AU673784B2 - Process of coal liquefaction - Google Patents

Description

P/00/011 28/1/91 Rogulation 3,2

AUSTRALIA

PATENTS ACT 1990 COMPLETE

SPECIFICATION

FOR A STANDARD PATENT

ORIGINAL

0** 0 0.

09** 0.a *b TO BE COMPLETED BY APPLICANT Name of Applicant: NIPPON BROWN COAL LIQUEFACTION CO., LTD.

Actual Inventors: Takao KANEKO; Toru KOYAMA; Kazuharu TAZAWA; Koichi SATO; Jun IMAI; and Eiichiro MAKINO Address for Service: CALLINAN LAWRIE, 278 High Street, Kew, 3101, Victoria, Australia Invention Title: "PROCESS OF COAL LIQUEFACTION" The following statement is a full description of this invention, including the best method of performing it known to us:- -2- PROCESS OF COAL LIQUEFACTION BACKGROUND OF THE INVENTION 1. Field of the Invention: The present invention relates to a process of coal liquefaction, and more particularly, to a process of coal liquefaction including the step of hydrogenating coal in the presence of catalyst.

2. Description of the Prior Art: The recent resources and energy situation urgently requires the development of a liquid fuel as a substitute for petroleum. One possibility of meeting this requirement is coal liquefaction in view of abundant coal reserves.

There have been proposed a variety of processes for coal liquefaction. A typical one of them consists of mixing dry pulverized coal with a solvent to give a slurry mixture and performing hydrogenation at a high temperature under a S high pressure.

Such hydrogenation (liquefaction) of coal may require no catalyst, in which case a certain component in coal functions as a catalyst. However, it is standard procedure to add a catalyst to the slurry mixture to promote hydrogenation. Thus it follows that coal hydrogenation is carried out in the presence of solvent and catalyst.

There have been known several catalysts to promote hydrogenation or to promote coal liquefaction. They include molybdenum compounds, S chlorides (such as zinc chloride and tin chloride), and iron compounds (such as iron sulfide, iron sulfate, iron oxide, iron hydroxide, red mud, and iron ore).

28/2/96LPCOAL.SPE,M2 -3- However, they are not satisfactory for coal liquefaction and involve several problems.

Catalysts for coal liquefaction should be active enough to promote hydrogenation. In addition, they should be cheap and readily available for economical coal liquefaction, and they should not cause trouble during operation. Unfortunately, molybdenum compounds are very expensive and limited in supply; chlorides tend to cause corrosion to the apparatus; and iron compounds are poor in catalytic activity although inexpensive.

Despite the above-mentioned problems, the iron-based catalyst, especially iron ore, is in general use for coal liquefaction because of its low price and abundant supply.

Iron ore as a catalyst for coal liquefaction is used in the form of mechanically pulverized fine particles so as to improve its catalyst activity. The i: pulverized iron ore is added to the above-mentioned slurry mixture for hydrogenation. The object of making iron ore into fine particles is to improve its dispersibility into the slurry and to increase the area of contact with coal (which is a requisite for high catalytic activity, The mechanical pulverizing of iron ore may be accomplished by using a grinder (such as ball mill and tower mill) in the air or an inert gas (dry process) or in the presence of alcohol or petroleum solvent (wet process).

*o When used as a catalyst in the conventional process for coal o liquefaction, the pulverized iron ore suffers a disadvantage of aggregating in the solvent, resulting in poor dispersion and insufficient contact with coal. This 2.27W96LPCOAL.SPE,3 i i -4leads to a low catalytic activity, a low liquefaction rate, and a low oil yield.

In addition, the pulverized iron ore should be used in a large amount because of its inherently inefficient catalytic activity. For example, the amount of pyrite is 5-10 wt% of coal on dry ash-free basis. (Pyrite is commonly used because of its comparatively high catalytic activity). The high content of pulverized iron ore in the slurry mixture is a cause of erosion to the piping, pumps, valves, etc. Pulverizing a large amount of iron ore costs much.

Any attempt to reduce the amount of pulverized iron ore to solve the above-mentioned problem ends up with an insufficient catalytic activity, a low liquefaction efficiency, and a low oil yield. Thus there is a demand for a process for coal liquefaction which affords a high oil yield even when the catalyst is used in an amount small enough to avoid problems with erosion.

