High-temperature flue gas sampling and analyzing system for circulating fluidized bed boiler

Abstract

The utility model relates to a high-temperature flue gas sampling and analyzing system for a circulating fluidized bed boiler. The system comprises a high-temperature-resistant sampling probe, a flue gas sampling measuring point assembly, a separator ash removal device, a first subsection heat tracing pipeline, a second subsection heat tracing pipeline, a third subsection heat tracing pipeline, a pretreatment device, a three-stage dust removal device and a flue gas analyzer. According to the utility model, the flue gas sampling measuring point assembly and the high-temperature-resistant sampling probe are arranged, and the separator ash removal device is configured for flue gas ash removal, so that reliable and continuous sampling of high-temperature flue gas is realized; segmental heat tracing is carried out in the whole process of flue gas sampling, treatment, analysis and the like, so that pollutants such as SO2, NOX and the like are accurately measured; by observing the color of the glass balls and the cleanliness of the fibers in the pretreatment device, the problems of large sampling analysis deviation of the high-temperature flue gas and the like are greatly reduced, and orderly implementation of original emission measurement of pollutants is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of pollutant measurement, and particularly to a high-temperature flue gas sampling and analysis system for a circulating fluidized bed boiler. Background Technique

[0002] Circulating fluidized bed (CFB) boilers are the main way for the clean and efficient utilization of low-calorific value fuels and have now become an important part of thermal power generation in China. CFB boilers have a low combustion temperature and a strong reducing atmosphere in the furnace, with inherent advantages in pollutant emissions and control costs. However, with the gradual tightening of air pollutant emission standards, especially ultra-low emissions, quite a number of boilers have to add off-furnace desulfurization and denitrification facilities, making their advantages no longer exist. In order to further explore the potential of pollutant emission control in CFB boilers, deeply study the distribution and variation law of pollutants in flue gas, and propose pollutant emission control measures under complex furnace atmosphere conditions, it is very necessary to measure and study the original pollutant emissions.

[0003] CFB boilers usually adopt pollutant control processes such as in-furnace calcium injection for desulfurization, low-temperature staged combustion for nitrogen inhibition, and SNCR denitrification. Its remarkable feature is that the removal reactions of pollutants such as SO2 and NO X mostly take place in high-temperature (≥800°C) and high-ash concentration areas such as the furnace and separator. Therefore, the original pollutant emissions should be measured at parts such as the boiler furnace and separator. At present, the measurement of pollutant emissions from power station boilers is mainly carried out in low-temperature (≤500°C) and low-ash concentration areas of equipment such as their tails, desulfurization, and dust removal devices. Continuous automatic on-line monitoring of air pollutants is generally arranged at the chimney inlet. Existing flue gas sampling usually adopts the method of inserting a probe into the flue or chimney for extraction. As Figure 4 shown, after the flue gas passes through the sampling probe 10, the heating pipeline 20, and the pretreatment device 30, it enters the flue gas analyzer 40 for analysis to obtain the concentrations of pollutants such as SO2 and NO X and so on.

[0004] In the existing flue gas sampling and analysis method for pollutant measurement, the sampling probe generally works in areas with a temperature below 500°C and a low ash concentration. When sampling in high-temperature and high-ash concentration areas such as the CFB boiler furnace, problems such as the probe being burned red, severely deformed, and the pipe being blocked will occur, which cannot meet the requirements of high temperature and high ash concentration in the CFB boiler furnace and separator. This directly affects the flue gas sampling process and the actual sampling effect, resulting in large flue gas sampling deviations and damaging the flue gas analyzer at the same time. In addition, it is very difficult for the heating pipeline in existing flue gas sampling to achieve the heating effect for the whole process of flue gas sampling, treatment, and analysis, and it is extremely easy to cause inaccurate pollutant measurement due to the phenomenon of SO2 and other substances dissolving in water. Content of the Utility Model

[0005] To solve the above technical problems, the utility model provides a high-temperature flue gas sampling and analysis system for a circulating fluidized bed boiler to meet the measurement and research needs of the original emissions of pollutants.

