A device and method for measuring ammonia concentration in flue gas in a denitration device

Abstract

The present invention discloses a device and method for measuring the ammonia concentration in the flue gas in a denitrification device. First, a sampling tube device is configured as a connecting device for receiving flue gas on site or in a laboratory of a thermal power plant. The sampling tube section is equipped with filter cotton for filtering impurities in the flue gas. Then the flue gas is separated into steam and water through a flue gas filter and filtered before entering an ammonia-sensitive electrode testing device to measure and analyze the incoming flue gas. At the same time, the remaining flue gas flows through a flue gas sampling pump and a flue gas exhaust treatment device in sequence, and the treated exhaust gas is discharged. The flue gas sampling pump is provided with a frequency conversion device, which can actively and in real time adjust the output of the sampling pump through the set flow rate and differential pressure to stabilize the flow rate of the extracted flue gas. The present invention avoids the problems of inaccurate and untimely measurement of ammonia concentration by chemical methods, laser methods, etc., and the problems of excessive ammonia spraying in engineering applications causing ammonia to react with sulfur trioxide to generate ammonium bisulfate and block downstream equipment.

Description

Technical Field

[0001] The invention relates to a device and a method for measuring the ammonia concentration in flue gas in a denitration device. Background Art

[0002] At present, the domestic environmental protection situation is severe, and flue gas environmental protection standards have been proposed for large coal-fired power plants and chemical energy industries. Flue gas denitrification in thermal power plants is a very mature technology that has been used for many years. At present, most of the denitrification routes are selective catalytic reduction (SCR) denitrification technology, but the application of this technology in thermal power plants is also inevitably There are some technical deficiencies, such as the reducing agent ammonia used in denitrification will react with sulfur trioxide in the flue gas to generate ammonium bisulfate, blocking downstream equipment such as air preheaters, and adversely affecting the denitrification catalyst. Controlling the ammonia content in the flue gas and spraying ammonia reasonably is one of the fundamental ways to solve this problem. For complex and changeable working conditions on site, it becomes particularly important to quickly and accurately measure the ammonia concentration at each point in the SCR area. Summary of the invention

[0003] The purpose of the present invention is to overcome the various problems existing in the prior art of inaccurate and untimely measurement of ammonia concentration, and the situation in which excessive ammonia spraying in engineering applications causes ammonia to react with sulfur trioxide to generate ammonium bisulfate, which blocks downstream equipment, and to provide a device and method for measuring the ammonia concentration in flue gas in a denitrification device.

[0004] The technical solution adopted by the present invention to solve the above-mentioned problem is: a device for measuring the ammonia concentration in the flue gas in the denitrification device, characterized in that it includes a sampling tube device and an ammonia concentration testing device; the sampling tube device includes a sampling head with a thermocouple, a primary tube section with filter cotton, a diode section with filter cotton, a triode section with filter cotton, a quadruple tube section with filter cotton and a first connecting block, and the sampling head, the primary tube section, the diode section, the triode section, the quadruple tube section and the first connecting block are connected in sequence; the ammonia concentration testing device includes a second connecting block, a flue gas The filter, ammonia-sensitive electrode test device, a flue gas sampling pump, a flue gas exhaust treatment device, a controller and an integrated control display, the second connection block, the flue gas filter, the ammonia-sensitive electrode test device, the flue gas sampling pump and the flue gas exhaust treatment device are connected in sequence through a flue gas duct with a heating pipe and a thermocouple, the flue gas filter, the ammonia-sensitive electrode test device, the flue gas sampling pump and the flue gas exhaust treatment device are all placed on a fixing device, the integrated control display, the ammonia-sensitive electrode test device and the flue gas sampling pump are all connected to the controller; the first connection block is connected to the second connection block.

[0005] Furthermore, the sampling tube device is a structure in which the length of the tube section can be extended, and the primary tube section, the diode section, the triode section and the quaternary tube section are all sealed structures to prevent the internal smoke from leaking out. The sampling tube device is provided with a sampling head with a thermocouple, and the smoke enters the sampling tube device from there. The sampling head position is designed with a thermocouple for measuring the smoke temperature. The filter cotton of each tube section can filter impurities in the smoke.

[0006] Furthermore, the smoke filter can filter smoke with a small amount of particulate matter into smoke without particulate matter to prevent pollution of subsequent equipment, and can achieve steam-water separation, filter out moisture in the smoke, and allow dry smoke to flow through.

[0007] Furthermore, the smoke sampling pump is used to provide power for extracting smoke, and the smoke sampling pump is equipped with a frequency converter to facilitate real-time adjustment of the output of the smoke sampling pump to ensure uniform and stable smoke flow.

