JP2000290673A - Modified low-grade coal, its production and coal-water slurry - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a modified low-grade coal that can be allowed to contain a large amount of low-grade coal and can give high-calorie low-grade coal CWM(coal-water mixture of low-grade coal) slurry. SOLUTION: Low-grade coal with particle sizes of <=3 mm is mixed with petroleum lightweight crude oil having average boiling of 150-300 deg.C and the resultant slurry is heated to be dewatered in the oil, and simultaneously the low-grade coal is impregnated with the petroleum lightweight crude oil. Then, the resultant slurry is subjected to the solid-liquid separation so that the content of the petroleum lightweight crude oil remaining in the low-grade coal may be adjusted to 1-10 mass % based on the mass of the anhydrous low-quality coal, thereby, the objective modified low-grade coal is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a modified low-grade coal, a method for producing the same, and a coal-water slurry. More specifically, the present invention relates to a slurry mixture containing coal and water, To obtain low-grade coal-water slurry (hereinafter also referred to as low-grade coal CWM) using low-grade coal as the raw material coal which is the main raw material of coal-water slurry (hereinafter also referred to as CWM) used as In addition, a modified low-grade coal as a raw coal from which a high calorie low-grade coal CWM can be obtained, and a method for producing the same, and a coal mainly using a low-grade coal or a modified low-grade coal as a raw coal −
Water slurry (CWM) belongs to the technical field of high calorie CWM.

[0002]

2. Description of the Related Art Low-grade coal generally has a low degree of carbonization and contains a large amount of water due to its hydrophilicity. Therefore, such low-grade coal is converted to CWM (CWM using low-grade coal as raw material coal). The solid content concentration (coal concentration)
That is, if a large amount of low-grade coal is contained as coal, basic characteristics such as fluidity required for CWM cannot be secured. Therefore, only a small amount of coal can be contained. From the viewpoint of securing basic characteristics such as fluidity, the maximum amount of coal that can be contained (hereinafter referred to as C
The highest concentration of coal in the WM. When the coal is specified as low-rank coal, it is also referred to as the highest concentration of low-rank coal in CWM. ) Are low, inevitably not self-burning, have high transport fares per calorie,
It has disadvantages such as low power generation efficiency, and low-grade coal is CWM
It has not been suitable for conversion.

[0003] Therefore, a method of obtaining a modified low-grade coal having a reduced water content by dehydrating the low-grade coal and having water repellency, and a technique related to converting the modified low-grade coal into CWM. Have been proposed.

[0004] However, in these methods, a hydrophilic functional group that is a source of hydrophilicity is eliminated, and tar components due to the carbonization effect are oozed on the surface. All of these methods utilize a chemical reaction. Process, the processing temperature is high,
Further, there are problems such as high wastewater pollution and high cost. On the other hand, there is an attempt to apply oil to low-grade coal in order to keep it physically, but low-grade coal, which is a fine powder with an extremely large specific surface area, can be effectively reformed by using a small amount of oil. There was the disadvantage that it could not be achieved. In addition, considering that not only the coal powder has a large surface area but also that the coal powder is pulverized again in a wet mill when producing CWM, the coal powder should be modified so that the water repellency is not lost by the re-pulverization. That is, it is necessary that the surface of the low-grade coal is essentially water-repellent before the regrinding, but not inside, but such a modification is achieved by a method of applying oil to the low-grade coal. There was a problem that it was not possible.

[0005] Furthermore, even if low-grade coal can be modified, poor fluidity due to the particle shape of low-grade coal implies
There is a problem that the maximum concentration of low-grade coal in CWM is suppressed to a slightly lower level, and CWM having a high-grade low-grade coal concentration cannot be obtained. In other words, the low-grade coal particles have a low fluidity because the physical shape includes many non-spherical particles such as a thread or a flat shape, and therefore, even if the low-grade coal is modified to some extent to have water repellency. Even if CWM (fluidization) is used, the fluidity is poor, and it is not possible to obtain CWM in which the concentration of low-grade coal is sufficiently high. In order to obtain a CWM having a sufficiently high concentration of low-rank coal, the fluidity needs to be improved.

[0006] As described above, regarding the low-rank coal CWM, it is impossible to increase the concentration of the low-rank coal (high concentration) with the conventional technology, and the maximum concentration of the low-rank coal in the CWM is low.
Therefore, the calories of low-rank coal CWM are low. Therefore, increasing the calorie of the low-rank coal CWM and increasing the concentration for this purpose have become the biggest bottleneck, that is, the problem.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances.
Modified low-grade coal capable of obtaining low-grade coal CWM having a high concentration of low-grade coal and high calories in WM, a method for producing the same, and low-grade coal or modified low-grade coal as raw material coal High calorie CWM using charcoal
(Coal-water slurry).

[0008]

In order to achieve the above object, a modified low-grade coal according to the present invention, a method for producing the same, and a coal-water slurry are provided.
And the method for producing a modified low-grade coal according to claim 2, and the coal-water slurry according to claims 3 to 7,
It has the following configuration.

That is, the modified low-grade coal according to claim 1 is characterized in that a slurry-like mixture containing a low-grade coal and a petroleum light oil having an average boiling point of 150 to 300 ° C. is heated to produce an oil of the low-grade coal. The dewatering is performed and the slurry mixture obtained by impregnating and adhering the petroleum light oil to the low-grade coal is separated by solid-liquid separation to adjust the content of the petroleum light oil remaining in the low-grade coal. A modified low-grade coal, wherein the low-grade coal has a particle size of:
3 mm or less, and the content of the petroleum light oil remaining in the low-grade coal is 1 to 10 with respect to the weight of the anhydrous low-grade coal.
It is a modified low-grade coal characterized by mass% (first invention).

[0010] The method for producing a modified low-grade coal according to claim 2 is characterized in that a low-grade coal having a particle size of 3 mm or less has an average boiling point of 150 to 30.
Mixing with 0 ° C. petroleum light oil to obtain a slurry-like mixture,
After heating the slurry-like mixture to dehydrate the low-grade coal in oil and impregnating and adhering the petroleum light oil to the low-grade coal, the slurry-like mixture is subjected to solid-liquid separation. A modified low-grade coal characterized by obtaining a modified low-grade coal in which the content of petroleum light oil remaining in the low-grade coal is adjusted to 1 to 10% by mass based on the weight of the anhydrous low-grade coal. This is a manufacturing method (second invention).

A coal-water slurry according to claim 3 is a coal-water slurry containing coal and water, wherein the coal is obtained by pulverizing the modified low-grade coal according to claim 1 or the modified low-grade coal. Coal characterized by being a modified low-grade coal
It is a water slurry (third invention).

The coal-water slurry according to claim 4 is a coal-water slurry containing low-grade coal and high-grade coal as coal, wherein the average particle size of the high-grade coal is less than that of the low-grade coal. A coal-water slurry characterized by being larger than the average particle size of the particles (fourth invention).

[0013] The coal-water slurry according to claim 5 is a coal-water slurry obtained by mixing a high-grade coal with a coal-water slurry containing low-grade coal as coal, wherein the average of particles of the high-grade coal is obtained. A coal-water slurry having a particle size larger than the average particle size of the low-grade coal particles (fifth invention).

