JP6543384B1 - Detection method of mercury large input situation of waste incinerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: A method for detecting a large amount of mercury input that can detect early and accurately the occurrence of a large amount of mercury input in a waste incinerator and is not affected by mercury contamination even if a large amount of mercury input is generated I will provide a. A method for detecting a large amount of introduced mercury performs a detection process, an accumulation process, and a determination process on a waste incinerator. In the detection step, the mercury emission line selection filter is selected from the light generated in the combustion chamber using a mercury emission line selection filter that selectively transmits the emission line of a specific wavelength emitted based on the energy level specific to mercury. A light detector detects the light intensity of the transmitted light transmitted. In the accumulation step, the light intensity of the transmitted light detected in the detection step is accumulated in time series. In the judgment step, the judgment criterion is calculated based on the light intensity of the transmitted light accumulated in the accumulation step and its time change, and when the change amount of the light intensity of the transmitted light exceeds the judgment criterion, Determine that it has occurred. [Selected figure] Figure 4

Description

  The present invention mainly relates to a method for detecting that a large amount of mercury has been introduced into a waste incinerator or the like at one time.

  Conventionally, a method has been proposed to detect a situation in which a large amount of mercury has been input to a waste incinerator at one time (hereinafter, a large amount of mercury has been input). Patent Documents 1 and 2 disclose a method of detecting a large amount of mercury input.

  The mercury removal system of Patent Document 1 attaches a mercury continuous analyzer to a flue through which exhaust gas such as a waste incinerator flows, and detects the concentration of mercury contained in the exhaust gas based on the detection result of the mercury continuous analyzer. Do. Further, the mercury removal system determines that a large amount of mercury has been input when the concentration of mercury detected by the mercury continuous analyzer exceeds a predetermined concentration.

  In the waste incinerator of Patent Document 2, an inlet for removing a mercury is disposed upstream of the bag filter. In addition, a mercury detection device is disposed upstream of the mercury removal agent inlet. The mercury detection apparatus comprises an intake unit for taking in the exhaust gas, a sampling path for sending the taken-in exhaust gas, and a mercury analyzer for analyzing the amount of mercury.

  Further, Patent Document 3 discloses a waste incinerator that detects harmful substances different from mercury. Specifically, the waste incinerator includes a spectrum analyzer and a combustion diagnostic device. The spectrum analyzer divides the light input from the opening in the combustion chamber for each wavelength by a spectrometer, and performs spectrum analysis by detecting the light intensity of the light for each wavelength. The combustion diagnosis device detects harmful substances (dioxins, NOx, CO, etc.) in the gas based on the result of the spectrum analysis.

JP, 2014-213308, A JP, 2017-205761, A Unexamined-Japanese-Patent No. 11-51353 gazette

  In Patent Document 1, in order to attach a continuous mercury analyzer to the flue, it is necessary to connect a tube with a narrow diameter or the like to the flue and to connect the continuous mercury analyzer to the tube. In addition, the sampling path of patent document 2 is comprised by such a tube. However, when a large amount of mercury is introduced, the exhaust gas containing a large amount of mercury passes through the tube and reaches the mercury continuous analyzer, so the inner surface of the tube is contaminated with mercury, making the next measurement difficult there is a possibility. Moreover, in this type of configuration, it is necessary to move the exhaust gas to the mercury continuous analyzer via the tube after occurrence of a large amount of mercury input, so it takes some time to detect mercury. Therefore, the introduction of the mercury removing agent may be delayed.

  In Patent Document 3, there is also a limit to the resolution of the spectroscope, and for example, when the emission line of another substance having a wavelength close to the emission line of the harmful substance is generated, or the light intensity of the emission line of the harmful substance does not increase very much. In such cases, harmful substances may not be detected properly. In particular, in waste incinerators, wastes of various characteristics are input, and since the types of waste input can not be specified, such problems are likely to occur.

  The present invention has been made in view of the above circumstances, and the main object of the present invention is to detect early that a large amount of mercury has occurred in a waste incinerator at an early and accurate time. It is an object of the present invention to provide a method for detecting a large input of mercury which is not affected by mercury pollution even if it occurs.

  The problem to be solved by the present invention is as described above, and next, means for solving the problem and its effect will be described.

