Boiler monitoring method and boiler monitoring device, boiler control method and boiler control device, fuel adjustment method and fuel adjustment device, and boiler

Abstract

According to the present invention, a method for monitoring an operation state of a boiler 1 comprises: an exhaust gas collection step S1 for collecting exhaust gas generated by combustion of fuel fed into a combustion furnace 2 of the boiler 1; and an estimation step S2 for estimating the contained amount of alkali metals and / or chlorine on the basis of the contained amount of fine salt particles in the exhaust gas having been collected in the exhaust gas collection step S1.

Description

[Technical Field]

[0001] The present invention relates to a boiler monitoring method and boiler monitoring device, a boiler control method and boiler control device, a fuel etc. adjustment method and fuel etc. adjustment device, and a boiler. [Background technology]

[0002] Various boiler systems have been proposed that generate steam using the heat of high-temperature exhaust gas obtained by burning fuel in a combustion furnace (furnace). In such boiler systems, problems such as poor flow within the combustion furnace, deposits (dust) on the boiler piping surface, and piping corrosion due to deposits can occur due to fluctuations in fuel properties and increases or decreases in the corrosive components in the fuel. To solve these problems, it is possible to measure the concentration of alkali metal components in the exhaust gas and take measures to reduce the concentration.

[0003] In recent years, a technique has been proposed in which alkali metal components contained in exhaust gas after passing through a boiler dust collector are made to emit light, and the light in a predetermined wavelength range is separated to determine the relative emission intensity, thereby measuring the concentration of the alkali metal components emitting light in that wavelength range (see, for example, Patent Document 1).It is said that the adoption of this technique makes it possible to measure the concentration of alkali metal components in exhaust gas with high accuracy. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3182913 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the measurement method using flame photometry described in Patent Document 1 measures the concentration of alkali metal components contained in the exhaust gas after it has been collected by a dust collector, and therefore has the problem of being unable to properly measure the concentration of fine salt particles (such as KCl) contained in the exhaust gas before it has been collected by the dust collector.Furthermore, the measurement method using flame photometry described in Patent Document 1 requires the formation of a plasma flame in the flue through which the combustion gas flows and the emission of light in the plasma flame, which introduces many technical uncertainties and may make measurement difficult.

[0006] The present invention has been made in consideration of the above circumstances, and aims to monitor the content of fine salt particles in boiler exhaust gas using a relatively simple method and to appropriately estimate the content of alkali metals and chlorine in fuel. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the boiler monitoring method of the present invention is a method for monitoring the operating state of a boiler, and includes an exhaust gas collection step of collecting exhaust gas generated by the combustion of fuel fed into the boiler's combustion furnace, and an estimation step of estimating the content of alkali metals and / or chlorine in the fuel based on the content of fine salt particles in the exhaust gas collected in the exhaust gas collection step.

[0008] In addition, the boiler monitoring device of the present invention is a device for monitoring the operating state of a boiler, and is equipped with an exhaust gas collection unit that collects exhaust gas generated by the combustion of fuel fed into the boiler's combustion furnace, and an estimation unit that estimates the content of alkali metals and / or chlorine in the fuel based on the content of micro-salt particles in the exhaust gas collected by the exhaust gas collection unit.

[0009] By adopting this method and configuration, it is possible to collect exhaust gas generated by the combustion of fuel fed into the combustion furnace of a boiler, and estimate the alkali metal and chlorine contents in the fuel based on the content of minute salt particles (KCl, etc.) in the collected exhaust gas. Then, based on the estimated alkali metal and chlorine contents in the fuel, it is possible to control the boiler load (furnace temperature, steam temperature, etc.), or change the amount and composition of the fuel.

[0010] In the flue gas collecting step of the boiler monitoring method according to the present invention, flue gas can be collected upstream of the dust collector of the boiler.

[0011] By adopting this method, the contents of alkali metals and chlorine in the fuel can be appropriately estimated based on the content of fine salt particles in the exhaust gas before it is collected by the boiler dust collector.

[0012] In the flue gas collecting step of the boiler monitoring method according to the present invention, the flue gas can be collected at a predetermined frequency.

[0013] By employing such a method, the flue gas can be collected at a predetermined frequency (for example, once a day or more), and the content of fine salt particles in the flue gas can be monitored over time.

[0014] In the flue gas collecting step of the boiler monitoring method according to the present invention, flue gas can be collected when the type of fuel is changed and / or when an abnormality is detected in the operating state of the boiler.

[0015] By adopting this method, it is possible to obtain information on the correlation between the type of fuel and the content of fine salt particles in the exhaust gas, and information on the correlation between boiler abnormalities and the content of fine salt particles in the exhaust gas.

[0016] The boiler control method of the present invention includes the boiler monitoring method already described and a control step of controlling the boiler load and / or boiler maintenance operation based on the content estimated in the estimation step of the boiler monitoring method.

[0017] In addition, the boiler control device of the present invention comprises the boiler monitoring device already described and a control unit that controls the boiler load and / or boiler maintenance operation based on the content estimated by the estimation unit of the boiler monitoring device.

[0018] By adopting this method and configuration, the alkali metal and chlorine contents in the fuel can be estimated based on the content of fine salt particles in the exhaust gas generated by the combustion of fuel fed into the boiler's combustion furnace, and the boiler load (furnace temperature, steam temperature, etc.) and boiler maintenance operations (cleaning operations using a soot blower or the like on the heat transfer surfaces of the superheater and economizer, the pulse frequency of the bag filter, etc.) can be controlled based on the estimated contents. In this way, by quantitatively understanding the alkali metal and chlorine contents in the boiler fuel and controlling the boiler load, etc. based on these contents, it is possible to extend the life of existing boilers.

