the composite material is shown in FIG. 9, and the SEM images thereof are shown in FIG. 10.

Comparative Example 2

(58) 100 g kaolin, 350 g water, and 40 g alumina sol were homogeneously mixed and spray-dried to obtain kaolin microspheres, which were baked at 800 C. for 4 h and ready for use.

(59) 1.74 tetrapropylammonium bromide was weighed out and mixed with 70 g water. The mixture was stirred for 30 min. 5 g kaolin microspheres and 15 g water glass were added, and the mixture was stirred homogeneously.

(60) The liquid mixture obtained above was transferred to a sealed high-pressure crystallizing kettle, and crystallization was carried out in a rotary oven at 170 C. for 48 h.

(61) The product was taken out and allowed to stand and precipitate for 5 min. The non-in situ products in the upper layer of liquid were removed, and the precipitated in situ product was separated by centrifuging, washed, dried at 120 C. for 12 h, subjected to ammonium exchange treatment twice in 0.5 M ammonium chloride, and baked to obtain a composite molecular sieve of ZSM-5@kaolin. After quantification by XRD, the content of ZSM-5 molecular sieve in the product was 15% by weight. The XRD pattern of the composite material is shown in FIG. 11, and the SEM images thereof are shown in FIG. 12.

Comparative Example 3

(62) The composite molecular sieve of SAPO-34@kaolin microspheres synthesized by the method of Comparative example 1 and the composite molecular sieve of ZSM-5@kaolin microspheres synthesized by the method of Comparative example 2 were physically mixed in a mass ratio of 1:1. The homogeneously mixed mixture was evaluated for catalytic activity.

Experimental Example 1: Catalytic Performance of the Composite Catalysts of SAPO-34/ZSM-5@Kaolin Microspheres

(63) With a small-scale fixed-bed catalytic reaction evaluating device, the catalytic performance of the composite catalytic materials of SAPO-34/ZSM-5@kaolin prepared in Examples 1-7, the SAPO-34@kaolin prepared in Comparative example 1, the ZSM-5@kaolin prepared in Comparative example 2, and the composite of SAPO-34@kaolin and ZSM-5@kaolin prepared in Comparative example 3 as a catalyst in an MTO reaction was evaluated.

(64) For the evaluation, an aqueous solution of 95 wt % methanol was used as the starting material, and the conditions for evaluation were at a reaction temperature of 450 C., a weight hourly space velocity (WHSV) of 2.5 h.sup.1, and a carrier gas flow rate of 20 ml/min. The products after reaction were analyzed by off-line gas chromatography with a 3420A Gas Chromatographer (Beifen) using a HP PLOT-Q column and an FID detector for detection. When the methanol conversion was below 98 wt %, the catalyst was considered inactive, the experiment was stopped, and this time point was recorded as the catalyst life. The result of product selectivity was the maximum value among the samples taken during the methanol-to-olefin reaction. The results are shown in Table 1.

(65) TABLE-US-00001 TABLE 1 Results of evaluation of catalytic performance in methanol-to-olefin (MTO) reaction Samples Example 1 Example 2 Example 3 Example 4 Example 5 Methanol conversion 100 100 100 100 100 (wt. %) Catalyst life (min) 751 782 748 745 790 Ethylene yield (wt. %) 22 35 30 36 37 Propylene yield (wt. %) 46 40 42 37 40 Yield of ethylene + 68 75 72 73 77 propylene (wt. %) Yield of ethylene + 83 89 84 85 86 propylene + butylene (wt. %) Samples Example 6 Example 7 Comp. Ex. 1 Comp. Ex. 2 Comp. Ex. 3 Methanol conversion 100 100 100 100 100 (wt. %) Catalyst life (min) 775 740 51 1293 810 Ethylene yield (wt. %) 38 37 38 15 12 Propylene yield (wt. %) 40 42 40 38 43 Yield of ethylene + 78 79 78 53 55 propylene (wt. %) Yield of ethylene + 89 89 91 71 73 propylene + butylene (wt. %)

(66) The above experimental results demonstrate that by the method according to the present invention, the relative contents of SAPO-34 and ZSM-5 in the produced composite catalyst of SAPO-34/ZSM-5@kaolin microspheres can be changed by adjustment of the synthesis condition, and in turn the selectivity for ethylene and propylene in the MTO product can be adjusted. Meanwhile, as compared to the catalyst of SAPO-34@kaolin microspheres, the products synthesized in the examples have better activity and stability, and a catalyst life extended by 700 min or more; as compared to the catalyst of ZSM@kaolin and the mechanical catalyst of ZSM@kaolin+SAPO-35@kaolin, the products obtained according to the present invention result in better selectivity for ethylene, propylene, the duo (ethylene+propylene), and the trio (ethylene+propylene+butylene).