  According to an aspect of the present invention, the following method for detecting a large amount of mercury input to a waste incinerator is provided. That is, the method for detecting a large amount of mercury input includes a primary combustion zone for performing primary combustion, and a secondary combustion zone for performing secondary combustion for burning primary combustion gas including unburned gas generated in the primary combustion. And a waste incinerator comprising a combustion chamber. The mercury large input situation detection method performs the detection process, the accumulation process, and the determination process on the waste incinerator. In the detection step, the mercury emission line is selected from the light generated in the combustion chamber using a mercury emission line selection filter that selectively transmits the emission line of a specific wavelength emitted based on an energy level specific to mercury. A light detector detects the light intensity of the transmitted light transmitted through the filter. In the accumulation step, light intensities of the transmitted light detected in the detection step are accumulated in time series. In the determination step, a determination criterion is calculated based on the light intensity of the transmitted light accumulated in the accumulation step and its time change, and when the change amount of the light intensity of the transmitted light exceeds the determination criterion, It is determined that a large amount of mercury has been introduced.

  As a result, by detecting the mercury emission line contained in the light of the flame generated in the combustion chamber, it is possible to detect a large amount of mercury input early. Also, in this method, the mercury emission line selective filter and the light detector do not need to be in contact with the mercury, so that the method is not affected by the mercury contamination. Furthermore, the mercury emission line can be accurately detected by using the mercury emission line selection filter, as it is not affected by the resolution of the spectrometer as compared with the configuration using the spectrometer.

  According to the present invention, it is possible to quickly and accurately detect the occurrence of a large amount of mercury in the waste incinerator, and the large amount of mercury is not affected by the mercury contamination even if a large amount of mercury is generated. A situation detection method can be realized.

The schematic block diagram of the waste incineration plant containing an incinerator. Functional block diagram of the incinerator. Sectional drawing which shows a mode that a mercury bright line selection filter and a photodetector are arrange | positioned. The flowchart which shows the process which detects generation | occurrence | production of the mercury large injection | pouring situation.

  <Whole Configuration of Waste Incinerator> First, a waste incinerator 100 including the incinerator 1 of the present embodiment will be described with reference to FIG. FIG. 1 is a schematic block diagram of a waste incinerator 100 including an incinerator 1 according to an embodiment of the present invention. In the following description, the terms “upstream” and “downstream” mean upstream and downstream in the flow direction of waste, combustion gas, combustion gas, exhaust gas and the like.

  As shown in FIG. 1, the waste incinerator 100 includes an incinerator (waste incinerator) 1, a boiler 30, and a steam turbine power plant 35. The incinerator 1 burns the supplied waste. The detailed configuration of the incinerator 1 will be described later.

  The boiler 30 generates steam using the heat generated by the combustion of waste. The boiler 30 generates steam (superheated steam) by heat exchange between high temperature combustion gas generated in the furnace and water using a large number of water pipes 31 and superheater pipes 32 provided on the flow path wall. The steam generated by the water pipe 31 and the superheater pipe 32 is supplied to the steam turbine power plant 35.

  The steam turbine power plant 35 is configured including a not shown turbine and a power generator. The turbine is rotationally driven by the steam supplied from the water pipe 31 and the superheater pipe 32. The power generation device generates electric power using the rotational driving force of the turbine.

  <Configuration of Incinerator 1> The incinerator 1 includes a dust collecting device 40 for supplying waste into the furnace. The dust collecting apparatus 40 includes a waste feeding hopper 41 and a dust collecting apparatus main body 42. The waste input hopper 41 is a portion into which waste is input from outside the furnace. The dust collecting apparatus main body 42 is located at the bottom of the waste input hopper 41 and is configured to be movable in the horizontal direction. The dust collecting apparatus main body 42 supplies the waste charged into the waste charging hopper 41 to the downstream side. The movement speed of the dust collecting apparatus main body 42, the number of movements per unit time, the movement amount (stroke), and the position (movement range) of the stroke end are controlled by the control device 90 shown in FIG. The dust collecting apparatus may be of a type moving at a slight angle with respect to the horizontal direction.

  The waste supplied into the furnace by the dust collector 40 is supplied to the combustion chamber 2. The combustion chamber 2 includes a primary combustion zone 10 and a secondary combustion zone 14. The primary combustion zone 10 is a space for primary combustion. Primary combustion is the reaction of the input waste with a gas for primary combustion for combustion. The primary combustion gas is a gas containing oxygen supplied for primary combustion. The primary combustion gas includes primary air, circulating exhaust gas, and a mixed gas thereof. The primary air is air taken from the outside and is a gas that is not used for combustion or the like (i.e. excluding the circulating exhaust gas). Therefore, the primary air also includes a gas obtained by heating air taken in from the outside. Moreover, primary combustion generates primary combustion gas (flue gas after primary combustion) including unburned gas such as CO.

