Alloy catalyst, its preparation method and application

Abstract

The application discloses an alloy catalyst and a preparation method and application thereof, which comprises a metal ball carrier and an active metal layer loaded on the surface of the metal ball carrier, and the mass percentage of the active metal is 0.0000001% to 7%; the active metal is selected from one or a combination of rhenium (Re), iron (Fe), ruthenium (Ru), iridium (Ir), rhodium (Rh), manganese (Mn), bismuth (Bi), nickel (Ni), platinum (Pt), tungsten (W), cobalt (Co), molybdenum (Mo) or chromium (Cr). The active metal element is directly deposited on the surface of the metal ball to form an alloy structure, so that the thermal stability and the anti-sintering capacity of the catalyst are effectively improved, and meanwhile, the reaction active center of the zero-dimensional catalyst is completely exposed to a reaction atmosphere, and the catalyst has high catalytic efficiency.

Description

Technical Field

[0001] This invention relates to the field of hydrocarbon cracking technology, specifically to an alloy catalyst, its preparation method, and its application. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Alkane cracking for hydrogen production is an ideal route. Compared to industrialized natural gas steam reforming, although both processes use natural gas as a reactant, alkane cracking produces no carbon emissions. The reaction products are hydrogen and solid carbon powder, offering advantages such as simple reaction processes and easy product separation. It can also help industries overcome the current predicament of producing "gray hydrogen." Currently, alkane cracking for hydrogen production faces two main challenges: one is improving the alkane cracking activity at low temperatures, as increasing the reaction temperature accelerates the sintering of active metals and reduces the lifespan of the cracking catalyst; the other is that traditional fixed-bed reactors cannot remove the carbon powder generated during the cracking reaction, leading to rapid deactivation of the cracking catalyst. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide an alloy catalyst, its preparation method and application.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] In a first aspect, the present invention provides an alloy catalyst comprising a metal ball support and an active metal layer supported on the surface of the metal ball support, wherein the mass percentage of the active metal is 0.0000001% to 7%.

[0007] The active metal is selected from one or a combination of rhenium (Re), iron (Fe), ruthenium (Ru), iridium (Ir), rhodium (Rh), manganese (Mn), bismuth (Bi), nickel (Ni), platinum (Pt), tungsten (W), cobalt (Co), molybdenum (Mo), or chromium (Cr).

[0008] In some embodiments, the metal spheres are made of one or more alloys selected from molybdenum (Mo), vanadium (V), cobalt (Co), nickel (Ni), iron (Fe), copper (Cu), bismuth (Bi), zinc (Zn), chromium (Cr), or manganese (Mn). The metal spheres, acting as a matrix, influence the catalytic activity of the alloy structure.

[0009] In some embodiments, the diameter of the metal ball is 1-10 mm.

[0010] In some embodiments, the active metal in the catalyst has a mass percentage of 0.0000001% to 3.2%.

[0011] Secondly, the present invention provides a method for preparing the catalyst for mechanocatalytic hydrocarbon cracking, comprising the following steps:

[0012] Clean metal balls are immersed in an active metal precursor solution, ultrasonically treated for a set time, and then dried.

[0013] The catalyst was prepared by calcining the dried metal spheres loaded with the precursor in static air and then reducing them at high temperature in a hydrogen atmosphere.

[0014] Ultrasonic treatment can improve the uniform dispersion of active metal ions and promote the rapid deposition of metal ions.

[0015] Calcination in static air can save on preparation costs, while introducing air during the calcination process will increase the difficulty and cost of preparation.

[0016] In some embodiments, the molar concentration of the active metal precursor solution is 0.001M to 1.5M.

[0017] In some embodiments, the calcination temperature is 200–500°C and the calcination time is 0.5–4 h.

[0018] Preferably, the reduction treatment temperature is 300–1000℃ and the reduction treatment time is 0.5–4h.

[0019] Thirdly, the present invention provides the application of the alloy catalyst in mechanical catalytic cracking of hydrocarbons to produce hydrogen and carbon black.

[0020] Fourthly, the present invention provides a method for producing hydrogen and carbon black by mechanical catalytic cracking of hydrocarbons, comprising the following steps:

[0021] The catalyst is loaded into a mechanical reactor, and hydrocarbons are introduced into it. The mechanical reactor reciprocates periodically, and the direct cracking of hydrocarbons to produce hydrogen and carbon black is achieved at 50–1000°C and 0.1–5 MPa.

[0022] In some embodiments, the hydrocarbon is methane, ethane, or other various hydrocarbon compounds.