According to a sixth aspect of the present invention, in the coal-water slurry, the low-grade coal is the modified low-grade coal according to the first aspect or a modified low-grade coal obtained by pulverizing the modified low-grade coal. It is a coal-water slurry according to 4 or 5 (sixth invention). The coal-water slurry according to claim 7 is the coal-water slurry according to claim 4, 5 or 6, wherein the amount of high-grade coal in the coal is 10 to 30% by mass (seventh invention).

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is implemented, for example, as follows. After coarsely pulverizing low-grade coal, it is sieved through a sieve having an opening diameter of 3 mm to obtain low-grade coal having a particle size of 3 mm or less. This is mixed with petroleum light oil having an average boiling point of 150 to 300 ° C. to obtain a slurry mixture. The slurry-like mixture is heated to 100 ° C. or more, for example, 130 ° C., and the low-grade coal is dewatered in oil to evaporate and remove water in the low-grade coal. After impregnating and adhering the light oil, the slurry mixture is subjected to solid-liquid separation. For example, the slurry mixture is centrifuged to obtain a solid content (low-grade coal containing petroleum light oil). , And the solid content is subjected to hot-air drying to remove oil, whereby the content of the petroleum-based light oil remaining in the low-grade coal is 1 to the mass of the anhydrous low-grade coal. ~ 10% by mass
To obtain modified low-grade coal. The average boiling point of oil is
It is the volume average boiling point, which is the boiling point averaged by volume. That is, the volume average boiling point (VABP). VABP =
_{(T 10 + t 30 + t} 50 + t 70 + t 100) / 5) is. t ₅₀
Is the 50% true temperature of the ASTM distillation temperature curve.

In this manner, the method for producing a modified low-rank coal according to the present invention is carried out, and the modified low-rank coal according to the present invention is obtained. The modified low-grade coal thus obtained is used as a coal raw material for CWM (coal-water slurry). That is, the modified low-grade coal is mixed with water, a surfactant, and the like, and pulverized to obtain a modified low-grade coal CWM.

[0017] The modified low-rank coal CWM is added to the CWM.
Mixing high-grade coal with a larger average particle size than the modified low-grade coal in the middle gives CWM in which the average particle size of the high-grade coal particles is greater than the average particle size of the modified low-grade coal particles .
In addition, the average particle diameter of the particles is a particle diameter that can equally divide the mass of the whole particles in a particle diameter distribution obtained by using, for example, Microtrack. That is, the weight average diameter.

Hereinafter, the function and effect of the present invention will be mainly described.

The low-grade coal is a coal having a low carbonization degree,
A coal having a / C ratio (atomic ratio between oxygen and carbon) of 0.15 or more, most of which have a water content of 25% or more and a fuel ratio (fixed carbon / volatile content) of 2.0 or less. It has been considered that low-grade coal is generally unsuitable for CWM because it has many oxygen-containing functional groups and is hydrophilic.

When CWM is converted from low-grade coal or the like, C
It is said that the maximum concentration of coal in the WM is correlated with the O / C ratio of the coal. It is known that when the O / C ratio is high, such as in low-grade coal, the maximum concentration of the coal in the CWM is extremely low. Have been. This is shown, for example, in FIG. Like this
Low-grade coal with a high / C ratio can be converted to C
Although it cannot be converted to WM, if even moisture can be reduced, C
It can be converted to WM and has good flammability.

According to the present invention, such low-grade coal is reformed and CW
The purpose of the present invention is to make it possible to obtain CWM in which the highest concentration of low-grade coal in M is high. First, the modified low-grade coal according to the present invention is, as described above, low-grade coal and the average boiling point: 150 to 30
The slurry-like mixture containing the petroleum light oil at 0 ° C. is heated to dehydrate the low-grade coal in oil, and the low-grade coal is impregnated with the petroleum light oil so as to be contained therein. A modified low-grade coal obtained by adjusting the content of petroleum light oil remaining in the low-grade coal by solid-liquid separation of the body, wherein the low-grade coal has a particle size of 3 mm or less, The content of the petroleum light oil remaining in the low-grade coal is 1 to 10% by mass based on the weight of the anhydrous low-grade coal (first invention). Further, as described above, the method for producing a modified low-grade coal according to the present invention comprises mixing a low-grade coal having a particle diameter of 3 mm or less with a petroleum light oil having an average boiling point of 150 to 300 ° C. And heating the slurry mixture to dehydrate the low-grade coal in oil and impregnating the low-grade coal with petroleum light oil so that the low-grade coal is contained therein. Obtaining a modified low-grade coal in which the content of petroleum light oil separated and remaining in the low-grade coal is adjusted to 1 to 10% by mass based on the mass of the anhydrous low-grade coal. This is a method for producing high-grade coal (second invention).

Low-grade coal as described above and average boiling point: 150 to 30
When a slurry mixture containing petroleum light oil at 0 ° C. is heated to dehydrate low-grade coal in oil, water evaporates from the pores of the low-grade coal during this heating, and steam is generated. Thereby, dehydration of low-grade coal is performed. Next, when the slurry-like mixture is cooled, the inside of the pores of the low-grade coal loses vapor pressure in the cooling process, so that a vacuum or a state close to the vacuum is obtained. The interior of the pores is wet with petroleum light oil,
The low-grade coal can be impregnated with petroleum light oil and contained.

In general, coal has a strong aromaticity and shows a crude (phobic) oil property to an aliphatic petroleum light oil, so that it was conventionally difficult to wet the inside of the pores of the coal with the petroleum light oil. However, by performing the above-mentioned dehydration in oil, the inside of the pores of the low-grade coal can be wetted with the petroleum light oil, and the petroleum light oil can be impregnated and contained.

After dehydration in oil, the slurry mixture is subjected to solid-liquid separation. For example, a solid (low-grade coal containing petroleum light oil) is separated from the slurry mixture, and the petroleum light oil is mechanically or thermally recovered from the solid. At this time, the content of the petroleum light oil remaining in the low-grade coal is adjusted to 1 to 10% by mass based on the weight of the anhydrous low-grade coal. Then, the low-grade coal has a particle size of 3 mm or less, and the content of the petroleum light oil remaining in the low-grade coal is 1 to 10% by mass based on the weight of the anhydrous low-grade coal. Is obtained. The mass of anhydrous low-grade coal is the mass of low-grade coal when the low-grade coal is in an anhydrous state.

The modified low-grade coal thus obtained is
The water content is extremely low and the water repellency is excellent. Therefore, if this is used as a raw material coal for CWM, the maximum concentration of low-grade coal in CWM can be increased, and the low-grade coal concentration is high and the calorie content is low. Highly modified low-rank coal CWM can be obtained.

In the present invention, the low-grade coal has a particle size of 3 mm or less as described above for the following reasons.

