JP2909298B2 - Fluidized bed height control device for combustion furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bed height control apparatus for a fluidized bed of a combustion furnace such as a pressurized fluidized bed boiler.

[0002]

2. Description of the Related Art The present applicant has proposed a bed height control apparatus for a fluidized bed of a combustion furnace in Japanese Patent Application No. 4-63359. An apparatus according to an embodiment of the present invention will be described with reference to FIG.

[0003] Reference numeral 1 denotes a combustion furnace in which a pressurized fluidized bed is formed by a fluidizing material 12.
Coal 4 and limestone 5 as a desulfurizing material are pneumatically transported in the direction indicated by arrow 25 by air 6 flowing in the direction indicated by reference numeral 6. In addition, air 6 is supplied to the lower part of the combustion furnace 1 below the air distribution plate 2 as combustion air.

The combustion gas from the combustion furnace 1 is discharged from the upper part of the combustion furnace 1 as shown by an arrow 27, passes through a cyclone dust collector 7, a high-temperature ceramic dust collector (precision dust remover) 8, and a gas turbine 9 Supplied to On the other hand, a heat transfer tube 3 to which the pressurized water 10 is supplied is provided in the pressurized fluidized bed as shown by an arrow 31, and steam generated in the heat transfer tube 3 is:
It is supplied to the steam turbine 11 as shown by an arrow 32.

A fluid material hopper 13 has an upper portion connected to a lower portion of the pressurized fluidized bed by a fluidized material transport pipe 18, and a supply pipe for sending the fluidized material from the bottom of the hopper 13 to the lower portion of the pressurized fluidized bed. 18 'are provided.

Reference numeral 14 denotes a steam turbine 11 as shown by an arrow 30 through a line having a control valve 15 and a flow meter 16.
The steam extracted from the ejector is an ejector supplied as a driving fluid, and the suction side of the ejector 14 is a gas suction pipe 1
7 is connected to the upper part of the fluidized material hopper 13.
The discharge side of the ejector 14 is provided with a cyclone dust collector 7.
Combustion gas pipe 40 between the high temperature ceramic dust collector 8 and
It is connected to the.

An air inlet pipe 6a branched from a pipe of air 6 for transporting the coal 4 and the limestone 5 by air is provided. The air inlet pipe 6a is connected to an air nozzle 20 via an air flow meter 22 and an air flow control valve 21. The air nozzle 20
Changes its direction in the vertical direction from the obliquely upwardly inclined portion of the fluid material transport pipe 18 and opens upward in the fluid material transport pipe 18 at a portion 18a immediately after the suction port of the transport material transport pipe 18; Air is supplied in the direction in which the fluid material 12 flows. Reference numeral 24 denotes a differential pressure gauge for detecting a pressure difference between the pressurized fluidized bed and the fluid material hopper 13, that is, a pressure difference between the upstream side and the downstream side of the fluid material transport pipe 18. The controller 23 controls the air flow control valve 21 based on the differential pressure signal detected by the differential pressure gauge 24 and the air flow signal detected by the air flow meter 22 so that the air flows from the air nozzle 20. The differential pressure is maintained at a target value by controlling the flow rate of air supplied to the material transport pipe 18.

In this device, the suction force generated in the ejector 14 by the steam from the steam turbine 11 reduces the pressure inside the fluidized material hopper 13 and generates a pressure difference between the hopper 13 and the combustion furnace 1. Combustion furnace 1 by pressure
The gas in the furnace flows into the fluidized material hopper 13 through the fluidized material transport pipe 18 as shown by an arrow 28, and the gas in the furnace pneumatically transports the fluidized material 12 to the fluidized material hopper 13. Fluid material 1
Numeral 2 drops by gravity in the fluid material hopper 13 and accumulates on the bottom of the hopper 13.

In this way, the fluid material 12 is sent from the combustion furnace 1 to the fluid material hopper 13, and the suction force of the ejector 14 is controlled by the flow control valve 15, so that the fluid material 12 is sent to the fluid material hopper 13. Of the combustion furnace 1 is controlled.
The height of the pressurized fluidized bed can be increased or decreased according to the level of the load.

The furnace gas entering the fluidized material hopper 13 is recovered by the ejector 14 through the gas suction pipe 17 into the combustion gas pipe 40 on the downstream side of the cyclone dust collector 7 and discharged to the atmosphere. Without being sent to the gas turbine 9, and a decrease in thermal efficiency can be prevented.

