A gas online analysis system and adaptive pretreatment method for industrial furnaces and devices
The gas online analysis system with UV and infrared sensors accurately detects nitrogen oxide concentrations and adjusts ammonia levels in industrial furnaces, addressing the inaccuracy and pollution issues of existing methods by ensuring precise ammonia dosing, effectively reducing nitrogen oxide formation.
Patent Information
- Application Number
- CN202411348794.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-03-25
- Estimated Expiration
- 2044-09-26
AI Technical Summary
In industrial furnaces, existing methods for detecting and adjusting ammonia levels to reduce nitrogen oxide formation are inaccurate due to rapid gas flow and uneven distribution, leading to potential ammonia 'escape' and environmental pollution.
A gas online analysis system with a self-adaptive preprocessing method, utilizing a combination of UV and infrared sensors to accurately detect nitrogen oxide concentrations and adjust ammonia levels in real-time, ensuring precise matching of ammonia to nitrogen oxide levels in the reaction container.
The system achieves precise detection and adjustment of ammonia levels, preventing ammonia over or under-dosing, thereby reducing nitrogen oxide formation and environmental pollution effectively.
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Figure CN119104511B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of gas analysis, and in particular to an online gas analysis system and an adaptive preprocessing method for industrial furnaces and devices. Background Art
[0002] In the high temperature combustion environment of industrial furnaces, nitrogen (N 2 ) can react with oxygen (O 2 ) react to produce nitrogen oxides (NO and NO 2 ), these nitrogen oxides are the main pollutants. By adding ammonia (NH 3 ) as a reducing agent can promote the reduction reaction and reduce the generation of nitrogen oxides.
[0003] In the prior art, NO and NO are detected by passing the gas through an ultraviolet light source after the gas is in a relatively static state and detecting the degree of absorption of the gas by ultraviolet light of a specific wavelength. 2 concentration. Due to the uneven distribution of nitrogen oxides in industrial kilns, it is difficult to accurately grasp the amount of ammonia by traditional detection methods. If the detection is in the transport pipeline, the detection is also inaccurate because the gas flow rate is too fast. If the ammonia is excessive in the reaction, it may cause "ammonia escape" during the circulation process, thereby polluting the environment. Due to the continuous discharge of exhaust gas and continuous introduction of circulating air in the kiln, the existing ammonia concentration adjustment method appears to be lagging behind. Therefore, it is necessary to design a gas online analysis system and adaptive pretreatment method that accurately matches industrial kilns and devices. Summary of the invention
[0004] The object of the present invention is to provide a gas online analysis system and an adaptive pretreatment method for industrial kilns and devices to solve the problems raised in the above background technology.
[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a gas online analysis system and an adaptive pretreatment method for an industrial kiln and device, comprising a pollutant concentration detection module, an exhaust gas flow observation module, and an adaptive analysis module, wherein the pollutant concentration detection module is used to detect the nitrogen oxide concentration in the kiln using an ultraviolet light detector, the exhaust gas flow observation module is used to detect the exhaust gas flow path in the kiln using an infrared sensing method, and the adaptive analysis module is used to combine the two detection methods to specifically determine the nitrogen oxide concentration currently flowing into the reaction container, and to fine-tune the nitrogen oxide concentration analysis result of the reaction container.
[0006] According to the above technical solution, the pollutant concentration detection module includes an ultraviolet light detector array, a vacuum pump, a flow calculation module, and a nitrogen oxide concentration recording module. The ultraviolet light detector array is electrically connected to the nitrogen oxide concentration recording module. The flow calculation module is installed in the gas channel of the vacuum pump. The ultraviolet light detector array is composed of a plurality of ultraviolet light detectors and a plurality of corresponding ultraviolet light sources, and is evenly distributed on the top inner wall of the kiln.
