Online monitoring and sampling treatment device for calorific value of mixed gas

Abstract

The invention discloses a mixed gas calorific value on-line monitoring sampling processing device, and relates to the technical field of on-line analysis instrument measurement, the mixed gas calorific value on-line monitoring sampling processing device comprises a mixed gas pipeline, an outlet of the mixed gas pipeline is provided with a dust separation cover, and a first sampling probe rod, a second sampling probe rod and a third sampling probe rod with different depths are respectively inserted on the dust separation cover; sample gas outlets of the first sampling probe rod, the second sampling probe rod and the third sampling probe rod are respectively connected with a first external filter, a second external filter and a third external filter, and sample gas outlets of the first external filter, the second external filter and the third external filter are converged and then connected with a self-regulating electric tracing pipe cable; according to the device, the blockage of the sampling pipeline and the sampling probe is effectively avoided, the separation of impurities in the sample gas is realized through the synergistic effect of the vortex condenser and the high-precision filter, and the accuracy of the measurement of the calorific value of the mixed gas is improved.

Description

Technical Field

[0001] This invention relates to the field of online analytical instrument measurement technology, and in particular to an online monitoring and sampling processing device for the calorific value of mixed coal gas. Background Technology

[0002] The steel industry uses a large amount of secondary energy gaseous fuels, especially blast furnace gas, coke oven gas, converter gas, gasifier gas, natural gas, or a mixture of several of these. Fully recovering and utilizing these mixed gases is of great significance for improving the economic efficiency of enterprises. The calorific value of mixed gas is the most important quality indicator of fuel gas. Currently, component analysis is commonly used to measure the calorific value of mixed gas. Component analysis is a method that involves online continuous detection of various major components in mixed gas. Based on the standard calorific value content of each gas component and its percentage in the mixed gas, computer numerical simulation calculations are used to directly detect the calorific value of the mixed gas. However, when conducting calorific value testing, there are common problems such as the sampled gas not being representative, the inability to effectively separate impurities such as tar and naphthalene from the sampled gas, easy blockage of the sampling probe and sampling pipeline leading to sampling interruption, and inaccurate calorific value measurements. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides an online monitoring and sampling device for the calorific value of mixed coal gas. This device solves the problems of unrepresentative sample gas collected during the measurement of the calorific value of mixed coal gas, easy blockage of sampling pipelines and sampling probes, inability to effectively separate impurities in the collected sample gas, and inaccurate calorific value measurement.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows: A mixed gas calorific value online monitoring and sampling processing device includes a mixed gas pipeline. A dust separation hood is installed at the outlet of the mixed gas pipeline. A first sampling probe, a second sampling probe, and a third sampling probe of different depths are respectively inserted into the dust separation hood. The sample gas outlets of the first, second, and third sampling probes are respectively connected to a first external filter, a second external filter, and a third external filter. The sample gas outlets of the first, second, and third external filters merge and are connected to a self-regulating electric heat tracing cable. The outlet of the self-regulating electric heat tracing cable is connected to a laser analyzer component for monitoring the calorific value of the mixed gas.

[0005] Furthermore, the laser analyzer assembly includes a laser analyzer protective case, inside which a vortex condenser and a laser gas analyzer are installed. The outlet of the self-regulating electric heating cable passes through the wall of the laser analyzer protective case and connects to the inlet of the vortex condenser. The nitrogen inlet of the vortex condenser is connected to a nitrogen pipe, and the inlet of the nitrogen pipe is connected to a pre-purge box for providing nitrogen. A first filter pressure reducing valve is installed on the nitrogen pipe. The sample gas outlet of the vortex condenser is connected to a high-precision filter, and the outlet of the high-precision filter is connected to the laser gas analyzer. The condensate outlet of the vortex condenser is connected to a peristaltic pump, and the outlet of the peristaltic pump is connected to a drain pipe. The drain pipe passes through the wall of the laser analyzer protective case and connects to a waste liquid pool.

