JP3287684B2 - Coal liquefaction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for liquefying coal, and more particularly to a method for efficiently hydrogenating coal in the presence of a catalyst.
The present invention relates to a method for liquefying coal obtained by separating oil components such as light oil, medium oil, and heavy oil from a hydrogenated product by a separation operation such as distillation.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for the development of liquid fuels that can replace petroleum due to resource and energy situations. In particular, since coal has abundant reserves, it is an important issue to establish a technology to efficiently liquefy coal and obtain liquid fuel. For this reason, various coal liquefaction methods have been proposed in the past, but a typical coal liquefaction method is to mix dried and pulverized coal with a solvent to form a slurry-like mixture, and to form a hydrogen gas under high temperature and pressure. Is added to cause a hydrogenation reaction to liquefy.

[0003] When a hydrogenation reaction (liquefaction reaction) of such coal is caused, a catalyst component contained in coal may be used without adding a catalyst depending on the kind of raw material coal. In order to increase the efficiency of the addition reaction, a method is used in which a catalyst is added to the slurry-like mixture and the mixture is subjected to a hydrogenation reaction, and the coal is hydrogenated in the presence of the catalyst and the solvent.

A catalyst for improving the efficiency of this hydrogenation reaction,
That is, as a catalyst for accelerating coal liquefaction (hereinafter referred to as a catalyst for coal liquefaction), conventionally, various molybdenum-based catalysts, zinc chloride, tin chloride or iron sulfide, iron sulfate, iron oxide, red mud, iron ore, etc. Are known. However, none of these conventional catalysts can satisfy the conditions such as excellent economy and activity required as a catalyst for coal liquefaction, and have disadvantages such as insufficient economy or activity. In other words, the catalyst for coal liquefaction needs to be active (enhancing the efficiency of the hydrogenation reaction), be cheap and easy to obtain from the economical point of view of coal liquefaction, and have problems in coal liquefaction operation. It is necessary that the above-mentioned conventional catalysts are expensive, have insufficient activity,
Alternatively, there are problems such as causing corrosion damage to the coal liquefaction apparatus.

[0005] When these problems are classified by catalyst, molybdenum-based catalysts are expensive and have resource problems, and chloride-based catalysts such as zinc chloride are liable to cause corrosion of the apparatus. In addition, catalysts such as red mud and iron ore are inexpensive, but have a problem of insufficient activity.

[0006] Among these catalysts, iron ore has insufficient activity, but has an advantage that it is particularly inexpensive and easily available, so that it is often used as a catalyst for coal liquefaction. In this case, iron ore mechanically pulverized to reduce the particle size in order to enhance the activity of the catalyst (crushed iron ore catalyst) is added to the slurry-like mixture as a coal liquefaction catalyst,
Then, it is subjected to a hydrogenation reaction, and a method of hydrogenating coal in the presence of a crushed iron ore catalyst and a solvent is employed. This is because, by using a pulverized iron ore catalyst having a small particle size, the dispersibility of the pulverized iron ore catalyst in a solvent coexisting in the slurry-like mixture is increased, thereby increasing the contact efficiency with coal, and thereby the pulverization. The aim is to increase the activity of iron ore catalysts.

The iron ore is mechanically pulverized by a dry pulverization method of pulverizing in an air or an inert gas using a pulverizer such as a ball mill or a tower mill, or in the presence of an alcohol or a petroleum-based general solvent. This is performed by a wet pulverization method in which pulverization is performed.

[0008]

However, in the coal liquefaction method using the above-mentioned conventional pulverized iron ore catalyst as a coal liquefaction catalyst, remarkable agglomeration of the pulverized iron ore catalyst occurs in a solvent, and the dispersion is insufficient. As the contact efficiency with coal decreases, the activity of the crushed iron ore catalyst decreases, and its catalytic effect is not sufficiently exhibited. Therefore, the liquefaction reaction efficiency decreases, and the yield of oil component is low. There is a problem that it is insufficient.

The present invention has been made in view of such circumstances, and has as its object to solve the problems of the conventional coal liquefaction method using the above-mentioned crushed iron ore catalyst as a coal liquefaction catalyst. Excellent in the dispersibility of the catalyst in the solvent, the contact efficiency between the catalyst and the coal can be increased, whereby the catalytic activity is enhanced and the catalytic effect is sufficiently exhibited, and therefore the liquefaction reaction efficiency can be improved, It is an object of the present invention to provide a coal liquefaction method which can improve the yield of oil.

