In-situ laser gas analyzer

Abstract

The invention discloses an in-situ laser gas analyzer, and relates to the technical field of gas detection, the in-situ laser gas analyzer comprises two sets of detection systems, each detection system comprises a filter assembly, a gas pump, a flowmeter and a sensor which are connected in sequence, and the gas outlet end of each filter assembly is connected with a blowback pipe; a flow dividing pipe and a calibration pipe are sequentially connected to the portion, between the air pump and the flow meter, of the air conveying pipe in the air conveying direction, the calibration pipe is connected with the air conveying pipe through a three-way valve, and the three-way valve is used for controlling the flow meter to be selectively communicated with the air pump or the calibration pipe. According to the in-situ laser gas analyzer, the gas pump is arranged between the filtering assembly and the sensor to overcome the resistance of the filtering assembly, and part of gas is guided and discharged through the flow dividing pipe, so that measurement errors caused by too large flow are avoided; in addition, the flow meter is used for detecting the gas flow entering the sensor so as to judge whether the gas flow is in a preset range or not, and the gas detection accuracy is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of gas detection, in particular to an in-situ laser gas analyzer. Background Art

[0002] Coal mine gas is mainly methane. Gas oxidation heating technology can convert less than 8% of gas into thermal energy, replacing coal-fired boilers for heating, reducing pollution and improving efficiency. The principle of this technology is high-temperature methane oxidation. By collecting gas, mixing it to a concentration of 1.2%, and then sending it to the oxidation device, it undergoes flameless oxidation at a high temperature of more than 900°C, releasing heat for heating or power generation.

[0003] In the NB_T 10855-2021CN coal mine gas thermal regenerative oxidation device power generation technical specification, there are also corresponding requirements for gas online monitoring equipment: the response time for measuring the methane concentration of the mixed gas entering the oxidation device is no more than 1.5s, and the measurement response time for the methane concentration of the extraction gas, the methane concentration of the exhaust gas (lack of air), and the methane concentration of the flue gas is no more than 2.5s. The absolute error of the gas methane concentration sensor is less than ±0.05%.

[0004] Therefore, accurate and rapid measurement of methane concentration plays an important role in low-concentration methane utilization projects. Summary of the invention

[0005] 1. Technical issues to be resolved The purpose of the present invention is to provide an in-situ laser gas analyzer with accurate gas detection, so as to achieve the purpose of rapid and accurate measurement of methane concentration.

[0006] (II) Technical solution To achieve the above objectives, the present invention is implemented through the following technical solutions: an in-situ laser gas analyzer, comprising two detection systems, the detection system comprising a filter assembly, an air pump, a flow meter and a sensor connected in sequence, the gas outlet end of the filter assembly being connected to a backflush pipe; The gas supply pipe between the air pump and the flow meter is connected with a shunt pipe and a calibration pipe in sequence along the gas supply direction. The calibration pipe is connected to the gas supply pipe through a three-way valve. The three-way valve is used to control the flow meter to selectively connect with the air pump or the calibration pipe.

[0007] Preferably, the filter assembly comprises a plurality of filters, and the plurality of filters are connected in parallel or in series.

[0008] Preferably, the backblowing pipe is connected to the gas supply pipe through a third three-position two-way valve, the air inlet of the third three-position two-way valve is connected to the filter assembly, and the two air outlets of the third three-position two-way valve are respectively connected to the air pump and the backblowing pipe.

[0009] Preferably, it also includes a waste pipe, wherein the backflush pipe, the waste pipe and the filter assembly are arranged in parallel on the gas pipeline, and the backflush pipe and the waste pipe are both connected to the gas pipeline through a reversing valve, and the reversing valve is used to control the connection state of the backflush pipe and the waste pipe with the gas pipeline; During the test, the gas to be tested flows through the filter assembly; During backflush, the measured gas flows through the backflush pipe, filter assembly and exhaust pipe in sequence.

[0010] Preferably, the reversing valve includes a first three-position two-way valve and a second three-position two-way valve, wherein the two air outlet ends of the first three-position two-way valve are respectively connected to the backblowing pipe and the air inlet end of the filter assembly, and the two air inlet ends of the second three-position two-way valve are respectively connected to the exhaust pipe and the air outlet end of the filter assembly.

