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CN-117482744-B - Control method for ammonia water injection in SCR denitration of garbage incinerator

CN117482744BCN 117482744 BCN117482744 BCN 117482744BCN-117482744-B

Abstract

The application discloses a control method for ammonia water injection in SCR denitration of a garbage incinerator, which relates to the technical field of environmental protection engineering and comprises the steps of detecting flue gas flow, flue gas temperature, flue gas pressure and nitrogen oxide concentration at an inlet of a flue gas reactor, detecting an absolute temperature distribution image of a cross section of an ammonia water injection layer of the reactor, converting the absolute temperature distribution image into an absolute temperature distribution contour map of the cross section, detecting a nitrogen oxide concentration distribution map of the cross section of the ammonia water injection layer of the reactor, converting the nitrogen oxide concentration distribution map of the cross section into a concentration distribution contour map of the cross section, determining an optimal denitration reduction temperature line, adjusting the number and the injection quantity of core positions of spray heads corresponding to temperatures according to the nitrogen oxide concentration distribution contour map, fitting deamination efficiency under different working conditions through a random forest algorithm, performing parameter tuning on a trained model, optimizing the use of ammonia water under different working conditions through a genetic algorithm, and finding the optimal ammonia injection quantity under the corresponding working conditions.

Inventors

  • ZHANG JUN
  • SUN YANZHEN
  • YU ZHONGQING

Assignees

  • 青岛洪锦智慧能源技术有限公司

Dates

Publication Date
20260512
Application Date
20231103

Claims (4)

  1. 1. The control method for ammonia water injection in SCR denitration of the garbage incinerator is characterized by comprising the following steps of: Detecting the flow rate, the temperature, the pressure and the concentration of nitrogen oxides of the flue gas at the inlet of the reactor to obtain initial detection parameters; Based on initial parameters, obtaining an absolute temperature distribution image of a cross section of the ammonia water jet layer of the reactor according to the initial parameters of the flue gas temperature, and converting the absolute temperature distribution image into an absolute temperature distribution contour map of the cross section; step (3), determining an optimal denitration reduction temperature line based on the step (2), wherein the neighborhood of the line is an optimal ammonia denitration zone; Step (4), obtaining a nitrogen oxide concentration distribution map of a cross section of the ammonia water jet layer of the reactor according to the concentration of the nitrogen oxide based on the initial parameters detected in the step (1), and converting the nitrogen oxide concentration distribution map into a concentration distribution contour map of the cross section; Step (5), according to the concentration distribution contour diagram of the nitrogen oxides, the quantity and the spraying quantity of core positions of the corresponding temperature of the spray head are adjusted; Fitting deamination efficiency under different working conditions through a random forest algorithm, and performing parameter tuning on a trained model; and (7) optimizing the use of ammonia water under different working conditions through a genetic algorithm, and finding out the optimal ammonia spraying amount under the corresponding working conditions.
  2. 2. The method for controlling ammonia water injection in SCR denitration of garbage incinerator according to claim 1, wherein the cross section absolute temperature distribution contour map obtained in step (2), step (3) determines an optimal denitration reduction temperature line, and the neighborhood of the line is the optimal denitration zone of ammonia water; according to the chemical reaction occurring in the SCR denitration process, When the temperature is 350-390 ℃, the reaction is more sufficient, and the utilization rate of ammonia water in the reaction is higher, so that the temperature in the cross section absolute temperature contour map needs to be distinguished.
  3. 3. The control method for ammonia water injection in SCR denitration of garbage incinerator according to claim 1, wherein the cross section nitrogen oxide concentration profile obtained in step (4) is a contour map, and step (5) is to adjust the number and the injection quantity of core positions of the nozzle corresponding to the temperature; According to the nitrogen oxide concentration distribution contour map, different concentrations are partitioned into three areas, namely a high concentration area, a medium concentration area and a low concentration area according to actual conditions, spray heads with different data volumes are respectively adjusted in the three different areas, the spray heads are partitioned according to the proportion of the high, medium and low areas being 5:4:3, and the valve opening of the spray heads is adjusted according to the opening of the high, medium and low areas being high, medium and low.
  4. 4. The method for controlling ammonia water injection in SCR denitration of garbage incinerator according to claim 1, wherein the step (6) and the step (7) are performed with control of ammonia injection amount according to different working conditions, so that corresponding data under various working conditions need to be collected, the data analysis and the data cleaning are performed, a model is obtained through fitting learning, and the optimal ammonia injection amount under the corresponding working conditions is obtained by optimizing the ammonia injection amount.

