JP4448799B2 - A waste combustion state detection method using a grate temperature in a stoker type incinerator, a waste incineration control method and a grate temperature control method using the method. - Google Patents

Description

  The present invention relates to an improvement in a waste combustion control system for a stoker-type waste incinerator that incinerates waste such as municipal waste, and detects a change in the combustion state of waste from a grate surface temperature at an early stage, and the interior of the waste layer. By using the grate temperature detection method using the grate temperature, which can quickly respond to changes in the waste combustion state and always perform stable waste combustion by grasping the progress state of The present invention relates to a garbage combustion control method and a grate temperature control method.

  A stoker-type waste incinerator that incinerates waste such as municipal waste generally has a basic structure of a waste combustion control system as shown in FIG. 16, and is supplied to the furnace by a dust supply device 37 from a hopper 36. W is incinerated via the dry stoker 31, the combustion stoker 32, and the post-combustion stoker 33, and becomes incinerated ash Wo and discharged from the discharge port 39 to the outside of the furnace.

The primary combustion air A ₁ , A ₂ , A ₃ of the waste W is supplied from the primary combustion air supply device 38 via the dampers 54a to 54d, and combustion is completed at the preset burnout point Qa. Control is performed so that the so-called extra combustion is completed at the completion point Qb.

That is, the combustion amount of the waste W is controlled mainly by the supply amount of the waste W in the furnace, the supply amount of the primary combustion air A ₁ , A _2, and A ₃ and the primary combustion air temperature. The supply amount of the waste W is controlled by adjusting the operating speed of the dust supply device 37, the dry stalker 31, the combustion stalker 32, etc. with the stalker speed adjusting device 18, and the supply amount of the primary combustion air and The temperature is adjusted by the primary combustion air supply device 38, dampers 54a to 54d, air preheaters 43a and 43b, and the like.

  More specifically, signals from dust layer level sensors 50a, 50b, 50c installed on the furnace side wall and cameras (not shown) installed in front of the furnace, signals from furnace gas temperature sensor (not shown), burnout inspection Using the information indicating the combustion state of the dust such as a signal from the ejector 51, the operation of each of the stalkers 31, 32, 33 and the dust feeder 37 is controlled via the stalker speed adjusting device 48, and the thickness of the dust layer is controlled. In the case where the temperature rises, the speed of the dust supply device 37 or the stalker on the upstream side is decreased to reduce the thickness of the dust layer. Further, when the burnout point Qa comes to the downstream side, it is returned to a predetermined position by slowing the stalker speed.

In addition, a predetermined amount of waste combustion is achieved by using information for detecting the amount of waste combustion, such as the waste input weight, the amount of steam generated in the waste heat boiler 35 (or the amount of gas cooling water injection), and the exhaust gas flow rate. the primary combustion air amount required is calculated and supplied as the primary combustion air a ₁ to a _3. In general, combustion control is performed so that the amount of combustion of the waste is kept constant. However, in a plant that generates power by collecting the combustion heat of the waste with the waste heat boiler 35, a stable power generation amount is obtained. In order to obtain this, it is particularly required to keep the steam generation amount (that is, the combustion heat amount) constant, and as a result, the necessity to keep the waste combustion heat amount constant is increased.

Therefore, normally, the air amount calculation device 46b is set from the set value from the target combustion amount setting device 45 and the calculated value of the combustion amount calculated by the combustion amount calculation device 44 using the detection value of the dust supply amount detector 49a. And the required air amount corresponding to the amount of steam generated by the boiler 35 is calculated by the air amount calculation device 46a from the signal of the steam flow detector 49b, and the calculation from both the air amount calculation devices 46a and 46b. The primary combustion air A _{1 to} A ₃ is controlled by adjusting the opening degree of each of the dampers 54 a to 54 d via the combustion air amount adjusting device 47 according to the signal.

The conventional combustion control system of the stoker-type waste incinerator as shown in FIG. 16 is highly efficient and stable when the so-called waste quality such as the component of the waste W to be incinerated, the calorific value, and the moisture content is substantially constant. The waste can be burned.
However, as described above, when it is necessary to perform control for keeping the input heat amount of the waste W at a set value, such as the evaporation amount control, if the waste quality changes, the supply amount of the waste W also greatly changes. As waste quality decreases, the amount of waste supply increases and the layer thickness of waste on each stoker increases.

