JP2011141089A - Fluidized bed reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively prevent wear thinning of an upper wall portion in a predetermined section above a lower wall portion while reducing heat transfer obstructive factors. <P>SOLUTION: Particles descending along the upper wall portion A having furnace wall pipes for performing heat exchange are made to come into contact with a band-shaped refractory 7 protruded inwardly in a position of the upper wall portion A separated upwardly from the lower wall portion B and forming a band shape along the circumferential direction of the upper wall portion A, to make the particles flow toward the inner side of a furnace. Thus, contact of the particles with the upper wall portion C below the band-shaped refractory 7 is prevented and wear thinning of the upper wall portion C is prevented. Since the band-shaped refractory 7 is provided in the position of the upper wall portion A separated upwardly from the lower wall portion B to form the band shape, cost reduction is achieved and the heat transfer obstructive factors are reduced, compared to conventional technologies for covering the predetermined section above the lower wall portion with a hardening building-up layer or a protective film layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fluidized bed reactor.

  Conventionally, fluidized bed boilers are known in which fuel and air supplied from the bottom are mixed with a fluidized material and burned while forming a fluidized bed (fluidized bed), and this combustion reaction exchanges heat with water flowing in the furnace wall tube. ing. In this fluidized bed boiler, the inner wall of the lower part of the furnace forming the fluidized bed is made of a refractory material in order to prevent the thickness of the inner wall of the furnace from being worn and thinned by vigorous stirring of the fluidized material and heat. In such a fluidized bed boiler, a fluidized material or the like is disposed between the upper surface of the refractory and a position spaced a predetermined distance upward from the upper surface of the refractory, that is, in a predetermined section (for example, 2 m) above the refractory. Since the particles repeatedly fall down along the furnace wall tube and repeatedly collide with the furnace wall tube, the furnace wall tube of this predetermined section is made of a wear-resistant metal as described in Patent Document 1 below. The hardened layer thus formed is provided by welding, or a protective coating layer made of a wear-resistant metal is provided by welding to improve wear resistance.

JP 2003-50003 A

  However, in the fluidized bed boiler, a hardened layer made of wear-resistant metal is provided by welding over a wide range from the upper surface of the refractory to a predetermined section, or a protective coating layer made of wear-resistant metal is provided. Since it provides by welding, there exists a problem that cost becomes very high. In addition, since the hardfacing layer or the protective coating layer covering the furnace wall tube covers a wide range in this way, there is also a problem that heat transfer for heat exchange is hindered.

  The present invention has been made to solve the above-mentioned problems, including a fluidized bed boiler that can prevent wear thinning of the inner wall of a furnace at low cost while reducing heat transfer inhibition factors. An object is to provide a fluidized bed reactor.

  The fluidized bed reactor according to the present invention is a fluidized bed reactor for conducting a reaction in the reaction chamber while introducing a gas from the lower part of the reaction chamber and flowing solids, and has a furnace wall tube for performing heat exchange. In a fluidized bed reactor comprising an upper wall portion and a lower wall portion having a refractory set below the upper wall portion, the upper wall portion protrudes inward at a position spaced above the lower wall portion. And a belt-like refractory having a belt-like shape along the circumferential direction of the upper wall portion.

  According to such a fluidized bed reactor, the particles descending along the upper wall portion provided with the furnace wall tube for performing heat exchange are located at a position spaced above the lower wall portion in the upper wall portion. It is provided and protrudes inward and comes into contact with a strip-shaped refractory that forms a strip along the circumferential direction of the upper wall portion, and its flow is directed toward the inside of the furnace. For this reason, the contact of the particle | grains with the upper wall part below a strip | belt-shaped refractory material is prevented, and the wear thinning of the said upper wall part can be prevented. Further, as described above, since the belt-like refractory is provided in a belt shape at a position spaced above the lower wall portion in the upper wall portion, the predetermined section above the lower wall portion is hardened or protected. Compared with the prior art covered with a coating layer, the cost is low, heat transfer inhibition factors can be reduced, and heat exchange efficiency can be improved.

  Here, the belt-like refractory has an inclined surface that is located on the inner side of the upper surface and is inclined so as to be lowered toward the inner side. Thus, contact with the upper wall portion below the belt-like refractory is further prevented, and wear thinning of the upper wall portion can be further prevented.

  Moreover, it is preferable that the height H of the strip-shaped refractory satisfies the relationship of 100 mm ≦ H ≦ 300 mm. This is because, when L <100 mm, the belt-like refractory is too short, for example, when it is held by a stud pin, it is difficult to hold by the stud pin, and there is a risk of falling off, and when L> 300 mm This is because the heat transfer inhibition becomes large.

