TW202200933A - System for removing ash adhering to pipe groups of boiler - Google Patents

Abstract

A system (1) for removing ash adhering to pipe groups (2) of a boiler includes a soot blower (3) interposed between a plurality of the pipe groups (2); an induced blower (13) that induces exhaust gas at a downstream side of the pipe groups (2); and a controlling device (4) that controls the soot blower (3) and calculates a heat transmission coefficient of the boiler. When the heat transmission coefficient is equal to or more than a predetermined value, the controlling device (4) activates once the soot blower (3) after a predetermined interval. When the heat transmission coefficient is less than the predetermined value, the controlling device (4) carries out a process for determining adhering ash and continuously activates the soot blower (3) depending on the result of the process. Execution of the process for determining adhering ash involves at least one of the following four conditions of an amount of main steam of the pipe groups (2), a pressure difference of the exhaust gas, a rotation speed of the induced blower (13), and a total amount of combustion air to be supplied to a furnace.

Description

Boiler tube group adhering ash removal system

The present invention relates to a boiler tube group adhering ash removal system.

Incineration contained in the waste gas generated by the combustion of coal or garbage in a thermal power plant equipped with a coal-fired boiler, or in a facility such as a waste incinerator or a gasification melting furnace equipped with a waste heat boiler for power generation Ash tends to adhere and accumulate in the pipe group (the pipe group composed of the screen pipe of the boiler, the superheating pipe, the evaporating pipe, the water pipe of the economizer, etc.). Once the incineration ash accumulates in the pipe group, the pipe group may be corroded, and furthermore, the power generation efficiency will be deteriorated. Therefore, in general, a steam-type or shock-pulse-type sootblower is activated at a predetermined time interval (a certain period) to remove the ash accumulated in the pipe group (hereinafter referred to as "adhering ash"), that is, "adhering ash". Ash removal". However, when the amount of adhering ash deposited on the pipe group is small, even if the sootblower is activated, the amount of adhering ash that is removed is small, and therefore is less than the amount of electricity, steam, or gas consumed or utilized by the sootblower. In terms of cost, the effect of removing adhering ash is small. On the other hand, when the amount of adhered ash accumulated in the pipe group is large, if the sootblower is activated at regular intervals as described above, the adhered ash cannot be sufficiently removed, and the adhered ash may not be removed and remain in the pipe group. It is cured before the next soot blower is started, and it is difficult to remove the attached ash by the soot blower. In view of this, in order to appropriately remove the adhering ash from the tube group using a sootblower, various types of boiler tube group adhering ash removal systems have been developed.

For example, Patent Document 1 discloses a system in which the above-mentioned period is changed according to the degree of contamination of the pipe group, that is, the degree of accumulation of dust adhering to the pipe group. In addition, Patent Document 2 discloses a system for activating the sootblower taking into account conditions other than the degree of contamination of the pipe group. In addition, Patent Document 3 discloses a system in which the upstream and downstream pressures of the exhaust gas flowing through the pipe group are respectively measured, and the sootblower is activated when the difference between the pressures becomes a predetermined value or more.

In addition, the steam type has been mainly used for the sootblower, but in recent years, a shock pulse wave type which does not use steam has been developed and put on the market. The steam-type sootblower, once activated, continues to inject steam only for a predetermined time, and stops the injection of steam when the predetermined time elapses. On the other hand, a shock pulse wave sootblower, also known as a pressure wave or shock wave sootblower, or a shock pulse generator (SPG: Shock Pulse Generator), fills the interior of the sootblower once activated. The flammable gas will explode, emitting shock pulses (also known as "shock waves" or "pressure waves"). In addition, if the shock pulse type sootblower is activated once, the gas must be refilled for the next activation. This filling generally takes about 1 minute to 10 minutes. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Laid-Open No. 62-210316 [Patent Document 2] Japanese Patent Laid-Open No. 63-286609 [Patent Document 3] Japanese Patent Laid-Open No. 2017-181007

[Problems to be Solved by Invention]

In the techniques disclosed in Patent Documents 1 to 3, the sootblower is activated only once after the predetermined conditions such as the above-mentioned cycle are established. However, as described above, depending on the amount of deposited ash, it is not always possible to sufficiently remove the deposited ash if the sootblower is activated only once. Therefore, when the adhered soot cannot be effectively removed even if the sootblower is activated, according to the techniques disclosed in Patent Documents 1 to 3, it is necessary to wait for the arrival of the next cycle and other predetermined conditions after the sootblower is re-established. Start again. Therefore, according to these techniques, when the single sootblower start-up cannot sufficiently remove the attached ash, the heat exchange performance of the boiler cannot be restored at an early stage. In view of this, it is conceivable that when the sootblower is activated, it is not only activated once but multiple times continuously. However, there are cases in which the attached ash can be sufficiently removed by activating the sootblower once, but it is not economical to activate the sootblower several times when the above-mentioned prescribed conditions are satisfied.

In view of this, an object of the present invention is to provide a boiler tube group adhering ash removal system that can efficiently remove adhering ash at an early stage while maintaining economical efficiency. [Technical means to solve problems]

The boiler tube group adhering ash removal system of the present invention is a boiler tube group adhering ash removing system for removing adhering ash from a plurality of tube groups of a boiler for heat recovery from exhaust gas generated in a boiler, and is characterized by having: a soot blower is arranged between the plurality of pipe groups; an induced draft fan is arranged downstream of the plurality of pipe groups to induce the exhaust gas; and a control device controls the activation of the soot blower. The control device calculates the heat transfer coefficient of the boiler, and when the calculated heat transfer coefficient is greater than or equal to a predetermined value, one start-up is performed, that is, the sootblower is started only once at a predetermined period, and the Then, after the predetermined period or a period different from it, when the calculated heat transfer coefficient is less than the predetermined value, execute the alternative judgment of the first judgment and the second judgment. Processing, when the first judgment is obtained by the above-mentioned adhering ash determination processing, continuous activation is performed, that is, the above-mentioned sootblower is continuously activated a plurality of times without separating the above-mentioned predetermined period. In the case of the aforementioned second determination, the aforementioned first activation is performed. The deposition ash determination process includes a first condition that the main steam amount of the plurality of pipe groups is equal to or greater than a first threshold value, and a second condition that the pressure difference of the exhaust gas between the inlet and the outlet of the plurality of pipe groups is equal to or greater than a second threshold value. At least one of the second condition, the third condition that the number of revolutions of the induced draft fan is equal to or higher than the third threshold value, and the fourth condition that the total amount of combustion air supplied to the furnace is equal to or greater than the fourth threshold value, is executed. In the case where the adhering dust determination process is performed based on only one of the four conditions, the first determination is obtained when the one condition is satisfied, the second determination is obtained when the one condition is not satisfied, and the When the adhering dust determination process is executed based on 2, 3, or 4 of the above-mentioned 4 conditions, the above-mentioned first condition is obtained when all of the above-mentioned 2, 3, or 4 conditions are satisfied. It is judged that the second judgment is obtained when any one of the above-mentioned two, three, or four conditions is not satisfied. [Effect of invention]

According to the boiler tube group adhering ash removal system of the present invention, one-time start-up and continuous start-up are differentiated based on the heat transfer coefficient. In addition, when the heat transfer coefficient is less than the predetermined value, the adhering ash determination process can be executed to appropriately determine whether to continuously activate the sootblower, so that the adhering ash can be removed early and appropriately while maintaining economical efficiency.

Hereinafter, a description will be given of a boiler tube group adhering ash removal system as an embodiment and a modification with reference to the drawings. The configurations and the like shown below are only examples, and are not intended to exclude the application of various modifications or techniques not expressly shown. The configurations and the like shown below can be implemented without various modifications without departing from their gist. In addition, trade-offs can be made as necessary, or an appropriate combination can be made.

[1. Outline of Boiler Tube Group Adhesion Ash Removal System] Fig. 1 is a schematic configuration diagram of a boiler tube group adhering ash removal system 1 (hereinafter referred to as "removal system 1") according to the present embodiment. In addition, Fig. 1 also serves as a diagram showing a first modification example (excluding the system 1') to be described later. In FIG. 1 and FIGS. 4 to 6 to be described later, the orthogonal coordinate system formed by the X axis and the Y axis is illustrated and described. The X axis is the horizontal direction, and the Y axis is the vertical direction. In addition, the arrow direction of the Y axis is a vertical direction and an upward direction.

In this embodiment, as an example, the removal system 1 applied to the facility of the refuse incinerator provided with the boiler for generating electric power is demonstrated. Of course, the boiler tube group adhering ash removal system of the present invention can also be applied to other equipments such as thermal power plants and gasification melting furnaces. Boilers are roughly classified into a two-drum type including a steam drum and a water drum, and a one-drum type including a steam drum, and the removal system 1 can use either type of boiler. In addition, although the illustration of a steam drum is abbreviate|omitted in FIG. 1, the example of the equipment of the garbage incinerator provided with the single-drum type boiler is shown.

A removal system 1 is a system for removing ash adhered to a plurality of tube groups 2 of a boiler for heat recovery from exhaust gas generated in a furnace, and includes sootblowers 3 arranged between the plurality of tube groups 2; and a plurality of The induced draft fan 13 for attracting exhaust gas downstream of the pipe group 2; and the control device 4 for controlling the activation of the sootblower 3.

As will be described in detail later, the control device 4 calculates the heat transfer coefficient K of the boiler, and when the heat transfer coefficient K is greater than or equal to a predetermined value α1, "one start" is performed, that is, only one start is performed after a predetermined period. The soot blower 3 is again separated by this predetermined period or a period different from that. In addition, the control device 4 executes an alternative judgment of the adhesion of dust in one of the first judgment and the second judgment when the calculated heat transfer coefficient K is less than the predetermined value α1, and when the calculated heat transfer coefficient K is less than the predetermined value α2 Judgment processing. When the first determination is obtained in the adhering ash determination process, the control device 4 executes "continuous activation" in principle, that is, the sootblower 3 is continuously activated a plurality of times without a predetermined period of time. In the case of two judgments, "one start" is executed.

The adhering dust determination process is executed including at least one of the following first to fourth conditions. The first condition: the main steam volume Qs of the tube group 2 is equal to or greater than the first threshold value The second condition: the pressure difference ΔPg of the exhaust gas between the inlet and the outlet of the pipe group 2 is above the second threshold The third condition: the number of revolutions Qr of the induced draft fan 13 is equal to or greater than the third threshold Fourth condition: the total amount of combustion air supplied to the furnace Qc is equal to or greater than the fourth threshold For each of these four conditions, according to the inventor's experience, when each condition is satisfied, there is a high possibility that a large amount of adhering ash is deposited on the pipe group 2, so it is expected that the "continuous start-up" of the sootblower 3 is more effective. ideal conditions.

