Adhesion removal system and adhesion removal method

Abstract

To provide a deposit removal system that can reduce the number of times of maintenance of a pressure wave type soot blower while keeping heat transfer performance of a heat exchanger.SOLUTION: A deposit removal system 100 removes deposits attached to a heat transfer surface of a heat exchanger for recovering heat from exhaust gas generated in association with combustion of a combusted substance, by using pressure waves generated by combustion of combustion gas with which a combustion container 83 of a soot blower 80 is filled, and comprises: a reference value setting unit 301 for setting a reference value of heat transfer performance of the heat exchanger; an evaluation value calculation unit 302 for calculating an evaluation value of the heat transfer performance of the heat exchanger; and filling pressure adjustment means (82, 110, 303, 304, and 305) for adjusting a filling pressure of the combustion gas. When a difference between the reference value and the evaluation value becomes equal to or larger than a predetermined value, the filling pressure adjustment means (82, 110, 303, 304, and 305) increase the filling pressure of the combustion gas.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a deposit removal system and a deposit removal method for removing deposits adhering to a heat transfer surface of a heat exchanger that recovers heat from exhaust gas generated during combustion of a combustible material by a pressure wave generated by combustion of combustion gas filled in a pressure wave type soot blower.

Background Art

[0002] In recent years, it has become important to improve the power generation amount in waste combustion treatment facilities etc. equipped with power generation facilities. Power generation in waste combustion treatment facilities etc. is performed by recovering heat in a boiler from high-temperature exhaust gas generated during combustion of waste in a combustion furnace, generating steam at a predetermined temperature and pressure, and introducing it into a steam turbine generator.

[0003] A boiler has a radiation chamber and a convective heat transfer chamber. In the radiation chamber, radiation heat transfer tubes are arranged as a radiation heat transfer surface, and in the convective heat transfer chamber, for example, a superheater is arranged as a convective heat transfer surface. The superheater is configured by arranging a plurality of rows of heat transfer tube groups (superheater tubes) in which a plurality of heat transfer tubes (superheater tubes) are arranged in the horizontal direction in the height direction.

[0004] The exhaust gas from the combustion furnace contains dust (dust) containing corrosive components, heavy metals, etc. For this reason, as the operation progresses, dust gradually adheres and accumulates on the radiation heat transfer surface and the convective heat transfer surface of the boiler, causing problems such as a decrease in heat transfer performance, blockage of the gas flow path, and corrosion of the heat transfer tubes, and it may become difficult to continue normal operation.

[0005] To prevent such problems, a soot blower as a dust removal device is installed in the boiler, and the soot blower is started (operated) at predetermined time intervals (constant cycle) to remove the dust adhering to the heat transfer surface of the boiler. However, when the amount of dust deposited on the heat transfer surface is small, even if the soot blower is operated, the amount of dust removed is small, so the dust removal effect with respect to the cost required for the operation of the soot blower is low. On the other hand, when the amount of dust deposited on the heat transfer surface is large, the dust cannot be sufficiently removed by operating the soot blower at regular intervals, and the dust remaining on the heat transfer surface without being removed may solidify by the next operation of the soot blower, making it difficult to remove the dust by the soot blower.

[0006] Therefore, an adhesion removal system has been proposed to appropriately remove the dust adhering to the heat transfer surface using a soot blower (see, for example, Patent Document 1).

[0007] Patent Document 1 discloses an adhesion removal system in which the soot blower is operated once at a predetermined interval when the heat transfer rate of the boiler is equal to or higher than a predetermined value, an adhesion ash determination process is executed when the heat transfer rate is lower than the predetermined value, and the soot blower is continuously operated according to the result.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] In the deposit removal system disclosed in Patent Document 1, the single operation and continuous operation of the soot blower are properly used based on the heat transfer rate. When the heat transfer rate is less than a predetermined value, an attached ash determination process is executed, and it is determined appropriately whether to continuously operate the soot blower. Therefore, it is possible to avoid the continuous operation of the soot blower being performed unnecessarily, which is economical, and it is possible to appropriately perform dust removal, so that the heat transfer performance of a heat exchanger such as a superheater can be maintained. However, if the heat transfer rate is less than a predetermined value and a predetermined condition is satisfied, the continuous operation of the soot blower will be performed, and the number of operations of the soot blower itself will increase.

[0010] In recent years, in a pressure wave type soot blower introduced into the market, the maintenance frequency depends on the number of operations of the soot blower. For this reason, in the deposit removal system of Patent Document 1, the maintenance cost will increase.

[0011] The present invention has been made in view of the above problems, and an object thereof is to provide a deposit removal system and a deposit removal method capable of reducing the maintenance frequency of a pressure wave type soot blower while maintaining the heat transfer performance of a heat exchanger.

Means for Solving the Problems

[0012] A characteristic configuration of the deposit removal system according to the present invention for solving the above problems is a deposit removal system that removes deposits adhering to the heat transfer surface of a heat exchanger that recovers heat from exhaust gas generated by the combustion of a material to be burned by a pressure wave generated by the combustion of combustion gas filled in a pressure wave type soot blower, reference value setting means for setting a reference value of the heat transfer performance of the heat exchanger, evaluation value calculation means for calculating an evaluation value of the heat transfer performance of the heat exchanger, and filling pressure adjustment means for adjusting the filling pressure of the combustion gas, wherein when the difference between the reference value and the evaluation value becomes a predetermined value or more, the filling pressure adjustment means increases the filling pressure of the combustion gas.