[0006] Furthermore, the pre-purge box includes a second nitrogen inlet pipe connected to a nitrogen source. A nitrogen control valve is installed on the second nitrogen inlet pipe. The outlet of the second nitrogen inlet pipe is divided into two branches. One branch is connected to the inlet of the nitrogen pipe, and the other branch is connected to a second filter pressure reducing valve. A pressure switch is connected to the outlet of the second filter pressure reducing valve. An oil mist filter is connected to the pressure output terminal of the pressure switch. A second solenoid valve is installed at the outlet of the oil mist filter. A fifth solenoid valve, a third solenoid valve, and a fourth solenoid valve are respectively connected to the outlet of the second solenoid valve. An exhaust pipe is connected to the outlet of the fifth solenoid valve. The backflush interface of the first external filter, the second external filter, and the third external filter is respectively connected to the outlet of the third solenoid valve. The outlet of the fourth solenoid valve is connected to a self-regulating electric heat tracing cable. A first solenoid valve is installed on the self-regulating electric heat tracing cable.

[0007] Furthermore, the first sampling probe, the second sampling probe, and the third sampling probe are located at the center, 1 / 3 of the radius, and 2 / 3 of the radius of the mixed gas pipeline, respectively.

[0008] Furthermore, the insertion depth of the first sampling probe, the second sampling probe, and the third sampling probe decreases from the center of the pipe to both sides.

[0009] Furthermore, it also includes a PLC controller installed inside the protective box of the laser analyzer. The control terminal of the PLC controller is connected to the control terminals of the first, second, third, fourth, and fifth pressure switch solenoid valves respectively after passing through the wall of the protective box of the laser analyzer via a cable.

[0010] Furthermore, the laser gas analyzer includes an external measuring gas chamber, the inlet of which is connected to the outlet of a high-precision filter. The two ends of the external measuring gas chamber are respectively provided with a laser emitting end and a laser receiving end arranged opposite to each other. The outlet of the external measuring gas chamber is connected to an exhaust pipe. The outlet of the exhaust pipe passes through the wall of the protective box of the laser analyzer and is connected to a pneumatic sampling pump. The inlet of the pneumatic sampling pump is connected to a first nitrogen inlet pipe.

[0011] Furthermore, a first through-hole ball valve is installed between the first sampling probe and the first external filter, a second through-hole ball valve is installed between the second sampling probe and the second external filter, and a third through-hole ball valve is installed between the third sampling probe and the third external filter.

[0012] Furthermore, the pressure output terminal of the pressure switch is also connected to an air storage tank, the outlet of the air storage tank is connected to a drain pipe, and a shut-off valve is installed on the drain pipe.

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. By inserting first, second, and third sampling probes of different depths into the dust separation hood at the outlet of the mixed gas pipeline, it is possible to address the issue that the different components in the mixed gas cause stratification within the pipeline, with lighter components distributed at the pipeline outlet and heavier components distributed deeper within the pipeline. The probes of different insertion depths can collect samples from different depths within the pipeline, making the collected gas samples more representative. Furthermore, the three sampling probes prevent sampling interruptions caused by blockage of a single probe. To address the technical challenges and ensure the continuity of sample gas collection, the sample gas is filtered through a first, second, and third external filter to remove large particulate impurities, preventing them from entering subsequent equipment. The filtered sample gas then merges and enters a self-regulating electric heating cable. The sample gas passing through the self-regulating electric heating cable enters the laser analyzer component for analysis. The self-regulating electric heating cable heats the sample gas inside, preventing condensation and blockage during transport, thus solving the problem of easy blockage in existing sampling pipelines.

[0014] 2. By installing a vortex condenser and a laser gas analyzer inside the protective enclosure of the laser analyzer, the nitrogen inlet of the vortex condenser is connected to a nitrogen pipe. A first filter and pressure reducing valve is installed on the nitrogen pipe. This valve filters the nitrogen supplied from the pre-purge chamber, preventing impurities from entering the vortex condenser. It also reduces the pressure of the gas entering the pre-purge chamber, ensuring the pressure matches the vortex condenser's rated pressure. This provides a cooling gas source for the vortex condenser, preventing impurities such as moisture and tar droplets from entering the sample gas, which can easily distort the absorption signal and affect the accuracy of component concentration and calorific value calculations. The condenser condenses the components more effectively, and the liquefied liquid settles in the vortex condenser before being continuously discharged from the drain pipe via a peristaltic pump. This ensures that the sample gas treated by the vortex condenser is dry, solving the problem of ineffective separation of impurities in the collected sample gas. The sample gas after passing through the vortex condenser enters a high-precision filter, which intercepts ultrafine impurities that were not completely removed by the vortex condenser, providing clean sample gas for laser gas analyzer detection. The sample gas after passing through the high-precision filter enters the laser gas analyzer for calorific value detection. The synergistic effect of the vortex condenser and the high-precision filter achieves efficient separation of impurities in the sample gas, improving the accuracy of mixed gas calorific value measurement.

