JP2019007699A - Primary combustion gas supply control method, evaporation amount stabilization method, power generation amount stabilization method and fire grate type waste incinerator - Google Patents

Abstract

To provide a primary combustion gas supply control method for making a combustion state substantially constant to stabilize combustion.SOLUTION: A primary combustion gas supply control method comprises performing processing of, based on in-furnace detection that is at least one of a gas temperature in an incinerator, a gas temperature at an outlet of the incinerator, a discharged CO gas concentration in the incinerator, a discharged NOx gas concentration in the incinerator, a boiler evaporation amount with heat quantity recovery from exhaust gas, and a water-sprayed cooling water amount, for at least one configuration stage of fire grate, increasing or decreasing a supply amount of primary combustion gas supplied through a fire grate, and thus increasing or decreasing a supply amount of primary combustion gas supplied through an auxiliary supply passage.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control method for stabilizing combustion in a grate-type waste incinerator that incinerates while conveying waste by a grate.

  In a grate-type waste incinerator, it is important to stabilize the combustion in the furnace and stabilize the amount of generated heat in order to maintain stable waste combustion. Patent Documents 1 and 2 disclose techniques for stabilizing combustion in an incinerator.

The refuse incinerator of Patent Document 1 includes a combustion air supply meter, a cooling air supply meter, an O ₂ concentration meter, and combustion control means. The combustion control means acquires the amount of air supplied to the waste incinerator based on the measurement results of the combustion air supply meter and the cooling air supply meter. The combustion control means acquires the O ₂ concentration in the exhaust gas based on the measurement result of the O ₂ concentration meter. The combustion control means periodically calculates the amount of heat generated in the waste incinerator from these measured values, and controls the drying grate driving device to change the speed of the drying grate so that the generated heat amount is constant. At the same time, the amount of combustion air (primary combustion gas) supplied from below the grate is changed by controlling the combustion air damper.

  The waste incinerator of Patent Document 2 is based on the gas temperature of the gas mixing section where combustible gas (pyrolysis gas) generated in the drying process and combustion exhaust gas generated in the post-combustion process merge. The supply amount of primary combustion air (primary combustion gas) to be blown in more and the supply amount of secondary combustion air to be blown into the secondary combustion chamber are controlled.

JP-A-10-68514 JP 2002-147729 A

  However, in Patent Literature 1, only the supply amount of the primary combustion gas supplied from below the grate can be controlled as the supply amount control of the primary combustion gas. Therefore, for example, when the supply amount of the primary combustion gas supplied from below the grate is reduced, the generation of pyrolysis gas can be suppressed, but the primary combustion oxygen supplied into the furnace is reduced. Therefore, flame combustion is also suppressed at the same time. On the other hand, when the amount of primary combustion gas supplied from below the grate is increased, the generation of pyrolysis gas can be promoted, but the primary combustion oxygen supplied into the furnace also increases. Flame combustion is also facilitated at the same time. As described above, in the configuration of Patent Document 1, suppression / promotion of pyrolysis gas and suppression / promotion of flame combustion cannot be controlled independently, and combustion cannot be sufficiently stabilized. It was.

  Also in Patent Document 2, since the supply amount control of the primary combustion gas can only control the supply amount of the primary combustion gas blown from below the grate, there is a problem similar to that of Patent Document 1. Note that the secondary combustion gas contributes little or not to the primary combustion.

  The present invention has been made in view of the above circumstances, and its main object is to provide a primary combustion gas supply control method for stabilizing combustion by making the combustion state substantially constant. is there.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to the first aspect of the present invention, the following primary combustion gas supply control method is provided. That is, this primary combustion gas supply control method is performed for a grate-type waste incinerator including a transport unit, a wind box, an auxiliary supply path, and a boiler. The said conveyance part is comprised from the grate divided into the multistage, and conveys the said waste toward a furnace exit by operating intermittently in the state in which the waste was mounted. The wind boxes are respectively provided below the plurality of stages of the grate, and are supplied with a primary combustion gas to be supplied into the furnace via the grate. The auxiliary supply path supplies the primary combustion gas into the furnace without passing through the grate. The boiler recovers heat generated in the furnace. In this primary combustion gas supply control method, the gas temperature in the incinerator, the gas temperature at the incinerator outlet, the CO gas concentration in the incinerator, the NOx gas concentration in the incinerator, the amount of boiler evaporation accompanying the heat recovery from the exhaust gas, the water spray Based on the in-furnace detection data that is at least one of the cooling water amounts, the supply amount of the primary combustion gas supplied via the grate is reduced or increased for the grate of at least one component stage, and Along with this, a process of increasing or decreasing the supply amount of the primary combustion gas supplied through the auxiliary supply path is performed.