[0013] According to the deposit removal system of this configuration, a reference value of the heat transfer performance of the heat exchanger (a standard value required as the heat transfer performance of the heat exchanger) is set by the reference value setting means. Further, an evaluation value of the heat transfer performance of the heat exchanger (a numerical value obtained by quantifying the evaluation result of the current heat transfer performance of the heat exchanger) is calculated by the evaluation value calculation means. When the difference between the set reference value and the calculated evaluation value of the heat transfer performance becomes a predetermined value or more, for example, it is predicted that deposits are excessively adhered and deposited on the heat transfer surface of the heat exchanger, or the deposits are firmly adhered and deposited. Therefore, the filling pressure of the combustion gas filled in the pressure wave soot blower is increased by the filling pressure adjusting means, and the power of the pressure wave generated by the combustion of the combustion gas is increased. As a result, the deposits can be sufficiently removed without relying on the continuous operation of the soot blower as in the prior art. Thus, the heat transfer performance can be restored at an early stage, and the number of operations of the pressure wave soot blower can be reduced. Therefore, while maintaining the heat transfer performance of the heat exchanger, the number of maintenance of the pressure wave soot blower can be reduced.

[0014] In the deposit removal system according to the present invention, it is preferable that the filling pressure adjusting means varies the filling pressure in accordance with the variation in the difference between the reference value and the evaluation value.

[0015] According to the deposit removal system of this configuration, since the filling pressure adjusting means varies the filling pressure in accordance with the variation in the difference between the set reference value and the calculated evaluation value, the power of the pressure wave can be appropriately increased without excess or deficiency, and the balance between the dust removal effect and the cost required for the operation of the pressure wave soot blower can be improved.

[0016] In the deposit removal system according to the present invention, it is preferable that the heat transfer performance is a performance determined based on the relationship between the flow rate of the exhaust gas and the heat exchange amount of the heat exchanger.

[0017] According to the deposit removal system of this configuration, since the heat transfer performance of the heat exchanger is determined based on the relationship between the exhaust gas flow rate and the heat exchange amount of the heat exchanger, the reference value of the heat transfer performance can be appropriately set, and the evaluation value of the heat transfer performance can be appropriately calculated.

[0018] In the deposit removal system according to the present invention, Preferably, the heat transfer performance is a performance determined based on the relationship between the flow rate of the exhaust gas and the temperature difference of the exhaust gas before and after heat recovery in the heat exchanger.

[0019] According to the deposit removal system of this configuration, since the heat transfer performance of the heat exchanger is determined based on the relationship between the exhaust gas flow rate and the temperature difference of the exhaust gas before and after heat recovery in the heat exchanger, the reference value of the heat transfer performance can be appropriately set, and the evaluation value of the heat transfer performance can be appropriately calculated.

[0020] In the deposit removal system according to the present invention, The heat exchanger is configured to superheat steam by recovering heat from the exhaust gas, Preferably, the heat transfer performance is a performance determined based on the relationship between the flow rate of the exhaust gas and the temperature difference between the steam inlet and outlet of the heat exchanger.

[0021] According to the deposit removal system of this configuration, since the heat transfer performance of the heat exchanger is determined based on the relationship between the exhaust gas flow rate and the temperature difference between the steam inlet and outlet of the heat exchanger, the reference value of the heat transfer performance can be appropriately set, and the evaluation value of the heat transfer performance can be appropriately calculated.

[0022] In the deposit removal system according to the present invention, Preferably, the heat transfer performance is a performance determined based on the relationship between the flow rate of the exhaust gas and the heat transfer rate of the heat exchanger.

[0023] According to the deposit removal system of this configuration, since the heat transfer performance of the heat exchanger is determined based on the relationship between the flow rate of the exhaust gas and the heat transfer coefficient of the heat exchanger, the reference value of the heat transfer performance can be appropriately set, and the evaluation value of the heat transfer performance can be appropriately calculated.

[0024] In the deposit removal system according to the present invention, Preferably, the heat transfer performance is a performance determined based on the relationship between the set value of the evaporation amount of the boiler including the heat exchanger and the heat exchange amount of the heat exchanger.

[0025] According to the deposit removal system of this configuration, since the heat transfer performance of the heat exchanger is determined based on the relationship between the set value of the evaporation amount of the boiler including the heat exchanger and the heat exchange amount of the heat exchanger, the reference value of the heat transfer performance can be appropriately set, and the evaluation value of the heat transfer performance can be appropriately calculated.

[0026] In the deposit removal system according to the present invention, Preferably, the heat transfer performance is a performance determined based on the relationship between the input amount of the material to be burned and the heat exchange amount of the heat exchanger.

[0027] According to the deposit removal system of this configuration, since the heat transfer performance is determined based on the relationship between the input amount of the material to be burned and the heat exchange amount of the heat exchanger, the reference value of the heat transfer performance can be appropriately set, and the evaluation value of the heat transfer performance can be appropriately calculated.

[0028] Next, the characteristic configuration of the deposit removal method according to the present invention for solving the above problems is A deposit removal method for removing deposits adhering to the heat transfer surface of a heat exchanger that recovers heat from the exhaust gas generated by the combustion of the material to be burned by a pressure wave generated by the combustion of the combustion gas filled in a pressure wave type soot blower, A reference value setting step of setting a reference value of the heat transfer performance of the heat exchanger, An evaluation value calculation step of calculating an evaluation value of the heat transfer performance of the heat exchanger, A filling pressure adjustment step of adjusting the filling pressure of the combustion gas; including When the difference between the reference value and the evaluation value becomes a predetermined value or more, in the filling pressure adjustment step, the filling pressure of the combustion gas is increased.

