JP5875720B1 - Waste incinerator boiler and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the radiant heat transfer from the flame on the stoker and the supply amount of primary air even if the amount of waste supply and properties fluctuate and the flame on the stoker changes greatly, the outlet side of the superheater The temperature of the superheated steam can be controlled to be constant at all times, and the radiant heat from the flame can be received effectively. SOLUTION: The primary air A1 is dividedly supplied under the stalker 5 divided in the flow direction of the waste B, the waste B on the stalker 5 is sequentially dried and burned, and steam is generated in the boiler 2 by the generated combustion exhaust gas. S is generated, and the temperature of the steam S is reduced by the temperature reducing device 21 and the temperature is adjusted. Then, the steam S is further heated by the superheater 20 disposed at the downstream position of the stalker 5 to be superheated steam S ′. The waste B incinerator boiler includes a radiation control device 49 that controls the radiation heat transfer from the flame F on the stoker 5 to increase or decrease the amount of heat received by the superheater 20. [Selection] Figure 1

Description

  The present invention is a waste incinerator boiler equipped with an incinerator for incinerating wastes such as general waste, industrial waste, sludge and the like, and a boiler attached to this incinerator to generate steam by combustion exhaust gas, The primary air is dividedly supplied under the stalker divided in the flow direction of the waste to incinerate the waste on the stalker, and steam is generated in the boiler by the generated combustion exhaust gas. Amount of waste supplied in connection with improvement of waste incinerator boiler and its control method in which the temperature is adjusted by adjusting the temperature and then further heated by a superheater located downstream of the stoker to produce superheated steam. The temperature of superheated steam on the outlet side of the superheater is always constant by controlling the radiation heat transfer from the flame on the stoker and the supply of primary air even if the properties change and the flame on the stoker changes. If you can control To, to a waste incinerator boiler and control method thereof to allow effective heat radiation heat from the flame.

  In general, a waste incinerator boiler burns waste such as municipal waste and sludge in an incinerator, recovers the combustion exhaust gas generated by the combustion of the waste in the boiler, and generates superheated steam in the boiler superheater. ing.

  By the way, conventional waste incinerator boilers may cause high temperature corrosion in boiler superheaters due to chlorine contained in combustion exhaust gas and metals contained in fly ash. The temperature of the superheated steam was such that the high temperature corrosion of the superheater could be reduced and the fly ash contained in the combustion exhaust gas was not melted, and the temperature of the superheated steam could not be raised to 400 ° C or higher. As a result, the operating conditions of the boiler are restricted, which hinders efficient heat recovery.

  Since the superheater is usually installed at the downstream side of the radiation zone of the boiler, the combustion exhaust gas temperature on the inlet side of the superheater is about 650 ° C., and the temperature of the superheated steam on the outlet side of the superheater is The temperature difference with the temperature of the combustion exhaust gas is not so large at about 350 ° C., and the heat transfer area of the superheater is set large due to heat transfer inhibition due to the adhesion and deposition of fly ash.

  Moreover, the arrangement of the superheater tubes of the superheater is a grid-like arrangement in consideration of prevention of blockage of the superheater because the combustion exhaust gas contains fly ash, and the main form of heat transfer to the superheater Is convective heat transfer.

  The temperature of the superheated steam can be raised to 400 ° C or higher. In this case, the superheater is made of stainless steel, or the surface of the superheater of the superheater is sprayed with corrosion resistant steel such as Inconel. In other words, it has to be able to withstand high-temperature corrosion by applying a thick layer and a build-up, which requires expensive materials and processing, resulting in high costs.

  On the other hand, in a waste incinerator boiler, a superheater is installed in a position where it does not come into contact with corrosive combustion exhaust gas as much as possible, and the technology that obtains superheated steam using the radiant heat of the combustion flame in the incinerator Is known (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).

  That is, the waste incinerator boiler (garbage incinerator) disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 7-190325) is located at the upper position on the downstream side of the stoker of the incinerator where the corrosive gas is hardly generated in the superheater. In order to obtain superheated steam using the radiant heat from the combustion flame on the stoker, keep the temperature of the superheated steam constant by the gas combustor (combustion superheater) provided outside the incinerator. Therefore, it is possible to heat up to a temperature higher than the limit temperature at which high-temperature corrosion occurs, and high-temperature and high-pressure superheated steam can be obtained to increase the amount of heat recovery and improve power generation efficiency.

  Further, a waste incinerator boiler (garbage incinerator) disclosed in Patent Document 2 (Japanese Patent Application Laid-Open No. 9-79555) is located at an upper position on the downstream side of a stoker of an incinerator that hardly generates corrosive gas in a superheater. Because it is used to obtain superheated steam using the radiant heat from the combustion flame on the stoker, and the temperature of the superheated steam is kept constant by a burner (fuel injection device) provided on the wall of the incinerator In addition, it can be heated to a temperature higher than the limit temperature at which high temperature corrosion occurs, and high temperature and high pressure superheated steam can be obtained, so that the amount of heat recovery can be increased and the power generation efficiency can be improved. In addition, since the steam can be superheated in the same furnace without providing an external gas combustor, fuel consumption can be further reduced.

  Further, in a waste incinerator boiler disclosed in Patent Document 3 (Japanese Patent Laid-Open No. 9-60828), a superheater is installed at an upper position on the downstream side of a stoker of an incinerator where almost no corrosive gas is generated. The superheated steam is obtained by using the radiant heat from the upper combustion flame, and the temperature of the superheated steam is kept constant by spraying water from the temperature reducing device to the inlet of the superheater. A constant high temperature and high pressure superheated steam can be obtained without causing corrosion.

  However, the waste incinerator boilers described in Patent Documents 1 and 2 are both expensive because they require an external fuel such as a gas combustor, a burner, and gas to keep the temperature of the superheated steam constant. There was a problem that the running cost would increase with the equipment.

