JP2004279004A - L-valve type loop seal for circulation fluidized bed incinerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a L-valve type loop seal for a circulation fluidized bed incinerator, ensuring stable operation of an incinerator without increasing the size thereof. <P>SOLUTION: The L-valve type loop seal 9 for the circulation fluidized bed incinerator is formed in a L-shape ranging from a hollow rising portion 8a of the bottom of a downcomer 8 to a horizontal pipe 11 connected thereto for temporarily storing fluid medium moving down from a cyclone into the downcomer 8 to seal a fluid layer in a riser from the cyclone. A pipe member 13 is provided for expansively changing the inner diameter of the horizontal pipe 11 in the vertical direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an L-valve type loop seal for a circulating fluidized bed incinerator that can guarantee stable operation without increasing the size of the incinerator.
[0002]
[Prior art]
BACKGROUND ART Conventionally, a circulating fluidized bed incinerator 1 as shown in FIG. 5 is known as a facility for incinerating incineration materials such as sludge. In the incinerator 1, the incineration material is incinerated while a certain amount of fluid medium F such as silica sand is circulated in the incinerator 1. Fluid medium F, which is filled in a hearth section 3 at the bottom of riser 2 in a heated state, is fluidized by primary air for combustion introduced from primary air introduction pipe 4 to form fluidized bed 5. The materials to be incinerated put into the layer 5 are mixed and stirred by the fluid medium F to be atomized, and are dried and thermally decomposed and incinerated. The incinerated matter incinerated in the fluidized bed 5 is further thermally decomposed by secondary air for combustion introduced from a secondary air introduction pipe above the fluidized bed 5 (not shown), and is further in the riser 2 together with the fluidized medium F and exhaust gas. And is sucked into the cyclone 7 via the horizontal duct 6 above the riser 2.
[0003]
The cyclone 7 separates and collects the fluid medium F blown up therefrom from the exhaust gas containing the incinerated ash of the incinerated material, and the collected fluid medium F is a hollow medium provided in the vertical direction. It descends in the downcomer 8 and is stored in the loop seal 9 at the bottom. Thereafter, the fluid medium F is returned to the hearth 3 via the return pipe 10 inclined downward, and circulated in the incinerator 1.
[0004]
The loop seal 9 disposed between the downcomer 8 and the return pipe 10 provides a gas flow in the cyclone 7 when the primary gas or exhaust gas in the fluidized bed 5 flows back toward the cyclone 7 through the downcomer 8. Is disturbed and the collection efficiency of the fluid medium F decreases, so that the fluid medium F is temporarily stored in order to suppress this, and the fluid bed 5 and the cyclone 7 are shut off and sealed. It has become. In the loop seal 9, the fluidized medium F is fluidized so that the amount of fluidized medium stored in the loop seal 9 is kept constant and the amount of fluidized medium in the riser 2 is not insufficient. In order to return to 3, the flowing air is introduced from a not-shown flowing air introducing pipe.
[0005]
Known as such a loop seal 9 is an L-valve type, an N-valve type, a seal pot, or the like. 6, the L-valve type loop seal 9 is formed in an L-shape from a hollow rising portion 8a at the bottom of the downcomer 8 to a cylindrical horizontal pipe 11 connected thereto. Then, in the L-valve loop seal 9, the downcomer 8 is started up while fluidizing the fluid medium F with the fluidizing air introduced from the fluidizing air pipe 12 and gradually flowing it out to the return pipe 10. The fluid medium F falling toward the return pipe 10 while falling from the portion 8 a into the horizontal pipe 11 is retained in the horizontal pipe 11, whereby a certain amount of the fluid medium F having a constant height in the downcomer 8 is obtained. The fluid medium F can be stored.
[0006]
Since the L-valve type loop seal 9 has a simple pipe structure of the rising portion 8a and the horizontal pipe 11, there is an advantage that there are few problems such as blockage and maintenance is easy even if blockage occurs. Further, not only is the structure simple, but also the horizontal length of the horizontal pipe 11 required for retaining the flowing medium F at a considerable height at the bottom of the downcomer 8 by retaining the flowing medium F therein. Generally, L is about twice as large as the inner diameter D (L / D = 2), and the loop seal 9 can be made compact. Patent Document 1 discloses an example of a circulating fluidized bed incinerator 1 employing such an L-valve type loop seal 9. The applicant of the present application has filed Japanese Patent Application No. 2002-359390 as a related prior application.
[0007]
[Patent Document 1]
JP-A-2002-286216
[Problems to be solved by the invention]
By the way, although the conventional L-valve type loop seal 9 has various advantages such as a simple structure as described above, there are cases where the circulating fluidized bed incinerator 1 cannot be operated stably. The present inventor has learned.
