A catalyst for coal pyrolysis to produce carbon monoxide and hydrogen and a method for preparing the same
By composite rare earth elements on the surface of iron oxide and loading them onto nitrogen-doped graphene oxide, the problems of insufficient activity and easy carbon deposition of traditional iron-based catalysts are solved, thereby improving the activity and stability of the catalyst, increasing the generation efficiency of CO and H2, and reducing catalyst loss.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI JINENG CHEM CO LTD
- Filing Date
- 2025-10-28
- Publication Date
- 2026-07-21
AI Technical Summary
Traditional iron-based catalysts suffer from problems such as insufficient activity and selectivity, easy sintering and carbon deposition deactivation in the process of producing carbon monoxide and hydrogen from coal pyrolysis. The uniform distribution and interaction of rare earth elements and iron-based components have not been fully utilized.
Rare earth elements were composited on the surface of iron oxide (Fe3O4), and rare earth oxides were formed on the surface of iron oxide through urea hydrolysis co-precipitation. The iron oxide-rare earth composite was then loaded onto nitrogen-doped graphene oxide. Combined with high-temperature calcination and hydrothermal reaction, a catalyst with good electronic interaction was formed.
It significantly improved the activity and stability of the catalyst, increased the yield of CO and H2, reduced the carbon deposition rate, reduced catalyst loss, and achieved rapid magnetic separation and efficient adsorption and activation of reactant molecules.
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Figure CN121372427B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst materials technology, and relates to a catalyst for producing carbon monoxide and hydrogen through coal pyrolysis and its preparation method. Background Technology
[0002] Coal, as the world's most abundant fossil fuel, plays a vital role in ensuring energy security and achieving sustainable development through its clean and efficient utilization. Coal pyrolysis to produce carbon monoxide and hydrogen is one of the core technologies in the coal chemical industry, providing key raw materials for downstream processes such as Fischer-Tropsch synthesis and methanol synthesis. In this technology, catalysts play a crucial role in lowering the activation energy of the reaction, increasing the reaction rate, and directionally controlling the distribution of products.
[0003] Currently, catalysts used for coal pyrolysis and gasification mainly include metal-based catalysts and carbon-based catalysts. Among them, iron-based catalysts have attracted widespread attention due to their abundant resources, low cost, and certain catalytic activity. However, traditional iron-based catalysts suffer from significant technical bottlenecks in application, such as insufficient activity and selectivity, easy sintering, and carbon deposition deactivation.
[0004] Rare earth elements, due to their unique electronic structure, possess excellent oxygen storage and release capabilities and electronic modulation effects, which theoretically can enhance the redox performance of catalysts and inhibit carbon deposition. However, current technologies mostly employ simple physical mixing or conventional impregnation methods to combine rare earth elements with iron-based components. This approach makes it difficult to achieve uniform distribution and strong interactions of active components at the atomic and nanoscale, thus failing to fully realize the promoting effect of rare earth elements.
[0005] Therefore, there is an urgent need to develop a catalyst and preparation method for producing carbon monoxide and hydrogen from coal pyrolysis. Summary of the Invention
[0006] The purpose of this invention is to provide a catalyst for producing carbon monoxide and hydrogen from coal pyrolysis and its preparation method, which has good catalytic activity and stability.
[0007] The objective of this invention can be achieved through the following technical solutions:
[0008] A catalyst for coal pyrolysis to produce carbon monoxide and hydrogen, the catalyst formulation comprising the following components, by weight percentage: 8%–18% active component, 8%–15% dispersant, and the balance being thermal oil.
[0009] The active component is prepared by compounding rare earth elements on the surface of iron oxide (Fe3O4) and then loading the iron oxide-rare earth composite onto nitrogen-doped graphene oxide.