If the particle size of the low-grade coal is more than 3 mm, it is difficult to impregnate and adhere the petroleum-based light oil to the inside of the pores of the low-grade coal during dehydration in oil. This reduces the water repellency. That is, when the low-grade coal is re-crushed into fine powder during the production of CWM, a portion to which petroleum light oil is not attached is exposed on the surface, and the water repellency is reduced in this portion. As a result, the maximum concentration of coal (low-rank coal) in CWM decreases.

On the other hand, when the particle size of the low-grade coal is 3 mm or less, the petroleum light oil can be impregnated and adhered to the inside of the pores of the low-grade coal. That is, even the inside of the low-grade coal can be modified to be essentially water-repellent. In this case, the water repellency is not lost or reduced by the re-grinding during the production of CWM, and the re-grinding has the same good water repellency as before the pulverization. Can increase the maximum concentration.

If the particle size of the low-grade coal is more than 3 mm,
Pumping and heating operations in a heat exchanger may occur before and after dehydration in oil during the production of modified low-grade coal, whereas when the particle size of low-grade coal is 3 mm or less, such an obstacle may occur. Does not occur.

Next, as an oil for mixing with low-grade coal to form a slurry mixture, that is, an oil for dehydrating low-grade coal in oil and adhering to oil impregnation, petroleum-based light oil having an average boiling point of 150 to 300 ° C. The reason for using oil is as follows.

Oil for dehydration in oil must not evaporate before water during dehydration in oil. That is, it is necessary that the water in the low-grade coal first evaporates, and then the low-grade coal is impregnated with the oil. From this point, it is first necessary that the boiling point is higher than 100 ° C. However, if the boiling point is lower than 150 ° C, there is a problem that a large amount of oil evaporates during dehydration in oil. In addition, after dehydration in oil and oil impregnation, it is necessary to obtain a modified low-grade coal by adjusting the oil content by solid-liquid separation and recover the oil content. It is necessary to recover excess oil from the low-grade coal by heating it to a temperature higher than the boiling point of the oil and drying it by heat. If the boiling point of the oil exceeds 300 ° C., the low-grade coal thermally degrades Therefore, it is necessary that the oil has a boiling point of 300 ° C. or less. Therefore, the oil for dehydration in oil was determined to have an average boiling point of 150 to 300 ° C. The average boiling point is from 150 to 250 ° C. from the viewpoint of making the recovery of oil by thermal drying easier.
It is desirable to use an oil of In this way, the oil is thoroughly recovered except for the part that causes it to impregnate and adhere, but it is expensive compared to coal, and the recoverable oil should be recovered. This is because the total cost related to the coal production process increases, and the significance and value of reforming low-rank coal and increasing the calories of CWM decrease.

The oil for impregnating and adhering to low-grade coal needs to be capable of modifying low-grade coal to be water-repellent, and for this purpose it is necessary to be hydrophobic. Petroleum-based light oils (kerosene, light oil) have excellent hydrophobicity. Therefore, petroleum-based light oil was used. A small amount (for example, 1 to 2%) of heavy oil such as asphalt may be added to petroleum light oil. Although this heavy oil cannot be recovered, it absorbs low-grade coal and contributes to increasing calories and improving water repellency.
It also acts as a surfactant to improve the dispersion of low-grade coal in oil during dehydration in oil.

Next, the content of the petroleum-based light oil remaining in the low-grade coal after the dehydration in oil and the solid-liquid separation after the oil impregnation and adhesion (hereinafter also referred to as the residual oil amount) is changed to the mass of the anhydrous low-grade coal. 1 to 10% by mass with respect to the following reason.

When the residual oil content is less than 1% by mass, the water repellency of the low-grade coal is insufficient, and it is difficult to obtain a CWM with a high maximum concentration of the low-grade coal in CWM. On the other hand, when the residual oil content is 1% by mass or more, a sufficiently modified low-grade coal having excellent water repellency and a high concentration of the low-grade coal in CWM can be obtained. However, oil is extremely expensive as compared with low-grade coal, and if it exceeds 10% by mass, the economical efficiency is deteriorated. From this point, the residual oil amount is 1
To 10% by mass. In order to more reliably obtain a modified low-grade coal having excellent water repellency, the residual oil content is desirably 1.5% by mass or more. On the other hand, from the viewpoint of economy, the residual oil content is 5% by mass or less. It is desirable to do.

The effect of the residual oil amount on the water repellency of such low-grade coal can also be seen from FIG. In other words, FIG. 2 shows the relationship between the residual oil content and the constant humidity moisture for low-grade coal obtained when Australian brown coal, which is a typical example of low-grade coal, is reformed by dehydration in oil.
Shown in This constant moisture is usually measured by the method of JIS M8811. In this method, the sample is allowed to stand in a constant-humidity container containing a saturated saline solution until it reaches a constant weight, and then dried at 107 ° C. ± 2 ° C. to a constant weight, and the constant moisture is determined from the difference in mass. This constant moisture is a measure of the strength of the water repellency. In other words, the stronger the water repellency, the lower the constant humidity moisture, and the weaker the water repellency, the higher the constant moisture. According to FIG. 2, the constant humidity shows a saturation phenomenon when the residual oil amount is 1.5% by mass or more, and even when the residual oil amount is 1% by mass, the saturation level is very close to this saturation level.
From these facts, it is expected that the residual oil content of 1% has a considerable effect on the development of hydrophobicity, and that an almost reliable effect can be expected if the residual oil content is 1.5% or more. In addition, Australian lignite has a large O / C ratio of less than 0.3,
In addition, since it belongs to the low-grade coal having the largest inner surface area, even in low-grade coal other than Australian lignite, it can be said that the water repellency is sufficient if the residual oil amount is 1% by mass or more.

The modified low-grade coal according to the first aspect of the present invention is CWM
When CWM is manufactured using the raw material coal of the present invention, the modified low-grade coal CWM (ie, the CW according to the third invention) in which the maximum concentration of coal (modified low-grade coal) in the CWM is high and the calorie is high.
M) is obtained. The production of CWM is usually carried out by a wet method in which a raw material of modified low-grade coal and water or a surfactant is supplied to a pulverizer such as a ball mill and a surfactant is mixed and pulverized. At this time, the modified low-grade coal of the raw coal (before mixing and pulverization) has a particle size of 3 mm or less, usually on the order of mm, but becomes fine particles of 1 to 500 μm by mixing and pulverization. That is, in this case, the modified low-grade coal in the CWM exists in a state of the modified low-grade coal obtained by being pulverized by mixing and pulverization. On the other hand, when the particle size of the modified low-grade coal of the raw coal is extremely fine, CWM can be produced only by mixing with little pulverization. In this case, the modified low-grade coal in CWM is almost pulverized. Will exist in a state that will not be done.

[0037] Japanese Patent No. 2607424 describes that low-grade coal is coated with oil and dehydrated in oil for reforming. This reforming method is common to the above-described present invention in that it is dehydrated in oil, but the particle size of the low-grade coal applied with oil is 1 /
It is described as 2 to 3 inches, which is extremely coarse as compared with the case of the present invention (particle size: 3 mm or less), and is particularly different in this point.

