WO2021039031A1

WO2021039031A1 - Soot blower control system

Info

Publication number: WO2021039031A1
Application number: PCT/JP2020/023412
Authority: WO
Inventors: 智弘土井; 宏権藤
Original assignee: 三菱パワー株式会社
Priority date: 2019-08-26
Filing date: 2020-06-15
Publication date: 2021-03-04
Also published as: TWI755784B; KR102647151B1; JP6808001B1; TW202117232A; MX2022001148A; JP2021032497A; KR20220027999A

Abstract

The present invention increases the operation efficiency of a soot blower while suppressing a change in the steam temperature of a heat transfer tube. This soot blower control system is provided with: a soot blower (30) that jets steam onto the surface of a heat transfer tube (6); an inlet temperature sensor (20d) that detects the steam inlet temperature (T_in) of the heat transfer tube; an outlet temperature sensor (20e) that detects the steam outlet temperature (T_out) of the heat transfer tube; and a controller (100). The soot blower control system is characterized in that the controller calculates a temperature change value (dT) which is the difference between a first temperature difference (ΔT1) and a second temperature difference (ΔT2), which are differences between the steam inlet temperature and the steam outlet temperature at a first time point and a second time point, respectively, during operation of the soot blower and determines an operation interval of the soot blower so as to keep the temperature change value within the range of a target value.

Description

Soot blower control system

The present invention relates to a soot blower control system.

A boiler that burns solid fuel such as pulverized coal injects pulverized solid fuel into the fireplace from a fuel burner and burns it in the fireplace. The boiler is provided with a large number of heat transfer tubes that make up a superheater and a reheater, and ash and the like burned during boiler operation adhere to the heat transfer tubes as clinker. If the boiler is continued to operate with the clinker attached to the heat transfer tube, the heat exchange efficiency of the heat transfer tube will decrease. Therefore, the clinker adhering to the heat transfer tube is removed by operating the soot blower on a regular basis.

As a method for controlling the soot blower, for example, in Patent Document 1, the steam temperature at the outlet of the boiler when the soot blower is operated is measured, and the fluctuation range of the maximum deviation between the measured value and the predetermined control value is obtained. , It is described that the injection fluid pressure at the time of the next operation of the soot blower is increased or decreased from the previous injection fluid pressure according to the range of the maximum fluctuation range.

According to the control method described in Patent Document 1, since the injection fluid pressure of the soot blower can be adjusted, fluctuations in the steam temperature and steam pressure at the boiler outlet due to the operation of the soot blower can be suppressed.

Japanese Patent No. 3615776

However, in Patent Document 1, since the operation interval of the soot blower is fixed, there is room for improvement in order to operate the soot blower efficiently.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a control system for a soot blower capable of improving the operating efficiency of the soot blower while suppressing a change in the steam temperature of a heat transfer tube due to the operation of the soot blower. To provide.

In order to achieve the above object, a typical present invention includes a soot blower that injects steam onto the surface of a heat transfer tube provided in a boiler, an inlet temperature sensor that detects the steam inlet temperature of the heat transfer tube, and the transfer. In a soot blower control system including an outlet temperature sensor that detects the steam outlet temperature of a hot tube, and a controller that controls the operation of the soot blower based on each detection signal input from the inlet temperature sensor and the outlet temperature sensor. In the controller, the first temperature difference, which is the difference between the steam inlet temperature and the steam outlet temperature at the first time point during the operation of the sootblower, and the steam at the second time point during the operation of the sootblower. The temperature change value, which is the difference between the inlet temperature and the second temperature difference, which is the difference between the steam outlet temperature, is obtained, and the operation interval of the soot blower is determined so that the temperature change value is within the target value range. It is characterized by doing.

