A CATALYST FOR PRODUCING LIGHT OLEFINS FROM CATALYTIC CRACKING OF HYDROCARBON HAVING 4 TO 7 CARBON ATOMS AND A PROCESS FOR PRODUCING LIGHT OLEFINS BY USING A CATALYST THEREOF

Abstract

The present invention relates to a catalyst for producing light olefins from catalytic cracking of hydrocarbon having 4 to 7 carbon atoms, wherein said catalyst comprises zeolite having the ring arrangement of 8 to 10 silicon atoms and hierarchical zeolite comprising 0.1 to 2 nm of micropore, 2 to 50 nm of mesopore, and greater than 50 nm of macropore, wherein the mesopore and macropore are greater than or equal to 40% when comparing to total pore volume, and said catalyst comprises element having 2.sup.+ to 4.sup.+ oxidation state with 0.1 to 3% by weight of the catalyst.

Claims

1. A catalyst for producing light olefins from catalytic cracking of hydrocarbon having 4 to 7 carbon atoms, wherein said catalyst comprises zeolite having 8 to 10 silicon atoms arranged in ring and hierarchical zeolite comprising 0.1 to 2 nm micropore, 2 to 50 nm mesopore, and more than 50 nm macropore, wherein the mesopore and macropore are 40% to 60% of the total pore volume, and said catalyst comprising element having 2.sup.+ to 4.sup.+ oxidation state of 0.1 to 3% by weight of the catalyst.

2. The catalyst according to claim 1, wherein said zeolite has a pore size of 0.35 nm to 0.54 nm.

3. The catalyst according to claim 1, wherein the hierarchical zeolite comprises 0.35 to 0.54 nm micropore and 2 to 10 nm mesopore.

4. (canceled)

5. The catalyst according to claim 1, wherein said zeolite is ferrierite.

6. The catalyst according to claim 1, wherein said zeolite has mole ratio of silica to alumina of 20 to 60.

7. The catalyst according to claim 1, wherein said element is selected from germanium, zirconium, or boron.

8. The catalyst according to claim 7, wherein said element is germanium.

9. The catalyst according to claim 1, wherein said element is 0.2 to 1% by weight of the catalyst.

10. The process for producing light olefins, comprising contacting hydrocarbon having 4 to 7 carbon atoms to the catalyst at a temperature of 550 to 650° C. and a pressure of 1 to 3 bars, wherein said catalyst comprising zeolite having 8 to 10 silicon atoms arranged in ring and hierarchical zeolite comprising 0.1 to 2 nm micropore, 2 to 50 nm mesopore, and more than 50 nm macropore, wherein the mesopore and macropore are 40% to 60% of the total pore volume, and said catalyst comprising element having 2.sup.+ to 4.sup.+ oxidation state of 0.1 to 3% by weight of the catalyst.

11. The process according to claim 10, wherein said zeolite has a pore size of 0.35 nm to 0.54 nm.

12. The process according to claim 10, wherein the hierarchical zeolite comprises 0.35 to 0.54 nm micropore and 2 to 10 nm mesopore.

13. (canceled)

14. The process according to claim 10, wherein said zeolite is ferrierite.

15. The process according to claim 10, wherein said zeolite has mole ratio of silica to alumina of 20 to 60.

16. The process according to claim 10, wherein said element is selected from germanium, zirconium, or boron.

17. The process according to claim 16, wherein said element is germanium.

18. The process according to claim 10, wherein said element is 0.2 to 1% by weight of the catalyst.

19. The process according to claim 10, wherein the hydrocarbon having 4 to 7 carbon atoms can be selected from butane, pentane, hexane and heptane.

20. The process according to claim 10, wherein the light olefin is ethylene, propylene, or a mixture thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 shows the specific characteristic of the crystal of the sample according to the invention and the comparative sample.

[0015] FIGS. 2A), B), C), and D) show results from the scanning electron microscope of the comparative sample A, the sample according to the invention 1, 2, and 3, respectively.

[0016] FIG. 3 shows the acidity of the sample according to the invention and the comparative sample.

[0017] FIG. 4 shows the conversion percentage of reactant to product of the sample according to the invention and the comparative sample for the catalytic cracking of pentane.

[0018] FIG. 5 shows the product selectivity of the sample according to the invention and the comparative sample for the catalytic cracking of pentane at the conversion percentage of reactant to product about 50%.

DESCRIPTION OF THE INVENTION

[0019] The present invention relates to the catalyst for producing light olefins from catalytic cracking of hydrocarbon having 4 to 7 carbon atoms and a process for producing light olefins by using a catalyst thereof, which will be described in the following aspects of the invention.

[0020] Any aspect being described herein also means to include the application to other aspects of this invention unless stated otherwise.

