MESOPOROUS COBALT-METAL OXIDE CATALYST FOR FISCHER-TROPSCH SYNTHESIS REACTIONS AND A PREPARING METHOD THEREOF

Abstract

The present invention relates to a mesoporous cobalt-metal oxide catalyst for the Fischer-Tropsch synthesis and a method of preparing the same. The mesoporous cobalt-metal oxide catalyst for the Fischer-Tropsch synthesis of the present invention can very stably maintain the mesoporous structure even under a H.sub.2-rich high-temperature reduction condition and under a reaction condition of the low-temperature Fischer-Tropsch synthesis, easily transport reactants to the active site of the catalyst due to structural stability, and facilitate the release of heavier hydrocarbon products after production thereof. Additionally, unlike the conventional cobalt-based catalysts which are prepared by adding various co-catalysts for the purpose of improving reducibility, activity, selectivity and increasing thermal stability, etc., the mesoporous cobalt-metal oxide catalyst for the Fischer-Tropsch synthesis can constantly maintain conversion and selectivity at high levels without further requiring co-catalysts and thus it can be very effectively used for the Fischer-Tropsch synthesis.

Claims

1. A mesoporous cobalt-based catalyst for the Fischer-Tropsch synthesis comprising a main framework of a mesoporous structure, wherein the main framework is made of cobalt oxide, zirconia and/or alumina which are uniformly mixed.

2. The mesoporous cobalt-based catalyst of claim 1, wherein the main framework has a highly-ordered mesoporous structure.

3. The mesoporous cobalt-based catalyst of claim 1, wherein the main framework of a mesoporous structure mainly comprises the components represented by Formula 1 below:
COM.sub.aO.sub.b[Formula 1] wherein M is Zr or Al; and a or b is a molar ratio, wherein a and b are in the range of 0.1a0.35 and 1b4, respectively.

4. The mesoporous cobalt-based catalyst of claim 1, wherein the catalyst is synthesized or selected to have a meso-scale pores enabling a selective formation or release of a desired reaction product of Fischer-Tropsch synthesis.

5. The mesoporous cobalt-based catalyst of claim 1, wherein the main framework of a mesoporous structure is formed using mesoporous silica selected from the group consisting of KIT-6, SBA-15, SBA-16, MCM-41, MCM-48, HMS, AMS-8, AMS-10, FDU-1, FDU-2, and FDU-12, as a template.

6. The mesoporous cobalt-based catalyst of claim 1, wherein the specific surface area the catalyst is in the range of 45 m.sup.2/g to 200 m.sup.2/g and the average diameter of pore is in the range of 4 nm to 8 nm.

7. The mesoporous cobalt-based catalyst of claim 1, wherein alumina is further impregnated in the pores as a structural promoter, in the main framework of a mesoporous structure in which cobalt oxide, zirconia and/or alumina are uniformly mixed.

8. The mesoporous cobalt-based catalyst of claim 7, wherein alumina as a structural promoter is added in an amount of 2 wt % to 12 wt % relative to the total weight of the catalyst.

9. The mesoporous cobalt-based catalyst of claim 7, wherein platinum is further impregnated in the pores, in the main framework of a mesoporous structure.

10. The mesoporous cobalt-based catalyst of claim 1, wherein the main framework is made of CoZr.sub.aO.sub.b, CoAl.sub.aO.sub.b, Al.sub.2O.sub.3CoZr.sub.aO.sub.b, Al.sub.2O.sub.3CoAl.sub.aO.sub.b, Al.sub.2O.sub.3PtCoZr.sub.aO.sub.b, or a mixture thereof (wherein a and b are in the range of 0.1a0.35 and 1b4, respectively).

11. A method for preparing a mesoporous cobalt-based catalyst for the Fischer-Tropsch synthesis according to claim 1, comprising: (1) preparing a mixed solution in which a cobalt precursor, a zirconium precursor, and/or an aluminum precursor are dissolved; (2) filling the inside of the pores of a mesoporous template with the mixed solution in step (1) followed by drying and calcination; and (3) removing the mesoporous template to form the main framework of a mesoporous structure in which cobalt oxide, zirconia, and/or alumina are uniformly mixed.

12. The method of claim 11, wherein the method further comprises step (4) of further supporting alumina as a structural promoter inside of the pores of the main framework of a mesoporous structure.

13. The method of claim 11, wherein the solvent for the mixed solution of step (1) is at least one selected from the group consisting of distilled water, methanol, ethanol, and ethylene glycol.

