KR101798927B1 - feed tube structure for thermal power plant - Google Patents

Abstract

The present invention relates to a transfer tube structure for a thermoelectric power plant, which is installed in a first transfer path connected from a pulverizing mill to a boiler and a fly ash storage tank or a second transfer path connected from a desulfurization facility treating combustion gas of the boiler to a slurry storage tank. The transfer tube structure for the thermoelectric power plant comprises: a unit inner tube formed of a ceramic material having a hollow in which fluid flows, wherein the unit inner tube is formed to be connected to each other in a longitudinal direction; and an outer tube extended by being formed on an outer side of the unit inner tube to enclose the unit inner tube. The unit inner tubes are connected and separated from each other by being inserted and rotated with each other. According to the present invention, the transfer tube structure for the thermoelectric power plant is able to easily be installed as the unit inner tube of a container structure is able to be assembled by rotating and being connected with each other. The transfer tube structure for the thermoelectric power plant is able to improve a performance of shock absorbance by an attached tube inserted between the outer tube and the unit inner tube.

Description

Technical Field [0001] The present invention relates to a feed tube structure for a thermal power plant,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer tube structure for a thermal power plant, and more particularly, to a transfer tube structure for a thermal power plant which can improve durability and is easy to install and repair.

The coal-fired thermal power plant uses pulverized coal, which is finely pulverized coal, to be supplied through the transfer pipe and burned in the boiler. The water in the water pipe that is piped in the boiler is vaporized to rotate by rotating the turbine. .

In addition, the fly ash burnt in the boiler is dropped into the furnace by its own weight, and is transported to the recovery plant through the transfer pipe in the form of slurry, or mixed with the combustion gas and collected separately through the electrostatic precipitator, desulfurization and denitrification equipment.

In this thermal power plant, the conveyance path from the differentiator to the boiler and the conveyance path for discharging the fly ash and desulfurization slurry have a structure in which a linear conveyance pipe and a curved type or elbow type conveyance pipe are mutually combined.

In addition, the metal material conveying pipe installed on the conveyance path from the differentiator to the boiler, the conveyance path from the boiler to the recovery facility, and the conveyance path from the desulfurization facility to the slurry reservoir, is rapidly worn due to impact with pulverized coal or coal by- If the impact is large, cracking occurs. In particular, if the transferring material is leaked out due to the breakage of the conveying pipe, damage to other facilities and environmental pollution occur.

In order to overcome such a problem, a method in which a ceramic liner formed of a ceramic material such as alumina, which has little wear on a thermal shock and a particle collision, is adhered with a ceramic adhesive and used as a transfer pipe in a housing of a metal material, Patent No. 10-0711295 and the like.

However, such a structure can alleviate the wear progress rate by applying the ceramic linening, but it has a disadvantage that the breakage due to the impact can not be improved.

In addition, in the case of attaching a piece of ceramic line-ning in the housing, there is a disadvantage that the gap is easily removed by the gap between the ceramic lines and the manufacturing process is complicated.

It is an object of the present invention to provide a transfer tube structure for a thermal power plant which is easy to assemble according to a required transfer path.

Another object of the present invention is to provide a transfer tube structure for a thermal power plant capable of reducing impact and enhancing durability.

In order to achieve the above object, a transfer tube structure for a thermal power plant according to the present invention comprises a first transfer path from a differentiator to a boiler and a fly ash reservoir, or a second transfer path from a desulfurization facility for processing a combustion gas of the boiler to a slurry reservoir A unit internal pipe formed of a ceramic material and having a hollow through which fluid is moved and formed so as to be mutually connectable along the longitudinal direction; The unit inner tubes are formed so as to surround the unit inner tube and extend to the outside of the unit inner tubes, and the unit inner tubes are formed to be mutually coupled and separated by mutual fitting rotation.