When the low-grade coal to be dehydrated in oil has a large particle size as in the case of the above-mentioned publication, oil is impregnated and adhered to the inside of the pores of the low-grade coal, and the inside of the low-grade coal is essentially impregnated. Since it is extremely difficult and almost impossible to modify to water repellency, re-grinding during the production of CWM exposes many surfaces to which oil is not attached, and loses or reduces water repellency, As a result, the maximum concentration of low-rank coal in CWM cannot be increased so much. On the other hand, in the case of the present invention, since the particle size of the low-grade coal to be dehydrated in oil is extremely small (3 mm or less), the oil is impregnated and adhered to the inside of the pores of the low-grade coal as described above. In addition, the inside of the low-grade coal can be modified to be essentially water-repellent, so that the water-repellency is not lost or reduced by re-grinding during CWM production. Has a similar good water repellency and thus CWM
Can increase the maximum concentration of low-grade coal. In particular,
In this respect, the operation described in the above publication and the invention are remarkably different.

In addition, the present invention is different from the above-mentioned publication in the constitution, operation and effect in the point of oil for dehydration in oil, amount of oil contained in low-grade coal, type of oil and the like. .

When the high-grade coal having an average particle size larger than the average particle size of the modified low-grade coal in the CWM is present (coexisting) in the CWM of the present invention, the fluidity of the CWM is improved. And therefore the amount of modified low rank coal that can be included in the CWM can be increased, and thus the highest concentration of the modified low rank coal in the CWM and the high calorie CWM (ie, 6th
CWM according to the invention). The details, particularly the details of the improvement in the fluidity, will be described below.

In the case of low-grade coal, particles obtained by pulverizing the same with a pulverizer, particularly particles obtained by pulverizing with a usual pulverizing means such as a ball mill, have a high quality as shown in FIG. Poor sphericity compared to charcoal. When the particles having poor sphericity are mixed with water to form a suspension, that is, CWM, even if the particles are finely packed in the suspension, the suspension (CWM) has a resistance to deformation. Since it is strong, the apparent viscosity is increased, and sometimes the apparent viscosity is increased as the deformation speed is increased.

On the other hand, in the case of a high-rank coal having a high degree of carbonization, such as bituminous coal, even particles obtained by ordinary pulverization, for example, ball mill pulverization, have a high sphericity as exemplified in FIG. 3 (B).

The high-grade coal particles having a high sphericity are present in the modified low-grade coal CWM. At this time, as the high-grade coal particles, those having an average particle size larger than the average particle size of the modified low-grade coal are present. That is, high-grade coal particles having a larger average particle size and higher sphericity than the modified low-grade coal in the CWM are present in the CWM. Then, the resistance to deformation can be reduced and the fluidity can be improved. That is, CW
In M, the high-grade coal particles have a bearing or wheel function in the modified low-grade coal particles, so that the fluidity is improved. Therefore, the amount of the modified low-grade coal that can be contained in CWM can be increased without increasing the viscosity by coexisting the high-grade coal particles. As a result, CWM having a high maximum concentration of the modified low-rank coal in CWM and having high calories can be obtained.

The reason why the average particle size of the high-grade coal particles coexisting with the low-grade coal is larger than that of the low-grade coal is as follows.

As shown in FIG. 4, in a state where a sphere is sandwiched between two plates (plate-like particles), when the size of the sphere is small, the friction reducing effect of the sphere is parallel to each other. When the size of the sphere is large, the effect of reducing the friction of the sphere is not limited to the displacement of such parallel plates. Is big. Here, low-grade coal particles having poor sphericity can be regarded as plate-like particles or similar ones, and high-grade coal particles having high sphericity can be regarded as spheres or similar ones. Then, when low-grade coal particles having poor sphericity and high-grade coal particles having high sphericity coexist, when the high-grade coal particles are large, the degree of freedom in the direction of the friction reducing effect is large.

As described above, when the degree of freedom in the direction of the friction reducing effect of the high-grade coal particles is large, the resistance to deformation of the CWM is weak, and the fluidity thereof is improved. That is, the modified low-grade coal particles have poor sphericity and are paper-like or thread-like. Since such modified low-grade coal particles exist in the three-dimensional liquid space of CWM in water, the directionality of each particle is different. On the other hand, since the deformation of the CWM has directionality, if the degree of freedom of the direction of the friction reducing effect of the high-grade coal particles is large, the resistance to the deformation of the CWM is weak and the fluidity is improved.

Therefore, the average particle size of the high-grade coal particles coexisting with the low-grade coal is made larger than that of the low-grade coal.

It is desirable that the high-grade coal particles in the CWM have a high sphericity. For this purpose, it is necessary that the high-grade coal in the raw material state be one that becomes particles with high sphericity when pulverized. The high-grade coal particles are C
It is necessary that the burning rate during WM burning is not too slow. From this viewpoint, high-grade coal that satisfies these points is
The O / C ratio is in the range of 0.03 to 0.15.

As described above, the average particle size of the high-grade coal particles coexisting with the low-grade coal is larger than that of the low-grade coal.
It is desirable to take into consideration the practicality and the like, as described below, in terms of the specific average particle size. That is, the particle size of coal in CWM is usually 1 to 500.
μm is considered to be good, and coal coarse particles exceeding 1000 μm are undesirable because of sedimentation.
It is not practical in terms of energy and equipment to produce a large amount of coal particles significantly lower than the above, and is not practical. The particles obtained by pulverization have a certain particle size distribution.
In consideration of such circumstances, the particle size distribution on the low-rank coal side is 1 to
500 μm, and the particle size distribution on the high-grade coal side is 10-1000 μm,
Desirably, the thickness is 50 to 1000 μm. In this case, the effect of improving the fluidity of the CWM can be obtained, and the CWM having the highest concentration of coal in the CWM and having a high calorie can be obtained. However, the average particle size of the low-rank coal and the average grain of the high-rank coal particles are obtained. When the difference from the diameter is small, the effect of improving the fluidity of the CWM is small, so that the difference in the average particle diameter is preferably large.

CWM when the present invention is actually applied
FIG. 5 shows an example of the manufacturing process. In the process illustrated in FIG. 5, once the modified low-rank coal CWM is manufactured,
This is transported to a remote place by sea or pipeline transportation, where the high quality coal particles obtained by coarsely pulverizing the high quality coal with respect to the modified low quality coal CWM (the average particle size is higher than that of the modified low quality coal in the CWM) (Large diameter) is mixed to obtain CWM. In mixing the high-grade coal particles, it is necessary to prevent the average particle size of the high-grade coal particles from being smaller than the average particle size of the modified low-grade coal, and for that purpose, it is easily crushed as high-grade coal When bituminous coal or the like is added, it is preferred that the mixture is not mixed and pulverized, but only mixed.
If high-grade coal, such as bituminous coal, which is difficult to pulverize, is added, it may be mixed and pulverized. The high-grade coal particles may be mixed at the production site of the modified low-grade coal CWM.

