JP6797082B2 - Primary combustion gas supply control method, evaporation amount stabilization method, power generation amount stabilization method, and grate-type waste incinerator - Google Patents

Description

The present invention relates to a control method for stabilizing the combustion of a grate-type waste incinerator that incinerates waste while transporting it by a grate.

In a grate-type waste incinerator, it is important to stabilize the combustion in the furnace to stabilize the amount of heat generated in order to maintain stable waste combustion. In this regard, the waste incinerator of Patent Document 1 is provided with a damper for adjusting the supply amount of air supplied to the stoker section (grate), and the air supplied by squeezing the damper at the start of operation of the stoker section. A control method for reducing the amount (supply amount of primary combustion gas) is disclosed. Since rapid combustion is likely to occur when the stoker is operated, rapid combustion can be suppressed by reducing the amount of air supplied.

Japanese Unexamined Patent Publication No. 7-19445

However, in Patent Document 1, since the amount of air supplied from under the grate is only reduced, oxygen deficiency is caused in the flame combustion portion where the pyrolysis gas reacts, and the degree of flame combustion is reduced by that amount. As a result, when the grate is operating, the combustion state in the state where the grate is stationary cannot be maintained, and the combustion state cannot be stabilized.

The present invention has been made in view of the above circumstances, and its main purpose is primary combustion capable of stabilizing combustion by making the combustion state substantially constant regardless of the presence or absence of operation of the grate. The purpose is to provide a method for controlling the supply of gas.

The problem to be solved by the present invention is as described above, and next, the means for solving this problem and its effect will be described.

According to the first aspect of the present invention, the following method for controlling the supply of the primary combustion gas is provided. That is, this method of controlling the supply of the primary combustion gas is performed on a grate-type waste incinerator including a transport unit, a wind box, and an auxiliary supply path. The transport unit is composed of a grate divided into a plurality of stages, and transports the waste toward the furnace outlet by operating intermittently with the waste loaded. The air box is provided below each of the plurality of stages of the grate, and the primary combustion gas for supplying into the furnace is supplied via the grate. The auxiliary supply path, without passing through the grate, and supplies the primary combustion gas to the inside of the flame rather than outside of the flame is on the grate of the furnace. In this method of controlling the supply of the primary combustion gas, the supply amount of the primary combustion gas supplied through the grate is reduced or increased in accordance with the operation of the grate for the grate of at least one constituent stage. At the same time, control is performed to increase or decrease the supply amount of the primary combustion gas supplied through the auxiliary supply path.

According to the second aspect of the present invention, a grate type waste incinerator having the following configuration is provided. That is, this grate-type waste incinerator includes a transport unit, a wind box, an auxiliary supply path, and a control device. The transport unit is composed of the grate divided into a plurality of stages, and transports the waste toward the furnace outlet by operating intermittently with the waste loaded. The air box is provided below each of the plurality of stages of the grate, and the primary combustion gas for supplying into the furnace is supplied via the grate. The auxiliary supply path, without passing through the grate, and supplies the primary combustion gas to the inside of the flame rather than outside of the flame is on the grate of the furnace. The control device reduces or increases the supply amount of the primary combustion gas supplied through the grate for the grate of at least one constituent stage according to the operation of the grate, and the auxiliary supply path. Control is performed to increase or decrease the supply amount of the primary combustion gas supplied through.

As a result, for example, the amount of pyrolysis gas generated is about the same as when the grate is not operating by reducing the amount of primary combustion gas supplied via the grate in response to the start of operation of the grate. At the same time, by increasing the supply amount of the primary combustion gas supplied without passing through the grate, the oxygen required for the flame combustion reaction (reaction of the pyrolysis gas) is supplied, so that the oxygen shortage can be prevented. Therefore, even during the operation of the grate, combustion is performed to the same extent as when it is not operating, so that the combustion can be stabilized.

According to the present invention, it is possible to provide a method for controlling the supply of a primary combustion gas capable of stabilizing combustion by keeping the combustion state substantially constant regardless of the presence or absence of operation of the grate.