In FIG. 3, which will be described in detail later, as an example, only the above-mentioned four conditions (the first condition, the second condition, the third condition, and the fourth condition) are used for description, but these four conditions may be used according to design. Add other conditions (such as the fifth condition, the sixth condition, the seventh condition, the eighth condition, etc.). The other condition, for example, as the fifth condition, may be "the temperature of the main steam of the pipe group 2 is less than the fifth threshold value" measured by the outlet steam temperature measuring device 24b described later, and as the sixth condition, for example, may be "superheating" The amount of water sprayed by the descender 17 (described later) is less than the sixth threshold value. For example, as the seventh condition, it can be measured by the gas temperature measuring device 15b (outlet gas temperature measuring device) to be described later. "The outlet of the pipe group 2 The gas temperature of the exhaust gas is above the seventh threshold.” In addition, although not shown, in the equipment of the waste incinerator, it is possible to adopt the exhaust gas recirculation technology (Exhaust Gas Recirculation (EGR)) which circulates a part of the exhaust gas downstream of the dust removal device 11 to the vicinity of the stoker 7 . In this case, as the other condition, for example, as the eighth condition, a gas flow measuring device for measuring the gas flow rate of the circulating exhaust gas (circulating exhaust gas) may be provided separately from the gas flow measuring devices 16a and 16b described later. , and "the gas flow rate of the circulating exhaust gas is more than the eighth threshold value" measured by the gas flow rate measuring device is added. In addition, these other conditions, like the first to fourth conditions, are also divided into two based on the evaluation formula. Specifically, these other conditions, when the conditions of the evaluation formula are satisfied, there is a high possibility that a large amount of adhering ash accumulates in the pipe group 2, so it is ideal to perform "continuous start-up" of the sootblower 3. When the evaluation formula is When the condition is not satisfied, the so-called "continuous activation" of the sootblower 3 is not used (so it can be "one activation"). When the adhering dust determination process is executed based on only one of the four conditions of the above-mentioned first condition to the fourth condition, the first determination is obtained when the one condition is satisfied. On the other hand, when one of the conditions is not satisfied, a second judgment is obtained. In addition, when the adhering dust determination process is executed including 2, 3, or 4 of the above-mentioned 4 conditions (the above-mentioned fifth condition may also be added), the 2, 3, or 4 conditions are included. Or the first judgment will be obtained when all of the 4 conditions are met. On the other hand, when one of all the conditions including the 2, 3, or 4 conditions is not satisfied, a second judgment is obtained.

Hereinafter, other configurations other than the above-described configuration at least included in the system 1 will be described. Next, after the configuration is explained, the control regarding the activation of the sootblower 3 (including the adhering soot determination process) will be described in detail.

[2. System configuration] As shown in FIG. 1 , the removal system 1 includes a hopper 5 for storing incinerators such as garbage; and a feeder 6 for pushing out the incinerators stored in the hopper 5 from below the hopper 5 (in the Y-axis direction and below); and a stoker 7 for incineration while conveying the incinerated material pushed out by the feeder 6 ;

In addition, in the removal system 1, the heat of the exhaust gas including fly ash, which is generated by incinerating the incinerated objects in the grate 7, is disposed in each tube group 2 and an economizer 9 (the One, also known as "economizer") for heat exchange. Then, in the removal system 1, the dedusted is removed via a cooling tower 10 that cools the heat-exchanged exhaust gas, or a dedusting device 11 (eg, a bag filter) that dedusts the coal dust of the cooled exhaust gas. The exhaust gas is discharged from the chimney 12 to the atmosphere.

The path of the exhaust gas from the grate 7 to the opening of the chimney 12 is formed by a water wall, an air duct, or the like, and is substantially closed. Among the paths, the path extending from directly above the grate 7 toward the Y-axis direction and upward is called "air passage one" ("air passage" means "pass" in English), and the upper end of the air passage one is bent, The path adjacent to the airway 1 and extending in the Y-axis direction and downward is called "airway 2", and the path that is bent at the lower end of the airway 2, adjacent to the airway 2 and extending in the Y-axis direction and upward is called "airway 3" . The exhaust gas generated in the grate 7 flows as indicated by the arrows in Fig. 1 in a manner of rising in the first gas passage, descending in the second gas passage, and rising in the third gas passage. In addition, in order to induce the flow of the exhaust gas from the air passage to the chimney 12 , an induced draft fan 13 is arranged in the path between the dust removal device 11 and the chimney 12 .

The removal system 1 is provided with a pressure measuring device 14a (inlet pressure measuring device) arranged in the air passage 1 to measure the pressure of the exhaust gas; and a path of the exhaust gas arranged between the economizer 9 and the cooling tower 10 to measure the pressure of the exhaust gas pressure Measuring device 14b (outlet pressure measuring device).

In addition, the arrangement|positioning of each pressure measurement apparatus 14a, 14b is not limited to this. Depending on the design of the facility, as long as the inlet pressure measuring device 14a is arranged in the path of the exhaust gas, it is arranged at any place upstream of the most upstream tube group 2 among the plurality of tube groups 2 that are the objects of removal of the adhering ash, that is, "the plurality of tube groups 2". As long as the outlet pressure measuring device 14b is arranged in the path of the exhaust gas, it is arranged at any place downstream of the most downstream pipe group 2 among the plurality of pipe groups 2 that are the objects of removal of the adhering ash. , that is, "the exits of a plurality of pipe groups 2". However, these arbitrary locations are ideally located as close as possible to the plurality of pipe groups 2 to be removed as the adhering ash.

The removal system 1 is provided with a gas temperature measuring device 15a (inlet) which is arranged below the most upstream (lower) pipe group 21 among the plurality of pipe groups 2 arranged in the air passage 3 as objects for removal of adhering ash, and measures the temperature of the exhaust gas. A gas temperature measuring device); and a gas for measuring the temperature of the exhaust gas located in the path of the exhaust gas between the tube group 22c that is the most downstream (upper) of the plurality of tube groups 2 and the economizer 9 arranged in the gas passage 3 Temperature measuring device 15b (outlet gas temperature measuring device).

In addition, the arrangement|positioning of each gas temperature measuring apparatus 15a, 15b is not limited to this. Depending on the design of the facility, as long as the inlet gas temperature measuring device 15a is arranged in the path of the exhaust gas, it is arranged at any place upstream of the most upstream tube group 2 among the plurality of tube groups 2 that are the objects of the adhering ash removal, that is, " The inlet of the plurality of tube groups 2 is sufficient. The outlet gas temperature measuring device 15b may be arranged in the path of the exhaust gas. Among the plurality of tube groups 2 targeted for removal of the adhering ash, the outlet gas temperature measuring device 15b is arranged downstream of the most downstream tube group 2. Any place, that is, "the exits of the plurality of pipe groups 2" can be used. However, these arbitrary locations are ideally located as close as possible to the plurality of pipe groups 2 to be removed as the adhering ash.

In other words, in the present embodiment and the modified examples to be described later, the "plurality of pipe groups 2" that are the objects to remove the adhering ash means that they are arranged between the two pressure measuring devices 14a and 14b, and are arranged between the two gas temperature measurement devices. Tube group between devices 15a, 15b. In FIG. 1 , as an example, a configuration in which a plurality of tube groups 2 are arranged in the airway 3 is illustrated. The economizer 9 also includes a pipe group (see FIG. 6 ), but in the configuration of FIG. 1 , the economizer 9 is disposed downstream of the outlets of the plurality of pipe groups 2 , that is, further than the outlet gas temperature measuring device 15 b Since it is downstream, in this embodiment, the pipe group with which the economizer 9 is equipped is not considered as the pipe group which is the object of the adhering ash removal. In addition, although it mentions later, the pipe group with which the economizer 9 is provided is also considered as an example of "a plurality of pipe groups 2", which is a fourth modification of the present embodiment.

In the air passage 3, a pipe group 2 composed of a suspension pipe (screen pipe) 21 is arranged at the most upstream (the bottom in the Y-axis direction) of the flow direction of the exhaust gas. From the pipe group 21 toward the downstream (upward in the Y-axis direction), The tube group 2 constituted by each of the superheating tubes (superheaters) 22a, 22b, and 22c is arranged in sequence.

In FIG. 1, as an example, the structure in which the soot blower 3 (3a) is arrange|positioned among the several pipe groups 2 of the same type is shown. That is, the pipe group 2 formed by the superheating pipe 22a located most upstream among the pipe group formed by the superheating pipes, and the pipe group 2 arranged downstream of the pipe group 2 and adjacent to the pipe group 2 (consisting of the superheating pipe Between the pipe groups 2) formed by 22b, a soot blower 3a is arranged. In addition, the arrangement of the sootblowers 3 ( 3a ) is not limited to this, and can also be used in a pipe group composed of different types of pipe groups 2, such as boiler screen pipes, superheating pipes, evaporating pipes, and economizer water pipes, etc. Among them, the sootblowers 3 are arranged between adjacently arranged tube groups of different types. The sootblower 3 can be either a steam type or a shock pulse type, but here it is described as a shock pulse type sootblower.

The removal system 1 includes at least a gas flow measuring device 16a arranged in the second air passage to measure the flow rate of the exhaust gas, and a gas flow measuring device 16b arranged in the path of the exhaust gas between the dust removal device 11 and the induced draft fan 13 to measure the flow rate of the exhaust gas. one side. As described above, since the path of the exhaust gas from the grate 7 to the opening of the chimney 12 is substantially closed, the gas of the exhaust gas necessary for the calculation of the heat transfer coefficient K, which will be described later, can be obtained by installing one gas flow measurement device. traffic information.

In addition, the arrangement|positioning of each gas flow measurement apparatus 16a, 16b is not limited to this. It is sufficient to provide at least one in the path of the exhaust gas. From the viewpoint of reducing the cleaning frequency of the gas flow measurement device, it is desirable to arrange the gas flow measurement device downstream of the dust removal device 11 . That is, when one of the gas flow measurement devices 16a and 16b is selected, it is desirable to install the gas flow measurement device 16b. In addition, instead of providing the gas flow measuring device 16a, the gas flow rate of the exhaust gas in the air passage 2 may be calculated by calculation, and it may be used for calculation of the heat transfer coefficient K described later.