Further, the differential pressure between the upstream side and the downstream side of the fluidized material transport pipe 18 is detected by a differential pressure gauge 24, and the signal thereof is inputted to a controller 23. Based on the signal, the air flow control valve 21 is controlled. A controlled flow rate of air is introduced from the air nozzle 20 to the fluidized material transport pipe 18 to maintain the differential pressure at the target differential pressure. In addition, air is injected from the air nozzle 20 in the flowing direction of the fluidized material 12 in the fluidized material transport pipe 18 to reduce the density of the fluidized material 12 and promote the air transport. Therefore, even if the set target differential pressure is low, the fluid material 1
2 can be smoothly transported to the fluid material hopper 13, and accordingly, the flow rate of steam sent to the ejector 14 as a driving fluid can be reduced.

[0012]

The apparatus according to Japanese Patent Application No. 4-63359 proposed by the present applicant shown in FIG.
The horizontal portion 1 is located on the fluid material hopper 13 side of the fluid material transport pipe 18.
8b, the fluid material 12 accumulates in the horizontal portion 18b as shown by reference numeral 19, and the pressure loss in the transport pipe 18 increases. For this reason, in order to suck and transport a required amount of the fluid material 12 to the fluid material hopper 13, the ejector 14
It is necessary to increase the flow rate of the steam for driving the steam. Further, since the fluidized material 12 accumulates in the fluidized material transport pipe 18, it becomes impossible to transport the fluidized material 12 quantitatively, and the fluidized bed cannot be lowered to a required height.

An object of the present invention is to provide a fluidized bed height control apparatus for a combustion furnace which can solve the above problems.

[0014]

Means for Solving the Problems The bed height control apparatus for a fluidized bed of a combustion furnace according to the present invention employs the following means. (1) A combustion furnace having a fluidized bed, a fluidized material hopper, a fluidized material transport pipe connecting a lower portion of the fluidized bed and the fluidized material hopper to move the fluidized material from the fluidized bed to the fluidized material hopper, and discharge. A bed height control device for a fluidized bed of a combustion furnace having a gas suction pipe connecting a suction side of an ejector connected to a combustion gas pipe of the combustion furnace with the fluidized material hopper; The combustion furnace side portion is a double pipe composed of an inner cylinder and an outer cylinder and opened to the combustion furnace, and air is injected between the inner cylinder and the outer cylinder of the double pipe. . (2) a combustion furnace having a fluidized bed, a fluidized material hopper, a fluidized material transport pipe connecting the lower part of the fluidized bed and the fluidized material hopper to move the fluidized material from the fluidized bed to the fluidized material hopper, and discharge A bed height control device for a fluidized bed of a combustion furnace having a gas suction pipe connecting a suction side of an ejector connected to a combustion gas pipe of the combustion furnace with the fluidized material hopper; A fluid material hopper side portion is inclined downward toward the fluid material hopper at an angle of repose greater than the angle of repose of the fluid material, and an air injection nozzle is provided above the inclined portion.

[0015]

In the present invention (1), the air introduced into the annular portion between the inner cylinder and the outer cylinder of the fluid material transport pipe is blown out from the double pipe into the combustion furnace. Is done. This air is blown into the inner tube together with the fluidized material and the gas in the furnace of the combustion furnace, thereby reducing the particle concentration of the fluidized material in the inner cylinder, reducing pressure loss, and accumulating the fluidized material in the fluidized material transport pipe. Is prevented.

In the present invention (2), the portion of the fluid material transport pipe on the fluid material hopper side is inclined downward toward the fluid material hopper beyond the angle of repose of the fluid material, so that the fluid material accumulates And the pressure loss is reduced. Also, when the angle of repose of the flowing material becomes large and the flowing material becomes difficult to flow due to factors such as fragments of refractory material and mixing of clinker, the flowing material is blown off by blowing air from the air injection nozzle, It is possible to eliminate the accumulation of wood.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. In the present embodiment, the apparatus according to the present applicant's proposal shown in FIG. 3 is improved as described below, and the same portions are denoted by the same reference numerals and description thereof will be omitted.

In this embodiment, a gas flow meter 31 is provided in the gas suction pipe 17, and a signal from the gas flow meter 31 is input to the adjustment setting device 32. Further, a signal of the flow meter 16 of the steam line for driving the ejector is input to the adjustment setting device 32, and the signal of the adjustment setting device 32 is used to output the flow control valve 1.
5 is controlled. Further, the adjustment setter 32 is connected to the controller 23 so that signals are exchanged between the two.

The fluid material transport pipe 18 is open to the fluid material hopper 13 following a portion 18c inclined obliquely upward from the combustion furnace 1, a portion 18d extending vertically upward following the portion 18c, and a portion 18d extending vertically upward. A double pipe comprising a horizontal portion 18b, and an inner tube 18e connected to the portion 18d and an outer tube 18f arranged at an interval outside the inner tube 18e is provided in the portion 18c. The double tube opens into the combustion furnace 1 and an annular space between the inner cylinder 18e and the outer cylinder 18f is formed at the upper end thereof by a flange 18.
g closed.

