Constant temperature extraction detection system and detection method for high temperature and high dust gas

Abstract

The invention discloses a constant temperature extraction detection system for high temperature and high dust gas, comprising: a differential pressure cyclone dust sampler connected to a process pipeline, a primary filter is arranged on the differential pressure cyclone dust sampler, the primary filter is located in a first heating box, a first gas pipeline is connected to the primary filter, the first gas pipeline extends into a second heating box and is connected to a fine filter and a first ball valve, a heating cable is wound around the first gas pipeline, the first gas pipeline is connected to the second gas pipeline, a sampling pump is arranged on the second gas pipeline, a heating cable is wound around the second gas pipeline, the second gas pipeline is connected to a composite laser measuring tube in an analysis cabinet, the composite laser measuring tube is located in a third heating box, and the composite laser measuring tube is connected to a pressure stabilizing discharge device through the third gas pipeline. The advantage of the invention is that it can perform high-precision measurement and analysis of high-temperature sample gas at a constant high temperature.

Description

Technical Field

[0001] The present invention relates to the field of sample gas analysis, and in particular to a constant temperature extraction detection system and a detection method thereof for high temperature and high dust gas. Background Art

[0002] The analytical instruments used in the current sample gas analysis system need to strictly control the temperature, cleanliness, dryness, etc. of the sample gas, so the high-temperature, high-dust sample gas must be cooled, filtered, dehumidified, and dried before detection. When performing the above-mentioned treatments, cooling, filtering, water washing, condensation and dehumidification equipment will be used in the pretreatment unit of the analysis system for purification and condensation and dehumidification. A small amount of ammonia, sulfur dioxide, hydrogen sulfide and other water-soluble media that need to be measured in the sample gas will be removed along with the condensation and dehumidification of the sample gas, and thus cannot be measured and analyzed. If only dust removal is performed and the sample gas is measured and analyzed at a high temperature, once the high-temperature sample gas enters the analyzer in the analysis system, the sensor in the analyzer will be damaged, and the high-temperature sample gas cannot be detected.

[0003] The purpose of the present invention is to provide a constant temperature extraction detection system and detection method for high temperature and high dust gas, which can keep the sample gas at a constant high temperature during the sampling, dust removal and detection process, so that the components in the sample gas can be accurately and reliably measured and analyzed without changing the physical properties and component content, thereby ensuring the authenticity and accuracy of the measurement and analysis results.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a constant temperature extraction and detection system for high-temperature and high-dust gas, comprising: a differential pressure cyclone dust sampler connected to a process pipeline, a first heating box is arranged on the differential pressure cyclone dust sampler, a primary filter is arranged on the differential pressure cyclone dust sampler, the primary filter is located in the first heating box, a first gas pipe is connected to the primary filter, the first gas pipe extends into the second heating box, a heating cable is wound around the first gas pipe, a fine filter and a first ball valve are arranged in sequence on the first gas pipe located in the second heating box, the first gas pipe is connected to the second gas pipe, a sampling pump is arranged on the second gas pipe, a heating cable is wound around the second gas pipe, the second gas pipe is connected to a composite laser measuring tube in an analysis cabinet, the composite laser measuring tube is located in a third heating box, a third gas pipe is connected to the composite laser measuring tube, and the third gas pipe is connected to a pressure-stabilizing discharge device after extending out of the third heating box;

[0005] The differential pressure cyclone dust removal sampler comprises: a positive pressure guide pipe, a negative pressure guide pipe, and a sample gas pipe, wherein grooves are provided at the lower ends of the positive pressure guide pipe and the negative pressure guide pipe, a plurality of external air inlet holes are provided on the negative pressure guide pipe, a spiral disk is spirally provided on the sample gas pipe, a plurality of internal air inlet holes are provided on the sample gas pipe provided with the spiral disk, the positive pressure guide pipe is sealed and fixed on the process pipeline, the groove in the positive pressure guide pipe faces the windward direction in the process pipeline, the negative pressure guide pipe is sealed and arranged in the positive pressure guide pipe and an air inlet gap is left between the positive pressure guide pipe and the sample gas pipe, the groove in the negative pressure guide pipe faces the downwind direction in the process pipeline and extends downward from the positive pressure guide pipe, the sample gas pipe is sealed and arranged in the negative pressure guide pipe and an exhaust gap is left between the negative pressure guide pipe and the sample gas pipe, the spiral disk is located in the exhaust gap, the external air inlet hole on the negative pressure guide pipe is located above the spiral disk of the sample gas pipe, and the primary filter is connected to the sample gas pipe;

[0006] The composite laser measuring tube comprises: an inner tube and an outer tube, a gas distributor is sealed between the two outer tubes, a mounting hole and a reflux hole are arranged on the gas distributor, a sample gas inlet connected to the mounting hole is arranged on the gas distributor, a second gas delivery pipe is connected to the sample gas inlet, a sample gas outlet connected to the reflux hole is arranged on the gas distributor, and a third gas delivery pipe is connected to the sample gas outlet. The inner tube sealing card is arranged in the mounting hole, the length of the inner tube is the effective measuring optical path of the laser analyzer, an inner through hole connected to the sample gas inlet is arranged on the inner tube, a heating plate is arranged on one end of the two outer tubes away from the gas distributor, a transmitting unit of the laser analyzer and a receiving unit of the laser analyzer are respectively arranged on one end of the two outer tubes provided with the heating plate, a nitrogen purge hole is arranged on the transmitting unit of the laser analyzer and the receiving unit of the laser analyzer, and the nitrogen purge hole is connected to a nitrogen gas source through a nitrogen pipe.

