JPH09151385A - Kneader for producing fuel for pressurized fluidized bed boiler, operation of the kneader, pressurized fluized bed boiler and operation of the boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the production of CWP(coal water pastes) keeping enough fluidity with a smaller amount of water and attain high plant efficiency by controlling the kneading of a mixture of crushed coal and water or a mixture of crushed coal, water and a devulcanizing agent in a manufacturing process of CWP and to keep high plant efficiency. SOLUTION: When crushed coal and water (and a devulcanizing agent) are kneaded to produce CWP, a kneader is operated under the condition that the increase in a ratio of an accumulated weight of particles having particle diameters of <=0.02mm through the kneading is in the range of 1-5wt.% based on the particles constituting CWP. Thus, the production of CWP keeping fluidity with a small amount of water is enabled. Kneading energy consumption per CWP weight is determined from the consumed energy in a kneader 6 and the production of CWP by a computer 40. The number of revolution of a rotor and/or a divergence of a gate valve 15 of the outlet of the kneader is controlled so that the value determined by the computer 40 becomes 1-5kWh/ton-fuel, and this condition imparts CWP with an adequate degree of fluidity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coal / water mixed fuel production facility in a pressurized fluidized bed boiler combined cycle power plant, and a method for producing a low moisture coal / water mixed fuel,
The present invention relates to a kneading machine for crushed coal and water or a crushed coal and water and desulfurizing agent suitable for maintaining high plant efficiency, its operating method, a pressurized fluidized bed boiler and its operating method.

[0002]

2. Description of the Related Art In a pressurized fluidized bed boiler combined cycle power plant, a wet supply system is mainly adopted as a method for supplying coal to a furnace. For example, as disclosed in Japanese Patent Laid-Open No. 62-155433, water and a desulfurizing agent are added to crushed coal and mixed by a kneader to form a paste-like fluid (hereinafter, referred to as Coal-Water Pastes; CWP). Abbreviated), and then using a pump to supply the fluidized-bed boiler in a pressurized state. Therefore, regarding the properties of CWP, it is important that the fluidity is such that pumping is possible first, and that the water content in CWP is small in order to maintain high plant efficiency.

The main factors that affect the properties of CWP are the amount of added water, particle size distribution, kneading degree and coal properties. Japanese Patent Application Laid-Open Nos. 62-155433 and 4-57890 disclose CWP production methods having a function of adjusting the amount of added water. Further, JP-A-6-108069 discloses a CWP manufacturing method proposed by the present inventors by adjusting the particle size distribution. CWP fluidized with less water has a weight average particle diameter of 1 to 2 mm. Known literature (S. J. Wright
tet al. : Proceedings of 10
th International Conferenc
e on FBC, p381-388, San Fra
Ncisco, 1989), which has a much coarser grain size composition compared to the CWP having a weight average diameter of 0.1 to 0.5 mm. In order to produce a CWP having a lower water content, it is necessary to adjust the particle size distribution so that the weight average diameter satisfies the range of 1 to 2 mm.

Further, Japanese Patent Application Laid-Open No. 6-108070 discloses a CWP manufacturing method corresponding to different coal properties.

[0005]

SUMMARY OF THE INVENTION In the above-mentioned conventional technique, in order to obtain a fluid CWP with a smaller amount of water, C
No consideration was given to controlling the kneading degree during WP production. Even if the amount of added water and the particle size distribution are adjusted as desired, a CWP having low water content and fluidity cannot be produced unless the degree of kneading is appropriate. That is,
When the kneading is insufficient, the coal particles and the water are in a non-homogeneous state in the manufactured CWP, and a portion having extremely poor fluidity and a portion having a large amount of water and easily separated are formed. Further, when kneading is performed more than necessary, the particles in the CWP, which are characterized by containing relatively coarse particles, are crushed, and the weight average diameter of the constituent particles becomes fine, resulting in no fluidity. As a result, it was necessary to increase the water content in order to be able to transport it with a pump.

Further, in the load changing operation of the boiler, the CWP is manufactured according to the fuel consumption amount at each load. That is, the amount of raw materials such as crushed coal and water supplied to the kneader changes depending on the load. In this case, even if the blending ratio of the raw materials was set, the average kneading time in the kneader varied, so that the degree of kneading described above could not be maintained constant. For example, when the load is reduced, there is a problem that the viscosity of the manufactured CWP is increased by kneading more than necessary in the kneader.