14. The method of claim 11, wherein the cobalt precursor is selected from the group consisting of cobalt chloride (CoCl.sub.2.6H.sub.2O), cobalt acetate ((CH.sub.3COO).sub.2Co.4H.sub.2O), and cobalt nitrate (Co(NO.sub.3).sub.2.6H.sub.2O); a zirconium precursor is selected from the group consisting of zirconium oxynitrate hydrate (ZrO(NO.sub.3).sub.2.H.sub.2O), zirconium chloride octahydrate (ZrOCl.sub.2.8H.sub.2O), and zirconium acetate hydroxide ((CH.sub.3CO.sub.2).sub.xZr(OH).sub.y); and an aluminum precursor is selected from the group consisting of aluminum nitrate nonahydrate (Al(NO.sub.3).sub.3.9H.sub.2O), aluminum chloride hexahydrate (AlCl.sub.3.6H.sub.2O), and aluminum acetate (Al(OH)(C.sub.2H.sub.3O.sub.2).sub.2.

15. The method of claim 11, wherein the cobalt precursor and the zirconium precursor and/or the aluminum precursor in step (1) are mixed in a weight ratio of 1:0.1 to 1:0.3.

16. The method of claim 12, wherein step (4) comprises impregnating, drying, and calcinating the main framework of a mesoporous structure formed in step (3) in a solution containing the aluminum precursor.

17. The method of claim 12, wherein the method further comprises step (5) of further supporting platinum precursor after step (4).

18. The method of claim 17, wherein the platinum precursor used in step (5) is selected from the group consisting of tetraammineplatinum nitrate, platinum dichloride, platinum acetylacetonate, diammine dinitro platinum, and sodium hexachloroplatinate hexahydrate.

19. A method of preparing middle distillate-based liquid hydrocarbons from syngas by the low-temperature Fischer-Tropsch synthesis, comprising: i) applying the mesoporous cobalt-based catalyst for the Fischer-Tropsch synthesis according to claim 1 to a fixed-bed reactor for the Fischer-Tropsch synthesis; ii) activating the catalyst by reducing under a high-temperature hydrogen atmosphere; and iii) carrying out the Fischer-Tropsch synthesis using the activated catalyst for the low-temperature Fischer-Tropsch synthesis.

20. The method of claim 19, wherein the low-temperature Fischer-Tropsch synthesis is carried out at a reaction temperature of 200 C. to 350 C. under a reaction pressure of 10 bar to 30 bar and at a space velocity of 8,000 L/kg.Math.cat./h to 64,000 L/kg.Math.cat./h.

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0078] FIG. 1 is a diagram showing the CO conversion data with TOS (Time On Stream) during the reaction time of 60 hours for the catalyst according to Example 3, Example 6, and Comparative Example 1. In the case in which the meso framework was substituted with an oxide, and Al.sub.2O.sub.3 was used as a structural promoter, it was confirmed that the significantly stable catalytic activity was constantly maintained during the reaction time of 60 hours.

[0079] FIG. 2 is a diagram showing XRD measurement results which confirm the crystal structure of the catalyst in Example 3, Example 6, and Comparative Example 1 according to one embodiment.

[0080] FIG. 3 is a diagram showing SEM measurement results of the catalyst in Example 3, Example 6, and Comparative Example 1 according to one embodiment.

[0081] FIG. 4 is a diagram comparing pore volume relative to pore diameter of the catalyst in Example 3, Example 6, and Comparative Example 1 according to one embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0082] The present invention will be described in detail with accompanying examples hereinbelow. However, the Examples disclosed herein are only for illustrative objects and should not be construed as limiting the scope of the present invention.

Preparation Example 1

Preparation of Mesoporous Silica (KIT-6)

[0083] In order to use KIT-6 as a hard template for the mesoporous cobalt-metal oxide hybrid catalyst (meso-CoZr.sub.0.25O.sub.x, meso-CoAl.sub.0.25O.sub.x), the KIT-6 was prepared as follows.

[0084] 16.0 g of pluronic p123 copolymer, as the organic structure directing agent which forms three-dimensional mesoporous silica structure by forming micelles in an aqueous solution, was mixed with 150 ml of distilled water and was stirred until completely dissolved in the distilled water. Then, 25 ml of a 37% hydrochloric aqueous solution was mixed with 428 ml of distilled water and stirred by adjusting the internal temperature to 35 C. After confirming that the pluronic p123 copolymer aqueous solution prepared above was completely dissolved in the distilled water, the solution was poured into the hydrochloric solution, being stirred and mixed therewith. The mixed solution was then stirred for about 10 minutes, and 16.0 g of n-butanol was added to the mixed solution while stirring. The resultant was further stirred for 1 hour while maintaining the reaction temperature at 35 C., and thereafter, 34.4 g of TEOS (tetraethoxysilane) was added at once to the reaction solution being stirred, and the resultant was mildly stirred for 24 hours at the reaction temperature of 35 C.

