JP2014094355A - Exhaust gas denitrification system, and regeneration method and catalyst replacement method in exhaust gas denitrification device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system and a method for denitrification of exhaust gas, capable of precisely grasping the concentration distribution of a gas component, and performing efficient denitrification.SOLUTION: The exhaust gas denitrification system includes: an ammonia injection device 104 serving as reducing agent supply means for supplying a reducing agent (NH) into flue gas 102 from a boiler 101; a denitrification device 105 having partitioned denitrification catalysts 106A, 106B, 106C for denitrifying nitrogen oxide (NOx) containing the reducing agent; and a gas component concentration distribution measurement device 110 which is provided on an exit side of the denitrification device, which has probe means having multiple light transmitting tubes 112A (112B, 112C) for measuring concentration distribution of a gas component (NH) in exhaust gas in areas, corresponding to the partitioned denitrification catalysts 106A, 106B, 106C, orthogonal to a gas stream of the denitrification device, and which measures ammonia concentration by laser measurement means. On the basis of the measurement result of the ammonia concentration by the gas component concentration distribution measurement device 110, concentration distribution of ammonia in the partitioned areas is obtained.

Description

  The present invention relates to an exhaust gas denitration system, an exhaust gas denitration device regeneration method, and an exhaust gas denitration device catalyst replacement method.

  Conventionally, a laser gas analyzer is known as an apparatus for measuring the concentration of a specific substance contained in a gas mixture. This laser gas analyzer uses the characteristic that each gaseous gas molecule has a specific light absorption wavelength, irradiates a gas containing a specific substance with laser light, and determines the specific substance from the amount of absorption at that specific wavelength. Is a measure of the concentration.

  The following Patent Document 1 discloses a technique for sucking a gas from a piping unit through which a gas containing ammonia flows and guiding the sucked gas to a laser gas spectrometer to measure the concentration of ammonia contained in the gas. .

Patent Document 2 discloses a sampling pipe inserted into a flue to collect exhaust gas, a flow cell unit connected to the sampling pipe via a heating conduit, and a laser gas analyzer connected to the flow cell unit. An ammonia concentration measuring device is disclosed. In the ammonia concentration measuring device disclosed in Patent Document 2, an adsorbent that adsorbs sulfur trioxide (SO ₃ ) but allows ammonia to pass through the inside of the sampling tube is loaded, and the gas from which sulfur trioxide has been removed from the exhaust gas is added. By introducing it into a laser gas analyzer, the measurement accuracy of ammonia is improved.

JP 2012-8008 A JP 2010-236877 A

The sampling type concentration measuring devices disclosed in Patent Documents 1 and 2 have the following problems.
It is difficult to speed up the measurement when the gas is sucked and led to the measurement pipe.
Since the concentration measurement is performed after the gas is drawn into the measurement pipe, the state of the gas flowing through the pipe and the state of the gas drawn into the measurement pipe (for example, temperature, etc.) differ, and the measurement accuracy decreases. .
Since the concentration is measured by collecting the circulating gas locally, the concentration distribution cannot be acquired even if the local gas concentration can be measured. Further, if concentration measurement is performed by sequentially changing sampling locations, it is possible to acquire a concentration distribution, but it is necessary to suck and discharge gas at each position, which is complicated and takes time.

  In addition, when measuring the concentration of leaked ammonia and nitrogen oxide (NOx), which are gas components in the exhaust gas, at the outlet side of the denitration device, if the exhaust gas is in turbulent flow, the correct gas There is a problem that it is difficult to accurately determine the concentration distribution of components.

  Therefore, for example, when denitrating nitrogen oxides in the exhaust gas of a boiler device, the appearance of an exhaust gas denitration system capable of accurately grasping the gas component concentration distribution and performing efficient denitration is desired.

  In view of the above-described problems, the present invention provides an exhaust gas denitration system and an exhaust gas denitration apparatus that can efficiently perform denitration by accurately grasping the gas component concentration distribution when denitrating nitrogen oxides in exhaust gas. It is an object to provide a method and a catalyst replacement method for an exhaust gas denitration apparatus.

A first invention of the present invention for solving the above-described problems includes a reducing agent supply means for supplying a reducing agent into combustion exhaust gas, and denitration of nitrogen oxides (NOx) in the exhaust gas containing the reducing agent. In the exhaust gas in a region corresponding to the denitration catalyst that is provided on at least one of the inlet side or the outlet side of the denitration device and that is orthogonal to the gas flow of the denitration device. A plurality of probe means for measuring the gas component concentration distribution of the gas component concentration distribution measuring device for measuring by the laser measuring means,
In the exhaust gas denitration system, the gas component concentration distribution is obtained from the measurement result of the gas component concentration distribution measuring device.

A second invention is the exhaust gas denitration system according to the first invention, wherein the gas component is either one or both of ammonia (NH ₃ ) and nitrogen oxide (NOx).