[0029] According to the deposit removal method of this configuration, in the reference value setting step, a reference value of the heat transfer performance of the heat exchanger is set. Further, in the evaluation value calculation step, an evaluation value of the heat transfer performance of the heat exchanger is calculated. When the difference between the set reference value and the calculated evaluation value of the heat transfer performance becomes a predetermined value or more, for example, it is predicted that deposits are excessively attached and deposited on the heat transfer surface of the heat exchanger, or the deposits are firmly attached and deposited. Therefore, in the filling pressure adjustment step, the filling pressure of the combustion gas filled in the pressure wave type soot blower is increased to increase the power of the pressure wave generated by the combustion of the combustion gas. As a result, deposits can be sufficiently removed without relying on the continuous operation of the soot blower as in the prior art. In this way, the heat transfer performance can be restored at an early stage, and the number of operations of the pressure wave type soot blower can be reduced. Therefore, it is possible to reduce the maintenance frequency of the pressure wave type soot blower while maintaining the heat transfer performance of the heat exchanger.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0031] Hereinafter, the present invention will be described with reference to the drawings. In the following embodiments, a boiler installed in parallel with a combustion furnace of a waste combustion treatment facility, an adhesion removal system applied to a economizer, and an adhesion removal method will be described as examples. However, the present invention is not intended to be limited to the configurations described in the following embodiments and the drawings.

[0032] <Overall Configuration of Waste Combustion Treatment Facility> FIG. 1 is a schematic diagram showing a schematic configuration of a combustion treatment facility 1 to which an adhesion removal system 100 (see FIG. 2) according to an embodiment of the present invention is applied. As shown in FIG. 1, the combustion treatment facility 1 mainly includes a combustible material receiving section 2, a feeding device 3, a combustion furnace 4, a boiler 5, and an economizer 6. In this combustion treatment facility 1, a combustible material (for example, waste such as municipal waste) is introduced into the combustible material receiving section 2 by a crane (garbage crane) 10 having a weighing function. The combustible material received by the combustible material receiving section 2 is supplied into the combustion furnace 4 by the feeding device 3 and burned. The exhaust gas generated by the combustion in the combustion furnace 4 is sequentially introduced into the boiler 5 and the economizer 6 by the suction action of a suction fan (not shown) and heat is recovered. Thereafter, the exhaust gas is cooled in a desuperheater (not shown), introduced into a bag filter (not shown) together with a neutralizing agent or the like, and after acidic gas components and dust (dirt) are removed in the bag filter, it is introduced into a denitration device (not shown), and after denitration treatment, it is discharged to the outside through a chimney (not shown). Note that a power generation facility (not shown) is installed in parallel with the combustion treatment facility 1, and power generation is performed by introducing the steam generated in the boiler 5 into the power generation facility.

[0033] The feeding device 3 includes a pusher 7 that reciprocates along a flat floor surface below the combustible material receiving section 2 to push out the combustible material, a drive mechanism 8 that reciprocally drives the pusher 7, and a control panel 9 that controls the drive mechanism 8. The drive mechanism 8 is configured to be controlled based on a control signal from the control panel 9 so that the supply amount of the combustible material into the combustion furnace 4 is controlled.

[0034] <Boiler> The boiler 5 includes a first radiant chamber 11, a second radiant chamber 12, and a convective heat transfer chamber 13, which are partitioned in order from the upstream side to the downstream side in the exhaust gas flow direction.

[0035] The first radiant chamber 11 extends vertically so as to be connected to the combustion chamber of the combustion furnace 4. The first radiant chamber 11 and the second radiant chamber 12 are connected via a first turning portion 15. The second radiant chamber 12 extends vertically so as to be adjacent to the first radiant chamber 11. The second radiant chamber 12 and the convective heat transfer chamber 13 are connected via a second turning portion 16. The convective heat transfer chamber 13 extends vertically so as to be adjacent to the second radiant chamber 12.

[0036] In the boiler 5, the exhaust gas introduced from the combustion furnace 4 flows from below to above in the first radiant chamber 11, further flows from above to below in the second radiant chamber 12 via the first turning portion 15, and then flows from below to above in the convective heat transfer chamber 13 via the second turning portion 16.

[0037] A number of radiant heat transfer tubes (not shown) that constitute a radiant heat transfer surface for generating steam by receiving radiant heat from the exhaust gas are arranged in the first radiant chamber 11 and the second radiant chamber 12.

[0038] In the convection heat transfer chamber 13, a screen tube 20 and a plurality of superheaters 21, 22, 23 each consisting of heat exchange parts of the same type are arranged. In this example, in the convection heat transfer chamber 13, the screen tube 20 is arranged at the most upstream part of the exhaust gas flow, and downstream of the screen tube 20, the tertiary superheater 21, the secondary superheater 22, and the primary superheater 23 are arranged in order from the upstream side to the downstream side in the exhaust gas flow direction with a predetermined interval therebetween. The screen tube 20 is formed by arranging heat transfer tubes in a flag shape, and is configured to cool the exhaust gas introduced into the convection heat transfer chamber 13. The superheaters 21, 22, 23 include a group of heat transfer tubes in which a plurality of horizontally arranged heat transfer tubes are provided in multiple stages in the height direction, and the heat transfer tubes constitute a convection heat transfer surface, and are configured to generate and further superheat steam by heat exchange with the exhaust gas. Here, an example of arranging the screen tube 20 and the plurality of superheaters 21, 22, 23 in the convection heat transfer chamber 13 is shown, but it is not limited thereto. In addition to the screen tube 20 and the superheaters 21, 22, 23, an evaporation tube, an economizer, etc. may be appropriately arranged in the convection heat transfer chamber 13.