[0085] After the 24-hour stirring was completed, the production of white silica precipitation in the reaction solution was confirmed. The solution was then transferred to an autoclave equipped with Teflon containers, and hydrothermal synthesis was carried out using the pressure naturally generated for 24 hours at 100 C. without stirring. The reaction solution after the hydrothermal reaction was filtered without washing process before it was completely cooled, the remaining solvent was sufficiently removed by the filtration, and the resultant was dried for 1 hour in an oven at 110 C. A mixed solution of 30 ml of a 37% hydrochloric acid aqueous solution and 300 ml of ethanol was prepared, and the white powder was mixed with the hydrochloric acid solution after drying. The resultant was then stirred for about 2 hours to remove the pluronic p 123 copolymer used as a structure forming agent, that is, surfactant extraction was carried out. After stirring, the solution was washed with distilled water and dried in an oven at 110 C. for about 1 hour to 2 hours. The white powder after drying was calcined by raising the heating temperature to 550 C. at a heating speed of 1 C./min and maintaining the temperature for 6 hours, and finally KIT-6 mesoporous silica in the form of a fine white powder was prepared. It was confirmed that the specific surface area of the prepared KIT-6 was 631 m.sup.2/g and the average pore size thereof was 5.8 nm.

Example 1

Preparation of Mesoporous Cobalt Zirconia (Meso-CoZr.SUB.0.25.O.SUB.x.) Catalyst

[0086] 10.0 g of KIT-6 prepared in the preparation Example 1 was dried in an oven at 110 C. for about one hour to eliminate the remaining moisture. 9.5 g of cobalt nitrate hexahydrate (97.0%), which is a cobalt precursor, and 2.3 g of zirconium nitrate oxide dihydrate (99.0%), which is a zirconium precursor, were added to about 10.0 g of distilled water and completely dissolved. The solution containing the cobalt and zirconium precursors was added at once to the KIT-6 powder after drying and mixed for a sufficient amount of time to allow the solution of precursors to infiltrate into the inside of the pores. Scarlet-colored KIT-6 powder, in which the solution of precursors is well mixed, was dried at 80 C., which is lower than the boiling point of distilled water, the solvent, for 12 hours, and underwent slow evaporation of water, which is the solvent. After drying, the powder was calcined by raising the heating temperature to 550 C. at a heating speed of 1 C./min and maintaining the temperature for 3 hours.

[0087] After calcination, a 2 M NaOH aqueous solution was prepared for the treatment of a strong base as a step of removing KIT-6 (template extraction). About 32.8 g of NaOH powder was added to 400 ml of distilled water and was completely dissolved to prepare a strong base aqueous solution, and the cobalt-zirconia powder mixed with sintered KIT-6 was added to 200 ml of the prepared 2 M NaOH aqueous solution and slowly stirred for about 30 minutes. After stirring for 30 minutes, the catalyst solution was centrifuged for 10 minutes at 9000 rpm to separate and release the base solution from the catalyst, and the catalyst was washed with 200 ml of the 2 M NaOH aqueous solution for the second time and underwent additional washing for a total of four times each with distilled water and acetone twice. Since the powder of the prepared mesoporous cobalt-zirconia (meso-CoZr.sub.0.25O.sub.x) catalyst is very fine, the washing process was repetitively carried out using a centrifugation instead of using a filter. After washing, the catalyst was dried at room temperature for 2 days and collected to finally prepare the mesoporous cobalt-zirconia catalyst.

Example 2

Preparation of Al.SUB.2.O.SUB.3.(5)/Meso-CoZr.SUB.0.125.O.SUB.x .Catalyst

[0088] (1) Step 1: Preparation of Mesoporous Cobalt-Zirconia Catalyst (Meso-CoZr.sub.0.125O.sub.x)

[0089] The mesoporous cobalt-zirconia catalyst (meso-CoZr.sub.0.125O.sub.x) was obtained in the same way as described in Example 1 except that 1.1 g of zirconium nitrate oxide dihydrate was used instead of 2.3 g.

[0090] (2) Step 2: Preparation of Al.sub.2O.sub.3(5)/Meso-CoZr.sub.0.125O.sub.x Catalyst

[0091] 5.0% of alumina (Al.sub.2O.sub.3) relative to the weight of the mesoporous cobalt-zirconia catalyst (meso-CoZr.sub.0.125O.sub.x) as a promoter ingredient was impregnated in the mesoporous cobalt-zirconia catalyst (meso-CoZr.sub.0.125O.sub.x) prepared in step 1 above.

[0092] 1.2 g of aluminum nitrate nonahydrate (98.0%), which is an aluminum precursor, was dissolved in about 2 g of distilled water. 3 g of the prepared mesoporous cobalt-zirconia catalyst (meso-CoZr.sub.0.125O.sub.x) was initially dried for about 1 hour in an oven at 110 C. to eliminate moisture. A solution containing the aluminum precursor was added to the mesoporous cobalt-zirconia catalyst (meso-CoZr.sub.0.125O.sub.x) after drying to prepare a mesoporous cobalt-zirconia catalyst in which the alumina is added by 5% relative to the weight of the catalyst by wet impregnation. The catalyst powder mixed with the aluminum precursor was slowly dried for about 12 hours in an oven at 80 C. to evaporate distilled water, which is the solvent. The catalyst after drying was collected and calcined by raising the heating temperature to 550 C. at a heating speed of 1 C./min and maintaining the temperature for 3 hours. The catalyst prepared above was denoted as Al.sub.2O.sub.3(5)/meso-CoZr.sub.0.125O.sub.x, and it was confirmed that the specific surface area of the catalyst prepared was 73.4 m.sup.2/g and the average pore size was 3.9 nm.

