JP2017113697A - Reductant pouring amount sharing control method, denitration method and denitration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reductant pouring amount sharing control method on each pouring part in order to suppress a local concentration rise of unreacted reductant on a denitration reactor outlet, and to provide a denitration method and a denitration system.SOLUTION: A plurality of pouring parts for pouring reductant into exhaust gas and a denitration reactor 4 arranged on the downstream side are provided. A denitration system of exhaust gas includes: a step of obtaining a reductant flow model which exhibits correlation between a sharing rate parameter from each of a plurality of pouring parts for pouring total amount of the reductant and a concentration of the reductant of the inlet 4a side on each of a plurality of sections provided by dividing a cross-section of the denitration reactor 4 vertical to an exhaust gas flow direction; a step of obtaining a denitration reaction model which exhibits correlation between the concentration of the reductant on the inlet 4a side of the denitration reactor 4 and a concentration on the outlet 4b side; a step of estimating the concentration of the reductant on the outlet side in each section; and a step of calculating a recommended value of the sharing rate parameter.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a denitration technology for exhaust gas, and when reducing agent is dispersed and injected into exhaust gas from a plurality of injection units (for example, nozzles), the reducing agent injection amount sharing for controlling the injection amount sharing of the reducing agent in each injection unit is disclosed. The present invention relates to a control method, a denitration method, and a denitration system.

Conventionally, a denitration technique for removing nitrogen oxide (NOx) in exhaust gas with a reducing agent is known. In a typical denitration apparatus, a reducing agent (for example, NH ₃ ) is blown into the exhaust gas from a plurality of nozzles installed in the flue of the exhaust gas, and in a reactor provided on the downstream side, for example, nitrogen oxidation is performed in the presence of a catalyst. It promotes the reduction reaction of substances and decomposes nitrogen oxides in exhaust gas into water and nitrogen.

  In such a denitration device, the distribution of the amount of reducing agent injected in the flue is one of the factors that determine the denitration efficiency. That is, in the denitration apparatus, in order to prevent the unreacted reducing agent from leaking to the downstream side, the reducing agent having an appropriate molar ratio with respect to the nitrogen oxide in the exhaust gas is usually supplied. It is required to control the injection amount sharing of the reducing agent in the plurality of nozzles so that the fixed amount of the reducing agent appropriately reacts with the nitrogen oxides in the exhaust gas and the leakage amount of the reducing agent is suppressed.

For example, Patent Documents 1 and 2 disclose a denitration apparatus equipped with an ammonia injection device and a denitration reactor provided in an exhaust gas duct.
More specifically, the ammonia injection device in Patent Document 1 is configured so that the NOx concentration at the outlet of the denitration reactor in each section formed by dividing the exhaust gas duct into a plurality of parts is uniformized. The injection amount is adjusted independently.
Patent Document 2 describes that a denitration reactor (denitration catalyst) is divided into a plurality of sections in a plane orthogonal to the exhaust gas flow, and the concentration of NH ₃ or NOx in the exhaust gas in a region corresponding to each section is measured. Has been. As an example, when the ammonia concentration is measured, it is also described that the supply amount of the reducing agent is adjusted by a flow control source valve for a section having a leak ammonia concentration of a predetermined value or more. Furthermore, in this case, it is also described that the reducing agent supply amount is adjusted using a control map indicating a correlation between a predetermined ammonia concentration and the opening degree of each flow control source valve.

JP-A-10-216475 JP 2014-94355 A

By the way, in the above-described denitration apparatus, the leakage amount of the unreacted reducing agent may partially increase due to the secular change of the denitration efficiency. For example, when a denitration catalyst is used as a denitration reactor, if there is a difference in the deterioration rate of each part of the denitration catalyst, the denitration efficiency in the denitration reactor varies, and the amount of unreacted reducing agent leak increases locally. End up.
In addition to these circumstances, the amount of leakage of unreacted reducing agent may increase due to the flow of exhaust gas. Generally, there is a distance between the reducing agent injection nozzle provided in the exhaust gas duct and the denitration reactor, and the exhaust gas duct may be bent. Therefore, due to the flow of exhaust gas from the nozzle to the denitration reactor, the concentration distribution of the reducing agent at the time of reducing agent injection changes when it reaches the denitration reactor. Therefore, even if the reducing agent is uniformly injected into the exhaust gas duct, the concentration of the reducing agent flowing into the denitration reactor is not always uniform, and the leakage amount of the unreacted reducing agent may locally increase. possible.
When the leak amount of the unreacted reducing agent locally increases, acidic ammonium sulfate adheres to equipment (for example, an air preheater in a boiler) located on the downstream side of the denitration device, and the equipment deteriorates or malfunctions (for example, an air preheater). Blockage).

In this regard, Patent Document 1 describes that the ammonia injection amount in each section of the exhaust gas duct is adjusted, but this is a specific example for suppressing a local concentration increase of leaked ammonia on the outlet side of the denitration reactor. The method is not described.
On the other hand, Patent Document 2 describes using a control map indicating a correlation between the ammonia concentration and the opening degree of each flow control source valve as a specific ammonia injection amount adjusting method according to the ammonia concentration. However, in this method, there is a time lag until the effect of changing the setting of the flow control main valve opening appears as a change in the ammonia concentration distribution at the denitration reactor outlet, and the ammonia concentration distribution at the denitration reactor outlet is within the control range. There is a problem that it is difficult to fit surely.

  An object of at least some embodiments of the present invention is to obtain an appropriate injection volume sharing of the reducing agent in each injection section in order to suppress a local concentration increase of the unreacted reducing agent at the denitration reactor outlet. It is intended to provide a reducing agent injection amount sharing control method, a denitration method, and a denitration system.

(1) The reducing agent injection amount sharing control method according to at least some embodiments of the present invention includes:
A plurality of injection parts for injecting a reducing agent into the exhaust gas; and a denitration reactor disposed downstream of the injection part, and the nitrogen is produced by a reaction between nitrogen oxides in the exhaust gas and the reducing agent. A method of adjusting the injection share of each injection portion in a denitration apparatus configured to decompose oxide,
A cross-section of the denitration reactor orthogonal to the exhaust gas flow direction, and a share ratio parameter of each injection part correlated with the ratio of the injection quantity of the reducing agent from each of the plurality of injection parts to the total injection quantity of the reducing agent Obtaining a reducing agent flow model showing a correlation with the concentration of the reducing agent on the inlet side of the denitration reactor in each of a plurality of sections obtained by dividing
Obtaining a denitration reaction model showing a correlation between the concentration of the reducing agent on the inlet side of the denitration reactor and the concentration of the reducing agent on the outlet side of the denitration reactor for each of the compartments;
Using the reducing agent flow model and the denitration reaction model to estimate the concentration of the reducing agent on the outlet side in each section from the candidate values of the sharing ratio parameter;
Calculating a recommended value of the sharing ratio parameter based on an estimated value of the concentration of the reducing agent;
Is provided.