The schematic block diagram of the waste incineration facility including the incinerator of one Embodiment of this invention. Functional block diagram of the incinerator. The conceptual diagram which shows the state on the grate before and after the grate operation in the prior art example 1. FIG. The conceptual diagram which shows the state on the grate before and after the grate operation in the prior art example 2. FIG. The conceptual diagram which shows the state on the grate before and after the grate operation in this embodiment. Timing chart regarding the supply of gas for primary combustion.

<Overall Configuration of Waste Incineration Facility> First, the waste incineration facility 100 including the incinerator 10 of the present embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a waste incinerator 100 including an incinerator 10 according to an embodiment of the present invention. In the following description, when the terms "upstream" and "downstream" are simply used, they mean upstream and downstream in the direction in which waste, combustion gas, exhaust gas, primary air, secondary air, circulating exhaust gas, etc. 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 uses the heat generated by the combustion of waste to generate steam. The boiler 30 generates steam (superheated steam) by exchanging heat between high-temperature combustion gas generated in the furnace and water in a large number of water pipes 31 and superheater pipes 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 uses the rotational driving force of the turbine to generate electricity.

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

<Structure of Incinerator 10> The incinerator 10 includes a dust supply device 40 for supplying waste into the furnace. The dust supply device 40 includes a waste input hopper 41 and a dust supply device main body 42. The waste input hopper 41 is a portion where waste is input from outside the furnace. The dust supply device main body 42 is located at the bottom of the waste input hopper 41 and is configured to be movable in the horizontal direction. The dust supply device main body 42 supplies the waste charged into the waste input hopper 41 to the downstream side. The movement speed of the dust supply device main body 42, the number of movements per unit time, the movement amount (stroke), and the position of the stroke end (movement range) are controlled by the control device 90 shown in FIG. The dust supply 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 is composed of a dry 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. There is. Therefore, the transport unit 20 is composed of a plurality of stages of grate. Each grate is provided on the bottom surface of each part, and waste is placed on it. The grate is composed of a movable grate and a fixed grate arranged side by side in the waste transport direction, and the movable grate intermittently moves forward and backward to transport waste to the downstream side. At the same time, the waste can be agitated. The operation of the grate is controlled by the control device 90. In addition, a gap having a size that allows gas to pass through is formed in the grate.

The drying unit 11 is a portion for drying the waste supplied to the incinerator 10. The waste of the drying unit 11 is dried by the primary air supplied from under the drying grate 21 and the radiant heat of combustion in the adjacent combustion unit 12. At that time, thermal decomposition gas is generated from the waste of the drying portion 11 by thermal decomposition. 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 portion that mainly burns the waste dried by the drying unit 11. In the combustion unit 12, the waste mainly causes flame combustion to generate a flame. The waste in the combustion unit 12, the ash generated by combustion, and the unburned material that cannot be completely burned are conveyed toward the post-combustion unit 13 by the combustion grate 22. Further, the combustion gas and the flame generated in the combustion unit 12 pass through the throttle unit 17 and flow toward the post-combustion unit 13. Although the combustion grate 22 is provided at the same height as the dry grate 21, it may be provided at a position lower than that of the dry grate 21.

The post-combustion section 13 is a section that burns waste (unburned matter) that could not be completely burned by the combustion section 12. In the post-combustion unit 13, the radiant heat of the combustion gas and the primary air promote the combustion of the unburned material that could not be completely burned in the combustion unit 12. 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 to the outside of the waste incineration facility 100. Although the post-combustion grate 23 of the present embodiment is provided at a position lower than the combustion grate 22, it may be provided at the same height as the combustion grate 22.

As described above, since the reactions that occur in the drying unit 11, the combustion unit 12, and the post-combustion unit 13 are different, the wall surface and the like are configured according to the reaction that occurs. For example, since flame combustion occurs in the combustion unit 12, a structure having a higher refractory level than the drying unit 11 is adopted.

The reburning unit 14 is a part that burns the unburned gas contained in the combustion gas. The re-combustion 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 unit 14. The combustion generated in the combustion unit 12 and the post-combustion unit 13 is referred to as primary combustion, and the combustion generated in the recombustion unit 14 (that is, the combustion of the 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 of the present embodiment includes a primary air supply unit 51, a secondary air supply unit 52, and an exhaust gas supply unit 53. Each supply unit is composed of a blower for attracting or sending out gas.