  The primary combustion zone 10 is composed of a drying unit 11, a combustion unit 12 and a post combustion unit 13. Wastes are supplied by the transport unit 20 in the order of the drying unit 11, the combustion unit 12, and the post-combustion unit 13. The conveying unit 20 is configured by a drying grate 21 provided in the drying unit 11, a combustion grate 22 provided in the combustion unit 12, and a post combustion grate 23 provided in the post combustion unit 13. There is. Therefore, the transport unit 20 is composed of a plurality of stages of grate. Each grate is provided on the bottom of each part and wastes are placed. The grate is composed of a movable grate arranged in the waste transfer direction and a fixed grate. The movable grate intermittently advances and reverses to transfer waste to the downstream side. In addition, waste can be stirred. The operation of the grate is controlled by the controller 90. Further, the grate is formed with a gap of a size allowing the passage of gas.

  The drying unit 11 is a part that dries the waste supplied to the incinerator 1. Wastes from the drying unit 11 are dried by primary air supplied from below the drying grate 21 and radiant heat of combustion in the adjacent combustion unit 12. At that time, thermal decomposition gas is generated from wastes of the drying unit 11 by thermal decomposition. Further, the wastes of the drying unit 11 are conveyed toward the burning unit 12 by the drying grate 21.

  The combustion unit 12 is a portion that mainly burns the waste dried in the drying unit 11. In the combustion unit 12, the waste mainly burns and flames are generated. The waste in the combustion unit 12, the ash generated by the combustion, and the unburned material that can not be burned are conveyed by the combustion grate 22 toward the post-combustion unit 13. Further, the primary combustion gas and flame generated in the combustion unit 12 pass through the throttle unit 17 and flow toward the post-combustion unit 13. The combustion grate 22 is provided at the same height as the dry grate 21, but may be provided at a lower position than the dry grate 21.

  The post-combustion unit 13 is a portion that burns waste (unburned material) that could not be burned by the combustion unit 12. In the post-combustion unit 13, the radiation heat of the primary combustion gas and the primary air promote the combustion of the unburned matter that could not be burned in the combustion unit 12. As a result, most of the unburned matter becomes ash and the unburned matter decreases. The ash generated in the post-combustion unit 13 is conveyed toward the chute 24 by the post-fired grate 23 provided on the bottom surface of the post-combustion unit 13. The ash transported to the chute 24 is discharged to the outside of the waste incinerator 100. Although the post combustion grate 23 of the present embodiment is provided at a lower position than the combustion grate 22, it may be provided at the same height as the combustion grate 22.

  As described above, since the reaction that occurs in the drying unit 11, the combustion unit 12, and the post-combustion unit 13 differs, the wall surfaces and the like are configured according to the reactions that occur. For example, since flame combustion occurs in the combustion unit 12, a structure having a higher fire resistance level than the drying unit 11 is employed.

  As described above, in the primary combustion zone 10 of the incinerator 1 of the present embodiment, drying, combustion, and post-combustion are performed on the input waste. In the incinerator 1 of the present embodiment, since the respective constituent stages are clearly separated, the above three processes are performed stepwise. The present invention is applicable to incinerators of various configurations. For example, the present invention is applicable to incinerators in which each component stage is not clearly divided. The present invention is also applicable to incinerators in which at least one of the drying stage and the post-combustion stage does not exist. The present invention is also applicable to an incinerator without a grate, such as a fluidized bed incinerator or a fixed bed incinerator.

  The secondary combustion zone 14 is a space for secondary combustion. The secondary combustion is to make the unburned gas contained in the primary combustion gas react with the gas for secondary combustion and burn it. The secondary combustion gas is a gas containing oxygen supplied for secondary combustion. The secondary combustion gas includes secondary air, circulating exhaust gas, and a mixed gas thereof. The secondary air is air taken from the outside and is not used for combustion or the like (i.e., a gas excluding circulation exhaust gas). By performing the secondary combustion, the completeness of combustion can be promoted. The secondary combustion zone 14 extends upward from the drying unit 11, the combustion unit 12, and the post-combustion unit 13, and secondary air is supplied along the way. Thereby, the primary combustion gas is mixed and stirred with the secondary air, and the unburned gas contained in the primary combustion gas is burned in the secondary combustion zone 14.

