Molybdenum amine complex catalysts, methods for preparing same and uses thereof

Abstract

The present invention discloses a molybdenum amine complex catalyst and its preparation method and its use. The preparation method of the molybdenum amine complex catalyst includes the following steps: in the presence of a dispersion medium, i.e., a hydrocarbon oil, a hexavalent molybdenum compound is reacted with at least one aliphatic amine compound having a carbon number of C4 or more to obtain an active metal catalyst precursor; and the active metal catalyst precursor is uniformly dispersed in the dispersion medium, i.e., a hydrocarbon oil to obtain a molybdenum amine complex catalyst. When the molybdenum amine complex catalyst of the present invention is applied to a direct coal liquefaction reaction, it can greatly reduce the required reaction pressure and greatly improve the conversion rate of coal and the conversion rate of asphaltene and pre-asphaltene to oil, so as to achieve an oil yield equivalent to that of an iron-based catalyst.

Description

[Technical field]

[0001] [Technical field] The present disclosure relates to the technical field of direct coal liquefaction, and in particular to a molybdenum amine complex catalyst and its preparation method and use. [Background technology]

[0002] Direct coal liquefaction is a complex physical and chemical process with many influencing factors. Among them, the reaction rate, conversion rate, oil yield, gas yield and hydrogen consumption in coal liquefaction are greatly affected by the activity and selectivity of the catalyst, so catalysts are an effective means to improve coal liquefaction efficiency and energy utilization rate, realize the commercial value of direct coal liquefaction and maintain competitiveness. How to develop and design catalysts with high catalytic activity, high selectivity and low cost has always been a hot research topic in direct coal liquefaction.

[0003] Compounds containing elements such as Mo, Ni and Fe are effective hydrogenation catalysts and are widely used in direct coal hydroliquefaction reactions. Among them, iron-based catalysts are the most valued as coal liquefaction hydrogenation catalysts because they have high hydrogenation activity for olefins and free radicals, are relatively inexpensive, and are a "cheap and disposable" type of catalyst. However, iron-based catalysts have only moderate catalytic activity for the decomposition of aromatic rings, methylene bridge bonds and alkyl CC, as well as the removal of heteroatoms such as S, N and O. Transition metals such as Mo and Ni not only have high hydrogenation activity but also have high heteroatom removal ability, but are relatively expensive and are mainly used in solvent hydrogenation reactions and hydrogenation reactions of coal liquefaction products. Iron-based catalysts are inexpensive and suitable as disposable catalysts for direct coal liquefaction, but their catalytic activity is relatively low. Research has shown that metallic molybdenum and its molybdates not only have better catalytic activity than iron-based catalysts, but also have a certain selectivity for the chemical bond cleavage of Car-Cal bonds and Car-O bonds in the macromolecular structure of coal, which can further improve the catalytic efficiency and selectivity of direct coal liquefaction. Since the 1920s, molybdenum sulfide catalysts have been used to significantly improve the efficiency of primary coal liquefaction and improve coal liquefaction products. It is generally believed that the main active component in primary coal liquefaction is MoS2, which is generated by decomposition of molybdenum salts or their organic complexes as precursors under liquefaction conditions. However, further research is needed to improve the formation of the active state and performance.

[0004] CN102895973B discloses a composite catalyst for direct coal liquefaction and its preparation method, which uses natural laterite nickel ore as a catalyst or uses laterite nickel ore and other iron ores as raw materials, and uses a catalyst artificially supported with active metal components such as cobalt, molybdenum and nickel. In this method, physical crushing is performed to obtain fine powder with a particle size of 10 nm to 500 μm from laterite nickel ore, thereby improving the dispersibility of the catalyst. When mechanical crushing is performed to reduce the particle size of the catalyst powder, the power and material consumption of the crushing device is large, resulting in a significant increase in the catalyst crushing cost and poor cost-effectiveness. In addition, in this method, active metals such as cobalt, molybdenum and nickel are added for support before the coprecipitation reaction. These expensive non-ferrous metals are lost together with the filtrate in the filtration and washing processes, making it difficult to effectively retain them, and the utilization efficiency of the non-ferrous metals is greatly reduced.

[0005] CN200710032428.4 discloses liquid catalysts, including organic complexed iron catalysts, cobalt catalysts, molybdenum catalysts and boron catalysts. The catalysts disclosed in this document are limited in the types of coal that can be applied, and the catalysts have too many active components, making them difficult to prepare. Summary of the Invention

[0006] In view of the above, the main objective of the present disclosure is to provide a molybdenum amine complex catalyst and its preparation method and use thereof. When the molybdenum amine complex catalyst is applied to a direct coal liquefaction reaction, it can significantly improve the conversion rate of coal and the conversion rate of asphaltene and pre-asphaltene to oil, and can achieve the same oil yield as that of an iron-based catalyst while significantly reducing the required reaction pressure.

