A method for mixed hydrogen time division multiplexing measurement control of a natural gas pipeline

Abstract

This invention discloses a time-division multiplexing measurement and control method for mixing hydrogen in natural gas pipelines, including pipeline layout; testing and installation; signal modulation; natural gas and hydrogen transportation; concentration detection; and modeling and control. This invention provides a penetrable laser detection environment through a transparent glass pipe and utilizes longitudinally arranged TDLAS sensors to collect detection data, avoiding the impact of a single detection location on the accuracy of concentration data. During hydrogen separation, the TDLAS sensors monitor the gas concentration data in the transparent glass pipe in real time and establish a longitudinal distribution curve of natural gas concentration, providing a visualized concentration data model for the monitoring platform, improving the convenience of measurement and control. Simultaneously, the positions of the high and low level splitters are adjusted based on the gas concentration data to separate natural gas and hydrogen, thereby improving the practicality of the control method. This method can transport two different gases individually or simultaneously, reducing the transportation cost of hydrogen.

Description

Technical Field

[0001] This invention relates to the field of hydrogen-natural gas separation and control technology, specifically to a time-division multiplexing measurement and control method for hydrogen mixing in natural gas pipelines. Background Technology

[0002] Hydrogen-mixed natural gas is a gas mixture of hydrogen and natural gas. The mixed gas can be transported through existing natural gas pipelines and then separated for independent use, thus reducing the transportation cost of hydrogen. In the time-division multiplexing process of hydrogen-mixed natural gas, separation and control are required to separate the natural gas and hydrogen. However, existing measurement and control methods can only detect a single location in the pipeline, affecting the accuracy of concentration data detection. Furthermore, the height of the splitter plate cannot be adjusted during the separation process, affecting the practicality of the control method. At the same time, it is impossible to provide a visualized concentration data model for the monitoring platform after hydrogen separation, thus affecting the convenience of measurement and control. Therefore, it is necessary to design a measurement and control method for time-division multiplexing of hydrogen-mixed natural gas pipelines. Summary of the Invention

[0003] The purpose of this invention is to provide a time-division multiplexing measurement and control method for mixed hydrogen in natural gas pipelines, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a time-division multiplexing measurement and control method for mixing hydrogen in a natural gas pipeline, comprising the following steps: Step 1, pipeline layout; Step 2, testing and installation; Step 3, signal modulation; Step 4, natural gas and hydrogen transportation; Step 5, concentration detection; Step 6, modeling and control.

[0005] In step one above, a transparent glass pipe is arranged at the receiving end of the natural gas pipeline, and high and low diversion plates are arranged at the outlet of the transparent glass pipe. A hydrogen storage alloy throwing mechanism is set at the top of the transparent glass pipe, and a blower connected to the bottom of the transparent glass pipe is set at the bottom.

[0006] In step two above, a mounting bracket is arranged longitudinally along the direction of the transparent glass pipe, and a TDLAS sensor is fixedly installed on the mounting bracket. The laser emission port of the TDLAS sensor is perpendicular to the outer wall of the transparent glass pipe.

[0007] In step three above, before being put into use, a basic beam is emitted using a TDLAS sensor, and harmonics are extracted based on the results. Then, the signal emitted by the TDLAS sensor is modulated based on the information extracted from the harmonics.

[0008] In step four above, hydrogen and natural gas are mixed at the natural gas transmission source to obtain mixed hydrogen natural gas, which is then transported through a natural gas pipeline.

[0009] In step five above, after the mixed hydrogen natural gas enters the transparent glass pipe, the concentration is detected and analyzed by a TDLAS sensor arranged longitudinally on one side of the transparent glass pipe.

[0010] In step six above, the amount of hydrogen storage alloy to be thrown is determined based on the concentration detection and analysis results. Then, the hydrogen storage alloy is thrown through the hydrogen storage alloy throwing mechanism set at the top of the transparent glass pipe. At the same time, the blower set at the bottom of the transparent glass pipe provides air power to suspend the hydrogen storage alloy in the transparent glass pipe for separation. During the separation process, the TDLAS sensor detects the gas concentration data in the transparent glass pipe in real time and establishes a longitudinal distribution curve of natural gas concentration. After that, the transparent glass pipe is sent to the monitoring platform. At the same time, the position of the high and low level splitter plate is adjusted according to the gas concentration data to separate and transmit natural gas and hydrogen to the transportation terminal.