Of the above-mentioned iron-based catalysts, iron hydroxide has a ~comparatively high catalytic activity. It is available in the form of limonite 1 5 (mineral), amorphous iron hydroxide formed by neutralization and precipitation of a ferric salt, or (-iron oxyhydroxide (geothite) formed by neutralization and precipitation of a ferrous salt. However, these conventional catalysts based on ss iron hydroxide do not have a sufficiently high catalytic activity to make coal *0:6.0 liquefaction economically feasible. Thus there still is a demand for an economical process for coal liquefaction which affords a high oil yield with a S high catalytic activity.

SUMMARY OF THE INVENTION The present invention was completed in view of the foregoing. It is 2712/96LPCOAL.SPE,4 an object of the present invention to provide a process for coal liquefaction which is capable of producing oil in a higher yield with a higher catalytic activity than the conventional process which employs pulverized iron ore as the catalyst.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram showing the process of coal liquefaction pertaining to the present invention.

Fig. 2 is a graph showing the relationship between the amount of the catalyst and the yield of oil.

Fig. 3 is an X-ray diffraction pattern of Catalyst A pertaining to the invention of application No.

Fig. 4 is a graph showing the relationship between the average particle diameter of the catalyst and the yield of oil.

DETAILED DESCRIPTION OF THE INVENTION 915 The above-mentioned object is achieved by the process for coal liquefaction as defined below.

A process of coal liquefaction by hydrogenation of pulverized coal in 1 the presence of solvent and catalyst, wherein the catalyst is powdery iron ore having an average particle diameter not greater than 10 pm which has been i 2d mechanically pulverized in the recycled solvent for coal liquefaction.

A process of coal liquefaction including the steps of hydrogenating S pulverized coal in the presence of solvent and catalyst, separating the solvent from the hydrogenation product, introducing part of the separated solvent into a P 27/2//9LPCOAL.SPE,5

I

-6pulverizer, and pulverizing iron ore in the solvent into pulverized iron ore having an average particle diameter not greater than 10 um, wherein the pulverized iron ore is used as the catalyst.

A process of coal liquefaction including the steps of preparing a slurry mixture composed of coal, solvent, and catalyst, heating the slurry mixture for coal hydrogenation, separating oil fractions from the hydrogenation product, recycling part of the solvent (as part of the separated oil fractions) to the step of preparing a slurry mixture, introducing part of the solvent separated from the oil fractions into a pulverizer, pulverizing iron ore in the solvent into pulverized iron ore having an average particle diameter not greater than 10 Um, wherein the pulverized iron ore is used as the catalyst.

A process of coal liquefaction as described in the above paragraphs wherein the amount of the catalyst is 0.1-10 wt% of the amount of coal on dry ash-free basis.

*999** 1; A process of coal liquefaction as described in the above paragraphs wherein the raw material of the pulverized iron ore is natural pyrite.

A process of coal liquefaction as described above wherein coal, S: solvent, and catalyst coexist with sulfur (as a simple compound) or a sulfur oooo 9* compound.

2 The present invention resulted from researches on catalysts capable S of coal liquefaction in high yields. It turned out that iron ore mechanically o° pulverized in the recycled solvent for coal liquefaction is readily dispersible in the solvent, exhibits a high catalytic activity, and produces oil in high yields.

S~27I2V961PCOAL.SPil.6 -7- As mentioned above, coal liquefaction by the process of the present invention employs as the catalyst iron ore mechanically pulverized in the recycled solvent for coal liquefaction. Such pulverized iron ore is readily dispersible in the solvent with little tendency to aggregation, which leads to good contact with coal, high catalytic activity, high liquefaction efficiency, and high oil yields. This effect is not produced if iron ore is pulverized by dry process or by wet process in alcohol or common petroleum solvent.

The first claim of the present invention covers a process of coal liquefaction by hydrogenation of pulverized coal in the presence of solvent and catalyst, wherein the catalyst is powdery iron ore having an average particle diameter not greater than 10 pm which has been mechanically pulverized in the recycled solvent for coal liquefaction. Such powdery iron ore readily disperses in the solvent, easily comes into contact with coal, and exhibits a high catalytic activity, which leads to higher liquefaction efficiency and higher oil yields than oo 0: °15 before.

:6.

According to the present invention, the powdery iron ore should have an average particle size not greater than 10 pm so that it has a sufficient specific surface area for efficient contact with coal. The average particle size ~should preferably be not greater than 5 pm, especially not greater than 1 pm.

Such powdery iron ore can be produced by pulverizing iron ore by wet process in a grinder (such as ball mill and tower mill) containing part of the recycled solvent for coal liquefaction.