[0023] In some embodiments, the mechanical reactor moves in a rolling, vibrating, or planetary ball mill manner.

[0024] In some embodiments, the amount of catalyst filled in the mechanical reactor is 1 / 10 to 1 / 2 of the reactor volume.

[0025] Mechanochemistry utilizes grinding media to introduce mechanical energy into chemical reaction processes. Through the interaction between the grinding media and the reactor wall, such as compression, collision, and friction, mechanical forces are generated, initiating or promoting the breaking of chemical bonds in reactants and the formation of products. Simultaneously, it effectively eliminates the negative effects of mass transfer and diffusion on the chemical reaction. Combining the characteristics of alkane cracking reactions, loading active metal elements onto the surface of metal spheres to form an alloy structure not only effectively improves the catalyst's resistance to sintering, but also, because this zero-dimensional catalyst lacks a porous structure, carbon deposits generated at reaction sites on the catalyst surface under dynamic reaction conditions can be promptly removed by mechanical force, thus achieving both sintering and carbon deposition resistance.

[0026] In addition, studies have shown that the introduction of mechanical energy effectively reduces the temperature and pressure required for catalytic reactions. Therefore, applying mechanical catalytic reaction methods to alkane cracking reactions can effectively reduce the active temperature window of the catalytic reaction, realizing a reaction process that can crack hydrocarbons to produce hydrogen and carbon powder with a long lifespan.

[0027] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:

[0028] This invention introduces mechanical energy into the cracking reaction of hydrocarbon compounds. Under the dynamic reaction conditions of mechanical catalysis, the mechanical force generated by the mutual movement of the metal ball and the inner wall of the reactor effectively strips off the solid carbon generated on the catalyst surface, thereby greatly extending the service life of the catalyst.

[0029] This invention directly deposits active metal elements onto the surface of a metal sphere to form an alloy structure, which effectively improves the thermal stability and anti-sintering ability of the catalyst. At the same time, the reactive centers of this zero-dimensional catalyst are fully exposed in the reaction atmosphere, resulting in high catalytic efficiency.

[0030] The mechanical catalytic hydrocarbon cracking process described in this invention can improve hydrogen production efficiency and effectively eliminate the limitation of catalyst reaction lifetime imposed by solid carbon. Using alloy spheres as the reaction catalyst significantly improves the utilization rate and stability of the active metal, and the catalyst exhibits good cycle performance, remaining activated for over 300 hours of continuous catalytic cracking without deactivation, and the reaction process produces no direct carbon emissions. Attached Figure Description

[0031] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0032] Figure 1 This is the Raman spectrum of the carbon black by-product in an embodiment of the present invention. Detailed Implementation

[0033] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0034] The present invention will be further described below with reference to the embodiments.

[0035] Example 1

[0036] 300g of iron balls with a diameter of 9mm were ultrasonically treated in DMF for 1h, washed three times each with ethanol and deionized water, and dried to obtain clean iron balls. The iron balls were then submerged in 250mL of perrhenic acid aqueous solution (0.001M), ultrasonically treated for 1h, and dried to obtain Re-Fe balls. The Re-Fe balls were calcined in a muffle furnace at 200℃ for 0.5h, and then treated in a tube furnace under hydrogen purging at 300℃ for 0.5h to obtain a Re / Fe catalyst with a Re loading of 0.0000007wt%.

[0037] The Re / Fe catalyst was loaded into a 250 mL vibrating mechanical reactor. The motor drove the reactor to perform a periodic reciprocating motion, which caused the catalyst to collide with Re / Fe and generate mechanical energy. The reaction was carried out for 150 h with 50 mL / min of methane reaction gas, at a vibration frequency of 500 rpm and a temperature of 100 °C. The reaction pressure was 0.1 MPa, the methane conversion rate was 5%, and the hydrogen selectivity was >99%.

[0038] Example 2

[0039] 300g of iron balls with a diameter of 5mm were ultrasonically treated in DMF for 1h, washed three times each with ethanol and deionized water, and dried to obtain clean iron balls. The iron balls were then submerged in 250mL of perrhenic acid aqueous solution (1.5M), ultrasonically treated for 1h, and dried to obtain Re-Fe balls. The Re-Fe balls were calcined in a muffle furnace at 500℃ for 4h, and then treated in a tube furnace under hydrogen purging at 1000℃ for 2h to obtain a Re / Fe catalyst with a Re loading of 0.008wt%.