Preferably, the unit inner tube includes a main body portion formed in a cylindrical shape; And an inner coupling protrusion protruding from the one end of the main body part and having an inner diameter larger than that of the main body part and extending in a direction away from one end of the main body part, A first engaging portion formed at a position spaced apart from the first engaging portion; An inner coupling protrusion protruding from an outer circumferential surface of the main body portion and having an outer diameter smaller than that of the main body portion so as to be able to enter the inner side of the first coupling portion of the inner unit tube, And a second engaging portion formed at a position spaced apart from the other end of the inner tube and entering the first engaging portion of the other inner tube and entering and interfitting between the inner engaging projection and the one end of the main body portion when rotated do.

The unit inner tube is inserted between the outer tube and the unit inner tube to support the outer tube and the unit inner tube in close contact with each other. The inner tube is made of a rubber material having elasticity and is formed to protrude from the outer circumferential surface, And a contact tube having a protrusion formed thereon.

According to another aspect of the present invention, the outer tube includes first and second fixing tube portions spaced from each other and formed of a metallic material; An extension pipe portion coupled between the first and second fixed pipe portions and capable of adjusting an extension length thereof; And a length adjuster coupled between the first fixing tube portion and the second fixing tube portion to adjust an extension length of the extension tube portion.

In addition, an inspection window formed so as to penetrate from the outer surface to the unit inner pipe so as to be used for checking the degree of abrasion with respect to the progress of use of the unit inner tube is provided, and a cover And; And a ceramic test piece joined to the cover piece through a relay member so as to be disposed in the inspection window with a thickness corresponding to the inspection window of the unit inner pipe in a state where the cover piece is coupled to the outside of the outer casing.

Preferably, at least one air injection tube communicating from the outside of the outer tube to the inside of the unit inner tube and capable of injecting air obliquely.

More preferably, the unit inner pipe comprises 92 to 96% by weight of Al ₂ O ₃ , 2 to 4% by weight of ZrO ₂ , Y ₂ O ₃ 1 to 2 wt%, TiO ₂ 0.5 to 1 wt%, and Li ₂ O 0.5 to 1 wt%.

According to the transfer pipe structure for a thermal power plant according to the present invention, since the unit inner pipe having a cylindrical structure can be assembled by mutual rotational coupling, the facility is easy, and the impact absorbing performance is improved by the tightly fitting tube inserted between the outer pipe and the unit inner pipe It offers the advantage of being able to.

1 is a schematic view of a thermal power plant to which a transfer tube structure according to the present invention is applied,
FIG. 2 is a partially exploded cross-sectional view illustrating the transfer tube structure of FIG. 1,
3 is a perspective view for explaining a coupling structure for the unit inner pipe of FIG. 2,
FIG. 4 is a partially cutaway perspective view for explaining a close contact support structure of the tightening tube of FIG. 2,
Fig. 5 is a perspective view for explaining the external length adjusting structure of Fig. 2,
6 is a perspective view showing a length adjusting structure of an outer tube according to another embodiment of the present invention,
FIG. 7 is a partial cutaway perspective view showing an inspection window applied to the transfer tube structure of FIG. 1 and an element mounted on the inspection window,
8 is a cross-sectional view illustrating a transfer tube structure according to another embodiment of the present invention,
Fig. 9 is a longitudinal sectional view of a portion where the air injection tube of Fig. 8 is formed,
FIG. 10 is a view showing an assembly structure according to another embodiment of the unit inner pipe of FIG. 2. FIG.

Hereinafter, a transfer tube structure for a thermal power plant according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic view of a thermal power plant to which a transfer tube structure according to the present invention is applied.

Referring to FIG. 1, a thermal power plant includes a differentiator 20, a boiler 30, a coal fly ash storage tank 40, and a desulfurization facility 50.

The differentiator 20 crushes the coal supplied from the coal supply unit 10 supplying coal to the finely pulverized coal and supplies the pulverized coal to the boiler 400 through the transfer tube structure 100.