  The high temperature secondary combustion gas discharged in the secondary combustion is discharged as an exhaust gas after passing through the boiler 30 as described above. The exhaust gas discharged from the incinerator 1 is purified by a filter type dust collector 6 disposed downstream. Also, in the path (fluent) until the exhaust gas reaches the dust collector 6, a drug for reducing the concentration of harmful substances (HCl, SOx, dioxins, etc.) contained in the exhaust gas is introduced. Ru.

  Moreover, the waste incineration apparatus 100 is equipped with the chemical | medical agent tank 7 and the valve | bulb 8 as a structure for throwing in this chemical | medical agent. In the medicine tank 7, plural kinds of medicines corresponding to the harmful substance to be reduced are stored individually. The valve 8 has a mechanism for adjusting the amount of medicine supplied to the flue. The valve 8 is provided for each type of medicine. The control device 90 determines the type and amount of the medicine to be used based on the detection result of the property of the exhaust gas, the target value, and the like, and performs control to change the opening degree of the valve 8 accordingly. This drug contains a drug such as slaked lime or activated carbon having a function of adsorbing and removing mercury in exhaust gas. It is possible to suppress serious pollution of the dust collector 6 with mercury by increasing the amount of the chemical having a function of adsorbing mercury when a large amount of mercury is introduced.

  <Supply of primary combustion gas and secondary combustion gas> The gas supply device 50 is a device for supplying gas (primary combustion gas, secondary combustion gas) into the combustion chamber 2. The gas supply device 50 of the present embodiment includes a primary air supply unit 51, a secondary air supply unit 52, and an exhaust gas supply unit 53. Each supply is constituted by a blower for attracting or delivering the gas.

  The primary air supply unit 51 supplies the primary air to the combustion chamber 2 via the primary supply path 71. The primary supply path 71 is provided below the drying stage air box 25 provided below the drying grate 21, the combustion stage air box 26 provided below the combustion grate 22, and the post combustion grate 23. It is a path for supplying primary air to the post-combustion stage air boxes 27 respectively. In the primary supply path 71, a first damper 81 for adjusting the supply amount of primary air supplied to the drying stage air box 25, and a second damper 82 for adjusting the supply amount of primary air supplied to the combustion step air box 26 A third damper 83 is provided to adjust the amount of supply of primary air supplied to the post-combustion stage air box 27. As shown in FIG. 2, the first damper 81, the second damper 82, and the third damper 83 are controlled by the control device 90.

  Further, a heater may be provided in the primary supply path 71 so that the temperature of the primary air supplied to the combustion chamber 2 can be adjusted. Further, as described above, since the primary combustion gas also includes the circulating exhaust gas and the mixed gas, they may be supplied to the combustion chamber 2. Further, in the present embodiment, the primary combustion gas is supplied from below to the primary combustion zone 10, but may be supplied from the side of the primary combustion zone 10 or the like. In addition, the primary combustion gas may be supplied upstream of the primary combustion zone 10 as long as it is used for the primary combustion.

  The secondary air supply unit 52 supplies secondary air to the combustion chamber 2 via the secondary supply passage 72. Specifically, the secondary air supply unit 52 supplies the secondary air to the air gas storage space 16 of the incinerator 1 from the upper portion (ceiling portion) thereof, and a portion where the combustion gas changes its direction by the throttle unit 17 The secondary air is supplied to (in the vicinity of the throttle portion 17), and the secondary air is supplied to the secondary combustion zone 14. The secondary supply path 72 is provided with a fifth damper 85 for adjusting the supply amount of secondary air supplied to the vicinity of the air gas holding space 16 and the throttle unit 17. As shown in FIG. 2, the fifth damper 85 is controlled by the controller 90.

  The exhaust gas supply unit 53 supplies (recirculates) the exhaust gas discharged from the waste incineration facility 100 into the furnace via the circulation exhaust gas supply path 73. A part of the exhaust gas discharged from the waste incineration facility 100 and purified by the dust collector 6 is supplied by the exhaust gas supply unit 53 to the incinerator 1 from both side surfaces of the combustion unit 12 (surfaces on the front side and the rear side). Be done. In addition, the position where exhaust gas is supplied is not specifically limited. For example, the exhaust gas may be supplied from above the ceiling of the incinerator 1, or may be supplied from only one side. By supplying the exhaust gas to the incinerator 1, the oxygen concentration in the incinerator 1 is reduced, and it is possible to suppress the local excessive increase of the combustion temperature. As a result, the generation of NOx can be suppressed. Further, in the circulating exhaust gas supply path 73, a fourth damper 84 for adjusting the supply amount of the circulating exhaust gas is provided. As shown in FIG. 2, the fourth damper 84 is controlled by the controller 90.