Example 3

Preparation of Al.SUB.2.O.SUB.3.(5)/Meso-CoZr.SUB.0.25.O.SUB.x

[0093] Al.sub.2O.sub.3(5)/meso-CoZr.sub.0.25O.sub.x was obtained in the same way as described in Example 2 except that a mesoporous cobalt-zirconia catalyst (meso-CoZr.sub.0.25O.sub.x) was used.

[0094] It was confirmed that the specific surface area of the prepared catalyst was 74.9 m.sup.2/g and the average pore size was 5.9 nm.

Example 4

Preparation of Al.SUB.2.O.SUB.3.(5)-Pt(1)/Meso-CoZr.SUB.0.25.O.SUB.x

[0095] 3 g of the mesoporous cobalt-zirconia catalyst (Al.sub.2O.sub.3(5)/meso-CoZr.sub.0.25O.sub.x) obtained in Example 3 was initially dried for about 1 hour in an oven at 110 C. to eliminate moisture.

[0096] A solution containing a platinum precursor, in which 0.06 g of tetraammineplatinum nitrate (99.99%) was dissolved in about 2 g of distilled water, was added to the mesoporous cobalt-zirconia catalyst (Al.sub.2O.sub.3(5)/meso-CoZr.sub.0.25O.sub.x) after drying to prepare a mesoporous cobalt-zirconia catalyst in which the platinum was added by 1% relative to the weight of the catalyst by wet impregnation. The catalyst powder mixed with the platinum precursor solution was slowly dried for about 12 hours in an oven at 80 C. to evaporate distilled water, which is the solvent. The catalyst was collected after drying and calcined by raising the heating temperature to 550 C. at a heating speed of 1 C./min and maintaining the temperature for 3 hours to obtain an Al.sub.2O.sub.3(5)-Pt(1)/meso-CoZr.sub.0.25O.sub.x catalyst. It was confirmed that the specific surface area of the catalyst prepared was 55.0 m.sup.2/g and the average pore size was 7.2 nm.

Example 5

Preparation of Al.SUB.2.O.SUB.3.(5)/Meso-CoAl.SUB.0.125.O.SUB.x .Catalyst

[0097] (1) Step 1: Preparation of Mesoporous Cobalt-Alumina Catalyst (Meso-CoAl.sub.0.125O.sub.x)

[0098] The mesoporous cobalt-alumina catalyst (meso-CoAl.sub.0.125O.sub.x) was obtained in the same way as described in Example 1 except that 1.6 g of aluminum nitrate nonahydrate (98.0%) was used.

[0099] (2) Step 2: Preparation of Al.sub.2O.sub.3(5)/Meso-CoAl.sub.0.125O.sub.x

[0100] The Al.sub.2O.sub.3(5)/meso-CoAl.sub.0.125O.sub.x catalyst was obtained in the same way as described in Example 2 except that the mesoporous cobalt-alumina catalyst (meso-CoAl.sub.0.125O.sub.x) prepared in step (1) above was used instead of an Al.sub.2O.sub.3(5)/meso-CoZr.sub.0.125O.sub.x catalyst.

[0101] It was confirmed that the specific surface area of the catalyst prepared was 68.1 m.sup.2/g and the average pore size was 4.7 nm.

Example 6

Preparation of Al.SUB.2.O.SUB.3.(5)/Meso-CoAl.SUB.0.25.O.SUB.x .Catalyst

[0102] (1) Step 1: Preparation of Mesoporous Cobalt-Alumina Catalyst (Meso-CoAl.sub.0.25O.sub.x)

[0103] The mesoporous cobalt-alumina catalyst (meso-CoAl.sub.0.25O.sub.x) was obtained in the same way as described in Example 1 except that 3.2 g of the aluminum nitrate nonahydrate was used.

[0104] (2) Step 2: Preparation of Al.sub.2O.sub.3(5)/Meso-CoAl.sub.0.25O.sub.x

[0105] The Al.sub.2O.sub.3(5)/meso-CoAl.sub.0.25O.sub.x catalyst was obtained in the same way as described in Example 2 except that the mesoporous cobalt-alumina (meso-CoAl.sub.0.25O.sub.x) prepared in step (1) above was used instead of an Al.sub.2O.sub.3(5)/meso-CoZr.sub.0.125O.sub.x catalyst.