[0010]

In order to achieve the above object, a method for liquefying coal according to the present invention has the following configuration. That is, the method for liquefying coal according to claim 1 is a method for liquefying coal including a hydrogenation step of hydrogenating pulverized coal in the presence of a solvent and a catalyst. Average particle size: 10μ
A coal liquefaction method characterized by using ground iron ore of m or less.

The method for liquefying coal according to claim 2 comprises a hydrogenation step of hydrogenating the pulverized coal in the presence of a solvent and a catalyst.
A solvent separation step in which a solvent is separated by a separation operation from a hydrogenation product obtained in the hydrogenation step, a part of the solvent obtained in the solvent separation step is introduced into a grinder, and iron ore is removed in the solvent. An coal ore liquefaction method comprising mechanically pulverizing an iron ore into a pulverized iron ore having an average particle diameter of 10 μm or less, and using the pulverized iron ore as the catalyst.

[0012] The method for liquefying coal according to claim 3 is characterized in that:
A slurry preparation step of obtaining a slurry mixture in which a solvent and a catalyst coexist, a hydrogenation step of heating the slurry mixture and hydrogenating coal, and separating an oil component from a hydrogenation product obtained in the hydrogenation step by a separation operation. An oil separation step obtained by separation, a solvent circulating supply step of circulating and supplying a part of the solvent that is a part of the oil obtained by the oil separation step to the slurry preparation step, and a part of the solvent obtained by the oil separation step Is introduced into a pulverizer, and the iron ore is mechanically pulverized in the solvent to obtain a pulverized iron ore having an average particle diameter of 10 μm or less. This is a characteristic coal liquefaction method.

Further, in the method for liquefying coal according to claim 4, the amount of the catalyst is 0.1% to the weight of coal in terms of anhydrous ashless content.
The method for liquefying coal according to claim 1, wherein the amount is from 10 to 10% by weight. The method for liquefying coal according to claim 5 is the method for liquefying coal according to claims 1, 2, 3 or 4, wherein the raw iron ore of the pulverized iron ore is a natural pyrite ore.

[0014]

The present invention has been studied to find a catalyst for coal liquefaction that can improve the yield of oil. As a result, iron ore that has been mechanically pulverized in a liquefied coal liquefaction solvent has low dispersibility in the solvent. The present invention has been newly completed based on this finding, which is excellent in that the catalyst effect can be sufficiently exhibited, and therefore, the yield of oil can be improved.

That is, iron ore mechanically pulverized by a dry pulverization method or a wet pulverization method in which pulverization is performed in the presence of an alcohol or a petroleum-based general solvent (the conventional pulverized iron ore catalyst) is used as a catalyst for coal liquefaction. When used, as described above, remarkable agglomeration of the catalyst occurs in the solvent, and the dispersion of the catalyst becomes insufficient, so that the contact efficiency with coal is reduced, and thus the catalytic effect is not sufficiently exhibited. When iron ore is mechanically pulverized in a coal liquefaction circulation solvent (that is, ground iron ore mechanically pulverized in a coal liquefaction circulation solvent) as a catalyst for coal liquefaction, coagulation of the catalyst in the solvent is caused. Is less likely to occur, and the catalyst dispersibility is excellent, so that the contact efficiency between the catalyst and the coal can be increased, and therefore the catalytic activity is enhanced and the catalytic effect is sufficiently exhibited, and as a result, the liquefaction reaction efficiency is improved. I , The pulling was obtained new findings that can improve the oil yield.

The method for liquefying coal according to the present invention is based on the above findings. The method for liquefying coal includes the step of hydrogenating pulverized coal in the presence of a solvent and a catalyst. As the catalyst, a pulverized iron ore having an average particle size of 10 μm or less mechanically pulverized in a coal liquefaction circulation solvent is used (the method of liquefying coal according to claim 1). Therefore, the catalyst (pulverized iron ore catalyst) in the solvent is excellent in dispersibility, and the contact efficiency between the catalyst and the coal can be increased, whereby the catalytic activity is enhanced and the catalytic effect is sufficiently exerted. Thus, the liquefaction reaction efficiency can be improved, and the yield of oil can be improved.

