Sulfur-resistant catalyst for aromatics saturated hydrogenation and preparation method thereof

Abstract

The present invention relates to a method for preparing a sulfur-resistant catalyst for aromatics saturated hydrogenation, comprising the steps of: preparing noble metal impregnation solutions from a noble metal and deionized water or an acid solution; impregnating a carrier with the impregnation solutions sequentially from high to low concentrations by incipient impregnation; homogenizing, drying, and calcinating to obtain the sulfur-resistant catalyst for aromatics saturated hydrogenation. The catalyst for aromatics saturated hydrogenation prepared by the method according to the present invention is primarily used in processing low-sulfur and high-aromatics light distillate, middle distillate, atmospheric gas oil, and vacuum gas oil. The method according to the present invention is advantageous in that the catalyst for aromatics saturated hydrogenation exhibits good hydrofining performance, superior aromatics saturation performance, high liquid yield of products, as well as excellent desulfurization and sulfur-resistance, and the catalyst has remarkable effects in use and a great prospect of application.

Claims

1. A method for preparing a sulfur-resistant catalyst for aromatics saturated hydrogenation, comprising the steps of: (1) preparing noble metal impregnation solutions from a noble metal and deionized water or an acid solution, wherein said noble metal impregnation solutions range from high to low concentration; (2) impregnating a carrier consisting of an inorganic porous material with the impregnation solutions by incipient impregnation; and (3) homogenizing for 10 min to 3 h, drying at 90 to 140 C. for 3 to 6 h, and calcinating at 350 to 650 C. for 3 to 10 h to obtain a sulfur-resistant catalyst for aromatics saturated hydrogenation; characterized in that, during the impregnation in the above step (2), the carrier is impregnated sequentially with the impregnation solutions from high to low concentrations.

2. The method for preparing a sulfur-resistant catalyst for aromatics saturated hydrogenation according to claim 1, characterized in that the inorganic porous material is comprised of alumina and at least one selected from the group consisting of silica, titania-zirconia, alumina-silica, and alumina-zirconia.

3. The method for preparing a sulfur-resistant catalyst for aromatics saturated hydrogenation according to claim 1, characterized in that the carrier has a specific surface area of 150 to 500 m.sup.2/g and a pore volume of 0.2 to 0.7 cm.sup.3/g.

4. The method for preparing a sulfur-resistant catalyst for aromatics saturated hydrogenation according to claim 3, characterized in that the carrier has a specific surface area of 200 to 400 m.sup.2/g and a pore volume of 0.3 to 0.6 cm.sup.3/g.

5. The method for preparing a sulfur-resistant catalyst for aromatics saturated hydrogenation according to claim 2, characterized in that the mass ratio of aluminum to silicon (in terms of alumina to silica) is 1:10 to 10:1 when the inorganic porous material is comprised of alumina and at least one selected from the group consisting of silica and alumina-silica; the mass ratio of aluminum to zirconium (in terms of alumina to zirconia) is 1:20 to 20:1 when the inorganic porous material is comprised of alumina and at least one selected from the group consisting of titania-zirconia and alumina-zirconia.

6. The method for preparing a sulfur-resistant catalyst for aromatics saturated hydrogenation according to claim 1, characterized in that the noble metal is selected from at least one from the group consisting of Pt, Pd, Ru, Rh, Re, and Ir compounds, and the mass fraction of the noble metal contained in the catalyst is 0.05 to 5.0 wt %.

7. The method for preparing a sulfur-resistant catalyst for aromatics saturated hydrogenation according to claim 6, characterized in that the noble metal is one or two of the Pt, Pd, Ru, and Re compounds, and the mass fraction of the noble metal contained in the catalyst is 0.2 to 2.0 wt %.

8. The method for preparing a sulfur-resistant catalyst for aromatics saturated hydrogenation according to claim 6, characterized in that the noble metal is Pt and Pd, and the mass ratio of Pt to Pd contained in the catalyst is 1:6 to 6:1.

9. The method for preparing a sulfur-resistant catalyst for aromatics saturated hydrogenation according to claim 1, characterized in that the acid component in the acid solution is selected from at least one from the group consisting of hydrochloric acid, phosphoric acid, biphosphate, dihydric phosphate, sulfuric acid, bisulfate, acetic acid, citric acid, and nitric acid.