The removal system 1 is provided with a superheated desuperheater (desuperheater) 17 that sprays water inside the superheated tubes in order to appropriately cool the steam passing through the inside of the tube group 2 composed of the superheated tubes. In FIG. 1 , among the four pipe groups 2 arranged in the air passage 3, the superheat return descender 17 is arranged in the pipe group 2 constituted by the superheat pipe 22c arranged at the most downstream. The amount of water sprayed by the superheater 17 is measured by the spray water amount measuring device 18 .

The removal system 1 is provided with a steam temperature measuring device 24a (inlet steam temperature measurement device 24a) which is arranged inside the superheating pipe 22a located at the most upstream position among the superheating pipes included in the plurality of pipe groups 2 to be removed as the object of the adhering ash removal, and measures the temperature of the steam. device); and a steam temperature measuring device 24b (outlet steam temperature measuring device) which is arranged inside the superheating pipe 22c located at the most downstream and measures the temperature of the steam. The steam temperature measuring devices 24a and 24b are installed in the superheating pipes among the plurality of pipe groups 2 .

The removal system 1 includes a main steam amount measuring device 25 for measuring the amount of main steam flowing through the inside of the heat pipe. Here, the main steam amount measuring device 25 is arranged inside the superheating pipe 22 a located at the most upstream position among the superheating pipes included in the plurality of pipe groups 2 . The removal system 1 is provided with a primary air supply device 26 located below the grate 7; a secondary air supply device 27 located in an air passage above the grate 7; The combustion air amount measuring device 28 for the total amount of primary air and secondary air (total combustion air) of the route.

By each pressure measuring device 14a, 14b, each gas temperature measuring device 15a, 15b, gas flow measuring device 16a, 16b, spray water amount measuring device 18, each steam temperature measuring device 24a, 24b, main steam amount measuring device 25, combustion Various information measured by the air volume measuring device 28 is input to the control device 4 . The control device 4 is equipped with a processor or a timer operated by a clock, and a memory device (all omitted from illustration) in order to exclude the electronic control device (computer) included in the system 1 .

[3. Control structure (flow chart)] As described above, the control device 4 calculates the heat transfer coefficient K of the boiler, and according to the heat transfer coefficient K, appropriately executes the adhering soot determination process, and simultaneously causes the sootblower 3 to perform "one start" or "continuous start". 2 and FIG. 3 (a) to (d) shown in the flow chart, the control of the start of the soot blower 3 (including the adhering ash determination process) will be described in detail. Here, the dust removal device 11 will be described as a bag filter.

First, the operator operates a start switch, a control panel, etc. (not shown) to start the operation of equipment such as an incinerator, and the removal system 1 is also activated. Executed by the control device 4 . In addition, the times t1, Tmin, Tmax, and the initial value of Δt appearing in this flowchart, the initial value of the dirty heat transfer coefficient Kd, the initial value of the flag F, the predetermined values α1, α2, and the recovery threshold value R is set as follows, and stored in the memory device before the "start" of this flowchart. The clean heat transfer coefficient Kc is the initial value except that the heat transfer coefficient calculated for the first time when the system 1 is activated, so it is not necessary to set it before the "start" of this flowchart.

The time t1 is the first time (the remaining time of the timer) when the timer is counted down, and corresponds to the period when the sootblower 3 is "started once". The initial value of the time t1 is a predetermined value satisfying the relationship of “0<Tmin<t1≦Tmax”. Tmin is the minimum value (shortest period) of the period in which the sootblower 3 is activated, and is set to, for example, 1 hour. In addition, Tmax is the maximum value (the longest period) of the period in which the sootblower 3 is activated, and is set to 3 hours, for example. The initial value of the time t1 is set to, for example, the time obtained by "2/3×Tmax-Δt (for example, Δt is 0.5 hours)". In addition, for simplicity of description, the values of Tmin and Tmax are set to be integer multiples of Δt, respectively. In addition, the time t1 is changed from the initial value by steps S7 and S19 to be described later.

The contamination heat transfer coefficient Kd is the heat transfer coefficient in the case where the adhered ash is expected to be deposited on the pipe group 2 and the like to be removed as the object of the adhered ash removal and become contaminated. The initial value of the contamination heat transfer coefficient Kd is set to a predetermined value (for example, Kd=0.5) satisfying the relationship of "0<Kd<α2". In addition, the contamination heat transfer coefficient Kd is changed from the initial value by step S3 described later. The initial value of the flag F is set to F=0 (first value). In addition, the flag F is subsequently changed to F=0 (first value), F=1 (second value), and F=2 (third value) by steps S9, S20, and S14 to be described later. one of them.

The first predetermined value α1 and the second predetermined value α2 are compared with the heat transfer coefficient K (clean heat transfer coefficient Kc) in each of the steps S5 and S15 described later, respectively, to determine whether the sootblower 3 is set to " 1 start" judgment threshold. In addition, the second predetermined value α2 is compared with the heat transfer coefficient K (clean heat transfer coefficient Kc) in step S15 described later, and is also a threshold value for determining whether or not to execute the adhering dust determination process. It satisfies the relationship of "0<α2<α1". Here, in order to simplify the description, it is assumed that the relationship of "0<α2<1<α1" is satisfied, and the description will be continued. In addition, the clean heat transfer coefficient Kc is the heat transfer coefficient calculated immediately after the sootblower 3 is started. In other words, the clean heat transfer coefficient Kc is the heat transfer coefficient in the state where the heat exchange rate is improved, because the soot attached to the tube group 2 has been removed to a certain extent immediately after the sootblower 3 is started. The first predetermined value α1 is set to be a value at which the heat exchange of the tube group 2 is remarkably good when the clean heat transfer coefficient Kc is equal to or higher than α1, and there is no accumulation of adhering ash or the accumulation of adhering ash is positive. Here, for the sake of simplicity of description, the first predetermined value α1 is set so that after the flag F is changed to F=2 in step S20 to be described later, soot blowing is performed only by "one start" of the soot blower. A single start-up of the blower does not make the clean heat transfer coefficient Kc more than α1, and it must be set to "continuous start" and at least 2 consecutive starts of the sootblower 3 can be achieved. For example, the first predetermined value α1 is set to α1=1.2 (W/m ² K). In addition, if the second predetermined value α2 is set to a clean heat transfer coefficient Kc of α2 or more and less than α1, the heat exchange of the tube group 2 is not remarkably good, but the accumulation of adhering ash does not affect the operation of the equipment. Since it has a large influence, it can be said that it is sufficient to perform "one start-up" of the sootblower. In other words, it is set to a value that requires the adhering dust determination process described later if the clean heat transfer coefficient Kc is less than α2. The second predetermined value α2, here, for the sake of simplicity of description, is also set to blow the soot blower 3 only after “one start” of the sootblower 3 immediately after the flag F is changed to F=2 in step S20 described later. A single activation of the soot blower does not make the clean heat transfer coefficient Kc more than α2, and it is necessary to set it as "continuous activation" and to do at least 2 consecutive activations of the sootblower 3 to achieve the value. For example, the second predetermined value α2 is set to α2=0.8 (W/m ² K). Therefore, in the flowchart of FIG. 2 described later, when the flag F is temporarily changed to F=2 in step S20 described later, as long as it does not become the second judgment in the later-described adhering dust judgment processing, in principle The control device 4 and the sootblower 3 perform at least 2 consecutive "continuous starts". Here, for simplicity of description, the values of α1 and α2 are set as described above so as to satisfy the relationship of "0<α2<1<α1", but as long as the relationship of "0<α2<α1" is satisfied, the values of α1 and α2 can also be set according to The values of α1 and α2 are appropriately set according to the design. In this case, immediately after the flag F is changed to F=2 in step S20 described later, the soot blower 3 will in principle perform "continuous startup", but it is not limited to "continuous startup", and may also be "continuous startup". 1 start". The recovery threshold R is compared with the recovery rate (Kc/Kd), and is a threshold for judging the effect of removing adhering ash (the degree of improvement of the heat transfer coefficient K), and its initial value is set to satisfy the relationship of "1≦R" The specified value (eg R=1). Here, the recovery rate is a variable indicating how much the heat transfer coefficient K is recovered (improved) before and after the sootblower 3 is activated, and is a value obtained by dividing the clean heat transfer coefficient Kc by the dirty heat transfer coefficient Kd. In addition, each of the first predetermined value α1 , the second predetermined value α2 , and the recovery threshold value R is a constant value, that is, it is not changed from the respective initial values appropriately set according to the design. In addition, each of the aforementioned Tmin, Tmax, and Δt is also a constant, that is, it is not changed from the respective initial values appropriately set according to the design.

In step S1, the control device 4 determines whether or not a predetermined time has elapsed after the operation of the facility (for example, an incinerator) has been started. This is because the environmental conditions (for example, temperature, pressure, etc.) in the equipment are not stable until a predetermined time elapses after the operation of the equipment is started. The control device 4 repeatedly executes the process of step S1 from the start of the operation of the equipment until the predetermined time elapses, and executes the process of step S2 when the predetermined time elapses.

惟，各變數如下所述。 Q：交換熱量[W]{=(Tg_out -Tg_in )×Cp_g ×W_g } A：熱傳遞面積[m² ] LMTD：對數平均溫度差[K][=(dT₁ -dT₂ )/{ln(dT₁ /dT₂ )}] Tg_in ：過熱器入口氣體溫度[K] Tg_out ：過熱器出口氣體溫度[K] Ts_in ：過熱器入口蒸氣溫度[K] Ts_out ：過熱器出口蒸氣溫度[K] dT₁ ：Tg_in -Ts_out dT₂ ：Tg_out -Ts_in CP_g ：氣體比熱[J/kgK] W_g ：氣體流量[kg/s]The control device 4, in step S2, calculates the heat transfer coefficient K based on the temperature information and the flow rate information. Then, after the heat transfer coefficient K is calculated, the control device 4 executes the process of step S3. The heat transfer coefficient K is represented by the following (Formula 1).