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

The primary air supply unit 51 supplies the 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 71a is a path for supplying primary air to the drying step air box 25 provided below the drying grate 21. A first damper 81 is provided in the first supply path 71a, and the amount of primary air supplied to the drying stage air box 25 can be adjusted. Further, the first damper 81 is controlled by the control device 90.

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

The third supply path 71c is a path for supplying primary air to the post-combustion stage air 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 the primary air supplied to the post-combustion stage air box 27 can be adjusted. Further, the third damper 83 is controlled by the control device 90.

The auxiliary supply path 71d is a path for supplying the 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 air box 26, but other grate and air box (dry grate 21, post-combustion grate 23, dry stage air box 25, and rear). It does not pass through the combustion stage wind box 27). A fourth damper 84 is provided in the auxiliary supply path 71d, and the supply amount of the primary air supplied by the auxiliary supply path 71d can be adjusted. Further, the fourth damper 84 is controlled by the control device 90. The fourth damper 84 is controlled so as 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 that the supply amount of the primary air supplied by the second supply path 71b decreases (increases), the supply amount of the primary air supplied by the auxiliary supply path 71d increases. The fourth damper 84 is controlled so as to (decrease). The auxiliary supply path 71d is a path for supplying primary air to the combustion unit 12 from, for example, both side surfaces (front side and back side of the paper surface) in the furnace. In the present embodiment, the auxiliary supply path 71d supplies the primary air to the downstream side of the combustion grate 22, but it may be configured to supply the primary air to the upstream side of 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, the side wall of the portion where the combustion grate 22 is located). As described above, the path of the auxiliary supply path 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 is supplied to the drying unit 11 in addition to or instead of this. An auxiliary supply path for supplementing the primary air (primary combustion gas) may be formed, or an auxiliary supply path for supplementing the primary air (primary combustion gas) supplied to the post-combustion unit 13 may be formed. ..

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

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 the filtration type dust collector 60, and a part of the exhaust gas is incinerated by the exhaust gas supply unit 53 from both side surfaces (front side and back side of the paper surface) of the combustion unit 12. It is 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 above (ceiling portion) of the incinerator 10, or may be supplied from only one side surface. By supplying the exhaust gas to the incinerator 10, the oxygen concentration in the incinerator 10 is lowered, and the local excessive rise in the combustion temperature can be suppressed. As a result, the 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 gas temperature sensor 91 in the incinerator is arranged in the incinerator 10 (for example, downstream of the air gas holding space 16 and upstream of the post-combustion unit 13), detects the gas temperature in the incinerator, and controls the control device 90. Output to. The incinerator outlet gas temperature sensor 92 is arranged near the incinerator 10 outlet (for example, downstream of the reburning unit 14 and upstream of the boiler 30), detects the incinerator outlet gas temperature, and outputs the temperature to the control device 90. To do. The CO gas concentration sensor 93 is arranged downstream of the dust collector 60, detects the CO gas concentration contained in the exhaust gas (CO gas concentration discharged from the incinerator), and outputs the CO gas concentration sensor 93 to the control device 90. The NOx gas concentration sensor 94 is arranged downstream of the dust collector 60, detects the NOx gas concentration contained in the exhaust gas (NOx gas concentration discharged from the incinerator), and outputs the NOx gas concentration sensor 94 to the control device 90.

The control device 90 is composed of a CPU, RAM, ROM, etc., 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 related to combustion of the incinerator 10 (in-core 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 by the boiler 30 as a result of heat recovery, the amount of steam supplied to the steam turbine power generation facility 35) to the control device 90.

The degree of combustion occurring in the incinerator can be estimated 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. Yes (the higher the temperature, the more active the combustion). Further, from the CO gas concentration discharged from the incinerator detected by the CO gas concentration sensor 93, the concentration of the unburned gas that could not be completely burned in the furnace (how much unburned gas is generated) can be grasped. From the NOx gas concentration discharged from the incinerator detected by the NOx gas concentration sensor 94, the concentration of NOx gas generated in the furnace (and by extension, 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 an incinerator configured to cool by water spray instead of a waste heat recovery boiler, the amount of heat generated in the furnace can be estimated based on the amount of water for water spray cooling instead of the amount of boiler evaporation.