An object of the present invention is to control the kneading degree of crushed coal and water or crushed carbon and water and a desulfurizing agent at the time of CWP production, to produce CWP so as to have fluidity with a smaller amount of water, and To maintain plant efficiency.

[0008]

As a result of intensive studies on the kneading method at the time of CWP production, the present inventors have found that the above-mentioned object of the present invention is to knead crushed coal and water or crushed carbon and water and a desulfurizing agent. When making the CWP, the kneading machine is used so that the increment of the cumulative weight ratio of particles having a particle size of 0.02 mm or less among the particles forming the CWP is in the range of 1 to 5% by weight before and after the kneading. We have found that this can be achieved by driving.

Further, the above-mentioned object of the present invention is, in an apparatus for producing CWP, a means for measuring the power consumption in a kneading machine, and a kneading energy (kWh / kWh) per CWP amount obtained from the measured value and the production amount of CWP. Ton-fuel), and based on the calculated value, a kneading device having a control means for adjusting at least one of the rotation speed of the kneading machine and the opening degree of the kneading machine outlet gate valve is achieved. In this case, the kneading energy obtained by calculation is 1 to 5 (k
Wh / ton-fuel) is desirable.

Instead of the means for controlling the kneader by measuring the power consumption in the kneader, the fluidity of the CWP to be manufactured is measured, and the deviation between the measured value and the set value is calculated and controlled. Means, or, even by a kneading device provided with a means for receiving a boiler load change command and calculating the kneading energy based on the load change signal to control the kneader, the above-mentioned object of the present invention can be achieved. it can.

Further, based on the boiler load change command, the fuel supply amount for supplying the coal-water mixed fuel obtained by kneading to the pressurized fluidized bed boiler is controlled, and the fuel is constituted based on the fuel supply amount. The pressurized fluidized bed boiler may be operated so that the increment of the cumulative weight ratio of particles having a particle size of 0.02 mm or less in the particles is in the range of 1 to 5% by weight before and after kneading.

The present invention includes a method for producing a fuel for a pressurized fluidized bed boiler, a kneader, an operating method thereof, and a pressurized fluidized bed boiler and an operating method thereof as described above.

The present invention focuses on not crushing coal particles, which make up a large part of the raw material, when kneading crushed coal and water or crushed carbon and water and a desulfurizing agent for producing CWP.
The present inventors have experimentally clarified appropriate kneading conditions in which the coal particles and the water are in a homogeneous state in the manufactured CWP and the particle size distribution of the manufactured CWP is not significantly changed. Kneading energy E (kWh / ton-CW) that gives the degree of CWP kneading per unit weight of CWP
As defined in P), the range of E = 1 to 5 kWh / ton-CWP is the above-mentioned appropriate kneading condition.

When the CWP raw material is kneaded in the above-mentioned appropriate range, the increment of the cumulative weight ratio of the particles having a particle diameter of 0.02 mm or less before and after the kneading is in the range of 1 to 5% by weight.

On the other hand, when the kneading energy E was 1 kWh / ton-CWP or less, the produced CWP had a portion having poor fluidity and a portion having a large amount of water and easily separated. When the kneading energy E is 5 kWh / ton-CWP or more, the cumulative weight percentage increase of particles having a particle size of 0.02 mm or less before and after kneading exceeds 5% by weight,
The weight average diameter of the particles constituting P became fine and the fluidity was lost.

