JP5462214B2 - Fluidized bed furnace - Google Patents

Description

  The present invention relates to a fluidized bed furnace for extracting combustible gas from waste by heating the waste in a fluidized bed in which fluidized particles are fluidized.

  Conventionally, the thing of patent document 1 is known as a fluidized bed furnace. As shown in FIG. 5, the fluidized bed furnace has a furnace body 104 having fluidized sand (fluidized particles) 102 at the bottom of the furnace and fluidization of the fluidized sand 102 to form a fluidized bed. And an air supply unit 106 for supplying air into the sand 102. The furnace main body 104 has a side wall, and an input unit 108 for supplying waste on the fluidized bed is provided on the side wall.

  In the fluidized bed furnace 100, the air supply unit 106 supplies air into the high temperature fluidized sand 102 to fluidize the fluidized sand 102 in a suspended state, thereby forming a fluidized bed. The air supply unit 106 is configured so that the fluidized state of the fluidized sand 102 is substantially constant throughout the fluidized bed so that the waste introduced into the fluidized bed from the input unit 108 can be taken into the bed and burned efficiently. Supply air.

  Each time waste is thrown into the high-temperature fluidized sand from the charging unit 108, the waste is mixed with the high-temperature fluidized sand 102 in the fluidized bed and thermally decomposed (gasified). Thereby, combustible gas is generated. This combustible gas is burned at a high temperature in a subsequent melting furnace, for example.

JP 2006-242454 A

  The waste thrown into the fluidized bed furnace 100 is taken into an active fluidized bed and burned or gasified, but the combustible in the waste burns rapidly each time the waste is thrown intermittently. As a result, rapid fluctuations in the amount and concentration of the generated combustible gas are repeated. Since the variation in the gasification reaction greatly depends on the quantitativeness of the waste supply, if there is a variation in the waste supply or the waste quality, the combustible gas cannot be generated stably. In particular, when the waste contains a large amount of flammable garbage such as paper or sheet-like plastic, the generated flammable gas fluctuates more and its stabilization is required.

  For example, when power generation is performed using the generated combustible gas in a gas engine, stable energy cannot be obtained if the fluctuation of the combustible gas is large. Is required more.

  Therefore, an object of the present invention is to provide a fluidized bed furnace capable of stably obtaining a combustible gas even if the waste contains easily burnable garbage.

  Accordingly, in order to solve the above-mentioned problems, the present invention is a fluidized bed furnace for heating a waste and taking out a combustible gas from the waste, and a fluidized particle constituting a fluidized bed for heating the waste A bottom wall that supports the bottom wall and a side wall that rises from the bottom wall, and discharges the incombustible material in the waste together with the fluidized particles to a position biased in a specific direction from the center position of the bottom wall. A furnace body that is provided with a discharge port and is inclined so that the upper surface of the bottom wall is lowered toward the discharge port so that the incombustible material descends on the upper surface of the bottom wall toward the discharge port; A gas supply unit that fluidizes the fluidized particles by blowing fluidized gas from the bottom wall of the furnace body to the fluidized particles, a plurality of temperature detection units that detect the temperature of the fluidized bed, and the gas supply unit A control unit for controlling A waste supply unit that supplies the waste to a region adjacent to the supply-side side wall on the fluidized bed from a supply-side side wall that is opposite to the discharge port across the center position of the bottom wall of the recording side wall And comprising. The gas supply unit extends below the bottom wall in a direction orthogonal to the direction from the supply side wall toward the discharge port, and the fluid particles are moved from a predetermined position in the orthogonal direction. A plurality of wind boxes for injecting fluidized gas, and a supply unit for supplying the fluidized gas to each of these windboxes and adjusting the air ratio of the fluidized gas supplied to each of the windboxes And the plurality of wind boxes are arranged in a direction from the supply-side side wall toward the discharge port, and the plurality of temperature detection units are first closest to the supply-side side wall in the fluidized bed. In the first region that overlaps with the wind box in the vertical direction, the temperature of the upper position and the lower position that are vertically spaced apart is detected, and the second wind box that is closest to the discharge port in the fluidized bed or the discharge position. Overlap with exit In each of the two regions, the control unit is disposed at a position where the temperature between the upper side position and the lower side position which are vertically spaced can be detected, and the control unit is configured to detect the first region based on the temperature detected by each temperature detection unit. The air ratio of the fluidized gas supplied to each wind box by the supply unit is adjusted so that the temperature of the fluidized bed increases toward the second region.

  According to the present invention, combustibility is generated by supplying waste by the waste supply unit to the first region side of the fluidized bed whose temperature is increasing from the first region toward the second region. Rapid fluctuations in the amount and concentration of gas are suppressed, and as a result, combustible gas can be stably generated from waste.

  Specifically, by supplying the waste to the first region where the temperature is low in the fluidized bed, the rapid combustion of flammable garbage in the waste is suppressed, and the combustibility due to the gasification of the waste is suppressed. There is little generation of gas. This waste is disposed inside the furnace body toward the discharge port (i.e., the first of the fluidized bed) due to the flow of fluidized particles constituting the fluidized bed and the supply of new waste into the furnace body by the waste supply unit. Move towards 2 areas). Then, since the temperature in the second region is high, the waste that has moved from the first region side is sufficiently gasified to generate combustible gas. Thereby, intermittent and rapid generation | occurrence | production of combustible gas is suppressed, and generation | occurrence | production of the said gas can be stabilized.

  In addition, in order to adjust the temperature of each region of the fluidized bed by adjusting the air ratio of the fluidized gas supplied to each region of the fluidized bed in the direction from the supply side wall to the discharge port, the fluidized bed has a poor fluidity. Is less likely to occur. That is, the air ratio of the fluidized gas supplied to the fluidized bed (i.e., maintaining the fluidized state of the fluidized particles in each region by sufficiently maintaining the flow rate of the fluidized gas supplied to each region of the fluidized bed (i.e. The temperature of each region is adjusted by adjusting the oxygen concentration.