  If the dust layer thickness is increased, the dust layer thickness is adjusted by changing the operating speed of the upstream side dust supply device 37 and the stalker by the stalker speed adjusting device 48. However, the adjustment of the feeding device 37 and the stalker operating speed by the stalker speed adjusting device 48 has a fundamental weak point that the response speed is slow. As a result, the dust layer thickness is not sufficiently corrected, and the primary combustion air As a result, the burnout point Qa fluctuates and the burnout point Qa greatly fluctuates, which has a problem of adversely affecting the heat loss of the ash Wo and the secondary combustion.

  In Fig. A, 34 is a secondary combustion chamber, 40 is an exhaust gas purification device, 41 is an induction fan, 42 is a chimney, 52 is a combustion completion point detector, 53 is a burnout point detector, and 55 is automatic combustion control. Device.

  As described above, there is a basic problem in the waste combustion control of the conventional stoker-type waste incinerator that the response of the control to the excess or deficiency of the combustion amount of the waste due to the excess or deficiency of the waste combustion amount or the change of the waste quality is low. . These problems are all caused by sensors (for example, dust layer level sensors 50a to 50c and in-furnace gas temperature sensors) that detect the combustion state of the dust, and sensors (for example, exhaust gas) that detect the combustion amount of dust. A flow sensor, a steam flow detection sensor 49b, etc.) are types that monitor waste from the outside, or types that detect events related to exhaust gas generated as a result of the combustion of dust, such as drying on a stoker or It can be said that this is due to the fact that it is not a type of sensor that directly monitors the interior of the dust layer during combustion. This is because if the internal state of the dust layer on the stoker cannot be directly grasped, the sensor will actually detect the excess or deficiency after the symptom of the excess or deficiency of the combustion amount (or combustion heat) appears inside the dust layer. This is because the action to be taken in order to adjust the excess / deficiency is delayed by the time until the detection of, and as a result, fluctuations in the combustion state and the like become larger.

  On the other hand, as a measure to improve the responsiveness of combustion control by grasping the state inside the dust layer early, detect either or both of the temperature distribution and the dust thickness distribution of the grate of the stoker type incinerator, Using this, the combustion control method (Japanese Patent Laid-Open No. 2001-248819) so as to control the total combustion air flow rate, the exhaust gas temperature at the furnace outlet and the temperature measurement value of the grate in the combustion zone after the grate, Combustion by controlling the combustion position of the waste at a position where mixing of the exhaust gas at the furnace outlet is good while maintaining the exhaust gas temperature at the furnace outlet within an appropriate range by adjusting the opening degree of the damper for blowing the combustion air A control method (Japanese Patent Laid-Open No. 2000-320824) and the like are disclosed.

  JP-A-2001-248819 discloses an a. Since the grate directly receives heat transfer from the combustion part of the garbage, it is possible to obtain the distribution of the combustion state of the garbage in the furnace without time delay from the temperature of the grate and b. The feature is that no special new technology is required for installation. Specifically, the present invention calculates the average value of the grate temperature of each control divided region of the stoker surface using these features, and the average value of the grate temperature is in a good combustion state. When the temperature is lower than the temperature range, the post-combustion air amount is increased, and when the temperature is higher, the post-combustion air amount is decreased.

However, in Japanese Patent Laid-Open No. 2001-248819, although the strength and weakness of dust combustion on the grate can be detected quickly by using the grate temperature, it is only the garbage that is judged from the detected value of the grate temperature. Only the strength of the combustion, only the state inside the dust layer (for example, whether it is mainly volatile gas combustion or fixed carbon combustion), and the excess or deficiency of combustion heat No adjustment control is performed on the above.
As a result, in Japanese Patent Laid-Open No. 2001-248819, although the control response of the combustion air amount is slightly increased, the state inside the dust layer on the stoker is not detected at all. There is a problem that it is impossible to adjust and control (garbage quality fluctuation) more quickly.

In addition, the said Unexamined-Japanese-Patent No. 2000-320824 is substantially the same as Unexamined-Japanese-Patent No. 2001-248819, and the opening degree adjustment of a combustion air blowing damper is performed using the temperature measurement value of the grate which forms a post-combustion zone. Therefore, the intensity of dust combustion on the stoker can be detected quickly, and as a result, the control response of the combustion air amount is improved.
However, since the state inside the dust layer on the stoker is not detected at all from the detected value of the grate temperature, quicker adjustment and control can be performed for fluctuations in the combustion state and fluctuations in the amount of combustion heat. There is no problem.