The automatic combustion control is a control for comprehensively judging the above-mentioned in-combustion detection data and maintaining a stable 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 the gas supplied to each part by adjusting the first damper 81 to the third damper 83. Further, although not shown in FIG. 2, the control device 90 also adjusts the 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 is, for example, the speed at which the grate is advanced, the waiting time until the backward movement is started after the forward movement, the speed at which the backward movement is performed, the time interval of a series of operations, and the like. Further, although it is described in the present specification that "the grate is controlled" for the sake of simplicity, the control device 90 actually controls the drive unit of each grate. By controlling the various devices described above based on the various in-core detection data as described above, the combustion state in the furnace can be stably maintained for a long period of time. The combustion generated in the incinerator 10 varies greatly depending on the shape and structure of the incinerator 10 and the waste input. In addition, the target value for automatic combustion control also differs greatly depending on the durability of the incinerator 10, the required processing amount, the laws and regulations regarding exhaust gas, and the like. Therefore, the control device 90 comprehensively determines them and performs automatic combustion control.

<Primary combustion gas ratio adjustment control> The primary combustion gas ratio adjustment control is the supply amount of the primary combustion gas supplied via the grate and the primary combustion gas supplied without passing through the grate. It is a control that adjusts the ratio of the supply amount. In the present embodiment, by adjusting the second damper 82 and the fourth damper 84, the amount of primary air supplied to the combustion unit 12 via the combustion grate 22 (via the second supply path 71b). This is a control for adjusting the supply amount of the primary air supplied to the combustion unit 12 without passing through the combustion grate 22 (via the auxiliary supply path 71d). By performing the gas ratio adjustment control for primary combustion, the combustion state can be made substantially constant regardless of the presence or absence of the operation of the grate, and the combustion can be stabilized thereby.

First, it will be described with reference to FIGS. 3 and 4 that the combustion state fluctuates by the conventional method and the combustion cannot be stabilized. FIG. 3 is a conceptual diagram showing a state on the grate before and after the grate operation in the conventional example 1. FIG. 4 is a conceptual diagram showing a state on the grate before and after the grate operation in the conventional example 2.

The primary combustion gas supplied from below the grate (via the grate) passes through the gaps in the waste layer above the grate after passing through the grate. When the primary combustion gas passes through the waste, the waste around the passed gap is heated and reacts with oxygen in the air. As a result, the waste that comes into 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 is released from the surface of the waste. It is discharged upward. The pyrolysis gas also contains unreacted components in the air. After that, this pyrolysis gas causes a violent oxidation reaction by diffusion and mixing of oxygen molecules from the primary combustion gas containing oxygen in the furnace, and flame combustion occurs.

Here, as shown in FIG. 3, consider the case where the supply amount of the primary combustion gas is the same when the grate is stopped and when it is operated. Since the wastes move to each other when the grate is operated, even if the supply amount of the primary combustion gas supplied from under the grate is the same as shown in FIG. 3, the waste layer above the grate Contact with waste as it passes through the gaps inside is greatly promoted. As a result, the waste around the gap through which the air has passed is heated and contact-reacts with oxygen in the air, which promotes pyrolysis gasification and temporarily significantly increases the amount of pyrolysis gas generated. To do. As described above, since the pyrolysis gas contains a high concentration of unburned gas components, the amount of pyrolysis gas generated is significantly increased, and as shown in FIG. 3, a larger flame is generated. Combustion will occur. That is, when the grate is operating, large flame combustion is likely to occur. Therefore, combustion is not stabilized.

Next, as shown in FIG. 4, consider a case where control is performed to reduce the supply amount of the primary combustion gas supplied through the grate during the operation of the grate. The control shown in FIG. 4 is the control described in Patent Document 1. By reducing the amount of primary combustion gas supplied from under the grate, the contact between the primary combustion gas and waste is reduced, and the pyrolysis gas generated can be suppressed, so the waste that accompanies the operation of the grate. The effect of promoting the generation of pyrolysis gas due to mutual movement can be offset. Therefore, even when the grate is operating, only the same amount of pyrolysis gas is generated as when the grate is stopped. However, since the amount of primary combustion gas supplied from under the grate is only reduced, oxygen deficiency is caused in the flame combustion part formed by the pyrolysis gas, and the degree of flame combustion is reduced by that amount. Therefore, during the operation of the grate, it is not possible to maintain the combustion state in the state where the grate is stationary, and it is not possible to stabilize the combustion.