  According to a third invention, in the second invention, when the gas component is ammonia, the ammonia concentration distribution is obtained from the measurement result of the gas component concentration distribution measuring device, and the leaked ammonia concentration is predetermined from the obtained ammonia concentration distribution. An exhaust gas denitration system comprising: a determination unit that determines a section that is equal to or greater than the value; and an adjustment unit that adjusts a reducing agent supply amount from a reducing agent supply unit corresponding to the determined section.

  According to a fourth invention, in the second invention, when the gas component is nitrogen oxide, the nitrogen oxide concentration distribution is obtained from the measurement result of the gas component concentration distribution measuring device, and the NO concentration distribution is obtained from the obtained NO concentration distribution. Judging means for judging a section with insufficient denitration whose concentration is not less than a predetermined value, and adjusting means for adjusting the reducing agent supply amount from the reducing agent supply means corresponding to the judged section with insufficient denitration. An exhaust gas denitration system characterized by

  According to a fifth invention, in the fourth invention, a denitration rate of the denitration catalyst divided from the obtained NO concentration distribution, a judging means for judging the degree of deterioration of the denitration catalyst, and a reduction corresponding to the deteriorated compartment In the exhaust gas denitration system, when the amount of the reducing agent supplied from the agent supply means is adjusted, there is provided an adjusting means for spraying water together with the supply of ammonia or separately from the supply of ammonia.

  According to a sixth invention, in the invention according to any one of the first to fifth inventions, the probe means is exposed to a measurement field by dividing a light transmission tube through which laser light passes and a part of the light transmission tube into a predetermined distance. The exhaust gas denitration system is characterized by having a measurement area.

  A seventh aspect of the present invention is the exhaust gas denitration system according to the sixth aspect of the present invention, wherein the measurement region is different along the longitudinal direction of the light transmission tube and is located in a part of the partitioned region.

  The eighth invention uses the exhaust gas denitration system according to any one of the first to seventh aspects, judges the degree of deterioration of the denitration catalyst divided, and supplies the reducing agent from the reducing agent supply means corresponding to the deteriorated division. In the regeneration method of the exhaust gas denitration apparatus, the solvent is sprayed together with the supply of ammonia or separately from the supply of ammonia to adjust the NOx removal catalyst corresponding to the deteriorated compartment.

  A ninth invention is characterized by using the exhaust gas denitration system according to any one of the first to seventh aspects, judging the degree of deterioration of the compartmentalized denitration catalyst, and exchanging the denitration catalyst of the degraded compartment at the time of inspection. In the exhaust gas denitration apparatus, the catalyst is replaced.

  According to the present invention, the denitration catalyst in the flue is sectioned, and the gas component (for example, ammonia, nitrogen oxide) concentration distribution in the exhaust gas in the region corresponding to the orthogonal dezonation catalyst is measured. The distribution can be grasped. Based on this concentration distribution, the opening degree of the reducing agent can be controlled.

FIG. 1-1 is a schematic diagram of a boiler apparatus including a denitration apparatus according to the first embodiment. FIG. 1-2 is a schematic diagram of a boiler apparatus including another denitration apparatus according to the first embodiment. FIG. 1C is a schematic diagram of the denitration apparatus according to the first embodiment. 1-4 is a schematic diagram of another denitration apparatus according to Embodiment 1. FIG. FIG. 1-5 is a schematic diagram of a boiler apparatus including the denitration apparatus according to the second embodiment. FIG. 2 is an explanatory diagram showing divided regions of the concentration measurement region inside the denitration apparatus. FIG. 3 is a schematic diagram showing the overall configuration of the gas component concentration distribution measuring apparatus installed in the denitration apparatus. FIG. 4 is a perspective view of probe means constituting one basic set. FIG. 5 is a longitudinal sectional view showing a laser beam window on the light transmission side light receiving side of the gas component concentration distribution measuring apparatus installed in the denitration apparatus according to the first embodiment. FIG. 6 is a longitudinal sectional view showing a laser beam window on the light transmission side light receiving side of the gas component concentration distribution measuring apparatus installed in the denitration apparatus according to the first embodiment. FIG. 7 is a system diagram illustrating a schematic configuration example of the ammonia injection device of the denitration apparatus according to the first embodiment. FIG. 8 is a conceptual diagram of absorption spectroscopy measurement. FIG. 9 is an absorption chart for absorption spectroscopy measurement. FIG. 10 is a diagram showing the relationship between the dust concentration in the exhaust gas and the laser light transmittance.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this Example, Moreover, when there exists multiple Example, what comprises combining each Example is also included.

