JP6458930B2 - Sludge incinerator repair method - Google Patents

Description

  The present invention relates to a method for repairing a sludge incinerator.

  For example, in a sewage treatment plant, in order to burn sewage sludge, a sludge incinerator such as a fluidized bed incinerator is provided to effectively use the sludge. The fluidized bed incinerator includes a cylindrical furnace body having a fluidized bed portion using sand as a fluidized medium and a combustion chamber (freeboard portion). The fluidized bed incinerator is an incinerator that supplies dehydrated cake (including dried cake) to the fluidized bed portion and instantaneously incinerate the dehydrated cake at a high temperature (for example, 800 ° C.).

The fluidized bed portion is a portion that performs gasification combustion by bringing the dehydrated cake into contact with a fluid medium (primary combustion), and the combustion chamber is a portion that burns a gas containing unburned components (secondary combustion).
The furnace body is formed of a steel casing, and the inner peripheral surface of the steel casing is lined with a refractory material and a heat insulating material that are linings in the furnace.

  Since a steel casing corrodes a steel casing by exhaust gas turning to the back side of a refractory material by use over time, it is common to repair in about 10 years. As a conventional repair method, a method of exchanging the entire furnace main body, a method of maintaining a strength by welding a contact plate from the outside to a corroded steel casing, and the like are known.

  As a method for repairing a liner of a gas turbine combustor, Patent Document 1 discloses that a liner is divided into a plurality of members made of a cylinder in an axial direction, and each member is joined to form a liner. A repair method is described in which only the damaged part is replaced.

Japanese Patent No. 3915423

By the way, among the conventional repair methods described above, the method of exchanging the entire furnace body requires the installation of a new incinerator after performing foundation work after dismantling, which leads to a long construction period and high costs. There is.
In addition, the method of maintaining the strength by welding a contact plate to the corroded steel casing from the outside can prevent buckling of the steel casing, but the thickness corrosion of the existing casing proceeds. Moreover, since the intensity | strength of the caster anchor which supports a refractory material, the brick receiving metal object which supports the load of a brick, etc. cannot be hold | maintained, it is not a permanent measure.

  Moreover, since the liner of a combustor is divided | segmented into the member which consists of a some cylinder, the repair method described in patent document 1 has the subject that repair work will be obstructed when work space is restrict | limited.

  It is an object of the present invention to provide a method for repairing a sludge incinerator that can be repaired in a short construction period and at low cost, and that can be repaired even when the work space is limited.

According to the first aspect of the present invention, a method for repairing a sludge incinerator includes a saddle part forming step of forming a plurality of saddle parts in a cylindrical furnace body, and the saddle part is supported by a jack installed on a beam. And a removing step of removing the cut portion by cutting the furnace body into a plurality of portions in the axial direction below the saddle portion, and removing the cut portion as a whole, forming a cylindrical shape corresponding to the cut portion. A replacement furnace body forming step for forming a replacement furnace body divided into a plurality in the circumferential direction, and the furnace body formed by removing the cutting portion while supporting the saddle portion with the jack. A flange portion forming step of forming a first flange portion that protrudes in a flange shape from the edge portion toward the outer peripheral side in the radial direction and has a length in the radial direction that is shorter than the saddle portion and does not contact the jack at the edge portion; The replacement furnace body is the furnace body. Wherein the assembling step of assembling together the cylindrical and carried respectively to the cutting position, while supporting the saddle portion by the jack, projecting like a flange in the radial direction outer peripheral side of the edge of the replacement furnace body, the radial And a joining step of joining the first flange part and the second flange part having a length in the direction similar to the first flange part .

According to such a configuration, even when the furnace body is corroded due to aging, the furnace body can be repaired at a short construction period and at low cost. Even when the furnace body is deformed, the deformation of the furnace body can be absorbed by joining the flange portions. Further, since the replacement furnace body is divided in the circumferential direction, the replacement furnace body can be carried in and assembled even when the work space is limited.
Moreover, a removal process can be performed more safely by having the support process which supports a saddle part with the jack installed in the beam.
In addition, by forming a plurality of saddle portions on the cylindrical furnace body, the furnace body at a position above the cutting location can be supported in the supporting step even when the first flange portion is provided. That is, for example, when the furnace body is supported using a jack, the support member can be supported even when the jack is installed on the radially outer side of the flange portion.

  In the above-described method for repairing a sludge incinerator, the replacement furnace bodies may be joined to each other by side flange portions that border a cross section in the longitudinal direction.

