JPH06287567A - Coal liquefaction - Google Patents

Abstract

PURPOSE:To liquefy coal at high conversion in high yields by irradiating a coal slurry prepared by mixing feed coal with a solvent and a catalyst with a radiation and subjecting the irradiated slurry to a coal liquefaction reaction in a reducing gas atmosphere. CONSTITUTION:A coal slurry is obtained by feeding a coal slurry obtained by mixing dried feed coal with a solvent in a solvent/coal weight ratio of 1.0-4.0 and 0.5-5wt.%, based on dry coal, fine catalyst particles having a content of 16mum or smaller particles of 90% or above to a preparation tank 9, and mixing the mixture at 40-100 deg.C under a pressure of 1-10 atm in an inert gas atmosphere. The obtained slurry is sent to an irradiator 42 through a circulation pump 41 and a pipe 11 and is irradiated at a dose of 10<2>-10<10> R at 40-100 deg.C under a pressure of 1-10 atm. This slurry is pressurized with a high-pressure pump 12 to 100-200 atm, heated with a heater 16 to 350-450 deg.C, fed to a coal liquefaction tower 10 and subjected to a coal liquefaction reaction at 400-500 deg.C for 40-80min in a reducing gas atmosphere.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel coal liquefaction method using radiation. More specifically, after irradiating a certain amount of radiation as a pretreatment to a coal slurry prepared by mixing coal, a solvent and a catalyst,
The present invention relates to a coal liquefaction method in which a coal liquefaction reaction is performed under a reducing gas atmosphere under high temperature and high pressure conditions.

[0002]

2. Description of the Related Art In recent years, the need for alternative energy has come to be recognized with the exhaustion of petroleum resources and the rise in oil prices, and many studies have been conducted on the liquefaction reaction of coal as one of the alternative energy. ing.

Regarding such a coal liquefaction method, to date, a slurry prepared by mixing coal, a solvent and a catalyst is subjected to a liquefaction reaction by hydrogenation in the presence of a catalyst at a high temperature and a high pressure, and a liquefied oil obtained is lightened. Oil, medium oil, and heavy oil (including residue) are separated and refined. Of the obtained liquefied oil, heavy oil (including residue) is distilled under reduced pressure to remove heavy oil and residual components. After separation of and, the obtained heavy oil is subjected to a hydrogenation reaction in a hydrogenation reaction tower, the solvent obtained is returned, and a coal liquefaction method in which it is circulated again as a coal liquefaction solvent is well known. There is. In the liquefaction of such coal, an oil obtained by hydrogenating a coal liquefaction-produced heavy oil is used as a solvent for coal liquefaction, a raw coal, a catalyst, and the like are mixed to prepare a slurry, and then subjected to a liquefaction reaction, It is intended to facilitate the transfer of hydrogen during the liquefaction reaction by increasing the hydrogen donating ability of the coal liquefaction solvent, thereby promoting the liquefaction reaction.

FIG. 2 is a schematic view showing an embodiment of a coal liquefaction apparatus in a coal liquefaction method known as the prior art.

From FIG. 2, the coal liquefaction apparatus 5 in the conventional method is shown.
As the structure of 1, a coal storage tank 2, a solvent storage tank 3 and a catalyst storage tank 4 are provided, and these are all provided on the upper head of a coal slurry preparation tank 9 equipped with an agitator 8 through pipes 5, 6 and 7. Each is connected. Further, the bottom tank portion of the coal slurry preparation tank 9 is connected to the bottom tower portion of the coal liquefaction reaction tower 10 by a pipe 11, and a high pressure pump 12 is provided on the path of the pipe 11. Further, a pipe 14 is connected to the hydrogen storage tank 13, and the other end of the pipe 14 is connected to the path of the pipe 11 on the reaction tower 10 side from the high pressure pump 12 so that high pressure hydrogen gas can be supplied.
Further, a heater 16 is provided on the outer peripheral portion of the pipe 11 on the reaction tower 10 side. Next, the head tower part of the coal liquefaction reaction tower 10 is connected to the upper part of the separator 17 by a pipe 18. Further, the upper part of the separator 17 is connected to the atmospheric distillation column 19 via the pressure reducing valve, and the lower part of the separator 17 is connected to the vacuum distillation column 20 via the pressure reducing valve by pipes 21 and 22, respectively. The head tower section and the bottom tower section are the product gas collector 2
3, light and medium oil collector 24 and water collector 25 are connected by pipes 26, 27 and 28, respectively. On the other hand, the bottom column of the vacuum distillation column 20 is connected to the residue collector 29,
After the head part of the vacuum distillation column 20 is once returned to normal pressure, it is connected to the head part of the hydrogenation reaction column 30 via a normal pressure pump by pipes 31 and 32, respectively, and the bottom of the hydrogenation reaction column 30 is connected. The tower portion is connected to the solvent storage tank 3 by a pipe 33.

A method for liquefying coal by using the coal liquefying apparatus 51 having the above structure will be described in detail.

First, the raw coal from the coal storage tank 2 and the circulating solvent for coal liquefaction from the solvent storage tank 3 are pipes 5 and 6, respectively.
To the coal slurry preparation tank 9 through which the catalyst is simultaneously heated from the catalyst storage tank 4 through the pipe 7 at about 60 ° C. under normal pressure at the same time to increase the liquefied oil yield. 9 and mixed using a stirrer 8 to prepare a coal slurry.

Here, as the raw material coal stored in the coal storage tank 2, in order to carry out the hydrocracking reaction in the coal liquefaction reaction, the water content of 5 to 30% by weight contained in the coal is usually 1-2. It is coal that has been dried to a weight percentage and then pulverized so that the yield of coal particles with a particle size of 150 μm or less is 80% or more. For crushing the coal, any crusher such as a rod mill, a ball mill, a vibration mill or a disc mill can be used.