  Moreover, it is preferable that the protrusion length L of the strip-shaped refractory satisfies the relationship of 40 mm ≦ L ≦ 100 mm. This is because when L <40 mm, the belt-like refractory is too thin and, for example, if it is held by a stud pin, it is difficult to hold by the stud pin, and there is a risk of falling off, and the descending particles are strip-like refractory This is because it is easy to come into contact with the lower upper wall portion, and when L> 100 mm, the belt-like refractory is too thick, for example, when it is held by a stud pin, it is too heavy and may fall off. .

  As described above, according to the fluidized bed reactor of the present invention, it is possible to prevent wear thinning of the upper wall portion of the predetermined section above the lower wall portion at a low cost while reducing heat transfer inhibition factors.

1 is a schematic cross-sectional configuration diagram showing a fluidized bed reactor according to an embodiment of the present invention. It is the figure which looked at the principal part of the upper wall part of the fluidized bed reactor shown in FIG. 1 from the furnace inner side with the upper part of the lower wall part. It is the III-III arrow line view of FIG. It is the IV-IV arrow line view of FIG. It is a figure which shows the fluidized bed reactor and cyclone which comprise a rectangular cylinder shape.

  Hereinafter, a preferred embodiment of a fluidized bed reactor according to the present invention will be described with reference to FIGS. FIG. 1 is a schematic sectional view showing a fluidized bed reactor according to an embodiment of the present invention, and FIG. 2 shows a furnace together with the upper part of the lower wall portion of the upper wall portion of the fluidized bed reactor shown in FIG. FIG. 3A is a view taken from the inside, FIG. 3A is a view taken in the direction of arrows III-III in FIG. 2, FIG. 3B is a view in which FIG. 3A is welded, and FIG. FIG. 5 is a view showing a fluidized bed reactor and a cyclone having a rectangular cylindrical shape, in which FIG. 5 (a) is a partially broken side view, and FIG. 5 (b) is FIG. It is a VV arrow line view of (a), and demonstrates a fluidized bed reactor as a circulating fluidized bed (CFB; Circulating FluidizedBed) boiler here.

  As shown in FIG. 1, the circulating fluidized bed boiler 100 has a shape in which the upper and lower ends of a rectangular cylinder are closed, and the lower part thereof narrows in the width direction (left and right direction in FIG. 1) as it goes downward, and the rectangular cylinder becomes smaller. It is made into a shape. In this circulating fluidized bed boiler 100, the inside of the furnace wall 1 that forms a shape in which the upper and lower ends of a rectangular cylinder are closed is a reaction chamber 2, and combustion air is supplied from a plurality of openings 3 provided at the bottom of the reaction chamber 2. In addition to introduction, fuel (solid matter) is introduced from the lower part of the reaction chamber 2 and the combustion reaction is performed in the reaction chamber 2 while flowing the fuel.

  Specifically, the furnace wall 1 of the circulating fluidized bed boiler 100 is, as shown in FIGS. 2 and 4, a water wall tube (furnace wall pipe) 4 arranged in parallel in the furnace wall circumferential direction (left-right direction in the figure). , 4 are connected by flat fins 5 so-called membrane panels. The water wall tube 4 exchanges heat from the combustion reaction in the reaction chamber 2 with water flowing in the water wall tube 4.

  The membrane panel 1 comprising the water wall tubes 4 and the fins 5 and constituting the furnace wall, as shown in FIG. 1, is bent obliquely downward and outward at a position spaced a predetermined distance upward from the bottom. When it is directed outward by a predetermined distance, it is further bent obliquely downward and inward, and a refractory 6 is provided in a recessed portion formed by this bending.

  That is, as shown in FIGS. 1 and 2, the furnace wall has a water wall tube 4 for performing heat exchange, and is set below the upper wall portion A where the membrane panel 1 is exposed and the upper wall portion A. And a lower wall portion B having the refractory 6 and covering the membrane panel 1 with the refractory 6. And the refractory 6 is accommodated in the dent part of the lower wall part B in this way, and the inner wall surface of the upper wall part A and the surface of the refractory 6 of the lower wall part B are substantially flush with each other. It is said that.

  Here, the refractory 6 is a refractory lining such as a ceramic fired product. Further, instead of the water wall tube 4 through which water flows, heat exchange may be performed using a furnace wall tube through which water vapor flows.

