JPH1054511A - Structure of branch part of ash transport tube for pressurized fluidized bed boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent ash from being accumulated, cooled and clinging to the side of a stop valve inlet of an ash transport pipe as bypass line. SOLUTION: An ash transport pipe 23 for feeding ash discharged from a cyclone within a pressure vessel is branched off to an ash transport pipe 25 as main line and to an ash transport pipe 26 as bypass line, a ball valve- structured stop valve 30 is provided in the course of the ash transport pipe 26. An inner cylinder 43 is fastened in a short pipe 26a connected to the inlet side of the stop valve 30 of the ash transport pipe 26 to blow bypass blow air AB to the side of a ball 32 of the stop valve 30 thereby enabling the discharging of ash to the side of the ash transport pipe 25. A cross bend 24 is provided in a main line and at the branched part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a branch structure of an ash transport pipe of a pressurized fluidized bed boiler, and more particularly to a pressurized fluidized bed in which ash does not accumulate on a stop valve inlet side of a branched bypass line to prevent cooling and sticking. The present invention relates to a structure of a ash transport pipe branch of a boiler.

[0002]

2. Description of the Related Art In recent years, pressurized fluidized-bed boilers have been developed in order to make effective use of energy.

[0003] An example of a conventional pressurized fluidized-bed boiler is shown in Fig. 4, in which 1 is a pressurized fluidized-bed boiler.

The pressurized fluidized-bed boiler 1 comprises a pressure vessel 2
In the pressure vessel 2, there is disposed an air conduit 6 extending downward with a boiler body 3 and a cyclone 4 and an ash cooler 5 in the middle.

[0005] The boiler body 3 is surrounded by a furnace wall formed by connecting a heat transfer tube and fins, and a furnace 7 is formed inside the furnace. A heating section 8 is housed therein, and a fuel injection nozzle 9 for injecting fuel into the furnace 7 through the pressure vessel 2 and the furnace wall of the boiler main body 3 is disposed below the furnace 7.

In the vicinity of the upper end of the ash hopper 10 provided at the lower part of the furnace 7, a plurality of sets of diffuser tubes 11 having a large number of ejection holes are provided at a predetermined pitch in a direction perpendicular to the plane of FIG. The end of the air conduit 6 is connected to the lower end of the air diffuser 11 through the ash hopper 10. Thus, the air in the pressure vessel 2 is introduced into the air conduit 6 from the upper end opening 6a, passes through the air conduit 6, and diffuses through the air diffuser 1
Bed material 12 mixed with a desulfurizing agent, sand, etc., which is jetted out of the nozzle 1 into the furnace 7 and stored in the furnace 7.
Can be fluidized.

[0007] At the upper end of the boiler body 3, a bed material 12 is provided.
The combustion gas G produced by burning fuel in the furnace 7 by the heat of the gas and heating the water in the heat transfer section 8 and the furnace wall tube
A manifold 13 for introducing B as exhaust gas GE is provided so as to extend upward.

An exhaust gas pipe 14 extending in the horizontal direction is connected near the upper end of the manifold 13.
Is connected to the outer periphery of the cyclone 4 in the tangential direction of the outer periphery of the cyclone 4.

An exhaust gas pipe 15 is connected to the top of the cyclone 4. The exhaust gas pipe 15 extends to the outside through the pressure vessel 2, and its tip is connected to a gas turbine 16. Thus, the gas turbine 16 can be driven by the exhaust gas GE sent from the manifold 13 through the exhaust gas pipe 14, the cyclone 4, and the exhaust gas pipe 15.

[0010] The gas turbine 16 can drive a generator 17 and a compressor 18 connected to the gas turbine 16. The compressed air AC generated by the compressor 18 is compressed air. It can be introduced into the pressure vessel 2 via a feed pipe 19.

The lower end of the cyclone 4 is connected to an ash transport pipe 20 for transporting the ash collected and separated by the cyclone 4 by a part of the exhaust gas GE.
The ash cooler 5 is connected to a lower end of a cooling pipe 22 which is bent and stored in a casing 21 in a zigzag manner.

An ash transport pipe 23 is connected to the upper end of the cooling pipe 22, extends through the pressure vessel 2 to the outside, and has a tip connected to an upper end of a cross bend 24 having a closed lower end. ing.