The concentration of the coal slurry is usually in the range of about 1.0 to 3.0 in terms of the weight ratio of the solvent to the dry weight of the raw material coal (solvent / raw material coal), and the amount of catalyst added is Usually 1 for dry, ashless base coal
It is prepared so as to be in the range of about 5%.

Further, as the catalyst, an iron-based catalyst which is relatively inexpensive and easily available is mainly used, and specifically, a synthetic iron sulfide catalyst or a natural iron ore catalyst is used.

The coal slurry thus obtained is pressurized by the high-pressure pump 12 to a pressure of 150 to 190 kg / cm ² and charged into the system. At that time, the hydrogen in the hydrogen storage tank 13 is pressurized to the same pressure by a compressor or the like, and the obtained high-pressure hydrogen gas is supplied into the system to form a hydrogen atmosphere. Thereafter, the coal slurry is further heated by the heater 16 to 380 to 380.
After being heated to 450 ° C., the coal liquefaction reaction tower 10 reacts with the hydrogen gas to hydrocrack.

In the hydrogenolysis at this time, the reaction temperature is usually 430 to 470 ° C. and the pressure is 150 to 190 kg / cm ^2.
The liquefaction reaction of the raw material coal proceeds by the decomposition reaction.

The product after the coal liquefaction reaction is sent to the separator 17 through a pipe 18, and the separator 17 produces product gas, water and light and medium oil (usually a boiling point fraction of C _{5 to} less than 260 ° C.). 2) and a heavy oil (usually a boiling point fraction of 260 ° C. or higher) and a residue. Of these, the components consisting of the produced gas, water, and light-medium oil are sent to the atmospheric distillation column 19 through the pipe 21, through the pressure reducing valve,
The produced gas, water, and light / medium oil components are separated and separated and collected in the produced gas collector 23, the light / medium oil collector 24, and the water collector 25.

Further, the light / medium component can be separated into a light oil and a medium oil by a distillation operation, if necessary, and can be recovered as predetermined product oils.

On the other hand, the component consisting of heavy oil and residue is
It is sent to the vacuum distillation column 20 through a pipe 22 through a pressure reducing valve, and in the vacuum distillation column 20, vacuum distillation (10 to 50 torr) is performed.
Those having a boiling point of 538 ° C. or higher are discharged to a residue collector 29 through a pipe 31 and removed as a liquefaction residue.

On the other hand, heavy oil having a boiling point of less than 260 to 538 ° C. is once returned to normal pressure, and then a high pressure pump (not shown) and a heater (not shown) provided on the pipe 32 path. ) Is sent under high temperature and high pressure to a fixed bed hydrogenation reaction column 30 filled with a catalyst such as Ni-Mo, and the hydrogenation reaction is usually performed in a hydrogen atmosphere at 300 to 380 ° C and 80 to 120 atm. In the column 30, LHSV is usually reacted with hydrogen gas for 1 to 2 hours to carry out a hydrogenation reaction to enhance the hydrogen donating property, and a solvent composed of a component such as tetralin can be produced. The obtained solvent is circulated and used as a coal liquefaction solvent by returning it to the solvent storage tank 3 through the pipe 33.

However, in the conventional coal liquefaction technology in which the liquefaction reaction is further improved by facilitating the transfer of hydrogen by the coal liquefaction solvent having such a hydrogen donating ability, in view of economy, it is still a substitute for petroleum. It is the current situation that the development of a coal liquefaction method capable of obtaining a better conversion rate and liquefied oil yield is not reached to a level where it can be put to practical use as energy.

Fine coal, such as the liquefaction reaction of coal, which has been studied as one of the above-mentioned alternative energy sources for petroleum,
As a completely different process from the method of producing fuel oil (light oil, medium oil) through liquefaction of coal under high temperature and high pressure conditions, especially hydrocracking, in a reducing atmosphere, a slurry in which a coal-based solvent and a catalyst are mixed, Solvent extraction to produce colloidal fuel or heavy oil fuel in a broad sense by decomposing and liquefying coal at high temperature using solvent such as anthracene oil or petroleum heavy oil without hydrogen or catalyst A coal liquefaction method is known.

In the method for liquefying coal by the above solvent extraction,
As a method for improving the point that a considerably high temperature is required for solvent extraction, there is a method of accelerating the solvent extraction of coal by irradiating the coal in the presence of solvent with radiation.
No. 5 is described.

According to the above-mentioned liquefaction method using radiation for solvent extraction of coal, it is noted that the high molecular weight substance is decomposed by ionizing radiation even at around room temperature, and based on this finding, the high molecular weight coal is By generating a low molecular weight substance by irradiating with radiation instead of thermal decomposition,
It is possible to increase the solubility in a coexisting solvent without bringing it to a high temperature state, and to increase the yield of a desired heavy oil fuel when radiation irradiation is also used at a high temperature condition. Is.

However, the above-mentioned method for liquefying coal by solvent extraction is intended to produce a colloidal fuel or a heavy oil fuel from coal, and therefore, even when molecules decomposed by irradiation with radiation are polymerized depending on conditions. Although it is not a problem, in order to apply this liquefaction method using radiation for solvent extraction of coal to the method of producing fuel oil (light oil, medium oil) from coal, the temperature and pressure conditions during irradiation are extremely wide. ,
Also, proper irradiation conditions are not specified, and the yield of fuel oil decreases conversely under conditions that cause polymerization, such as liquefaction of coal that can obtain better conversion and liquefied oil yield. It couldn't be a method.