[0015] 3. By setting up a pre-purge box, the second nitrogen inlet pipe of the pre-purge box is connected to the nitrogen pipe to provide a cooling gas source for the scroll condenser. Simultaneously, the second nitrogen inlet pipe is connected to the second filter pressure reducing valve to provide a purge gas source for backflush. When providing a cooling gas source for the scroll condenser, the nitrogen control valve is opened, and nitrogen enters the nitrogen pipe after passing through the second nitrogen inlet pipe to provide a cooling gas source for the scroll condenser. When providing a gas source for backflush, the nitrogen control valve is opened, and nitrogen enters the second filter pressure reducing valve, pressure switch, oil mist filter, and second solenoid valve sequentially through the second nitrogen inlet pipe. The nitrogen passing through the second solenoid valve is divided into three paths. After the fifth solenoid valve of the first branch is opened, nitrogen is discharged from the exhaust pipe. After the third solenoid valve of the second branch is opened, nitrogen enters the first external filter, the second filter pressure reducing valve, and the second filter pressure reducing valve. After the backflush interface of the external filter and the third external filter, the external backflush of the first external filter, the second external filter and the third external filter are performed. After the fourth solenoid valve of the third branch is opened, nitrogen gas enters the self-regulating electric heating cable in reverse and then enters the sample gas outlet of the first external filter, the second external filter and the third external filter. Finally, the nitrogen gas enters the first sampling probe, the second sampling probe and the third sampling probe respectively to achieve internal backflush. By reversing the flow of nitrogen gas, the external backflush and internal backflush of the sampling pipeline are achieved. The impact force of the nitrogen gas flow blows the impurities attached to the sampling pipeline and the sampling probe away from the original flow path, reducing the blockage of the sampling pipeline and the sampling probe and keeping the sampling pipeline and the sampling probe unobstructed.

[0016] 4. The first, second, and third sampling probes are inserted into the center, 1 / 3, and 2 / 3 of the radius of the radial semicircle on the dust separation hood. Due to the flow of mixed gas in the pipeline, the uniformity of the sample gas in the mixed gas pipeline is inconsistent. The sample gas flow rate is the fastest and the composition is more uniform in the center of the mixed gas pipeline, while the sample gas flow rate is slower near the pipe wall and the sample gas is prone to stratification. By collecting sample gas from the center and both sides of the mixed gas pipeline at the same time, the sampling probes can collect sample gas from different locations, making the collected sample gas more representative.

[0017] 5. The PLC controller automatically controls the opening and closing of the pressure switch, the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve, and the fifth solenoid valve according to the internal program, so as to realize the automatic control of the start and stop of the backflushing process.

[0018] 6. By connecting the outlet of the laser gas analyzer to the exhaust pipe, and the exhaust pipe passing through the wall of the laser analyzer's protective box and then connecting to the pneumatic sampling pump, the continuous negative pressure generated by the pneumatic sampling pump promptly extracts the waste gas detected by the laser gas analyzer and exhausts it through the outlet of the pneumatic sampling pump, reducing the retention of sample gas in the laser gas analyzer.

[0019] 7. By setting a first through-hole ball valve between the first sampling probe and the first external filter, a second through-hole ball valve between the second sampling probe and the second external filter, and a third through-hole ball valve between the third sampling probe and the third external filter, each through-hole ball valve controls the on / off state of each sampling branch. Opening a single through-hole ball valve enables single-point depth sampling, while opening two or three through-hole ball valves simultaneously enables multi-depth composite sampling. If a sampling probe is blocked, the through-hole ball valve can be closed, allowing for isolated cleaning of one sampling probe without shutting down the entire sampling system. The through-hole ball valves of other branches can be opened normally, ensuring the continuity of sample gas collection and avoiding detection interruptions due to maintenance of a single branch. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention.