  In addition, by detecting the temperatures of the upper and lower positions spaced apart in the vertical direction in the first region and the second region, respectively, this can be reliably detected when a flow failure occurs in the region. Can do. Specifically, when the fluidized gas is supplied from the bottom wall into the fluidized bed, the fluidized gas flows upward if the fluidized particles in the region to which the fluidized gas is supplied are sufficiently fluidized. Although it is easy to proceed in the bed, if the flow failure occurs in the region, the fluidized gas is difficult to travel in the fluid bed upward. Therefore, the flowing particles are not sufficiently agitated in the region where the flow failure occurs, thereby causing a temperature difference between the upper side and the lower side, and the flow failure can be detected by detecting this temperature difference.

  In addition, since the upper surface of the bottom wall of the furnace body is inclined so as to become lower toward the discharge port, the non-combustible material in the waste that has sinked to the bottom wall in the fluidized bed is the upper surface of the bottom wall toward the discharge port. Descent up. Thereby, the said incombustible material can be easily discharged | emitted from a furnace main body.

  Between the first region and the second region in the fluidized bed, the plurality of temperature detection units are respectively disposed at positions where temperatures can be detected at predetermined intervals in a direction from the supply side wall toward the discharge port. It is preferable.

  According to such a configuration, since the temperature between the first region and the second region can be detected, a temperature abnormality such as a local decrease in temperature occurs between the first region and the second region. This can be detected in the case of the occurrence of a local temperature abnormality.

  In this case, each temperature detection part arrange | positioned between the said 1st area | region and a 2nd area | region is each wind box arrange | positioned between the said 1st wind box and the said 2nd wind box, and an up-down direction It is more preferable that they are arranged at positions where the temperature of each region overlapping with each other can be detected.

  According to such a configuration, since the temperature of the region through which the fluidized gas supplied from each wind box passes in the fluidized bed can be detected, the adjustment of the air ratio of the fluidized gas supplied to each wind box can be performed. It becomes easy.

  In each region that overlaps with the wind box between the first region and the second region in the vertical direction, each temperature detection unit can detect the temperature between the upper position and the lower position that are spaced vertically. It is preferable that they are arranged respectively.

  According to such a configuration, it is possible to suitably detect a flow failure in each region from the first region to the second region in the fluidized bed.

  As described above, according to the present invention, it is possible to provide a fluidized bed furnace capable of stably obtaining a combustible gas even if it is a waste containing easily burnable garbage.

It is a schematic structure figure of a fluidized bed furnace concerning this embodiment. It is the II-II transverse cross section of FIG. It is a figure for demonstrating arrangement | positioning of the upper area | region and temperature sensor in the fluidized bed of the said fluidized bed furnace. It is a figure for demonstrating arrangement | positioning of the temperature sensor in the fluidized-bed furnace which concerns on other embodiment. It is a schematic block diagram of the conventional fluidized bed furnace.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  The fluidized bed furnace (fluidized bed furnace) according to the present embodiment is a furnace for extracting combustible gas from waste by heating the waste with high-temperature fluidized particles (fluidized sand). As shown in FIGS. 1 and 2, the fluidized bed furnace includes a furnace body 20 having fluidized particles 12 constituting a fluidized bed 14 therein, a gas supply unit 30 that supplies fluidized gas into the furnace body, and A plurality of temperature sensors (temperature detection units) 40 for detecting the temperature of the fluidized bed 14, a control unit 50 for controlling the gas supply unit 30, and a waste supply unit 60 for supplying the waste 18 into the furnace body 20. .

  The fluidized particles 12 constitute the fluidized bed 14 inside the furnace body 20 and are particles for heating the waste 18. That is, when the fluidized particles 12 heated to a high temperature by the combustion of a part of the waste 18 are mixed with the waste 18, the waste 18 is gasified to generate a combustible gas. In the present embodiment, silica sand or the like is used as the fluid particles 12.

  The furnace body 20 takes out the combustible gas from the waste 18 by the high-temperature fluidized particles 12. The furnace body 20 includes a bottom wall 21 that supports the fluidized particles 12 from below, a side wall 22 that rises from the bottom wall 21, and a combustible gas discharge part 23 that is provided at the upper end of the side wall 22.

  The side wall 22 has a rectangular tube shape extending vertically. Specifically, the side wall 22 includes a front wall (supply side wall) 24 and a rear wall 25 that are opposed to each other at an interval in the front-rear direction (left and right in FIG. 2), and ends of the front wall 24 and the rear wall 25. There are lateral walls 26, 26 connected to each other. The lateral walls 26, 26 are parallel to each other. That is, the furnace body 20 has a planar shape in which the dimension in the width direction, which is the distance between the lateral walls 26, 26, is uniform in the front-rear direction.

  A waste insertion port 28 for inserting the waste 18 into the furnace body 20 is inserted into a side wall (front wall) 24 located on the opposite side of the discharge port 29 across the center position of the bottom wall 21. Is provided. In this embodiment, as shown in FIG. 2, the front-rear direction refers to the front-rear direction in the furnace body 20 (the left-right direction in FIG. 2), and the width direction refers to the width direction in the furnace body 20 (in FIG. 2). (Vertical direction).

  The waste insertion port 28 is provided at the center in the width direction at the lower part of the front wall 24. The waste insertion port 28 is at a height position where the waste 18 can be pushed sideways onto the upper surface of the fluidized particles 12 (fluidized bed 14) supported by the bottom wall 21 of the furnace body 20, that is, the fluidized bed 14. The lower end of the waste insertion port 28 is provided at a position slightly higher than the upper surface.

  The combustible gas discharge part 23 is a part for discharging the combustible gas generated in the furnace body 20. The combustible gas discharge part 23 has an outer diameter smaller than that of the side wall 22 so that a duct or the like for supplying the combustible gas obtained in the furnace body 20 to a gas engine or the like of a subsequent power generation process can be connected. ing.

