JP2000266312A - Apparatus and method for dust removing for pressurized fluidized-bed boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent decrease in dust removing efficiency of a high temperature combustion exhaust gas by regulating a flowing speed of the gas entering a cyclone by a flow regulator based on smoke soot particle size distribution of the gas measured at an inlet of the cyclone, so that the distribution lies in a prescribed range. SOLUTION: An exhaust gas from a pressurized fluidized-bed boiler 1 is roughly removed of dust by a primary cyclone 7, precisely dust removed by a secondary cyclone 8, and supplied as a combustion exhaust gas to a gas turbine 10. Smoke dust is captured according to a particle size of the dusts by a cascade impactor 23 parallel with the cyclones 7, 8, weights are measured by a measuring instrument 24, and a particle size distribution is measured. When the particle size of the dust is increased, dampers of inlets of the cyclones 7, 8 are opened to decelerate the flowing speed of the gas, thereby preventing the wear of a castable material in the cyclone, while when the size of the dust is decreased, the damper is closed to accelerate the speed of the gas, thereby preventing decrease in dust collecting efficiency and preventing wear of the blade of the turbine 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dedusting apparatus for a pressurized fluidized-bed boiler, and more particularly, to a dedusting apparatus suitable for effectively reducing the concentration of dust in hot exhaust gas discharged from a pressurized fluidized-bed boiler. The present invention relates to a dust removing device and a dust removing method for a pressurized fluidized bed boiler.

[0002]

2. Description of the Related Art A pressurized fluidized bed boiler combined cycle power plant is
Instead of a pulverized coal combustion boiler, finely crushed coal is flow-combusted in a boiler under pressure, and the steam generated from water pipes laid in the fluidized bed drives the steam turbine and the high-pressure combustion discharged from the boiler The gas turbine is driven by the exhaust gas, and power is generated by both the steam turbine and the gas turbine. FIG. 21 is a system diagram of a pressurized fluidized-bed boiler combined cycle power plant according to the related art.

This combined cycle power plant comprises a pressurized fluidized bed boiler 1 for supplying coal to a fluidized bed to perform combustion, a steam turbine 2 for generating electric power by steam generated by the combustion, and Cyclones 7 and 8 for removing dust from the high-temperature exhaust gas discharged from the gas turbine, and a gas turbine 10 for generating power using the removed high-temperature exhaust gas. In such a configuration, steam generated by the combustion of coal in the pressurized fluidized-bed boiler 1 is supplied to the steam turbine 2, and power is generated by the steam turbine generator 3. The steam that has driven the steam turbine 2 is cooled by the condenser 4 and becomes boiler feedwater, and is supplied again from the feedwater pump 5 to the pressurized fluidized bed boiler 1 as boiler feedwater. The high-temperature and high-pressure dust-containing exhaust gas generated in the pressurized fluidized-bed boiler 1 is subjected to coarse dust removal from the high-temperature gas pipe 6 in the primary cyclone 7 and then to precision dust removal in the secondary cyclone 8. The gas discharged from the secondary cyclone 8 is supplied from a high-temperature gas pipe 9 to a gas turbine 10 to drive the gas turbine 10 and generate electric power by a gas turbine generator 11. Exhaust gas leaving the gas turbine 10 is cooled by an exhaust gas cooler 12, fine dust is removed by a low-temperature dust collector 13, and is discharged to the atmosphere from a chimney 14. In FIG. 21, reference numerals 15 and 16 denote storage containers for storing the primary cyclone 7 and the secondary cyclone 8, respectively, 17 denotes an air compressor, and 18 denotes an ash treatment device.

[0004] When the above-mentioned plant is operated, abrasion of the blades of the gas turbine 10 due to dust generated due to the combustion of coal becomes a problem. A cyclone type dust collector, which is a centrifugal dust collecting method that requires dust removal and can be used under high temperature and high pressure, is used. However, by using such a cyclone type dust collector, when burning using homogeneous coal, the dust concentration can be reduced to such an extent that the wear of the blades of the gas turbine 10 is not a problem. If the coal type is different, or if the particle size of the dust becomes smaller due to a change in the combustion state or the like, the dust collection performance decreases, so that the dust flowing into the gas turbine 10 increases, and the gas turbine 10
There is a problem of giving wear to the blade.

FIG. 22 is an explanatory view of a cyclone container used as a cyclone type dust collector and containing a plurality of cyclones. In FIG. 22, 800-900 ° C. with an ash concentration of several 10 g / Nm ³ containing, for example, combustion ash or limestone having an average particle size of several tens μm discharged from the pressurized fluidized bed boiler.
The high temperature dust-containing gas 39 is supplied to the cyclone element 32 at a flow rate of several tens of m / s, and is dedusted by the swirling of air therein, and the clarified gas is collected in the plenum 38 above the cyclone container 33, and The exhaust gas 40 is discharged outside the cyclone container. Ash 3 collected
5 is discharged from the lower hopper by gravity settling. However, in such a cyclone type dust collector, if the properties such as the particle size or dust concentration of the furnace scattered dust fluctuate during the operation of the plant, the cyclone itself is not provided with a function for adjusting the dust removal performance. However, there is a problem that the dust concentration in the exhaust gas from the cyclone outlet fluctuates. For this reason, conventionally, when the inlet dust concentration fluctuates in the increasing direction, the plant load is temporarily reduced to reduce the dust load in order to protect the gas turbine, or the plant is stopped to increase the cyclone. It was necessary to take measures such as replacing with efficient ones.

Further, since the inner wall of the cyclone is exposed to a gas having a high temperature of about 900 to 1000 ° C. containing erodible particles, an erosion-resistant refractory material is applied (Japanese Patent Laid-Open No. Hei 3 (1994)).
No. -89962). FIG. 23 is an enlarged explanatory view showing the refractory material structure of the inner wall of the cyclone. In FIG. 23, the refractory material 44 on the inner wall of the cyclone includes a plurality of studs 56 attached to the water wall pipe 54 and the fins 54 by welding.
And an anchor 53.
However, in such a structure, the refractory material 44 is only partially held by the anchor 53, and no measures are taken to prevent the refractory material surface from peeling or falling off. There was a problem that it was discharged from the cyclone outlet.

In the gas turbine power generation system, coal ash and limestone (quick lime) as a desulfurizing agent are contained in high-temperature and high-pressure exhaust gas (temperature: about 850 ° C., pressure: 8 to 10 atm) guided from the pressurized fluidized bed boiler to the gas turbine. Is also included),
There was a problem that gypsum produced by the desulfurization reaction was included, and these caused wear damage to equipment in the exhaust gas line (hereinafter, referred to as “gypsum”).
Coal ash, limestone, gypsum, etc. flying from the boiler are referred to as fly ash). The portions to be worn include high-temperature gas pipes, cyclones, blades of gas turbines, and the like, all of which are devices that require important functions. Conventionally, as a countermeasure against wear of these devices, a high-grade material with excellent wear resistance is selected, a design that takes into account the extra thickness for wear, and a structure that is easy to replace assuming that it will be replaced when wear occurs. And a method of reducing the flow rate of gas so that abrasion hardly occurs. However, according to the above-mentioned countermeasures, (1) hot gas piping must be installed in a commercial plant (25
(0 to 350 MW), the length is 200 to 300 m. Therefore, the use of high-grade materials and the method of increasing the excess wall thickness increase the plant manufacturing cost. (2) If the flow rate of the high-temperature gas There has been a problem that the diameter increases, the outer surface area increases, heat loss increases, the temperature at the gas turbine inlet decreases, and the gas turbine efficiency decreases.