As described above, the modified low-rank coal CWM
When high-grade coal having an average particle size larger than the average particle size of the modified low-grade coal in the coexistence, the fluidity of CWM can be improved, and therefore, the amount of the modified low-grade coal that can be contained in CWM Therefore, CWM having high maximum concentration of modified low-rank coal in CWM and high calories (CWM according to the sixth invention) can be obtained. This effect is obtained not only when the modified low-grade coal of the base (mainly coal) coexisting with the high-grade coal is the modified low-grade coal according to the first invention, but also in the case other than the reforming means by the in-oil dehydration method. In the case of the modified low-grade coal obtained by the above-mentioned reforming means, the same can be obtained.

Further, even when the main coal is not low-grade coal but low-grade coal (low-grade coal that has not been reformed), the same effect as described above can be obtained. That is,
When high-grade coal having an average particle size larger than the average particle size of the low-grade coal in the CWM is allowed to coexist with the low-grade coal CWM, the fluidity of the CWM can be improved, and therefore, the low-grade coal that can be contained in the CWM is reduced. It is possible to increase the amount of charcoal, and thus to obtain a CWM having a high concentration of low-grade coal in the CWM and a high calorie (the CWM according to the fourth invention).

The CWM is obtained by once obtaining a low-grade coal CWM and then mixing the CWM with a high-grade coal having an average particle size larger than that of the CWM medium-low-grade coal, thereby obtaining the low-grade coal and the low-grade coal. It is possible to obtain a CWM (CWM according to the fifth invention) in which high-grade coal having an average particle size larger than that of the high-grade coal coexists.

As described above, in the CWM including the low-grade coal and the high-grade coal having an average particle size larger than that of the low-grade coal (the CWM according to the fourth, fifth, and sixth inventions), Coal) is a low-rank coal, so the amount of high-rank coal is less than the amount of low-rank coal. The amount of high-grade coal at this time is not particularly limited, but is preferably 10 to 30% by mass based on the amount of coal (total amount of low-grade coal and high-grade coal). That is, when the amount of high-grade coal is less than 10% by mass, the degree of improvement of CWM fluidity by high-grade coal is low,
The meaning of calorie up is diluted, so 10% by mass
Although it is desirable to increase the amount as described above, if it exceeds 30% by mass, the amount of high-grade coal is too large, which causes a decrease in economic efficiency.

Incidentally, Japanese Patent Publication No. 7-84670 discloses a CWM containing low-grade coal and high-grade coal. But,
The low-grade coal is coarse and the high-grade coal is fine powder. The high-grade coal has a finer grain size than the low-grade coal. This is intended to reduce the surface area of low-grade coal that consumes a large amount of surfactant, thereby reducing the amount of surfactant used. Therefore, it is apparent that the object described in this publication differs from the present invention (the fourth to seventh inventions) in the purpose and configuration in the above-described points, and also in the operation and effect. In other respects as well, the two have different configurations and operational effects.

When CWM is used as a fuel, the calorie of CWM is an important matter, and it is desired that the calorie be high. In addition, the basicity and melting point of coal ash (coal ash) of CWM are also important. The basicity and melting point of coal ash are adjusted depending on the use of CWM.
The current situation and problems in this regard, and the countermeasures are described below.

In a general coal boiler (hereinafter also referred to as a pulverized coal-fired boiler), it is preferable that the melting point of coal ash be high in order to avoid slagging (furnace fouling) or to obtain a large heat flux. . Therefore, coal importing countries have purchased high-melting ash (high-melting ash) coal, and low-melting ash coal is being used in coal-producing areas in inefficient boiler furnaces designed to reduce heat flux. On the other hand, in the case of a slag tap type (wet bottom type) spouted bed gasifier which is becoming the mainstream of a power gasifier, it is preferable that the melting point of coal ash be low. Therefore, a so-called flux mainly composed of Ca is added to high-grade coal to raise the basicity of coal ash and lower the melting point.

When low-grade coal CWM is used in such a boiler or furnace, there are the following problems. Since low-grade coal has a high water content, it has an ion-exchange mineral (N
a, Ca, K, Mg, etc.) and ash (coal ash)
Has a high basicity. Such an ash having a high basicity tends to have a low melting point of the ash, and there is a concern that a general coal boiler may cause in-furnace contamination such as slagging. Further, when the basicity is too high, the melting point tends to increase, and such low-grade coal is difficult to use in a slag tap type spouted bed gasifier.

Low-grade coal is highly reactive and has favorable basic physical properties for furnaces and gasifiers. However, if the melting point of the ash cannot be adjusted, the problems described above make it difficult to use. There is. Therefore, it is important to be able to adjust the melting point of the ash. Notably, low-rank coals having an ash content of not more than 5% by mass (based on dry coal) based on the weight of anhydrous low-rank coal are not limited to Australia and Indonesia.

In contrast to the case of the low-rank coal, the ash of the high-rank coal has a large amount of SiO ₂ and Al ₂ O _{3 and a} low basicity. In addition, the ash content is hardly extremely small, and there are few cases where the dry coal ratio is 10% by mass or less even when the coal is cleaned.

The basicity as described above is calculated based on the ratio Base / Acid = [Ca
_{O + Fe 2 O 3 + MgO} + Na 2 O + K 2 O ] / _{[SiO 2 + Al 2 O 3 +} TiO 2 ] is often evaluated (hereinafter, the ratio of B / A ratio). It is generally known that as the B / A ratio increases, the melting point decreases. When purchasing coal for boilers, it is often the case that an upper limit is set for the B / A ratio and an index containing the same. In addition, in the gasification furnace and the blast furnace for steelmaking, a technique has been already established in which a flux containing Ca is added and mixed to increase the B / A ratio and lower the melting point.

It is known that if the basicity (B / A ratio) is higher and too high, the melting point will be higher.
This can be seen from, for example, Table 3 and FIG. This Table 3
FIG. 11 shows the relationship between the B / A ratio and the melting point. Although there is some width (error), FIG. 11 and Table 3 are typical data in the sense that many coal ash data follow the diagram showing the relationship between B / A ratio and melting point shown in these charts. .

In FIG. 11, coal having a B / A ratio of 1.0 or more is hereinafter referred to as ultrabasic ash coal. Ultra-basic ash coal is almost low-grade coal, and its melting point is already high due to basic components.
Alternatively, the melting point can be increased by adding a flux as described above. However, in the case of such an ultrabasic ash coal, even if slagging in a coal boiler furnace can be prevented, so-called fouling in which the base component adheres to the heat transfer tube in the convection heat transfer section becomes severe, and the use cannot be tolerated. Such ultra-basic ash charcoal should be able to be used in the above-described spouted bed gasifier if its basicity is lowered to lower its melting point.

In the CWM in which the above-mentioned low-grade coal (or modified low-grade coal) and high-grade coal having an average particle size larger than that of the low-grade coal coexist, the content of the high-grade coal is The ash content of low-rank coal is small (5 mass% or less), while the ash content of high-rank coal is high (10 mass% or more), but the B / A ratio of this high-rank coal is sufficiently small ( For example 0.2
In this case, as shown in Table 4 and FIG. 12, by adding such high-grade coal, the B / A ratio of the ash of CWM can be reduced and the melting point can be greatly reduced, making it suitable for gasification furnace applications. CWM.