  The bottom wall 21 is provided with a discharge port 29 for discharging the incombustible material in the waste 18 together with the flowing particles 12 at a position deviated from the center position in a specific direction. The discharge port 29 opens in the center portion in the width direction of the offset position on the bottom wall 21. The upper surface 21a of the bottom wall 21 is inclined so as to become lower toward the discharge port 29 so that incombustibles or the like descend on the upper surface 21a. The upper surface 21a of the bottom wall 21 of the present embodiment includes a region 211 on the front side (left side in FIG. 2) of the discharge port 29, a region 212 on the rear side (right side in FIG. 2), and the width of the discharge port 29. It is divided into regions 213 and 214 on both sides in the direction. And each area | region 211,212,213,214 is an inclined surface used as the fixed downward slope toward the discharge port 29. FIG. That is, the discharge port 29 is provided at the lowest position on the upper surface 21 a of the bottom wall 21.

  The gas supply unit 30 fluidizes the fluidized particles 12 by blowing fluidized gas into the fluidized particles 12 from the bottom wall 21. The gas supply unit 30 supplies a plurality of nozzles 31 disposed on the bottom wall 21, a plurality of wind boxes 32 that distribute the fluidized gas to the nozzles 31, and a fluidized gas to each of the wind boxes 32. And a supply unit 33. In the present embodiment, a plurality of nozzles 31 are arranged on the bottom wall 21 in the width direction, and a row of nozzles 31 arranged in the width direction is arranged in the front-rear direction. In other words, the plurality of nozzles 31 are arranged on the bottom wall 21 in a lattice shape spaced in the width direction and the front-rear direction. Each nozzle 31 is attached to the bottom wall 21 so as to penetrate the bottom wall 21. The arrangement position of each nozzle 31 is not limited to the lattice arrangement.

  Each wind box 32 blows fluidizing gas into the furnace body 20 through a nozzle 31 from a predetermined position in the width direction of the bottom wall 21. The wind box 32 is disposed below the bottom wall 21 and has a box shape extending in the width direction. The wind box 32 serves as a header for distributing the fluidized gas to the nozzles 31 arranged in the width direction on the bottom wall 21, and the flow rate of the fluidized gas blown from the nozzles 31 arranged in the width direction is made uniform. It has a function to do. In the present embodiment, a common fluidized gas is distributed from one wind box 32 to the nozzles 31 arranged in two front and rear rows.

  The plurality of wind boxes 32 are arranged in the front-rear direction on the lower surface side of the bottom wall 21. Thereby, for each nozzle 31 corresponding to each wind box 32, the component and flow rate of the fluidizing gas blown from the nozzle 31 can be changed. In the present embodiment, three wind boxes 32a, 32b, 32c are arranged in the front-rear direction below the bottom wall 21. Specifically, two wind boxes (a first wind box 32 a and a second wind box 32 b) are arranged on the lower side of the bottom wall 21 and closer to the front wall 24 than the discharge port 29. One wind box (third wind box 32c) is arranged on the 25th side.

  The supply unit 33 includes an air supply unit 34 for supplying air (oxygen), a water vapor supply unit 35 for supplying water vapor, and a pipe line 36 that connects the supply units 34 and 35 to the wind boxes 32. The air and the water vapor are respectively supplied to the wind box 32 from the supply parts 34 and 35 through the pipes 36. In the present embodiment, fluidized gas is constituted by the air or / and water vapor supplied from the air supply unit 34 and the water vapor supply unit 35 to the wind box 32.

  Each pipe line 36 is provided with valves 37a, 37b, 37c, 38a, 38b, and 38c for adjusting the flow rate of the fluid (air or water vapor in this embodiment) flowing through the pipe line 36, respectively. Each valve 37 a, 37 b, 37 c, 38 a, 38 b, 38 c changes the opening degree according to a control signal from the control unit 50. As a result, the air ratio (oxygen concentration) and flow rate of the fluidized gas supplied from each wind box 32 into the furnace body 20 are adjusted.

  The plurality of temperature sensors 40 are sensors that detect the temperature of the fluidized bed 14 and are arranged in the furnace body 20. Each temperature sensor 40 is connected to the control unit 50, converts the detected temperature into a temperature signal, and outputs the temperature signal to the control unit 50.

Each temperature sensor 40 has an upper position in the fluidized bed 14 that overlaps with the wind box 32 in the vertical direction (hereinafter, also simply referred to as “upper region”) ua ₁ , ua ₂ , ua ₃ and is spaced upward and downward. It arrange | positions so that the temperature with a lower side position can be detected, respectively. In the present embodiment, six temperature sensors 40 are arranged. Specifically, the upper region (first region) ua ₁ of the first wind box 32a, the upper region (third region) ua _{3 of} the second wind box 32b, and the upper region (second region) of the third wind box 32c. ) _Two temperature sensors 40 are arranged in each of ua ₂ . In the present embodiment, since the three wind boxes 32 are provided in the furnace body 20, the number of the upper regions ua ₁ , ua ₂ and ua ₃ is three. However, if the number of the wind boxes 32 increases, Correspondingly, the number of upper regions ua ₁ , ua ₂ , ua ₃ ,. The upper position is a position above the center of the fluidized bed 14 in the vertical direction, and the lower position is a position below the center. However, the upper position is a position not less than a predetermined depth that is not easily affected by the temperature above the upper surface of the fluidized bed 14 or the temperature of the waste, and the lower position is not easily influenced by the temperature of the bottom wall 21 itself. It is a position above the upper surface 21a of the bottom wall 21 by a predetermined distance or more.