In the above method (1), the concentration of the reducing agent on the outlet side in each section is estimated from the candidate values of the sharing ratio parameter using the two models of the reducing agent flow model and the denitration reaction model. Yes. Here, the reducing agent flow model is a model showing a correlation between the share ratio parameter of each injection portion and the concentration of the reducing agent on the inlet side of the denitration reactor in each of the plurality of sections. On the other hand, the denitration reaction model is a model showing the correlation between the concentration of the reducing agent on the inlet side of the denitration reactor and the concentration of the reducing agent on the outlet side for each section of the denitration reactor.
According to this method, after considering the diffusion state of the reducing agent in the exhaust gas from the injection part to the denitration reactor inlet and the denitration rate in the denitration reactor, for each candidate value of the sharing rate parameter, The concentration of the reducing agent on the outlet side in each compartment can be estimated.
Further, the recommended value of the sharing ratio parameter is calculated based on the estimated value of the concentration of the reducing agent. As a result, it is possible to obtain a recommended value of an appropriate sharing ratio parameter that can avoid a local concentration increase of the unreacted reducing agent on the outlet side of the denitration reactor.

If the injection amount sharing of the injection unit is controlled using the appropriate share ratio parameter thus obtained, the injection amount control is performed based on the nitrogen oxide concentration or the unreacted reducing agent concentration on the outlet side of the denitration reactor. Compared to simple feedback control, the local increase of the unreacted reducing agent can be more effectively suppressed without causing a time lag.
Furthermore, it is possible to avoid the troubles associated with the generation of acidic ammonium sulfate in the equipment provided on the downstream side of the denitration device, and it is possible to contribute to the continuous operation of the plant equipped with the denitration device.
In the present specification, the “sharing ratio parameter” indicates the ratio (sharing ratio) of the reducing agent injection amount from the target nozzle to the total amount of reducing agent injection supplied into the exhaust gas from a plurality of injection portions. It is a parameter. For example, the share rate parameter may be the share rate of the injection unit itself, or other parameters correlated with the share rate, such as the opening of a valve for adjusting the amount of reducing agent injected in the injection unit. It may be.

(2) In some embodiments, in the method of (1) above,
In the step of calculating the recommended value of the sharing ratio parameter, the distribution of the estimated value of the reducing agent concentration on the outlet side of the denitration reactor in the plurality of compartments and the reducing agent on the outlet side of the denitration reactor Based on an index indicating a deviation from the target concentration distribution, a correction amount from the candidate value to the recommended value of the sharing ratio parameter is obtained using the reducing agent flow model and the denitration reaction model.

  According to the above method (2), the reducing agent flow model and the denitration reaction model are also used in the step of calculating the recommended value of the sharing ratio parameter, and the estimated concentration of the reducing agent at the outlet side of the denitration reactor is calculated. Based on an index indicating the difference between the distribution and the target concentration distribution, the correction amount from the candidate value of the sharing ratio parameter to the recommended value is obtained. Thereby, the reducing agent concentration on the outlet side of the denitration reactor can be made closer to the target concentration distribution.

(3) In one embodiment, in the method of (2) above,
The index indicating the deviation is a deviation amount of the estimated value from the concentration management range of the reducing agent on the outlet side of the denitration reactor.

  According to the above method (3), it is possible to obtain a recommended value such that the concentration distribution of the reducing agent does not deviate from the concentration management range of the reducing agent, and to more appropriately control the injection amount sharing of the reducing agent. it can.

(4) In some embodiments, in any of the above methods (1) to (3),
Measuring the concentration of the reducing agent on the outlet side of the denitration reactor in each compartment;
Correcting the denitration reaction model based on the deviation between the estimated value and the measured value of the concentration of the reducing agent on the outlet side in each compartment;
Is further provided.

  In the method (4), the denitration reaction model is corrected based on the deviation between the estimated value and the measured value of the concentration of the reducing agent on the outlet side in each section. Thereby, it is possible to minimize the influence of the reduction in the denitration efficiency on the estimation of the reducing agent concentration, and to calculate the recommended value of the sharing rate parameter with high accuracy.

(5) In some embodiments, in any of the above methods (1) to (4),
The share ratio parameter is a share ratio indicating the ratio of the injection amount of each injection portion to the total injection amount of the reducing agent.

  According to the method of (5) above, by using the sharing rate itself indicating the ratio of the injection amount of each injection portion to the total injection amount of the reducing agent as the sharing rate parameter, the calculation load is calculated when calculating the recommended value of the sharing rate parameter. Can be reduced.

(6) In one embodiment, in the method of (5) above,
The method further includes the step of calculating a recommended value of the opening of the valve for adjusting the injection amount of the reducing agent from the injection unit from the recommended value of the sharing rate of each injection unit as the sharing rate parameter.

(7) In some embodiments, in the method according to any one of (1) to (4) above,
The share ratio parameter is an opening of a valve for adjusting the injection amount of the reducing agent from the injection portion.

  According to the configuration of (6) or (7) above, since the valve opening degree directly related to the adjustment of the injection amount of the reducing agent is used as the sharing rate parameter of the injection unit, the sharing rate is recommended. The procedure from the value to the injection control of the reducing agent can be simplified.

(8) A method of operating the denitration apparatus according to at least some embodiments of the present invention includes:
A plurality of injection parts for injecting a reducing agent into the exhaust gas; and a denitration reactor disposed downstream of the injection part, and the nitrogen is produced by a reaction between nitrogen oxides in the exhaust gas and the reducing agent. A method of operating a denitration apparatus configured to decompose oxide,
The method includes a step of adjusting the injection sharing rate of each injection unit based on the recommended value of the sharing rate parameter obtained by the reducing agent injection amount sharing control method according to any one of (1) to (7).