[0106] It was confirmed that the specific surface area of the catalyst prepared was 46.9 m.sup.2/g and the average pore size was 5.5 nm.

Comparative Example 1

Preparation of Mesoporous Cobalt Catalyst (Meso-Co.SUB.3.O.SUB.4.)

[0107] The mesoporous cobalt catalyst (meso-Co.sub.3O.sub.4) was obtained in the same way as described in Example 1 except that 9.5 g of cobalt nitrate hexahydrate, which is a cobalt precursor, was used without a zirconium precursor. It was confirmed that the specific surface area of the catalyst prepared was 104 m.sup.2/g and the average pore size was 5.0 nm.

Comparative Example 2

Preparation of Al.SUB.2.O.SUB.3.(5)/Meso-CoZr.SUB.0.375.O.SUB.x .Catalyst

[0108] (1) Step 1: Preparation of Mesoporous Cobalt-Zirconia Catalyst (Meso-CoZr.sub.0.375O.sub.x)

[0109] The mesoporous cobalt-zirconia catalyst (meso-CoZr.sub.0.375O.sub.x) was obtained in the same way as described in Example 1 except that 3.4 g of zirconium nitrate oxide dehydrate was used instead of 2.3 g of the same.

[0110] (2) Step 2: Preparation of Al.sub.2O.sub.3(5)/Meso-CoZr.sub.0.375O.sub.x Catalyst

[0111] The Al.sub.2O.sub.3(5)/meso-CoZr.sub.0.375O.sub.x catalyst was obtained in the same way as described in Example 1 except that the mesoporous cobalt-zirconia catalyst (meso-CoZr.sub.0.375O.sub.x) prepared in step (1) was used instead of the meso-CoZr.sub.0.25O.sub.x catalyst.

[0112] It was confirmed that the specific surface area of the catalyst prepared was 21.2 m.sup.2/g and the average pore size was 4.9 nm.

Comparative Example 3

Preparation of Al.SUB.2.O.SUB.3.(5)/Meso-CoZr.SUB.0.5.O.SUB.x .Catalyst

[0113] (1) Step 1: Preparation of Mesoporous Cobalt Zirconia Catalyst (Meso-CoZr.sub.0.5O.sub.x)

[0114] The mesoporous cobalt-zirconia catalyst (meso-CoZr.sub.0.5O.sub.x) was obtained in the same way as described in Example 1 except that 4.6 g of zirconium nitrate oxide dehydrate was used instead of 2.3 g of the same.

[0115] (2) Step 2: Preparation of Al.sub.2O.sub.3(5)/Meso-CoZr.sub.0.5O.sub.x Catalyst

[0116] The Al.sub.2O.sub.3(5)/meso-CoZr.sub.0.5O.sub.x catalyst was obtained in the same way as described in Example 2 except that the mesoporous cobalt-zirconia catalyst (meso-CoZr.sub.0.5O.sub.x) prepared in step (1) above was used instead of the meso-CoZr.sub.0.25O.sub.x catalyst.

[0117] It was confirmed that the specific surface area of the catalyst prepared was 61.0 m.sup.2/g and the average pore size was 6.2 nm.

Comparative Example 4

Preparation of Al.SUB.2.O.SUB.3.(5)/Meso-CoAl.SUB.0.5.O.SUB.x .Catalyst

[0118] (1) Step 1: Preparation of Mesoporous Cobalt-Alumina Catalyst (Meso-CoAl.sub.0.5O.sub.x)

[0119] The mesoporous cobalt-alumina catalyst (meso-CoAl.sub.0.5O.sub.x) was obtained in the same way as described in Example 1 except that 6.5 g of the aluminum nitrate nonahydrate was used instead of 2.3 g of zirconium nitrate oxide dehydrate.

[0120] (2) Step 2: Preparation of Al.sub.2O.sub.3(5)/meso-CoAl.sub.0.5O.sub.x catalyst The Al.sub.2O.sub.3(5)/meso-CoAl.sub.0.5O.sub.x catalyst was obtained in the same way as described in Example 1 except that the mesoporous cobalt-alumina catalyst (meso-CoAl.sub.0.5O.sub.x) prepared in step (1) above was used instead of the meso-CoZr.sub.0.25O.sub.x catalyst.

Comparative Example 5

Preparation of Al.SUB.2.O.SUB.3.(5)/Meso-CoLa.SUB.0.5.O.SUB.x .Catalyst

[0121] (1) Step 1: Preparation of Mesoporous Cobalt-Lanthania Catalyst (Meso-CoLa.sub.0.5O.sub.x)

[0122] The mesoporous cobalt-lanthania catalyst (meso-CoLa.sub.0.5O.sub.x) was obtained in the same way as described in Example 1 except that 7.4 g of lanthanum nitrate hexahydrate (99.99%) was used instead of 2.3 of zirconium nitrate oxide dehydrate.