  According to the 2nd viewpoint of this invention, the grate-type waste incinerator of the following structures is provided. That is, the grate-type waste incinerator includes a transport unit, a wind box, an auxiliary supply path, a boiler, and a control device. The said conveyance part is comprised from the said grate divided into the multistage, and conveys the said waste toward a furnace exit by operating intermittently in the state in which the waste was mounted. The wind boxes are respectively provided below the plurality of stages of the grate, and are supplied with a primary combustion gas to be supplied into the furnace via the grate. The auxiliary supply path supplies the primary combustion gas into the furnace without passing through the grate. The boiler recovers heat generated in the furnace. The control device includes at least an incinerator gas temperature, an incinerator outlet gas temperature, an incinerator exhaust CO gas concentration, an incinerator exhaust NOx gas concentration, a boiler evaporation amount accompanying heat recovery from exhaust gas, and a water spray cooling water amount. Based on the in-furnace detection data, the supply amount of the primary combustion gas supplied through the grate is reduced or increased for the grate of at least one constituent stage, and the auxiliary A process of increasing or decreasing the supply amount of the primary combustion gas supplied through the supply path is performed.

  Thereby, the supply amount of the primary combustion gas supplied through the grate and the supply amount of the primary combustion gas supplied without going through the grate can be adjusted based on the in-furnace detection data. it can. The primary combustion gas supplied via the grate contributes to pyrolysis gasification and flame combustion. On the other hand, the primary combustion gas supplied without going through the grate mainly contributes to flame combustion. Therefore, an environment suitable for both pyrolysis gasification and flame combustion is realized by performing control to calculate and adjust the supply amount of the primary combustion gas supplied through the two paths as described above. it can. Therefore, combustion in the furnace can be stabilized.

  ADVANTAGE OF THE INVENTION According to this invention, the supply control method of the gas for primary combustion which can stabilize combustion by making combustion state substantially constant, and a grate-type waste incinerator can be provided.

The schematic block diagram of the waste incineration equipment containing the grate-type waste incinerator of one Embodiment of this invention. Functional block diagram of a grate-type waste incinerator. The conceptual diagram which shows the state on the grate in the prior art example 1. FIG. The conceptual diagram which shows the state on the grate in the prior art example 2. FIG. The conceptual diagram which shows the state on the grate in this embodiment.

  <Overall Configuration of Waste Incineration Facility> First, a waste incineration facility 100 including an incinerator 10 of this embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a waste incineration facility 100 including an incinerator 10 according to an embodiment of the present invention. In the following description, the terms “upstream” and “downstream” mean upstream and downstream in the direction in which waste, combustion gas, exhaust gas, primary air, secondary air, circulating exhaust gas, and the like flow.

  As shown in FIG. 1, the waste incineration facility 100 includes an incinerator 10, a boiler 30, and a steam turbine power generation facility 35. The incinerator 10 incinerates the supplied waste. The detailed configuration of the incinerator 10 will be described later.

  The boiler 30 generates steam using heat generated by combustion of waste. The boiler 30 generates steam (superheated steam) by exchanging heat between the high-temperature combustion gas generated in the furnace and water with a large number of water tubes 31 and superheater tubes 32 provided on the flow path wall. The steam generated by the water pipe 31 and the superheater pipe 32 is supplied to the steam turbine power generation facility 35.

  The steam turbine power generation facility 35 includes a turbine and a power generation device (not shown). The turbine is rotationally driven by steam supplied from the water pipe 31 and the superheater pipe 32. The power generation device generates power using the rotational driving force of the turbine.

  Here, in order to perform stable power generation, it is necessary to stabilize the generation amount of steam (superheated steam) in the boiler 30. In order to stabilize the amount of steam (superheated steam) generated in the boiler 30, it is necessary to stabilize the heat input to the boiler 30. That is, in order to keep the power generation amount constant, it is necessary to stabilize the amount of heat held by the combustion gas supplied from the incinerator 10 to the boiler 30 and to keep the heat input to the boiler 30 stable.

  <Configuration of Incinerator 10> The incinerator 10 includes a dust supply device 40 for supplying waste into the furnace. The dust feeder 40 includes a waste charging hopper 41 and a dust feeder main body 42. The waste input hopper 41 is a portion into which waste is input from outside the furnace. The dust feeder main body 42 is located at the bottom of the waste charging hopper 41 and is configured to be movable in the horizontal direction. The dust supply apparatus main body 42 supplies the waste thrown into the waste throwing hopper 41 to the downstream side. The movement speed, the number of movements per unit time, the movement amount (stroke), and the position of the stroke end (movement range) of the dust supply apparatus main body 42 are controlled by the control device 90 shown in FIG. The dust feeding device may be of a type that moves at a slight angle with respect to the horizontal direction.