[0019] The fuel adjustment method according to the present invention includes the boiler monitoring method described above and an adjustment step of changing at least one of the amount, composition, type, and fuel mixing ratio of the fuel fed into the combustion furnace, the amount of additives fed into the combustion furnace, the amount of bed material fed into the combustion furnace, and / or the amount of bed material extracted from the combustion furnace, based on the content estimated in the estimation step of the boiler monitoring method.

[0020] The fuel adjustment device according to the present invention comprises the boiler monitoring device already described, and an adjustment unit that changes at least one of the amount, composition, type, and fuel mixing ratio of the fuel fed into the combustion furnace, the amount of additives fed into the combustion furnace, the amount of bed material fed into the combustion furnace, and / or the amount of bed material extracted from the combustion furnace, based on the content estimated by the estimation unit of the boiler monitoring device.

[0021] This method and configuration allows the alkali metal and chlorine contents of the fuel to be estimated based on the content of fine salt particles in the exhaust gas generated by the combustion of fuel fed into the combustion furnace of a boiler, and then, based on the estimated contents, it is possible to change at least one of the amount, composition, type, and co-firing ratio of the fuel fed into the combustion furnace, the amount of additives fed into the combustion furnace, the amount of bed material fed into the combustion furnace, and / or the amount of bed material extracted from the combustion furnace. By quantitatively determining the alkali metal and chlorine contents of the boiler fuel and adjusting the amount of fuel and the amount of the bed material (additives and bed material) based on the estimated contents, it is possible to extend the life of existing boilers and respond to fluctuations in the fuel properties of the input fuel (e.g., wood chips, tires, RPF (Refuse Paper & Plastic Fuel)), increases and decreases in corrosive components, etc., during boiler operation.

[0022] The boiler of the present invention comprises a heat recovery section that recovers the heat of the combustion gas generated in the combustion furnace, and a dust collector that filters and collects soot contained in the gas that has passed through the heat recovery section.In order to monitor the content of fine salt particles in the gas that has passed through the heat recovery section, a connection section is provided to which a recovery pipe is connected that can recover gas in the piping that connects the heat recovery section and the dust collector.

[0023] By adopting this configuration, the flue gas before being collected by the boiler's dust collector can be collected through the piping that connects the heat recovery unit and the dust collector and the recovery pipe, which makes it possible to appropriately monitor the content of fine salt particles (such as KCl) in the flue gas before being collected by the dust collector. [Effects of the Invention]

[0024] According to the present invention, it is possible to monitor the content of fine salt particles in the exhaust gas of a boiler using a relatively simple method, and to appropriately estimate the content of alkali metals and chlorine in the fuel. [Brief explanation of the drawings]

[0025] [Figure 1]1 is a schematic diagram showing the overall configuration of a boiler according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of correlation information used for content estimation in an embodiment of the present invention (a graph showing the correlation between measurements taken by an alkali metal ion monitor and the alkali metal content in fuel). [Figure 3] FIG. 2 is a diagram showing an example of correlation information used for content estimation in an embodiment of the present invention (a graph showing the correlation between the measurement value obtained by a chlorine detector tube and the chlorine content in fuel). [Figure 4] 1 is a flowchart illustrating a boiler monitoring method, a boiler control method, and a fuel adjustment method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, various embodiments of the present invention will be described with reference to the drawings. Note that the following various embodiments are merely preferred application examples, and the scope of application of the present invention is not limited to these.

[0027] First, a fluidized bed (CFB (Circulating Fluidized Bed) boiler (hereinafter referred to as "CFB boiler") 1 in each embodiment of the present invention will be described with reference to FIG.

[0028] The CFB boiler 1 includes a combustion furnace 2 that burns fuel and heats water in a sealed container to generate steam, a cyclone separator 4 that separates solids from the combustion gas (hereinafter referred to as "exhaust gas") G generated in the combustion furnace 2, a heat recovery section 6 that recovers the heat of the exhaust gas G, a return line 8 that returns the fly ash separated from the exhaust gas G in the cyclone separator 4, i.e., a portion of the bed material separated from the exhaust gas G, to the bottom of the combustion furnace 3, a bag filter 10 that filters and collects soot and dust contained in the exhaust gas G that has passed through the heat recovery section 6, and a central processing unit 100 that performs integrated control of the various components of the CFB boiler 1.

[0029] The combustion furnace 2 is an external circulation type fluidized bed combustion furnace. Various fuels (e.g., biomass fuels such as rice husks and EFBs (Empty Fruit Bunches), wood chips, tires, RPF, etc.) are fed into the combustion furnace 2 through a fuel inlet (not shown). Among these, biomass fuels such as rice husks and EFBs are low-grade fuels containing large amounts of alkaline components such as potassium (K) and sodium (Na). A bed material composed primarily of quartz particles is also fed into the combustion furnace 2 through the fuel inlet. Air is supplied to the bed material from below, causing it to flow and forming a fluidized bed (hereinafter referred to as "bed") F. The formation of the bed F promotes fuel combustion. The bed material contains bottom ash (BA), which is formed by the condensation, melting, and aggregation of components in the biomass fuel, which adhere to the sand as seeds, or by chemical reactions on the sand surface.