10. A sulfur-resistant catalyst for aromatics saturated hydrogenation prepared by the method for preparing a sulfur-resistant catalyst for aromatics saturated hydrogenation according claim 1, characterized in that the concentration of the noble metal component in the catalyst decreases from the center of the particle to the outer surface thereof, the ratio of the metal content at the circumcenter of the particle to the metal content on the circumcircle surface of the particle is 2.0 to 6.0, and the ratio of the metal content at 0.5 R to the metal content on the outer surface is 3.0 to 1.5, where the circumradius is R with the circumcenter of the cross section of the catalyst particle taken as the starting point.

11. The sulfur-resistant catalyst for aromatics saturated hydrogenation according to claim 10, characterized in that the noble metal is selected from at least one from the group consisting of Pt, Pd, Ru, Rh, Re, and Ir compounds, and the mass fraction of the noble metal contained in the catalyst is 0.05 to 5.0 wt %.

12. The sulfur-resistant catalyst for aromatics saturated hydrogenation according to claim 11, characterized in that the noble metal is one or two of the Pt, Pd, Ru, and Re compounds, and the mass fraction of the noble metal contained in the catalyst is preferably 0.2 to 2.0 wt %.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention.

(2) FIG. 1 is a schematic plot of the sulfur resistance and hydrodesulfurization performance of the catalysts prepared in Example 1, Example 3, Comparative Example 1 and Comparative Example 2.

(3) FIG. 2 is a schematic plot of the relative content distribution of the noble metal in the catalyst.

(4) FIG. 3 is a schematic plot of the relative content distribution of the noble metal in the catalyst.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(5) The present invention is now further described in details by referring to specific examples, but the present invention is not limited to the following Examples. Any modification without departing from the spirit and scope of the present invention falls within the scope of the present invention.

Example 1

(6) An inorganic porous material containing 96 wt % of Al.sub.2O.sub.3 and Al.sub.2O.sub.3SiO.sub.2 and 4 wt % ZrO.sub.2 in the carrier was mechanically kneaded into a carrier (the mass ratio of Al.sub.2O.sub.3 to SiO.sub.2 in the carrier was 10:1, and the mass ratio of Al.sub.2O.sub.3 to ZrO.sub.2 was 20:1), and then extruded, dried and calcinated to prepare the carrier final product.

(7) Incipient impregnation was employed to prepare the catalyst carrier with a water absorption of 0.89 ml/g. 200 g of the carrier was weighed and sprayed and impregnated with 78 ml of an impregnation solution containing 1.0 wt % PtCl.sub.2 and 0.3 wt % PdCl.sub.2. During the spray impregnation, 100 ml of an impregnation solution containing 0.2 wt % PtCl.sub.2, 0.1 wt % PdCl.sub.2, and an acid at a concentration of 0.2 mol/L (H.sub.3PO.sub.4+HCl) was dropped into the previous impregnation solution at a constant speed over 30 minutes. The catalyst was homogenized in the spray impregnation apparatus for 40 minutes, dried at 90 C. for 4 hours, and then calcinated at 550 C. for 6 hours to afford catalyst A-1.

Example 2

(8) An inorganic porous material containing 30 wt % of Al.sub.2O.sub.3 and SiO.sub.2, 45 wt % ZrO.sub.2, and 25 wt % ZrO.sub.2TiO.sub.2 in the carrier was mechanically kneaded into a carrier (the mass ratio of Al.sub.2O.sub.3 to SiO.sub.2 in the carrier was 1:10, and the mass ratio of Al.sub.2O.sub.3 to ZrO.sub.2 was 1:20), and then extruded, dried and calcinated to prepare the carrier final product.

(9) Incipient impregnation was employed to prepare the catalyst carrier with a water absorption of 0.89 ml/g. 200 g of the carrier was weighed and sprayed and impregnated with 78 ml of an impregnation solution containing 1.0 w % PtCl.sub.2 and 0.3 wt % PdCl.sub.2. During the spray impregnation, 100 ml of an impregnation solution containing 0.2 wt % PtCl.sub.2, 0.1 wt % PdCl.sub.2, and an acid at a concentration of 0.2 mol/L (nitric acid+citric acid) was dropped into the previous impregnation solution at a constant speed over 30 minutes. The catalyst was homogenized in the spray impregnation apparatus for 10 minutes, dried at 140 C. for 3 hours, and then calcinated at 500 C. for 8 hours to afford catalyst A-2.