[0009]
Specifically, when the size of the incinerator 1 is increased, the flow state of the fluidized medium F in the fluidized bed 5, the temperature in the furnace, the incineration amount of the incinerated material, and the moisture content of the incinerated material are changed, this may occur. Accordingly, the circulation amount of the fluid medium F fluctuates. Due to the influence of the fluctuation, the fluid medium F is appropriately retained inside the horizontal pipe 11 in which the horizontal length L is set to about twice the inner diameter D. The flow medium F flows out of the return pipe 10 even when the supply of the flow air is stopped, and the flow medium F is stored at a constant height in the L-valve type loop seal 9. It turns out that there are times when it is not possible. In such a case, primary gas or the like flows back to the cyclone 7 because sufficient sealing performance cannot be ensured, and it becomes difficult to guarantee stable operation of the incinerator 1. I will.
[0010]
In order to cope with this, it is conceivable to set the horizontal length L of the horizontal pipe 11 to at least twice the inner diameter D, but if the length of the horizontal pipe 11 is increased in this way, the incinerator 1 becomes large. Therefore, various problems such as the manufacturing cost and the installation space arise.
[0011]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and provides an L-valve type loop seal of a circulating fluidized bed incinerator that can guarantee stable operation without increasing the size of the incinerator. The purpose is to provide.
[0012]
[Means for Solving the Problems]
The L-valve type loop seal of the circulating fluidized bed incinerator according to the present invention is formed in an L shape from the hollow rising portion at the bottom of the downcomer to the horizontal pipe connected thereto, and descends from the cyclone inside the downcomer. In the L-valve loop seal of a circulating fluidized bed incinerator that temporarily stores the flowing fluid medium and seals between the fluidized bed in the riser and the cyclone, the vertical inner diameter of the horizontal pipe is scalably changed. A pipe diameter adjusting means is provided.
[0013]
The vertical inner diameter of the horizontal pipe is changed by the pipe diameter adjusting means, and by reducing the inner diameter, the apparent horizontal length of the horizontal pipe can be extended, that is, for example, the horizontal length When the dimension is twice the inner diameter, the horizontal length can be increased to twice or more the inner diameter by reducing the inner diameter, so that the fluid medium can appropriately stay in the horizontal pipe, The fluid medium can be stored at a certain height in the L-valve loop seal.
[0014]
In particular, changing the inner diameter in the vertical direction with respect to the flowing medium that moves to the return pipe with the action of collapsing in the direction of gravity is more effective in changing the inner diameter in the horizontal direction than in changing the inner diameter in the horizontal direction. Can be effectively suppressed, the effect of reducing the inner diameter of the horizontal pipe can be further increased, and the fluid medium can appropriately stay in the horizontal pipe. As a result, the sealing function of the L-valve type loop seal can be properly secured without extending the length of the horizontal pipe, and thus without increasing the size of the circulating fluidized bed incinerator, and stably operating the incinerator. It is possible to guarantee.
[0015]
Further, the pipe diameter adjusting means is characterized in that at least the inner diameter in the vertical direction decreases from the lower side in the vertical direction to the upper side. With this configuration, when the inner diameter in the vertical direction of the horizontal pipe is reduced by the pipe diameter adjusting means, the inner diameter is reduced with the rise of the inner bottom surface of the horizontal pipe, and the flow of the fluid medium into the horizontal pipe is reduced. Further, the flow medium can be held more reliably by the L-valve type loop seal.
[0016]
Further, the pipe diameter adjusting means changes the inner diameter ratio in the vertical direction from 1 to 1/2. By setting the ratio of the inner diameter dimension change in the vertical direction to about 1/2, it is possible to prevent the horizontal pipe from being blocked by the flowing medium.
[0017]
Further, the pipe diameter adjusting means is a pipe member having an elliptical pipe formed therein and rotatable around a horizontal axis of the horizontal pipe. By this, it is possible to change the vertical inner diameter of the horizontal pipe in a freely expandable and contractable manner only by rotating the pipe member and changing the direction of the internal elliptical pipe, and the structure is simple and Good adjustment operability can be ensured.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of an L-valve type loop seal of a circulating fluidized bed incinerator according to the present invention will be described in detail with reference to the accompanying drawings. The L-valve loop seal 9 according to the present embodiment is based on the incinerator 1 shown in FIGS. 5 and 6 and is a pipe for changing the inner diameter in the vertical direction of the horizontal pipe 11 shown in FIGS. It is provided with a piping member 13 as a diameter adjusting means. The horizontal pipe 11 is detachably attached to a downcomer-side pipe end 11a communicating with the rising portion 8a at the bottom of the downcomer 8 and a return pipe-side pipe end 11b communicating with the return pipe 10. It is constituted by providing the piping member 13 in the first embodiment.
