CN107803114B

CN107803114B - Denitration control system and control method and control device thereof

Info

Publication number: CN107803114B
Application number: CN201711260199.1A
Authority: CN
Inventors: 任旻; 麦永强; 隋海涛; 吴真; 赵超; 吴德利; 高兴; 郝玉春; 董璐
Original assignee: Guodian Jiantou Inner Mongolia Energy Co Ltd Bulian Power Plant; Yantai Longyuan Power Technology Co Ltd
Current assignee: Guodian Jiantou Inner Mongolia Energy Co Ltd Bulian Power Plant; Yantai Longyuan Power Technology Co Ltd
Priority date: 2017-12-04
Filing date: 2017-12-04
Publication date: 2020-06-16
Anticipated expiration: 2037-12-04
Also published as: CN107803114A

Abstract

The invention discloses a denitration control system, a control method and a control device thereof. The control method comprises the following steps: acquiring the wind-coal ratio and the NOx concentration of an SCR inlet of a boiler in real time, and calculating the NOx concentration of the SCR inlet at a first moment and a first ratio of the wind-coal ratio acquired at a second moment before the first moment; determining a purging start time and a purging end time of the inlet purging operation, and determining a last first ratio calculated before the purging start time as an inlet target ratio of the inlet purging operation; when the inlet purging operation is performed, the product of the air-coal ratio at a third time before the current time and the inlet target ratio is used as the SCR inlet NOx substitute concentration. In the embodiment of the invention, the NOx substitute concentration at the SCR inlet is obtained when the SCR inlet is swept, so that the accurate measurement of the NOx at the SCR inlet is realized, and the stability and the safety of the SCR denitration system are improved.

Description

Denitration control system and control method and control device thereof

Technical Field

The embodiment of the invention relates to a flue gas pollution control technology, in particular to a denitration control system and a control method and a control device thereof.

Background

Nitrogen oxides (NOx) are one of the main atmospheric pollutants generated by coal-fired power plants, and among denitration techniques for removing NOx in flue gas discharged from coal-fired power plants, Selective Catalytic Reduction (SCR) denitration techniques and selective non-catalytic reduction (SCNR) denitration techniques are two mainstream denitration techniques currently applied. Compared with the SCNR denitration technology, the SCR denitration technology has the advantages of higher denitration efficiency, relatively simple device structure, easily controlled conditions and the like, and is a denitration technology widely adopted by domestic coal-fired power stations.

The principle of the SCR denitration technology is that NOx in flue gas is mixed with a reducing agent (ammonia gas, etc.), and then the NOx is reduced to pollution-free nitrogen gas under the action of a catalyst. The coal-fired boiler unit of the coal-fired power plant comprises a hearth, a flue, an economizer, an air preheater and other equipment, an SCR denitration system based on an SCR denitration technology is a denitration reaction device for a tail flue at the rear of a furnace, an SCR reactor is generally arranged between the outlet of the economizer at the rear of the furnace and the inlet of the air preheater, and the SCR reactor is used for accelerating the reaction of sprayed ammonia and NOx in flue gas under the action of a catalyst to complete the denitration process.

In the SCR denitration technology, the most important and core is the control of a reducing agent (ammonia gas and the like), the dosage of the reducing agent is accurately controlled, the aim of effective denitration can be achieved, and waste and additional pollution caused by excessive reducing agent can be prevented. When ammonia is used as a reducing agent, the existing SCR denitration technology mainly has two control modes: 1) a fixed mole ratio control mode (standard control mode), commonly used for feed forward control; 2) the outlet NOx fixed value control method is commonly used for feedback control. The basis of the two control modes is to accurately measure the concentration of NOx at the inlet and the outlet of the SCR reactor, and the SCR denitration system can obtain good denitration effect only on the basis of measuring the accurate concentration of the NOx. However, the flue gas sampling probes installed at the inlet and the outlet of the SCR reactor are easily blocked by dust, which affects the NOx concentration measurement effect, so that the purging controller is arranged at the position of the flue gas sampling probe to purge the flue gas sampling probe, which affects the accuracy of flue gas sampling during purging, resulting in inaccurate NOx concentration measurement.

In the prior art, the SCR denitration system fixes the last NOx concentration measurement measured before the start of purging, and adjusts the amount of reducing agent entering the SCR reactor as the NOx concentration during purging. As the concentration of NOx in the SCR denitration system can also change in real time during purging, the concentration of the reducing agent and the concentration of NOx can not be matched due to the fact that a certain NOx concentration value is fixed, and the stability and the safety of the SCR denitration system are affected.

Disclosure of Invention

The embodiment of the invention provides a denitration control system, a control method and a control device thereof, which are used for accurately measuring NOx at an inlet of an SCR reactor of an SCR denitration system and improving the stability and safety of the SCR denitration system.

In a first aspect, an embodiment of the present invention provides a control method of a denitration control system, where the denitration control system includes an SCR denitration system and a flue gas automatic monitoring system CEMS, the SCR denitration system includes an SCR reactor, and the CEMS includes a first purge controller disposed at an inlet of the SCR reactor and a second purge controller disposed at an outlet of the SCR reactor; the control method comprises the following steps:

acquiring the wind-coal ratio of a boiler and the concentration of nitrogen oxide NOx at an inlet of the SCR reactor in real time, and calculating the concentration of the NOx at the inlet of the SCR reactor acquired at a first moment and a first ratio of the wind-coal ratio acquired at a second moment before the first moment, wherein the time difference between the first moment and the second moment is first delay time;

determining an inlet purge start timing and an inlet purge end timing of an inlet purge operation performed by the first purge controller, determining last first ratio data calculated before the purge start timing as an inlet target ratio of the inlet purge operation;

and when the first purge controller is controlled to execute the inlet purge operation, taking the product of the wind-coal ratio at a third moment before the current moment and the inlet target ratio as the SCR reactor inlet NOx substitute concentration, wherein the difference between the current moment and the first delay time is the third moment.

Further, the determining of the first delay time includes:

determining a wind-coal ratio change curve segment according to the data of the wind-coal ratio from the time t1 to the time t2, and determining an SCR reactor inlet NOx concentration change curve segment according to the data of the SCR reactor inlet NOx concentration from the time t1 to the time t 2;

fitting the wind-coal ratio change curve segment and the SCR reactor inlet NOx concentration change curve segment to obtain a first wind-coal ratio change curve segment with consistent change trend and a first SCR reactor inlet NOx concentration change curve segment;

and determining the time interval between the starting time of the first curve segment of the wind-coal ratio and the starting time of the first curve segment of the SCR reactor inlet NOx concentration as the first delay time.