The two temperature sensors 40 arranged in each upper region ua ₁ , ua ₂ , ua ₃ only need to be able to detect the temperatures of the upper and lower positions in the upper region ua ₁ , ua ₂ , ua ₃ . It does not have to be arranged at a position overlapping in the direction. That is, the temperature sensor 40 for detecting the temperature of the upper position and the temperature sensor 40 for detecting the temperature of the lower position are respectively arranged at positions shifted in the width direction in the upper regions ua ₁ , ua ₂ , ua ₃ (FIG. 2). The temperature sensor 40 that detects the temperature of the upper position and the temperature sensor 40 that detects the temperature of the lower position are upper regions ua ₁ , ua ₂ , ua ₃ (more specifically, nozzles in the front row) The nozzles 31 may be disposed at positions shifted in the front-rear direction within a region between the nozzles 31 and the nozzles 31 of the nozzles 31 in the rear row (see the hatched portion in FIG. 3).

Further, if the temperature sensor 40 is arranged so as to be able to detect the temperature of the upper side position and the lower side position in the first area ua ₁ and the second area ua ₂ , the other upper area (in this embodiment, The number may be one in the third region ua ₃ ). Further, three or more temperature sensors 40 may be disposed in each of the upper regions ua ₁ , ua ₂ , and ua ₃ .

If the temperature sensors 40 are arranged so that the temperatures of the upper position and the lower position can be detected at least in the first area ua ₁ and the second area ua ₂ , they are arranged in the furnace body 20. The specific number and arrangement position of the temperature sensors 40 are not limited.

For example, one temperature sensor 40 may be disposed between the first region ua ₁ and the second region ua ₂ in the fluidized bed 14, and the plurality of temperature sensors 40 have a temperature at a predetermined interval in the front-rear direction. (For example, arranged in a line before and after when viewed from the width direction (see FIG. 4)). In this case, each temperature sensor 40 may be disposed in each upper region (the third region ua _{3 in} the present embodiment) located between the first region ua ₁ and the second region ua _2, and The upper regions ua ₁ , ua ₂ , and ua ₃ may be arranged at predetermined intervals in the front-rear direction. By arranging in this way, the temperature between the first region ua ₁ and the second region ua ₂ in the fluidized bed 14 can be detected, and therefore, between the first region ua ₁ and the second region ua _2. It is possible to detect a local temperature abnormality of the fluidized bed 14 such as a local temperature drop.

Further, in each upper region ua ₃ ,... Between the first region ua ₁ and the second region ua ₂ , the temperature sensor 40 may be disposed at a position where the temperature between the upper position and the lower position can be detected. preferable. By arranging each temperature sensor 40 in this way, it is possible to suitably detect a flow failure in each upper region ua ₃ ,... From the first region ua ₁ to the second region ua ₂ in the fluidized bed 14. Specifically, when the fluidizing gas is supplied from the bottom wall 21 into the fluidized bed 14, if the fluidized particles 12 in the region to which the fluidizing gas is supplied are sufficiently fluidized, the fluidizing gas is directed upward. Although it is easy to advance in the fluidized bed 14, the fluidized gas is difficult to travel upward in the fluidized bed 14 if a flow failure occurs in the region ua. Therefore, the fluidized particles 12 are not sufficiently stirred in the region where the flow failure occurs and in the vicinity thereof, thereby causing a temperature difference between the upper position and the lower position in the region, and by detecting this temperature difference, the temperature difference is detected. It is possible to detect poor flow in the region.

  Based on the temperature detected by each temperature sensor 40, the controller 50 causes the supply unit 33 to increase the temperature of the fluidized bed 14 toward the rear side (that is, from the front wall 24 toward the rear wall 25). The air ratio of the fluidized gas supplied to each wind box 32 is adjusted. Thereby, rapid fluctuations in the amount and concentration of the combustible gas generated in the fluidized bed furnace 10 are suppressed, and as a result, the combustible gas can be stably generated from the waste 18.

  Further, the control unit 50 detects a flow abnormality (such as a local flow failure) generated in the fluidized bed 14 based on the temperature detected by each temperature sensor 40 and controls the gas supply unit 30 to control the furnace body 20. By adjusting the air ratio and flow rate of the fluidizing gas supplied to the inside, this flow abnormality is eliminated.

Specifically, the control part 50 controls the temperature of each area | region in the front-back direction of the fluidized bed 14 with the following method (1st method). In the present embodiment, the upper temperature sensor 40 in FIG. 1 is the first temperature sensor, the second temperature sensor, and the third temperature sensor in order from the left, and the lower temperature sensor is the fourth temperature sensor and the fifth temperature in order from the left. When the sensor is the sixth temperature sensor, the temperature detected by the first temperature sensor is T ₁ , the temperature detected by the second temperature sensor is T ₂ , the temperature detected by the third temperature sensor is T ₃ , The temperature detected by the fourth temperature sensor is T ₄ , the temperature detected by the fifth temperature sensor is T ₅ , and the temperature detected by the sixth temperature sensor is T ₆ .

When the control unit 50 receives the temperature signal from each temperature sensor 40 and acquires the temperature of each region of the fluidized bed 14 (the region where each temperature sensor 40 is disposed), the average value Ave1 of T ₁ and T ₄ , obtaining an average value Ave2 of T ₂ and _{T 5, T 3} and the average value Ave3 of _{T 6,} respectively. Then, the control unit 50 compares these average values Ave1, Ave2, and Ave3.

  When the relationship of “Ave1 <Ave2 <Ave3” is broken, the control unit 50 temporarily increases the flow rate of the fluidized gas supplied to each wind box 32 by the supply unit 33. Here, the control unit 50 of the present embodiment constantly monitors the relationship of “Ave1 <Ave2 <Ave3”, but may monitor the relationship of “Ave1 <Ave2 <Ave3” at predetermined time intervals.