[0021] In the picture: 1. First sampling probe; 2. Second sampling probe; 3. Third sampling probe; 4. Third external filter; 5. Second external filter; 6. First external filter; 7. Self-regulating electric heating cable; 8. First solenoid valve; 10. Vortex condenser; 11. High-precision filter; 12. Peristaltic pump; 13. Drain pipe; 14. Laser emitter; 15. External measuring gas chamber; 16. Laser receiver; 17. Exhaust pipe; 18. Pneumatic sampling pump; 19. First nitrogen inlet pipe; 20. Laser analyzer protective case; 21. Cable; 22. Gas storage tank; 3. Pressure switch; 24. Oil mist filter; 25. Third solenoid valve; 26. Fourth solenoid valve; 27. Fifth solenoid valve; 28. Second solenoid valve; 29. ​​Second filter pressure reducing valve; 30. PLC controller; 31. Pre-purge box; 32. Mixed gas pipeline; 33. First through-hole ball valve; 34. Second through-hole ball valve; 35. Third through-hole ball valve; 36. Shut-off valve; 37. First filter pressure reducing valve; 38. Nitrogen pipe; 39. Laser gas analyzer; 40. Second nitrogen inlet pipe; 41. Nitrogen control valve; 42. Drain pipe; 43. Exhaust pipe. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0023] like Figure 1As shown, an online monitoring and sampling device for the calorific value of mixed gas includes a mixed gas pipeline 32. A dust separation hood is installed at the outlet of the mixed gas pipeline 32. A first sampling probe 1, a second sampling probe 2, and a third sampling probe 3 at different depths are inserted into the dust separation hood. Due to the different components in the mixed gas, the components of the mixed gas are prone to stratification within the pipeline. Lighter components are distributed at the outlet of the mixed gas pipeline 32, while heavier components are distributed at deeper positions within the pipeline. Probes with different insertion depths can collect components at different depths within the pipeline, making the collected gas sample more representative. Simultaneously, the three sampling probes avoid the technical problem of sampling interruption caused by blockage of a single sampling probe, ensuring the continuity of gas sample collection. The gas outlets of the first sampling probe 1, the second sampling probe 2, and the third sampling probe 3... The system is equipped with a first external filter 6, a second external filter 5, and a third external filter 4, respectively. After sampling, the sample gas passes through these filters to remove large particulate impurities, preventing them from entering subsequent equipment. The outlets of the sample gas from these filters converge and connect to a self-regulating electric heating cable 7 (model: 316L8). The outlet of the self-regulating electric heating cable 7 is connected to a laser analyzer assembly for monitoring the calorific value of the mixed gas. The sample gas after passing through the self-regulating electric heating cable 7 enters the laser analyzer assembly for analysis. The self-regulating electric heating cable 7 heats the sample gas inside, preventing condensation during transport and thus avoiding pipe blockage. This solves the problem of easy blockage in existing sampling pipelines.

[0024] The laser analyzer assembly includes a laser analyzer protective case 20. Inside the protective case 20 are a vortex condenser 10 and a laser gas analyzer 39. The vortex condenser 10 condenses easily condensable components in the sample gas, such as moisture and tar droplets, which can cause absorption signal distortion and affect the accuracy of component concentration and calorific value calculations. The liquefied liquid settles in the vortex condenser 10, solving the problem of ineffective separation of impurities in the collected sample gas. The outlet of the self-regulating electric heating cable 7 passes through the wall of the laser analyzer protective case 20 and connects to the inlet of the vortex condenser 10. The nitrogen inlet of the vortex condenser 10 is connected to a nitrogen pipe 38. The inlet of the nitrogen pipe 38 is connected to a pre-purge box 31 for supplying nitrogen. A first filter pressure reducing valve 37 is installed on the nitrogen pipe 38. The first pressure reducing valve 37 filters the nitrogen supplied in the pre-purge box 31 to prevent impurities in the gas in the pre-purge box 31 from entering the vortex condenser 10, while simultaneously reducing the nitrogen content in the pre-purge box. The pressure of the gas in chamber 31 is reduced so that the gas pressure entering the vortex condenser 10 is the same as the rated pressure of the vortex condenser 10. The sample gas outlet of the vortex condenser 10 is connected to a high-precision filter 11. The high-precision filter 11 intercepts ultrafine impurities that are not completely removed by the vortex condenser 10, providing clean sample gas for laser gas analyzer detection. The outlet of the high-precision filter 11 is connected to the laser gas analyzer 39. The condensate outlet of the vortex condenser 10 is connected to a peristaltic pump 12. The outlet of the peristaltic pump 12 is connected to a drain pipe 13. The drain pipe 13 passes through the wall of the laser analyzer protective box 20 and is connected to the waste liquid pool. The liquefied liquid settles in the vortex condenser 10 and is finally continuously discharged from the drain pipe 13 by the peristaltic pump 12, ensuring that the sample gas after treatment by the vortex condenser 10 is dry. The synergistic effect of the vortex condenser 10 and the high-precision filter 11 achieves efficient separation of impurities in the sample gas and improves the accuracy of mixed gas calorific value measurement.