In consideration of the above, in the present embodiment, the following control is performed as shown in FIG. That is, the control device 90 reduces the supply amount of the primary combustion gas supplied through the grate in response to the start of the operation of the grate, and also via the auxiliary supply path 71d (fire without the grate). The first supply amount adjustment control for increasing the supply amount of the primary combustion gas to be supplied (from the lattice) is performed. Conceptually explaining the first supply amount adjustment control, the reduced primary combustion gas that was supposed to be supplied through the grate is supplied onto the grate without passing through the grate. .. As described with reference to FIG. 4, by reducing the amount of primary combustion gas supplied through the grate, the amount of pyrolysis gas generated can be made similar between when the grate is operating and when it is stopped. .. In the present embodiment, since the reduced amount of primary combustion gas is further supplied from the grate, the degree of flame combustion is determined when the grate is stopped without causing oxygen shortage at the flame forming portion of the pyrolysis gas. Since it can be maintained at the same level as the above, it is possible to maintain the combustion state in the state where the grate is stopped even though the grate is operating, and it is possible to stabilize the combustion. it can.

After that, the control device 90 performs a second supply amount adjustment control that restores the supply amount changed by the first supply amount adjustment control according to the end of the operation of the grate. That is, the supply amount of the primary combustion gas supplied through the grate is increased and restored, and the supply amount of the primary combustion gas supplied via the auxiliary supply path 71d is reduced and restored. As described above, the primary combustion gas ratio adjustment control is a process including the first supply amount adjustment control and the second supply amount adjustment control. By controlling the gas ratio adjustment for primary combustion, the amount of pyrolysis gas generated and the degree of combustion flame can be made the same when the grate is stopped and when it is operating, so combustion can be stabilized. it can.

In this embodiment, it is assumed that the supply amount of the primary combustion gas supplied through the auxiliary supply path 71d is zero when the grate is stopped, but this supply amount is not zero. May be good. In addition, the decrease (increase) of the primary combustion gas supplied through the grate and the increase (decrease) of the primary combustion gas supplied without the grate are close to each other to some extent. It is preferable, but it does not have to be exactly the same. In addition, "according to the start (end) of the grate operation" is not only at exactly the same timing as the start (end) of the grate operation, but also before and after the start (end) of the operation. It is a concept that includes the period of. For example, since there is a time lag between the start of the operation of the grate and the generation of the pyrolysis gas, the supply ratio of the primary combustion gas may be adjusted after a predetermined time from the start of the operation of the grate.

Further, 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 coordinated and combined. Specifically, the automatic combustion control manages and controls the gas ratio adjustment control for primary combustion, so that the gas ratio adjustment control for primary combustion is integrated with the automatic combustion control. Therefore, the value calculated independently by the gas ratio adjustment control for primary combustion is not used, and the above-mentioned in-core detection data used on the automatic combustion control side and the control data calculated by the automatic combustion control (state of each damper). The supply amount to be changed by the first supply amount adjustment control and the second supply amount adjustment control is adjusted based on (data for instructing the speed of the grate) and the like. Therefore, depending on the combustion state in the furnace, the amount of decrease (increase amount) of the primary combustion gas supplied through the grate and the amount of increase (decrease amount) of the primary combustion gas supplied without passing through the grate. ) Will increase or decrease.

Instead of this configuration, the amount of decrease (increase) of the primary combustion gas supplied through the grate and the amount of increase (increase) of the primary combustion gas supplied without the grate are predetermined. You can also. Hereinafter, this process will be described with reference to FIG. FIG. 6 is a timing chart relating to the supply of the primary combustion gas. The timing chart shown in FIG. 6 is an example, and each part may be operated at different timings.

In the example shown in FIG. 6, the timing for starting the primary combustion gas ratio adjustment control and how to change the supply amount are predetermined according to the operation timing of the grate. In the example shown in FIG. 6, the grate starts to move forward at time T1 and the position of the grate starts to change (that is, the grate switches from the stopped state to the operating state). At the same time, the first supply amount adjustment control is started. At this time, how to increase the supply amount of the primary combustion gas via the auxiliary supply path 71d is predetermined by the increase regulation line shown in FIG. The advance of the grate and the first supply amount adjustment control continue until time T2. Then, after a short waiting period, the grate starts to move backward at time T3. At the same time, the second supply amount adjustment control is started. At this time, how to reduce the supply amount of the primary combustion gas via the auxiliary supply path 71d is predetermined by the weight loss regulation line shown in FIG. After that, at time T4, the backward movement of the grate stops (that is, the grate switches from the operating state to the stopped state). At the same time, the second supply amount adjustment control ends.

