Catalyst coal-oil slurry and its preparation method, method for direct coal liquefaction, and use

Abstract

The present invention relates to the field of direct coal liquefaction, and discloses a catalytic coal-oil slurry and its preparation method, method of direct coal liquefaction, and use. The method includes mixing an oil-soluble molybdenum source, a solvent, pulverized coal, and an optional sulfur source to obtain the catalytic coal-oil slurry. When the catalytic coal-oil slurry is used for direct coal liquefaction, it can achieve a higher oil yield and reduce the production cost.

Description

Detailed description of the invention

[0001] [Technical Field] The present invention relates to the technical field of direct coal liquefaction, and more specifically to catalyst oil-coal slurry and methods for preparing the same, methods for direct coal liquefaction, and their use.

[0002] 〔background〕 Direct coal liquefaction is a clean coal technology that converts coal into liquid products by introducing hydrogen into the molecular structure of coal and its derivatives under high temperature and pressure conditions, with the assistance of a hydrogen-donating solvent and a catalyst. In the early stages of direct liquefaction development, two crucial influencing factors—the coal liquefaction catalyst and the pre-hydrogenation of the solvent—had not been discovered to facilitate liquefaction. Therefore, the reaction conditions for coal liquefaction at that time were quite harsh, with reaction pressures as high as 70 MPa. Over 100 years since the development of direct coal liquefaction, research in various countries has focused on the use of catalysts and solvent hydrogenation techniques, thus tending to relax the reaction conditions. However, current direct coal liquefaction technologies still face the problems of low oil yield and the high production costs resulting from this low yield. Therefore, developing a direct coal liquefaction technology that can significantly improve oil yield is a matter of urgency.

[0003] 〔overview〕 The object of the present invention is to overcome the aforementioned problems in the prior art and to provide a catalyst oil-coal slurry, a method for preparing the same, a method for direct coal liquefaction, and its use. The use of catalyst oil-coal slurry for direct coal liquefaction can yield higher oil yields and reduce production costs.

[0004] To achieve the above-mentioned objective, a first aspect of the present invention is a method for preparing a catalyst oil-coal slurry, The present invention provides a method comprising the step of mixing an oil-soluble molybdenum source, a solvent, coal powder, and an arbitrary sulfur source to obtain the catalyst oil-coal slurry.

[0005] A second aspect of the present invention comprises an oil-soluble molybdenum source, a solvent, coal powder, and an optional sulfur source. or A catalyst oil-coal slurry prepared by the method described in the first embodiment is provided.

[0006] In a third aspect, the present invention relates to a process of subjecting the catalyst oil-coal slurry described in the second aspect to direct coal liquefaction; or A process of subjecting coal powder to direct coal liquefaction in the presence of a solvent, an oil-soluble molybdenum source, and an optional sulfur source; The present invention provides a method for the direct liquefaction of coal, including the method described above.

[0007] In a fourth aspect, the present invention provides the use of the catalyst oil-coal slurry described in the second aspect, or the method described in the first aspect, in direct coal liquefaction.

[0008] Through the above technical solutions, the present invention can achieve the following beneficial effects.

[0009] 1. Compared to prior art, in the catalyst oil-coal slurry provided by the present invention, the catalyst is highly dispersed therein, has better dispersibility under liquefaction conditions, and is highly supported on coal powder. After conversion to molybdenum disulfide, the catalyst has higher activity and can catalyze the reaction better, and can effectively prevent polymer aggregation during the reaction.

[0010] 2. Compared to existing iron-based catalysts, using the catalyst oil-coal slurry provided by the present invention for direct coal liquefaction under the same liquefaction conditions can increase the oil yield by approximately 10 percentage points, significantly improve the conversion rate, and thereby reduce production costs.

[0011] 3. In particular, when the oil-soluble molybdenum source is molybdenum dialkyldithiophosphate and molybdenum dialkyldithiocarbamate, these two substances are inexpensive and commonly used lubricating oil additives that do not require an additional sulfur source, thus reducing the complexity of the work and further lowering production costs. In addition, when the oil-soluble molybdenum source is molybdenum dialkyldithiocarbamate, the use of phosphorus is avoided, thus further reducing environmental pollution, and the chemical stability is better, which is more advantageous than a direct liquefaction reaction.

