JP6000795B2 - Fluidized bed combustion furnace - Google Patents

Description

  The present invention relates to a fluidized bed combustion furnace.

  2. Description of the Related Art Conventionally, there is known a fluidized bed furnace in which fuel such as coal is mixed with a fluidized material such as silica sand and the fuel is combusted while forming a fluidized bed (fluidized bed) in which the fluid flows. In this fluidized bed furnace, a thermometer is installed to accurately grasp the temperature of the combustion chamber. This thermometer is arranged so that it passes through the furnace wall forming the combustion chamber and the measurement part is covered with a protective tube made of a material such as stainless steel and protrudes into the furnace.

  Here, in the fluidized bed furnace, since the fluidized material is repeatedly lowered along the furnace wall, the fluidized material contacts (impacts) the protective tube protruding into the furnace, and the protective tube is worn. Then, for example, disconnection or the like occurs due to such wear of the protective tube, and the accurate temperature cannot be grasped. As a result, frequent replacement of the thermometer is required.

  Therefore, in the following Patent Document 1, the material of the protective tube is made of ceramics having excellent wear resistance, and the life of the thermometer is extended.

JP 2000-46657 A

  However, the thermometer described in Patent Document 1 has a problem that ceramics are expensive.

  The present invention has been made to solve such a problem, including a fluidized bed furnace capable of extending the life of a thermometer even if the protective tube is made of a low-cost material similar to the conventional one. An object is to provide a fluidized bed combustion furnace.

  The fluidized bed combustion furnace according to the present invention includes a combustion chamber that combusts the raw material while forming a fluidized bed in which the raw material and the fluidized material flow, and a thermometer for measuring the temperature of the combustion chamber passes through the furnace wall and measures the temperature. In a fluidized bed combustion furnace in which a part is covered with a protective tube and protrudes into the furnace, a refractory protrusion protruding into the furnace is provided above the protective tube on the inner surface of the furnace wall.

  According to such a fluidized bed combustion furnace, contact of the fluidized material falling along the furnace wall with the protective pipe is provided on the inner surface of the furnace wall above the protective pipe and projecting into the furnace. It can be avoided and wear of the protective tube can be reduced. As a result, the life of the thermometer can be extended even if the protective tube is made of an inexpensive material such as stainless steel as in the conventional case.

  Here, if the refractory projection is provided so as to cover the protective tube, the contact of the fluidized material with the protective tube can be further avoided, and the wear of the protective tube can be further reduced, resulting in a long life of the thermometer. Can be further improved.

  Further, when the upper surface of the refractory projection has an inclined surface that is inclined so as to guide the falling fluid material to the center side in the furnace, the falling fluid material follows this inclined surface. Actively approached to the center of the furnace. For this reason, the fluidized material can be easily returned to the fluidized bed, and at the same time, contact of the fluidized material with the protective tube can be further avoided. As a result, the wear of the protective tube can be further reduced, and the lifetime of the thermometer can be further increased.

  Here, specifically as a raw material which shows the said effect | action suitably, coal, biomass, or a waste tire is mentioned.

  According to the present invention as described above, it is possible to provide a fluidized bed combustion furnace capable of extending the life of the thermometer even when the protective tube is made of the same inexpensive material as the conventional one.

It is a schematic sectional lineblock diagram showing an important section of a fluidized bed combustion furnace concerning a 1st embodiment of the present invention. It is the figure which looked at the principal part of the fluidized-bed combustion furnace shown in FIG. 1 from the furnace inner side. It is an enlarged view which shows the thermometer and refractory protrusion part in FIG. 1 with a furnace wall. It is a schematic sectional block diagram which shows the principal part of the fluidized-bed combustion furnace which concerns on 2nd Embodiment of this invention.

  Hereinafter, preferred embodiments of a fluidized bed combustion furnace according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or an equivalent element, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a schematic cross-sectional configuration diagram showing the main part of a fluidized bed combustion furnace according to the first embodiment of the present invention, FIG. 2 is a view of the main part of the fluidized bed combustion furnace as seen from the inside of the furnace, and FIG. It is an enlarged view which shows a thermometer and a refractory protrusion part with a furnace wall, and this fluidized-bed combustion furnace is a fluidized-bed boiler here, and is used for a power station.

  As shown in FIG. 1, the fluidized bed boiler 100 generally has a rectangular cylindrical furnace whose upper and lower ends are closed, and its lower part narrows in the width direction (left and right direction in FIG. 1) as it goes downward, so that a rectangular cylinder is formed. The shape is reduced. In the fluidized bed boiler 100, the furnace wall 1 is a combustion chamber 2, and a fluidized material such as silica sand is previously stored in the combustion chamber 2 for the purpose of promoting complete combustion, and a plurality of fluidized bed boilers 100 are provided at the bottom of the combustion chamber 2. Combustion air is introduced into the combustion chamber 2 through the opening 3 and fuel such as coal and biomass is introduced into the lower portion of the combustion chamber 2 from the outside, and a fluidized bed is formed while these are flowing to burn the fuel. is there.

  As shown in FIG. 2, the furnace wall 1 of the fluidized bed boiler 100 connects water wall tubes (water pipes) 4, 4 arranged in parallel in the furnace wall circumferential direction (left and right direction in the figure) with flat fins 5. The so-called membrane panel 15 is provided. The water wall tube 4 exchanges heat generated in the combustion chamber 2 with water flowing in the water wall tube 4 and converts it into water vapor.

  As shown in FIGS. 1 and 2, the furnace wall 1 has an upper furnace wall A from which the membrane panel 15 is exposed, and a refractory 6 set under the upper furnace wall A. And the lower furnace wall B on which the membrane panel 15 is covered. Here, the refractory 6 is a refractory lining formed of an irregular refractory.

