JPH1046163A - Production of highly concentrated porous coal slurry - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to produce a highly concentrated porous coal slurry at good heat efficiency and to simplify production equipment by adding a porous coal to a medium oil kept at a specified temperature and separating the highly concentrated slurry portion formed as a result of settlement. SOLUTION: While keeping a medium oil is being kept at a temperature of above the boiling point of water and below the initial boiling point of the oil, a porous coal is introduced into this oil. The coal is allowed to settle, and the formed highly concentrated slurry portion is separated. According to this process, the porous coal is dehydrated not by forming a slurry of the coal and a medium oil but by introducing it into a heated medium oil. The temperature of the heated oil is in the range of the boiling point of water to the initial boiling point of the oil. The reason why the temperature is specified to be above the boiling point of water is that the water in the porous coal can be boiled and evaporated thereby. The reason why the temperature is specified to be below the initial boiling point of the medium oil is that the evaporation of the oil itself can be prevented thereby.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for dehydrating porous coal, which is considered to be low-grade coal because it contains a large amount of water, by using high-temperature oil to obtain an excellent solid fuel. In particular, reduce the amount of oil used,
The present invention also relates to a method for producing a high-concentration porous coal slurry with improved energy efficiency. If oil is removed from the high-concentration porous coal slurry obtained here, it will be a solid fuel.

[0002]

2. Description of the Related Art Porous coal tends to contain a large amount of water, for example, as much as 30 to 70% by weight due to its porosity. For porous coal with such a high water content, for example, even if you try to transport it to an industrial area and use it, the transportation cost is relatively high because it is equivalent to transporting moisture, and it is used near Yamamoto The reality is that you have to do it. A typical example of such a high moisture content porous coal is lignite.

[0003] Some brown coals have favorable properties of low ash content and low sulfur, but as described above, their water content tends to be high due to their porosity, and the water content is 30%.
If it exceeds, the transportation cost becomes very expensive,
In addition, the calorific value per unit weight is reduced due to the higher water content. In addition to lignite, lignite and subbituminous coal have similar problems.

Accordingly, the case of lignite will be described below as a typical example, but the present invention is applied to all porous coals such as lignite and sub-bituminous coal. Also, as brown coal, there are Victoria coal, North Dakota coal, Berga coal, and the like, and any porous coal having a high water content is an object of the present invention regardless of the production place.

[0005] Conventionally, techniques for reducing the water content of lignite to use it as a solid fuel have been studied. Among the methods for removing water, dry evaporation dehydration methods such as a tubular dryer method (conventional methods) have been proposed. Law) and milling
A non-evaporative dehydration method (conventional method) such as a process is known.

However, the conventional tubular dryer method consumes a large amount of heat energy for drying, and the dry lignite produced is porous and has a large active surface area. There is a risk that a spontaneous ignition accident may occur due to the oxygen adsorption and oxidation reaction, and a practical problem that storage and transport properties are poor is pointed out.

In the conventional milling process, since high-pressure operation is performed, the cost of manufacturing and maintaining equipment suitable for this operation is high, and the high-pressure operation itself is difficult and complicated. In addition, this method has the problem of wastewater treatment. Further, the dewatering rate of the dewatered porous coal obtained by the conventional method is poor, and the suppression of spontaneous combustion is not sufficient.

On the other hand, as a method of suppressing spontaneous ignition, a method of compressing and forming porous coal to reduce the surface in contact with air (conventional method), covering the surface of porous coal with tar, asphalt, mineral oil, etc. A method for preventing contact with air (conventional method) has been proposed.

Thus, for example, a safe lignite briquette production method free from danger of ignition has been proposed by combining the above-mentioned conventional methods with the conventional method. Therefore, there is a problem that the thermal efficiency is low, and in addition, there is also a problem that it is difficult to say that the suppression of spontaneous ignition has been completely achieved.
As a further alternative, as a method of obtaining a dehydrated porous coal by adding the above-mentioned conventional method after dehydration by the above-mentioned conventional method,
The following methods have been proposed.