[0011] Preferably, in step one, the diameter of the natural gas pipeline receiving end is 2600mm, the material of the natural gas pipeline is L245, the transparent glass pipeline is connected to the receiving end of the natural gas pipeline through a flange, the transparent glass pipeline is arranged longitudinally, and the height of the transparent glass pipeline is 8000-10000mm.

[0012] Preferably, in step two, the spacing between the mounting brackets is 50-80mm, and the distance between the TDLAS sensor and the outer wall of the transparent glass pipe after installation is 10-15mm.

[0013] Preferably, in step three, the harmonic extraction process is as follows: First, the harmonic signal on the high-frequency component is transferred to the DC component through a multiplier phase detector and a low-pass filter. Then, Fourier cosine series expansion is performed on the exponential term in the signal. After that, the quadrature mixing signal is analyzed using a dual-phase lock-in amplifier. Then, the sinusoidal signal of the same frequency is adjusted, and the high-frequency information is filtered out from the original signal through a low-pass filter. After filtering, the feedback amplitude information of the signal is obtained.

[0014] Preferably, in step four, the amount of hydrogen added during the hydrogen mixing process is 5% to 8% of the natural gas volume, and the hydrogen pressure in the mixed hydrogen natural gas is 1.25 to 1.85 MPa.

[0015] Preferably, in step five, the concentration detection and analysis process is as follows: First, a light beam is emitted by the TDLAS sensor. After the light beam enters the transparent glass tube, the light intensity is attenuated under the action of the mixed hydrogen and natural gas. Then, the attenuated light wave is received by the receiving part, and the absorbance of the spectrum is calculated according to the Lambert-Beer law. Subsequently, the natural gas content and hydrogen content in the transparent glass tube are calculated respectively based on the absorbance value, thus completing the concentration detection and analysis process.

[0016] Preferably, in step six, the temperature in the transparent glass tube during the separation process is 300–350°C, and the separation rate is 200–280 m / s. 3 / h.

[0017] Compared with existing technologies, the beneficial effects of this invention are as follows: This time-division multiplexing measurement and control method for mixing hydrogen in natural gas pipelines provides a penetrable laser detection environment through a transparent glass tube, while using longitudinally arranged TDLAS sensors to collect detection data, avoiding the impact of a single detection location on the accuracy of concentration data detection; during separation processing, the amount of hydrogen storage alloy thrown is adjusted according to the detection data; during hydrogen separation, the TDLAS sensors detect the gas concentration data in the transparent glass tube in real time and establish a longitudinal distribution curve of natural gas concentration, and then send the transparent glass tube to the monitoring platform, providing the monitoring platform with a visualized concentration data model, thereby improving the convenience of measurement and control; at the same time, the position of the high and low level splitter plates is adjusted according to the gas concentration data to separate and transmit natural gas and hydrogen to the transportation terminal, improving the practicality of the control method. Attached Figure Description

[0018] Figure 1 This is a flowchart of the method of the present invention;

[0019] Figure 2 This is a schematic diagram illustrating the operation of another embodiment of the method of the present invention.

[0020] Component descriptions in the diagram: 1-Natural gas pipeline; 2-Transparent glass pipeline; 3-Optical gas detector; 4-Intelligent analysis gas separation control switch; 5-Diverter plate; 6-Hydrogen storage alloy throwing mechanism; 7-Blower; 8-Blowing pipeline; 9-Gas distributor; 91-Hydrogen outlet; 92-Natural gas outlet; 11-Hydrogen; 12-Natural gas. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figure 1 The present invention provides an embodiment of a time-division multiplexing measurement and control method for mixing hydrogen in a natural gas pipeline, comprising the following steps: Step 1, pipeline layout; Step 2, testing and installation; Step 3, signal modulation; Step 4, natural gas and hydrogen transportation; Step 5, concentration detection; Step 6, modeling and control.