The kneading energy E given per unit weight of the CWP is the power consumption P (kW) at the time of kneading to C
The WP production amount, that is, a value obtained by dividing the total amount Q (ton / h) of the raw material amount supplied to the kneader can be expressed by the equation (1). E (kWh / ton-CWP) = P (kW) / Q (ton / h) (1) That is, as a concrete method of controlling the kneading machine so that the kneading energy E satisfies an appropriate range, the plant operation is performed. The consumed power P may be manipulated so that the kneading energy E satisfies an appropriate range according to the total amount Q of raw materials set as a condition. In order to change the power consumption P, the kneader rotation speed or the amount of CWP retained in the kneader may be adjusted. For example, in order to increase the power consumption P, the above-described object of the present invention can be achieved by increasing the rotation speed of the kneading machine or increasing the amount of CWP retained in the kneading machine.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. FIG. 1 is a system diagram of a CWP manufacturing apparatus, a supply apparatus, and a combustion apparatus suitable for implementing the present invention. The raw coal A in the raw coal bunker 1 is supplied from a feeder 21 to a coarse crusher 2, where it is crushed and then sent to a crushed coal hopper 3. A part of the crushed charcoal B is supplied to the conduit 3 by the feeder 22.
1 is supplied to the fine pulverizer 5 and the rest is fed by a feeder 23 driven by a motor 42 through a conduit 34 to a kneader 6
Supplied to The pulverized coal B is wet pulverized together with a predetermined amount of water D supplied from the conduit 32 in the pulverizer 5 to form a pulverized coal slurry.

The pulverized coal slurry is supplied to the kneader 6 through the conduit 33 by the pump 9. Limestone bunker 4
The limestone C in the inside passes through the conduit 35 by the feeder 24 driven by the motor 41, and the water D flows in the control valve 10.
After the amount of water injected is adjusted by, the water is supplied to the kneading machine 6 through the conduit 36.

Crushed coal B, pulverized coal slurry, limestone C described above
The raw materials of water and water D are mixed in the kneader 6 in the kneader motor 1
After being stirred and mixed by the rotary blade 14 driven by 1,
A CWP with a given moisture and particle size distribution is produced.
A gate valve opening / closing motor 19 is provided at the outlet 16 of the kneading machine 6.
A kneading machine outlet gate valve 15 driven by is provided and its opening is adjusted according to kneading conditions. The CWP manufactured as described above is put into the CWP tank 7.

On the other hand, a pressurized fluidized bed combustion furnace (hereinafter abbreviated as a furnace) 101 is housed in a pressure vessel 104. An air dispersion plate 105 is provided at the bottom of the furnace 101, and fluid medium particles 102 are filled on the air dispersion plate 105. Pressurized air 106
After being supplied into the pressure vessel 104, the combustion air 107
Is supplied into the furnace 101 through the air dispersion plate 105 to fluidize the fluidized medium particles 102 to form a fluidized bed 109.

CWP is pumped to the furnace 101 through the supply conduit 37 by the CWP pump 8, and the spray nozzle 17
Is supplied to the inside of the fluidized bed 109 and burned. The combustion gas is discharged through a space (freeboard) 110 above the fluidized bed 109, dust is removed by the cyclone 103, and then introduced into a gas turbine (not shown) through the conduit 108.

The coarse crusher 2 is set so that raw coal having a maximum diameter of about 50 mm can be crushed to a particle size of a weight average diameter of about 2 mm. For crushing the raw coal A, any kind of crusher may be used as long as it can crush to a predetermined particle size. A classifier (not shown) may be installed downstream of the coarse crusher 2 to adjust the maximum particle size of the crushed coal.

The crushed carbon B in the crushed carbon hopper 3 is distributed to the fine crusher 5 and the kneader 6 at a predetermined ratio by adjusting the number of rotations of the feeders 22 and 23. The distribution ratio is set according to the coal properties. Usually, about 20 to 30% by weight of the pulverized coal B is supplied to the fine pulverizer 5 and wet pulverized, mixed with the pulverized coal B in the kneader 6 as a pulverized coal slurry, and adjusted to an optimum particle size distribution as CWP. It

On the other hand, the amount of water in CWP is adjusted by the amount of water D supplied to the fine pulverizer 5 and the kneader 6. In this way, CWP is manufactured while maintaining the blending ratio of each raw material set according to the coal type.

Here, the mutual relationship around the kneading machine 6 for manufacturing the CWP will be described in detail. Rotor blades 14 in the kneading machine 6
A kneading machine motor 11 for driving the machine is provided with a power measuring device 12. The power measurement by the power measurement device 12 may be performed by using a power meter or a method of calculating from the torque received by the rotating shaft and the shaft rotation speed. The measured power consumption during CWP kneading is output to the controller 13. Furthermore, the feeder 23
A signal corresponding to the supply amount of each raw material from the motor 42 for driving the motor, the motor 41 for driving the feeder 24, the CWP pump 9 and the water injection control valve 10 is supplied to the raw material summation calculator 4
Output to 0. The total sum Q (equivalent to the CWP production amount) of the supply amount of each raw material calculated by the total raw material calculator 40 is output to the control device 13.