Japanese Patent Publication No. 63-61358 (conventional method-1): Spraying a mixture of aromatic hydrocarbon and asphalt onto lignite which has been dehydrated in advance to prevent dust generation and increase calories, to coat the lignite particle surface Technology.

[0011] Japanese Patent Publication No. 7-47751 [Japanese Translation of PCT International Publication No. 63-503461] (Conventional method-2): Low-grade lump coal crushed to 0.5 to 1.5 inches is immersed in oil and heated to produce steam. And replacing the oil with oil, while separating the lump coal while the steam is still being released from the coal, and removing the oil from the wet lump coal, the lump coal being coated with residual oil. It is in a state where spontaneous combustion is suppressed. JP-A-61-238889 (Conventional method-3): Lignite is dry-distilled and reformed, and the generated lignite is coated with tar generated.

However, the above-mentioned conventional methods 1 to 3 all have a high energy intensity and are complicated in operation, and the above-mentioned conventional method 1 often results in non-uniform asphalt coating, thus suppressing spontaneous ignition. There remain problems such as an insufficient effect. Therefore, as a new manufacturing method for solving these problems, the invention of Japanese Patent Application Laid-Open No. 7-233383 was proposed (conventional method).

In the conventional method, a slurry is prepared by stirring and mixing porous coal and a medium oil, and the slurry is mixed with a slurry of 100 to 250%.
C. to evaporate and separate the water in the porous coal, followed by solid-liquid separation to obtain a dehydrated solid fuel. The medium oil used in the conventional method is obtained by dissolving heavy oil such as asphalt in the medium oil, and only the heavy oil in the medium oil is selectively left on the porous coal in the solid-liquid separation. Such a small amount (5% by weight or less) of heavy oil effectively suppresses spontaneous ignition of the porous coal.

This conventional method is also a method in which the surface of the porous coal is covered with oil to prevent contact with air, as in the above-described conventional method. The good point of the conventional method is that the heavy oil is oxidized. Since it is particularly selectively adsorbed to active sites having high reactivity, high coating efficiency can be improved even with a small amount of oil. In addition, in the conventional method, the vapor of the water vaporized and separated from the porous coal is heated to a high temperature by compressing and raising the temperature to serve as a heating source in the above-mentioned dehydration step.

[0015] On the other hand, from the viewpoint of a method of treating coal in a slurry state, (a) the ground coal is brought into contact with a medium oil, and this is mixed while applying a shearing force by, for example, stirring, to form a uniform oil. A method of obtaining a slurry, or (b) first contacting coarsely pulverized coal with a medium oil, forming a mixture by stirring or the like in the same manner as described above, and further pulverizing the coal with a ball mill or the like to obtain a uniform slurry Is adopted.

In the above-mentioned conventional method, a slurry is prepared by charging a pulverized porous coal and a medium oil into a tank and stirring and mixing to prepare a slurry.

[0017]

In the above conventional method, as described above, after a mixed slurry of dehydrated porous coal and medium oil is obtained, solid-liquid separation is finally performed to remove the medium oil from the slurry. A solid fuel is obtained, and as a method of the solid-liquid separation, a medium oil removing method by centrifugation, heating, or the like is performed. In such solid-liquid separation, it is more advantageous to remove the medium oil from the high-concentration slurry to obtain a solid fuel than to remove the medium oil from the low-concentration slurry from the viewpoint of equipment and energy used. Therefore, development of a method for obtaining a highly concentrated slurry with high efficiency is desired.

However, in the above conventional method,
The proportion of water in the volume of the raw water-rich porous coal is high. For example, in the case of brown coal containing 65% by weight of water, about 72%
Because it contains a large amount of water by volume, it is difficult to prepare a high-concentration slurry when mixing and preparing a raw material slurry of raw material porous coal and medium oil. It was necessary to prepare a raw material slurry. Therefore, the slurry after dehydration has been obtained as a low-concentration slurry having a large amount of medium oil.