By "recycled solvent for coal liquefaction" is meant a solvent used to \27M/96LPCOAL.SP,7 -8prepare a slurry mixture of coal, solvent, and catalyst. In the course of hydrogenation, this solvent is recovered from the hydrogenation product by distillation. Subsequently, the recovered solvent is mostly recycled to the step of slurry preparation and partly supplied to the other steps. That is, the recycled solvent is partly supplied to the grinder for use as a grinding medium of iron ore.

The solvent used for preparing a slurry mixture is a petroleum solvent selected from fractions having a boiling point of 180-450°C, depending on the reaction conditions employed for coal liquefaction. During recycling between the slurry preparation and the solvent recovery, it changes in its properties and, after operation for tens of hours, it becomes to exhibit almost invariable properties.

Since coal liquefaction needs a huge amount of recycled solvent S (which is 1-3 times as much as coal), it is common practice to use as the S13 recycled solvent part of oil (especially middle oil and/or heavy oil rather than liglht oil) separated after liquefaction.

9Unlike the conventional pulverized iron ore (which is liable to aggregation in the solvent), the powdery iron ore prepared by pulverizing in the 9oco recycled solvent according to the present invention hardly aggregates in the o *9 solvent. A probable reason for this is as follows: The strong tendency to 9 aggregation of the conventional pulverized iron ore is due to the fact that the Smechanically pulverized particles have extremely unstable rupture surfaces and also have a very small particle diameter. By contrast, the powdery iron ore in 2712196LPCOAL.SPE,8

II

-9the present invention carries on its rupture surface the recycled solvent for coal liquefaction although its particle size is as small as the conventional one. The recycled solvent contains polar substances, and the polar substances absorbed onto the rupture surface of mechanically pulverized particles prevent the aggregation of particles in the solvent.

As mentioned above, the powdery iron ore catalyst in the present invention has little tendency to aggregation in the solvent, good dispersibility, and high catalytic activity. In addition, it has a high affinity for coal, which leads to high catalyst efficiency and high catalytic activity. A probable reason for this is as follows: The recycled solvent for coal liquefaction becomes to have invariable properties after its repeated recycling, as mentioned above. The solvent with invariable properties has a composition similar to that of the solvent generated by coal liquefaction. Therefore, it has a high affinity for coal.

~Thus the powdery iron ore carrying the recycled solvent thereon has a high .*too: .9 15 affinity for coal.

~The process of coal liquefaction as defined in Claims 2 and 3 in the present invention is explained in the following.

:..";Claim 2 covers a process of coal liquefaction including the steps of 99** hydrogenating pulverized coal in the presence of solvent and catalyst, o separating the solvent from the hydrogenation product, introducing part of the *0 separated solvent into a pulverizer, and pulverizing iron ore in the solvent into S pulverized iron ore having an average particle diameter not greater than 10 pm, ,--wherein the pulverized iron ore is used as the catalyst.

27/2/96LPCOAL.SPE,9 The process of coal liquefaction as defined in Claim 2 is applicable in the case where the hydrogenation product is separated from the solvent. Part of the separated solvent is introduced into a pulverizer in which iron ore is mechanically pulverized into particles having an average particle diameter not greater than 10 pm, and the resulting powdery iron ore is used as the catalyst.

The solvent introduced into the pulverizer is the recycled solvent for coal liquefaction. u rts the process defined in Claim 2 produces the same effect as the process defined in Claim 1.

Claim 3 covers a process of coal liquefaction including the steps of preparing a slurry mixture composed of coal, solvent, and catalyst, heating the slurry mixture for coal hydrogenation, separating oil fractions from the hydrogenation product, recycling part of the solvent (as part of the separated oil fractions) to the step of preparirg a slurry mixture, introducing part of the solvent separated from the oil fractions into a pulverizer, pulverizing iron ore S15 having an average particle diameter not greater than 10 pm, wherein the .96 pulverized iron ore is used as the catalyst.

0o *.;.9The process of coal liquefaction as defined in Claim 3 is applicable in the case where the hydrogenation product is separated from the oil fractions (such as light oil, middle oil, and heavy oil) as the desired products. The oil fractions contain a solvent in the form of middle oil and/or heavy oil. Part of this solvent is recycled to the step of slurry preparation. And other part of this .9 9 S separated solvent is introduced into a pulverizer in which iron ore is mechanically pulverized into particles having an ave:age particle diameter not 2712/LPCOAL.SPE,1O S11greater thar 10 pm, and the resulting powdery iron ore is used as the catalyst.