On the other hand, an air pipe 6b branched from the pipe of the air 6 and having an air flow meter 22 'and an air flow control valve 21' is provided. The air pipe 6b is an inner pipe 18e and an outer pipe 18f of the double pipe. Are connected to an annular space between them. The signal from the air flow meter 22 'is input to the controller 23, and the signal from the controller 23 controls the air flow control valve 21'.

Reference numeral 33 denotes a differential pressure gauge for detecting a differential pressure between the upper and lower portions of the pressurized fluidized bed, and requires a value obtained by multiplying a value of a change in the differential pressure detected by the differential pressure gauge 33 by a sectional area of the combustion furnace. By dividing by the time, the weight flow rate of the fluid material 12 can be obtained.

In this embodiment, when the load reduction rate of the combustion furnace 1 is determined, the value of the flow rate of the fluidized material 12 sent to the fluidized material hopper 13 is given. A signal is sent to the air flow control valve 21 via the controller 23 and the air flow control valve 21, and a predetermined flow rate of the in-furnace gas flows from the combustion furnace 1 with the suction force of the ejector 14 and the air flow rate supplied from the air nozzle 20 as predetermined values. The fluid material 1 is sucked through the material transport pipe 18 and the fluid material 1 at a predetermined flow rate
2 is sent to the fluid material hopper 13 via the fluid material transport pipe 18. The in-furnace gas sent to the fluidized material hopper 13 is sucked by the ejector 14 and collected by the combustion gas pipe 40 to prevent a decrease in thermal efficiency.

A predetermined flow rate of air flows through the air pipe 6b by an air flow control valve 21 'controlled by a controller 23. The air flows between the inner cylinder 18e and the outer cylinder 18f of the double pipe. It is thrown into the annular space and blown into the combustion furnace 1. As a result, the particle concentration of the fluidized material 12 flowing into the inner cylinder 18e is reduced, the pressure loss in the fluidized material transport tube 18 is reduced, and the fluidized material 12 is smoothly dispersed in the fluidized material transport tube 18 by the flow of the furnace gas. Is prevented from accumulating.

The flow rate of the gas flowing through the gas suction pipe 17 is the sum of the flow rate of the in-furnace gas flowing through the fluidized material transport pipe 18 and the flow rate of the air supplied to the transport pipe 18. On the other hand, the flow rate of the fluid material 12 transported in the fluid material inner cylinder 18e is the same.
It is determined by the flow rate of the furnace gas flowing through the inner cylinder 18e . A signal of the gas flow rate from the gas flowmeter 31 and a signal of the flow rate of the input air from the air flowmeters 22 and 22 'are input to the adjustment setter 32, and the difference between them is obtained to determine the difference between the signals in the inner cylinder 18e . The flow rate of the furnace gas flowing through the
Based on this, the flow rate of the fluid material 12 is determined. Therefore, when the flow rate of the furnace gas fluctuates from a predetermined value,
Controls air input flow rate from the regulated setting device 32 suction force of the flow control valve 15 and the ejector 14 and outputs the signal to the air flow control valve 21, 21 'into the fluidized material transport pipe 18, whereby the flow material within the barrel The flow rate of the gas inside the furnace 18e is set to a predetermined value, and the flow rate of the fluidized material 12 is set to a predetermined value accordingly, so that the bed height of the pressurized fluidized bed can be accurately controlled.

Further, when the flow rate of the fluidized material 12 moving inside the fluidized material transport pipe 18 changes, the fluidized material transport pipe 1 is moved.
Although the pressure loss of the solid-gas two-phase flow in the pipe 8 changes, the signal based on the flow rate of the gas in the furnace in the pipe 18e of the fluidized material, that is, the flow rate of the fluidized material 12, calculated by the adjustment setter 32 as described above. To the flow control valve 15 to control the steam flow rate and control the suction force of the ejector 14, thereby compensating for the pressure loss and smoothly sending the fluid material 12 from the combustion furnace 1 to the fluid material hopper 13. And the amount of steam used can be reduced.

A second embodiment of the present invention will be described with reference to FIG. The present embodiment is an improvement of the apparatus shown in FIG. 3 according to the applicant's proposal shown in FIG. 3 as described below. The same parts are denoted by the same reference numerals and the description thereof will be omitted. Omitted.

In this embodiment, a portion 34 which opens into the fluid material hopper 13 is provided following a portion 38 of the fluid material transport pipe 18 which extends vertically upward, and this portion 34 is formed at an angle larger than the repose angle of the fluid material 12. It is inclined downward toward the fluid material hopper 13 at θ. In addition, an air pipe 6c is provided which branches from a pipe for the air 6, and an air nozzle opening to an L-shaped part 39 to which the on-off valve 36 and the above-mentioned parts 32 and 34 of the fluid material transport pipe 18 are connected. 37 are provided. Further, a differential pressure gauge 35 for detecting a differential pressure between the fluid material hopper 13 and the L-shaped portion 39 is provided, and an on-off valve 36 is controlled by a signal from the differential pressure gauge 35.