[0123] (2) Step 2: Preparation of Al.sub.2O.sub.3(5)/Meso-CoLa.sub.0.5O.sub.x Catalyst

[0124] The Al.sub.2O.sub.3(5)/meso-CoLa.sub.0.5O.sub.x catalyst was obtained in the same way as described in Example 1 except that the mesoporous cobalt-lanthania catalyst (meso-CoLa.sub.0.5O.sub.x) prepared in step (1) above was used instead of the meso-CoZr.sub.0.25O.sub.x catalyst.

Comparative Example 6

Preparation of Al.SUB.2.O.SUB.3.(5)/Meso-CoSm.SUB.0.25.O.SUB.x .Catalyst

[0125] (1) Step 1: Preparation of Mesoporous Cobalt-Samaria Catalyst (Meso-CoSm.sub.0.25O.sub.x)

[0126] The mesoporous cobalt-samaria catalyst (meso-CoSm.sub.0.25O.sub.x) was obtained in the same way as described in Example 1 except that 3.8 g of samarium nitrate hexahydrate (99.9%) was used instead of 2.3 of zirconium nitrate oxide dehydrate.

[0127] (2) Step 2: Preparation of Al.sub.2O.sub.3(5)/Meso-CoSm.sub.0.25O.sub.x Catalyst

[0128] The Al.sub.2O.sub.3(5)/meso-CoSm.sub.0.25O.sub.x catalyst was obtained in the same way as described in Example 2 except that the mesoporous cobalt-samaria catalyst (meso-CoSm.sub.0.25O.sub.x) prepared in step (1) above was used instead of the meso-CoZr.sub.0.25O.sub.x catalyst.

Comparative Example 7

Preparation of Al.SUB.2.O.SUB.3.(5)/Meso-CoMn.SUB.0.25.O.SUB.x .Catalyst

[0129] (1) Step 1: Preparation of Mesoporous Cobalt-Manganese Oxide Catalyst (Meso-CoMn.sub.0.25O.sub.x)

[0130] The mesoporous cobalt-manganese oxide catalyst (meso-CoMn.sub.0.25O.sub.x) was obtained in the same way as described in Example 1 except that 1.7 g of manganese chloride tetrahydrate (99.0%) was used instead of 2.3 of zirconium nitrate oxide dehydrate.

[0131] (2) Step 2: Preparation of Al.sub.2O.sub.3(5)/meso-CoMn.sub.0.25O.sub.x catalyst The Al.sub.2O.sub.3(5)/meso-CoMn.sub.0.25O.sub.x catalyst was obtained in the same way as described in Example 2 except that the mesoporous cobalt-manganese oxide catalyst (meso-CoMn.sub.0.25O.sub.x) prepared in step (1) above was used instead of the meso-CoZr.sub.0.25O.sub.x catalyst.

Experimental Example

[0132] In order to confirm the activity of the catalysts prepared in Examples 1 to 6 and Comparative Examples 1 to 7 for the low-temperature Fischer-Tropsch synthesis, the CO conversion and hydrocarbon selectivity were repeatedly analyzed. [0133] The reaction was carried out using syngas with a volume fraction of H.sub.2/N.sub.2/CO=62.84/5.60/31.56 with reaction conditions of T=230 C. to 250 C., P=20 bar, the space velocity of 8000 L/kg.Math.cat./h to 24,000 L/kg.Math.cat./h for 60 hours, and the activity of the catalysts were measured by the average after the reaction time of 50 hours.

Degree of deactivation (%)=[CO conversion(maximum)CO conversion(50 hours)]/CO conversion(maximum)100

Experimental Example 1

[0134] Reaction experiments were performed using the catalysts prepared in Examples 1 to 3, 5, and 6 and Comparative Examples 1 and 2.

[0135] Prior to the activity tests, the catalysts were reduced at 400 C. for 12 hours under reducing gas of H.sub.2(5%)/N.sub.2 at a flow rate of 33 cm.sup.3/min.

[0136] 0.1 g of the prepared catalyst and 1.0 of common puralox -Al.sub.2O.sub.3 as a diluent were mixed and placed in a fixed-bed reactor in which the pressure was 20 bar based on the pressure of the syngas, the space velocity as 24000 L/kg.Math.cat./h, and the temperature was 240 C., under the flow of syngas (H.sub.2+CO) at a flow rate of 39.999 ml/min, and the reaction experiments were thereby performed (refer to Table 1). The reaction was a continuous reaction which was carried out for about 60 hours, and the CO conversion and hydrocarbon selectivity for the reaction products were repeatedly analyzed using gas chromatography at 1 hour intervals. The results are shown in Table 2 below.