[0025] The pre-purge box 31 includes a second nitrogen inlet pipe 40 connected to a nitrogen source. A nitrogen control valve 41 is installed on the second nitrogen inlet pipe 40. The outlet of the second nitrogen inlet pipe 40 branches into two branches. One branch connects to the inlet of the nitrogen pipe 38 to provide a cooling gas source for the scroll condenser 10. The other branch connects to a second filter pressure reducing valve 29. A pressure switch 23 is connected to the outlet of the second filter pressure reducing valve 29. An oil mist filter 24 is connected to the pressure output terminal of the pressure switch 23. The oil mist filter 24 filters the nitrogen. A second electromagnetic valve is installed at the outlet of the oil mist filter 24. Valve 28, the outlet of the second solenoid valve 28 is connected to the fifth solenoid valve 27, the third solenoid valve 25 and the fourth solenoid valve 26 respectively. The outlet of the fifth solenoid valve 27 is connected to the exhaust pipe 43. The outlet of the third solenoid valve 25 is connected to the backflush interface of the first external filter 6, the second external filter 5 and the third external filter 4 respectively. The outlet of the fourth solenoid valve 26 is connected to the self-regulating electric heat tracing cable 7. The self-regulating electric heat tracing cable 7 is equipped with a first solenoid valve 8. The connection point between the fourth solenoid valve 26 and the self-regulating electric heat tracing cable 7 is located at the input end of the first solenoid valve 8, which mainly controls the collection of sample gas.

[0026] The first sampling probe 1, the second sampling probe 2, and the third sampling probe 3 are located at the center, 1 / 3 of the radius, and 2 / 3 of the radius of the mixed gas pipeline 32, respectively. Because the mixed gas flows in the pipeline, the uniformity of the sample gas in the mixed gas pipeline 32 is inconsistent. The sample gas flow rate is the fastest and the composition is more uniform at the center of the mixed gas pipeline 32, while the sample gas flow rate is slower near the pipe wall of the mixed gas pipeline 32, and the sample gas is prone to stratification. By collecting sample gas from the center and both sides of the mixed gas pipeline 32 at the same time, the sampling probes can collect sample gas from different locations, making the collected sample gas more representative.

[0027] The insertion depth of the first sampling probe 1, the second sampling probe 2, and the third sampling probe 3 gradually decreases from the center of the pipe to both sides.

[0028] It also includes a PLC controller 30 installed inside the laser analyzer protective box 20. The control terminals of the PLC controller 30 are connected to the control terminals of the pressure switch 23, the first solenoid valve 8, the second solenoid valve 28, the third solenoid valve 25, the fourth solenoid valve 26, and the fifth solenoid valve 27 respectively after passing through the box wall of the laser analyzer protective box 20 via cable 21. The PLC controller 30 automatically controls the opening and closing of the pressure switch 23, the first solenoid valve 8, the second solenoid valve 28, the third solenoid valve 25, and the fourth solenoid valve 26 according to the internal program, so as to realize the automatic control of the start and stop of the backflushing process.