[0007] Furthermore, the aforementioned constant temperature extraction and detection system for high-temperature and high-dust gases, wherein a sealing cover is provided in the first heating box, a primary filter is provided in the sealing cover, the sample gas pipe in the differential pressure cyclone dust sampler passes through the first heating box and the sealing cover in sequence and is connected to the primary filter, a first recoil pipe is connected to the sealing cover, a second recoil pipe is connected to the first air supply pipe located in the second heating box, and both the first recoil pipe and the second recoil pipe are connected to the nitrogen gas source after passing through the second heating box.

[0008] Furthermore, in the aforementioned constant temperature extraction and detection system for high-temperature and high-dust gases, a thermal insulation jacket is provided on the sample gas pipe, the lower end of the thermal insulation jacket extends into the negative pressure guide tube and is sealedly connected to the negative pressure guide tube, and the upper end of the thermal insulation jacket passes through the first heating box and is sealedly connected to the sealing cover.

[0009] Furthermore, in the aforementioned constant temperature extraction and detection system for high temperature and high dust gas, two differential pressure cyclone dust samplers are arranged on the process pipeline, and the first air pipes on the two differential pressure cyclone dust samplers are connected to the same second air pipe.

[0010] Furthermore, in the aforementioned constant temperature extraction detection system for high-temperature, high-dust gas, a second ball valve is provided on the second gas supply pipe, a detection tube is connected to the second gas supply pipe located between the second ball valve and the composite laser measuring tube, a three-way valve is provided on the detection tube, one end of the three-way valve is connected to the zero gas source through the first branch pipe, and the other end of the three-way valve is connected to the standard gas source through the second branch pipe.

[0011] Furthermore, in the aforementioned constant temperature extraction and detection system for high-temperature and high-dust gas, the two outer tubes are respectively connected to the emitting unit of the laser analyzer and the receiving unit of the laser analyzer through a reducing short section, and the reducing short section is sealed and fixed on the side wall of the third heating box, and the emitting unit of the laser analyzer and the receiving unit of the laser analyzer are both located on the outside of the third heating box.

[0012] The detection method described above uses the above-mentioned constant temperature extraction detection system for high temperature and high dust gas, and its steps are as follows:

[0013] S1. Start the first heating box, the second heating box, the third heating box and the heating cable, then open the first ball valve and the sampling pump. When the high-temperature gas in the process pipeline encounters the groove of the positive pressure guide pipe, it will move upward along the air intake gap, and then enter the exhaust gap from the outer air intake hole on the negative pressure guide pipe. The groove of the negative pressure guide pipe generates negative pressure due to air flow separation. The high-temperature gas entering the exhaust gap will flow downward under the action of negative pressure. The high-temperature gas will rotate at high speed under the guidance of the spiral disk. Under the centrifugal effect, the high-temperature gas will be stratified, and the high pressure gas near the sample gas pipe will be separated. The high-temperature gas is relatively clean, and there are large particles of dust in the high-temperature gas far away from the sample gas pipe. When the stratified high-temperature gas meets the inner air inlet downward, the high-temperature gas close to the sample gas pipe will enter the sample gas pipe under the action of the suction pressure of the sampling pump, and move toward the first gas pipeline as the high-temperature sample gas, while the large particles of dust will continue to move downward under the action of negative pressure with the high-temperature gas far away from the sample gas pipe until it falls back into the process pipeline. The high-temperature sample gas in the sample gas pipe enters the first gas pipeline after coarse filtration by the primary filter, and then enters the fine filter for fine filtration;

[0014] S2. The nitrogen purge holes on the transmitting unit and the receiving unit of the laser analyzer are sprayed at the same time. The high-temperature sample gas that has been finely filtered first enters the inner tube through the gas distributor. The high-temperature sample gas gathers in the inner tube and gradually squeezes the nitrogen into the outer tube. When the inner tube is full of the high-temperature sample gas, the excess high-temperature sample gas diffuses into the outer tube and mixes with the nitrogen at both ends of the inner tube. The nitrogen is sealed at both ends of the inner tube. The transmitting unit and the receiving unit of the laser analyzer measure and analyze the high-temperature sample gas in the inner tube, thereby obtaining the concentration of each component in the high-temperature sample gas.