According to the control system of the soot blower according to the present invention, it is possible to improve the operation efficiency of the soot blower while suppressing the change in the steam temperature of the heat transfer tube due to the operation of the soot blower. Issues, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

It is a side view which shows the whole structure of the boiler to which this invention is applied. It is a steam system diagram of a boiler. It is a figure which shows typically the structure of a soot blower. It is a block diagram which shows the electrical structure of a controller. It is a flowchart which shows the procedure of determination process of the operation schedule of the soot blower in 1st Embodiment. It is a figure which shows the operation schedule of the conventional soot blower. It is a figure which shows the operation schedule of the soot blower in 1st Embodiment. It is a figure which shows the display example of a monitor. It is a figure which shows the display example of the next page of a monitor. It is a flowchart which shows the procedure of determination process of the operation schedule of the soot blower in 2nd Embodiment. It is a figure which shows the correspondence relationship between an operation mode and a target value. It is a flowchart which shows the procedure of determination process of the operation schedule of the soot blower in 3rd Embodiment. It is a figure which shows the correspondence relationship between the operation mode and the spray steam pressure. It is a flowchart which shows the procedure of determination process of the operation schedule of the soot blower in 4th Embodiment. It is a figure which shows the correspondence relationship between an operation mode and a rotation speed.

(First Embodiment)
Hereinafter, embodiments of the sootblower control system according to the present invention will be described with reference to the drawings. FIG. 1 is a side view showing the overall configuration of a boiler to which the present invention is applied. As shown in FIG. 1, the boiler 1 includes a fireplace 2, a cage portion 3, and a sub-side wall 4 connecting the fireplace 2 and the cage portion 3. The fireplace 2 is provided with a wind box 5 for blowing air into the fireplace 2, and a burner (not shown) for blowing pulverized coal, which is a solid fuel, into the fireplace 2 and burning the air box 5 is provided. Has been done. Further, a plurality of heat exchangers including a large number of heat transfer tubes (heat transfer tube group) 6 are installed inside the fireplace 2, the sub-side wall 4, and the cage portion 3. These heat exchangers include a primary superheater 13, a secondary superheater 14, a tertiary superheater 15, a primary reheater 16, a secondary reheater 17, and an economizer 10 (see FIG. 2).

While introducing air from the wind box 5 into the fireplace 2, when fuel is injected from the burner and the pulverized coal burns in the fireplace 2, high-temperature combustion gas is generated. The combustion gas generated in the fireplace 2 flows in the order of the fireplace 2, the sub-side wall 4, and the cage portion 3, and is finally discharged to the outside through a chimney (not shown). The high-temperature combustion gas exchanges heat with the fluid in the heat transfer tube 6 in the process of flowing through the fireplace 2, the auxiliary side wall 4, and the cage portion 3. This produces high temperature superheated steam.

Next, the steam system of the boiler 1 will be described. FIG. 2 is a steam system diagram of the boiler 1 shown in FIG. As shown in FIG. 2, the water supplied from the water supply line is the economizer 10, the furnace wall (water wall) 11, the steam separator 12, the primary superheater 13, the secondary superheater 14, and the tertiary superheater 15. During the sequential flow, heat is exchanged with the combustion gas to become high-temperature, high-pressure superheated steam, which is supplied to the high-pressure turbine 18. Further, the steam taken out from the high pressure turbine 18 exchanges heat with the combustion gas while flowing in the order of the primary reheater 16 and the secondary reheater 17, becomes reheated steam, and is supplied to the low pressure turbine 19 after being supplied to the low pressure turbine 19. Returned to the condenser. Temperature sensors 20a to 20i for detecting the steam temperature are provided at the steam inlet / outlet of each heat exchanger.

Returning to FIG. 1, the boiler 1 is provided with a large number of soot blowers 30A, B, C ..., 40A, B, C ... In the following description, when it is not necessary to distinguish the soot blowers 30A, B, C ..., It may be simply referred to as the soot blower 30. The same applies to the soot blowers 40A, B, C ...