[0011] Preferably, it also includes a box body, and the filter assembly, air pump, three-way valve, flow meter and sensor are all fixedly connected to the inside of the box body, and the box body is provided with an air inlet interface, a calibration gas interface, an exhaust interface and a purge gas interface.

[0012] Preferably, the air inlet end of the air supply pipe is connected to the air inlet interface, the air outlet ends of the air supply pipe and the diversion pipe are both connected to the exhaust interface, and the air inlet end of the calibration tube is connected to the calibration gas interface.

[0013] Preferably, the air intake interface is connected to an air intake probe gun, and the air intake probe gun is fixedly connected to the outside of the box.

[0014] Preferably, one of the air intake probe guns extends into the inner edge of the pipeline to be tested, and the other air intake probe gun extends into the middle of the pipeline to be tested.

[0015] (III) Beneficial effects Compared with the prior art, the present invention provides an in-situ laser gas analyzer, which has the following beneficial effects: 1. The in-situ laser gas analyzer performs dual-sensor detection by setting up two detection systems, taking distributed samples at the center and edge of the gas delivery pipe to be tested, and cross-certifying the data of the two to ensure the accuracy of the detection.

[0016] 2. The in-situ laser gas analyzer is equipped with an air intake probe gun, which is inserted into the gas delivery pipeline to be tested during installation. It is easy to install and can seamlessly replace the original online monitoring system. At the same time, it can realize in-situ detection and improve response speed.

[0017] 3. The in-situ laser gas analyzer is provided with a temperature sensor, a cooling fan and an electric heating module to control the detection system within a suitable temperature range, improve environmental adaptability and avoid detection errors.

[0018] 4. The in-situ laser gas analyzer can realize automatic purging, and the purging frequency can be set according to the impurity content of the gas to ensure its stable operation.

[0019] 5. The in-situ laser gas analyzer sets an air pump between the filter assembly and the sensor to overcome the resistance of the filter assembly, and guides part of the gas to be discharged through a shunt pipe to avoid measurement errors caused by excessive flow. In addition, the gas flow entering the sensor is detected by a flow meter to determine whether the gas flow is within a preset range to ensure the accuracy of gas detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic front view of an embodiment of the present invention; Figure 2 For the present invention Figure 1 Schematic diagram of the process; Figure 3 A schematic front view of another embodiment of the present invention; Figure 4 For the present invention Figure 3 Schematic diagram of the process.

[0021] Figure 5 This is a schematic diagram of the use status of the present invention.

[0022] In the figure: 1. Filter assembly; 2. Air inlet interface; 3. First three-position two-way valve; 4. Air pump; 5. Second three-position two-way valve; 6. Calibration gas interface; 7. Flow meter; 8. Sensor; 9. Three-way valve; 10. Exhaust interface; 11. Purge gas interface; 12. Third three-position two-way valve; 13. Box; 14. Air inlet probe; 15. Cooling fan. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0024] See also Figure 1-5 As shown, an in-situ laser gas analyzer includes two detection systems, the detection system includes a filter assembly 1, an air pump 4, a flow meter 7 and a sensor 8 connected in sequence, the air outlet of the filter assembly 1 is connected with a backflush pipe; the air delivery pipe between the air pump 4 and the flow meter 7 is connected with a shunt pipe and a calibration pipe in sequence along the air delivery direction, the calibration pipe is connected to the air delivery pipe through a three-way valve 9, and the three-way valve 9 is used to control the flow meter 7 to selectively communicate with the air pump 4 or the calibration pipe. Specifically, the sensor 8 is a laser gas sensor.

[0025] When in use, the air pump 4 is started to generate negative pressure, and the gas to be tested enters the filter assembly 1 through the gas delivery pipe, and the impurities in the gas are filtered by the filter assembly 1. After filtering, part of the gas to be tested enters the sensor 8, and is detected by the sensor 8, and the other part is guided and discharged by the shunt pipe to avoid measurement errors caused by excessive flow. The gas flow entering the sensor 8 can be detected by the flow meter 7 to determine whether the gas flow is within a preset range to ensure the accuracy of gas detection.