Description

Control method for ammonia water injection in SCR denitration of garbage incinerator Technical Field The application relates to the technical field of environmental protection engineering, in particular to a control method for ammonia water injection in SCR denitration of a garbage incinerator. Background The nitrogen oxides generated in the garbage incineration process are important components causing the atmospheric pollution, and the nitrogen oxides mainly comprise nitrogen oxides such as NO, NO2, N2O, N O3, N2O4, N2O5 and the like, wherein the main components are NO and NO2. Denitration of garbage incinerator is divided into two kinds according to denitration technology, namely denitration in incinerator incineration process (SNCR for short) and flue gas denitration (SCR for short). SCR reliability is high, denitration efficiency is high, operation and maintenance are complex, operation cost is high, SNCR operation and maintenance are simple, operation cost is low, and denitration efficiency is low. The reductant of SCR denitration systems is ammonia, which generally has three sources, namely liquid ammonia, urea and aqueous ammonia. The transportation and the use of the liquid ammonia are cheaper, but the liquid ammonia is toxic and needs to be stored under high pressure, the transportation and the use of the ammonia water are more expensive, the liquid ammonia is harmless and stored under normal atmospheric pressure, the urea is most expensive, and the transportation cost is cheap and harmless and stored under normal atmospheric pressure. The most widely used liquid ammonia in China is used as a reducing agent of an SCR denitration system. The SCR denitration technology calculates the quantity of the reducing agent required under the corresponding working condition according to the content of nitrogen oxides in the measured flue gas, the flow rate of the flue gas and the temperature, denitration reaction is carried out in a denitration reactor, and the reducing agent carries out the reduction process on the passing flue gas through injection. The denitration reduction reaction efficiency of the SCR denitration system is higher at 300-400 ℃, and the corresponding reducing agent quantity needs to be timely adjusted according to different working conditions, otherwise, the reducing agent is not fully reacted, or the efficiency is reduced due to excessive reducing agent, and the waste of the reducing agent is caused. Control of SCR reductant is therefore critical to directly impact denitration efficiency. Disclosure of Invention In order to solve the problem of controlling the injection quantity of liquid ammonia, the method can be used for timely adjusting the quantity of the corresponding reducing agents according to different disclosures, and improving the denitration efficiency. The control method for ammonia water injection in SCR denitration of the garbage incinerator provided by the application adopts the following technical scheme. A control method for ammonia water injection in SCR denitration of a garbage incinerator comprises the following steps: Detecting the flow rate, the temperature, the pressure and the concentration of nitrogen oxides at the inlet of the reactor to obtain initial detection parameters; Based on the detected initial parameters, obtaining an absolute temperature distribution image of a cross section of the ammonia water jet layer of the reactor according to the initial parameters of the flue gas temperature, and converting the absolute temperature distribution image into an absolute temperature distribution contour map of the cross section; step (3), determining an optimal denitration reduction temperature line based on the step (2), wherein the neighborhood of the line is an optimal ammonia denitration zone; Step (4), obtaining a nitrogen oxide concentration distribution map of a cross section of the ammonia water jet layer of the reactor according to the concentration of the nitrogen oxide based on the initial parameters detected in the step (1), and converting the nitrogen oxide concentration distribution map into a concentration distribution contour map of the cross section; Step (5), according to the concentration distribution contour diagram of the nitrogen oxides, the quantity and the spraying quantity of core positions of the corresponding temperature of the spray head are adjusted; Fitting deamination efficiency under different working conditions through a random forest algorithm, and performing parameter tuning on a trained model; and (7) optimizing the use of ammonia water under different working conditions through a genetic algorithm, and finding out the optimal ammonia spraying amount under the corresponding working conditions. Optionally, the cross section absolute temperature distribution contour map obtained in the step (2), and determining an optimal denitration reduction temperature line in the step (3), wherein the neighborhood of the line is an ammonia wa