Specifically, when “Ave1> Ave2” or “Ave2> Ave3” is detected and the temperature abnormality is detected, the control unit 50 increases the flow rate of the fluidized gas supplied to each wind box 32. At this time, the control unit 50 fluidizes the air supplied to each wind box 32 by being blown from the wind box 32 into the furnace body 20 while keeping the ratio of the air and water vapor (that is, the air ratio of the fluidized gas) constant. Only the gas flow rate is increased. Specifically, when the control unit 50 detects the temperature abnormality, the flow rate of the fluidizing gas blown into the fluidized bed 14 from each wind box 32 is changed from a normal flow rate (for example, U _o / U _mf = 3.0). Increase temporarily (for example, the flow rate after the increase is U _o / U _mf = 5.0). Here, U _mf is the minimum fluidizing velocity is the minimum flow rate of the blowing of the fluidizing gas for fluidizing the fluidized particles 12, U _o is the average cross-sectional velocity of the fluidizing gas.

Then, when the temperature detected by each temperature sensor 40 satisfies the relationship of “Ave1 <Ave2 <Ave3”, the control unit 50 controls the supply unit 33 to blow into the fluidized bed 14 from each wind box 32. The gas flow rate is restored (in the above example, U _o / U _mf = 5.0 to 3.0), and temperature monitoring continues. On the other hand, if the temperature detected by each temperature sensor 40 does not satisfy the relationship of “Ave1 <Ave2 <Ave3” even if the flow rate of the fluidizing gas is increased and a predetermined time elapses, the controller 50 It is determined that an abnormality has occurred, and the operation of the fluidized bed furnace 10 is stopped.

  More specifically, for example, in a normal operation state of the fluidized bed furnace 10 in which no temperature abnormality occurs in the fluidized bed 14, Ave1 is around 600 ° C, Ave2 is around 650 ° C, and Ave3 is around 700 ° C. It is assumed that Ave1 has reached 660 ° C. due to fluctuations in the amount or / and components of the waste 18 supplied into the furnace body 20 from this state. At this time, the control unit 50 detects a temperature abnormality (Ave1> Ave2), and temporarily increases the flow rate of the fluidized gas blown into the fluidized bed 14 from each wind box 32. Then, Ave 1 becomes 700 ° C., Ave 2 becomes 750 ° C., Ave 3 becomes 800 ° C., and the temperature of the fluidized bed 14 rises as a whole. The balance is restored, and the temperatures detected by the temperature sensors 40 satisfy the relationship of “Ave1 <Ave2 <Ave3”. Thereafter, when the flow rate of the fluidizing gas blown into the fluidized bed 14 from each wind box 32 by the control unit 50 is restored, Ave1 returns to around 600 ° C., Ave2 returns to around 650 ° C., and Ave3 returns to around 700 ° C. The temperature abnormality that occurred in the layer is eliminated.

Note that, even if the temperature detected by each temperature sensor 40 satisfies the relationship of “Ave1 <Ave2 <Ave3”, the control unit 50 has a predetermined range (min ₁ <Ave1 <max ₁ , _and, when the _{off-min 3 <Ave3 <max 3)} , may be temporarily increasing the flow rate of the fluidizing gas for blown into the fluidized bed 14 from Kakukazebako 32. Thereby, the control unit 50 can more suitably maintain the temperature distribution in the front-rear direction of the fluidized bed (that is, the temperature distribution in which the temperature gradually increases from the front wall 24 toward the rear wall 25).

  Moreover, the control part 50 may control the temperature of each area | region in the front-back direction of the fluidized bed 14 with the following method (2nd method).

  The control unit 50 monitors the relationship of “Ave1 <Ave2 <Ave3” as in the above method. That is, the control unit 50 receives the temperature signal from each temperature sensor 40, acquires the temperature of each region of the fluidized bed 14, obtains Ave1, Ave2, and Ave3, and calculates the average values Ave1, Ave2, and Ave3. Compare. Also in this method, the control unit 50 may always monitor the relationship of “Ave1 <Ave2 <Ave3”, or may monitor the relationship of “Ave1 <Ave2 <Ave3” at predetermined time intervals. Good.

When the relationship of “Ave1 <Ave2 <Ave3” is broken, the control unit 50 adjusts the ratio of air and water vapor supplied to the wind box 32 corresponding to the abnormal region by the supply unit 33. For example, if Ave1> Ave2 and becomes abnormally high temperature in the first region ua ₁ of the fluidized layer 14 occurs, the control unit 50 controls the supply unit 33 is blown into the fluidized bed 14 from the first wind box 32 While keeping the flow rate of the fluidizing gas constant, the valve 37a is throttled and the valve 38a is opened to reduce the flow rate of air supplied to the first wind box 32 and increase the flow rate of water vapor. Thereby, the air ratio of the fluidized gas blown into the fluidized bed 14 from the first wind box 32 is reduced (that is, the oxygen concentration is reduced). Then, the control unit 50 continues to monitor the temperature, and when Ave1 <Ave2, the valves 37a and 38a are returned to their original positions (that is, the valve 37a is opened and the valve 38a is throttled) to flow from the first wind box 32. The air ratio (oxygen concentration) of the fluidizing gas blown into the layer 14 is restored. On the other hand, if the temperature is Ave1> Ave2 even after a predetermined time has elapsed since the air ratio of the fluidized gas blown into the fluidized bed 14 from the first wind box 32 is reduced, the control unit 50 is The operation of the fluidized bed furnace 10 is stopped when it is determined that an abnormality has occurred in 20.

Note that, even if the temperature detected by each temperature sensor 40 satisfies the relationship of “Ave1 <Ave2 <Ave3”, the control unit 50 has a predetermined range (min ₁ <Ave1 <max ₁ , And when it deviates from min ₃ <Ave3 <max ₃ ), in order to return Ave1 and Ave3 within a predetermined range, the opening degree of each valve 37a, 37c, 38a, 38c is adjusted, and the first wind box The air ratio of fluidized gas blown into the fluidized bed 14 from 32a or the air ratio of fluidized gas blown into the fluidized bed 14 from the third wind box 32c may be adjusted. Specifically, when a low temperature abnormality occurs in the first region ua ₁ of the fluidized bed 14, the control unit 50 controls the supply unit 33 to open the valve 37 a and throttle the valve 38 a, whereby the first wind box 32 a The air ratio of fluidized gas blown into the fluidized bed 14 is increased. Further, when a high temperature abnormality occurs in the second region ua ₂ of the fluidized bed 14, the control unit 50 controls the supply unit 33 to throttle the valve 37 c and open the valve 38 c, thereby flowing from the third wind box 32 c. The air ratio of the fluidizing gas blown into the layer 14 is reduced. Further, when a high temperature abnormality occurs in the second region ua ₂ of the fluidized bed 14, the control unit 50 controls the supply unit 33 to open the valve 37 c and throttle the valve 38 c, thereby flowing from the third wind box 32 c. The air ratio of the fluidizing gas blown into the layer 14 is increased.