[0007] The ultraviolet detector array is used to detect the concentration of nitrogen oxides at different positions in the kiln, the vacuum pump is used to pump exhaust gas into the reaction container, the flow calculation module is used to calculate the flow rate pumped by the exhaust gas pump according to the gas flow rate of the vacuum pump, and the nitrogen oxide concentration recording module is used to calculate the nitrogen oxide concentration according to the detection result of the ultraviolet detector array;
[0008] The exhaust gas flow observation module includes an infrared sensing device, a digital temperature imaging module, an imaging display module, a flow path depiction module, and a concentration corresponding module. The infrared sensing device is electrically connected to the digital temperature imaging module, the digital temperature imaging module is electrically connected to the imaging display module, the imaging display module is electrically connected to the flow path depiction module, and the flow path depiction module is electrically connected to the concentration corresponding module.
[0009] The infrared sensing device is installed above the exhaust gas gathering place in the kiln, and is used to detect the concentration of nitrogen oxides by infrared sensing. The digital temperature imaging module is used to digitally image the signal detected by the infrared sensing device. The imaging display module is used to distinguish and display the digital imaging according to the different concentrations of nitrogen oxides. The flow path depiction module is used to depict the flow path of the exhaust gas from the kiln to the vacuum pump according to the changes in the infrared digital imaging. The concentration corresponding module is used to correspond the nitrogen oxide concentration at the connection between the kiln and the vacuum pump according to the current flow path of the exhaust gas;
[0010] The adaptive analysis module includes a time accumulation unit, a data reading module, an information storage module, a concentration detector, a nitrogen oxide concentration verification module, and an ammonia concentration adaptation module. The data reading module is electrically connected to the concentration corresponding module and the nitrogen oxide concentration recording module, the information storage module is electrically connected to the data reading module and the concentration detector, the time accumulation unit is electrically connected to the flow calculation module, the nitrogen oxide concentration verification module is electrically connected to the information storage module, and the ammonia concentration adaptation module is electrically connected to the nitrogen oxide concentration verification module;
[0011] The concentration detector is installed at the inlet end of the reaction container and is used to detect the concentration of nitrogen oxides flowing into the reaction container. The time accumulation unit is used to count the time of exhaust gas flowing in different stages. The data reading module is used to receive the nitrogen oxide concentration detection signal. The information storage module is used to store nitrogen oxide concentration data. The nitrogen oxide concentration verification module is used to verify whether the nitrogen oxide concentration signal calculated in advance is correct. The ammonia concentration adaptation module is used to adjust the concentration of ammonia introduced into the reaction container to adapt to the nitrogen oxide concentration in the exhaust gas.
[0012] According to the above technical solution, the adaptive preprocessing method of the system is:
[0013] S0. Install an array of ultraviolet detectors at multiple parallel positions at the exhaust gas gathering place on the top of the kiln, so that the array of ultraviolet detectors can be wrapped by the exhaust gas when in use, and install a concentration detector at the entrance of the reaction container, and install an infrared sensing device in the space above the exhaust gas in the kiln;
[0014] S1. Start the kiln and discharge the exhaust gas normally, use the ultraviolet detector array to detect the nitrogen oxide concentration at different positions in the kiln, and use the digital temperature imaging module to depict the exhaust gas flow path in the plane;
[0015] S2. Real-time tracking and display of the moving path of the digital imaging. When the digital imaging of a certain area moves to the position of the kiln exhaust port, it means that the exhaust gas corresponding to the current digital imaging position is pumped into the reaction vessel. The nitrogen oxide concentration detected by the ultraviolet detector at this position is clear, and the nitrogen oxide concentration at the inlet of the current reaction vessel is calculated in advance according to the flow rate and time of the exhaust gas.
[0016] S3, using the nitrogen oxide concentration detected by the concentration detector to check the nitrogen oxide concentration calculated in advance, and adjusting the calculation result of the nitrogen oxide concentration at the inlet of the reaction container calculated in advance according to the check result;
[0017] S4. According to the nitrogen oxide concentration at the inlet of the reaction container calculated in advance, the ammonia concentration of the reaction container is adapted accordingly, so that when the exhaust gas here reaches the inlet of the reaction container, it can match the correct ammonia concentration, and the ammonia concentration of the reaction container is verified.