The soot blower 30 is for removing clinker adhering to the surface of each heat transfer tube 6 constituting each

heat exchanger

10, 13, 14, 15, 16 and 17, and the soot blower 40 is attached to the inner wall of the fireplace wall 11. It is for removing the clinker.

Next, the structure of the soot blower 30 will be described. FIG. 3 is a diagram schematically showing the structure of the soot blower 30 shown in FIG. Since the soot blower 40 has the same structure as the soot blower 30, the description thereof will be omitted.

As shown in FIG. 3, the soot blower 30 includes a nozzle block 32 having

spray holes

33 and 34, a soot blower tube 31 whose tip is connected to the nozzle block 32 (a tube through which steam for soot blower flows) 31, and a motor 38. And. The motor 38 and the soot blower tube 31 are connected via a power transmission mechanism such as a gear (not shown), and the rotation of the motor 38 causes the soot blower tube 31 to rotate around the central axis and move in the insertion / removal direction (axial direction). It is possible to move.

The motor 38 is driven via the inverter 39 based on a command from the controller 100. The rear end of the soot blower tube 31 is connected to the spray steam supply line 35, and steam having a pressure adjusted by the steam pressure control valve 37 flows through the soot blower tube 31 and is sprayed into the furnace 2 from the spray holes 33 and 34. It has a structure of By spraying steam from the spray holes 33 and 34 to the heat transfer tube 6, the clinker adhering to the heat transfer tube 6 is removed. The detection signal of the pressure sensor 36 is input to the controller 100, and the controller 100 controls the steam pressure control valve 37 to a desired opening degree. As a result, the pressure and flow rate of the steam sprayed from the soot blower 30 are adjusted.

FIG. 4 is a block diagram showing the electrical configuration of the controller 100. As shown in FIG. 4, the controller 100 is a storage device such as a CPU 100a that performs calculations for determining the operation schedules of the

soot blowers

30 and 40, which will be described later, and a ROM, HDD, or the like that stores a program for executing the calculations by the CPU 100a. Stored in the storage device 100b and hardware including 100b, RAM 100c which is a work area when the CPU 100a executes a program, and a communication interface (communication I / F) 100d which is an interface when transmitting and receiving data to and from other devices. It is composed of software that is executed by the CPU 100a. Each function of the controller 100 is realized by the CPU 100a loading various programs stored in the storage device 100b into the RAM 100c and executing them.

The controller 100 includes a temperature sensor 20a for detecting the water inlet temperature of the coal saver 10, a temperature sensor 20b for detecting the cooling water inlet temperature of the furnace wall 11, and a temperature sensor 20c for detecting the steam inlet temperature of the primary heater 13. Temperature sensor 20d that detects the steam outlet temperature of the primary superheater 13 (steam inlet temperature of the secondary superheater 14), temperature sensor that detects the steam outlet temperature of the secondary superheater 14 (steam inlet temperature of the tertiary superheater 15) 20e, temperature sensor 20f for detecting the steam outlet temperature of the tertiary superheater 15, temperature sensor 20g for detecting the steam inlet temperature of the primary reheater 16, steam outlet temperature of the primary reheater 16 (of the secondary reheater 17) The detection signals from the temperature sensor 20h that detects the steam inlet temperature) and the temperature sensor 20i that detects the steam outlet temperature of the secondary reheater 17 are input. In addition, information on the type of coal to be put into the boiler 1 and information on the operation mode are also input to the controller 100.

Then, the controller 100 drives the inverter 39 of the desired

soot blowers

30 and 40 to rotate the motor 38 according to the operation schedule of the

soot blowers

30 and 40 described below. That is, the controller 100 individually controls the operation of the

soot blowers

30 and 40.

Further, a detection signal from the pressure sensor 36 is input to the controller 100, and the controller 100 controls the opening degree of the steam pressure control valve 37 based on the detection signal. The controller 100 is connected to the monitor 50, and the calculation result by the controller 100 is appropriately displayed on the monitor 50 (see FIGS. 7 and 8).