Further, the conventional pressurized fluidized-bed boiler combined cycle power plant is provided with an emergency decompression facility for coping with the occurrence of an abnormality in the pressurized fluidized-bed boiler or the like. FIG. 24 is an explanatory diagram of an emergency decompression facility of a pressurized fluidized-bed boiler. In FIG. 24, during normal operation, the combustion air is supplied to the compressor 112
The air reaches the pressure vessel 102 through the air pipe 107. Further, the combustion air passes through a hot-air stove 103 for start-up,
Leads to. The combustion gas generated in the furnace 101 passes through a furnace outlet high-temperature gas pipe 105, a high-temperature and high-pressure dust remover 104, and a dust remover outlet hot gas pipe 106, and passes through the gas turbine 11.
Reaches 3. After driving the gas turbine 113, the decompressed and cooled combustion gas passes through the gas turbine outlet duct 114, the denitration device 115, and the exhaust heat recovery device 116, and is dedusted by a low-temperature low-pressure dedusting device such as a bag filter or an electric dust collector. And is released from the chimney 117 to the atmosphere. Reference numeral 103 denotes a track hot blast stove. On the other hand, in an emergency such as a boiler trip, the compressor 112 and the gas turbine 113 are isolated to decompress the entire system. That is, immediately after the trip, the compressor outlet valve 112 and the gas turbine inlet valve 113 are closed, and the normally closed emergency equalizing valve 118 is opened to mix the combustion gas and the combustion air to equalize the pressure. After the pressure is equalized, the emergency pressure reducing valve 119 is opened to release to the atmosphere.

However, during normal operation, dust in the combustion gas is removed from the high-temperature high-pressure dust removing device 104 and the low-temperature low-pressure dust removing device 13.
8, the dust is released to the atmosphere at a predetermined concentration. However, in the conventional emergency decompression equipment, no dust removal equipment corresponding to the low-temperature and low-pressure dust removal equipment 138 during normal operation is installed in the emergency decompression path. Therefore, dust with a concentration higher than usual is released to the atmosphere in a short time in an emergency. Also, in normal times, the temperature of the combustion gas is reduced by driving the gas turbine, but at the time of emergency depressurization, high-temperature gas is released to the atmosphere because there is no equipment corresponding to the gas turbine. In plants with severe environmental regulations, it is necessary to lower the dust concentration even if the emission time is short and the total emission amount is small. As described above, in the conventional equipment, there is an environmental problem that the dust removal performance in an emergency cannot be made equal to that in a normal operation, and the dust concentration limit value cannot be satisfied in an emergency.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to reduce the temperature of high-temperature flue gas due to differences in the type of coal to be burned, changes in combustion conditions, changes in the particle size distribution of dust, and the like. Prevents a reduction in dust collection efficiency, and allows the dust removal performance to be adjusted without stopping the plant even if the properties of the scattered dust from the furnace fluctuate due to the combustion conditions of the pressurized fluidized-bed boiler. To prevent the generation of dust, etc. from the fallout, and to optimize the fly ash composition in the high-temperature exhaust gas to prevent the abrasion of pipes and cyclones by the dust in the high-temperature exhaust gas, so that it is supplied to the gas turbine. Device and method for a pressurized fluidized-bed boiler capable of effectively reducing the dust concentration in high-temperature exhaust gas, and releasing the air to the atmosphere during an emergency depressurization of the pressurized fluidized-bed boiler To provide a dust removal device for a pressurized fluidized-bed boiler that can reduce the amount of dust in gas to a specified value or less and can prevent fatigue damage to a high-temperature duct wall surface due to excessive thermal deformation and thermal stress during emergency depressurization. is there.

[0011]

The invention claimed in the present application is as follows. (1) A dust removal device that supplies high-temperature exhaust gas discharged from a pressurized fluidized-bed boiler to a cyclone, removes dust in the exhaust gas, and discharges the dust outside the system. A cascade impactor having a measuring device for measurement is provided in parallel with the cyclone, and a flow rate regulator is provided at the cyclone inlet, and the particle size distribution is determined based on the dust particle size distribution in the exhaust gas measured by the measuring device. A dust remover for a pressurized fluidized-bed boiler, wherein the flow rate of exhaust gas entering the cyclone is adjusted by the flow controller so as to fall within the range. (2) A control device according to (1), further comprising a control device for automatically adjusting the flow rate of the exhaust gas entering the cyclone based on the particle size distribution of the high-temperature exhaust gas measured by the measuring device. Dust removal device for pressure fluidized bed boiler.

(3) A means for adjusting the height of the cylindrical portion based on the height of the exhaust gas inlet duct of the cyclone from the floor surface is provided in the cylindrical portion of the exhaust gas outlet of the cyclone. The dust removal device for a pressurized fluidized-bed boiler according to (1) or (2), wherein the dust performance is adjusted.

(4) The pressurized fluidized bed according to any one of (1) to (3), wherein the inner wall of the cyclone is formed of a continuous mesh-like metal having a refractory material held in the mesh. Dust removal device for boiler. (5) The dust removing device for a pressurized fluidized-bed boiler according to (4), wherein an arbitrary area of the continuous mesh-like metal is detachable. (6) The unit mesh of the continuous mesh-like metal piece is polygonal or circular, and the inner peripheral surface on which the refractory material is held has a smooth surface or an uneven surface. (4)
Or the dust removal device for pressurized fluidized-bed boilers according to (5). (7) The dust removing device for a pressurized fluidized-bed boiler according to any one of (4) to (6), wherein a wear-resistant layer is provided on an exposed surface of the continuous mesh-shaped metal. (8) The dust removing device for a pressurized fluidized-bed boiler according to any one of claims 4 to 7, wherein the wear-resistant layer is a hardfacing layer or a thermal spray layer. (9) The coating of the thermal spray layer is made of Al ₂ O ₃ , MgO, Zr
The dust removing device for a pressurized fluidized-bed boiler according to any one of (4) to (8), comprising O ₂ or a mixture thereof.

(10) A method of supplying high-temperature exhaust gas discharged from a pressurized fluidized-bed boiler to a cyclone, removing dust in the exhaust gas, and then discharging the exhausted gas to the outside of the system. Coal as fuel to be supplied to the pressurized fluidized bed boiler so that the filiash component in the exhaust gas satisfies any of the following formulas (1) to (3) based on the measured values. A method for removing dust from a pressurized fluidized-bed boiler, comprising adjusting the supply amount of lime or the addition amount of lime fine particles as a desulfurizing agent. (1) SiO ₂ (chemical analysis value) ≦ 40% by weight (2) SiO ₂ -1.3Al ₂ O ₃ (chemical analysis value) ≦ 15% by weight (3) SiO ₂ -1.3Al ₂ O ₃ -CaO-CaCo ₃ -CaSO ₄ -Fe ₂ O ₃ (chemical analysis value) ≦ −20% by weight (11) The coal fine particles are at least one of fine limestone, fine quicklime and fine slaked lime, and have a particle size of 200 μm or less. The dust removal method for a pressurized fluidized-bed boiler according to (10), wherein:

(12) An emergency dust remover for removing dust from high-temperature exhaust gas discharged at the time of emergency depressurization of the pressurized fluidized bed boiler is provided in any one of (1) to (9). Dust removal device for pressurized fluidized bed boiler. (13) The emergency dust remover includes a spray dust tower that removes high-temperature exhaust gas discharged from the pressurized fluidized bed boiler at the time of emergency depressurization, and a water tank that stores water sprayed to the spray dust tower. The emergency dust remover for a pressurized fluidized bed boiler according to (12), further comprising: (14) The water tank is provided above the spray-type dust tower, and water can be supplied to the spray-type dust tower with a water head difference even immediately after the power is stopped (12).
Or the emergency dust remover for pressurized fluidized-bed boilers according to (13). (15) The pressurized flow according to any one of (12) to (14), wherein a mist separator is provided downstream of the spray-type dedusting tower to discharge dehumidified exhaust gas to the atmosphere. Dust removal device for layer boiler.