[0030] The exhaust gas G produced as a result of combustion rises within the combustion furnace 2, carrying with it some of the bed material. A gas outlet 2A for discharging the exhaust gas is provided at the top of the combustion furnace 2. A discharge port (not shown) for discharging bottom ash BA is provided at the bottom of the combustion furnace 2. A supply adjustment mechanism is provided at the fuel inlet of the combustion furnace 2, which can change the amount, composition, type, and mixed combustion ratio of the fuel, the amount of additives supplied, and the amount of bed material supplied. A discharge adjustment mechanism is provided at the discharge outlet of the combustion furnace 2, which can change the amount of bed material extracted. These supply adjustment mechanism and discharge adjustment mechanism are controlled by an adjustment unit 40 (described below) of the central processing unit 100, thereby adjusting the amount of fuel input to the combustion furnace 2 and the amount of bed material extracted from the combustion furnace 2.

[0031] The cyclone separator 4 is disposed adjacent to the combustion furnace 2 and is connected to the combustion furnace 2 via a gas outlet 2A. The cyclone separator 4 functions as a solid-gas separator, receiving the exhaust gas G discharged from the combustion furnace 2 and the bed material entrained in the exhaust gas G, separating the exhaust gas G from the bed material by centrifugal separation, returning the bed material to the combustion furnace 2, and sending the exhaust gas G to the heat recovery section 6. A return line 8 is connected to the cyclone separator 4.

[0032] The heat recovery section 6 is provided with various heat exchange tubes (for example, a superheater that generates superheated steam and an economizer that preheats boiler feedwater) for recovering heat from the exhaust gas. The superheater uses the heat of the exhaust gas to superheat steam to generate superheated steam. The superheated steam passes through piping (not shown) and is supplied to a turbine (not shown) or the like outside the CFB boiler 1 for use in power generation. The economizer transfers the heat of the exhaust gas to the boiler feedwater to preheat the boiler feedwater.

[0033] The return line 8 consists of a pipe connected to the bottom of the combustion furnace 2, with a loop seal 8A installed midway up the line. The loop seal 8A is equipment that prevents the backflow of exhaust gas G from the combustion furnace 2. The bed material sent from the cyclone separator 4 accumulates inside the loop seal 8A. The bed material inside the loop seal 8A is then fed into the combustion furnace 2 through a return chute 8B at the outlet of the loop seal 8A.

[0034] The bag filter 10 is an example of a dust collector according to the present invention, and is used to filter and collect fine particles such as soot (including fly ash FA) contained in the exhaust gas G that has passed through the heat recovery section 6. Fly ash FA refers to particles formed by condensation, melting, and aggregation of the components themselves in the biomass fuel, which is a fluidized medium (including a finer portion of the particle-formed bottom ash BA). A pipe 16 that connects the heat recovery section 6 and the bag filter 10 is provided with a connection section 16A to which a recovery pipe 22 (described below) is connected in order to recover the exhaust gas flowing through the pipe 16.

[0035] The bag filter 10 has a dust collection chamber in which multiple cylindrical filter cylinders made of filter cloth are suspended, and a hopper located below the dust collection chamber for collecting soot removed from the filter cylinders. The bag filter 10 also has compressed air piping for momentarily injecting compressed air from the top of each filter cylinder to generate a pulsed jet airflow to remove soot accumulated on the outer surface of each filter cylinder. The timing of the compressed air injection is controlled by a control unit 30 (described below) of the central processing unit 100.

[0036] The filtered exhaust gas G that has passed through the bag filter 10 is sucked by a suction pump 12 and discharged from a chimney 14 to the outside of the CFB boiler 1. The soot (including fly ash FA) collected by the bag filter 10 is collected from an outlet (not shown) provided below the hopper.

[0037] The central processing unit 100 is configured with a memory for storing various control programs and various control data, a processor for executing various control programs, and the like, and has multiple functional units (e.g., an estimation unit 28, a control unit 30, an adjustment unit 40, etc.) Each functional unit will be described in detail later.

[0038] First Embodiment Next, a boiler monitoring device 20 according to a first embodiment of the present invention will be described with reference to FIGS.

[0039] The boiler monitoring device 20 according to this embodiment is a device for monitoring the operating state of the CFB boiler 1, and includes an exhaust gas collecting unit (recovery pipe 22, water tank 24, suction pump 26) and an estimating unit .

[0040] The flue gas collection unit functions to collect flue gas generated by the combustion of fuel fed into the combustion furnace 2 of the CFB boiler 1. The flue gas collection unit includes a recovery pipe 22 connected to the pipe 16 that connects the heat recovery unit 6 and the bag filter 10, a water tank 24 in which water is stored, and a suction pump 26. The upper end of the recovery pipe 22 is connected to the pipe 16, and the lower end of the recovery pipe 22 is immersed in the water tank 24. The suction pump 26 sucks air from the water tank 24, lowering the pressure in the water tank 24 below atmospheric pressure. This allows the flue gas in the pipe 16 (i.e., upstream of the bag filter 10) to be sucked through the recovery pipe 22 and collected in the water tank 24. The collected flue gas also contains soot before being filtered and collected by the bag filter 10. The operation of the suction pump 26 is controlled by a supervisor of the CFB boiler 1.