Example 3

(10) An inorganic porous material containing 60 wt % of Al.sub.2O.sub.3 and Al.sub.2O.sub.3SiO.sub.2, 20 wt % ZrO.sub.2, and 20 wt % ZrO.sub.2TiO.sub.2 in the carrier was mechanically kneaded into a carrier (the mass ratio of Al.sub.2O.sub.3 to SiO.sub.2 in the carrier was 5:1, and the mass ratio of Al.sub.2O.sub.3 to ZrO.sub.2 was 5:1), and then extruded, dried and calcinated to prepare the carrier final product.

(11) Incipient impregnation was employed to prepare the catalyst carrier with a water absorption of 0.89 ml/g. 200 g of the carrier was weighed and sprayed and impregnated with 78 ml of an impregnation solution containing 1.0 wt % PtCl.sub.2 and 0.3 wt % PdCl.sub.2. During the spray impregnation, 100 ml of an impregnation solution containing 0.2 wt % PtCl.sub.2, 0.1 wt % PdCl.sub.2, and an acid at a concentration of 0.2 mol/L (H.sub.3PO.sub.4+HCl) was dropped into the previous impregnation solution at a constant speed over 30 minutes. The catalyst was homogenized in the spray impregnation apparatus for 3 hours, dried at 100 C. for 6 hours, and then calcinated at 650 C. for 3 hours to afford catalyst A-3.

Example 4

(12) An inorganic porous material containing 45 wt % of Al.sub.2O.sub.3ZrO.sub.2, 45 wt % Al.sub.2O.sub.3SiO.sub.2, and 10 wt % TiO.sub.2 in the carrier was mechanically kneaded into a carrier (the mass ratio of Al.sub.2O.sub.3 to SiO.sub.2 in the carrier was 1:1, and the mass ratio of Al.sub.2O.sub.3 to ZrO.sub.2 was 1:1), and then extruded, dried and calcinated to prepare the carrier final product.

(13) Incipient impregnation was employed to prepare the catalyst carrier with a water absorption of 0.89 ml/g. 200 g of the carrier was weighed and sprayed and impregnated with 78 ml of an impregnation solution containing 1.0 wt % PtCl.sub.2 and 0.3 wt % PdCl.sub.2. During the spray impregnation, 100 ml of an impregnation solution containing 0.2 wt % PtCl.sub.2, 0.1 wt % PdCl.sub.2, and an acid at a concentration of 0.3 mol/L (biphosphate+dihydric phosphate+acetic acid) was dropped into the previous impregnation solution at a constant speed over 30 minutes. The catalyst was homogenized in the spray impregnation apparatus for 50 minutes, dried at 90 C. for 5 hours, and then calcinated at 350 C. for 10 hours to afford catalyst A-4.

Example 5

(14) An inorganic porous material containing 50 wt % of Al.sub.2O.sub.3SiO.sub.2, 20 wt % Al.sub.2O.sub.3ZrO.sub.2, 10 wt % Al.sub.2O.sub.3, and 20 wt % Al.sub.2O.sub.3TiO.sub.2 in the carrier was mechanically kneaded into a carrier (the mass ratio of Al.sub.2O.sub.3 to SiO.sub.2 in the carrier was 3:1, and the mass ratio of Al.sub.2O.sub.3 to ZrO.sub.2 was 10:1), and then extruded, dried and calcinated to prepare the carrier final product.

(15) Incipient impregnation was employed to prepare the catalyst carrier with a water absorption of 0.89 ml/g. The remaining homogenization, drying and calcination steps were the same as in Example 1, except that a phosphoric acid+sulfuric acid+bisulfate mixed solution at a concentration of 0.25 mol/L was used as the acid solution in the impregnation step, to afford catalyst A-5.

Example 6

(16) With the exception that 100 ml of an impregnation solution containing 1.0 wt % PtCl.sub.2 and 0.3 wt % PdCl.sub.2 was sprayed and impregnated while 78 ml of an impregnation solution containing 0.2 wt % PtCl.sub.2, 0.1 wt % PdCl.sub.2, and an acid at a concentration of 0.2 mol/L (H.sub.3PO.sub.4+HCl) was dropped into the previous impregnation solution at a constant speed, the same remaining steps as in Example 1 were conducted to afford catalyst A-6.

Comparative Example 1

(17) With the exception that a carrier was prepared from Al.sub.2O.sub.3 raw material, and 200 g of the carrier was weighed and sprayed and impregnated with 178 ml of an impregnation solution containing 0.55 wt % PtCl.sub.2, 0.19 wt % PdCl.sub.2, and an acid at a concentration of 0.11 wt % (H.sub.3PO.sub.4+HCl), the same remaining steps as in Example 1 were conducted to afford catalyst B-1.