FIG. 1-1 is a schematic diagram of a boiler apparatus including a denitration apparatus according to the first embodiment. FIG. 1-2 is a schematic diagram of a boiler apparatus including another denitration apparatus according to the first embodiment. FIG. 2 is an explanatory diagram showing divided regions of the concentration measurement region inside the denitration apparatus. FIG. 3 is a schematic diagram showing the overall configuration of the gas component concentration distribution measuring apparatus installed in the denitration apparatus. FIG. 4 is a perspective view of probe means constituting one basic set. FIG. 5 is a longitudinal sectional view showing a laser beam window on the light transmission side light receiving side of the gas component concentration distribution measuring apparatus installed in the denitration apparatus according to the first embodiment. FIG. 6 is a longitudinal sectional view showing a laser beam window on the light transmission side light receiving side of the gas component concentration distribution measuring apparatus installed in the denitration apparatus according to the first embodiment. FIG. 7 is a system diagram illustrating a schematic configuration example of the ammonia injection device of the denitration apparatus according to the first embodiment.
As illustrated in FIG. 1A, a boiler apparatus 100 including the exhaust gas denitration system according to the first embodiment includes a reducing agent (for example, ammonia: NH ₃ ) in combustion exhaust gas (hereinafter referred to as “exhaust gas”) 102 from the boiler 101. An ammonia injection device 104 that is a reducing agent supply means for supplying NO, a denitration device 105 having a denitration catalyst 106A, 106B, 106C for denitrating nitrogen oxide (NOx) containing the reducing agent, and the denitration device A plurality of gas components (NH ₃ , NOx) concentration distributions in exhaust gas in a region corresponding to the denitration catalysts 106A, 106B, 106C that are provided on the outlet side of the apparatus and that are orthogonal to the gas flow of the denitration apparatus 105 are measured. Gas probe 112A (112B, 112C) having a light transmission tube and measuring ammonia concentration by laser measuring means. It comprises a concentration distribution measuring apparatus 110, and from the measurement result of the ammonia concentration of the gas component concentration distribution measuring apparatus 110, and requests the concentration distribution of ammonia sectioned areas.
1-1, the code | symbol 107 shows an air preheater and 108 shows a chimney.

  Further, in this embodiment, the control device 20 for obtaining a section with insufficient denitration based on the obtained ammonia concentration distribution, and an adjusting means for adjusting the reducing agent supply amount from the reducing agent supply means corresponding to the section with insufficient denitration. The opening degree setting part 109 which is is provided.

In this embodiment, in order to partition the denitration catalyst constituting the denitration apparatus 105, the interior of the denitration apparatus 105 is divided into predetermined regions by the partition plate 120 as shown in FIGS. 1-1, 2 and 3. .
In addition, when the denitration catalyst is filled in the container without using the partition plate 120, the wall of the container becomes the partitioning means.

As shown in FIG. 2, the partition plate 120 of this embodiment is divided into three rows 106A to 106C from the first wall portion 103a to the second wall portion 103b of the flue wall of the denitration device 105. , as divided from the third wall portion 103c to the fourth wall portion 3 rows 106A-1,106A-2,106A-3 over 103d, the density measurement area of P ₁ to P _9, which is nine compartments A divided region is formed. By measuring the average concentration of ammonia to be measured for each of the divided areas, the concentration distribution of the measurement object in the concentration measurement area can be obtained.

In the present embodiment, a plurality of light transmission tubes 112A (112B, 112C) of measuring means are arranged in the lower end portion of the partition plate 120.
As a result, the exhaust gas after the exhaust gas 102 passes through the denitration catalyst partitioned by the partition plate 120 does not mix with each other, and can be measured in each partitioned region. Therefore, the ammonia concentration distribution in each partition can be measured. It can be measured.

  FIG. 3 is a schematic diagram showing the overall configuration of the gas component concentration distribution measuring apparatus installed in the denitration apparatus. As shown in FIG. 3, the gas component concentration distribution measuring apparatus 110 is provided with probe means having a plurality of light transmission tubes 112A (112B, 112C) for measuring the divided areas.

  Further, as shown in FIG. 3, a light transmitter that is a laser light transmitter that emits laser light from the outside of the measurement field to each of one end sides of the light transmission tubes 112 </ b> A (112 </ b> B, 112 </ b> C) of the plurality of probe means. 11 and a light receiver 12 that is a laser light receiving unit that receives the laser light that has passed through the measurement region outside the measurement field and detects the light intensity of the laser light.

  As shown in FIG. 3, in this embodiment, probe means including light transmission tubes 112A, 112B, and 112C having three different measurement areas L are prepared so as to correspond to the nine sections shown in FIG. Yes. The probe means of the light transmission cylinders 112A to 112C is set as one set, and three sets (I to III) are arranged in the column direction.

FIG. 4 is a perspective view of the probe means constituting one basic set.
As shown in FIG. 4, the probe means for forming three different types of measurement areas L constituting one basic set includes a hollow light transmission tube 112A (112B, 112C) that passes laser light, and the light transmission tube. A part of 112A (112B, 112C) is divided between predetermined distances 112a and 112b, and has a measurement region L that is exposed to the measurement field.
Since the exhaust gas 102 passes through the divided measurement region L, ammonia in the exhaust gas 102 can be measured by laser light.
The measurement region L is interrupted for 1 m, and the laser optical path length is 1 m.