[0007] In order to achieve the above object of the present disclosure, a first aspect of the present disclosure provides a method for preparing a molybdenum amine complex catalyst, comprising: reacting a hexavalent molybdenum compound with at least one aliphatic amine compound having a carbon atom of C4 or more in the presence of a carrier hydrocarbon oil to obtain an active metal catalyst precursor; and uniformly dispersing the active metal catalyst precursor in the carrier hydrocarbon oil to obtain a molybdenum amine complex catalyst.

[0008] A second aspect of the present disclosure provides a molybdenum amine complex catalyst prepared by the above method.

[0009] A third aspect of the present disclosure provides a molybdenum amine complex catalyst for direct coal liquefaction, comprising a molybdenum amine complex catalyst uniformly dispersed in a direct liquefaction recycle solvent.

[0010] A fourth aspect of the present disclosure provides a coal oil slurry for direct coal liquefaction, comprising a molybdenum amine complex catalyst uniformly dispersed in a direct liquefaction circulating solvent, as well as coal powder and a sulfur source.

[0011] A fifth aspect of the present disclosure provides a method for direct coal liquefaction, comprising subjecting coal powder to a direct coal liquefaction reaction in the presence of a sulfur source and a molybdenum amine complex catalyst, the source being uniformly dispersed in a direct liquefaction circulating solvent.

[0012] Compared with the prior art, the present disclosure has the following advantages: In the present disclosure, a hexavalent molybdenum compound is reacted with at least one aliphatic amine compound having a carbon atom of C4 or more to obtain an active metal catalyst precursor, and the active metal catalyst precursor is uniformly dispersed in a carrier hydrocarbon oil to obtain a molybdenum amine complex catalyst; the present disclosure uses a carrier hydrocarbon oil as the catalyst matrix oil, which can achieve high dissolution and dispersion of the catalyst in the coal oil slurry, and the high dispersion of the catalyst directly affects the effect of the coal liquefaction reaction and can fully contact with the reactive coal; furthermore, the molybdenum amine complex catalyst obtained in the present disclosure has a mass percentage of molybdenum of 8% or more, has good stability, and is not exfoliated.

[0013] The catalyst preparation method of the present disclosure is simple, and there is no limitation on the type of coal to which the catalyst is applied. Even if the type of coal is different, the difficulty of direct coal liquefaction does not increase, and a better coal conversion rate can be achieved, and the applicability is good.

[0014] The iron-based catalysts referred to in this specification include Fe2O3, FeS2, and FeOOH, which can be used as catalysts for direct liquefaction. The iron-based catalyst is a catalyst that is formed by converting the active phase Fe of magnetite in a vulcanized state in the direct liquefaction reaction. 1-x S, which plays a catalytic role. In the direct coal liquefaction reaction, compared with the above iron-based catalyst, the molybdenum amine complex catalyst of the present disclosure can significantly improve the coal conversion rate and the conversion rate of asphaltene / pre-asphaltene to oil, and can significantly reduce the required reaction pressure, for example, by 6 MPa to 8 MPa, while achieving the same oil yield as the iron-based catalyst.

[0015] Other features and advantages of the present disclosure will be described in detail below through specific embodiments. [Brief description of the drawings]

[0016] [Figure 1] 1 shows an infrared spectrum of the molybdenum amine complex prepared in Example 1 of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Detailed Description Hereinafter, the present application will be further described in conjunction with embodiments, but the present application is not limited to the enumerated embodiments, and also includes equivalent improvements and modifications of the technical solutions defined in the claims appended hereto.

[0018] The endpoints and any values ​​disclosed herein are not intended to be limited to the exact ranges or values, and such ranges or values ​​should be understood to include values ​​close to such ranges or values. For numerical ranges, the endpoints of each range, and the individual point values ​​and individual point values ​​can be combined with each other to form one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0019] In a first aspect, the present disclosure provides a method for preparing a molybdenum amine complex catalyst, comprising the steps of reacting a hexavalent molybdenum compound (A) with at least one aliphatic amine compound (B) having C4 or more carbon atoms in the presence of a carrier fluid hydrocarbon oil to obtain an active metal catalyst precursor (C), and uniformly dispersing the active metal catalyst precursor (C) in the carrier fluid hydrocarbon oil (D) to obtain a molybdenum amine complex catalyst.

