Denitration multi-point monitoring device for coal-fired power plant

Abstract

The utility model discloses a coal-fired power plant denitration multi-point monitoring device which comprises a plurality of sampling transmission units, a calibration pipeline unit, a sample pipeline processing unit and an analysis pipeline unit which are arranged on a coal-fired power plant denitration device. The calibration pipeline unit adjusts the dew point of flue gas to be consistent with the dew point of standard gas, and the sample pipeline treatment unit is used for cooling, dewatering and filtering the flue gas from the calibration pipeline unit and transmitting the flue gas to the analysis pipeline unit to analyze the concentration of nitrogen oxide and oxygen in the flue gas. According to the multi-point monitoring device for denitration of the coal-fired power plant, complete extraction type flue gas monitoring is adopted, nitric oxide and oxygen concentration of flue gas in each partition of a denitration device can be measured in real time, and changes of the nitric oxide and the oxygen concentration caused by changes of a flow field are monitored in real time.

Description

Technical Field

[0001] This utility model relates to the field of denitrification multi-point monitoring technology, specifically, to a denitrification multi-point monitoring device for coal-fired power plants. Background Technology

[0002] Currently, while meeting environmental protection requirements, the economic efficiency of denitrification technology is also an indispensable factor in the development of flue gas denitrification systems for coal-fired power plants. Enterprises need to minimize operating costs while ensuring denitrification efficiency, achieving a win-win situation for both economic and environmental benefits.

[0003] Traditional ammonia distribution methods assume that flue gas flow and nitrogen oxide distribution are constant. In reality, these parameters will change with changes in boiler load or combustion mode. Most single-point monitoring of denitrification can only represent the nitrogen oxide concentration at that point and cannot accurately reflect the nitrogen oxide distribution of the entire flue section. Furthermore, it cannot guide the dynamic distribution and adjustment of the ammonia injection grid, which may lead to local over-injection or under-injection of ammonia.

[0004] The existing multi-point denitrification monitoring system uses three sampling probes and a set of pretreatment sampling methods. This method has certain problems: First, due to the inconsistent resistance of the three sampling probes and the pressure difference inside the flue, it is difficult to adjust the flue gas mixing ratio of the three sampling probes, resulting in low representativeness of the measurement and failure to meet the expected requirements. Second, relying on a single sampling pump for sampling, when checking the gas path sealing, the three sampling probes must be checked one by one to confirm the leak point, which is very unfavorable for later maintenance, and thus leads to a high failure rate of the multi-point denitrification monitoring system.

[0005] In order to solve the above-mentioned problem of flue gas mixing uniformity, three independent pretreatment units are adopted, namely, three sampling pumps sampling at the same time, the treated flue gas is fully mixed through a low-temperature flue gas mixer, and then the mixed flue gas is sent to an analyzer for analysis. The main advantage of this method is that the flue gas mixing ratio can be adjusted in any proportion by adjusting the flow rate of the float flow meter; the three sampling channels are independent of each other, which is convenient for daily maintenance. By sampling the three probes separately, online distribution tests can be carried out. However, the following defects still exist: (1) The load of a thermal power plant is generally variable. Measuring the mixing value of the three zones cannot guarantee the uniformity of ammonia injection. There will still be local excessive ammonia injection, which will cause blockage of subsequent process units; (2) The denitrification multi-point monitoring system involves multiple pretreatment units, and the maintenance workload is large. Utility Model Content

[0006] To address the problems existing in the prior art, this utility model provides a multi-point monitoring device for denitrification in coal-fired power plants. The device reduces its size by using a multi-channel integrated condenser in the sample pipeline processing unit, and monitors and warns of multi-point sampling pipelines through an early warning unit to avoid blockage and facilitate maintenance.