Further, in the liquefaction method using the above-mentioned radiation, the yield of the solvent-soluble component of the desired heavy oil fuel is about 2 to 13% by weight under normal temperature and pressure. The amount of increase in solvent-soluble content is as low as 0.5 to 5% by weight as compared with the case where it is not used, coal cannot be fully utilized as a heavy fuel oil, and the above-mentioned radiation-based liquefaction method is used. In order to obtain a higher yield, in order to obtain a higher yield, the liquefaction reaction condition by solvent extraction of coal can be obtained by subjecting it to high temperature and high pressure and irradiating it (long irradiation if necessary). The coal liquefaction reactor for solvent extraction of coal must be combined with high temperature and high pressure equipment and radiation equipment, but these processes are likely to be extremely complicated, and many new problems to be solved will also arise. For such a process it has not been what, etc. described.

Therefore, when applying the method for producing fuel oil (light oil, medium oil) through liquefaction of coal, particularly hydrocracking, appropriate irradiation conditions are set so that polymerization does not occur, and further, at normal temperature and normal pressure. It is necessary to solve the same problems as the above method such as improvement of the liquefied oil yield or construction of a simple process under high temperature and high pressure, and today, based on the above liquefaction method using radiation, a better conversion rate and At present, it is still difficult to easily invent a method for producing a fuel oil (light oil, medium oil) that can achieve a high liquefied oil yield.

[0024]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is, as one of petroleum alternative energy, a slurry obtained by mixing pulverized coal, a coal-based solvent and a catalyst in a reducing gas atmosphere at high temperature and high pressure. Liquefaction method of producing fuel oil (light oil, medium oil) through coal liquefaction under conditions, especially hydrocracking, to obtain better conversion and liquefied oil yield by using relatively simple process It is intended to provide a coal liquefaction method that can be performed.

[0025]

In order to achieve the above object, the inventors of the present invention liquefy coal in a reducing gas atmosphere under high temperature and high pressure conditions using a coal slurry in which pulverized coal, a coal-based solvent and a catalyst are mixed. In particular, we have intensively researched a new coal liquefaction method for producing fuel oil (light oil, medium oil) through hydrocracking. Especially, focusing on the fact that a chemical reaction occurs by irradiation with radiation at the stage of coal slurry and the properties of coal change, various studies were conducted to apply irradiation to the pretreatment technology of the liquefaction reaction of coal. As a result, by irradiating the coal slurry with radiation, the unit skeleton structure has a polycyclic structure rich in aromaticity, and the solvent penetrates into coal forming a polymer by connecting them with a bridge. However, it has been found that the solvent can form a swollen state in coal by preliminarily relaxing the coal structure by breaking the bond of molecules in the coal to generate ions and free radicals. This facilitates liquefaction of coal, particularly hydrocracking under high-temperature and high-pressure conditions of the coal slurry under a reducing gas atmosphere, so that the liquefied oil yield can be improved and the reaction conditions can be mild, and this pretreatment Part (low temperature and low pressure)
Since it is only necessary to add the process of, it can be a very simple process. The present invention has been completed based on these findings.

That is, the object of the present invention is to (1) irradiate a coal slurry in which a raw material coal, a solvent and a catalyst are mixed, with radiation, and then carry out a coal liquefaction reaction under high temperature and high pressure conditions in a reducing gas atmosphere. It is achieved by the coal liquefaction method.

In the present invention, (2) the radiation dose by irradiation with radiation is in the range of 10 ² to 10 ¹⁰ roentgens, and (3) the temperature at the time of irradiation with radiation is 40 to 100.
It is preferable that the temperature and the pressure are 1 to 10 atmospheres.

The object of the present invention is (4) the irradiation of radiation while circulating the coal slurry (1) to (3).
It is also achieved by the coal liquefaction method shown in any one of.

In the present invention, (5) the concentration of the coal slurry is 1.0 to 4.0 in the weight ratio of the solvent to the dry weight of the raw coal (solvent / coal of the raw material), and (6)
It is preferable that the catalyst be fine particles having a yield of 90% or more and 16 μm or less.

Further, in the present invention, (7) the blending amount of the catalyst with respect to the coal slurry is 0.5 to 5% by weight based on the dry weight of the raw coal, and (8) the high temperature and high pressure during the coal liquefaction reaction. The conditions are a temperature of 400 to 500 ° C. and a pressure of 10
The pressure is preferably 0 to 200 atm.

[0031]

According to the present invention, a coal slurry in which pulverized coal, a coal-based solvent, and a catalyst are mixed is liquefied under high-temperature and high-pressure conditions under a reducing gas atmosphere, and particularly fuel oil (light oil, medium oil) is obtained through hydrocracking. In the coal liquefaction method for producing, by irradiating the stage of the coal slurry, the coal structure is relaxed in advance, the solvent is swollen to form a state of coal, thereby the coal slurry under a reducing gas atmosphere,
By improving the efficiency of hydrocracking of coal under high temperature and high pressure conditions, the yield of liquefied oil can be improved, the reaction conditions can be made mild, and the process of the pretreatment part (low temperature and low pressure) can be added. It is a coal liquefaction method consisting of a process.

Hereinafter, the present invention will be described in more detail based on the embodiments.

FIG. 1 is a state of use diagrammatically showing the construction of an embodiment of a coal liquefaction apparatus used in a coal liquefaction method according to the present invention.

As shown in FIG. 1, as a coal liquefaction apparatus 1 according to the present invention, a circulation pump 41, a radiation irradiation device 42 and an automatic valve 43 are provided on a pipe 11 route from a coal slurry preparation tank 9 to a high pressure pump 12. The configuration other than the radiation irradiation device 42 installed on the pipe 11 between the valve 43 and the coal slurry preparation tank 9 has the same configuration as the above-described conventional coal liquefaction device 51 shown in FIG. In FIG. 1, the same components as those in the coal liquefaction device 51 shown in FIG. 2 are designated by the same reference numerals.