[0023] In step one above, a transparent glass pipe is arranged at the receiving end of the natural gas pipeline, and high and low diversion plates are arranged at the outlet of the transparent glass pipe. The diameter of the receiving end of the natural gas pipeline is 2600mm, and the material of the natural gas pipeline is L245. The transparent glass pipe is connected to the receiving end of the natural gas pipeline through a flange. The transparent glass pipe is arranged longitudinally, and the height of the transparent glass pipe is 8000-10000mm. A hydrogen storage alloy throwing mechanism is set at the top of the transparent glass pipe, and a blowing pipe connected to a blower is set at the bottom of the transparent glass pipe.

[0024] In step two above, mounting brackets are arranged longitudinally along the direction of the transparent glass pipe, with a spacing of 50-80mm between the mounting brackets. TDLAS sensors are fixedly installed on the mounting brackets. After installation, the distance between the TDLAS sensors and the outer wall of the transparent glass pipe is 10-15mm. The laser emission port of the TDLAS sensors is perpendicular to the outer wall of the transparent glass pipe.

[0025] In step three above, before being put into use, a basic beam is emitted using a TDLAS sensor, and harmonics are extracted based on the results. The harmonic extraction process is as follows: First, the harmonic signals on the high-frequency components are transferred to the DC components through a multiplier phase detector and a low-pass filter. Then, a Fourier cosine series expansion is performed on the exponential term in the signal. After that, a dual-phase lock-in amplifier is used to analyze the quadrature mixing signal. Then, a sine wave signal of the same frequency is adjusted, and the high-frequency information is filtered out from the original signal through a low-pass filter. After filtering, the feedback amplitude information of the signal is obtained. Then, the signal emitted by the TDLAS sensor is modulated based on the harmonic extraction information.

[0026] In step four above, hydrogen and natural gas are mixed at the natural gas transmission source to obtain hydrogen-mixed natural gas. The amount of hydrogen added during the hydrogen-mixing process is 5% to 8% of the volume of natural gas, and the hydrogen pressure in the mixed hydrogen-mixed natural gas is 1.25 to 1.85 MPa. Then, the mixed hydrogen-mixed natural gas is transported using a natural gas pipeline.

[0027] In step five above, after the mixed hydrogen natural gas enters the transparent glass pipe, the concentration is detected and analyzed by a TDLAS sensor arranged longitudinally on one side of the transparent glass pipe. The concentration detection and analysis process is as follows: First, the TDLAS sensor emits a light beam. After the light beam enters the transparent glass pipe, the light intensity is attenuated under the action of the mixed hydrogen natural gas. Then, the attenuated light wave is received by the receiving part, and the absorbance of the spectrum is calculated according to the Lambert-Beer law. Subsequently, the natural gas content and hydrogen content in the transparent glass pipe are calculated separately based on the absorbance value, thus completing the concentration detection and analysis process.

[0028] In step six above, the amount of hydrogen storage alloy to be thrown is determined based on the concentration detection and analysis results. Then, the hydrogen storage alloy is thrown through a throwing mechanism located at the top of the transparent glass pipe. Simultaneously, a blower located at the bottom of the transparent glass pipe provides airflow to suspend the hydrogen storage alloy within the pipe for separation. During the separation process, the temperature inside the transparent glass pipe is 300–350°C, and the separation rate is 200–280 m / s. 3 During the separation process, the TDLAS sensor detects the gas concentration data in the transparent glass tube in real time and establishes a longitudinal distribution curve of natural gas concentration. Then, the transparent glass tube is sent to the monitoring platform. At the same time, the position of the high and low level splitter plate is adjusted according to the gas concentration data to separate natural gas and hydrogen and transmit them to the transportation terminal.