Next, the procedure for determining the operation schedule of the

soot blowers

30 and 40 will be described. FIG. 5 is a flowchart showing a procedure for determining the operation schedule of the

soot blowers

30 and 40. The controller 100 executes the process shown in FIG. 5 for each operation of the

soot blowers

30 and 40, and when a predetermined period (3 days in the present embodiment) elapses from the operation of the first soot blower 30 in the current operation schedule, the next operation is performed. Create an operation schedule for the

soot blowers

30 and 40 for 3 days. The operation schedule of the

soot blowers

30 and 40 for the first 3 days when the boiler 1 is started is set in advance. For example, in the present embodiment, the operation schedule of all the

soot blowers

30 and 40 is operated every 9 hours. Is preset. Therefore, in the present embodiment, all the

soot blowers

30 and 40 are operated every 9 hours for the first 3 days from the start of the boiler 1, and from the 4th day onward, the

soot blowers

30 and 40 are operated according to the operation schedule based on the temperature change of the heat transfer tube 6. 40 will be operated individually.

When the operation of the

soot blowers

30 and 40 is started, the controller 100 starts the process of FIG. Here, the procedure for determining the operation schedule will be described by taking the soot blower 30 installed for the secondary superheater 14 as an example, but for the

other soot blowers

30 and 40, the procedure is the same for each of the

soot blowers

30 and 40. The operation schedule is decided.

First, the controller 100 is operated at the start of the soot blowers 30 steam inlet temperature _{T in} of the secondary superheater 14 (heat transfer tube 6) of the (first time operation) acquired from the temperature sensor 20d, the secondary superheater 14 The steam outlet temperature To _out is acquired from the temperature sensor 20e. Then, the controller 100 calculates the temperature difference between the steam inlet temperature _{T in} the steam outlet temperature _{T out} Delta] T1 (first temperature difference), and stores the temperature difference Delta] T1 to RAM 100c (step S1).

Next, the controller 100 obtains the steam inlet temperature _{T in} upon stopping of the sootblower 30 (second operating state) of the secondary superheater 14 (heat transfer tube 6) from the temperature sensor 20d, the secondary superheater 14 The steam outlet temperature To _{out of} is acquired from the temperature sensor 20e. Then, the controller 100 calculates the temperature difference between the steam inlet temperature _{T in} the steam outlet temperature _{T out} Delta] T2 (second temperature difference), and stores the temperature difference Delta] T2 in RAM 100c (step S2). The processing of steps S1 and S2 is not limited to the start of operation and the stop of operation of the soot blower 30.

Next, the controller 100 calculates the difference between the temperature difference ΔT2 and the temperature difference ΔT1, that is, the temperature change value dT (= ΔT2-ΔT1), and stores the temperature change value dT in the RAM 100c (step S3). When three days have passed from the operation of the first soot blower 30 in the current operation schedule (step S4 / YES), the controller 100 reads out the temperature change value dT for three days (integrated time H) stored in the RAM 100c. The integrated value ΣdT of the temperature change value dT for 3 days is calculated (step S5).

Next, the controller 100, the interval time of the sootblowers 30, based on the accumulated ΣdT temperature change value dT to calculate the _{(headway) T int2} (step S6), and determines the operation schedule of the sootblowers 30 next 3 days ( Step S7). According to this operation schedule, the controller 100 controls the operation of the soot blower 30 for the next three days. That is, the soot blower 30 is operated every _{interval time Tint2 calculated in step S6.} If three days have not passed in step S4 (step S4 / No), the controller 100 ends the process and waits until the next start of operation of the soot blower 30.