[0020] In the study, the inventors of the present disclosure have found that the structure and properties of the catalyst precursor greatly affect the formation and performance of the active state. It is an important research direction in the field of direct liquefaction catalysis to study which precursor catalyst can be effectively converted into the active state, effectively achieve the goal of improving oil yield, reduce the severity of the reaction, tend to ease the reaction conditions, and greatly reduce the cost of coal liquefaction.

[0021] In the present disclosure, preferably, the hexavalent molybdenum compound is one or more selected from oxides or metal salts of hexavalent molybdenum, including, but not limited to, sodium molybdate, potassium molybdate, diamine molybdate, ammonium dimolybdate, ammonium tetramolybdate, ammonium heptamolybdate, and molybdenum trioxide, etc. The aliphatic amine compound (B) is substituted with the hexavalent molybdenum compound with variable valence of molybdenum.

[0022] In the present disclosure, preferably, at least one aliphatic amine compound (B) having C4 or more carbon atoms is selected from C4-C20 aliphatic diamines, including but not limited to one or more of dibutylamine, bis(ethylhexyl)amine, didodecylamine and ditridecylamine; furthermore, the dialkylamine used is preferably ditridecylamine. The inventors of the present disclosure have found in their research that ditridecylamine has good reactivity and compatibility with molybdenum, resulting in high conversion of hexavalent molybdenum compounds to target molybdenum amine complexes, and high molybdenum content in the target product.

[0023] In the present disclosure, the dispersion medium hydrocarbon oil (D) is preferably a low viscosity oil (for example, a kinematic viscosity of 30 mm or less at 20° C.) such as paraffin oil and naphthenic oil. 2 / s or less) and has a low content of impurities. When selecting the type of dispersion medium hydrocarbon oil (D) described above in this disclosure, the main considerations are viscosity and naphthene content. In general, the dispersion medium hydrocarbon oil (D) must maintain a certain fluidity, so the viscosity must not be too high, while considering the use environment of the molybdenum amine complex catalyst prepared therefrom, it is also necessary to select a type of dispersion medium hydrocarbon oil (D) that has good mutual solubility with gasoline / diesel. For example, if naphthene-rich direct liquefaction product oil is used, the catalyst can be sufficiently dissolved and dispersed therein, and if the molybdenum amine complex catalyst obtained using the direct liquefaction product oil is applied to the direct coal liquefaction reaction, the similar solubility characteristics can provide better dispersion and promote good progress of the direct liquefaction reaction; preferably, the naphthene content of the dispersion medium hydrocarbon oil (D) is more than 60%, more preferably 65% ​​to 98%.

[0024] In a specific example, the dispersion medium hydrocarbon oil (D) is naphthene-rich diesel produced by a direct coal liquefaction plant, has a distillation range of 150°C to 250°C, and a density at 20°C of 0.8 g / cm 3 ~0.95g / cm 3 , the kinetic viscosity at 20°C is 20mm2 / s or less, the naphthene content is 85% to 98%.

[0025] In the present disclosure, the hexavalent molybdenum compound (A) and the aliphatic amine compound (B) are reacted preferably at a temperature of 40° C. to 100° C. Furthermore, the reaction temperature is controlled to 65° C. to 80° C. Within this range, the conversion rate of the raw material molybdenum compound to the target molybdenum amine complex can be further improved; more preferably, the reaction temperature is controlled to 75±1° C.

[0026] It can be understood that before mixing and reacting the hexavalent molybdenum compound (A) and the aliphatic amine compound (B), the hexavalent molybdenum compound (A) can be first dispersed in the dispersion medium hydrocarbon oil (D) or dispersed with the aid of stirring in order to disperse the hexavalent molybdenum compound (A) more uniformly in the reaction system. In a specific example, the hexavalent molybdenum compound (A), deionized water, and the dispersion medium hydrocarbon oil (D) are mixed and stirred for a certain period of time to completely disperse the hexavalent molybdenum compound (A) therein. In another specific example, the hexavalent molybdenum compound (A), deionized water, and the dispersion medium hydrocarbon oil (D) are uniformly dispersed under the emulsifying action of the emulsifier.

[0027] In the present disclosure, an exothermic reaction takes place when the hexavalent molybdenum compound (A) is mixed with the aliphatic amine compound (B). Preferably, the aliphatic amine compound (B) can be slowly added dropwise to the hexavalent molybdenum compound (A) at a constant rate for 1 hour or less, preferably 10 minutes to 40 minutes, so that the hexavalent molybdenum compound (A) and the aliphatic amine compound (B) can be uniformly mixed and reacted completely. Preferably, the molar ratio of the hexavalent molybdenum compound (A) to the aliphatic amine compound (B) is 2 to 3.5:1, more preferably 2 to 3:1, such as 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1 or other values ​​within this range. When the molar ratio is in the above preferred range, the molybdenum content in the molybdenum amine complex is relatively high, for example approaching 10%.