However, the variables are as follows. Q: Heat exchange [W]{=(Tg _out -Tg _in )×Cp _g ×W _g } A: Heat transfer area [m ² ] LMTD: Logarithmic mean temperature difference [K][=(dT ₁ -dT ₂ ) /{ln(dT ₁ /dT ₂ )}] Tg _in : Superheater inlet gas temperature [K] Tg _out : Superheater outlet gas temperature [K] Ts _in : Superheater inlet steam temperature [K] Ts _out : Superheater Outlet steam temperature [K] dT ₁ : Tg _in -Ts _out dT ₂ : Tg _out -Ts _in CP _g : Gas specific heat [J/kgK] W _g : Gas flow rate [kg/s]

The temperature information and the flow rate information are measured and sent to the control device 4 as follows. That is, the superheater inlet gas temperature _Tgin is measured by the inlet gas temperature measuring device 15a, and the superheater outlet gas temperature Tg _out is measured by the outlet gas temperature measuring device 15b. The superheater inlet steam temperature Ts _in is measured by the inlet steam temperature measuring device 24a, and the superheater outlet steam temperature Ts _out is measured by the outlet steam temperature measuring device 24b. Further, the gas flow rate _Wg is measured by one of the gas flow rate measuring devices 16a and 16b, or obtained by calculation. In addition, the gas specific heat Cp _g is the specific heat of the exhaust gas, and is a constant corresponding to the composition of the exhaust gas. In addition, the heat transfer area A is the sum of the heat transfer areas of the superheaters in the plurality of tube groups 2 .

The control device 4, in step S3, stores the heat transfer coefficient K calculated in step S2 in the memory device (not shown) according to the value of the flag F at the time point of the processing in step S3 as the clean heat transfer coefficient One of Kc or the contamination heat transfer coefficient Kd. Specifically, the control device 4 sets Kc=K when the flag F is the first value, where F=0, and when the flag F is the second value, where F=1 In this case, Kd=K is set, and when the flag F is the third value, here is the case of F=2, Kd=K is set, and the memory is stored in the memory device. After the flow chart starts, the flag F is the initial value, that is, F=0, so the control device 4 sets the heat transfer coefficient K just calculated as the clean heat transfer coefficient Kc and stores it in the memory device (ie, Kc=K ). Then, the control device 4 executes the process of step S4.

The control device 4 determines whether the flag F is F=0 in step S4. When the flag F is F=0, that is, immediately after the “start” of this flowchart, or immediately after the sootblower 3 in step S13 described later is started, the control device 4 executes the step Processing of S5. In the case where the flag F is not F=0 (in the case of F=1, F=2), the processing flow proceeds toward the activation of the sootblower 3 in step S13 described later, so the control device 4 executes the processing in step S10 .

The control device 4 determines in step S5 whether or not the value of the clean heat transfer coefficient Kc stored in the memory device is equal to or greater than the first predetermined value α1. When the value of the clean heat transfer coefficient Kc is greater than or equal to the first predetermined value α1, it is expected that the heat exchange of the tube group 2 is remarkably good, and there is little or no accumulation of adhering ash. Therefore, the control device 4 performs the process of step S6 because the process flow is directed toward the process of extending the period of activation of the sootblower 3 . When the value of the clean heat transfer coefficient Kc is less than α1, the heat exchange of the tube group 2 is not necessarily good, so the control device 4 executes the process of step S15.

In step S6, the control device 4 determines whether or not the time t1 is less than the longest period, that is, Tmax. When the value of the time t1 is less than Tmax (here, 3 hours), the control device 4 increases the value of the time t1 (extracts the time t1 ) to change it, and thus executes the process of step S7 . When the value of time t1 is Tmax, since time t1 cannot be increased and changed, the control device 4 executes the process of step S8 without changing the value of time t1 (step S7 is skipped).

The control device 4 changes the value of the time t1 to the value of "t1+Δt" in step S7. In other words, the control device 4 sets t1=t1+Δt, changes the value of t1 in the above-mentioned memory device, and stores it in the memory device. That is, the control device 4 resets the period to be longer than the previously set value. This is because when the clean heat transfer coefficient Kc is equal to or greater than the first predetermined value α1, if the sootblower 3 is activated excessively at the current time point, it is not ideal from the viewpoint of cost-effectiveness. "One start" of the sootblower 3 is performed for a longer period than before. Then, the control device 4 executes the process of step S8.

The control device 4 starts a timer (counter) in step S8. The started timer counts down from the time t1 toward 0 based on the clock provided in the control device 4 . For example, when the time t1 at the time of turning on is 2 hours, 2 hours (7200 seconds) are counted, and the timer is stopped when the count value becomes 0. After the timer stops, the control device 4 executes the process of step S9.

The control device 4, in step S9, changes the value of the flag F stored in the above-mentioned memory device to F=1, and then stores it in the memory device. Then, the control device 4 returns the processing flow to step S2, and executes the processing of step S2 again. Since the processing of step S2, step S3, and step S4 has already been described, the processing from step S4 to the processing of step S10, which is the next step, will be briefly described below. That is, the control device 4 calculates the heat transfer coefficient K after a period of time has elapsed by the timer (step S2), and in the next step S3, the flag F is F=1, so the previously calculated heat transfer coefficient is K is set as the pollution heat transfer coefficient Kd and is stored in the above-mentioned memory device (ie, Kd=K). Then, since the flag F at the current time point is F=1, the control device 4 determines that the flag F is not F=0 in step S4, and executes the process of step S10 as the next process.

The control device 4, in step S10, determines whether the dust removal device 11, that is, the bag filter is being backwashed. Since the control device 4 controls the execution of "backwashing" of the bag filter, it can be determined whether or not the bag filter is being backwashed. The control device 4 repeatedly executes the process of step S10 when it is determined that the bag filter is being backwashed, and executes the process of step S11 when it is determined that the bag filter is not being backwashed. Thereby, the control device 4 does not activate the sootblower 3 while the backwash of the bag filter is being performed, and can wait for the end of the backwash before activating the sootblower 3 .

In addition, when it is determined that the bag filter is being backwashed, the reason why the control device 4 repeats the process of step S10 is as follows. Backwashing of the bag filter is usually performed by stopping the flow of exhaust gas. Therefore, if the shock pulse type sootblower 3 is activated during backwashing of the bag filter, the pressure inside the air duct of the flue, which circulates the exhaust gas, will increase significantly, and the equipment may fail. However, in the removal system 1, the control device 4 does not activate the sootblower 3 during backwashing of the bag filter, but waits for the backwashing to end before starting the sootblower 3, so the above-mentioned failure can be prevented. Here, since the sootblower 3 is described as being of the shock pulse type, step S10 is provided, but when the sootblower 3 is of the steam type, step S10 can be omitted. Therefore, in this case, the next step of step S4 becomes step S11.

The control device 4, in step S11, determines whether the value of the flag F stored in the storage device is F=1. When the flag F is F=1, the control device 4 executes the process of step S12. In addition, when the flag F is not in the case of F=1, that is, in the case of F=2, the control device 4 executes the process of step S13. Here, since the current time-point flag F is F=1, the control device 4 executes the process of step S12. The control device 4, in step S12, restores the count value of the timer, that is, resets it to time t1. Next, the control apparatus 4 performs the process of step S13. The control device 4, in step 13, starts the sootblower 3 only once. Then, the control device 4 executes the process of step S14. In addition, in step S11, when the flag F is not F=1, that is, in the case of F=2, the control device 4 skips step S12 and executes the process of step S13, so the count value of the timer does not change. will be reset. In the case of F=2, the control device 4 will in principle execute the "continuous start-up" of the sootblower 3 until the clean heat transfer coefficient Kc becomes equal to or greater than the second predetermined value α2, and this is because at this time an additional saving of 1 A process to continuously activate the sootblower 3 at a higher speed.

The control device 4, in step S14, changes the value of the flag F stored in the above-mentioned memory device to F=0, and then stores it in the memory device. This is because the heat transfer coefficient K calculated in the process of the next step S2 is the value immediately after the sootblower 3 is started, so this value is stored in the above-mentioned memory device in the process of the next step S3 as the clean heat transfer Coefficient Kc. Then, the control device 4 returns the processing flow to step S2, and executes the processing of step S2. The processes of step S2, step S3, step S4, and step S5 have already been described, so the description is omitted.

Next, the case where the control device 4 executes the process of step S15 as the next step of step S5 (when the value of the clean heat transfer coefficient Kc in step S5 is less than α1) will be described. The control device 4, in step S15, determines whether or not the value of the clean heat transfer coefficient Kc stored in the storage device is less than the second predetermined value α2. When the value of the clean heat transfer coefficient Kc is not less than the second predetermined value α2, that is, α2≦Kc<α1, it is expected that although the heat conduction of the tube group 2 is not remarkably good, the accumulation of adhering ash will not affect the The operation of the equipment has a great influence. Therefore, in order to perform the processing flow of starting the sootblower 3 at intervals, the control device 4 executes the processing of the aforementioned step S8. When the value of the clean heat transfer coefficient Kc is less than the second predetermined value α2, in order to determine whether the value of the clean heat transfer coefficient Kc is lowered due to the adhesion of dust, the control device 4 executes the process of step S16, that is, Adhesion ash judgment processing.

The control device 4 executes adhering dust determination processing in step S16. An example of a specific process in the adhering dust determination process will be described later using FIG. 3 . The deposition ash determination processing is to selectively determine "the amount of attached ash accumulated in the plurality of tube groups 2 is large, and the heat exchange between the exhaust gas and the boiler is not sufficiently performed" (first determination), or "the amount of attached ash is determined". It is a process where the calculated heat transfer coefficient Kc is less than the second predetermined value α2 due to the operating environment and operating conditions of the equipment" (second judgment). When the first determination is obtained by the adhering soot determination process, the control device 4 executes the process of step S17 in order to continuously activate the sootblower 3 according to the recovery rate (Kc/Kd). When the second determination is obtained by the adhering dust determination process, the control device 4 executes the process of step S21 in order to confirm the state of the device or determine whether the device needs to be stopped.

The control device 4, in step S17, calculates the recovery rate (Kc/Kd) from the clean heat transfer coefficient Kc and the dirty heat transfer coefficient Kd memorized in the memory device, and determines whether the recovery rate is the recovery rate stored in the memory device. above the threshold R. When the recovery rate is less than the recovery threshold R, the possibility of improvement of the heat transfer coefficient K of the sootblower 3 is low even if the sootblower 3 is activated more often, so the control device 4 executes the process of step S21. When the recovery rate is greater than or equal to the recovery threshold R, the effect of removing the adhering ash by the activation of the sootblower 3 can be expected. Therefore, in order to remove the adhering ash at an early stage, the processing flow is directed to the "continuous activation" of the sootblower 3. Since the process proceeds, the control device 4 executes the process of step S18.