[0021] Technical terms or scientific terms used herein have definitions as understood by an ordinary person skilled in the art unless stated otherwise.

[0022] Any tools, equipment, methods, or chemicals named herein mean tools, equipment, methods, or chemicals being operated or used commonly by those person skilled in the art unless stated otherwise that they are tools, equipment, methods, or chemicals specific only in this invention.

[0023] Use of singular noun or singular pronoun with “comprising” in claims or specification means “one” and also including “one or more”, “at least one”, and “one or more than one”.

[0024] All compositions and/or methods disclosed and claims in this application are intended to cover embodiments from any operation, performance, modification, or adjustment any factors without any experiment that significantly different from this invention, and obtain with object with utility and resulted as same as the present embodiment according to person ordinary skilled in the art although without specifically stated in claims. Therefore, substitutable or similar object to the present embodiment, including any minor modification or adjustment that can be apparent to person skilled in the art should be construed as remains in spirit, scope, and concept of invention as appeared in appended claims.

[0025] Throughout this application, term “about” means any number that appeared or expressed herein that could be varied or deviated from any error of equipment, method, or personal using said equipment or method.

[0026] Hereafter, invention embodiments are shown without any purpose to limit any scope of the invention.

[0027] The present invention relates to the catalyst for producing light olefins from catalytic cracking of hydrocarbon having 4 to 7 carbon atoms, wherein said catalyst comprises zeolite having the ring arrangement of 8 to 10 silicon atoms and hierarchical zeolite comprising 0.1 to 2 nm of micropore, 2 to 50 nm of mesopore, and greater than 50 nm of macropore, wherein the mesopore and macropore are greater than or equal to 40% when comparing to total pore volume, and said catalyst comprises element having 2.sup.+ to 4.sup.+ oxidation state with 0.1 to 3% by weight of the catalyst.

[0028] In one aspect of the invention, the zeolite according to the invention has pore size of 0.35 nm to 0.54 nm.

[0029] Preferably, said hierarchical zeolite comprises micropore having size in the range of 0.35 to 0.54 nm and mesopore having size in the range of 2 to 10 nm, wherein the mesopore is greater than or equal to 40% when comparing to total pore volume. Most preferably, the mesopore is 40 to 60% when comparing to total pore volume.

[0030] In one aspect of the invention, zeolite having the ring arrangement of 8 to 10 silicon atoms is ferrierite.

[0031] In one aspect of the invention, zeolite has the mole ratio of silica to alumina from 20 to 60.

[0032] In one aspect of the invention, element having 2.sup.+ to 4.sup.+ oxidation state is selected from germanium, zirconium, or boron, preferably germanium.

[0033] In one aspect of the invention, said element is in the amount of 0.1 to 3% by weight of the catalyst, preferably in the amount of 0.2 to 1% by weight of the catalyst.

[0034] In one aspect of the invention, the catalyst according to the invention may be prepared by the following steps:

[0035] (a) preparing the solution containing the alumina compound, silica compound, and the soft structure-directing agents;

[0036] (b) subjecting the mixture obtained from step (a) to the hydrothermal process at the determined temperature and time in order to make said mixture to form the hierarchical zeolite; and

[0037] (c) drying the hierarchical zeolite from step (b);

[0038] wherein the soft structure-directing agents in step (a) are pyrrolidine and 3-(trimethoxysilyl)-propyl-octadecyl-dimethyl-ammonium chloride (TPOAC);

[0039] wherein the soft structure-directing agent in step (a) is quaternary ammonium salt containing silane group.

[0040] In one aspect of the invention, in step (a), the compound for preparing zeolite is the mixture of alumina compound selected from aluminum isopropoxide, sodium aluminate, or aluminium sulfate, and silica compound selected from tetraethyl orthosilicate, sodium silicate, or silica gel.

[0041] In one aspect of the invention, step (a) may further comprise the precursor compound of element having 2.sup.+ to 4.sup.+ oxidation state that may be selected from germanium oxide, germanium chloride, zirconium oxychloride, zirconyl nitrate, or boric acid.

[0042] In one aspect of the invention, step (b) is operated at the temperature in the range of about 130 to 180° C. for 3 to 6 days.

[0043] In another aspect, said catalyst preparation process may further comprise the steps of drying and calcination.

[0044] Drying may be performed by conventional drying method using oven, vacuum drying, stirred evaporation, and drying by rotary evaporator.

[0045] Calcination may be performed under atmospheric condition for about 4 to 10 hours, and the temperature in the range of about 400 to 650° C., preferably about 4 to 6 hours and the temperature in the range of about 550 to 600° C.