In this way, a part of the light transmission tube 112A (112B, 112C) is divided between the predetermined distances 112a and 112b so as to correspond to the predetermined divided areas P _{1 to} P ₃ for measuring the ammonia concentration, and the measurement area L is formed.
Therefore, on the laser path, the exhaust gas 102 that has passed through the denitration catalyst only in the measurement region L where the light transmission cylinder 112A (112B, 112C) is cut off exists, and in the exhaust gas 102 in the measurement region L The ammonia concentration can be measured by absorption of laser light.

In the present embodiment, as shown in FIG. 3, the light transmission tube 112A includes divided regions (P ₁ , P ₄ , P ₇ ) on the side of the light receiver 12 in the first row I, the second row II, and the third row III. Is provided with a measurement region L that is exposed to a measurement field that is divided between the predetermined distances 112a and 112b.
The light transmission tube 112B is divided between the predetermined distances 112a and 112b so as to correspond to the divided regions (P ₂ , P ₅ , P ₈ ) of the first row I, the second row II, and the third row III. A measurement region L that is exposed to the measurement field is provided.
The light transmission tube 112C is divided between the predetermined distances 112a and 112b so as to correspond to the divided regions (P ₃ , P ₆ , P ₉ ) of the first row I, the second row II, and the third row III. A measurement region L that is exposed to the measurement field is provided.
In addition, illustration of the measurement area | region L is abbreviate | omitted in FIG.

  Therefore, since the concentration of only each divided region of the exhaust gas 102 passing through the denitration catalyst 106 divided by the partition plate 120 is measured, a hollow light transmission is provided in the laser path of the divided region where the concentration is not measured. The cylinder portions of the cylinders 112A to 112C are installed.

  5 and 6 are views schematically showing the laser beam window 15 and the light transmission tube 112A (112B, 112C). As shown in FIGS. 5 and 6, the laser beam window 15 is a hollow member, and is fixed to the surfaces of the walls 103 c and 103 d of the denitration apparatus 105 by the flange 16. Inside the laser beam window 15, a sealing optical glass 17 is provided to block gas in and out between the inside and the outside. The light receiving surface of the sealing optical glass 17 may be formed obliquely rather than perpendicular to the laser light in order to prevent reflection of the laser light.

  An air supply port 18 is provided on each side of the sealing optical glass 17 of the laser beam window 15. By blowing out the seal air 19 from the air supply port 18, it is possible to prevent adhesion of a substance to the sealing optical glass 17. Note that the seal air 19 may be blown out only to the density measurement region S side, not the double-sided side with respect to the sealing optical glass 17.

  Further, the seal air 19 supplied into the light-transmitting tubes 112A to 112C is filled, thereby preventing the inflow (backflow) of the exhaust gas 102 from the opened measurement region L.

  When the light transmission tube 112A (112B, 112C) is installed on the inner wall surface, as shown in FIGS. 5 and 6, for example, the end of the light transmission tube 112A (112B, 112C) is connected to the end of the flange 16. The The diameter of the light transmission tube 112A (112B, 112C) is larger than the diameter of the laser beam window 15, and the seal air 19 supplied to the laser beam window 15 is supplied to the inside of the light transmission tube 112A (112B, 112C). .

  Note that the method of forming the divided regions in the density measurement region is not limited to the above-described nine columns of 3 columns × 3 rows. The number of columns, the number of rows, and the number of divided regions may be other numbers. When the density measurement region is M columns × N rows and P divided regions are formed, laser paths of P probe means are set.

Next, the principle of concentration distribution measurement according to this embodiment will be described with reference to the drawings.
FIG. 8 is a conceptual diagram of absorption spectroscopy measurement. FIG. 9 is an absorption chart for absorption spectroscopy measurement.
The Lambert-Beer law is known as a relational expression indicating the relationship between the light intensity of the laser beam and the concentration of the measurement object.

As shown in FIG. 8, the Lambert-Beer law is that the measurement region, which is the distance of the laser path, between the light transmission point and the light reception point is L, the irradiation intensity of the laser light is I ₀ , and the light reception of the laser light. When the intensity is I (L) and the concentration of the measurement target (ammonia) existing in the distance L is C ₀ , the relationship of the following expression (1) is established.
I (L) = I ₀ exp (−kC ₀ L) (1)
Here, k is a proportionality coefficient set according to the absorbance of the measurement target.

Assuming that the density average value of the divided area for measuring the density of the measurement object is C ₁ and the distance of the laser path in the divided area (measurement area L where the light transmission tube is divided) is L ₁ , the above equation (1) Can be expressed as the following equation (2).
I (L) = I ₀ exp (−kC ₁ L ₁ ) (2)

When irradiating laser light for each preset laser path, the distance of the laser path in the divided area (measurement area that is a place where the light transmission cylinder is divided) L ₁ , the irradiation intensity I ₀ of the laser light, and the laser light received light intensity I (L), since it is known, by the above equation (2) can be calculated the density average value C ₁ of the divided regions is unknown.