(16) A spray pipe is provided in a high-temperature duct for supplying high-temperature exhaust gas to the spray-type dedusting tower, and a shielding plate having a thermal expansion absorbing mechanism is provided inside the high-temperature duct. The dust remover for a pressurized fluidized-bed boiler according to any one of (12) to (15). (17) A slit portion is provided between the shield plates along the exhaust gas flow direction, and an expandable bellow is attached to the slit portion (12) to (16).
A dust remover for a pressurized fluidized-bed boiler according to any one of the above.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view of a dust remover for a pressurized fluidized-bed boiler showing one embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the cyclone of FIG. 1, and FIG. It is sectional drawing. FIGS. 1 to 3 are different from FIG. 21 of the prior art in that a measuring device 24 for measuring the dust particle size distribution in the high-temperature exhaust gas is provided in parallel with the storage containers 15 and 16 containing the cyclones 7 and 8, respectively. The cascade impactor 23 is provided, and a damper 29 is provided as a gas flow controller at the cyclone inlet, and the damper 29 is opened and closed based on the particle size distribution of the high-temperature exhaust gas measured by the measuring device 24. is there. The flue gas discharged from the pressurized fluidized-bed boiler 1 contains about 32 g of dust per m ³ N,
The particle size of the dust is distributed in the range of about 0.1 to 100 μm. The gas temperature is 850-900 ° C.

In FIG. 1, the exhaust gas from the pressurized fluidized-bed boiler 1 is first coarsely dusted by a primary cyclone 7 and finely dusted by a secondary cyclone 8, which poses a problem in blade wear of the gas turbine 10. Not supplied as flue gas. Since there is a pressure loss of the exhaust gas due to the primary cyclone 7 and the secondary cyclone 8 between the hot gas pipe 6 on the inlet side of the primary cyclone 7 and the hot gas pipe 9 on the outlet side of the secondary cyclone 8, the differential pressure of the exhaust gas Has occurred. Therefore, the exhaust gas flows due to the differential pressure of the exhaust gas to the cascade impactor 23 provided in parallel with the primary cyclone 7 and the secondary cyclone 8, and the dust can be collected for each particle size of the dust. The dust collected for each particle size by the cascade impactor 23 is weighed by the measuring device 24, and the particle size distribution can be measured.

2 and 3, the gas flowing from the cyclone inlet pipe 25 descends while rotating in the cyclone body 26 like a gas flow 28, and reversely rises near the dust hopper 27 to rise up. It is discharged from 21. On the other hand, the dust falls along the inner wall of the dust hopper 27 due to the centrifugal force and is discharged as the collected ash 22. In addition, 21 is a cyclone outlet pipe, and 28 is a gas flow. The dust collection efficiency differs due to the difference in the centrifugal force of the gas flow 28 generated in the cyclone main body 26, and the finer the particle size of the dust, the higher the gas flow rate required for dust collection. Therefore, when the particle size of the dust becomes small, the damper 29 at the entrance of the cyclone body 26 is closed,
The dust collection efficiency can be increased by increasing the gas flow rate. The opening and closing of the damper 29 is based on the particle size distribution of dust in the exhaust gas measured by the cascade impactor 23,
Although it is performed so as to be within a predetermined range of the particle size distribution, a control device may be provided to automatically adjust the opening and closing of the damper 29 based on the signal.

For example, when the particle size of the dust becomes large, the wear of the castable inside the cyclone is prevented by reducing the gas flow rate of the exhaust gas by opening the damper 29 in the opening direction, and when the particle size of the dust becomes small, By increasing the gas flow velocity by setting 29 to the closing direction, it is possible to prevent the dust collection efficiency from lowering and prevent the blades of the gas turbine 10 from being worn. In this way, a damper for adjusting the gas flow rate is provided at the inlet of the cyclone, and the control damper for the cyclone inlet is opened and closed based on the particle size distribution of the dust measured by the cascade impactor to adjust the gas flow rate at the cyclone inlet. By setting the gas flow rate suitable for the particle size distribution of the dust, it is possible to prevent a reduction in dust collection efficiency caused by a change in the particle size distribution of the dust due to a change in the type of coal to be burned and a change in the combustion state. Of the blade can be effectively prevented.

FIG. 4 is an explanatory view of a cyclone container used in a dust remover showing another embodiment of the present invention. In FIG. 4, the cyclone inner cylinder 37 of the cyclone element 32 stored in the cyclone container 33 is provided with an inner cylinder slide mechanism 34 that slides the inner cylinder 37 in the vertical direction, and is supplied to the cyclone element 32. The depth of insertion of the cyclone inner cylinder 37 from the floor of the inlet duct can be adjusted according to the nature of the dust in the exhaust gas. The dust-containing exhaust gas flows in from the container account 30. The inflowing gas is distributed into and flows into the individual cyclone elements 32, descends while swirling in the cyclone, reversely rises near the leg 36, passes through the cyclone inner cylinder 37, and is mixed with gas from other elements in the outlet plenum 37. ,
It is discharged from the container account 31. The dust in the exhaust gas moves to the wall side by the air flow swirl in the cyclone, reaches the wall surface, and the collected dust descends along the wall surface, gathers in the container hopper from the leg 36, and goes out from the ash discharge seat 35 to the outside. Is discharged. When the properties such as the particle diameter or dust concentration of the furnace scattered dust fluctuate during the operation of the plant, by adjusting the insertion depth of the inner cylinder 37 by the inner cylinder slide mechanism 34,
Without stopping the plant, adjustments can be made to obtain optimum dust removal efficiency for inlet dust conditions.

That is, the dust-containing exhaust gas is introduced below the floor of the duct provided at the entrance of the cyclone element 32. If the insertion depth of the inner cylinder is insufficient, a part of the dust Is immediately short-passed to the inner cylinder side and is not collected, so that a phenomenon that the overall dust removal efficiency is reduced may occur. If the inner cylinder is inserted too deeply, only the pressure loss of the cyclone increases, but the dust removal efficiency reaches a peak and the power generation efficiency of the entire plant decreases. The effect of the insertion depth of such a cyclone inner cylinder on the dust removal efficiency was examined using the cyclone shown in FIG. 5, and the results are shown in FIG. The ratio of the inner cylinder insertion depth h to the inlet duct height B (inner cylinder length ratio) is 0.04 to
The experiment was carried out with the range of 0.22, but it is effective to change the insertion depth of the inner cylinder of the cyclone to adjust the dust removal efficiency of the cyclone. In particular, h / B = 0.1
It was found that the highest dust removal efficiency was obtained when the value was 2. FIG. 7 shows a cyclone container in which the inner cylinder slide mechanism 34 is provided in the cyclone container hopper so that the insertion depth of the inner cylinder 37 can be adjusted. In this case, the same effect as described above can be obtained. Can be

FIG. 8 is an explanatory sectional view of a cyclone used in a dust remover showing another embodiment of the present invention.
FIG. 10 is an enlarged sectional view of the portion A in FIG. 8, and FIG. 10 is an explanatory view taken along the line BB 'in FIG. 8 and 9, the cyclone main body 41 having a height of about 20 m is attached to the cyclone outer surface 5.
0, a refractory material 44, and a continuous mesh-like metal member 45. The feet of the continuous mesh wire mesh anchor 45 are fixed to the casing 43 at the welded portions 52, and the refractory material 44 is held by the continuous mesh metal anchor 45 to prevent peeling and falling off. The material used for the metal mesh is not particularly limited because it varies depending on the use temperature.
In the case of a cyclone for a pressurized fluidized-bed boiler at 900 ° C., SUS310 (25Cr20Ni-F) which is heat-resistant steel is used.
e) or SUS304 (18Cr8Ni) can be suitably used. The method of fixing by welding is not particularly limited, and can be arbitrarily selected depending on the shape and material of the mesh-like metal and the construction thickness and material of the refractory to be constructed. The mesh shape of the mesh metal is not particularly limited.
(A) to (d), such as a polygon such as a square or a hexagon, or a circle.