  The waste supplied into the furnace by the dust supply device 40 is supplied by the transport unit 20 in the order of the drying unit 11, the combustion unit 12, and the post-combustion unit 13. The transport unit 20 includes a drying grate 21 provided in the drying unit 11, a combustion grate 22 provided in the combustion unit 12, and a post-combustion grate 23 provided in the post-combustion unit 13. Yes. Therefore, the conveyance part 20 is comprised from the multistage grate. Each grate is provided on the bottom surface of each part, on which waste is placed. The grate is composed of a movable grate and a fixed grate arranged side by side in the waste conveyance direction, and the movable grate intermittently advances and reverses to convey waste downstream. At the same time, the waste can be stirred. The operation of the grate is controlled by the control device 90. The grate is formed with a gap that allows gas to pass through.

  The drying unit 11 is a part for drying the waste supplied to the incinerator 10. The waste of the drying unit 11 is dried by the primary air supplied from below the drying grate 21 and the radiant heat of combustion in the adjacent combustion unit 12. At that time, pyrolysis gas is generated from the waste of the drying unit 11 by pyrolysis. Further, the waste of the drying unit 11 is conveyed toward the combustion unit 12 by the drying grate 21.

  The combustion unit 12 is a part that mainly burns the waste dried in the drying unit 11. In the combustion unit 12, the waste mainly causes flame combustion to generate a flame. Waste in the combustion unit 12, ash generated by combustion, and unburned unburned material are conveyed toward the rear combustion unit 13 by the combustion grate 22. Further, the combustion gas and flame generated in the combustion unit 12 pass through the throttle unit 17 and flow toward the rear combustion unit 13. The combustion grate 22 is provided at the same height as the dry grate 21, but may be provided at a position lower than the dry grate 21.

  The post-combustion unit 13 is a part for burning waste (unburned material) that could not be combusted in the combustion unit 12. In the post-combustion unit 13, combustion of unburned material that could not be combusted in the combustion unit 12 is promoted by the radiant heat of the combustion gas and the primary air. As a result, most of the unburned material becomes ash, and the unburned material decreases. The ash generated in the post-combustion unit 13 is conveyed toward the chute 24 by the post-combustion grate 23 provided on the bottom surface of the post-combustion unit 13. The ash conveyed to the chute 24 is discharged outside the waste incineration facility 100. The post-combustion grate 23 of this embodiment is provided at a position lower than the combustion grate 22, but may be provided at the same height as the combustion grate 22.

  As described above, since the reaction that occurs in the drying unit 11, the combustion unit 12, and the post-combustion unit 13 is different, each wall surface has a configuration that corresponds to the reaction that occurs. For example, since flame combustion occurs in the combustion unit 12, a structure having a higher fire resistance level than that of the drying unit 11 is employed.

  The recombustion part 14 is a part which burns the unburned gas contained in the combustion gas. The recombustion unit 14 extends upward from the drying unit 11, the combustion unit 12, and the post-combustion unit 13, and secondary air is supplied in the middle thereof. As a result, the combustion gas is mixed and agitated with the secondary air, and the unburned gas contained in the combustion gas is burned in the reburning section 14. Combustion that occurs in the combustion section 12 and the post-combustion section 13 is referred to as primary combustion, and combustion that occurs in the recombustion section 14 (that is, combustion of unburned gas remaining in the primary combustion) is referred to as secondary combustion.

  The gas supply device 50 is a device that supplies gas into the furnace. The gas supply device 50 according to this embodiment includes a primary air supply unit 51, a secondary air supply unit 52, and an exhaust gas supply unit 53. Each supply part is comprised by the air blower for attracting | sucking or sending out gas.

  In this specification, the gas supplied for primary combustion is called primary combustion gas. The primary combustion gas includes primary air, circulating exhaust gas, and mixed gas thereof. The primary air is air taken from outside and is not used for combustion or the like (that is, excluding circulating exhaust gas). Therefore, the primary air includes a gas obtained by heating air taken from the outside. Similarly, in this specification, the gas supplied for secondary combustion is called secondary combustion gas. Secondary combustion gas includes secondary air, circulating exhaust gas, and mixed gas thereof. The definition of secondary air is the same as primary air.