[0008] Furthermore, the flue gas exhaust treatment device can process the remaining flue gas flowing through the ammonia sensitive electrode testing device into clean flue gas and discharge it to the outside of the ammonia concentration testing device.

[0009] Furthermore, by issuing instructions on the integrated control display, the controller transmits them to the ammonia-sensitive electrode testing device and the flue gas sampling pump to control the start and stop of the ammonia-sensitive electrode testing device and the flue gas sampling pump; the thermocouple on the sampling head is transmitted to the integrated control display through the controller, and instructions are issued on the integrated control display to control the temperature in the flue gas duct through which the flue gas flows to be consistent with the temperature at the sampling head.

[0010] The working method of the device for measuring the ammonia concentration in the flue gas in the denitrification device is characterized in that the process is as follows: first, the preheating temperature of the ammonia concentration test device is set through the integrated control display, and the flue gas pipeline is heated. When the temperature reaches the set value, the sampling tube device is inserted into the flue and the length is adjusted as needed; then the flow rate of flue gas extraction is set on the integrated control display, and the start sampling is clicked. The flue gas sampling pump with a frequency converter is started through the controller control. After the flue gas enters the ammonia concentration test device and is filtered through the flue gas filter for steam-water separation, the dry flue gas flows into the ammonia sensitive electrode test device, and the ammonia sensitive electrode test device automatically extracts An appropriate amount of flue gas is measured and analyzed, and the measured value is transmitted to the integrated control display through the controller. The flue gas after passing through the ammonia sensitive electrode test device flows through the flue gas sampling pump and the flue gas exhaust treatment device in turn, and is discharged to the outside of the ammonia concentration test device after exhaust treatment; the ammonia concentration test device is preheated before use by heating the flue gas duct, and the temperature is adjusted in real time through the feedback of the thermocouple on the sampling head to ensure that the flue gas temperature in the flue gas duct is consistent with the on-site conditions; the output of the flue gas sampling pump is intelligently adjusted by the frequency converter to ensure the stability of the extracted flue gas flow rate; after completing the measurement, click the stop button on the integrated control display to stop working.

[0011] Compared with the prior art, the present invention has the following advantages and effects: first, a flue gas sampling pump with a frequency converter is configured. When used in the flue of a power plant, it is generally in a negative pressure state, so a certain suction force is required. The sampling pump provides a stable suction force for collecting flue gas to ensure a stable flue gas flow rate. The sampling tube device is in direct contact with the on-site flue. It has a sampling head with a thermocouple. The flue gas enters from the sampling head. The thermocouple can measure the temperature of the flue gas in the flue. The sampling tube is divided into four sections, which can be retracted and applied to the wide flue on site. Each section is provided with its own filter cotton to filter impurities in the flue gas. Secondly, the flue gas enters the ammonia concentration test device through the sampling tube device. The device is still provided with a filter device for steam-water separation to filter out all impurities and moisture, ensuring that the flue gas entering the ammonia-sensitive electrode test device is clean and dry flue gas. Compared with the traditional chemical method and laser method, the ammonia-sensitive electrode method measures ammonia concentration accurately and quickly. The remaining flue gas is treated by the flue gas exhaust treatment device and then discharged.

[0012] The present invention avoids the problems of inaccurate and untimely measurement of ammonia concentration by chemical methods, laser methods, etc., as well as excessive ammonia spraying in engineering applications, which causes ammonia to react with sulfur trioxide to generate ammonium bisulfate, which blocks downstream equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic diagram of the structure of the sampling tube device in the embodiment of the present invention.

[0014] Figure 2 Schematic diagram of the structure of the ammonia concentration testing device in the embodiment of the present invention.

[0015] In the figure: sampling head 1, primary tube section 2, diode section 3, triode section 4, quaternary tube section 5, first connecting block 6, sampling tube device 7, second connecting block 8, flue gas filter 9, ammonia sensitive electrode testing device 10, flue gas sampling pump 11, flue gas exhaust treatment device 12, controller 13, integrated control display 14, flue gas duct 15, ammonia concentration testing device 16, fixing device 17. DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and by way of examples. The following examples are intended to explain the present invention but the present invention is not limited to the following examples.