  In the gas component concentration distribution measuring apparatus 110 having the above-described configuration, the ammonia concentration distribution in the concentration measurement region is acquired by the following procedure.

Further, since the exhaust gas 102 from the boiler 101 contains soot and dust, if the optical path length of the laser light that is the measurement region L is increased, the light transmittance is attenuated by the effect of soot and dust.
FIG. 10 is a diagram showing the relationship between the dust concentration in the exhaust gas and the laser light transmittance.
In FIG. 10, when the wavelength is 1.5 μm, it is confirmed that measurement is possible with an optical path length of 2.0 m in coal ash having a dust concentration of about 6 g / Nm ³ .
Therefore, when the dust concentration is higher than that, it is preferable to measure with an optical path length of 1.5 m, more preferably around 1 m.

Here, in order to measure the ammonia (NH ₃ ) concentration in the exhaust gas as in this embodiment, a semiconductor laser (semiconductor element: InGaAs can be exemplified. Wavelength: 1.5 μm, output: about 1 mW Can be exemplified).

FIG. 7 is a system diagram illustrating a schematic configuration example of the ammonia injection device of the denitration apparatus according to the first embodiment.
As shown in FIG. 7, the ammonia injection device 104 includes a total flow control valve 23 in the ammonia main system 22 of the flow path pipe connected to the ammonia supply source. The ammonia main system 22 includes a plurality of (six in the illustrated example) ammonia supply systems 26 branched from the header 24 downstream of the total flow control valve 23.

  Further, as shown in FIG. 7, the ammonia supply system 26 includes a flow control source valve 25 and a plurality of (three in the illustrated example) injection nozzles 27, and is a flow path through which the exhaust gas 102 flows. The injection nozzles 27 are installed inside the flue 103 so as to have a grid-like arrangement. The injection nozzle 27 causes the ammonia supplied from the ammonia supply source through the ammonia main system 22, the header 24, and the ammonia supply system 26 of the flow path piping to flow out into the flue 103 in the form of droplets or gas, and burns Ammonia as a reducing agent is injected into the exhaust gas. In addition, ammonia injected in the form of droplets absorbs heat from high-temperature combustion exhaust gas and is gasified.

  The ammonia gas thus injected into the flue 103 is stirred and mixed with the combustion exhaust gas 102 by passing through the mixer. As a result, ammonia reacts with the nitrogen oxides and passes through the denitration catalyst 106 in the denitration device 105, so that the nitrogen oxides are removed from the combustion exhaust gas by being decomposed into water and nitrogen.

A measured value of ammonia (NH ₃ ) concentration measured by the gas component concentration distribution measuring device 110 is input to the opening setting unit 109 via the control device 20. Upon receiving such an ammonia concentration input, the opening setting unit 109 sets the opening (opening control) of the total flow control valve 23 based on the average value of the ammonia concentration, and adjusts the ammonia concentration at a plurality of locations. Based on this, the opening of each flow control source valve 25 is set (opening control). That is, the opening setting unit 109 outputs the opening control signals of the total flow control valve 23 and the flow control source valve 25.

  In this case, the opening degree control of the flow control source valve 25 by the opening degree setting unit 109 is performed based on a control map that defines a correlation between a predetermined ammonia concentration and an opening degree for each flow control source valve 25. In other words, the denitration device 105 is produced by obtaining the correlation data in advance through experiments or the like because various conditions (the channel system of the flue 103, the channel cross-sectional area, the type of fuel, etc.) differ for each boiler 101. The control map is stored in the opening setting unit 109. In this control map, the opening degree of the flow control source valve 25 that differs for each of the plurality of ammonia supply systems 26 with respect to the ammonia concentration at a plurality of positions measured in the section of the ammonia concentration in the flue 103. Are set individually.

  As described above, the gas component concentration distribution measuring device 110 creates an ammonia concentration distribution in the concentration measuring region in the section partitioned by the partition plate 120 of the flue 103 on the outlet side of the denitration catalyst 106, and this ammonia concentration distribution. Is output to the opening degree setting unit 109.

  According to such a denitration apparatus 105, the ammonia concentration distribution on the outlet side of the denitration catalyst 106 in the flue 103 is detected by the gas component concentration distribution measurement apparatus 110, and this detection result is output to the opening setting unit 109. . In the opening setting unit 109, the opening control of the total flow control valve 23 is performed based on the average value of the ammonia concentration, and the flow control source is based on the ammonia concentration distribution obtained by the gas component concentration distribution measuring device 110. The opening degree control of the valve 25 is performed. Thereby, the ammonia injection amount distributed to each of the plurality of ammonia supply systems 26 can be automatically adjusted according to the measured value of the ammonia concentration having a short time constant while continuing the operation of the denitration apparatus 105.

  At this time, since the opening degree control of the flow control source valve 25 is performed based on a map of a predetermined ammonia concentration and the opening degree of each flow control source valve 25, the ammonia whose total supply amount is defined by the ammonia concentration. The ammonia distribution amount for the ammonia supply system 26 is adjusted according to the opening degree of the flow control source valve 25.