[0041] The estimation unit 28 functions to estimate the alkali metal and chlorine contents in the fuel based on the content of fine salt particles in the exhaust gas collected by the exhaust gas collection unit, and is one of the functional units of the central processing unit 100. In this embodiment, the weight per unit volume (mg / L) of fine salt particles (KCl, etc.) contained in the exhaust gas collected in the water tank 24 via the recovery pipe 22 is measured using an alkali metal ion monitor and a chlorine detector tube (not shown), the measured values ​​are input to the central processing unit 100, and the estimation unit 28 estimates the weight per unit weight (mg / kg) of the alkali metal and chlorine in the fuel based on the input measured values.

[0042] The estimation unit 28 estimates the alkali metal content (mg / kg) in the fuel of the CFB boiler 1 based on the measurement value (the content (mg / L) of alkali metal ions (e.g., potassium ions or sodium ions) in the collected flue gas) measured by the alkali metal ion monitor. In this embodiment, correlation information between the measurement value by the alkali metal ion monitor and the alkali metal content in the fuel is obtained in advance by experiment, and this correlation information is used to perform the estimation. An example of the correlation information is a linear graph L1 as shown in FIG. 2.

[0043] Furthermore, the estimation unit 28 estimates the chlorine content (mg / kg) in the fuel of the CFB boiler 1 based on the measurement value (chlorine ion content (mg / L) in the collected flue gas) from the chlorine detector tube. In this embodiment, correlation information between the measurement value from the chlorine detector tube and the chlorine content in the fuel is obtained in advance by experiment, and estimation is performed using this correlation information. An example of the correlation information is a linear graph L2 as shown in FIG. 3.

[0044] In this embodiment, an upper limit value U1 (FIG. 2) is set for the alkali metal content in the fuel, and an upper limit value U2 (FIG. 3) is set for the chlorine content in the fuel. When at least one of the alkali metal and chlorine contents in the fuel estimated by the estimation unit 28 exceeds the respective upper limit values ​​U1 and U2, boiler control and fuel adjustment, which will be described later, are performed.

[0045] In this embodiment, instead of estimating the content using the estimation unit 28 of the boiler monitoring device 20, the monitor of the CFB boiler 1 manually estimates the content. That is, the monitor samples water from the water tank 24 in which the exhaust gas in the pipe 16 has been dissolved, measures the content (mg / L) of micro salt particles (alkali metal ions and chlorine ions) contained in the sampled water using an alkali metal ion monitor and a chlorine detector tube, and estimates the content (mg / kg) of alkali metals and chlorine in the fuel with reference to graphs L1 and L2 as shown in Figures 2 and 3. If the respective upper limit values ​​U1 and U2 are exceeded, the monitor can also perform boiler control and fuel adjustment, as described below.

[0046] Next, the control unit 30 of the central processing unit 100 according to this embodiment will be described.

[0047] The control unit 30 is one of the functional units of the central processing unit 100, and controls the load and / or maintenance operation of the CFB boiler 1 based on the alkali metal and chlorine contents in the fuel estimated by the estimation unit 28 or a monitor of the CFB boiler 1. The boiler monitoring device 20 and the control unit 30 in this embodiment constitute a boiler control device in the present invention.

[0048] When at least one of the alkali metal and chlorine contents in the fuel estimated by the estimation unit 28 exceeds the respective upper limit values ​​U1, U2, the control unit 30 controls the load (output) of the CFB boiler 1 so as to lower the temperature inside the combustion furnace 2 of the CFB boiler 1 and the steam temperature generated by the heat recovery unit 6, thereby allowing the boiler to continue operating.

[0049] Furthermore, when at least one of the alkali metal and chlorine contents in the fuel estimated by the estimation unit 28 or the supervisor of the CFB boiler 1 exceeds the respective upper limit values ​​U1, U2, the control unit 30 can control the operation of the soot blower to clean the heat transfer surfaces of the superheater and economizer in the heat recovery unit 6 of the CFB boiler 1 more frequently than usual, thereby suppressing deposit adhesion to the surfaces, or can control the injection frequency of compressed air injected from the compressed air piping of the bag filter 10 of the CFB boiler 1 to be higher than usual, thereby recovering the dust collection function of the bag filter 10. These controls on the operation of the soot blower and the control of the injection frequency of compressed air correspond to maintenance operations for the CFB boiler 1.

[0050] In this embodiment, instead of the control unit 30 controlling the various components of the CFB boiler 1, it is also possible for a supervisor of the CFB boiler 1 to manually operate the various components of the CFB boiler 1 to control the load and maintenance operations of the CFB boiler 1.

[0051] Next, the adjustment unit 40 of the central processing unit 100 according to this embodiment will be described.

[0052] The adjustment unit 40 is one of the functional units of the central processing unit 100. Based on the content estimated by the estimation unit 28, the adjustment unit 40 changes at least one of the amount, composition, type, and fuel mix ratio of the fuel fed to the combustion furnace 2 of the CFB boiler 1, as well as the amount of additives fed to the combustion furnace 2, the amount of bed material fed to the combustion furnace 2, and the amount of bed material withdrawn from the combustion furnace 2. Here, "changing" the feed or withdrawal amount means changing the feed or withdrawal amount from a first amount to a second amount. This includes not only setting either the first or second amount to zero (transitioning from a state in which no feed or withdrawal is performed to a state in which it is performed, or from a state in which feed or withdrawal is performed to a state in which it is not performed), but also the first and second amounts being the same (the change in the feed or withdrawal amount is zero (i.e., the feed or withdrawal amount is not changed)). The boiler monitoring device 20 and the adjustment unit 40 in this embodiment constitute a fuel adjustment device of the present invention.