  Further, the control unit 50 monitors a local temperature abnormality of the fluidized bed 14 that occurs when a fluid abnormality of the fluidized bed 14 (such as a local fluid failure in the fluidized bed 14) occurs, and this temperature abnormality is detected. Then, the flow abnormality of the fluidized bed 14 is eliminated by controlling the supply unit 33 and adjusting the air ratio and flow rate of the fluidized gas supplied to each wind box 32.

  Specifically, since the flowability of the fluidized gas is different from the other regions in the region where the flow failure occurs, the fluidized particles 12 are not sufficiently stirred, thereby causing a temperature difference between the upper side and the lower side. . Therefore, the control unit 50 detects the local flow failure in the fluidized bed 14 by detecting this temperature difference, that is, the flow abnormality of the fluidized bed 14, and the flow rate of the fluidized gas supplied into the furnace body 20. This can be solved by adjusting.

  Specifically, the control unit 50 controls the temperature in the vertical direction (vertical direction) in each region of the fluidized bed 14 by the following method.

When the control unit 50 receives the temperature signal from each temperature sensor 40 and acquires the temperature of each region of the fluidized bed 14 (the region in which each temperature sensor 40 is disposed), Temperature differences ΔT ₁ (= T ₁ −T ₄ ), ΔT ₂ (= T ₂ −T ₅ ), and ΔT ₃ (= T ₃ −T ₆ ) with respect to the lower position are obtained. Then, the control unit 50 compares each temperature difference ΔT ₁ , ΔT ₂ , ΔT ₃ with a predetermined value set in advance to determine whether or not a local fluid failure occurs in the fluidized bed 14. Perform monitoring (detection). Note that this monitoring may be performed all the time or may be performed at predetermined time intervals.

For example, when the predetermined value is ± 10 ° C., the control unit 50 determines that ΔT ₁ , ΔT ₂ , ΔT ₃ > 10 ° C., or ΔT ₁ , ΔT ₂ , ΔT ₃ <−10 ° C. The flow rate of the fluidized gas supplied to the corresponding area is temporarily increased. Specifically, when ΔT ₁ <−10 ° C., the control unit 50 controls the supply unit 33 so that the flow rate of the fluidized gas blown into the fluidized bed 14 from the first wind box 32a is the normal flow rate. (For example, U _o / U _mf = 3.0) is temporarily increased (for example, the increased flow rate is U _o / U _mf = 5.0). At this time, only the flow rate is increased so that the air ratio of the fluidizing gas does not change. When ΔT ₁ > −10 ° C. and ΔT ₁ <10 ° C., the control unit 50 controls the supply unit 33 to obtain the flow rate of the fluidized gas blown into the fluidized bed 14 from the first air box 32a. ( _E.g. , U _o / U _mf = 5.0 to 3.0) and continue to monitor temperature. On the other hand, the controller 50 determines that an abnormality has occurred in the furnace body 20 if ΔT ₁ <−10 ° C. even if a certain time has elapsed after increasing the flow rate, and the operation of the fluidized bed furnace 10 is performed. To stop.

  The control unit 50 also controls the waste supply unit 60 and the like.

  The waste supply unit 60 supplies the waste 18 from the front wall 24 to a region adjacent to the front wall 24 on the fluidized bed 14. As the waste supply part 60 of this embodiment, a screw pushing machine is used. Thereby, the waste 18 can be continuously supplied into the furnace while ensuring sealing performance. Moreover, litter that is small in bulk specific gravity such as paper or plastic sheet and easily scatters can be supplied into the furnace main body 20 as a lump. Therefore, it is possible to prevent these garbage from scattering. The specific configuration of the waste supply unit 60 is not limited. For example, in the waste supply unit 60 of the present embodiment, the screw pusher pushes the waste 18 into the furnace, but the waste 18 may be pushed into the furnace by a pusher or the like.

  In the fluidized bed furnace 10 configured as described above, the combustible gas is recovered from the waste 18 as follows.

  At the start of operation of the fluidized bed furnace, the control unit 50 blows fluidized gas from each wind box 32 to the fluidized particles 12 supported on the bottom wall 21 in the furnace body 20. At the start of operation, since there is no waste 18 (or a small amount if any) in the fluidized bed 14, the control unit 50 heats the fluidized particles 12 as the fluidized medium from above the fluidized bed 14 with a burner (not shown) or the like. To do. At this time, the control part 50 makes a fluid state by supplying only air from each wind box 32 to the fluid particles 12 without blowing water vapor, and heats the fluid particles 12 in this state. When the entire fluidized bed 14 reaches a predetermined temperature (for example, 600 ° C.), the control unit 50 starts to throw the waste 18 into the furnace body 20 by the waste supply unit 60. At this time, the control unit 50 gradually suppresses the operation of the burner or the like, and restricts the supply amount of air while increasing the addition amount of water vapor so as to be a predetermined ratio.

  The air ratio of the fluidizing gas blown into the fluidized particles 12 from each wind box 32 is obtained in advance as a value suitable for the operation of the fluidized bed furnace 10 and stored in the control unit 50. That is, in the fluidized bed furnace 10 in operation, if there is no temperature abnormality in the fluidized bed 14, the controller 50 does not adjust the opening degree of each valve 37a, 37b, 37c, 38a, 38b, 38c, Air and water vapor are supplied to each wind box 32 at a predetermined flow rate.