The solvent introduced into the pulverizer is the recycled solvent for coal liquefaction. Thus the process defined in Claim 3 produces the same effect as the process defined in Claim 1.

The process of coal liquefaction as defined in Claims 1 to 3 should preferably employ the catalyst in an amount of 0.1-10 wt% of coal on dry ashfree basis as defined in Claim 4. With an amount less than 0.1 wt%, the catalyst does not afford the desired yield of oil. With an amount in excess of wt%, the catalyst causes erosion to the apparatus. An adequate amount is 0.5-8 wt% from the standpoint of economy (pulverizing cost and yields).

There are no restrictions on the iron ore to be pulverized into the catalyst so long as it has the catalytic function for coal liquefaction. It includes, for example, natural pyrite, limonite, hematite, and magnetite. Of these iron ores, pyrite is desirable because it is abundant and needs no cocatalyst (sulfur), *9*9*9 "1 as defined in Claim Thcr-e are no restrictions on the method of separating solvent or oil 9 from the hydrogenation product. Separation may be accomplished by distillation (under conditions adequate for desired products) or filtration.

The powdery iron ore catalyst in the present invention may be used 26 in conjunction with a cocatalyst which is sulfur (as simple substance) or a sulfur compound (such as hydrogen sulfide). This cocatalyst accelerates the reaction 9.

for coat liquefaction. The cocatalyst should be used in an amount (as sulfur) of 0.1-3 times the amount of iron in the powdery iron ore catalyst. This amount 27/2196LPCOAISPE,I1 t i C)r~ -12may be reduced in proportion to the content of sulfur co. ,pounds in coal.

The process of coal liquefaction as defined in the Claims of 1 to 5 in the present invention may be applied to brown coal (with a low degree of coalification), subbituminous coal, and bituminous coal. Usually coal is used in the form of particles, finer than about 60 mesh, pulverized after drying to a water content less than 15%. Pulverized coal is favorable to liquefaction.

Hydrogenation may be carried out under any conditions; usually at 350-500*C for 10-120 minutes, with the hydrogen partial pressure being 7-20 MPa. The hydrogenation product is separated from solids such as catalysts and recovered as such (in the form of oil) or fed to a distillation column for separation into desired fractions (such as heavy oil, middle oil, and light oil). Part of the heavy oil (as the recycled solvent) is recycled to the step of slurry preparation.

0:

EXAMPLES

so**: .1 5 The invention will be described in more detail with reference to the

S

following examples.

Example 1 Coal liquefaction was carried out according to the flowsheet in Fig. 1.

The process starts with the preparation of a slurry. The coal slurry preparing vessel is charged with dry pulverized coal, part of the recycled S* solvent recovered from the distillation column mecharically pulverized iron *e S ore catalyst, and sulfur (cocatalyst) recovered from the desulfurizer They are mixed into a slurry mixture. The pulverized iron ore catalyst is prepared by R 1 27I/296LPCOAL.SPE,12 -13mechanically pulverizing iron ore in a grinder containing part of the recycled solvent. Pulverizing is carried out to give particles having an average particle diameter not greater than 10p m.

The slurry mixture is transported to the preheater via the slurry pump. In the course of transportation, hydrogen is added. The slurry is introduced into the reactor of continuous stirred tank type, flow tubular type, or bubble column type. Liquefaction in the reactor is carried out at 380- 480'C for 10-60 minutes under a hydrogen pressure of 6-25 MPa. Up to this point, the feed coal undergoes dissolution and extraction with the recycled solvent and hydrogenation and decomposition by the catalyst, and becomes soft, turning into the desired product.

After the completion of liquefaction, the reaction mixture is introduced into the gas-liquid separator The liquid free gas is transferred to the desulfurizer in which sulfur is recovered. The recovered sulfur is S transferred to the coal slurry preparing vessel and other gas components are recovered as offgas.

ooo.i The solids and liquids remaining in the gas-liquid separator are transferred to the distillation column in which they are separated into light i: oil, middle oil, and heavy oil as products. Part of the middle oil and heavy oil (as the recycled solvent) is partly recycled to the coal slurry preparing vessel At the same time, part of the middle oil and heavy oil (as the recycled o.

solvent) is introduced into the pulverizer in which iron ore is mechanically pulverized. The resulting pulverized iron ore catalyst is supplied to the coal .27/2J96LPCOAL.SPE,13 -14slurry preparing vessel Simultaneously, dry pulverized coal is also supplied to the coal slurry preparing vessel After repetition of the above-mentioned procedure, it was found that the pulverized iron ore catalyst did not aggregate but remained completely dispersed in the solvent of the slurry mixture. In addition, the catalyst was active enough for the desired effect.