As described above, the calculation amount can be reduced by predetermining the start timing and the supply amount of the first supply amount adjustment control and the second supply amount adjustment control. Further, by predetermining the optimum timing and supply amount, it is possible to exert the effect of stabilizing combustion at a high level while reducing the calculation amount.

In the example shown in FIG. 6, the grate is in the operating state from the time T1 to the time T4. Instead of this, for example, when the waiting time from the end of forward movement to the start of reverse movement is long, the grate is in the operating state from time T1 to time T2, and the grate is in the stopped state from time T2 to time T3. The grate may be defined as the operating state from T3 to time T4.

In the example shown in FIG. 6, both the increase regulation line and the decrease regulation are straight lines, but at least one of them may include a curve. Further, in the example shown in FIG. 6, the change mode at the time of increasing the weight (inclination in the case of a straight line) and the change mode at the time of decreasing the weight (inclination in the case of a straight line) are symmetrical, but may not be symmetrical.

As described above, the supply control method of the primary combustion gas of the present embodiment includes the transport unit 20, the air box (dry stage air box 25 to the post-combustion stage air box 27), the auxiliary supply path 71d, and the auxiliary supply path 71d. This is performed for the incinerator 10 provided with the above. The transport unit 20 is composed of a grate divided into a plurality of stages, and transports the waste toward the furnace outlet by operating intermittently with the waste loaded. The airbox is provided below each of the multi-stage grate, and the primary combustion gas for supplying into the furnace is supplied 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, for the grate of at least one constituent stage, the supply amount of the primary combustion gas supplied through the grate is reduced or increased according to the operation of the grate, and is assisted. Control is performed to increase or decrease the supply amount of the primary combustion gas supplied through the supply path 71d.

As a result, for example, the amount of pyrolysis gas generated is about the same as when the grate is not operating by reducing the amount of primary combustion gas supplied via the grate in response to the start of operation of the grate. At the same time, by increasing the supply amount of the primary combustion gas supplied without passing through the grate, the oxygen required for the flame combustion reaction (reaction of the pyrolysis gas) is supplied, so that the oxygen shortage can be prevented. Therefore, even during the operation of the grate, combustion is performed to the same extent as when it is not operating, so that the combustion can be stabilized.

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

Although the preferred embodiment of the present invention has been described above, the above configuration can be changed as follows, for example.

In the above embodiment, the supply amount of the primary combustion gas supplied through the grate and the supply amount of the primary combustion gas supplied through the auxiliary supply path 71d according to the start and end of the operation of the grate. , But if the timing corresponds to the operation of the grate, fire at another timing other than the start and end (for example, the timing determined based on the speed of the grate and the position of the grate). The configuration may be such that the supply amount of the primary combustion gas supplied via the lattice and the supply amount of the primary combustion gas supplied via the auxiliary supply path 71d are adjusted.

In the above embodiment, automatic combustion control and gas supply control for primary combustion are performed based on the incinerator gas temperature, the incinerator outlet gas temperature, the incinerator exhaust CO gas concentration, the incinerator exhaust NOx gas concentration, and the amount of boiler evaporation. Although it is configured to be performed, these controls may be performed using a part (at least one) of these incinerator detection data. Further, these controls may be performed by using the amount of water for spray cooling instead of the amount of evaporation of the boiler.

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 section 51). Instead of this, 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 composed of a three-stage grate consisting of a dry grate 21, a combustion grate 22, and a post-combustion grate 23. Instead of this, the transport unit 20 may be configured by a grate other than the three stages. For example, the dry grate 21 may be omitted, and the transport unit 20 may be composed of a combustion grate 22 and a post-combustion grate 23.