  In addition, the waste incinerator boilers described in Patent Documents 1 and 2 have no countermeasures against a high temperature state (in the case where the amount of combustion heat of garbage is high) generated as a result of burning garbage with unstable properties. Not. In other words, when the temperature inside the furnace becomes an unexpectedly high temperature, the superheated steam becomes high temperature and pressure and becomes unstable, and overload is generated in the power generation equipment and heat utilization equipment, so that the energy collected at the corner is recovered. It may happen that you have to discard it.

  Furthermore, in the waste incinerator boiler described in Patent Document 3, the amount of water sprayed is controlled when the amount of combustion and the calorific value of the dust vary greatly, and the size and brightness of the combustion flame on the stoker vary greatly. There is a problem that the temperature of the superheated steam cannot be kept constant only by itself.

JP-A-7-190325 JP-A-9-79555 Japanese Patent Laid-Open No. 9-60828

  The present invention has been made in view of such problems, and the purpose of the present invention is to reduce the amount of waste from the flame on the stoker even if the amount of supplied waste and the properties of the waste fluctuate and the flame on the stoker changes. A waste incinerator boiler that can constantly control the temperature of superheated steam on the outlet side of the superheater by controlling the amount of radiant heat transfer and primary air supply, and can effectively receive the radiant heat from the flame, and It is in providing the control method.

  In order to achieve the above object, the first invention of the present invention is generated by dividing and supplying the primary air under the stoker divided into a plurality of parts in the waste flow direction to sequentially dry and burn the waste on the stoker. Dispose of steam generated by combustion exhaust gas in a boiler, and the temperature of the steam is reduced by a temperature reducing device and the temperature is adjusted, and then further heated by a superheater disposed downstream of the stalker to be superheated. The incinerator boiler is characterized by including a radiation control device that controls the radiation heat transfer from the flame on the stoker to increase or decrease the amount of heat received by the superheater.

  According to a second aspect of the present invention, in the first aspect, the radiation control device can be moved up and down between the flame on the stalker and the superheater at a position downstream of the stalker or moved in the width direction of the stalker. It is characterized in that it is provided with a radiation control plate that is freely arranged and blocks the radiant heat from the flame on the stoker to increase or decrease the amount of heat received by the superheater, and a drive unit that moves and adjusts the radiation control plate.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the waste incinerator boiler distributes the primary air dividedly supplied below the stoker according to the size and brightness of the flame on the stoker. And a primary air supply device that can change the position of the flame on the stoker by controlling the above.

  According to a fourth aspect of the present invention, in the third aspect, the primary air supply device is connected in a branched manner to a plurality of lower stalker hoppers respectively disposed under the divided stalkers, and the primary air is provided below the stalker. A plurality of primary air supply ducts, a primary air blower connected to the primary air supply duct, and a plurality of primary air supply units that are provided at the branch portions of the primary air supply duct to adjust the supply amount of primary air supplied to the bottom of the stoker And the primary air supply amount of the branch portion of the primary air supply duct are measured, and each damper is adjusted so that the primary air supply amount of the branch portion of the primary air supply duct becomes a predetermined amount based on the measurement result. It is characterized by comprising an air volume controller to be controlled and a control device that controls each air volume controller so that the distribution of the primary air to the branch portion of the primary air supply duct becomes a predetermined distribution.

  According to a fifth aspect of the present invention, in the first aspect, the second aspect, the third aspect, or the fourth aspect, the stoker is disposed before the drying stage and the downstream position of the drying stage. And a rear combustion stage disposed downstream of the front combustion stage, and a rear combustion stage disposed downstream of the rear combustion stage.

  According to a sixth aspect of the present invention, in the first aspect, the temperature reducing device includes a water supply pipe that sprays water into a steam supply pipe that guides the steam to the superheater, and a control valve interposed in the water supply pipe. And a temperature controller that detects the temperature of the superheated steam on the outlet side of the superheater and controls the control valve so that the temperature of the superheated steam becomes a predetermined temperature based on the detected temperature. It is characterized in that it is configured as a temperature device.

  According to a seventh aspect of the present invention, in the first aspect or the second aspect, the superheater is provided with superheater tubes arranged in a staggered manner by turning at least once, and the superheaters of each row are provided. The tubes are characterized by being arranged out of line with the flame on the stoker.

  According to an eighth aspect of the present invention, in the seventh aspect, the interval between adjacent superheater tubes in each row is set to be 1 to 2 times the number of turns of the superheater tube × the diameter of the superheater tube. There is.

  A ninth aspect of the present invention is a method for controlling a waste incinerator boiler according to any one of the first to eighth aspects, wherein the temperature generated by reducing the temperature of steam generated in the boiler by a temperature reducing device. By adjusting the temperature, the temperature of the superheated steam at the outlet side of the superheater is kept constant, and the size and brightness of the flame on the stoker changes due to changes in the amount and properties of waste. When the temperature of the heater cannot be controlled at a constant level, the radiation control device controls the radiation heat transfer from the flame on the stalker according to the size and brightness of the flame on the stalker to increase or decrease the amount of heat received by the superheater. It is characterized in that the temperature of the superheated steam is kept constant by a combination of control and control by the radiation control device.

  According to a tenth aspect of the present invention, in the ninth aspect of the invention, the amount of heat generated from the waste is reduced, the size and brightness of the flame on the stoker is reduced, and the temperature of the superheated steam is controlled to be constant only by the temperature reducing device. If this is not possible, the radiation control plate of the radiation control device is moved and adjusted to increase the area of the heat receiving surface of the superheater to increase the amount of heat received by the superheater. When the size and brightness of the heater rises and the temperature of the superheated steam cannot be controlled with just the temperature reducing device, the radiation control plate of the radiation control device is moved and adjusted to reduce the area of the heat receiving surface of the superheater. It is characterized by reducing the amount of heat received.