The controller 13 calculates the kneading energy E per unit CWP amount defined by the equation (1).
A control signal is output to the kneading machine motor 11 to change the rotation speed of the kneading machine 6 so that the calculated value E satisfies the appropriate range.

In the above apparatus, particles of dolomite or limestone C having a maximum diameter of about 3 mm are used as the desulfurizing agent. The kneading machine 6 and the rotary blades 14 in FIG. 1 are schematically shown, and the present invention is not limited to the illustrated ones.

[0028]

The present invention will be described in detail below with reference to examples. Example 1 A CWP of Australian coal (constant humidity water = 3%, fuel ratio = 1.5) was manufactured using the equipment shown in FIG. FIG. 2 is an operation trend chart of the kneading machine at this time. As shown in the trend b, the total amount Q (tons / hour) of the raw materials supplied to the kneading machine 6 is a constant value, and is controlled almost as set value. However,
In this case, kneading energy E per unit weight of CWP
(KWh / ton-CWP) remained higher than the target value as shown by trend a. Therefore, at times t _l and t ₂
At that time, the rotation speed (rpm) of the kneading machine 6 was controlled stepwise (trend d), and the kneading power (kW) was reduced accordingly (trend c).

As a result, the kneading energy E shown in trend a satisfied the target value. In the operation of this example, the opening degree (%) of the kneading machine outlet gate valve 15 was kept constant, as indicated by the trend e.

Here, an index of kneading degree set as a target value, kneading energy E given per unit weight of CWP
Is experimentally clarified. The content that led to the finding of the proper range of the kneading energy E based on the experimental data will be described.

FIG. 3 shows the particle size distribution of various CWPs produced by changing the blade rotation speed of the rotor blade 14 during kneading. It can be seen that as the kneading energy E increases, the fine particle content increases and the particle diameter (weight average diameter) corresponding to a cumulative weight ratio of 50% decreases.

Table 1 summarizes the changes in the particle size distribution of CWP with changes in the kneading energy E at this time.

[Table 1]

The fine particle content of CWP is expressed by the cumulative weight ratio of particles having a particle size of 0.02 mm or less, and is 0.
The increment (wt%) of the cumulative weight ratio of particles having a particle diameter of 02 mm or less and the weight average diameter (mm) are also shown. The viscosity (Pa · s) of the manufactured CWP is also shown.

With respect to the initial state before kneading (E = 0), 0.02 mm at kneading energy E = 0.5 kWh / ton.
The cumulative weight percentage and the weight average diameter of particles having the following particle diameters hardly change, but the CWP viscosity is abnormally high. This is because the kneading is insufficient. On the other hand, when the kneading energy E is increased from more than 5 kWh / ton to 10 kWh / ton, the increment of the cumulative weight ratio of particles having a particle diameter of 0.02 mm or less with respect to the initial value reaches 12% by weight, and the weight average diameter Becomes as small as 0.6 mm. As a result, the CWP viscosity increases significantly.

FIG. 4 is an explanatory diagram showing the relationship between CWP water content and CWP viscosity. CWP If the water content decreases, CWP
The viscosity increases. Viscosity range where pumping is not possible (20
7) in normal operation so that
The target viscosity is set in the range of 10 Pa · s. Also, CW
When the weight average diameter of the particles constituting P becomes small, CWP
The CWP viscosity increases under a constant water content. in this case,
In order to satisfy the above-mentioned target viscosity range, it is necessary to increase the CWP water content.

FIG. 5 shows the experimental data shown in FIG. 4 and Table 1 as a relationship between the kneading energy E (kWh / ton-CWP) and the CWP water content. Here, the CWP viscosities were compared under constant conditions. It is understood that the range of kneading energy E = 1 to 5 kWh / ton-CWP in which the CWP water content does not increase is the proper kneading condition for producing the fuel for the pressurized fluidized bed boiler. From Table 1, it can be seen that in this range, the increment of the cumulative weight ratio of particles having a particle size of 0.02 mm or less before and after kneading is in the range of 1 to 5% by weight.

