Coal liquefaction catalyst based on polyvalent complex iron salt and coal liquefaction method

Abstract

This invention discloses a coal liquefaction catalyst based on multivalent iron salts and a coal liquefaction method, relating to the field of coal liquefaction technology. The coal liquefaction catalyst comprises a first active component and a second active component; the first active component is a multivalent iron salt solution containing ferrous and ferric ions; the second active component is a solution containing one or more highly active metal salts selected from cobalt, molybdenum, nickel, and tungsten ions. In the coal liquefaction method using this catalyst, the first and second active components are directly loaded onto pulverized coal, utilizing the coal itself as a dispersion medium. This allows the active components to generate a highly dispersed active phase in situ during the reaction heating stage and under hydrogenation sulfidation conditions, and to maintain close contact with the reactants, significantly improving catalytic efficiency. This approach skips the multiple steps required for traditional solid catalyst preparation, such as precipitation, filtration, drying, and calcination, significantly simplifying the catalyst preparation process and reducing production costs.

Description

Technical Field

[0001] This invention belongs to the field of coal liquefaction technology, specifically relating to a coal liquefaction catalyst based on multivalent complex iron salts and a coal liquefaction method. Background Technology

[0002] Direct coal liquefaction (DCL) is a clean coal technology that converts solid coal into liquid fuel under high temperature, high pressure, and the presence of a catalyst. It is one of the important ways to achieve the clean and efficient utilization of coal. The catalyst is the core element of DCL, and its performance directly affects the coal conversion rate, oil yield, and the economics of the process.

[0003] Iron-based catalysts have become a major focus of research and industrial application in coal direct liquefaction due to their advantages such as abundant resources, low cost, environmental friendliness, and single-use without the need for recycling. Existing iron-based catalysts are typically used in the form of solid precursors or pretreated supported substrates. Their forms include FeOOH-based catalysts (α, β, γ-FeOOH), iron oxides (Fe2O3, Fe3O4), oil-soluble iron, iron sulfides, and various derivative phases (FeS2, Fe...) derived from iron-based precursors through heat treatment or presulfurization. 1-x S), etc.

[0004] Existing iron-based catalysts still have the following problems: 1. Complex catalyst preparation process: Existing iron-based catalysts all require multiple processes such as precipitation, oxidation, filtration, drying, calcination, and pulverization to be prepared into solid catalysts before they can be used in coal liquefaction reactions. The production process is complex, energy consumption is high, and production costs are increased, which is not conducive to the economics of industrial application.

[0005] 2. The dispersion of active components is still limited: the dispersion of solid catalyst particles in the coal liquefaction system is still difficult to achieve an ideal state. The contact efficiency between the active components of the catalyst and the organic matter in the coal is limited, and some active sites cannot be fully utilized, which affects the further improvement of catalytic efficiency.

[0006] Therefore, developing a coal liquefaction catalyst with simple process, low cost, and highly dispersed active components, as well as its application method, is of great significance for promoting the advancement of direct coal liquefaction technology. Summary of the Invention

[0007] In view of this, the object of the present invention is to provide a coal liquefaction catalyst based on multivalent state composite iron salt that is simple to process, low in cost and has highly dispersed active components, as well as a coal liquefaction method using the catalyst.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A first aspect of the present invention is to provide a coal liquefaction catalyst based on a multivalent complex iron salt, comprising a first active component and a second active component; The first active component is a multivalent iron salt solution containing ferrous and ferric ions; The second active component is a solution of highly active metal salts containing one or more of cobalt ions, molybdenum ions, nickel ions, and tungsten ions.

[0009] In a specific embodiment, the first active component is an aqueous solution prepared using water-soluble ferrous salt and ferric salt; or, the first active component is an aqueous solution prepared using water-soluble ferrous salt and oxidized in air, so that a portion of the ferrous ions are oxidized to ferric ions.

[0010] In the specific embodiment, the ferrous salt is at least one of ferrous sulfate, ferrous nitrate, or ferrous chloride, and the ferric salt is at least one of ferric sulfate, ferric nitrate, or ferric chloride.

[0011] In the specific scheme, the total concentration of ferrous ions and ferric ions in the first active component is 0.01 mol / L to 3.0 mol / L.

[0012] In the specific scheme, the molar ratio of ferrous ions to ferric ions in the first active component is (1~10):(10~1).