  In an eleventh aspect of the present invention, in the ninth aspect or the tenth aspect of the present invention, the amount of heat generated by the waste is reduced, the size and brightness of the flame on the stoker is reduced, and only the temperature reducing device and the radiation control device are provided. Then, when the temperature of superheated steam cannot be controlled at a constant level, the primary air supply device increases the primary air near the downstream side of the stalker, and moves the flame position on the stalker in the direction approaching the superheater, so that the amount of heat received by the superheater In addition, when the calorific value of the waste rises and the size and brightness of the flame on the stoker rises, and the temperature of the superheated steam cannot be controlled with just the temperature reducing device and the radiation control device, the primary air supply device Is characterized in that the primary air near the upstream side of the stalker is increased and the position of the flame on the stalker is moved away from the superheater to reduce the amount of heat received by the superheater.

  According to the present invention, the temperature of the steam generated in the boiler is controlled by the temperature reducing device, and the radiation control device blocks the radiant heat from the flame according to the size and brightness of the flame on the stoker, thereby reducing the amount of heat received by the superheater. Since the amount is increased or decreased, the temperature of the superheated steam on the outlet side of the superheater can be constantly controlled even when the supply amount and properties of the waste fluctuate and affect the flame on the stoker.

  Further, according to the present invention, in addition to the control by the temperature reducing device and the control by the radiation control device, the primary air amount dividedly supplied below the stoker is controlled to change the position of the flame on the stoker, and the overheating by the flame radiation Since the amount of heat received by the heater is changed, the temperature of the superheated steam on the outlet side of the superheater is constantly controlled even if the amount of waste supplied and the properties of the waste fluctuate greatly and affect the flame on the stoker. can do. Moreover, because the position of the flame on the stoker can be changed by controlling the primary air volume, even when the flame is small, the superheater can effectively receive the radiant heat from the flame by bringing the flame closer to the superheater. Can do.

  Furthermore, according to the present invention, the superheater is arranged at a downstream side position of the stoker where almost no corrosive gas is generated, and the superheater tubes of the superheater are arranged in a staggered manner so as to line up the flames on the stoker. Therefore, the high temperature corrosion of the superheater can be prevented, and the heat transfer surface of the superheater tube can effectively function to secure a predetermined heat receiving amount.

  In addition, according to the present invention, since the radiation control plate of the radiation control device is disposed at the downstream side position of the stoker that hardly generates corrosive gas, an expensive material excellent in corrosion resistance is provided on the radiation control plate. It is not necessary, and cost reduction can be achieved.

1 is a schematic system diagram of a waste incinerator boiler according to an embodiment of the present invention. It is a graph which shows the relationship between the water spray amount of a temperature reducing apparatus, and a control signal. It is explanatory drawing which shows distribution of the primary air quantity under a stalker. The example of arrangement | positioning of the superheater tube of a superheater is shown, (a) is a schematic cross-sectional view of a superheater, (b) is a schematic front view of a superheater. The other example of arrangement | positioning of the superheater tube of a superheater is shown, (a) is a schematic cross-sectional view of a superheater, (b) is a schematic front view of a superheater.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a waste incinerator boiler according to an embodiment of the present invention. The waste incinerator boiler includes an incinerator 1 that incinerates waste B such as municipal waste and sludge, and an incinerator 1. And a boiler 2 that recovers heat from the combustion exhaust gas.

  That is, as shown in FIG. 1, the incinerator 1 includes a furnace body 3 composed of a furnace wall, a waste charging hopper 4 into which the waste B is charged, a stalker 5 for burning the waste B, and a bottom of the stalker 5 A hopper 6 below the stalker disposed in the hopper, a waste supply pusher 7 for supplying the waste B onto the stalker 5, a primary combustion chamber 8 formed above the stalker 5, and a formation above the primary combustion chamber 8. Secondary combustion chamber 9, combustion exhaust gas outlet 10 for discharging combustion exhaust gas, ash outlet 11 for discharging incineration ash, cooling water tank 12 for cooling the incineration ash, and water-sealed conveyor for conveying the incineration ash 13, a primary air supply device 14 that supplies primary air A <b> 1 below the stoker 5, a secondary air supply device 15 that supplies secondary air A <b> 2 to the secondary combustion chamber 9, and radiation from the flame F on the stoker 5. Receiving heat of superheater 20 of boiler 2 by controlling heat transfer And a radiation control device 49 such as to increase or decrease the.

  On the other hand, as shown in FIG. 1, the boiler 2 recovers heat from the combustion exhaust gas generated by the combustion of the waste B, heats boiler feed water to generate steam S, and further superheats the steam S to generate high temperature and pressure. Superheated steam S ′, a drum 16, a large number of water pipes 17 arranged on the wall surface of the furnace, the superheaters 18 to 20 having the steam S as the superheated steam S ′, and the superheaters 18 to And a temperature reducing device 21 for adjusting the temperature by reducing the temperature of the steam S supplied to 20.

  The stoker 5 includes a drying stage 5a, a front combustion stage 5b disposed downstream of the drying stage 5a, a rear combustion stage 5c disposed downstream of the front combustion stage 5b, And a post-combustion stage 5d disposed downstream of the combustion stage 5c, and lower stoker hoppers 6 are disposed below the respective stages 5a to 5d. Although not shown, each stage 5a to 5d constituting the stoker 5 is formed by alternately arranging movable grate and fixed grate, and each movable grate is fixed in the front-rear direction by a driving device such as a cylinder. The waste B on the stalker 5 is moved forward from the upstream side toward the downstream side (from the left side to the right side in FIG. 1) while being agitated.

  In the above-described embodiment, the stoker 5 is divided into four parts, that is, the drying stage 5a, the front combustion stage 5b, the rear combustion stage 5c, and the rear combustion stage 5d, and the supply place of the primary air A1 is four. In other embodiments, the stoker 5 may be divided into three stages, ie, a drying stage, a combustion stage, and a post-combustion stage, and the supply location of the primary air A1 may be three.