When such a large amount of medium oil is used,
As described above, not only does a large amount of energy be required for solid-liquid separation, but also a large amount of heat is consumed when the raw slurry is heated to dehydrate the porous coal, and thus the thermal efficiency is reduced. In addition, there is a problem that the porous coal is separated in the slurry and the slurry tends to be non-uniform.

In addition, since the conventional method employs a method in which the raw material is slurried and then heated, it is necessary to perform indirect heating with a heat exchanger or the like. There is a problem in handling, such as that the slurry in the exchanger) tends to be non-uniform. There is also a problem that the equipment becomes complicated.

The present invention has been made in view of the above-mentioned problems, and uses a porous coal as a raw material to finally obtain a solid fuel which is suppressed in spontaneous combustion and has excellent storage and transport properties. More specifically, it is an object of the present invention to provide a method capable of producing a high-concentration porous coal slurry with high thermal efficiency and simplifying a production facility for the high-concentration porous coal slurry. Aim.

[0022]

The method for producing a high-concentration porous coal slurry according to the present invention is characterized in that the medium oil is maintained at a temperature not lower than the boiling point of water and not higher than its initial boiling point. The gist is to introduce porous coal, settle the porous coal, and separate a portion of the high-concentration slurry.

In the method of the present invention, dehydration is performed by charging the porous coal into the heated medium oil without using the porous coal as a slurry mixed with the medium oil. The heating temperature of the medium oil is, as described above, a temperature equal to or higher than the boiling point of water and equal to or lower than the initial boiling point of the medium oil. The reason for setting the medium oil below the initial boiling point is to prevent the medium oil itself from evaporating.

When the porous coal is charged into the medium oil maintained at such a temperature, the moisture contained in the porous coal boils, so that the particles of the porous coal move violently in the medium oil. The heat is efficiently transferred from the medium oil to the porous coal, and the contained water evaporates one after another, and the dehydration proceeds.

In the porous coal from which most of the water has been removed by evaporative separation in this manner, since the boiling phenomenon of the water is eliminated, the movement becomes slow and the water sediments downward. Where the porous coal has settled and deposited, a high-concentration slurry of porous coal and medium oil has been formed, and a high-concentration slurry can be obtained by collecting the sedimented and deposited portion. Thereafter, if the medium oil contained in the high-concentration slurry is recovered, a solid fuel with reduced spontaneous combustion can be obtained.

The medium oil is 10 ° C. below the boiling point of water.
Those showing a high initial boiling point are preferred. In the case of a medium oil having a low initial boiling point, the medium oil evaporates simultaneously with the boiling of water, and the lower the initial boiling point, the larger the amount of evaporation of the medium oil. Therefore, it is preferable that the initial boiling point is higher, and that the above-mentioned initial boiling point is preferable. More preferably, it has an initial boiling point 30 ° C. or more higher than the boiling point of water.

Even if the initial boiling point of the medium oil as a whole shows a low value, any medium oil containing a component having a boiling point higher than the boiling point of water can be used. The evaporation reduces the thermal efficiency of the entire manufacturing apparatus.

Further, the medium oil preferably has a density at 20 ° C. of 1.1 or less. In order to complete the dehydration and settle the porous coal in the medium oil, the porous coal must have a higher density than the medium oil. Since the true density of porous coal is generally around 1.4, it is preferable to use a medium oil having a density at 20 ° C. of 1.1 or less, as described above, in order to sediment it satisfactorily. More preferably, the medium oil has a density of 1.0 or less at 20 ° C. As the medium oil, petroleum hydrocarbon oil is recommended.

