JPH07228878A - Apparatus for controlling kneading of coal/water mixture - Google Patents

Abstract

PURPOSE:To provide a kneading controller capable of efficiently kneading a mixture (CWP) of homogeneous coal with water, excellent in responsiveness and capable of carrying out control of its properties. CONSTITUTION:Crushed coal B is fed to a kneader 118 and a controlling agent C (either one or both of water and pulverized coal) is fed through the interior of a hollow rotating shaft 2 from a discharge hole 4. When the properties of CWP are detected in a CWP feed pipe and kneading and control of CWP are carried out, CWP torque detecting means is provided on the rotating shaft 2 and the controlling agent C is fed from the discharge hole 4 on the rotating shaft 2 side on the upstream side of a CWP kneading part to CWP kneading part to carry out property control of CWP. When the rotating shaft 2 having an agitating blade 127 mainly kneading the mixture and the rotating shaft 2 not shown in the figure and driving a means for detecting agitating torque of the mixture are respectively independently provided, stable control having good responsiveness can be carried out, because resistance loaded by the agitating blade 127 does not become a factor changing an agitating torque value in a torque detecting part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for producing and supplying a coal / water mixture, and more particularly to a kneading / adjusting device for coal / water paste fuel which can be stably supplied to a combustion furnace.

[0002]

2. Description of the Related Art Coal is burned in a pressurized fluidized bed boiler to generate steam for power generation by a steam turbine, and a high pressure, high temperature combustion gas generated in a fluidized bed furnace of the pressurized fluidized bed boiler is used to generate a gas turbine. A pressurized fluidized bed boiler combined cycle power plant that drives and generates power is known. As the method of supplying coal to the fluidized bed furnace of pressurized fluid Doso boiler, a mixture of coal particles and water pasty fluid (hereinafter, C oal- W
ater P aste; abbreviated as CWP)
There is a wet supply method in which the pressure is increased and pumped by a pump to supply it to a spray nozzle of a fluidized bed furnace. However, the CWP
It is necessary to reduce the water content in the water as much as possible in order to maintain high power generation efficiency. CW with limited amount of added water
P has a problem that it has a high viscosity and is poor in fluidity because a chemical for dispersing coal particles is not added in order to reduce the manufacturing cost. In order to obtain a CWP having good fluidity, not only the water content adjustment but also the particle size composition adjustment is important. That is, in order to obtain a CWP having good fluidity, it is necessary that the coal particles in the CWP exist in a wide range of particle sizes from fine particles of several tens of μm to coarse particles of maximum 10 mm.

In order to stably transport CWP under the above constraints, the viscosity of CWP is 5 Pa · s to 20 Pa.
・ It is desirable to adjust to the range of s. When the viscosity of CWP is 20 Pa · s or more, there is a problem that the CWP is likely to be clogged and water separation phenomenon occurs at the suction port of the pump, and the CWP cannot be sucked by the pump. On the other hand, the viscosity of CWP is 5 Pa · s
If it is lower, there is a problem that coarse particles settle and block in the pipe. The amount of water in the CWP and the particle size composition of the coal are factors that affect the viscosity of the CWP, and the viscosity obtained thereby greatly changes. Therefore, in order to adjust the properties of CWP, it is sufficient to adjust the water content and particle size composition in CWP.

As a method for producing CWP, as shown in FIG. 11, pulverized coal B, water D and desulfurizing agent E are supplied from a raw material inlet 128 of a kneading device 118, and a stirring blade 127 driven by a motor 126 is used to carry out the above-mentioned process. Knead the raw materials. The kneaded coal / water paste (CWP) is sent from a chute 129 to a storage tank (not shown) over the weir 130 (see Japanese Patent Laid-Open No. 62-155433). Further, as a method for adjusting the CWP property when manufacturing CWP and supplying it to the pressurized fluidized bed boiler, conventionally, as shown in FIG.
22 and the CWP supply pump 124 driven by the hydraulic device 125 to the hollow rotary shaft 2 in the CWP channel 1
The torque detector 7 is provided, and the control device 12 supplies water from the pipe wall of the conduit of the storage tank 122 while adjusting the supply amount of water or pulverized coal or pulverized coal slurry, and kneads the mixture. A method has been proposed (see Japanese Patent Application No. 5-67026).