[0018] According to the above technical solution, in S1, the specific detection method of nitrogen oxide concentration at different positions in the kiln is:
[0019] S1-1. Identify the wavelength absorption peaks of the ultraviolet absorption spectra of nitric oxide and nitrogen dioxide, where nitric oxide is a and nitrogen dioxide is b, and use an ultraviolet light source to emit ultraviolet light of specific wavelengths a and b;
[0020] S1-2. Use an ultraviolet light detector to detect the absorption intensity at different wavelengths. The absorption intensity of nitric oxide is c 1a The absorption intensity of nitrogen dioxide is c 1b , combined with the rated emission intensity of the UV light source c 0 , obtain the absorption spectrum characteristics of the gas, where the absorption rate of nitric oxide is The absorption rate of nitrogen dioxide is
[0021] S1-3. Calculate the concentration of nitric oxide and nitrogen dioxide based on the absorption rate, where the concentration of nitric oxide is The concentration of nitrogen dioxide is Where α is the conversion factor between ultraviolet light absorbance and concentration.
[0022] According to the above technical solution, in S2, the specific method for calculating the nitrogen oxide concentration at the current reaction container inlet in advance is: when a certain exhaust gas corresponding to the location of a certain ultraviolet light detector flows out of the kiln exhaust port, record the time node t 0 , the flow rate from the kiln exhaust port to the reaction vessel inlet is V through volume measurement, and the flow calculation module records the gas flow rate of the vacuum pump as v, then the time node t 0 The corresponding time for the exhaust gas to flow into the inlet of the reaction vessel is The carbon monoxide concentration and carbon dioxide concentration measured at this time point are marked as the nitrogen oxide concentration calculated in advance.
[0023] According to the above technical solution, in S3, the specific method for verifying the nitrogen oxide concentration calculated in advance is: record The carbon monoxide concentration G detected by the concentration detector at the time node a and carbon dioxide concentration G b , traced back to the stored t 0 Calculated concentration of nitric oxide at a given time point and the concentration of nitrogen dioxide is The NO concentration deviation coefficient and nitrogen dioxide The concentrations of nitric oxide and nitrogen dioxide measured at subsequent time points should be divided by μ a and μ b Thus, verification is carried out.
[0024] According to the above technical solution, in S4, the specific method for adapting the ammonia concentration is: determining the ammonia concentrations required for the reduction reaction of nitric oxide and nitrogen dioxide according to the chemical reaction equation, wherein the ammonia concentration that reacts with nitric oxide is The concentration of ammonia that reacts with nitrogen dioxide is where γ a The number of parts of ammonia required to produce one part of nitric oxide, γ b The number of parts of ammonia required for one part of nitrogen dioxide, the required ammonia concentration is W = W a +W b .
[0025] According to the above technical solution, in S4, the specific method for verifying the ammonia concentration of the reaction container is: in the waste gas discharged from the reaction container after the reduction reaction, it is necessary to detect a concentration lower than the concentration threshold W 0 If the ammonia concentration is higher than the concentration threshold, the ammonia concentration introduced into the reaction container needs to be reduced. If nitrogen oxide residues are detected in the exhaust gas after the reduction, the reaction conditions of the reaction container need to be improved.
[0026] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the present invention detects the concentrations of nitric oxide and nitrogen dioxide in the exhaust gas of the kiln by ultraviolet spectroscopy detection, and detects the flow path of the exhaust gas by infrared detection, so as to clarify the concentrations of nitric oxide and nitrogen dioxide flowing out of the kiln, achieving the effect of accurate detection, overcoming the problem of inaccurate nitrogen content detection under fast-flowing gas, and adopting the method of advance calculation, the exhaust gas can just match the appropriate concentration of ammonia when it flows into the reaction container, and will not cause the problem of excessive or insufficient ammonia. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.