[0039] <Economizer> The boiler 5 and the economizer 6 are connected via the third turning part 17. The economizer 6 includes a convection heat transfer chamber 14 extending vertically so as to be adjacent to the convection heat transfer chamber 13. In the convection heat transfer chamber 14, a plurality of economizer parts 31, 32, 33 are arranged with a predetermined interval therebetween. In this example, the first economizer part 31, the second economizer part 32, and the third economizer part 33 are arranged in order from the upstream side to the downstream side in the exhaust gas flow direction. The economizer parts 31, 32, 33 include a group of economizer water tubes in which a plurality of horizontally arranged economizer water tubes are provided in multiple stages in the height direction.

[0040] [Exhaust gas thermometer] An exhaust gas thermometer 41 for measuring the temperature of the exhaust gas flowing from the first radiation chamber 11 to the second radiation chamber 12 is arranged in the first turning part 15. An exhaust gas thermometer 42 for measuring the temperature of the exhaust gas flowing from the second radiation chamber 12 to the convection heat transfer chamber 13 is arranged in the second turning part 16.

[0041] In the convection heat transfer chamber 13, an exhaust gas thermometer 43 for measuring the temperature of the exhaust gas flowing through the screen tube 20 and into the tertiary superheater 21 is disposed. In the convection heat transfer chamber 13, an exhaust gas thermometer 44 for measuring the temperature of the exhaust gas flowing through the tertiary superheater 21 and into the secondary superheater 22 is disposed. In the convection heat transfer chamber 13, an exhaust gas thermometer 45 for measuring the temperature of the exhaust gas flowing through the secondary superheater 22 and into the primary superheater 23 is disposed. In the convection heat transfer chamber 13, an exhaust gas thermometer 46 for measuring the temperature of the exhaust gas flowing through the primary superheater 23 and into the third turning section 17 is disposed.

[0042] In the convection heat transfer chamber 14, an exhaust gas thermometer 47 for measuring the temperature of the exhaust gas flowing from the third turning section 17 to the first economizer section 31 is disposed. In the convection heat transfer chamber 14, an exhaust gas thermometer 48 for measuring the temperature of the exhaust gas flowing through the third economizer section 33 and into the bottom of the fuel saver 6 is disposed.

[0043] [Steam flow meter] In the tertiary superheater 21, the secondary superheater 22, and the primary superheater 23, a steam flow meter 51, a steam flow meter 52, and a steam flow meter 53 for measuring the flow rate of steam are respectively attached.

[0044] [Steam thermometer] In the tertiary superheater 21, a steam thermometer 61a for measuring the steam temperature on the inlet side and a steam thermometer 61b for measuring the steam temperature on the outlet side are attached. Similarly, in the secondary superheater 22, a steam thermometer 62a for measuring the steam temperature on the inlet side and a steam thermometer 62b for measuring the steam temperature on the outlet side are attached. Similarly, in the primary superheater 23, a steam thermometer 63a for measuring the steam temperature on the inlet side and a steam thermometer 63b for measuring the steam temperature on the outlet side are attached.

[0045] [Feed water thermometer, feed water flow meter] The fuel-saving device 6 is equipped with a feed water temperature gauge 71 for measuring the feed water temperature on the inlet side and a feed water temperature gauge 72 for measuring the feed water temperature on the outlet side. The first economizer section 31, the second economizer section 32, and the third economizer section 33 are respectively equipped with a feed water temperature gauge 54, a feed water temperature gauge 55, and a feed water temperature gauge 56 for measuring the feed water temperature. The fuel-saving device 6 is equipped with a feed water flow meter 75 for measuring the feed water flow rate. The first economizer section 31, the second economizer section 32, and the third economizer section 33 are respectively equipped with a feed water flow meter 57, a feed water flow meter 58, and a feed water flow meter 59 for measuring the feed water flow rate.

[0046] <Deposit removal system> Figure 2 is a schematic diagram showing the schematic configuration of the deposit removal system 100 according to an embodiment of the present invention. As shown in Figure 2, the deposit removal system 100 includes a pressure wave type soot blower (hereinafter simply abbreviated as "soot blower") 80, a control panel 110 for controlling the operation of the soot blower 80, and a controller 120 communicably connected to the control panel 110.

[0047] <Soot blower> As the soot blower 80, for example, the deposit removal device disclosed in International Publication No. 2020 / 225984 is used. As shown in Figure 1, the soot blower 80 includes a soot blower 80a disposed in the boiler 5 such that the pressure wave discharge port is located at the intermediate position in the vertical direction in the second radiation chamber 12, a soot blower 80b disposed in the boiler 5 such that the pressure wave discharge port is located between the screen tube 20 and the tertiary superheater 21 in the convective heat transfer chamber 13, and a soot blower 80c disposed in the fuel-saving device 6 such that the pressure wave discharge port is located between the first economizer section 31 and the second economizer section 32 in the convective heat transfer chamber 14.

[0048] As shown in Figure 2, the soot blower 80 includes a soot blower main body 81 and a gas supply means 82.

[0049] The suit blower main body 81 includes a combustion container 83 having an opening 83a, a strip-shaped sealing body 84 that closes the opening 83a, a switching mechanism 85 that switches between a pressed state and a non-pressed state of the sealing body 84 with respect to the opening 83a, and a sealing body supply mechanism 86 that supplies the sealing body 84 to the opening 83a when the sealing body 84 is in the non-pressed state with respect to the opening 83a.