[0010] As a preferred embodiment of the present invention, the method for preparing the active component is as follows:
[0011] S2-1: Disperse ferric oxide in deionized water, sonicate for 10-30 min, add rare earth salt solution dropwise at 60-80 ℃ with stirring, sonicate for 10-30 min, then add urea solution dropwise, maintain temperature and continue stirring for 2-3 h, wash with deionized water, and then calcine at 300-500 ℃ for 30-60 min to obtain powder A;
[0012] S2-2: Add graphene oxide powder to deionized water, sonicate for 10-30 min, add nitrogen source to graphene oxide dispersion, and continue sonication for 30-60 min to obtain solution B;
[0013] S2-3: Add powder A to solution B, wherein the mass ratio of powder A to graphene oxide is (0.5~2):1, sonicate for 30~60 min, transfer the mixture to a hydrothermal reactor, and react at 160~180 ℃ for 8~12 h to obtain the active component.
[0014] As a preferred embodiment of the present invention, the rare earth salt in S2-1 includes, but is not limited to, one or both of cerium nitrate and lanthanum nitrate.
[0015] As a preferred embodiment of the present invention, the molar ratio of rare earth elements to iron elements in S2-1 is (0.1~0.3):1.
[0016] As a preferred embodiment of the present invention, the molar ratio of urea to rare earth elements in S2-1 is (5~15):1.
[0017] As a preferred embodiment of the present invention, the nitrogen source in S2-2 is one or both of urea or melamine.
[0018] As a preferred embodiment of the present invention, the mass ratio of nitrogen source to graphene oxide in S2-2 is (0.3~0.5):1.
[0019] In a preferred embodiment of the present invention, the heat transfer oil is industrial white oil.
[0020] As a preferred embodiment of the present invention, the dispersant includes, but is not limited to, one or both of high-alkali calcium petroleum sulfonate and polyisobutylene diimide.
[0021] A method for preparing a catalyst for coal pyrolysis to produce carbon monoxide and hydrogen, the specific steps of which are as follows:
[0022] The heat transfer oil and active components are added to a water bath and heated to 50-70°C under stirring. Then, a dispersant is added, heating is stopped, and stirring is continued for 10-30 minutes. The mixture is then ground in an oil bath for 30-60 minutes using an ultrafine powder grinder to obtain the catalyst for producing carbon monoxide and hydrogen from coal pyrolysis.
[0023] During coal pyrolysis, iron(III) oxide (Fe3O4) forms a strong chemisorption with CO molecules through its unsaturated coordination sites on its surface, and with the help of Fe... 2+ / Fe 3+ The redox cycle promotes the activation and breakage of CO bonds, generating surface carbon species and reactive oxygen species. Simultaneously, the intrinsic oxygen vacancies in the iron oxide lattice can act as activation centers for CH bonds, inducing selective cracking of low-carbon hydrocarbon molecules such as methane to generate H2 and inhibiting deep carbon deposition, thereby significantly improving the initial syngas generation efficiency. Furthermore, the inherent ferromagnetism of iron oxide endows the catalyst with excellent magnetic response properties, enabling rapid separation via an external magnetic field after the reaction, significantly reducing catalyst loss and recovery costs in industrial processes.
[0024] Rare earth salts form uniform rare earth oxides on the surface of magnetite (Fe3O4) through a co-precipitation method assisted by urea hydrolysis combined with high-temperature calcination. Among these, cerium oxide contains Ce... 3+ / Ce 4+ The reversible valence-changing properties of lanthanum oxide effectively modulate the local electronic environment of Fe ions through interfacial electron transfer, increasing the concentration of oxygen vacancies on the surface. These oxygen vacancies serve as key activation sites for water molecules and CO2, significantly lowering the energy barrier of the reaction and promoting H2 generation and CO conversion. Simultaneously, rare earth oxides cover surface defect sites of Fe3O4 through steric hindrance, inhibiting the carbon deposition rate by more than 60%. Furthermore, the rare earth layer covers the high-energy crystal faces of Fe3O4 through spatial isolation, effectively blocking the deposition of carbon precursors and reducing the carbon deposition rate by more than 60%. The reaction of lanthanum oxide with sulfides in coal significantly reduces the adsorption of sulfur at active sites, ensuring that the catalyst maintains more than 90% of its initial activity in sulfur-containing coal coke. In addition, rare earth oxides act as a thermal stability barrier, effectively preventing direct contact between Fe3O4 particles at high temperatures, inhibiting particle migration and sintering, and giving the catalyst good stability.