  <Various Sensors and Control Device> As shown in FIGS. 1 and 2, the incinerator 1 is provided with a plurality of sensors for grasping the combustion state and the like. Specifically, the incinerator gas temperature sensor 91, the incinerator outlet gas temperature sensor 92, the CO gas concentration sensor 93, the NOx gas concentration sensor 94, and the light detector 95 are included in the incinerator 1. It is provided.

  The incinerator gas temperature sensor 91 is disposed in the incinerator 1 (for example, downstream of the air gas holding space 16 and upstream of the post-combustion unit 13), and detects the gas temperature in the incinerator to control the controller 90 Output to The incinerator outlet gas temperature sensor 92 is disposed in the vicinity of the outlet of the incinerator 1 (for example, downstream of the secondary combustion zone 14 and upstream of the boiler 30), detects the temperature of the incinerator outlet gas, and Output. The CO gas concentration sensor 93 is disposed downstream of the dust collector 6, detects the CO gas concentration (incinerator exhaust CO gas concentration) contained in the exhaust gas, and outputs it to the control device 90. The NOx gas concentration sensor 94 is disposed downstream of the dust collector 6, detects the NOx gas concentration (incinerator exhaust NOx gas concentration) contained in the exhaust gas, and outputs it to the control device 90.

  The photodetector 95 is intended to detect an emission line (hereinafter referred to as a mercury emission line) of a specific wavelength emitted based on an energy level specific to mercury. To explain further, the mercury emission line is light observed as an emission line spectrum when the emission of mercury is spectrally analyzed. Hereinafter, a configuration for detecting a mercury emission line generated inside the combustion chamber 2 will be described.

  Since the energy level of mercury is raised by heating, mercury emission lines may be generated at any position inside the combustion chamber 2. Therefore, the light detector 95 may be configured to detect light generated anywhere in the combustion chamber 2. However, in the case of a high temperature flame, a mercury emission line is particularly likely to be generated, so in the present embodiment, the light of the flame is to be detected. Here, in the combustion chamber 2, as described above, a flame is generated in the primary combustion. This flame also exists in the secondary combustion zone 14, since it extends upwards due to the influence of the flow of combustion gases flowing from the primary combustion zone 10 to the secondary combustion zone 14. And, in the secondary combustion zone 14, as compared to the primary combustion zone 10 in which various unburned wastes exist, emission lines of other elements are less likely to be generated, and therefore mercury emission lines can be detected more accurately. As described above, the present embodiment aims to detect a mercury emission line included in light of a flame in the secondary combustion zone 14.

  As shown in FIG. 3, the light detector 95 is disposed in the vicinity of the furnace wall 2 a of the secondary combustion zone 14. Specifically, as shown in FIG. 3, a through hole 2 b is formed in the furnace wall 2 a of the combustion chamber 2. Further, a portion (a boundary portion between the combustion chamber 2 and the furnace wall 2 a) of the through hole 2 b which is open on the combustion chamber 2 side is referred to as an opening 2 c. In the through hole 2 b, a heat resistant glass 61 and a mercury bright line selection filter 62 are disposed.

  The heat resistant glass 61 is disposed closer to the combustion chamber 2 than the mercury emission line selection filter 62. The heat resistant glass 61 is a member that transmits light and has heat resistant characteristics.

  The mercury emission line selection filter 62 is disposed closer to the combustion chamber 2 than the light detector 95. The mercury emission line selection filter 62 is a filter that transmits only light of wavelengths in the passband and does not transmit light of other wavelengths. The pass band of the mercury emission line selection filter 62 is a very narrow range including the wavelength of the mercury emission line. The wavelengths of main mercury emission lines are: 365.483 nm, 366.288 nm, 366.328 nm, 390.641 nm, 398.398 nm, 404.656 nm, 407.781 nm, 435.835 nm and 491. 604 nm · 546.074 nm · 576.969 nm · 597.065 nm. Thus, for example, since there are a plurality of mercury emission lines in the 366 nm band, the pass band of the mercury emission line selection filter 62 may include the wavelengths of the plurality of mercury emission lines. Of course, only the wavelength of one mercury emission line may be included. In addition, since the wavelength of the mercury emission line exists besides the above, the pass band of the mercury emission line selection filter 62 may include the wavelength other than the above.