The coal flyash storage tank 40 is installed so as to collect coal fly ashes fallen by self weight after carbonization from the pulverized coal burned in the boiler 30 from the transfer pipe structural body 100 connected to the lower part of the boiler 400.

The desulfurization facility 50 removes oil residues contained in the combustion gas discharged from the boiler 30. The desulfurization slurry produced in the desulfurization process is introduced into the slurry reservoir 60 ).

Here, the desulfurization slurry is gypsum (CaSO ₄ 2H ₂ O), which is the final by-product.

This thermal power plant has a first feed path leading from the differentiator 20 to the boiler 30 and the flyash storage tank 40 and a second feed path leading from the desulfurization facility 50 to the slurry reservoir 60, The transfer tube structure 100 is provided on the second transfer path.

The transfer tube structure 100 will be described with reference to Fig.

The transfer tube structure 100 includes an unit inner pipe 110, a contact tube 130, and an outer pipe 150.

The unit inner pipe 110 is formed of a ceramic material and has a hollow 115 through which the fluid is moved, and is formed to be mutually connectable along the longitudinal direction.

That is, the unit inner pipes 110 are formed so as to be mutually coupled and separated by mutual fitting rotation, and will be described with reference to FIG.

The unit inner pipe 110 is divided into a main body portion 111, a first engaging portion 112 and a second engaging portion 113 for convenience of explanation.

The main body portion 111 is a cylindrical formed portion having a hollow 115.

The first engaging portion 112 has an inner diameter that is larger than an inner diameter of the main body portion 111 at one end 111a of the main body portion 111 and extends in the longitudinal direction from one end 111a of the main body portion 111 As shown in Fig.

The outer diameter of the first engagement portion 112 has the same outer diameter as the outer diameter of the main body portion 111.

An inner engaging projection 116 protrudes from the inner circumferential surface of the first engaging portion 112 so as to be spaced apart from each other along the inner circumferential direction.

The inner engagement protrusions 116 are formed at a position spaced apart from one end 111a of the main body part 115 and have a predetermined length along the circumferential direction in the form of a rectangular band.

The second coupling portion 113 is formed to have an outer diameter smaller than that of the main body portion 111 so as to be able to enter the inner side of the first coupling portion 112 of the other inner tube 110 at the other end 111b of the main body portion 111. [ Which is formed to extend along the longitudinal direction.

The outer circumferential surfaces of the second engaging portions 113 are formed with outer engaging protrusions 117 protruding from each other.

The outer coupling protrusions 117 are formed to have a predetermined length along the circumferential direction in the form of a rectangular band at a position apart from the other end 111b of the main body portion 111. [

The distance between the outer coupling projections 117 is applied to the inner coupling projections 116 at a distance that allows the inner coupling projections 116 to enter into the first coupling portion 112 of the inner unit tube 110, And one end 111a of the main body part 111, and is fitted and fitted.

That is, when the unit inner tube 110 at the tip end in FIG. 3 is to be coupled to the unit inner tube 110 at the rear end, the outer coupling protrusions 117 of the unit inner tube 110 at the tip end of the unit inner pipe 110 at the rear end The inner engaging projections 116 and the inner engaging projections 116 formed in the first engaging portion 112 are aligned so as to enter into the X direction and then rotated in the Y direction, The outer engaging protrusions 117 are fitted to each other so as to face each other and are not separated in the longitudinal direction.

The unit inner pipe 110 may be formed in a linear cylindrical shape as shown in FIG. 3 when the flow path is a linear section, and may have a curvature according to a curved section when the flow path is a curved section. Unit inner pipe 110 adjacent to each other by the first and second engaging portions 112 and 113. [

If the diameter of the unit inner pipe 110 is very large, it is also possible to apply a plurality of split pieces 110a, which are divided along the circumferential direction, as shown in FIG.

In this case, a divot tail groove 110b is formed on one side and a dovetail projection 110c is fitted on the other side so as to be coupled to each other by sliding coupling along the longitudinal direction. .