In order to obtain liquefied oil and the like by liquefying coal according to the method of the present invention using the coal liquefaction apparatus 1 having the above-mentioned structure, coal particles crushed to a certain particle size or less are used in the coal storage tank. 2 through the pipe 5, the solvent from the solvent storage tank 3 through the pipe 6 for facilitating the transfer of hydrogen, and the catalyst through the catalyst storage tank 4 and the pipe 7 for increasing the liquefied oil yield. 9, the mixture is mixed by the stirrer 8 while maintaining a constant tank atmosphere, pressure and temperature conditions to produce a coal slurry having a constant concentration.

Here, the raw material coal stored in the coal storage tank 2 and used in the coal liquefaction method of the present invention is not particularly limited, and can be used for all bituminous coals, subbituminous coals, brown coals and the like. Preference is given to bituminous coal, subbituminous coal and the like having a low oxygen content.

As the raw material coal, in order to carry out the hydrocracking reaction in the liquefaction reaction, usually 5 to 30% by weight of water contained in the coal is dried to 1 to 2% by weight, and then usually 1
The yield of coal particles having a particle size of 50 μm or less is 80% or more, and preferably the yield of coal particles having a particle size of 150 μm or less is 90.
%, More preferably coal pulverized so that the yield of coal particles having a particle size of 150 μm or less is 100%. If the yield of the raw material coal is less than 80% of the coal particles having a particle size of 150 μm or less, operational troubles are likely to occur and the liquefaction reaction is not sufficient, which is not preferable. For pulverizing the coal, a rod mill, a ball mill, a vibration mill,
Any crusher such as a disc mill can be used.

Further, as the solvent used in the present invention,
It is desirable to use an oil having a hydrogen donating ability, for example, an oil having a high content of aromatic components such as tetralin and tetrahydroanthracene. For example, a coal-based oil obtained by hydrogenating the heavy oil obtained by the method of the present invention. A solvent (including tetralin and the like) can be used. By circulating and using the coal-based solvent, it is possible to reduce the cost without the need to separately prepare the solvent.

The catalyst is not particularly limited, but examples of the metal species having catalytic ability include, for example,
Iron, nickel, molybdenum, titanium, vanadium and lanthanum, and the like, preferably, relatively inexpensive and easily available, iron with a large catalytic action in the coal liquefaction reaction, nickel, etc., usually an iron-based catalyst, A nickel-based catalyst, a cobalt-based catalyst, a titanium-based catalyst, a zeolite-based catalyst, a molybdenum catalyst, a vanadium catalyst, a cobalt-molybdenum-based catalyst, a lanthanum catalyst, or the like can be used, but is preferably relatively inexpensive and easily available. Iron-based catalysts are desirable, and specific examples thereof include synthetic iron sulfide catalysts, iron hydroxide or natural iron ore catalysts.

Next, the concentration of the coal slurry in the coal slurry preparation tank 9 is usually 1.0 to 4.0, preferably 1. 0 in the weight ratio of the solvent to the dry weight of the raw coal (solvent / coal of raw material). The range is 0 to 2.0, and more preferably 1.0 to 1.5. If the concentration ratio of the solvent to the dry weight of the raw coal exceeds 4.0 (solvent / coal of the raw material), the economical efficiency becomes too poor, the reaction efficiency is lowered, and the solvent to the dry weight of the raw coal is reduced. If the weight ratio (solvent / coal of raw material) is less than 1.0, the viscosity of the slurry becomes large, and mixing due to stirring is difficult to be uniform, and it takes a long time. It is not preferable such as clogging.

The amount of catalyst added to the coal slurry in the coal slurry preparation tank 9 is usually 0.5 to 5% by weight, preferably 1 to 4% by weight, based on the dry weight of the coal particles.
It is more preferably in the range of 2 to 3% by weight. When the addition amount is less than 0.5% by weight, sufficient effect due to the addition cannot be obtained, and when it exceeds 5% by weight, the effect corresponding to the addition amount cannot be increased. In addition, the economic efficiency will be poor.

On the other hand, the size of the catalyst varies depending on the kind to be used, but usually the yield of 16 μm or less is 90% or more,
The yield of 10 μm or less is preferably 90% or more, more preferably the yield of 1 μm or less is 90% or more. If the size of the catalyst is less than 16 μm and the yield is less than 90%, the catalytic activity is deteriorated, which is not preferable.

The atmosphere, pressure and temperature conditions of the coal slurry preparation tank 9 are usually an inert gas atmosphere, preferably a reducing gas atmosphere, and more preferably a hydrogen gas-containing atmosphere. , Temperature is usually 4
The temperature is 0 to 100 ° C., preferably 50 to 80 ° C., more preferably 50 to 70 ° C., and the pressure is usually 1 to 10 atm, preferably 1 to 5 atm, more preferably 1 to 2 atm.

When the temperature is lower than 40 ° C., the coal slurry concentration sufficient for stirring cannot be obtained, and when it exceeds 100 ° C., the volume fraction of coal particles increases due to the swelling phenomenon of coal, It is not preferable that the apparent slurry concentration is increased, the viscosity of the slurry is increased, and that the solvent is vaporized and the charging ports of the coal and the catalyst are wet and clogged at the time of charging.

Further, if the pressure is less than 1 atm, it is not preferable because the pressure may be changed to a negative pressure to mix air and oxidize coal, and if it exceeds 10 atm, it is suitable. It is not preferable from the standpoint of safety, because the above effect cannot be obtained.

Next, the coal slurry obtained in the coal slurry preparation tank 9 is supplied from the coal slurry preparation tank 9 to the circulation pump 4
1 is sent to the radiation irradiator 42 while being transported in the pipe 11 at a constant speed and irradiated with a constant radiation dose, and then the valve 43 is opened to allow the coal slurry to flow to the high pressure pump 12, and the high pressure pump 12 Until the coal slurry is sent to the liquefaction reaction system through the pipe or is irradiated with a constant radiation dose, the valve 43 is closed so as to be conveyed to the pipe 44, and is returned to the coal slurry preparation tank 9 through the pipe 44 for circulation. To be done. By repeating the circulation, all the coal slurry obtained in the coal slurry preparation tank 9 is irradiated with a constant radiation dose, and then the valve 43 is opened to allow the coal slurry to flow to the high pressure pump 12, and the high pressure pump 12 is used. The coal slurry may be sent to the liquefaction reaction system.

