Boiler combustion atmosphere monitoring device

Abstract

The invention discloses a boiler combustion atmosphere monitoring device, and relates to the technical field of combustion monitoring, the boiler combustion atmosphere monitoring device comprises a base, the upper end of the base is provided with a filter, a heater and a controller, and the input end of the filter is provided with a sampling piece; the sampling piece comprises an air compressor and three Venturi tubes connected with the air compressor, and the input ends of the three Venturi tubes are sequentially and correspondingly provided with stainless steel tubes, hastelloy tubes and ceramic tubes for being connected with different positions of the boiler; the filter is communicated with the heater, three detection pipes are arranged at the output end of the heater, and an oxygen detection sensor, an infrared spectrum sensor and a hydrogen sulfide detection sensor are arranged in each detection pipe. According to the invention, the oxygen detection sensor, the infrared spectrum sensor and the hydrogen sulfide detection sensor are simultaneously arranged in the detection tube to respectively detect the concentrations of O2, various nitrogen oxides and H2S, so that the defect of monitoring pollutant emission by single oxygen analysis is overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of combustion monitoring, and in particular to a boiler combustion atmosphere monitoring device. Background Art

[0002] Exhaust gas detection is the data source and basic means for combustion control of various boilers, especially large boilers. In existing application reality, mainstream large boilers mainly rely on automatic measurement of oxygen content to create conditions for further combustion control and optimization.

[0003] However, in actual application, firstly, single monitoring is insufficient: simple oxygen measurement, that is, the absolute value of O2, and single oxygen analysis cannot meet the needs of environmental monitoring and control work; secondly, there is strong interference: the detection is too affected by other factors, such as the type of coal burned, boiler load, weather conditions, etc. Summary of the Invention

[0004] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract of the specification and the title of the invention of this application to avoid blurring the purpose of this section, the abstract of the specification and the title of the invention, and such simplifications or omissions cannot be used to limit the scope of the invention.

[0005] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A boiler combustion atmosphere monitoring device includes a base, wherein a filter, a heater and a controller are provided at the upper end of the base, and a sampling piece is provided at the input end of the filter; the sampling piece includes an air compressor and three venturi tubes connected thereto, and the input ends of the three venturi tubes are respectively provided with a stainless steel tube, a Hastelloy tube and a ceramic tube for connecting to different positions of the boiler; the filter is connected to the heater, and the output end of the heater is provided with three detection tubes, each of which is provided with an oxygen detection sensor, an infrared spectrum sensor and a hydrogen sulfide detection sensor.

[0008] Furthermore, an air compressor is fixed to one side of the filter through a bracket, an output end of the air compressor is connected to a conduit, and an instrument air duct is connected between one side of the conduit and the upper end of the venturi tube.

[0009] Furthermore, a flow sensor is provided in the instrument air duct.

[0010] Furthermore, one end of each of the venturi tubes is connected to the stainless steel tube, the Hastelloy tube and the ceramic tube in sequence through a flange.

[0011] Furthermore, pressure sensors are provided in the stainless steel tube, Hastelloy tube and ceramic tube.

[0012] Furthermore, three transmission tubes are provided between the output end of the filter and the input end of the heater, and the three transmission tubes are connected to the stainless steel tube, the Hastelloy tube and the ceramic tube in sequence through the filter.

[0013] Furthermore, one end of the stainless steel tube, the Hastelloy tube and the ceramic tube are connected to the three detection tubes in sequence through a filter and a heater.

[0014] Furthermore, each of the detection tubes is provided with a vanadium-tungsten-titanium catalytic layer and a zeolite molecular sieve layer, and both the vanadium-tungsten-titanium catalytic layer and the zeolite molecular sieve layer are honeycomb-shaped.

[0015] Furthermore, the vanadium-tungsten-titanium catalyst layer is located at the left end of the zeolite molecular sieve layer.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. Multi-parameter sensor integration: An oxygen detection sensor, an infrared spectrum sensor, and a hydrogen sulfide detection sensor are simultaneously installed in the detection tube to detect the concentrations of O2, various nitrogen oxides (such as NO, NO2, N2O), and H2S, respectively, forming a multi-pollutant coordinated monitoring system to make up for the shortcomings of single oxygen analysis in pollutant emission monitoring;

[0018] 2. Material-adaptable sampling tube: Select sampling tubes made of corrosion-resistant Hastelloy tubes, high-temperature-resistant ceramic tubes, and general-purpose stainless steel tubes according to different working conditions to reduce the interference of special environments on sampling stability and ensure measurement reliability;

[0019] 3. Multi-position sampling design: Sampling is performed simultaneously from different positions of the boiler through stainless steel tubes, Hastelloy tubes, and ceramic tubes. By combining data from multiple detection tubes, the distribution of pollutants in the combustion atmosphere is comprehensively monitored to avoid the risk of localized emissions exceeding standards.