At this time, the reason why the average particle diameter of the pulverized iron ore (pulverized iron ore catalyst) mechanically pulverized in the coal liquefaction circulation solvent is not more than 10 μm is that if it exceeds 10 μm, it is used as a catalyst for coal liquefaction. However, even if the dispersibility is excellent, the contact efficiency between the catalyst and the coal is low because the effective surface area of the catalyst (the outer surface area of the catalyst particles per catalyst weight) is small,
This is because the catalyst activity becomes insufficient. In order to increase the effective surface area of such a catalyst and to increase the catalytic activity, the average particle diameter is preferably as small as 10 μm or less, and from such a point, it is desirable that the average particle diameter be 5 μm or less, particularly 1 μm or less. Is desirable.

Such crushed iron ore supplies iron ore to a crusher such as a ball mill or a tower mill and introduces a part of a liquefied coal liquefaction solvent used in a coal liquefaction process. It can be obtained by a method in which iron ore is pulverized while the stone is immersed.

Here, the coal liquefaction circulation solvent is used as a solvent in a slurry preparation step (a step of obtaining a slurry-like mixture in which coal, a solvent and a catalyst coexist), and a coal hydrogenation step (hydrogenation reaction is carried out). In the step of raising and liquefying the coal), the product (hydrogenated product) is separated from the product (hydrogenated product) by a solvent separation step or an oil separation step (separation operation such as distillation from the hydrogenated product).
Step of separating solvent or step of separating oil)
After being separated as a solvent in, is circulated and supplied to the slurry preparation process and used as a solvent, and thereafter, this is repeated,
A solvent circulating between the slurry preparation step and the solvent separation step or the oil separation step (first coal liquefaction circulation solvent), and separated as a solvent in the solvent separation step or the oil separation step, and, if necessary, a slurry adjustment step Refers to a solvent (second coal liquefaction circulating solvent) that is circulated and supplied to other processes.

Therefore, most of the coal liquefaction circulating solvent is circulated and supplied to the slurry preparation step and used as a solvent. In the present invention, a part of the coal liquefaction circulating solvent is introduced into a pulverizer. It is used for grinding iron ore in a coal liquefaction circulation solvent. That is, while the solvent obtained by the separation in the solvent separation step or the oil separation step is circulated and supplied to the slurry preparation step as a coal liquefaction circulation solvent, a part of the solvent is pulverized into iron ore in the coal liquefaction circulation solvent. To be supplied to a crusher for use.

The coal liquefaction circulating solvent supplied to the first slurry preparation step at the start of the coal liquefaction operation (the slurry preparation step before the start of the hydrogenation step) varies depending on the coal liquefaction process and reaction conditions. Generally 180-450
A coal-based solvent selected from fractions in the boiling range of ° C is used. This solvent circulates between the slurry preparation step and the solvent separation step (or oil separation step) as a coal liquefaction circulating solvent, but its properties change with the coal liquefaction operation time, and generally remain constant for several tens of hours. To show the properties.

The amount of the liquefied coal circulating solvent is usually 1 to 3 times the amount of the supplied coal, and thus the amount of the solvent used is enormous. Therefore, among the solvent separation step and the oil separation step, an oil separation step is adopted, and in the oil liquefaction method of obtaining oil (light oil, medium oil, heavy oil) as a product in the oil separation step, Part of the oil component is used as a coal liquefaction circulation solvent, and in particular, part of the medium oil and / or heavy oil is often used as the coal liquefaction circulation solvent.

By the way, the conventional pulverized iron ore catalyst causes remarkable agglomeration in a solvent, but pulverized iron ore mechanically pulverized in a liquefied coal circulating solvent (pulverized iron ore catalyst according to the present invention) is dissolved in a solvent. The reason why the aggregation is unlikely to occur is considered as follows.

That is, in the conventional crushed iron ore catalyst,
Since its surface (fracture surface newly generated by mechanical pulverization) is extremely unstable, and has a small particle size and is in a state where particles are easily aggregated, remarkable aggregation occurs in a solvent. On the other hand, in the crushed iron ore catalyst according to the present invention, although the particle diameter is smaller than or equal to that of the conventional crushed iron ore catalyst, the particle surface (fracture surface newly generated by mechanical pulverization) has Since the coal liquefaction circulation solvent is attached and the coal liquefaction circulation solvent contains many polar components, many polar components are adsorbed on the surface of fresh particles immediately after pulverization, Prevent aggregation,
Therefore, it is considered that aggregation does not easily occur even in a solvent.