In the radiation irradiator 42, the radiation dose applied to the coal slurry flowing through the pipe 11 varies depending on the type of coal used, but is usually 10 ² -10.
^{The range is 10} roentgens, preferably 10 ⁴ to 10 ⁸ , and more preferably 10 ⁵ to 10 ⁷ . The radiation dose is 10 ²
If it is less than roentgen, it is not possible to sufficiently change the coal properties, even if the liquefaction reaction using the coal slurry, it is not possible to increase the target liquid oil yield, and When the radiation dose exceeds 10 ¹⁰ roentgen, there is no particular problem in changing the coal properties, but the cost of the device or the irradiation process is high, such as the size of the radiation device being large or the irradiation of radiation requiring a long time. It is not preferable in terms of safety.

The temperature at the time of irradiation of radiation in the radiation irradiation device 42 is preferably the same temperature condition as that of the coal slurry preparation tank 9 described above. This is not preferable because a radiation source is prevented from being melted by a high temperature, and when the temperature condition is changed, an extra device is required for irradiation of the radiation. Similarly, the pressure at the time of irradiation of radiation is slightly higher than the pressure of the coal slurry preparation tank 9 by the pressure increased by the circulation pump.
It is preferable to set the same pressure conditions as those of the coal slurry preparation tank 9 described above. This is not preferable from the viewpoint of preventing the danger that the high-pressure slurry will damage the radiation source when the pipe 11 is ruptured, and changing the conditions requires an extra device when irradiating the radiation.

Further, as the above-mentioned radiation, cobalt 6
Γ rays, β rays, electron beams or X rays obtained by using 0 etc. as a radiation source
It is possible to use relatively high energy radiation such as rays. Further, radioactive waste generated by the operation of a nuclear reactor, reprocessing of nuclear fuel, etc. can be effectively used as the radiation source.

The radiation irradiator 42 used in the present invention is not particularly limited, and an existing radiation irradiator can be used. For example, the radiation irradiator 42 is concentrically shielded with lead around the pipe 11 and externally exposed. Is equipped with a cylindrical fixing device that does not leak radiation, and a window through which only specific radiation such as β rays is transmitted is provided only on the inner peripheral part of the cylindrical fixing device, and the fixing device is loaded with a source of cobalt 60 or the like. However, by passing the coal slurry that is the irradiation target through the pipe 11, it is possible to irradiate the coal slurry with a certain amount of radiation, and only when the predetermined amount of radiation cannot be irradiated with one irradiation. It circulates a coal slurry. In the case of the device having the above structure, it is desirable that the material of the portion of the pipe 11 to which the radiation is applied is cooled so as not to be heated by being irradiated with the radiation for a long time. Further, preferably, the whole fixing device is placed in a water tank. This is because the radiation source is placed in the water, and the water can be used as a cooling agent, a moderator, and the like, which is preferable. Needless to say, the radiation irradiating device 42 used in the present invention is not limited to the device having the above-mentioned configuration, and an existing radiation device using any radiation source can be used.

Next, the coal slurry irradiated with the above-mentioned irradiation rays is pressurized to a constant pressure by the high-pressure pump 12 and charged into the system. At that time, the hydrogen in the hydrogen storage tank 13 is pressurized by a compressor or the like, and a high pressure reducing gas having the same pressure is supplied into the system to form a reducing gas atmosphere. Further heater 1
After being heated to a constant temperature by 6, the coal liquefaction reaction tower 1
It is charged at 0 at a constant slurry charging rate, and is reacted with the hydrogen gas in a reducing gas atmosphere to hydrocrack.

The pressure increase by the high-pressure pump 12 is usually 100 to 200 atm, preferably 130 to 190 atm, more preferably 160 to 180 atm. As the high-pressure pump 12, for example, a plunger type slurry pump can be used, and the slurry is sucked and compressed by the plunger to be supplied as a piston flow to the coal liquefaction reaction tower 10.

The high-pressure reducing gas supplied to the coal slurry is adjusted so as to have the same gas pressure as the pressure of the coal slurry. As the reducing gas, hydrogen gas and a mixture of hydrogen gas and recycled hydrogen gas recovered after the liquefaction reaction of the present invention (in this case, hydrogen gas purity of 80% or more is acceptable) can be used.

Further, the heater 16 is not particularly limited, and an induction type helical coil or the like can be used. The heater 16 heats the coal slurry to 350 to 450 ° C, preferably 380 to 430 ° C, and more preferably 390 to 410 ° C. If the heating temperature is lower than 350 ° C., it is not preferable because it takes time to reach a temperature suitable for hydrocracking after charging the coal liquefaction reaction tower 10, and if it exceeds 450 ° C. This is not preferable because it may cause hydrocracking and damage the pipe 11.