[0012] [Detailed explanation] The endpoints and any values ​​of the ranges disclosed herein are not limited to exact ranges or values, and it should be understood that the endpoints and any values ​​of those ranges include values ​​that approximate those ranges or values. With respect to ranges of values, the endpoints of each range, the values ​​of each range and individual points, and the values ​​of individual points can be combined with each other to produce one or more new ranges of values, and these ranges of values ​​should be considered specifically disclosed herein.

[0013] In a first embodiment, the present invention relates to a method for preparing a catalyst oil-coal slurry, The present invention provides a method comprising the step of mixing an oil-soluble molybdenum source, a solvent, coal powder, and an arbitrary sulfur source to obtain the catalyst oil-coal slurry.

[0014] Current direct coal liquefaction technologies still face problems such as low oil yields and high production costs.

[0015] The inventors of the present invention have found in their research that using the above-described method for preparing a catalyst oil-coal slurry, particularly the use of the above-described oil-soluble molybdenum source as a catalyst, not only avoids the problems of high water consumption and complicated preparation processes in the preparation of conventional water-soluble and highly dispersed catalysts, but also avoids the problems of large particle size and poor dispersibility of powdered inorganic catalysts. The oil-soluble molybdenum source is highly dispersed in the catalyst oil-coal slurry and highly supported on coal powder, and is converted into ultrafine catalyst molybdenum disulfide under liquefaction conditions. This catalyst molybdenum disulfide has better activity and can exhibit higher hydrogenation catalytic activity, thus enabling higher oil yield and conversion rates, and effectively preventing polymer aggregation during the reaction. In addition, depending on the specific oil-soluble molybdenum source used, it is possible to decide whether or not to add a sulfur source. Furthermore, the inventors of the present invention have also found that using the above-described catalyst oil-coal slurry can yield significantly higher oil yields under the same liquefaction conditions as catalyst oil-coal slurries using iron-based catalysts.

[0016] According to the present invention, preferably, the amount of molybdenum element in the oil-soluble molybdenum source is 0.005 to 1 part by weight, preferably 0.1 to 0.3 parts by weight, and more preferably 0.2 to 0.25 parts by weight, per 100 parts by weight of coal powder. The inventors of the present invention have found in their research that when the above range is satisfied, a significantly high catalytic effect can be obtained, resulting in higher oil yield and conversion rate.

[0017] According to the present invention, the oil-soluble molybdenum source is preferably selected from at least one of molybdenum phosphate, hexacarbonyl molybdenum, molybdenum naphthenate, molybdenum carboxylic acid, molybdenum sulfonic acid, hydroxythiol molybdenum (molybdenum hydroxythiol), and molybdenum xanthogenic acid. More preferably, the oil-soluble molybdenum source is at least one of molybdenum dialkyldithiophosphate (a type of molybdenum phosphate), molybdenum dialkyldithiocarbamate (a type of molybdenum carboxylic acid), hexacarbonyl molybdenum, and molybdenum naphthenate, and more preferably at least one of molybdenum dialkyldithiophosphate (MoDTP) and molybdenum dialkyldithiocarbamate (MoDTC).

[0018] Naphthenic acid is a mixture of organic acids in the form of a dark oil, separated from petroleum products during refining. The corresponding prepared molybdenum naphthenate is also a mixture, and it should be understood that molybdenum naphthenate is mainly a carboxyl derivative of a five-membered carbon ring. In addition, in molybdenum dialkyldithiocarbamate, different lengths of the alkyl carbon chain correspond to different specific substances, and the same is true for molybdenum dialkyldithiophosphate; that is, in molybdenum dialkyldithiophosphate, different lengths of the alkyl carbon chain correspond to different specific substances. For molybdenum dialkyldithiocarbamate, if the alkyl carbon chain has fewer carbon atoms (e.g., 2-6, e.g., 3, 4, or 5), the substance is generally in the form of a powder (solid), and if the alkyl carbon chain has a larger number of carbon atoms (e.g., 12-14), the substance is generally in the form of an oil (liquid). Molybdenum dialkyldithiophosphate is generally in the form of an oil (liquid). Liquid molybdenum dialkyldithiocarbamate is even more preferred.