  The circulating fluidized bed boiler 100 is provided with a cyclone 11 as shown in FIG. The cyclone 11 introduces the combustion gas and particles generated by the combustion reaction in the reaction chamber 2 through the combustion gas inlet 11 a at the top of the cyclone 11 to separate the particles from the combustion gas, and separates the separated particles from the cyclone 11. It returns to the lower part of the boiler through the lower particle discharge port 11b.

  Here, in this circulating fluidized bed boiler 100, as shown in FIGS. 1 and 2, the upper wall portion particularly extends to a position spaced apart from the upper end of the refractory 6 of the lower wall portion B by a predetermined distance (about 2 m). Since wear thinning becomes prominent, in this embodiment, a strip-like refractory 7 that protrudes inward and forms a strip along the circumferential direction of the upper wall portion A is provided at a position separated by a predetermined distance. Yes.

  This strip-shaped refractory 7 is configured like a shelf extending in a strip shape, and as shown in FIGS. 2 and 3, an upper inclined surface 8 that is located on the inner side of the upper surface and tilts downward toward the inner side. And has a lower inclined surface 9 that is located inside the lower surface and is inclined so as to rise inward, and a surface between the inner ridge line of the upper inclined surface 8 and the inner ridge line of the lower inclined surface 9 is The vertical surface 12 is used. In addition, even if this strip | belt-shaped refractory 7 is provided continuously over the perimeter of the upper wall part A, it may be provided intermittently in the circumferential direction.

  Here, the strip-like refractory 7 is a ceramic fired product. As shown in FIGS. 3 and 4, the ceramic fired product has staggered stud pins 10 (for example, along the axial direction) on the outer peripheral surface of the water wall tube 4 along the axial direction of the water wall tube 4. And form the belt-shaped refractory so as to surround it from the inside while arranging and welding the anchors so that they are spaced apart in the middle, left side, middle, and right side of the outer peripheral surface. It is obtained by pouring a refractory into this formwork, solidifying, releasing, and firing. In addition, a refractory brick etc. can also be used.

  According to the circulating fluidized bed boiler 100 having such a configuration, a combustion reaction is performed in the reaction chamber 2, and heat generated by the combustion reaction is transmitted to the water wall tube 4 to perform heat exchange. Combustion gas generated by the combustion reaction rises from the center side in the furnace with particles, and is discharged to the cyclone 11 at the subsequent stage, and the remaining particles descend along the upper wall portion A.

  The particles descending along the upper wall portion A are provided at positions spaced above the lower wall portion B in the upper wall portion A, protrude inward, and have a band shape along the circumferential direction of the upper wall portion A. It contacts the belt-like refractory 7 formed, and its flow goes to the inside of the furnace. For this reason, the particle | grain contact with the upper wall part C (refer FIG. 1) below the strip | belt-shaped refractory material 7 is prevented, and the wear thinning of the said upper wall part C can be prevented. Further, as described above, the strip-like refractory 7 is provided in a strip shape at a position spaced above the lower wall portion B in the upper wall portion A. Compared with the prior art covered with a layer or a protective coating layer, the cost is low and the heat transfer inhibiting factor can be reduced. That is, wear reduction of the upper wall portion C in the predetermined section above the lower wall portion B can be prevented at low cost while reducing heat transfer inhibition factors.

  In addition, in the present embodiment, the belt-like refractory 7 is a ceramic fired product, a refractory brick, or the like, and therefore, compared to a case where a hardened layer or a protective coating layer is provided as in the prior art. Furthermore, cost reduction is achieved.

  Further, since the belt-like refractory 7 has an upper inclined surface 8 which is located on the inner side of the upper surface and is inclined downward toward the inner side, the inclined surface 8 positively attracts the descending particles. It comes closer to the inside of the furnace, and further contact with the upper wall portion C below the belt-like refractory 7 is further prevented, and wear reduction of the upper wall portion C can be further prevented.

  Here, the height H (see FIG. 3) of the strip-shaped refractory 7 preferably satisfies the relationship of 100 mm ≦ H ≦ 300 mm. This is because when L <100 mm, the belt-like refractory 7 is too short and is held by the stud pin 10, it is difficult to hold by the stud pin 10 and may drop off, and L> 300 mm. This is because the heat transfer inhibition becomes large.