According to the above method (8), since the injection amount sharing of each injection portion is adjusted based on the recommended value of the appropriate sharing rate parameter acquired by the above-described reducing agent injection amount sharing control method, The local increase of the unreacted reducing agent can be suppressed more effectively.
Therefore, it is possible to avoid the trouble associated with the generation of acidic ammonium sulfate in the equipment provided on the downstream side of the denitration device, and it is possible to contribute to the continuous operation of the plant equipped with the denitration device.

(9) A denitration system according to at least some embodiments of the present invention includes:
A plurality of injection parts for injecting the reducing agent into the exhaust gas;
A denitration reactor disposed downstream of the injection portion and configured to decompose the nitrogen oxides by a reaction between the nitrogen oxides in the exhaust gas and the reducing agent;
For each of the injection units, a sharing rate adjustment unit for calculating a recommended value of a sharing rate parameter correlated with the ratio of the injection amount of the injection unit to the total injection amount of the reducing agent, and
The sharing ratio adjustment unit
Correlation between the sharing ratio parameter of each injection portion and the concentration of the reducing agent on the inlet side of the denitration reactor in each of a plurality of sections obtained by dividing a cross section of the denitration reactor orthogonal to the exhaust gas flow direction To obtain a reducing agent flow model
For each of the compartments, obtain a denitration reaction model showing a correlation between the concentration of the reducing agent on the inlet side of the denitration reactor and the concentration of the reducing agent on the outlet side of the denitration reactor;
Using the reducing agent flow model and the denitration reaction model, from the candidate values of the sharing ratio parameter, estimate the concentration of the reducing agent on the outlet side in each section,
The recommended value of the sharing ratio parameter is calculated based on the estimated value of the concentration of the reducing agent.

According to the configuration of (9) above, the concentration of the reducing agent on the outlet side in each section is estimated from the candidate values of the sharing ratio parameter using the two models of the reducing agent flow model and the denitration reaction model. It has become.
According to this configuration, after considering the diffusion state of the reducing agent in the exhaust gas from the injection part to the denitration reactor inlet and the denitration rate in the denitration reactor, for each candidate value of the sharing rate parameter, The concentration of the reducing agent on the outlet side in each compartment can be estimated.
Further, the recommended value of the sharing ratio parameter is calculated based on the estimated value of the concentration of the reducing agent. As a result, it is possible to obtain a recommended value of an appropriate sharing ratio parameter that can avoid a local concentration increase of the unreacted reducing agent on the outlet side of the denitration reactor.
If the injection amount sharing of the injection unit is controlled using the appropriate share ratio parameter thus obtained, the injection amount control is performed based on the nitrogen oxide concentration or the unreacted reducing agent concentration on the outlet side of the denitration reactor. Compared to simple feedback control, the local increase of the unreacted reducing agent can be more effectively suppressed without causing a time lag.
Furthermore, it is possible to avoid the troubles associated with the generation of acidic ammonium sulfate in the equipment provided on the downstream side of the denitration device, and it is possible to contribute to the continuous operation of the plant equipped with the denitration device.

(10) In some embodiments, in the configuration of (9) above,
The sharing ratio adjusting unit is configured to discriminate between the distribution of the estimated value of the concentration of the reducing agent on the outlet side of the denitration reactor in the plurality of sections and the target concentration distribution of the reducing agent on the outlet side of the denitration reactor. On the basis of the index indicating, a correction amount from the candidate value to the recommended value of the sharing ratio parameter is obtained using the reducing agent flow model and the denitration reaction model.

  According to the configuration of (10) above, even when the recommended value of the sharing ratio parameter is calculated, the sharing ratio adjustment unit uses the reducing agent flow model and the denitration reaction model, and the reducing agent on the outlet side of the denitration reactor. Based on an index indicating the difference between the distribution of the estimated density value and the target density distribution, the correction amount from the candidate value of the sharing ratio parameter to the recommended value is obtained. Thereby, the reducing agent concentration on the outlet side of the denitration reactor can be made closer to the target concentration distribution.

(11) In some embodiments, in the configuration described in (10) above,
The index indicating the deviation is a deviation amount of the estimated value from the concentration management range of the reducing agent on the outlet side of the denitration reactor.

  According to the configuration of (11) above, it is possible to obtain a recommended value such that the concentration distribution of the reducing agent does not depart from the concentration management range of the reducing agent, and to more appropriately control the injection amount sharing of the reducing agent. it can.

(12) In some embodiments, in any one of the above configurations (9) to (11),
The apparatus further includes a model correction unit that corrects the denitration reaction model based on a deviation between the measured value of the concentration of the reducing agent on the outlet side of the denitration reactor in each section and the estimated value.

  According to the configuration of (12) above, the denitration reaction model is corrected based on the deviation between the estimated value and the measured value of the concentration of the reducing agent on the outlet side in each section. Thereby, it is possible to minimize the influence of the reduction in the denitration efficiency on the estimation of the reducing agent concentration, and to calculate the recommended value of the sharing rate parameter with high accuracy.

(13) In some embodiments, in any one of the above configurations (9) to (12),
The share ratio parameter is a share ratio indicating the ratio of the injection amount of each injection portion to the total injection amount of the reducing agent.

  According to the configuration of (13) above, by using the sharing rate itself indicating the ratio of the injection amount of each injection portion to the total injection amount of the reducing agent as the sharing rate parameter, the calculation load is calculated when calculating the recommended value of the sharing rate parameter. Can be reduced.

(14) In some embodiments, in any one of the configurations (9) to (13),
The share rate adjusting unit is configured to obtain a recommended value of a valve opening for adjusting the injection amount of the reducing agent from the injection unit from the recommended value of the share rate parameter of each injection unit as the share rate parameter. Configured to calculate.

(15) In some embodiments, in any one of the above configurations (9) to (12),
The share ratio parameter is an opening of a valve for adjusting the injection amount of the reducing agent from the injection portion.

  According to the configuration of the above (14) or (15), the valve opening degree directly related to the adjustment of the injection amount of the reducing agent is used as the share ratio parameter of the injection section. The procedure from the value to the injection control of the reducing agent can be simplified.

According to at least one embodiment of the present invention, taking into account the diffusion state of the reducing agent in the exhaust gas from the injection section to the denitration reactor inlet and the denitration rate in the denitration reactor, For each candidate value, the concentration of the reducing agent on the outlet side in each section can be estimated. Further, the recommended value of the sharing ratio parameter is calculated based on the estimated value of the concentration of the reducing agent. As a result, it is possible to obtain a recommended value of an appropriate sharing ratio parameter that can avoid a local concentration increase of the unreacted reducing agent on the outlet side of the denitration reactor.
If the injection amount sharing of the injection portion is controlled using the appropriate share ratio parameter obtained in this way, the local increase of the unreacted reducing agent can be more effectively suppressed.
Furthermore, it is possible to avoid the troubles associated with the generation of acidic ammonium sulfate in the equipment provided on the downstream side of the denitration device, and it is possible to contribute to the continuous operation of the plant equipped with the denitration device.