Also, the unit internal pipe 110 is alumina (Al ₂ O ₃₎ 92 to 96% by weight of zirconia (ZrO ₂₎ 2 to 4% by weight, yttrium (Y ₂ O ₃₎ 1 to 2% by weight, titanium oxide (TiO ₂ ) 0.5 to 1% by weight, and lithium oxide (Li ₂ O) 0.5 to 1% by weight.

When the content of alumina (Al ₂ O ₃ ) is less than 92% by weight, the density, hardness and strength are lowered and the abrasion resistance is lowered. Even if the content exceeds 96% by weight, the increase in properties due to high purity is insignificant, It is difficult to apply 92 to 96% by weight.

Zirconia (ZrO ₂ ) can inhibit shrinkage and inhibit the volume change of the inner tube due to rapid thermal changes during temperature rise and cooling.

If the amount of zirconia (ZrO ₂ ) is less than 2% by weight, mechanical strength is not expected to be improved. If the amount of zirconia (ZrO ₂ ) is more than 4% by weight, the content of alumina is lowered to affect abrasion resistance.

Yttrium (Y ₂ O ₃ ) Acts on microcracks to increase brittleness and to mitigate damage caused by impact.

Yttrium (Y ₂ O ₃ ) Is less than 1% by weight, microcracks associated with the brittleness in the ceramic are not removed, and a content exceeding 2% by weight does not exceed the cracking removal limit.

When titanium oxide (TiO ₂ ) is added in an amount of 0.5 to 1 wt%, it contributes to stabilization of high-temperature plasticity and suppresses thermal expansion, thereby reducing curvature shape deformation.

When 0.5 to 1% by weight of lithium oxide (Li ₂ O) is added, cracking due to thermal expansion is suppressed, thereby improving the production speed by shortening the cooling rate and improving the thermal shock resistance of the unit inner pipe 110 to be manufactured.

In addition, the unit inner pipe is formed by compressing and molding alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), yttrium, titanium oxide, and lithium oxide having the above-described composition ratios through a molding die, Followed by firing.

The compression molding process is applied with a pressing force of 15,000 kg / cm ² for 5 minutes.

In addition, the firing process may be performed by raising the temperature to 1600 占 폚 at a heating rate of 10 占 폚 / min, and maintaining the isothermal state for 60 minutes when the target temperature is reached 1600 占 폚.

The unit inner tube 110 formed of such a ceramic composition is advantageous in that the shrinkage in the firing process is suppressed and can be manufactured without a large deviation in a desired shape.

The adhesion tube 130 is interposed between the outer tube 150 and the unit inner tube 110 to be described later and serves to support the outer tube 150 and the unit inner tube 110 in close contact with each other.

The contact tube 130 is formed of a stretchable rubber material such as natural rubber, synthetic rubber, or silicone rubber that can be elastically deformed.

The plate-shaped part 132 is formed in the shape of a strip in the form of a plate and spirally wound on the outer side of the unit inner tube 110 to enclose the outer side of the unit inner tube in the form of a tubular tube. And are formed as closely spaced apart projections 135 in the radial direction and the longitudinal direction.

The contact protrusions 135 protruded from the outer circumferential surface of the plate-shaped portion 132 are formed to be deformable by close contact with the outer tube 150.

That is, the protruding length of the contact protrusion 135 protruding from the plate-like portion 132 is formed to be slightly longer than the distance between the plate-like portion 132 and the outer tube 150. In this case, when the tight fitting tube 130 coated on the outer side of the unit inner tube 110 is inserted into the outer tube 150, the tight fitting protrusion 135 is compressively deformed corresponding to the distance from the outer tube 150, ) Can be increased.

Such a tightening tube 130 may be spirally wrapped around the unit inner tube 110.

The outer tube 150 is coupled to the inner tube 110 in a mutually longitudinal direction and is formed so as to surround the inner tube 110 outside the inner tubes 110 covered with the close tube 130.