[0029] The laser gas analyzer 39 includes an external measuring gas chamber 15. The inlet of the external measuring gas chamber 15 is connected to the outlet of a high-precision filter 11. A laser emitting end 14 and a laser receiving end 16 are respectively arranged opposite to each other at both ends of the external measuring gas chamber 15. An exhaust pipe 17 is connected to the outlet of the external measuring gas chamber 15. The outlet of the exhaust pipe 17 passes through the wall of the laser analyzer protective box 20 and is connected to a pneumatic sampling pump 18. The inlet of the pneumatic sampling pump 18 is connected to a first nitrogen inlet pipe 19. The continuous negative pressure generated by the pneumatic sampling pump 18 promptly extracts the waste gas detected by the laser gas analyzer 39 and discharges it through the outlet of the pneumatic sampling pump 18, reducing the retention of sample gas in the laser gas analyzer 39.

[0030] A first through-hole ball valve 33 is installed between the first sampling probe 1 and the first external filter 6; a second through-hole ball valve 34 is installed between the second sampling probe 2 and the second external filter 5; and a third through-hole ball valve 35 is installed between the third sampling probe 3 and the third external filter 4. Each through-hole ball valve controls the opening and closing of each sampling branch. Opening a single through-hole ball valve enables single-point depth sampling, while opening two or three through-hole ball valves simultaneously enables multi-depth composite sampling. If a sampling probe is blocked, the through-hole ball valve can be closed, allowing for isolated cleaning of one sampling probe without shutting down the entire sampling system. The through-hole ball valves of other branches can be opened normally, ensuring the continuity of sample gas collection and avoiding detection interruptions due to maintenance of a single branch.

[0031] The pressure output terminal of the pressure switch 23 is also connected to an air storage tank 22, and the outlet of the air storage tank 22 is connected to a drain pipe 42, on which a shut-off valve 36 is installed.