Further, the control method further includes:

when the first blowing controller is not controlled to execute the inlet blowing operation, adjusting the flow of ammonia entering the SCR reactor according to the concentration of NOx at the inlet of the SCR reactor obtained in real time; and when the first purging controller is controlled to execute the inlet purging operation, regulating the flow of the ammonia gas entering the SCR reactor according to the NOx substitute concentration at the inlet of the SCR reactor.

Further, the control method further includes:

acquiring the concentration of NOx at the inlet of the SCR reactor and the concentration of NOx at the outlet of the SCR reactor in real time, and calculating a second ratio of the concentration of NOx at the outlet of the SCR reactor, which is acquired at a fourth moment, to the concentration of NOx at the inlet of the SCR reactor, which is acquired at a fifth moment before the fourth moment, wherein the time difference between the fourth moment and the fifth moment is a second delay time;

determining an outlet purge start time and an outlet purge end time of an outlet purge operation performed by the second purge controller, determining last second ratio data calculated before the outlet purge start time as an outlet target ratio of the outlet purge operation;

and when the second purging controller is controlled to execute the outlet purging operation, taking the product of the SCR reactor inlet NOx concentration and the outlet target ratio at a sixth moment before the current moment as the SCR reactor outlet NOx substitute concentration, wherein the difference between the current moment and the second delay time is the sixth moment.

Further, the determining of the second delay time includes:

determining a SCR reactor inlet NOx concentration change curve segment according to the data of the SCR reactor inlet NOx concentration from the time t3 to the time t4, and determining an SCR reactor outlet NOx concentration change curve segment according to the data of the SCR reactor outlet NOx concentration from the time t3 to the time t 4;

fitting the SCR reactor inlet NOx concentration change curve segment and the SCR reactor outlet NOx concentration change curve segment to obtain an SCR reactor inlet NOx concentration second change curve segment and an SCR reactor outlet NOx concentration second change curve segment which have consistent change trends;

determining the second delay time as a time interval between the starting time of the second variation curve segment of the SCR reactor inlet NOx concentration and the starting time of the second variation curve segment of the SCR reactor outlet NOx concentration.

Further, the control method further includes:

and when the control is carried out simultaneously with the inlet purging operation and the outlet purging operation, taking the product of the SCR reactor inlet NOx alternative concentration and the outlet target ratio at the seventh moment before the current moment as the SCR reactor outlet NOx alternative concentration, wherein the difference between the current moment and the second delay time is the seventh moment.

Further, the control method further includes:

adjusting the flow of ammonia gas entering the SCR reactor according to the NOx substitute concentration at the inlet of the SCR reactor; and according to the NOx substitute concentration at the outlet of the SCR reactor, the flow of ammonia entering the SCR reactor is subjected to feedback regulation.

In a second aspect, an embodiment of the present invention further provides a control method of a denitration control system, where the denitration control system includes an SCR denitration system and a CEMS, the SCR denitration system includes an SCR reactor, and the CEMS includes a first purge controller disposed at an inlet of the SCR reactor and a second purge controller disposed at an outlet of the SCR reactor; the control method comprises the following steps:

Further, the determining of the second delay time includes:

Further, the control method further includes:

adjusting the flow of ammonia entering the SCR reactor according to the concentration of NOx at the inlet of the SCR reactor obtained in real time; and according to the NOx substitute concentration at the outlet of the SCR reactor, the flow of ammonia entering the SCR reactor is subjected to feedback regulation.

In a third aspect, an embodiment of the present invention provides a control device for a denitration control system, where the control device includes:

the calculation ratio module is used for acquiring the wind-coal ratio of the boiler and the NOx concentration at the inlet of the SCR reactor in real time, and calculating a first ratio of the NOx concentration at the inlet of the SCR reactor acquired at a first moment and the wind-coal ratio acquired at a second moment before the first moment, wherein the time difference between the first moment and the second moment is first delay time;

the system comprises an identification purging module, a comparison module and a comparison module, wherein the identification purging module is used for determining an inlet purging starting moment and an inlet purging ending moment of an inlet purging operation, and determining the last first ratio data calculated before the purging starting moment as an inlet target ratio of the inlet purging operation;

and the measuring point replacing module is used for taking the product of the wind-coal ratio at a third moment before the current moment and the inlet target ratio as the NOx replacing concentration at the inlet of the SCR reactor when the inlet purging operation is executed, and the difference value between the current moment and the first delay time is the third moment.

In a fourth aspect, an embodiment of the present invention further provides a control apparatus for a denitration control system, where the apparatus includes:

the calculation ratio module is used for acquiring the concentration of NOx at the inlet of the SCR reactor and the concentration of NOx at the outlet of the SCR reactor in real time, calculating a second ratio of the concentration of NOx at the outlet of the SCR reactor acquired at a fourth moment and the concentration of NOx at the inlet of the SCR reactor acquired at a fifth moment before the fourth moment, and setting a time difference between the fourth moment and the fifth moment as a second delay time;

the identification purging module is used for determining an outlet purging starting time and an outlet purging ending time of the outlet purging operation, and determining the last second ratio data calculated before the outlet purging starting time as an outlet target ratio of a second purging operation;

and the measuring point replacing module is used for taking the product of the SCR reactor inlet NOx concentration and the outlet target ratio at the sixth moment before the current moment as the SCR reactor outlet NOx replacing concentration when the outlet purging operation is executed, and the difference value between the current moment and the second delay time is the sixth moment.

In a fifth aspect, embodiments of the present invention further provide a denitration control system, which includes an SCR denitration system and a CEMS, where the SCR denitration system includes an SCR reactor, and the CEMS includes a first purge controller disposed at an inlet of the SCR reactor, a second purge controller disposed at an outlet of the SCR reactor, and the control device as described above.

The embodiment of the invention provides a control method and a control device of a denitration control system, wherein the method comprises the steps of obtaining the wind coal ratio of a boiler and the NOx concentration of an inlet of an SCR (selective catalytic reduction) reactor in real time, calculating the NOx concentration of the inlet of the SCR reactor obtained at a first moment and a first ratio of the wind coal ratio obtained at a second moment before the first moment, and setting a time difference value between the first moment and the second moment as a first delay time; determining an inlet purging start time and an inlet purging end time of the inlet purging operation, and determining last first ratio data calculated before the purging start time as an inlet target ratio of the inlet purging operation; and during the inlet purging operation, taking the product of the air-coal ratio and the inlet target ratio at a third moment before the current moment as the SCR reactor inlet NOx alternative concentration, wherein the difference between the current moment and the first delay time is the third moment. Through the technical scheme, the NOx alternative concentration at the inlet of the SCR reactor during purging is obtained according to the relation between the wind-coal ratio and the NOx concentration at the inlet of the SCR reactor, the problem that the NOx concentration at the inlet of the SCR reactor cannot be accurately measured during purging is solved, and the stability and the safety of an SCR denitration system are improved.