It is more preferable that the medium oil is a hydrocarbon oil containing 10% by weight or less of heavy oil. Examples of the heavy oil include coal-based heavy oils such as petroleum asphalt and coal tar, petroleum-based distillation residues, and coal-based distillation residues. As the medium oil, these heavy oils are mixed with other hydrocarbon oils. Or a hydrocarbon oil originally containing these heavy oil components.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Example> FIG. 1 is a conceptual diagram showing an example of an apparatus for carrying out a method for producing a high-concentration porous coal slurry according to the present invention. The container 1 has a structure in which an upper cylinder 11 and a lower cylinder 12 having a smaller diameter than the upper cylinder 11 are connected by an upper cone 13 having an inclination. At the bottom of the lower cylinder 12,
The lower cone portion 14 having an inclination is connected, and the settled solids are collected and accumulated by the lower cone portion 14 to thereby concentrate the slurry, and the bottom of the lower cone portion 14 has a slurry outlet 16. Is connected. A pipe 15 for heating the medium oil is passed through the upper cylinder 11.

As a production method, first, a container 1 containing a hydrocarbon oil (medium oil) heated to a temperature higher than the boiling point of water is used.
Then, porous coal pulverized to 5 mm or less is charged. The heating temperature of the medium oil is a temperature not lower than the boiling point of water and not higher than the initial boiling point of the medium oil, preferably not lower than 10 ° C. than the boiling point of water and not higher than the initial boiling point of the medium oil. , More preferably at least 30 ° C. above the boiling point of water and at most the initial boiling point of the medium oil. The boiling point of water is, for example, 143.5 ° C. when dehydrating at 400 kPa (about 4 atm). In this case, it is preferable to heat the medium oil to 175 ° C.

Incidentally, in order to increase the contact area with the medium oil, it is desirable to pulverize the porous coal in advance, and the size of the pulverized porous carbon particles is preferably 5 mm or less as described above. , More preferably about 3 mm or less.

At the liquid level of the medium oil in the upper cylinder 11, the porous coal in contact with the high-temperature oil is rapidly heated, and the contained water rapidly starts to boil and evaporate. Due to this boiling, the particles of the porous coal move irregularly and vigorously in the medium oil, and disperse the medium oil while stirring it. As a result, the contact between the high-temperature medium oil and the porous coal is remarkably promoted, high heat transfer is obtained, and the boiling evaporation of water proceeds efficiently.

As the evaporation of water progresses in this way and the amount of evaporation gradually decreases, the movement of the porous coal gradually becomes slower. Settles inside. The sedimented porous coal particles collect in the lower cylinder 12 of the container 1 and are concentrated to form a high-concentration slurry. The porous coal forming the high-concentration slurry is a dewatered porous coal in which water is almost evaporated, and is further compacted by being deposited on the bottom of the lower cylinder 12.

The condensed dehydrated porous coal is withdrawn as a slurry from the outlet 16 at the bottom of the container 1.
In this way, a dehydrated high-concentration porous coal slurry is obtained.

Thereafter, the high-concentration porous coal slurry is sent to the medium oil recovery step 4 by the pump 2, where the medium oil is recovered, and the medium oil is again charged into the container 1 for circulating use. Further, the medium oil is newly replenished as the amount of the medium oil which is taken out and becomes insufficient with the product (porous coal).

When the medium oil is charged into the container 1,
It is desirable that the liquid be introduced so as to form a circulating flow near the liquid level in the container 1. Porous coal tends to rise to the surface of the liquid,
Since the heat transfer to the porous coal floating on the liquid surface is low in this way, in order to prevent this, the porous coal is pushed into the liquid by the circulating flow formed as described above. By forming a circulating flow in this way, moisture evaporation from the porous coal proceeds more efficiently. On the other hand, the dewatered porous coal from which most of the medium oil has been removed in the medium oil recovery step 4 becomes an excellent solid fuel with reduced spontaneous combustion.

In the apparatus shown in FIG. 1, steam generated from porous coal in the vessel 1 is supplied to the pipe 1 on the upper cylinder 11.
7, the temperature is increased by compression by the compressor 3, and is used for heating the medium oil by passing through the pipe 15.
Next, the remaining heat is used in the heat exchanger 18 for heating the medium oil replenished to the container 1, and the steam is discharged as water.

If the amount of heat is insufficient only by heating in the heat exchanger 18, the medium oil is heated by a heat medium such as hot oil in the heat exchanger 19, and the amount of heat is replenished in this manner. The temperature inside the container 1 can be maintained at a desired temperature.