The crushed iron ore catalyst according to the present invention hardly causes agglomeration in a solvent and is excellent in dispersibility, so that the catalytic activity is enhanced. However, the crushed iron ore catalyst is also excellent in affinity for coal. Therefore, there is an advantage that the utilization efficiency of the catalyst is remarkably improved, and thereby the catalyst activity is enhanced.
Here, the reason for the excellent affinity with coal is considered as follows.

That is, since the coal liquefaction circulating solvent exhibits almost constant properties as the repetition of circulation proceeds as described above, the coal liquefaction circulating solvent having this constant property is the solvent (coal liquefaction) generated by the coal liquefaction reaction. Solvent) and the components are close to each other, and therefore have excellent affinity with coal. It is considered that the crushed iron ore catalyst according to the present invention has such a coal liquefaction circulating solvent adhered to its surface, and therefore has excellent affinity with coal.

Next, in the coal liquefaction method according to the present invention,
The method for liquefying coal according to claims 2 and 3 will be described below.

[0028] In the method for liquefying coal according to claim 2, a hydrogenation step of hydrogenating the pulverized coal in the presence of a solvent and a catalyst,
A solvent separation step in which a solvent is separated by a separation operation from a hydrogenation product obtained in the hydrogenation step, a part of the solvent obtained in the solvent separation step is introduced into a grinder, and iron ore is removed in the solvent. An iron ore pulverizing step of mechanically pulverizing the iron ore into an average particle diameter of 10 μm or less into an iron ore is used, and the pulverized iron ore is used as the catalyst.

The coal liquefaction method according to the present invention is applied to a case where a solvent separation step is adopted as a separation step of a hydrogenated product, and a part of the solvent obtained by the solvent separation step is used. Is introduced into a pulverizer, and iron ore is mechanically pulverized in the solvent to obtain pulverized iron ore having an average particle diameter of 10 μm or less, and this is used as a catalyst. Here, the solvent introduced into the pulverizer is a coal liquefaction circulation solvent (second
(Coal liquefaction circulation solvent). Therefore, a mechanically pulverized iron ore having an average particle size of 10 μm or less in a coal liquefaction circulation solvent is used as a catalyst. Therefore, the same operation and effects as those of the coal liquefaction method according to claim 1 can be obtained.

[0030] The method for liquefying coal according to claim 3 comprises:
A slurry preparation step of obtaining a slurry mixture in which a solvent and a catalyst coexist, a hydrogenation step of heating the slurry mixture and hydrogenating coal, and separating an oil component from a hydrogenation product obtained in the hydrogenation step by a separation operation. An oil separation step obtained by separation, a solvent circulating supply step of circulating and supplying a part of the solvent that is a part of the oil obtained by the oil separation step to the slurry preparation step, and a part of the solvent obtained by the oil separation step Is introduced into a pulverizer, and the iron ore is mechanically pulverized in the solvent to obtain a pulverized iron ore having an average particle diameter of 10 μm or less. It is a feature.

In the method for liquefying coal according to the third aspect, an oil separation step is employed as a separation step of a hydrogenated product to obtain an oil (light oil, medium oil, or heavy oil) as a product. It is applied, and a part of the solvent (medium oil and / or heavy oil) which is a part of this oil is circulated and supplied to the slurry preparation step, and is used as a coal liquefaction circulation solvent. A part is introduced into a pulverizer, and iron ore is mechanically pulverized in the solvent to obtain pulverized iron ore having an average particle diameter of 10 μm or less, which is used as a catalyst. here,
The solvent introduced into the pulverizer corresponds to a coal liquefaction circulation solvent (second coal liquefaction circulation solvent). Therefore, a mechanically pulverized iron ore having an average particle size of 10 μm or less in a coal liquefaction circulation solvent is used as a catalyst. Therefore, the same operation and effects as those of the coal liquefaction method according to claim 1 can be obtained.

In the coal liquefaction method according to the present invention, the amount of the catalyst used is desirably 0.1 to 10% by weight based on the weight of coal in terms of anhydrous ashless content. If the amount is less than 0.1 wt%, the yield of oil tends to decrease. If the amount exceeds 10 wt%, not only the amount of the catalyst used becomes enormous, but also the wear and tear of the device tends to occur easily.
Further, from the viewpoint of the cost of the catalyst including pulverization and the effect of improving the oil yield, it is desirable to set the amount to 0.5 to 8% by weight.