[0015] S3. Nitrogen and high-temperature sample gas are mixed and flow back into the outer tube together and flow into the third gas pipeline through the reflux hole in the gas distributor. The third gas pipeline transports the mixed gas of nitrogen and high-temperature sample gas to the pressure-stabilizing discharge device for water washing and then discharges it.

[0016] Furthermore, in the detection method, in S1, the heating temperature of the first heating box and the heating cable is 110-115°C, and the heating temperature of the second heating box and the third heating box is 120-125°C.

[0017] Furthermore, in the detection method, in S1, the suction pressure of the sampling pump is greater than the gas pressure in the process pipeline, and in S2, the suction pressure of the sampling pump is greater than the pressure of the nitrogen blown out from the nitrogen purge holes in the transmitting unit of the laser analyzer and the receiving unit of the laser analyzer.

[0018] The advantages of the present invention are as follows: the differential pressure cyclone dust sampler can sample the high temperature gas in the process pipeline by using the pressure difference, and after sampling, the pressure difference can be used to centrifugally remove the high temperature gas, thereby removing most of the large dust particles in the high temperature gas, thereby obtaining a high temperature sample gas containing small dust particles, and then the high temperature sample gas obtained by the differential pressure cyclone dust sampler can be double filtered by a primary filter and a fine filter to obtain a clean high temperature sample gas, which can extend the service life of the primary filter, and then the high temperature sample gas enters the composite laser measuring tube for measurement and analysis, the composite laser measuring tube uses a laser of a specific wavelength to interact with the gas molecules in the high temperature sample gas, and determines the components in the high temperature sample gas by analyzing the intensity change or scattered light characteristics after the laser passes through the gas. and the concentration of each component, with high measurement efficiency and measurement accuracy. During the entire transportation and measurement process, the high-temperature sample gas is completed under high constant temperature conditions, and the high-temperature sample gas will not condense. There will be no condensed water affecting the measurement accuracy of the composite laser measuring tube, and there will be no dissolution of components in the high-temperature sample gas and condensed water. The high-temperature sample gas completes the measurement work without changes in physical properties and content, ensuring the measurement accuracy, and is finally discharged through a pressure-stabilizing discharge device. The pressure-stabilizing discharge device can not only play a pressure-stabilizing role, offset the pressure fluctuations in the process pipeline, and prevent the pressure fluctuations in the process pipeline from affecting the measurement accuracy of the composite laser measuring tube, but also dissolve the harmful components in the high-temperature sample gas that are easily soluble in water in water, so that the high-temperature sample gas meets the emission standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the constant temperature extraction and detection system for high temperature and high dust gas described in the present invention.

[0020] Figure 2 yes Figure 1 Schematic diagram of the structure of a medium differential pressure cyclone dust sampler.

[0021] Figure 3 yes Figure 1 Schematic diagram of the structure of the composite laser measuring tube.

[0022] Figure 4 yes Figure 3 Schematic diagram of the structure of the gas distributor. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and preferred embodiments.

[0024] like Figure 1 to Figure 4As shown, the constant temperature extraction detection system for high-temperature and high-dust gas described in the present invention comprises: a differential pressure cyclone dust sampler 2 connected to a process pipeline 1, two differential pressure cyclone dust samplers 2 are arranged on the process pipeline 1, a first heating box 11 is arranged on the differential pressure cyclone dust sampler 2, a sealing cover 111 is arranged in the first heating box 11, a first recoil pipe 112 is connected to the sealing cover 111, the first recoil pipe 112 passes through the second heating box 12 and is connected to a nitrogen gas source, a primary filter 21 is arranged on the differential pressure cyclone dust sampler 2, the primary filter 21 is located in the sealing cover 111, a first gas pipe 3 is connected to the primary filter 21, a heating cable is wound around the first gas pipe 3 and the first recoil pipe 112, and the first gas pipe 3 extends into the second heating box 12, A second recoil pipe 31 is connected to the first gas pipe 3 located in the second heating box 12. The second recoil pipe 31 is connected to a nitrogen gas source after passing through the second heating box 12. A heating cable is also wound around the second recoil pipe 31. A fine filter 32 and a first ball valve 33 are sequentially arranged on the first gas pipe 3 located in the second heating box 12. The two first gas pipes 3 are connected to the same second gas pipe 4. A sampling pump 41 is arranged on the second gas pipe 4. A heating cable is wound around the second gas pipe 4. The second gas pipe 4 is connected to a composite laser measuring tube 5 in the analysis cabinet. The composite laser measuring tube 5 is located in the third heating box 13. A third gas pipe 6 is connected to the sample gas outlet of the composite laser measuring tube 5. The third gas pipe 6 is connected to a pressure stabilizing discharge device 7 after extending out of the third heating box 13.