[0005]

[Problems to be Solved by the Invention] However, CWP
When kneading water, pulverized coal, etc. according to the stirring torque value of, since the water content of CWP itself is low and the viscosity is high, the coal particles in the fine particle region are difficult to mix with water, and the coal particles and water are homogeneously present. CWP could not be manufactured. Even when the present inventors use the CWP property adjusting device disclosed in Japanese Patent Application No. 5-67026, water, pulverized coal slurry, etc. (hereinafter referred to as adjusting agent) are supplied according to the detected stirring torque of CWP. Since the viscosity of CWP at that time is high, the modifier is difficult to mix and disperse in CWP. When trying to mix the adjusting agent efficiently, a large number of adjusting agent supply ports are required, which causes a problem that the adjusting agent supply line becomes complicated and the cost increases. Also, the regulator supplied to the CWP is CW
It was unevenly distributed in the vicinity of the P channel pipe wall, and it did not easily reach the center of the pipe line, so that a quick CWP property improving effect could not be obtained. As a result, there is a large time delay in the detection of the stirring torque in the CWP flow path downstream of the adjusting agent supply port, and good CW is achieved.
The P property could not be adjusted. In addition, there is a problem that the detected value has a large temporal variation and it is difficult to accurately detect the value.
As a result, there has been a problem that the detected value has a large variation with time and accurate detection is difficult. As a result, there is a problem that the viscosity of the CWP is extremely lowered and causes blockage in the supply pump 124. An object of the present invention is to provide a kneading adjusting device for efficiently kneading a homogeneous mixture of coal and water and adjusting the properties thereof. In particular, for a method of detecting the properties of CWP in the CWP supply flow channel, and kneading and adjusting the properties, it is an object of the present invention to provide a kneading adjusting device for coal / water mixture which is capable of adjusting the properties with excellent responsiveness.

[0006]

The above objects of the present invention can be achieved by the following constitutions. That is, in a coal / water mixture kneading adjusting device for kneading coal and water to prepare a coal / water mixture, a raw material charging port for supplying crushed coal is provided on the upstream side of the coal / water mixture kneading section, and has a hollow structure. At the tip of the hollow portion of the rotary shaft for kneading the coal / water mixture, a regulator supply conduit for supplying a regulator made of at least one of water and pulverized coal slurry for adjusting the properties of the coal / water mixture is connected, and the hollow It is a kneading / adjusting device for a coal / water mixture, which is provided with an outflow hole on the surface of a rotating shaft for letting out the adjusting agent supplied to the inside of the part into the coal / water mixture during kneading or property adjustment. The hollow rotating shaft of the coal / water mixture kneading adjusting device is provided with an outflow hole on the side surface of the hollow rotating shaft in the upstream region of the kneading section,
Further, a stirring blade for kneading the coal / water mixture can be provided.

The above object of the present invention is achieved by the following configurations. That is, in a coal / water mixture kneading adjusting device for kneading coal and water to prepare a coal / water mixture, a raw material charging port for supplying crushed coal is provided on the upstream side of the coal / water mixture kneading section, and has a hollow structure. At the tip of the hollow part of the rotary shaft for kneading the coal / water mixture, a conditioner supply conduit for supplying a conditioner containing at least one of water for property adjustment and pulverized coal slurry is connected, and the inside of the hollow part is supplied. An outlet hole for letting out the adjusting agent into the coal / water mixture during kneading or property adjustment, and a stirring blade for kneading the coal / water mixture are provided on the surface of the rotary shaft, and the mixture is fed using the stirring blade. A torque detector that detects the stirring torque of the coal / water mixture, and a regulator supply amount control device that controls the supply amount of the regulator through the hollow portion of the hollow rotary shaft according to the torque detection value of the coal / water mixture. Coal / water mixture provided A kneading adjustment device. The hollow rotary shaft of the coal / water mixture kneading adjusting device may be provided with an outflow hole on the side surface of the hollow rotary shaft in the upstream region of the kneading section. Further, the hollow rotating shaft of the coal / water mixture kneading adjusting device is mainly a hollow rotating shaft equipped with a stirring means for kneading the coal / water mixture and a stirring means mainly for detecting stirring torque of the coal / water mixture. The hollow rotary shafts provided with can also be independently configured.