  According to such a configuration, it is possible to easily assemble the divided replacement furnace body. That is, even when the replacement furnace body is deformed, the deformation of the replacement furnace body can be absorbed by joining the side flange portions. Further, the strength of the replacement furnace body can be improved.

  According to the present invention, repair can be performed at a short construction period and at low cost, and repair can be performed even when the work space is limited.

It is a sectional side view explaining the outline of the fluidized-bed incinerator to which the repair method of the sludge incinerator of embodiment of this invention is applied. It is an enlarged view of the A section of Drawing 1, and is a sectional view explaining details of a furnace body. It is the schematic explaining the saddle part formation process of the repair method of the sludge incinerator of embodiment of this invention, a support process, and a removal process. It is the schematic explaining the flange part formation process of the repair method of the sludge incinerator of embodiment of this invention. It is a perspective view of the furnace for exchange of the embodiment of the present invention. It is a perspective view of the division | segmentation furnace body divided | segmented of embodiment of this invention. It is the schematic explaining the joining process of the repair method of the sludge incinerator of embodiment of this invention.

Hereinafter, the repair method of the sludge incinerator of embodiment of this invention is demonstrated in detail with reference to drawings.
FIG. 1 is a side sectional view for explaining the outline of a fluidized bed incinerator 1 to which a method for repairing a sludge incinerator according to an embodiment of the present invention is applied. The fluidized bed incinerator 1 is a sludge incinerator for burning dewatered cake that has been concentrated and dewatered in a facility such as a sewage treatment plant. As shown in FIG. 1, the fluidized bed incinerator 1 has a cylindrical furnace body 2 having a wind box 3 below.

  The furnace main body 2 of the fluidized bed incinerator 1 has a cylindrical shape whose central axis extends along the vertical direction, and a dispersion plate 4 that divides the interior of the furnace main body 2 in the vertical direction is provided at the lower part. The wind box 3 is a space below the dispersion plate 4, and primary air A <b> 1 is supplied to the wind box 3 from a blower (not shown) through the primary air inlet 6.

Above the dispersion plate 4, fluid sand 8 is deposited as a fluid medium to form a sand layer portion 7. Above the sand layer portion 7 is a free board portion 9.
The dehydrated cake is charged into the sand layer portion 7 inside the furnace body 2 through a charging port 10 from a charging machine (not shown).

The free board part 9 of the furnace body 2 can be provided with at least one secondary air inlet 12.
The upper part of the furnace body 2 is narrowed upward so as to have an upward convex conical shape. A discharge port 13 for discharging the exhaust gas E is provided at the top of the furnace body 2, that is, at the apex of the conical shape. The exhaust gas E discharged from the discharge port 13 is introduced into an exhaust gas treatment device such as a gas cooling tower or a bag filter, for example.

  In the fluidized bed incinerator 1, the primary air A <b> 1 is introduced into the sand layer portion 7 (hereinafter referred to as the fluidized bed portion) through the dispersion plate 4 and fluidized, and then from the auxiliary fuel inlet (not shown). An auxiliary combustor is added and the fluidized bed is heated to a high temperature. In this state, the dehydrated cake thrown into the fluidized bed part is supported by the primary air A1 in contact with the fluidized sand 8 in the hot fluidized bed part, and is gasified and burned. At this time, the unburned gas generated in the fluidized bed portion is reburned in the free board portion 9 by the secondary air A2.

  The furnace body 2 is a steel casing 15 formed of a steel material such as a general structural rolled steel material, and the inner peripheral surface of the steel casing 15 is lined with a refractory material and a heat insulating material which are furnace linings. Specifically, as shown in FIG. 2, a heat insulating layer 16 is formed on the inner peripheral surface of a steel casing 15 constituting the furnace body 2 by heat insulating castable. A fireproof layer 17 is formed on the inner peripheral surface of the heat insulating layer 16 by fireproof castable.

  Here, in the fluidized bed incinerator 1, the furnace main body 2 is corroded as the exhaust gas E turns to the back side of the refractory layer 17 by use over time. In particular, the free board portion 9 exposed to the exhaust gas E and the acid gas is easily corroded, and repairs are required in about 10 years at the location. Hereinafter, the repair method of the furnace body 2 will be described in detail.

  The repair method of the furnace body 2 of the present embodiment includes a saddle part forming step for forming a saddle portion 18 (see FIG. 3) in the furnace body 2, a supporting step for supporting the furnace body 2, and a part of the furnace body 2. A removing step for removing, a flange portion forming step for forming the first flange portion 22 (see FIG. 4) in the furnace body 2, a replacement furnace forming step for forming the replacement furnace body 23 (see FIG. 5), An assembling process for assembling the replacement furnace body 23 into an integral cylinder; a first flange portion 22 provided on the outer peripheral surface of the furnace body 2; a second flange portion 25 provided on the outer peripheral surface of the replacement furnace body 23; And a bonding step of bonding.