  The primary air supply device 14 is connected to the primary air supply duct 22 and the primary air supply duct 22, which are branchedly connected to the hoppers 6 below the stalker 5 and supply the primary air A 1 under the stalker 5. The primary air blower 23, the primary air damper 24 that is provided upstream of the primary air supply duct 22 and adjusts the supply amount of the primary air A1, and the supply amount of the primary air A1 in the primary air supply duct 22 An air volume controller 25 for primary air that controls the primary air damper 24 so that the supply amount of the primary air A1 becomes a predetermined amount based on the measurement result, and a branch portion of the primary air supply duct 22 is provided. The plurality of dampers 26 to 29 for adjusting the supply amount of the primary air A1 supplied to the respective stages 5a to 5d of the stoker 5 and the supply of the primary air A1 at the branch portion of the primary air supply duct 22 Air flow controllers 30 to 33 for controlling the dampers 26 to 29 so that the supply amount of the primary air A1 at the branching portion of the primary air supply duct 22 becomes a predetermined amount based on the measurement results, and the primary air And a control device 34 that controls each of the air volume controllers 30 to 33 so that the distribution of the primary air A1 becomes a predetermined distribution based on the control signal from the controller 25 for control, and the control signal from the control device 34 By controlling the dampers 26 to 29 by the air volume controllers 30 to 33 based on the above, the ratio of the primary air A1 distributed and supplied to the stages 5a to 5d of the stoker 5 can be adjusted to a predetermined ratio. It has become.

  The secondary air supply device 15 includes a secondary air supply pipe 36 connected to a secondary air supply port 35 provided on the furnace wall of the secondary combustion chamber 9, and a secondary air connected to the secondary air supply pipe 36. An air blower 37, a secondary air damper 38 interposed in the secondary air supply pipe 36 for adjusting the supply quantity of the secondary air A2, and a supply quantity of the secondary air A2 in the secondary air supply pipe 36 And a secondary air volume controller 39 for measuring and controlling the secondary air damper 38 based on the measurement result, and blowing the secondary air A2 at normal temperature or preheated into the secondary combustion chamber 9. It is like that.

  The combustion air supplied to the primary air supply device 14 and the secondary air supply device 15 is measured for oxygen concentration by an oxygen concentration measuring device 40 disposed on the combustion exhaust gas outlet 10 side, and this oxygen concentration is kept constant. Thus, the supply amount of the primary air A1 and the supply amount of the secondary air A2 are determined, and based on the detection signal from the oxygen concentration measuring device 40, the control device 41 controls the primary air flow rate controllers 25 and 2. A predetermined amount of primary air A1 and secondary air A2 are supplied to the incinerator 1 by controlling the air volume controllers 39 for the secondary air.

  In this embodiment, the total air amount of the primary air A1 and the secondary air A2 is set to about 1.3 in the air ratio. The supply amount of the primary air A1 supplied below the stoker 5 is 1.0 in terms of the primary air ratio (primary air amount / theoretical air amount), and is supplied to each stage 5a to 5d of the stoker 5. The amount of primary air A1 supplied is such that the drying stage 5a has a ratio of 0.2, the front combustion stage 5b is 0.3, the rear combustion stage 5c is 0.3, and the rear combustion stage 5d is 0.2. It has been. The ratio of the primary air A1 is a ratio when the temperature of the superheated steam S ′ on the outlet side of the superheater 20 can be controlled to be constant by the temperature reducing device 21, and the ratio is reduced by changing the supply amount and properties of the waste B. When the temperature of the superheated steam S ′ cannot be controlled to be constant only by the temperature device 21, the ratio is changed.

  In the above embodiment, the supply amount of the primary air A1 is 1.0 as the primary air ratio. However, in other embodiments, the supply amount of the primary air A1 is 0.9 to 1 in terms of the primary air ratio. .1 may be varied. In this case, the supply amount of the secondary air A2 is also changed in the range of 0.2 to 0.4 in terms of the secondary air ratio.

  The superheaters 18 to 20 are divided into two locations, and are arranged in a flue connected to the combustion exhaust gas outlet 10 of the incinerator 1 to superheat the steam S and two superheaters 18 and 19. And a superheater that is disposed downstream of the stoker 5 and between the post-combustion stage 5d and the front wall 3a of the incinerator 1 and further superheats the superheated steam S ′ that has passed through the two superheaters 18 and 19. 20.

  Two superheaters 18 and 19 arranged in the flue are connected to superheater pipes 18a and 19a arranged in a grid pattern and headers 18b and 19b connected to the superheater pipes 18a and 19a in the same manner as conventionally known. Thus, the steam S flowing in the superheat pipes 18a and 19a is superheated by the combustion exhaust gas flowing in the flue. The reason why the superheat pipes 18a, 19a are arranged in a grid pattern in the flue is that the possibility of clogging by dust in the combustion exhaust gas becomes lower than when the superheat pipes 18a, 19a are arranged in a staggered pattern. .

  On the other hand, the superheater 20 disposed on the downstream side of the stalker 5 has a superheated pipe 20a that is turned at least once by bending one pipe in a vertical orientation and in the width direction of the incinerator 1 (on the stalker 5). Are arranged in a direction perpendicular to the flow direction of the waste B, and both ends of each superheater tube 20a are connected to the header 20b. Each superheater tube 20a is viewed in a cross-sectional view. They are arranged in a staggered manner so as not to line up with the flames F on the stoker 5. The superheater tubes 20a are arranged in a staggered manner between the post-combustion stage 5d of the stalker 5 and the front wall 3a of the incinerator 1 because the superheater tubes 20a are arranged at a position where there is little adhering dust and is blocked by dust. This is because it does not occur, and it is difficult for the upstream superheater tube 20a to prevent flame radiation to the downstream superheater tube 20a, and the amount of heat received by the superheater tube 20a is improved.