[0013] In the specific scheme, the second active component is a highly active metal salt aqueous solution prepared by one or more of water-soluble cobalt salt, molybdenum salt, nickel salt and tungsten salt; wherein the cobalt salt is cobalt chloride or cobalt nitrate; the molybdenum salt is ammonium heptamolybdate or ammonium molybdate; the nickel salt is nickel sulfate or nickel nitrate; and the tungsten salt is sodium tungstate or calcium tungstate.

[0014] In the specific scheme, the total concentration of cobalt ions, molybdenum ions, nickel ions and tungsten ions in the second active component is 0.01 mol / L to 3.0 mol / L.

[0015] A second aspect of the present invention is to provide a coal liquefaction method using the coal liquefaction catalyst described above, the coal liquefaction method comprising the following steps: S10. Prepare the first active component and the second active component respectively; S20. The first active component and the second active component are loaded onto coal powder individually or in combination by impregnation or spraying to obtain coal powder loaded with catalyst. S30. The coal powder with the supported catalyst is mixed with solvent oil to prepare an oil-coal slurry; S40. In the presence of hydrogen, the oil-coal slurry is subjected to a hydrogenation liquefaction reaction, so that the first active component and the second active component loaded on the coal powder generate a catalytic active phase in situ during the reaction, thereby catalyzing the co-liquefaction of coal and oil.

[0016] In the specific scheme, in step S20, the mass ratio of the first active component to the coal powder is (0.01~4):100 based on the mass of iron; and the molar ratio of the second active component to the iron in the first active component is (0.01~1):100 based on the total molar amount of cobalt, molybdenum, nickel and tungsten.

[0017] In the specific scheme, the hydrogenation liquefaction reaction is carried out in the presence of sulfur, which is added in the form of elemental sulfur or sulfur-containing compounds.

[0018] The coal liquefaction catalyst and method based on multivalent iron salts provided in this invention directly load multivalent iron salt solutions and highly active metal salt solutions onto pulverized coal, utilizing the coal itself as a dispersion medium. This allows the active components to form a highly dispersed active phase in situ during the reaction heating stage and under hydrogenation sulfidation conditions, thus maintaining close contact with the reactants and significantly improving catalytic efficiency. This approach skips multiple steps required for traditional solid catalyst preparation, such as precipitation, filtration, drying, and calcination, significantly simplifying the catalyst preparation process and reducing production costs. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in detail below with reference to specific examples.

[0020] The present invention first provides a coal liquefaction catalyst based on multivalent composite iron salts. The coal liquefaction catalyst includes a first active component and a second active component. The first active component is a multivalent iron salt solution containing ferrous ions and ferric ions. The second active component is a highly active metal salt solution containing one or more of cobalt ions, molybdenum ions, nickel ions and tungsten ions.

[0021] Based on the coal liquefaction catalyst based on multivalent state composite iron salts provided in the above embodiments, this invention also provides a coal liquefaction method using the coal liquefaction catalyst described in the above embodiments.

[0022] Specifically, the coal liquefaction method includes the following steps: S10. Prepare the first active component and the second active component respectively.

[0023] S20. The first active component and the second active component are loaded onto coal powder individually or in combination by impregnation or spraying to obtain coal powder loaded with catalyst.

[0024] S30. The coal powder with the supported catalyst is mixed with solvent oil to form an oil-coal slurry.

[0025] S40. In the presence of hydrogen, the oil-coal slurry is subjected to a hydrogenation liquefaction reaction, so that the first active component and the second active component loaded on the coal powder generate a catalytic active phase in situ during the reaction, thereby catalyzing the co-liquefaction of coal and oil.

[0026] In some alternative embodiments, the first active component is an aqueous solution prepared using water-soluble ferrous salt and ferric salt; or, the first active component is an aqueous solution prepared using water-soluble ferrous salt and oxidized in air, such that a portion of the ferrous ions are oxidized to ferric ions.

[0027] In some optional embodiments, the ferrous salt is at least one of ferrous sulfate, ferrous nitrate, or ferrous chloride, and the ferric salt is at least one of ferric sulfate, ferric nitrate, or ferric chloride.

[0028] In some optional embodiments, the total concentration of ferrous ions and ferric ions in the first active component is 0.01 mol / L to 3.0 mol / L, for example, 0.01 mol / L, 0.02 mol / L, 0.05 mol / L, 0.08 mol / L, 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, 2.5 mol / L, or 3.0 mol / L.