[0019] In the research, the inventors of the present invention have found that the use of an oil-soluble molybdenum source as described above can achieve a better catalytic effect and obtain a higher oil yield. In particular, molybdenum dialkyldithiophosphate or molybdenum dialkyldithiocarbamate is a commonly used component in lubricating oils. The component is inexpensive, can reduce production costs, and can directly decompose to form MoS2 with a direct catalytic effect under liquefaction conditions without the need to add additional sulfur for sulfidation, making the production operation simpler and more cost-effective. The inventors of the present invention have further found in their research that when liquid molybdenum dialkyldithiocarbamate is used, not only can a better dispersion effect and a higher oil yield be obtained, but the use of phosphorus can also be avoided, further reducing the impact on the environment.

[0020] According to the present invention, preferably, the amount of the solvent is 80 to 220 parts by weight, preferably 100 to 190 parts by weight, and more preferably 120 to 150 parts by weight with respect to 100 parts by weight of the coal powder.

[0021] According to the present invention, preferably, the solvent is a hydrogen-donating solvent, and the hydrogen-donating solvent has a ρ lower than 0.98 g·cm 2 a kinematic viscosity at 40 °C lower than 5 mm 20 / s, and a molar ratio of H to C higher than 0.25. The hydrogen-donating solvent refers to a solvent that can dissolve coal during the coal liquefaction process (i.e., swell the coal and then form a uniform oil-coal slurry with the hydrogen-donating solvent), and can diffuse hydrogen to the surface of the coal or the catalyst to supply and transfer hydrogen. The solvent also has the effect of preventing the polycondensation of free radical fragments due to the thermal decomposition of coal.

[0022] ​​The hydrogen-donating solvent may contain one or more of tetrahydronaphthalene, dihydrophenanthrene, and dihydroanthracene. In direct coal liquefaction, the hydrogen-donating solvent used may generally be the self-generated circulating solvent for direct coal liquefaction. For example, in CN104893751A, partially liquefied oil was used as the circulating solvent. During the continuous operation of a direct coal liquefaction apparatus, it should be understood that the mixed oil of medium oil and heavy oil generated by direct coal liquefaction itself is called the self-generated circulating solvent for direct coal liquefaction. The use of such a solvent not only serves as a hydrogen-donating solvent but can also recycle materials and avoid waste. ρ 20 ρ refers to the density measured at 20 °C, and the kinematic viscosity is measured by the method in GB / T265 - 1988. The molar ratio of H to C is an index of the hydrogen content of the solvent, and the higher the ratio, the stronger the hydrogen-donating ability.

[0023] The use of the solvent as described above can further improve the dispersibility of the oil-soluble molybdenum source in the catalyst oil - coal slurry, and can further control the concentration of each material within a more appropriate range, thereby further improving the oil yield.

[0024] According to the present invention, the sulfur source is a sulfur-containing substance that can convert the oil-soluble molybdenum source into a sulfur-containing substance (e.g., molybdenum disulfide). Therefore, when the oil-soluble molybdenum source itself contains sulfur and can be converted into molybdenum disulfide (especially under direct coal liquefaction conditions), there is no need to additionally introduce a sulfur source. Preferably, the amount of the sulfur source is such that the molar ratio of sulfur element to molybdenum element in the catalyst oil - coal slurry is 0 to 3.5, preferably 2 to 2.8, more preferably 2.2 to 2.5. It should be understood that the oil-soluble molybdenum source may also contain sulfur element, and the amount of the sulfur source is based on the principle that the total molar ratio of sulfur element to molybdenum element in the catalyst oil - coal slurry satisfies the above molar ratio.