<Second Example> FIG. 2 is a conceptual diagram showing another example of an apparatus for carrying out the method for producing a high-concentration porous coal slurry according to the present invention. It is to be noted that the same components as those in FIG.

A blade 25 is provided in the upper cylinder 21 of the container 10 in parallel with the upper cone 13. The sedimented porous coal is supplied to the blade 25 and the upper cone 1.
3 does not penetrate, so that a fining layer of only the medium oil is formed here. A pipe 26 is connected to the fining layer so that a medium oil containing no porous coal can be extracted.

As in the first example, the porous coal charged into the heating medium oil is evaporated and dehydrated, and settles in the lower cylinder 12.
It is concentrated and becomes a dehydrated high-concentration porous coal slurry, which is extracted from the extraction port 16.

The steam generated from the porous coal in the vessel 10 is introduced into the pipe 17 on the upper cylinder 21 and
After the temperature is increased by compression, it is used for heating the medium oil in the heat exchanger 27, further used for heating the medium oil in the heat exchanger 29, and then discharged.

To the medium oil recovered from the high-concentration dehydrated porous coal slurry in the medium oil recovery step 4, an insufficient amount of medium oil (or a specific component insufficient from medium oil) is added. Is heated. Next, the medium oil extracted from the pipe 26 is added, and further heated in the heat exchanger 27. When the temperature of the medium oil is low, the medium oil is heated by the heat medium in the heat exchanger 28,
In this way, the temperature in the container 10 is maintained at a desired temperature.

In the above-mentioned second example, the flow rate of the circulating medium oil can be arbitrarily set by extracting the medium oil from the fining layer. If it is desired to raise the temperature in the container 10, the medium oil to be charged needs to be heated to a high temperature. However, if the medium oil is made extremely high, the medium oil will evaporate. is there. However, when the amount of circulating medium oil can be set arbitrarily as in the second example, the temperature of the medium oil in the container 10 can be controlled by increasing the amount of circulating medium oil. In addition, by increasing the amount of circulating medium oil, the floating of the porous coal on the liquid surface can be more effectively suppressed. In this way, the temperature of the medium oil can be freely controlled,
It becomes easy to control the flow state of the porous coal and the medium oil at the top of the plate.

On the other hand, in the first example, the amount of the circulating medium oil is determined by the concentration of the slurry extracted from the extraction port 16 and the medium oil recovery rate in the medium oil recovery step 4. There is no flexibility in the amount of circulating medium oil. Therefore, there are some restrictions on the temperature control in the container 1,
The control of the flow state at the top of the container 1 is also limited.

In the first example, since the long pipe 15 is passed through the container 1, this obstructs the sedimentation of the porous coal and complicates the apparatus. Is advantageous without such a thing.

On the other hand, in terms of thermal efficiency, in the first example, heat is directly supplied by the pipe 15, which is advantageous in terms of thermal efficiency. In contrast, the second
In the case of the example, since the heat exchanger is used, the heat recovery is slightly inferior. That is, the first example is advantageous in terms of thermal efficiency, and the second example is not complicated in device design and easy to operate, and has respective advantages.

The apparatus used in the present invention is not limited to the first and second examples, but has a dehydrating section at the upper part for bringing the raw water-containing porous coal into contact with the medium oil, and a lower part at the lower part. Any device may be used as long as it has a function of concentrating the settled dehydrated porous coal and discharging the same as a slurry.

The amount of medium oil required to handle the slurry after dewatering is quite small. The reason is that the brown coal shrinks during the dehydration process, and that the medium oil does not penetrate into the micropores from which water has been removed. For example, including medium oil impregnated in lignite,
It can be concentrated to dry coal / medium oil = about 50/50 (weight ratio). In addition, excluding the medium oil impregnated in the lignite, the weight ratio of the medium oil and the dry coal actually contributing to the flow is as follows: dry coal / medium oil = about 50/19
And a slurry with a very high concentration can be obtained.