[0050] The gas supply means 82 supplies combustion gas such as combustible gas and oxidant gas necessary for combustion to the combustion container 83, and mainly includes a main supply pipeline 90, a combustible gas supply pipeline 91, and an oxidant gas supply pipeline 92. One end side of the main supply pipeline 90 is connected to the end wall portion of the combustion container 83 so that gas can be supplied into the combustion container 83. A combustible gas supply source 93 is connected to the other end side of the main supply pipeline 90 via the combustible gas supply pipeline 91, and an oxidant gas supply source 94 is connected via the oxidant gas supply pipeline 92. In this way, the combustible gas from the combustible gas supply source 93 can be supplied into the combustion container 83 via the combustible gas supply pipeline 91 and the main supply pipeline 90, and the oxidant gas from the oxidant gas supply source 94 can be supplied via the oxidant gas supply pipeline 92 and the main supply pipeline 90. Here, examples of the combustible gas include methane, hydrogen, etc. (methane in this example). On the other hand, examples of the oxidant gas include oxygen, air, etc. (oxygen in this example).

[0051] In the middle of the main supply pipeline 90, a main supply valve 95 is installed. On the upstream side of the gas flow of the main supply valve 95 in the main supply pipeline 90, a pressure gauge 96 for measuring the internal pressure of the combustion container 83 is connected. In the combustible gas supply pipeline 91, a combustible gas supply valve 97 is installed. In the oxidant gas supply pipeline 92, an oxidant gas supply valve 98 is installed. Then, based on the measurement signal of the pressure gauge 96, at a predetermined filling pressure (Ps or Pv described later) of the combustion gas filled in the combustion container 83, the opening degree, opening time, or number of opening and closing of each of the main supply valve 95, the combustible gas supply valve 97, and the oxidant gas supply valve 98 is adjusted so that the combustible gas and the oxidant gas have a predetermined mixing ratio. Thereby, the combustible gas and the oxidant gas are mixed at a predetermined mixing ratio inside the combustion container 83 at a predetermined filling pressure of the combustion gas.

[0052] A glow plug 99 as an electric ignition means is attached to the end wall portion of the combustion container 83. By energizing the glow plug 99, the combustion gas (mixed gas of methane gas and oxygen gas) inside the combustion container 83 is ignited, and the flame rapidly expands while propagating, thereby generating a pressure wave. Note that the electric ignition means is not limited to the glow plug 99, and an ignition plug that causes an explosion ignition of the combustion gas by an electric spark may be used.

[0053] In the soot blower 80, the combustion container 83 is filled with combustion gas, and the filled combustion gas is burned by ignition with the glow plug 99 to increase the pressure inside the combustion container 83, thereby breaking the sealing body 84 to generate a pressure wave, and the generated pressure wave is discharged from the pressure wave discharge port 87 to remove the deposits (dust) adhering to the heat transfer tube. It is configured to be able to perform an attachment removal operation (pressure wave driving operation). Further, in the soot blower 80, it is configured to be able to perform the attachment removal operation periodically once at regular intervals by the cooperation of the switching mechanism 85 and the sealing body supply mechanism 86.

[0054] <Control panel> The control panel 110 is mainly composed of a computer equipped with a CPU, memory, storage, I / O ports, peripheral devices, etc. The control panel 110 controls the operation of the soot blower 80, for example, the switching operation between the pressed state and the non-pressed state by the switching mechanism 85, the sealing body supply operation by the sealing body supply mechanism 86, the filling operation of the combustion gas into the combustion container 83 by the gas supply means 82, the ignition operation of the glow plug 99 for the filled combustion gas, etc.

[0055] <Controller> The controller 120 is mainly composed of a computer equipped with a CPU, memory, storage, I / O ports, peripheral devices, etc. When the CPU reads and executes a predetermined program stored in the memory, the functions of the reference value setting unit 301, the evaluation value calculation unit 302, the filling pressure calculation unit 303, the filling pressure target value setting unit 304, and the operation control unit 305 are exerted. Examples of the controller 120 include a distributed control system (DCS), a programmable logic controller, a server, a workstation, and other computer devices. The respective functions of the reference value setting unit 301, the evaluation value calculation unit 302, the filling pressure calculation unit 303, the filling pressure target value setting unit 304, and the operation control unit 305 will be described in conjunction with the description of the flowchart (see FIG. 3) showing the operation control procedure of the soot blower 80. Note that the reference value setting unit 301 corresponds to the "reference value setting means" of the present invention. The evaluation value calculation unit 302 corresponds to the "evaluation value calculation means" of the present invention. The configuration including the gas supply means 82, the control panel 110, the filling pressure calculation unit 303, the filling pressure target value setting unit 304, and the operation control unit 305 corresponds to the "filling pressure adjustment means" of the present invention.

[0056] FIG. 3 is a flowchart showing the operation control procedure of the soot blower 80 implemented in the dust removal method according to an embodiment of the present invention. In FIG. 3, the symbol "S" represents a step. At the start stage of the flowchart in FIG. 3, it is assumed that the target value of the filling pressure of the combustion gas for the combustion container 83 is set to the initial set pressure Ps.

[0057] In the following, as an example, the dust removal operation for the radiation heat transfer tubes in the second radiation chamber 12, the screen tubes 20 in the convection heat transfer chamber 13, and the superheaters 21, 22, and 23 using the soot blowers 80a and 80b arranged in the boiler 5 will be described with reference to the flowchart of FIG. 3. Here, the radiation heat transfer tubes in the second radiation chamber 12, the screen tubes 20 in the convection heat transfer chamber 13, and the superheaters 21, 22, and 23 are all heat exchangers, and these are collectively referred to as the "heat exchanger 200".

[0058] <S1: Reference value setting step> In step S1 in the flowchart shown in FIG. 3, the reference value setting unit 301 (see FIG. 2) sets a heat transfer performance reference value line La as shown in FIG. 4 as the reference value for the heat transfer performance of the heat exchanger 200. Here, the reference value for the heat transfer performance of the heat exchanger 200 is a standard value required for the heat transfer performance of the heat exchanger 200, and is set based on data obtained from the relationship between the exhaust gas flow rate and the heat exchange amount as the heat transfer performance of the heat exchanger 200 in a state where no dust adheres to the heat transfer surface (outer surface of the heat transfer tube) of the heat exchanger 200.