It is a figure showing roughly the composition of the denitration system concerning one embodiment. It is a schematic diagram (AA line cross section of FIG. 1) which shows the cross section of the denitration reactor in one Embodiment. It is a flowchart which shows the reducing agent injection amount sharing control method which concerns on one Embodiment. It is a flowchart which shows the reducing agent injection amount sharing control method which concerns on other embodiment.

  Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.

  First, with reference to FIG.1 and FIG.2, the whole structure of the denitration system 1 which concerns on some embodiment is demonstrated. FIG. 1 is a diagram schematically illustrating a configuration of a denitration system 1 according to an embodiment. FIG. 2 is a schematic diagram (cross section taken along line AA in FIG. 1) showing a cross section of the denitration reactor 4 in one embodiment.

  As illustrated in FIG. 1, a denitration system 1 according to some embodiments includes a plurality of nozzles (injection units) 2 for injecting a reducing agent into exhaust gas and downstream of the plurality of nozzles 2. The denitration reactor 4 and the sharing rate adjustment unit 8 for calculating the recommended value of the sharing rate parameter for each nozzle 2 are provided.

  Here, the sharing ratio parameter is a parameter correlated with the ratio of the injection amount of the nozzle 2 to the total injection amount of the reducing agent for each of the plurality of nozzles 2. In other words, the sharing ratio parameter is a parameter indicating the ratio (sharing ratio) of the amount of reducing agent injected from the target nozzle 2 to the total amount of reducing agent injected from the plurality of nozzles 2 into the exhaust gas. For example, the share ratio parameter may be the share ratio itself of the nozzle (target nozzle) 2 or may be correlated with the share ratio, such as the opening of a valve for adjusting the reducing agent injection amount in the nozzle 2. It may be some other parameter.

In the embodiment illustrated in FIG. 1, the denitration system 1 is configured to denitrate exhaust gas from the boiler 10 of the power plant. However, the exhaust gas to be treated by the denitration system 1 is not limited to the exhaust gas from the boiler 10.
The denitration system 1 is provided in an exhaust gas duct 12 disposed between a boiler 10 and an air preheater 16. Specifically, the denitration system 1 has a configuration in which a plurality of nozzles 2, a denitration reactor 4, a reducing agent concentration detector 6, and a NOx concentration detector 18 are sequentially provided from the upstream side of the exhaust gas duct 12. It has become.
In addition, as described above, the denitration system 1 further includes a sharing ratio adjusting unit 8 for calculating a recommended value of the sharing ratio parameter for each nozzle 2.

  The plurality of nozzles 2 are configured to inject a reducing agent into the exhaust gas, and in a cross section orthogonal to the exhaust gas flow direction of the exhaust gas duct 12 (for example, a cross section orthogonal to the extending direction of the exhaust gas duct 12). A plurality are provided. Each nozzle 2 may be configured such that the injection amount of the reducing agent can be adjusted independently. Each nozzle 2 may be provided with a valve (not shown) for adjusting the injection amount of the reducing agent. In this case, the valve may be configured to be manually controlled or may be configured to be automatically controlled. Examples of the reducing agent include ammonia and urea. The total amount of reducing agent supplied from the plurality of nozzles 2 is determined according to the amount of NOx (for example, estimated value) in the exhaust gas.

  The denitration reactor 4 is a place where main denitration reaction is performed. For example, a denitration catalyst is supported and denitration is performed by a selective catalytic denitration method. However, the configuration of the denitration reactor 4 is not limited to this. For example, as another embodiment, the denitration reactor 4 may be configured to perform a radical denitration method using a radical reaction, or may be configured to promote a reduction reaction by adding a radical reaction in a selective catalytic denitration method. There may be.

The reducing agent concentration detector 6 is configured to detect the concentration of the reducing agent (unreacted reducing agent). The reducing agent concentration detector 6 may be configured to detect the reducing agent concentration corresponding to each section of the denitration reactor 4.
The NOx concentration detector 18 is configured to detect the concentration of nitrogen oxides (hereinafter referred to as NOx) in the exhaust gas. The NOx concentration detection unit 18 may be configured to detect the NOx concentration corresponding to each section of the denitration reactor 4.
The reducing agent concentration detection unit 6 or the NOx concentration detection unit 18 may detect each concentration by manual analysis, or may automatically detect using, for example, a laser gas analyzer. In addition, a laser type gas analyzer measures the density | concentration of a specific substance from the light absorption amount of a specific wavelength by irradiating a laser beam in waste gas.
The reducing agent concentration detection unit 6 or the NOx concentration detection unit 18 is selectively installed, and the denitration system 1 may have a configuration in which these detection units are not installed.

Next, the sharing ratio adjustment unit 8 will be described in detail.
The share ratio adjusting unit 8 is divided into a plurality of sections k (reference numerals 4-1 and 4-2 in FIG. 2) obtained by dividing the cross section of the denitration reactor 4 orthogonal to the share ratio parameter of each nozzle 2 and the exhaust gas flow direction. ,..., 4-k), a reducing agent flow model showing a correlation with the concentration of the reducing agent on the inlet 4a side of the denitration reactor 4 is obtained, and the inlet 4a side of the denitration reactor 4 is obtained for each of the sections. A denitration reaction model showing a correlation between the concentration of the reducing agent of the catalyst and the concentration of the reducing agent on the outlet 4b side of the denitration reactor 4, and using the reducing agent flow model and the denitration reaction model, candidate values of the share ratio parameter From this, the concentration of the reducing agent on the outlet 4b side in each section is estimated, and the recommended value of the sharing ratio parameter is calculated based on the estimated value of the concentration of the reducing agent.