[0028] In the attached picture:
[0029] Figure 1 It is a schematic diagram of the overall module structure of the present invention;
[0030] Figure 2 It is a module tree diagram of the present invention. DETAILED DESCRIPTION
[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0032] See also Figure 1-Figure 2The present invention provides a technical solution: a gas online analysis system and an adaptive pretreatment method for an industrial kiln and device, comprising a pollutant concentration detection module, an exhaust gas flow observation module, and an adaptive analysis module, wherein the pollutant concentration detection module is used to detect the nitrogen oxide concentration in the kiln by using an ultraviolet light detector, the exhaust gas flow observation module is used to detect the exhaust gas flow path in the kiln by using an infrared sensing method, and the adaptive analysis module is used to specifically determine the nitrogen oxide concentration currently flowing into the reaction container by combining the two detection methods, and to fine-tune the nitrogen oxide concentration analysis result of the reaction container;
[0033] The pollutant concentration detection module includes an ultraviolet detector array, a vacuum pump, a flow calculation module, and a nitrogen oxide concentration recording module. The ultraviolet detector array is electrically connected to the nitrogen oxide concentration recording module. The flow calculation module is installed in the gas channel of the vacuum pump. The ultraviolet detector array is composed of a plurality of ultraviolet detectors and a plurality of corresponding ultraviolet light sources, and is evenly distributed on the top inner wall of the kiln.
[0034] The ultraviolet detector array is used to detect the concentration of nitrogen oxides at different positions in the kiln, the vacuum pump is used to pump exhaust gas into the reaction container, the flow calculation module is used to calculate the flow rate pumped by the exhaust gas pump according to the gas flow rate of the vacuum pump, and the nitrogen oxide concentration recording module is used to calculate the nitrogen oxide concentration according to the detection result of the ultraviolet detector array;
[0035] The exhaust gas flow observation module includes an infrared sensing device, a digital temperature imaging module, an imaging display module, a flow path depiction module, and a concentration corresponding module. The infrared sensing device is electrically connected to the digital temperature imaging module, the digital temperature imaging module is electrically connected to the imaging display module, the imaging display module is electrically connected to the flow path depiction module, and the flow path depiction module is electrically connected to the concentration corresponding module.
[0036] The infrared sensing device is installed above the exhaust gas gathering place in the kiln, and is used to detect the concentration of nitrogen oxides by infrared sensing. The digital temperature imaging module is used to digitally image the signal detected by the infrared sensing device. The imaging display module is used to distinguish and display the digital imaging according to the different concentrations of nitrogen oxides. The flow path depiction module is used to depict the flow path of the exhaust gas from the kiln to the vacuum pump according to the changes in the infrared digital imaging. The concentration corresponding module is used to correspond the nitrogen oxide concentration at the connection between the kiln and the vacuum pump according to the current flow path of the exhaust gas;
[0037] The adaptive analysis module includes a time accumulation unit, a data reading module, an information storage module, a concentration detector, a nitrogen oxide concentration verification module, and an ammonia concentration adaptation module. The data reading module is electrically connected to the concentration corresponding module and the nitrogen oxide concentration recording module, the information storage module is electrically connected to the data reading module and the concentration detector, the time accumulation unit is electrically connected to the flow calculation module, the nitrogen oxide concentration verification module is electrically connected to the information storage module, and the ammonia concentration adaptation module is electrically connected to the nitrogen oxide concentration verification module;
[0038] The concentration detector is installed at the inlet end of the reaction container, and is used to detect the concentration of nitrogen oxides flowing into the reaction container. The time accumulation unit is used to count the time of exhaust gas flowing in different stages. The data reading module is used to receive the nitrogen oxide concentration detection signal. The information storage module is used to store the nitrogen oxide concentration data. The nitrogen oxide concentration verification module is used to verify whether the nitrogen oxide concentration signal calculated in advance is correct. The ammonia concentration adaptation module is used to adjust the concentration of ammonia introduced into the reaction container to adapt to the nitrogen oxide concentration in the exhaust gas.
[0039] The adaptive preprocessing method of this system is:
[0040] S0. Install an array of ultraviolet detectors at multiple parallel positions at the exhaust gas gathering place on the top of the kiln, so that the array of ultraviolet detectors can be wrapped by the exhaust gas when in use, and install a concentration detector at the entrance of the reaction container, and install an infrared sensing device in the space above the exhaust gas in the kiln;
[0041] S1. Start the kiln and discharge the exhaust gas normally, use the ultraviolet detector array to detect the nitrogen oxide concentration at different positions in the kiln, and use the digital temperature imaging module to depict the exhaust gas flow path in the plane;
[0042] S2. Real-time tracking and display of the moving path of the digital imaging. When the digital imaging of a certain area moves to the position of the kiln exhaust port, it means that the exhaust gas corresponding to the current digital imaging position is pumped into the reaction vessel. The nitrogen oxide concentration detected by the ultraviolet detector at this position is clear, and the nitrogen oxide concentration at the inlet of the current reaction vessel is calculated in advance according to the flow rate and time of the exhaust gas.