[0059] FIG. 4 is a graph showing the relationship between the exhaust gas flow rate and the heat exchange amount related to the heat transfer performance of the heat exchanger 200. The heat transfer performance of the heat exchanger 200 is a performance determined based on the relationship between the exhaust gas flow rate and the heat exchange amount. In FIG. 4, the vertical axis indicates the heat exchange amount, and the horizontal axis indicates the exhaust gas flow rate. In FIG. 4, the heat transfer performance threshold line Lb shown below the heat transfer performance reference value line La is a line indicating a level where the heat exchange amount (evaluation value) is lower than the heat transfer performance reference value line La by a predetermined value.

[0060] <S2: Evaluation value calculation step> In step S2 in the flowchart shown in FIG. 3, the evaluation value calculation unit 302 (see FIG. 2) calculates the evaluation value of the heat transfer performance of the heat exchanger 200. That is, the current exhaust gas flow rate Mg from the combustion furnace 4 is calculated, and the current heat exchange amount Mq in the heat exchanger 200 is calculated.

[0061] [Calculation of exhaust gas flow rate] The evaluation value calculation unit 302 (see Figure 2) calculates the real-time exhaust gas flow rate Mg of the combustion furnace 4 using the economizer 6 provided in the exhaust gas flow path from the combustion furnace 4, based on the heat exchange amount Qe in the economizer 6, the inlet and outlet temperatures of the exhaust gas and feed water (Tgi, Tgo, Twi, Two), and the relationship between the exhaust gas flow rate Mg and the feed water flow rate Mw. The following equations (1) and (2) are used for the calculation. Qe[kJ / h] = Mg×Cpg×(Tgo - Tgi) = Mw×Cpw×(Two - Twi)+Qa ···(1) Mg[m 3 N / h] = (Mw×Cpw×(Two - Twi)+Qa) / Cpg / (Tgo - Tgi) ···(2) Here, Mw: Measured value of the feed water flow meter 75 Twi: Measured value of the feed water thermometer 71 Two: Measured value of the feed water thermometer 72 Cpw: Average specific heat at constant pressure of the feed water in the economizer 6 Tgi: Measured value of the exhaust gas thermometer 47 Tgo: Measured value of the exhaust gas thermometer 48 Cpg: Average specific heat at constant pressure of the exhaust gas in the economizer 6 Qa: Set value of the heat dissipation amount of the economizer 6

[0062] [Calculation of heat exchange amount] The evaluation value calculation unit 302 (see Figure 2) calculates the real-time heat exchange amount Qq in each of the superheaters 21 to 23 using the following equation (3) based on the steam flow rate and the steam inlet and outlet temperatures of each of the superheaters 21 to 23. QqN = MsN×(TsoN - TsiN) ···(3) Here, N: Natural number Ms1~Ms3: Measured values of the steam flow meters 51~53 Tsi1~Tsi3: Steam thermometers 61a~63a (inlet side) Tso1~Tso3: Steam thermometers 61b~63b (outlet side)

[0063] <S3~S5> The value of the heat exchange amount Mq with respect to the current exhaust gas flow rate Mg is an evaluation value indicating the current heat transfer performance of the heat exchanger 200. In step S3, it is determined whether the difference between the set reference value and the current evaluation value of the heat transfer performance of the heat exchanger 200 is equal to or greater than a predetermined value (S3: comparison and determination step). In the graph of FIG. 4, for example, when the current exhaust gas flow rate Mg is Mgx on the horizontal axis and the current heat exchange amount Mq is Mqa on the vertical axis, the point A on the graph specified by Mgx and Mqa is located below the heat transfer performance threshold line Lb. Therefore, it is determined that the difference between the set reference value and the current evaluation value of the heat transfer performance of the heat exchanger 200 is equal to or greater than a predetermined value (in step S, "YES"). In this case, the filling pressure calculation unit 303 (see FIG. 2) calculates a filling pressure Pv corresponding to the difference (ΔMq) between the reference value Mqx of the heat transfer performance and the evaluation value Mqa of the heat transfer performance when the current exhaust gas flow rate Mg is Mgx (S4: filling pressure calculation step). Then, the filling pressure target value setting unit 304 (see FIG. 2) sets the filling pressure Pv calculated in step S4 as the target value of the filling pressure P to be reached (S5: filling pressure setting step).

[0064] On the other hand, in the graph of FIG. 4, for example, when the current exhaust gas flow rate Mg is Mgx on the horizontal axis and the current heat exchange amount Mq is Mqb on the vertical axis, the point B in the exhaust gas flow rate - heat exchange amount coordinate system specified by Mgx and Mqb is located between the heat transfer performance reference value line La and the heat transfer performance threshold line Lb. Therefore, it is determined that the difference between the set reference value and the current evaluation value of the heat transfer performance of the heat exchanger 200 is not equal to or greater than a predetermined value (in step S, "NO"). In this case, the filling pressure target value setting unit 304 (see FIG. 2) sets the initial set pressure Ps as the target value of the filling pressure P to be reached (S6: filling pressure setting step).

[0065] <S7: Operation command step> In step S7, the operation control unit 305 (see FIG. 2) transmits an operation command signal including a command signal for setting the target value of the filling pressure P to the filling pressure Pv or the initial set pressure Ps to the control panel 110.