[0053] When at least one of the alkali metal and chlorine contents in the fuel estimated by the estimation unit 28 exceeds the respective upper limit values ​​U1, U2, the adjustment unit 40 controls the supply adjustment mechanism provided at the fuel inlet of the combustion furnace 2 to reduce the amount of fuel fed into the combustion furnace 2 of the CFB boiler 1, change the fuel composition or type to one with less alkali or chlorine, or change the fuel mixing ratio to an appropriate value, thereby allowing the boiler to continue operating.

[0054] In addition, when at least one of the alkali metal and chlorine contents estimated by the estimation unit 28 exceeds the respective upper limit values ​​U1, U2, the adjustment unit 40 increases the supply amount of additives fed to the combustion furnace 2 of the CFB boiler 1, controls the supply adjustment mechanism provided at the fuel inlet of the combustion furnace 2 to increase the supply amount of bed material fed to the combustion furnace 2, or controls the discharge adjustment mechanism provided at the discharge outlet of the combustion furnace 2 to increase the amount of bed material extracted from the combustion furnace 2, thereby allowing the boiler to continue operation.

[0055] In this embodiment, instead of the adjustment unit 40 controlling the device, the supervisor of the CFB boiler 1 manually adjusts the amount of fuel input, etc., and controls the load on the CFB boiler 1, thereby allowing the boiler to continue operating.

[0056] Next, the boiler monitoring method according to this embodiment will be described with reference to the flowchart of FIG.

[0057] First, flue gas generated by the combustion of fuel fed into the combustion furnace 2 of the CFB boiler 1 is collected using a flue gas collection unit (recovery pipe 22, water tank 24, suction pump 26) (flue gas collection step: S1). In the flue gas collection step S1 of this embodiment, flue gas is collected upstream of the bag filter 10 of the CFB boiler 1, as described above. The timing and frequency of flue gas collection can be appropriately set depending on the specifications of the CFB boiler 1, etc. For example, flue gas can be collected at a predetermined time more than once a day, when the type of fuel is changed, or when an abnormality is detected in the operating status of the CFB boiler 1. This makes it possible to monitor the content of fine salt particles in the flue gas over time and to obtain information on the correlation between the type of fuel and the content of fine salt particles in the flue gas, and information on the correlation between boiler abnormalities and the content of fine salt particles in the flue gas.

[0058] Next, the alkali metal and chlorine contents in the fuel are estimated based on the content of the fine salt particles in the flue gas collected in the flue gas collecting step S1 (estimation step: S2). As already described, the supervisor of the CFB boiler 1 estimates the alkali metal content in the fuel using the correlation (for example, the linear graph L1 shown in FIG. 2) between the measurement value from the alkali metal ion monitor (the content (mg / L) of alkali metal ions in the collected flue gas) and the content (mg / kg) of alkali metals in the fuel of the CFB boiler 1, and also estimates the chlorine content in the fuel using the correlation (for example, the linear graph L2 shown in FIG. 3) between the measurement value from the chlorine detector tube (the content (mg / L) of chlorine ions in the collected flue gas) and the content (mg / kg) of chlorine in the fuel of the CFB boiler 1.

[0059] Next, the supervisor of the CFB boiler 1 determines whether or not at least one of the contents of alkali metals and chlorine in the fuel estimated in the estimation step S2 exceeds predetermined upper limits U1, U2 (determination step: S3). If it is determined in the determination step S3 that the estimated contents of alkali metals and chlorine in the fuel are equal to or less than the upper limits U1, U2, the process returns to the flue gas collection step S1 and the subsequent steps are repeated.

[0060] On the other hand, if it is determined in the determination step S3 that the estimated contents of alkali metals and chlorine in the fuel exceed the upper limits U1 and U2, the supervisor of the CFB boiler 1 controls the load and / or maintenance operation of the CFB boiler 1 (boiler control step: S4), and also changes at least one of the amount, composition, type, and mixed-fuel ratio of the fuel fed to the combustion furnace 2 of the CFB boiler 1, the amount of additives fed to the combustion furnace 2, the amount of bed material fed to the combustion furnace 2, and / or the amount of bed material withdrawn from the combustion furnace 2 (fuel, etc. adjustment step: S5). Note that, as already mentioned, "changing" the feed amount or withdrawal amount means changing the feed amount or withdrawal amount from a first amount to a second amount, and includes not only setting either the first amount or the second amount to zero, but also making the first amount and the second amount the same.

[0061] In the boiler control step S4, the supervisor of the CFB boiler 1 can continue boiler operation by controlling the load (output) of the CFB boiler 1 so as to reduce the temperature inside the combustion furnace 2 of the CFB boiler 1 and the temperature of the steam generated by the heat recovery section 6. In addition, in the boiler control step S4, the supervisor of the CFB boiler 1 can control the operation of the soot blower to clean the heat transfer surfaces of the superheater and economizer in the heat recovery section 6 of the CFB boiler 1 more frequently than usual, thereby suppressing deposit adhesion to these surfaces, or can restore the dust collection function of the bag filter 10 by controlling the injection frequency of compressed air injected from the compressed air piping of the bag filter 10 of the CFB boiler 1 to be higher than usual.