  Thus, since the ammonia concentration distribution is related to the performance deterioration of the denitration catalyst 106, if the ammonia injection amount distribution control by the ammonia injection device 104 is performed based on the ammonia concentration distribution, the downstream side of the denitration device 105. It is possible to control the distribution of leaked ammonia discharged excessively. In addition, since leaked ammonia is a cause of blocking the air preheater 107, if the distribution control of the ammonia injection amount by the ammonia injection device 104 is performed based on the concentration detection, it contributes to the reduction of the blocking frequency of the air preheater 107. It becomes possible.

  According to the denitration apparatus 105 according to the present embodiment, the reducing agent injection amount distributed for each of the plurality of reducing agent supply systems according to the measured value of the ammonia concentration with a short time constant while continuing the operation of the denitration apparatus 105. Can be automatically adjusted. As a result, it is possible to extend the life of the denitration catalyst 106 and optimize the renewal of the denitration catalyst 106 by optimizing the distribution of reducing agent injection. As a result, in the denitration apparatus 105, it is possible to realize cost reduction and optimization of ammonia consumption accompanying the renewal of the denitration catalyst 106.

  In this embodiment, the gas component concentration distribution measuring device 110 is installed on the outlet side of the denitration device 105 and the ammonia concentration is measured. As shown in FIG. Gas component concentration distribution measuring devices 110 and 110 are provided on the side, and by measuring the ammonia concentration supplied to the denitration catalyst 106 and the leaked ammonia concentration after the denitration, the distribution of the leaked ammonia concentration relative to the supplied ammonia concentration may be measured. it can.

  Further, in this embodiment, the ammonia concentration is measured on the inlet side of the denitration device 105, but is not limited to the measurement of gas components on the inlet side of the denitration device 105, and the flue from the boiler outlet to the denitration device 105 In any of 103, the gas component on the inlet side may be designed.

FIG. 1C is a schematic diagram of the denitration apparatus according to the first embodiment. 1-4 is a schematic diagram of another denitration apparatus according to Embodiment 1. FIG.
In the denitration apparatus 105 of FIGS. 1-3, the probe means which has the light transmission pipe | tube 112A (112B, 112C) of the gas component concentration distribution measuring apparatus 110 so that it may be located inside the lower end part 120a and the upper end part 120b of the partition plate 120. Is arranged.
As a result, the gas component in the exhaust gas 102 can be measured inside the compartment.

Moreover, in the denitration apparatus 105 of FIG. 1-4, on the upper end part 120b side of the partition plate 120, as in FIG. 1-3, the gas component concentration distribution measuring apparatus 110 is positioned so as to be located inside the upper end part 120b. Probe means having a light transmission tube 112A (112B, 112C) is arranged.
On the other hand, on the lower end portion 120a side of the partition plate 120, the probe having the light transmission tube 112A (112B, 112C) of the gas component concentration distribution measuring apparatus 110 so as to be positioned below the lower end portion 120ab. Means are arranged.
Since the exhaust gas 102 that has passed through the denitration catalyst 106 is in a state close to a laminar flow, the state is maintained even below the lower end 120 a of the partition plate 120.
Therefore, on the lower end portion 120a side of the partition plate 120, the arrangement of the light transmitting cylinders 112A (112B, 112C) is not limited to the inner side, and even in the lower side than the lower end portion 120a, the gas in the partitioned exhaust gas Ingredients can be measured reliably.

  In this embodiment, as shown in FIG. 3, a control device 20 for controlling the semiconductor laser is installed. The control device 20 is, for example, a computer and includes a CPU, a ROM (Read Only Memory) for storing a program executed by the CPU, a RAM (Random Access Memory) functioning as a work area when each program is executed, A hard disk drive (HDD) as a capacity storage device, a communication interface for connecting to a communication network, an access unit to which an external storage device is mounted, and the like are provided. These units are connected via a bus. Furthermore, the control device 20 may be connected to an input unit such as a keyboard and a mouse and a display unit including a liquid crystal display device that displays data.

  The storage medium for storing the program executed by the CPU is not limited to the ROM. For example, other auxiliary storage devices such as a magnetic disk, a magneto-optical disk, and a semiconductor memory may be used. In the present embodiment, the control device 20 is configured to be realized by a single computer, but may be realized by a plurality of computers.

  First, the control device 20 activates the semiconductor laser transmitter 11 so as to correspond to the laser path to be measured, and after the output of the laser light is stabilized, the measurement in the laser path is performed.

  After the measurement in this laser path is completed, the measurement in the next laser path is started. In this way, measurement for each laser path is sequentially performed. Thereafter, laser light is emitted from the light transmitter 11, and the laser light absorbed by the measurement object as the laser light passes through a predetermined laser path is received by the light receiver 12.