The cyclone main body 41 is required to have abrasion resistance because the exhaust gas containing high-temperature, high-speed and high-concentration ash collides with the cyclone body 41, and a refractory is installed on the inner surface thereof. The material is weak to thermal shock, especially the refractory applied to the inner surface of the cyclone body is 600 ℃
/ h or more rapidly heating and cooling at a heating / cooling rate of at least, there is a risk of peeling and falling off of the refractory material due to thermal shock, but in the present invention, the refractory material installed on the inner wall of the cyclone body as described above Is held in a continuous mesh metal mesh, and since the surface of the refractory material is covered with the continuous mesh metal, the refractory material can be prevented from peeling and falling off due to thermal shock.

When a high-temperature combustion gas (800 to 900 ° C.) having an ash concentration of several 10 g / Nm ³ collides at a flow rate of several tens m / s, the exposed surface of the reticulated metal holding the refractory material is earlier than the refractory material. If there is a risk that the refractory material will be peeled off or fall off due to abrasion or damage, the exposed surface of the reticulated metal anchor 45 is subjected to abrasion treatment as shown in FIG.
By providing the same, it is possible to obtain abrasion resistance equal to or higher than that of the refractory material, and thereby it is possible to prevent the refractory material from peeling off and falling off due to continuous damage to the reticulated metal. Examples of the wear-resistant layer include a hardfacing layer formed by a build-up welding method or a sprayed layer formed by explosive spraying, plasma spraying, or the like. Alternatively, these layers may be formed on the surface of the metal mesh in advance, and then the refractory material may be covered. Al ₂ O ₃ , Mg
A film made of O, ZrO ₂ or a mixture thereof is preferable because it has a thermal expansion coefficient equal to or close to the thermal expansion coefficient of the network metal. Specifically, since the mesh metal has a thermal expansion coefficient of 11 to 13 × 10 ⁻⁶ / ° C., it is a material having a thermal expansion coefficient of 8.0 × 10 ⁻⁶ / ° C. or more close thereto. preferable. In short, it is preferable to cover the surface of the refractory material with a mesh-like metal having a wear resistance equal to or higher than that of the refractory material.

Even if the refractory material and the reticulated metal covering the same are simultaneously damaged and the refractory peels or falls off locally, the refractory material can be detached at any position. The repair of the mesh-shaped metal can be easily performed after the partial repair. As such a mesh-shaped wire mesh structure, a structure shown in FIG. In FIG. 10 (b), a continuous mesh-like metal anchor 45 is composed of a combination of a plurality of hexagonal mesh-type metal anchors of one unit, adjacent mesh hardware is fixed with the anchor claws 19, and an arbitrary region is removed. It is made detachable by means of. Also, as shown in FIGS. 10 (c) and 10 (d), the inner peripheral surface of one unit of mesh metal may be of a smooth type or may have a structure having irregularities. In this case, the effect of preventing the refractory material 44 from falling off is improved by the projections 56 on the inner peripheral surface of the mesh-shaped metal. The material of the refractory material is not particularly limited, and is generally applicable to a refractory material having wear resistance. In addition, as the construction method,
Coating, driving, and trowel coating methods can be adopted, and there is no particular limitation. Further, by performing the construction so that the surface of the continuous reticulated metal and the surface of the refractory material are flush with each other, the effect of preventing the refractory material from peeling and falling off is further improved.

FIG. 12 is an explanatory view of a dust remover for a pressurized fluidized-bed boiler showing still another embodiment of the present invention. As fuel for pressurized fluidized bed boiler (PFBC), there is a method in which coal is supplied in a dry state and a method in which CWP (Coal Water Paste) is used.
) Is known, but here C
The case where the WP method is used will be described. In FIG. 12, raw coal as fuel for PFBC is a raw coal bunker 61.
Is sent to a coarse pulverizer 62 and coarsely pulverized to a particle size of about 2 to 3 mm. The reason why the coarsely pulverized coal having a diameter of 2 to 3 mm is used as a fuel is that it is necessary to stay in the bed for a sufficient time in order to perform combustion sufficiently. However, if the CWP is composed only of the coarse coal, troubles such as blockage in the pipes are likely to be caused. Therefore, the fine coal pulverized by the fine pulverizer 63 and the above coarse coal are kneaded by the kneader 64. At this time, limestone as a desulfurizing agent is simultaneously supplied from the coarse limestone tank 65 and kneaded. Limestone is supplied in coarse particles (typically 1 to 3 mm) because a sufficient residence time is required to cause a desulfurization reaction in the bed. The fuel kneaded in this way is temporarily stored in the CWP tank 66, and the CWP pump 6
It is sent into the fluidized bed at 7.

The fuel burns in the fluidized bed and has a particle size capable of being scattered. The desulfurizing agent CaCO ₃ (including CaO partially generated by the decarboxylation reaction) and the desulfurization reaction product Ca
The SO ₄ becomes fly ash and passes through the high-temperature gas pipe 68 together with the exhaust gas, and the cyclone 69 and the high-precision dust removing device 70
(Ceramic filter or high-precision cyclone), and then to the gas turbine. At this time, the wear of the high-temperature gas pipe, the cyclone, and the gas turbine becomes a problem. However, since the amount of wear increases with time, the fly ash composition is periodically sampled by the fly ash sampling device 72 and analyzed by the analysis device 73. By examining the above, it is possible to deal with the wear phenomenon. Hereinafter, the relationship between the fly ash composition and the wear phenomenon will be described in detail.

Table 1 shows the chemical composition of fly ash and the results of abrasion tests. In a small pilot plant, various types of coal were burned, fly ash was collected, and fly ash impact wear experiments were conducted at high temperatures. It is the result of having performed. In Table 1, fly ash G, H, and I are fly ash obtained from a small pilot plant to which fine-grained quartz (average particle size is about 40 microns) is added, and fly ash J is pure fine-grained quartz. From Table 1, it can be confirmed that, depending on the type of the lime, the wear phenomena occurs, or the ash is divided into two forms, in which the wear does not occur and the fly ash adheres.