[0043] S3, using the nitrogen oxide concentration detected by the concentration detector to check the nitrogen oxide concentration calculated in advance, and adjusting the calculation result of the nitrogen oxide concentration at the inlet of the reaction container calculated in advance according to the check result;
[0044] S4. Adapting the ammonia concentration of the reaction container accordingly according to the nitrogen oxide concentration at the inlet of the reaction container calculated in advance, so that when the exhaust gas at this place reaches the inlet of the reaction container, it can match the correct ammonia concentration, and verifying the ammonia concentration of the reaction container;
[0045] In S1, the specific detection method of nitrogen oxide concentration at different positions in the kiln is:
[0046] S1-1. Identify the wavelength absorption peaks of the ultraviolet absorption spectra of nitric oxide and nitrogen dioxide, where nitric oxide is a and nitrogen dioxide is b, and use an ultraviolet light source to emit ultraviolet light of specific wavelengths a and b;
[0047] S1-2. Use an ultraviolet light detector to detect the absorption intensity at different wavelengths. The absorption intensity of nitric oxide is c 1a The absorption intensity of nitrogen dioxide is c 1b , combined with the rated emission intensity of the UV light source c 0 , obtain the absorption spectrum characteristics of the gas, where the absorption rate of nitric oxide is The absorption rate of nitrogen dioxide is
[0048] S1-3. Calculate the concentration of nitric oxide and nitrogen dioxide based on the absorption rate, where the concentration of nitric oxide is The concentration of nitrogen dioxide is Where α is the conversion factor between UV absorbance and concentration;
[0049] In S2, the specific method for calculating the nitrogen oxide concentration at the inlet of the current reaction container in advance is: when the exhaust gas at a certain location corresponding to the location of a certain ultraviolet light detector flows out of the kiln exhaust port, record the time node t 0 , the flow rate from the kiln exhaust port to the reaction vessel inlet is V through volume measurement, and the flow calculation module records the gas flow rate of the vacuum pump as v, then the time node t 0 The corresponding time for the exhaust gas to flow into the inlet of the reaction vessel is The carbon monoxide concentration and carbon dioxide concentration measured at this time point are marked as the nitrogen oxide concentration calculated in advance;
[0050] In S3, the specific method for verifying the nitrogen oxide concentration calculated in advance is: record The carbon monoxide concentration G detected by the concentration detector at the time node a and carbon dioxide concentration G b , traced back to the stored t 0 Calculated concentration of nitric oxide at a given time point and the concentration of nitrogen dioxide is The NO concentration deviation coefficient and nitrogen dioxide The concentrations of nitric oxide and nitrogen dioxide measured at subsequent time points should be divided by μ a and μ b Thus, verification is carried out;
[0051] In S4, the specific method for adapting the ammonia concentration is: according to the chemical reaction equation, the ammonia concentrations required for the reduction reaction of nitric oxide and nitrogen dioxide are determined, wherein the ammonia concentration that reacts with nitric oxide is The concentration of ammonia that reacts with nitrogen dioxide is where γ a The number of parts of ammonia required for one part of nitric oxide, γ b The number of parts of ammonia required for one part of nitrogen dioxide, the required ammonia concentration is W = W a +W b ;
[0052] In S4, the specific method for verifying the ammonia concentration of the reaction container is: the exhaust gas discharged from the reaction container after the reduction reaction needs to be detected to be lower than the concentration threshold value W 0 If the ammonia concentration is higher than the concentration threshold, the ammonia concentration introduced into the reaction container needs to be reduced. If nitrogen oxide residues are detected in the exhaust gas after the reduction, the reaction conditions of the reaction container need to be improved.