[0029] In the first active component, the molar ratio of ferrous ions to ferric ions can be any. In some optional embodiments, the molar ratio of ferrous ions to ferric ions in the first active component is preferably (1~10):(10~1), for example, the molar ratio of ferrous ions to ferric ions is 1:10, 2:10, 3:10, 5:10, 8:10, 10:10, 10:1, 10:2, 10:3, 10:5, 10:8, etc. In a more preferred embodiment, the molar ratio of ferrous ions to ferric ions is (4~6):(6~4).

[0030] In some optional embodiments, the second active component is an aqueous solution of a highly active metal salt prepared using one or more of water-soluble cobalt salts, molybdenum salts, nickel salts, and tungsten salts; wherein the cobalt salt is cobalt chloride or cobalt nitrate; the molybdenum salt is ammonium heptamolybdate or ammonium molybdate; the nickel salt is nickel sulfate or nickel nitrate; and the tungsten salt is sodium tungstate or calcium tungstate.

[0031] In some optional embodiments, the total concentration of cobalt ions, molybdenum ions, nickel ions, and tungsten ions in the second active component is 0.01 mol / L to 3.0 mol / L. For example, it can be 0.01 mol / L, 0.02 mol / L, 0.05 mol / L, 0.08 mol / L, 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, 2.5 mol / L, or 3.0 mol / L.

[0032] In some optional embodiments, in step S20, the mass ratio of the first active component added to the coal powder, based on the mass of iron, is (0.01~4):100, for example, 0.01:100, 0.05:100, 0.08:100, 0.1:100, 0.5:100, 1.0:100, 1.5:100, 2.0:100, 3.0:100, or 4.0:100, etc. Based on the total molar amount of cobalt, molybdenum, nickel and tungsten, the molar ratio of the amount of the second active component added to the iron element in the first active component is (0.01~1):100, for example, 0.01:100, 0.05:100, 0.08:100, 0.1:100, 0.2:100, 0.3:100, 0.5:100, 0.8:100 or 1.0:100, etc.

[0033] In some alternative embodiments, the hydrogenation liquefaction reaction is carried out in the presence of sulfur, which is added in the form of elemental sulfur or sulfur-containing compounds.

[0034] The coal liquefaction catalyst and coal liquefaction method based on multivalent complex iron salts provided in this invention have the following beneficial effects: 1. By directly loading multivalent iron salt solutions and highly active metal salt solutions onto pulverized coal, the process skips multiple steps required for the preparation of traditional solid catalysts, such as precipitation, oxidation, filtration, drying, calcination, and pulverization, significantly reducing process complexity and production costs, and showing promising prospects for industrial application.

[0035] 2. A soluble salt solution is used as the precursor of the active component, which is directly loaded onto the surface of pulverized coal through impregnation or spraying, so that Fe... 2+ Fe 3+ The active metals such as cobalt, molybdenum, nickel, and tungsten are uniformly distributed in ionic form on the surface of coal particles, achieving a high degree of molecular / ionic dispersion of active components on the reaction raw materials. Compared with the mechanical mixing or loading of solid catalysts, this significantly improves the contact efficiency between active sites and coal organic matter, which is conducive to giving full play to the catalytic effect of each component.

[0036] 3. Through the synergistic effect of multivalent iron and highly reactive metals (cobalt, molybdenum, nickel, tungsten), effective complementarity between coal pyrolysis and hydrogenation functions is achieved. The iron component plays an important role in coal pyrolysis and free radical stabilization, while the highly reactive metal component significantly enhances hydrogenation capacity. The synergistic effect of the two can effectively inhibit condensation reaction and coking, and improve the yield and selectivity of light oil products in liquefaction products.

[0037] 4. By using the raw coal itself as the dispersion medium and carrier of the active components, the specific surface area and adsorption performance of coal powder are fully utilized. There is no need to introduce external loading materials such as activated carbon, which further reduces the cost of the catalyst. At the same time, it avoids the separation difficulties and process complexity that may be caused by external loading materials.