[0030]

[Table 1]

This phenomenon is considered to be related to the composition of fly ash, and (1) the distinction between fly ash composition and wear and adhesion, and (2) the relationship between fly ash composition and wear rate are summarized and FIG. ), (B) and (c). That is, (a) in FIG.
Regarding the relationship between O ₂ and the wear rate, (b) shows that quartz, which is the main mineral that causes wear, has SiO ₂ − as a chemical analysis value.
1.3 Considering that it can be approximated by Al ₂ O ₃ (Reference: EPRICS-5071 Report 2711-1 Final Report Fe
b. 1987 "Fire Side Corrosion and Fly Ash Erosion i
n Boiler "), those arranged by values of SiO ₂ -1.3Al ₂ O ₃ , and (c)
CaO as a component, as CaCO _3, CaSO ₄ and Fe ₂ O ₃ suppresses wear because softer composition than the metal at that temperature, the quartz corresponding amount (SiO ₂ -1.3
Al ₂ O ₃ ) minus this component, specifically SiO ₂ -1.3 Al ₂ O ₃ -CaO, CaCO ₃ , C
aSO ₄ —Fe ₂ O ₃ .

FIG. 13 shows that there is a limit parameter value that governs the wear and adhesion phenomena regardless of which method is used, and the wear and adhesion phenomena can be clearly determined by using the parameter values, and the wear rate can be somewhat increased. It became clear that they also corresponded. This means that abrasion of PFBC exhaust gas equipment can be prevented by appropriately controlling the composition of fly ash. The composition of this fly ash is derived from the ash component in the coal and the Ca component added as a desulfurizing agent, and the controllable desulfurizing agent component (Ca component) is also included as a factor as shown in FIG. 13 (c). We paid attention to that. 13 (a) and 13 (b)
Is simply arranged by SiO ₂ and SiO ₂ -1.3Al ₂ O _3. However, if the desulfurizing agent component is increased, the values of both are reduced, so that it is possible to set the component range so as not to wear.

Next, a means for adding a Ca component in order to control the composition in fly ash within a range not causing wear will be described below. First, as to what kind of chemical composition is suitable as the Ca component, CaCO ₃ , CaO, Ca (O
H) ₂ is suitably added. Next, as a place where the Ca component is added, there are two methods that can be considered to be a hot gas pipe inlet (furnace outlet) and a furnace gas. However, since it is more effective to contribute to the desulfurization reaction, it is better to put in the furnace. It is. When adding to the furnace,
It is appropriate that the particle size is smaller than the particle size of fly ash. In the case of CaCO ₃ , the particle size scattered at a superficial velocity of 1.0 m / s, a pressure of 8.5 atg, and a temperature of 850 ° C. is about 0.
2 mm. Such a maximum particle size can be generally determined from a flow velocity (terminal velocity) at which the gravity acting on the particles and the buoyancy received from the fluid are balanced.

The abrasion phenomenon is a phenomenon in which quartz, which is harder and more angular than metal, collides with the metal and causes tears, which are cumulatively reduced in thickness. On the other hand, CaO, CaCO ₃ Since Ca components such as CaSO ₄ are softer than metals, they do not have an abrasion effect, but rather deposit thinly on the surface. FIG. 14 is a model diagram showing a mechanism of a phenomenon in which abrasion or adhesion occurs depending on the amount of SiO ₂ . FIG. 14A is a model diagram in the case where the amount of SiO ₂ is small relative to the Ca compound. However, since the proportion of the Ca compound 77 is large, the Ca compound 77 adheres to the metal 75 to form a thin film 76. Since the temperature is as high as 850 ° C., slight sintering also occurs, and the film thickness δ increases. Accordingly, quartz (SiO ₂ ) 78 collides from above the formed film, but collision damage does not reach the base metal 75. on the other hand,
As shown in (b), when the proportion of the Ca compound decreases, the film thickness δ decreases, and the collision damage of the quartz 78 reaches the metal 75, and it is considered that the wear proceeds. In this way, it is considered that there is a limit value at which a change from abrasion to adhesion occurs.

Next, the amount of CaCO ₃ actually supplied will be described. The most wearable fly ash collected from the PFBC small pilot plant has 44% SiO ₂ ,
In order to obtain fly ash with no abrasion, the amount of SiO ₂ needs to be 40% or less as described above. The amount of fine CaCO ₃ supplied for this purpose is 2.3% based on the supplied coal amount, based on the following assumptions. (1) In order to make SiO ₂ from 44% to 40%, Si
Fine CaCO ₃ may be added at a ratio of 10 to O ₂ , that is, at a ratio of 23% to SiO ₂ . (2) SiO ₂ is all derived from coal ash.
In the case of coal, ash is present in the coal at 15%. (3) 65% of SiO ₂ is present in the ash.

The amount of CaCO ₃ supplied as a desulfurizing agent is about 10% based on coal. (S content is 0.6-1%
It is possible to control the composition to the limit without wear by repeating the analysis of the composition after mixing the fine-grained limestone tank several times, assuming that Ca / S = 3 to 4 is supplied. is there. The timing of fly ash analysis is as follows: (a) when the coal used changes (since the ash content and SiO ₂ amount changes); and (b) when the desulfurizing agent changes (the weathering rate of the desulfurizing agent decreases. It will be different),
(c) When the load is changed (because the bed height changes, the weathering rate of the desulfurizing agent changes), etc. Although an example in which fine limestone is mixed into CWP has been described above, fine limestone can be supplied into a furnace in a dry manner using a rock hopper. As the Ca component to be mixed, CaO or Ca (OH) ₂ can be used in addition to CaCO ₃ .

As the sample analyzer 73, Si,
As long as it can analyze Ca, Al, Fe, and CO ₃ roots and SO ₄ roots, plasma emission spectroscopy (ICP) is required to analyze Si, Ca, Al, Fe in a relatively short time with high accuracy. Is preferred. A known titration method can be employed as a method for analyzing CO ₃ roots and SO ₄ . SiO ₂ -1.3Al ₂ O ₃ —CaO—CaCO calculated from analysis results
_When the value of _3- CaSO ₄ —Fe ₂ O ₃ becomes -20% or more, fine limestone is mixed into the kneader 4 from the fine limestone tank 71 to increase the Ca component in fly ash. The composition control index is S as described above.
The value of iO ₂ itself, or SiO ₂ -1.3Al ₂
The value of O ₃ may be used.

FIG. 15 is an explanatory view of an emergency dust removing apparatus for a pressurized fluidized-bed boiler, showing still another embodiment of the present invention. In FIG. 15, the difference from FIG. 21, which is a conventional technique, is that a silencer 121, an emergency dust removal tower 122 and a mist separator 123 are provided downstream of the emergency pressure reducing valve 119, and a boiler trip, emergency stop such as when all power supply in the station is stopped, Emergency A immediately after
The point is that the gas released at the time of decompression can be dedusted and cooled even without the C power supply. In FIG. 15, in an emergency such as a boiler trip, it is necessary to isolate the compressor 112 and the gas turbine 113 and decompress the entire system. That is, immediately after the trip, the compressor outlet valve 111 and the gas turbine inlet valve 110 are closed, and the normally closed emergency equalizing valve 118 is opened to mix and equalize the combustion gas and the combustion air. By opening the emergency pressure reducing valve 119 after equalizing the pressure, the mixed gas is guided to the emergency dust removal tower 122 via the silencer 121. The gas removed in the emergency dust removal tower 122 is released to the atmosphere after being dehumidified in the mist separator 123.