[0025] Open the first ball valve 33 on any one of the first gas pipelines 3, so that the differential pressure cyclone dust sampler 2 connected to the first gas pipeline 3 samples and centrifugally filters the high-temperature gas in the process pipeline 1. The suction pressure generated by the sampling pump 41 acts on the high-temperature sample gas in the differential pressure cyclone dust sampler 2. The high-temperature sample gas enters the first gas pipeline 3 after the primary filtration of the primary filter 21, and then enters the second gas pipeline 4 under the fine filtration of the fine filter 32, and then enters the composite laser measuring tube 5 for measurement and analysis, completing the measurement and analysis. Afterwards, the high-temperature sample gas enters the pressure-stabilizing discharge device 7 through the third gas pipeline 6, is washed with water, and then discharged outward. The pressure-stabilizing discharge device 7 in this embodiment selects the integrated gas pressure-stabilizing discharge device with the publication number: CN221648219U. The pressure-stabilizing discharge device 7 can not only play a pressure-stabilizing role, offset the air pressure fluctuation in the process pipeline 1, and prevent the air pressure fluctuation generated in the process pipeline 1 from affecting the measurement accuracy of the composite laser measuring tube 5, but also dissolve the harmful components in the high-temperature sample gas that are easily soluble in water in water, so that the high-temperature sample gas meets the emission standards. During the whole process, it is necessary to heat the first heating box 11 and the heating cable to 110-115°C, and heat the second heating box 12 and the third heating box 13 to 120-125°C. This can ensure that the high-temperature sample gas will not condense during the entire transportation, filtration, measurement and analysis process, and can prevent the water-soluble medium in the high-temperature sample gas from dissolving into the condensed water, thereby reducing the subsequent detection deviation of the high-temperature sample gas. When the primary filter 21 or the first air supply pipe 3 on the sampling differential pressure cyclone dust sampler 2 is blocked, open the first ball valve 33 on the other first air supply pipe 3 to allow the other differential pressure cyclone dust sampler 2 to sample, and open the first ball valve 33 on the first air supply pipe 3 connected to the blocked differential pressure cyclone dust sampler 2. The ball valve 33 is closed, and the second recoil pipe 31 is opened first to transport the nitrogen in the nitrogen source to the second recoil pipe 31, and then the nitrogen is transported to the sealing cover 111 through the second recoil pipe 31 to recoil the primary filter 21, so that the dust on the surface of the primary filter 21 is blown into the differential pressure cyclone dust sampler 2, and then falls into the process pipeline 1, and then the second recoil pipe 31 is closed, and the first recoil pipe 112 is opened. The nitrogen passes through the first recoil pipe 112 to recoil the primary filter 21. During the recoil process, the heating cables on the first recoil pipe 112 and the second recoil pipe 31 remain heated to prevent condensation from occurring during the recoil process, which may cause condensed water to appear in the first gas pipe 3 and the differential pressure cyclone dust sampler 2.

[0026] In the present embodiment, the differential pressure cyclone dust sampler 2 comprises: a positive pressure flow guide tube 22, a negative pressure flow guide tube 23, and a sample gas tube 24. Bevels are provided at the lower ends of the positive pressure flow guide tube 22 and the negative pressure flow guide tube 23, a plurality of external air inlet holes 231 are provided on the negative pressure flow guide tube 23, a spiral disk 241 is spirally provided on the sample gas tube 24, and a plurality of internal air inlet holes 242 are provided on the sample gas tube 24 provided with the spiral disk 241. The positive pressure flow guide tube 22 is sealed and fixed on the process pipeline 1, and the bevel in the positive pressure flow guide tube 22 faces the windward direction in the process pipeline 1, and the negative pressure flow guide tube 23 is sealed and arranged in the positive pressure flow guide tube 22 and an air inlet gap is left between the positive pressure flow guide tube 22 and the negative pressure flow guide tube 23. The groove in the guide pipe 23 faces the downwind direction in the process pipeline 1 and extends downward from the positive pressure guide pipe 22. The sample gas pipe 24 is sealed in the negative pressure guide pipe 23 and an exhaust gap is left between the sample gas pipe 24 and the negative pressure guide pipe 23. The spiral disk 241 is located in the exhaust gap. The external air inlet 231 on the negative pressure guide pipe 23 is located above the spiral disk 241 of the sample gas pipe 24. The primary filter 21 is connected to the air outlet end of the sample gas pipe 24. A thermal insulation jacket 25 is provided on the air outlet end of the sample gas pipe 24. The lower end of the thermal insulation jacket 25 extends into the negative pressure guide pipe 23 and is sealed with the negative pressure guide pipe 23. The upper end of the thermal insulation jacket 25 passes through the first heating box 11 and is sealed with the sealing cover 111.