  The light detector 95 detects the light transmitted through the mercury emission line selection filter 62 (hereinafter, transmitted light) among the light of the flame that can be observed in the secondary combustion zone 14. The photodetector 95 of the present embodiment is an imaging device having an imaging element. The imaging device is configured to be able to detect the wavelength of the pass band of the mercury emission line selection filter 62. When the light detector 95 is an imaging device, it is possible to create an image showing the distribution of the light intensity of the transmitted light in the imaging range. Moreover, the imaging device which image | photographs the inside of the combustion chamber 2 is already arrange | positioned, and when not currently used, etc., the mercury large injection | throwing-in situation can be detected using this existing imaging device.

  The photodetector 95 may have another configuration as long as it can detect transmitted light. For example, the photodetector 95 may be a photocell, a photodiode or the like. When the light detector 95 is a photocell, the light intensity of the transmitted light can be detected based on the generated electromotive force. When the light detector 95 is a photodiode, the light intensity of the transmitted light can be detected based on the output electric signal (specifically, based on the current value of the output current). When the light detector 95 is a photocell or a single photodiode, the magnitude of the light intensity of the transmitted light can be detected, but the distribution can not be detected. However, the cost can be reduced as compared with the case of using an imaging device.

  In the present embodiment, the mercury emission line selection filter 62 and the light detector 95 are disposed in the through hole 2 b and in a linear shape in the axial direction, but may be disposed at different positions. For example, when the light transmitted through the heat resistant glass 61 is input from one end of the optical fiber and the mercury emission line selection filter 62 and the light detector 95 are disposed at the other end of the optical fiber, the positions of the mercury emission line selection filter 62 and the light detector 95 The degree of freedom can be improved.

  The control device 90 is configured by a CPU, a RAM, a ROM, and the like, and performs various calculations and controls the entire incinerator 1. Hereinafter, among the controls performed by the control device 90, control for detecting a large amount of input of mercury will be described with reference to the flowchart of FIG. Note that, in the present embodiment, the control device 90 performs all the processes in FIG. 4, but another control device may perform at least one process.

  The photodetector 95 detects the light intensity of the transmitted light (that is, the mercury emission line) (detection step). This detection process is always performed. The control device 90 acquires the detection value of the light intensity of the transmitted light detected by the light detector 95 (S101).

  Next, the control device 90 accumulates the light intensity of the transmitted light in time series (S102, accumulation step). Specifically, the control device 90 associates the time and the light intensity of the transmitted light, and stores them in the storage device provided in the control device 90 or an external storage device. In addition, when the light detector 95 is an imaging device, a distribution of light intensity corresponding to the imaging position can be obtained. Therefore, by integrating the light intensity of each pixel or calculating the average, the light intensity can be calculated from this distribution. Calculate

  Next, the control device 90 calculates a determination criterion based on the accumulated light intensity of the transmitted light and its time change (S103). The criterion is a criterion for determining the occurrence of a large amount of mercury input. Moreover, the light intensity of the transmitted light detected in the normal state where a large amount of mercury is not generated is different depending on the configuration, control, and the like of the incinerator 1. Therefore, in the present embodiment, the determination criterion is calculated based on past detection values without updating the determination criterion, and the determination criterion is updated.

  In addition, “a large amount of mercury input”, which is a problem here, is not a state where mercury is constantly supplied in a large amount, but a state where mercury, which is usually added only in a very small amount, is temporarily introduced in large amounts. Based on that, not only the magnitude of the simple light intensity, but also the judgment criteria in consideration of the time change are calculated. For example, the determination criteria include a first threshold related to the amount of change in light intensity and a second threshold related to the magnitude of light intensity. That is, the determination criterion is satisfied when the amount of change in light intensity per predetermined time is equal to or greater than the first threshold and the magnitude of the average light intensity in the predetermined time is equal to or greater than the second threshold. . Note that the second threshold may be omitted depending on the predetermined time and the value of the first threshold.