  In the repair method of the furnace body 2 according to the present embodiment, the upper and lower portions of the portion where defects such as corrosion are confirmed are cut into a ring shape to remove a part of the furnace body 2, and a cutting point C (see FIG. 3). A replacement furnace body 23 which is an alternative to the above is attached to the cut portion C. As a result, the furnace body 2 is repaired without replacing the entire furnace body 2.

Next, each process of the repair method of the furnace main body 2 is demonstrated in detail.
The saddle portion forming step is a step of forming a plurality of saddle portions 18 (support members) in a portion above the portion that becomes the cut portion C in the furnace body 2. As shown in FIG. 3, it is a member that protrudes radially outward from the outer peripheral surface of the furnace body 2. The saddle portion 18 is formed of a steel material, and a plurality of saddle portions 18 are provided in the circumferential direction of the furnace body 2.

The supporting step is a step of supporting a portion above the cutting point C in the furnace body 2 using the saddle portion 18 formed in the saddle portion forming step. As shown in FIG. 3, in the supporting step, the saddle portion 18 is supported using a jack 20 installed on a predetermined beam 19 (supporting structure). Thereby, the furnace main body 2 located above the cutting location C is supported.
The jack 20 is preferably a hydraulic jack. When the vertical distance between the beam 19 and the saddle portion 18 is small, it is preferable to use a jack with a claw. Moreover, when the existing beam 19 is used, it is preferable to reinforce the beam 19 appropriately.

  The removal step is a step of removing a part of the furnace body 2, that is, a cut portion C that is a portion where defects such as corrosion have been confirmed. In the removing step, the furnace body 2 is cut into a ring shape at two axial positions (indicated by reference symbol P), and the cut portion C is removed. The cutting can be performed by, for example, a gas burner. The furnace body 2 above the cutting point C is supported by a saddle portion 18 formed in the saddle portion forming step.

A flange part formation process is a process of forming the 1st flange part 22 in the edge of the furnace main body 2 formed by removing the cutting location C. FIG. The first flange portion 22 is formed so as to protrude like a bowl from the circular edge of the furnace body 2 toward the radially outer peripheral side.
The first flange portion 22 is a plate-like member having a circular outer shape when viewed from the axial direction. The 1st flange part 22 is joined to the edge of the furnace main body 2 by welding, for example.

  Here, the saddle portion 18 formed in the saddle portion forming step protrudes radially outward from the first flange portion 22. That is, the radial length W2 of the saddle portion 18 is longer than the radial width W1 of the first flange portion 22, and the end portion on the radial outer peripheral side of the saddle portion 18 is the radial outer periphery of the first flange portion 22. It protrudes radially outward from the end of the side. Thereby, when supporting the furnace main body 2 using the jack 20, even when the jack 20 is installed in the radial direction outer peripheral side rather than the 1st flange part 22, the saddle part 18 can be supported.

The replacement furnace body forming step is a step of forming a replacement furnace body 23 that has a cylindrical shape corresponding to the cut portion C as a whole and is divided in the circumferential direction. The replacement furnace body 23 is divided into four parts, and is joined so as to form a cylinder by welding, for example, in the assembly process. A division | segmentation location is shown with the code | symbol D of FIG.
First, for example, the replacement furnace body 23 divided into four parts will be described as an integral cylinder. As shown in FIG. 5, the replacement furnace body 23 includes a cylindrical main body portion 24 and second flange portions 25 formed at both end portions in the axial direction of the main body portion 24.

The second flange portion 25 is formed so as to protrude from the circular edge portion of the main body portion 24 in a radial shape on the outer peripheral side in the radial direction. The shape of the 2nd flange part 25 is substantially the same as the 1st flange part 22 formed in the flange part formation process mentioned above.
Similar to the furnace body 2, the replacement furnace body 23 is formed of a steel material, and the inner peripheral surface of the body portion 24 may be lined with a refractory material and a heat insulating material that are linings in the furnace.