[0066] The control panel 110 controls the soot blower 80 so that the soot blower 80 performs a dust removal operation using the operation command signal from the operation control unit 305 as a trigger. That is, as shown in FIG. 2, the opening 83a of the combustion container 83 is sealed with a sealing body 84, the combustion gas is filled into the combustion container 83 by the gas supply means 82 so that the filling pressure becomes Pv or Ps, the combustion gas is ignited and burned by energizing the glow plug 99, and the pressure in the combustion container 83 is increased to break the sealing body 84 and generate a pressure wave. As a result, the pressure wave is discharged from the pressure wave discharge port 87 into the second radiation chamber 12 and the convection heat transfer chamber 13 of the boiler 5, and the dust adhering and depositing on the radiation heat transfer tubes constituting the radiation heat transfer surface of the second radiation chamber 12 is removed by the wind pressure and vibration caused by the pressure wave, and the dust adhering and depositing on the screen tube 20 and the heat transfer tubes of the superheaters 21 to 23 in the convection heat transfer chamber 13 is removed. In this way, the dust adhering to the heat transfer tubes can be removed over a wide range.

[0067] Note that the process including the filling pressure calculation step in step S4, the filling pressure setting step in step S5, and the operation command step in step S7 corresponds to the "filling pressure adjustment step" of the present invention.

[0068] In the flowchart of FIG. 3, when the evaluation value calculated in the evaluation value calculation step of the heat transfer performance in step S2 is equal to or less than a predetermined value than the reference value set in the reference value setting step of the heat transfer performance in step S1, that is, when the difference between the set reference value and the current evaluation value of the heat transfer performance of the heat exchanger 200 is equal to or greater than a predetermined value ("YES" in step S3), it is predicted that dust is excessively attached or deposited on the heat transfer surface of the heat exchanger 200, or the dust is firmly attached or deposited. Therefore, in the filling pressure adjustment step including a series of steps S4, S5, and S7, the filling pressure of the combustion gas filled in the combustion container 83 of the soot blowers 80a and 80b is increased to increase the power of the pressure wave generated by the combustion of the combustion gas. As a result, dust can be sufficiently removed without relying on the continuous operation of the conventional soot blower. In this way, the heat transfer performance can be restored at an early stage, and the number of operations of the soot blowers 80a and 80b can be reduced. Therefore, while maintaining the heat transfer performance of the heat exchanger 200, the maintenance frequency of the soot blowers 80a and 80b can be reduced.

[0069] In the filling pressure calculation step of step S4, the filling pressure Pv corresponding to the fluctuation of the difference (ΔMq: see FIG. 4) between the reference value Mqx of the heat transfer performance and the evaluation value Mqa of the heat transfer performance when the current exhaust gas flow rate Mg is Mgx is calculated by the filling pressure calculation unit 303 (see FIG. 2). Since the calculated filling pressure Pv is set as the target value of the filling pressure P to be reached by the filling pressure target value setting unit 304 (see FIG. 2) in the filling pressure setting step of step S5, the power of the pressure wave can be appropriately increased without excess or deficiency, and the balance between the dust removal effect and the cost required for the operation of the soot blowers 80a and 80b can be improved.

[0070] As described above, the deposit removal system and the deposit removal method of the present invention have been described based on one embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and the configuration can be appropriately changed without departing from the gist thereof.

[0071] (Alternative Embodiment 1) In the heat transfer performance determined based on the relationship between the exhaust gas flow rate and the heat exchange amount of the heat exchanger 200 in the above embodiment, instead of the heat exchange amount of the heat exchanger 200, it may be the temperature difference of the exhaust gas before and after heat recovery in the heat exchanger 200. That is, the heat transfer performance of the heat exchanger 200 may be determined based on the relationship between the flow rate of the exhaust gas flowing through the second radiation chamber 12 and the convection heat transfer chamber 13 and the difference in the measured values of the exhaust gas thermometers 41 and 46, which is the temperature difference of the exhaust gas before and after heat recovery in the heat exchanger 200.

[0072] (Alternative Embodiment 2) In the heat transfer performance determined based on the relationship between the exhaust gas flow rate and the heat exchange amount of the heat exchanger 200 in the above embodiment, instead of the heat exchange amount of the heat exchanger 200, it may be the temperature difference between the steam inlet and outlet of the heat exchanger 200. That is, the heat transfer performance of the heat exchanger 200 may be determined based on the relationship between the flow rate of the exhaust gas flowing through the second radiation chamber 12 and the convection heat transfer chamber 13 and the difference in the measured values of the steam thermometers 61a, 62a, 63a and the steam thermometers 61b, 62b, 63b, which is the temperature difference between the steam inlet and outlet of the heat exchanger 200.

[0073] (Alternative Embodiment 3) In the heat transfer performance determined based on the relationship between the exhaust gas flow rate and the heat exchange amount of the heat exchanger 200 in the above embodiment, instead of the heat exchange amount of the heat exchanger 200, it may be the heat transfer rate of the heat exchanger 200. That is, the heat transfer performance of the heat exchanger 200 may be determined based on the relationship between the flow rate of the exhaust gas flowing through the second radiation chamber 12 and the convection heat transfer chamber 13 and the heat transfer rate of the heat exchanger 200 obtained by the following formula (4).