In step S18, the control device 4 determines whether or not the time t1 is larger than Tmin, which is the shortest period. When the time t1 is longer than Tmin, the control device 4 executes the process of step S19 in order to shorten the period when the sootblower 3 is "started once". This is because the adhering ash cannot be effectively removed during the initial "one-time startup" due to the properties of the ash. Therefore, it is considered that the first determination is obtained by the adhering ash determination processing. After the "continuous startup" is completed, when the control device 4. When the sootblower 3 is "activated once", the "primary activation" of the sootblower 3 is performed in a shorter period than before (in other words, earlier than before). The control device 4 changes the value of the time t1 to the value of "t1-Δt" in step S19. In other words, the control device 4 sets t1=t1-Δt, changes the value of t1 in the above-mentioned memory device, and stores it in the memory device. Then, the control device 4 executes the process of step S20. When the time t1 is Tmin, since the time t1 cannot be changed any further, the control device 4 executes the process of the step S20 without changing the value of the time t1 (step S19 is skipped).

The control device 4, in step S20, changes the value of the flag F stored in the above-mentioned memory device to F=2, and then stores it in the memory device. Then, the control device 4 returns the processing flow to step S2, and executes the processing of step S2. Since the processing of step S2, step S3, and step S4 has already been described, the processing from step S4 to the processing of step S10, which is the next step, will be briefly described below. That is, the control device 4 calculates the heat transfer coefficient K when the recovery rate is equal to or greater than the recovery threshold R (step S2), and in the next step S3, the flag F is F=2, so the previously calculated heat transfer coefficient is K is set as the pollution heat transfer coefficient Kd and is stored in the above-mentioned memory device (ie, Kd=K). Then, in the next step S4, the flag F at the current time point is F=2, so the control device 4 determines that the flag F is not F=0, and executes the next step S10. Then, in step S10, when the control device 4 determines that the bag filter is not being backwashed, the process of step S11 is executed. In step S11, the current time-point flag F is F=2, so the control device 4 skips step S12 and executes the process of step S13. That is, when the flag F is F=2, the timer will not be reset, and the control device 4 will execute the process of step S13 in order to start the sootblower 3 immediately.

After the sootblower 3 is activated in step S13, as described above, the control device 4 changes the flag F to F=0 in step S14, and returns the processing flow to step S2 again. Here, in the next processing flow, the control device 4 executes Step S2, Step S3, Step S4, Step S5, Step S15, Step S16, Step S17, Step S18, Step S19 (skip as appropriate), When the process is performed in step S20, the control device 4 performs the process in step S2, step S3, step S4, step S10, step S11, and step S13 thereafter. Therefore, in this case, the processing flow is to execute step S13 without starting the timer in step S8, and thus the sootblower 3 is "continuously activated".

Next, as an explanation of the flowchart of FIG. 2 , lastly, when the second judgment is obtained by the adhering dust judgment processing in step S16 , or when the recovery rate in step S17 is less than the recovery threshold R, the control device 4 will be described. Step S21 is executed. The control device 4 determines in step S21 whether or not an operation for checking the state of the equipment or stopping the operation of the equipment (for example, operation of a control panel) has been started by the operator or operator. Since the control device 4 controls the operation of various devices arranged in the facility, it can be determined whether or not the operation has been started. When the control device 4 determines that the job has not been started, the process of step S8 is executed. That is, in this case, even if the sootblower 3 is activated in step S17, it is found that the adhering ash removal cannot be performed effectively, and therefore "continuous activation" of the sootblower 3 is not performed from the viewpoint of cost-effectiveness, but In order to reduce the accumulation of more ash in the pipe group 2, the processing flow of "one start-up" of the sootblower 3 is performed. On the other hand, when the control device 4 determines that the operation has been started, it does not execute any of the processes in steps S1 to S20 after that, but separately executes the processing necessary for the operation. After that, the operation of the entire removal system 1 including the control device 4 is completed, that is, the operation of the facility is stopped.

According to this flowchart, when the "one-time start" of the sootblower 3 is separated by a timer, when the clean heat transfer coefficient Kc is equal to or greater than the first predetermined value α1, the period is set to be longer than the previous period. Further, when the clean heat transfer coefficient Kc is less than the first predetermined value α1, the period is not changed from the previous period, or the period is shortened from the previous period. Moreover, according to this flowchart, even in the case of "continuous activation" of the sootblower 3 without a timer interval, the calculation of the heat transfer coefficient K is performed every time the sootblower 3 is activated. Then, the control device 4 executes "continuous start-up" of the sootblower 3 until the value of the recovery rate R based on the calculated heat transfer coefficient K (clean heat transfer coefficient Kc, dirty heat transfer coefficient Kd) increases. The heat transfer coefficient Kc is equal to or greater than the second predetermined value α2. That is, the number of times of starting the sootblower 3 in the "continuous starting" is variable, and if the value of the recovery rate R has a large rising speed (the rising speed is fast), the number of times is automatically reduced. The value of is small (the rising speed is slow), the number of times is automatically increased. The control device 4 can store the value of the recovery rate calculated every time step S17 is executed and the time information of the time point of the calculation in the above-mentioned memory device in order, and the recovery rate calculated at the current time point can be used for the rising speed. It is calculated from the value of the value, the value of the most recent recovery rate, and the value of the difference between the two pieces of time information (time interval or time difference). Specifically, the control device 4 calculates the ascending speed by the expression [{(recovery rate calculated at the current time point)-(the latest recovery rate)}/(the time difference)]. If the refilling time of the gas of the shock pulse wave sootblower is set to be less than 3 minutes (3min), for example, the so-called rising speed is fast, for example, the number of "continuous starts" is 2 times (less than 6min) Or the case where the rising speed is 0.04 (/min) or more after 3 times (less than 9min), and the so-called slow rising speed is, for example, the rising speed is less than 0.04 (/ min) case.

Next, with regard to the details of the adhering dust determination process, that is, step S16 , the processing flow will be described with reference to FIGS. 3( a ) to 3 ( d ). Here, based on the experience of the inventors, only the above-mentioned four conditions are set as objects, and the following four conditions are distinguished to explain which of these conditions is used. However, as described above, in addition to the above-mentioned four conditions, other conditions may be added depending on the design. In addition, in the following description, as the next process of step S15 of FIG. 2, it is assumed that the control device 4 executes the process of step S161, and it demonstrates. Then, the description will be made in order from FIG. 3( a ). FIG. 3( a ) is a processing flow (situation 1) in which the adhering dust determination processing is executed based on all of the above-mentioned four conditions. In step S161, the control device 4 determines whether or not the main steam amount Qs measured by the main steam amount measuring device 25 is equal to or greater than the lower limit main steam amount qsmin (first threshold) that is allowable during the operation of the facility. When the main steam amount Qs is less than qsmin, the control device 4 considers that the "second determination" has been obtained, and then executes the process of step S21 in FIG. 2 . When the main steam amount Qs is equal to or greater than qsmin, the control device 4 executes the next step, which is the process of step S162 here.

The control device 4, in step S162, uses the pressure information measured by the pressure measuring devices 14a, 14b to calculate the pressure difference of the exhaust gas at the inlet and the outlet of the plurality of tube groups 2, that is, the gas differential pressure in the furnace ⊿Pg, It is determined whether or not the furnace gas differential pressure ⊿Pg is equal to or greater than the furnace gas differential pressure p gmin (second threshold value), which is the lower limit allowable during the operation of the facility. When the gas differential pressure ⊿Pg in the furnace is less than p gmin, the control device 4 considers that the "second judgment" has been obtained, and then executes the process of step S21 in FIG. 2 . When the gas differential pressure ⊿Pg in the furnace is greater than or equal to p gmin, the control device 4 executes the next step, which is the process of step S163 here.

In step S163, the control device 4 determines whether or not the number of revolutions Qr of the induced draft fan 13 is equal to or greater than the number of revolutions qrmin (third threshold) of the lower limit allowable during the operation of the equipment. When the number of revolutions Qr is less than qrmin, the control device 4 considers that the "second judgment" has been obtained, and then executes the process of step S21 in FIG. 2 . When the number of revolutions Qr is equal to or greater than qrmin, the control device 4 executes the next step, which is the process of step S164 here. In addition, since the control device 4 controls the number of revolutions Qr of the induced draft fan 13, the number of revolutions Qr is grasped.

In step S164, the control device 4 determines whether the total combustion air Qc measured by the combustion air amount measuring device 28 is equal to or greater than the lower limit total combustion air qcmin (fourth threshold) allowed during the operation of the equipment. When the total amount of combustion air Qc is less than q cmin, the control device 4 considers that the "second determination" has been obtained, and then executes the process of step S21 in FIG. 2 . When the total amount of combustion air Qc is equal to or greater than q cmin, the control device 4 executes the processing of the next step. Here, it is considered that the "first determination" is obtained, and the process of step S17 in the next FIG. 2 is executed. In addition, the order of the processing flow of the four processes of steps S161 to S164 is not limited to this, and may be reversed as appropriate.

The processing flow (situation 2) of FIG. 3(b) is a case where three judgment elements of steps S161 to S163 are executed among the four judgment elements included in the processing flow of FIG. 3(a). Fig. 3(b) is an example of a flowchart of the adhering dust determination process executed based on three of the above-mentioned four conditions. Any three of the four determination elements of steps S161 to S164 may be used, and the order of the process is: Either first.

The processing flow (situation 3) of FIG. 3( c ) is for executing two judgment elements of steps S161 and S162 among the four judgment elements included in the processing flow of FIG. 3( a ). Fig. 3(c) is an example of the processing flow of the adhering dust determination process based on two of the above-mentioned four conditions. Any two of the four determination elements of steps S161 to S164 may be used, and the order of determination is: Either first.

The processing flow (situation 4) of FIG. 3(d) is for executing only the judgment element of step S161 among the four judgment elements included in the processing flow of FIG. 3(a). FIG. 3( d ) is an example of a flowchart in which the adhering dust determination process is executed based on one of the above-mentioned four conditions, and any one of the four determination elements of steps S161 to S164 may be used. In addition, in the case of any one of the above-mentioned conditions 1 to 4, it is preferable that step S161 includes the information of the main steam quantity Qs not used in the calculation of the heat transfer coefficient K.

[4. Effect] As described above, in the removal system 1, the control device 4 distinguishes between "one start" and "continuous start" using the sootblower 3 based on the calculated heat transfer coefficient K, so that it is possible to perform early and appropriate operation while maintaining economical efficiency. Adhesive ash is removed.

The adhering ash determination process includes conditions based on the inventor's experience, that is, based on at least one of the main steam volume Qc, the gas differential pressure ⊿Pg in the furnace, the number of revolutions Qr of the induced draft fan 13, and the total amount of combustion air Qc Therefore, it is possible to appropriately determine the deposition state of the adhering ash on the pipe group 2 .