Next, a method of calculating the _{interval time Tint2 in step S6 will be described.} The integration time is H, the integration value is ΣdT, the target value of the temperature change of ^{the heat transfer tube 6 is T *} , the number of heat transfer tubes 6 is N, the operation interval of the soot blower this time (this interval time) is _Tint1 , and the next interval. time _{T int2,} if the expected value is _{E x,} the next time interval _{T int2} the formula (1) is calculated by (2).
E _x = T ^* / N × H / T _int1 ... (Equation 1)
_{_{T int2 = T int1 / (ΣdT}} / E x) ··· ( Equation 2)

For example, target value T ^* = 2 ° C., integrated time H = 72 hours (3 days), integrated value ΣdT = 0.77 ° C., number of heat transfer tubes N = 12 (6 pairs), current interval time _Tint1 = In the case of 9 hours (initial value), the expected value _Ex = 2 ° C./12 pieces x 72 hours / 9 hours = 1.3 can be obtained from (Equation 1). By substituting this expected value _Ex = 1.3 into (Equation 2), the next interval time _Tint2 = 9h / (0.77 ° C./1.3) = 15.2 hours.

The controller 100 performs this calculation on all the soot blowers 30A, B, C, D, E ..., And determines the operation schedule of each soot blower. For example, for the soot blowers 30A, B, C, D, and E, the integrated values ΣdT for the three days this time were 0.77 (described above), 0.33, 1.13, 0.54, and 1.92, respectively. Then, the controller 100 _{calculates the next interval time Tint2} as 15.2 hours (described above), 35.5 hours, 10.4 hours, 21.7 hours, and 6.1 hours, respectively. Therefore, the soot blowers 30A, B, C, D, and E are individually operated for the next three days at the _{calculated next interval time Tint2.}

The operation schedule of the soot blower in this embodiment will be described in comparison with the conventional one. FIG. 6A is a diagram showing an operation schedule of a conventional soot blower, and FIG. 6B is a diagram showing an operation schedule of the soot blower in the present embodiment. 6A and 6B show the operation schedule for five soot blowers (SB).

As shown in FIG. 6A, conventionally, all the soot blowers A to E were operated in order at intervals of 9 hours. Therefore, conventionally, the operation schedule has been such that the soot blower is operated in the order of A → B → C → D → E every 9 hours.

On the other hand, in the present embodiment, as described above, the interval time of the soot blowers 30A, B, C, D, E (hereinafter abbreviated as A, B, C, D, E) is determined individually, so that the interval time is 3 days. The operation schedule of the soot blowers A to E is as shown in FIG. 6B. That is, the soot blower A is operated every 15.2 hours, the soot blower B is operated every 35.5 hours, the soot blower C is operated every 10.4 hours, and the soot blower D is operated every 21.7 hours. The soot blower E is operated every 6.1 hours. Therefore, the operation order for 3 days is E-> A-> E-> D-> C-> E ....

Next, a display example of the monitor 50 will be described. The controller 100 displays the integrated value ΣdT of each of the

soot blowers

30 and 40 in a predetermined display area of the monitor 50. FIG. 7 is a diagram showing a display example of the monitor 50. As shown in FIG. 7, a schematic view of the side surface of the boiler 1 is displayed on the monitor 50, and a display area 60 for displaying the temperature information of the heat transfer tube 6 is provided at a position where the

soot blowers

30 and 40 are arranged. It is formed. The controller 100 calculates the integrated value ΣdT as described above, and controls the integrated value ΣdT to be displayed in a predetermined display area 60 corresponding to the arrangement of the

soot blowers

30 and 40. Since the integrated value ΣdT is calculated once every three days, the integrated value ΣdT displayed in the display area 60 is also updated every three days. The display area 60 is color-coded according to the integrated value ΣdT, which makes it easy to visually grasp the temperature distribution.