Comparative Example 2

(18) Catalyst B-2 was prepared in the same catalyst preparation process as in Comparative Example 1, with the exception that a carrier was prepared from SiO.sub.2 as raw material.

Example 7

(19) Catalysts A-1, A-2, A-3, A-4, A-5, A-6, B-1, and B-2 were characterized by using EDS characterization means.

(20) TABLE-US-00001 TABLE 1 Results of physical properties of the catalysts No. A-1 A-2 A-3 A-4 A-5 A-6 B-1 B-2 Pt + Pd(center)/Pt + Pd(outer surface) 3.5 Pt + Pd(0.5R)/Pt + Pd(outer surface) 1.8 Pt + Pd(center)/Pt + Pd(outer surface) 3.7 Pt + Pd(0.5R)/Pt + Pd(outer surface) 2.0 Pt + Pd(center)/Pt + Pd(outer surface) 2.9 Pt + Pd(0.5R)/Pt + Pd(outer surface) 1.6 Pt + Pd(center)/Pt + Pd(outer surface) 5.1 Pt + Pd(0.5R)/Pt + Pd(outer surface) 2.2 Pt + Pd(center)/Pt + Pd(outer surface) 4.1 Pt + Pd(0.5R)/Pt + Pd(outer surface) 2.4 Pt + Pd(center)/Pt + Pd(outer surface) 4.6 Pt + Pd(0.5R)/Pt + Pd(outer surface) 1.8 Pt + Pd(center)/Pt + Pd(outer surface) 0.91 Pt + Pd(0.5R)/Pt + Pd(outer surface) 0.94 Pt + Pd(center)/Pt + Pd(outer surface) 1.10 Pt + Pd(0.5R)/Pt + Pd(outer surface) 1.05 Note: R is the circumradius of the cross section of the catalyst particle, with the circumcenter of the cross section of the catalyst particle as the starting point.

(21) As seen in Table 1, in the catalysts A-1, A-2, A-3, A-4, A-5, and A-6 in the Examples, noble metals Pt and Pd show a trend of their contents decreasing in a gradient from inside to outside of the catalyst particle, as shown in FIG. 2 or FIG. 3; whereas, in the catalysts B-1 and B-2 in the Comparative Examples, noble metals Pt and Pd show a relative uniform distribution from inside to outside of the catalyst particle.

Example 8

(22) Actual assessment of raw material hydrogenation was conducted using A-1, A-3, B-1, and B-2 as exemplary catalysts.

(23) Hydrogenation assessment reaction was carried out on a 100 ml hydrogenation stationary bed, and the raw material oil for assessment was hydrogenated vacuum gas oil. The properties of raw material oil were shown in Table 2.

(24) TABLE-US-00002 TABLE 2 Properties of raw material oil Density (20 C.), g/cm.sup.3 0.8629 Distillation range HK, C. 357 50%, C. 510 KK, C. 553 Sulfur, g/g 63 Aromatics content, wt % 31.4

(25) Operating conditions for the assessment were shown in Table 3.

(26) TABLE-US-00003 TABLE 3 Operating conditions for the assessment Temperature, C. 286 Pressure, MPa 6.0 Liquid hourly mass space velocity, h.sup.1 0.75 Hydrogen/oil volume ratio 600

(27) Assessment results after the catalysts operated for 200 hours were shown in Table 4, and sulfur resistance and hydrodesulfurization performance of the catalysts were shown in FIG. 1.

(28) TABLE-US-00004 TABLE 4 Assessment results Analysis results Analysis items A-1 A-3 B-1 B-2 Liquid yield, wt % 99.3 99.0 98.6 98.1 Aromatics content, wt % <1 1.3 3.4 4.7

(29) As seen from the assessment results in Table 4, the catalyst for aromatics saturated hydrogenation prepared according to the present invention exhibits good refining performance, superior aromatics saturation performance, and high liquid yield, and is superior to the hydrogenation catalysts having a uniform distribution of active ingredients prepared by conventional methods. Also, as seen in FIG. 1, the catalyst for aromatics saturated hydrogenation prepared according to the present invention shows both superior hydrodesulfurization performance and excellent sulfur resistance, and is a potential catalyst for aromatics saturated hydrogenation.

EQUIVALENTS

(30) While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.