  Thus, the fluidized bed 12 is formed in the furnace body 20 by the fluidized particles 12 becoming fluidized. At this time, the flow rate of the fluidized gas blown into the fluidized bed 14 from each wind box 32 is the same, but the air ratio is different. Specifically, in the fluidized bed 14, the control unit 50 has a second ratio higher than the air ratio of the fluidized gas supplied to the first wind box 32 a so that the temperature increases from the front wall 24 toward the rear wall 25. The air ratio of the fluidizing gas supplied to the wind box 32b is large, and the air ratio of the fluidizing gas supplied to the third wind box 32c is larger than the air ratio of the fluidizing gas supplied to the second wind box 32b. Is adjusted so that the opening degree of each valve 37a, 37b, 37c, 38a, 38b, 38c is adjusted.

  As described above, the control unit 50 maintains the fluidized state of each region in the fluidized bed 14 by keeping the flow rate of the fluidized gas blown into the fluidized bed 14 from each wind box 32 constant. A predetermined temperature distribution (that is, a temperature distribution in which the temperature increases from the front wall 24 toward the rear wall 25) is formed by changing the oxygen concentration in each region within 14.

  When Ave 1 is around 600 ° C., Ave 2 is around 650 ° C., and Ave 3 is around 700 ° C., the control unit 50 determines that the inside of the furnace is in a steady state and starts temperature control of the fluidized bed 14. In the present embodiment, the controller 50 determines the temperature of the fluidized bed 14 so that the temperature difference between Ave 1 and Ave 3 is 50 ° C. or more, Ave 1 is 600 ° C. to 700 ° C., and Ave 3 is 700 ° C. to 800 ° C. Take control.

Specifically, the screw pusher (waste supply unit 60) pushes the waste 18 into the furnace body 20 sideways. As a result, the waste 18 is pushed onto the first region ua ₁ (see FIGS. 1 and 2). Since the active fluidized bed 14 is formed in the furnace body 20, the input waste 18 is diffused from the front wall 24 side toward the rear wall 25 side by the diffusion action while being taken into the fluidized bed 14. Moving. The waste 18 in the fluidized bed 14 does not move only in one direction from the front wall 24 to the rear wall 25, but is repeatedly discarded in a reciprocating manner in the vertical direction, the horizontal direction, and the front-rear direction. The density of the objects 18 gradually diffuses and moves from a high density area to a low density area (that is, from the input side (front wall 24) to the rear wall 25).

At this time, since the temperature of the first region ua ₁ of the fluidized bed 14 is low, rapid combustion of the waste 18 is suppressed, and the waste 18 that is easily gasified is gasified. That is, the waste 18 that is easily gasified, such as plastic and paper, is gasified in the first region ua ₁ and the adjacent region. On the other hand, some of wood chips and the like that are difficult to gasify are partially gasified, but most are not gasified and gradually move to the rear wall 25 side by the flow of fluidized particles, etc., and reach the second region ua ₂ To do. Thus, the easy waste 18 gasified gas under mild conditions (low temperatures) in the first region ua ₁ and around before reaching the second region ua ₂ (area of the second region ua ₂ side) By making it, the fluctuation | variation of the combustible gas to generate | occur | produce can be suppressed.

  Then, in the region on the front wall 24 side, the waste 18 that has moved in the fluidized bed 14 is sufficiently mixed with the fluidized particles 12 in the region overlapping the discharge port 29 in the vertical direction and the high-temperature region around it. The unburned waste 18 is sufficiently gasified.

  As described above, the waste 18 is continuously supplied by the screw pusher 60 in a state where the temperature of the fluidized bed 14 is increased from the front wall 24 toward the rear wall 25, thereby intermittently injecting the combustible gas. And rapid generation can be suppressed, and generation of the combustible gas can be stabilized.

  The fluidized particles 12 discharged together with incombustibles and the like from the outlet 29 in the fluidized bed 14 are separated from the incombustibles and the like as necessary, and are put into the furnace body 20 again.

  It should be noted that the temperature distribution of the fluidized bed 14 may be abnormal (locally low temperature region or high region may be generated) or flow abnormality due to the amount of waste 18 input or the components of dust contained in the waste 18. When the occurrence of (such as local flow failure in the fluidized bed 14) occurs, the control unit 50 controls the gas supply unit 30 based on the temperature detected by each temperature sensor 40 as described above. By adjusting the flow rate of air supplied to each wind box 32 and the flow rate of water vapor, the temperature distribution abnormality and the flow abnormality of the fluidized bed 14 are eliminated.

  The combustible gas generated in the furnace main body 20 is supplied from the combustible gas discharge section 23 of the furnace main body 20 to, for example, a gas engine of a power generation process, for example, through a duct connected to the combustible gas discharge section 23. Is done. At this time, the water vapor contained in the combustible gas is condensed and recovered as water by lowering the temperature of the combustible gas. As a result, the combustible gas from which the water vapor has been removed is supplied to the subsequent stage of the fluidized bed furnace 10.

As described above, in the fluidized bed furnace 10 described above, the waste supply unit 60 disposes the fluidized bed 14 on the first region ua ₁ side where the temperature increases from the first region ua ₁ toward the second region ua _2. By supplying the object 18, rapid fluctuations in the amount and concentration of the combustible gas to be generated are suppressed, and as a result, the combustible gas can be stably generated from the waste 18.

Specifically, by supplying the waste 18 to the first region ua ₁ side where the temperature is low in the fluidized bed 14, rapid combustion of flammable garbage in the waste 18 is suppressed, and the waste 18 There is little generation of combustible gas by gasification. The waste 18 is disposed inside the furnace body 20 by the flow of the fluidized particles 12 constituting the fluidized bed 14 or when new waste 18 is supplied into the furnace body 20 by the waste supply unit 60. (That is, toward the second region ua ₂ of the fluidized bed 14). Then, since the second region ua ₂ is at a high temperature, the waste 18 moved from the first region ua ₁ side is sufficiently gasified to generate a combustible gas. Thereby, intermittent and rapid generation | occurrence | production of combustible gas is suppressed, and generation | occurrence | production of the said gas can be stabilized.