Drawings

FIG. 1 is a schematic diagram of a prior art SCR-based denitration control system;

fig. 2 is a schematic flow chart illustrating a control method of a denitration control system according to an embodiment of the present invention;

FIG. 3 is a diagram illustrating a first delay time determination process according to a first embodiment of the present invention;

FIG. 4 is a schematic flow chart of controlling the purging of the outlet of the SCR reactor according to the second embodiment of the present invention;

fig. 5 is a diagram illustrating a second delay time determination process in the second embodiment of the present invention;

fig. 6 is a schematic flowchart of a control method of a denitration control system according to a third embodiment of the present invention;

fig. 7 is a schematic structural diagram of a control device of a denitration control system according to a fourth embodiment of the present invention;

fig. 8 is a schematic structural diagram of a control device of a denitration control system according to a fifth embodiment of the present invention;

fig. 9 is a schematic structural diagram of a denitration control system according to a sixth embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Before discussing exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although a flowchart may describe the operations (or steps) as a sequential process, many of the operations can be performed in parallel, concurrently or simultaneously. In addition, the order of the operations may be re-arranged. The process may be terminated when its operations are completed, but may have additional steps not included in the figure. The processes may correspond to methods, functions, procedures, subroutines, and the like.

Fig. 1 is a schematic structural diagram of a denitration control system based on SCR, which mainly includes a furnace 1, an economizer 2, an ammonia injection device 3, an SCR reactor 4, an air preheater 5 and a CEMS6, and some other structures are omitted for simplicity. The hearth 1, the economizer 2, the SCR reactor 4 and the air preheater 5 are connected by a flue. The CEMS6 mainly comprises a flue gas sampling probe 61, a transmission cable 62 and an analysis processing device 63, wherein the transmission cable 62 is connected with the flue gas sampling probe 61 and the analysis processing device 63 and is used for transmitting flue gas data acquired by the flue gas sampling probe 61 to the analysis processing device 63 for analysis processing so as to obtain information such as NOx concentration in the flue gas.

Because the SCR reactor 4 of the SCR denitration system is generally arranged on the flue between the economizer 2 at the tail part of the hearth 1 and the air preheater 5, the flue gas in the section of flue does not pass through a dust removal device, the dust concentration content in the flue gas is extremely high, and the flue gas sampling probes 61 of the CEMS6 are arranged at the inlet and the outlet of the SCR reactor 4, so that the flue gas sampling probes 61 are easily blocked by the dust. In order to prevent dust from blocking the flue gas sampling probe 61 and affecting the measurement effect of the NOx concentration, a purging controller (not shown in the figure) is often arranged at the position of the flue gas sampling probe 61 to purge the flue gas sampling probe 61, and during purging, the accuracy of flue gas sampling is affected, so that the measurement of the NOx concentration is inaccurate.

In the prior art, the SCR denitration system fixes the last NOx concentration measurement measured before the start of purging, and adjusts the amount of reducing agent entering the SCR reactor 4 as the NOx concentration during purging. As the concentration of NOx in the SCR denitration system can also change in real time during purging, the concentration of the reducing agent and the concentration of NOx can not be matched due to the fact that a certain NOx concentration value is fixed, and the stability and the safety of the SCR denitration system are affected.

Example one

Fig. 2 is a schematic flow chart of a control method of a denitration control system according to an embodiment of the present invention, where the embodiment is applicable to a situation where the first purge controller of the CEMS purges an inlet of the SCR reactor, and the method may be implemented by a control device of the denitration control system, where the control device is implemented by software and/or hardware, and the control device is configured in the denitration control system.

The control method of the denitration control system provided in this embodiment, where the denitration control system includes an SCR denitration system and a CEMS, the SCR denitration system includes an SCR reactor, the CEMS includes a first purge controller disposed at an inlet of the SCR reactor and a second purge controller disposed at an outlet of the SCR reactor, and the control method specifically includes the following steps:

and 110, acquiring the wind-coal ratio of the boiler and the NOx concentration at the inlet of the SCR reactor in real time, and calculating a first ratio of the NOx concentration at the inlet of the SCR reactor acquired at a first moment and the wind-coal ratio acquired at a second moment before the first moment, wherein the time difference between the first moment and the second moment is first delay time.

In this embodiment, the air-coal ratio of the boiler is a ratio of a total air volume entering the boiler to a total coal consumption, and can be obtained in real time by a Distributed Control System (DCS) integrated in the SCR denitration system. The SCR reactor inlet NOx concentration may be measured by CEMS. Illustratively, a flue gas sampling probe arranged at an inlet of the SCR reactor collects flue gas at the inlet of the SCR reactor in real time, and the flue gas is transmitted to a control device through a transmission line cable for analysis and treatment, so that the concentration of NOx at the inlet of the SCR reactor is obtained. It should be noted that, flue gas sampling probes can be arranged at a plurality of positions at the inlet of the SCR reactor, and a plurality of flue gas sampling probes can simultaneously sample a plurality of positions in real time, and the NOx concentration is obtained by the control device.

NOx is generated by the combustion of coal and the coal combustion and flue gas flow take some time, and changes in the air-to-coal ratio of the boiler can cause changes in the NOx concentration in the boiler flue gas. Through the historical data analysis of the air-coal ratio of the boiler and the NOx concentration at the inlet of the SCR reactor, the change trend of the NOx concentration at the inlet of the SCR reactor follows the change of the air-coal ratio trend and has a first delay time. For example, 9: 30 coal entering the boiler is combusted after five minutes, the tail gas contains NOx, the NOx reaches the inlet of the SCR reactor after one minute, 9: 36 sampling the SCR reactor inlet NOx by means of a flue gas sampling probe, then 9: first time 36, 9: the SCR reactor inlet NOx concentration at 36 is approximately 9: a wind-coal ratio of 30 is directly related, so 9: second time 30, 9: 36 and 9: the time difference of 30 is the first delay time (i.e., 6 minutes) and there is a first ratio of the SCR reactor inlet NOx concentration at the first time to the air-to-coal ratio at the second time.