[0019]
Like the conventional horizontal pipe 11, each of the pipe ends 11a and 11b is formed in a cylindrical shape having a constant inner diameter (D as in the conventional case) and an outer diameter, and has a circular pipe 14 inside. Is formed. On the other hand, the pipe member 13 has an oval pipe 15 formed therein. The pipe member 13 has a cylindrical outer peripheral surface whose outer diameter dimension matches the outer diameter dimension of each of the pipe ends 11a and 11b, while the inner peripheral surface has a major axis dimension X whose length is equal to each of the pipe ends 11a and 11b. The minor axis dimension Y, which is the same as the inner diameter dimension D of 11b, is formed by a half of the cylindrical surface having an elliptical cross section of D / 2, and the cylindrical surface defines the elliptical conduit 15. Accordingly, the elliptical pipe 15 of the pipe member 13 is in communication with the circular pipe 14 of the pipe ends 11a and 11b in a manner of being inscribed therein. When the pipe member 13 is rotated around the horizontal axis of the horizontal pipe 11 including the pipe ends 11a and 11b and the pipe member 13, the elliptical pipe 15 orbits within the diameter D of the circular pipe 14. It has become.
[0020]
Annular pipe-side flanges 16 are formed at both ends of the pipe member 13, and annular pipe-end-side flanges 17 that are joined to the pipe-side flanges 16 are formed at the ends of the pipe ends 11a and 11b. Is done. Bolt holes 18 are formed in the flanges 16 and 17 at the same pitch, and are fastened by fastening means 19 such as bolts and nuts through the bolt holes 18 to connect the pipe member 13 to the respective pipe ends 11a and 11b. Removably connected. By shifting the pipe side flange 16 in the circumferential direction with respect to the pipe end side flange 17, the pipe member 13 is rotatably rotated around the horizontal axis of the horizontal pipe 11, whereby the ellipse with respect to the circular pipe line 14 is formed. The position of the shape conduit 15 is changed.
[0021]
Assuming that the major axis X shown in FIG. 2 is in the horizontal state at 0 °, while the minor axis Y is rotated to 90 ° at which the minor axis Y is in the horizontal state, the vertical direction of the horizontal pipe 11 is changed by the elliptical conduit 15 while the pipe member 13 rotates. The inner diameter is changed to be freely expandable and contractable. In particular, while the elliptical pipe 15 is circulated in the range of 0 ° to 90 ° with respect to the circular pipe 14, at least the vertical inner diameter of the horizontal pipe 11 is increased from vertically downward to upward, that is, The inner bottom surface of the conduit 15 of the piping member 13 is raised with respect to the inner bottom surface of the conduit 14 at the pipe ends 11a and 11b, whereby the vertical inner diameter is reduced.
[0022]
In the present embodiment, since the pipe 15 of the pipe member 13 has an elliptical shape, the inner diameter in the vertical direction is also reduced from above in the vertical direction. In addition, since the ratio between the major axis X and the minor axis Y of the elliptical conduit 15 is ２, the inner diameter in the vertical direction is changed at a ratio of 1１ ／.
[0023]
Next, the operation of the L-valve type loop seal 9 of this embodiment will be described. When adjusting the inner diameter of the horizontal pipe 11, the fastening means 19 is removed and the pipe side flange 16 is connected to the pipe end side flange 17. The pipe member 13 is rotated around the horizontal axis of the horizontal pipe 11 in the range of 0 ° to 90 ° while being shifted in the circumferential direction, and the position of the elliptical pipe 15 with respect to the circular pipe 14 is changed. In this way, the vertical inner diameter of the horizontal pipe 11 can be enlarged or reduced.
[0024]
When the vertical inner diameter of the horizontal pipe 11 is changed by the pipe member 13 in this manner, the apparent horizontal length of the horizontal pipe 11 can be extended by reducing the inner diameter, that is, for example, the horizontal length When the dimension is twice the inside diameter D of the pipe ends 11a and 11b, the vertical dimension is set to, for example, the minor axis (Y = D / 2) of the elliptical pipe 15 so that the horizontal length is reduced. The dimension can be made twice or more the inner diameter dimension, so that the fluid medium is appropriately retained in the horizontal pipe 11 and the fluid medium is stored in the L-valve loop seal 9 at a constant height. Becomes possible.
[0025]
In particular, changing the inner diameter in the vertical direction with respect to the fluid medium which is going to move to the return pipe 10 with the action of collapsing in the direction of gravity is more effective than changing the inner diameter in the horizontal direction. The outflow can be effectively suppressed, the effect of reducing the inner diameter of the horizontal pipe 11 can be further increased, and the fluid medium can appropriately stay in the horizontal pipe 11.
[0026]
Accordingly, the sealing function of the L-valve type loop seal 9 can be properly secured without extending the length of the horizontal pipe 11 and thus without increasing the size of the circulating fluidized bed incinerator 1, and the incinerator 1 stable operation can be guaranteed.