[0027] When the high-temperature gas in the process pipeline 1 hits the front of the bevel in the positive pressure guide pipe 22 in the windward direction during flow, a positive pressure area will be formed at the bevel in the windward direction of the positive pressure guide pipe 22. At this time, the high-temperature gas in the process pipeline 1 will move upward along the air intake gap under the action of the positive pressure, and then enter the exhaust gap from the outer air intake hole 231 on the negative pressure guide pipe 23. Since the bevel of the negative pressure guide pipe 23 is facing the downwind direction of the process pipeline 1, the high-temperature gas in the process pipeline 1 will be The back of the groove blocks the airflow and causes it to separate, so that the gas pressure on the front of the groove of the negative pressure guide pipe 23 is reduced, so that the groove of the negative pressure guide pipe 23 is in a negative pressure state, and the high-temperature gas entering the exhaust gap will flow downward under the action of the negative pressure. When the high-temperature gas flows downward, it will rotate at a high speed under the guidance of the spiral disk 241. The larger dust particles in the high-temperature gas have a larger weight and are subjected to a larger centrifugal force, so they will rotate to the outer circle of the airflow, while the dust with smaller particle size will remain in the inner circle of the airflow, forming small particles in the inner circle in the high-temperature gas. The distribution of large dust particles in the outer circle, the larger dust particles will fall into the gap between the spiral disk 241 and the negative pressure guide tube 23, and flow downward with the spiral descending airflow until they fall into the process pipeline 1, and the relatively clean inner circle high-temperature gas close to the sample gas pipe 24 will enter the sample gas pipe 24 through the inner air inlet 242 under the suction pressure of the sampling pump 41, and move toward the first gas pipeline 3 as a high-temperature sample gas. In this embodiment, the suction pressure of the sampling pump 41 is greater than the negative pressure generated by the negative pressure guide tube 23. In this way, the high-temperature gas located at the center of the sample gas pipe 24 can be extracted through the inner air inlet hole 242. However, the suction pressure of the sampling pump 41 and the negative pressure generated by the negative pressure guide tube 23 will offset each other at the bottom of the sample gas pipe 24, so as not to destroy the negative pressure state in the negative pressure guide tube 23, so that the high-temperature sample gas and large particles of dust far away from the sample gas pipe 24 can fall into the process pipeline 1 under the action of negative pressure. The suction pressure of the sampling pump 41 is greater than the gas pressure in the process pipeline 1. The specific suction pressure of the sampling pump 41 is obtained after multiple adjustments.

[0028] In this embodiment, the composite laser measuring tube 5 comprises: an inner tube 51 and an outer tube 52, a gas distributor 53 is sealed between the two outer tubes 52, a mounting hole 531 and a reflux hole 532 are provided on the gas distributor 53, a sample gas inlet 533 connected to the mounting hole 531 is provided on the gas distributor 53, a second gas delivery pipe 4 is connected to the sample gas inlet 533, a sample gas outlet 534 connected to the reflux hole 532 is provided on the gas distributor 53, a third gas delivery pipe 6 is connected to the sample gas outlet 534, the inner tube 51 is sealed and clamped in the mounting hole 531, the length of the inner tube 51 is the effective measurement optical path of the laser analyzer, and a sample gas outlet 534 connected to the sample gas inlet 533 is provided on the inner tube 51. The inner through hole connected to the gas inlet 533 is provided with a heating plate 54 on one end of the two outer tubes 52 away from the gas distributor 53. The ends of the two outer tubes 52 provided with the heating plate 54 are respectively connected to the emitting unit 56 of the laser analyzer and the receiving unit 57 of the laser analyzer through a reducing short section 55. The reducing short section 55 is sealed and fixed on the side wall of the third heating box 13. The emitting unit 56 of the laser analyzer and the receiving unit 57 of the laser analyzer are both located on the outside of the third heating box 13. Nitrogen purge holes 58 are provided on the emitting unit 56 of the laser analyzer and the receiving unit 57 of the laser analyzer. The nitrogen purge holes 58 are connected to the nitrogen gas source through a nitrogen pipe.

[0029] The nitrogen purge holes 58 on the transmitting unit 56 of the laser analyzer and the receiving unit 57 of the laser analyzer will spray nitrogen toward the inner tube 51. The pressure of the nitrogen sprayed out of the nitrogen purge holes is less than the suction pressure of the sampling pump 41, so that the inner tube 51 is filled with nitrogen. Then, the filtered high-temperature sample gas is transported from the second gas transmission pipe 4 to the sample gas inlet 533 of the gas distributor 53, and then enters the inner tube 51 through the inner through hole on the inner tube 51. Since the pressure of the high-temperature sample gas is greater than the blowing pressure of the nitrogen, the high-temperature sample gas will gradually squeeze the nitrogen out of the inner tube 51 until only the high-temperature sample gas exists in the inner tube 51. When the inner tube 51 is filled with the high-temperature sample gas, the excess high-temperature sample gas will flow out from both ends of the inner tube 51 and enter the outer tube 52 for diffusion, and the sample gas located in the outer tube 52 will be discharged from the inner tube 51. The pressure of the high-temperature sample gas will be reduced, thereby offsetting the pressure of the nitrogen gas. The nitrogen gas and the high-temperature sample gas will be sealed at the end of the inner tube 51. The emitting unit 56 of the laser analyzer and the receiving unit 57 of the laser analyzer can only measure and analyze the high-temperature sample gas in the inner tube 51, thereby obtaining the concentration of each component in the high-temperature sample gas. The nitrogen injection not only plays a sealing role, but also prevents the high-temperature sample gas from entering the emitting unit 56 of the laser analyzer and the receiving unit 57 of the laser analyzer to cause damage to the emitting unit 56 or the receiving unit 57. The nitrogen gas and the high-temperature sample gas entering the outer tube 52 will be mixed and will enter the reflux hole 532 of the gas distributor 53 and then flow from the sample gas outlet 534 into the third gas pipeline 6, and finally enter the pressure-stabilizing discharge device 7 for water washing and discharge. When the nitrogen gas is purged and sealed, the temperature difference between the nitrogen gas and the high-temperature sample gas will be reduced after being heated by the heating plate 54 to prevent condensation.