[0025] Nitrogen source promotes in-situ doping of nitrogen atoms into the graphene lattice via a hydrothermal reaction, forming nitrogen-doped graphene. Nitrogen doping introduces defect sites such as pyridine nitrogen and graphitic nitrogen on the graphene surface. These defect sites form coordination bonds with the π orbitals of CO through lone pairs of electrons, significantly reducing the CO dissociation energy barrier. Simultaneously, the lone pairs of nitrogen act as strong anchoring sites, interacting electronically with the iron(III) oxide-rare earth composite, increasing the electron density of the active center and thus enhancing the adsorption and activation capacity of reactant molecules. The two-dimensional sheet structure of nitrogen-doped graphene provides a rapid diffusion channel for reactants and products, significantly reducing mass transfer resistance. Furthermore, the graphene framework possesses excellent electronic conductivity; nitrogen doping further modulates the electron cloud distribution of graphene, optimizing charge transfer between the iron(III) oxide-rare earth composite and the support, resulting in a significant improvement in the overall catalyst activity.
[0026] The beneficial effects of this invention are:
[0027] In this invention, the active component, iron(III) oxide, efficiently promotes CO dissociation and methane cracking through adsorption and catalysis, significantly increasing CO and H2 yields. Its ferromagnetism enables rapid magnetic separation, reducing catalyst consumption costs. Rare earth salts, through co-precipitation combined with high-temperature calcination, form a rare earth oxide layer on the surface of iron(III) oxide. This increases oxygen vacancy concentration, enhancing the activation of H2O and CO2, while simultaneously covering surface defects to inhibit carbon deposition. It also binds to sulfur, reducing its adsorption at active sites and acting as a barrier to prevent particle migration and aggregation, maintaining a high specific surface area and activity. Nitrogen source doping transforms graphene into nitrogen-doped graphene with pyridine nitrogen and graphitic nitrogen defect sites, lowering the CO dissociation energy barrier. Its lone pair electrons interact with the iron(III) oxide-rare earth complex, optimizing the electron density of the active centers. Furthermore, the two-dimensional sheet structure facilitates material diffusion, collectively enhancing the catalyst's adsorption and activation capacity for reactant molecules and its overall activity. Attached Figure Description
[0028] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.
[0029] Figure 1 The image shows the TGMS spectrum of the catalyst prepared in Example 1 of this invention. Detailed Implementation
[0030] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.
[0031] Example 1
[0032] A catalyst for coal pyrolysis to produce carbon monoxide and hydrogen, the catalyst formulation comprising, by weight percentage, 13% active component, 12% polyisobutylene diimide, and the balance industrial white oil.
[0033] The active component is prepared by compounding rare earth elements on the surface of iron oxide (Fe3O4) and then loading the iron oxide-rare earth composite onto nitrogen-doped graphene oxide.
[0034] The preparation method of the active component is as follows:
[0035] S2-1: Disperse iron(III) oxide in deionized water and sonicate for 20 min. Add lanthanum nitrate solution dropwise at 70 °C with stirring, wherein the molar ratio of lanthanum to iron is 0.2:1. Sonicate for 20 min, then add urea solution dropwise, wherein the molar ratio of urea to lanthanum is 10:1. Maintain the temperature and continue stirring for 2.5 h. Wash with deionized water and then calcine at 400 °C for 45 min to obtain powder A.
[0036] S2-2: Add graphene oxide powder to deionized water and sonicate for 20 min. Add urea to the graphene oxide dispersion. The mass ratio of urea to graphene oxide is 0.4:1. Continue sonicating for 45 min to obtain solution B.
[0037] S2-3: Add powder A to solution B, wherein the mass ratio of powder A to graphene oxide is 1.2:1, sonicate for 45 min, transfer the mixture to a hydrothermal reactor, and react at 170 °C for 10 h to obtain the active component.
[0038] A method for preparing a catalyst for coal pyrolysis to produce carbon monoxide and hydrogen, the specific steps of which are as follows:
[0039] Industrial white oil and active components were added to a water bath and heated to 60 °C under stirring. Then, a dispersant was added, heating was stopped, and stirring was continued for 20 min. The mixture was then oil bath milled for 45 min to obtain the catalyst for coal cracking to produce carbon monoxide and hydrogen.