10 Incinerator (grate type waste incinerator)
11 Dry part 12 Combustion part 13 Post-combustion part 21 Dry grate 22 Combustion grate 23 Post-combustion grate 25 Dry stage air box 26 Combustion stage air box 27 Post-combustion stage air box 71 Primary air supply path 71a First supply path 71b 2nd supply path 71c 3rd supply path 71d Auxiliary supply path 90 Control device

Claims (8)

It is composed of a grate divided into multiple stages, and has a transport unit that transports the waste toward the furnace outlet by operating intermittently with the waste loaded.
A wind box, which is provided below each of the multiple stages of the grate and is supplied with a gas for primary combustion to be supplied into the furnace via the grate,
Without passing through the grate, and the auxiliary supply path for supplying the primary combustion gas to the inside of the flame rather than outside of the flame is on the grate of the furnace,
In the method of controlling the supply of gas for primary combustion of a grate-type waste incinerator equipped with
For the grate of at least one constituent stage
Depending on the operation of the grate, the supply amount of the primary combustion gas supplied through the grate is reduced or increased, and the supply amount of the primary combustion gas supplied through the auxiliary supply path is increased or decreased. A method for controlling the supply of a gas for primary combustion, which is characterized by performing control. The method for controlling the supply of primary combustion gas according to claim 1.
The first is to reduce the supply amount of the primary combustion gas supplied through the grate and increase the supply amount of the primary combustion gas supplied through the auxiliary supply path according to the start of the operation of the grate. Supply amount adjustment control and
A second supply amount adjustment control that restores the supply amount changed by the first supply amount adjustment control according to the end of the operation of the grate, and
A method for controlling the supply of a gas for primary combustion, which comprises performing. The method for controlling the supply of primary combustion gas according to claim 2.
In the first supply amount adjustment control, the supply amount of the primary combustion gas supplied through the auxiliary supply path is increased according to a predetermined increase regulation line.
The second supply amount adjustment control is a method for controlling the supply of the primary combustion gas, which comprises returning the supply amount of the primary combustion gas supplied through the auxiliary supply path according to a predetermined weight loss regulation line. .. The method for controlling the supply of primary combustion gas according to claim 1 or 2.
In the grate type waste incinerator, the gas temperature in the incinerator, the gas temperature at the incinerator outlet, the CO gas concentration discharged from the incinerator, the NOx gas concentration discharged from the incinerator, the evaporation amount of the boiler due to the recovery of heat from the exhaust gas, and the water spray. Based on the detection data in the furnace, which is at least one of the amount of cooling water, automatic combustion control is performed to control the grate-type waste incinerator to stabilize the combustion state.
Using at least one of the in-fire detection data used in the automatic combustion control and the control data calculated by the automatic combustion control, the supply amount of the primary combustion gas supplied through the grate and the auxiliary A method for controlling the supply of primary combustion gas, which comprises adjusting the supply amount of primary combustion gas supplied through a supply path. By controlling the grate-type waste incinerator by using the primary combustion gas supply control method according to claim 4, the amount of evaporation of the boiler connected to the grate-type waste incinerator is stabilized. 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 by using the evaporation amount stabilization method according to claim 5. In a grate-type waste incinerator that incinerates waste while transporting it by a grate
It is composed of the grate divided into multiple stages, and has a transport unit that transports the waste toward the furnace outlet by operating intermittently with the waste loaded.
A wind box, which is provided below each of the multiple stages of the grate and is supplied with a gas for primary combustion to be supplied into the furnace via the grate,
Without passing through the grate, and the auxiliary supply path for supplying the primary combustion gas to the inside of the flame rather than outside of the flame is on the grate of the furnace,
Control device and
With
The control device relates to the grate of at least one constituent stage.
Depending on the operation of the grate, the supply amount of the primary combustion gas supplied through the grate is reduced or increased, and the supply amount of the primary combustion gas supplied through the auxiliary supply path is increased or decreased. A grate-type waste incinerator characterized by being controlled. The grate type waste incinerator according to claim 7.
The control device
The first is to reduce the supply amount of the primary combustion gas supplied through the grate and increase the supply amount of the primary combustion gas supplied through the auxiliary supply path according to the start of the operation of the grate. Supply amount adjustment control and
A second supply amount adjustment control that restores the supply amount changed by the first supply amount adjustment control according to the end of the operation of the grate, and
A grate-type waste incinerator characterized by performing.

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