[0029] Based on the above, the advantages of this invention are as follows: This invention provides a penetrable laser detection environment through a transparent glass tube, while using longitudinally arranged TDLAS sensors to collect detection data, avoiding the impact of a single detection location on the accuracy of concentration data. During separation processing, the amount of hydrogen storage alloy thrown is adjusted according to the detection data. During hydrogen separation, the TDLAS sensors detect the gas concentration data in the transparent glass tube in real time and establish a longitudinal distribution curve of natural gas concentration. The transparent glass tube is then sent to a monitoring platform, providing the platform with a visualized concentration data model, thereby improving the convenience of measurement and control. Simultaneously, the positions of the high and low level splitters are adjusted according to the gas concentration data to separate and transmit natural gas and hydrogen to the transportation terminal, improving the practicality of the control method.

[0030] Please refer to Figure 2 As another embodiment of the present invention, a time-division multiplexing measurement and control method for mixing hydrogen in a natural gas pipeline includes the following steps: Step 1, pipeline layout; Step 2, testing and installation; Step 3, signal modulation; Step 4, natural gas and hydrogen transportation; Step 5, concentration detection; Step 6, modeling and control.

[0031] Based on the above, in this embodiment, a transparent glass pipe 2 is arranged at the receiving end of the natural gas pipeline 1, and optical gas detectors 3 and intelligent gas separation control switches 4 are arranged on both sides of the outlet of the transparent glass pipe 2. A high and low diversion plate 5 is arranged on the right side of the outlet of the transparent intermediate glass pipe 2. A hydrogen storage alloy throwing mechanism 6 is arranged on the upper middle side of the diversion plate 5, and a blower 7 and a blowing pipe 8 connected to the blower 7 are arranged on the lower middle side of the diversion plate 5. A gas splitter 9 is arranged at the end of the diversion plate 5. A hydrogen outlet 91 and a natural gas outlet 92 are respectively arranged on the upper and lower sides of the gas splitter 9. When hydrogen 11 and natural gas 12 enter the natural gas pipeline 1 at the same time, the optical gas detector 3 starts to detect. When the mixed gas stops entering, the intelligent analysis gas separation control switch 4 separates the entering mixed gas. The separated gas enters the transparent glass pipe 2. Among them, hydrogen 11 enters the upper side of the diverter plate 5, and natural gas enters the lower side of the diverter plate 5. Then, it enters the gas distributor 9 for analysis and diversion. The diverted hydrogen 11 flows out from the hydrogen outlet 91 and is collected. The diverted natural gas 12 flows out from the natural gas outlet 92 and is collected. The hydrogen 11 remaining on the upper side of the diverter plate 5 can be recovered by throwing hydrogen storage alloy into the hydrogen storage alloy throwing mechanism 6. The remaining natural gas 12 can be blown into the gas distributor 9 by blowing strong air into the blowing pipe 8 by the blower 7, and then collected through the natural gas outlet 92.

[0032] Based on the above, in this embodiment, hydrogen and natural gas can be transported through pipelines at different times, or they can be transported together. When the two gases cannot be avoided due to residue, the gas being transported through the pipeline can be analyzed by a TDLS sensor at the end of the transport, and different gas pipelines can be controlled by valves according to the type of gas. The pipeline can reuse two different gases, or the mixed gas can be transported through the original natural gas pipeline. After the transport is completed, it can be separated and used independently to reduce the transportation cost of hydrogen.