  The U-shaped turn portion of each superheater tube 20a requires an inter-core P that is twice or more the outer diameter D of the superheater tube 20a. Further, the interval W between adjacent superheater tubes 20a in each row is required to be equal to or greater than the outer diameter D of the superheater tube 20a in order to receive flame radiation. If the interval W is too large, the number of superheater tubes 20a is increased in a limited space. Since it becomes impossible to arrange and a predetermined amount of heat received cannot be secured, the number of turns n of the superheater tube 20 x 1 to 2 times the diameter D of the superheater tube 20a is set.

  4 and 5 show an arrangement example of the superheater tubes 20a of the superheater 20, and FIG. 4 shows a plurality of superheater tubes 20a that are turned only once in a vertical orientation and in the width direction of the incinerator 1. FIG. 5 shows a plurality of superheated tubes 20 a that are turned a plurality of times in a vertical orientation and in the width direction of the incinerator 1.

  In addition, in said embodiment, although superheater 18-20 was divided | segmented and arrange | positioned in two places, in other embodiment, superheater 18-20 is arrange | positioned only in the downstream position of the stoker 5. Anyway. In the above embodiment, a plurality of superheat tubes 20 a are arranged in the width direction of the incinerator 1. However, in another embodiment, a plurality of superheat tubes 20 a are arranged in the flow direction of the waste B on the stoker 5. You may do it.

  The temperature reducing device 21 prevents the temperature of the superheated steam S ′ on the outlet side of the superheater 20 from fluctuating even when the heat generation amount and the generated steam amount fluctuate due to the supply amount and properties of the waste B. The temperature of the steam S ′ is always kept constant.

  That is, the temperature reducing device 21 is interposed in the water supply pipe 43 and the water supply pipe 43 for spraying water C into the steam supply pipe 42 for introducing the steam to the superheater 20 disposed at the downstream side position of the stoker 5. Temperature control for detecting the temperature of the control valve 44 and the superheated steam S ′ on the outlet side of the superheater 20 and controlling the control valve 44 so that the temperature of the superheated steam S ′ becomes a predetermined temperature based on the detected temperature. The temperature of the superheated steam S ′ on the outlet side of the superheater 20 is controlled by controlling the amount of water C sprayed in the steam supply pipe 42. It can be kept constant.

  The radiation control device 49 controls the radiation heat transfer from the flame F to the downstream side position of the stalker 5 even when the size or brightness of the flame F on the stalker 5 changes depending on the supply amount or properties of the waste B. The amount of heat received by the arranged superheater 20 is increased or decreased to keep the temperature of the superheated steam S ′ constant.

  That is, the radiation control device 49 is inserted into and supported by the ceiling wall 3b of the furnace body 3 so as to be movable up and down, and is disposed at a position downstream of the stoker 5 and between the flame F on the stoker 5 and the superheater 20. A radiation control plate 50 that blocks the radiant heat from the flame F on the stoker 5 and increases or decreases the amount of heat received by the superheater 20, and a drive unit 51 that includes a cylinder or the like that moves and adjusts the radiation control plate 50 so as to be movable up and down. The amount of heat received by the superheater 20 is increased or decreased by moving the radiation control plate 50 up and down by the drive device 51 to increase or decrease the area of the heat receiving surface of the superheater 20.

  In this embodiment, the height of the radiation control plate 50 of the radiation control device 49 is adjusted in three steps in the vertical direction by the drive device 51, and the normal position is the majority of the superheater 20 (superheater 20. Is located at a position where the radiant heat from the flame F on the stoker 5 is received (position e in FIG. 1), and the position and the brightness of the flame F on the stoker 5 are increased. Is at a position where the lower half of the superheater 20 receives radiant heat from the flame F (position f in FIG. 1), and further, the position when the size and brightness of the flame F on the stoker 5 are reduced is overheated. The entire vessel 20 is in a position where it receives the radiant heat from the flame F (position g in FIG. 1).

  In the above-described embodiment, the height of the radiation control plate 50 of the radiation control device 49 is adjusted in three steps in the vertical direction by the drive device 51. However, in other embodiments, the radiation control plate 50 is driven. The height may be adjusted steplessly in the vertical direction by the device 51. Moreover, in said embodiment, the radiation control board 50 is inserted and supported by the ceiling wall 3b of the furnace main body 3 so that raising / lowering is possible, and the area of the heat receiving surface of the superheater 20 is increased / decreased by changing the height of the radiation control board 50. However, in another embodiment, the radiation control plate 50 is disposed so as to be movable and adjustable in the width direction of the stalker 5 (the front-rear direction in FIG. 1), and the radiation control plate 50 is connected to the stalker 5 by the driving device 51. The area of the heat receiving surface of the superheater 20 may be increased or decreased by adjusting the movement in the width direction. In this case, the radiation control plate 50 may be moved and adjusted stepwise, or the radiation control plate 50 may be moved and adjusted steplessly.

  In the waste incinerator boiler, the size and brightness of the flame on the stoker 5 change due to changes in the supply amount and properties of the waste B, and the superheated steam S ′ is generated only by the water spray control by the temperature reducing device 21. When the temperature cannot be controlled to be constant, the temperature of the superheated steam S ′ on the outlet side of the superheater 20 is appropriately combined with the primary air amount control by the primary air supply device 14 and the position control of the radiation control plate 50 by the radiation control device 49. Is kept constant.

  That is, the temperature control of the superheated steam S ′ on the outlet side of the superheater 20 is performed by combining the water spray control by the temperature reducing device 21 and the position control of the radiation control plate 50 by the radiation control device 49 on the outlet side of the superheater 20. The temperature of the superheated steam S ′ may be kept constant, or water spray control by the temperature reducing device 21, primary air amount control by the primary air supply device 14, and position control of the radiation control plate 50 by the radiation control device 49. And the temperature of the superheated steam S ′ on the outlet side of the superheater 20 may be kept constant.

  Next, a method for controlling the waste incinerator boiler described above will be described.