  Moreover, it is preferable that the protrusion length L of the strip-shaped refractory 7 satisfies the relationship of 40 mm ≦ L ≦ 100 mm. This is because when L <40 mm, the belt-like refractory 7 is too thin and is held by the stud pin 10, it is difficult to hold by the stud pin 10, and there is a risk of falling off. It is because it becomes easy to contact the upper wall part C below the thing 7, and when L> 100mm, when the strip-like refractory 7 is too thick and is held by the stud pin 10, there is a possibility of dropping too much. Because.

  Furthermore, as shown in FIG. 3 (b), welding overlay is formed between the upper wall portion F (water wall tube 4 and fin 5; membrane panel) extending from the upper surface of the strip-shaped refractory 7 to a short upper range. 13 is preferably applied. By providing the weld overlay 13 in this manner, when the particles bounce back to the upper wall portion F side on the upper surface of the strip-like refractory 7, the weld overlay 13 is hit, and wear reduction of the upper wall portion F is reduced. Can be prevented.

  Incidentally, as shown in FIG. 5, when two cyclones 11 are respectively attached to both ends (upper and lower ends of FIG. 5B) of the circulating fluidized bed boiler 100 having a rectangular cylindrical shape, The upper part of the cyclone 11 has a combustion gas inlet 11a connected to both ends of the upper part of the rectangular tube, and the lower part of the cyclone 11 has a particle outlet 11b at a position below the combustion gas inlet 11a. In each case, since the particles are returned to both ends of the furnace, wear thinning of the upper wall portion above the particle discharge port 11b on both ends of the furnace becomes remarkable. The belt-like refractory 7 may be provided only above the particle discharge ports 11b on both end sides. Even in such a case, the height L1 of the circulating fluidized bed boiler 100 is about 15 m (for a small size) to about 40 m (for a large size), and the belt-like refractory 7 has a height of L1. Regardless, the upper wall L is provided at a position L2 = about 2 m away from the upper end of the refractory 6 of the lower wall portion B.

  Although the present invention has been specifically described above based on the embodiment, the present invention is not limited to the above embodiment. For example, in the above embodiment, the belt-like refractory 7 is used from the viewpoint of cost reduction. Are fired ceramics, refractory bricks, or the like, but may be weld overlays having substantially the same shape as the strip refractories.

  Moreover, in the said embodiment, although the circulating fluidized bed boiler 100 is made into the rectangular cylinder shape, a cylindrical shape etc. may be sufficient, for example.

  Moreover, in the said embodiment, although application to the circulating fluidized bed boiler 100 is described as being especially suitable, it is applicable also to the fluidized bed boiler which does not circulate, Furthermore, it is not a combustion reaction but is a chemical with heat generation. It can also be applied to a reactor that performs a reaction. In short, a gas (other than air) is introduced from the lower part of the reaction chamber, and the reaction is performed in the reaction chamber while flowing solids (for example, fuel or reaction target). Applicable to fluidized bed reactor.

  DESCRIPTION OF SYMBOLS 1 ... Membrane panel (furnace wall), 2 ... Reaction chamber, 3 ... Opening, 4 ... Water wall tube (furnace wall tube), 5 ... Fin, 6 ... Refractory, 7 ... Strip refractory, 8 ... Strip refractory Upper inclined surface, 9 ... Lower inclined surface of the strip refractory, 10 ... Stud pin, 11 ... Cyclone, 13 ... Welding, 100 ... Circulating fluidized bed boiler (fluidized bed reactor), A ... Upper wall part, B ... Lower wall portion, C: upper wall portion below the strip-shaped refractory, H: height of the strip-shaped refractory, L: protrusion length of the strip-shaped refractory.

Claims (4)

A fluidized bed reactor in which a gas is introduced from the lower part of the reaction chamber to cause a reaction in the reaction chamber while flowing solids, and an upper wall portion having a furnace wall tube for heat exchange, and the upper wall A fluidized bed reactor comprising a lower wall portion set under the portion and having a refractory,
A fluidized bed reactor comprising a strip-shaped refractory that protrudes inward and forms a strip along the circumferential direction of the upper wall portion at a position spaced apart from the lower wall portion in the upper wall portion .   The fluidized bed reactor according to claim 1, wherein the belt-like refractory has an inclined surface that is located on the inner side of the upper surface and is inclined downward.   3. The fluidized bed reactor according to claim 1, wherein a height H of the belt-like refractory satisfies a relationship of 100 mm ≦ H ≦ 300 mm.   The fluidized bed reactor according to any one of claims 1 to 3, wherein the protrusion length L of the strip refractory satisfies a relationship of 40 mm ≤ L ≤ 100 mm.

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