Example 2 Pulverized iron ore (pyrite) having an average particle diameter of pm was prepared as follows by using "Ultrafine Mill" (made by Mitsubishi Heavy Industries, Ltd.) as the pulverizer. The pulverizer was charged with kg of pyrite (from Tasmania) and 6 kg of recycled solvent having a boiling point of 180-420°C. (This recycled solvent is one which is used for liquefaction of brown coal). Pulverizing of pyrite in the recycled solvent was carried out for 6 hours.

Then, a slurry mixture was prepared from brown coal (from Australia), the above-mentioned pulverized iron ore catalyst, and the recycled solvent. The amount of the pulverized iron ore catalyst was 7.0 wt% (as pyrite) of brown coal on dry ash-free basis.

The slurry mixture was introduced into a 5-liter autoclave.

Hydrogenation (liquefaction) was carried out at 450°C for 60 minutes under an initial hydrogen pressure of 9.0 MPa. The hydrogenation product was separated and distilled for separation into oil fractions according to their boiling points. It was found that the yield of oil to fractions having a boiling point I7 '27/2/96LPCOAL,SPE.14 lower than 420°C) was 44 wt% of coal on dry ash-free basis.

For comparison, pulverized iron ore having an average particle diameter of 0.5 pm was prepared by pulverizing (by dry process) 10 kg of pyrite ore in "Ultrafine Mill" for about 3 hours in a nitrogen stream. Using the pulverized iron ore as the catalyst, coal liquefaction and distillation were carried out in the same manner as and under the same conditions as mentioned above.

The yield of oil to fractions having a boiling point lower than 420°C) was 39 wt% of coal on dry ash-free basis.

Comparative Example 1 Natural pyrite was pulverized to give pulverized pyrite catalyst having an average particle diameter of 2.6 pm. The same procedure as in Example 3 was repeated except that the sulfided catalyst of pulverized wolframite was replaced by the pulverized pyrite catalyst and sulfur was not added. The yield of oil to fractions having a boiling point lower than 420°C) was 24.8 wt% of coal on dry ash-free basis.

Incidentally, the amount of the catalyst added (or the content of the pulverized pyrite catalyst in the slurry mixture) was 3.0 wt% (as pyrite) of coal on dry ash-free basis. This catalyst amount is substantially equivalent to the catalyst amount in Example 1.

Comparative Example 2 S(a) a-iron oxyhydroxide catalyst in the form of powder having an average particle diameter of 18 pm was prepared in the same manner as in Example 2 of copending application NoAS. o% b, except that the amount of 2712/96LPCOAL.SPE,15 -a4 6- OCC -16- 3.4 wt% aqueous solution of ammonia was changed to 563 g and the aqueous solution of diammonium hydrogen phosphate was not added. This powder was identified as a-iron oxyhydroxide and was found to have a specific surface area of 80 m 2 This powder is referred to as "Catalyst B" hereinafter.

Catalyst B was mechanically pulverized in the recycled solvent for brown coal liquefaction using a planetary mill containing balls with a diameter of 2.4 mm. Thus there was obtained a slurry of a-iron oxyhydroxide catalyst. This catalyst was found to have an average particle diameter of 0.8 'pm.

A slurry mixture was prepared in the same manner as in Example 2 of co-pending application No.48' 3S96 except that they y-iron oxyhydroxide catalyst slurry was replaced by the a-iron oxyhydroxide catalyst slurry.

Hydrogenation and fractionation were carried out in the same manner as in that Example. The yield of oil (C 5 to fractions having a boiling point lower than 1 420°C) was 44 wt% of coal on dry ash-free basis, as shown in Fig. 4 (the left square).

Comparative Example 3 Catalyst B (obtained in Comparative Example 2) was pulverized in the recycled solvent for brown coal liquefaction using a planetary mill containing balls with a diameter of 10 mm. Thus there was obtained an a-iron oxyhydroxide catalyst slurry. This catalyst has an average particle diameter of 1.8 pm. A slurry mixture was prepared in the same manner as in Example No.

2 of co-pending application No.i~ Mkexcept that the y-iron oxyhydroxide 27/2/96LPCOAL.SPE,16 -17catalyst slurry was replaced by the above-mentioned a-iron oxyhydroxide catalyst slurry. Using this slurry mixture, hydrogenation and fractionation were carried out in the same manner as in that Example. The yield of oil to fractions having a boiling point lower than 420°C) was 38 wt% of coal on dry ash-free basis, as shown in Fig. 4 (the right square).