From the above examination, the kneading machine 6 is used so that the increment of the cumulative weight ratio of the particles constituting the CWP having a particle diameter of 0.02 mm or less is within the range of 1 to 5% by weight before and after the kneading. It becomes possible to obtain a CWP having fluidity with a smaller amount of water by operating.

Embodiment 2 FIG. 6 shows a system diagram of this embodiment. In FIG. 6, members having the same functions as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. FIG. 6 shows the control of the CWP kneading degree by the kneading machine 6
It is a configuration when the opening degree of the kneading machine outlet gate valve 15 is used instead of the rotation speed of. Further, in the present embodiment, the load command of the boiler is directly output to the control device 13 to calculate the CWP production amount, and the kneading energy E is calculated from the measured power value of the kneading machine 6.

From the controller 13 to the kneading machine outlet gate valve 15
A control signal is output to the gate valve opening / closing motor 19 that drives the kneading machine outlet gate valve 15 so that the calculated kneading energy E falls within a certain range. As a result, it becomes possible to operate the kneading machine 6 which secures fluidity with a smaller amount of water.

Embodiment 3 FIG. 7 shows a system diagram of this embodiment. In FIG. 7, members having the same functions as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. FIG. 7 shows the viscosity of a CWP produced by the kneading machine 6, a viscosity measuring device 18 installed at the kneading machine outlet 16.
In the configuration, the rotation speed of the kneading machine motor 11 or the kneading machine outlet gate valve 15 is operated based on the measured value. CWP of Australian coal (constant humidity water = 3%, fuel ratio = 1.5) was manufactured using the equipment shown in FIG.

FIG. 8 is an operation trend chart of the kneading machine 6 at this time. Although not shown here, the kneading machine 6
The total amount Q of the raw material supplied to is controlled almost as set value. However, as shown in trend f, manufacturing CWP
The viscosity of the sample remained higher than the target value. Therefore, the rotational speed of the kneading machine 6 was controlled stepwise (trend g) at times t ₃ , t ₄ and t ₅ , and the kneading power was reduced accordingly. As a result, the measured CWP viscosity indicated by trend f satisfied the target value.

Example 4 A CWP of Australian coal (constant humidity water = 3%, fuel ratio = 1.5) was manufactured using the equipment shown in FIG. FIG. 9 is an operation trend chart of the kneading machine 6 at this time, and shows a case where the opening degree of the kneading machine outlet gate valve 15 is adjusted to control the CWP viscosity. The total amount Q of raw materials supplied to the kneading machine 6 is constant,
It is controlled almost according to the set value. However, as indicated by trend h, the viscosity of the manufactured CWP remained higher than the target value. Therefore, at times t ₆ and t ₇ , the opening degree of the kneading machine outlet gate valve 15 is adjusted stepwise (trend j), and the CWP residence time in the kneading machine 6 is reduced accordingly (trend i). . As a result, the measurement value of the CWP viscosity at time t ₇ after as shown by the trend h has satisfied the target value.

Example 5 FIG. 10 is an operation trend chart when the operating conditions of the kneading machine 6 are changed in response to changes in the boiler load.
To 70% boiler load of 100% at time t _8, the load reduction instruction from 70% at time t ₉ to 50% are output (Bok trend k). In response to this, in the CWP manufacturing facility, the furnace 10
The CWP supply amount (trend 1), the CWP production amount (trend m), and the total amount of raw materials supplied to the kneading machine 6 (trend o) are sequentially decreased.

The kneading machine 6 without decreasing the rotation speed of the kneading machine 6
In contrast to the conventional method in which the operation of No. 1 was continued (trend q), in the method of the present invention, the rotation speed of the kneading machine 6 was changed according to the boiler load as shown by trend p, so that it was necessary and sufficient. Kneading was done.

Embodiment 6 FIG. 11 shows a system diagram of this embodiment. In addition, in FIG. 11, members having the same functions as those in FIG.
The description is omitted. In FIG. 11, in response to the load command of the boiler, the load command is directly output to the control device 13, or the load command is once output to the CWP pump controller 20, and then the CWP pump 8 transports the load command through the conduit 37.
This is an example in which the kneader 6 is operated by at least one of outputting the control value of the CWP pump 8 from the CWP pump controller 20 to the controller 13 after controlling the supply amount of WP. In the kneading device 13, the kneading energy E is calculated, and the rotation speed of the kneading machine 6 is controlled so that the value falls within the range of 1 to 5 kWh / ton-CWP.