The light receiver 12 detects the light intensity from the received light. The detected value of the laser beam is output to the control device 20. At this time, the control device 20 can associate the detection value by the light receiver 12 with the identification information (P _{1 to} P ₉ ) of the laser path corresponding to the detection value.

  The detection value and the laser path information input to the control device 20 are stored in the control device 20 in association with each other. Furthermore, the control device 20 also stores the irradiation intensity of the laser light from the light transmitter 11 during the laser irradiation. Then, the control device 20 creates a NO concentration distribution based on the stored data.

Specifically, the distance between the divided areas on each laser path, the input detection value, and the irradiation intensity of the laser light are read out, and the divided areas are obtained by using the density calculation formula represented by the above expression (2). The concentration of each measurement target is calculated. Then, the density distribution of the density measurement area is created by interpolating the density of each divided area. Thereby, the concentration distribution of the measurement object in the concentration measurement region is obtained.
The density distribution of the density measurement region thus obtained is presented to the user, for example, by being displayed on a display device (not shown) connected to the control device 20.

  And if all the ammonia concentration distribution which leaks is below a predetermined value, a driving | running will be continued on the conditions as it is. In this case, the injection amount of the ammonia injection device 104 is not adjusted.

  On the other hand, when there is a place where the concentration is high in a part of the ammonia concentration distribution, when the determination unit of the control device 20 determines, the information signal of the opening setting unit 109 is sent. In the opening setting unit 109, the opening control of the flow control source valve 25 is performed so that ammonia from the ammonia injection device 104 corresponding to the identified high ammonia concentration distribution can be injected. Thereby, the ammonia injection amount distributed to each of the plurality of ammonia supply systems 26 can be automatically adjusted according to the measured value of the ammonia concentration while continuing the operation of the denitration apparatus 105.

  As a result, by measuring each ammonia concentration distribution by the gas component concentration distribution measuring device 110 at the outlet side of the denitration device 105, it can be confirmed whether or not the denitration is uniformly performed in real time.

Nitrogen oxide (NOx) fluctuations in the exhaust gas occur when the boiler is started up, when the boiler load fluctuations or the type of fuel supplied to the boiler 101 is changed.
Therefore, using this device, when there is a load change, etc., it is determined whether nitrogen oxide is denitrated reliably by measuring the concentration distribution more frequently than the normal number of measurements. You may do it.

As mentioned above, although the present Example demonstrated adjusting the injection amount of ammonia by measuring ammonia in waste gas, this invention is not limited to this.
In the gas component measuring device, instead of measuring ammonia in exhaust gas, nitrogen oxide (NOx) in exhaust gas may be measured.

  Here, in order to measure NOx in the exhaust gas, a quantum cascade laser is used as the laser means in addition to the semiconductor laser. When measuring NO, a semiconductor element: InGaAs / InAlAs can be exemplified, and a wavelength: 5-6 μm and an output: 1 mW are used. When NO2 is measured, a semiconductor laser element: InGaAs / InAlAs can be exemplified, and a wavelength: 3 to 6 μm and an output: 1 mW are used.

  Here, when the gas component concentration distribution measuring device 110 is provided only on the outlet side of the denitration device 105 and the NO concentration in the exhaust gas when passing through the denitration device is measured, whether the NO concentration is a predetermined value or less. If it is equal to or greater than a predetermined value, an opening degree signal is sent from the opening degree setting unit 109 to the ammonia injection device 104 via the control device 20, and the ammonia injection amount distributed to each ammonia supply system 26 is determined. Adjust automatically.

  At this time, if the gas component concentration distribution measuring device 110 is installed on the inlet side and the outlet side of the denitration device 105, the NO concentration introduced into the denitration catalyst and the denitrated residual NO concentration on the outlet side are measured. Therefore, the denitration rate can be obtained simultaneously.

  A high detected value of NO concentration means that the catalytic performance of the denitration catalyst 106 has deteriorated. Therefore, each denitration catalyst 106 partitioned from the NO concentration distribution measured by the gas component concentration distribution measuring device 110 is used. It is possible to grasp the deterioration status of

FIG. 1-5 is a schematic diagram of a boiler apparatus including the denitration apparatus according to the second embodiment.
1-5 illustrates the case where the denitration catalyst is composed of two upstream denitration catalyst layers 106A and downstream denitration catalyst layers 106B, the present invention is not limited to two layers.
In this embodiment, a gas component concentration distribution measuring device (inlet) 110 is installed on the inlet side of the upstream denitration catalyst layer 106A, and the gas component is interposed between the upstream denitration catalyst layer 106A and the downstream denitration catalyst layer 106B. A concentration distribution measuring device (intermediate) 110 is installed, and a gas component concentration distribution measuring device (exit) 110 is installed on the outlet side of the downstream denitration catalyst layer 106B, and the NOx concentration distribution in the space between each layer is measured. The ammonia injection is adjusted based on the measurement result of the NO concentration distribution.