[0053] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.
[0054] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. An online gas analysis system for industrial kilns and devices, characterized by: It includes a pollutant concentration detection module, an exhaust gas flow observation module, and an adaptive analysis module. The pollutant concentration detection module is used to detect the nitrogen oxide concentration in the kiln by using an ultraviolet light detector, the exhaust gas flow observation module is used to detect the exhaust gas flow path in the kiln by using an infrared sensing method, and the adaptive analysis module is used to specifically determine the nitrogen oxide concentration currently flowing into the reaction container by combining the two detection methods, and to fine-tune the nitrogen oxide concentration analysis result of the reaction container; The pollutant concentration detection module includes an ultraviolet light detector array, which is electrically connected to the nitrogen oxide concentration recording module. The flow calculation module is installed in the gas channel of the vacuum pump. The ultraviolet light detector array is composed of a plurality of ultraviolet light detectors and a plurality of corresponding ultraviolet light sources, and is evenly distributed on the top inner wall of the kiln. The ultraviolet detector array is used to detect the concentration of nitrogen oxides at different positions in the kiln, the vacuum pump is used to pump exhaust gas into the reaction container, the flow calculation module is used to calculate the flow rate pumped by the exhaust gas pump according to the gas flow rate of the vacuum pump, and the nitrogen oxide concentration recording module is used to calculate the nitrogen oxide concentration according to the detection result of the ultraviolet detector array; The exhaust gas flow observation module includes an infrared sensing device, the infrared sensing device is electrically connected to the digital temperature imaging module, the digital temperature imaging module is electrically connected to the imaging display module, the imaging display module is electrically connected to the flow path depiction module, and the flow path depiction module is electrically connected to the concentration corresponding module; The infrared sensing device is installed above the exhaust gas gathering place in the kiln, and is used to detect the nitrogen oxide concentration by infrared sensing. The digital temperature imaging module is used to digitally image the signal detected by the infrared sensing device. The imaging display module is used to distinguish and display the digital imaging according to the different nitrogen oxide concentrations. The flow path depiction module is used to depict the flow path of the exhaust gas from the kiln to the vacuum pump according to the changes in the infrared digital imaging. The concentration corresponding module is used to correspond the nitrogen oxide concentration at the connection between the kiln and the vacuum pump according to the current exhaust gas flow path. The adaptive analysis module includes a time accumulation unit, a data reading module electrically connected to a concentration corresponding module and a nitrogen oxide concentration recording module, an information storage module electrically connected to a data reading module and a concentration detector, a time accumulation unit electrically connected to a flow calculation module, a nitrogen oxide concentration verification module electrically connected to an information storage module, and an ammonia concentration adaptation module electrically connected to a nitrogen oxide concentration verification module; The concentration detector is installed at the inlet end of the reaction container, and is used to detect the concentration of nitrogen oxides flowing into the reaction container. The time accumulation unit is used to count the time of exhaust gas flowing in different stages. The data reading module is used to receive the nitrogen oxide concentration detection signal. The information storage module is used to store the nitrogen oxide concentration data. The nitrogen oxide concentration verification module is used to verify whether the nitrogen oxide concentration signal calculated in advance is correct. The ammonia concentration adaptation module is used to adjust the concentration of ammonia introduced into the reaction container to adapt to the nitrogen oxide concentration in the exhaust gas. The specific method for calculating the nitrogen oxide concentration at the current reaction vessel inlet in advance is: when the exhaust gas at a certain location corresponding to the location of a certain ultraviolet detector flows out of the kiln exhaust port, record the time node , the flow rate from the kiln exhaust port to the reaction vessel inlet is obtained through volume measurement: , the flow calculation module records the gas flow rate of the vacuum pump as , then the time node The corresponding time for the exhaust gas to flow into the inlet of the reaction vessel is , marking the carbon monoxide concentration and carbon dioxide concentration measured at this time node as the nitrogen oxide concentration calculated in advance; The specific method for checking the pre-calculated nitrogen oxide concentration is as follows: record The carbon monoxide concentration detected by the concentration detector at the time node and carbon dioxide concentration , traced back to the stored Calculated concentration of nitric oxide at a given time point and the concentration of nitrogen dioxide is , and the NO concentration deviation coefficient is obtained , and nitrogen dioxide The concentrations of nitric oxide and nitrogen dioxide measured at subsequent time points should be divided by and Thus, verification is carried out.