  Waste B such as municipal waste and sludge charged into the waste input hopper 4 is supplied onto a stoker 5 in the furnace by a waste supply pusher 7. Waste B supplied onto the stalker 5 is upstream of the drying stage 5a, the front combustion stage 5b, the rear combustion stage 5c, and the rear combustion stage 5d on the stalker 5 by the longitudinal movement of a movable grate (not shown). It moves while being dried, combusted and post-combusted from the downstream to the downstream side, and becomes complete ash, which is discharged from the ash outlet 11 to the outside of the furnace.

  At this time, the combustion of the waste B mainly occurs in the front combustion stage 5b (position a in FIG. 1), and a vigorous flame F is formed on the front combustion stage 5b. The combustion air is measured for oxygen concentration by an oxygen concentration measuring device 40 disposed on the combustion exhaust gas outlet 10 side, and the supply amount of the primary air A1 and the supply of the secondary air A2 so that the oxygen concentration is kept constant. The amount is determined. Control of the air volume of the primary air A1 and the secondary air A2 is performed by controlling the primary air volume controller 25 and the secondary air volume controller 39 by the control device 41 based on the detection signal from the oxygen concentration measuring device 40, respectively. Is done by doing. Furthermore, the supply amount of the primary air A1 is sent at a ratio determined to the drying stage 5a, the front combustion stage 5b, the rear combustion stage 5c, and the rear combustion stage 5d of the stoker 5, and in this example, the drying stage 5a Is 0.2, the front combustion stage 5b is 0.3, the rear combustion stage 5c is 0.3, and the rear combustion stage 5d is 0.2.

  The flue gas in the furnace generated by the combustion of the waste B passes through the primary combustion chamber 8, the secondary combustion chamber 9, the flue gas outlet 10 and the flue, during which heat is recovered by the boiler 2 and the exhaust gas treatment. It is purified by a device (not shown) and released into the atmosphere.

  The steam S generated by the heat recovery in the boiler 2 is sequentially guided to the superheaters 18 and 19 disposed in the flue by the steam supply pipe 42 and the superheater 20 disposed downstream of the stalker 5 at 450 ° C. To superheated steam S ′. The 450 ° C. superheated steam S ′ is sent to the power generation facility including the steam turbine 46 and the generator 47 through the steam supply pipe 42, and the steam turbine 46 is rotated to generate power. Reference numeral 48 denotes an exhaust vapor condenser.

  In the boiler 2, the amount of generated steam varies due to fluctuations in the supply amount and properties of the waste B, and the temperature of the superheated steam S ′ on the outlet side of the superheater 20 disposed downstream of the stoker 5 varies. Therefore, the temperature of the superheated steam S ′ on the outlet side of the superheater 20 is kept constant by spraying water C onto the steam supply pipe 42 on the inlet side of the superheater 20 and adjusting the temperature by the temperature reducing device 21. I have to.

  That is, the temperature of the superheated steam S ′ on the outlet side of the superheater 20 detects the temperature of the superheated steam S ′ on the outlet side of the superheater 20, and the temperature of the superheated steam S ′ is determined to be a predetermined temperature based on this detected temperature. The control valve 44 is controlled by the temperature controller 45 so as to be (450 ° C.), and the temperature is adjusted by changing the spray amount of the water C. As shown in the graph of FIG. 2, the spray amount of the water C is controlled. The width is within the range (c to d).

  By the way, the amount of waste B varies depending on the day and month, and if the size and brightness of the flame on the stoker 5 fluctuate greatly, the control range of the waste B can be controlled only by the water C spray control. In some cases, the amount of water spray does not fall within the range (water spray amount c to d), and the temperature of the superheated steam S ′ on the outlet side of the superheater 20 may not be kept constant.

  In this case, the amount of water C sprayed by the temperature reducing device 21 is controlled by controlling the radiation control device 49 to increase or decrease the area of the heat receiving surface of the superheater 20 to increase or decrease the amount of heat received by the superheater 20. Falls within the range of the control width, and the temperature of the superheated steam S ′ on the outlet side of the superheater 20 can be kept constant.

  For example, when the supply amount or nature of the waste B changes, the calorific value decreases, and the size or brightness of the flame F on the stoker 5 (on the front combustion stage 5b) decreases, the temperature reducing device is controlled by the control signal a. Even if the water spray amount by 21 is reduced to the position c in the graph of FIG. 2, the temperature of the superheated steam S ′ on the outlet side of the superheater 20 is lowered, and the temperature of the superheated steam S ′ cannot be kept constant.

  Therefore, when the control signal of the temperature reducing device 21 reaches the position a in the graph of FIG. 2, the radiation control device 49 is controlled, and the position of the radiation control plate 50 is changed from the position e to g shown in FIG. The position rises to increase the area of the heat receiving surface of the superheater 20. Then, the amount of heat received by the superheater 20 increases. As a result, the water spray control of the temperature reducing device 21 falls within the control range (water spray amount cd), and the temperature of the superheated steam S ′ can be kept constant.

  On the other hand, when the supply amount and properties of the waste B fluctuate and the calorific value increases and the size and brightness of the flame F on the stoker 5 (on the front combustion stage 5b) increase, the temperature reducing device is controlled by the control signal b. Even if the water spray amount by 21 is increased to the position of d in the graph of FIG. 2, the temperature of the superheated steam S ′ on the outlet side of the superheater 20 rises, and the temperature of the superheated steam S ′ cannot be kept constant.

  Therefore, when the control signal of the temperature reducing device 21 reaches the position b in the graph of FIG. 2, the radiation control device 49 is controlled, and the position of the radiation control plate 50 is changed from the position e to f shown in FIG. The position is lowered to reduce the area of the heat receiving surface of the superheater 20. Then, the amount of heat received by the superheater 20 is reduced. As a result, the water spray control of the temperature reducing device 21 falls within the control range (water spray amount cd), and the temperature of the superheated steam S ′ can be kept constant.