TABLE-US-00001 TABLE 1 Flow rate Space velocity Temperature of Dilution ratio of syngas (L/kg .Math. cat./h) fixed-bed reactor ( C.) (catalyst:diluent) (ml/min) 24000 240 1:10 39.999

TABLE-US-00002 TABLE 2 CO conversion (carbon mole %)* Carbon selectivity After 50 Degree of C.sub.1/C.sub.2-C.sub.4/C.sub.5+ hours of deactivation (carbon mole %) Catalyst maximum reaction (%)** (average) Example 1 meso-CoZr.sub.0.25O.sub.x 100.0 100.0 0.0 8.6/7.5/79.5 Example 2 Al.sub.2O.sub.3(5)/ 99.8 95.6 4.2 12.5/9.2/75.9 meso-CoZr.sub.0.125O.sub.x Example 3 Al.sub.2O.sub.3(5)/ 100.0 100.0 0.0 9.4/6.8/80.1 meso-CoZr.sub.0.25O.sub.x Example 5 Al.sub.2O.sub.3(5)/ 97.9 90.5 7.6 6.3/5.4/87.5 meso-CoAl.sub.0.125O.sub.x Example 6 Al.sub.2O.sub.3(5)/ 100.0 84.8 15.2 12.2/8.9/77.7 meso-CoAl.sub.0.25O.sub.x Comparative meso-Co.sub.3O.sub.4 99.5 27.8 72.1 5.0/10.0/85.0 Example 1 Comparative Al.sub.2O.sub.3(5)/ 7.2 2.8 61.1 19.9/17.6/62.5 Example 2 meso-CoZr.sub.0.375O.sub.x

Experimental Example 2

[0137] Reaction experiments were performed using the catalyst prepared in Example 3 above.

[0138] The CO conversion and hydrocarbon selectivity for the catalyst were repeatedly analyzed in the same way as described in Experimental Example 1 except for the conditions shown in Table 3. The results are shown in Table 4.

TABLE-US-00003 TABLE 3 Flow rate Space velocity Temperature of fixed- Dilution ratio of syngas (L/kg .Math. cat./h) bed reactor ( C.) (catalyst:diluent) (ml/min) 24000 230 1:10 39.999

TABLE-US-00004 TABLE 4 CO conversion Carbon (carbon selectivity mole %)* C.sub.1/C.sub.2-C.sub.4/C.sub.5+ After 50 Degree of (carbon max- hours of deactivation mole %) catalyst imum reaction (%)** (average) Exam- Al.sub.2O.sub.3(5)/ 100.0 99.9 0.1 8.2/5.9/83.2 ple meso- 3 CoZr.sub.0.25O.sub.x

Experimental Example 3

[0139] Reaction experiments were performed using the catalyst prepared in Example 3 above.

[0140] The CO conversion and hydrocarbon selectivity for the catalyst were repeatedly analyzed in the same way as described in Experimental Example 1 except for the conditions shown in Table 5. The results are shown in Table 6.

TABLE-US-00005 TABLE 5 Flow rate Space velocity Temperature of Dilution ratio of syngas (L/kg .Math. cat./h) fixed-bed reactor ( C.) (catalyst:diluent) (ml/min) 24000 230 1:1 39.999

TABLE-US-00006 TABLE 6 CO conversion (carbon mole %)* Carbon selectivity After 50 Degree of C.sub.1/C.sub.2-C.sub.4/C.sub.5+ hours of deactivation (carbon mole %) catalyst maximum reaction (%)** (average) Example 3 Al.sub.2O.sub.3(5)/ 98.8 70.3 28.8 8.5/17.4/74.1 meso-CoZr.sub.0.25O.sub.x

Experimental Example 4

[0141] Reaction experiments were performed using the catalysts prepared in Examples 3 and 4 above.

[0142] The CO conversion and hydrocarbon selectivity for the catalysts were repeatedly analyzed in the same way as described in Experimental Example 1 except for the conditions shown in Table 7. The results are shown in Table 8.

TABLE-US-00007 TABLE 7 Flow rate Space velocity Temperature of fixed- Dilution ratio of syngas (L/kg .Math. cat./h) bed reactor ( C.) (catalyst:diluent) (ml/min) 16000 230 1:1 26.666

TABLE-US-00008 TABLE 8 CO conversion (carbon mole %)* Carbon selectivity After 50 Degree of C.sub.1/C.sub.2-C.sub.4/C.sub.5+ hours of deactivation (carbon mole %) catalyst maximum reaction (%)** (average) Example 3 Al.sub.2O.sub.3(5)/ 99.6 98.0 1.6 12.5/19.7/67.8 meso-CoZr.sub.0.25O.sub.x Example 4 Al.sub.2O.sub.3(5)-Pt(1)/ 98.8 75.5 23.6 8.3/17.5/74.2 meso-CoZr.sub.0.25O.sub.x

Experimental Example 5

[0143] Reaction experiments were performed using the catalysts prepared in Examples 3 and 6, and Comparative Examples 3 to 5 above.

[0144] The CO conversion and hydrocarbon selectivity for the catalysts were repeatedly analyzed in the same way as described in Experimental Example 1 except for the conditions shown in Table 9. The results are shown in Table 10.