At the left and right ends of the cross bend 24, an ash transport pipe 25 constituting a main line and an ash transport pipe 26 constituting a bypass line are respectively connected to form a branch portion. The ash transport pipe 26 is connected to the top of the tank 27 and connected to the side of the vacuum tank 27.

Further, in the middle of the ash transport pipe 25, the on-off valve 2 is sequentially arranged from the cross bend 24 side to the pressure reducing tank 27 side.
8. An orifice 29 is provided, and a stop valve 30 is provided in the middle of the ash transport pipe 26.

The stop valve 30 has a ball valve structure, and details thereof are shown in FIGS. Thus, the casing 31 of the stop valve 30 has a spherical portion 31a and a cylindrical portion 31b that is connected to the front and rear of the spherical portion 31a and communicates with the ash transport pipe 26.
And a shaft guide cylinder 3 protruding in the horizontal direction on the side of the spherical portion 31a.
A ball 32 is fitted into the spherical portion 31a of the casing 31 so as to be rotatable in a direction parallel to a vertical plane extending in the direction of the axis L of the ash transport pipe 26.

When the ball 32 is rotated to open the stop valve 30, the ball 32 flows in the radial direction of the ball 32 so that the ball 32 can communicate with the ash transport pipe 26 connected before and after the stop valve 30. A road 32a is protruded.

A horizontal shaft 3 connected to one side of the ball 32
3 extends outwardly through the seal 34 and the bearing 35 fitted inside the shaft guide tube 31c, and the end thereof is
It is connected to a drive device 36 installed outside 1c.

A short pipe 26a located between the cross bend 24 of the ash transport pipe 26 and the stop valve 30 is formed in a tapered shape so that the inner diameter increases from the cross bend 24 side toward the stop valve 30. ing.

An ash transport pipe 37 is connected to the side of the decompression tank 27, which is different from the ash transport pipe 26 connection portion at an angle of approximately 180 degrees with respect to the circumferential direction, in the horizontal direction.
Is connected to the outer periphery of the cyclone 38 in a tangential direction.

The ash collected and separated by the cyclone 38 and discharged from the lower part thereof can be introduced into the ash cooler 39, and the ash discharged from the ash cooler 39 can be stored in the hopper 40. It has become.

In FIG. 4, reference numeral 41 denotes an ash extraction pipe connected to the lower part of the ash extraction hopper 10, and a part of the ash (bed material 12) generated by the combustion is removed from the space between the air diffusion pipes 11. The ash falls down to 10 and can be cut out from the ash extraction hopper 10 through the ash cut-out pipe 41. In FIG. 2, reference numeral 42 denotes ash accumulated in a portion hanging down below the cross bend 24.

When the pressurized fluidized bed boiler 1 is operated, a predetermined amount of bed material 12 is stored in the boiler main body 3 and the compressed air AC supplied to the pressure vessel 2 is supplied.
Is introduced into the boiler main body 3 from the air conduit 6 through the air diffuser 11, and the bed material 12 is fluidized in the boiler main body 3.

The fuel such as coal slurry injected into the boiler body 3 from the fuel injection nozzle 9 is burned by the heat of the bed material 12 or the like to generate a combustion gas GB.
B heats the fluid in the heat transfer section 8 and the heat transfer tube in the furnace wall of the furnace 7 while ascending in the furnace 7 to generate steam, and passes through the furnace 7 as a waste gas GE from the boiler body 3 to a manifold. It is discharged to 13.

Exhaust gas GE discharged to the manifold 13
Is introduced into the cyclone 4 from the manifold 13 through the exhaust gas pipe 14, the coal combustion ash and unburned coal particles are separated by the cyclone 4, introduced into the gas turbine 16 through the exhaust gas pipe 15, and discharged by the exhaust gas GE. Turbine 16
Is driven.

When the gas turbine 16 is driven, the generator 17 is driven to generate power and the compressor 18
Is driven, and the compressed air AC generated by the compressor 18 is introduced into the pressure vessel 2 through the compressed air supply pipe 19.

The steam generated by the boiler body 3 is used for driving a steam turbine (not shown).

The ash collected and separated by the cyclone 4 is transported through the ash transport pipe 20 by using a part of the exhaust gas GE as an ash transport gas, and is cooled by the ash cooler 5 to the cooling pipe 22.
While passing through the inside, it is cooled by the compressed air AC fed from above to below the air conduit 6, further transported through the ash transport pipe 23, and reaches the cross bend 24.