[0025] According to the present invention, preferably, the sulfur source is selected from at least one of elemental sulfur, inorganic sulfur, and organic sulfur, and preferably from at least one of sulfur, carbon disulfide, sodium sulfide, and sodium hydrosulfide.

[0026] Here, the order in which the oil-soluble molybdenum source, the solvent, the coal powder, and the optional sulfur source are mixed is not particularly limited, as long as the oil-soluble molybdenum source can be dispersed as much as possible and the materials can be made as homogeneous as possible. However, preferably, the method includes the step of first mixing the oil-soluble molybdenum source and the solvent, then mixing with the coal powder, and adding or not adding the sulfur source to obtain the catalyst oil-coal slurry. The inventors of the present invention have found in their research that the step of first mixing the oil-soluble molybdenum source and the solvent allows for more uniform dispersion of the oil-soluble molybdenum source in the catalyst oil-coal slurry, thereby obtaining a higher oil yield.

[0027] In the present invention, there are no particular limitations on the coal powder, and the coal powder may be coal from various sources. The inventors of the present invention have found that the method of the present invention can achieve a good conversion effect even for coal powder with a low vitrinite content, such as coal with a vitrinite content of 40-48% by weight (e.g., 42%, 44%, or 46% by weight). It should be understood that coal generally contains vitrinite, inertinite, and exinite. Vitrinite has a high oxygen content, a low carbon content, and a moderate hydrogen content. During hydroliquefaction, vitrinite is easier to liquefy than the other two, and therefore the vitrinite content can generally characterize the difficulty of coal liquefaction. Generally, the higher the vitrinite content in coal powder, the easier it is to liquefy. In the prior art, it is generally desirable to use coal powder with a higher vitrinite content. The method of the present invention can achieve a good conversion effect not only for coal powder with a higher vitrinite content, but also for coal powder with a lower vitrinite content (e.g., 40-48% by weight vitrinite content), which is difficult to convert using prior art.

[0028] In a second aspect, the present invention comprises an oil-soluble molybdenum source, a solvent, coal powder, and an optional sulfur source. or A catalyst oil-coal slurry prepared by the method described in the first embodiment is provided. In this embodiment, the amount and type of each raw material are as described above and will not be repeated here.

[0029] In a third aspect, the present invention relates to a process of subjecting the catalyst oil-coal slurry described in the second aspect to direct coal liquefaction; or A process of subjecting coal powder to direct coal liquefaction in the presence of a solvent, an oil-soluble molybdenum source, and an optional sulfur source; The present invention provides a method for the direct liquefaction of coal, including the following. In this embodiment, the quantities and types of each raw material are as described above and will not be repeated here.

[0030] According to the present invention, when direct coal liquefaction is carried out, the direct coal liquefaction conditions can be those commonly used in the art, such as the direct coal liquefaction conditions disclosed in CN104893751A and CN100381540C. In one embodiment, the conditions for direct coal liquefaction include a pressure of 18 to 22 MPa (e.g., 20 MPa), a temperature of 435 to 475°C (e.g., 450°C or 460°C), and a reaction time of 0.5 to 1.5 hours (e.g., 1 hour). Direct coal liquefaction is generally carried out in the presence of hydrogen, the amount of which brings the pressure within the above range.

[0031] In a fourth aspect, the present invention provides the use of the catalyst oil-coal slurry described in the second aspect, or the method described in the first aspect, in direct coal liquefaction.

[0032] According to a particularly preferred embodiment of the present invention, A process to obtain a catalyst oil-coal slurry by thoroughly mixing liquid molybdenum dialkyldithiocarbamate with a solvent, stirring them uniformly, then adding coal powder to the mixture, adding sulfur, thoroughly mixing, and stirring them uniformly, wherein the amount of molybdenum element in the oil-soluble molybdenum source is 0.24 to 0.25 parts by weight per 100 parts by weight of coal powder, the amount of the solvent is 125 to 140 parts by weight, and the amount of sulfur is added such that the molar ratio of sulfur to molybdenum in the catalyst oil-coal slurry is 2.25 to 2.35; The process involves adding a catalyst oil-coal slurry to a reactor, adding hydrogen, setting the reaction pressure to 19-20 MPa, the reaction temperature to 455-460°C, and the reaction time to 1-1.3 hours; Following this method, a catalyst oil-coal slurry is prepared, and the coal is directly liquefied.