Here, the reducing agent flow model is a model showing a correlation between the sharing ratio parameter of each nozzle 2 and the concentration of the reducing agent on the inlet 4a side of the denitration reactor 4 in each of the plurality of sections.
More specifically, the reducing agent flow model includes the reducing agent concentration B (k) supplied to each section k (reference numeral 4-k shown in FIG. 2) when the denitration reactor 4 is divided into a plurality of sections. FIG. 5 is a model of the correlation with the injection amount of the reducing agent supplied from a plurality of nozzles 2.
Since the total injection amount of the reducing agent is determined according to the NOx amount in the exhaust gas acquired in advance, the injection amount sharing of the reducing agent from each nozzle 2 is set so as to maintain the total injection amount of the reducing agent. Is done. That is, the sum of the reducing agent injection amounts from all the nozzles 2 matches the total reducing agent injection amount. Therefore, if the injection amount sharing ratio of the reducing agent shared by each nozzle j is A (j), ΣA (j) = 1.0. The reducing agent flow model represents the correlation between the reducing agent injection amount sharing ratio A (j) and the reducing agent concentration distribution B (k) on the inlet 4a side of the denitration reactor 4.
Note that the amount of NOx in the exhaust gas can be estimated from, for example, the type of fuel in the boiler 10, the combustion state (including the combustion temperature), etc., if the exhaust gas is from the boiler 10. Alternatively, the NOx amount in the exhaust gas may be an actual NOx detection value on the upstream side of the denitration system 1.

In one embodiment, the reducing agent flow model measures the amount of reducing agent at the inlet 4a or outlet 4b of the denitration reactor 4 by performing a test to increase or decrease the injection ratio of reducing agent in each nozzle 2 individually. The relationship may be expressed by a mathematical model. As an example, as shown in FIG. 2, there are nine 3 × 3 sections k of the denitration reactor 4, and although the illustration is omitted, the nozzle 2 also has three stages and three rows (9 places) in the exhaust gas duct 12. May be expressed as a coefficient matrix of 9 rows and 9 columns. In this case, if the exhaust gas flows uniformly, it becomes a diagonal matrix.
As another embodiment, in order to express in more detail the correlation between the sharing ratio parameter of each nozzle 2 and the concentration of the reducing agent on the inlet 4a side of the denitration reactor 4 in each of the plurality of sections, a reducing agent flow model is used. The flow analysis calculation (CFD) may be used in the creation.

On the other hand, the denitration reaction model is a reducing agent on the inlet 4a side of the denitration reactor 4 for each of the sections k of the denitration reactor 4 (see reference numerals 4-1, 4-2,..., 4-k in FIG. 2). Is a model showing a correlation between the concentration of the reducing agent and the concentration of the reducing agent on the outlet 4b side.
For example, when the denitration reactor 4 is configured to carry a denitration catalyst, in each section k of the denitration reactor 4, the molar ratio of the reducing agent and NOx reaching the inlet 4a and the denitration catalyst in the denitration reactor 4 Depending on the characteristics, the reducing agent (unreacted reducing agent) on the outlet 4b side and the NOx concentration are determined.
Here, the characteristics of the denitration catalyst can be expressed by the following denitration efficiency.
Denitration rate = (1-denitration reactor outlet NOx concentration / denitration reactor inlet concentration) × 100%
Molar ratio = Denitration rate / 100 + Denitration reactor outlet reducing agent concentration / Denitration reactor inlet NOx concentration Based on these, the reducing agent concentration X (k) at the outlet 4b of the denitration reactor 4 and the reduction at the inlet 4a The relationship of the dose B (k) is a denitration reaction model.

In the above method, the concentration of the reducing agent on the outlet 4b side in each section is estimated from the candidate values of the sharing ratio parameter using the two models of the reducing agent flow model and the denitration reaction model.
Specifically, when the reducing agent injection amount of the nozzle 2 has a certain distribution (A (j), j = 1, 2,...), That is, when the injection sharing rate of each nozzle 2 is set to a candidate value, denitration is performed. Reducing agent concentration distribution estimated value (B (k), k = 1, 2,...) On the inlet 4a side of the reactor 4 and reducing agent concentration distribution estimated value (X (k), k) on the outlet 4b side of the denitration reactor 4 k = 1, 2,...) can be calculated using two models, a reducing agent flow model and a denitration reaction model.

According to this method, after considering the diffusion state of the reducing agent in the exhaust gas between the nozzle 2 and the inlet 4a of the denitration reactor 4 and the denitration rate in the denitration reactor 4, candidates for the share rate parameter For each value, the concentration of the reducing agent on the outlet 4b side in each section k can be estimated.
Further, the recommended value of the sharing ratio parameter is calculated based on the estimated value of the concentration of the reducing agent. Thereby, it is possible to obtain a recommended value of an appropriate sharing ratio parameter that can avoid a local concentration increase of the unreacted reducing agent on the outlet 4b side of the denitration reactor 4.

If the injection amount sharing of the nozzle 2 is controlled using the appropriate share ratio parameter thus obtained, the injection amount control is performed based on the nitrogen oxide concentration or the unreacted reducing agent concentration on the outlet 4b side of the denitration reactor 4. Compared to such simple feedback control, the local increase of the unreacted reducing agent can be more effectively suppressed without causing a time lag.
Further, it is possible to avoid the trouble caused by the generation of acidic ammonium sulfate in the equipment provided on the downstream side of the denitration system 1, and to contribute to the continuous operation of the plant equipped with the denitration system 1.

  When the denitration system 1 includes the reducing agent concentration detection unit 6, the sharing ratio adjustment unit 8 distributes the estimated value of the reducing agent concentration X (k) on the outlet 4 b side of the denitration reactor 4 in a plurality of sections. And an index indicating the deviation dX (k) between the reducing agent target concentration distribution on the outlet 4b side of the denitration reactor 4, and using the reducing agent flow model and the denitration reaction model, The correction amount to the recommended value may be obtained.

  According to the above configuration, even when the recommended value of the sharing rate parameter is calculated, the sharing rate adjusting unit 8 uses the reducing agent flow model and the denitration reaction model, and the reducing agent on the outlet 4b side of the denitration reactor 4 is used. A correction amount from the candidate value of the sharing ratio parameter to the recommended value is obtained based on an index indicating a deviation between the distribution of the density estimated value and the target density distribution. Thereby, the reducing agent concentration on the outlet 4b side of the denitration reactor 4 can be made closer to the target concentration distribution.

In this case, the indicator indicating the deviation may be a deviation amount of the estimated value from the reducing agent concentration management range on the outlet 4b side of the denitration reactor 4.
This makes it possible to obtain a recommended value so that the concentration distribution of the reducing agent does not deviate from the concentration management range of the reducing agent, and it is possible to more appropriately control the injection amount sharing of the reducing agent.