[0006] To achieve the above object, the utility model provides a high-temperature flue gas sampling and analysis system for a circulating fluidized bed boiler. The system includes a high-temperature resistant sampling probe, a flue gas sampling measuring point assembly, a separator ash removal device, a first segmented heat tracing pipeline, a second segmented heat tracing pipeline, a third segmented heat tracing pipeline, a pretreatment device, a three-stage dust removal device, and a flue gas analyzer; one end of the high-temperature resistant sampling probe is located inside the flue gas sampling measuring point assembly, and the other end is connected to the separator ash removal device; the separator ash removal device is connected to the pretreatment device through the first segmented heat tracing pipeline; the pretreatment device is connected to the three-stage dust removal device through the second segmented heat tracing pipeline; the three-stage dust removal device is connected to a vacuum pump through the third segmented heat tracing pipeline; the vacuum pump is connected to a three-way valve; the three-way valve is connected to the flue gas analyzer; the high-temperature resistant sampling probe is a heat-resistant stainless steel pipe, the wall thickness of the heat-resistant stainless steel pipe is ≥3 mm, the inner diameter is 8-10 mm, and the outer diameter is ≤18 mm.

[0007] Optionally, a through hole matching the flue gas sampling measuring point assembly is opened on the water wall fin of the circulating fluidized bed boiler, and the flue gas sampling measuring point assembly is fixed outside the through hole of the water wall fin.

[0008] Optionally, the flue gas sampling measuring point assembly includes a stainless steel pipe and a stainless steel ball valve; the stainless steel pipe is fixed outside the through hole of the water wall fin; the inner diameter of the stainless steel pipe is 19-22 mm, the outer diameter is 23-25 mm, and the wall thickness is 2-3 mm.

[0009] Optionally, the stainless steel pipe and the stainless steel ball valve are made of the same stainless steel material, including one of 304H, 321H, 309S, and 310S.

[0010] Optionally, the material of the heat-resistant stainless steel pipe includes one of 304H, 321H, 309S, and 310S;

[0011] Optionally, the high-temperature resistant sampling probe is composed of a plurality of heat-resistant stainless steel pipes, and the plurality of heat-resistant stainless steel pipes are connected by screw threads.

[0012] Optionally, the separator ash removal device is connected to the high-temperature resistant sampling probe by screw threads.

[0013] Optionally, the pretreatment device includes a filter, a flow detector, and a temperature detector; the ash removal device of the separator is connected to the filter of the pretreatment device through the first segmented heat tracing pipeline; the flow detector of the pretreatment device is connected to the three-stage dust removal device through the second segmented heat tracing pipeline.

[0014] Optionally, the filter includes glass balls and fibers.

[0015] Optionally, the first segmented heat tracing pipeline, the second segmented heat tracing pipeline, and the third segmented heat tracing pipeline each independently include a silica gel tube, an electric heating tape, a glass fiber cloth, and a rubber sheet from the inside to the outside in sequence.

[0016] Optionally, the electric heating tape is coated on the surface of the silica gel tube, the glass fiber cloth is coated on the surface of the electric heating tape, and the rubber sheet is coated on the surface of the glass fiber cloth.

[0017] Through the above technical solution, the utility model realizes reliable continuous sampling of high-temperature flue gas by setting up a flue gas sampling measuring point assembly, using heat-resistant stainless steel to make a high-temperature resistant sampling probe with a thick wall pipe and a certain pipe diameter, and configuring an ash removal device for the separator to remove ash from the flue gas; segmented heat tracing is carried out during the whole process of flue gas sampling, treatment, and analysis, achieving accurate measurement of pollutants such as SO2 and NO X etc.; by observing the color of the glass balls and the cleanliness of the fibers in the pretreatment device and replacing them in time, problems such as large deviation in high-temperature flue gas sampling analysis are greatly reduced, ensuring the orderly implementation of the measurement of the original emissions of pollutants.

[0018] Other features and advantages of the utility model will be described in detail in the subsequent specific implementation part. Brief Description of the Drawings

[0019] The drawings are used to provide a further understanding of the utility model, and constitute a part of the specification, and are used together with the following specific implementation to explain the utility model, but do not constitute a limitation to the utility model. In the drawings:

[0020] Figure 1 is a schematic diagram of the high-temperature flue gas sampling and analysis system of the CFB boiler of the utility model;

[0021] Figure 2 is a schematic diagram of the flue gas sampling measuring point assembly of the utility model;

[0022] Figure 3 is a schematic diagram of the structure of the segmented heat tracing pipeline of the utility model;

[0023] Figure 4 is a schematic diagram of the pollutant measurement and sampling analysis device of the power station boiler in the prior art.