  The primary air supply unit 51 supplies primary air into the furnace via the primary air supply path 71. The primary air supply path 71 is branched into a first supply path 71a, a second supply path 71b, a third supply path 71c, and an auxiliary supply path 71d. A heater may be provided in the primary air supply path 71 so that the temperature of the primary air supplied to each part can be adjusted.

  The first supply path 71 a is a path for supplying primary air to the drying stage wind box 25 provided below the drying grate 21. A first damper 81 is provided in the first supply path 71a, and the supply amount of primary air supplied to the dry-stage wind box 25 can be adjusted. The first damper 81 is controlled by the control device 90.

  The second supply path 71 b is a path for supplying primary air to the combustion stage wind box 26 provided below the combustion grate 22. A second damper 82 is provided in the second supply path 71b, and the supply amount of primary air supplied to the combustion stage wind box 26 can be adjusted. The second damper 82 is controlled by the control device 90.

  The third supply path 71 c is a path for supplying primary air to the post-combustion stage wind box 27 provided below the post-combustion grate 23. A third damper 83 is provided in the third supply path 71c, and the supply amount of primary air supplied to the post-combustion stage wind box 27 can be adjusted. The third damper 83 is controlled by the control device 90.

  The auxiliary supply path 71 d is a path for supplying primary air to the combustion unit 12 without passing through the combustion grate 22. As a matter of course, the auxiliary supply path 71d does not pass through the combustion stage wind box 26, but other grate and wind box (dry grate 21, post combustion grate 23, dry stage wind box 25, and rear The combustion wind box 27) is not routed either. A fourth damper 84 is provided in the auxiliary supply path 71d, and the supply amount of primary air supplied by the auxiliary supply path 71d can be adjusted. The fourth damper 84 is controlled by the control device 90. The fourth damper 84 is controlled to supplement the primary air supplied by the second supply path 71b with the primary air supplied by the auxiliary supply path 71d. For example, when the second damper 82 is controlled so as to decrease (increase) the supply amount of primary air supplied by the second supply passage 71b, the supply amount of primary air supplied by the auxiliary supply passage 71d increases. Thus, the fourth damper 84 is controlled. The auxiliary supply path 71d is a path for supplying primary air to the combustion unit 12 from, for example, both side surfaces (the front side and the back side) of the furnace. In the present embodiment, the auxiliary supply path 71d supplies the primary air downstream from the combustion grate 22, but may be configured to supply primary air upstream from the combustion grate 22, or in the transport direction. The primary air may be supplied to a portion overlapping the combustion grate 22 (for example, a side wall of a portion where the combustion grate 22 is located). Thus, the route of the auxiliary supply route 71d is not particularly limited, but it is necessary to supply air so as to contribute to the primary combustion in the combustion unit 12 (that is, toward the vicinity of the flame so as to aim at the flame). is there.

  In the present embodiment, the auxiliary supply path 71d is configured to supplement the primary air (primary combustion gas) supplied to the combustion unit 12, but in addition to or instead of this, the auxiliary supply path 71d is supplied to the drying unit 11. An auxiliary supply path that supplements primary air (primary combustion gas) may be formed, or an auxiliary supply path that supplements primary air (primary combustion gas) supplied to the post-combustion unit 13 may be formed. .

  The secondary air supply unit 52 supplies secondary air from the upper part (ceiling part) to the air gas holding space 16 of the incinerator 10 through the secondary air supply path 72, and combustion gas is generated by the throttle unit 17. Secondary air is supplied to the direction changing portion (near the throttle portion 17). The secondary air supply unit 52 is provided with a damper (not shown) controlled by the control device 90, and can adjust the supply amount of secondary air to each unit.

  The exhaust gas supply unit 53 supplies (recirculates) the exhaust gas discharged from the waste incineration facility 100 into the furnace via the circulating exhaust gas supply path 73. The exhaust gas discharged from the waste incineration facility 100 is purified by a filtration type dust collector 60, and a part of the exhaust gas is incinerated from both side surfaces (the front side and the back side of the page) of the combustion unit 12 by the exhaust gas supply unit 53. Supplied to the furnace 10. The position where the exhaust gas is supplied is not particularly limited. For example, the exhaust gas may be supplied from the upper side (ceiling part) of the incinerator 10, or may be supplied only from one side surface. By supplying the exhaust gas to the incinerator 10, the oxygen concentration in the incinerator 10 is reduced, and a local excessive increase in the combustion temperature can be suppressed. As a result, generation of NOx can be suppressed.