More specifically, since a high concentration of the reducing agent on the outlet 4b side of the denitration reactor 4 may affect downstream equipment (for example, the air preheater 16) of the denitration system 1, generally, denitration is performed. The concentration management range of the reducing agent on the outlet 4b side of the reactor 4 is set. Therefore, if a section in which the reducing agent concentration on the outlet 4b side of the denitration reactor 4 exceeds the concentration management range is generated, it is necessary to lower the reducing agent concentration for the section. For this purpose, as described above, the amount of change dB (k) of the reducing agent on the inlet 4a side of the denitration reactor 4 can be calculated by calculating back the denitration reaction model. Further, the injection ratio of the reducing agent necessary for the reducing agent change amount dB (k) can be calculated by calculating back the reducing agent flow model.
Through the above processing, a new recommended value of the injection rate sharing ratio is acquired, and if the injection amount of the reducing agent is manually adjusted or changed to the recommended value by the injection amount control device, the denitration reactor 4 on the outlet 4b side The reducing agent concentration can be kept below the concentration control range.
Moreover, when calculating the amount of change in the reducing agent concentration distribution on the inlet 4a side of the denitration reactor 4, the section where the reducing agent concentration on the outlet 4b side is maximized is lowered instead of the section exceeding the concentration management range. You may do it. Thereby, it becomes possible to adjust the reducing agent injection amount so that the reducing agent concentration distribution at the outlet 4b of the denitration reactor 4 approaches a uniform by repeating the adjustment.

In one embodiment, the denitration system 1 has a deviation E (k) between the measured value X ₀ (k) and the estimated value X (k) of the reducing agent concentration on the outlet 4b side of the denitration reactor 4 in each section k. Is further provided with a model correction unit 9 for correcting the denitration reaction model. For example, when the denitration reactor 4 is configured to carry a denitration catalyst, the model correction unit 9 may correct the catalyst efficiency η _k of the denitration catalyst in the corresponding section k.

According to the above configuration, the denitration reaction model is corrected based on the deviation E (k) between the estimated value X (k) of the concentration of the reducing agent on the outlet 4b side and the measured value X ₀ (k) in each section. It is like that. Thereby, it is possible to minimize the influence of the reduction in the denitration efficiency on the estimation of the reducing agent concentration, and to calculate the recommended value of the sharing rate parameter with high accuracy.

  In one embodiment, the sharing rate parameter is a sharing rate indicating the ratio of the injection amount of each nozzle 2 to the total injection amount of the reducing agent.

  According to the above configuration, by using the share rate itself indicating the ratio of the injection amount of each nozzle 2 to the total injection amount of the reducing agent as the share rate parameter, the calculation load is reduced when calculating the recommended value of the share rate parameter. Can do.

In one embodiment, the sharing rate adjustment unit 8 uses the recommended value of the sharing rate parameter of each nozzle 2 as the sharing rate parameter, and the recommended value of the valve opening for adjusting the injection amount of the reducing agent from the nozzle 2. Is configured to calculate.
In this case, the share ratio parameter may be the opening of a valve for adjusting the amount of reducing agent injected from the nozzle 2.

  According to the above configuration, since the valve opening directly related to the adjustment of the reducing agent injection amount is used as the sharing rate parameter of the nozzle 2, the reducing agent injection amount control is performed from the recommended value of the sharing rate. The procedure up to can be simplified.

  Next, with reference to FIG. 3 and FIG. 4, the reducing agent injection amount sharing control method according to some embodiments will be described. In the following description, the above-described reference numerals in FIG. 1 are used as appropriate.

  As illustrated in FIGS. 3 and 4, the reducing agent injection amount sharing control method according to some embodiments includes a reducing agent flow model acquisition step (S1), a denitration reaction model acquisition step (S2), and a denitration method. A reactor outlet side concentration calculating step (S3 to S4) and a recommended value calculating step (S5 to S10).

The reducing agent flow model acquisition step (S1) is orthogonal to the share ratio parameter of each nozzle correlated with the ratio of the reducing agent injection amount from each of the plurality of nozzles 2 to the total injection amount of the reducing agent, and the exhaust gas flow direction. A reducing agent flow model showing a correlation with the concentration of the reducing agent on the inlet 4a side of the denitration reactor 4 in each of the plurality of sections k obtained by dividing the cross section of the denitration reactor 4 is obtained.
In the denitration reaction model acquisition step (S2), for each section of the denitration reactor 4, the concentration of the reducing agent on the inlet 4a side of the denitration reactor 4 and the concentration of the reducing agent on the outlet 4b side of the denitration reactor 4 are calculated. A denitration reaction model showing a correlation is obtained.

In the denitration reactor outlet side concentration calculation step (S3 to S4), the concentration of the reducing agent on the outlet side in each section is estimated from the candidate value of the sharing ratio parameter using the reducing agent flow model and the denitration reaction model.
Specifically, in the denitration reactor outlet side concentration calculation step (S3 to S4), the inlet of the denitration reactor 4 in the section k is calculated from the candidate value of the injection ratio of the reducing agent in the nozzle 2 using the reducing agent flow model. The reducing agent concentration B (k) on the 4a side is calculated (S3). Next, using the denitration reaction model, the reducing agent concentration X (k) on the outlet 4b side of the section k of the denitration reactor 4 is calculated from the reducing agent concentration B (k) on the inlet 4a side in the section k of the denitration reactor 4. (S4).

The recommended value calculation step (S5 to S10) calculates a recommended value of the sharing ratio parameter based on the estimated value of the concentration of the reducing agent.
In the step of calculating the recommended value of the sharing ratio parameter, the distribution of the estimated value of the concentration of the reducing agent on the outlet 4b side of the denitration reactor 4 in a plurality of sections, and the target of the reducing agent on the outlet 4b side of the denitration reactor 4 Based on the index indicating the deviation from the concentration distribution, a correction amount from the candidate value of the share ratio parameter to the recommended value is obtained using the reducing agent flow model and the denitration reaction model.
Specifically, the difference dX (k) of the reducing agent concentration X (k) on the outlet 4b side of the section k of the denitration reactor 4 with respect to the target concentration distribution on the outlet 4b side of the section k of the denitration reactor 4 is calculated. (S5). It is determined whether or not the deviation dX (k) is within the concentration management range (S6). If the deviation dX (k) is not within the concentration management range, the denitration reactor 4 is operated based on the deviation dX (k). A change amount dB (k) of the reducing agent concentration B (k) on the inlet 4a side in the section k is calculated (S7). Then, based on the change amount dB (k), a change amount of the share rate parameter of the nozzle 2 is calculated (S8), and the recommended value of the share rate parameter is determined from the share rate parameter candidate value and the change rate of the share rate parameter. Is determined (S9). If the deviation dX (k) is within the concentration management range, the sharing ratio parameter candidate value is directly adopted as the recommended value (S10).