[0033] The present invention will be described in detail by the following examples. The coal powder in Examples 1 to 11 is Shendong coal, and more than 80% of it has a particle size of less than 200 mesh.

[0034] [Table 1]

[0035] In Table 1, the meanings of the symbols are as follows:

[0036] Industrial analysis section: Mad refers to the moisture content on an air-dry basis. Ad refers to the ash on a dry basis. Vdaf refers to the volatile matter on a dry, ash-free basis. Determined according to the methods in GB / T211-2017 and GB / T212-2008.

[0037] Elemental analysis section: FC daf refers to fixed carbon on a dry, ashless base. C, H, O, N, and S refer to the content of each element, respectively. Determined according to the methods in GB / T214-2007, GB / T476-2008, and GB / T19227-2008.

[0038] Sections of the petrological analysis described: Vitrinite refers to the vitrinite content. Inertinite refers to the inertinite content. Ecdinite refers to the ecdinite content. Measured according to the method in GB / T8899-2013.

[0039] The solvents used in Examples 1 to 11 were self-generated circulating solvents from the direct liquefaction of coal, and their main properties are shown in Table 2.

[0040] [Table 2]

[0041] <Example 1> Description of the method for preparing a catalyst oil-coal slurry provided by the present invention. Liquid molybdenum dialkyldithiophosphate (molybdenum content of 10.45% by weight, with 13 carbon atoms in the alkyl carbon chain) and a solvent were thoroughly mixed and uniformly stirred, then coal powder was added to the mixture, sulfur was added, and then the mixture was thoroughly mixed and uniformly stirred to obtain a catalyst oil-coal slurry. Here, per 100 parts by weight of coal powder, the amount of molybdenum element from the oil-soluble molybdenum source was 0.22 parts by weight, the amount of the solvent was 150 parts by weight, and sulfur was added in such an amount that the molar ratio of sulfur element to molybdenum element in the catalyst oil-coal slurry was 2.2.

[0042] <Example 2> Description of the method for preparing a catalyst oil-coal slurry provided by the present invention. Liquid molybdenum dialkyldithiocarbamate (molybdenum content of 10.45% by weight, with 13 carbon atoms in the alkyl carbon chain) and a solvent were thoroughly mixed and uniformly stirred, then coal powder was added to the mixture, carbon disulfide was added, and the mixture was thoroughly mixed and uniformly stirred to obtain a catalyst oil-coal slurry. Here, per 100 parts by weight of coal powder, the amount of molybdenum element from the oil-soluble molybdenum source was 0.2 parts by weight, the amount of the solvent was 120 parts by weight, and sulfur was added in such an amount that the molar ratio of sulfur element to molybdenum element in the catalyst oil-coal slurry was 2.5.

[0043] <Example 3> Description of the method for preparing a catalyst oil-coal slurry provided by the present invention. Liquid molybdenum dialkyldithiocarbamate (molybdenum content of 9.86% by weight, with 13 carbon atoms in the alkyl carbon chain) and a solvent were thoroughly mixed and uniformly stirred, then coal powder was added to the mixture, sulfur was added, and the mixture was thoroughly mixed and uniformly stirred to obtain a catalyst oil-coal slurry. Here, per 100 parts by weight of coal powder, the amount of molybdenum element from the oil-soluble molybdenum source was 0.25 parts by weight, the amount of the solvent was 130 parts by weight, and sulfur was added in such an amount that the molar ratio of sulfur element to molybdenum element in the catalyst oil-coal slurry was 2.3.

[0044] <Example 4> Description of the method for preparing a catalyst oil-coal slurry provided by the present invention. The catalyst oil-coal slurry was prepared according to the method of Example 3, but the difference was that no sulfur source was added.