[0028] It is understood that after mixing and reacting the hexavalent molybdenum compound (A) and the aliphatic amine compound (B), the water content in the catalyst product can be removed as necessary. For example, the reaction mixture is distilled under a vacuum of -0.080 MPa to -0.099 MPa at a temperature of 97°C to 102°C until the water content is eliminated and the distillate flows out, thereby obtaining a uniform molybdenum amine complex catalyst in the form of an emulsion.

[0029] In a second aspect, the present disclosure provides a molybdenum amine complex catalyst prepared by the above method, the catalyst having a molybdenum content of 8% by weight or more and good stability without exfoliation.

[0030] In a third aspect, the present disclosure provides a molybdenum amine complex catalyst for direct coal liquefaction, comprising a molybdenum amine complex catalyst uniformly dispersed in a direct liquefaction recycle solvent.

[0031] According to the actual dispersion needs, the molybdenum amine complex catalyst can be completely mixed with the direct liquefaction circulating solvent under the emulsifying action of the emulsifier, so that the catalyst can be completely dispersed in the solvent. Preferably, the molybdenum amine complex catalyst is added in an amount such that the mass ratio of Mo to dry coal is 0.05%-1%, and within this range, a better catalytic effect can be obtained. Furthermore, the molybdenum amine complex catalyst is added in an amount such that the mass ratio of Mo to dry coal is 0.1%-0.3%, for example, 0.1%, 0.15%, 0.2%, 0.25%, 0.3% or other values ​​within this range.

[0032] In a fourth aspect, the present disclosure provides a coal oil slurry for direct coal liquefaction, comprising a molybdenum amine complex catalyst, a reacting coal powder and a sulfur source uniformly dispersed in a direct liquefaction circulating solvent, the three being thoroughly mixed to a homogeneous state and then compounded into the reacting coal oil slurry.

[0033] In the present disclosure, the sulfur source is elemental sulfur or a sulfur-containing compound such as carbon disulfide, and preferably, sulfur is added in an amount such that the atomic ratio of S to Mo is 1 to 3. In the direct coal liquefaction reaction, the active state in which the molybdenum catalyst functions is MoS2, so it is necessary to ensure a sufficient amount of S to convert the precursor to the active state. Furthermore, sulfur is added in an amount such that the atomic ratio of S to Mo is 2 to 2.5, for example, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, or other values ​​within this range.

[0034] In a fifth aspect, the present disclosure provides a method for direct coal liquefaction, comprising subjecting coal powder to a direct coal liquefaction reaction in the presence of a sulfur source and a molybdenum amine complex catalyst uniformly dispersed in a direct liquefaction circulating solvent.

[0035] In the present disclosure, the above direct coal liquefaction reaction is preferably carried out under conditions of a reaction temperature of 450°C to 460°C, a reaction pressure of 10 MPa to 15 MPa, and a reaction residence time of 0.5 hours to 2 hours, to obtain a gas phase product and a liquid phase product, which are subjected to yield measurement and composition analysis to calculate the direct liquefaction conversion rate and the oil yield.

[0036] Furthermore, the above direct coal liquefaction reaction is carried out at a temperature of 455±2°C and a reaction pressure of 12±0.2MPa for a reaction residence time of 1±0.1 hours. The above reaction temperature affects the degree of pyrolysis of coal into small molecules.

[0037] In the direct coal liquefaction reaction, reducing the reaction pressure can reduce both the severity of the reaction and the investment cost of the entire plant. However, in general, reducing the reaction pressure will inevitably affect the reaction effects such as coal conversion and oil yield. When the molybdenum amine complex catalyst of the present disclosure is applied to the direct coal liquefaction reaction, the above problem of the imbalance between the reaction pressure and the reaction effect is solved. That is, the present disclosure can greatly improve the coal conversion rate and the conversion rate of asphaltene and pre-asphaltene to oil, and can greatly reduce the required reaction pressure while achieving the same oil yield as that of the iron-based catalyst.

[0038] The present disclosure will be described in detail below through examples: The fine coal used in the examples was mined from the Shendong mining area in Shenhua, and the coal quality analysis is shown in Table 1. The coal samples were pre-ground to 74 μm or less for later use.

[0039] [Table 1]

[0040] The meaning of each symbol and the measurement method in Table 1 are as follows: For industrial analysis, see M ad refers to air-dry basis moisture; A d refers to dry basis ash; V dafrefers to the dry ashless volatile components, which were determined according to the methods of GB / T211-2017 and GB / T212-2008.