[0038] Example 1 The mass ratio of iron to 7 g of pulverized coal is 3:100, and the reaction is carried out according to the Fe... 3+ with Fe 2+ The ratio is 6:4. Take 0.5742 g of Fe2(SO4)3 and 0.4180 g of FeSO4, mix them to prepare a 0.0625 mol / L solution. Separately take (NH4)6Mo7O with a Mo:Fe molar ratio of 0.31:100. 24 A solution containing the two active components was prepared and uniformly loaded onto 7 g of pulverized coal by impregnation. At a ratio of 1:1:1, 7 g of coking residue oil and 7 g of tetrahydronaphthalene were added to the pulverized coal loaded with the active substances, along with 0.24 g of elemental sulfur, to prepare an oil-coal slurry. The oil-coal slurry was subjected to a coal-oil co-liquefaction experiment, achieving an oil yield of 83.49% and a coal conversion rate of 99.86%, with a residue rate of 0.14%. This represents an increase of 25.28% and 21.42% in oil yield and coal conversion rate, respectively, compared to commercial Fe2O3 catalysts.

[0039] Example 2 The mass ratio of iron to 7 g of pulverized coal is 3:100, and the reaction is carried out according to the Fe... 3+ with Fe 2+A 0.0625 mol / L solution was prepared by mixing 0.5742 g of Fe2(SO4)3 and 0.4180 g of FeSO4 in a 6:4 ratio. A NiSO4 solution with a Ni:Fe molar ratio of 0.45:100 was also prepared. The solution containing both active components was uniformly loaded onto 7 g of pulverized coal by spraying. 7 g of coking residue oil and 7 g of tetrahydronaphthalene were added to the pulverized coal with the active materials loaded, along with 0.24 g of elemental sulfur, in a 1:1:1 ratio to prepare an oil-coal slurry. The oil-coal slurry was subjected to a coal-oil co-liquefaction experiment. The oil yield and coal conversion rate were 79.50% and 97.96%, respectively, with a residue rate of 2.04%. Compared with commercial Fe2O3 catalysts, the oil yield and coal conversion rate were increased by 21.29% and 19.52%, respectively.

[0040] Example 3 The mass ratio of iron to 7 g of pulverized coal is 3:100, and the reaction is carried out according to the Fe... 3+ with Fe 2+ A 0.0625 mol / L solution was prepared by mixing 0.5742 g of Fe2(SO4)3 and 0.4180 g of FeSO4 in a 6:4 ratio. A CoSO4 solution with a Co:Fe molar ratio of 0.40:100 was also prepared. The solutions containing both active components were uniformly loaded onto 7 g of pulverized coal via impregnation. 7 g of coking residue oil and 7 g of tetrahydronaphthalene were added to the coal powder loaded with active materials in a 1:1:1 ratio, along with 0.24 g of elemental sulfur, to prepare an oil-coal slurry. The oil-coal slurry was subjected to a coal-oil co-liquefaction experiment. The oil yield and coal conversion rate were 81.49% and 98.46%, respectively, with a residue rate of 1.54%. Compared with commercial Fe2O3 catalysts, the oil yield and coal conversion rate were increased by 23.28% and 20.82%, respectively.

[0041] Comparative Example 1 The mass ratio of iron to 7 g of pulverized coal is 3:100, and the reaction is carried out according to the Fe... 3+ with Fe 2+ A 0.0450 g FeSO4 solution was prepared to a concentration of 0.0625 mol / L and uniformly loaded onto 7 g of pulverized coal using a 0:10 ratio. 7 g of coking residue oil and 7 g of tetrahydronaphthalene were added to the coal powder loaded with active materials in a 1:1:1 ratio, along with 0.24 g of elemental sulfur, to prepare an oil-coal slurry. The oil-coal slurry was then subjected to a coal-oil co-liquefaction experiment, yielding an oil yield of 73.29% and a coal conversion rate of 94.19%, with a residue rate of 5.81%.

[0042] Comparative Example 2 The mass ratio of iron to 7 g of pulverized coal is 3:100, and the reaction is carried out according to the Fe... 3+ with Fe 2+ A 0.9570 g Fe2(SO4)3 solution was prepared to a concentration of 0.0625 mol / L and uniformly loaded onto 7 g of pulverized coal using a 10:0 ratio. 7 g of coking residue oil and 7 g of tetrahydronaphthalene were added to the coal powder loaded with active materials in a 1:1:1 ratio, along with 0.24 g of elemental sulfur, to prepare an oil-coal slurry. The oil-coal slurry was then subjected to a coal-oil co-liquefaction experiment, yielding an oil yield of 68.98% and a coal conversion rate of 94.98%, with a residue rate of 5.02%.