In the removal system 1, when the first judgment is obtained by the adhering ash judgment processing, the recovery rate is calculated from the dirty heat transfer coefficient Kd and the clean heat transfer coefficient Kc, and when the recovery rate is above the recovery threshold R, the soot will be blown. The device 3 is "continuously activated", whereby the attached dust can be removed early. In addition, except in the system 1, the control device 4 automatically reduces the number of activations of the sootblowers 3 in "continuous activation" when the rate of increase of the recovery rate is large, and when the rate of increase of the recovery rate is small , the number of times is automatically increased. Therefore, the control device 4 appropriately increases or decreases the number of activations of the sootblower 3 in the "continuous activation" control according to the condition of the attached ash, so that the deposition can be effectively removed compared to the case where the number of times is a fixed value. ash, and can also guarantee the economy.

According to the removal system 1, when the clean heat transfer coefficient Kc is greater than or equal to the first predetermined value α, the control device 4 judges that the heat conduction of the tube group 2 is extremely good (no or very little deposition of adhering ash), and performs "one start" It is possible to avoid excessive activation of the sootblower 3, and as a result, the economical efficiency can be further ensured. On the other hand, when the recovery rate is greater than or equal to the recovery threshold R, the period of the "one-time startup" that follows after the "continuous startup" ends is shortened and reset. Therefore, even if the properties of the ash are strong enough to adhere to, " The soot blower 3 is also "started once" in a short period of time, so that the adhering ash can be removed before the ash is thickly deposited on the pipe group 2. Therefore, it is not necessary to perform "continuous start-up" frequently, so the result can be more economical.

According to the removal system 1, the control device 4 does not activate the sootblower 3 while backwashing of the bag filter as the dust removal device 11 is being performed, and waits for the backwash to complete before activating the sootblower 3, thereby preventing equipment failure.

The sootblower 3 may be either a steam type or a shock pulse type. However, the steam-type sootblower uses the steam generated by the heat exchange between the exhaust gas and the boiler. Therefore, the amount of steam supplied from the boiler to the turbine to generate electricity is reduced, and as a result, the amount of electricity generated in the facility may be reduced. Therefore, when the power generation amount of the facility is important, it is desirable to arrange a shock pulse type sootblower that does not use steam.

The sootblower 3 is usually arranged on the wall surface of the air duct or the like that forms the path of the exhaust gas. Therefore, when the sootblower 3 in FIG. 1 is of the steam type, the direction in which the spray nozzle of the sootblower 3 expands and contracts is the direction on the plane including the X axis and orthogonal to the Y axis. Steam is sprayed in the Y-axis direction. On the other hand, when the sootblower 3 is of the shock pulse type, the emission direction of the shock pulse wave is a direction on a plane including the X axis and orthogonal to the Y axis. Therefore, in the case of the removal system 1 with the shock pulse wave sootblower 3, in FIG. 1, if the shock pulse wave is emitted toward the wall between the air passage three and the air passage two, the wall surface will vibrate, not only the pipe. The ash adhering to the group 2 can be removed even the ash adhering to the wall surface.

[5. Modifications] Hereinafter, a modification of the removal system 1 having a plurality of sootblowers 3 will be described. The first modification is an example in which the sootblowers indicated by the dotted line symbol 3' and the symbol 3" are used in Fig. 1. The second modification is shown in Figs. 4(a) to 4(c). An example of the case where the number of the tube groups 2 arranged in the three air passages in Fig. 1 is larger than that in Fig. 1. The third modification is an example in which the boiler structure of the facility is a tail-end type as shown in Fig. 5 . The fourth modification is an example in which the boiler structure of the facility is a double-drum boiler as shown in FIG. 6 . In the following description, the same elements as those of the removal system 1 of FIG. 1 described above are denoted by the same reference numerals, and repeated descriptions are omitted. 5 and 6 , illustration of the control device 4 shown in FIG. 1 and the signal lines (thin solid lines) input to or output from the control device 4 are omitted.

[5-1. First modification example] In Fig. 1, the removal system 1 with only one sootblower 3 is described as an embodiment, but according to the number of pipe groups 2 or the design of the equipment, the removal system 1' with a plurality of sootblowers 3 can also be made . Generally speaking, the soot blower 3 effectively removes the adhering soot of the tube group 2 arranged close to it. Therefore, in the configuration of the removal system 1, the adhering ashes of the two tube groups 2 (the tube group 2 composed of each of the superheating tubes 22a and 22b) close to the sootblower 3a are efficiently removed. However, since the tube group 2 constituted by the superheating tube 22c located at the most downstream is arranged at a position away from the sootblower 3a, there is a possibility that the removal of adhering ash in this tube group 2 (22c) may become insufficient.

In view of this, as shown by the dotted line in Figure 1, in the removal system 1', in addition to the sootblower 3a, there is also the position of the wake of the tube group 2 (22c) [beside this tube group 2 (22c), and the Y axis The sootblowers 3' are individually arranged, whereby the adhering soot of the pipe group 2 (22c) can be removed efficiently. In addition, at this time, when the sootblower configured separately from the sootblower 3a is an impulse-pulse sootblower, the sootblower shown in the symbol 3' can also be replaced, or the sootblower shown in the symbol 3' can be replaced. In addition to the device, a sootblower is arranged at the position indicated by the symbol 3". The sootblower 3" shown by the dotted line in Fig. 1 indicates the sootblower arranged on the wall surface of the top plate of the third airway. If it is arranged in the direction of the Y-axis In addition, when the shock pulse wave is emitted downward, not only the tube group 2 (22c) but also the adhering ash of the tube group 2 (22b) arranged upstream thereof can be removed more effectively.

Even when the removal system 1' is provided with a plurality of sootblowers 3, 3', and 3", the control device 4 executes the process of Fig. 2 for each sootblower as in the above-described configuration in which only one sootblower 3 is provided. deal with. However, in the process of step S13, the control device 4 staggers the activation time points of the sootblowers 3, 3', 3" according to the arrangement of the sootblowers 3, 3', 3", and activates them one by one in sequence. That is, the control device 4 does not simultaneously The plurality of sootblowers 3, 3', 3" are activated. When a plurality of steam-type sootblowers are arranged and activated at the same time, the steam supplied from the boiler to the turbine is greatly reduced, and the amount of power generation is greatly reduced, making it difficult to transmit power stably. In addition, when a plurality of shock pulse type sootblowers are arranged and they are activated at the same time, the pressure in the furnace or the pressure in the air duct will increase significantly, and the equipment may fail. In view of this, except in the system 1', the activations of the sootblowers 3 are staggered in time and activated in sequence. The sequence in which the control device 4 sequentially activates the plurality of sootblowers 3 is the same as the second modification shown in FIG. 4 to be described later, so the description is omitted.

[5-2. Second modification example] In the removal systems 1A to 1C of the second modified example shown in FIGS. 4( a ) to 4 ( c ), with respect to the removal system 1 , the number of the tube groups 2 , the number of the sootblowers 3 and the outlet steam temperature measuring device 24 b configuration is different. In the second modification, the plurality of tube groups 2 are arranged in the Y-axis direction, that is, the vertical direction, and the plurality of sootblowers 3 are arranged. FIG. 4( a ) is a removal system 1A in which a tube group 2 composed of four superheating tubes 22 is arranged in the air passage 3 of FIG. 1 . FIG. 4( b ) is a removal system 1B in which five pipe groups 2 composed of superheating pipes 22 are arranged in the air passage 3 of FIG. 1 . FIG. 4( c ) is a removal system 1C in which a pipe group 2 composed of six superheating pipes 22 is arranged in the air passage 3 of FIG. 1 . In the second modification example, as in the first modification example, the control device 4 executes the process of FIG. 2 for each of the plurality of sootblowers.

In the removal system 1A shown in FIG. 4( a ), in addition to the configuration of FIG. 1 , the superheating pipe 22d is arranged downstream (in the Y-axis direction and above) of the tube group 2 composed of the superheating pipe 22c and adjacent thereto. The formed tube group 2. Moreover, the soot blower 3b is arrange|positioned between the pipe group 2 comprised by the superheating pipe 22c, and the pipe group 2 comprised with the superheating pipe 22d. In the removal system 1C shown in FIG. 4( c ), in addition to the configuration of FIG. 4( a ), a tube composed of superheating pipes 22e is arranged downstream of the tube group 2 composed of superheating pipes 22d and adjacent thereto. The group 2 and the tube group 2 which is arranged adjacent to the group 2 and is formed of the superheating pipes 22f are arranged downstream (in the Y-axis direction and above). Moreover, the soot blower 3d is arrange|positioned between the pipe group 2 comprised by the superheating pipe 22e, and the pipe group 2 comprised with the superheating pipe 22f. As shown in FIG. 4( a ) and FIG. 4( c ), when the number of the pipe groups 2 (here, the pipe groups 2 composed of the superheating pipes 22 ) to be removed by the sootblower 3 is plural and In the case of an even number, all the sootblowers 3 are not arranged between the target pipe groups 2 . Considering the cost-effectiveness of adhering ash removal, among the target pipe groups 2, two pipe groups 2 are arranged in sequence from the upstream pipe group 2 to form a set of units, and one sootblower 3 is arranged for each unit. Therefore, the number of the plurality of sootblowers 3 to be arranged is half of the number of the target pipe group 2 .

On the other hand, in the removal system 1B shown in FIG. 4( b ), unlike FIG. 4( c ), in the configuration of FIG. 4( a ), downstream ( In the Y-axis direction and above), only the tube group 2 formed of the superheating tubes 22e arranged adjacent thereto is added. Therefore, in FIG. 4( b ), the number of the pipe groups 2 (the pipe groups 2 composed of the superheating pipes 22 ) for removing the adhering ash by the sootblower 3 is plural and odd. In this case, a tube group 2 in which the above-mentioned "unit" cannot be formed will be generated. In Fig. 4(b), the above-mentioned "unit" cannot be created for the tube group 2 composed of the superheating tubes 22e. However, when the adhering soot of the pipe group 2 constituted by the superheating pipes 22 e cannot be relieved, the soot blower 3 c is arranged downstream of the pipe group 2 .