[0041] For elemental analysis, see FC daf refers to dry ashless fixed carbon; C, H, O, N and S respectively refer to the contents of each element, which were determined according to the methods of GB / T214-2007, GB / T476-2008 and GB / T19227-2008.

[0042] For the rock analysis, Vitrinite refers to the content of vitrinite; Inertinite refers to the content of inertinite; Exinite refers to the content of exinite, which were determined according to the method of GB / T8899-2013.

[0043] Unless otherwise noted, other raw materials in this disclosure are obtainable from commercial sources.

[0044] The direct liquefaction circulating solvent used in the examples is an intermediate product of the coal liquefaction process. After partially hydrogenating the aromatic hydrocarbons, it serves as a circulating solvent, part of which is used as a solvent for preparing the coal oil slurry, and the other part is used to supply hydrogen for the direct liquefaction reaction. The main properties of the circulating solvent are shown in Table 2.

[0045] [Table 2]

[0046] Example 1 1 mol of molybdenum trioxide powder, 2 mol of deionized water, and 300 g of diesel produced in a direct liquefaction plant (characteristics and composition are shown in Table 3) were mixed and emulsified with an emulsifier for a certain period of time to thoroughly disperse the molybdenum trioxide. Then, 0.5 mol of ditridecylamine was added dropwise over 30 minutes and reacted at 75°C for 2 hours. The resulting reaction mixture was distilled at 100°C and -0.099KPa for 1 hour to remove moisture, thereby obtaining a molybdenum amine complex catalyst. The molybdenum content of this catalyst was measured to be 10.08%.

[0047] The infrared spectrum of the organomolybdenum amine complex is shown in Figure 1. As can be seen from Figure 1, in the functional group region, -1 A characteristic peak of secondary amines, i.e., the NH stretching absorption peak, appears around 2959 cm -1 ~2837cm -1 The absorption peaks are due to the asymmetric CH2 stretching vibration and the symmetric CH2 stretching vibration, respectively; the CC stretching vibration and the CN stretching vibration are at 1536 cm -1 ~968cm -1 Occurs at 732cm -1 The absorption peak of belongs to the vibration of Mo-O group (within the fingerprint region), and the peak that appears in the fingerprint region indicates that Mo-O is bonded to dialkylamine. In addition, after the reaction, no solid particles were observed, and all the substances became liquid oil-soluble substances, which also shows that MoO3 is bonded to dialkylamine and replaced H on dialkylamine.

[0048] [Table 3]

[0049] 0.71 g of the above organic molybdenum amine complex (the mass ratio of Mo to the dry coal powder is 0.25%) was added as a catalyst to 42 g of direct liquefaction circulating solvent, and mixed uniformly by sufficient stirring together with an emulsifier, so that the catalyst was sufficiently dispersed in the direct liquefaction circulating solvent to obtain a catalyst mixture.

[0050] 28 g of dry coal powder was added to the high-pressure reactor, followed by the above catalyst mixture, and 0.047 g of powdered elemental S (atomic ratio of S to Mo is 2.3:1). Hydrogen was charged until the pressure reached 6 MPa, and the temperature of the high-pressure reactor was raised to 455°C by program heating, with the average pressure during the reaction being 12.0 MPa (in the following experiments, the reaction pressures were all within the range of the target pressure ±0.03, which is a reasonable pressure fluctuation range). Then, the reaction was carried out at a constant temperature for 60 minutes. Gas-phase and liquid-phase products were obtained, which were subjected to yield measurement and composition analysis to calculate performance data such as direct liquefaction conversion and oil yield.

[0051] After the reaction was completed, gaseous and liquid-solid products were obtained. The composition of the gaseous product was measured by gas chromatography, and the liquid-solid product was subjected to Soxhlet extraction with n-hexane and tetrahydrofuran in succession. The n-hexane-soluble material was oil, and the tetrahydrofuran-soluble material was asphaltene and pre-asphaltene. The tetrahydrofuran-insoluble material was dried and calcined in a muffle furnace at 815°C for 6 hours, and the residue was the residual ash (RA). The coal conversion rate (X), gas yield (G), hydrogen consumption (H), oil yield (O), and asphaltene (including pre-asphaltene and asphaltene, A) yield were calculated according to the following formula: X=1-(TI-RA) / F daf A=(HI-TI) / F daf H=(H0-H1) / F daf G=(G1-H1) / F daf O=X+HGWA Here, F daf : mass of dry and ash-free base coal (in g); H0: mass of hydrogen charged in the reactor before the reaction (in g); H1: mass of hydrogen remaining in the reactor after the reaction (in g); G1: mass of gas in the reactor after reaction (in g); HI: mass of n-hexane insoluble matter (in g); TI: mass of tetrahydrofuran insoluble matter (in g); RA: mass of residue after calcination of tetrahydrofuran insoluble material (in g); H: hydrogen consumption; G: gas generation rate; W: water yield, the oxygen element in coal minus the oxygen element in gas products CO and CO2, mass of water / F daf Converted to; A: Asphalt yield, mass difference between n-hexane insolubles and tetrahydrofuran insolubles / F daf ; O: oil yield.