[0046] In another aspect of the invention, the present invention relates to the process for producing light olefins, comprising contact of hydrocarbon compound having 4 to 7 carbon atoms to the catalyst at the temperature of about 550 to 650° C. and the pressure of about 1 to 3 bars, wherein the catalyst is selected from catalyst according to the invention as described above.

[0047] In one aspect of the invention, the hydrocarbon compound having 4 to 7 carbon atoms can be selected from butane, pentane, hexane and heptane.

[0048] In one aspect of the invention, the catalytic cracking may be operated in fixed bed system, moving bed system, fluidized bed system, or batch system.

[0049] The weight hourly space velocity (WHSV) of the feed line of the hydrocarbon compound in the catalytic cracking is in the range of about 1 to 6.5 per hour, preferably in the range of about 2 to 5 per hour.

[0050] Generally, any person skilled in this art can adjust the catalytic cracking condition to be suitable for type and composition of feed line, catalyst, and reactor system.

[0051] The following examples are only for demonstrating one aspect of this invention, not for limiting the scope of this invention in any way.

[0052] Preparation of the Catalyst

[0053] The preparation of the catalyst according to the invention can be done by the following methods.

[0054] Preparation of the Hierarchical Zeolite Containing Element Having 2.sup.+ to 4.sup.+ Oxidation State in its Structure

[0055] The solution containing aluminum sulfate and sodium silicate was prepared with the mole ratio of silica to alumina about 44 and using pyrrolidine and trimethoxysilyl-propyl-octadecyl-dimethyl-ammonium chloride as the structure-directing agents of the zeolite. The addition of element having 2.sup.+ to 4.sup.+ oxidation state by in-situ method could be done by adding precursor compound of the desired element with the ratio of desired element to zeolite of about 0.2-1% by weight into the mixture of alumina compound, silica compound, and structure-directing agents. Then, the obtained mixture was subjected to the hydrothermal process at the temperature about 130-180° C. for about 3-6 days in order to make said mixture to form the zeolite.

[0056] Then, the obtained zeolite was washed with deionized water until the pH of washed water was less than 9. The obtained substance was dried at the temperature about 100-200° C. for 12-24 hours. Then, the substance was calcined in order to remove the structure-directing agents at the temperature about 500-650° C. for about 8-12 hours. The hierarchical zeolite was obtained as white powder.

[0057] Then, the ion exchange was performed on the synthesized zeolite catalyst by dissolving the obtained zeolite in about 0.1 M of ammonium nitrate solution (NH.sub.4NO.sub.3) at the temperature about 80° C. The mixture was stirred for about 2 hours and washed with purified water, and then the zeolite was dried. Then, the zeolite was calcined at the temperature about 550° C. for about 6 hours.

[0058] Comparative Sample Cat A

[0059] The comparative sample Cat A is the conventional ferrierite zeolite prepared with the solution containing aluminum sulfate and sodium silicate. The mole ratio of silica to alumina was 44 and only pyrrolidine was used as the structure-directing agent of the zeolite. Then, the obtained mixture was subjected to the hydrothermal process at the temperature about 130-180° C. for about 3-6 days in order to make said mixture to form the zeolite. Then, the zeolite catalyst synthesized was washed and subjected to ion exchange by dissolving the obtained zeolite in about 0.1 M of ammonium nitrate solution (NH.sub.4NO.sub.3) at the temperature about 80° C. The mixture was stirred for about 2 hours and washed with purified water, and then the zeolite was dried. Then, the zeolite was calcined at the temperature about 550° C. for about 6 hours.

[0060] Sample According to the Invention Cat 1

[0061] The sample according to the invention Cat 1 was prepared by the method described for the preparation of the hierarchical zeolite using zirconyl nitrate as the precursor compound in order to contain zirconium in the catalyst composition with ratio of zirconium to zeolite about 0.2% by weight.

[0062] Sample According to the Invention Cat 2

[0063] The sample according to the invention Cat 2 was prepared by the method described for the preparation of the hierarchical zeolite using boric acid as the precursor compound in order to contain boron in the catalyst composition with ratio of boron to zeolite about 0.5% by weight.

[0064] Sample According to the Invention Cat 3

[0065] The sample according to the invention Cat 3 was prepared by the method described for the preparation of the hierarchical zeolite using germanium oxide as the precursor compound in order to contain germanium in the catalyst composition with ratio of germanium to zeolite about 0.2% by weight.

[0066] Sample According to the Invention Cat 4

[0067] The sample according to the invention Cat 4 was prepared by the method described for the preparation of the hierarchical zeolite using germanium oxide as the precursor compound in order to contain germanium in the catalyst composition with ratio of germanium to zeolite about 0.5% by weight.