[0062] In the fuel adjustment step S5, the supervisor of the CFB boiler 1 controls the supply adjustment mechanism provided at the fuel inlet of the combustion furnace 2 to reduce the amount of fuel fed to the combustion furnace 2 of the CFB boiler 1, change the fuel composition or type to one with less alkali or chlorine, or change the fuel mix ratio to an appropriate value, thereby controlling the load of the CFB boiler 1 and allowing the boiler to continue operation. Also, in the fuel adjustment step S5, the supervisor of the CFB boiler 1 controls the supply adjustment mechanism provided at the fuel inlet of the combustion furnace 2 to increase the supply amount of additives fed to the combustion furnace 2 of the CFB boiler 1, or the supply amount of bed material fed to the combustion furnace 2, or controls the discharge adjustment mechanism provided at the discharge outlet of the combustion furnace 2 to increase the amount of bed material withdrawn from the combustion furnace 2, thereby controlling the load of the CFB boiler 1 and allowing the boiler to continue operation.

[0063] The flue gas collecting step S1 and the estimation step S2 in this embodiment constitute an example of a boiler monitoring method in the present invention. The flue gas collecting step S1, the estimation step S2, the determination step S3, and the boiler control step S4 in this embodiment constitute an example of a boiler control method in the present invention (here, the determination step S3 and the boiler control step S4 constitute an example of a control step in the present invention). The flue gas collecting step S1, the estimation step S2, the determination step S3, and the fuel, etc. adjusting step S5 in this embodiment constitute an example of a fuel, etc. adjusting method in the present invention (here, the determination step S3 and the fuel, etc. adjusting step S5 constitute an example of an adjusting step in the present invention).

[0064] In the boiler monitoring method according to the embodiment described above, flue gas generated by the combustion of fuel fed into the combustion furnace 2 of the CFB boiler 1 is collected, and the alkali metal and chlorine contents in the fuel can be estimated based on the content of fine salt particles in the collected flue gas. Then, based on the estimated content of alkali metal and chlorine in the fuel, it is possible to control the load of the CFB boiler 1 (furnace temperature, steam temperature, etc.) or change the amount or composition of fuel. In particular, in the flue gas collection step S1 of this embodiment, the flue gas is collected upstream of the bag filter 10 of the CDB boiler 1. Therefore, the content of fine salt particles (e.g., KCl) in the flue gas before it is collected by the bag filter 10 can be monitored, and the alkali metal and chlorine contents in the fuel can be appropriately estimated.

[0065] Furthermore, in the boiler control method according to the embodiment described above, the load of the CFB boiler 1 (furnace temperature, steam temperature, etc.) and maintenance operations of the CFB boiler 1 (cleaning of the heat transfer surfaces of the superheater and economizer with a soot blower, etc., pulse frequency of the bag filter, etc.) can be controlled based on the alkali metal and chlorine contents in the fuel estimated from the content of fine salt particles in the exhaust gas generated by the combustion of the fuel fed into the combustion furnace of the CFB boiler 1. In this way, by quantitatively understanding the alkali metal and chlorine contents in the fuel in the CFB boiler 1 and controlling the boiler load, etc. based on these contents, it is possible to extend the life of existing boilers.

[0066] Furthermore, in the fuel adjustment method according to the embodiment described above, at least one of the amount, composition, type, and fuel-mixing ratio of the fuel input to the combustion furnace 2, the amount of additives input to the combustion furnace 2, the amount of bed material input to the combustion furnace, and / or the amount of bed material extracted from the combustion furnace 2 can be changed based on the alkali metal and chlorine contents of the fuel estimated from the content of fine salt particles in the exhaust gas generated by the combustion of the fuel input to the combustion furnace 2 of the CFB boiler 1. In this way, by quantitatively determining the alkali metal and chlorine contents of the fuel in the CFB boiler 1 and adjusting the amount of fuel and the amount of the combustion furnace contents (additives and bed material) based on the alkali metal and chlorine contents, the life of the existing boiler can be extended and it is possible to manage fluctuations in the fuel properties of the input fuel (wood chips, tires, RPF (Refuse Paper & Plastic Fuel), etc.) during boiler operation, increases and decreases in corrosive components, etc.

[0067] Second Embodiment Next, a boiler monitoring method according to a second embodiment of the present invention will be described.

[0068] In this embodiment, instead of the supervisor of the CFB boiler 1 manually estimating, controlling, and adjusting the content, the estimation unit 28 of the boiler monitoring device 20 is used to estimate the content of alkali metals and chlorine in the fuel, the control unit 30 controls the load and maintenance operation of the CFB boiler 1, and the adjustment unit 40 adjusts the amount of fuel input, etc. Since the configurations of the boiler monitoring device 20 (estimation unit 28), the control unit 30, and the adjustment unit 40 are the same as those of the first embodiment, detailed explanations will be omitted. Note that the contents of each step of the boiler monitoring method, etc. according to this embodiment are the same as those of the first embodiment (although the main body has been changed), and therefore will be explained with appropriate reference to the flowchart in FIG. 4.

[0069] First, flue gas generated by the combustion of fuel fed into the combustion furnace 2 of the CFB boiler 1 is collected using a flue gas collection unit (recovery pipe 22, water tank 24, suction pump 26) (flue gas collection step: S1). In the flue gas collection step S1 of this embodiment, flue gas is also collected upstream of the bag filter 10 of the CFB boiler 1. In this embodiment, the control unit 30 of the central processing unit 100 controls the suction pump 26 to collect flue gas at a predetermined time and frequency. The time and frequency of flue gas collection can be set appropriately depending on the specifications of the CFB boiler 1, etc. For example, flue gas can be collected at a predetermined time more than once a day, when the type of fuel is changed, or when an abnormality is detected in the operating status of the CFB boiler 1.