The outer tube 150 functions to stably support the unit inner tube 110 through the close-coupled tube 130 and may be formed of a metal material, for example, a steel material.

Preferably, the outer tube 150 is configured such that the length of the outer tube 150 can be adjusted so that the outer tube 150 can be finely processed according to the length of the tube structure 100, and an example will be described with reference to FIG.

The outer tube 150 is disposed between the first and second fixing tube portions 150a and 150b formed of a metal material and is coupled between the first and second fixing tube portions 150a and 150b, And a length adjusting unit 160 which is coupled between the first fixing pipe portion 150a and the second fixing pipe portion 150b and adjusts an extension length of the extension pipe portion have.

The expansion and contraction tube portion 150c is formed in the form of a corrugated tube having a curved shape, and a metal material or a synthetic resin material can be applied because the length can be expanded and contracted.

The expansion and contraction tube portion 150c and the first and second fixing tube portions 150a and 150b may be joined by various methods such as welding, joining, or flange coupling.

In the illustrated example, a structure is employed in which the expansion and contraction tube portion 150c of the metal material is welded to the first and second fixing tube portions 150a and 150b.

The length adjusting unit 160 is adjustable in length by a coupling bracket 162, a spacing distance adjusting bolt 165, and a spacing distance adjusting nut 167.

The coupling bracket 162 has a horizontal portion 162a extending in the horizontal direction and a vertical portion 162b extending vertically at one end of the horizontal portion 162a and a through hole is formed in the vertical portion 162b And is formed in an "a" shape.

The coupling bracket 162 may be formed such that the horizontal portion 162a is disposed on the first and second fixing pipe portions 150a and 150b and the vertical portion 162b is extended in the direction in which the outer diameter is expanded.

The coupling brackets 162 are spaced from each other along the circumferential direction of the first and second fixing pipe portions 150a and 150b.

The spacing distance adjusting bolt 165 is inserted through a through hole formed in a coupling bracket 162 disposed opposite to the first and second fixing pipe portions 150a and 150b.

The spacing distance adjusting nut 167 is screwed to the thread of the spacing distance adjusting bolt 165 to adjust and fix the spacing distance.

Alternatively, the length adjusting portion may be formed in a flange structure, and an example thereof will be described with reference to FIG.

The length adjusting unit 260 adjusts the distance between the first and second fixing pipe portions 150a and 150b through the first and second flanges 155 and 156 formed along the circumferential direction, And the length can be adjusted by the bolt 165 and the distance adjustment nut 167. [

That is, the first and second fixing pipe portions 150a and 150b are provided with first and second circular flanges 155 and 156 formed along the circumferential direction and extending in the outer diameter direction, A plurality of through holes into which the distance adjusting bolt 165 can be inserted are formed.

The spacing distance adjusting bolt 165 is inserted through the through holes formed in the mutually facing surfaces of the first and second flanges 155 and 156 so as to be spaced apart in the circumferential direction. Is screwed to the screw thread of the spacing distance adjusting bolt 165 so that the spacing distance can be adjusted.

In the illustrated example, the expansion and contraction tube portion 150c is applied with a structure having third and fourth flanges 157 and 158 formed at both ends in the direction of expanding the outer diameter and formed in a circular plate shape along the circumferential direction.

In this case, the third and fourth flanges 157 and 158 may be formed with through holes at positions corresponding to the through holes formed with the first and second flanges 155 and 156.

The through hole at the position where the fixing bolt 265 is inserted among the first to fourth flanges 155 to 158 is provided with the extension pipe portion 150c and the first and second fixing pipe portions 150a, RTI ID = 0.0 > 267 < / RTI >

On the other hand, there is provided a wear inspection portion for checking the degree of wear of the unit inner pipe 110 with respect to the progress of use, and will be described with reference to FIG.

The inspection window 102 is provided so as to pass from the outer surface 150 of the transfer tube structure 100 to the unit inner pipe 110.