FIG. 16 is an explanatory view of the emergency dust removing device.
This emergency dust removal device includes a spray water circulation system having a dust removal tower spray water upper tank 126 capable of supplying spray water, and an emergency dust removal tower 122. In FIG. 16, a mixed gas 125 of high-temperature combustion gas and air released at the time of emergency decompression enters the emergency decompression pipe 120 from the upper part, and
After being cooled and dedusted by passing through the spray water inside the emergency dedusting tower 120, the emergency dedusting tower outlet duct 1
Released to 24. After the moisture contained in the gas is removed by the mist separator 123, it is released to the atmosphere. The spray water 138 for dedusting and cooling the mixed gas is stored in the dedusting tower spray water upper tank 126 in consideration of the time when the entire power supply in the station is stopped, and until the emergency AC power becomes available in an emergency. The upper tank outlet valve 1 for a few minutes
27 is opened and sprayed into the emergency dust removal tower 122 due to the head difference between the dust tower upper tank 126 and the dust tower spray 129.

The spray water 138 descending in the dust tower and absorbing the dust in the mixed gas 125 is used to supply cooling water from the lower part of the dust tower through the dust tower outlet pipe 130 while the emergency AC power supply is stopped. It accumulates in the dedusting tower lower tank 131 having a capacity equal to or larger than the amount that can be held. When the emergency AC power becomes available, it is supplied to the dust removal tower upper tank 126 by the spray water circulation pump 132 and sprayed into the dust removal tower again. The spray water 138 circulates and de-dusts and cools the released gas mixture 125 while the entire system is depressurized. Part of the spray water 138 is mixed gas 12
The spray water 138 is replenished from the makeup water supply pipe 136 in order to replenish the reduced amount of spray water because it is heated and evaporated by 5 and flows out of the emergency dust removal tower 120 together with the mixed gas 125. After the emergency depressurization, the spray water 138 containing dust opens the spray water drain valve 134 and is drained from the spray water drain pipe 135 to the outside of the system.

As described above, by providing the emergency dust removal tower and the spray water circulation system and holding the spray water in the upper tank installed above the emergency dust removal tower, the emergency AC power supply can be started earlier than in an emergency. Since the spray water can be supplied to the emergency dust tower by the difference in water head, the spray water can be sprayed into the dust tower immediately before the mixed gas at the time of emergency depressurization flows into the emergency dust tower. The spray water sprayed into the tower removes dust in the mixed gas and cools the high-temperature mixed gas.

FIG. 17 is an explanatory view of an emergency dust remover for a pressurized fluidized-bed boiler, showing still another embodiment of the present invention. 17 differs from FIG. 15 in that the cooling water stored in the water tank 126 is also sprayed into the emergency decompression pipe (high-temperature duct) 120 by the spray pipe 202 and the spray nozzle 203.
And the same effect as in FIG. 15 can be obtained.

In FIG. 17, high-temperature exhaust gas (mixed gas)
Since the 125 is cooled by the latent heat of evaporation of the sprayed whistle, it is general to estimate the unevaporated amount and supply a little more spray than the required amount. In a high-temperature duct having such a spray-type exhaust gas cooling mechanism, a wet portion formed by spray droplets arriving and colliding without evaporating, and a drying portion in which high-temperature gas comes in contact directly without spray droplets being generated,
These regions are usually unevenly distributed in the hot duct due to the eccentricity of the gas and spray jets and their inadequate mixing, causing thermal deformation due to large temperature differences between the sites Therefore, the non-uniform temperature distribution generated in the high-temperature duct generates irregular thermal deformation and large thermal stress, and the duct is fatigued and damaged by the repetition. No consideration is given to the absorption mechanism, and damage to the hot duct and associated gas leakage are foreseen.

Although the duct casing and the duct reinforcing material are insulated from the internal fluid and are structurally improved without temperature distribution, it is necessary to apply a heat insulating material that can withstand repeated drying and wet by spray water. In addition, it is indispensable to dispose a heat-insulating material protective cover plate using a heat-resistant steel material suitable for abrasion by the spray jet on the inner surface side, which results in an uneconomical structure. Even in this case, a non-uniform temperature distribution is generated between the wet and dry surfaces in the cover plate, the plate is deformed, and a new structural problem such as abrasion of the heat insulating material due to a gas flow from the gap occurs. In addition, since the casing and the external reinforcing material are connected at a fixed point such that the circumferential elongation of the casing is not restricted, a constant temperature distribution in the duct circumferential direction and the difference in elongation between the casing and the reinforcing material are fixed points. By properly designing the arrangement of the corners and the corner curvature with respect to the elongation, the above problem can be caused by the non-uniform temperature distribution and the temperature distribution in the flow direction.

FIG. 18 is a structural explanatory view of a duct casing provided with a shielding plate with a telescopic function capable of solving the above-mentioned problem, and FIG. 19 is a bellows mounting of a telescopic mechanism for absorbing the elongation of the casing. A detailed sectional view is shown. In FIGS. 18 and 19, a plurality of spray pipes 202 for cooling the inflowing high-temperature gas are installed in a duct casing 201 constituting the peripheral wall of the high-temperature gas duct 217 so as to penetrate through the duct casing 201. 202 also has a structure that can move on the distal end side in consideration of the thermal expansion difference between the duct casing 201 and the spray pipe 202.

The shield plate 205 is provided inside the high-temperature duct 217.
However, as shown in FIG.
Installed with. The shielding plate 205 is divided in the circumferential direction and the longitudinal direction. Each of the shielding plate pieces has an elliptical hole 218 having a margin for the amount of thermal deformation except for one fixed point, and a washer and a bolt / bolt. They are connected by a nut 208 and integrated. This structure can be realized by using the shielding plate 205 as a partition plate that does not receive a pressure load. With this structure, the rapid temperature distribution arbitrarily generated in the shielding plate 205 can also minimize plastic deformation and damage due to heat by moving small pieces of the individual shielding plates 205 freely. However, even with this structure, the growth and wear of the deformation of the shielding plate 205 cannot be avoided, but any combination can be efficiently repaired by using a combination structure of small pieces that can be disassembled. The fixing portion to the support 6 has an elliptical hole 218 in the extending direction.
Is provided, and this portion is also free from thermal displacement. Further, it is preferable that the installation range of the shielding plate 205 be from a position higher than the spray position to the vicinity of the position where the cooling of the gas is completed.

As shown in FIG. 19, the duct casing 1 spans the mounting range of the shield
The hat-shaped bellows 210 is attached so as to cover the slit 215. There is no particular limitation on the shape of the bellows 210 used in the expansion and contraction mechanism as long as the expansion and contraction is easy. In this structure,
Around the casing 201, the duct reinforcing material 21 is provided at regular intervals.
1 is provided to restrain the deflection of the casing due to the internal pressure of the duct and maintain the pressure. Also in this reinforcing structure, the reinforcing member is of a back stay type attached to the casing with the clip 212 so that the duct casing can be deformed at the slit 215 in the circumferential direction and can absorb heat regardless of the reinforcing member. According to this structure, the duct casing of the gas cooling section does not come into contact with the high-temperature gas and the cooling spray water, and is released from excessive thermal deformation and thermal stress. Further, even with respect to the secondary temperature distribution in the flow direction due to the installation of the shielding plate, the elongation is absorbed by the bellows in the elongation absorbing mechanism added to the casing, so that there is no problem. On the other hand, the shield plate is also basically a bolted joint having an elongation allowance for attachment and joining, which solves the problems of the conventional structure in terms of deformation and stress.