As described above, according to the present invention, the CWP
Can be stably supplied with a smaller amount of water, and high plant efficiency can be maintained. In particular, it is possible to manufacture a CWP having extremely stable properties when the load on the plant changes.

[Brief description of the drawings]

FIG. 1 is a system diagram of an embodiment of the present invention.

FIG. 2 is a trend chart of kneading machine operation in one embodiment of the present invention.

FIG. 3 is a graph showing the relationship between the particle size of CWP and the cumulative weight ratio with respect to the rotation speed (kneading energy) of various kneading machines of the present invention.

FIG. 4 is a diagram showing a relationship between CWP water content and CWP viscosity of the present invention.

FIG. 5 is a diagram showing the relationship between kneading energy and CWP water content of the present invention.

FIG. 6 is a system diagram of an embodiment of the present invention.

FIG. 7 is a system diagram of an embodiment of the present invention.

FIG. 8 is a trend chart of kneading machine operation in one example of the present invention.

FIG. 9 is a trend chart of kneading machine operation in one example of the present invention.

FIG. 10 is a trend chart of kneading machine operation in one embodiment of the present invention.

FIG. 11 is a system diagram of an embodiment of the present invention.

[Explanation of symbols]

1 Raw coal bunker 2 Coarse crusher 3 Crushed coal hopper 4 Limestone bunker 5 Fine crusher 6 Kneader 7 CWP tank 8 CWP pump 9 Pulverized coal slurry pump 10 Control valve 12 Power measuring device 13 Controller 14 Rotor blade 15 Kneader outlet Gate valve 17 Spray nozzle 18 Viscosity measuring device 19 Gate valve opening / closing motor 40 Raw material summation calculator 101 Pressurized fluidized bed combustion furnace 102 Fluid medium particle 104 Pressure vessel 105 Air dispersion plate A Raw coal B Crushed carbon C Limestone D Water

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasutsune Katsuta 3-36 Takaracho, Kure City, Hiroshima Prefecture Babcock-Hitachi Kure Research Institute

Claims (14)