[0007] To achieve the above technical objectives, this utility model adopts the following technical solution: a multi-point monitoring device for denitrification in a coal-fired power plant, comprising: several sampling and transmission units, a calibration pipeline unit, a sample pipeline processing unit, and an analysis pipeline unit installed on the denitrification device of the coal-fired power plant. The sampling and transmission units transmit the sampled flue gas to the calibration pipeline unit, the calibration pipeline unit adjusts the dew point of the flue gas to be consistent with the dew point of the calibration gas, and the sample pipeline processing unit is used to cool, dehydrate, and filter the flue gas from the calibration pipeline unit, and transmit it to the analysis pipeline unit to analyze the concentration of nitrogen oxides and oxygen in the flue gas.

[0008] Furthermore, the sampling transmission unit includes: a sampling probe rod, a sampling probe, and a transmission pipeline. One end of the sampling probe is connected to one end of the sampling probe rod, and the other end of the sampling probe rod extends into the denitrification device of the coal-fired power plant through a flange sleeve installed on the denitrification device of the coal-fired power plant. The other end of the sampling probe is connected to one end of the transmission pipeline, and the other end of the transmission pipeline is connected to a calibration pipeline unit.

[0009] Furthermore, the flange sleeve is provided with an insulation sleeve, the sampling probe is a heatable probe, and the transmission pipeline is a heat tracing pipeline.

[0010] Furthermore, it also includes: a ceramic filter device, a backflush main pipe, backflush branch pipes, a first solenoid valve, and a compressor. The sampling probe is equipped with a ceramic filter device at its inlet. One end of the backflush main pipe is sealed, and the other end is connected to the air outlet of the compressor. The backflush main pipe is equipped with a first solenoid valve. Several backflush branch pipes are provided on the backflush main pipe located between the first solenoid valve and the sealed end. Each backflush branch pipe is connected to a ceramic filter device.

[0011] Furthermore, the calibration pipeline unit consists of a calibration gas pipeline and several first sample transfer pipelines. Each first sample transfer pipeline is connected to a transfer line, and a second solenoid valve is provided on the first sample transfer pipeline. A third solenoid valve is provided on the calibration gas pipeline. The calibration gas pipeline located at the normally closed end of the third solenoid valve is connected to calibration gas, and the calibration gas pipeline located at the normally open end of the third solenoid valve is connected to air. The calibration gas pipeline located at the common end of the third solenoid valve is provided with several calibration gas branch pipes, and each calibration gas branch pipe is connected to the corresponding first sample transfer pipeline through the normally closed end of the second solenoid valve.

[0012] Furthermore, the sample pipeline processing unit includes: a second sample transmission pipeline and an integrated condenser, an early warning unit, and a filter flow regulation unit disposed on the second sample transmission pipeline. The flue gas flowing out of the calibration pipeline unit enters the corresponding second sample transmission pipeline. The flue gas undergoes heat exchange and cooling through the integrated condenser. The cooled flue gas then flows through the early warning unit and then through the filter flow regulation unit.

[0013] Furthermore, the integrated condenser consists of several three-port direct-cooling heat exchange tubes, each of which cools one stream of flue gas. The upper end of each three-port direct-cooling heat exchange tube is provided with an inlet and an outlet, and the lower end is provided with a drain outlet. The flue gas entering the second sample transfer pipeline enters the three-port direct-cooling heat exchange tube through the inlet for heat exchange, and enters the second sample transfer pipeline side equipped with an early warning unit through the outlet. The drain outlet is connected to a peristaltic pump.

[0014] Furthermore, the early warning unit consists of several sensor groups, each of which is deployed on a second sample transfer pipeline. The sensor group consists of a pressure sensor and a dew point sensor.

[0015] Furthermore, each second sample transfer pipe is equipped with a filter flow regulating unit, which includes a sampling pump, a glass fiber filter, and a flow meter.

[0016] Furthermore, the analytical pipeline unit consists of several analytical pipelines, each of which is connected to a second sample transfer pipeline, and each analytical pipeline is equipped with a nitrogen oxide sensor and an oxygen sensor.