As described above, the cylindrical shielding plate is provided inside the duct from the upstream side of the cooling spray portion to the downstream side of the distance where the gas is sufficiently cooled, and the introduced gas is formed by the shielding plate. Cooling water is sprayed only inside this inside, and the above-mentioned complicated temperature distribution is inevitable on the shielding plate.However, the structure has a structure that allows free thermal expansion in the circumferential and flow directions. It is preferable to make it function only as a plate, and to have a structure in which the shielding plate is divided into small plates, and each of the plates is formed by bolting with an allowance so that each plate can freely expand in a plane. . In addition, due to the installation of the shielding plate, the duct casing near this area has a sudden temperature gradient due to the presence or absence of gas flow at the mounting portion (starting point) of the shielding plate, and the casing is dried and wet due to residual spray droplets at the end point of the shielding plate. To prevent a sudden temperature distribution from occurring due to the difference, a slit (gap) is provided in the duct casing in the flow direction to absorb the thermal expansion difference in the circumferential direction. (Bellow)
It is preferable that the expansion mechanism is installed over the entire length of the shield plate mounting area where a sudden temperature change is expected.

The hot gas that has flowed in does not come into contact with the duct casing until it passes through the shield plate after the shield plate, and in the area where the shield plate is installed, the casing is isolated from the spray droplets. The casing of the strength member, which holds the internal pressure, is relieved from uneven and severe temperature changes. Further, since the temperature gradient generated at the entrance and exit of the shielding plate due to the installation of the shielding plate is absorbed by the above-described expansion and contraction mechanism incorporated in the casing, the distance between the casing heated by the high-temperature gas and the cooled casing ( By properly taking the length of the shielding plate, the temperature gradient inside the casing can be adjusted,
Large thermal stresses can be avoided. On the other hand, a large temperature difference occurs before and after spraying and between the wet and dry surfaces on the inner shield plate, but this shield plate is also made of steel plate with a structure in which small pieces are assembled by free-stretching bolt joints. Deformation can be prevented. In addition, since there is no constraint on thermal expansion in whole or small pieces, thermal stress is also small in a single piece plate. 4 and 2 described above.
The apparatus, structure, etc. shown in FIG. 0 are individually applicable to a pressurized fluidized-bed boiler combined cycle power plant.

[0050]

According to the dust removing apparatus and method for a pressurized fluidized bed boiler of the present invention, the dust concentration in the high temperature exhaust gas discharged from the pressurized fluidized bed boiler can be effectively reduced, and It can prevent blade wear and the like, and has the following excellent effects. (1) It is possible to prevent a reduction in dust collection efficiency due to a difference in burning coal type, a change in combustion state, a change in dust particle size distribution, and the like, and to prevent wear of a gas turbine blade. (2) If the properties of the furnace scattered dust fluctuate during plant operation, without stopping the plant, the dust properties can be adjusted by adjusting the inner cylinder slide mechanism from outside the cyclone containment vessel to adjust the inner cylinder insertion depth. It is possible to provide a dust removing device which can obtain an optimum dust removing efficiency corresponding to the above. (3) The reliability is greatly improved because a great effect can be exerted to prevent the peeling and falling off of the refractory wall lining the cyclone during operation or at the start and stop.

(4) By optimizing the fly ash composition of the exhaust gas discharged from the pressurized fluidized bed boiler, the PF
Wear of the high-temperature gas pipes, cyclones and gas turbine blades of the BC plant can be prevented, and stable operation is possible. Further, since the flow velocity can be increased, the heat loss of the high-temperature gas pipe is reduced, and the gas turbine efficiency can be increased. In the cyclone, since the flow velocity can be increased, dust can be removed with high efficiency. (5) In a pressurized fluidized-bed boiler, it is necessary to reduce the pressure in the air system, boiler and flue gas system in order to protect the equipment in the event of an emergency such as a boiler trip. It can be cooled while removing dust. (6) In a duct having a spray-type gas cooling mechanism,
An economical duct that is small in deformation and stable in structural strength can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a dust remover for a pressurized fluidized-bed boiler showing one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the cyclone of FIG.

FIG. 3 is a cross-sectional view of the cyclone of FIG.

FIG. 4 is an explanatory view of a dust remover for a pressurized fluidized-bed boiler showing another embodiment of the present invention.

FIG. 5 is a diagram showing the effect of the cyclone inner cylinder of FIG. 4 on the insertion depth and the dust removal efficiency.

FIG. 6 is a view showing the effect of the cyclone inner cylinder of FIG. 4 on the insertion depth and the dust removal efficiency.

FIG. 7 is an explanatory view of a dust remover for a pressurized fluidized-bed boiler showing another embodiment of the present invention.

FIG. 8 is an explanatory view of a dust remover for a pressurized fluidized-bed boiler showing another embodiment of the present invention.

FIG. 9 is an enlarged sectional view of A in FIG. 8;

FIG. 10 is an explanatory sectional view taken along the line BB ′ of FIG. 9;

FIG. 11 is an explanatory view in which an abrasion-resistant layer is provided on an upper part of a mesh-like metal member.

FIG. 12 is an explanatory view of a dust remover for a pressurized fluidized-bed boiler showing another embodiment of the present invention.

FIG. 13 is a graph showing the relationship between fly ash composition and wear rate.

FIG. 14 is a diagram showing the progress of wear due to fly ash components.

FIG. 15 is an explanatory view of a dust remover for a pressurized fluidized-bed boiler showing another embodiment of the present invention.

FIG. 16 is an explanatory view of an emergency dust removing device.

FIG. 17 is an explanatory view of an emergency dust removing device.

FIG. 18 is a partial cross-sectional explanatory view of a high-temperature duct having a shielding plate with a telescopic function.

FIG. 19 is a partial cross-sectional explanatory view of a high-temperature duct having a shielding plate with a telescopic function.

FIG. 20 is a partial cross-sectional explanatory view of a high-temperature duct having a shielding plate with a telescopic function.

FIG. 21 is an explanatory view of a dust removing device for a pressurized fluidized-bed boiler according to a conventional technique.

FIG. 22 is an explanatory view of a conventional cyclone.

FIG. 23 is an explanatory view of a wear-resistant structure of a cyclone inner wall according to a conventional technique.

FIG. 24 is an explanatory view of a conventional emergency dust removal device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pressurized fluidized bed boiler, 2 ... Steam turbine, 6 ... High temperature gas piping, 7 ... Primary cyclone, 8 ... Secondary cyclone, 9
... Cow gas piping, 10 ... Gas turn, 13 Low temperature dust collector, 23 ... Cascade impactor, 24 ... Measuring instrument, 2
6: cyclone body, 27: dust hopper, 29: damper, 32: cyclone element, 33: cyclone container, 34: inner cylinder slide mechanism, 37: cyclone inner cylinder,
41: cyclone body, 43: casing, 44: refractory material, 45 mesh metal anchor, 53: anchor pawl, 54:
Abrasion resistant layer, 56: protrusion, 64: kneader, 71: fine limestone tank, 72: fly ash sampling device,
73 ... Fly ash analyzer, 74 ... Control valve, 122 ... Emergency dust remover, 123 ... Mist separator, 126 ... Dust tower spray water upper tank, 201 ... Duct casing, 202 ... Spray piping, 205 ... Shield plate, 210 ... Bellows, 215 ... Slits, 218 ... Oval holes,