[0030] When the transmitting unit 56 of the laser analyzer and the receiving unit 57 of the laser analyzer cooperate to measure and analyze the high-temperature sample gas in the inner tube 51, a measurement error will be caused by the mixing of nitrogen at both ends of the inner tube 51. In order to solve this measurement error, a second ball valve 42 is arranged on the second gas supply pipe 4, and a detection tube 43 is connected to the second gas supply pipe 4 between the second ball valve 42 and the composite laser measuring tube 5. A three-way valve 431 is arranged on the detection tube 43. One end of the three-way valve 431 is connected to a zero-point gas source through a first branch pipe. The zero-point gas in the zero-point gas source refers to a basic gas of high-purity nitrogen or clean air that does not contain the component to be measured. The other end of the three-way valve 431 is connected to a standard gas source through a second branch pipe. The standard gas in the standard gas source refers to a mixed gas with known components and concentrations of each component. In this embodiment, the composition of the standard gas is the same as that of the high-temperature sample gas to be measured, and the concentration of each component is a self-prepared concentration.

[0031] Before the formal measurement and analysis, the second ball valve 42 is closed first, the zero gas source is opened, and then the zero gas is transported to the composite laser measuring tube 5 through the second gas pipe 4 to remove the residual gas in the composite laser measuring tube 5. During this process, the transmitting unit 56 and the receiving unit 57 of the laser analyzer continue to work, and the nitrogen purge hole does not spray nitrogen. When the laser analyzer does not find any component to be measured in the inner tube 51, it means that the composite laser measuring tube 5 is full of zero gas. Then switch the three-way valve 431, open the standard gas source, and the standard gas enters the composite laser measuring tube 5 to completely replace the original zero gas. The delivery pressure of the standard gas is the same as that of the component to be measured. The delivery pressure of the measured high-temperature sample gas remains consistent. At the same time, nitrogen is sprayed in the nitrogen purge hole. The transmitting unit 56 of the laser analyzer and the receiving unit 57 of the laser analyzer measure and analyze the standard gas in the inner tube 51 to obtain the measured concentration of each component in the standard gas. At this time, due to the influence of nitrogen, the measured concentration of each component in the standard gas is lower than the self-prepared concentration of each component in the standard gas. There will be a difference between the measured concentration of each component and the self-prepared concentration, and this difference is the measurement error. When the high-temperature sample gas is measured and analyzed later, the laser analyzer will automatically combine the measured concentration of each component with the corresponding difference to obtain the self-prepared concentration of each component in the high-temperature sample gas.

[0032] The detection method of the constant temperature extraction detection system for high temperature and high dust gas described in the present invention comprises the following steps:

[0033] S1. Close the second ball valve 42 on the second gas supply pipe 4, pass the zero-point gas into the composite laser measuring tube 5, remove the residual gas in the composite laser measuring tube 5, and then pass the standard gas into the composite laser measuring tube 5. The nitrogen purge holes on the emitting unit 56 and the receiving unit 57 of the laser analyzer are sprayed at the same time. Then, the measured concentration of each component in the standard gas is compared with the self-prepared concentration of each component in the standard gas. The difference between the two is the measurement error, and the laser analyzer records the measurement error.

[0034] S2, start the first heating box 11, the second heating box 12, the third heating box 13 and the heating cable, the temperature of the first heating box 11 and the heating cable is controlled at 110-115°C, the temperature of the second heating box 12 and the third heating box 13 is controlled at 120-125°C, then open the first ball valve 33 and the sampling pump 41 on any first gas pipeline 3, the suction pressure of the sampling pump 41 is consistent with the delivery pressure of the standard gas in S1, and the suction pressure of the sampling pump 41 is greater than the gas pressure in the process pipeline 1, the high-temperature gas close to the inner air inlet 242 on the sample gas pipe 24 can overcome the negative pressure and be sucked into the sample gas pipe 24, the high-temperature gas in the process pipeline 1 is collected and filtered by the differential pressure cyclone dust removal sampler 2 to form a high-temperature sample gas, the high-temperature sample gas enters the primary filter 21 for coarse filtration under the extraction action of the sampling pump 41, and then enters the fine filter 32 on the first gas pipeline 3 for fine filtration;