[0024] Description of the Reference Numerals

[0025] 10 - Sampling probe; 20 - Heat - tracing pipeline; 30 - Pretreatment device; 40 - Flue gas analyzer;

[0026] 1 - High - temperature resistant sampling probe; 2 - Flue gas sampling measuring point assembly; 3 - Separator ash removal device; 41 - First segmented heat - tracing pipeline; 42 - Second segmented heat - tracing pipeline; 43 - Third segmented heat - tracing pipeline; 5 - Pretreatment device; 6 - Three - stage dust removal device; 7 - Vacuum pump; 8 - Three - way valve; 9 - Flue gas analyzer. Detailed implementation manners

[0027] The following will describe in detail the specific implementation manners of the present utility model with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only for the purpose of illustration and explanation of the present utility model, and are not used to limit the present utility model.

[0028] The present utility model provides a high - temperature flue gas sampling and analysis system for a circulating fluidized bed boiler. As Figure 1 shown, the system includes a high - temperature resistant sampling probe 1, a flue gas sampling measuring point assembly 2, a separator ash removal device 3, a first segmented heat - tracing pipeline 41, a second segmented heat - tracing pipeline 42, a third segmented heat - tracing pipeline 43, a pretreatment device 5, a three - stage dust removal device 6 and a flue gas analyzer 9; one end of the high - temperature resistant sampling probe 1 is located inside the flue gas sampling measuring point assembly 2, and the other end is connected to the separator ash removal device 3; the separator ash removal device 3 is connected to the pretreatment device 5 through the first segmented heat - tracing pipeline 41; the pretreatment device 5 is connected to the three - stage dust removal device 6 through the second segmented heat - tracing pipeline 42; the three - stage dust removal device 6 is connected to a vacuum pump 7 through the third segmented heat - tracing pipeline 43; the vacuum pump 7 is connected to a three - way valve 8; the three - way valve 8 is connected to the flue gas analyzer 9; the high - temperature resistant sampling probe 1 is a heat - resistant stainless - steel pipe, the wall thickness of the heat - resistant stainless - steel pipe is ≥3 mm, the inner diameter is 8 - 10 mm, and the outer diameter is ≤18 mm.

[0029] In the present utility model, by setting up a flue gas sampling measuring point assembly, using heat - resistant stainless steel to make a high - temperature resistant sampling probe with a thick wall and a certain pipe diameter, and configuring a separator ash removal device for flue gas ash removal, reliable and continuous sampling of high - temperature flue gas is achieved; heat tracing is carried out in segments during the whole process of flue gas sampling, treatment and analysis, achieving accurate measurement of pollutants such as SO2, NO X etc.; by observing the color of the glass balls and the fiber cleanliness in the pretreatment device and replacing them in time, problems such as large deviation in high - temperature flue gas sampling and analysis are greatly reduced, ensuring the orderly implementation of the measurement of the original emissions of pollutants.

[0030] In one implementation manner, as Figure 2As shown, through holes matching the flue gas sampling measurement point assembly 2 are formed in the water wall fins of the circulating fluidized bed boiler, and the flue gas sampling measurement point assembly 2 is fixed outside the through holes of the water wall fins. Setting the flue gas sampling measurement point assembly on the water wall fins of the CFB boiler can accurately measure the original emission concentration of pollutants. The measurement point assembly is welded and fixed on the water wall fins with a stainless steel pipe and a stainless steel ball valve, which can achieve reliable sampling and isolation of high-temperature flue gas.

[0031] In one embodiment, the inner diameter of the stainless steel pipe is 19 - 22 mm, the outer diameter is 23 - 25 mm, and the wall thickness is 2 - 3 mm.

[0032] In one embodiment, the stainless steel pipe and the stainless steel ball valve are made of the same type of stainless steel, including one of 304H, 321H, 309S, and 310S; preferably 304H.

[0033] In one embodiment, the material of the heat-resistant stainless steel pipe includes one of 304H, 321H, 309S, and 310S; preferably 310S. As a high-temperature resistant sampling probe, the heat-resistant stainless steel pipe has a higher heat-resistant temperature and lasting strength compared with the existing sampling probes. During the high-temperature flue gas sampling and analysis process of the CFB boiler, regularly rotating the sampling probe ensures its reliable use and prevents serious deformation of the probe, thus avoiding the measurement interruption problem caused by the severe deformation of the sampling probe that cannot be withdrawn.

[0034] In one embodiment, the high-temperature resistant sampling probe 1 is optionally composed of a plurality of heat-resistant stainless steel pipes, and the plurality of heat-resistant stainless steel pipes are connected by screw threads.

