POROUS CARBON CATALYST LOADED WITH METAL SULFIDES BASED ON HIGH-SULFUR PETROLEUM COKE AND PREPARATION METHOD THEREFOR AND APPLICATION THEREOF

Abstract

The present invention provides a porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke and preparation method therefor and application thereof. The method includes the steps of preparing an in-situ activated precursor from a pre-treated high-sulfur petroleum coke, destabilizing bulk sulfur, conducting an in-situ metal-sulfur bonding reaction, and washing and drying, which achieve the high-value in-situ conversion of sulfur in high-sulfur petroleum coke, resulting in the preparation of a porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke. This catalyst is applied to catalyze magnesium-based hydrogen storage materials. It not only avoids the discharge of sulfur-containing gas or sulfur-containing wastewater in the conventional utilization route of high-sulfur petroleum coke, but also expands the green multi-scenario utilization route of high-sulfur petroleum coke to promote the synergy of pollution reduction and carbon reduction in the petroleum refining industry.

Claims

1. A method for preparing a porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke, comprising: (1) preparing an in-situ activated precursor: mixing a high-sulfur petroleum coke having a content of sulfur of 3-10 wt % with a transition metal salt in an ethanol aqueous solution thoroughly, and then evaporating and drying to obtain the in-situ activated precursor; the transition metal of the salt is nickel or niobium; (2) destabilizing bulk sulfur: grinding and mixing the in-situ activated precursor obtained from step (1) with an alkaline activator in a mass ratio of the alkaline activator to the high-sulfur petroleum coke of (1-5):(1-2), followed by placement in a tube furnace, heating from room temperature to a specified temperature of 600-800 C. at a controlled rate under an argon inert atmosphere, bulk sulfur is destabilized under the joint action of the specified temperature and alkaline activator; the alkaline activator is potassium hydroxide or sodium hydroxide; (3) conducting an in-situ metal-sulfur bonding reaction: maintaining the specified temperature from step (2), switching the argon atmosphere to hydrogen at a flow rate of 10-60 mL/min, and conducting the in-situ metal-sulfur bonding reaction for 1-2 hours, followed by cooling down to room temperature under an argon atmosphere; (4) washing and drying: washing the product obtained from step (3) with a washing solution, drying and grinding to obtain the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke.

2. The method according to claim 1, wherein a particle size of the high-sulfur petroleum coke is 110-125 m.

3. The method according to claim 1, wherein the transition metal salt is selected from at least one of nitrates, sulfates, chlorides, and acetates; and a mass ratio of the high-sulfur petroleum coke to the transition metal salt is 1:(0.1-1).

4. (canceled)

5. The method according to claim 1, wherein the controlled rate is 5-10 C./min.

6. The method according to claim 1, wherein in the step of washing and drying, the washing solution is water, a pH of the product after washing is 6.5-7.5, and the drying is carried out at 60-80 C. for 20-24 hours.

7. A porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke, being prepared by a method according to claim 1.

8. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings to the specification, which form part of the present invention, are used to provide a further understanding of the present invention, and the illustrative examples of the present invention and the description thereof are used to explain the present invention and are not unduly limiting the present invention.

[0041] FIG. 1 is a process flow diagram for the preparation method of the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke, according to the present invention.

[0042] FIG. 2 is X-ray diffraction (XRD) pattern of the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke prepared in Example 1.

[0043] FIG. 3 shows N.sub.2 adsorption/desorption isotherms of the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke prepared in Example 1.

[0044] FIG. 4 is X-ray diffraction (XRD) pattern of the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke prepared in Example 3.

[0045] FIG. 5 shows N.sub.2 adsorption/desorption isotherms of the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke prepared in Example 3.

[0046] FIG. 6 shows the DSC curve of hydrogen release from MgH.sub.2 catalyzed by the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke, prepared in Example 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] It should be noted that the following detailed descriptions are all illustrative and intended to provide further clarification of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs.

[0048] The present invention will be further described below in conjunction with the following examples.

[0049] The materials used in the examples and comparative examples were commercially available unless otherwise specified.