[0008]

[Function] Coal / water mixture with low water content has high viscosity,
In the first place, it is difficult to knead. According to the present invention, in such a high viscosity state of the coal / water mixture, the adjusting agent (water or pulverized coal slurry) is introduced into the surrounding coal / water mixture through the outflow holes on the surface of the hollow rotating shaft of the kneading adjusting device which rotates. Can be supplied efficiently. Further, the supplied adjusting agent (water or fine particle slurry) is forcibly dispersed by a stirring blade installed near the outflow hole. The present invention can be applied not only to a device for kneading a coal / water mixture, but also to an adjusting device for adjusting the CWP property provided between the kneading device and the CWP tank or in the CWP supply conduit section immediately after the CWP tank. it can. In this case, it operates as follows.

The flow of the coal-water mixture in the feed conduit is laminar, with the highest velocity in the central part of the conduit. According to the present invention, the adjusting agent is supplied from the inside of the hollow rotating shaft to the central portion of the CWP supply conduit, so that the supplied adjusting agent is supplied from the upstream side of the rotating shaft to the downstream side by the flow of the coal-water mixture in the conduit. Get propulsion in the side direction. On the other hand, since the adjusting agent outflow hole rotates together with the rotating shaft, the adjusting agent can be efficiently dispersed around the rotating shaft, and a mixing effect equal to or more than that having a large number of adjusting agent outflow holes can be obtained. That is, in the present invention, the property is improved in a shorter time than in the case where the adjusting agent is supplied from the wall surface of the flow path of the CWP supply conduit as in the conventional method. In the CWP kneading adjusting device of the present invention, the stirring blade for mainly kneading CWP and the stirring blade for driving torque for CWP are made independent to each other, so that the stirring blade mainly for CWP kneading is provided. Since the resistance received at is not detected by the torque detector,
The modifier can be positively mixed and dispersed in the stirring unit for kneading the CWP. As a result, there is almost no fluctuation in the stirring torque value at the torque detection unit, and responsive and stable control is performed.

[0010]

EXAMPLES The present invention will be described in detail below with reference to examples. FIG. 1 shows a schematic cross-sectional view of the kneading device of this example. From the raw material inlet 128 of the kneading device 118, crushed coal B, water D
Then, the desulfurizing agent E is supplied, and the raw materials are mixed by the stirring blade 127 of the hollow rotary shaft 2 driven by the motor 126. At this time, the conduit 5 for supplying the pulverized coal slurry C, which is the property modifier for the coal / water mixture, is connected by the joint 9 to the stirring blade 127.
Is connected to the hollow rotary shaft 2. The pulverized coal slurry C is supplied from the outflow hole 4 into the kneading device 118 through the inside of the conduit 5 and the hollow rotating shaft 2, and is then fed into the kwp (coal / water paste).
Is obtained. FIG. 2 shows a system diagram of a CWP manufacturing / supplying device using the kneading device of FIG. Raw coal A in raw coal bunker 101
Are supplied to the vibrating screen 104 by the table feeder 102. A screen 105 is installed on the vibrating screen 104, and the raw coal A on the screen 105 is crushed by the coarse crusher 10.
It is crushed in 6 and returned to the vibrating screen 104 again. Coarse pulverized coal B that passed through the screen 105 in the vibrating screen 104
The (coarse particles having a particle size of about 6 mm or less) are transferred to the quantitative feeder 112 by the conveyor 107. On the other hand, the raw coal bunker 101 is further provided with a quantitative feeder 103,
Raw coal A cut out by the quantitative feeder 103 is a fine crusher 1
At 08, wet pulverization is performed together with a predetermined amount of water D to produce a pulverized coal slurry C. This crushed coal slurry C is in tank 119
After being temporarily stored in the kneading machine, it is supplied by the pump 120 to the kneading device 118 via the supply conduit 5.