[0027]
Further, since the vertical inner diameter is reduced at least vertically upward from the lower part in the vertical direction by the elliptical pipe 15, when the vertical inner diameter of the horizontal pipe 11 is reduced, the downcomer side pipe end 11a The inner bottom surface of the elliptical pipe 15 of the pipe member 13 rises with respect to the circular pipe 14 of, so that the flow medium from the bottom side of the downcomer 8 is partially blocked, thereby Can be further suppressed, and the L-valve loop seal 9 can more reliably hold the flowing medium.
[0028]
Further, the ratio of the major axis X to the minor axis Y of the elliptical conduit 15 is set to 、, and the ratio of the vertical inner diameter by rotating the pipe member 13 is changed between 1１〜. Therefore, even with the minimum size, it is possible to prevent the horizontal pipe 11 from being blocked by the flowing medium. When the horizontal length of the horizontal pipe 11 composed of both pipe ends 11a and 11b and the pipe member 13 of this embodiment is equivalent to the conventional length (L / D = 2), the minor diameter Y is in the horizontal direction. When the elliptical pipe 15 is rotated in the above manner, the apparent length L in the horizontal direction of the horizontal pipe 11 can be apparently increased to four times the inner diameter dimension in the vertical direction (L / Y = 4). The flowing medium can be held by the L-valve loop seal 9.
[0029]
If the pipe member 13 according to the present embodiment is adopted, the inner diameter of the horizontal pipe 11 in the vertical direction can be extremely simply controlled by simply rotating the pipe member 13 and changing the direction of the internal elliptical pipe 15. Can be changed to be freely expandable and contractible, and the structure is simple and the adjustment operability is good. In the above-described embodiment, the pipe-side flange 16 is shifted at every pitch of the bolt hole 18. However, the bolt hole 18 is formed as a long hole so that it can be shifted continuously. Of course, it is good.
[0030]
3 and 4 show modifications of the tube diameter adjusting means of the above embodiment. The inner diameter of the horizontal pipe 11 in the vertical direction may be changed so as to be freely expandable and contractable, or at least the inner diameter in the vertical direction may be reduced from vertically lower to upper, and the ratio of the inner diameter in the vertical direction may be 1 to 1/2. For example, in place of the rotatable piping member 13, a vertically sliding piping member 13 can be employed.
[0031]
That is, slide plates 20 are provided at both ends of the pipe member 13, and guide plates 21 for guiding the slide plate 20 in the vertical direction are provided at the ends of the respective pipe ends 11 a and 11 b. The slide plate 20 is slid to be fixed to the guide plate 21 at an appropriate height. In the illustrated example, the pipe member 13 having the circular pipe 22 is shown, but the pipe may be elliptical. Even in such a modified example, it is needless to say that the same operation and effect as the above embodiment can be obtained.
[0032]
【The invention's effect】
In short, in the L-valve loop seal of the circulating fluidized bed incinerator according to the present invention, stable operation can be guaranteed without increasing the size of the incinerator.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a horizontal pipe showing a preferred embodiment of an L-valve type loop seal of a circulating fluidized bed incinerator according to the present invention.
FIG. 2 is a sectional view taken along line AA in FIG.
FIG. 3 is a side sectional view of a horizontal pipe showing another embodiment of the L-valve type loop seal of the circulating fluidized bed incinerator according to the present invention.
FIG. 4 is a sectional view taken along line BB in FIG.
FIG. 5 is a schematic side sectional view showing a general circulating fluidized bed incinerator.
FIG. 6 is a side sectional view showing a conventional L-valve type loop seal.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Circulating fluidized bed incinerator 2 Riser 5 Fluidized bed 7 Cyclone 8 Downcomer 8a Start-up part 9 L-valve type loop seal 11 Horizontal pipe 13 Piping member 15 Elliptical pipe F Fluid medium

Claims (4)

The L-shape is formed in an L-shape from a hollow rising portion at the bottom of the downcomer to a horizontal pipe connected to the downcomer. In an L valve type loop seal of a circulating fluidized bed incinerator for sealing between a cyclone,
An L-valve type loop seal for a circulating fluidized bed incinerator, comprising a pipe diameter adjusting means for changing the inner diameter of the horizontal pipe in the vertical direction so as to be scalable. The L-valve type loop seal of a circulating fluidized bed incinerator according to claim 1, wherein the pipe diameter adjusting means reduces at least a vertical inner diameter dimension from a vertically lower portion to an upper portion. The L-valve type loop seal for a circulating fluidized bed incinerator according to claim 1 or 2, wherein the pipe diameter adjusting means changes a vertical inner diameter ratio between 1 and 1/2. The pipe diameter adjusting means is a pipe member having an elliptical pipe formed therein and rotatable around a horizontal axis of the horizontal pipe. L-valve loop seal of a circulating fluidized bed incinerator.

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