[0020] 4. Catalytic reaction structure: The honeycomb vanadium-tungsten-titanium catalytic layer and zeolite molecular sieve layer in the detection tube catalytically treat the flue gas. By comparing the sensor data before and after catalysis, the pollutant conversion rate (such as NOx decomposition rate) is directly calculated, which promotes the reduction of NH3 and NOx emissions and provides a quantitative basis for environmental protection control.

[0021] Other features and advantages of the present application will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0022] The technical solution of the present application is further described in detail below through the accompanying drawings and examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 It is a front view schematic diagram of the present invention;

[0026] Figure 3 This is a schematic diagram of the sampling piece of the present invention;

[0027] Figure 4 For the present invention Figure 3 The enlarged schematic diagram of point a in the middle;

[0028] Figure 5 It is a top view schematic diagram of the present invention;

[0029] Figure 6 is a schematic cross-sectional view of a detection tube of the present invention;

[0030] Figure: 1. Base; 2. Filter; 3. Heater; 4. Sampling element; 41. Venturi tube; 42. Air compressor; 43. Conduit; 44. Instrument air duct; 45. Flow sensor; 5. Stainless steel tube; 6. Detection tube; 7. Oxygen detection sensor; 8. Infrared spectrum sensor; 9. Hydrogen sulfide detection sensor; 10. Controller; 11. Transmission tube; 12. Pressure sensor; 13. Vanadium-tungsten-titanium catalyst layer; 14. Zeolite molecular sieve layer; 15. Hastelloy tube; 16. Ceramic tube. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0033] Next, the present invention is described in detail with reference to schematic diagrams. For ease of illustration, when describing embodiments of the present invention, cross-sectional views illustrating device structures may be partially enlarged and not to scale. Furthermore, these schematic diagrams are merely illustrative and should not limit the scope of protection of the present invention. Furthermore, in actual production, three-dimensional dimensions, including length, width, and depth, should be included.

[0034] Furthermore, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0035] See also Figures 1 to 6 The present invention provides a technical solution: a boiler combustion atmosphere monitoring device, comprising a base 1, a filter 2, a heater 3 and a controller 10 are provided at the upper end of the base 1, a sampling component 4 is provided at the input end of the filter 2; the sampling component 4 includes an air compressor 42 and three venturi tubes 41 connected thereto, the input ends of the three venturi tubes 41 are respectively provided with a stainless steel tube 5, a Hastelloy tube 15 and a ceramic tube 16 for connecting to different positions of the boiler; the filter 2 is connected to the heater 3, and three detection tubes 6 are provided at the output end of the heater 3, each detection tube 6 is provided with an oxygen detection sensor 7, an infrared spectrum sensor 8 and a hydrogen sulfide detection sensor 9.

[0036] refer to Figure 1 、 Figure 3 and Figure 4 An air compressor 42 is fixed to one side of the filter 2 via a bracket. A conduit 43 is connected to the output end of the air compressor 42. An instrument air duct 44 is connected between one side of the conduit 43 and the upper end of the venturi tube 41. A flow sensor 45 is installed within the instrument air duct 44. One end of each venturi tube 41 is connected to the stainless steel tube 5, the Hastelloy alloy tube 15, and the ceramic tube 16, in sequence, via a flange. Pressure sensors 12 are installed within each of these tubes.

[0037] It should be noted that the power is provided by an air compressor 42 and an instrument air duct 44, which are generally readily available at large boiler sites. While effectively guiding the flow through the venturi tube 41, it also avoids the various problems of unstable gas flow affecting detection caused by natural diffusion or pump suction methods used in traditional detection methods.