In practice, the wind-coal ratio and the concentration of NOx at the inlet of the SCR reactor are changed in real time, the change trend of the concentration of NOx at the inlet of the SCR reactor at the first moment is the same as that of the concentration of NOx at the inlet of the SCR reactor at the second moment, the time difference value between the first moment and the second moment is first delay time, and the ratio of the concentration of NOx at the inlet of the SCR reactor at the first moment to the concentration of NOx at the inlet of the SCR reactor at the second moment is defined as a first ratio. Therefore, the first ratio is calculated in real time by taking the current time as the first time and the time before the first delay time of the current time as the second time, and the first ratio is changed in real time.

And step 120, determining an inlet purging start time and an inlet purging end time of the inlet purging operation executed by the first purging controller, and determining the last first ratio data calculated before the purging start time as an inlet target ratio of the inlet purging operation.

The first blowing controller is arranged at an inlet of the SCR reactor and used for blowing the flue gas sampling probe. It should be noted that the air outlet that the first sweeping controller is used for sweeping corresponds to the flue gas sampling probe one to one, and when a plurality of flue gas sampling probes exist, the first sweeping controller can sweep only one certain flue gas sampling probe, and can sweep a plurality of flue gas sampling probes simultaneously. The purge may be continued for a period of time, for example, by controlling the first purge controller to switch between 10: 00 to 10: purging is performed for a period of 10, and the purging lasts ten minutes, then 10: 00 and 10 to end purge: 10 are respectively the inlet purging start time and the inlet purging end time, and within ten minutes of the purging time, 10: 00 the last first ratio calculated according to step 110 the last time before is used as the inlet target ratio for this inlet purge operation.

And step 130, when the first purging controller is controlled to perform the inlet purging operation, taking the product of the wind-coal ratio and the inlet target ratio at a third moment before the current moment as the SCR reactor inlet NOx substitute concentration, wherein the difference value between the current moment and the first delay time is the third moment.

Continuing with the example based on the two steps, if the current time is 10: 05, the first delay time is 6 minutes, the third time is 9: 59, at which time the SCR reactor inlet NOx replacement concentration is equal to the inlet target ratio x 9: 59 air-coal ratio.

According to the control method of the denitration control system provided by the embodiment of the invention, the NOx alternative concentration of the SCR reactor inlet in the period of being swept is obtained according to the relation between the wind-coal ratio and the NOx concentration of the SCR reactor inlet, the problem that the NOx concentration of the SCR reactor inlet cannot be accurately measured in the period of being swept is solved, and the stability and the safety of the SCR denitration system are improved.

Further, the first delay time may be determined by the following process:

determining a wind-coal ratio change curve segment according to the data of the wind-coal ratio from the time t1 to the time t2, and determining an SCR reactor inlet NOx concentration change curve segment according to the data of the SCR reactor inlet NOx concentration from the time t1 to the time t 2; fitting the wind-coal ratio change curve segment and the SCR reactor inlet NOx concentration change curve segment to obtain a first wind-coal ratio change curve segment with consistent change trend and a first SCR reactor inlet NOx concentration change curve segment; and determining the time interval between the starting time of the first curve segment of the wind coal ratio and the starting time of the first curve segment of the NOx concentration at the inlet of the SCR reactor as a first delay time.

As described above, fig. 3 is taken as an example for explanation, and fig. 3 is a schematic diagram of the first delay time determination process. Wherein, the curve 11 represents a wind-coal ratio change curve segment obtained by fitting data of the wind-coal ratio in a time period from t1 to t2 according to the wind-coal ratio in the time period; curve 12 represents the section of the SCR reactor inlet NOx concentration change curve obtained by fitting the data of the SCR reactor inlet NOx concentration in the time period from t1 to t 2; curve 13 represents a first variation curve segment of the wind-coal ratio, and a represents the starting time of the first variation curve segment of the wind-coal ratio; curve 14 represents a first curve segment of the SCR reactor inlet NOx concentration, and b represents the starting point of the first curve segment of the SCR reactor inlet NOx concentration, wherein the first curve segment of the wind/coal ratio and the first curve segment of the SCR reactor inlet NOx concentration have the same trend. The time interval between a and b is the first delay time T1.

Further, the control method further includes: when the first blowing controller is not controlled to execute inlet blowing operation, adjusting the flow of ammonia entering the SCR reactor according to the concentration of NOx at the inlet of the SCR reactor obtained in real time; and when the first purging controller is controlled to execute the inlet purging operation, the flow of the ammonia gas entering the SCR reactor is adjusted according to the NOx substitute concentration at the inlet of the SCR reactor.

For example, setting 10: 00-10: purge time, 10, at 10: 00-10: during the purge period of 10, the SCR reactor inlet NOx surrogate concentration is obtained using the method of the previous example, and the flow of ammonia into the SCR reactor is adjusted according to this surrogate concentration. It will be understood by those skilled in the art that the adjustment of the flow rate of ammonia gas entering the SCR reactor can be performed by a method conventionally used for controlling the flow rate of ammonia gas in an SCR denitration system, and ammonia gas can be obtained by liquid ammonia, urea hydrolysis, urea pyrolysis and the like, and will not be described in detail herein. In a step other than 10: 00-10: and (5) adjusting the flow of ammonia entering the SCR reactor in a non-purging time period other than 10 according to the concentration of NOx at the inlet of the SCR reactor, which is obtained by real-time sampling of the flue gas sampling probe and analysis of the control device.

Example two

On the basis of the foregoing embodiment, the control method provided in this embodiment may further purge a flue gas sampling probe at an outlet of the SCR reactor, and as shown in fig. 4 correspondingly, the control method provided in this embodiment further includes the following steps:

and step 140, acquiring the concentration of the NOx at the inlet of the SCR reactor and the concentration of the NOx at the outlet of the SCR reactor in real time, and calculating a second ratio of the concentration of the NOx at the outlet of the SCR reactor acquired at the fourth moment and the concentration of the NOx at the inlet of the SCR reactor acquired at the fifth moment before the fourth moment, wherein the time difference between the fourth moment and the fifth moment is a second delay time.

Wherein the SCR reactor inlet NOx concentration and the SCR reactor outlet NOx concentration may be measured by CEMS. Illustratively, flue gas sampling probes respectively arranged at the inlet and the outlet of the SCR reactor collect flue gas at the inlet and the outlet of the SCR reactor in real time, and the flue gas is transmitted to a control device through a transmission line cable to be analyzed and processed respectively, so that NOx concentrations at the inlet and the outlet of the SCR reactor are obtained.