The raw iron ore of the pulverized iron ore used as a catalyst is not limited as long as it has a coal liquefaction catalytic function, and examples thereof include natural pyrite ore (pyrite), limonite, hematite, magnetite and the like. Can be mentioned. Among them, natural pyrite ore has features and advantages such as being rich in resources and not requiring sulfur as a promoter.

As the coal, subbituminous coal or bituminous coal can be used in addition to low-carbonized coal such as lignite (low-carbonized coal). These are usually used after being dried to a water content of 15% or less, and then pulverized to a particle size smaller than about 60 mesh, whereby coal liquefaction can be advantageously performed.

The operation of separating the solvent or oil in the solvent separation step and the oil separation step is not limited, and means such as distillation and filtration can be employed. In the case of distillation, distillation suitable for a desired object may be appropriately selected.

In addition to the pulverized iron ore catalyst according to the present invention, a sulfur compound such as elemental sulfur or hydrogen sulfide can be added as a co-catalyst, and the addition thereof can further promote the coal liquefaction reaction. In this case, the addition amount is 0.1 to 3 times the weight of iron in the crushed iron ore catalyst as the amount of sulfur.
The amount is preferably doubled, but may be small when the sulfur compound content in the coal is large.

[0037]

【Example】

Example 1 FIG. 1 shows a flow sheet of a coal liquefaction method according to Example 1. Embodiment 1 will be described below with reference to FIG. In the coal slurry preparation tank 1, the dried and pulverized coal, the coal liquefaction circulating solvent recovered from the distillation tower 6, and a part of the coal liquefaction circulating solvent are introduced into a pulverizer, and iron ore is removed in the solvent. A mechanically pulverized product having an average particle size of 10 μm or less (crushed iron ore catalyst) and sulfur (promoter) recovered from the desulfurization unit 5 are supplied and mixed to obtain a slurry-like mixture. .

The slurry mixture is transported to the preheater 2 by a slurry pump. During this time, hydrogen gas is added. Then, the mixture is introduced into a reactor 3 of a continuous stirring tank type, a flow tube type, a bubble column type, or the like, and the temperature is 380 to 480.
The liquefaction reaction is carried out at a temperature of 6 ° C. and a hydrogen pressure of 6 to 25 MPa for about 10 to 60 minutes. In the meantime, the raw coal is gradually lightened by being subjected to extraction and dissolution by a coal liquefaction circulating solvent, hydrogenation by a catalyst, hydrocracking reaction, and the like, and changes to a desired product.

After the completion of the liquefaction reaction, the obtained reaction mixture is introduced into the gas-liquid separator 4, where the gas components are separated and sent to the desulfurizer 5. Here, the sulfur is recovered, and the sulfur is fed back to the coal slurry preparation tank 1 and the other gas components are recovered as off-gas.

The liquid and solid components remaining in the gas-liquid separator 4 are sent to a distillation column 6, where light oil, medium oil and heavy oil are separated as products to obtain the medium oil and heavy oil. A part of the high quality oil is recovered as a coal liquefaction circulation solvent and circulated and supplied to the coal slurry preparation tank 1. On the other hand, a part of the medium oil and heavy oil (coal liquefaction circulation solvent) is introduced into a pulverizer, and iron ore is mechanically pulverized in the solvent. The coal is supplied to the slurry preparation tank 1 and the dried and pulverized coal is supplied to the coal slurry preparation tank 1.

The above operation was repeated. As a result, it was confirmed that the pulverized iron ore catalyst did not cause aggregation and was highly dispersed in the solvent in the slurry-like mixture. Therefore, it was confirmed that the catalyst activity was high and the catalyst effect was sufficiently exhibited.

(Example 2) An ultrafine mill (manufactured by Mitsubishi Heavy Industries, Ltd.) was used as a pulverizer, and 10 kg of pyrite ore (produced by Tasmania) was used in the pulverizer. 6 kg of coal liquefaction circulating solvent) is used, and pirite ore is pulverized in a brown coal liquefaction circulating solvent for 6 hours, average particle diameter: 0.5 μm
m of crushed iron ore (pyrite ore) was obtained.