[0035] During this process, if the primary filter 21 or the first air pipe 3 on the differential pressure cyclone dust sampler 2 for sampling is blocked, open the first ball valve 33 on the other first air pipe 3 to allow the other differential pressure cyclone dust sampler 2 to sample, close the first ball valve 33 on the first air pipe 3 connected to the blocked differential pressure cyclone dust sampler 2, open the second recoil pipe 31 first, transport the nitrogen in the nitrogen source to the second recoil pipe 31, and transport the nitrogen to the sealing cover 111 through the second recoil pipe 31 to recoil the primary filter 21, so that the dust on the surface of the primary filter 21 is blown into the sample gas pipe 24, and then close the second recoil pipe 31, open the first recoil pipe 112, and the nitrogen passes through the first recoil pipe 112 to recoil the primary filter 21 and the sample gas pipe 24, and blows the dust accumulated in the sample gas pipe 24 into the process pipeline 1.

[0036] S3, the high-temperature sample gas after fine filtration enters the second gas pipeline 4, and then enters the composite laser measuring tube 5. The nitrogen purge holes on the emitting unit 56 and the receiving unit 57 of the laser analyzer are sprayed at the same time. The pressure of the nitrogen sprayed out of the nitrogen purge hole is less than the suction pressure of the sampling pump 41 in S2, so that the high-temperature sample gas and the nitrogen can be mixed at the outer end of the inner tube 51, which will not affect the measurement effect. The laser analyzer will measure the concentration of each component in the high-temperature sample gas and combine it with the measurement error of each component obtained in S1 to obtain the actual concentration of each measured component in the high-temperature sample gas.

[0037] S4. The nitrogen and high-temperature sample gas are mixed and flow back into the outer tube 52 together and flow into the third gas pipeline 6 through the reflux hole 532 and the sample gas outlet 534 in the gas distributor 53. The third gas pipeline 6 transports the mixed gas of nitrogen and high-temperature sample gas to the pressure-stabilizing discharge device 7 for water washing and then discharges it.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. Constant temperature extraction and detection system for high temperature and high dust gas, characterized by: include: A differential pressure cyclone dust sampler connected to a process pipeline, a first heating box is provided on the differential pressure cyclone dust sampler, a primary filter is provided on the differential pressure cyclone dust sampler, the primary filter is located in the first heating box, a first air pipe is connected to the primary filter, the first air pipe extends into the second heating box, a heating cable is wound around the first air pipe, a fine filter and a first ball valve are sequentially provided on the first air pipe located in the second heating box, the first air pipe is connected to the second air pipe, a sampling pump is provided on the second air pipe, a heating cable is wound around the second air pipe, the second air pipe is connected to a composite laser measuring tube in an analysis cabinet, the composite laser measuring tube is located in a third heating box, a third air pipe is connected to the composite laser measuring tube, and the third air pipe is connected to a pressure-stabilizing discharge device after extending out of the third heating box; The differential pressure cyclone dust removal sampler comprises: a positive pressure guide pipe, a negative pressure guide pipe, and a sample gas pipe, wherein grooves are provided at the lower ends of the positive pressure guide pipe and the negative pressure guide pipe, a plurality of external air inlet holes are provided on the negative pressure guide pipe, a spiral disk is spirally provided on the sample gas pipe, a plurality of internal air inlet holes are provided on the sample gas pipe provided with the spiral disk, the positive pressure guide pipe is sealed and fixed on the process pipeline, the groove in the positive pressure guide pipe faces the windward direction in the process pipeline, the negative pressure guide pipe is sealed and arranged in the positive pressure guide pipe and an air inlet gap is left between the positive pressure guide pipe and the sample gas pipe, the groove in the negative pressure guide pipe faces the downwind direction in the process pipeline and extends downward from the positive pressure guide pipe, the sample gas pipe is sealed and arranged in the negative pressure guide pipe and an exhaust gap is left between the negative pressure guide pipe and the sample gas pipe, the spiral disk is located in the exhaust gap, the external air inlet hole on the negative pressure guide pipe is located above the spiral disk of the sample gas pipe, and the primary filter is connected to the sample gas pipe; The composite laser measuring tube comprises: an inner tube and an outer tube, a gas distributor is sealed between the two outer tubes, a mounting hole and a reflux hole are arranged on the gas distributor, a sample gas inlet connected to the mounting hole is arranged on the gas distributor, a second gas delivery pipe is connected to the sample gas inlet, a sample gas outlet connected to the reflux hole is arranged on the gas distributor, and a third gas delivery pipe is connected to the sample gas outlet. The inner tube sealing card is arranged in the mounting hole, the length of the inner tube is the effective measuring optical path of the laser analyzer, an inner through hole connected to the sample gas inlet is arranged on the inner tube, a heating plate is arranged on one end of the two outer tubes away from the gas distributor, a transmitting unit of the laser analyzer and a receiving unit of the laser analyzer are respectively arranged on one end of the two outer tubes provided with the heating plate, a nitrogen purge hole is arranged on the transmitting unit of the laser analyzer and the receiving unit of the laser analyzer, and the nitrogen purge hole is connected to a nitrogen gas source through a nitrogen pipe.