The reaction temperature in the coal liquefaction reaction tower 10 is usually 400 to 500 ° C., preferably 400 to 460.
C., more preferably 440 to 460 ° C., the pressure is the same as the pressure obtained by pressurization by the high-pressure pump 12 described above, and the reaction time (reaction tower residence time) is usually 40 to 80 minutes, preferably Is 50 to 70 minutes, more preferably 50 to 60 minutes (or the slurry charging rate is 100 to 70 minutes).
130 kg / hr, preferably 100-120 kg / h
r, more preferably 100 to 110 kg / hr). Under the decomposition reaction conditions, the liquefaction reaction of the raw coal proceeds. If the reaction temperature is lower than 400 ° C., the coal liquefaction reaction becomes insufficient and the amount of unreacted coal slurry increases to lower the yield of liquefied oil. If it exceeds 500 ° C., the liquefied oil produced by the hydrogenation reaction Is further decomposed, and the yield of liquefied oil is reduced, mainly due to the progress of gasification, which is not preferable. The gas pressure is 100
If the pressure is less than atmospheric pressure, the hydrogen liquefaction will be insufficient and the liquefaction reaction of coal will be insufficient and the yield of liquefied oil will be reduced.
When the pressure exceeds the atmospheric pressure, the liquefied oil is more likely to be decomposed and the equipment cost is increased, which is not economically preferable. Further, when the reaction time (reaction tower residence time) is less than 40 minutes, the coal liquefaction reaction becomes insufficient and the yield of liquefied oil decreases, and when it exceeds 80 minutes, the produced liquefied oil is further decomposed. It is not preferable because the yield of liquefied oil is lowered by receiving and gasifying it, or unnecessary equipment costs are required.

Further, in the present invention, the catalyst is added to the coal slurry in which the raw coal and the solvent are mixed as shown in FIG. 1, and the mixed coal slurry is supplied to the coal liquefaction reaction tower 10 to carry out the coal liquefaction reaction. Instead of the raw coal and the coal slurry in which the solvent is mixed, the direct coal liquefaction reaction tower 10 is used instead.
It is also possible to supply the coal to a coal liquefaction reaction. In this case, addition conditions and reaction conditions can be set in the same manner as in the case where the above-mentioned catalyst is supplied to the coal liquefaction reaction tower 10 in the state of coal slurry.

Subsequently, the product obtained by the coal liquefaction reaction is sent to the high temperature separator 17 through the pipe 18 in the same manner as in the conventional method, and the product gas (including the high pressure gas) is supplied to the high temperature separator 17. water and Keichu quality oil (typically C ₅ to 2
Components consisting of boiling point fractions below 60 ° C) and heavy oil (usually 2
It is separated into a component consisting of a boiling point fraction of 60 ° C. or higher) and a residue. Of these, the components consisting of the produced gas, water and light and medium oil are passed through the pipe 21 and through the pressure reducing valve to the atmospheric distillation column 1.
9 and is separated into product gas, water and light / medium oil components, and separated and collected by a product gas collector 23, a light / medium oil collector 24 and a water collector 25.

Here, the reducing gas recovered together with the produced gas can be recycled for further separation and purification.

Further, the above light-to-medium component is usually used in light oil (usually a boiling point fraction of C _{5 to} less than 220 ° C.) and medium oil (usually a boiling point fraction of 220 to less than 260 ° C.), if necessary. It can be separated by the distillation operation and recovered as a predetermined product oil.

On the other hand, the components consisting of the heavy oil and the residue are sent to the vacuum distillation column 20 through the pressure reducing valve through the pipe 22, and the vacuum distillation column 20 performs vacuum distillation (10 to 80 torr).
Those having a boiling point fraction of 538 ° C. or higher are discharged to a residue collector 29 through a pipe 31 and removed as a liquefaction residue.

On the other hand, the heavy oil having a boiling point of less than 260 to 538 ° C. is once returned to normal pressure, and then a high pressure pump (not shown) and a heater (not shown) provided on the pipe 32 path. ) Is kept under high temperature and high pressure, and Ni on the alumina carrier.
The hydrogenation reaction column 30 is sent to a fixed bed hydrogenation reaction column 30 filled with a material carrying a —Mo catalyst or a Co—Mo catalyst, and the hydrogenation reaction column 30 is usually under a hydrogen atmosphere at 270 to 380 ° C. and 80 to 120 atm. In general, LHSV is reacted with hydrogen gas for 1 to 2 hours to carry out a hydrogenation reaction, whereby a hydrogenation solvent composed of a component such as tetralin and having an increased hydrogen donating property can be produced. The obtained solvent is pipe 33
It is circulated and used as a coal liquefaction solvent by returning to the solvent storage tank 3 through.

[0062]

EXAMPLES Examples of the present invention will be described below.

Example 1 A coal liquefaction reaction was carried out using the coal liquefaction apparatus 1 used in the coal liquefaction method according to the present invention shown in FIG.

In the present Example 1, bituminous coal was pulverized to a particle size of 150 μm or less (yield 80%) using a rod mill pulverizer and the properties of three types (A coal, B coal and C coal, each coal type) are shown in Table 1. Liquefaction was performed using 10 t of each of the raw material coals shown in FIG. In each of the liquefaction reactions, the raw material coal in the coal storage tank 2 is first passed through the pipe 5, the coal-based solvent (including tetralin) in the solvent storage tank 3 is passed through the pipe 6, and the yield of the catalyst storage tank 4 is 16 μm or less. Is 90
% Of the particles of the synthetic iron sulfide catalyst are sent to the coal slurry preparation tank 9 (in the tank; reducing gas atmosphere, 60 ° C., 1 atm) through the pipe 7 and mixed by the stirrer 8 so that the coal slurry concentration is the same as that of the raw coal. A coal slurry was prepared in which the weight ratio of the solvent to the dry weight (solvent / raw coal) was 1.5 and the amount of the catalyst added to the coal slurry was 3% by weight based on the dry weight of the raw coal particles.

Subsequently, the coal slurry obtained in the coal slurry preparation tank 9 is conveyed from the coal slurry preparation tank 9 through the pipe 11 at a constant speed by the circulation pump 41 while the radiation irradiation device 42 (inside the device; at room temperature, 1 atm, piping 11
Valve; until the irradiation of the coal slurry with a radiation dose of 10 ⁶ roentgen was performed.
Was closed and returned to the coal slurry preparation tank 9 through the pipe 44 and circulated (since the radiation device described below was used, 3
A predetermined radiation dose could be applied by circulating the coal slurry 0 to 40 times). By repeating the circulation, all the coal slurry obtained in the coal slurry preparation tank 9 is 10 ⁶
When the radiation dose of X-ray was irradiated, the irradiation of radiation was stopped, the valve 43 was opened to the high pressure pump 12 so that the coal slurry could flow, and the coal slurry was sent to the liquefaction reaction system through the high pressure pump 12.