In the above-described second modification example, the pipe group 2 to be the object of removal of adhering ash is arranged in a row in the vertical direction (Y-axis direction). Moreover, the outlet steam temperature measuring device 24b is arrange|positioned inside the superheating pipe 22 which comprises the pipe group 2 located in the most downstream. When a certain sootblower 3 is activated to remove the adhering ash, the movement of the removed adhering ash can be assumed to be [1] a situation where it falls vertically and downward due to gravity, and [2] the flow of the exhaust gas is strong. , and the two situations are the case where the exhaust gas moves to the wake. In view of this, in the case of [1], when the control device 4 performs "one start" or "continuous start" of the sootblower 3, the sootblower 3 arranged at the most downstream is blown toward the sootblower arranged at the upstream. Device 3, start in sequence at staggered time points. That is, in the case of Fig. 4(a), after the sootblower 3b is activated, the sootblower 3a is activated again. In addition, in the case of FIG.4(b), after starting the soot blower 3c, the soot blower 3b is started again, and after starting the soot blower 3b, the soot blower 3a is started again. Similarly, in the case of FIG. 4( c ), after the sootblower 3d is activated, the sootblower 3b is activated again, and after the sootblower 3b is activated, the sootblower 3a is activated again. By activating the soot blowers 3 in this order, even if the adhering ash removed by the soot blower 3 in a certain pipe group 2 falls downward due to gravity, it is attached to another pipe group arranged upstream at the same time. In this case, it can be reliably removed including the re-adhered adhering dust. On the other hand, in the case of [2], when the control device 4 performs "one start" or "continuous start" of the sootblower 3, the sootblower 3 arranged at the most upstream is moved toward the blower arranged at the downstream. Gray device 3, start in sequence at staggered time points. That is, in the case of Fig. 4(a), after the sootblower 3a is activated, the sootblower 3b is activated again. In addition, in the case of FIG.4(b), after starting the soot blower 3a, the soot blower 3b is started again, and after starting the soot blower 3b, the soot blower 3c is started again. Similarly, in the case of Fig. 4(c), after the sootblower 3a is activated, the sootblower 3b is activated again, and after the sootblower 3b is activated, the sootblower 3d is activated again. By activating the soot blowers 3 in this order, even in a certain pipe group 2, the adhering ash removed by the soot blower 3 moves downstream along with the flow of the exhaust gas, and at the same time adheres to another one arranged downstream. In the case of a tube group, it can be reliably removed including the re-adhered ash.

In addition, in the second modification, it corresponds to the constitution of the first pipe group, the second pipe group, the third pipe group, the fourth pipe group, the first sootblower, and the second sootblower in claim 6 of this case as described below. That is, in FIG. 4(a) and FIG. 4(b), the tube group 2 constituted by the superheating tubes 22a corresponds to the first tube group, and the tube group 2 constituted by the superheating tubes 22b corresponds to the second tube group, The tube group 2 composed of the superheating tubes 22c corresponds to the third tube group, and the tube group 2 composed of the superheating tubes 22d corresponds to the fourth tube group. Further, the sootblower 3a corresponds to the first sootblower, and the sootblower 3b corresponds to the second sootblower. In Fig. 4(c), except for the same situation as Fig. 4(a) and Fig. 4(b), the tube group 2 composed of superheating tubes 22c corresponds to the first tube group and is composed of superheating tubes 22d. The pipe group 2 is equivalent to the second pipe group, the pipe group 2 formed by the superheating pipe 22e is equivalent to the third pipe group, the pipe group 2 formed by the superheating pipe 22f is equivalent to the fourth pipe group, and the soot blower 3b is equivalent to In the case of the first sootblower, the sootblower 3d is equivalent to that of the second sootblower.

[5-3. Third modification example] Next, the third modification will be described with reference to FIG. 5 . In the removal system 1D of the third modification, between the air passage 3 and the economizer 9 in FIG. 1 , a flow path of the exhaust gas extending in the horizontal direction (X-axis direction) is added, and a plurality of flow paths in the horizontal direction are also arranged. A pipe group 2 is arranged, and a plurality of soot blowers 3 are arranged. The boiler structure of the facility of the third modification is called a tail-end type. Moreover, the outlet steam temperature measuring device 24b is arrange|positioned inside the superheating pipe 22f which comprises the pipe group 2 located in the most downstream. In the third modification example, in the configuration of FIG. 4( c ), which is one of the second modification examples, from the tube group 2 composed of the superheating pipes 22c to the tube group 2 composed of the superheating pipes 22f, including The sootblowers 3b and 3d are arranged in the horizontal direction without changing the order from upstream to downstream. Here, the tube group 2 composed of the superheating pipes 22b and the tube group 2 composed of the superheating pipes 22c are assumed to be arranged adjacent to each other as in the second modification. Therefore, in the third modification, there are a plurality of tube groups 2 arranged in order from the upstream (Y-axis direction and below) to the downstream (Y-axis direction and above) in the vertical direction, and the horizontal direction is oriented in one direction (X). A plurality of tube groups 2 arranged in sequence. In addition, in the third modification example, as in the first modification example and the second modification example, the control device 4 executes the process of FIG. 2 for each of the plurality of sootblowers.

Here, attention should be paid to the plurality of tube groups 2 that are arranged in order with respect to the horizontal direction in one direction (X-axis direction), that is, the tube group 2 composed of the superheating pipes 22c and the superheating pipes 22d in FIG. 5 . In the case of the tube group 2 consisting of the superheating tubes 22e, and the tube group 2 consisting of the superheating tubes 22f, once the soot blower 3b or 3d is activated and the adhering ash is removed, the removed adhering ash There is a high possibility that it will move to the wake along with the flow of the exhaust gas. In view of this, the control device 4, when the sootblower 3 is "started once" or "continuously started", from the sootblower 3 arranged at the most upstream to the sootblower 3 arranged at the downstream, the time point is staggered according to sequence starts. That is, after the control device 4 has activated the soot blower 3b, the soot blower 3d is activated again. By activating the soot blowers 3 in this order, even in a certain pipe group 2, the adhering ash removed by the soot blower 3 moves downstream along with the flow of the exhaust gas, and at the same time adheres to another one arranged downstream. In the case of a tube group, it can be reliably removed including the re-adhered ash.

In addition, in FIG. 5 , when the plurality of tube groups 2 arranged in the horizontal direction and the plurality of tube groups 2 arranged in the vertical direction are comprehensively considered, the situation of [2] described in the second modification may occur, Therefore, the control device 4 starts the sootblowers 3 "once" or "continuously", starting from the sootblower 3 arranged most upstream toward the sootblower 3 arranged at the downstream, at a staggered time point. That is, after the control device 4 starts the soot blower 3a, it starts the soot blower 3b again, and after starting the soot blower 3b, it starts the soot blower 3d again. By activating the soot blowers 3 in this order, even in a certain pipe group 2, the adhering ash removed by the soot blower 3 moves downstream along with the flow of the exhaust gas, and at the same time adheres to another one arranged downstream. In the case of a tube group, it can be reliably removed including the re-adhered ash.

In addition, in the third modification, it corresponds to the configuration of the first pipe group, the second pipe group, the third pipe group, the fourth pipe group, the first sootblower, and the second sootblower in claim 6 of this case as described below. That is, when focusing on the plurality of tube groups 2 arranged in the horizontal direction, the tube group 2 composed of the superheating tubes 22c corresponds to the first tube group, and the tube group 2 composed of the superheating tubes 22d corresponds to the second tube group. Two pipe groups, the pipe group 2 formed by the superheating pipe 22e is equivalent to the third pipe group, the pipe group 2 formed by the superheating pipe 22f is equivalent to the fourth pipe group, the soot blower 3b is equivalent to the first soot blower, The sootblower 3d corresponds to the second sootblower. In addition, when the plurality of tube groups 2 arranged in the horizontal direction and the plurality of tube groups 2 arranged in the vertical direction are comprehensively considered, in FIG. 5 , the tube group 2 constituted by the superheating tubes 22 a corresponds to the first tube The tube group 2 constituted by the superheating tubes 22b corresponds to the second tube group, the tube group 2 constituted by the superheating tubes 22c corresponds to the third tube group, and the tube group 2 constituted by the superheating tubes 22d corresponds to the fourth tube group In the tube group, the soot blower 3a corresponds to the first soot blower, and the soot blower 3b corresponds to the second soot blower. According to the removal system 1D of the third modification, in addition to the effects obtained by the above-described embodiment, the adhered dust can be reliably removed including the re-adhered adhered dust.

[5-4. Fourth modification example] Next, the fourth modification will be described with reference to FIG. 6 . The removal system 1E of the fourth modification is that in the third modification, the flow path of the exhaust gas extending in the horizontal direction between the air passage 3 and the economizer 9 is removed, and replaced by the air passage 3 and the economizer 9 . It is a configuration in which a double-drum boiler provided with a steam drum 19 and a water drum 20 is installed. By removing the flow path, the tube group 2 (22c to 22f) and the sootblowers 3 (3b, 3d) arranged in the flow path in the third modification are also removed. In addition, in the fourth modification, the suspension pipe 21 and the soot blower 3a of the third modification are removed, and the superheating pipes 22a and 22b are suspended and arranged on the ceiling plate of the air passage 3, and the superheating pipes 22a and 22a are placed upstream and The sootblowers 3 (3e) are arranged adjacent to the superheating pipes 22a. 1, the pipe group 2 of the economizer 9 is not considered as the pipe group to which the adhered ash is removed, but in the fourth modification, the plurality of pipe groups 2 of the heat saver 9 are also set as the adhered ash. removed object. Therefore, the plurality of pipe groups 2 arranged in the vertical direction (Y-axis direction) inside the economizer 9, that is, the pipe group 2 constituted by the water pipes 23a, are arranged adjacent to the pipe group 2. A soot blower 3f is installed downstream between the pipe group 2 formed of the water pipes 23b. Also in this case, as described above, the "plurality of pipe groups 2" that are the objects of removal of adhering ash are arranged between the two pressure measuring devices 14a and 14b, and the two gas temperature measuring devices 15a and 15b. between. In FIG. 6 , the pipe group 2 that is the object of removal of adhering ash includes different types of pipe groups 2 , that is, the pipe group 2 composed of the superheating pipes 22 and the pipe group 2 composed of the water pipes 23 . In addition, between the pipe group 2 formed of the superheating pipe 22 (22b) and the pipe group 2 formed of the water pipe 23 (23a), another pipe group 2 serving as a resistance to the flow of the exhaust gas is not arranged. 1, the temperature measuring device 15b for measuring the temperature of the exhaust gas at the "outlet" of the plurality of pipe groups 2 is arranged in the object of the removal of adhering ash, that is, among the plurality of pipe groups 2, by the water pipe 23b disposed at the most downstream downstream of the formed tube group 2 . In FIG. 6 , the temperature measuring device 15b is disposed at substantially the same position as the pressure measuring device 14b in FIG. 1 . Moreover, in the superheating pipe 22b located in the most downstream among the superheating pipes 22, the outlet steam temperature measuring apparatus 24b is arrange|positioned. In addition, also in the fourth modification, as in the first modification to the third modification, the control device 4 executes the process of FIG. 2 for each of the plurality of sootblowers.