  As shown in FIGS. 1 and 2, the incinerator 10 is provided with a plurality of sensors for grasping the combustion state and the like. Specifically, an incinerator gas temperature sensor 91, an incinerator outlet gas temperature sensor 92, a CO gas concentration sensor 93, and a NOx gas concentration sensor 94 are provided.

  The incinerator gas temperature sensor 91 is disposed in the incinerator 10 (for example, downstream of the air gas holding space 16 and upstream of the post-combustion unit 13), and detects the gas temperature in the incinerator and controls the controller 90. Output to. The incinerator outlet gas temperature sensor 92 is disposed in the vicinity of the outlet of the incinerator 10 (for example, downstream of the recombustion unit 14 and upstream of the boiler 30), and detects the temperature of the incinerator outlet gas and outputs it to the control device 90. To do. The CO gas concentration sensor 93 is disposed downstream of the dust collector 60, detects the CO gas concentration contained in the exhaust gas (incinerator exhaust CO gas concentration), and outputs it to the control device 90. The NOx gas concentration sensor 94 is disposed downstream of the dust collector 60, detects the NOx gas concentration (incinerator exhaust NOx gas concentration) contained in the exhaust gas, and outputs it to the control device 90.

  The control device 90 includes a CPU, a RAM, a ROM, and the like, performs various calculations, and controls the entire waste incineration facility 100. Hereinafter, among the controls performed by the control device 90, automatic combustion control and primary combustion gas ratio adjustment control will be described.

  <Automatic Combustion Control> Data relating to combustion in the incinerator 10 (in-furnace detection data) is supplied to the control device 90 from the plurality of sensors described above. Further, the boiler 30 outputs the amount of boiler evaporation (the amount of steam generated in the boiler 30 in accordance with the recovery of heat and the amount of steam supplied to the steam turbine power generation facility 35) to the control device 90.

  From the incinerator gas temperature detected by the incinerator gas temperature sensor 91 and the incinerator outlet gas temperature detected by the incinerator outlet gas temperature sensor 92, the extent of combustion occurring in the furnace can be estimated. Yes (combustion is more active at higher temperatures). Further, from the incinerator exhaust CO gas concentration detected by the CO gas concentration sensor 93, the concentration of unburned gas that could not be burned in the furnace (how much unburned gas is generated) can be grasped. From the incinerator exhaust NOx gas concentration detected by the NOx gas concentration sensor 94, the concentration of NOx gas generated in the furnace (and thus the difference from the target NOx gas concentration) can be grasped. In addition, the amount of heat generated in the furnace can be estimated from the amount of boiler evaporation. In addition, in an incinerator configured to cool by water spray in addition to a waste heat recovery boiler, more accurately estimate the amount of heat generated in the furnace based on the amount of water spray cooling water in addition to the amount of boiler evaporation. can do.

  The automatic combustion control is a control for comprehensively judging the above-mentioned detection data in the furnace and stably maintaining the combustion state in the furnace for a long period of time. Specifically, as shown in FIG. 2, the control device 90 adjusts the supply amount of gas supplied to each part by adjusting the first damper 81 to the third damper 83. Although not shown in FIG. 2, the controller 90 also adjusts dampers (not shown) provided in the secondary air supply path 72 and the circulating exhaust gas supply path 73. Further, the control device 90 adjusts the operations of the dry grate 21, the combustion grate 22, and the post-combustion grate 23. The operation of each grate includes, for example, a speed when moving forward, a standby time until starting backward after moving forward, a speed when moving backward, a time interval between a series of actions, and the like. Further, in this specification, for the sake of simplicity of explanation, “control the grate” is described, but actually, the control device 90 controls the drive unit of each grate. As described above, by controlling the various devices described above based on various in-furnace detection data, the combustion state in the furnace can be stably maintained over a long period of time. The combustion that occurs in the incinerator 10 varies greatly depending on the shape and structure of the incinerator 10 and the waste that is input. Moreover, the target value in the automatic combustion control also varies greatly depending on the durability of the incinerator 10, the required processing amount, the legal regulations on exhaust gas, and the like. Therefore, the control device 90 judges them comprehensively and performs automatic combustion control.

  <Primary Combustion Gas Ratio Adjustment Control> Primary combustion gas ratio adjustment control refers to the supply amount of the primary combustion gas supplied via the grate and the primary combustion gas supplied without going through the grate. It is control which adjusts the ratio of supply amount. In the present embodiment, the supply amount of primary air supplied to the combustion unit 12 via the combustion grate 22 (via the second supply path 71b) by adjusting the second damper 82 and the fourth damper 84. And the supply amount of primary air supplied to the combustion unit 12 without going through the combustion grate 22 (via the auxiliary supply path 71d). By performing the primary combustion gas ratio adjustment control, it is possible to make the combustion state substantially constant in accordance with the change in the combustion state generated in the incinerator 10, thereby stabilizing the combustion.