[0032] When using it, the following steps are included: S1. Insert a first sampling probe 1, a second sampling probe 2, and a third sampling probe 3 with different depths into the dust separation hood at the outlet of the mixed gas pipeline 32. The insertion depth of the first sampling probe 1 is 1 / 3 of the radius of the mixed gas pipeline 32 and it is located at 1 / 3 of the radius of the mixed gas pipeline 32. The insertion depth of the second sampling probe 2 is the same as the radius of the mixed gas pipeline 32 and it is located at the center of the mixed gas pipeline 32. The insertion depth of the third sampling probe 3 is 2 / 3 of the radius of the mixed gas pipeline 32 and it is located at 2 / 3 of the radius of the mixed gas pipeline 32. S2. After sampling, the sample gas passes through the first external filter 6, the second external filter 5, and the third external filter 4 and then enters the self-regulating electric heating cable 7. The sample gas passing through the self-regulating electric heating cable 7 enters the vortex condenser 10. The liquid liquefied by the vortex condenser 10 settles in the vortex condenser 10 and is finally continuously discharged from the drain pipe 13 by the peristaltic pump 12. The sample gas passing through the vortex condenser 10 enters the high-precision filter 11. The clean sample gas filtered by the high-precision filter 11 enters the laser gas analyzer 39 for calorific value detection. S3. The exhaust gas after being detected by the laser gas analyzer 39 is promptly extracted by the continuous negative pressure generated by the pneumatic sampling pump 18 and discharged through the outlet of the pneumatic sampling pump 18. S4. PLC controller 30 controls the first solenoid valve 8 to close and end sampling. At the same time, PLC controller 30 controls the fifth solenoid valve 27 and the second solenoid valve 28 to open simultaneously, opening the nitrogen control valve 41. Nitrogen enters the second filter pressure reducing valve 29 in the pre-purge box 31 from the second nitrogen inlet pipe 40. The nitrogen then passes through the pressure switch 23, and finally passes through the second solenoid valve 28 and the fifth solenoid valve 27 in sequence before being discharged through the exhaust pipe 43, completing the purging of the interior of the pre-purge box 31. S5. After the purging of the pre-purging box 31 is completed, the PLC controller 30 controls the fifth solenoid valve 27 to close, keeps the second solenoid valve 28 open, and simultaneously opens the fourth solenoid valve 26 to enter the internal back-purging mode. At this time, the nitrogen gas passing through the second solenoid valve 28 passes through the fourth solenoid valve 26 and enters the self-regulating electric heat tracing cable 7 to purge the self-regulating electric heat tracing cable 7. The nitrogen gas passing through the self-regulating electric heat tracing cable 7 simultaneously passes through the sample gas outlets of the first external filter 6, the second external filter 5, and the third external filter 4 and enters the first external filter 6, the second external filter 5, and the third external filter 4 in reverse, respectively. Then, the nitrogen gas enters the first through-hole ball valve 33, the second through-hole ball valve 34, and the third through-hole ball valve 35, respectively. Finally, the nitrogen gas enters the first sampling probe 1, the second sampling probe 2, and the third sampling probe 35, respectively. The sampling probe 3 achieves internal back-purge of the sampling pipeline. By reverse-flowing nitrogen gas, the impact force of the nitrogen gas flow blows away impurities in the sample gas adhering to the self-regulating electric heating cable 7, the first external filter 6, the second external filter 5, the third external filter 4, the first through-hole ball valve 33, the second through-hole ball valve 34, the third through-hole ball valve 35, the first sampling probe 1, the second sampling probe 2, and the third sampling probe 3 from the original flow path, reducing blockage of the sampling pipeline and keeping the sampling pipeline unobstructed. After continuous purging for a period of time, the PLC controller 30 controls the fourth solenoid valve 26 to close, stopping the internal back-purge for a period of time. The above steps are repeated to achieve internal cyclic back-purge. After this step is repeated 4-7 times, the PLC controller 30 controls the fourth solenoid valve 26 to close, and the internal back-purge mode ends. S6. PLC controller 30 controls the opening of the third solenoid valve 25 to enter the external purging mode. At this time, nitrogen gas passing through the second solenoid valve 28 passes through the third solenoid valve 25, and then enters the backflush interface of the first external filter 6, the second external filter 5, and the third external filter 4 respectively to backflush the exterior of the first external filter 6, the second external filter 5, and the third external filter 4. The nitrogen gas is then discharged through the exhaust port of the external filter, realizing the internal backflush of the sampling channel. This blows away impurities outside the external filters from the original flow path, reducing the blockage of the sampling pipeline and keeping the sampling pipeline unobstructed. When the internal backflush ends, PLC controller 30 controls the closing of the third solenoid valve 25. After purging for a period of time, PLC controller 30 controls the closing of the third solenoid valve 25, stopping the external backflush for a period of time. Then, the above steps are repeated to realize the external cyclic backflush. After this step is repeated 4-7 times, PLC controller 30 controls the closing of the third solenoid valve 25, and the external backflush mode ends. S7. When sampling is required after backflushing is completed, the PLC controller 30 controls the second solenoid valve 28 to close. After the second solenoid valve 28 is closed, the first solenoid valve 8 is opened, and steps S1, S2, and S3 are repeated to sample the gas again.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A mixed gas calorific value online monitoring, sampling, and processing device, characterized in that: The system includes a mixed gas pipeline (32), the outlet of which is equipped with a dust separation hood. The dust separation hood is fitted with a first sampling probe (1), a second sampling probe (2), and a third sampling probe (3) at different depths. The sample gas outlets of the first sampling probe (1), the second sampling probe (2), and the third sampling probe (3) are respectively connected to a first external filter (6), a second external filter (5), and a third external filter (4). The sample gas outlets of the first external filter (6), the second external filter (5), and the third external filter (4) are combined and connected to a self-regulating electric heat tracing cable (7). The outlet of the self-regulating electric heat tracing cable (7) is connected to a laser analyzer assembly for monitoring the calorific value of the mixed gas.

2. The online monitoring and sampling device for the calorific value of mixed gas according to claim 1, characterized in that: The laser analyzer assembly includes a laser analyzer protective case (20), inside which a vortex condenser (10) and a laser gas analyzer (39) are installed. The outlet of the self-regulating electric heat tracing cable (7) passes through the wall of the laser analyzer protective case (20) and is connected to the inlet of the vortex condenser (10). The nitrogen inlet of the vortex condenser (10) is connected to a nitrogen pipe (38), and the inlet of the nitrogen pipe (38) is connected to a pre-blowing device for providing nitrogen. The first filter pressure reducing valve (37) is installed on the nitrogen pipe (38) of the scanning box (31). The sample gas outlet of the vortex condenser (10) is connected to a high-precision filter (11). The outlet of the high-precision filter (11) is connected to the laser gas analyzer (39). The condensate outlet of the vortex condenser (10) is connected to a peristaltic pump (12). The outlet of the peristaltic pump (12) is connected to a drain pipe (13). The drain pipe (13) passes through the wall of the laser analyzer protective box (20) and is connected to the waste liquid pool.