[0052] Example 2 The molybdenum amine complex catalyst was prepared in the same manner as in Example 1.

[0053] 0.57 g of the above catalyst (the mass ratio of Mo to the dry coal powder is 0.2%) was added directly to 42 g of liquefied circulating solvent, and thoroughly stirred together with the emulsifier to mix uniformly, so that the catalyst was completely dispersed in the circulating solvent.

[0054] The above catalyst was used in a direct coal liquefaction process, and the products were analyzed in the same manner as in Example 1.

[0055] Example 3 1 mol of molybdenum trioxide powder, 2 mol of deionized water, and 300 g of commercially available Karamei KN4010 naphthenic oil were mixed and emulsified with an emulsifier for a certain period of time to thoroughly disperse the molybdenum trioxide. Then, 0.5 mol of ditridecylamine was added dropwise over 1 hour and reacted at 75°C for 2 hours. The reaction mixture was then distilled at 100°C and -0.099KPa for 1 hour to remove water, yielding a molybdenum amine complex catalyst. The molybdenum content of this catalyst was measured to be 9.54%.

[0056] 0.66 g of the above catalyst (the mass ratio of Mo to the dry coal powder is 0.25%) was added to 42 g of direct liquefaction circulating solvent, and mixed homogeneously by thorough stirring together with the emulsifier to completely disperse the catalyst in the circulating solvent.

[0057] The above catalyst was used in a direct coal liquefaction process, and the products were analyzed in the same manner as in Example 1.

[0058] Example 4 1 mol of molybdenum trioxide powder, 2 mol of deionized water, and 300 g of diesel produced in a direct liquefaction plant were mixed and emulsified with an emulsifier for a certain period of time to thoroughly disperse the molybdenum trioxide. Then, 0.3 mol of didodecylamine was added dropwise over 1 hour and reacted at 75°C for 2 hours. The reaction mixture was then distilled at 100°C and -0.099KPa for 1 hour to remove moisture, yielding a molybdenum amine complex catalyst. The molybdenum content of this catalyst was measured to be 9.63%.

[0059] 0.73 g of the above catalyst (the mass ratio of Mo to the dry coal powder is 0.25%) was added to 42 g of direct liquefaction circulating solvent, and mixed homogeneously by thorough stirring together with the emulsifier to completely disperse the catalyst in the circulating solvent.

[0060] The above catalyst was used in a direct coal liquefaction process, and the products were analyzed in the same manner as in Example 1.

[0061] Example 5 1 mol of molybdenum trioxide powder, 2 mol of deionized water, and 200 g of diesel produced in a direct liquefaction plant were mixed and emulsified with an emulsifier for a certain period of time to thoroughly disperse the molybdenum trioxide. Then, 0.5 mol of didodecylamine was added dropwise over 1 hour and reacted at 65°C for 2 hours. The reaction mixture was then distilled at 100°C and -0.099KPa for 1 hour to remove moisture, yielding a molybdenum amine complex catalyst. The molybdenum content of this catalyst was measured to be 8.33%.

[0062] 0.84 g of the above catalyst (the mass ratio of Mo to the dry coal powder is 0.25%) was added directly to 42 g of liquefied circulating solvent, and mixed homogeneously with the emulsifier by thorough stirring to completely disperse the catalyst in the circulating solvent.

[0063] The above catalyst was used in a direct coal liquefaction process, and the products were analyzed in the same manner as in Example 1.

[0064] Example 6 The same procedure as in Example 1 was repeated except that 1 mol of molybdenum trioxide powder was replaced with 1 mol of sodium molybdate powder. The molybdenum content in the molybdenum amine complex catalyst was measured and found to be 8.16%.

[0065] Example 7 The same procedure as in Example 1 was carried out except that 1 mol of ditridecylamine was replaced with 1 mol of bis(ethylhexyl)amine. The molybdenum content in the molybdenum amine complex catalyst was measured and found to be 7.94%.

[0066] Example 8 The same procedure as in Example 1 was carried out except that molybdenum trioxide was reacted with ditridecylamine at 80° C. for 2 hours. The molybdenum content in the molybdenum amine complex catalyst was measured and found to be 9.72%.

[0067] Example 9 The same procedure as in Example 1 was carried out, except that the molybdenum amine complex catalyst was added in an amount such that the mass ratio of Mo to the dry coal was 0.05%.