  In this fluidized bed boiler 100, as shown in FIGS. 1 to 3, a thermometer 7 for measuring the temperature of the combustion chamber 2 is installed. The thermometer 7 passes through the fins 5 and the refractory 6 constituting the lower furnace wall B, and is arranged so that the measurement part is covered with a protective tube 9 made of a material such as stainless steel and protrudes into the furnace. .

  Here, particularly in the present embodiment, a refractory projection 10 that protrudes into the furnace is provided on the inner surface of the furnace wall B above the protective tube 9 of the thermometer 7. The refractory projection 10 has a shape in which a part of the refractory 6 constituting the furnace wall B is expanded (projected) in an umbrella shape.

  Specifically, the refractory protrusion 10 has a triangular shape in a side view, and its upper surface guides the fluidized material falling along the furnace walls A and B to the center side in the furnace. It is set as the structure which has the inclined surface 11 which inclines with a downward slope toward the furnace inner side. And the refractory projection part 10 is provided so that the front-end | tip of the protective tube 9 may be hidden in planar view, and the said protective tube 9 may be covered.

  According to the fluidized bed boiler 100 having such a configuration, the combustion of fuel is performed in the combustion chamber 2, and the generated heat is transmitted to the water wall tube 4 to perform heat exchange. The combustion gas generated by the combustion is discharged from the upper part of the furnace to the subsequent stage, and the fluidized material containing ash descends along the furnace walls A and B in the furnace, and this is repeated.

  Here, according to the present embodiment, since the refractory protrusion 10 protruding into the furnace is provided on the inner surface of the furnace wall B above the protective tube 9, the refractory protrusion 10 causes the furnace wall. The contact of the fluid material falling along B with the protective tube 9 can be avoided, and wear of the protective tube 9 can be reduced. As a result, it is possible to extend the life of the thermometer 7 even if the protective tube 9 is made of a low-cost material such as stainless steel, for example.

  In addition, since the refractory projection 10 is provided so as to cover the protective tube 9, contact of the fluidized material with the protective tube 9 can be further avoided, and wear of the protective tube 9 can be further reduced. 7 can be further extended in life.

  Moreover, since the upper surface of the refractory projection 10 has an inclined surface 11 that inclines so as to guide the falling fluid to the center side in the furnace, it falls according to the inclined surface 11. The fluidized material is actively brought to the center side in the furnace. For this reason, the fluidized material can be easily returned to the fluidized bed, and at the same time, contact of the fluidized material with the protective tube 9 can be further avoided. As a result, the wear of the protective tube 9 can be further reduced, and the lifetime of the thermometer 7 can be further increased.

  And since the wear of the protective tube 9 can be reduced in this way, the frequency of erroneous indication of temperature during continuous operation is reduced, and as a result, the combustion state of the fluidized bed boiler 100 can be accurately grasped, and continuous operation of the entire power plant Reliability can be improved.

  FIG. 4 is a schematic cross-sectional configuration diagram showing a main part of a fluidized bed combustion furnace according to a second embodiment of the present invention. The second embodiment is different from the first embodiment in that the thermometer 7 is installed so as to penetrate the fin 5 of the membrane panel 15 which is the upper furnace wall A and is not covered with the refractory 6. Accordingly, the refractory projection 10 is provided above the protective tube 9 of the thermometer 7 on the inner surface of the upper furnace wall A (membrane panel 15).

  Also in the second embodiment, since the refractory projection 10 can avoid the fluid material falling along the furnace wall A from contacting the protective tube 9, the same effect as the first embodiment can be obtained. Can be obtained.

  As described above, the present invention has been specifically described based on the embodiment. However, the present invention is not limited to the above embodiment. For example, in the above embodiment, the shape of the refractory protrusion 10 is particularly preferable. As a side view triangle, a shape such as a side view trapezoid may be used.

  In the above embodiment, the combustion target is a fuel that generates heat, but it may be, for example, waste for incineration such as waste tires and garbage, and the main point is combustion including fuel and waste. Any material can be used.

  Moreover, in the above embodiment, the application to a fluidized bed boiler is described, but it can also be applied to a circulating fluidized bed boiler that is provided with a cyclone and returns ash such as combustion ash and unburned ash to the fluidized bed, Furthermore, the present invention can also be applied to a fluidized bed furnace that does not have a water pipe for heat exchange in the furnace. In short, it has a combustion chamber that burns the raw material while forming a fluidized bed in which the raw material and the fluidized material flow. Applicable to all fluidized bed combustion furnaces.

  2 ... Combustion chamber, 4 ... Water wall tube, 5 ... Fin, 6 ... Refractory, 7 ... Thermometer, 9 ... Protective tube, 10 ... Refractory projection, 11 ... Inclined surface of refractory projection, 15 ... Membrane Panel: 100 ... Fluidized bed boiler (fluidized bed combustion furnace), A ... Upper furnace wall (membrane panel), B ... Lower furnace wall (membrane panel and refractory).

Claims (4)

A combustion chamber is provided for combusting the raw material while forming a fluidized bed in which the raw material and the fluidized material flow. In a fluidized bed combustion furnace protruding into the furnace,
Above the protective tube on the inner surface of the furnace wall, it has a refractory projections projecting into the furnace,
An upper surface of the refractory projection has an inclined surface inclined downward from the furnace wall into the furnace.   The fluidized bed combustion furnace according to claim 1, wherein the refractory protrusion is provided so as to cover the protective tube. The inclined surface, fluidized bed combustion furnace according to claim 1, wherein the benzalkonium be tilting the flow material falling down so as to guide the center side of the furnace.   The fluidized bed combustion furnace according to any one of claims 1 to 3, wherein the raw material is coal, biomass, or waste tires.

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