On the other hand, when a slurry is formed from the beginning as in the conventional method, a large amount of oil is required due to the presence of water in the porous coal.
wt%) and heavy oil A (medium oil) to form a slurry, the ratio of the highest concentration is raw brown coal / heavy oil A = 60.
/ 40 (weight ratio) [dry coal / heavy oil A = 21/40], and the concentration is about 54 vol%. The slurry at this concentration has a high viscosity, and it is difficult to achieve a higher concentration. Therefore, when the raw material is first slurried as in the conventional method, it cannot be handled in the dehydration step at a concentration higher than the above concentration.

On the other hand, in the present invention, since the slurry is not formed at the time of dehydration, the amount of medium oil at the time of dehydration can be small,
In addition, the settled dewatered slurry can be made to have a high concentration as described above, so that the amount of medium oil used as a whole can be reduced. That is, in the case of the conventional method in which the slurry is first formed, it is necessary to use a large amount of the medium oil as described above, but in the case of the present invention, the amount of the medium oil handled in the dewatering step and the recovery step is greatly reduced. can do.

[0053]

【Example】

<Example 1> 1 mm of Morwell lignite containing 65 wt% moisture
It was ground to the following. 100 parts of heavy oil A (medium oil) in the vessel was kept at 130 ° C., and 10 parts of the above crushed Morwell lignite was charged into the heavy oil A. After the moisture of the lignite was boiled off and settled naturally at the bottom of the vessel, the lignite at the bottom was recovered in a slurry state. The time required for most of the lignite to settle was 5 to 10 minutes.

The lignite concentration of the recovered slurry was measured. Further, the slurry was centrifuged at 400 G to remove the adhering medium oil, and the moisture remaining in the lignite and the amount of the medium oil were determined.

<Example 2> As in Example 1, Morwell lignite containing 65% by weight of water was pulverized to 1 mm or less.
As the medium oil, a solution prepared by dissolving 20 parts of asphalt in 80 parts of A heavy oil was used, and the medium oil was kept at 130 ° C. in a container, and 10 parts of the crushed Morwell lignite was added to the medium oil in the same manner as in Example 1 above. , And the water was boiled off and evaporated, and the brown coal spontaneously settled at the bottom of the vessel was recovered in a slurry state. The lignite concentration of the recovered slurry was measured in the same manner, and the amount of water and medium oil remaining in the lignite was determined.

<Comparative Example 1> 100 parts of pulverized Morwell lignite (containing 65 wt% of water) and 100 parts of Fuel Oil A were mixed to form a slurry, and the mixture was heated with stirring at normal pressure until the slurry temperature reached 110 ° C. The water was evaporated by heating for about 3 hours. After the completion of the dehydration, the brown coal concentration of the slurry was measured. The slurry was centrifuged at 400 G to remove adhering medium oil to recover lignite, and the amount of water and medium oil remaining in the lignite was determined.

Comparative Example 2 100 parts of pulverized Morwell lignite (containing 65% by weight of water) and 100 parts of medium oil obtained by dissolving 20 parts of asphalt in 80 parts of Fuel Oil A were mixed to form a slurry. Similarly, evaporate the water,
The lignite concentration of the slurry was measured, and the amounts of water and medium oil remaining in the recovered lignite were determined.

Comparative Example 3 150 parts of pulverized Morwell lignite (containing 65 wt% of water) and 100 heavy oil A (medium oil)
The water was evaporated and the lignite concentration of the slurry was measured, and the amounts of water and medium oil remaining in the recovered lignite were determined, as in Comparative Example 1.
In the case of Comparative Example 3, the amount of the medium oil was insufficient at room temperature during the water evaporation, and it was difficult to make a uniform slurry. However, a uniform slurry was prepared by heating to 60 ° C. did it.

<Results> The results of Examples 1 and 2 and Comparative Examples 1 to 3 are shown in Table 1 below. The amounts of moisture and medium oil remaining in the dehydrated lignite are indicated by weight (kg) per 100 kg of dry lignite. Note that the amount of the medium oil in the recovered slurry includes the medium oil component (residual medium oil) impregnated in the lignite.