[0045] <Example 5> The catalyst oil-coal slurry was prepared according to the method of Example 3, with the difference being that liquid molybdenum dialkyldithiocarbamate was replaced with hexacarbonylmolybdenum powder.

[0046] <Example 6> The catalyst oil-coal slurry was prepared according to the method of Example 3, but with the difference being that liquid molybdenum dialkyldithiocarbamate was replaced with molybdenum naphthenate powder.

[0047] <Example 7> The catalyst oil-coal slurry was prepared according to the method of Example 3, but with the difference being that the amount of molybdenum element from the oil-soluble molybdenum source was 0.1 parts by weight per 100 parts by weight of coal powder, the amount of solvent was 100 parts by weight, and sulfur was added in an amount such that the molar ratio of sulfur element to molybdenum element in the catalyst oil-coal slurry was 2.

[0048] <Example 8> The catalyst oil-coal slurry was prepared according to the method of Example 3, but with the difference being that, per 100 parts by weight of coal powder, the amount of molybdenum element from the oil-soluble molybdenum source was 0.3 parts by weight, the amount of solvent was 190 parts by weight, and sulfur was added in an amount such that the molar ratio of sulfur element to molybdenum element in the catalyst oil-coal slurry was 2.8.

[0049] <Example 9> The catalyst oil-coal slurry was prepared according to the method of Example 3, but with the difference being that the liquid molybdenum dialkyldithiocarbamate was replaced with molybdenum dialkyldithiocarbamate powder (the number of carbon atoms in the alkyl carbon chain was 4).

[0050] <Example 10> The catalyst oil-coal slurry was prepared according to the method of Example 3, but the difference was that the liquid molybdenum dialkyldithiocarbamate, solvent, coal powder, and sulfur were mixed simultaneously.

[0051] <Example 11> The catalyst oil-coal slurry was prepared according to the method of Example 3, but with the difference being that liquid molybdenum dialkyldithiocarbamate was replaced with molybdenum butyrate powder.

[0052] <Example 12> The catalyst oil-coal slurry was prepared according to the method of Example 3, but the solvent was tetrahydronaphthalene (its ρ 20 It is 0.9659 g·cm -3 The kinematic viscosity at 40°C is 1.8 mm³. 2 The difference was that it was replaced by (where the value was / s and the molar ratio of H to C was 1.2).

[0053] <Comparative Example 1> The difference in Example 3 was that the liquid molybdenum dialkyldithiocarbamate was replaced with molybdenum trioxide powder (non-oil soluble), following the method described in Example 3. The results are shown in Table 1.

[0054] <Comparative Example 2> The difference was that, following the method in Example 3, liquid molybdenum dialkyldithiocarbamate was replaced with molybdenum disulfide powder (non-oil soluble). The results are shown in Table 1.

[0055] <Comparative Example 3> The difference was that, following the method in Example 3, liquid molybdenum dialkyldithiocarbamate was replaced with ammonium heptamolybdate powder (non-oil soluble). The results are shown in Table 1.

[0056] <Comparative Example 4> 4.67 g of iron-based catalyst (containing 3.97 g of coal powder) was thoroughly mixed with 24.03 g of coal powder, 42 g of solvent, and 0.32 g of sulfur, and uniformly stirred to obtain an iron-based catalyst oil-coal slurry. Specifically, the amount of iron element was 1 part by weight and the amount of solvent was 150 parts by weight per 100 parts by weight of coal powder.