[0068] Example 10 The same operation as in Example 1 was carried out, except that the molybdenum amine complex catalyst was added in an amount such that the mass ratio of Mo to the dry coal was 0.1%.

[0069] Example 11 The molybdenum amine complex catalyst was prepared in the same manner as in Example 1.

[0070] 0.71 g of the above organic molybdenum amine complex (the mass ratio of Mo to the dry coal powder is 0.25%) was added as a catalyst to 42 g of direct liquefaction circulating solvent, and mixed uniformly by sufficient stirring together with an emulsifier, so that the catalyst was sufficiently dispersed in the direct liquefaction circulating solvent to obtain a catalyst mixture.

[0071] 28 g of dry coal powder was added to the high-pressure reactor, followed by the catalyst mixture described above, and then 0.047 g of powdered elemental S (atomic ratio of S to Mo is 2.3:1). Hydrogen was charged until the pressure reached 5 MPa, and the temperature of the high-pressure reactor was raised to 460°C by programmed heating, and the average pressure during the reaction was set to 10.01 MPa, after which the reaction was carried out at a constant temperature for 60 minutes. Gas and liquid phase products were obtained, which were subjected to yield measurement and composition analysis to calculate performance data such as direct liquefaction conversion and oil yield.

[0072] Example 12 The molybdenum amine complex catalyst was prepared in the same manner as in Example 1.

[0073] 0.71 g of the above organic molybdenum amine complex (the mass ratio of Mo to the dry coal powder is 0.25%) was added as a catalyst to 42 g of direct liquefaction circulating solvent, and mixed uniformly by thoroughly stirring together with an emulsifier, so that the catalyst was sufficiently dispersed in the direct liquefaction circulating solvent, and a catalyst mixture was obtained.

[0074] 28 g of dry coal powder was added to the high-pressure reactor, followed by the above catalyst mixture, and then 0.047 g of powdered elemental S (atomic ratio of S to Mo is 2.3:1). Hydrogen was charged until the pressure reached 8 MPa, and the temperature of the high-pressure reactor was raised to 450°C by program heating, and the average pressure during the reaction was set to 15.02 MPa, after which the reaction was carried out at a constant temperature for 60 minutes. Gas and liquid phase products were obtained, which were subjected to yield measurement and composition analysis to calculate performance data such as direct liquefaction conversion and oil yield.

[0075] Comparative Example 1 1 mol of molybdenum trioxide powder and 2 mol of deionized water were mixed, and 0.5 mol of ditridecylamine was added dropwise over 30 minutes. The mixture was reacted at 75°C for 2 hours, and then the reaction mixture was distilled at 100°C and -0.099KPa for 1 hour to remove water, yielding a molybdenum amine complex catalyst. The molybdenum content of this catalyst was measured to be 18.32%.

[0076] The above catalyst was used in a direct coal liquefaction process, and the products were analyzed in the same manner as in Example 1.

[0077] The organic molybdenum amine complex obtained in this comparative example was in powder form because it did not contain a dispersion medium hydrocarbon oil. Although the molybdenum content was high, the oil solubility and dispersibility in the direct liquefaction coal oil slurry were not as good as those of the molybdenum amine complex product obtained in Example 1, which directly affected the catalytic performance for the direct liquefaction reaction.

[0078] Comparative Example 2 Powdered molybdenum hexacarbonyl was used as the molybdenum source of the catalyst. The coal oil slurry of the catalyst was prepared as follows: 0.2 g of powdered molybdenum hexacarbonyl (mass ratio of Mo to dry coal powder is 0.25%) was thoroughly mixed with 42 g of circulating solvent, and the mixture thus obtained was stirred uniformly, and then 28 g of coal powder and 0.047 g of sulfur powder were added to the mixture, which was thoroughly mixed and stirred uniformly, and then added to the high-pressure reactor.

[0079] The catalyst evaluation method in the high pressure reactor and the product analysis method were the same as in Example 1.

[0080] Comparative Example 3 The catalyst was selected as the hydrated iron oxide (FeOOH) catalyst used in the direct liquefaction demonstration plant, the iron content of the catalyst was 5.95%, the iron catalyst was added in an amount such that the mass ratio of Fe to dry coal powder was 1%, and S was added in an amount such that the atomic ratio of S to Fe was 2:1. The coal oil slurry of the iron-based catalyst was prepared as follows: 5.41 g of hydrated iron oxide catalyst (containing 4.58 g of coal powder in it), 23.42 g of dry coal powder, 42 g of circulating solvent, and 0.32 g of sulfur powder were thoroughly mixed and stirred uniformly to prepare the coal oil slurry of the iron-based catalyst, which was then added to the high-pressure reactor.