JP 2002-206722 A JP 2001-248819 A JP 2000-320824 A

  The present invention relates to the above-mentioned problems in the combustion control of a conventional stoker-type waste incinerator, i. Since all of the various sensors that make up combustion control are not the type of sensors that directly monitor the inside of the dust layer on the stoker, the adjustment and control for excess and deficiency of the combustion amount and combustion heat amount will be delayed. And fluctuations in the amount of thermal combustion, etc., b. Even in the method of controlling the combustion air amount using the temperature detection value of the stalker, although the control response of the combustion air amount can be simply improved, the automatic combustion control system including the control of the combustion amount and the combustion heat amount It is intended to solve problems such as the inability to improve overall responsiveness. By making it possible to detect the state of the dust layer on the stoker from the measured temperature value of the stoker, As a result of the delay in the response to the adjustment of the excess / deficiency by the time from when a sign of excess / deficiency of combustion heat appears inside the dust layer to the actual detection of the excess / deficiency by the sensor, combustion fluctuations increase Provides a method for detecting the state of combustion using a grate temperature in a stoker-type waste incinerator, a method for controlling the combustion of a garbage and a method for controlling the grate temperature using the same. It is an object of the invention to Rukoto.

The invention of claim 1 is a stoker-type waste incinerator that performs combustion control using a grate temperature, and targets one or more temperatures for each grate for a plurality of grate at the whole stoker. Based on the heat transfer cooling characteristics of the grate related to the relationship between the surface temperature of the grate upper wall, the grate ventilation, and the heat passing through the grate From the average temperature and ventilation rate of each grate, the grate passing heat amount is calculated. Based on the relationship in which the grate passing heat amount is directly proportional to the waste heat generation amount, the calculated value of the grate passing heat amount It is a basic configuration of the invention to grasp the increase and decrease of the calorific value.

The invention according to claim 2 is a stoker-type waste incinerator that performs combustion control using a grate temperature, and targets at least a grate tip and a grate for each grate for a plurality of grate at the whole stoker. with measuring the temperature of the two positions of the intermediate portion of the upper wall, wherein the temperature difference between the temperature measured in the upper wall surface of each grate in the grate vicinity, or volatile combustion, or surface combustion, or a volatile combustion The basic configuration of the present invention is to grasp the combustion mode of whether surface combustion occurs simultaneously or not and detect the progress of waste combustion based on the recognized combustion mode.

According to a third aspect of the present invention, there is provided information relating to the calorific value of the combustion product ascertained by the method for detecting waste combustion state of claim 1 and information relating to the progress of waste combustion detected by the method for detecting waste combustion state of claim 2. The basic configuration of the present invention is that at least one of the waste supply speed, the stoker speed, the primary combustion air amount, and the primary combustion air distribution ratio is adjusted using either one or both.

According to a fourth aspect of the present invention, in the third aspect of the invention, information relating to the boiler steam flow rate, the burnout point position, and the dust layer thickness is used together.

According to a fifth aspect of the present invention, there is provided a grate ventilation system using at least one of the grate temperature detected by the dust combustion state detection method of the first aspect, the calculated value of the calorific value passing through the grate, or the information related to the calorific value of the combustion product. The basic configuration of the invention is to adjust the amount.

The invention of claim 6 uses the grate temperature detected by the dust combustion state detection method of claim 2 or at least one of the information concerning the grasped dust combustion form or the progress of dust combustion, and the ventilation amount of the grate It is a basic configuration of the invention to adjust the above.

  In the present invention, a state such as dust combustion in the vicinity of the grate (that is, on the wall surface on the grate) is directly detected in the vicinity of the grate based on the temperature measurement value. Therefore, the timing for detecting the change in the combustion state is earlier than any other detection sensor or detection system, and more accurate detection can be performed. Thereby, the required control operation can be performed more quickly, and as a result, the fluctuation range of the combustion amount or the like can be greatly reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic plan view of a stoker part of a stoker type incinerator according to the present invention, and a so-called dry stoker D, a combustion stoker C, and a post-combustion stoker B form a stoker part.

That is, the stalker section has 10 stalker rows arranged side by side in the width direction, and a dry stalker D comprising a total of 24 movable stalker rows and fixed stalker rows in the vertical width direction, combustion A stalker C and a post-combustion stalker B are juxtaposed.
Each stoker column is formed by combining a movable grate S ₁ as shown in FIG. 2 and the fixed grate S _2, the movable grate S ₁ is reciprocally moved in the arrow b direction The garbage on the stalker (not shown) is sequentially fed forward (to the left).

Primary combustion air A ₁ · A ₂ · A ₃ is supplied from the lower the grate S ₁ · S ₂ as shown in FIG. 3, and travels laterally in the stoker in the arrow B direction, each grate S ₁ -It is ejected from the tip of S ₂ into the waste W on the stoker.
In addition, since the stoker part of the stoker type waste incinerator is already publicly known (for example, Unexamined-Japanese-Patent No. 2002-31322 etc.), the detailed description is abbreviate | omitted here.