2. The constant temperature extraction detection system for high temperature and high dust gas according to claim 1, characterized in that: A sealing cover is arranged in the first heating box, a primary filter is arranged in the sealing cover, a sample gas pipe in the differential pressure cyclone dust sampler passes through the first heating box and the sealing cover in sequence and is connected to the primary filter, a first recoil pipe is connected to the sealing cover, a second recoil pipe is connected to the first air supply pipe located in the second heating box, and both the first recoil pipe and the second recoil pipe are connected to a nitrogen gas source after passing through the second heating box.

3. The constant temperature extraction detection system for high temperature and high dust gas according to claim 2, characterized in that: A heat preservation sheath is arranged on the sample gas pipe, the lower end of the heat preservation sheath extends into the negative pressure flow guide pipe and is sealedly connected with the negative pressure flow guide pipe, and the upper end of the heat preservation sheath passes through the first heating box and is sealedly connected with the sealing cover.

4. The constant temperature extraction detection system for high temperature and high dust gas according to claim 3 is characterized in that: Two differential pressure cyclone dust collection samplers are arranged on the process pipeline, and the first air supply pipes on the two differential pressure cyclone dust collection samplers are connected to the same second air supply pipe.

5. The constant temperature extraction detection system for high temperature and high dust gas according to claim 1, characterized in that: A second ball valve is arranged on the second gas supply pipe, a detection pipe is connected to the second gas supply pipe between the second ball valve and the composite laser measuring pipe, a three-way valve is arranged on the detection pipe, one end of the three-way valve is connected to the zero gas source through the first branch pipe, and the other end of the three-way valve is connected to the standard gas source through the second branch pipe.

6. The constant temperature extraction detection system for high temperature and high dust gas according to claim 1, characterized in that: The two outer tubes are connected to the emitting unit and the receiving unit of the laser analyzer respectively through the reducing short section, and the reducing short section is sealed and fixed on the side wall of the third heating box. The emitting unit and the receiving unit of the laser analyzer are both located outside the third heating box.

7. A detection method, characterized in that: The constant temperature extraction detection system for high temperature and high dust gas according to any one of claims 1 to 6 is used, and the steps are as follows: S1. Start the first heating box, the second heating box, the third heating box and the heating cable, then open the first ball valve and the sampling pump. When the high-temperature gas in the process pipeline encounters the groove of the positive pressure guide pipe, it will move upward along the air intake gap, and then enter the exhaust gap from the outer air intake hole on the negative pressure guide pipe. The groove of the negative pressure guide pipe generates negative pressure due to air flow separation. The high-temperature gas entering the exhaust gap will flow downward under the action of negative pressure. The high-temperature gas will rotate at high speed under the guidance of the spiral disk. Under the centrifugal effect, the high-temperature gas will be stratified, and the high pressure gas near the sample gas pipe will be separated. The high-temperature gas is relatively clean, and there are large particles of dust in the high-temperature gas far away from the sample gas pipe. When the stratified high-temperature gas meets the inner air inlet downward, the high-temperature gas close to the sample gas pipe will enter the sample gas pipe under the action of the suction pressure of the sampling pump, and move toward the first gas pipeline as the high-temperature sample gas, while the large particles of dust will continue to move downward under the action of negative pressure with the high-temperature gas far away from the sample gas pipe until it falls back into the process pipeline. The high-temperature sample gas in the sample gas pipe enters the first gas pipeline after coarse filtration by the primary filter, and then enters the fine filter for fine filtration; S2. The nitrogen purge holes on the transmitting unit and the receiving unit of the laser analyzer are sprayed at the same time. The high-temperature sample gas that has been finely filtered first enters the inner tube through the gas distributor. The high-temperature sample gas gathers in the inner tube and gradually squeezes the nitrogen into the outer tube. When the inner tube is full of the high-temperature sample gas, the excess high-temperature sample gas diffuses into the outer tube and mixes with the nitrogen at both ends of the inner tube. The nitrogen is sealed at both ends of the inner tube. The transmitting unit and the receiving unit of the laser analyzer measure and analyze the high-temperature sample gas in the inner tube, thereby obtaining the concentration of each component in the high-temperature sample gas. S3. Nitrogen and high-temperature sample gas are mixed and flow back into the outer tube together and flow into the third gas pipeline through the reflux hole in the gas distributor. The third gas pipeline transports the mixed gas of nitrogen and high-temperature sample gas to the pressure-stabilizing discharge device for water washing and then discharges it.

8. The detection method according to claim 7, characterized in that: In S1, the heating temperature of the first heating box and the heating cable is 110-115°C, and the heating temperature of the second heating box and the third heating box is 120-125°C.

9. The detection method according to claim 7, characterized in that: In S1, the suction pressure of the sampling pump is greater than the gas pressure in the process pipeline. In S2, the suction pressure of the sampling pump is greater than the pressure of the nitrogen blown out from the nitrogen purge holes in the transmitting unit and the receiving unit of the laser analyzer.

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