[0017] Compared with existing technologies, this utility model has the following advantages: The multi-point monitoring device for denitrification in coal-fired power plants adopts a fully extractive flue gas monitoring system, which can measure the nitrogen oxide and oxygen concentrations of flue gas in each zone of the denitrification device in real time, and monitor changes in nitrogen oxide and oxygen concentrations caused by changes in the flow field. Simultaneously, the sample pipeline processing unit in this utility model uses a multi-channel integrated condenser, which can condense and remove water from multiple flue gases, avoiding the space constraints caused by using multiple condensers separately, and reducing the heat dissipation problems and high costs associated with multiple condensers. The early warning unit in this utility model can simultaneously monitor the pressure and dew point of the flue gas transmission pipeline before entering the analysis pipeline unit. On-site maintenance personnel can take corresponding measures based on the real-time pressure and dew point conditions, reducing the workload of on-site problem investigation and improving work efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the denitrification multi-point monitoring device for coal-fired power plants according to this utility model;

[0019] Figure 2 This is a schematic diagram of the integrated condenser in this utility model;

[0020] Figure 3 This is a schematic diagram of the filter flow rate adjustment unit in this utility model;

[0021] The components are as follows: 1-Sampling and transmission unit, 2-Calibration pipeline unit, 3-Sample pipeline processing unit, 4-Analysis pipeline unit, 5-Integrated condenser, 6-Early warning unit, 7-Filter flow regulation unit, 8-Second sample transmission pipeline; 11-Sampling probe, 12-Sampling probe, 13-Transmission pipeline, 14-Ceramic filter device, 15-Backflush main pipe, 16-Backflush branch pipe, 17-Compressor; 21-Standard gas pipeline, 22-First sample transmission pipeline; 41-Nitrogen oxide sensor, 42-Oxygen sensor, 43-Analysis pipeline; 51-Three-port direct-cooling heat exchanger, 511-Inlet, 512-Outlet, 513-Drain, 514-Peristaltic pump; 61-Pressure sensor, 62-Dew point sensor; 71-Sampling pump, 72-Glass fiber filter device, 73-Flow meter. Detailed Implementation

[0022] The technical solution of this utility model will be further explained below with reference to the accompanying drawings.

[0023] like Figure 1 This is a schematic diagram of the structure of the multi-point monitoring device for denitrification in a coal-fired power plant according to this utility model. The device includes several sampling and transmission units 1, calibration pipeline units 2, sample pipeline processing units 3, and analysis pipeline units 4, all installed on the denitrification unit. The sampling and transmission units 1 transmit the sampled flue gas to the calibration pipeline units 2, which adjust the dew point of the flue gas to match that of the standard gas. The sample pipeline processing units 3 cool, dehydrate, and filter the flue gas from the calibration pipeline units 2 before transmitting it to the analysis pipeline units 4 to analyze the concentrations of nitrogen oxides and oxygen in the flue gas. This multi-point monitoring device for denitrification in a coal-fired power plant employs a fully extractive flue gas monitoring method, enabling real-time measurement of the nitrogen oxide and oxygen concentrations in the flue gas of each zone within the denitrification unit, and real-time monitoring of changes in nitrogen oxide and oxygen concentrations due to changes in the flow field.

[0024] In this utility model, the sampling transmission unit 1 includes: a sampling probe 11, a sampling probe 12, and a transmission pipeline 13. One end of the sampling probe 12 is connected to one end of the sampling probe 11, and the other end of the sampling probe 11 extends into the denitrification device of the coal-fired power plant through a flange sleeve installed on the denitrification device of the coal-fired power plant. The other end of the sampling probe 12 is connected to one end of the transmission pipeline 13, and the other end of the transmission pipeline 13 is connected to the calibration pipeline unit 2.

[0025] In one technical solution of this utility model, a heat-insulating sleeve is provided on the flange sleeve to prevent flue gas condensation from causing blockage of the sampling probe 11 when the flue gas exits the flange sleeve during the sampling process; similarly, in order to prevent flue gas from condensing on the sampling probe 12, the sampling probe 12 needs to be heated and kept warm. Therefore, a heatable probe is used, and the heating temperature of the heatable probe is adjustable from 0-250℃; the transmission pipeline 13 is a heat-tracing pipeline to further avoid the problem of flue gas crystallization.