The inspection window 102 is formed in a tapered shape whose inner diameter progressively decreases along the direction from the outer tube 150 to the unit inner tube 110.

The abrasion testing unit 170 includes a lid piece 172, a relay member 174, and a ceramic test piece 110e.

The lid piece 172 is formed to have an expanded size larger than the inspection window 102 so as to cover the inspection window outside the outer appearance 150 and the outer appearance 150 is formed in a plate shape having an arc curvature close to the outer surface have.

The lid piece 172 is joined to and separated from the outer lid 150 in such a manner that the fixing screw 178 applied as the engaging member is inserted into the lid 150 through the lid piece 172. [

The relay member 174 is a portion that is joined to the inner surface of the lid piece 172 at one end and protrudes from the outer tube by an entry depth corresponding to the contact tube 130.

The relay member 174 may be formed of various materials such as the same material as the cover piece 172, the same material as the contact member, or a ceramic adhesive.

The ceramic inspecting piece 110e is disposed in the inspection window 102 so as to be disposed in the inspection window 102 with a thickness corresponding to the inspection window 102 of the unit inner pipe 110 in a state where the cover piece 172 is coupled to the outside of the outer pipe 150 And is coupled to the lower portion of the member 174.

The ceramic inspecting piece 110e is preferably formed of the same material and the same thickness as the unit inner pipe 110.

The abrasion testing unit 170 determines the degree of abrasion by separating the lid piece 172 from the outer tube 150 at each abrasion inspection period or at an appropriate time and measuring the abrasion state of the ceramic test piece 110e through the naked eye or through the tool , So that the maintenance plan can be stably established.

On the other hand, a bending abrasion-suppressing portion capable of restraining the abrasion by adjusting the flow of the transferring material in the bending path portion of the transfer tube structure 110 may be provided, and an example thereof will be described with reference to Figs. 8 and 9. Fig.

Referring to FIGS. 8 and 9, the bending wear suppression unit 180 includes an air injection pipe 182 and an air supply unit 185.

The air injection pipe 182 communicates with the inside of the unit inner pipe 110 from outside the outer pipe 150, and a plurality of air injection pipes 182 are installed along the circumferential direction so as to inject air at an angle.

Here, the inclined direction of the air injection pipe 182 is determined so that the injected air can be injected obliquely with respect to the conveying direction of the conveying material so that no backward component is generated with respect to the conveying direction of the conveying material.

8, when the transfer material is transferred from the lower side to the upper side in the direction indicated by the arrow with the transfer material being not hacked, the air injection pipe 182 is also located inside the unit inner pipe 110 from the outer side of the outer pipe 150 And is inclined upward toward the center of the unit inner pipe 110 from the lower side.

9, the air injection pipe 182 is formed so as to extend in the direction of extension of the inner peripheral surface of the unit inner pipe 110 so that the injected air can swing in the circumferential direction within the unit inner pipe 110, The unit inner pipe 110 may be inclined in a direction parallel to the tangential direction so as to deviate from the center in the transporting material transfer direction described above.

The installation angle of the air injection pipe 182 and the injection opening may be appropriately adjusted according to the inner diameter, the bending radius, and the like of the unit inner pipe 110.

The air supplier 185 pumps the outside air to inject air into the air inlet pipe 182.

According to this structure, the air injected through the air injection pipe 182 generates a swirling flow in the bent portion of the unit inner pipe 110, and the conveying direction of the conveyed material in which the swirling flow is concentrated at the bent portion And the wear rate can be suppressed by reducing the collision rate of the curved portion by dispersing.

According to the transfer pipe structure for a thermal power plant described above, since the unit inner pipe of the cylindrical structure can be assembled by mutual rotational coupling, the facility is easy, and the shock absorbing performance is improved by the tight tube inserted between the outer pipe and the inner pipe It offers the advantage of being able to.