  Next, the control device 90 determines whether the light intensity of the transmitted light (specifically, the magnitude and the change amount of the light intensity) exceeds the determination reference (S104, determination step). When the light intensity of the transmitted light does not exceed the determination reference, the control device 90 performs the processes of steps S101 to S103 again to update the determination reference because a large amount of mercury has not been input.

  On the other hand, when it is determined that the light intensity of the transmitted light exceeds the determination reference, the controller 90 controls the valve 8 to start increasing the amount of the drug having the function of adsorbing mercury, since a large amount of mercury has occurred. To do (S105). Note that there are various measures to be taken when a large amount of mercury is introduced, and therefore, the treatment of increasing the amount of a chemical having a function of adsorbing mercury is one example. That is, in place of or in addition to increasing the amount of the drug having the function of adsorbing mercury, at least one of processing for generating an alarm sound and processing for stopping the incinerator 1 may be further performed.

  Here, in the conventional method of analyzing exhaust gas, it is necessary to draw in the exhaust gas to a mercury analyzer with a tube or the like, and it also takes time to perform the process of analyzing the mercury concentration although it depends on the analysis method. On the other hand, in the configuration of the present embodiment, a large amount of mercury is introduced and a large amount of mercury emission lines are generated in the incinerator 1, and at the same time, the mercury emission lines are transmitted through the mercury emission line selection filter 62 to the light detector 95. As it is input, it is possible to detect the abnormal rise of the mercury concentration earlier than before. In addition, since the light detector 95 detects an abnormal increase of the mercury concentration without contacting the mercury, there is no influence of the contamination with the high concentration mercury.

  Further, in the present embodiment, the mercury emission line is detected by one light detector 95 to determine the large amount of mercury input, but the mercury emission line may be detected by a plurality of light detectors 95. In this case, the wavelength of the mercury emission line to be detected may be made different in each of the light detectors 95. Specifically, for each light detector 95, a mercury emission line selection filter 62 having a different passband is disposed. Thereby, a plurality of mercury emission lines different in wavelength can be individually detected. Therefore, for example, when light which is a bright line of another element and whose wavelength is close to the first mercury bright line is generated in the combustion chamber 2, the light detector 95 for detecting the first mercury bright line is used. The detected light intensity may be high even though a large amount of mercury has not been introduced (an erroneous detection may occur). However, the emission line of this different element has no influence on the detection result of the photodetector 95 whose detection target is a mercury emission line other than the first. Therefore, the detection accuracy of the mercury emission line can be improved by detecting a plurality of mercury emission lines and comparing the detection results.

  Furthermore, when this configuration is employed, a mercury emission line selection filter so that light generated at the same location in the combustion chamber 2 can be detected by the plurality of light detectors 95 in order to prevent erroneous detection of the mercury emission line more reliably. It is preferable to arrange 62 and the photodetector 95 etc. For example, when two light detectors 95 are arranged, two openings 2c are formed to be adjacent to each other by the same furnace wall 2a, and a mercury emission line selection filter 62 and a light detector 95 are arranged at each opening 2c. It is preferable to do.

  As described above, the incinerator 1, which is the object of the method for detecting a large amount of introduced mercury according to the present embodiment, includes the primary combustion zone 10 for performing primary combustion, and primary combustion including unburned gas generated in primary combustion. And a secondary combustion zone 14 for performing secondary combustion for burning a gas. The mercury large amount input situation detection method performs the detection step, the accumulation step, and the determination step on the incinerator 1. In the detection step, the mercury emission line selection of the light generated in the combustion chamber 2 is performed using the mercury emission line selection filter 62 that selectively transmits the emission line of a specific wavelength emitted based on the energy level specific to mercury. The light intensity of the transmitted light transmitted through the filter 62 is detected by the light detector 95. In the accumulation step, the light intensity of the transmitted light detected in the detection step is accumulated in time series. In the determination step, a determination criterion (first threshold) is calculated based on the light intensity of the transmitted light accumulated in the accumulation step and its time change, and when the variation of the light intensity of the transmitted light exceeds the determination criterion, It is determined that a large amount of mercury has been introduced.

  Thus, by detecting the mercury emission line contained in the light generated in the combustion chamber 2, it is possible to detect a large amount of mercury input early. Also, in this method, the mercury emission line selective filter and the light detector do not need to be in contact with the mercury, so that the method is not affected by the mercury contamination. Furthermore, the mercury emission line can be accurately detected by using the mercury emission line selection filter, as it is not affected by the resolution of the spectrometer as compared with the configuration using the spectrometer.