In the fourth modification, when the control device 4 performs "one start" or "continuous start" of the sootblower 3, the time from the most upstream sootblower 3 to the downstream sootblower 3 Start sequentially at staggered time points. That is, after the control device 4 starts the soot blower 3e, it starts the soot blower 3f again. By activating the soot blowers 3 in this order, even if the adhering ash removed by the soot blower 3 in the pipe group 2 arranged upstream moves downstream by the flow of the exhaust gas, it re-adheres to the soot blower arranged downstream. In the case of another tube group, it can be reliably removed including the re-adhered ash.

In addition, the fourth modification corresponds to the constitution of the first pipe group, the second pipe group, the third pipe group, the fourth pipe group, the first sootblower, and the second sootblower in claim 7 of this case as described below. That is, the pipe group 2 formed of the superheating pipes 22a corresponds to the first pipe group, the pipe group 2 formed of the superheating pipes 22b corresponds to the second pipe group, and the pipe group 2 formed of the water pipes 23a corresponds to the third pipe group. The pipe group, the pipe group 2 formed by the water pipes 23b corresponds to the fourth pipe group, the soot blower 3e corresponds to the first soot blower, and the soot blower 3f corresponds to the second soot blower. According to the removal system 1E of the fourth modification, in addition to the effects obtained by the above-described embodiment, the adhered dust can be reliably removed including the re-adhered adhered dust.

The embodiments and modifications of the present invention have been described above, but the technical scope of the present invention is not limited to the embodiments and modifications, and various modifications can be added without departing from the gist of the present invention.

1, 1', 1A~1E: Boiler tube group adhering ash removal system (removal system) 2: Tube group 3,3',3",3a~3f: Soot blower 4: Control device 5: Hopper 6: Feeder 7: Grate 8: Ash tank 9: Economizer (a kind of tube group) 10: Cooling tower 11: Dust removal device (bag filter) 12: Chimney 13: induced draft fan 14a, 14b: Pressure measuring device 15a, 15b: Gas temperature measuring device 16a, 16b: Gas flow measuring device 17: Overheating return device 18: Spray water volume measuring device 19: Steam drum 20: Water drum 21: Suspension tube (screen tube) 22a~22f: Overheating pipe (superheater) 23a, 23b: Water pipes 24a, 24b: Vapor temperature measuring device 25: Main steam volume measuring device 26: Primary air supply device 27: Secondary air supply device 28: Combustion air volume measuring device K: heat transfer coefficient Kc: clean heat transfer coefficient Kd: fouling heat transfer coefficient Kc/Kd: recovery rate ΔPg: Differential pressure p gmin: second threshold Qc: Total Combustion Air q cmin: the fourth threshold Qr: The number of revolutions of the induced draft fan q rmin: the third threshold Qs: main steam volume q smin: first threshold R: recovery threshold α1: First specified value α2: Second specified value

1 is a schematic configuration diagram of a boiler tube group adhering ash removal system according to the embodiment and the first modification. [ Fig. 2 ] An example of a flowchart illustrating the control of the sootblower activation of the boiler tube group adhering ash removal system. [ Fig. 3] Figs. 3(a) to 3(d) are examples of a specific processing flow of step S16 (adhered dust determination processing) in Fig. 2 . [Fig. 4] Fig. 4(a) to Fig. 4(c) are partial schematic configuration diagrams of a boiler tube group adhering ash removal system according to a second modification. [ Fig. 5] Fig. 5 is a schematic configuration diagram of a boiler tube group adhering ash removal system according to a third modification. [ Fig. 6] Fig. 6 is a schematic configuration diagram of a boiler tube group adhering ash removal system according to a fourth modification.

1,1': Boiler tube group adhering ash removal system (removal system)

2: Tube group

3,3',3",3a: Sootblower

4: Control device

5: Hopper

6: Feeder

7: Grate

8: Ash tank

9: Economizer (a kind of tube group)

10: Cooling tower

11: Dust removal device (bag filter)

12: Chimney

13: induced draft fan

14a, 14b: Pressure measuring device

15a, 15b: Gas temperature measuring device

16a, 16b: Gas flow measuring device

17: Overheating return device

18: Spray water volume measuring device

21: Suspension tube (screen tube)

22a~22c: Overheating pipe (superheater)

24a, 24b: Vapor temperature measuring device

25: Main steam volume measuring device

26: Primary air supply device

27: Secondary air supply device

28: Combustion air volume measuring device

Claims (8)

A boiler tube group adhering ash removal system for removing adhering ash from a plurality of tube groups of a boiler for heat recovery from flue gas generated in a boiler, characterized by comprising: a soot blower, arranged between the aforementioned plurality of pipe groups; an induced draft fan, disposed downstream of the plurality of pipe groups, to induce the exhaust gas; and a control device to control the activation of the aforementioned sootblower; The aforementioned control device is Calculate the heat transfer coefficient of the aforementioned boiler, When the calculated heat transfer coefficient is greater than or equal to a predetermined value, the sootblower is activated once, that is, the sootblower is activated only once after a predetermined period of time, and then again after the predetermined period of time or a different one. period, When the calculated heat transfer coefficient is less than the predetermined value, the adhering dust determination process is executed to determine one of the first determination and the second determination. When the first determination is obtained by the adhering ash determination process, continuous activation is performed, that is, the sootblower is continuously activated multiple times without intervals of the foregoing period. In the case where the second judgment is obtained by the above-mentioned adhering dust judgment processing, the above-mentioned one activation is executed, The deposition ash determination process includes a first condition that the main steam amount of the plurality of pipe groups is equal to or greater than a first threshold value, and a second condition that the pressure difference of the exhaust gas between the inlet and the outlet of the plurality of pipe groups is equal to or greater than a second threshold value. Two conditions, the third condition that the number of revolutions of the aforementioned induced draft fan is equal to or higher than the third threshold value, and the fourth condition that the total amount of combustion air supplied to the aforementioned furnace is equal to or higher than the fourth threshold value, is executed, In the case where the adhering ash determination process is performed based on only one of the four aforementioned conditions, the aforementioned first determination is obtained when the aforementioned one condition is satisfied, and the aforementioned second determination is obtained when the aforementioned one condition is not satisfied, In the case where the above-mentioned adhering dust determination processing includes 2, 3, or 4 conditions among the above-mentioned 4 conditions, and all the conditions including the above-mentioned 2, 3, or 4 conditions are satisfied, the above-mentioned condition is obtained. In the first judgment, the second judgment is obtained when any one of the above-mentioned two, three, or four conditions is not satisfied. The boiler tube group adhering ash removal system according to claim 1, wherein the control device is a When the first determination is obtained by the adhering dust determination process, the dirty heat transfer coefficient of the heat transfer coefficient calculated before the activation of the sootblower is calculated, and the calculation is performed after the activation of the sootblower. Calculate the recovery rate by calculating the clean heat transfer coefficient of the aforementioned heat transfer coefficient, When the aforementioned recovery rate is greater than or equal to the recovery threshold, the aforementioned continuous startup is performed, When the aforementioned recovery rate is less than the aforementioned recovery threshold, the aforementioned one activation is performed. The boiler tube group adhering ash removal system according to claim 2, wherein, when the clean heat transfer coefficient is equal to or greater than the predetermined value, the control device extends the predetermined period from a previously set value and then resets the It is set that, when the recovery rate is equal to or greater than the recovery threshold, the predetermined period is set shorter than the previously set value. The boiler tube group adhering ash removal system according to claim 3, wherein the control device reduces the number of starts during the continuous start when the rate of increase of the recovery rate is large during the continuous start, and when the When the rate of increase of the recovery rate is small, the number of consecutive starts is increased. The boiler tube group adhering ash removal system according to claim 4, further comprising: a bag filter disposed downstream of the plurality of tube groups to remove soot from the exhaust gas, The aforementioned control device does not start the aforementioned soot blower while the backwashing of the aforementioned bag filter is being performed, and then starts the aforementioned sootblower after the aforementioned backwashing is completed. The boiler tube group adhering ash removal system according to claim 5, wherein the plurality of tube groups includes a first tube group and a second tube group disposed downstream of the first tube group and adjacent to the first tube group A pipe group, a third pipe group arranged downstream of the second pipe group and adjacent to the second pipe group, and a fourth pipe group downstream of the third pipe group and adjacent to the third pipe group , The sootblower includes a first sootblower disposed between the first pipe group and the second pipe group, and a second sootblower disposed between the third pipe group and the fourth pipe group , The aforementioned control device, when the aforementioned first sootblower and the aforementioned second sootblower are started once or continuously started, When the first pipe group to the fourth pipe group are arranged in order from the bottom to the top in the vertical direction, after the second soot blower is activated, the first soot blower is activated, or the first soot blower is activated. After the soot blower, start the second soot blower, When the first pipe group to the fourth pipe group are arranged in sequence in a horizontal direction, after starting the first sootblower, the second sootblower is started again. When the first tube group and the second tube group are arranged in order from the bottom to the upper direction in the vertical direction, and the third tube group and the fourth tube group are arranged in this order in the horizontal direction, the above-mentioned tube group is activated. After the first sootblower, the aforementioned second sootblower is activated. The boiler tube group adhering ash removal system according to claim 5, wherein the plurality of tube groups includes a first tube group and a second tube group disposed downstream of the first tube group and adjacent to the first tube group A pipe group, a third pipe group arranged downstream of the second pipe group, and a fourth pipe group downstream of the third pipe group and adjacent to the third pipe group, The sootblower includes a first sootblower disposed upstream of the first pipe group and adjacent to the first pipe group, and a second sootblower disposed between the third pipe group and the fourth pipe group ashes, The aforementioned control device starts the aforementioned second sootblower after starting the aforementioned first sootblower when the aforementioned first sootblower and the aforementioned second sootblower are started once or continuously. The boiler tube group adhering ash removal system according to any one of claim 1 to claim 7, wherein the sootblower is a pressure wave type sootblower that generates pressure waves by detonating gas.

Images