  FIG. 5 is a block diagram showing the basic configuration of the method for detecting the combustion state of dust according to the present invention. The method for detecting the combustion state of dust according to the present invention includes a grate temperature measuring unit 1, a combustion air amount measuring unit 2, a fire It consists of a lattice air flow rate calculation unit 3, a grate passing heat amount (heat reception amount) calculation unit 4, a grasp / measurement unit 5 for the state in the dust layer, and an incinerator operation control unit 6.

  The grate temperature measuring unit 1 measures the average temperature of the upper wall surface of the grate S, and preferably averages the measured values of as many points as possible on the upper wall surface of the grate S. If they are unified, even if only one point of temperature measurement is performed on one grate S, there is no practical problem.

  The combustion air amount measuring unit 2 measures the amount of primary combustion air supplied to a stalker unit composed of a large number of grate groups, and uses the measured ventilation rate from the combustion air amount measuring unit 2. Thus, the grate ventilation amount calculation unit 3 calculates the grate ventilation amount that passes through the lower surface space of each grate.

Further, the grate passing heat amount (grate received heat amount) calculating unit 4 calculates the grate passing heat amount using the average temperature of the upper wall surface of the grate S and the calculated grate ventilation amount.
For example, the upper wall surface of another grate S is heated by an electric heater, and air is flowed to the lower surface space portion of the grate S to cool it, and the inlet temperature, outlet temperature, and air flow rate at this time are set. The heat transfer and cooling characteristics of the grate are investigated in advance by measurement. That is, it is possible to determine the amount of heat taken away by air = the amount of heat passing through the grate from the air inlet temperature, the outlet temperature, and the air flow rate. As a result, a. The average temperature of the grate upper wall, b. Grate ventilation and c. Interrelationship of the amount of heat passing through the grate can be grasped.

On the other hand, even during operation of the stoker-type waste incinerator, the a. B. And c. In view of the mutual relationship of The average temperature of the wall on the grate and b. Knowing the two amounts of the grate ventilation, the c-grate passage heat quantity can be obtained.
The grate-passing heat amount calculation unit 4 calculates the grate-passing heat amount from the average temperature of the upper wall surface of the grate and the grate ventilation amount based on the logic as described above.

At the same time, if the temperature distribution on the upper wall surface of the grate S is known, it is possible to judge the combustion state of the dust near the grate.
That is, the waste W is composed of three components, moisture, combustible component, and ash, and the combustible component is divided into volatile component and fixed carbon. In the stoker incinerator, a. The water evaporates from the garbage and is dried. Volatiles burn as combustible gas. Also, c. Fixed carbon (char) burns on the surface and burns in the order of ash.
Combustion of the garbage is performed in each stage a. B. C. Does not proceed to the next stage after each is completed. Before the drying stage is completed, b. Each stage a. B. Although c overlap and occur, these orders will not be reversed.

  As a result, the a. In the stage before combustible gas is generated during drying, there is nothing to burn, so the grate temperature will not rise even if air is introduced. In addition, b. In the stage where the volatile matter of the gas is burned as combustible gas, the particle size of the solid is still large, as shown in FIG. 3, and the air emitted from the tip of the grate S is mixed with the combustible gas and the gap between the solid particles Burns in. Since the combustion gas flows lightly upward at a high temperature, the tip of the grate S is mainly heated.

On the other hand, said c. At the stage where the fixed carbon is subjected to surface combustion, the particle size of the solid is small and small, and the air emitted from the grate S burns on the surface of the solid particle together with the fixed carbon. Therefore, the part which hits the back of the grate S (the center part of the upper wall surface) is also heated.
That is, by measuring the temperature difference between at least the tip part and the back part of the grate S, it can be determined whether volatile combustion or surface combustion is occurring near the grate or whether combustion is not occurring. In other words, by installing a plurality of temperature detectors on one grate, the content of the combustion state (whether volatile combustion or surface combustion is occurring, from the temperature detection value even during operation of the actual furnace, Alternatively, it can be ascertained whether or not both occur simultaneously or whether combustion occurs.

  In the dust layer state grasping / determining unit 5 in FIG. 5, the state (for example, the contents of the combustion state) in the dust layer is grasped and judged from the temperature detection values at at least two locations on the upper wall surface of the grate. Is done.