[0043] Comparative Example 3 The mass ratio of iron to 7 g of pulverized coal is 3:100, and the reaction is carried out according to the Fe... 3+ with Fe 2+ A 0.0625 mol / L solution was prepared by mixing 0.5742 g of Fe2(SO4)3 and 0.4180 g of FeSO4 in a 6:4 ratio. This solution was then uniformly loaded onto 7 g of pulverized coal via impregnation. 7 g of coking residue oil and 7 g of tetrahydronaphthalene, along with 0.24 g of elemental sulfur, were added to the coal powder loaded with active materials in a 1:1:1 ratio to prepare an oil-coal slurry. The oil-coal slurry was then subjected to a coal-oil co-liquefaction experiment, yielding an oil yield of 74.99% and a coal conversion rate of 96.00%, with a residue rate of 4%.

[0044] The data from Examples 1-3 above show that the method of the present invention significantly improves both oil yield and coal conversion rate compared to traditional catalysts in coal liquefaction, and also significantly reduces residue rate. In Comparative Examples 1-3, the catalyst only contains the first active component, and the first active component in Comparative Examples 1 and 2 only contains ferrous or ferric ions. Comparing Examples 1-3 with Comparative Examples 1-3 shows that the synergistic effect of multivalent iron and highly active metals (cobalt, molybdenum, nickel, tungsten) can significantly improve oil yield and coal conversion rate, and reduce residue rate.

[0045] The above description is only a specific embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A coal liquefaction catalyst based on multivalent state complex iron salts, characterized in that, Includes a first active component and a second active component; The first active component is a multivalent complex iron salt solution containing ferrous ions and ferric ions; The second active component is a solution of highly active metal salts containing one or more of cobalt ions, molybdenum ions, nickel ions, and tungsten ions.

2. The coal liquefaction catalyst according to claim 1, characterized in that, The first active component is an aqueous solution prepared using water-soluble ferrous salt and ferric salt; or, the first active component is an aqueous solution prepared using water-soluble ferrous salt and oxidized in air, so that a portion of the ferrous ions are oxidized to ferric ions.

3. The coal liquefaction catalyst according to claim 2, characterized in that, The ferrous salt is at least one of ferrous sulfate, ferrous nitrate, or ferrous chloride, and the ferric salt is at least one of ferric sulfate, ferric nitrate, or ferric chloride.

4. The coal liquefaction catalyst according to claim 2, characterized in that, In the first active component, the total concentration of ferrous ions and ferric ions is 0.01 mol / L to 3.0 mol / L.

5. The coal liquefaction catalyst according to any one of claims 1-4, characterized in that, In the first active component, the molar ratio of ferrous ions to ferric ions is (1~10):(10~1).

6. The coal liquefaction catalyst according to claim 1, characterized in that, The second active component is a highly active metal salt aqueous solution prepared by using one or more of water-soluble cobalt salt, molybdenum salt, nickel salt and tungsten salt; wherein the cobalt salt is cobalt chloride or cobalt nitrate; the molybdenum salt is ammonium heptamolybdate or ammonium molybdate; the nickel salt is nickel sulfate or nickel nitrate; and the tungsten salt is sodium tungstate or calcium tungstate.

7. The coal liquefaction catalyst according to claim 6, characterized in that, In the second active component, the total concentration of cobalt ions, molybdenum ions, nickel ions and tungsten ions is 0.01 mol / L to 3.0 mol / L.

8. A coal liquefaction method, characterized in that, The coal liquefaction method, employing the coal liquefaction catalyst as described in any one of claims 1-7, comprises the following steps: S10. Prepare the first active component and the second active component respectively; S20. The first active component and the second active component are loaded onto coal powder separately or in combination by impregnation or spraying to obtain coal powder loaded with catalyst. S30. The coal powder with the supported catalyst is mixed with solvent oil to prepare an oil-coal slurry; S40. In the presence of hydrogen, the oil-coal slurry is subjected to a hydrogenation liquefaction reaction, so that the first active component and the second active component loaded on the coal powder generate a catalytic active phase in situ during the reaction, thereby catalyzing the co-liquefaction of coal and oil.

9. The coal liquefaction method according to claim 8, characterized in that, In step S20, the mass ratio of the first active component to the coal powder is (0.01~4):100 based on the mass of iron; and the molar ratio of the second active component to the iron in the first active component is (0.01~1):100 based on the total molar amount of cobalt, molybdenum, nickel and tungsten.

10. The coal liquefaction method according to claim 8 or 9, characterized in that, The hydrogenation liquefaction reaction is carried out in the presence of sulfur, which is added in the form of elemental sulfur or sulfur-containing compounds.