[0026] In one technical solution of this utility model, the sampling transmission unit 1 further includes: a ceramic filter device 14, a backflush main pipe 15, backflush branch pipes 16, a first solenoid valve, and a compressor 17. The sampling probe 12 is provided with a ceramic filter device 14 to prevent large particles in the flue gas from entering the sampling probe 12 and causing blockage. Since large particles are blocked on the surface of the filter element of the ceramic filter device 14, the sampling flow rate decreases after long-term sampling, and the surface of the filter element of the ceramic filter device 14 needs to be purged periodically. One end of the backflush main pipe 15 is sealed, and the other end is connected to the air outlet of the compressor 17. The backflush main pipe 15 is provided with a first solenoid valve. Several backflush branch pipes 16 are provided on the backflush main pipe 15 located between the first solenoid valve and the sealed end. Each backflush branch pipe 16 is connected to a ceramic filter device 14.

[0027] In this invention, the calibration pipeline unit 2 consists of a standard gas pipeline 21 and several first sample transmission pipelines 22. Each first sample transmission pipeline 22 is connected to a transmission line 13, and a second solenoid valve is installed on each first sample transmission pipeline 22. A third solenoid valve is installed on the standard gas pipeline 21. The standard gas pipeline 21 located at the normally closed end of the third solenoid valve is connected to standard gas, which in this invention is nitric oxide and oxygen. The standard gas pipeline 21 located at the normally open end of the third solenoid valve is connected to air. The standard gas pipeline 21 located at the common end of the third solenoid valve has several standard gas branch pipes, each of which is connected to the corresponding first sample transmission pipeline 22 through the normally closed end of the second solenoid valve. The calibration pipeline unit 2 is used for the periodic calibration of instruments used for multi-point monitoring of denitrification, thereby ensuring that the dew points of flue gas and standard gas are consistent and avoiding measurement errors caused by inconsistencies in dew points. Generally, air calibration is performed once a day, and standard gas calibration is performed once a week. When calibrating with standard gas, the normally closed end of the third solenoid valve opens and the normally open end closes, while the normally closed end of the second solenoid valve opens and the normally open end closes, allowing standard gas to flow into the first sample transmission pipeline 22 to calibrate the instruments in the denitrification multi-point monitoring device. When calibrating with air, the normally closed end of the third solenoid valve closes and the normally open end opens, while the normally closed end of the second solenoid valve opens and the normally open end closes, allowing air to flow into the first sample transmission pipeline 22 to calibrate the instruments in the denitrification multi-point monitoring device. When sampling and transmitting, the normally closed end of the second solenoid valve closes and the normally open end opens, allowing flue gas to flow into the first sample transmission pipeline 22 for subsequent monitoring and analysis.

[0028] The sample pipeline processing unit 3 of this utility model includes: a second sample transmission pipeline 8, and an integrated condenser 5, an early warning unit 6, and a filter flow regulation unit 7 disposed on the second sample transmission pipeline 8. Flue gas flowing out of the calibration pipeline unit 2 enters the corresponding second sample transmission pipeline 8. The flue gas undergoes heat exchange and cooling via the integrated condenser 5. After cooling, the flue gas passes through the early warning unit 6 and then flows through the filter flow regulation unit 7 to filter out fine particulate matter. By employing a multi-channel integrated condenser 5, multiple flue gases can be condensed and dehydrated, avoiding the space constraints caused by using multiple condensers separately, and reducing the cabinet heat dissipation problems and high costs associated with multiple condensers. The early warning unit 6 can simultaneously monitor the pressure and dew point of the flue gas transmission pipeline before entering the analysis pipeline unit 4. On-site maintenance personnel can determine the blockage and dehydration status in the flue gas transmission channel based on the real-time pressure and dew point conditions, and take corresponding measures, reducing the workload of on-site troubleshooting and improving work efficiency.