Moreover, the temperature of each said area | region of the fluidized bed 14 is adjusted by adjusting the air ratio of the fluidization gas supplied to each area | region of the fluidized bed 14 in the direction which goes from the front wall 24 to the rear wall 25 (or discharge port 29). Because of the adjustment, fluidity abnormalities (such as local fluidity defects in the fluidized bed 14) are less likely to occur in the fluidized bed 14. That is, the flow rate of the fluidized gas supplied to the fluidized bed 14 is maintained while maintaining a good flow state of the fluidized particles 12 in each region by sufficiently maintaining the flow rate of the fluidized gas supplied to each region of the fluidized bed 14. The temperature of each region is adjusted by adjusting the air ratio (ie, oxygen concentration). In addition, in each of the first region ua ₁ , the second region ua ₂ , and the third region ua ₃ , by detecting the temperatures of the upper position and the lower position that are spaced apart from each other, a flow failure occurs in the area. This can be reliably detected.

  In addition, since the upper surface 21a of the bottom wall 21 of the furnace body 20 is inclined so as to become lower toward the discharge port, incombustibles, carbides, and the like in the waste 18 sinking to the bottom wall 21 in the fluidized bed 14 are The upper surface 21 a of the bottom wall 21 is lowered toward the discharge port 29. Thereby, the said incombustible material etc. can be easily discharged | emitted from the furnace main body 20. FIG.

  The fluidized bed furnace of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the scope of the present invention.

The temperature sensor 40 disposed in each upper region ua ₁ , ua ₂ , ua ₃ is an intermediate position between the upper position and the lower position in the vertical direction in addition to the position for detecting the temperature between the upper position and the lower position. It may be arranged at a position for detecting the temperature.

Moreover, in the said embodiment, although each temperature sensor 40 is arrange | positioned so that it may arrange in the front-back direction at the same height position at intervals, it is not limited to this. Each temperature sensor 40 may be at a different height for each of the upper regions ua ₁ , ua ₂ , ua ₃ .

  When the wind box is adjacent to the discharge port 29 on both sides before and after the discharge port 29 (on the right side and the left side of the discharge port 29 in FIG. 3), the wind box closest to the discharge port 29 is both of these winds. Insert the box. However, from the viewpoint of suitably controlling the temperature of the fluidized bed 14 as a whole, it is preferable to control the temperature of the upper region in the wind box on the rear side (right side in FIG. 3) of the discharge port 29.

DESCRIPTION OF SYMBOLS 10 Fluidized bed furnace 12 Fluidized particle 14 Fluidized bed 18 Waste 20 Furnace main body 21 Bottom wall 21a Upper surface 24 of a bottom wall Front wall (supply side wall)
29 Discharge port 30 Gas supply part 32 Air box 33 Supply part 40 Temperature sensor (temperature detection part)
50 Control unit 60 Waste supply unit ua ₁ , ua ₂ , ua ₃ upper region (first region, second region, third region)

Claims (4)

A fluidized bed furnace that heats waste and takes out combustible gas from the waste,
A bottom wall that supports the fluidized particles constituting the fluidized bed for heating the waste from below and a side wall that rises from the bottom wall; A discharge port is provided for discharging the non-combustible material in the waste together with the fluidized particles, and the top surface of the bottom wall is disposed on the top surface of the bottom wall so that the non-combustible material descends on the top surface of the bottom wall toward the discharge port. A furnace body that slopes down toward the outlet;
A gas supply unit for fluidizing the fluidized particles by blowing fluidized gas from the bottom wall of the furnace body to the fluidized particles;
A plurality of temperature detectors for detecting the temperature of the fluidized bed;
A control unit for controlling the gas supply unit;
A waste supply unit that supplies the waste to a region adjacent to the supply-side side wall on the fluidized bed from a supply-side side wall that is located on the opposite side to the discharge port across the center position of the bottom wall among the side walls. And comprising
The gas supply unit extends below the bottom wall in a direction orthogonal to the direction from the supply side wall toward the discharge port, and fluidizes the fluidized particles from a predetermined position in the orthogonal direction. A plurality of wind boxes for blowing gas, and a supply unit that supplies the fluidized gas to each of these wind boxes and can adjust the air ratio of the fluidized gas supplied to each of the wind boxes, Have
The plurality of wind boxes are arranged in a direction from the supply side wall toward the discharge port,
The plurality of temperature detection units are configured to detect temperatures of an upper position and a lower position spaced vertically in a first region overlapping with a first wind box closest to the supply side wall in the fluidized bed in a vertical direction. In addition to detecting, the temperature of the second wind box closest to the outlet in the fluidized bed or the temperature between the upper and lower positions spaced vertically in the second area overlapping the outlet in the vertical direction is detected. Placed in each possible position,
The control unit is supplied to each wind box by the supply unit so that the temperature of the fluidized bed increases from the first region toward the second region based on the temperature detected by each temperature detection unit. The fluidized bed furnace is characterized by adjusting the air ratio of the fluidized gas. The fluidized bed furnace according to claim 1,
Between the first region and the second region in the fluidized bed, the plurality of temperature detection units are respectively disposed at positions where temperatures can be detected at predetermined intervals in a direction from the supply side wall toward the discharge port. Fluidized bed furnace. The fluidized bed furnace according to claim 2,
Each temperature detection unit arranged between the first region and the second region overlaps each wind box arranged between the first wind box and the second wind box in the vertical direction. Fluidized bed furnaces that are placed at positions where the temperature of the area can be detected. In the fluidized bed furnace according to claim 3,
In each region that overlaps with the wind box between the first region and the second region in the vertical direction, each temperature detection unit can detect the temperature between the upper position and the lower position that are spaced vertically. Each in fluidized bed furnace.

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