TABLE-US-00009 TABLE 9 Flow rate Space velocity Temperature of fixed- Dilution ratio of syngas (L/kg .Math. cat./h) bed reactor ( C.) (catalyst:diluent) (ml/min) 8000 250 1:1 13.333

TABLE-US-00010 TABLE 10 CO conversion (carbon mole %)* Carbon selectivity After 50 Degree of C.sub.1/C.sub.2-C.sub.4/C.sub.5+ hours of deactivation (carbon mole %) catalyst maximum reaction (%)** (average) Example 3 Al.sub.2O.sub.3(5)/ 99.9 99.8 0.1 12.1/12.0/75.9 meso-CoZr.sub.0.25O.sub.x Example 6 Al.sub.2O.sub.3(5)/ 99.9 98.8 0.1 15.8/11.9/72.3 meso-CoAl.sub.0.25O.sub.x Comparative Al.sub.2O.sub.3(5)/ 20.2 12.9 36.1 3.9/17.1/79.0 Example 3 meso-CoZr.sub.0.5O.sub.x Comparative Al.sub.2O.sub.3(5)/ 28.3 13.5 52.2 4.8/21.0/74.2 Example 4 meso-CoAl.sub.0.5O.sub.x Comparative Al.sub.2O.sub.3(5)/ 40.7 11.8 71.0 1.9/13.1/85.0 Example 5 meso-CoLa.sub.0.5O.sub.x

Experimental Example 6

[0145] Reaction experiments were performed using the catalysts prepared in Comparative Examples 6 to 7 above.

[0146] The CO conversion and hydrocarbon selectivity for the catalysts were repeatedly analyzed in the same way as described in Experimental Example 1 except for the conditions shown in Table 11. The results are shown in Table 12.

TABLE-US-00011 TABLE 11 Flow rate Space velocity Temperature of fixed- Dilution ratio of syngas (L/kg .Math. cat./h) bed reactor ( C.) (catalyst:diluent) (ml/min) 24000 250 1:10 39.999

TABLE-US-00012 TABLE 12 CO conversion (carbon mole %)* Carbon selectivity After 50 Degree of C.sub.1/C.sub.2-C.sub.4/C.sub.5+ hours of deactivation (carbon mole %) catalyst maximum reaction (%)** (average) Comparative Al.sub.2O.sub.3(5)/ 9.7 6.5 33.0 9.7/13.8/76.5 Example 6 meso-CoSm.sub.0.25O.sub.x Comparative Al.sub.2O.sub.3(5)/ 3.4 2.3 32.4 20.6/29.0/50.4 Example 7 meso-CoMn.sub.0.25O.sub.x

[0147] Upon overall review of Experimental Examples 1 to 6 above, in the cases where the mesoporous cobalt oxide catalysts, in which a non-reducing oxide was substituted in the mesoporous framework, were prepared (meso-CoM.sub.y(M=Zr or Al)O.sub.x) and where the mesoporous cobalt oxide catalysts, which were impregnated to contain Al.sub.2O.sub.3 in an amount of 2 wt % to 12 wt %, were prepared (Al.sub.2O.sub.3(5)/meso-CoM.sub.yO.sub.x(M=Zr or Al)O.sub.x), a high CO conversion and low degree of deactivation were seen in most cases, as shown in Tables 2, 4, 6, 8, 10, and 12.

[0148] In contrast, even when a non-reducing oxide was not substituted in the mesoporous framework as in the meso-Co.sub.3O.sub.4 catalyst of Comparative Example 1, it was confirmed through experiments that the deactivation of the catalyst occurred rapidly due to collapse of the mesostructure during the reduction or reaction.

[0149] Therefore, when a non-reducing oxide (zirconia, alumina) was substituted with the mesoporous framework and the surface of the catalyst was impregnated with Al.sub.2O.sub.3, compared to the mesoporous cobalt catalyst which was simply prepared (Comparative Example 1), the mesoporous structure could be maintained even under a reducing atmosphere, and thus the activity of the catalyst could be stably secured.

[0150] Further, in the case of the mesoporous cobalt-metal oxide catalysts, CoM.sub.aO.sub.b (M is Zr or Al, a or b is a molar ratio, wherein a and b are in the range of 0.1a0.35 and 1b4, respectively), which was prepared to prevent collapse of the mesostructure by adding aluminum oxide or zirconium oxide, etc., as a non-reducing oxide during the preparation process thereof, when a was within the above range, the catalysts (Examples 1 to 6) showed excellent activity and stability compared to the catalysts wherein a was a value outside of the range (Comparative Examples 2 to 4).

[0151] In addition, it was confirmed that even when lanthanum (La), manganese (Mn), samarium (Sm), etc. were used as the non-reducing oxide (Comparative Examples 5 to 7), the activity and the stability of the catalysts of the present invention could not be secured.