[0070] Next, the estimation unit 28 of the central processing unit 100 estimates the alkali metal and chlorine contents in the fuel based on the content of fine salt particles in the flue gas collected in the flue gas collection step S1 (estimation step: S2). As already described, the estimation unit 28 estimates the alkali metal content in the fuel using the correlation (for example, the linear graph L1 shown in FIG. 2) between the measurement value from the alkali metal ion monitor (the content (mg / L) of alkali metal ions in the collected flue gas) and the content (mg / kg) of alkali metals in the fuel of the CFB boiler 1, and also estimates the chlorine content in the fuel using the correlation (for example, the linear graph L2 shown in FIG. 3) between the measurement value from the chlorine detector tube (the content (mg / L) of chlorine ions in the collected flue gas) and the content (mg / kg) of chlorine in the fuel of the CFB boiler 1.

[0071] Next, the central processing unit 100 determines whether or not at least one of the contents of alkali metals and chlorine in the fuel estimated in the estimation step S2 exceeds predetermined upper limits U1, U2 (determination step: S3). If it is determined in the determination step S3 that the estimated contents of alkali metals and chlorine in the fuel are equal to or less than the upper limits U1, U2, the process returns to the exhaust gas collection step S1 and the subsequent steps are repeated.

[0072] On the other hand, if it is determined in the judgment step S3 that the estimated alkali metal and chlorine contents in the fuel exceed the upper limit values ​​U1, U2, the control unit 30 of the central processing unit 100 controls the load and / or maintenance operation of the CFB boiler 1 (boiler control step: S4), and the adjustment unit 40 of the central processing unit 100 changes at least one of the amount, composition, type, and mixing ratio of fuel fed to the combustion furnace 2 of the CFB boiler 1, the supply amount of additives fed to the combustion furnace 2, the supply amount of bed material fed to the combustion furnace 2, and / or the amount of bed material extracted from the combustion furnace 2 (fuel, etc. adjustment step: S5).

[0073] In the boiler control step S4, the control unit 30 controls the load (output) of the CFB boiler 1 so as to reduce the temperature inside the combustion furnace 2 of the CFB boiler 1 and the temperature of the steam generated by the heat recovery unit 6, thereby allowing the boiler to continue operation. In addition, in the boiler control step S4, the control unit 30 controls the operation of the soot blower to clean the heat transfer surfaces of the superheater and economizer in the heat recovery unit 6 of the CFB boiler 1 more frequently than usual, thereby suppressing deposit adhesion to these surfaces, and controls the injection frequency of compressed air injected from the compressed air piping of the bag filter 10 of the CFB boiler 1 to be higher than usual, thereby quickly restoring the dust collection function of the bag filter 10.

[0074] In the fuel etc. adjustment step S5, the adjustment unit 40 controls a supply adjustment mechanism provided at the fuel inlet of the combustion furnace 2 to reduce the amount of fuel fed to the combustion furnace 2 of the CFB boiler 1, change the fuel composition or type to one with less alkali metal or chlorine, or change the fuel mix ratio to an appropriate value, thereby controlling the load on the CFB boiler 1 and allowing the boiler to continue operation. Also, in the fuel etc. adjustment step S5, the adjustment unit 40 controls a supply adjustment mechanism provided at the fuel inlet of the combustion furnace 2 to increase the supply amount of additives fed to the combustion furnace 2 of the CFB boiler 1, or controls a supply adjustment mechanism provided at the fuel inlet of the combustion furnace 2 to increase the supply amount of bed material fed to the combustion furnace 2, or controls a discharge adjustment mechanism provided at the discharge outlet of the combustion furnace 2 to increase the amount of bed material withdrawn from the combustion furnace 2, thereby controlling the load on the CFB boiler 1 and allowing the boiler to continue operation.

[0075] The boiler monitoring device 20 according to the embodiment described above collects flue gas generated by the combustion of fuel fed into the combustion furnace 2 of the CFB boiler 1, and estimates the alkali metal and chlorine contents in the fuel based on the content of fine salt particles in the collected flue gas. Based on the estimated content of alkali metal and chlorine in the fuel, the load of the CFB boiler 1 (furnace temperature, steam temperature, etc.) can be controlled, or the amount and composition of fuel can be changed. In particular, in the flue gas collection step S1 of this embodiment, the flue gas is collected upstream of the bag filter 10 of the CDB boiler 1. Therefore, the content of fine salt particles (e.g., KCl) in the flue gas before it is collected by the bag filter 10 can be monitored, and the alkali metal and chlorine contents in the fuel can be appropriately estimated.

[0076] Furthermore, the boiler control device (boiler monitoring device 20 and control unit 30) according to the embodiment described above can control the load (furnace temperature, steam temperature, etc.) of the CFB boiler 1 and maintenance operations (cleaning of the heat transfer surfaces of the superheater and economizer with a soot blower, etc., pulse frequency of the bag filter, etc.) of the CFB boiler 1 based on the alkali metal and chlorine contents in the fuel estimated from the content of fine salt particles in the exhaust gas generated by the combustion of the fuel fed into the combustion furnace of the CFB boiler 1. In this way, by quantitatively understanding the alkali metal and chlorine contents in the fuel in the CFB boiler 1 and controlling the boiler load, etc. based on these contents, it is possible to extend the life of existing boilers.