[0057] Here, the method for preparing the iron-based catalyst involved using Shinto coal as the raw material, with over 80% having a particle size of less than 200 mesh, the solvent oil being self-generated circulating solvent oil from direct coal liquefaction, and the precipitant being ammonia water. 49.64 g of FeSO4·7H2O crystals were dissolved at room temperature with 446.44 g of deionized water to prepare a specific aqueous solution. The solution was thoroughly dissolved and uniformly stirred, and 158.864 g of coal powder was added to the solution and thoroughly stirred to obtain a water-coal slurry with a coal powder concentration of approximately 24.12%. 24.272 g of commercially available ammonia water with a concentration of 26% by weight was added to 330.58 g of deionized water to dilute ammonia water with a concentration of approximately 1.71%. The water-coal slurry and the above dilute ammonia water were subjected to a neutralization reaction with parallel flow (co-flow) and precipitation to produce an amorphous precipitate of divalent iron, which was uniformly supported on coal powder. The air flow rate was set to 1.456 L / min and the aeration time was set to 1 hour. While oxygen was being introduced, ammonia water was continuously added thereto by drop to ensure that the pH of the process was 7-7.5. The slurry was then centrifuged by a centrifuge, and the filtered cake was placed in a forced-air drying oven at 40°C and dried overnight. The resulting catalyst was crushed to less than 200 mesh for later use. The iron content in the catalyst was 6% by weight.

[0058] <Test Example 1> The same amounts of catalyst oil-coal slurry prepared in Examples 1-11 and Comparative Examples 1-4 were collected, and direct coal liquefaction was performed according to the following method: A catalyst oil-coal slurry was added to the reactor, hydrogen was added, the reaction pressure was set to 19 MPa, the reaction temperature to 455°C, and the reaction time to 1 hour.

[0059] After the reaction was completed, gas-phase products and liquid-solid products were obtained. The composition of the gas-phase products was determined by gas chromatography. The liquid-solid products were subjected to Soxhlet extraction in turn with n-hexane and tetrahydrofuran. The n-hexane soluble matter was defined as oil, and the tetrahydrofuran soluble matter was defined as asphaltene and preasphaltene. The residue of the tetrahydrofuran-insoluble matter after drying and then calcining in a muffler furnace at 815 °C for 6 hours was defined as residual ash (RA). The coal conversion rate (X), gas yield (G), hydrogen consumption (H), oil yield (O), and asphaltene (including preasphaltene and asphaltene, A) yield were calculated according to the following formulas: X = 1 - (TI - RA) / F daf A = (HI - TI) / F daf H = (H0 - H1) / F daf G = (G1 - H1) / F daf O = X + H - G - W - A Here, F daf : mass of coal on anhydrous and ash-free basis, g;[[ID=--]] H0: mass of hydrogen filled in the reactor before the reaction, g; H1: mass of hydrogen remaining in the reactor after the reaction, g; G1: mass of gas in the reactor after the reaction, g; HI: mass of n-hexane-insoluble matter, g; TI: mass of tetrahydrofuran-insoluble matter, g; RA: mass of residue of tetrahydrofuran-insoluble matter after calcination, g; H: hydrogen consumption; G: gas yield; W: water yield, mass of water calculated by subtracting the oxygen element contained in the gas products CO and CO2 from the oxygen element in coal / F daf ; A: asphaltene yield, (mass of n-hexane-insoluble matter - mass of tetrahydrofuran-insoluble matter) / F daf ; O: Oil yield.

[0060] The coal conversion rate and oil yield are shown in Table 3.

[0061] [Table 3]

[0062] From the results in Table 3, it can be seen that by using Examples 1-12 of the present invention, higher conversion rates and higher oil yields can be obtained, and the oil yield can be increased by approximately 10 percentage points compared to Comparative Examples 1-4. Furthermore, the molybdenum dialkyldithiocarbamate and molybdenum dialkyldithiophosphate used in Examples 1-4 are inexpensive and can further reduce production costs.

[0063] Furthermore, the Shinto coal used above is a type of coal with a low vitrinite content that is difficult to liquefy. By using the technical solution of the present invention, a better conversion effect can be achieved for Shinto coal, which is difficult to liquefy, and an even better conversion effect can be achieved when applied to other types of coal that have a higher vitrinite content and are easier to liquefy.