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kyoichi Murakami, Inventor Kyoichi 3-36, Takaracho, Kure-shi, Hiroshima Prefecture Inside the Kure Research Laboratory (72) Inventor Yuji Fukuda 3-36, Takaracho, Kure-shi, Hiroshima Prefecture, Babcock Hitachi, Ltd. Inside the Kure Research Laboratory (72) Inventor Masaharu Kuramoto 6-9 Takaracho, Kure City, Hiroshima Prefecture Inside the Babcock Hitachi Kure Factory (72) Inventor Shinichi Oshita 6-9 Takaramachi, Kure City, Hiroshima Prefecture Inside the Babcock Hitachi Kure Factory (72) Inventor Takayuki Ishida 6-9 Takara-cho, Kure-shi, Hiroshima Pref. Inside the Kure Factory, Babcock Hitachi Co., Ltd. (72) Tomohiko Miyamoto 7-1-1, Omika-cho, Hitachi-shi, Ibaraki Pref. Hitachi Research Laboratory, Ltd. (72) Inventor Hiroshi Hashimoto 6-9, Takara-cho, Kure City, Hiroshima Prefecture Inside the Babcock Hitachi Kure Plant (72) Inventor Haru Arakawa 6-9 Takara-cho, Kure City, Hiroshima Prefecture Inside the Babcock Hitachi Kure Factory (72) Inventor Hideo Happiness 6-9 Takaracho Kure City, Hiroshima Prefecture Inside the Kure Factory Babcock Hitachi (72) Inventor Toru Nishioka Kure City, Hiroshima Prefecture 6-9 Takaracho, inside the Kure Factory, Babcock Hitachi Co., Ltd. (72) Inventor Ryuji Kurashichi 3-36 Takaracho, Kure City, Hiroshima Prefecture Inside the Babcock Hitachi, Ltd. Kure Research Institute (72) Genroku Nakao 3, Takaracho, Kure City, Hiroshima Prefecture No. 36 Babcock Hitachi Kure Research Institute (72) Inventor Tokuyuki Ichinose 6-9 Takaracho, Kure City, Hiroshima Prefecture Babcock Hitachi Kure Factory (72) Inventor Shuhei Akimoto 6-9 Takaracho Kure City, Hiroshima Prefecture Babcock Inside the Kure factory, Hitachi, Ltd. (72) Inventor Shigenobu Oshima 6-9 Takaracho, Kure-shi, Hiroshima Prefecture Inside the Kure factory, Babcock Hitachi Co., Ltd. (72) Inventor Shigeru Nozawa 6-9 Takaracho, Kure-shi, Hiroshima prefecture Babcock Hitachi, Ltd. F-term in the factory (reference) 3K064 AA04 AA06 AA10 AA17 AB01 AC01 AC05 AC11 AD01 AD05 AF03 BA19 BA24 BB03

Claims (17)

[Claims] 1. A dust removal device for supplying high-temperature exhaust gas discharged from a pressurized fluidized-bed boiler to a cyclone, removing dust in the exhaust gas, and discharging the dust to the outside of the system, wherein the particle size of the dust in the high-temperature exhaust gas is reduced. A cascade impactor equipped with a measuring device for measuring the distribution is provided in parallel with the cyclone, and a flow controller is provided at the cyclone inlet, and the particle size distribution is determined based on the dust particle size distribution in the exhaust gas measured by the measuring device. Wherein the flow rate of exhaust gas entering the cyclone is adjusted by the flow controller so that the flow rate falls within a predetermined range. 2. The apparatus according to claim 1, further comprising a control device for automatically adjusting a flow rate of the exhaust gas entering the cyclone based on a dust particle size distribution in the high-temperature exhaust gas measured by the measuring device. Dust removal device for pressurized fluidized bed boiler. 3. A means for adjusting the height of the cylindrical portion on the basis of the height of the exhaust gas inlet duct of the cyclone from the floor surface is provided in the cylindrical portion of the exhaust gas outlet of the cyclone, The dust removing device for a pressurized fluidized-bed boiler according to claim 1 or 2, wherein the performance is adjusted. 4. The pressurized fluidized-bed boiler boiler according to claim 1, wherein the inner wall of the cyclone is formed of a continuous mesh-like metal having a refractory material held therein. Dust equipment. 5. The dedusting device for a pressurized fluidized-bed boiler according to claim 4, wherein an arbitrary region of the continuous mesh-like metal is detachable. 6. The unit mesh of the continuous mesh-like metal piece has a polygonal or circular shape, and the inner peripheral surface on which the refractory material is held has a smooth surface or an uneven surface. The dust removing device for a pressurized fluidized-bed boiler according to 4 or 5. 7. The dust removing apparatus for a pressurized fluidized-bed boiler according to claim 4, wherein an abrasion-resistant layer is provided on an exposed surface of the continuous mesh-shaped metal. 8. The dust removing device for a pressurized fluidized bed boiler according to claim 4, wherein the wear-resistant layer is a hardfacing layer or a thermal spray layer. 9. The coating of the thermal spraying layer is made of Al ₂ O ₃ , Mg
O, ZrO ₂ or pressurized Doso dedusting apparatus boiler according to any one of claims 4-8, characterized in that it consists of a mixture thereof. 10. A method of supplying a high-temperature exhaust gas discharged from a pressurized fluidized-bed boiler to a cyclone, removing dust in the exhaust gas, and discharging the exhaust gas out of the system, wherein fly ash components in the exhaust gas entering the cyclone Is measured, and based on the measured value, the filly ash component in the exhaust gas has the following formula:
In order to satisfy any of (1) to (3), the amount of coal supplied as fuel to the pressurized fluidized bed boiler or the amount of lime fine particles added as desulfurizing agent is adjusted. Dust removal method for pressurized fluidized bed boiler. (1) SiO ₂ (chemical analysis value) ≦ 40% by weight (2) SiO ₂ -1.3Al ₂ O ₃ (chemical analysis value) ≦ 15% by weight (3) SiO ₂ -1.3Al ₂ O ₃ -CaO-CaCO ₃ -CaSO ₄ -Fe ₂ O ₃ (chemical analysis value) ≦ −20% by weight 11. The pressurized fluidized bed boiler according to claim 10, wherein the lime fine particles are at least one of fine limestone, fine quicklime and fine slaked lime, and the particle size is 200 μm or less. Dust removal method. 12. The pressurizing apparatus according to claim 1, further comprising an emergency dust removing device for removing dust from high-temperature exhaust gas discharged when the pressurized fluidized-bed boiler is urgently depressurized. Dust removal device for fluidized bed boiler. 13. An emergency dust removing device, comprising: a spray type dust removing tower for removing dust from a high temperature exhaust gas discharged from a pressurized fluidized bed boiler at the time of emergency depressurization; and a water for storing water sprayed on the spray dust removing tower. The emergency dedusting device for a pressurized fluidized-bed boiler according to claim 12, further comprising a tank. 14. The spray-type dust removal tower according to claim 12, wherein the water tank is provided above the spray-type dust removal tower so that water can be supplied to the spray-type dust removal tower with a head difference even immediately after the power is turned off. Or an emergency dust remover for a pressurized fluidized-bed boiler according to 13. 15. A pressurized fluidizer according to claim 12, wherein a mist separator is provided downstream of said spray-type dedusting tower to discharge dehumidified exhaust gas to the atmosphere. Dust removal device for layer boiler. 16. A spray pipe is provided in a high-temperature duct for supplying high-temperature exhaust gas to the spray-type dedusting tower, and a shielding plate provided with a thermal expansion absorbing mechanism is provided inside the high-temperature duct. The dust removing device for a pressurized fluidized-bed boiler according to any one of claims 12 to 15. 17. The apparatus according to claim 12, wherein a slit portion is provided between the shield plates along the flow direction of the exhaust gas, and an expandable bellow is attached to the slit portion.
16. The dust removing device for a pressurized fluidized-bed boiler according to any one of 16.