Example 1

[0050] A method for preparing aporous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke is illustrated in the flowchart shown in FIG. 1. The method included the following steps:

Step 1: Preparation of the In-Situ Activated Precursor

[0051] (1) 1.5 g of high-sulfur petroleum coke was uniformly dispersed in 75 ml of an ethanol solution with a volume fraction of 50%, and 1.01 g of nickel nitrate hexahydrate was added. The mixture was stirred at room temperature for 2 hours. [0052] (2) After stirring, the high-sulfur petroleum coke-metal salt solution was placed in a drying oven and evaporated at 120 C. for 12 hours to obtain the activated precursor.

Step 2: Destabilization of Bulk Sulfur

[0053] (1) The potassium hydroxide and the activated precursor from Step 1 were ground evenly in a mortar at a mass ratio of 1:1 and placed in a nickel crucible. [0054] (2) The nickel crucible was placed in a high-temperature tube furnace. Under a high-purity argon atmosphere, the temperature was increased at a rate of 5 C./min to 800 C.

Step 3: In-Situ Metal-Sulfur Bonding Reaction

[0055] (1) Once the temperature reached 800 C., the atmosphere was switched to hydrogen at a flow rate of 25 mL/min. [0056] (2) The reaction was maintained at this temperature for 1 hour to conduct the in-situ metal-sulfur bonding reaction, and then the temperature was reduced to room temperature under an argon atmosphere.

Step 4: Washing and Drying

[0057] (1) The sample obtained from Step 3 was washed with deionized water until the pH value reached 7. [0058] (2) The washed sample was dried in a drying oven at 70 C. for 24 hours, yielding a porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke.

[0059] FIG. 2 shows the XRD pattern of the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke prepared in Example 1, where diffraction peaks corresponding to Ni.sub.2S.sub.3 appeared at several positions, confirming the successful formation of the transition metal sulfide. Table 1 shows that the sulfur conversion rate of the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke was 40%, indicating that the bulk sulfur in high-sulfur petroleum coke was successfully retained and transformed into an effective catalytic component.

[0060] FIG. 3 shows the N.sub.2 adsorption/desorption isotherms of the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke, exhibiting a typical Type I isotherm, with a specific surface area and pore volume of 600.21 m.sup.2/g and 0.347 cm.sup.2/g, respectively.

Example 2

[0061] The method for preparing the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke in this example was the same as Example 1, except for Steps 1 and 2. [0062] Step 1: Preparation of the In-Situ Activated Precursor [0063] (1) 1.5 g of high-sulfur petroleum coke was uniformly dispersed in 75 ml of an ethanol solution with a volume fraction of 50%, and 0.93 g of niobium pentachloride was added. The mixture was stirred at room temperature for 2 hours. [0064] (2) After stirring, the high-sulfur petroleum coke-metal salt solution was placed in a drying oven and evaporated at 120 C. for 12 hours to obtain the activated precursor.

Step 2: Destabilization of Bulk Sulfur

[0065] (1) The potassium hydroxide and the activated precursor from Step 1 were ground evenly in a mortar at a mass ratio of 2:1 and placed in a nickel crucible. [0066] (2) The nickel crucible was placed in a high-temperature tube furnace. Under a high-purity argon atmosphere, the temperature was increased at a rate of 5 C./min to 800 C.

Example 3

[0067] The method for preparing the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke in this example was the same as Example 1, except for Steps 1 and 2.

Step 1: Preparation of the In-Situ Activated Precursor

[0068] (1) 2 g of high-sulfur petroleum coke was uniformly dispersed in 100 ml of an ethanol solution with a volume fraction of 50%, and 1.35 g of nickel nitrate hexahydrate was added. The mixture was stirred at room temperature for 2 hours. [0069] (2) After stirring, the high-sulfur petroleum coke-metal salt solution was placed in a drying oven and evaporated at 120 C. for 12 hours to obtain the activated precursor.