[0040] Example 2
[0041] A catalyst for coal pyrolysis to produce carbon monoxide and hydrogen, the catalyst formulation comprising the following components, by weight percentage: 8% active component, 8% high-alkali calcium petroleum sulfonate, and the balance industrial white oil.
[0042] The active component is prepared by compounding rare earth elements on the surface of iron oxide (Fe3O4) and then loading the iron oxide-rare earth composite onto nitrogen-doped graphene oxide.
[0043] The preparation method of the active component is as follows:
[0044] S2-1: Disperse iron(III) oxide in deionized water and sonicate for 10 min. Add cerium nitrate solution dropwise at 60 °C with stirring, wherein the molar ratio of cerium to iron is 0.1:1. Sonicate for 10 min, then add urea solution dropwise, wherein the molar ratio of urea to cerium is 5:1. Maintain the temperature and continue stirring for 2 h. Wash with deionized water and then calcine at 300 °C for 30 min to obtain powder A.
[0045] S2-2: Add graphene oxide powder to deionized water and sonicate for 10 min. Add melamine to the graphene oxide dispersion. The mass ratio of melamine to graphene oxide is 0.3:1. Continue sonicating for 30 min to obtain solution B.
[0046] S2-3: Add powder A to solution B, wherein the mass ratio of powder A to graphene oxide is 0.5:1, sonicate for 30 min, transfer the mixture to a hydrothermal reactor, and react at 160 °C for 8 h to obtain the active component.
[0047] A method for preparing a catalyst for coal pyrolysis to produce carbon monoxide and hydrogen, the specific steps of which are as follows:
[0048] Industrial white oil and active components were added to a water bath and heated to 50°C under stirring. Then, high-alkali calcium petroleum sulfonate was added, heating was stopped, and stirring was continued for 10 minutes. The mixture was then ground in an oil bath for 30 minutes using an ultrafine powder grinder to obtain the catalyst for producing carbon monoxide and hydrogen from coal pyrolysis.
[0049] Example 3
[0050] A catalyst for coal cracking to produce carbon monoxide and hydrogen, the catalyst formulation comprising, by weight percentage, 18% active component, 15% polyisobutylene diimide, and the balance industrial white oil.
[0051] The active component is prepared by compounding rare earth elements on the surface of iron oxide (Fe3O4) and then loading the iron oxide-rare earth composite onto nitrogen-doped graphene oxide.
[0052] The preparation method of the active component is as follows:
[0053] S2-1: Disperse iron(III) oxide in deionized water and sonicate for 30 min. Add lanthanum nitrate solution dropwise at 80 °C with stirring, wherein the molar ratio of lanthanum to iron is 0.3:1. Sonicate for 30 min, then add urea solution dropwise, wherein the molar ratio of urea to rare earth elements is 15:1. Maintain the temperature and continue stirring for 3 h. Wash with deionized water and then calcine at 500 °C for 60 min to obtain powder A.
[0054] S2-2: Add graphene oxide powder to deionized water and sonicate for 30 min. Add urea to the graphene oxide dispersion. The mass ratio of urea to graphene oxide is 0.5:1. Continue sonicating for 60 min to obtain solution B.
[0055] S2-3: Add powder A to solution B, wherein the mass ratio of powder A to graphene oxide is 2:1, sonicate for 60 min, transfer the mixture to a hydrothermal reactor, and react at 180 ℃ for 12 h to obtain the active component.
[0056] A method for preparing a catalyst for coal pyrolysis to produce carbon monoxide and hydrogen, the specific steps of which are as follows:
[0057] Industrial white oil and active components were added to a water bath and heated to 70°C under stirring. Polyisobutylene diimide was then added, heating was stopped, and stirring was continued for 30 minutes. The mixture was then oil bath milled for 60 minutes to obtain the catalyst for coal cracking to produce carbon monoxide and hydrogen.
[0058] Comparative Example 1
[0059] The preparation of the active component does not involve the addition of iron tetroxide, and the remaining steps are the same as in Example 1.
[0060] Comparative Example 2
[0061] Rare earth salt solution is not added in the preparation of the active component, and the remaining steps are the same as in Example 1.
[0062] Comparative Example 3
[0063] In the preparation of the active component S2-2, no nitrogen source is added, and the remaining steps are the same as in Example 1.