  Thus, the reducing agent flow model and the denitration reaction model are also used in the step of calculating the recommended value of the sharing ratio parameter, and the distribution of the estimated concentration of the reducing agent on the outlet 4b side of the denitration reactor 4 and the target concentration distribution Based on an index indicating the deviation from the above, a correction amount from the candidate value of the sharing ratio parameter to the recommended value is obtained. Thereby, the reducing agent concentration on the outlet 4b side of the denitration reactor 4 can be made closer to the target concentration distribution.

In this case, the index indicating the deviation may be a deviation amount of the estimated value from the reducing agent concentration management range on the outlet 4b side of the denitration reactor 4.
According to this, it is possible to obtain a recommended value such that the concentration distribution of the reducing agent does not deviate from the concentration management range of the reducing agent, and it is possible to more appropriately control the injection amount sharing of the reducing agent.

In the above method, the sharing rate parameter may be a sharing rate indicating the ratio of the injection amount of each nozzle to the total injection amount of the reducing agent.
In this way, by using the sharing rate itself indicating the ratio of the injection amount of each nozzle to the total injection amount of the reducing agent as the sharing rate parameter, it is possible to reduce the calculation load when calculating the recommended value of the sharing rate parameter.

In one embodiment, the method further includes the step of calculating a recommended value of the opening of the valve for adjusting the injection amount of the reducing agent from the nozzle 2 from the recommended value of the sharing ratio of each nozzle as the sharing ratio parameter.
In this case, the share ratio parameter may be the opening of a valve for adjusting the amount of reducing agent injected from the nozzle.

  According to these structures, since the valve opening degree directly related to the adjustment of the reducing agent injection amount is used as the sharing rate parameter of the nozzle 2, the reducing agent injection amount is determined from the recommended value of the sharing rate. The procedure up to control can be simplified.

In the embodiment shown in FIG. 4, the reducing agent injection amount sharing control method includes a step of measuring the concentration of the reducing agent on the outlet 4b side of the denitration reactor 4 in each section k, and the denitration reactor in each section k. Correcting the denitration reaction model based on the deviation E (k) between the measured value X ₀ (k) and the estimated value X (k) of the concentration of the reducing agent on the outlet 4b side of 4 (S11 to S13); Prepare.
Specifically, as described above, after calculating the reducing agent concentration X (k) on the outlet 4b side of the section k of the denitration reactor 4 (S4), on the outlet 4b side of the denitration reactor 4 in each section k. A deviation E (k) between the measured value X ₀ (k) of the reducing agent concentration and the estimated value X (k) is calculated (S11). It is determined whether or not the deviation E (k) is within the allowable range (S12). If the deviation E (k) is within the allowable range, the deviation dX of X (k) with respect to the target density distribution as described above. Return to the calculation of (k) (S5). On the other hand, when the deviation E (k) is not within the allowable range, the denitration reaction model is corrected (S13), and the process returns to the calculation of the reducing agent concentration B (k) on the inlet 4a side of the section k of the denitration reactor 4 ( S3).

In the above method, the denitration reaction model is corrected based on the deviation E (k) between the estimated value X (k) of the concentration of the reducing agent on the outlet 4b side and the measured value X ₀ (k) in each section k. It has become. Thereby, it is possible to minimize the influence of the reduction in the denitration efficiency on the estimation of the reducing agent concentration, and to calculate the recommended value of the sharing rate parameter with high accuracy.

  Although illustration is omitted, the operation method of the denitration apparatus according to some embodiments adjusts the injection sharing rate of each nozzle based on the recommended value of the sharing rate parameter obtained by the reducing agent injection amount sharing control method described above. The step of carrying out is provided.

According to the above method, since the injection amount sharing of each nozzle 2 is adjusted based on the recommended value of the appropriate sharing rate parameter acquired by the above-described reducing agent injection amount sharing control method, the unreacted reducing agent Can be more effectively suppressed.
Therefore, it is possible to avoid a failure associated with the generation of acidic ammonium sulfate in the equipment provided on the downstream side of the denitration system 1, and it is possible to contribute to the continuous operation of the plant equipped with the denitration system 1.

As described above, according to at least one embodiment of the present invention, the diffusion state of the reducing agent in the exhaust gas between the nozzle 2 and the inlet 4a of the denitration reactor 4 and the denitration rate in the denitration reactor 4 are determined. In consideration, the concentration of the reducing agent on the outlet 4b side in each section k (see reference numerals 4-1, 4-2,..., 4-k in FIG. 2) is estimated for each candidate value of the sharing ratio parameter. be able to. Further, the recommended value of the sharing ratio parameter is calculated based on the estimated value of the concentration of the reducing agent. Thereby, it is possible to acquire a recommended value of an appropriate share ratio parameter that can avoid a local concentration increase of the unreacted reducing agent at the outlet 4b of the denitration reactor 4.
If the injection amount sharing of the nozzle 2 is controlled using the appropriate sharing rate parameter obtained in this way, the local increase of the unreacted reducing agent can be more effectively suppressed.
Further, it is possible to avoid the trouble caused by the generation of acidic ammonium sulfate in the equipment provided on the downstream side of the denitration system 1, and to contribute to the continuous operation of the plant equipped with the denitration system 1.

The present invention is not limited to the above-described embodiments, and includes forms obtained by modifying the above-described embodiments and forms obtained by appropriately combining these forms.
For example, expressions expressing relative or absolute arrangements such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric” or “coaxial” are strictly In addition to such an arrangement, it is also possible to represent a state of relative displacement with an angle or a distance such that tolerance or the same function can be obtained.
For example, an expression indicating that things such as “identical”, “equal”, and “homogeneous” are in an equal state not only represents an exactly equal state, but also has a tolerance or a difference that can provide the same function. It also represents the existing state.
For example, expressions representing shapes such as quadrangular shapes and cylindrical shapes represent not only geometrically strict shapes such as quadrangular shapes and cylindrical shapes, but also irregularities and chamfers as long as the same effects can be obtained. A shape including a part or the like is also expressed.
On the other hand, the expression “comprising”, “including”, or “having” one constituent element is not an exclusive expression that excludes the presence of the other constituent elements.