[0035] In one embodiment, the separator ash removal device 3 uses the cyclone separation principle to achieve the purpose of high-temperature flue gas ash removal, and the separator ash removal device 3 is connected to the high-temperature resistant sampling probe 1 by screw threads. The high-temperature flue gas ejected from the positive-pressure furnace flue gas sampling measurement point of the CFB boiler carries solid materials, and gas-solid separation is achieved under the action of the separator ash removal device. At the lower positive-pressure part, the vacuum pump can be opened to ensure the flue gas flow rate and ash removal effect, thus effectively solving problems such as probe and pipeline blockage.

[0036] In one embodiment, the pretreatment device 5 includes a filter, a flow detector, and a temperature detector; the separator ash removal device 3 is connected to the filter of the pretreatment device 5 through the first segmented tracing pipeline 41; the flow detector of the pretreatment device 5 is connected to the three-stage dust removal device 6 through the second segmented tracing pipeline 42.

[0037] In one embodiment, the filter includes glass balls and fibers. Using the multi-stage principle of glass balls and fibers to filter flue gas plays a key role in removing water and dust from the flue gas and is also an important measure to protect the flue gas analyzer. During the original emission measurement of a CFB boiler, by means of auxiliary measures such as regularly cleaning the ash accumulation, checking and replacing the color of the glass balls and the cleanliness of the fibers, problems such as large deviations in the sampling and analysis of high-temperature flue gas are greatly reduced, effectively ensuring the smooth progress and implementation of on-site measurement work.

[0038] In one embodiment, the three-stage dust removal device 6 includes filter cotton for dust removal; the three-stage dust removal device 6 can perform secondary filtering (dust removal) to ensure the cleanliness of the flue gas and avoid the occurrence of dust blockage.

[0039] In one embodiment, as Figure 3 shown, the first segmented heating pipeline 41, the second segmented heating pipeline 42, and the third segmented heating pipeline 43 each independently include a silica gel tube, an electric heating tape, a glass fiber cloth, and a rubber sheet from the inside to the outside in sequence. The electric heating tape is coated on the surface of the silica gel tube, the glass fiber cloth is coated on the surface of the electric heating tape, and the rubber sheet is coated on the surface of the glass fiber cloth. During the whole process of high-temperature flue gas sampling, treatment, and analysis, the simple segmented heating method is adopted to further reduce the condensation phenomenon of water vapor in the flue gas, thereby effectively avoiding the occurrence of the phenomenon that pollutants such as SO2 dissolve in water, and further ensuring the accuracy of the original emission measurement of pollutants.

[0040] When the on-site measurement of the present utility model is carried out, first, preparatory work such as checking the integrity of equipment and instruments, pipeline connection, and instrument calibration is carried out, and the high-temperature flue gas sampling and analysis system is correctly connected as Figure 1 shown, and the flue gas analyzer 9 is started to check whether there are problems such as air leakage in the whole process flow; secondly, the first segmented heating pipeline 41, the second segmented heating pipeline 42, and the third segmented heating pipeline 43 are energized for preheating in advance, the pretreatment device 5 and the vacuum pump 7 are started, and the air volume entering the flue gas analyzer 9 is adjusted to prevent damage to the equipment; thirdly, the high-temperature resistant sampling probe 1 is inserted into the flue gas sampling measuring point assembly 2, and it is checked that the flue gas temperature in the pretreatment device 5 is above 180°C and the flow rate is normal, and the color of all glass balls is dark blue and the fibers are clean, etc.; finally, it is observed that the flue gas temperature and flow rate in the flue gas analyzer 9 meet the actual requirements, and the detection data of pollutants such as SO2 and NO X change normally, and relevant data are recorded after at least one peak-valley cycle of fluctuation is stable.

[0041] During the on-site measurement of the present utility model, after the high-temperature sampling probe 1 extends into the flue gas sampling measuring point assembly 2, it rotates 180° every 2 - 3 minutes. The tube is automatically corrected by using the phenomenon of high-temperature bending of the high-temperature sampling probe 1. The longer the extension length of the high-temperature sampling probe 1, the faster its rotation frequency should be. After each measuring point is measured, the ash deposited at the lower part of the separator ash removal device 3 should be cleaned in time to avoid the influence of ash in the sampled flue gas on the accuracy of pollutant measurement and blockage of the connecting pipeline. Regularly check the color of the glass balls and the cleanliness of the fibers of the pretreatment device 5, etc. If any abnormality is found, suspend the measurement and replace it in time to ensure the accuracy of pollutant emission measurement. During the measurement of the original emissions of pollutants from CFB boilers, the high-temperature flue gas sampling at each measuring point should be carried out at three depths of 0.5 m, 1 m, and 1.5 m, and three groups of test data are selected for each depth and averaged to obtain the distribution and change of pollutants in the flue gas.