  First, it will be described with reference to FIGS. 3 and 4 that the combustion state fluctuates by the conventional method and combustion cannot be stabilized. FIG. 3 is a conceptual diagram showing a state on the grate in the first conventional example. FIG. 4 is a conceptual diagram showing a state on the grate in the second conventional example.

  The primary combustion gas supplied from under the grate (via the grate) passes through the gap in the waste layer above the grate after passing through the grate. As the primary combustion gas passes through the waste, the waste around the gap that has passed through is heated and contacted with oxygen in the air. As a result, the waste in contact with the primary combustion gas is partially pyrolyzed and gasified, and the pyrolysis gas containing a high concentration of unburned gas components such as hydrocarbons and carbon monoxide from the surface of the waste. It is discharged upward. The pyrolysis gas contains unreacted components in the air. Thereafter, this pyrolysis gas undergoes a violent oxidation reaction by diffusion mixing of oxygen molecules from the primary combustion gas containing oxygen in the furnace, and flame combustion occurs.

  In the incinerator 10, the combustion state changes due to changes in the properties of the input waste, the operation of the grate, changes in the gas supply amount, and the like. For example, when waste that easily generates pyrolysis gas is introduced, flame combustion tends to be active under conditions such as sufficient oxygen. In addition, during the operation of the grate, contact between the primary combustion gas and the waste is promoted, so that pyrolysis gas is likely to be generated, and flame combustion is active under conditions such as sufficient oxygen is present. Easy to be. Below, the case where excessive flame combustion (excess combustion) generate | occur | produces by the change of these conditions is considered.

  When no special measures are taken against the occurrence of excessive combustion, it is natural that excessive combustion occurs as shown in FIG. When excessive combustion occurs, the amount of heat generated in the furnace becomes non-uniform. As a result, the amount of evaporation of the boiler 30 connected to the incinerator 10 becomes non-uniform, and the amount of power generated by the steam turbine power generation facility 35 connected to the boiler 30 also becomes non-uniform. In addition, due to the occurrence of excessive combustion, there is a possibility that the wall portion or the like will be thermally damaged.

  Next, as shown in FIG. 4, a case is considered in which the occurrence of excessive combustion is detected or predicted, and control is performed to reduce the supply amount of the primary combustion gas supplied through the grate. By reducing the primary combustion gas supplied from below the grate, the contact between the primary combustion gas and the waste is reduced, so that the generated pyrolysis gas can be suppressed to the same level as before the occurrence of excessive combustion. However, because the amount of primary combustion gas supplied from below the grate has only been reduced, the flame combustion part where pyrolysis gas is formed to the same extent as before the occurrence of excessive combustion causes oxygen shortage and flame combustion. Will be reduced accordingly. Such a low level of flame combustion is referred to as undercombustion (a state opposite to overcombustion). That is, excessive combustion can be suppressed only by reducing the supply amount of the primary combustion gas supplied from below the grate, but insufficient combustion may occur.

  Considering the above, in the present embodiment, the following control is performed as shown in FIG. That is, the controller 90 detects the above-mentioned in-furnace detection data (specifically, incinerator gas temperature, incinerator outlet gas temperature, incinerator exhaust CO gas concentration, incinerator exhaust NOx gas concentration, boiler evaporation amount, and The occurrence of excessive combustion is detected or predicted based on at least one of the water spray cooling water amounts). As described above, since the combustion state occurring in the furnace can be estimated by using the above-mentioned detection data in the furnace, the degree of combustion can be estimated. For example, when the degree of combustion is high, it is detected that excessive combustion has occurred, and when the degree of combustion is not so high but gradually increases, it is predicted that excessive combustion will occur in the future. When the occurrence of excessive combustion is detected or predicted, the control device 90 reduces the supply amount of the primary combustion gas supplied through the grate and also through the auxiliary supply path 71d (without using the grate The first supply amount adjustment control for increasing the supply amount of the primary combustion gas to be supplied is performed. Describing the first supply amount adjustment control conceptually, the reduced primary combustion gas that should have been supplied via the grate is supplied onto the grate without going through the grate. . As described with reference to FIG. 4, by reducing the primary combustion gas supplied through the grate, generation of pyrolysis gas can be suppressed to the same extent as before the occurrence of excessive combustion. In the present embodiment, since the reduced primary combustion gas is supplied from the grate, the flame does not cause oxygen shortage in the flame formation portion of the pyrolysis gas, which is the same level as before the occurrence of excessive combustion. Since the degree of combustion can be maintained, the combustion state can be maintained, and combustion can be stabilized.