2. The gas online analysis system for industrial kilns and devices according to claim 1, characterized in that: The adaptive preprocessing method of this system is: S0. Install an array of ultraviolet detectors at multiple parallel positions at the exhaust gas gathering place on the top of the kiln, so that the array of ultraviolet detectors can be wrapped by the exhaust gas when in use, and install a concentration detector at the entrance of the reaction container, and install an infrared sensing device in the space above the exhaust gas in the kiln; S1. Start the kiln and discharge the exhaust gas normally, use the ultraviolet detector array to detect the nitrogen oxide concentration at different positions in the kiln, and use the digital temperature imaging module to depict the exhaust gas flow path in the plane; S2. Real-time tracking and display of the moving path of the digital imaging. When the digital imaging of a certain area moves to the position of the kiln exhaust port, it means that the exhaust gas corresponding to the current digital imaging position is pumped into the reaction vessel. The nitrogen oxide concentration detected by the ultraviolet detector at this position is clear, and the nitrogen oxide concentration at the inlet of the current reaction vessel is calculated in advance according to the flow rate and time of the exhaust gas. S3, using the nitrogen oxide concentration detected by the concentration detector to check the nitrogen oxide concentration calculated in advance, and adjusting the calculation result of the nitrogen oxide concentration at the inlet of the reaction container calculated in advance according to the check result; S4. According to the nitrogen oxide concentration at the inlet of the reaction container calculated in advance, the ammonia concentration of the reaction container is adapted accordingly, so that when the exhaust gas here reaches the inlet of the reaction container, it can match the correct ammonia concentration, and the ammonia concentration of the reaction container is verified.
3. The gas online analysis system for industrial kilns and devices according to claim 2, characterized in that: In S1, the specific detection method of nitrogen oxide concentration at different positions in the kiln is: S1-1. Clarify the wavelength absorption peaks of the ultraviolet absorption spectra of nitric oxide and nitrogen dioxide, among which nitric oxide is , nitrogen dioxide is , using ultraviolet light sources to emit specific wavelengths and of ultraviolet light; S1-2. Use an ultraviolet light detector to detect the absorption intensity at different wavelengths. The absorption intensity of nitric oxide is The absorption intensity of nitrogen dioxide is , combined with the rated emission intensity of the UV light source , obtain the absorption spectrum characteristics of the gas, where the absorption rate of nitric oxide is The absorption rate of nitrogen dioxide is ; S1-3. Calculate the concentration of nitric oxide and nitrogen dioxide based on the absorption rate, where the concentration of nitric oxide is The concentration of nitrogen dioxide is ,in It is the conversion factor between UV absorbance and concentration.
4. The gas online analysis system for industrial kilns and devices according to claim 3 is characterized by: In S4, the specific method for adapting the ammonia concentration is: determining the ammonia concentrations required for the reduction reaction of nitric oxide and nitrogen dioxide according to the chemical reaction equation, wherein the ammonia concentration that reacts with nitric oxide is , the concentration of ammonia that reacts with nitrogen dioxide is ,in The number of parts of ammonia required to produce one part of nitric oxide, The number of parts of ammonia required for one part of nitrogen dioxide, the required ammonia concentration is .
5. The gas online analysis system for industrial kilns and devices according to claim 4, characterized in that: In S4, the specific method for verifying the ammonia concentration of the reaction container is: the exhaust gas discharged from the reaction container after the reduction reaction needs to be detected to be lower than the concentration threshold. If the ammonia concentration is higher than the concentration threshold, the ammonia concentration introduced into the reaction container needs to be reduced. If nitrogen oxide residues are detected in the exhaust gas after the reduction, the reaction conditions of the reaction container need to be improved.
Citation Information
Patent Citations
Gas detection method and apparatus
CN105823754A