  The water spray control of the temperature reducing device 21 may not be within the control range (water spray amount is c to d) only by the position control of the radiation control plate 50 by the radiation control device 49. There are times when the temperature of the superheated steam S ′ on the outlet side cannot be kept constant.

  In this case, the primary air supply device 14 is further controlled, the distribution of the primary air A1 dividedly supplied below the stalker 5 is changed, the position of the flame F on the stalker 5 is moved, and the amount of heat received by the superheater 20 is increased. The amount of water C sprayed by the temperature reducing device 21 falls within the range of the control width, and the temperature of the superheated steam S ′ on the outlet side of the superheater 20 can be kept constant.

  That is, in the primary air amount control by the primary air supply device 14, when the control signal of the temperature reducing device 21 reaches the position a in the graph of FIG. 2, the primary air supply device 14 is controlled to distribute the primary air A1. 3 is changed from pattern 1 to pattern 2 so that the drying stage 5a is 0.2, the front combustion stage 5b is 0.3, the rear combustion stage 5c is 0.3, and the rear combustion stage 5d is 0.2. The ratio of the primary air A1 is changed so that the drying stage 5a is 0.2, the front combustion stage 5b is 0.2, the rear combustion stage 5c is 0.4, and the rear combustion stage 5d is 0.2. As a result, the position of the flame F on the stalker 5 moves from the front combustion stage 5b (position a in FIG. 1) to the rear combustion stage 5c (position b in FIG. 1), and the flame F moves to the superheater 20. As a result, the radiation form factor of the heat receiving surface of the flame F and the superheater 20 increases and the amount of heat received by the superheater 20 increases. As a result, the position of the radiation control plate 50 by the radiation control device 49 and the primary air amount control by the primary air supply device 14 allow the water spray control of the temperature reducing device 21 to be within the control range (water spray amount is cd). As a result, the temperature of the superheated steam S ′ can be kept constant.

  When the control signal of the temperature reducing device 21 reaches the position b in the graph of FIG. 2, the primary air supply device 14 is controlled to change the distribution of the primary air A1 from the pattern 1 shown in FIG. The ratio of the primary air A1 in which the stage 5a is 0.2, the front combustion stage 5b is 0.3, the rear combustion stage 5c is 0.3, and the rear combustion stage 5d is 0.2 is 0.2% in the drying stage 5a. 3. Change the front combustion stage 5b to 0.3, the rear combustion stage 5c to 0.2, and the rear combustion stage 5d to 0.2. As a result, the position of the flame F on the stoker 5 moves from the front combustion stage 5b (position a in FIG. 1) to the drying stage 5a (position c in FIG. 1), and the flame F moves from the superheater 20. By moving away, the radiation form factor of the heat receiving surface of the flame F and the superheater 20 decreases, and the amount of heat received by the superheater 20 decreases. As a result, the position of the radiation control plate 50 by the radiation control device 49 and the primary air amount control by the primary air supply device 14 allow the water spray control of the temperature reducing device 21 to be within the control range (water spray amount is cd). As a result, the temperature of the superheated steam S ′ can be kept constant.

  Thus, the waste incinerator boiler is a combination of water spray control by the temperature reducing device 21 and position control of the radiation control plate 50 by the radiation control device 49, or water spray control by the temperature reducing device 21 and primary air. Since the primary air amount control by the supply device 14 and the position control of the radiation control plate 50 by the radiation control device 49 are combined, the supply amount and properties of the waste B greatly fluctuate and affect the flame F on the stalker 5. Even in this case, the temperature of the superheated steam S ′ on the outlet side of the superheater 20 can be controlled to be constant.

  In addition, the waste incinerator boiler can change the position of the flame on the stoker by controlling the amount of primary air, so even if the flame is small, the superheater can be removed from the flame by bringing the flame closer to the superheater. It can receive radiant heat effectively.

  Further, in the waste incinerator boiler, the superheater 20 is disposed at a downstream side position of the stoker 5 where almost no corrosive gas is generated, and the superheater tubes 20a of the superheater 20 are arranged in a staggered manner on the stoker 5. Therefore, the high-temperature corrosion of the superheater 20 can be prevented, and the heat transfer surface of the superheater tube 20a can function effectively to ensure a predetermined amount of heat received. it can.

  In addition, the waste incinerator boiler has a radiation control plate with a radiation control plate disposed downstream of the stoker where almost no corrosive gas is generated. Therefore, an expensive material with excellent corrosion resistance is used for the radiation control plate. It is not necessary, and cost reduction can be achieved.

  In addition, the waste incinerator boiler divides the stoker 5 into four parts, a drying stage 5a, a front combustion stage 5b, a rear combustion stage 5c, and a rear combustion stage 5d, and supplies four primary air A1. Therefore, finer control can be performed, and steam control can be performed without inhibiting stable combustion.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the present invention may be used in combination with an exhaust gas recirculation method in which a part of exhaust gas is mixed with combustion air and supplied.

  1 is an incinerator, 2 is a boiler, 3 is a furnace body, 3a is a front wall, 4 is a waste charging hopper, 5 is a stoker, 5a is a drying stage, 5b is a front combustion stage, 5c is a rear combustion stage, and 5d is Post combustion stage, 6 is a hopper under the stoker, 8 is a waste supply pusher, 8 is a primary combustion chamber, 9 is a secondary combustion chamber, 10 is a combustion exhaust gas outlet, 11 is an ash outlet, 12 is a cooling water tank, and 13 is water Sealed conveyor, 14 is a primary air supply device, 15 is a secondary air supply device, 16 is a drum, 17 is a number of water tubes, 18 to 20 are superheaters, 18a to 20a are superheat tubes, 18b to 20b are headers, 21 is a temperature reducing device, 22 is a primary air supply duct, 23 is a primary air blower, 24 is a primary air damper, 25 is a primary air volume controller, 26 to 29 are dampers, 30 to 33 are air volume controllers, 34 Is a control device, 35 is a secondary air supply port, and 36 is a secondary air Supply pipe, 37 is a secondary air blower, 38 is a secondary air damper, 39 is a secondary air flow rate controller, 40 is an oxygen concentration measuring device, 41 is a control device, 42 is a steam supply pipe, 43 is a water supply Pipe, 44 is a control valve, 45 is a temperature controller, 46 is a steam turbine, 47 is a generator, 48 is a condenser, 49 is a radiation control device, 50 is a radiation control plate, 51 is a drive device, A1 is primary air, A2 is secondary air, B is waste, C is water, S is steam, S 'is superheated steam, D is the diameter of the superheated tube, P is the distance between the cores, W is the space between the superheated tubes, and F is the flame.