  Thus, in the first supply amount adjustment control, the supply amount of the primary combustion gas supplied via the grate, the supply amount of the primary combustion gas supplied via the auxiliary supply path 71d, and the supply amount thereof The change timing is determined based on the in-furnace detection data described above. That is, since the degree of combustion is different even if it is excessive combustion, for example, when the degree of combustion is high even in excessive combustion, there is a possibility that the supply amount of the primary combustion gas supplied through the auxiliary supply path 71d may increase. There is.

  In the present embodiment, it is assumed that the supply amount of the primary combustion gas supplied through the auxiliary supply path 71d is zero during normal combustion, but this supply amount may not be zero. . Further, the amount of decrease (increase amount) of the primary combustion gas supplied via the grate and the amount of increase (decrease amount) of the primary combustion gas supplied via the auxiliary supply path 71d are approximated to some extent ( Or the same), but they may be different. If one decrease amount and the other increase amount are approximated or the same, the specific supply amount can be determined by determining the ratio of supply through the grate. Also, the change timing of the supply amount of the primary combustion gas supplied via the grate and the change timing of the supply amount of the primary combustion gas supplied via the auxiliary supply path 71d are approximated to some extent (or Preferably match) but may be different.

  After that, the control device 90 detects the degree of combustion based on the in-furnace detection data, and when determining that the occurrence of excessive combustion is suppressed, the supply amount of the primary combustion gas supplied through the grate And a second supply amount adjustment control for reducing the supply amount of the primary combustion gas supplied through the auxiliary supply path 71d. As described above, the primary combustion gas ratio adjustment control performs the first supply amount adjustment control and the second supply amount adjustment control based on the in-furnace detection data, thereby generating the pyrolysis gas generation amount and the combustion. Since the degree of flame can be made the same, combustion can be stabilized.

  In addition, although it is possible to independently control the primary combustion gas ratio adjustment control and the automatic combustion control, in the present embodiment, these controls are performed in cooperation and combination. Specifically, the automatic combustion control manages and controls the primary combustion gas ratio adjustment control, thereby integrating the primary combustion gas ratio adjustment control into the automatic combustion control. Therefore, the value calculated independently by the primary combustion gas ratio adjustment control is not used, but the above-mentioned in-furnace detection data used on the automatic combustion control side and the control data calculated by the automatic combustion control (the state of each damper) And the supply amount to be changed by the first supply amount adjustment control and the second supply amount adjustment control are adjusted based on, for example, data for instructing the grate speed. Therefore, depending on the combustion state in the furnace, the amount of decrease (increase amount) of the primary combustion gas supplied via the grate and the amount of increase (decrease amount) of the primary combustion gas supplied without going through the grate ) Will increase or decrease.

  As described above, the primary combustion gas supply control method according to the present embodiment includes the transport unit 20, the wind box (from the dry stage wind box 25 to the post-combustion stage wind box 27), the auxiliary supply path 71d, It is performed with respect to the incinerator 10 provided with. The conveyance part 20 is comprised from the grate divided into the multistage, and conveys the said waste toward a furnace exit by operating intermittently in the state in which the waste was mounted. The wind boxes are respectively provided below the plurality of stages of grate, and are supplied with primary combustion gas to be supplied into the furnace via the grate. The auxiliary supply path 71d supplies the primary combustion gas into the furnace without passing through the grate. In this primary combustion gas supply control method, the gas temperature in the incinerator, the gas temperature at the incinerator outlet, the CO gas concentration in the incinerator, the NOx gas concentration in the incinerator, the amount of boiler evaporation accompanying the heat recovery from the exhaust gas, the water spray Based on the in-furnace detection data that is at least one of the cooling water quantities, the supply quantity of the primary combustion gas supplied via the grate is reduced or increased for the grate of at least one component stage, and accompanying this Thus, a process of increasing or decreasing the supply amount of the primary combustion gas supplied through the auxiliary supply path is performed.

  Thereby, the supply amount of the primary combustion gas supplied through the grate and the supply amount of the primary combustion gas supplied without going through the grate can be adjusted based on the in-furnace detection data. it can. The primary combustion gas supplied via the grate contributes to pyrolysis gasification and flame combustion. On the other hand, the primary combustion gas supplied without going through the grate mainly contributes to flame combustion. Therefore, an environment suitable for both pyrolysis gasification and flame combustion is realized by performing control to calculate and adjust the supply amount of the primary combustion gas supplied through the two paths as described above. it can. Therefore, the combustion of the incinerator 10 can be stabilized.