[0040] The Re / Fe catalyst was loaded into a 250 mL rolling mechanical reactor. The motor drove the reactor to rotate around the central axis, which in turn caused the Re / Fe balls to collide and generate mechanical energy. The reaction was carried out for 150 h with 20 mL / min of methane reaction gas, under the reaction conditions of 1000 rpm vibration frequency and 300 °C. The reaction pressure was 0.1 MPa, the methane conversion rate was 25%, and the hydrogen selectivity was >99%.

[0041] Example 3

[0042] 300g of cobalt spheres with a diameter of 6mm were ultrasonically treated in DMF for 1h, washed three times each with ethanol and deionized water, and dried to obtain clean cobalt spheres. The cobalt spheres were then submerged in 250mL of 0.01M bismuth acetate aqueous solution, ultrasonically treated for 1h, and dried to obtain Bi-Co spheres. The Bi-Co spheres were calcined in a muffle furnace at 400℃ for 1h, and then treated in a tube furnace under hydrogen purging at 750℃ for 3h to obtain a Bi / Co catalyst with a Bi loading of 0.00009wt%.

[0043] The Bi / Co catalyst was loaded into a 250mL planetary mechanical reactor. The motor drove the reactor to rotate in a planetary motion, which in turn caused the Bi / Co balls to collide and generate mechanical energy. Ethane reaction gas was introduced at a rate of 100mL / min. The reaction was carried out at a vibration frequency of 1500rpm and a temperature of 500℃ for 150h. The reaction pressure was 0.3MPa. The ethane conversion rate was 35%, and the hydrogen selectivity was >99%.

[0044] Example 4

[0045] 300g of vanadium-chromium spheres with a diameter of 4mm were ultrasonically treated in DMF for 1h, washed three times each with ethanol and deionized water, and dried to obtain clean vanadium-chromium spheres. The vanadium-chromium spheres were submerged in 250mL of potassium molybdate aqueous solution (0.01M) and manganese carbonate aqueous solution (0.1M), ultrasonically treated for 1h, and dried to obtain MoMn-VCr spheres. The MoMn-VCr spheres were calcined in a muffle furnace at 450℃ for 3h, and then treated in a tube furnace under hydrogen purging at 950℃ for 1h to obtain the MoMn / VCr catalyst with a Mo loading of 0.007wt% and a Mn loading of 0.029wt%.

[0046] The MoMn / VCr catalyst was loaded into a 250mL rotary drum reactor. The reactor was rotated by a motor, which caused the MoMn / VCr balls to collide and generate mechanical energy. The reaction was carried out for 150 hours with 200mL / min propane reaction gas, under the reaction conditions of 600rpm vibration frequency and 400℃, and the reaction pressure was 0.1MPa. The propane conversion rate was 30%, and the hydrogen selectivity was >99%.

[0047] Example 5

[0048] 300g of nickel-molybdenum spheres with a diameter of 8mm were ultrasonically treated in DMF for 1h, washed three times each with ethanol and deionized water, and dried to obtain clean nickel-molybdenum spheres. The nickel-molybdenum spheres were submerged in 250mL of a 0.1M sodium tungstate and 0.6M potassium dichromate aqueous solution, ultrasonically treated for 1h, and dried to obtain WCr-NiMo spheres. The WCr-NiMo spheres were calcined in a muffle furnace at 350℃ for 2h, and then treated in a tube furnace under hydrogen purging at 650℃ for 4h to obtain the WCr / NiMo catalyst, with W and Cr loadings of 0.007wt% and 1.5wt%, respectively.

[0049] The WCr / NiMo catalyst was loaded into a 250mL rotary drum reactor. The motor drove the reactor to rotate around its central axis, which in turn caused the WCr / NiMo balls to collide and generate mechanical energy. The reactor was filled with 100mL / min of methane reaction gas and reacted for 150h under the following conditions: vibration frequency 2500rpm and temperature 250℃. The reaction pressure was 0.3MPa, the methane conversion rate was 20%, and the hydrogen selectivity was >99%.

[0050] Example 6

[0051] 300g of iron-manganese spheres with a diameter of 9mm were ultrasonically treated in DMF for 1h, washed three times each with ethanol and deionized water, and dried to obtain clean iron-ruthenium spheres. The iron-ruthenium spheres were submerged in 250mL of a 0.001M rhodium chloride and 0.3M chloroiridium acid aqueous solution, ultrasonically treated for 1h, and dried to obtain RhIr-FeMn spheres. The RhIr-FeMn spheres were calcined in a muffle furnace at 200℃ for 1h, and then treated in a tube furnace under hydrogen purging at 550℃ for 4h to obtain the RhIr / FeMn catalyst, with Rh and Ir loadings of 0.00001wt% and 2wt%, respectively.