[0026] When the sensor 8 needs to be calibrated, the calibration tube is connected to the sensor 8 through the three-way valve 9, and the calibration gas is introduced into the sensor 8 through the calibration tube to calibrate the sensor 8; when the filter component 1 needs to be cleaned, the sensor 8 is disconnected from the filter component 1 through the three-way valve 9, and the purge gas is supplied to the filter component 1 through the backflush tube to backflush and clean the filter component 1.

[0027] By setting up two detection systems, the data from both systems are cross-certified during detection to ensure the accuracy of the detection.

[0028] Specifically, the filter assembly 1 includes a plurality of filters, and the plurality of filters are connected in parallel or in series. By connecting a plurality of filters in parallel, the gas filtering efficiency can be improved; by connecting a plurality of filters in series, the gas filtering effect can be improved.

[0029] In some embodiments, see Figure 3-4 As shown, an external air source is used to backflush and clean the filter assembly 1, the backflush pipe is connected to the air supply pipe through the third three-position two-way valve 12, the air inlet of the third three-position two-way valve 12 is connected to the filter assembly 1, and the two air outlets of the third three-position two-way valve 12 are respectively connected to the air pump 4 and the backflush pipe.

[0030] When backflush cleaning is performed, the backflush pipe is connected to the filter assembly 1 through the third three-position two-way valve 12, nitrogen is pumped into the backflush pipe, the filter assembly 1 is backflush cleaned by nitrogen, and the exhaust gas is discharged from the air inlet end of the air supply pipe.

[0031] In some embodiments, see Figure 1-2 As shown, the on-site gas is used for back-blowing cleaning, and the back-blowing pipe, the back-blowing pipe and the filter assembly 1 are arranged in parallel on the gas pipeline. The back-blowing pipe and the back-blowing pipe are connected to the gas pipeline through a reversing valve. The reversing valve is used to control the connection state of the back-blowing pipe and the back-blowing pipe with the gas pipeline; During the test, the gas to be tested flows through the filter assembly 1 and then flows to the air pump 4, without flowing through the backflush pipe and the impurity exhaust pipe; During backblowing, the air pump 4 is started, the measured gas flows through the backblowing pipe and then backblown and cleans the filter assembly 1. The airflow carries impurities into the exhaust pipe and then flows into the diversion pipe for discharge. During this process, the sensor 8 is disconnected from the filter assembly 1 through the three-way valve 9 to prevent impurities from entering the flow meter 7 and the sensor 8.

[0032] Specifically, the reversing valve includes a first three-position two-way valve 3 and a second three-position two-way valve 5. The two air outlet ends of the first three-position two-way valve 3 are respectively connected to the backblowing pipe and the air inlet end of the filter assembly 1, and the two air inlet ends of the second three-position two-way valve 5 are respectively connected to the exhaust pipe and the air outlet end of the filter assembly 1.

[0033] This method is used to clean the filter assembly 1 without the need for an external air source, making the cleaning more convenient.

[0034] The first three-position two-way valve 3, the second three-position two-way valve 5, the third three-position two-way valve 12 and the three-way valve 9 are all solenoid valves, and are all connected to a controller so that the purge frequency can be set according to the impurity content of the gas through the controller.

[0035] In some embodiments, it also includes a box 13, the filter assembly 1, the air pump 4, the three-way valve 9, the flow meter 7 and the sensor 8 are all fixedly connected inside the box 13, and the box 13 is provided with an air inlet interface 2, a calibration gas interface 6, an exhaust interface 10 and a purge gas interface 11. Specifically, the air inlet end of the gas pipe is connected to the air inlet interface 2, the air outlet ends of the gas pipe and the shunt pipe are connected to the exhaust interface 10, and the air inlet end of the calibration pipe is connected to the calibration gas interface 6. Preferably, a temperature sensor and an electric heating module are fixedly connected inside the box 13, and a heat dissipation fan 15 is fixedly connected to the box 13. The temperature inside the box 13 is detected by the temperature sensor, and the electric heating module or the heat dissipation fan 15 is started according to the detected temperature to control the temperature inside the box 13 within an appropriate range to avoid affecting the detection accuracy.