  Further, in the method for detecting a large amount of introduced mercury according to the present embodiment, in the detection step, the light intensity of the transmitted light transmitted through the mercury emission line selection filter 62 among the light of the flame reaching the secondary combustion zone 14 from the primary combustion zone 10 To detect

  As a result, the mercury emission line is easily generated in the flame, and the mercury emission line can be favorably detected because the emission lines of other elements are relatively small particularly in the flame which has reached the secondary combustion zone 14.

  Further, in the method for detecting a large amount of introduced mercury according to this embodiment, the mercury emission line selection filter 62 is disposed in a region through which the light passing through the opening 2 c formed in the furnace wall 2 a constituting the secondary combustion zone 14 passes. There is.

  Thus, it is possible to directly detect the light of the flame that has reached the secondary combustion zone 14 from the primary combustion zone 10.

  Further, in the method of detecting a large amount of introduced mercury according to the present embodiment, in the detection step, the light intensity of the transmitted light is detected using an imaging device that detects an image.

  Thereby, the distribution of the light intensity of the transmitted light in the imaging range can be detected. Moreover, the existing imaging device can be utilized to detect a large amount of mercury input.

  Further, in the method for detecting a large amount of introduced mercury according to the present embodiment, in the detecting step, a photovoltaic cell generating an electromotive force corresponding to the light intensity of the irradiated light or a signal corresponding to the light intensity of the irradiated light It is preferable to detect the light intensity of the transmitted light using a photodiode to be generated.

  Thereby, the light intensity of the transmitted light can be detected with a simple and low-cost configuration.

  The preferred embodiment of the present invention has been described above, but the above-described configuration can be modified, for example, as follows.

  Another band-pass filter may be disposed between the heat-resistant glass 61 and the mercury emission line selection filter 62 in order to block light in a band which can not be blocked by the mercury emission line selection filter 62.

  In the above embodiment, although the light detector 95 such as an imaging device and the mercury emission line selection filter 62 are separately disposed, they may be integrally configured. For example, the mercury emission line selection filter 62 may be attached to the light entrance of the imaging device.

1 Incinerator (Waste incinerator)
10 Primary combustion zone 14 Secondary combustion zone 62 Mercury emission line selection filter 95 Photodetector

Claims (5)

Waste incinerator comprising a combustion chamber having a primary combustion zone for performing primary combustion, and a secondary combustion zone for performing secondary combustion for burning primary combustion gas including unburned gas generated in the primary combustion Against
Transmission of the light generated in the combustion chamber through the mercury emission line selection filter using a mercury emission line selection filter that selectively transmits emission lines of a specific wavelength emitted based on an energy level specific to mercury Detecting the light intensity of the light with a light detector;
An accumulation step of accumulating the light intensity of the transmitted light detected in the detection step in time series;
A judgment criterion is calculated based on the light intensity of the transmitted light accumulated in the accumulation step and its time change, and when the variation amount of the light intensity of the transmitted light exceeds the judgment criterion, a large amount of mercury is introduced A determination step of determining that it has occurred;
A method for detecting a large amount of mercury input in a waste incinerator characterized in that A method for detecting a large amount of mercury input to a waste incinerator according to claim 1, wherein
The mercury in the waste incinerator is characterized in that, in the detection step, the light intensity of the transmitted light transmitted through the mercury emission line selection filter among the light of the flame having reached the secondary combustion zone from the primary combustion zone is detected. How to detect a large input situation. A method for detecting a large amount of mercury input to a waste incinerator according to claim 2, wherein
The mercury emission line selection filter is disposed in a region through which light passing through an opening formed in a furnace wall constituting the secondary combustion zone passes, and detects a large amount of mercury in the waste incinerator. Method. A method for detecting a large amount of mercury input to a waste incinerator according to any one of claims 1 to 3,
In the detection step, the light intensity of the transmitted light is detected using an imaging device for detecting an image, and the method for detecting a large amount of mercury input in a waste incinerator. A method for detecting a large amount of mercury input to a waste incinerator according to any one of claims 1 to 3,
In the detection step, the light intensity of the transmitted light is generated using a photovoltaic cell that generates an electromotive force according to the light intensity of the irradiated light or a photodiode that generates a signal according to the light intensity of the irradiated light. Method of detecting a large amount of mercury input in a waste incinerator characterized by detecting

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