[0029] like Figure 2 The integrated condenser 5 uses a compressor for refrigeration and consists of several three-port direct-cooling heat exchange tubes 51. Each three-port direct-cooling heat exchange tube 51 cools one type of flue gas. The upper end of the three-port direct-cooling heat exchange tube 51 is provided with an air inlet 511 and an air outlet 512, and the lower end of the three-port direct-cooling heat exchange tube 51 is provided with a drain outlet 513. The flue gas entering the second sample transfer pipeline 8 enters the three-port direct-cooling heat exchange tube 51 through the air inlet 511 for heat exchange, and enters the second sample transfer pipeline 8 side with the warning unit 6 through the air outlet 512. The drain outlet 513 is connected to a peristaltic pump 514 for continuous discharge of condensate to prevent condensate from accumulating at the bottom of the three-port direct-cooling heat exchange tube 51.

[0030] The early warning unit 6 consists of several sensor groups, each of which is installed on a second sample transfer pipeline 8. Each sensor group comprises a pressure sensor 61 and a dew point sensor 62. The early warning unit 6 monitors the pressure and dew point of the flue gas transfer pipeline before it enters the analysis pipeline unit 4. If the pressure in the flue gas transfer pipeline exceeds the standard, it may indicate a blockage. Backflushing of the filter element in the ceramic filter device 14 can be performed by checking the opening and closing of the first solenoid valve. If the backflushing effect is not significant, manual inspection of the specific location of the blockage is required, and the blockage must be cleared. If the dew point detected by the dew point sensor exceeds the standard, it may indicate incomplete dehydration of the flue gas. On-site maintenance personnel can check the drainage and cooling status of the integrated condenser 5.

[0031] Each second sample transfer pipe 8 is equipped with a filter flow regulation unit 7, such as Figure 3The filter flow regulation unit 7 includes a sampling pump 71, a glass fiber filter 72, and a flow meter 73. The sampling pump 71 is used to provide sampling power, the glass fiber filter 72 is used to filter fine particulate matter in the flue gas, and the flow meter 73 is used to control the flow rate of the flue gas entering the analysis pipeline unit 4, which is generally controlled at 20~90 liters / hour to ensure that the flue gas entering the analysis pipeline unit 4 is clean and dry, and to ensure the measurement accuracy of the analysis pipeline unit 4.

[0032] In this utility model, the analysis pipeline unit 4 is composed of several analysis pipelines 43. Each analysis pipeline 43 is connected to a second sample transfer pipeline 8. Each analysis pipeline 43 is equipped with a nitrogen oxide sensor 41 and an oxygen sensor 42 for analyzing the nitrogen oxide and oxygen concentrations in different zones of the same cross section of the denitrification device.

[0033] The above are merely preferred embodiments of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are within its protection scope. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should be considered within its protection scope.

Claims

1. A coal-fired power plant denitration multi-point monitoring device, characterized in that, The utility model relates to a kind of sampling transmission unit (1), calibration pipeline unit (2), sample pipeline processing unit (3) and analysis pipeline unit (4) comprising: the sampling transmission unit (1) is transmitted to calibration pipeline unit (2) by sampled flue gas, the dew point of flue gas is adjusted to be consistent with the dew point of calibration gas in calibration pipeline unit (2), the sample pipeline processing unit (3) is used to cool and filter flue gas from calibration pipeline unit (2) and is transmitted to analysis pipeline unit (4) to analyze the concentration of nitrogen oxide and oxygen concentration in flue gas. The sampling transmission unit (1) includes: sampling probe rod (11), sampling probe (12) and transmission pipeline (13), one end of the sampling probe (12) is connected with one end of sampling probe rod (11), the other end of the sampling probe rod (11) is inserted into the coal-fired power plant denitration device by the flange sleeve arranged on the coal-fired power plant denitration device;The other end of the sampling probe (12) is connected with one end of the transmission pipeline (13), and the other end of the transmission pipeline (13) is connected to the calibration pipeline unit (2).

2. The device for multi-point monitoring of denitration of a coal-fired power plant according to claim 1, characterized in that, The flange sleeve is provided with a heat preservation sleeve, the sampling probe (12) uses a heatable probe, and the transmission pipeline (13) uses a heat tracing pipeline.