When the B / A ratio of the low-rank coal is around 0.5 and the melting point is near the minimum value, when a high-rank coal having a low B / A ratio coexists, as shown in Table 5 and FIG. , The B / A ratio can be lowered by lowering the relative concentration of the basic component of the ash content of CWM, and the melting point of the ash content of CWM can be raised accordingly. Such CWM is suitable for use in coal boilers because slagging and fouling hardly occur due to a small ash B / A ratio and a high melting point.

By coexisting the high-grade coal with the modified low-grade coal in this way, the basicity and melting point of the ash of CWM can be accurately adjusted. The same is true for the case where low-grade coal is used in place of the above-mentioned modified low-grade coal. By coexisting high-grade coal with low-grade coal, the basicity and melting point of the ash content of CWM can be accurately adjusted. can do. That is, the basicity of ash is high (normally, B / A ratio: 0.5 or more),
Low-grade coal with low ash content (usually dry coal mass ratio: 5% or less) has low ash basicity (usually B / A ratio: 0.2 or less)
By coexisting high-grade coal having a large amount of ash (usually dry coal mass ratio: 10% or more), the basicity and melting point of the ash in CWM can be accurately adjusted. For example, B / A as low-grade coal
When low-grade coal having a ratio of around 0.5 is used, coexistence of high-grade coal can lower the basicity of ash in CWM and increase the melting point, resulting in CWM in which slagging and fouling are unlikely to occur. In addition, when the B / A ratio of low-grade coal is relatively high and the melting point is high, the co-presence of high-grade coal can lower the basicity of ash in CWM and lower the melting point. It becomes a suitable CWM.

[0067]

[Example A] The CWM according to the example of the present invention and the CWM according to the comparative example have a high concentration property,
The degree of maximum concentration of coal in the WM was determined, and the calorie was also determined. The details will be described below.

Since the maximum concentration of coal in the CWM varies within a certain range according to the viscosity of the CWM, it is necessary to compare the viscosity in order to evaluate the high concentration. In measuring this viscosity, it is common to measure the viscosity of a suspension such as CWM with a rotating cylinder viscometer, but since CWM is not a Newtonian fluid and the apparent viscosity varies with time and shear rate, It is necessary to establish a standard for measuring viscosity. Therefore, after increasing the shear rate for CWM, it is held for a certain period of time, and then, the shear rate is reduced to a certain value, for example, the apparent viscosity at the time when the shear rate reaches 100 / sec. In many cases, a method is used in which the concentration of coal at the time of is set as the maximum concentration of coal in the CWM, and the high concentration property is compared between the coals.

Therefore, as described above, the coal concentration when the apparent viscosity becomes 1000 cp when the shear rate becomes 100 / sec (the coal concentration that becomes 1000 cp at 100 / sec-down) is the maximum concentration of coal in the CWM. Was measured. That is, CWMs of various coal concentrations were prepared, and the apparent viscosities of these were measured at a shear rate of 100 / sec as described above, and a CWM having an apparent viscosity of 1000 cp was examined.
The coal concentration at M was taken as the highest concentration of coal at CWM. Further, for the CWM having the highest concentration, the calorie per unit mass of the CWM was obtained by calculation using calorie data of coal and the like.

The following CWM was measured:
belongs to.

Low-grade coal CWM ---- Lignite (Royan coal, Australia), which is a low-grade coal, is pulverized to under 3 mm and mixed with water and an anionic additive (PSS: Sodium Polystylene).
Su-lfonate) and wet-mixed and pulverized for 15 minutes with a 10 L ball mill to form CWM. The amount of the above additive is 0.5% by dry coal mass ratio. The ratio between the amount of lignite and the amount of water was varied in order to examine the maximum concentration of coal in CWM.

Dry low-grade coal CWM ---- Lignite (raw lignite) similar to the above is dried at 107 ± 2 ° C. to a constant weight, and then pulverized lignite, water and additives are added and mixed as described above. What was made into CWM by pulverization.

Modified low-grade coal CWM --- Modified low-grade coal produced according to the following procedure, pulverized, water and additives added, mixed and pulverized into CWM by the same method as described above. Production procedure of modified low-grade coal ---- 3 lignite similar to above
The slurry pulverized to a size under mm was mixed with kerosene (average boiling point: about 200 ° C.) as a petroleum light oil to obtain a slurry. At this time, the mixing ratio of kerosene to brown coal 1 was 2.3 in terms of dry coal mass ratio.
It is. Next, the slurry is heated indirectly with steam to produce
After dehydrating the lignite in oil at 140 ° C. and 3 kg / cm ² G and impregnating and adhering the kerosene to the lignite, the slurry was solid-liquid separated by a centrifuge to remove the lignite to which the kerosene was impregnated. Separated from kerosene. Next, this lignite is placed in an oven for 150
The dried oil was heated to ° C. and the excess oil was evaporated to obtain a modified low-grade coal in which the content of the oil remaining in the lignite was adjusted to 2% by dry coal mass ratio.

Modified low-grade coal CWM to which coarse-grained high-grade coal is added ---- The above-mentioned modified low-grade coal CWM has an average grain size smaller than the average particle size of the low-grade coal in the CWM. A mixture of high-quality coarse coal (Mount Soli coal, Australia) with a large diameter. At this time, the amount of high-grade coal added was 1/7 of the amount of modified low-grade coal. Therefore, the ratio of high-grade coal to coal (modified low-grade coal and high-grade coal) in CWM is 12.5% by mass. The particle size distribution of the modified low-grade coal is 1 to 300 μm, and the average is 15 μm. The particle size distribution of high-grade coal is 70-500 μm.

Low-grade coal CWM to which coarse-grained high-grade coal has been added ----
A mixture obtained by adding and mixing coarse-grained high-grade coal (Mountsori coal) whose average particle size is larger than the average particle size of low-grade coal in WM. At this time, the amount of high-grade coal added is 1 / the amount of low-grade coal.
The amount was 7. Therefore, the ratio of high-rank coal to coal (low-rank coal and high-rank coal) in CWM is 12.5% by mass.
The low-grade coal has a particle size distribution of 1 to 300 μm and an average of 15 μm. Particle size distribution of high-grade coal is 70-500 μm
It is.

High-grade coal CWM ---- High-grade coal (Mount Soli coal, Australia) is ground by the same method as above.
CWM made by adding water and additives, mixing and grinding.

The maximum concentration of coal in the above CWM (100 / sec-
Table 1 shows the measurement results of the coal concentration that is 1000 cp at the time of Down), and the calorie calculation results for the CWM having the highest concentration.

As can be seen from Table 1, low-rank coal CWM
In this case, the maximum concentration of coal in the CWM is only 24%.
The calorie is about 1500kcal / kg and cannot burn itself, so it cannot be used as fuel.

In the case of the dry low-rank coal CWM, the maximum concentration of coal in the CWM is 35%, and the low-rank coal CW
It is higher than M. This is because the physical shape of coal changes irreversibly due to dehydration by drying, and pores are lost. However, since the hydrophilicity remains, the maximum concentration of coal in CWM is not sufficient.