  As a result, when a plurality of layers of the denitration catalysts 106A to 106C are arranged, the NOx concentration distribution is measured for each layer, so that the denitration catalyst in which section of the denitration catalyst layer of which stage has a reduced denitration rate. The determination unit of the control device 20 can determine whether there is any.

  When it is determined that the denitration catalyst has deteriorated, it is necessary to preferentially replace the deteriorated compartmentalized denitration catalyst when replacing the denitration catalyst in the next periodic inspection.

  In addition, when the degree of deterioration of the compartmentalized denitration catalyst is determined and the amount of reducing agent supplied from the reducing agent supply means corresponding to the degraded compartment is adjusted, a solvent ( For example, an aqueous solution or the like may be sprayed to regenerate the denitration catalyst corresponding to the degraded compartment.

  Here, water may be supplied to each of a plurality (six in the illustrated example) of ammonia supply systems 26 branched from the header 24.

  In the present embodiment, ammonia and nitrogen oxide are separately measured as gas components, but the present invention is not limited to this, and ammonia and nitrogen oxide can also be measured as gas components.

  When measuring both, the type of transmitter is different, so two types of probe means are used, or an optical fiber is connected from the transmitter to the window of the transmitter tube, and this optical fiber is connected to this optical fiber. A semiconductor laser for measuring ammonia and a quantum cascade laser for measuring nitrogen oxides may be connected using a channel selector and measured alternately.

DESCRIPTION OF SYMBOLS 11 Light transmitter 12 Light receiver 15 Laser beam window 19 Seal air 20 Control apparatus 100 Boiler apparatus 101 Boiler 102 Combustion exhaust gas (exhaust gas)
DESCRIPTION OF SYMBOLS 103 Flue 104 Ammonia injection apparatus 105 Denitration apparatus 106A, 106B, 106C Denitration catalyst 110 Gas component concentration distribution measuring apparatus

Claims (9)

Reducing agent supply means for supplying a reducing agent into the combustion exhaust gas;
A denitration apparatus including a denitration catalyst that denitrates nitrogen oxide (NOx) in the exhaust gas containing the reducing agent;
A plurality of probe means for measuring a gas component concentration distribution in the exhaust gas in a region corresponding to a denitration catalyst that is provided on at least one of the inlet side or the outlet side of the denitration device and orthogonal to the gas flow of the denitration device. Having a gas component concentration distribution measuring device for measuring by laser measuring means,
An exhaust gas denitration system, wherein a gas component concentration distribution is obtained from a measurement result of the gas component concentration distribution measuring device. In claim 1,
The exhaust gas denitration system, wherein the gas component is either one or both of ammonia (NH ₃ ) and nitrogen oxide (NOx). In claim 2,
When the gas component is ammonia, from the measurement result of the gas component concentration distribution measuring device, obtain the ammonia concentration distribution,
From the obtained ammonia concentration distribution, a judging means for judging a section where the leak ammonia concentration is a predetermined value or more,
An exhaust gas denitration system comprising adjusting means for adjusting a reducing agent supply amount from a reducing agent supply means corresponding to the determined section. In claim 2,
When the gas component is nitrogen oxide, from the measurement result of the gas component concentration distribution measuring device, obtain the nitrogen oxide concentration distribution,
From the obtained NO concentration distribution, a judging means for judging a section where the NO concentration is not sufficient for denitration with a predetermined value or more;
An exhaust gas denitration system comprising: adjusting means for adjusting a reducing agent supply amount from a reducing agent supply means corresponding to the determined insufficient denitration section. In claim 4,
A determination means for determining a denitration rate of the denitration catalyst divided from the obtained NO concentration distribution, and judging a degree of deterioration of the denitration catalyst;
Exhaust gas denitration comprising adjusting means for spraying water together with ammonia supply or separately from ammonia supply when adjusting the reducing agent supply amount from the reducing agent supply means corresponding to the deteriorated compartment system. In any one of Claims 1 thru | or 5,
The probe means includes a light-transmitting tube that passes laser light;
An exhaust gas denitration system characterized in that a part of the light transmission cylinder is divided by a predetermined distance and has a measurement region exposed to a measurement field. In claim 6,
The exhaust gas denitration system, wherein the measurement region is different along the longitudinal direction of the light transmission tube and is located in a part of the partitioned region. Using the exhaust gas denitration system according to any one of claims 1 to 7,
Determine the degree of deterioration of the denitration catalyst that has been partitioned,
When adjusting the reducing agent supply amount from the reducing agent supply means corresponding to the degraded compartment, the solvent is sprayed together with the ammonia supply or separately from the ammonia supply,
A method for regenerating an exhaust gas denitration apparatus, comprising regenerating a denitration catalyst corresponding to a deteriorated section. Using the exhaust gas denitration system according to any one of claims 1 to 7,
Determine the degree of deterioration of the denitration catalyst that has been partitioned,
A catalyst replacement method for an exhaust gas denitration apparatus, wherein a denitration catalyst in a degraded section is replaced at the time of inspection.

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