3. The device for multi-point monitoring of denitration of a coal-fired power plant according to claim 2, characterized in that, Further comprising:

4. The device for multi-point monitoring of denitration of a coal-fired power plant according to claim 2, characterized in that, Ceramic filter device (14), back purge main pipe (15), back purge branch pipe (16), first solenoid valve and compressor (17), ceramic filter device (14) is arranged at the inlet of the sampling probe (12);One end of the back purge main pipe (15) is sealed, and the other end is connected to the air outlet of the compressor (17), the back purge main pipe (15) is provided with a first solenoid valve, a plurality of back purge branch pipes (16) are arranged on the back purge main pipe (15) between the first solenoid valve and the sealed end, and each back purge branch pipe (16) is connected to a ceramic filter device (14). The calibration pipeline unit (2) is composed of calibration gas pipeline (21) and a plurality of first sample transmission pipelines (22), each first sample transmission pipeline (22) is connected with a transmission pipeline (13), and the first sample transmission pipeline (22) is provided with a second solenoid valve;The calibration gas pipeline (21) is provided with a third solenoid valve, the calibration gas pipeline (21) connected to calibration gas at the normally closed end of the third solenoid valve, the calibration gas pipeline (21) connected to air at the normally open end of the third solenoid valve, and the calibration gas pipeline (21) provided with a plurality of calibration gas branch pipes at the common end of the third solenoid valve, each calibration gas branch pipe is connected to the corresponding first sample transmission pipeline (22) through the normally closed end of the second solenoid valve.

5. The device for multi-point monitoring of denitration of a coal-fired power plant according to claim 2, characterized in that, The sample pipeline processing unit (3) includes: second sample transmission pipeline (8) and integrated condenser (5), early warning unit (6) and filtering flow regulating unit (7) arranged on the second sample transmission pipeline (8), flue gas from the calibration pipeline unit (2) enters the corresponding second sample transmission pipeline (8), flue gas is heat-exchanged and cooled by integrated condenser (5), and the cooled flue gas flows through filtering flow regulating unit (7) after early warning unit (6).

6. The device for multi-point monitoring of denitration of a coal-fired power plant according to claim 5, characterized in that, ​ 7. The device for multi-point monitoring of denitration of a coal-fired power plant according to claim 6, characterized in that, The integrated condenser (5) is composed of several three-port direct-cooling heat exchange pipes (51), each of which cools one route of flue gas, the upper end of each three-port direct-cooling heat exchange pipe (51) is respectively provided with an air inlet (511) and an air outlet (512), and the lower end of each three-port direct-cooling heat exchange pipe (51) is provided with a liquid outlet (513), the flue gas entering the second sample transmission pipeline (8) enters the three-port direct-cooling heat exchange pipe (51) through the air inlet (511) to perform heat exchange, and then enters the side of the second sample transmission pipeline (8) provided with a warning unit (6) through the air outlet (512); the liquid outlet (513) is connected with a peristaltic pump (514).

8. The device for multi-point monitoring of denitration of a coal-fired power plant according to claim 6, characterized in that, The warning unit (6) is composed of several sensor groups, each of which is arranged on one route of the second sample transmission pipeline (8), and each sensor group is composed of a pressure sensor (61) and a dew point sensor (62).

9. The device for multi-point monitoring of denitration of a coal-fired power plant according to claim 6, characterized in that, Each second sample transmission pipeline (8) is provided with a filtering flow regulating unit (7), and the filtering flow regulating unit (7) comprises a sampling pump (71), a glass fiber screen filtering device (72) and a flowmeter (73).

10. The device for multi-point monitoring of denitration of a coal-fired power plant according to claim 6, characterized in that, The analysis pipeline unit (4) is composed of several analysis pipelines (43), each of which is connected with one second sample transmission pipeline (8), and each analysis pipeline (43) is provided with a nitrogen oxide sensor (41) and an oxygen sensor (42).

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