In the case of the modified low rank coal CWM, the maximum concentration of coal in the CWM is 48%, and the low rank coal CW
Significantly higher than M. This is because the modified low-grade coal had excellent water repellency due to the modification. This water repellency is obtained by a small amount of oil uniformly adsorbed on the internal pores by reforming during dehydration in oil, and is not due to a chemical change. I understand well. That is, Table 2 shows the chemical composition of low-grade coal before and after reforming in oil. As can be seen from this, although there is a slight change due to the adsorption of trace oil,
Since there is no significant change in the chemical composition before and after the reforming, no chemical change has occurred during dehydration in oil. In addition, slightly O / C
The ratio has decreased, which is due to a slight loss of the functional groups of the modified low-grade coal during the oil recovery by heating at 150 ° C. Strictly speaking, the reduction of the O / C ratio may increase the maximum concentration of coal in the CWM, but the degree is extremely small, and the effect of the water repellency is much greater. This is clear from FIG.

In the case of CWM obtained by adding coarse-grained high-grade coal to the modified low-grade coal CWM, the maximum concentration of coal in the CWM is 55%, which is higher than that of the above-mentioned modified low-grade coal CWM. Will also be higher. Although this increase is 7%, it is desirable that the maximum concentration of coal in the CWM is as high as 1% from the viewpoint of calorific value and economy, and from that point, it can be said that the increase of 7% is extremely large. .

In the case of the high-rank coal CWM, the maximum concentration of coal in the CWM is 68%.

Regarding the effect of adding coarse-grained high-grade coal to the above-mentioned modified low-grade coal CWM, this is the effect of simply setting the ratio between the modified low-grade coal and high-grade coal to simply 48: 7. Then, the maximum concentration of coal (low-grade coal) in CWM is 50%
Although the degree is a reasonable value, the highest concentration (48%) in the case of the above-mentioned modified low-grade coal CWM can be obtained only by coexisting the high-grade coal in an amount of only 1/7 of the modified low-grade coal. The highest concentration (55%), which is almost the median of the highest concentration (68%) in the case of high-grade coal CWM, is due to the rheological improvement that the above-mentioned coarse-grained spherical high-grade coal improves fluidity. This is due to the effect.

This can be explained from a rheological curve. The details will be described below.

FIG. 6 shows a rheological curve for the high-rank coal CWM. When the CWM is allowed to stand, the apparent viscosity is high to maintain a pseudo structure due to weak interaction between the particles, but as the shear rate increases, the higher the shear rate, the longer the time,
The binding force is weakened, and the apparent viscosity is reduced. This is called thixotropic. The rheological curve in FIG. 6 substantially qualitatively follows a theory presuming spherical particles if not strictly.

On the other hand, FIG. 7 shows data on the modified low-rank coal CWM. As the shear rate increases, the apparent viscosity increases. This shows a so-called dilatancy. This is because the modified low-rank coal has a non-spherical particle shape, and thus has a strong resistance to deformation. Irreversible changes due to dehydration are also considered to be a factor. For this reason, the maximum concentration of the modified low-rank coal CWM cannot be higher than that of the high-rank coal.

When coarse spherical high-grade coal is added to the modified low-grade coal CWM in an amount 1/7 that of the modified low-grade coal, the CW
The rheological curve of M is as shown in FIG. 8, and the dilatancy disappears and the same rheological characteristics as in the case of high-grade coal CWM are shown. The rheology is completely changed by the addition of the overwhelmingly small amount of high-grade coal. Here, there is the origin of the idea of the present invention that low-grade coal coexists with coarse-grained high-grade coal particles, and the effect is not merely added by the addition of coarse-grained high-grade coal particles.
A synergistic effect is produced and a remarkable effect is achieved.

In the case of CWM obtained by adding coarse-grained high-grade coal to low-grade coal CWM, the maximum concentration of coal in CWM is as follows:
30.7%, which is higher than that of the low-rank coal CWM described above. Thus, the addition target of coarse-grain high-grade coal is low-grade coal CW
Even in the case of M, the addition of coarse-grained high-grade coal allows CWM
30.7%, the highest concentration of coal in the country increased from 24% to about 7%
become. This maximum concentration is lower than in the case of the modified low-rank coal CWM, because the maximum concentration of the low-rank coal CWM is originally lower, and the lower-rank coal is of higher quality and lower-rank coal. If the highest concentration of coal (low-rank coal) in CWM is higher and more than 24%, coarse-grained high-rank coal is added to the low-rank coal CWM as the highest concentration of low-rank coal increases. The resulting CWM has a higher maximum coal concentration. Thus, the higher the quality of the low-rank coal, the higher the concentration of the CWM coal is, while the higher the quality of the low-rank coal, the higher the quality of the coal. The degree (improvement ratio) is reduced, and the degree of improvement of the maximum concentration of coal in CWM by using modified low-grade coal by dehydration in oil tends to be small. The effect of the addition of coarse-grained high-grade coal (the effect of improving the maximum concentration of coal in CWM) becomes remarkable, and its significance is deeper and the role it plays becomes greater.

[Example B] In the case where the modified low-grade coal CWM was added with coarse-grained high-grade coal (), the particle size distribution of the high-grade coal was 70 to 500 µm. Used high-grade coals with different particle size distributions. Except for this point, CWM was obtained in the same manner as described above.
And the viscosity of this CWM was measured. The result is shown in FIG.
(A) and (B) of FIG. FIG. 9 (A) shows the result when the amount of high-grade coal added: 20%, and FIG. 9 (B) shows the result when the amount of high-grade coal added: 30%. In either case,
It can be seen that the viscosity of CWM is lower when the particle size of the high-rank coal added to the modified low-rank coal CWM is large.

[Example C] In the case of (C) in which the coarse-grained high-grade coal was added to the modified low-grade coal CWM, the amount of the high-grade coal was 7% by mass with respect to the amount of the modified low-grade coal. However, in Example C, the amount of high-grade coal added was changed. or,
Mixing and pulverization at the time of CWM conversion was performed using a high-speed stirring type equipment instead of a ball mill. Except for this point, CWM was obtained in the same manner as described above. And CWM
Was measured when the viscosity reached 1000 cp (the highest concentration of coal in CWM). The result is shown in FIG.
In FIG. 10, (B) is based on the assumption that a simple coal-mixing was performed without any device for particle size adjustment as in the present invention, that is,
The highest concentration when no high-rank coal is simply added to low-rank coal and there is no rheological effect, (A) is when the coal is mixed while performing rheological improvement according to the present invention,
That is, it indicates the highest attainable concentration when the high-quality coarse coal is added to the modified low-grade coal CWM and there is a rheological effect. Since the mixing and grinding at the time of CWM conversion was performed using high-speed stirring type equipment, the maximum concentration of coal in CWM was 51.7%, slightly higher than in Table 1, but a small amount of high-grade coal was added. It can be confirmed that the maximum concentration can be increased and the high concentration property can be improved. High-grade coal added: 30
In the range of 40% to 40%, the higher the amount of high-grade coal added, the greater the effect of increasing the highest concentration. However, considering the price, economy, and effect of addition of high-grade coal, the amount of high-grade coal added [ =
The amount of high-grade coal / (the amount of low-grade coal + the amount of high-grade coal)] is preferably 10 to 30% by mass.