In addition, a display area 65 is provided at the lower right of the monitor 50, and the characters "next page" are displayed in this display area 65. When the display area 65 is touch-operated, for example, the screen display is switched. FIG. 8 is a diagram showing a display example on the next page of the monitor 50. As shown in FIG. 8, when the screen of the monitor 50 is switched, the integrated value ΣdT for each type of coal (coal type), which is the fuel information of the boiler 1, is displayed. In the example of FIG. 8, the integrated value ΣdT of the temperature change value dT of the heat transfer tube 6 corresponding to each of the soot blowers A, B, C, C, and E is the coal type (coal type) No. 1 to No. It is displayed every 4. Although not shown, the display is color-coded according to the temperature value.

According to the present embodiment configured in this way, the following effects can be achieved.

When the clinker adhering to the heat transfer tube 6 is removed, the heat transfer efficiency of the heat transfer tube 6 is improved. Therefore, the steam outlet temperature of the heat transfer tube 6 is set before operating the soot blowers 30 and 40 (that is, the clinker adhering to the heat transfer tube 6). It rises compared to before removing). The change in the steam outlet temperature of the heat transfer tube 6 increases as the amount of clinker removed from the heat transfer tube 6 increases. Considering the stable operation of the boiler 1, it is preferable that the temperature change at the steam inlet / outlet of the heat transfer tube 6 is small, but if the operation interval of the soot blower is fixed as in the conventional case, the steam temperature of each heat transfer tube 6 It is difficult to manage.

Therefore, in the present embodiment, the operation interval (interval time) of each soot blower 30, 40 (30A, B, C ..., 40A, B, C ...) is obtained by the above-mentioned calculation method, and the operation schedule is obtained. The

soot blowers

30 and 40 are controlled to be operated according to the above.

As a result, for the heat transfer tube 6 to which the clinker easily adheres, the temperature rise of the heat transfer tube 6 can be suppressed by frequently operating the

soot blowers

30 and 40 to remove the clinker. Further, for the heat transfer tube 6 to which the clinker is hard to adhere, the operation of the

soot blowers

30 and 40 can be suppressed by lengthening the operation interval of the

soot blowers

30 and 40. As described above, in the present embodiment, it is possible to improve the operating efficiency of the

soot blowers

30 and 40 while suppressing the change in the steam outlet temperature of the heat transfer tube 6 before and after the operation of the

soot blowers

30 and 40.

Further, a schematic diagram of the boiler 1 is displayed on the monitor 50, and the integrated value ΣdT is displayed in association with the positions of the

soot blowers

30 and 40 installed in the boiler 1, so that the temperature change of the heat transfer tube 6 in any area is displayed. It is easy to visually check if the size is large. Further, since the temperature is displayed in different colors according to the integrated value ΣdT, it is easy to visually grasp the distribution of the temperature change, and the operation management of the boiler 1 is easy. Further, when the screen of the monitor 50 is switched, the integrated value ΣdT is displayed in a list according to the type of coal, so that the

optimum soot blowers

30 and 40 can be operated according to the type of coal.

(Second Embodiment)
Next, the control system of the soot blower according to the second embodiment of the present invention will be described. The soot blower control system according to the second embodiment is characterized in that the controller 100 changes the ^{target value T * according to the operation mode.} Hereinafter, this feature will be mainly described.

FIG. 9 is a flowchart showing a procedure for determining the operation schedule of the soot blower according to the second embodiment. As shown in FIG. 9, the second ^{embodiment is different from the first embodiment in that the target value T *} is changed according to the operation mode of the boiler 1 (step S6-1).

FIG. 10 is a diagram showing a correspondence relationship between the operation mode and the target value T ^*. As shown in FIG. 10, the target value T ^* = 2 ° C. corresponds to the operation mode a, the target value T ^* = 3 ° C. corresponds to the operation mode b, and the target value T ^* = 4 ° C. corresponds to the operation mode c. The attached table is stored in the storage device 100b in advance. When the controller 100 executes the process of step S6-1, the controller 100 ^{reads the target value T *} corresponding to the input operation mode from the storage device 100b, substitutes it into ^{the T *} of the above (Equation 1), and expects it. The value _Ex is calculated, and finally, the next interval time _Tint2 is calculated.