3. The online monitoring and sampling device for the calorific value of mixed coal gas according to claim 2, characterized in that: The pre-purge box (31) includes a second nitrogen inlet pipe (40) connected to a nitrogen source. A nitrogen control valve (41) is installed on the second nitrogen inlet pipe (40). The outlet of the second nitrogen inlet pipe (40) is divided into two branches. One branch is connected to the inlet of the nitrogen pipe (38). The other branch is connected to a second filter pressure reducing valve (29). A pressure switch (23) is connected to the outlet of the second filter pressure reducing valve (29). An oil mist filter (24) is connected to the pressure output end of the pressure switch (23). A first oil mist filter (24) is installed at the outlet of the oil mist filter (24). Two solenoid valves (28) are connected to the outlets of the second solenoid valve (28), the fifth solenoid valve (27), the third solenoid valve (25), and the fourth solenoid valve (26). The outlet of the fifth solenoid valve (27) is connected to the exhaust pipe (43). The outlet of the third solenoid valve (25) is connected to the backflush ports of the first external filter (6), the second external filter (5), and the third external filter (4). The outlet of the fourth solenoid valve (26) is connected to the self-regulating electric heat tracing cable (7). The self-regulating electric heat tracing cable (7) is equipped with the first solenoid valve (8).

4. The online monitoring and sampling device for the calorific value of mixed gas according to claim 3, characterized in that: The first sampling probe (1), the second sampling probe (2) and the third sampling probe (3) are located at the center, 1 / 3 and 2 / 3 of the radius of the mixed gas pipeline (32), respectively.

5. The online monitoring and sampling device for the calorific value of mixed gas according to claim 4, characterized in that: The insertion depth of the first sampling probe (1), the second sampling probe (2), and the third sampling probe (3) gradually decreases from the center of the pipe to both sides.

6. The online monitoring and sampling device for the calorific value of mixed gas according to claim 5, characterized in that: It also includes a PLC controller (30) installed in the protective box (20) of the laser analyzer. The control terminal of the PLC controller (30) is connected to the control terminals of the pressure switch (23), the first solenoid valve (8), the second solenoid valve (28), the third solenoid valve (25), the fourth solenoid valve (26), and the fifth solenoid valve (27) respectively after passing through the box wall of the protective box (20) via a cable (21).

7. The online monitoring and sampling device for the calorific value of mixed gas according to claim 6, characterized in that: The laser gas analyzer (39) includes an external measuring gas chamber (15). The inlet of the external measuring gas chamber (15) is connected to the outlet of a high-precision filter (11). The two ends of the external measuring gas chamber (15) are respectively provided with a laser emitting end (14) and a laser receiving end (16) arranged opposite to each other. The outlet of the external measuring gas chamber (15) is connected to an exhaust pipe (17). The outlet of the exhaust pipe (17) passes through the wall of the laser analyzer protective box (20) and is connected to a pneumatic sampling pump (18). The inlet of the pneumatic sampling pump (18) is connected to a first nitrogen inlet pipe (19).

8. A mixed gas calorific value online monitoring and sampling processing device according to claim 7, characterized in that: A first through-hole ball valve (33) is installed between the first sampling probe (1) and the first external filter (6), a second through-hole ball valve (34) is installed between the second sampling probe (2) and the second external filter (5), and a third through-hole ball valve (35) is installed between the third sampling probe (3) and the third external filter (4).

9. The online monitoring and sampling device for the calorific value of mixed gas according to claim 8, characterized in that: The pressure output terminal of the pressure switch (23) is also connected to a gas storage tank (22), and the outlet of the gas storage tank (22) is connected to a drain pipe (42), and a shut-off valve (36) is installed on the drain pipe (42).

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