[0077] Furthermore, the fuel adjustment device (boiler monitoring device 20 and adjustment unit 40) according to the above-described embodiment can change at least one of the amount, composition, type, and fuel-mixing ratio of the fuel input to the combustion furnace 2, the amount of additives input to the combustion furnace 2, the amount of bed material input to the combustion furnace, and / or the amount of bed material extracted from the combustion furnace 2, based on the alkali metal and chlorine contents of the fuel estimated from the content of fine salt particles in the exhaust gas generated by the combustion of the fuel input to the combustion furnace 2 of the CFB boiler 1. In this way, by quantitatively determining the alkali metal and chlorine contents of the fuel in the CFB boiler 1 and adjusting the amount of fuel and the amount of the combustion furnace contents (additives and bed material) based on the alkali metal and chlorine contents, the life of the existing boiler can be extended and it is possible to manage fluctuations in the fuel properties of the input fuel (such as wood chips, tires, and RPF (Refuse Paper & Plastic Fuel)) during boiler operation, increases and decreases in corrosive components, and the like.

[0078] The present invention is not limited to the above-described embodiments, and any design modifications made by a person skilled in the art to these embodiments as appropriate are also included within the scope of the present invention as long as they comprise the features of the present invention. In other words, the elements of the above-described embodiments and their arrangement, materials, conditions, shape, size, etc. are not limited to those exemplified and can be modified as appropriate. Furthermore, the elements of the above-described embodiments can be combined to the extent technically possible, and such combinations are also included within the scope of the present invention as long as they comprise the features of the present invention.

[0079] The disclosure of Japanese Patent Application No. 2021-066036, filed on April 8, 2021, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described in the specification are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference. [Industrial Applicability]

[0080] The present invention is useful for monitoring the content of fine salt particles in boiler exhaust gas using a relatively simple method and for appropriately estimating the content of alkali metals and chlorine in fuel. [Explanation of symbols]

[0081] 1...CFB boiler 2...Combustion furnace 6...Heat recovery section 10...Bag filter (dust collector) 16...Plumbing 16A...Connection 20...Boiler monitoring device 22...Recovery pipe (exhaust gas collection section) 24...Water tank (exhaust gas collection section) 26...Suction pump (exhaust gas collection section) 28…Estimation Department 30...Control unit 40...Adjustment section S1: Exhaust gas collection process S2…Estimation process S3… Determines the project (control project, adjust project) S4…ボイラControl Engineering (Control Engineering) S5… Fuel and other adjustment works (adjustment works)

Claims

1. A method for monitoring an operating state of a boiler, comprising: an exhaust gas collecting step of collecting exhaust gas generated by combustion of fuel input into the combustion furnace of the boiler; an estimation step of estimating the content of alkali metals and / or chlorine in the fuel based on the content of fine salt particles in the exhaust gas collected in the exhaust gas collecting step; A boiler monitoring method comprising:

2. The boiler monitoring method according to claim 1 , wherein the flue gas collecting step collects flue gas upstream of a dust collector of the boiler.

3. The boiler monitoring method according to claim 1 or 2, wherein the flue gas collecting step collects the flue gas at a predetermined frequency.

4. 3. The boiler monitoring method according to claim 1, wherein the flue gas collecting step collects the flue gas when the type of fuel is changed and / or when an abnormality is detected in the operating state of the boiler.

5. A boiler monitoring method according to any one of claims 1 to 4; a control step of controlling a load on the boiler and / or a maintenance operation of the boiler based on the content estimated in the estimation step of the boiler monitoring method; A boiler control method comprising:

6. A boiler monitoring method according to any one of claims 1 to 4; an adjusting step of changing at least one of the amount, composition, type, and mixed-fuel ratio of the fuel fed into the combustion furnace, the supply amount of an additive fed into the combustion furnace, the supply amount of a bed material fed into the combustion furnace, and / or the extraction amount of a bed material from the combustion furnace, based on the content estimated in the estimating step of the boiler monitoring method; A method for adjusting fuel, etc., including:

7. A device for monitoring the operating state of a boiler, an exhaust gas collecting unit that collects exhaust gas generated by combustion of fuel input into the combustion furnace of the boiler; an estimation unit that estimates the content of alkali metals and / or chlorine in the fuel based on the content of fine salt particles in the exhaust gas collected by the exhaust gas collection unit; A boiler monitoring device comprising:

8. The boiler monitoring device according to claim 7; a control unit that controls a load on the boiler and / or a maintenance operation of the boiler based on the content estimated by the estimation unit of the boiler monitoring device; A boiler control device comprising:

9. The boiler monitoring device according to claim 7; an adjusting unit that changes at least one of the amount, composition, type, and mixed combustion ratio of the fuel fed into the combustion furnace, the supply amount of additives fed into the combustion furnace, the supply amount of bed material fed into the combustion furnace, and / or the extraction amount of bed material from the combustion furnace, based on the content estimated by the estimating unit of the boiler monitoring device; A fuel adjustment device comprising:

10. a heat recovery section that recovers heat from the combustion gas generated in the combustion furnace; a dust collector that filters and collects soot and dust contained in the gas that has passed through the heat recovery section; a connection part to which a recovery pipe capable of recovering gas in a pipe that connects the heat recovery part and the dust collector in communication with each other is connected; an estimation unit that estimates the content of alkali metals and / or chlorine in the fuel to be charged into the combustion furnace based on the content of fine salt particles in the gas recovered through the recovery pipe; A boiler equipped with:

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