Comparative Example 4 Natural pyrite (iron ore) was pulverized using a pneumatic pulverizer (made by Nisshin Engineering Co., Ltd.). Thus there was obtained a pulverized pyrite catalyst having an average particle diameter of 2.6 pm. This catalyst is referred to as "Catalyst C" hereinafter. A slurry mixture was prepared from brown coal (from Australia), Catalyst C, and solvent for coal liquefaction. The amount of Catalyst C was 7.0 wt% (as pyrite) of coal on dry ash-free basis.

Hydrogenation and fractionation were carried out in the same manner as in Example No. 2 of co-pending application No.'S2oS-31, except that the y-iron 1 oxyhydroxide catalyst slurry was replaced by the above mentioned slurry mixture. The yield of oil (C5 to fractions having a boiling point lower than

*I

420°C) was 33 wt% of coal on dry ash-free basis, as shown in Fig. 4 (the right triangle).

Comparative Example S°2© Catalyst C (obtained in Comparative Example 4) was pulverized using a pneumatic pulverizer to give a pulverized pyrite catalyst having an average particle diameter of 0.5 pm. A slurry mixture was prepared in the same manner as in Comparative Example 4, except that the pulverized pyrite catalyst (having T 27I/2/LPCOAL.SPE,17 18an average particle diameter of 2.6 pm) was replaced by the pulverized pyrite catalyst (having an average particle diameter of 0.5 Using this slurry mixture, hydrogenation and fractionation were carried out in the same manner as in Comparative Example 4 (or Example The yield of oil to fractions having a boiling point lower than 420°C) was 39 wt% of coal on dry ash-free basis, as shown in Fig. 4 (the left triangle).

It was demonstrated that the process of coal liquefaction in the present invention permits higher oil yields owing to the high catalytic activity than the conventional process that employs pulverized iron ore catalyst.

S

e* S 5* 27/2/96LPCOAL.SPE,18

Claims (1)

19- The claims defining the invention are as follows: 1. A process of coal liquefaction by hydrogenation of pulverized coal in the presence of solvent and catalyst, wherein the catalyst is powdery iron ore having an average particle diameter not greater than 10 pm which has been mechanically pulverized in the recycled solvent for coal liquefaction. 2. A process of coal liquefaction including the steps of hydrogenating pulverized coal in the presence of solvent and catalyst, separating the solvent from the hydrogenation product, introducing part of the separated solvent into a pulverizer, and pulverizing iron ore in the solvent into pulverized iron ore having an average particle diameter not greater than 10 pUm, wherein the pulverized iron ore is used as the catalyst. 3. A process of coal liquefaction including the steps of preparing a slurry mixture composed of coal, solvent, and catalyst, heating the slurry mixture for coal hydrogenation, separating oil fractions from the hydrogenation product, recycling part of the solvent (as part of the separated oil fractions) to the step of preparing a slurry mixture, introducing part of the solvent separated from the oil fractions into a pulverizer, pulverizing iron ore in the solvent into pulverized iron ore having an average particle diameter not greater than 10 pm, oQ S wherein the pulverized iron ore is used as the catalyst. '2 4. A process of coal liquefaction as defined inany of Claims 1 to 3, wherein the amount of the catalyst is 0.1-10 wt% of the amount of coal on dry ash-free basis. A process of coal liquefaction as defined in any of Claims 1 to S *a S 2MI/96LPCOALSPE,19 4, wherein the raw material of the pulverized iron ore is natural pyrite. 6. A procesa of coal liquefaction including thc otop of hydrogenating coal in the presence of solvent and catalyst, w ibee the catalyst is wolframite. 7. A process o a liquefaction as defined in Claim 3 wherein coal, solventa catalyst coexist with sulfur (as a simple substance) or a sulfur rmpound----. D A T E D this 27th day of February, 1996. NIPPON BROWN COAL LIQUEFACTION CO., LTD By their Patent Attorneys: CALLINAN LAWRIE t** *0a* a. a 27/2/96LPCOAL.SPE,20 ABSTRACT OF THE DISCLOSURE A process of coal liquefaction by hydrogenation of pulverized coal in the presence of solvent and catalyst, wherein the catalyst is powdery iron ore having an average particle diameter not greater than 10 J.m which has been mechanically pulverized in the recycled solvent for coal liquefaction. S e 37