[0064] While preferred embodiments of the present invention have been described in detail, the present invention is not limited thereto. Within the scope of the technical idea of ​​the present invention, various simple modifications can be made to the technical solutions of the present invention, including combining various technical features in any other suitable manner. These simple modifications and combinations should also be considered as part of the disclosures of the present invention and all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a catalyst oil-coal slurry, A method characterized by comprising the step of mixing an oil-soluble molybdenum source, a solvent, coal powder, and a sulfur source to obtain the catalyst oil-coal slurry, The oil-soluble molybdenum source is liquid molybdenum dialkyldithiocarbamate. The amount of the sulfur source is such that the molar ratio of sulfur to molybdenum in the catalyst oil-coal slurry is 2.2 to 2.

5. method.

2. The method according to claim 1, wherein the amount of molybdenum element in the oil-soluble molybdenum source is 0.005 to 1 part by weight per 100 parts by weight of coal powder.

3. The method according to claim 2, wherein the amount of molybdenum element in the oil-soluble molybdenum source is 0.1 to 0.3 parts by weight per 100 parts by weight of coal powder.

4. The method according to claim 3, wherein the amount of molybdenum element in the oil-soluble molybdenum source is 0.2 to 0.25 parts by weight per 100 parts by weight of coal powder.

5. The amount of the solvent is 80 to 220 parts by weight per 100 parts by weight of coal powder. and / or, The solvent is a hydrogen-donating solvent, and the amount of the hydrogen-donating solvent is 0.98 g / cm³. －３ Lower ρ ２０ , 5mm ２ The method according to claim 1, having a kinematic viscosity at 40°C lower than / s, and a molar ratio of H to C higher than 0.

25.

6. The method according to claim 5, wherein the amount of the solvent is 100 to 190 parts by weight per 100 parts by weight of coal powder.

7. The method according to claim 6, wherein the amount of the solvent is 120 to 150 parts by weight per 100 parts by weight of coal powder.

8. The method according to claim 1, wherein the sulfur source is selected from at least one of elemental sulfur, inorganic sulfur, and organic sulfur.

9. The method according to claim 8, wherein the sulfur source is selected from at least one of sulfur, carbon disulfide, sodium sulfide, and sodium hydrosulfide.

10. The method according to any one of claims 1 to 9, comprising the steps of first mixing the oil-soluble molybdenum source and the solvent, then mixing with the coal powder, and adding the sulfur source to obtain the catalyst oil-coal slurry.

11. A catalyst oil-coal slurry characterized by comprising an oil-soluble molybdenum source, a solvent, coal powder, and a sulfur source, The oil-soluble molybdenum source is liquid molybdenum dialkyldithiocarbamate. The amount of the sulfur source is such that the molar ratio of sulfur to molybdenum in the catalyst oil-coal slurry is 2.2 to 2.

5. Catalyst oil - coal slurry.

12. The catalyst oil-coal slurry according to claim 11, wherein the amount of molybdenum element in the oil-soluble molybdenum source is 0.005 to 1 part by weight per 100 parts by weight of coal powder.

13. The catalyst oil-coal slurry according to claim 12, wherein the amount of molybdenum element in the oil-soluble molybdenum source is 0.1 to 0.3 parts by weight per 100 parts by weight of coal powder.

14. The catalyst oil-coal slurry according to claim 13, wherein the amount of molybdenum element in the oil-soluble molybdenum source is 0.2 to 0.25 parts by weight per 100 parts by weight of coal powder.

15. A step of subjecting the catalyst oil-coal slurry according to claim 11 to direct coal liquefaction; or A process of subjecting coal powder to direct coal liquefaction in the presence of a solvent, an oil-soluble molybdenum source, and a sulfur source; A method for the direct liquefaction of coal, characterized by comprising: The oil-soluble molybdenum source is liquid molybdenum dialkyldithiocarbamate. The amount of the sulfur source is such that the molar ratio of sulfur to molybdenum in the catalyst oil-coal slurry is 2.2 to 2.

5. method.

16. The method according to claim 15, wherein the conditions for direct coal liquefaction include a pressure of 18 to 22 MPa, a temperature of 435 to 475°C, and a time of 0.5 to 1.5 hours.

17. Use of the catalyst oil-coal slurry according to claim 11, or the method according to any one of claims 1 to 9, in direct coal liquefaction.

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