[0074] [Number]

[0075] (Alternative Embodiment 4) In the heat transfer performance determined based on the relationship between the exhaust gas flow rate and the heat exchange amount of the heat exchanger 200 in the above embodiment, instead of the exhaust gas flow rate, it may be a set value of the evaporation amount of the boiler 5 including the heat exchanger 200. That is, the heat transfer performance of the heat exchanger 200 may be determined based on the relationship between the boiler evaporation amount obtained by the calculation method described below and the heat exchange amount of the heat exchanger 200. [Calculation of Boiler Evaporation Amount] The boiler evaporation amount can be obtained from the calorific value of the combustible material calculated based on the relationship between the calorific value of the combustible material and the boiler evaporation amount shown in the following formulas (5) and (6). (Calorific value of the combustible material) = (Calorific value of the combustible material) × (Input amount of the combustible material) = (Boiler evaporation amount × Steam enthalpy + Heat taken out - Heat taken in) ···(5) (Boiler evaporation amount) = (Calorific value of the combustible material - Heat taken out + Heat taken in) / (Steam enthalpy) ···(6) Here, the input amount of the combustible material is calculated, for example, by integrating the weight measurement values per hour based on the weight measurement value of the combustible material grasped by the crane 10 when the combustible material is input into the combustible material receiving part 2. Note that the input amount of the combustible material can also be calculated based on the supply rate of the combustible material (supply amount per unit time) determined by the reciprocating speed of the pusher 7 of the dust feeder 3, and can be calculated in real time based on the data from the control panel 9 that controls the drive mechanism 8 that reciprocally drives the pusher 7. Also, the steam enthalpy, heat taken out, and heat taken in can be calculated in real time based on the measured values of the exhaust gas thermometers 41 to 48, steam flow meters 51 to 53, steam thermometers 61a to 63a, steam thermometers 61b to 63b, feed water thermometers 71, 72, feed water flow meter 75, etc.

[0076] (Another Embodiment 5) In the heat transfer performance determined based on the relationship between the exhaust gas flow rate and the heat exchange amount of the heat exchanger 200 in the above-described embodiment, instead of the exhaust gas flow rate, the input amount of the material to be burned may be used. That is, as described above, for example, based on the relationship between the input amount of the material to be burned that can be calculated by integrating the weight measurement value of the material to be burned grasped by the crane 10 per hour or the data from the control panel 9 and the heat exchange amount, the heat transfer performance of the heat exchanger 200 may be determined.

[0077] In addition, when using the set value of the boiler evaporation amount or the input amount of the material to be burned instead of the exhaust gas flow rate as in the above-described Another Embodiment 4 or Another Embodiment 5, for the economizer 6 as well, a dust removal method similar to the dust removal method for the heat exchanger 200 in the above-described embodiment can be applied.

Industrial Applicability

[0078] The deposit removal system and the deposit removal method of the present invention can be used, for example, in applications for removing deposits such as dust adhering to the heat transfer surfaces of heat exchangers such as boilers, economizers (economizers), and air preheaters that recover heat from exhaust gases generated by the combustion of fossil fuels in thermal power generation facilities, steel mills, petroleum refining facilities, etc., exhaust gases generated by the combustion of waste in waste combustion facilities, and exhaust gases generated by the combustion of biomass fuels in biomass power generation facilities.

Explanation of Reference Numerals

[0079] 1 Combustion treatment facility 80 Soot blower (pressure wave type soot blower) 82 Gas supply means (filling pressure adjustment means) 100 Deposit removal system 110 Control panel (filling pressure adjustment means) 200 Heat exchanger 301 Reference value setting unit (reference value setting means) 302 Evaluation value calculation unit (evaluation value calculation means) 303 Filling pressure calculation unit (filling pressure adjustment means) 304 Filling pressure target value setting unit (filling pressure adjustment means) 305 Operation control unit (filling pressure adjustment means)

Claims

1. An adhesion removal system for removing deposits adhering to the heat transfer surface of a heat exchanger that recovers heat from the exhaust gas generated by the combustion of a combustible material by a pressure wave generated by the combustion of combustion gas filled in a pressure wave type soot blower, comprising: Reference value setting means for setting a heat transfer performance reference value line based on data obtained from the relationship between the flow rate of the exhaust gas and the heat exchange amount of the heat exchanger as the heat transfer performance of the heat exchanger in a state where no deposits adhere to the heat transfer surface, and setting a heat transfer performance threshold line indicating a low level of the heat exchange amount of the heat exchanger with respect to the heat transfer performance reference value line; Evaluation value calculation means for calculating a value of the current heat exchange amount of the heat exchanger with respect to the current flow rate of the exhaust gas as an evaluation value of the heat transfer performance of the heat exchanger; Filling pressure adjustment means for adjusting the filling pressure of the combustion gas; When the current heat exchange amount of the heat exchanger calculated by the evaluation value calculation means is lower than the heat transfer performance threshold line, the filling pressure adjustment means increases the filling pressure of the combustion gas. An adhesion removal system.

2. The adhesion removal system according to claim 1, wherein the filling pressure adjustment means varies the filling pressure in accordance with a variation in the difference between the heat transfer performance reference value line and the current heat exchange amount of the heat exchanger calculated by the evaluation value calculation means.

3. An adhesion removal method for removing deposits adhering to the heat transfer surface of a heat exchanger that recovers heat from the exhaust gas generated by the combustion of a combustible material by a pressure wave generated by the combustion of combustion gas filled in a pressure wave type soot blower, comprising: A reference value setting step of setting a heat transfer performance reference value line based on data obtained from the relationship between the flow rate of the exhaust gas and the heat exchange amount of the heat exchanger as the heat transfer performance of the heat exchanger in a state where no deposits adhere to the heat transfer surface, and setting a heat transfer performance threshold line indicating a low level of the heat exchange amount of the heat exchanger with respect to the heat transfer performance reference value line; An evaluation value calculation step of calculating a value of the current heat exchange amount of the heat exchanger with respect to the current flow rate of the exhaust gas as an evaluation value of the heat transfer performance of the heat exchanger; A filling pressure adjustment step of adjusting the filling pressure of the combustion gas; Including: When the current heat exchange amount of the heat exchanger calculated by the evaluation value calculation step is lower than the heat transfer performance threshold line, in the filling pressure adjustment step, the filling pressure of the combustion gas is increased. An adhesion removal method.

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