It should be noted that the inlet and the outlet of the SCR reactor may be provided with a plurality of flue gas sampling probes at a plurality of positions, and the plurality of flue gas sampling probes may sample a plurality of positions at the same time in real time, and the NOx concentration may be obtained by the control device.

The reaction of NOx with ammonia over a catalyst in the SCR reactor requires a certain amount of time, and the flow of unreacted NOx from the inlet to the outlet of the SCR reactor also requires a certain amount of time. Through the historical data analysis of the SCR reactor inlet NOx concentration and the SCR reactor outlet NOx concentration, the SCR reactor outlet NOx concentration variation trend follows the SCR reactor inlet NOx concentration trend and a second delay time exists. For example, 10: 30, the NOx entering the SCR reactor undergoes a four minute catalytic reduction reaction, after one minute unreacted NOx reaches the SCR reactor outlet, 10: 35 sampling the outlet NOx of the SCR reactor by means of a flue gas sampling probe, then 10: fourth time 35, 10: SCR reactor outlet NOx concentration at 35 is in the range of 10: 30 SCR reactor inlet NOx concentration is directly related, 10: fifth timing 30, 10: 35 and 10: the time difference of 30 is the second delay time (i.e., 5 minutes) and there is a second ratio of the SCR reactor outlet NOx concentration at the fourth time to the SCR reactor inlet NOx concentration at the fifth time.

In practice, the concentration of the NOx at the inlet of the SCR reactor and the concentration of the NOx at the outlet of the SCR reactor are both changed in real time, the change trend of the concentration of the NOx at the outlet of the SCR reactor at the fourth time is the same as that of the concentration of the NOx at the inlet of the SCR reactor at the fifth time, the time difference between the fourth time and the fifth time is a second delay time, and the ratio of the concentration of the NOx at the outlet of the SCR reactor at the fourth time to the wind-coal ratio at the fifth time is defined as a second ratio. Therefore, the current time is taken as the fourth time, the time before the second delay time of the current time is taken as the fifth time, the second ratio is calculated in real time, and the second ratio changes in real time.

And 150, determining an outlet purging starting time and an outlet purging ending time of the outlet purging operation executed by the second purging controller, and determining the last second ratio data calculated before the outlet purging starting time as an outlet target ratio of the outlet purging operation.

And the second purging controller is arranged at the outlet of the SCR reactor and is used for purging the flue gas sampling probe. It should be noted that the air outlet that the second sweeps the controller and is used for sweeping corresponds with flue gas sampling probe one-to-one, and when there are a plurality of flue gas sampling probes, the second sweeps the controller and can sweep a certain flue gas sampling probe only, also can sweep a plurality of simultaneously. The purge may be continued for a period of time, for example, by controlling the second purge controller to switch between 11: 00 to 11: purging is performed for a period of 10 minutes, and for ten minutes, then 11: 00 and 11 to end purge: 10 are respectively the initial moment and the end moment of the outlet purging, and in the purging time of ten minutes, 11 is taken: 00 the last second ratio calculated according to step 140 for the last time before is taken as the outlet target ratio during the outlet purge.

And step 160, when the second purging controller is controlled to execute the outlet purging operation, taking the product of the inlet NOx concentration of the SCR reactor at the sixth moment before the current moment and the outlet target ratio as the outlet NOx substitute concentration of the SCR reactor, wherein the difference value between the current moment and the second delay time is the sixth moment.

Continuing with the example based on the two steps, if the current time is 11: 05, the second delay time is 5 minutes, the sixth time is 11: 00, when the NOx substitution concentration at the outlet of the SCR reactor is equal to the outlet target ratio × 11: 00SCR reactor inlet NOx concentration.

According to the control method of the denitration control system provided by the embodiment of the invention, the NOx alternative concentration of the SCR reactor outlet in the period of being swept is obtained according to the relation between the concentration of the NOx at the inlet of the SCR reactor and the concentration of the NOx at the outlet of the SCR reactor, the problem that the concentration of the NOx at the outlet of the SCR reactor cannot be accurately measured in the period of being swept is solved, and the stability and the safety of the SCR denitration system are improved.

Further, the second delay time may be determined by the following process:

determining a NOx concentration change curve segment at the inlet of the SCR reactor according to the data of the NOx concentration at the inlet of the SCR reactor from the time t3 to the time t4, and determining a NOx concentration change curve segment at the outlet of the SCR reactor according to the data of the NOx concentration at the outlet of the SCR reactor from the time t3 to the time t 4; fitting the SCR reactor inlet NOx concentration change curve segment and the SCR reactor outlet NOx concentration change curve segment to obtain an SCR reactor inlet NOx concentration second change curve segment and an SCR reactor outlet NOx concentration second change curve segment which have consistent change trends; the time interval between the start of the second curve segment of the SCR reactor inlet NOx concentration and the start of the second curve segment of the SCR reactor outlet NOx concentration is determined as a second delay time.

Illustratively, fig. 5 is a schematic diagram of the second delay time determination process. Wherein, the curve 21 represents a curve segment of the NOx concentration change of the inlet of the SCR reactor, which is obtained by fitting the data of the NOx concentration of the inlet of the SCR reactor in the time segment from t3 to t 4; the curve 22 represents a curve segment of the change of the NOx concentration at the outlet of the SCR reactor, which is obtained by fitting the data of the NOx concentration at the outlet of the SCR reactor in the time segment from t3 to t 4; curve 23 represents a second curve segment of the SCR reactor inlet NOx concentration, c represents the starting moment of the second curve segment of the SCR reactor inlet NOx concentration; curve 24 represents a second curve segment of the SCR reactor outlet NOx concentration, wherein the second curve segment of the SCR reactor inlet NOx concentration and the second curve segment of the SCR reactor outlet NOx concentration have the same trend. The time interval between c and d is T2 as the second delay time.

Further, the control method further includes: and when the inlet purging operation and the outlet purging operation are executed simultaneously, taking the product of the SCR reactor inlet NOx alternative concentration and the outlet target ratio at the seventh moment before the current moment as the SCR reactor outlet NOx alternative concentration, wherein the difference value between the current moment and the second delay time is the seventh moment.

Based on the foregoing example, for example, 10: 00-10: and (3) simultaneously purging the inlet and the outlet of the SCR reactor at 10 hours, and if the current time is 10: 05, then the seventh moment is 10: 00, since here the SCR reactor inlet is also purged, 10: at time 00, the NOx replacement concentration at the inlet of the SCR reactor is equal to the inlet target ratio × 9: 54 air-coal ratio. Therefore, at this time, the SCR reactor outlet NOx substitution concentration is equal to the outlet target ratio × 10: 00SCR reactor inlet NOx substitution concentration.