[0038] A flow sensor 45 is provided in the instrument air duct 44, and a pressure sensor 12 is provided in each sampling tube to monitor the fluid parameters in real time during the sampling process. Combined with the algorithm compensation of the controller 10, the influence of weather (air pressure, temperature) fluctuations on O2 measurement is eliminated. A flow sensor 45 is provided in the instrument air duct 44, and a pressure sensor 12 is provided in each sampling tube to collect the compressed air flow in the instrument air duct 44 and the flue gas pressure data in the sampling tube in real time and transmit them to the controller 10. The controller 10 uses a preset algorithm to analyze the degree to which the parameters deviate from the ideal value to achieve compensation. Specifically, when the flow sensor 45 detects that the compressed air flow in the instrument air duct 44 is lower than the set value, it indicates that the negative pressure generated by the venturi tube 41 is insufficient, which may cause the flue gas sampling volume to be reduced or unstable. The controller 10 calculates the output power of the air compressor 42 that needs to be increased through the algorithm, and sends a command to increase its speed, thereby increasing the compressed air flow and ensuring stable air extraction from the venturi tube 41.

[0039] If the flow rate is too high, the algorithm will control the reduction of output power to avoid energy waste and impact on the system. For the pressure sensor 12, when it detects abnormal fluctuations in the flue gas pressure in the sampling tube (such as sudden changes in boiler load or changes in weather pressure causing a sudden increase or decrease in pressure), the algorithm will conduct a comprehensive analysis based on the pressure change amplitude and flow data. If the pressure is too high and may block the sampling tube, the controller 10 will instruct the air compressor 42 to increase the pressure appropriately, or control the valve to adjust the sampling path; if the pressure is too low and there may be a leak, the algorithm will trigger an alarm and start the emergency shutdown procedure. Usually, the compressed air flow in the instrument air duct 44 should be controlled at 5-15m 3 / h, ensuring that the venturi tube 41 generates a stable negative pressure (generally in the negative pressure range of -20kPa to -5kPa) to extract the flue gas; the normal fluctuation range of the flue gas pressure in each sampling tube is around ±10% of the atmospheric pressure. Specifically, it is necessary to perform dynamic compensation and adjustment through the algorithm of the controller 10 according to the actual operating conditions of the boiler and the pipeline resistance characteristics to ensure the accuracy and stability of the flue gas sampling and avoid deviations in the detection data due to abnormal flow and pressure.

[0040] The venturi tube 41 and the air compressor 42 cooperate to form an adjustable negative pressure exhaust system, which automatically adjusts the sampling volume according to the boiler load. At the same time, the controller 10 correlates the O2 data with other parameters (such as NOx concentration and H2S content) to reduce the risk of misjudging a single O2 value due to changes in the type of coal burned. It should be noted that in order to prevent the flue gas from flowing back from the venturi tube 41 into the air compressor 42: a one-way flow structure design can be adopted, and a one-way valve can be installed at one end of the instrument air duct 44 close to the air compressor 42 or at the compressed air inlet of the venturi tube 41. The one-way valve only allows compressed air to flow from the air compressor 42 to the venturi tube 41. When the system pressure fluctuates or shuts down, the one-way valve automatically closes to prevent the flue gas from flowing back.

[0041] refer to Figure 1 Three transmission tubes 11 are provided between the output end of filter 2 and the input end of heater 3. These tubes 11 are connected to the stainless steel tube 5, the Hastelloy alloy tube 15, and the ceramic tube 16 in sequence through filter 2. One end of each of the stainless steel tube 5, the Hastelloy alloy tube 15, and the ceramic tube 16 is connected to the three detection tubes 6 in sequence through filter 2 and heater 3, allowing independent gas transportation at each different location in the boiler.

[0042] refer to Figure 6 Each detection tube 6 is provided with a vanadium-tungsten-titanium catalyst layer 13 and a zeolite molecular sieve layer 14. Both the vanadium-tungsten-titanium catalyst layer 13 and the zeolite molecular sieve layer 14 are honeycomb-shaped. The vanadium-tungsten-titanium catalyst layer 13 is located at the left end of the zeolite molecular sieve layer 14.

[0043] It should be noted that the main function of the vanadium tungsten titanium catalyst layer 13 is to efficiently convert nitrogen oxides (NOx) in the flue gas into nitrogen and water through a catalytic reduction reaction in the high temperature range of 280-420°C using ammonia or urea as a reducing agent. It is the core functional layer for removing NOx; the zeolite molecular sieve layer 14 has the dual functions of low-temperature catalytic reduction (180-300°C) and adsorption and storage of NOx. On the one hand, it can use acidic sites to adsorb NH3 and react with NOx at low temperatures; on the other hand, it can store NOx under oxygen-rich conditions and release it for reduction when the operating conditions change, thereby compensating for the high-temperature limitations of vanadium tungsten titanium and improving the denitrification efficiency in the entire temperature range;

[0044] The thickness of the two is usually designed according to actual needs. The thickness of the vanadium-tungsten-titanium catalyst layer 13 is generally 3-5 mm, ensuring sufficient active sites without excessively increasing airflow resistance; the thickness of the zeolite molecular sieve layer 14 is 2-4 mm, taking into account both adsorption capacity and rapid mass transfer performance.