[0042] The preferred embodiments of the present utility model have been described in detail above in conjunction with the accompanying drawings. However, the present utility model is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present utility model, various simple modifications can be made to the technical solutions of the present utility model, and these simple modifications all belong to the protection scope of the present utility model.

[0043] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present utility model will not separately describe various possible combination methods.

[0044] Furthermore, any combination can be made between different embodiments of the present utility model as long as it does not violate the idea of the present utility model, and it should also be regarded as the content disclosed by the present utility model.

Claims

1. A circulating fluidized bed boiler high temperature flue gas sampling and analysis system, characterized in that: The system comprises a high temperature resistant sampling probe (1), a flue gas sampling measuring point assembly (2), a separator ash removal device (3), a first segmented heating pipeline (41), a second segmented heating pipeline (42), a third segmented heating pipeline (43), a pretreatment device (5), a three-stage dust removal device (6) and a flue gas analyzer (9); One end of the high temperature resistant sampling probe (1) is located in the flue gas sampling measuring point assembly (2), and the other end is connected to the separator ash removal device (3); the separator ash removal device (3) is connected to the pretreatment device (5) through the first segmented heating pipeline (41); the pretreatment device (5) is connected to the three-stage dust removal device (6) through the second segmented heating pipeline (42); the three-stage dust removal device (6) is connected to the vacuum pump (7) through the third segmented heating pipeline (43); the vacuum pump (7) is connected to the three-way valve (8); the three-way valve (8) is connected to the flue gas analyzer (9); The high temperature resistant sampling probe (1) is a heat resistant stainless steel tube, the tube wall thickness of the heat resistant stainless steel tube is ≥3 mm, the inner diameter is 8-10 mm, and the outer diameter is ≤18 mm.

2. The high temperature flue gas sampling and analysis system according to claim 1, characterized in that: The water-cooled wall fins of the circulating fluidized bed boiler are provided with through holes matching the flue gas sampling and measuring point components (2), and the flue gas sampling and measuring point components (2) are fixed outside the through holes of the water-cooled wall fins.

3. The high temperature flue gas sampling and analysis system according to claim 2, characterized in that: The flue gas sampling measuring point assembly (2) comprises a stainless steel pipe and a stainless steel ball valve; the stainless steel pipe is fixed outside the through hole of the water-cooled wall fin; The inner diameter of the stainless steel tube is 19-22 mm, the outer diameter is 23-25 ​​mm, and the tube wall thickness is 2-3 mm.

4. The high-temperature flue gas sampling and analysis system according to claim 3, characterized in that: The stainless steel pipe and the stainless steel ball valve are made of the same stainless steel material, including one of 304H, 321H, 309S, and 310S.

5. The high temperature flue gas sampling and analysis system according to claim 1, characterized in that: The material of the heat-resistant stainless steel pipe includes one of 304H, 321H, 309S, and 310S; The high temperature resistant sampling probe (1) may optionally be composed of a plurality of heat resistant stainless steel tubes, wherein the plurality of heat resistant stainless steel tubes are connected by threads.

6. The high temperature flue gas sampling and analysis system according to claim 1, characterized in that: The separator ash removal device (3) is connected to the high temperature resistant sampling probe (1) via a threaded connection.

7. The high temperature flue gas sampling and analysis system according to claim 1, characterized in that: The pretreatment device (5) comprises a filter, a flow detector and a temperature detector; The separator dust removal device (3) is connected to the filter of the pretreatment device (5) via the first segmented heating pipeline (41); the flow detector of the pretreatment device (5) is connected to the third-stage dust removal device (6) via the second segmented heating pipeline (42).

8. The high-temperature flue gas sampling and analysis system according to claim 7, characterized in that: The filter includes glass balls and fibers.

9. The high-temperature flue gas sampling and analysis system according to claim 1, characterized in that: The first segmented heating pipeline (41), the second segmented heating pipeline (42) and the third segmented heating pipeline (43) each independently include a silicone tube, an electric heating tape, a glass fiber cloth and a rubber sheet in order from the inside to the outside.

10. The high temperature flue gas sampling and analysis system according to claim 9, characterized in that: The electric heating belt is coated on the surface of the silicone tube, the glass cloth is coated on the surface of the electric heating belt, and the rubber is coated on the surface of the glass cloth.

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