Further, the control method further includes: adjusting the flow of ammonia entering the SCR reactor according to the NOx substitution concentration at the inlet of the SCR reactor; and according to the NOx substitution concentration at the outlet of the SCR reactor, the flow of the ammonia gas entering the SCR reactor is subjected to feedback regulation.

According to the foregoing example, when the SCR reactor inlet and outlet are purged simultaneously, the flow of ammonia into the SCR reactor is adjusted using the SCR reactor inlet NOx surrogate concentration, while the flow of ammonia into the SCR reactor is feedback adjusted according to the SCR reactor outlet NOx surrogate concentration. Can further reduce the concentration of NOx in the flue gas, and has better denitration effect. It will be understood by those skilled in the art that the adjustment of the flow rate of ammonia gas entering the SCR reactor can be performed by a method conventionally used for controlling the flow rate of ammonia gas in an SCR denitration system, and ammonia gas can be obtained by liquid ammonia, urea hydrolysis, urea pyrolysis and the like, and will not be described in detail herein.

According to the control method of the denitration control system provided by the embodiment of the invention, the NOx alternative concentration during the period that the inlet of the SCR reactor is purged is obtained according to the relation between the wind-coal ratio and the NOx concentration at the inlet of the SCR reactor, the NOx alternative concentration during the period that the outlet of the SCR reactor is purged is obtained according to the relation between the NOx concentration at the inlet of the SCR reactor and the NOx concentration at the outlet of the SCR reactor, the problem that the NOx concentrations at the inlet and the outlet of the SCR reactor cannot be accurately measured during purging is solved, and the stability and the safety of the SCR denitration system are improved.

EXAMPLE III

Fig. 6 is a schematic flow chart of a control method of a denitration control system according to a third embodiment of the present invention, where in the case that the second purge controller applicable to the CEMS purges the outlet of the SCR reactor, the method may be implemented by a control device of the SCR denitration system, the control device is implemented by software and/or hardware, and the control device is configured in the denitration control system.

and step 210, acquiring the concentration of NOx at the inlet of the SCR reactor and the concentration of NOx at the outlet of the SCR reactor in real time, and calculating a second ratio of the concentration of NOx at the outlet of the SCR reactor, which is acquired at the fourth moment, to the concentration of NOx at the inlet of the SCR reactor, which is acquired at the fifth moment before the fourth moment, wherein the time difference between the fourth moment and the fifth moment is a second delay time.

In this embodiment, the SCR reactor inlet NOx concentration and the SCR reactor outlet NOx concentration may be measured by CEMS. Illustratively, flue gas sampling probes respectively arranged at the inlet and the outlet of the SCR reactor collect flue gas at the inlet and the outlet of the SCR reactor in real time, and the flue gas is transmitted to a control device through a transmission line cable to be analyzed and processed respectively, so that NOx concentrations at the inlet and the outlet of the SCR reactor are obtained.

It should be noted that the inlet and the outlet of the SCR reactor may be provided with a plurality of flue gas sampling probes at a plurality of positions, and the plurality of flue gas sampling probes may sample a plurality of positions at the same time in real time, and the NOx concentration may be obtained by the control device. The reaction of NOx with ammonia over a catalyst in the SCR reactor requires a certain amount of time, and the flow of unreacted NOx from the inlet to the outlet of the SCR reactor also requires a certain amount of time. Through the historical data analysis of the SCR reactor inlet NOx concentration and the SCR reactor outlet NOx concentration, the SCR reactor outlet NOx concentration variation trend follows the SCR reactor inlet NOx concentration trend and a second delay time exists. For example, 10: 30, the NOx entering the SCR reactor undergoes a four minute catalytic reduction reaction, after one minute unreacted NOx reaches the SCR reactor outlet, 10: 35 sampling the outlet NOx of the SCR reactor by means of a flue gas sampling probe, then 10: fourth time 35, 10: SCR reactor outlet NOx concentration at 35 is in the range of 10: 30 SCR reactor inlet NOx concentration is directly related, 10: fifth timing 30, 10: 35 and 10: the time difference of 30 is the second delay time (i.e., 5 minutes) and there is a second ratio of the SCR outlet NOx concentration at the fourth time to the SCR inlet NOx concentration at the fifth time.

And step 220, determining an outlet purging starting time and an outlet purging ending time of the outlet purging operation executed by the second purging controller, and determining the last second ratio data calculated before the outlet purging starting time as an outlet target ratio of the outlet purging operation.

And the second purging controller is arranged at the outlet of the SCR reactor and is used for purging the flue gas sampling probe. It should be noted that the air outlet that the second sweeps the controller and is used for sweeping corresponds with flue gas sampling probe one-to-one, and when there are a plurality of flue gas sampling probes, the second sweeps the controller and can sweep a certain flue gas sampling probe only, also can sweep a plurality of simultaneously. The purge may be continued for a period of time, for example, by controlling the second purge controller to switch between 11: 00 to 11: purging is performed for a period of 10 minutes, and for ten minutes, then 11: 00 and 11 to end purge: 10 are respectively the inlet purging start time and the inlet purging end time, and in the purging time of ten minutes, 11 is taken: 00 the last second ratio calculated according to step 210 for the last time is taken as the outlet target ratio during the outlet purge.

And step 230, when the second purging controller is controlled to execute the outlet purging operation, taking the product of the SCR reactor inlet NOx concentration and the outlet target ratio at a sixth moment before the current moment as the SCR reactor outlet NOx substitute concentration, wherein the difference value between the current moment and the second delay time is the sixth moment.

Further, the process of determining the second delay time is the same as that in the second embodiment, and will not be described in detail here.

Further, the control method further includes: adjusting the flow of ammonia entering the SCR reactor according to the concentration of NOx at the inlet of the SCR reactor obtained in real time; and according to the NOx substitution concentration at the outlet of the SCR reactor, the flow of the ammonia gas entering the SCR reactor is subjected to feedback regulation.