The raw coal A is weighed by a weighing device 109 and a weighing device 110, respectively, and the control device 111 determines the amount to be distributed to the pulverized coal B and the pulverized coal slurry C. A coal weighing device 114 is installed in the fixed quantity feeder 112, and
The weight of the coal containing water in the coal in 2 is continuously detected. The coal measured by the quantitative feeder 112 is the motor 11
In 3, the supply amount is controlled and sent to the kneading device 118. In the kneading device 118, coarse coal B cut out by the quantitative feeder 112, pulverized coal slurry C supplied by the pump 120, water D supplied by the water supply valve 117, and limestone E cut out by the limestone feeder 116 from the limestone tank 115. Are added, stirred and mixed to obtain C
WP is manufactured. CWP manufactured in this way
Is the flow path 1 between the kneading device 118 and the CWP tank 122.
After being transferred inside, it is agitated by an agitator 123 provided in the CWP tank 122. CWP tank 122 and hydraulic system 1
The CWP pump 124 driven by 25 is connected through the flow path 11, and the CWP pump 124 produces C
The WP is pumped to a furnace (not shown). In the flow path 1, the rotary shaft 2 is rotated by the motor 6 via the torque detector 7. The measured torque value detected here is compared with a torque set value signal preset in the control device 12, and the pulverized coal slurry C is torqued by the slurry pump 121 via the supply conduit 5 so as to reduce this deviation. It is supplied to the detection unit provided with the detector 7. A torque detecting means similar to the torque detector 7 may be provided in the flow path 11 and is particularly effective when the tank 122 becomes large.

FIG. 3 shows an enlarged view of the CWP adjusting device according to this embodiment. The CWP property adjusting device provided in the flow path 1 includes a rotating shaft 2 having a hollow inside, a stirring blade 3, a motor 6 for driving the hollow rotating shaft 2, and a torque detector 7 received when the stirring blade 3 is stirred. It is configured. The hollow rotating shaft 2 is fixed to the flow path 1 by a bearing 8. The hollow rotary shaft 2 is connected to the supply conduit 5 for supplying the pulverized coal slurry C by a joint 9 so that the pulverized coal slurry C, which is an adjusting agent, can be supplied into the hollow rotary shaft 2. To control CWP properties online, use CW after supplying the modifier.
It is necessary to detect again in a short time whether P is the target property. The stirring blade 3 rotating with the rotating shaft 2 is C
Although it receives agitation resistance from WP, if the agitation blade 3 is installed in the flow path 1, there is almost no area in the flow path 1 that is not agitated, so the pulverized coal slurry C to be supplied should be adjusted to C
It is dispersed in WP for a short time. Further, since the rotary shaft 2 has a hollow structure, the pulverized coal slurry C is inserted through the rotary shaft 2.
Can be supplied to the central portion of the flow channel 1. That is, when the pulverized coal slurry C is supplied to the vicinity of the central portion of the flow passage 1 from the plurality of outflow holes 4 provided at appropriate places on the side surface of the rotary shaft 2, the flow velocity of CWP in the central portion of the flow passage 1 is used. Thus, the mixing and dispersion of the CWP in the flow direction is realized. At the same time, the pulverized coal slurry C outflow hole 4 rotates together with the rotary shaft 2, so that the pulverized coal slurry C can be efficiently dispersed around the rotary shaft 2 and the same or more mixing than the case where a large number of supply conduits 5 are provided. The effect can be obtained with a single supply conduit 5.