[0045] In terms of the fixing method to the inner wall of the detection tube 6, a high-temperature resistant adhesive (such as alumina-based ceramic glue) is commonly used to directly stick the honeycomb catalytic layer and molecular sieve layer to the inner wall of the detection tube to ensure a tight bond without affecting the gas circulation; a frame made of metal or ceramic material can also be designed, and the catalytic layer and molecular sieve layer can be embedded in the frame, and then fixed to the inside of the detection tube 6 by welding or bolting. This method is easy to disassemble and replace, and is suitable for scenarios that require regular maintenance.

[0046] The vanadium-tungsten-titanium catalyst layer 113 and the zeolite molecular sieve layer 14 are designed in a honeycomb shape, mainly based on multiple considerations such as mass transfer efficiency, fluid mechanics, mechanical properties, and engineering practicality. The specific reasons are as follows:

[0047] Maximizing contact area: The honeycomb structure is composed of a large number of regularly arranged parallel microporous channels, providing an extremely high specific surface area per unit volume (typically 300-800m2 / m3). Taking the vanadium-tungsten-titanium catalyst layer 13 as an example, more surface area means more active sites for contact with nitrogen oxides (NOx) in the flue gas, accelerating the catalytic reduction reaction. The zeolite molecular sieve layer 14 utilizes the large surface area of ​​the honeycomb structure to enhance the adsorption capacity of ammonia (NH3) and NOx, improving reaction efficiency at low temperatures.

[0048] Optimized airflow distribution: The regular pore structure makes the flue gas flow rate more uniform within the detection tube, avoiding turbulence or dead corners. This ensures that the flue gas can pass through the catalytic layer and molecular sieve layer at a stable speed and direction. All gas molecules have similar reaction time, preventing local underreaction or overreaction, and improving the overall treatment effect.

[0049] Reduced fluid resistance: Compared to granular or other irregular structures, the honeycomb's linear or slightly expanded channels significantly reduce frictional resistance during gas flow. This significantly reduces system energy consumption in high-flow flue gas treatment scenarios (such as industrial boilers), eliminating the need for additional power equipment to overcome resistance and meeting engineering energy conservation requirements.

[0050] Anti-clogging and easy maintenance: The rigid, monolithic honeycomb structure is resistant to breakage, and the smooth pore walls reduce the potential for dust and particulate matter to settle. Even small amounts of dust can be easily removed through sonic purging or pulse cleaning, making maintenance much easier and more cost-effective than for loosely accumulated particulate materials.

[0051] Electrical introduction: The flow sensor 45 can use the SITRANSFMMAG6000 electromagnetic flowmeter, which is suitable for measuring the flow of conductive liquids with high accuracy and good stability. The pressure sensor 12 can use the CYB1300 diffused silicon pressure transmitter, which can convert the pressure signal into a standard electrical signal and has strong anti-interference ability. The oxygen detection sensor 7 can use the GPR-25 oxygen sensor, which is based on electrochemical principles and has a fast response speed and is suitable for oxygen concentration detection. The infrared spectrum sensor 8 can use the MIR900 infrared gas analyzer, which detects gas components through infrared spectroscopy technology and has a wide measurement range. The hydrogen sulfide detection sensor 9 can use the H2S-A1 electrochemical hydrogen sulfide sensor, which is sensitive to hydrogen sulfide gas and has high detection accuracy. The controller 10 can use the Siemens S7-1200PLC, which is powerful and reliable and suitable for industrial automation control scenarios.

[0052] Heater 3 can use the OMRONE5ZN series intelligent PID temperature-controlled electric heater, which can accurately control the heating temperature and has multiple temperature control modes to adapt to the temperature regulation requirements required for flue gas treatment; filter 2 can use a 3MFFU fan filter unit with a built-in high-efficiency HEPA filter, which has high efficiency in filtering particulate impurities in the flue gas and low wind resistance, which can effectively ensure the flue gas pretreatment effect.