[0091]

[Table 1]

[0092]

[Table 2]

[0093]

[Table 3]

[0094]

[Table 4]

[0095]

[Table 5]

[0096]

The modified low-grade coal according to the present invention has an extremely low water content and excellent water repellency. Therefore, if this is used as a raw material coal for CWM, it is the highest of low-grade coal in CWM. The concentration can be increased, and a low-rank coal having high low-rank coal concentration and high calorie can be obtained.

According to the method for producing a modified low-rank coal according to the present invention, as described above, a low-rank coal having a high concentration of the low-rank coal in the CWM and a high calorie can be obtained.

The modified low-grade coal CWM (CWM using modified low-grade coal as raw material coal) according to the present invention is CWM.
The highest concentration of modified low-rank coal in the country is high and the calories are high, so fuel economy (calories / cost) is excellent,
In addition, since the modified low-grade coal is used as the raw coal, the use of the low-grade coal is expanded.

Coarse grains in the modified low-grade coal according to the present invention (the average particle size is larger than that of the modified low-grade coal in the CWM)
CWM made of high-quality coal of high quality
It has better fluidity than WM and, consequently, has a higher maximum concentration of modified low rank coal in CWM and higher calories.

The low-rank coal CWM according to the present invention, in which coarse-particle high-rank coal is present, has a higher fluidity than the low-rank coal CWM, and as a result, the maximum concentration of the low-rank coal in the CWM is lower. High and high in calories. As described above, the coexistence of coarse-grained high-grade coal with low-grade coal can improve the fluidity of CWM and increase the maximum concentration of low-grade coal in CWM. Practicality can be improved, and in particular, low-grade coal which could not be converted to CWM can be converted to CWM, and the use of such low-grade coal as a CWM raw material can be expanded.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the O / C ratio of coal and the maximum concentration of coal in CWM.

FIG. 2 is a diagram showing the relationship between the residual oil amount and the constant moisture for modified low-grade coal.

FIG. 3 is a drawing substitute photograph showing a micrograph of coal particles, in which (A) of FIG. 3 shows low-grade coal particles obtained by pulverizing low-grade coal with a pulverizer; B) is for high-grade coal particles obtained by grinding high-grade coal with a crusher.

FIG. 4 is a diagram illustrating the relationship between the fluidity of low-grade coal CWM, the fluidity of CWM obtained by adding high-grade coal particles to low-grade coal CWM, and the particle size of high-grade coal particles. 4 (A)
FIG. 4 is an explanatory view of low-rank coal CWM, and FIG.
Fig. 4 is an explanatory view of a case where the particle size of the high-grade coal particles that are present is larger than that of the low-grade coal, and Fig. 4C illustrates the case where the particle size of the high-grade coal particles that are present is smaller than that of the low-grade coal. It is explanatory drawing about a case.

FIG. 5 is a diagram illustrating an example of a CWM manufacturing process according to the present invention.

FIG. 6 is a diagram showing a rheological curve (ie, a change in apparent viscosity with a change in shear rate) for a high-rank coal CWM.

FIG. 7 is a diagram showing a rheological curve (ie, a change in apparent viscosity with a change in shear rate) for a modified low-rank coal CWM.

FIG. 8: Rheological curves for CWM obtained by adding coarse spherical high-grade coal to modified low-grade coal CWM in an amount 1/7 that of modified low-grade coal (ie, apparent with change in shear rate) FIG.

FIG. 9: C obtained by adding high-grade coal to modified low-grade coal CWM
FIG. 9A is a diagram showing the relationship between the particle size and the viscosity of high-grade coal in WM, where FIG. 9A shows the case where the amount of high-grade coal added is 20%, and FIG. The amount of charcoal added is for the case of 30%.

FIG. 10 is a graph showing the relationship between the amount of high-grade coal added to CWM obtained by adding coarse-grained high-grade coal to modified low-grade coal CWM, and the ultimate coal concentration in CWM.

FIG. 11 Base / Acid ratio (basicity) of coal ash of CWM
FIG. 4 is a diagram showing the relationship between the ash and the softening point of the ash in a reducing atmosphere.

FIG. 12 Base / Acid ratio (basicity) of CWM coal ash
FIG. 3 is a diagram showing the relationship between the ash softening point in a reducing atmosphere and the ash softening point, in particular, adjusting the Base / Acid ratio and the ash softening point of coal ash of CWM by adding high-grade coal to low-grade coal CWM. It is a figure explaining what can be done.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuya Exit 1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture Inside Kobe Research Institute, Kobe Steel Ltd. (72) Inventor Yasuo Wada Amagasaki City University, Hyogo Prefecture 2-23 Hamacho F-term in KN Lab Analysis Co., Ltd. (reference) 4H013 DA02 4H015 AA09 AA11 AB01 AB09 BA09 BB03 CB01

Claims (7)

[Claims] 1. Low-grade coal and average boiling point: 150 to 300 ° C.
And heating the slurry mixture containing petroleum light oil to dewater the low-grade coal in oil and impregnating and adhering the low-grade coal with petroleum light oil to contain the slurry mixture. A modified low-grade coal obtained by adjusting the content of petroleum light oil remaining in the low-grade coal after solid-liquid separation,
The low-grade coal has a particle size of 3 mm or less, and the content of petroleum-based light oil remaining in the low-grade coal is 1 to 10% by mass based on the weight of the anhydrous low-grade coal. Modified low-grade coal. 2. A low-grade coal having a particle size of 3 mm or less is mixed with a petroleum light oil having an average boiling point of 150 to 300 ° C. to obtain a slurry-like mixture. After the coal is dehydrated in oil and the low-grade coal is impregnated with petroleum-based light oil to be contained therein, the slurry-like mixture is subjected to solid-liquid separation, and the petroleum-based light oil remaining in the low-grade coal is removed. Is 1 to 10 with respect to the weight of anhydrous low-grade coal.
A method for producing a modified low-grade coal, wherein a modified low-grade coal adjusted to mass% is obtained. 3. A coal-water slurry containing coal and water, wherein the coal is the modified low-grade coal according to claim 1 or the modified low-grade coal obtained by pulverizing the modified low-grade coal. A coal-water slurry, characterized in that: 4. A coal-water slurry containing low-grade coal and high-grade coal as coal, wherein the average particle size of the high-grade coal particles is larger than the average particle size of the low-grade coal particles. Characterized coal-water slurry. 5. A coal-water slurry obtained by mixing a high-grade coal with a coal-water slurry containing low-grade coal as the coal, wherein the high-grade coal particles have an average particle size of the low-grade coal particles. Coal-water slurry characterized by having an average particle size larger than the above. 6. The coal-water slurry according to claim 4, wherein the low-grade coal is the modified low-grade coal according to claim 1 or the modified low-grade coal obtained by pulverizing the modified low-grade coal. . 7. The amount of high-grade coal in the coal is 10 to 30.
The coal-water slurry according to claim 4, 5 or 6, which is a mass%.