100: transfer tube structure 110: unit inner tube
130: Adhesive tube 150: Appearance

Claims (9)

A transfer pipe structure for a thermal power plant installed on a first conveyance path leading from a differentiator to a boiler and a coal fly ash reservoir or on a second conveyance path leading from a desulfurization facility for treating the combustion gas of the boiler to a slurry reservoir,
A unit inner tube formed of a ceramic material and formed with hollows through which fluids are moved and formed so as to be mutually connectable along the longitudinal direction;
An outer tube formed to surround the unit inner tube outside the unit inner tubes; And
A plurality of tight fitting protrusions inserted between the outer tube and the inner tube to support the outer tube and the inner tube in close contact with each other and made of a rubber material having elasticity and protruding from the outer circumference and being deformed by close contact with the outer tube, And a contact tube formed thereon,
Wherein the unit inner tubes are formed to be mutually engaged and separated by mutual fitting rotation. [2] The apparatus according to claim 1, wherein the unit inner tube comprises a main body portion formed in a cylindrical shape;
And an inner coupling protrusion protruding from the one end of the main body part and having an inner diameter larger than that of the main body part and extending in a direction away from one end of the main body part, A first engaging portion formed at a position spaced apart from the first engaging portion;
An inner coupling protrusion protruding from an outer circumferential surface of the main body portion and having an outer diameter smaller than that of the main body portion so as to be able to enter the inner side of the first coupling portion of the inner unit tube, And is inserted into the first engaging portion of the other unit inner tube and can be inserted between the inner engaging projection of the inner unit inner tube and the one end of the main body portion of the inner unit inner tube when rotated, And a second coupling portion formed on the second end of the second coupling portion. delete [2] The apparatus of claim 1, wherein the outer tube comprises first and second fixing tube portions spaced from each other and formed of a metallic material;
An extension pipe portion coupled between the first and second fixed pipe portions and capable of adjusting an extension length thereof;
And a length adjuster coupled between the first fixing pipe portion and the second fixing pipe portion to adjust an extension length of the extension pipe portion. [5] The apparatus of claim 4, wherein the length adjuster includes: a plurality of engaging brackets extending from the first and second fixing tube portions in a direction in which an outer diameter of the first and second fixing tube portions expands, the engaging brackets being spaced apart from each other along a circumferential direction;
A spacing adjusting bolt inserted through a through hole formed in the coupling bracket so as to be opposed to the first and second fixing pipe portions;
And a separation distance adjusting nut screwed to a threaded line of the separation distance adjustment bolt to adjust the separation distance. [5] The apparatus of claim 4, wherein the length adjuster includes: first and second flanges protruding from the first and second fixing pipe portions in a direction in which an outer diameter of the first and second fixing pipe portions expand;
A spacing adjusting bolt inserted through a through hole formed in a circumferential direction on the mutually facing surfaces of the first and second flanges;
And a separation distance adjusting nut screwed to a threaded line of the separation distance adjustment bolt to adjust the separation distance. The apparatus according to claim 4, further comprising an inspection window formed to penetrate from the exterior to the unit inner pipe so as to be used for checking the degree of wear of the unit inner pipe,
A cover piece coupled to the inspection window by an engaging member so as to cover the inspection window;
And a ceramic test piece coupled to the cover piece through a relay member so as to be disposed in the inspection window with a thickness corresponding to the inspection window of the unit inner pipe in a state where the cover piece is coupled to the outside of the outer casing. Transport pipe structure for thermal power plant. [8] The pipe structure for a thermal power plant according to claim 7, further comprising: at least one air injection pipe communicating from the outer side of the outer pipe to the inner side of the unit inner pipe, wherein air is injected obliquely. The method of claim 1, wherein the inner pipe unit is Al ₂ O ₃ 92 to 96% by weight, ZrO ₂ 2 to 4% by weight, Y ₂ O ₃ 1 to 2% by weight of TiO _2, 0.5 to 1% by weight of TiO _{2, and} 0.5 to 1% by weight of Li ₂ O.

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