[0081] The catalyst evaluation method in the high pressure reactor and the product analysis method were the same as in Example 1.

[0082] Comparative Example 4 The catalyst was selected as the hydrated iron oxide catalyst used in the direct liquefaction demonstration plant, the iron content of the catalyst was 5.95%, the iron catalyst was added in an amount such that the mass ratio of Fe to dry coal powder was 1%, and S was added in an amount such that the atomic ratio of S to Fe was 2:1. The coal oil slurry of the iron-based catalyst was prepared as follows: 5.41 g of hydrated iron oxide catalyst (containing 4.58 g of coal powder in it), 23.42 g of dry coal powder, 42 g of circulating solvent, and 0.32 g of sulfur powder were thoroughly mixed and stirred uniformly to prepare the coal oil slurry of the iron-based catalyst, which was then added to the high-pressure reactor.

[0083] The reaction pressure in the high-pressure reactor evaluation method for the catalyst was 19 MPa, and the other reaction conditions and product analysis methods were the same as in Example 1.

[0084] The reaction pressure and yield test result data for the above examples are shown in Table 4: [Table 4]

[0085] It is understood that the above examples of the present disclosure are not limited to the embodiments of the present disclosure, but are examples given only for the purpose of clearly explaining the present disclosure. Those skilled in the art can make various modifications or variations based on the above description. All embodiments cannot be exhaustively listed here. Any obvious modifications or variations that extend the technical solutions of the present disclosure are within the spirit encompassed by the present disclosure.

Claims

1. A method for preparing a molybdenum amine complex catalyst, comprising the steps of: reacting a hexavalent molybdenum compound with at least one aliphatic amine compound having C4 or more carbon atoms in the presence of a hydrocarbon oil dispersion medium to obtain an active metal catalyst precursor; and uniformly dispersing the active metal catalyst precursor in the hydrocarbon oil dispersion medium to obtain a molybdenum amine complex catalyst.

2. 2. The method for preparing the molybdenum amine complex catalyst according to claim 1, wherein the hexavalent molybdenum compound is one or more selected from oxides or metal salts of hexavalent molybdenum, including but not limited to one or more of sodium molybdate, potassium molybdate, diamine molybdate, ammonium dimolybdate, ammonium tetramolybdate, ammonium heptamolybdate and molybdenum trioxide.

3. 2. The method for preparing a molybdenum amine complex catalyst according to claim 1, wherein the at least one aliphatic amine compound having C4 or more carbon atoms is selected from C4-C20 aliphatic diamines, including but not limited to one or more of dibutylamine, bis(ethylhexyl)amine, didodecylamine and ditridecylamine.

4. 2. The method for preparing the molybdenum amine complex catalyst according to claim 1, wherein the carrier fluid hydrocarbon oil is a mineral oil with low viscosity and low impurity content, including but not limited to paraffin oil and naphthenic oil.

5. The method for preparing the molybdenum amine complex catalyst according to any one of claims 1 to 3, wherein the hexavalent molybdenum compound and the aliphatic amine compound are reacted at a temperature of 40°C to 100°C, preferably 65°C to 80°C, more preferably 75±1°C.

6. A molybdenum amine complex catalyst prepared by the method for preparing a molybdenum amine complex catalyst according to any one of claims 1 to 5.

7. A molybdenum amine complex catalyst for direct coal liquefaction, comprising the molybdenum amine complex catalyst prepared by the method for preparing a molybdenum amine complex catalyst according to any one of claims 1 to 5 or the molybdenum amine complex catalyst according to claim 6, which is uniformly dispersed in a direct liquefaction circulating solvent.

8. A coal oil slurry for direct coal liquefaction, comprising the molybdenum amine complex catalyst prepared by the method for preparing a molybdenum amine complex catalyst according to any one of claims 1 to 5 or the molybdenum amine complex catalyst according to claim 6, which is uniformly dispersed in a direct liquefaction circulating solvent, as well as coal powder and a sulfur source.

9. 13. A method for direct coal liquefaction, comprising: subjecting coal powder to a direct coal liquefaction reaction in the presence of a sulfur source and a molybdenum amine complex catalyst prepared by the method for preparing a molybdenum amine complex catalyst according to any one of claims 1 to 5 or the molybdenum amine complex catalyst according to claim 6, all of which are uniformly dispersed in a direct liquefaction circulating solvent.

10. The method for direct coal liquefaction according to claim 9, wherein the direct coal liquefaction reaction is carried out at a reaction temperature of 450° C. to 460° C., a reaction pressure of 10 MPa to 15 MPa, and a reaction residence time of 0.5 hours to 2 hours.

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