[0052] The RhIr / FeMn catalyst was loaded into a 250 mL vibrating mechanical reactor. The motor drove the reactor to reciprocate left and right, which in turn caused the RhIr / FeMn spheres to collide and generate mechanical energy. Methane reaction gas was introduced at a rate of 50 mL / min. The reaction was carried out at a vibration frequency of 2500 rpm and a temperature of 450 °C for 150 h. The reaction pressure was 0.5 MPa. The methane conversion rate was 30%, and the hydrogen selectivity was >99%.

[0053] Example 7

[0054] 300g of iron-bismuth spheres with a diameter of 9mm were ultrasonically treated in DMF for 1h, washed three times each with ethanol and deionized water, and dried to obtain clean iron-ruthenium spheres. The iron-bismuth spheres were submerged in 250mL of 0.9M rhenium pentacarbonyl chloride ethanol solution, ultrasonically treated for 1h, and dried to obtain Re-FeBi spheres. The Re-FeBi spheres were calcined in a muffle furnace at 200℃ for 1h, and then treated in a tube furnace under hydrogen purging at 550℃ for 4h to obtain the Re / FeBi catalyst with a Re loading of 3wt%.

[0055] The Re / FeBi catalyst was loaded into a 250 mL vibrating mechanical reactor. The motor drove the reactor to reciprocate left and right, which in turn caused the Re / FeBi balls to collide and generate mechanical energy. Methane reaction gas was introduced at a rate of 30 mL / min. The reaction was carried out at a vibration frequency of 2000 rpm and a temperature of 250 °C for 150 h. The reaction pressure was 5 MPa. The methane conversion rate was 40%, and the hydrogen selectivity was >99%.

[0056] Example 8

[0057] 300g of vanadium cobalt zinc spheres with a diameter of 9mm were ultrasonically treated in DMF for 1h, washed three times each with ethanol and deionized water, and dried to obtain clean vanadium cobalt zinc spheres. The vanadium cobalt zinc spheres were submerged in 250mL of rhenium pentacarbonyl chloride (0.5M) ethanol solution, ultrasonically treated for 1h, and dried to obtain Re-VCoZn spheres. The Re-VCoZn spheres were calcined in a muffle furnace at 400℃ for 1h, and then treated in a tube furnace under hydrogen purging at 750℃ for 2h to obtain the Re-VCoZn catalyst with a Re loading of 0.08wt%.

[0058] The Re-VCoZn catalyst was loaded into a 250 mL vibrating mechanical reactor. The motor drove the reactor to reciprocate left and right, which in turn caused the Re-VCoZn balls to collide and generate mechanical energy. Methane containing pentadecane, propylene, and ethylene at a flow rate of 30 mL / min was used as the reaction gas through a bubbler. The reaction was carried out for 150 h under the conditions of a vibration frequency of 1000 rpm and a temperature of 450 °C. The reaction pressure was 2 MPa. The conversion rates of methane, pentadecane, propylene, and ethylene were 25%, 80%, 30%, and 60%, respectively, and the hydrogen selectivity was >99%.

[0059] The above Examples 1-8 of this invention were used to conduct activity tests on the production of hydrogen and carbon black from hydrocarbon cracking. The solid carbon powder was detected as carbon black by Raman spectroscopy. The corresponding test results are shown in Table 1 below. Figure 1 As shown:

[0060] Table 1 Activity evaluation of each catalyst

[0061]

[0062]

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. The application of ReVCoZn alloy catalyst in mechanocatalytic hydrocarbon cracking for hydrogen production and carbon black, characterized by: It includes a vanadium-cobalt-zinc metal sphere carrier and an active metal layer loaded on the surface of the metal sphere carrier, wherein the active metal is Re, and the loading of Re is 0.008%-3.2wt%; The preparation method of ReVCoZn alloy catalyst is as follows: Clean metal spheres are immersed in an active metal precursor solution, ultrasonically treated for a set time, and then dried to obtain ReVCoZn spheres. The ReVCoZn spheres were calcined in a muffle furnace at 400°C for 1 hour, and then treated in a tube furnace at 750°C for 2 hours under hydrogen purging to obtain the ReVCoZn catalyst. The ReVCoZn catalyst was loaded into a vibrating mechanical reactor. The motor drove the reactor to reciprocate left and right, which in turn caused the ReVCoZn balls to collide and generate mechanical energy. Methane containing pentadecane, propylene, and ethylene was used as the reaction gas through a bubbler. The reaction was carried out for 150 hours under the reaction conditions of 1000 rpm vibration frequency and 450℃, and the reaction pressure was 2 MPa.

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