In other words, even during the operation of an actual stoker-type waste incinerator, by detecting the temperature of at least two locations on the wall surface of the grate, the amount of heat passing through the grate S (heat received amount) and the combustion state in the vicinity of the grate are detected. Is possible.
The amount of heat passing through the grate S is closely related to the amount of heat generated by the waste W.
Further, the combustion state (combustion form) in the vicinity (upper wall surface portion) of the grate S is closely related to the progress of W on the garbage stoker.

Accordingly, the information from the grate passing heat amount calculation unit 4 and the in-dust combustion state grasp determination unit 5 can quickly and reliably grasp the amount of heat generated from the waste and the progress of the waste incineration, and the stoker-type waste incinerator. In the operation control unit 6, for example, a. When the amount of heat generated from the waste on the dry stoker D decreases, increase the amount of waste supplied to keep the input heat constant, and b. When the progress of waste incineration is delayed, increasing the supply amount of air A ₁ to the drying stoker D to promote drying; c. When the progress of the waste incineration is delayed on the combustion stalker C, a specific control operation such as decreasing the stalker speed and holding the burnout point at a fixed position is performed.

Incidentally, the operation means (control means) itself taken for the change in the combustion state is exactly the same as the conventional combustion control method for the stoker-type waste incinerator.
However, in the present invention, since the state of the upper wall surface of the grate S is directly detected (that is, directly detected in the vicinity of the grate), the timing for detecting the change in the combustion state or the like is the conventional timing. It is faster than any detection sensor or detection system, and allows for quicker control operations. As a result, the so-called fluctuation amount of the combustion amount is greatly reduced.

With reference to FIG. 1, in this embodiment, the dry stoker D, the combustion stoker C, and the post-combustion stoker D are each formed by combining a total of 80 movable grate and fixed grate, which will be described later. Thus, dry stoker D detects the temperature at the tip and top center of the grate with numbers D _{1 to} D ₄ , and combustion stoker C with the grate with numbers C _{1 to} C ₄ , respectively. Temperature detectors (not shown) are provided, and the temperatures of the tips and top center (back) of each grate D _{1 to} D ₄ , C _{1 to} C ₄ , and B _{1 to} B ₄ are Each has been detected.

Note that the number of grate and the position of the grate for temperature detection are selected as appropriate so that the combustion state of the dust in the direction of the dust flow can be grasped. In this embodiment, one row is formed at the center of the stoker. in it are arranged a grate for measuring the temperature may be in two rows or three rows shape as to be arranged to be temperature measurement grate.

  Further, the temperature detector for detecting the temperature of the tip portion of the grate S and the central portion (back portion) of the upper wall surface may be of any type. Furthermore, the temperature detector may be embedded and fixed inside the grate upper wall plate.

In FIG. 1, assuming that Tc ₁ a is the tip temperature of the grate C1 and Tc ₁ b is the back temperature of the grate C1, grasping / determination of the state in the dust layer in order to estimate the progress of the combustion state The temperature difference ΔTc ₁ used in the unit 5 can be defined by ΔTc ₁ = Tc ₁ a−Tc ₁ b.
Now, when the temperature difference ΔT is displayed including not only the combustion stalker B but also the dry stalker D and the post-combustion stalker D, the temperature difference ΔT changes with the progress of combustion, and shows the transition as shown in FIG. become.

  FIG. 7 shows an example of the distribution of the grate temperature difference ΔT in the stoker of FIG. 1, where x indicates the initial state of the incinerator operation, and − (solid line) indicates the case where the progress state of combustion is accelerated. The state --- (dotted line) indicates the state when the progress of combustion is delayed.

With reference to FIG. 7, in the initial stage of operation, the center of gasification combustion is the grate D4, the center of surface combustion is the grate C4, and after the grate B2 is in the state of ash.
When the distribution of ΔT changes from the initial state of x to the distribution shown by the solid line, the center of gasification combustion is D3 and the center of surface combustion is the grate C2, and the state of progress of combustion is accelerated. It is. This change can be detected by an increase in ΔT _D2 or ΔT _D3 or a decrease in ΔT _C1 or ΔT _C2 .
Conversely, the state indicated by the dotted line indicates a state in which the progress of combustion is delayed, and this state can be detected by a decrease in ΔT _D2 or ΔT _D3 or an increase in ΔT _C1 or ΔT _C2 .

It should be noted here that the measured value of the grate D4 decreases in any case, and the same is true for both the early and late combustion conditions when the distribution of ΔT is in the vicinity of the maximum or minimum. The nature of change. In order to make a correct determination, it is necessary to determine which grate S changes to be noted in consideration of the overall distribution of ΔT.
In the actual furnace control, in this example, paying attention to the grate D3, if ΔT _D3 increases, the operation of delaying combustion (decreasing the amount of dry stoker air, increasing the dry stoker speed, etc.), ΔT _D3 is If it decreases, operations to accelerate combustion (increase dry stoker air volume, decrease dry stoker speed, etc.) are performed.