[0053] Working principle: The air compressor 42 delivers compressed air to the three venturi tubes 41 through the conduit 43 and the instrument air duct 44, so that the venturi tubes 41 generate negative pressure, thereby extracting flue gas from different positions of the boiler through the stainless steel tube 5, the Hastelloy tube 15 and the ceramic tube 16;

[0054] After the flue gas passes through filter 2 to remove impurities, it is heated to a suitable temperature by heater 3 to prevent water vapor condensation from affecting detection accuracy. The heated flue gas enters detection tube 6, where oxygen detection sensor 7, infrared spectrum sensor 8, and hydrogen sulfide detection sensor 9 respectively perform real-time detection of the concentrations of oxygen, various nitrogen oxides, and hydrogen sulfide in the flue gas. Controller 10 receives data from each sensor and, based on a built-in card-edge control algorithm, comprehensively analyzes information on multiple parameters such as oxygen, nitrogen oxides, and hydrogen sulfide to automatically adjust the boiler's air intake and fuel supply, achieving precise control of the boiler's combustion process.

[0055] At the same time, the honeycomb vanadium-tungsten-titanium catalytic layer 13 and the zeolite molecular sieve layer 14 in the detection tube 6 catalytically decompose the pollutants in the flue gas, and assist in calculating the pollutant conversion rate by comparing the sensor data before and after catalysis.

[0056] It will be appreciated that in the development of any actual embodiment, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will, for those of ordinary skill having the benefit of this disclosure, be a routine undertaking of design, fabrication, and production without undue experimentation.

[0057] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A boiler combustion atmosphere monitoring device, comprising a base (1), characterized in that: The upper end of the base (1) is provided with a filter (2), a heater (3) and a controller (10), and the input end of the filter (2) is provided with a sampling component (4); The sampling component (4) includes an air compressor (42) and three venturi tubes (41) connected thereto, wherein the input ends of the three venturi tubes (41) are respectively provided with a stainless steel tube (5), a Hastelloy tube (15) and a ceramic tube (16) for connecting to different positions of the boiler; The filter (2) is connected to the heater (3), and three detection tubes (6) are provided at the output end of the heater (3). Each of the detection tubes (6) is provided with an oxygen detection sensor (7), an infrared spectrum sensor (8) and a hydrogen sulfide detection sensor (9).

2. A boiler combustion atmosphere monitoring device according to claim 1, characterized in that: An air compressor (42) is fixed to one side of the filter (2) via a bracket, an output end of the air compressor (42) is connected to a conduit (43), and an instrument air duct (44) is connected between one side of the conduit (43) and the upper end of the venturi tube (41).

3. A boiler combustion atmosphere monitoring device according to claim 2, characterized in that: A flow sensor (45) is provided in the instrument air duct (44).

4. A boiler combustion atmosphere monitoring device according to claim 2, characterized in that: One end of each of the venturi tubes (41) is connected to the stainless steel tube (5), the Hastelloy tube (15) and the ceramic tube (16) in sequence through a flange.

5. The boiler combustion atmosphere monitoring device according to claim 4, characterized in that: Pressure sensors (12) are provided in the stainless steel tube (5), the Hastelloy tube (15) and the ceramic tube (16).

6. The boiler combustion atmosphere monitoring device according to claim 1, characterized in that: Three transmission tubes (11) are provided between the output end of the filter (2) and the input end of the heater (3), and the three transmission tubes (11) are sequentially connected to the stainless steel tube (5), the Hastelloy tube (15) and the ceramic tube (16) through the filter (2).

7. The boiler combustion atmosphere monitoring device according to claim 4, characterized in that: One end of the stainless steel tube (5), the Hastelloy alloy tube (15) and the ceramic tube (16) is connected to the three detection tubes (6) in sequence through the filter (2) and the heater (3).

8. The boiler combustion atmosphere monitoring device according to claim 7, characterized in that: Each detection tube (6) is provided with a vanadium-tungsten-titanium catalytic layer (13) and a zeolite molecular sieve layer (14), and both the vanadium-tungsten-titanium catalytic layer (13) and the zeolite molecular sieve layer (14) are honeycomb-shaped.

9. The boiler combustion atmosphere monitoring device according to claim 8, characterized in that: The vanadium, tungsten and titanium catalyst layer (13) is located at the left end of the zeolite molecular sieve layer (14).

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