[Claims] 1. A method for producing a pressurized fluidized bed boiler fuel, comprising kneading pulverized coal and water, or pulverized coal and water and a desulfurizing agent to prepare a coal / water mixed fuel, which is then supplied to a pressurized fluidized bed boiler. The increase in the cumulative weight ratio of the particles having a particle size of 0.02 mm or less in the particles constituting the
A method for producing a fuel for a pressurized fluidized bed boiler such that the content of the fuel is in the range of% by weight. 2. A method in which crushed coal and water or crushed carbon and water and a desulfurizing agent are kneaded in a kneader to obtain a coal / water mixed fuel, and the fuel is supplied to a pressurized fluidized bed boiler, An increase in the cumulative weight ratio of particles having a particle diameter of 0.02 mm or less among the particles constituting the fuel is 1 to 5 before and after kneading.
A method for operating a kneading machine, which comprises operating the kneading machine so that the content of the kneading machine is in the range of% by weight. 3. A particle diameter of 0.02 mm or less among particles forming fuel by adjusting at least one of the number of revolutions of a stirring blade of the kneader and the opening degree of a gate valve provided at the kneader outlet. 3. The method for operating a kneading machine according to claim 2, wherein the increase in the cumulative weight ratio of the particles having the above is set in a range of 1 to 5% by weight before and after the kneading. 4. The fuel is constituted based on the kneading energy per unit amount of fuel (kWh / ton-fuel) which is a value obtained by dividing the measured power consumption in the kneading machine by the production amount of the coal / water mixed fuel. The increase in the cumulative weight ratio of particles having a particle size of 0.02 mm or less in the particles is 1 to 5% by weight before and after kneading.
The method of operating a kneading machine according to claim 3, characterized in that 5. The kneading machine operating method according to claim 4, wherein the kneading energy per unit coal / water mixed fuel amount is controlled to be 1 to 5 kWh / ton-fuel. 6. Based on the deviation between the measured value and the set value of the fluidity of the coal-water mixed fuel, the 0.
4. The kneading machine operating method according to claim 3, wherein the increment of the cumulative weight ratio of particles having a particle diameter of 02 mm or less is set to be in the range of 1 to 5% by weight before and after kneading. 7. Based on the boiler load change command, the increment of the cumulative weight ratio of particles having a particle diameter of 0.02 mm or less among the particles constituting the fuel is in the range of 1 to 5% by weight before and after kneading. The method of operating a kneader according to claim 3, wherein 8. A method for operating a pressurized fluidized bed boiler, which comprises supplying the pressurized fluidized bed boiler after kneading the pulverized coal and water or the pulverized coal and water and a desulfurizing agent to obtain a coal / water mixed fuel, and then loading the boiler load. Based on the change command, the fuel supply amount for supplying the coal-water mixed fuel obtained by kneading to the pressurized fluidized bed boiler is controlled, and 0.02 mm or less in particles forming the fuel based on the fuel supply amount. The method for operating a pressurized fluidized bed boiler, wherein the increment of the cumulative weight ratio of particles having the particle size of is set to be in the range of 1 to 5% by weight before and after kneading. 9. A kneader for producing fuel for a pressurized fluidized bed boiler, which is used when kneading crushed coal and water or crushed coal and water and a desulfurizing agent to prepare a coal-water mixed fuel, which is provided inside the kneader. The fuel is constituted by adjusting at least one of the rotational speed of the stirring blade for kneading the crushed coal and water or the crushed carbon and water and the desulfurizing agent, and the opening degree of the gate valve provided at the kneader outlet. 0.02 mm in particles
Pressurization characterized by having a control means for controlling the kneading degree of the kneader so that the increment of the cumulative weight ratio of the particles having the following particle diameters is in the range of 1 to 5% by weight before and after kneading. Kneader for fuel production for fluidized bed boiler. 10. A means for measuring power consumption in a kneader, and a kneading energy per unit amount of fuel, which is a value obtained by dividing the measured value of power consumption by the means by the production amount of coal / water mixed fuel. The means for calculating (kWh / ton-fuel) is provided, and the control means for controlling the kneading degree of the kneader based on the calculated value of the calculating means controls the operation of the kneader. Kneader for fuel production for pressurized fluidized bed boiler. 11. The control means for controlling the kneading degree of the kneading machine is controlled so that the kneading energy per unit coal / water mixed fuel amount calculated by the calculating means is 1 to 5 kWh / ton-fuel. A kneader for producing fuel for a pressurized fluidized bed boiler according to claim 10. 12. A means for measuring the fluidity of a coal / water mixed fuel, and a calculating means for calculating a deviation between the measured value and a set value, the kneading degree of a kneading machine based on the calculated value of the calculating means. 10. The kneader for producing fuel for a pressurized fluidized bed boiler according to claim 9, wherein the control means for controlling the kneader controls the operation of the kneader. 13. The pressurizing apparatus according to claim 9, wherein the control means for controlling the kneading degree of the kneading machine receives the boiler load change command and controls the operation of the kneading machine based on the load change signal. Kneader for fuel production for fluidized bed boiler. 14. A kneader for kneading crushed coal and water or crushed coal, water and a desulfurizing agent to obtain a coal / water mixed fuel, and a pressurized fluidized bed boiler for the coal / water mixed fuel obtained by the kneader. In a pressurized fluidized bed boiler equipped with a coal / water mixed fuel supply unit consisting of a fuel pump, etc., for mixing the crushed coal and water or the crushed coal and water and a desulfurizing agent inside the kneader. 0.02 mm in the particles forming the fuel by adjusting at least one of the rotation speed of the stirring blade and the opening degree of the gate valve provided at the kneader outlet.
A control means for controlling the kneading degree of the kneader so that the increment of the cumulative weight ratio of the particles having the following particle diameters is in the range of 1 to 5% by weight before and after the kneading, and the coal obtained by the kneader. A fuel pump control means for controlling a fuel supply amount of the water-mixed fuel to the pressurized fluidized bed boiler, the fuel pump control means receiving a boiler load change command;
A pressurized fluidized bed boiler, wherein a control means for calculating and outputting a fuel pump control amount and controlling the kneading degree of the kneader controls the kneading degree of the kneader based on the fuel pump control amount.