[0068] Sample According to the Invention Cat 5

[0069] The sample according to the invention Cat 5 was prepared by the method described for the preparation of the hierarchical zeolite using germanium oxide as the precursor compound in order to contain germanium in the catalyst composition with ratio of germanium to zeolite about 1% by weight.

[0070] Testing of the Catalytic Cracking of the Hydrocarbon Having 4 to 7 Carbon Atoms for Producing Light Olefins as Product

[0071] The testing of catalytic cracking of the hydrocarbon having 4 to 7 carbon atoms for the production of light olefins may be performed under the following conditions.

[0072] The catalytic cracking was operated in the fixed bed reactor using about 0.5 g of the catalyst. Prior to the reaction, the catalyst was contacted with the mixed gases of hydrogen in helium having flow rate about 40 mL/min for about 3 hours. Then, the hydrocarbon having 5 carbon atoms was fed with the flow rate about 1 g/hour. The reaction was operated at the temperature about 600-625° C. under atmospheric pressure and the weight hourly space velocity (WHSV) was about 2 per hour.

[0073] Then, the reaction was monitored by measuring the change of reactant and the formation of product compositions after subjecting to the catalyst at any time with using gas chromatography technique equipped with the outlet of the fixed bed reactor, and using flame ionization detector (FID) as the detector and GASPRO capillary column for separating analysis of each composition of said compound.

[0074] FIG. 1 shows the specific characteristic of the crystal of the sample according to the invention and the comparative sample which shows the ferrierite zeolite structure.

[0075] Moreover, in order to show the crystal structure, the scanning electron microscope (SEM) was used to analyze as shown in FIG. 2 which shows that the comparative sample Cat A had no certain characteristic of the crystal, but the sample according to the invention had spherical crystal having crystal size in the range of 3-6 μm and being more porous than the comparative sample.

[0076] Table 1 shows the physical properties of the comparative sample and the sample according to the invention. According to the result, it was found that the zeolite prepared from the invention had hierarchical pores comprising micropore and mesopore, wherein the mesopore was greater than or equal to 40% when comparing to total pore volume and had amount more than the conventional zeolite. Moreover, in order to show the characteristic of crystal structure, the scanning electron microscope (SEM) was used to analyze. The results were showed in FIG. 2 which shows that the zeolite according to the invention had hierarchical pores comprising rough surface when compared to the conventional zeolite.

TABLE-US-00001 TABLE 1 Specific surface area and porous properties of the comparative sample and the sample according to the invention Specific External Total pore Mesopore surface area surface area volume volume Percentage (S.sub.BET) (S.sub.ext) (V.sub.total) (V.sub.meso) of mesopore Sample (m.sup.2/g) (m.sup.2/g) (cm.sup.3/g) (cm.sup.3/g) volume (%) Comparative sample 341 12 0.16 0.03 18 Cat A Sample according to 236 59 0.21 0.12 58 the invention CAT1 Sample according to 300 55 0.22 0.10 45 the invention CAT2 Sample according to 218 52 0.20 0.11 57 the invention CAT3 Note: S.sub.BET: specific surface area; S.sub.ext: external surface area; V.sub.total: total pore volume; V.sub.meso: mesopore volume

[0077] FIG. 3 shows the acidity of the catalyst according to the invention and the comparative sample. It was found that the sample according to the invention had less acidity than the comparative sample.

[0078] In order to study the effect of the catalyst, which was the hierarchical zeolite and had metal inside its structure, on the production efficacy of light olefins from catalytic cracking for the hydrocarbon having 4 to 7 carbon atoms, different catalysts according to the invention were subjected to study with the comparative sample. The results are shown in FIG. 4 and FIG. 5.

[0079] FIG. 4 shows the conversion percentage of reactant to product of the sample according to the invention and the comparative sample for the catalytic cracking of pentane. It was found that the sample according to the invention gave better efficacy than the comparative sample. Especially, it was found that the structure of the catalyst according to the invention significantly reduced the catalyst deactivation.

[0080] FIG. 5 shows the product selectivity of the sample according to the invention and the comparative sample for the catalytic cracking of pentane at the conversion percentage of reactant to product about 50%. It was found that the sample according to the invention gave higher selectivity to light olefins comparing to the comparative sample.

[0081] From the results above, it can be said that the catalyst, which was hierarchical zeolite and had element having 2.sup.+ to 4.sup.+ oxidation state within its structure, give high conversion percentage of reactant to product and high selectivity to light olefins for the catalytic cracking of the hydrocarbon having 4 to 7 carbon atoms as stated in the objective of this invention.

BEST MODE OR PREFERRED EMBODIMENT OF THE INVENTION

[0082] Best mode or preferred embodiment of the invention is as provided in the description of the invention.