[0017] Example

[0018] See also Figure 1 to Figure 2In this embodiment, a device for measuring the ammonia concentration in the flue gas in the denitrification device includes a sampling tube device 7 and an ammonia concentration test device 16; the sampling tube device 7 includes a sampling head 1 with a thermocouple, a primary tube section 2 with filter cotton, a diode section 3 with filter cotton, a triode section 4 with filter cotton, a quadruple tube section 5 with filter cotton and a first connecting block 6, and the sampling head 1, the primary tube section 2, the diode section 3, the triode section 4, the quadruple tube section 5 and the first connecting block 6 are connected in sequence; the ammonia concentration test device 16 includes a second connecting block 8, a flue gas filter 9, an ammonia sensitive electrode test device 10, a flue gas filter 9, a The sampling pump 11, the flue gas exhaust treatment device 12, the controller 13 and the integrated control display 14, the second connecting block 8, the flue gas filter 9, the ammonia-sensitive electrode test device 10, the flue gas sampling pump 11 and the flue gas exhaust treatment device 12 are connected in sequence through a flue gas duct 15 with a heating pipe and a thermocouple, the flue gas filter 9, the ammonia-sensitive electrode test device 10, the flue gas sampling pump 11 and the flue gas exhaust treatment device 12 are all placed on a fixing device 17, the integrated control display 14, the ammonia-sensitive electrode test device 10 and the flue gas sampling pump 11 are all connected to the controller 13; the first connecting block 6 is connected to the second connecting block 8.

[0019] In this embodiment, the sampling tube device 7 is a structure in which the length of the tube section can be extended, and the primary tube section 2, the diode section 3, the triode section 4 and the quaternary tube section 5 are all sealed structures to prevent the internal smoke from leaking out. The sampling tube device 7 is provided with a sampling head 1 with a thermocouple, and the smoke enters the sampling tube device 7 from there. The sampling head position is designed with a thermocouple for measuring the smoke temperature. The filter cotton of each tube section can filter impurities in the smoke.

[0020] In this embodiment, the smoke filter 9 can filter smoke with a small amount of particulate matter into smoke without particulate matter to prevent pollution of subsequent equipment, and can also achieve steam-water separation, filter out moisture in the smoke, and allow dry smoke to flow through.

[0021] In this embodiment, the smoke sampling pump 11 is used to provide power for extracting smoke, and the smoke sampling pump 11 is configured with a frequency converter to facilitate real-time adjustment of the output of the smoke sampling pump 11 to ensure uniform and stable smoke flow.

[0022] In this embodiment, the flue gas exhaust treatment device 12 can process the remaining flue gas flowing through the ammonia sensitive electrode testing device 10 into clean flue gas and discharge it to the outside of the ammonia concentration testing device 16.

[0023] In this embodiment, by issuing instructions on the integrated control display 14, the controller 13 transmits them to the ammonia-sensitive electrode test device 10 and the smoke sampling pump 11, and controls the start and stop of the ammonia-sensitive electrode test device 10 and the smoke sampling pump 11; the thermocouple on the sampling head 1 is transmitted to the integrated control display 14 through the controller 13, and an instruction is issued on the integrated control display 14 to control the temperature in the smoke duct 15 through which the smoke flows to be consistent with the temperature at the sampling head 1. The controller 13 can be a PLC controller.

[0024] Working method: First, set the preheating temperature of the ammonia concentration test device 16 through the integrated control display 14, and heat the flue gas duct 15. When the temperature reaches the set value, insert the sampling tube device 7 into the flue and adjust the length as needed; then set the flow rate of flue gas extraction on the integrated control display 14, click to start sampling, and start the flue gas sampling pump 11 with a frequency converter through the controller 13. The flue gas enters the ammonia concentration test device 16 and passes through the flue gas filter 9 for steam-water separation filtration. The dry flue gas flows into the ammonia sensitive electrode test device 10, and the ammonia sensitive electrode test device 10 automatically extracts an appropriate amount of flue gas for measurement and analysis and sends the measured value The data is transmitted to the integrated control display 14 through the controller 13. The flue gas after passing through the ammonia sensitive electrode test device 10 flows through the flue gas sampling pump 11 and the flue gas exhaust treatment device 12 in turn, and is discharged to the outside of the ammonia concentration test device 16 after exhaust treatment; the ammonia concentration test device 16 is preheated by heating the flue gas duct 15 before use, and the temperature is adjusted in real time through the feedback of the thermocouple on the sampling head 1 to ensure that the flue gas temperature in the flue gas duct 15 is consistent with the on-site conditions; the output of the flue gas sampling pump 11 is intelligently adjusted by the frequency converter to ensure the stability of the extracted flue gas flow rate; after the measurement is completed, click the stop button on the integrated control display 14 to stop working.