Step 2: Destabilization of Bulk Sulfur

[0070] (1) The potassium hydroxide and the activated precursor from Step 1 were ground evenly in a mortar at a mass ratio of 2:1 and placed in a nickel crucible. [0071] (2) The nickel crucible was placed in a high-temperature tube furnace. Under a high-purity argon atmosphere, the temperature was increased at a rate of 5 C./min to 800 C.

[0072] FIG. 4 shows the XRD pattern of the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke prepared in Example 3, where diffraction peaks corresponding to Ni.sub.2S.sub.3 were detected at several positions at 20 values of 31.1, 37.1, 43.2, 50.1, and 62.9.

[0073] Table 1 shows that the sulfur conversion rate of the prepared catalyst was 25.11%.

[0074] FIG. 5 shows the N.sub.2 adsorption/desorption isotherms of the prepared catalyst, which exhibited a typical Type I isotherm. The rapid rise in adsorption at low relative pressures and the adsorption capacity remained stable subsequently. The plateau parallel to the P/P.sub.0 axis indicated the microporous nature of the prepared catalyst material. The specific surface area and pore volume were 1289.57 m.sup.2/g and 0.707 cm.sup.2/g, respectively.

Comparative Example 1

[0075] The difference from Example 3 was that Step 3 used an argon atmosphere at a flow rate of 25 ml/min instead of switching to hydrogen, while all other conditions remained the same as in Example 3.

Comparative Example 2

[0076] The difference from Example 3 was that no nickel nitrate hexahydrate was added in Step 1, while all other conditions remained the same as in Example 3.

Comparative Example 3

[0077] The differences from Example 3 were that Step 3 used an argon atmosphere instead of switching to hydrogen, and no nickel nitrate hexahydrate was added in Step 1. All other conditions remained the same as in Example 3.

[0078] Table 1 shows the total sulfur content and sulfur conversion rates of the catalysts prepared in Examples 1-3 and Comparative Examples 1-3. The method in Example 1 achieved a sulfur conversion rate of 40%. By comparing with the comparative examples, it is evident that both hydrogen and the metal salt precursor play crucial roles in the preparation of the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke, and neither can be omitted.

TABLE-US-00001 TABLE 1 Total sulfur content and sulfur conversion rates of catalysts prepared in Examples 1-3 and Comparative Examples 1-3 Total sulfur content Sulfur conversion rate Sample (ad %) (%) Example 1 2.96 40.00 Example 2 2.08 28.11 Example 3 1.94 26.22 Comparative 0.11 4.19 Example 1 Comparative 0.12 1.62 Example 2 Comparative 0.61 8.24 Example 3

[0079] In Table 1, the total sulfur content refers to the mass percentage of sulfur in the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke; the sulfur conversion rate refers to the rate at which bulk sulfur atoms in the high-sulfur petroleum coke are in situ converted into transition metal sulfides.

[0080] The porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke, prepared in Example 3, was mixed with MgH.sub.2 at a mass ratio of 1:10 and ball-milled. The ball-to-material ratio was 40:1, the ball-milling speed was 400 rpm, and the ball-milling time was 5 hours. Under a high-purity argon protective atmosphere, the temperature was increased at a rate of 10 C./min, and the hydrogen desorption peak temperature was measured using differential scanning calorimetry (DSC).

[0081] FIG. 6 shows the hydrogen desorption curve of the composite hydrogen storage material (TMS-AC-MgH.sub.2), composed of the porous carbon catalyst loaded with metal sulfides based on high-sulfur petroleum coke and MgH.sub.2, prepared in Example 3. The peak hydrogen desorption temperature of the composite hydrogen storage material was 330 C., which is 100 C. lower than that of pure MgH.sub.2, indicating significant catalytic activity.

[0082] These results demonstrate that the method described in the present invention successfully in situ bonded and converted sulfur in high-sulfur petroleum coke into corresponding transition metal sulfides, achieving the resource utilization of sulfur in high-sulfur petroleum coke. The activation effect of KOH formed a porous structure that allowed the even dispersion of the produced metal sulfide catalyst, effectively improving the hydrogen desorption performance of magnesium hydride.

[0083] The above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principles of the present invention should be included within the scope of the present invention's protection.