During normal operation, the on-off valve 28
Since the stop valve 30 is closed and the stop valve 30 is closed, the ash is introduced from the cross bend 24 into the pressure reducing tank 27 through the ash transport pipe 25 which is the main line. Since the orifice 29 is provided in the ash transport pipe 25, the cyclone 4 side has a high pressure and the decompression tank 27 side has a low pressure. Therefore, the ash collected and separated by the cyclone 4 is on the cyclone 4 side. Is smoothly introduced into the depressurizing tank 27 by the difference between the pressure in the depressurizing tank 27 and the pressure in the depressurizing tank 27, and further fed from the depressurizing tank 27 to the cyclone 38 via the ash transport pipe 37, and collected and separated by the cyclone 38 The ash is sent to the ash cooler 39, cooled by the ash cooler 39, and then introduced into the hopper 40.

When the load of the pressurized fluidized-bed boiler 1 is low, the flow rate of the exhaust gas GE is small, so that the flow rate of the carrier gas flowing into the ash transport pipes 23 and 25 from the cyclone 4 is small. Therefore, the ash transport pipe 2 before and after the orifice 29
Since the pressure difference in the inside 5 cannot be made large and the diameter of the orifice 29 is narrowed, it is difficult to transport the ash.

Therefore, in this case, the ball 32 is rotated by the driving device 36 to set the position of the flow passage 32a to the position indicated by the phantom line in FIG. 2, and the stop valve 30 is opened.

For this reason, the ash from the cyclone 4 is introduced into the decompression tank 27 through the ash transport pipe 23, the cross bend 24, and the ash transport pipe 26 which is a bypass line. Hopper 4
Sent to 0.

Since the cross bend 24 is provided,
In the part which hangs down from the horizontal part of the cross bend 24,
As shown in FIG. 2, the ash 42 accumulates, and therefore, abrasion of the pipe at the branch portion can be prevented.

[0033]

During normal operation of the pressurized fluidized-bed boiler 1, since the stop valve 30 is closed, the pocket X where there is no gas flow at the inlet side of the stop valve 30 is shown in FIG. As shown, the ash accumulates and cools and solidifies.

Accordingly, ash clogging occurs in the pocket portion X. As a result, even when the stop valve 30 is opened when the pressurized fluidized-bed boiler 1 is under a low load, ash is transferred from the ash transport pipe 26 to the pressure reducing tank 2.
7 can not be sent.

The present invention has been made in view of the above circumstances, and has as its object to prevent ash from accumulating in a pocket portion on the inlet side of a stop valve where there is no gas flow to prevent cooling and sticking.

[0036]

According to the present invention, there is provided an ash transport pipe for feeding ash discharged from a cyclone in a pressure vessel, an orifice provided in an intermediate portion, and ash fed into a vacuum tank. The ball is branched into a main line to be obtained and a bypass line provided with a ball valve in the middle and capable of feeding ash into the decompression tank. The first side of the cylinder is fixed to the inner periphery of the bypass line so that blow air introduced from the outside can be blown toward the ball of the ball valve between the outer periphery of the inner cylinder and the inner periphery of the bypass line. Between the ball valve end of the inner cylinder and the ball, the ash blown off by the blow air blown from the first gap to the ball, and the ash blown by colliding with the ball and inverted. And through the inner cylinder In which as to form a second gap may delivered to.

In the present invention, a cross bend is preferably provided at a branch between the main line and the bypass line.

By introducing the blow air into the first gap, the blow air is blown from the first gap to the ball of the ball valve, collides with the ball and reverses, and the ash accompanies the second gap. From the inner cylinder to the main line.

Since ash can be prevented from accumulating on the inlet side of the ball valve, the ash is not clogged and clogged at the corresponding portion, so that no trouble occurs when the ash is transported from the bypass line.

When a cross bend is provided at the branch between the main line and the bypass line, it is possible to prevent the branch from being worn by ash transported from the cyclone.

[0041]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of an embodiment of the present invention, in which an inside and outside diameter of a short pipe 26a is inserted into a short pipe 26a of an ash transport pipe 26 interposed between a cross bend 24 and a stop valve 30. A hollow inner cylinder 43 having substantially the same diameter as the small diameter portion is inserted, and the end of the inner cylinder 43 on the cross bend 24 side is fixed concentrically to the inner circumference of the short pipe 26a by welding or the like. A gap Y is formed between the inner tube 43 and the inner peripheral tapered portion of the short pipe 26a, and a gap Z is formed between the end of the inner cylinder 43 on the stop valve 30 side and the ball 32 of the stop valve 30.