Next, the shape of each part of the replacement furnace body 23 divided into four parts will be described.
As shown in FIG. 6, the divided replacement furnace body 26, which is a divided replacement furnace body 23, has a side flange portion 27 that borders a cross section in the longitudinal direction. The side flange portion 27 is formed so as to protrude from the dividing line of the replacement furnace body 23 to the radially outer peripheral side. The side flange portion 27 is a plate-like member having a rectangular outer shape when viewed from the circumferential direction of the replacement furnace body 23. The radial width of the side flange portion 27 is preferably the same size as the flange portions 22 and 25 of the furnace body 2.

In the assembling process, the divided replacement furnace body 26 which is the divided replacement furnace body 23 is carried into the place where the fluidized bed incinerator 1 is installed, and the divided replacement furnace body 26 is formed into an integral cylinder. This is an assembly process.
In the assembly process, the split replacement furnace bodies 26 are joined to each other by, for example, welding using the side flange portions 27. The joined side flange portions 27 are preferably fastened using a fastening member such as a hexagon bolt, for example. By fastening using hexagon bolts, the joining of the side flange portions 27 can be strengthened.

As shown in FIG. 7, the joining step is a step of joining the first flange portion 22 provided on the outer peripheral surface of the furnace body 2 and the second flange portion 25 provided on the outer peripheral surface of the replacement furnace body 23. is there.
Here, the radial widths of the flange portions 22 and 25 are dimensions that allow deformation of the furnace body 2. That is, even when the furnace body 2 is deformed with age, the flange parts 22 and 25 are joined to each other so that the deformation of the furnace body 2 can be absorbed.
The joined flange portions 22 and 25 are preferably fastened using a fastening member such as a hexagon bolt, for example. By fastening using hexagon bolts, the joint between the flange portions 22 and 25 can be strengthened.

  According to the said embodiment, even when the furnace main body 2 is corroded by aged use, the furnace main body 2 can be repaired with a short construction period and low cost. Further, the replacement furnace body 23 is formed of the same steel material as that of the furnace body 2, and the furnace body 2 and the replacement furnace body 23 are joined to each other via the flange portions 22 and 25, thereby the furnace body. The strength after repair of 2 can be made equivalent to that of a new incinerator.

  Further, since the replacement furnace body 23 is divided in the circumferential direction, the replacement furnace body 23 can be carried in and assembled even when the work space is limited.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the support step of the above embodiment, the furnace body 2 located above the cutting point C is supported from below by the jack 20, but the furnace body 2 may be lifted by a crane or the like.
Moreover, in the said embodiment, although the repair of the furnace main body 2 of the fluidized bed incinerator 1 was demonstrated to the example, you may apply the repair method of the sludge incinerator of this embodiment to the repair of a circulation type fluidized furnace.
Moreover, in the said embodiment, although it was set as the structure which removes only the cutting location C of one place, you may implement the repair of several locations simultaneously by removing the cutting location C of several locations.

DESCRIPTION OF SYMBOLS 1 Fluidized bed incinerator 2 Furnace main body 3 Wind box 4 Dispersion plate 6 Primary air inlet 7 Sand layer part 8 Fluid sand 9 Free board part 10 Input port 12 Secondary air inlet 13 Discharge port 15 Steel casing 16 Thermal insulation layer 17 Fireproof Layer 18 Saddle (support member)
DESCRIPTION OF SYMBOLS 19 Beam 20 Jack 22 1st flange part 23 Replacement furnace body 24 Main body part 25 Second flange part 26 Split replacement furnace body 27 Side flange part A1 Primary air C Cutting location E Exhaust gas

Claims (2)

A saddle part forming step of forming a plurality of saddle parts in a cylindrical furnace body;
A supporting step of supporting the saddle portion with a jack installed on the beam;
Below the saddle portion, a removal step of cutting the furnace main body into a plurality of portions in the axial direction and removing the cut portions ,
As a whole, a replacement furnace body forming step for forming a replacement furnace body divided into a plurality of parts in the circumferential direction, which has a cylindrical shape corresponding to the cut portion,
While supporting the saddle portion with the jack, the edge of the furnace body formed by removing the cut portion protrudes in a bowl shape radially outward from the edge, and the radial direction A flange portion forming step of forming a first flange portion whose length is shorter than the saddle portion and does not contact the jack;
An assembly step of bringing the replacement furnace body into the cut portion of the furnace body and assembling it into an integral cylinder;
While supporting the saddle portion with the jack, the flange portion protrudes radially outward from the edge portion of the replacement furnace body , and the length in the radial direction is the same as that of the first flange portion. A joining step of joining the first flange portion ;
Repair method for sludge incinerators.   The method for repairing a sludge incinerator according to claim 1, wherein the replacement furnace bodies are joined to each other by side flange portions that frame a cross section in a longitudinal direction.

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