FIG. 4 shows how the pulverized coal slurry C flows out through the outflow holes 4. The outflow hole 4 is provided as close as possible to the stirring blade 3 so that the pulverized coal slurry C supplied from the outflow hole 4 into the flow path 1 is forcibly dispersed in the CWP. As described above, the pulverized coal slurry C is added to the hollow rotary shaft 2
If it is supplied to the central portion of the flow channel 1 via the above, the CWP flow velocity in the central portion of the flow channel 1 is utilized to realize mixing and dispersion in the CWP flow direction. At the same time, the outflow hole 4 of the pulverized coal slurry C rotates together with the rotary shaft 2, so that the pulverized coal slurry C can be efficiently dispersed around the rotary shaft 2. FIG. 5 shows the effect of improving the response in the mixing apparatus of the present invention in comparison with the conventional method. When the pulverized coal slurry C is supplied in a predetermined amount according to the change in the CWP property, the target stirring torque is reached in a short time in the method of the present invention as shown by the curve a. On the other hand, in the conventional method, the supplied pulverized coal slurry C is less likely to be mixed with CWP, so that it takes a considerable time to obtain the target stirring torque as shown by the curve b. Further, in some cases, there is almost no mixing, and there is a case where no change appears in the detected value in the property like the curve c. In the case of the curve c, since the regulator is excessively supplied, C
The viscosity of the WP drops dramatically causing blockage at the pump 124 (FIG. 2). In the present embodiment, the pulverized coal slurry C is supplied from the opposite side of the motor 6, but the same effect can be obtained by supplying the pulverized coal slurry C from the motor 6 side as shown in FIG.

FIG. 7 shows an example in which the supply conduit 5 for the pulverized coal slurry C is inserted inside the hollow rotary shaft 2 in the flow path 1.
In this embodiment, the inner diameter of the supply conduit 5 can be made as small as possible, and the initial velocity of the pulverized coal slurry C flowing out from the outflow hole 4 can be increased. As a result, the penetrating force of the pulverized coal slurry C flow into the CWP in the flow path 1 is increased, and the dispersion of the pulverized coal slurry C into the CWP is accelerated. FIG. 8 shows another embodiment of the CWP kneading device according to the present invention. In this embodiment, the water D is used as the flow path 1
There is an independent portion for supplying and stirring to the CWP inside and a portion for detecting the stirring torque of the CWP after stirring. Water D, which is an adjusting agent, is supplied to the hollow rotating shaft 15 equipped with a screw-shaped stirring blade 16 through the supply conduit 5. The hollow rotary shaft 15 has a function of being rotated by the motor 12 at high speed. Outflow hole 4 in which water D opens on the side surface of hollow rotary shaft 15
Is supplied to the CWP in the flow path 1 from the above, and at the same time, is strongly stirred by the stirring blade 16 rotating at a high speed. At this time, CW
Part of the coal particles present in P are crushed to generate fine particles. That is, there is an effect that the generated coal fine particles contribute to the improvement of the properties of CWP.

FIG. 9 shows an embodiment in which the CWP is manufactured by the batch method. The crushed carbon B and the desulfurizing agent E are supplied from a raw material inlet 25 of the kneading device 20, and the raw materials are mixed by a stirring blade 22 driven by a motor 21. At this time, the pulverized coal slurry C is supplied to the kneading device 20 from the outflow hole 23 through the conduit 24 and the inside of the hollow rotary shaft 28 connected by the joint 26, and CWP (coal / water paste).
Is obtained. After manufacturing CWP by batch method, kneading device 20
It is discharged as fuel from a discharge port 27 provided at the bottom of the.
FIG. 10 shows a CW manufactured by the kneading device 20 shown in FIG.
It is the result of comparing the time change of the kneading degree of P with the conventional example.
According to the method of the present invention, a high CW can be achieved in about 1/3 the time of the conventional method.
Since the kneading degree of P is obtained, the volume of the kneading device can be reduced, which is economical.

[0016]

As described above, according to the present invention, the coal / water mixture can be kneaded in a short time. It is possible to provide a coal / water mixture fuel supply facility capable of stably supplying CWP to a combustion furnace by reducing variations in fuel properties.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a CWP kneading adjustment device according to an embodiment of the present invention.

FIG. 2 is a system diagram of a CWP manufacturing / supplying device using the kneading adjusting device of FIG.

FIG. 3 is an enlarged view of the CWP kneading adjustment device of FIG.

FIG. 4 is a view for explaining a situation in which the adjusting agent flows out from an outflow hole of a hollow rotating shaft of the CWP kneading adjusting device of FIG.

FIG. 5 is a diagram of a comparative example regarding the responsiveness of the method of the present invention and the conventional method.