[0064] Comparative Example 4
[0065] In the preparation of the active component S2-1, only the iron tetroxide and rare earth salt are physically stirred and mixed; the remaining steps are the same as in Example 1.
[0066] Performance testing
[0067] The hydrogen and carbon monoxide contents were determined using a TG8000-SP3FTIR-GCMS2400. The sample consisted of raw coal and catalyst prepared at a mass ratio of 1000:1. The specific results are recorded in the table below.
[0068] Hydrogen content (%) Carbon monoxide content (%) Example 1 0.88 6.16 Example 2 0.75 5.83 Example 3 0.93 6.54 Comparative Example 1 0.33 3.41 Comparative Example 2 0.42 4.37 Comparative Example 3 0.30 3.92 Comparative Example 4 0.49 5.24
[0069] As can be seen from the examples and comparative data, the catalyst prepared by the present invention has good catalytic activity.
[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. A catalyst for coal pyrolysis to produce carbon monoxide and hydrogen, characterized in that, The catalyst formulation comprises the following components, by weight percentage: 8%–18% active component, 8%–15% dispersant, and the balance being heat transfer oil. The active component is prepared by compounding rare earth elements on the surface of iron oxide and then loading the iron oxide-rare earth composite onto nitrogen-doped graphene oxide.
2. The catalyst for coal pyrolysis to produce carbon monoxide and hydrogen according to claim 1, characterized in that, The preparation method of the active component is as follows: S2-1: Disperse ferric oxide in deionized water, sonicate for 10-30 min, add rare earth salt solution dropwise at 60-80 ℃ with stirring, sonicate for 10-30 min, then add urea solution dropwise, maintain temperature and continue stirring for 2-3 h, wash with deionized water, and then calcine at 300-500 ℃ for 30-60 min to obtain powder A; S2-2: Add graphene oxide powder to deionized water, sonicate for 10-30 min, add nitrogen source to graphene oxide dispersion, and continue sonication for 30-60 min to obtain solution B; S2-3: Add powder A to solution B, wherein the mass ratio of powder A to graphene oxide is (0.5~2):1, sonicate for 30~60 min, transfer the mixture to a hydrothermal reactor, and react at 160~180 ℃ for 8~12 h to obtain the active component.
3. The catalyst for coal pyrolysis to produce carbon monoxide and hydrogen according to claim 2, characterized in that, The rare earth salt in S2-1 includes one or both of cerium nitrate and lanthanum nitrate.
4. The catalyst for coal pyrolysis to produce carbon monoxide and hydrogen according to claim 2, characterized in that, The molar ratio of rare earth elements to iron in S2-1 is (0.1~0.3):
1.
5. A catalyst for coal pyrolysis to produce carbon monoxide and hydrogen according to claim 2, characterized in that, The molar ratio of urea to rare earth elements in S2-1 is (5~15):
1.
6. The catalyst for coal pyrolysis to produce carbon monoxide and hydrogen according to claim 2, characterized in that, The nitrogen source in S2-2 is one or both of urea or melamine.
7. The catalyst for coal pyrolysis to produce carbon monoxide and hydrogen according to claim 2, characterized in that, The mass ratio of nitrogen source to graphene oxide in S2-2 is (0.3~0.5):
1.
8. The catalyst for coal pyrolysis to produce carbon monoxide and hydrogen according to claim 1, characterized in that, The heat transfer oil is industrial white oil.
9. A catalyst for coal pyrolysis to produce carbon monoxide and hydrogen according to claim 1, characterized in that, The dispersant includes one or both of high-alkali calcium petroleum sulfonate and polyisobutylene diimide.
10. A method for preparing a catalyst for coal pyrolysis to produce carbon monoxide and hydrogen as described in any one of claims 1 to 9, characterized in that, The specific steps of the preparation method are as follows: The heat transfer oil and active components are added to a water bath and heated to 50-70°C under stirring. Then, a dispersant is added, heating is stopped, and stirring is continued for 10-30 minutes. The mixture is then ground in an oil bath for 30-60 minutes using an ultrafine powder grinder to obtain the catalyst for producing carbon monoxide and hydrogen from coal pyrolysis.