JP5995379B2 - Waste incinerator boiler control method - Google Patents

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. In connection with the improvement of the waste incinerator boiler control method in which the temperature is reduced and the temperature is adjusted and then further heated by the superheater arranged at the downstream position of the stalker to produce superheated steam, Even if the characteristics change and the flame on the stoker changes, the temperature of the superheated steam on the outlet side of the superheater can be controlled constantly at a constant level by controlling the supply amount of primary air, and the radiant heat from the flame can be effectively used. Can receive heat A method for controlling the waste incinerator boiler as.

  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 its purpose is to reduce the supply amount of primary air even if the supply amount and properties of waste fluctuate and the flame on the stoker changes. An object of the present invention is to provide a method for controlling a waste incinerator boiler that can control the temperature of superheated steam on the outlet side of the superheater to be always constant by controlling it, and can effectively receive radiant heat from a flame.

In order to achieve the above-mentioned object, the first invention of the present invention is to dry the waste on the stoker sequentially by dividing and supplying primary air by a primary air supply device under the stoker divided into a plurality of waste flow directions. Steam is generated by the boiler using the generated combustion exhaust gas, and the temperature of the steam is reduced by a temperature reducing device, the temperature is adjusted, and further superheated by a superheater disposed at a downstream position of the stalker. In order to keep the temperature of superheated steam on the outlet side of the superheater constant by reducing the temperature of the steam generated in the boiler with a temperature reducing device and adjusting the temperature. When the size and brightness 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 to a constant level using only the temperature reducing device, the primary air supply device Controls the distribution of primary air that is divided and supplied under the stoker according to the size and brightness of the flame, changes the position of the flame on the stoker to the downstream or upstream side of the stoker, and changes the amount of heat received by the superheater by flame radiation This is characterized in that the temperature of the superheated steam is kept constant.

According to a second aspect of the present invention, in the first aspect of the present 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, use the primary air supply device to increase the primary air on the downstream side of the stoker, move the flame position on the stoker closer to the superheater to increase the amount of heat received by the superheater, and generate heat from the waste. When the volume increases and the flame size and brightness increase on the stoker, and the temperature of the superheated steam cannot be controlled to a certain level with just the temperature reducing device, the primary air near the upstream side of the stoker is increased by the primary air supply device. It is characterized in that the amount of heat received by the superheater is reduced by moving the flame position on the stoker away from 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 primary air quantity dividedly supplied to the lower part of the stoker is controlled to change the position of the flame on the stoker so as to superheat the flame heater. The amount of waste heat received is changed so that the temperature of the superheated steam at the outlet side of the superheater must be constantly controlled even if the amount of waste supplied and the properties of the waste fluctuate and affect the flame on the stoker. Can do.

  In addition, according to the present invention, even when the amount of waste supplied and the properties greatly fluctuate to greatly change the size of the flame on the stoker and the temperature inside the furnace becomes an unexpected temperature, the position of the flame on the stoker Therefore, the superheater can effectively receive the radiant heat from the flame.

  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.

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 the like.

  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 by controlling the air volume controller 39 for 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. 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.

  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 temperature of the superheated steam S ′ is made constant only by the temperature reducing device 21. When the control cannot be performed, the primary air supply device 14 controls the distribution of the primary air A <b> 1 dividedly supplied below the stalker 5 according to the size and brightness of the flame on the stalker 5, and the flame position on the stalker 5 is positioned downstream of the stalker 5. The temperature of the superheated steam S ′ is kept constant by changing to the side or the upstream side and changing the amount of heat received by the superheater 20 by flame radiation. That is, in this waste incinerator boiler, the supply amount of the primary air A1, which has been determined for the purpose of achieving stable combustion, is varied to stabilize the properties of the superheated steam S '.

  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 adjustment is made to change the spray amount of the water C. As shown in the graph of FIG. (The range of c to d).

  By the way, the amount and property of waste B varies depending on the day and month, and when the size and brightness of the flame on the stoker 5 vary greatly, the spray range of the water C by the temperature reducing device 21 is within the range of the control width. In some cases, the water spray amount may not be within the range of 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 primary air supply device 14 is 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. By reducing the amount, the spray amount of the water C of 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.

  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.

  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 change the distribution of the primary air A1 from the pattern 1 shown in FIG. 3 to the pattern 2, and 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 ratio of the primary air A1 is 0.2, the drying stage 5a is 0.2, The front combustion stage 5b is changed to 0.2, the rear combustion stage 5c is set to 0.4, and the rear combustion stage 5d is changed to 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 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.

  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. 3 to the pattern 3, and 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 ratio of the primary air A1 is 0.2, the drying stage 5a is 0.3. The front combustion stage 5b is changed to 0.3, the rear combustion stage 5c is changed to 0.2, and the rear combustion stage 5d is changed 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 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.

  Thus, since the waste incinerator boiler combines the water spray control by the temperature reducing device 21 and the distribution control of the primary air A1 by the primary air supply device 14, the supply amount and properties of the waste B are large. Even when it fluctuates and affects the flame F on the stalker 5, the temperature of the superheated steam S 'on the outlet side of the superheater 20 can be controlled to be constant.

  Moreover, since the waste incinerator boiler can change the position of the flame F on the stalker 5 by controlling the amount of primary air A1 by controlling the distribution of the primary air A1 by the primary air supply device 14, the superheater 20 can be used as a flame. The radiant heat from can be effectively received.

  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 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 control valve, 45 temperature controller, 46 steam turbine, 47 generator, 48 condenser, A1 primary air, A2 secondary air, B waste, C water, S 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 (2)

The primary air is divided and supplied by the primary air supply device under the stoker divided in the direction of waste flow, the waste on the stoker is dried and burned sequentially, and steam is generated in the boiler by the generated combustion exhaust gas, A method for controlling a waste incinerator boiler in which the temperature of the steam is reduced by a temperature reducing device and the temperature is adjusted, and further superheated by a superheater disposed at a downstream position of the stalker to be superheated steam, The temperature of the superheated steam on the outlet side of the superheater is kept constant by reducing the temperature of the steam generated in the boiler with a temperature reducing device and adjusting the temperature. When the size and brightness of the heater changes and the temperature of the superheated steam cannot be controlled to a certain level with just the temperature reducing device, the primary air supply device divides and supplies the gas under the stoker according to the size and brightness of the flame on the stoker. The temperature of the superheated steam is kept constant by changing the position of the flame on the stoker to the downstream side or upstream side of the stoker and changing the amount of heat received by the superheater by flame radiation. A method for controlling a waste incinerator boiler, characterized by: When the amount of heat generated by the waste decreases and the size and brightness of the flame on the stalker decrease, and the temperature of the superheated steam cannot be controlled to a constant level using only the temperature reducing device, the primary air near the downstream side of the stalker is caused by the primary air supply device. To increase the amount of heat received by the superheater by moving the position of the flame on the stoker closer to the superheater, and the amount of heat generated from the waste increases, increasing the size and brightness of the flame on the stoker. When the temperature of the superheated steam cannot be controlled to a certain level using only the temperature reducing 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 moved away from the superheater. 2. The method for controlling a waste incinerator boiler according to claim 1, wherein the amount of heat received by the superheater is reduced.

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