The radiation irradiating device 42 of this embodiment is provided with a cylindrical fixing device which is concentrically shielded by lead around the pipe 11 and does not leak radiation to the outside. A window through which only γ-rays are transmitted is provided only on the inner peripheral part of the container, the fixing device is loaded with a cobalt 60 radiation source, and the coal slurry, which is the irradiation target, is passed through the pipe 11 to obtain 10 ^A device capable of irradiating a radiation dose of ¹⁰ roentgen was used.

Next, the coal slurry is transferred to the switching valve 4
3 is switched to be sent to a high-pressure pump 12 which is a plunger type slurry pump, and the coal slurry is sucked and compressed by the plunger of the high-pressure pump 12 to a pressure of 170 atm and becomes a piston flow to form a coal liquefaction reaction tower. Supplied to 10. At that time, the hydrogen storage tank 13
The hydrogen of (1) was made into a high pressure hydrogen gas of 170 atm (hydrogen gas purity of 99% or more) by a compressor, and this was supplied into the system to make a hydrogen atmosphere. In addition, 40 by the heater 16
After being heated to 0 ° C., the coal liquefaction reaction tower 10 (inside the tower; 4
Slurry charging rate 100 to 110 kg / hr (reaction tower residence time 60) under hydrogen atmosphere at 50 ° C. and 170 atm.
Min) and reacted with the hydrogen atmosphere gas to carry out hydrocracking.

Subsequently, the product obtained by the above coal liquefaction reaction is sent to the high temperature separator 17 through the pipe 18.
In the high-temperature separator 17, the product gas, water, and light and medium-grade oil (boiling point of C _{5 to} less than 260 ° C.) were separated into components and heavy oil and components consisting of residues. Of these, the components consisting of generated gas, water and light medium oil are decompressed through a pipe 21 and then sent to an atmospheric distillation column 19 where they are separated into generated gas, water and light medium oil (liquefied oil) components and generated. Gas collector 23, light and medium oil collector 24, and water collector 25
Was collected separately. Here, the hydrogen-containing gas recovered together with the produced gas was further separated and purified, and then circulated and used as a recycled hydrogen gas.

On the other hand, heavy oil (boiling point above 260 ° C.)
The components consisting of the residue and the residue are depressurized through a pipe 22, and then sent to a vacuum distillation column 20 and subjected to vacuum distillation (reduced pressure to 10 to 50 torr) in the vacuum distillation column 20 to liquefy those having a boiling point of 538 ° C. or higher. The residue was discharged to the residue collector 29 through the pipe 31 and removed.

On the other hand, the heavy oil having a boiling point of less than 260 to 538 ° C. is once returned to normal pressure, and then a high pressure pump (not shown) and a heater (not shown) provided on the pipe 32 path. ) Is sent under high temperature and high pressure to a fixed bed hydrogenation reaction column 30 filled with a Ni—Mo catalyst, and the hydrogenation reaction column 30 is usually heated to 300 to 380 ° C. and 80 to 120 atm under a hydrogen atmosphere. In this, LHSV was reacted with hydrogen gas for 1 hour to carry out a hydrogenation reaction, thereby producing a coal-based solvent composed of a component containing tetralin or the like having an improved hydrogen donating property. The obtained solvent was circulated and used as a coal liquefaction solvent by returning it to the solvent storage tank 3 through the pipe 33.

The above three types (coal A, coal B and coal C) of raw material coal were used to liquefy each of the coals by 10 tons, and the yields of the resulting liquefied oil (light medium oil) were calculated. . From the obtained results, FIG. 3 shows a graph showing the liquefied oil yield for each coal type.

Comparative Example 1 A coal liquefaction reaction was carried out using the coal liquefaction apparatus 51 used in the conventional coal liquefaction method shown in FIG.

In this Comparative Example 1, bituminous coal was pulverized to a particle size of 150 μm or less (yield 80%) using a rod mill pulverizer, and the properties of three types (A coal, B coal and C coal, each coal type) are shown in Table 1. Liquefaction was performed using 10 t of each of the raw material coals shown in FIG. In each of the liquefaction reactions, the raw material coal in the coal storage tank 2 is first passed through the pipe 5, the coal-based solvent (including tetralin) in the solvent storage tank 3 is passed through the pipe 6, and the yield of the catalyst storage tank 4 is 16 μm or less. Is 90
% Of the particles of the synthetic iron sulfide catalyst are sent to the coal slurry preparation tank 9 (in the tank; reducing atmosphere, 60 ° C., 1 atm) through the pipe 7 and mixed by the stirrer 8 so that the coal slurry concentration is the dryness of the raw coal. A coal slurry was prepared in which the weight ratio of the solvent to the weight (solvent / raw coal) was 1.5 and the amount of the catalyst added to the coal slurry was 3% by weight based on the dry weight of the raw coal particles.

Next, the coal slurry is sent to a high-pressure pump 12 which is a plunger type slurry pump, and the coal slurry is sucked and compressed by the plunger of the high-pressure pump 12 so as to have a pressure of 170 atm and a piston. It becomes a flow and is supplied to the coal liquefaction reaction tower 10. At that time, the hydrogen in the hydrogen storage tank 13 was compressed by a compressor into a high pressure hydrogen gas of 170 atm (hydrogen gas purity 99
% Or more) and supply this into the system to make a hydrogen atmosphere. After being further heated to 400 ° C. by the heater 16, the coal liquefaction reaction tower 10 (inside the tower; 450 ° C., 170 atm) under a hydrogen atmosphere, the slurry charging rate 100 to 11
It was charged at 0 kg / hr (reaction tower residence time 60 minutes) and reacted with the hydrogen gas for hydrocracking.