Next, the above-mentioned crushed iron ore was added as a catalyst to Yaloon lignite, Australia, and a lignite liquefaction circulation solvent was further added.
A slurry-like mixture was obtained. At this time, the added amount of the crushed iron ore is expressed as iron atoms based on the weight of lignite in terms of anhydrous ashless content.
The amount was 3.0 wt%.

The above slurry-like mixture was introduced into an autoclave (internal volume: 5 liters), and hydrogen initial pressure: 9.0 MPa,
A hydrogenation reaction (liquefaction reaction) was performed under a reaction temperature of 450 ° C. and a reaction time of 60 minutes. Thereafter, the obtained reaction product (hydrogenated product) was separated, distilled, and oil was separated by boiling range to obtain. As a result, the yield of a liquid fraction (oil component) having a C ₅ to boiling point of 420 ° C. or lower was 44% by weight based on anhydrous ashless content (ratio to the weight of coal in terms of anhydrous ashless content).

For comparison, 10 kg of pyrite ore was dry-pulverized in an ultrafine mill for about 3 hours in a nitrogen stream,
Pulverized iron ore having an average particle diameter of 0.5 μm was obtained, and using this as a catalyst, coal liquefaction and distillation were carried out in the same steps as described above. As a result, the yield of the liquid fraction having a C ₅ to boiling point of 420 ° C. or less was 39 wt% based on anhydrous ashless content.

[0046]

According to the coal liquefaction method of the present invention,
Excellent dispersibility of the catalyst (crushed iron ore catalyst) in the solvent, and can increase the contact efficiency between the catalyst and the coal, thereby enhancing the catalytic activity and fully exerting the catalytic effect, and as a result, liquefaction The reaction efficiency can be improved, and thus the oil yield can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an outline of a coal liquefaction method according to a first embodiment.

[Explanation of symbols]

1-coal slurry preparation tank, 2-preheater, 3-reactor, 4
--Gas-liquid separator, 5--desulfurizer, 6--distillation tower.

──────────────────────────────────────────────────続 き Continuing from the front page (73) Patent holder 000105567 Cosmo Oil Co., Ltd. 1-1-1, Shibaura, Minato-ku, Tokyo (72) Inventor Takao Kaneko 2-2-12, Moridai, Atsugi-shi, Kanagawa (72) Inventor Toru Koyama 124-1-101 Minori, Kakogawa-cho, Kakogawa City, Hyogo Prefecture 1-35 -518 (56) References JP-A-6-100868 (JP, A) JP-A-6-99071 (JP, A) JP-A-60-88089 (JP, A) JP-A-61-86937 ( JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C10G 1/06 C10G 1/08

Claims (5)

(57) [Claims] 1. A coal liquefaction method comprising a hydrogenation step of hydrogenating pulverized coal in the presence of a solvent and a catalyst, wherein the catalyst has an average particle size mechanically pulverized in a coal liquefaction circulation solvent: A coal liquefaction method using crushed iron ore of 10 μm or less. 2. A hydrogenation step of hydrogenating pulverized coal in the presence of a solvent and a catalyst, a solvent separation step of separating a solvent from a hydrogenation product obtained in the hydrogenation step by a separation operation, Introducing a part of the solvent obtained in the solvent separation step into a pulverizer, and mechanically pulverizing the iron ore in the solvent to obtain a pulverized iron ore having an average particle diameter of 10 μm or less; A coal liquefaction method comprising using crushed iron ore as the catalyst. 3. A slurry preparation step for obtaining a slurry-like mixture in which coal, a solvent and a catalyst coexist, a hydrogenation step of heating the slurry-like mixture and hydrogenating coal, and a hydrogenation production obtained by the hydrogenation step Oil separating step obtained by separating oil from the product by a separating operation, a solvent circulating supply step of circulating and supplying a part of a solvent that is a part of the oil obtained by the oil separating step to the slurry preparation step, the oil separating step Introducing a part of the solvent obtained by the method into a pulverizer, and mechanically pulverizing the iron ore in the solvent to obtain a pulverized iron ore having an average particle diameter of 10 μm or less. Is used as the catalyst. 4. The coal liquefaction method according to claim 1, wherein the amount of the catalyst is 0.1 to 10% by weight based on the weight of the coal in terms of anhydrous ashless content. 5. The coal liquefaction method according to claim 1, wherein the raw iron ore of the ground iron ore is a natural pyrite ore.