_{According to this second embodiment, the soot blowers 30 and 40 can be operated at a more suitable interval time Tint2} according to the operation mode, so that the operation efficiency of the

soot blowers

30 and 40 is further improved.

(Third Embodiment)
Next, the control system of the soot blower according to the third embodiment of the present invention will be described. The soot blower control system according to the third embodiment is characterized in that the controller 100 changes the spray steam pressures P of the

soot blowers

30 and 40 according to the operation mode. Hereinafter, this feature will be mainly described.

FIG. 11 is a flowchart showing a procedure for determining the operation schedule of the soot blower according to the third embodiment. As shown in FIG. 11, in the third embodiment, after the next interval time _Tint2 is calculated, the spray steam pressures P of the

soot blowers

30 and 40 are determined according to the operation mode (step S6-2). There is a feature in.

FIG. 12 is a diagram showing the correspondence between the operation mode and the spray vapor pressure P. As shown in FIG. 12, the spray vapor pressure P = Pa is associated with the operation mode a, the spray vapor pressure P = Pb is associated with the operation mode b, and the spray vapor pressure P = Pc is associated with the operation mode c. The table is stored in the storage device 100b in advance. The controller 100 selects the spray steam pressure P of the

soot blowers

30 and 40 according to the operation mode in step S6-2, and the steam pressure control valve so that the pressure of the spray steam supply line 35 becomes the selected spray steam pressure P. Adjust the opening degree of 37.

According to this third embodiment, since the steam pressure sprayed from the

soot blowers

30 and 40 can be adjusted, it is possible to finely suppress the change in the steam temperature of the heat transfer tube 6 according to the operation mode.

(Fourth Embodiment)
Next, the control system of the soot blower according to the fourth embodiment of the present invention will be described. The soot blower control system according to the fourth embodiment is characterized in that the controller 100 changes the rotation speeds N of the

soot blowers

FIG. 13 is a flowchart showing a procedure for determining the operation schedule of the soot blower according to the fourth embodiment. As shown in FIG. 13, in the fourth embodiment, after the next interval time _Tint2 is calculated, the rotation speeds N of the

soot blowers

30 and 40 are determined according to the operation mode (step S6-3). There is a feature.

FIG. 14 is a diagram showing the correspondence between the operation mode and the rotation speed N. As shown in FIG. 12, a table in which the rotation speed N = Na for the operation mode a, the rotation speed N = Nb for the operation mode b, and the rotation speed N = Nc for the operation mode c is previously provided. It is stored in the storage device 100b. In step S6-3, the controller 100 selects the rotation speeds N of the

soot blowers

30 and 40 according to the operation mode, and controls the rotation speed of the motor 38.

According to this fourth embodiment, since the rotation speeds of the

soot blowers

30 and 40 can be adjusted, it is possible to finely suppress changes in the steam temperature of the heat transfer tube 6 according to the operation mode.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention, and all the technical matters included in the technical idea described in the claims are all. It is the subject of the present invention. Although the above-described embodiment shows a suitable example, those skilled in the art can realize various alternative examples, modifications, modifications or improvements from the contents disclosed in the present specification. These are included in the technical scope described in the appended claims.

In the embodiments described above, to calculate the time interval T _int2 soot blowers 30, 40 by integrating the difference between the steam inlet temperature and the steam outlet temperature of the heat transfer tube 6. This is because the steam inlet temperature and the steam outlet temperature of the heat transfer tube 6 are constantly fluctuating during the operation of the boiler 1, but both the steam inlet temperature and the steam outlet temperature of the heat transfer tube 6 are relatively stable. _{In the operating state, the interval time Tint2} may be calculated by integrating the difference only in the steam outlet temperature of the heat transfer tube 6.

Further, in the above embodiments, to calculate the time interval T _int2 using an integrated value ShigumadT, and controls the operation of the

sootblowers

30 and 40 calculates the interval time T _int2 each time to calculate a temperature change value dT Is also good.