[0025] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0026] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the protection scope of the present invention. Any changes and modifications made by any technician familiar with the technology without departing from the concept and scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A method for measuring the ammonia concentration in flue gas of a denitrification device, characterized in that: The device for measuring the ammonia concentration in the flue gas in the denitrification device comprises a sampling tube device (7) and an ammonia concentration test device (16); the sampling tube device (7) comprises a sampling head (1) with a thermocouple, a primary tube section (2) with a filter cotton, a diode section (3) with a filter cotton, a triode section (4) with a filter cotton, a quaternary tube section (5) with a filter cotton and a first connecting block (6); the sampling head (1), the primary tube section (2), the diode section (3), the triode section (4), the quaternary tube section (5) and the first connecting block (6) are connected in sequence; the ammonia concentration test device (16) comprises a second connecting block (8), a flue gas filter (9), an ammonia sensitive electrode test device (10), a flue gas sampling pump (11), a flue gas exhaust treatment device (12), a controller (13) and an integrated control display (1 4), the second connection block (8), the flue gas filter (9), the ammonia-sensitive electrode test device (10), the flue gas sampling pump (11) and the flue gas exhaust treatment device (12) are connected in sequence through a flue gas pipeline (15) with a heating pipe and a thermocouple, the flue gas filter (9), the ammonia-sensitive electrode test device (10), the flue gas sampling pump (11) and the flue gas exhaust treatment device (12) are all placed on a fixing device (17), and the integrated control display (14), the ammonia-sensitive electrode test device (10) and the flue gas sampling pump (11) are all connected to a controller (13); the first connection block (6) is connected to the second connection block (8); the sampling pipe device (7) is a structure in which the length of its pipe section can be extended, and the first pipe section (2), the diode section (3), the triode section (4) and the fourth pipe section (5) are all sealed structures; The working method is as follows: first, the preheating temperature of the ammonia concentration test device (16) is set through the integrated control display (14), and the flue gas duct (15) is heated. When the temperature reaches the set value, the sampling tube device (7) is inserted into the flue and the length is adjusted as needed; then, the flow rate of flue gas extraction is set on the integrated control display (14), and a click is made to start sampling. The controller (13) controls the start of the flue gas sampling pump (11) with a frequency converter, and the flue gas enters the ammonia concentration test device (16) and passes through the flue gas filter (9) for steam-water separation filtration. The dry flue gas then flows into the ammonia sensitive electrode test device (10), and the ammonia sensitive electrode test device (10) automatically extracts an appropriate amount of flue gas for measurement and analysis and transmits the measured data to the ammonia sensitive electrode test device (10). The value is transmitted to the integrated control display (14) through the controller (13), and the flue gas after passing through the ammonia sensitive electrode test device (10) flows through the flue gas sampling pump (11) and the flue gas exhaust treatment device (12) in sequence, and is discharged to the outside of the ammonia concentration test device (16) after exhaust treatment; the ammonia concentration test device (16) is preheated by heating the flue gas duct (15) before use, and the temperature is adjusted in real time through the feedback of the thermocouple on the sampling head (1) to ensure that the flue gas temperature in the flue gas duct (15) is consistent with the on-site conditions; the output of the flue gas sampling pump (11) is intelligently adjusted by the frequency converter to ensure that the extracted flue gas flow rate is stable; after the measurement is completed, click the stop button on the integrated control display (14) to stop working.

2. The working method of the device for measuring the ammonia concentration in the flue gas in the denitrification device according to claim 1 is characterized in that: The smoke filter (9) filters smoke with a small amount of particulate matter into smoke without particulate matter to prevent pollution of subsequent equipment, and realizes steam-water separation, filters out water in the smoke, and allows dry smoke to flow through.

3. The working method of the device for measuring the ammonia concentration in the flue gas in the denitrification device according to claim 1 is characterized in that: The smoke sampling pump (11) is used to provide power for extracting smoke, and the smoke sampling pump (11) is equipped with a frequency converter.

4. The working method of the device for measuring the ammonia concentration in the flue gas in the denitrification device according to claim 1 is characterized in that: The flue gas exhaust treatment device (12) treats the remaining flue gas flowing through the ammonia-sensitive electrode testing device (10) into clean flue gas and discharges the clean flue gas to the outside of the ammonia concentration testing device (16).

5. The working method of the device for measuring the ammonia concentration in the flue gas in the denitration device according to claim 1 is characterized in that: By issuing instructions on the integrated control display (14), the controller (13) transmits the instructions to the ammonia-sensitive electrode test device (10) and the smoke sampling pump (11), thereby controlling the start and stop of the ammonia-sensitive electrode test device (10) and the smoke sampling pump (11); the thermocouple on the sampling head (1) is transmitted to the integrated control display (14) through the controller (13), and an instruction is issued on the integrated control display (14), thereby controlling the temperature in the smoke duct (15) through which the smoke flows to be consistent with the temperature at the sampling head (1).

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