Next, calculation of the amount of heat passing through the grate will be described. Now, the average temperature T _C1 used for the calculation of the amount of heat passing through the grate is expressed as follows for the grate C1.
T _C1 = (T _C1a + T _C1b ) / 2
Further, F _C1 the amount of air flowing through the grate C1, when the amount of heat passing through the grate C1 and _{Q C1 Q C1 = f (T} C1, F C1)
FIG. 8 is a graph showing an example. As is clear from FIG. 8, there is a relationship that the greater the amount of air and the higher the grate temperature, the higher the amount of heat passing through the grate. The gradient of the graph changes with parameters such as dust quality and grate characteristics (shape, cooling efficiency, etc.). FIG. 8 shows an actual measurement of a grate having a width of 160 mm (manufactured by Takuma Co., Ltd.).

  As described above, the amount of heat Q passing through the grate is closely related to the amount of heat generated by the waste W. Therefore, if the amount of heat Q passing through the grate is monitored, the increase or decrease in the amount of heat generated by the waste W can be determined.

FIG. 9 shows an example of the distribution situation of the grate average temperature T in the stoker of FIG.
As can be seen from FIG. 9, the grate temperature naturally increases in the combustion zone C. In the example of FIG. 1, the grate D1 in which combustion has not started at all is normal temperature, and the grate D4 (gasification combustion center) to the grate C4 (surface combustion center) has a higher temperature than the others. ing. Here, in the grate B2 to the grate B4, the temperature is about 150 ° C. despite the end of the combustion, in order to reduce the unburned residue in the ash from the grate B1 to the grate B4. Moreover, it is because the air near 150 degreeC is ventilated.

When the grate passing heat quantity Q is calculated from the data of FIG. 9, it is as shown by x (initial state) of FIG.
Referring to FIG. 10, consider a case where the distribution of the amount of heat passing through the grate Q has changed from the initial state of x to the distribution shown by the solid line. In this case, the amount of heat Q passing through the grate in the combustion zone (D4 to C4) is increased, and the amount of heat generated by the dust is increased.
This change can be detected by an increase in T _{D4 to} T _C4 , and changes occur in order from the upstream side (in the order of grate D4 → grate C1 → grate C2 →...).
On the contrary, the state indicated by the dotted line is a state in which the amount of heat generated by the dust is reduced, which can be detected by a decrease in T _{D4 to} T _C4 and changes sequentially from the upstream side.

In the control to keep the input heat amount constant in the actual furnace, paying attention to the grate D4 and grate C1 in which changes appear early, the operation to reduce the waste supply amount as T _D4 and T _C1 increase (in the waste supply device In _contrast , if T _D4 and T _C1 decrease, an operation of increasing the amount of waste supply (increasing the speed of the waste supply device) is performed.

In an actual stoker-type waste incinerator, a change in combustion state (change in the progress of combustion) and a change in waste quality often occur at the same time.
Specifically, consider a case where the initial state of x in FIGS. 11 and 12 changes to the state indicated by the solid line. First, the position of the combustion zone from the grate D4 to the grate C4 moves to the grate D3 to the grate C3. Next, the value of the grate passing heat quantity Q is increased from about 600 to about 700. Therefore, this indicates that the progress of waste combustion is accelerated and the amount of heat generated in the waste is increased, and the operation of reducing the waste supply amount is performed simultaneously with the operation of delaying the combustion.

  What should be noted here is a change in the amount of heat Q passing through the grate of the grate D3. Although it has changed greatly from about 150 to about 700, this is greatly influenced by the fact that the combustion state at the position of the grate D3 has changed from the middle of drying to the center of gasification combustion. As described above, in order to make a correct judgment, it is necessary to determine which grate change to focus on in consideration of the overall distribution.

Next, the Example regarding the control method of a grate temperature is described. FIG. 13 is a diagram showing an example of the relationship between the primary combustion air amount of the stoker-type waste incinerator and the average grate temperature (air temperature 20 ° C.).
As described above, the grate average temperature T is closely related to the heat generation amount Qo of the waste. When analyzing the operation data of the actual furnace, the passing heat amount Q is directly proportional to the waste heat generation amount Qo and It has been confirmed in practice that it is almost constant.
Therefore, if the heat generation amount Qo of the dust is constant, as can be seen from the relationship of FIG. 13, it can be seen how much the grate average temperature T can be lowered by how much the air amount is increased.