By way of example, the purge at the second purge controller to the SCR reactor outlet 11: 00-11: and during 10, regulating the flow of ammonia entering the SCR reactor by utilizing the NOx concentration at the outlet of the SCR reactor obtained in real time, and simultaneously obtaining the NOx substitute concentration at the outlet of the SCR reactor according to the method in the previous example and carrying out feedback regulation on the flow of ammonia entering the SCR reactor. Can further reduce the concentration of NOx in the flue gas, and has better denitration effect. It will be understood by those skilled in the art that the adjustment of the flow rate of ammonia gas entering the SCR reactor can be performed by a method conventionally used for controlling the flow rate of ammonia gas in an SCR denitration system, and ammonia gas can be obtained by liquid ammonia, urea hydrolysis, urea pyrolysis and the like, and will not be described in detail herein.

Example four

Fig. 7 is a schematic structural diagram of a control device of a denitration control system according to a fourth embodiment of the present invention, which is applicable to a situation where an inlet of an SCR reactor is purged, and is used to execute the control methods according to embodiments 1 to 2. The control device specifically comprises a ratio calculating module 310, an identification purging module 320, and a point replacing module 330.

The calculation ratio module 310 is configured to obtain an air-coal ratio of the boiler and an NOx concentration at an inlet of the SCR reactor in real time, and calculate a first ratio between the NOx concentration at the inlet of the SCR reactor obtained at a first time and the air-coal ratio obtained at a second time before the first time, where a time difference between the first time and the second time is a first delay time.

The identify purge module 320 is configured to determine an inlet purge start time and an inlet purge end time of the inlet purge operation, and determine the last first ratio data calculated before the purge start time as an inlet target ratio of the inlet purge operation.

And the measurement point replacing module 330 is configured to, when performing an inlet purging operation, take a product of a wind-coal ratio at a third time before the current time and an inlet target ratio as an SCR reactor inlet NOx replacement concentration, where a difference between the current time and the first delay time is the third time.

It can be understood that the control device can also be provided with a control chip for controlling the SCR denitration system and the CEMS; or two control chips can be arranged to respectively and independently control the SCR denitration system and the CEMS so as to enable the SCR denitration system and the CEMS to work in a matched manner.

Further, the determining process of the first delay time includes:

Further, the control device is further configured to: when the inlet purging operation is not executed, adjusting the flow of ammonia entering the SCR reactor according to the real-time acquired NOx concentration at the inlet of the SCR reactor; and when the inlet purging operation is executed, adjusting the flow of ammonia entering the SCR reactor according to the NOx substitute concentration at the inlet of the SCR reactor.

Further, the control device is further configured to: acquiring the concentration of NOx at the inlet of the SCR reactor and the concentration of NOx at the outlet of the SCR reactor in real time, and calculating a second ratio of the concentration of NOx at the outlet of the SCR reactor, which is acquired at a fourth moment, to the concentration of NOx at the inlet of the SCR reactor, which is acquired at a fifth moment before the fourth moment, wherein the time difference between the fourth moment and the fifth moment is a second delay time;

determining an outlet purge start time and an outlet purge end time of the outlet purge operation performed by the second purge controller, and determining the last second ratio data calculated before the outlet purge start time as an outlet target ratio of the outlet purge operation;

and when the second purging controller is controlled to execute the outlet purging operation, taking the product of the SCR reactor inlet NOx concentration and the outlet target ratio at the sixth moment before the current moment as the SCR reactor outlet NOx substitute concentration, wherein the difference between the current moment and the second delay time is the sixth moment.

Further, the determining process of the second delay time includes:

Further, the control device is further configured to: and when the control is carried out simultaneously with the inlet purging operation and the outlet purging operation, taking the product of the SCR reactor inlet NOx alternative concentration and the outlet target ratio at the seventh moment before the current moment as the SCR reactor outlet NOx alternative concentration, wherein the difference value between the current moment and the second delay time is the seventh moment.

Further, the control device is further configured to: adjusting the flow of ammonia entering the SCR reactor according to the NOx substitution concentration at the inlet of the SCR reactor; and according to the NOx substitution concentration at the outlet of the SCR reactor, the flow of the ammonia gas entering the SCR reactor is subjected to feedback regulation.

According to the technical scheme of the embodiment, the NOx alternative concentration of the inlet of the SCR reactor during the period that the inlet of the SCR reactor is blown is obtained according to the relation between the wind-coal ratio and the NOx concentration of the inlet of the SCR reactor, the problem that the NOx concentration of the inlet of the SCR reactor cannot be accurately measured during the period that the inlet of the SCR reactor is blown is solved, the NOx alternative concentration of the outlet of the SCR reactor during the period that the outlet of the SCR reactor is blown is obtained according to the relation between the NOx concentration of the inlet of the SCR reactor and the NOx concentration of the outlet of the SCR reactor, the problem that the NOx concentration of the outlet of the SCR reactor cannot be accurately measured during the period that.

EXAMPLE five

Fig. 8 is a schematic structural diagram of a control device of a denitration control system according to a fifth embodiment of the present invention, which is applicable to a situation where an outlet of an SCR reactor is purged, and is configured to execute the control method according to the foregoing embodiment 3. The control device specifically comprises a ratio calculating module 410, an identification purging module 420 and a measuring point replacing module 430.

The ratio calculating module 410 is configured to obtain the NOx concentration at the inlet of the SCR reactor and the NOx concentration at the outlet of the SCR reactor in real time, and calculate a second ratio between the NOx concentration at the outlet of the SCR reactor obtained at the fourth time and the NOx concentration at the inlet of the SCR reactor obtained at the fifth time before the fourth time, where a time difference between the fourth time and the fifth time is a second delay time.

And the identification purging module 420 is used for determining an outlet purging starting moment and an outlet purging ending moment of the outlet purging operation, and determining the last second ratio data calculated before the outlet purging starting moment as the outlet target ratio of the second purging operation.

And the measurement point replacing module 430 is used for taking the product of the SCR inlet NOx concentration and the outlet target ratio at the sixth moment before the current moment as the SCR outlet NOx replacing concentration when the outlet purging operation is executed, wherein the difference value between the current moment and the second delay time is the sixth moment.

Further, the determining process of the second delay time includes:

determining a NOx concentration change curve segment at the inlet of the SCR reactor according to the data of the NOx concentration at the inlet of the SCR reactor from the time t3 to the time t4, and determining a NOx concentration change curve segment at the outlet of the SCR reactor according to the data of the NOx concentration at the outlet of the SCR reactor from the time t3 to the time t 4; fitting the SCR reactor inlet NOx concentration change curve segment and the SCR reactor outlet NOx concentration change curve segment to obtain an SCR reactor inlet NOx concentration second change curve segment and an SCR reactor outlet NOx concentration second change curve segment which have consistent change trends; the time interval between the starting point of the second curve segment of the SCR reactor inlet NOx concentration and the starting point of the second curve segment of the SCR reactor outlet NOx concentration is determined as the second delay time.