Claims (11)

  The primary air is dividedly supplied under the stoker divided in the direction of waste flow, the waste on the stoker is dried and burned sequentially, steam is generated in the boiler by the generated combustion exhaust gas, and the temperature of the steam is reduced. In a waste incinerator boiler where the temperature is reduced by the equipment and the temperature is adjusted, and then further heated by a superheater placed downstream of the stalker to produce superheated steam, the radiant heat transfer from the flame on the stalker is reduced. A waste incinerator boiler comprising a radiation control device that controls and increases or decreases the amount of heat received by a superheater.   The radiation control device is disposed downstream of the stoker and between the flame on the stoker and the superheater so as to be movable up and down or adjustable in the width direction of the stoker so as to block the radiation heat from the flame on the stoker. The waste incinerator boiler according to claim 1, comprising a radiation control plate that increases or decreases a heat receiving amount of the superheater and a drive unit that moves and adjusts the radiation control plate.   The waste incinerator boiler further includes a primary air supply device capable of changing the position of the flame on the stalker by controlling the distribution of the primary air dividedly supplied below the stalker according to the size and brightness of the flame on the stalker. The waste incinerator boiler according to claim 1 or 2, wherein the boiler is a waste incinerator boiler.   The primary air supply device is connected to the primary air supply duct and the primary air supply duct, which are connected in a branched manner to a plurality of hoppers under the stalker respectively arranged under the divided stalker, and supply the primary air under the stalker. Primary air blower, a plurality of dampers that adjust the supply amount of primary air that is interposed in the branch portion of the primary air supply duct and that is supplied under the stoker, and supply of primary air in the branch portion of the primary air supply duct The air volume controller that controls each damper so that the primary air supply amount of the branch portion of the primary air supply duct becomes a predetermined amount based on the measurement result, and the branch air flow controller to the branch portion of the primary air supply duct The waste incinerator boiler according to claim 3, further comprising a control device that controls each air flow controller so that the distribution of the primary air becomes a predetermined distribution.   The stalker is disposed at a drying stage, a front combustion stage disposed downstream of the drying stage, a rear combustion stage disposed downstream of the front combustion stage, and a downstream position of the rear combustion stage. The waste incinerator boiler according to claim 1, 2, 3 or 4, further comprising a post-combustion stage disposed.   The temperature reducing device detects a temperature of the superheated steam on the outlet side of the superheater, a water supply pipe for spraying water into the steam supply pipe for guiding the steam to the superheater, a control valve provided in the water supply pipe, The spray-type temperature reducing device is provided with a temperature controller that controls the control valve so that the temperature of the superheated steam becomes a predetermined temperature based on the detected temperature. The waste incinerator boiler described.   The superheater is provided with superheater tubes arranged in a staggered manner by turning at least once, and the superheater tubes in each row are arranged so as not to line up with the flame on the stoker. The waste incinerator boiler according to claim 1 or 2.   The waste incinerator boiler according to claim 7, wherein an interval between adjacent superheater tubes in each row is set to 1 to 2 times the number of turns of the superheater tube × diameter of the superheater tube.   The method for controlling a waste incinerator boiler according to any one of claims 1 to 8, wherein the temperature of the steam generated in the boiler is reduced by a temperature reducing device and the temperature is adjusted by a temperature reducing device, thereby superheated steam on the outlet side of the superheater. When the temperature and temperature of the flame on the stoker changes due to changes in the amount and properties of waste, and the temperature of the superheated steam cannot be controlled with a temperature-reducing device alone, the radiation control device Controls the radiant heat transfer from the flame on the stalker according to the size and brightness of the flame on the stalker to increase or decrease the amount of heat received by the superheater, and superheated steam by combining the control by the temperature reduction device and the control by the radiation control device A method for controlling a waste incinerator boiler, characterized in that the temperature of the boiler is kept constant.   When the amount of heat generated by the waste decreases and the size and brightness of the flame on the stoker decreases, and when the temperature of the superheated steam cannot be controlled with a temperature-reducing device alone, radiation control is performed so that the heat receiving surface area of the superheater increases. Moving and adjusting the radiation control plate of the equipment increases the amount of heat received by the superheater, and the amount of heat generated from the waste rises, increasing the size and brightness of the flame on the stoker. 10. The amount of heat received by the superheater is reduced by moving and adjusting the radiation control plate of the radiation control device so that the area of the heat receiving surface of the superheater is reduced when the temperature cannot be controlled to be constant. Control method of waste incinerator boiler as described in 4.   When the amount of heat generated by the waste is reduced, the flame size and brightness on the stoker is reduced, and the temperature of the superheated steam cannot be controlled with the temperature reducing device and the radiation control device alone, the primary air supply device can be used on the downstream side of the stoker. The primary air is increased and the position of the flame on the stoker is moved closer to the superheater to increase the amount of heat received by the superheater, and the amount of heat generated from the waste rises to increase the size of the flame on the stoker. When the brightness rises and the temperature of the superheated steam cannot be controlled at a constant level using only the temperature reducing device and radiation control device, the primary air near the upstream side of the stalker is increased by the primary air supply device, and the flame position on the stalker is overheated. The waste incinerator boiler control method according to claim 9 or 10, wherein the amount of heat received by the superheater is reduced by moving away from the vessel.

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