[0036] In some embodiments, the air inlet interface 2 is connected to an air inlet probe gun 14, which is fixedly connected to the outside of the box 13; one of the air inlet probe guns 14 extends into the inner edge of the pipeline to be tested, and the other air inlet probe gun 14 extends into the middle of the pipeline to be tested.

[0037] By setting up two detection systems to perform dual sensor 8 detection, distributed sampling is performed on the center and edge of the gas delivery pipe to be tested, and the data of the two are cross-certified and averaged to ensure the accuracy of the detection.

[0038] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An in-situ laser gas analyzer, characterized in that: It comprises two detection systems, wherein the detection system comprises a filter assembly (1), an air pump (4), a flow meter (7) and a sensor (8) which are connected in sequence, and the air outlet end of the filter assembly (1) is connected to a backflush pipe; A shunt pipe and a calibration pipe are sequentially connected to the gas delivery pipe between the gas pump (4) and the flow meter (7) along the gas delivery direction; the calibration pipe is connected to the gas delivery pipe via a three-way valve (9); the three-way valve (9) is used to control the flow meter (7) to selectively communicate with the gas pump (4) or the calibration pipe.

2. An in-situ laser gas analyzer according to claim 1, characterized in that: The filter assembly (1) comprises a plurality of filters, and the plurality of filters are connected in parallel or in series.

3. The in-situ laser gas analyzer according to claim 1, characterized in that: The back-blowing pipe is connected to the gas supply pipe via a third three-position two-way valve (12); the air inlet of the third three-position two-way valve (12) is connected to the filter assembly (1); and the two air outlets of the third three-position two-way valve (12) are respectively connected to the air pump (4) and the back-blowing pipe.

4. The in-situ laser gas analyzer according to claim 1, characterized in that: The device also includes a waste pipe, wherein the backflush pipe, the waste pipe and the filter assembly (1) are arranged in parallel on the gas pipeline, and the backflush pipe and the waste pipe are both connected to the gas pipeline via a reversing valve, and the reversing valve is used to control the connection state between the backflush pipe and the waste pipe and the gas pipeline; During the test, the gas to be tested flows through the filter assembly (1); During backflush, the gas to be measured flows through the backflush pipe, the filter assembly (1) and the exhaust pipe in sequence.

5. The in-situ laser gas analyzer according to claim 4, characterized in that: The reversing valve comprises a first three-position two-way valve (3) and a second three-position two-way valve (5), wherein two air outlet ends of the first three-position two-way valve (3) are respectively connected to the backflush pipe and the air inlet end of the filter assembly (1), and two air inlet ends of the second three-position two-way valve (5) are respectively connected to the impurity discharge pipe and the air outlet end of the filter assembly (1).

6. The in-situ laser gas analyzer according to claim 1, characterized in that: It also comprises a box (13), wherein the filter assembly (1), the air pump (4), the three-way valve (9), the flow meter (7) and the sensor (8) are all fixedly connected inside the box (13), and the box (13) is provided with an air inlet interface (2), a calibration gas interface (6), an exhaust interface (10) and a purge gas interface (11).

7. The in-situ laser gas analyzer according to claim 6, characterized in that: The air inlet end of the air supply pipe is connected to the air inlet interface (2), the air outlet ends of the air supply pipe and the shunt pipe are both connected to the exhaust interface (10), and the air inlet end of the calibration pipe is connected to the calibration gas interface (6).

8. The in-situ laser gas analyzer according to claim 6, characterized in that: The air intake interface (2) is connected to an air intake probe gun (14), and the air intake probe gun (14) is fixedly connected to the outside of the box body (13).

9. The in-situ laser gas analyzer according to claim 8, characterized in that: One of the air intake probe guns (14) extends into the inner edge of the pipeline to be tested, and the other air intake probe gun (14) extends into the middle of the pipeline to be tested.

Images