Further, the control device is further configured to: adjusting the flow of ammonia entering the SCR reactor according to the concentration of NOx at the inlet of the SCR reactor obtained in real time; and according to the NOx substitution concentration at the outlet of the SCR reactor, the flow of the ammonia gas entering the SCR reactor is subjected to feedback regulation.

According to the technical scheme of the embodiment, the NOx substitute concentration during the period that the outlet of the SCR reactor is purged is obtained according to the relation between the concentration of the NOx at the inlet of the SCR reactor and the concentration of the NOx at the outlet of the SCR reactor, the problem that the concentration of the NOx at the outlet of the SCR reactor cannot be accurately measured during purging is solved, and the stability and the safety of an SCR denitration system are improved.

EXAMPLE six

The sixth embodiment of the invention provides a denitration control system, which comprises a hearth, an ammonia injection device, an economizer, an SCR reactor, an air preheater, a CEMS and the control device provided by the embodiment 4 or the embodiment 5. The embodiment can provide the denitration control system based on the SCR for the coal-fired power plant, which has higher stability and safety based on the embodiment.

Fig. 9 is a schematic structural diagram of a denitration control system according to a sixth embodiment of the present invention, which mainly includes a furnace 51, an economizer 52, an ammonia injection device 53, an SCR reactor 54, an air preheater 55, a CEMS56, and a control device 57.

It should be noted that the drawings only show the configuration of the denitration control system related to the present embodiment, and not all the configurations, for example, a desulfurization device, a dust removal device, and the like may be provided after the air preheater. The furnace 51, the economizer 52, the SCR reactor 54, and the air preheater 55 are connected by a flue, the CEMS56 mainly comprises a first flue gas sampling probe 561 at an inlet of the SCR reactor 54, a second flue gas sampling probe 561 at an outlet of the SCR reactor 54, a first purge controller 564, a second purge controller 564 ', a transmission cable 562, and an analysis processing device 563, which correspond to the first flue gas sampling probe 561 and the second flue gas sampling probe 561', respectively, and the transmission cable 562 connects the first flue gas sampling probe 561, the second flue gas sampling probe 561 ', the first purge controller 564, the second purge controller 564', and the analysis processing device 563, and is configured to transmit flue gas data acquired by the flue gas sampling probe 561 to the analysis processing device 563 for analysis processing, so as to obtain information such as NOx concentration in flue gas, which is acquired by the control device 57. Control 57 includes a calculate ratio module 571, an identify purge module 572, and a station replacement module 573. The control device 57 is connected to the CEMS56 and the ammonia injection device 53.

Taking the example that the inlet of the SCR reactor is purged, during the non-purging period, the ratio calculating module 571 may obtain the wind-coal ratio of the furnace 51 and the NOx concentration at the inlet of the SCR reactor 54 in real time, calculate a first ratio between the NOx concentration at the inlet of the SCR reactor 54 obtained at a first time and the wind-coal ratio obtained at a second time before the first time, where a time difference between the first time and the second time is a first delay time; when the first purge controller 564 performs the inlet purge of the SCR reactor 54, the recognize purge module 572 may obtain an inlet purge start time and an inlet purge end time of the inlet purge operation, and determine the last first ratio data calculated before the purge start time as an inlet target ratio of the inlet purge operation, the measure point substitution module 573 is configured to calculate an SCR reactor inlet NOx substitution concentration, and then transmit the SCR reactor inlet NOx substitution concentration to the ammonia injection device 53, and the ammonia injection device 53 adjusts the ammonia injection amount according to the SCR reactor inlet NOx substitution concentration.

The second purge controller 564 'purges the outlet of the SCR reactor 54 and the simultaneous purges of the first and second purge controllers 564, 564' are similar to the process described above and will not be discussed in detail.

The denitration control system provided in the above embodiment may execute the control method of the denitration control system provided in any embodiment of the present invention, and has corresponding advantageous effects of executing the method.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A control method of a denitration control system is characterized in that the denitration control system comprises a Selective Catalytic Reduction (SCR) denitration system and an automatic flue gas monitoring system (CEMS), the SCR denitration system comprises an SCR reactor, and the CEMS comprises a first purging controller arranged at an inlet of the SCR reactor and a second purging controller arranged at an outlet of the SCR reactor;

the control method comprises the following steps:

2. The control method according to claim 1, wherein the determination process of the first delay time includes:

3. The control method according to claim 1, characterized by further comprising:

when the first blowing controller is not controlled to execute the inlet blowing operation, adjusting the flow of ammonia entering the SCR reactor according to the concentration of NOx at the inlet of the SCR reactor obtained in real time;

and when the first purging controller is controlled to execute the inlet purging operation, regulating the flow of the ammonia gas entering the SCR reactor according to the NOx substitute concentration at the inlet of the SCR reactor.

4. The control method according to claim 1, characterized by further comprising:

5. The control method according to claim 4, wherein the determination process of the second delay time includes:

6. The control method according to claim 4, characterized by further comprising:

7. The control method according to claim 6, characterized by further comprising:

adjusting the flow of ammonia gas entering the SCR reactor according to the NOx substitute concentration at the inlet of the SCR reactor;

and according to the NOx substitute concentration at the outlet of the SCR reactor, the flow of ammonia entering the SCR reactor is subjected to feedback regulation.

8. A control method of a denitration control system is characterized in that the denitration control system comprises a Selective Catalytic Reduction (SCR) denitration system and an automatic flue gas monitoring system (CEMS), the SCR denitration system comprises an SCR reactor, and the CEMS comprises a first purging controller arranged at an inlet of the SCR reactor and a second purging controller arranged at an outlet of the SCR reactor;

the control method comprises the following steps:

9. The control method according to claim 8, wherein the determination process of the second delay time includes:

10. The control method according to claim 8, characterized by further comprising:

adjusting the flow of ammonia entering the SCR reactor according to the concentration of NOx at the inlet of the SCR reactor obtained in real time;

11. A control device of a denitration control system, comprising:

12. A control device of a denitration control system, comprising:

13. A denitration control system comprising a selective catalytic reduction, SCR, denitration system and an automatic flue gas monitoring system, CEMS, the SCR denitration system comprising an SCR reactor, the CEMS comprising a first purge controller disposed at an inlet of the SCR reactor, a second purge controller disposed at an outlet of the SCR reactor, and the control apparatus of claim 11 or 12.