A bypass blow air supply nozzle 45 is connected to the tapered portion of the short pipe 26a so as to communicate with the gap Y.
From a not-shown air supply source, via a pipe line 47 having an on-off valve 46 and a bypass blow air supply nozzle 45,
The bypass blow air AB can be supplied into the gap Y of the short pipe 26a.

Next, the operation of the embodiment of the present invention will be described with reference to FIG.

During normal operation of the pressurized fluidized-bed boiler 1,
The flow passage 32a of the ball 32 is positioned as shown in FIG. 1 so that the flow passage 32a does not communicate with the ash transport pipe 26.

When the pressurized fluidized-bed boiler 1 is operated normally, the on-off valve 4 is opened at predetermined time intervals (one time / 4 hour).
6, the bypass blow air AB is supplied to the gap Y in the short pipe 26a via the pipe line 47 and the bypass blow air supply nozzle 45.

Then, the bypass blow air AB is
The ball 32 of the stop valve 30 is guided to the outer peripheral side of the inner cylinder 43.
The ash transport pipe 25 passes through the hollow portion of the inner cylinder 43 and passes through the horizontal portion of the cross bend 24, accompanied by the ash retained in the pocket portion X, and is reversed by colliding with the ball 32. The ash is transported to the hopper 40 from the ash transport pipe 25 via the decompression tank 27, the cyclone 38 and the ash cooler 39.

By blowing the bypass blow air AB into the pocket portion X at predetermined time intervals as described above, it is possible to prevent the ash from accumulating in the pocket portion X and cooling and sticking, thereby extending the stop valve. It is possible to prevent clogging of the pocket portion X on the 30 entrance side with ash.

The embodiment of the present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the spirit of the present invention.

[0050]

According to the ash transfer pipe branch structure of the pressurized fluidized bed boiler of the present invention, in the case of the first and second aspects, the ash is formed in the pocket on the ball valve inlet side in the bypass line branched from the ash transfer pipe. Is not likely to accumulate, cool and stick,
It is possible to prevent the ash from being clogged on the ball valve inlet side, and it is possible to achieve an excellent effect that the wear of the pipe at the branch portion can be prevented.

[Brief description of the drawings]

FIG. 1 is a side view, partly in longitudinal section, showing an example of an embodiment of a branch structure of an ash transport pipe of a pressurized fluidized bed boiler of the present invention.

FIG. 2 is a side view, partly in longitudinal section, showing an example of a conventional ash transport pipe branch part structure of a pressurized fluidized bed boiler.

FIG. 3 is a view taken in the direction of arrows III-III in FIG. 2;

FIG. 4 is a general system diagram of a pressurized fluidized bed boiler.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressurized fluidized-bed boiler 2 Pressure vessel 4 Cyclone 23 Ash transport pipe 24 Cross bend 25 Ash transport pipe (main line) 26 Ash transport pipe (bypass line) 27 Decompression tank 29 Orifice 30 Stop valve (ball valve) 32 Ball 43 Inside Tube Y gap (first gap) Z gap (second gap) AB Bypass blow air (blow air)

Claims (2)

[Claims] An ash transport pipe for feeding ash discharged from a cyclone in a pressure vessel, a main line having an orifice in the middle and capable of feeding ash into a pressure reducing tank, and a middle line. Branch to a bypass line equipped with a ball valve and capable of feeding ash into the vacuum tank,
An inner cylinder is inserted into the bypass line at the ball valve inlet side, and the anti-ball valve side of the inner cylinder is fixed to the inner circumference of the bypass line, and a blow introduced from the outside between the inner cylinder outer circumference and the bypass line inner circumference. A first gap is provided so that air can be blown toward the ball of the ball valve, and blown off by the blow air blown from the first gap to the ball between the ball valve tip of the inner cylinder and the ball. Ash transport pipe for a pressurized fluidized-bed boiler, characterized in that a second gap is formed so that the blown ash can be fed into the main line through the inner cylinder together with the blown air inverted by colliding with the ball. Branch structure. 2. The branch structure of an ash transport pipe of a pressurized fluidized-bed boiler according to claim 1, wherein a cross bend is provided at a branch portion between the main line and the bypass line.