FIG. 2 shows suction and transport of the gas in the furnace and the fluid 12 in the combustion furnace 1 to the fluid material hopper 13 by the ejector 14 and the introduction of air into the fluid material transport pipe 18 in this embodiment. Same as the device.

In the present embodiment, since the portion 34 of the fluid material transport pipe 18 on the fluid material hopper 13 side is inclined downward more than the angle of repose of the fluid material 12, the fluid material 12
4, the fluidized material 12 does not accumulate in the fluidized material transport pipe 18.

Also, for some reason, the portion 34
When the flow material 12 accumulates, the differential pressure detected by the differential pressure gauge 35 becomes equal to or higher than the set value. At this time, the on-off valve 36 is opened by the signal of the differential pressure gauge 35, and the air is injected from the air nozzle 37. 12 is blown off and stored in the fluid material hopper 13. When the flowing material 12 is blown off, the differential pressure detected by the differential pressure gauge 35 returns to a normal value, and the on-off valve 36 is closed by the signal to stop the air supply.

Thus, in this embodiment, the fluid material 1
2 can be smoothly transported in the fluid material transport pipe 18.

The fluid material 12 has a particle size of 0.8 to 1.
When using 6mm limestone, its angle of repose is 40 °
And the inclination angle of the portion 34 of the fluid material transport pipe 18 is 4
It is set to 0 ° or more.

In the first and second embodiments, the bed height of the pressurized fluidized bed is controlled. However, the present invention can be applied to the case where the bed height of a normal pressure fluidized bed is controlled. .

[0034]

As described above, according to the present invention, the fluidized material can be smoothly fed from the combustion furnace to the fluidized material hopper by the provision of the first and second aspects of the present invention. In addition, the bed height of the fluidized bed of the combustion furnace can be accurately controlled. The present invention also provides an ejector for reducing the pressure loss in the fluidized material transport pipe or preventing the accumulation of the fluidized material, thereby sucking the gas in the furnace of the combustion furnace and the fluidized material from the combustion furnace to the fluidized material hopper. , The flow rate of the driving fluid can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a system diagram of a second embodiment of the present invention.

FIG. 3 is a system diagram of a conventional bed height control device for a fluidized bed of a combustion furnace.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Combustion furnace 3 Heat transfer tube 4 Coal 5 Limestone 7 Cyclone dust collector 8 High temperature ceramic dust collector (precision dust collector) 9 Gas turbine 11 Steam turbine 13 Fluid material hopper 14 Ejector 15 Flow control valve 16 Flow valve 17 Gas suction pipe 18 Fluid material transport pipe 18e Inner cylinder 18f Outer cylinder 21, 21 'Air flow control valve 22, 22' Air flow meter 23 Controller 24 Differential pressure gauge 31 Gas flow meter 32 Adjustment setting unit 34 Part of fluid material transport pipe 35 Differential pressure gauge 36 On-off valve 37 Air nozzle 38 Fluid material transport pipe

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F23C 11/02 305 F23C 11/02 308

Claims (2)

(57) [Claims] A combustion furnace having a fluidized bed, a fluidized material hopper, and a fluidized material transport pipe connecting a lower portion of the fluidized bed and the fluidized material hopper to move the fluidized material from the fluidized bed to the fluidized material hopper; And a bed height control device for a fluidized bed of a combustion furnace provided with a gas suction pipe connecting a suction side of an ejector whose discharge side is connected to a combustion gas pipe of the combustion furnace and the fluidized material hopper. The portion of the tube on the combustion furnace side is a double tube comprising an inner cylinder and an outer cylinder and opening to the combustion furnace, and air is injected between the inner cylinder and the outer cylinder of the double pipe. A bed height control device for a fluidized bed of a combustion furnace. 2. A combustion furnace having a fluidized bed, a fluidized material hopper, and a fluidized material transport pipe connecting a lower portion of the fluidized bed and the fluidized material hopper to move the fluidized material from the fluidized bed to the fluidized material hopper, And a bed height control device for a fluidized bed of a combustion furnace provided with a gas suction pipe connecting a suction side of an ejector whose discharge side is connected to a combustion gas pipe of the combustion furnace and the fluidized material hopper. A fluidized bed of a combustion furnace, characterized in that a portion of the tube on the fluidized material hopper side is inclined downward toward the fluidized material hopper at an angle of repose greater than the angle of repose of the fluidized material, and an air injection nozzle is provided above the inclined portion. Layer height control device.