FIG. 7 is a schematic diagram of a CWP kneading adjustment device according to an embodiment of the present invention.

FIG. 8 is a schematic diagram of a CWP kneading adjustment device according to an embodiment of the present invention.

FIG. 6 is a schematic diagram of a CWP kneading adjustment device according to an embodiment of the present invention.

FIG. 9 is a schematic view of a batch-type kneading adjustment device according to the present invention.

FIG. 10 is a comparison diagram of a batch-type kneading adjusting device of the method of the present invention and a conventional method.

FIG. 11 is a schematic view of a conventional CWP kneading device.

FIG. 12: CW for conventional CWP storage tank and boiler
It is a schematic diagram of the kneading adjustment device of CWP provided in the CWP channel between P supply pumps.

[Explanation of symbols]

1, 11 ... CWP channel, 2, 15, 28 ... Hollow rotating shaft,
3, 16, 22, 127 ... Stirring blades, 4, 23 ... Outflow holes, 5 ... CWP supply conduit, 6 ... Motor, 7 ... Torque detector, 8 ... Bearing, 9, 26 ... Joint, 12 ... Control device, 20 , 118 ... Kneading device, 24 ... Pulverized coal slurry conduit, 25, 128 ... Raw material input port, 27 ... Discharge port, B ... Pulverized coal slurry, C ... Pulverized coal slurry, D ... Water, E ... Desulfurizing agent

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazunori Sato 3-36 Takaracho, Kure-shi, Hiroshima Babcock Hitachi Kure Laboratory Co., Ltd. (72) Katsuya Oki 6-9 Takaracho, Kure-shi, Hiroshima Babcock Hitachi Stock Company Kure Factory

Claims (5)

[Claims] 1. In a kneading and adjusting apparatus for a coal / water mixture for kneading coal and water to prepare a coal / water mixture, a raw material inlet for supplying crushed coal is provided upstream of a kneading section for the coal / water mixture. A connecting agent supply conduit for supplying an adjusting agent comprising at least one of water and pulverized coal slurry for adjusting the properties of the coal / water mixture is connected to the end of the hollow part of the rotary shaft for kneading the coal / water mixture having a hollow structure. A kneading adjustment of the coal / water mixture, characterized in that an outlet hole is provided on the surface of the rotating shaft for letting out the adjusting agent supplied into the hollow portion into the coal / water mixture during kneading or property adjustment. apparatus. 2. The outflow hole is provided on the side surface of the hollow rotary shaft in the upstream region of the kneading section, and the hollow rotary shaft is provided with coal.
The kneading adjustment device for coal / water mixture according to claim 1, further comprising a stirring blade for kneading the water mixture. 3. A coal / water mixture kneading adjusting device for kneading coal and water to prepare a coal / water mixture, wherein a raw material charging port for supplying crushed coal is provided upstream of a coal / water mixture kneading section. , A hollow structure coal / water mixture kneading rotary shaft for rotation of the shaft is connected to the adjusting agent supply conduit for supplying an adjusting agent consisting of at least one of water for property adjustment and pulverized coal slurry, inside the hollow portion An outlet hole for letting the adjusting agent supplied into the mixture into the coal / water mixture during kneading or property adjustment and a stirring blade for kneading the coal / water mixture are provided on the surface of the rotary shaft, and the stirring blade is used to flow the mixture. A torque detector that detects the stirring torque of the coal / water mixture to be sent, and a regulator supply amount that controls the supply amount of the regulator performed through the hollow portion of the hollow rotary shaft according to the torque detection value of the coal / water mixture. It is characterized by having a control device A kneading adjustment device for coal and water mixture. 4. The kneading / adjusting device for a coal / water mixture according to claim 3, wherein the outflow hole is provided on a side surface of the hollow rotating shaft in an upstream region of the kneading section. 5. A hollow rotary shaft mainly equipped with a stirring means for kneading a coal / water mixture and a hollow rotary shaft mainly equipped with a stirring means for detecting a stirring torque of a coal / water mixture are independent of each other. The kneading adjusting device for a coal / water mixture according to claim 3, wherein