For example, it is assumed that the amount of air supplied to the combustion stoker F _C1 = 20 m3 N / h and the average temperature T _C1 = 440 ° C. when the standard waste is incinerated. It has been empirically found that the grate temperature T _C1 exceeds 400 ° C., so that wear rapidly proceeds. Therefore, it is desirable to operate the grate temperature T _C1 at 400 ° C. or less. For that purpose, it is necessary to keep F _C1 at about 25 m3 N / h or more from FIG.
In addition, when the waste W is changed to high quality waste, it can be understood that F _C1 may be maintained at about 43 m 3 N / h or more.
In addition, if priority is given to the protection of the grate S, it should be kept at 300 ° C. or lower, at 45 m3 N / h or higher for standard waste, and 81 m3 N / h or higher for high-quality waste. good.

Such a method for controlling the grate average temperature has been empirically performed so far, but by grasping the relationship as shown in FIG. 13, automatic control can be performed and the grate average temperature is set. In order to lower the temperature, it is possible to prevent the furnace temperature from being lowered by increasing the amount of air more than necessary.
It should also be noted here that, as can be seen from FIGS. 10 and 12, the relationship of FIG. 13 changes with the progress of combustion, and in order to make a correct judgment, the entire distribution is considered. Therefore, it is necessary to grasp how far combustion has progressed.

FIG. 14 shows a more specific example of the control system of the stoker type incinerator implementing the present invention. FIG. 15 shows the grate temperature difference ΔT when the control system of FIG. Specific values such as the grate passage temperature Q are shown.
FIG. 15 shows the relationship between the grate temperature difference ΔT, the grate passing heat quantity Q, the air quantity and the grate temperature measured using the standard waste for the stoker furnace (made by Takuma Co., Ltd.) shown in FIG. FIG.

Referring to FIG. 14, from the measured value 1a of the grate temperature measuring unit 1, the measured value 2a of the combustion air amount measuring unit 2, the calculated value 3a of the grate ventilation amount calculating unit 3, etc. Temperature difference ΔT _{D1 to} ΔT _B4 , grate average temperature T _{D1 to} T _B4 , grate ventilation rate F _{D1 to} F _B4, and grate average temperature T _{D1 to} T _B4 and grate ventilation rate F _{D1 to} F B obtaining an operation value Q _D1 to Q _B4 grate ventilation heat by the grate passes through heat calculation unit 4 using _B4.
Then, the combustion state 5a is grasped by the dust layer state grasping / determining section 5, and the calorific value (garbage quality) 4a of the combustion product (garbage) from the calculated values Q _{D1 to} Q _{B4 of the} grate passing heat amount. And adding other information (boiler steam flow rate, burn-out point, dust layer thickness) 7a to the information 5a, 4a and 7a to the automatic combustion control device (incinerator operation control unit 6). It is configured to input and adjust and control each operating device of the waste incinerator.
In addition, each measured value, each calculated value, control operation | movement, etc. in the control system more concrete of FIG. 14 are as having shown to (a)-(f) of FIG.

  The present invention can be applied not only to a stoker-type incinerator that incinerates garbage but also to all stoker-type combustion furnaces that handle various combustibles.

It is a plane schematic diagram of the stoker part of the stoker type garbage incinerator concerning the present invention. It is a vertical cross-sectional outline | summary of a stalker, and shows an example of the combination of a movable grate and a fixed grate. It is explanatory drawing of the flow state of the primary combustion air supplied from the downward direction of the stoker. (When combustion of combustible gas is the main). It is explanatory drawing of the flow state of the primary combustion air supplied from the downward direction of the stoker (when the surface combustion of solid carbon is a main body). It is a block block diagram which shows the refuse combustion state detection method of this invention. It is a diagram which shows the relationship between the temperature difference (DELTA) T of a grate upper wall surface, and the progress state of a combustion state. It is a diagram which shows distribution of the temperature difference (DELTA) T of the grate upper wall surface in the stoker of FIG. It is a diagram which shows the relationship between the grate temperature, the amount of air, and the amount of heat passing through the grate (when the air temperature is 20 ° C.). It is a diagram which shows an example of distribution of the grate average temperature T. FIG. It is a diagram which shows the grate passage calorie | heat amount Q computed from the data of FIG. It is a diagram which shows the distribution condition of grate temperature difference (DELTA) T. It is a diagram which shows the distribution condition of the grate passage calorie | heat amount Q. FIG. It is a diagram which shows the relationship between the amount of primary combustion air of a stoker-type waste incinerator, and a grate temperature. It is a block block diagram which shows the specific example of the control system of this invention. FIG. 15 shows a specific example of each control value in the control system of FIG. 14, (a) is a display content of a symbol, (b) is an arrangement of grate (same as FIG. 1), and (c) is a standard garbage. Distribution of temperature difference ΔT between grate tip and back, (d) distribution of grate passing heat quantity Q in reference garbage, (e) relation between air quantity and grate temperature in reference garbage, (f) FIG. 4 is an explanatory diagram of a specific control target, its operation status, countermeasures, and operation contents. 1 shows an example of a basic configuration of a waste combustion control system in a conventional stoker-type waste incinerator.