Further, in the above-described embodiment, _{after the process of determining the interval time Tint2} (step S6), the process of selecting the spray vapor pressure P of the sootblower (step S6-2) and the process of determining the rotation speed N of the sootblower (step S6-2). Both steps S6-3) may be performed.

In the above embodiment has described the method of calculating the interval time of the soot blowers 30 installed in the heat exchanger T _int2, when calculating the interval time T _int2 soot blower 40 installed in the furnace wall 11, the furnace The temperature difference between the inlet and outlet of the cooling water of the wall 11 may be integrated.

1 Boiler 2 Fire furnace 3 Cage part 4 Secondary side wall 6 Heat transfer tube 10 Economizer 13 Primary superheater 14 Secondary superheater 15 Secondary superheater 16 Primary reheater 17 Secondary reheater 20a to 20i Temperature sensor (inlet temperature sensor) , Outlet temperature sensor)
30, 40 Soot blower 31 Soot blower tube 32

Nozzle block

33, 34 Spray hole 35 Spray steam supply line 36 Pressure sensor 37 Steam pressure control valve 38 Motor 39 Inverter 50 Monitor 100 Controller

Claims

A soot blower that injects steam onto the surface of a heat transfer tube provided in a boiler, an inlet temperature sensor that detects the steam inlet temperature of the heat transfer tube, an outlet temperature sensor that detects the steam outlet temperature of the heat transfer tube, and the inlet. In a steam blower control system comprising a temperature sensor and a controller that controls the operation of the steam blower based on each detection signal input from the outlet temperature sensor.
The controller
The first temperature difference, which is the difference between the steam inlet temperature and the steam outlet temperature at the first time point during the operation of the soot blower, and the steam inlet temperature and the steam at the second time point during the operation of the soot blower. The feature is that the temperature change value, which is the difference from the second temperature difference, which is the difference from the outlet temperature, is obtained, and the operation interval of the soot blower is determined so that the temperature change value is within the range of the target value. Control system of the soot blower.
In the control system of the soot blower according to claim 1,
The controller is characterized in that the temperature change value is integrated over a predetermined period to obtain an integrated value, and the operation interval of the soot blower is determined so that the integrated value is within the range of the target value. Soot blower control system.
In the control system of the soot blower according to claim 2.
A plurality of the soot blowers are provided,
The controller is a control system for a soot blower, characterized in that an operation interval of the soot blower is determined for each soot blower, and a plurality of the soot blowers are independently controlled according to the operation interval.
In the control system of the soot blower according to any one of claims 1 to 3,
A plurality of the target values are set in advance in association with the operation mode of the boiler.
The controller is a control system for a soot blower, which determines an operation interval of the soot blower based on the target value corresponding to the operation mode input from the outside.
In the control system of the soot blower according to any one of claims 1 to 3,
A plurality of spray steam pressures of the soot blower are set in advance in association with the operation mode of the boiler.
The controller is a control system for a soot blower, characterized in that the spray steam pressure of the soot blower is determined according to the operation mode input from the outside.
In the control system of the soot blower according to any one of claims 1 to 3,
A plurality of rotation speeds of the soot blower are set in advance in association with the operation mode of the boiler.
The controller is a control system for a soot blower, characterized in that the rotation speed of the soot blower is determined according to the operation mode input from the outside.
In the control system of the soot blower according to claim 2 or 3.
Further equipped with a monitor connected to the controller and displaying temperature information of the heat transfer tube,
The controller is a control system for a soot blower, characterized in that the monitor displays the integrated value so as to correspond to the arrangement of the soot blower.
In the control system of the soot blower according to claim 7.
The controller is characterized in that it stores the fuel information of the boiler input from the outside in association with the fuel information of the boiler, and displays the integrated value on the monitor for each type of fuel charged into the boiler. Control system.