[0060]

[Table 1]

As can be seen from Table 1, high concentration slurries were obtained in Examples 1 and 2 as compared with Comparative Examples 1 to 3 in which the slurry was dehydrated. In addition, Comparative Examples 1 to 3 can be further concentrated by static separation or the like.

Regarding the degree of dehydration, Examples 1 and 2 were sufficiently dehydrated, and could be dehydrated better than Comparative Examples 1 to 3. Regarding the medium oil remaining in the lignite, Examples 1 and 2 have less residual medium oil than Comparative Examples 1 to 3,
Therefore, it can be seen that Examples 1 and 2 can satisfactorily dewater while leaving a small amount of medium oil.

[0063]

In the method for producing a high-concentration porous coal slurry according to the present invention, the raw material porous coal is efficiently dehydrated,
A high-concentration porous coal / medium oil slurry can be obtained. In addition, the total amount of medium oil used in this production method can be reduced, and therefore, the equipment can be simplified, for example, the number of high viscosity slurry pumps used can be reduced, and the energy efficiency can be significantly improved. Can be.

As described above, the dewatered porous charcoal slurry is used to remove dehydrated porous charcoal (solid fuel) after removal of the medium oil on the surface. However, in the case of a highly concentrated slurry, the removal of the medium oil is reduced. It is effective to obtain a high-concentration porous coal slurry as in the present invention because it can be easily performed with a small facility with energy. Moreover, the dewatered porous coal from which the medium oil has been removed is a good solid fuel in which spontaneous combustion is suppressed. If the medium oil contains heavy oil, removing the medium oil from the high-concentration slurry leaves only heavy oil in the dewatered porous coal. Dewatered porous coal in which oil is selectively left is also a good solid fuel with spontaneous ignition suppressed.

In the present invention, unlike the conventional method,
Because lignite is directly injected into medium oil held at high temperature,
There is no heat loss, and the particles move violently when the water boils, and can be dispersed with the circulating medium oil.
There is no need for equipment such as stirring.

The porous coal particles whose boiling has stopped are
Since the sediment is automatically settled and concentrated, it is possible to omit the conventional concentration and separation step, further simplify the equipment, and improve the energy efficiency.

Further, in the present invention, since the temperature rise of the porous coal particles and the boiling of water occur rapidly, the amount of medium oil impregnated in the brown coal after dehydration is reduced, and therefore the amount of medium oil consumed is reduced. can do. It is difficult to mechanically recover the medium oil impregnated in the porous coal, and most of the medium oil is evaporated and recovered. Load is reduced, which contributes to improving energy efficiency.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an example of an apparatus for implementing a method for producing a high-concentration porous coal slurry according to the present invention.

FIG. 2 is a conceptual diagram showing another example of an apparatus for performing the method for producing a high-concentration porous coal slurry according to the present invention.

[Explanation of symbols]

 1,10 container 2 pump 3 compressor 4 medium oil recovery process 11,21 upper cylinder 12 lower cylinder 13 upper cone section 14 lower cone section 15,17,26 pipe 16 extraction port 18,19,27,28,29 heat exchange Vessel 25 wing

Claims (4)

[Claims] 1. A method in which porous coal is present in a medium oil while maintaining the medium oil at a temperature not lower than the boiling point of water and not higher than its initial boiling point, and the porous coal is settled in the medium. A method for producing a high-concentration porous coal slurry, comprising separating a generated high-concentration slurry portion. 2. The method for producing a high-concentration porous coal slurry according to claim 1, wherein the medium oil has an initial boiling point higher than the boiling point of water by 10 ° C. or more. 3. The method for producing a high-concentration porous coal slurry according to claim 1, wherein the medium oil is a hydrocarbon oil having a density at 20 ° C. of 1.1 or less. 4. The method for producing a high-concentration porous coal slurry according to claim 1, wherein the medium oil is a hydrocarbon oil containing 10% by weight or less of heavy oil.