DESCRIPTION OF SYMBOLS 1 Denitration system 2 Nozzle 4 Denitration reactor 4a Inlet 4b Outlet 6 Reducing agent concentration detection part 8 Sharing ratio adjustment part 9 Model correction part 10 Boiler 12 Exhaust gas duct 16 Air preheater 18 NOx concentration detection part

Claims (15)

A plurality of injection parts for injecting a reducing agent into the exhaust gas; and a denitration reactor disposed downstream of the injection part, and the nitrogen is produced by a reaction between nitrogen oxides in the exhaust gas and the reducing agent. A method of adjusting the injection share of each injection portion in a denitration apparatus configured to decompose oxide,
A cross-section of the denitration reactor orthogonal to the exhaust gas flow direction, and a share ratio parameter of each injection part correlated with the ratio of the injection quantity of the reducing agent from each of the plurality of injection parts to the total injection quantity of the reducing agent Obtaining a reducing agent flow model showing a correlation with the concentration of the reducing agent on the inlet side of the denitration reactor in each of a plurality of sections obtained by dividing
Obtaining a denitration reaction model showing a correlation between the concentration of the reducing agent on the inlet side of the denitration reactor and the concentration of the reducing agent on the outlet side of the denitration reactor for each of the compartments;
Using the reducing agent flow model and the denitration reaction model to estimate the concentration of the reducing agent on the outlet side in each section from the candidate values of the sharing ratio parameter;
Calculating a recommended value of the sharing ratio parameter based on an estimated value of the concentration of the reducing agent;
A reducing agent injection amount sharing control method comprising:   In the step of calculating the recommended value of the sharing ratio parameter, the distribution of the estimated value of the reducing agent concentration on the outlet side of the denitration reactor in the plurality of compartments and the reducing agent on the outlet side of the denitration reactor A correction amount from the candidate value to the recommended value of the share ratio parameter is obtained using the reducing agent flow model and the denitration reaction model based on an index indicating a deviation from a target concentration distribution. The reducing agent injection amount sharing control method according to claim 1.   The reducing agent injection amount sharing control according to claim 2, wherein the index indicating the deviation is a deviation amount of the estimated value from a concentration management range of the reducing agent on the outlet side of the denitration reactor. Method. Measuring the concentration of the reducing agent on the outlet side of the denitration reactor in each compartment;
Correcting the denitration reaction model based on the deviation between the estimated value and the measured value of the concentration of the reducing agent on the outlet side in each compartment;
The reducing agent injection amount sharing control method according to any one of claims 1 to 3, further comprising:   The reducing agent injection amount sharing according to any one of claims 1 to 4, wherein the sharing rate parameter is a sharing rate indicating a ratio of an injection amount of each injection portion to a total injection amount of the reducing agent. Control method.   A step of calculating a recommended value of the opening of the valve for adjusting the injection amount of the reducing agent from the injection unit from the recommended value of the sharing rate of each injection unit as the sharing rate parameter; The reducing agent injection amount sharing control method according to claim 5, characterized in that:   5. The reducing agent injection amount according to claim 1, wherein the sharing ratio parameter is an opening degree of a valve for adjusting the injection amount of the reducing agent from the injection unit. Sharing control method. A plurality of injection parts for injecting a reducing agent into the exhaust gas; and a denitration reactor disposed downstream of the injection part, and the nitrogen is produced by a reaction between nitrogen oxides in the exhaust gas and the reducing agent. A method of operating a denitration apparatus configured to decompose oxide,
A step of adjusting the injection share ratio of each injection portion based on the recommended value of the share ratio parameter obtained by the reducing agent injection amount share control method according to any one of claims 1 to 7. A method for operating a denitration apparatus. A plurality of injection parts for injecting the reducing agent into the exhaust gas;
A denitration reactor disposed downstream of the injection portion and configured to decompose the nitrogen oxides by a reaction between the nitrogen oxides in the exhaust gas and the reducing agent;
For each of the injection units, a sharing rate adjustment unit for calculating a recommended value of a sharing rate parameter correlated with the ratio of the injection amount of the injection unit to the total injection amount of the reducing agent, and
The sharing ratio adjustment unit
Correlation between the sharing ratio parameter of each injection portion and the concentration of the reducing agent on the inlet side of the denitration reactor in each of a plurality of sections obtained by dividing a cross section of the denitration reactor orthogonal to the exhaust gas flow direction To obtain a reducing agent flow model
For each of the compartments, obtain a denitration reaction model showing a correlation between the concentration of the reducing agent on the inlet side of the denitration reactor and the concentration of the reducing agent on the outlet side of the denitration reactor;
Using the reducing agent flow model and the denitration reaction model, from the candidate values of the sharing ratio parameter, estimate the concentration of the reducing agent on the outlet side in each section,
A denitration system configured to calculate a recommended value of the sharing ratio parameter based on an estimated value of the concentration of the reducing agent.   The sharing ratio adjusting unit is configured to discriminate between the distribution of the estimated value of the concentration of the reducing agent on the outlet side of the denitration reactor in the plurality of sections and the target concentration distribution of the reducing agent on the outlet side of the denitration reactor. The correction amount from the candidate value to the recommended value of the share ratio parameter is obtained using the reducing agent flow model and the denitration reaction model based on an index indicating Item 10. The denitration system according to Item 9.   The denitration system according to claim 10, wherein the index indicating the deviation is a deviation amount of the estimated value from a concentration management range of the reducing agent on the outlet side of the denitration reactor.   The apparatus further comprises a model correction unit that corrects the denitration reaction model based on a deviation between the measured value of the concentration of the reducing agent on the outlet side of the denitration reactor in each section and the estimated value. The denitration system according to any one of 9 to 11.   The denitration system according to any one of claims 9 to 12, wherein the sharing ratio parameter is a sharing ratio indicating a ratio of an injection amount of each injection unit to a total injection amount of the reducing agent.   The share rate adjusting unit is configured to obtain a recommended value of a valve opening for adjusting the injection amount of the reducing agent from the injection unit from the recommended value of the share rate parameter of each injection unit as the share rate parameter. The denitration system according to any one of claims 9 to 13, wherein the denitration system is configured to calculate. The denitration system according to any one of claims 9 to 12, wherein the sharing ratio parameter is an opening degree of a valve for adjusting an injection amount of the reducing agent from the injection unit.

Images