Explanation of symbols

D Dry Stoker C Combustion Stoker B Post Combustion Stoker S Grate S ₁ Movable Grate S ₂ Fixed Grate D _{1 to} D ₄ Temperature Measurement Target Grate C _{1 to} C ₄ Temperature Measurement Target Grate B _{1 to} B ₄ Temperature Measurement Target grate 1 Grate temperature measuring part 2 Combustion air quantity measuring part 3 Grate air flow rate calculating part 4 Grate passing heat quantity (grate heat receiving quantity) calculating part 5 Recognizing / determining the state in the dust layer 6 Incinerator operation control ΔT Temperature difference between grate tip and grate back T _1a Grate tip temperature T _1b Grate back temperature T1 Grate average temperature F Air quantity Q Heat quantity W Waste Wo Ash A1, A2, A3 Primary combustion air Qa Combustion point Qb Every other combustion completion point 31 Dry stoker 32 Combustion stoker 33 Post combustion stoker 34 Secondary combustion chamber 35 Waste heat boiler 36 Hopper 37 Dust supply device 38 Primary combustion air supply device 39 Ash discharge port 40 Exhaust gas purification device 41 Induction Fan 42 Chimney 43a / 43b Air preheater 44 Combustion amount calculation device 45 Target combustion amount setting device 46a / 46b Air amount calculation device 47 Combustion air amount adjustment device 48 Stoker speed adjustment device 49a Waste supply amount detector 49b Steam flow rate detector 50a -50c Waste layer level sensor 52 Combustion completion point detector 53 Burnout point detectors 54a-45d Damper 55 Automatic combustion control device

Claims (6)

In a stoker-type waste incinerator that performs combustion control using the grate temperature, measure the temperature at one or more locations for each grate in a plurality of grate locations throughout the stoker, and The air flow rate is calculated from the measured value of the combustion air amount, and based on the heat transfer cooling characteristics of the grate with respect to the relationship between the surface temperature of the grate upper wall surface, the grate air flow rate, and the grate passing heat amount, Calculate the amount of heat that passes through the grate from the average temperature and the amount of ventilation, and based on the relationship that the amount of heat that passes through the grate is directly proportional to the amount of heat generated by the dust , grasp the increase or decrease in the amount of heat generated by the combusted material based on the calculated value of the amount of heat passing through the grate A waste combustion state detection method using a grate temperature.
In a stoker-type waste incinerator that performs combustion control using the grate temperature, at least a grate tip part and a middle part of the grate upper wall surface for each grate for a plurality of grate parts in the whole stoker. with measuring the temperature of points, from said temperature difference of the temperature measured in the upper wall surface of each grate in the grate vicinity, or volatile combustion, or surface combustion, or a volatile combustion and surface combustion is generated at the same time A garbage combustion state detection method using a grate temperature characterized by grasping a combustion form of whether or not it is burning and detecting a progress state of waste combustion based on the grasped combustion form.   Use either one or both of the information related to the amount of heat generated by the combustion product ascertained by the method for detecting waste combustion state of claim 1 and the information related to the progress of waste combustion detected by the method for detecting waste combustion state of claim 2 And a waste combustion control method characterized by adjusting at least one of a waste supply speed, a stoker speed, a primary combustion air amount, and a primary combustion air distribution ratio. The refuse combustion control method according to claim 3 , wherein information relating to a boiler steam flow rate, a burnout point position, and a dust layer thickness is used together.   The flow rate of the grate is adjusted by using at least one of the calculation value of the grate temperature detected by the dust combustion state detection method of claim 1 or the calculated value of the heat amount passing through the grate or the calorific value of the combustion product. Grate temperature control method.   The flow rate of the grate is adjusted by using at least one of the information related to the grate temperature detected by the dust combustion state detection method of claim 2 or the grasped dust combustion form or the progress status of the waste combustion. Grate temperature control method to do.

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