  By stabilizing the combustion of the incinerator 10, the evaporation amount of the boiler 30 connected to the incinerator 10 can be stabilized. Furthermore, by stabilizing the evaporation amount of the boiler 30, the power generation amount of the steam turbine power generation facility 35 connected to the boiler 30 can be stabilized.

  The preferred embodiment of the present invention has been described above, but the above configuration can be modified as follows, for example.

  In the above embodiment, automatic combustion control and primary combustion gas supply control are performed based on the incinerator gas temperature, incinerator outlet gas temperature, incinerator exhaust CO gas concentration, incinerator exhaust NOx gas concentration, and boiler evaporation amount. Although it is the structure to perform, you may perform these controls using some (at least 1) of these in-furnace detection data. Further, these controls may be performed using the water spray cooling water amount instead of the boiler evaporation amount.

  In the above embodiment, the second supply path 71b and the auxiliary supply path 71d are branched from the same path (supplied by the same primary air supply unit 51). Instead, the second supply path 71b and the auxiliary supply path 71d may be connected to different paths (supplied by different primary air supply units).

  In the above embodiment, the transport unit 20 is configured by a three-stage grate having a dry grate 21, a combustion grate 22, and a post-combustion grate 23. It may replace with this and the conveyance part 20 may be comprised with the grate | blade other than a three-stage | paragraph. For example, the dry grate 21 may be omitted, and the transport unit 20 may be configured with a combustion grate 22 and a post-combustion grate 23.

10 Incinerator (grate-type waste incinerator)
DESCRIPTION OF SYMBOLS 11 Drying part 12 Combustion part 13 Post combustion part 21 Dry grate 22 Combustion grate 23 Post combustion grate 25 Dry stage wind box 26 Combustion stage wind box 27 Post combustion stage wind box 71 Primary air supply path 71a 1st supply path 71b Second supply path 71c Third supply path 71d Auxiliary supply path 90 Controller

Claims (4)

It is composed of a grate divided into a plurality of stages, and a transport unit that transports the waste toward the furnace outlet by intermittently operating in a state where the waste is placed;
A wind box that is provided below each of the plurality of stages of the grate and is supplied with a primary combustion gas to be supplied into the furnace via the grate,
An auxiliary supply path for supplying the primary combustion gas into the furnace without going through the grate,
And a method for controlling the primary combustion gas for a grate-type waste incinerator connected to a boiler that recovers heat generated in the furnace,
Incinerator gas temperature, incinerator outlet gas temperature, incinerator exhaust CO gas concentration, incinerator exhaust NOx gas concentration, boiler evaporation accompanying heat recovery from exhaust gas, water spray cooling water amount On the basis of the internal detection data, the supply amount of the primary combustion gas supplied through the grate is reduced or increased for the grate in at least one constituent stage, and accordingly, through the auxiliary supply path. A supply control method for a primary combustion gas, characterized in that a process for increasing or decreasing the supply amount of the primary combustion gas to be supplied is performed.   The amount of evaporation of the boiler connected to the grate waste incinerator is stabilized by controlling the grate waste incinerator using the primary combustion gas supply control method according to claim 1. Evaporation amount stabilization method.   A power generation amount stabilization method for stabilizing the power generation amount of a steam turbine power generation facility connected to the boiler by stabilizing the evaporation amount of the boiler using the evaporation amount stabilization method according to claim 2. In a grate-type waste incinerator that incinerates while transporting waste through a grate,
Consists of the grate divided into a plurality of stages, a transport unit that transports the waste toward the furnace outlet by intermittently operating in a state where the waste is placed,
A wind box that is provided below each of the plurality of stages of the grate and is supplied with a primary combustion gas to be supplied into the furnace via the grate,
An auxiliary supply path for supplying the primary combustion gas into the furnace without going through the grate,
A control device;
And connected to a boiler that recovers the heat generated in the furnace,
The control device includes at least an incinerator gas temperature, an incinerator outlet gas temperature, an incinerator exhaust CO gas concentration, an incinerator exhaust NOx gas concentration, a boiler evaporation amount accompanying heat recovery from exhaust gas, and a water spray cooling water amount. Based on the in-furnace detection data, the supply amount of the primary combustion gas supplied through the grate is reduced or increased for the grate of at least one constituent stage, and the auxiliary A grate-type waste incinerator characterized by performing a process of increasing or decreasing the amount of primary combustion gas supplied through a supply path.

Images