Subsequently, the product obtained by the above coal liquefaction reaction is sent to the high temperature separator 17 through the pipe 18.
In the high-temperature separator 17, the product gas, water, and light and medium-grade oil (boiling point of C _{5 to} less than 260 ° C.) were separated into components and heavy oil and components consisting of residues. Of these, the components consisting of the generated gas, water and light medium oil are decompressed through the pipe 21 and then sent to the atmospheric distillation column 19, where they are separated into the generated gas, water and light medium oil (liquefied oil) components and generated. Gas collector 23, light and medium oil collector 24, and water collector 25
Was collected separately. Here, the hydrogen-containing gas recovered together with the produced gas was further separated and purified, and then circulated and used as a recycled hydrogen gas.

On the other hand, heavy oil (boiling point above 260 ° C.)
After being decompressed, the components consisting of the residue and the residue are sent to the vacuum distillation column 20 through a pipe 22, and are subjected to vacuum distillation (reduced pressure to 10 to 50 torr) in the vacuum distillation column 20 to liquefy those having a boiling point of 538 ° C. or higher. The residue was discharged to the residue collector 29 through the pipe 31 and removed.

On the other hand, the heavy oil having a boiling point of less than 260 to 538 ° C. is once returned to normal pressure, and then a high pressure pump (not shown) and a heater (not shown) provided on the pipe 32 path. ) Is sent under high temperature and high pressure to a fixed bed hydrogenation reaction column 30 filled with a Ni-Mo catalyst, and the hydrogenation reaction column 30 is subjected to LHSV at 300 to 380 ° C. and 80 to 120 atm under a hydrogen atmosphere. For 1 hour, the hydrogenation reaction was carried out by reacting with hydrogen gas to produce a coal-based solvent composed of a component containing tetralin or the like having an improved hydrogen donating property. The obtained solvent was circulated and used as a coal liquefaction solvent by returning it to the solvent storage tank 3 through the pipe 33.

The above three types (coal A, coal B, and coal C) of raw material coal were used to liquefy each of the coals by 10 tons, and the yields of the obtained liquefied oil (light medium oil) were calculated. . From the obtained results, FIG. 3 shows a graph showing the liquefied oil yield for each coal type.

[0079]

[Table 1]

[0080]

In the coal liquefaction reaction of the present invention, the coal structure can be relaxed in advance by irradiating the coal slurry with radiation as a pretreatment of the liquefaction reaction, and thereafter,
It is possible to improve the efficiency of hydrocracking in the liquefaction reaction, which makes it possible to improve the desired liquefied oil yield even under mild conditions (lower temperature and lower pressure conditions than before).
Economical efficiency is improved.

The pretreatment portion for further irradiation is as follows:
It is close to normal temperature and pressure, and the process including the equipment required for it can be simplified, and it can be easily realized.

[Brief description of drawings]

FIG. 1 is a use state diagram schematically showing a configuration of an embodiment of a coal liquefaction apparatus used in a coal liquefaction method according to the present invention.

FIG. 2 is a schematic diagram showing an embodiment of a coal liquefaction apparatus in a coal liquefaction method disclosed as a prior art.

FIG. 3 is a graph showing a liquefied oil yield for each coal type.

[Explanation of symbols]

1, 51 ... Coal liquefier, 2 ... Coal storage tank, 3
… Solvent storage tank, 4… Catalyst storage tank, 5 ～
7, 11, 14, 18, 21, 22, 26-28, 31
~ 33, 44 ... Piping, 8 ... Stirrer,
9 ... Coal slurry preparation tank, 10 ... Coal liquefaction reaction tower,
12 ... High-pressure pump, 13 ... Hydrogen storage tank,
15, 43 ... Automatic valve, 16 ... Heater,
17 ... Separator, 19 ... Distillation column,
20 ... Vacuum distillation column, 23 ... Product gas collector,
24 ... Light and medium oil collector, 25 ... Water collector,
29 ... Residue collector, 30 ... Hydrogenation reaction tower,
41 ... Circulation pump, 42 ... Radiation irradiation device.

Claims (8)

[Claims] 1. A coal liquefaction method, which comprises irradiating a coal slurry in which raw material coal, a solvent and a catalyst are mixed, with radiation, and then performing a coal liquefaction reaction under high temperature and high pressure conditions in a reducing gas atmosphere. 2. The radiation dose due to irradiation is 10 ²
The coal liquefaction method according to claim 1, wherein the range is from ¹⁰ to 10 ¹⁰ roentgen. 3. The temperature during irradiation with radiation is 40 to 100 ° C.
And the pressure is 1 to 10 atmospheres. The coal liquefaction method according to claim 1 or 2. 4. The coal liquefaction method according to claim 1, wherein radiation is applied while circulating the coal slurry. 5. The concentration of the coal slurry is 1.0 in terms of the weight ratio of the solvent to the dry weight of the raw coal (solvent / raw coal).
The coal liquefaction method according to any one of claims 1 to 4, which is in the range of 4.0. 6. The coal liquefaction method according to claim 1, wherein the catalyst is fine particles of 16 μm or less and a yield of 90% or more. 7. The amount of the catalyst blended in the coal slurry is
The coal liquefaction method according to any one of claims 1 to 6, which is 0.5 to 5% by weight based on the dry weight of the raw material coal. 8. The coal liquefaction method according to claim 1, wherein the high temperature and high pressure conditions during the coal liquefaction reaction are a temperature of 400 to 500 ° C. and a pressure of 100 to 200 atm.