[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A time-division multiplexing measurement and control method for mixed hydrogen in a natural gas pipeline, comprising the following steps: Step 1, Pipeline layout; Step 2, Testing and installation; Step 3, Signal modulation; Step 4, Natural gas and hydrogen delivery; Step 5, Concentration detection; Step 6, Modeling and control; Its features are: In step one above, a transparent glass pipe is arranged at the receiving end of the natural gas pipeline, and a high and low diversion plate is arranged at the outlet of the transparent glass pipe. A hydrogen storage alloy throwing mechanism is set at the top of the transparent glass pipe, and a blowing pipe connected to a blower is set at the bottom of the transparent glass pipe. In step two above, a mounting bracket is arranged longitudinally along the direction of the transparent glass pipe, and a TDLAS sensor is fixedly installed on the mounting bracket. The laser emission port of the TDLAS sensor is perpendicular to the outer wall of the transparent glass pipe. In step three above, before being put into use, a basic beam is emitted using a TDLAS sensor, and harmonics are extracted based on the results. Then, the signal emitted by the TDLAS sensor is modulated based on the information extracted from the harmonics. In step four above, hydrogen and natural gas are mixed at the natural gas transmission source to obtain mixed hydrogen natural gas, which is then transported through a natural gas pipeline. In step five above, after the mixed hydrogen natural gas enters the transparent glass pipe, the concentration is detected and analyzed by a TDLAS sensor arranged longitudinally on one side of the transparent glass pipe. In step six above, the amount of hydrogen storage alloy to be thrown is determined based on the concentration detection and analysis results. Then, the hydrogen storage alloy is thrown through the hydrogen storage alloy throwing mechanism set at the top of the transparent glass pipe. At the same time, the blower set at the bottom of the transparent glass pipe provides air power to suspend the hydrogen storage alloy in the transparent glass pipe for separation. During the separation process, the TDLAS sensor detects the gas concentration data in the transparent glass pipe in real time and establishes a longitudinal distribution curve of natural gas concentration. Then, the gas concentration data of the transparent glass pipe is sent to the monitoring platform. At the same time, the position of the high and low level splitter plate is adjusted according to the gas concentration data to separate and transmit natural gas and hydrogen to the transportation terminal.

2. The time-division multiplexing measurement and control method for mixed hydrogen in a natural gas pipeline according to claim 1, characterized in that: In step one, the diameter of the natural gas pipeline receiving end is 2600mm, and the material of the natural gas pipeline is L245. The transparent glass pipeline is connected to the receiving end of the natural gas pipeline through a flange. The transparent glass pipeline is arranged longitudinally, and the height of the transparent glass pipeline is 8000-10000mm.

3. The time-division multiplexing measurement and control method for mixed hydrogen in a natural gas pipeline according to claim 1, characterized in that: In step two, the spacing between the mounting brackets is 50-80mm, and the distance between the TDLAS sensor and the outer wall of the transparent glass pipe after installation is 10-15mm.

4. The time-division multiplexing measurement and control method for mixed hydrogen in a natural gas pipeline according to claim 1, characterized in that: In step three, the harmonic extraction process is as follows: First, the harmonic signal on the high-frequency component is transferred to the DC component through a multiplication phase detector and a low-pass filter. Then, a Fourier cosine series expansion is performed on the exponential term in the signal. After that, a dual-phase lock-in amplifier is used to analyze the quadrature mixing signal. Then, a sine wave signal of the same frequency is adjusted, and the high-frequency information is filtered out from the original signal through a low-pass filter. After filtering, the feedback amplitude information of the signal is obtained.

5. The time-division multiplexing measurement and control method for mixed hydrogen in a natural gas pipeline according to claim 1, characterized in that: In step four, the amount of hydrogen added during the hydrogen mixing process is 5% to 8% of the natural gas volume, and the hydrogen pressure in the mixed hydrogen natural gas is 1.25 to 1.85 MPa.

6. The time-division multiplexing measurement and control method for mixed hydrogen in a natural gas pipeline according to claim 1, characterized in that: In step five, the concentration detection and analysis process is as follows: First, the TDLAS sensor emits a light beam. After the light beam enters the transparent glass pipe, the light intensity is attenuated under the action of the mixed hydrogen and natural gas. Then, the attenuated light wave is received by the receiving part, and the absorbance of the spectrum is calculated according to the Lambert-Beer law. Subsequently, the natural gas content and hydrogen content in the transparent glass pipe are calculated respectively based on the absorbance value, thus completing the concentration detection and analysis process.

7. The time-division multiplexing measurement and control method for mixed hydrogen in a natural gas pipeline according to claim 1, characterized in that: In step six, the temperature inside the transparent glass pipe during the separation process is 300–350°C, and the separation rate is 200–280 m / s. 3 / h.

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