Hydrogen-doped natural gas pressure regulating system and method in limited space

Abstract

The application discloses a hydrogen-doped natural gas pressure regulating system and method in a limited space, and relates to the field of gas pressure control. The system comprises a main pipeline arranged between a gas source and an experimental area, at least one pressure coarse adjusting device and at least one pressure sensor device for detecting the gas pressure entering the experimental area through the main pipeline are arranged on the main pipeline in sequence along the gas flow direction of the main pipeline; at least one branch pipeline is connected to the main pipeline between the pressure coarse adjusting device and the pressure sensor device, and a pressure fine adjusting device is arranged on the branch pipeline; and a control system is arranged. When the pressure coarse adjusting device fails to adjust the gas pressure of the main pipeline to the target preset pressure range, the control system controls the pressure fine adjusting device to finely adjust the gas pressure in the main pipeline, so that the gas pressure in the main pipeline is maintained in the target preset pressure range. In this way, the space utilization and system safety are improved, and the automatic regulation and control of the hydrogen-doped natural gas pressure are realized.

Description

Technical Field

[0001] This invention relates to the field of gas pressure control, and more specifically to a hydrogen-blended natural gas pressure regulation system and method in a confined space. Background Technology

[0002] Currently, with the continuous advancement of the dual-carbon goals, research on hydrogen and hydrogen-blended natural gas is being conducted in greater depth and on a larger scale. Traditional natural gas and hydrogen-blended natural gas differ in physical properties, performance requirements for containment materials, leakage diffusion rates, and the consequences and impact range of leakage-induced combustion and explosion accidents. Related research explores their variation patterns through various methods such as calculation and simulation; however, experimental simulation and testing are the most intuitive and reliable research methods, helping to overcome the limitations of the models themselves and obtain more realistic and accurate data.

[0003] The end users of urban gas are mainly urban residents and industrial users, and urban gas is generally transported through low-pressure pipelines. During urban pipeline maintenance and emergency repairs, techniques such as live welding are commonly used. These operations involve a low-pressure or atmospheric-pressure gas environment with a relative pressure of 50 Pa to 1000 Pa. The blending of natural gas with hydrogen may introduce new risks and hazards to live welding operations, including changes in flame height, flame stability, flame temperature, and other combustion characteristics, as well as alterations in the material properties of the weld joint. These issues require further experimental research.

[0004] Because the relative pressure of 50Pa to 1000Pa is relatively low, the configuration pressure of hydrogen-blended natural gas is generally above 0.1MPa. When hydrogen-blended natural gas is reduced from a high pressure level to a low pressure level, the gas volume is negatively correlated with the pressure; the volume expansion rate is high when the pressure drops significantly, and the gas temperature also changes. The combined change in temperature and gas volume can lead to significant pressure fluctuations even after pressure regulation, resulting in unstable experimental pressure. Therefore, low-pressure or atmospheric-pressure experiments with hydrogen-blended natural gas require high pressure regulation and stabilization capabilities from the equipment. Consequently, regulating and maintaining pressure stability during the transportation of hydrogen-blended natural gas presents certain technical challenges. Existing technologies generally utilize long-distance buffer pipelines, large-volume buffer tanks, or a combination of both to achieve pressure stabilization after regulation. These systems occupy a large area and involve numerous welds. After natural gas is blended with hydrogen, hydrogen atoms may accumulate at welds and other locations, leading to hydrogen loss and other problems, introducing new hidden dangers to the experiment.

[0005] In existing experimental systems, buffer tanks or buffer pipelines are often introduced to ensure pressure stability. However, buffer tanks are positive pressure vessels and may experience problems such as media leakage. When natural gas is mixed with hydrogen, there is an even higher risk of leakage at the sealed connections and welds of the buffer pipelines. Both of these methods will increase the risk level of the system. At the same time, the introduction of buffer tanks or buffer pipelines will also increase space requirements and construction and maintenance costs. Summary of the Invention

[0006] The purpose of this invention is to provide a hydrogen-blended natural gas pressure regulating system and method in a limited space, which solves the problems of low space utilization, low safety and high cost in the existing hydrogen-blended natural gas pressure regulating system.

[0007] The above-mentioned objectives of the present invention can be achieved by the following technical solutions:

[0008] This invention provides a hydrogen-blended natural gas pressure regulating system in a confined space, comprising:

[0009] A main pipeline is used to be located between the gas source and the experimental area. Along the gas flow direction in the main pipeline, at least one pressure coarse adjustment device and at least one pressure sensing device are sequentially provided on the main pipeline. The pressure coarse adjustment device is used to adjust the gas pressure flowing into the main pipeline to a target preset pressure range, and the pressure sensing device is used to detect the pressure of the gas entering the experimental area through the main pipeline.

[0010] At least one branch pipeline, one end of which is connected to the main pipeline between the pressure coarse adjustment device and the pressure sensing device, and the branch pipeline is provided with a pressure fine adjustment device, which is used to adjust and maintain the gas pressure in the main pipeline within a target preset pressure range.

[0011] The control system is electrically connected to the pressure coarse adjustment device, the pressure sensing device, and the pressure fine adjustment device. When the pressure coarse adjustment device fails to adjust the gas pressure in the main pipeline to the target preset pressure range, the control system controls the pressure fine adjustment device to perform pressure fine adjustment on the gas in the main pipeline.

[0012] In one specific embodiment, when the pressure coarse adjustment device fails to adjust the gas pressure in the main pipeline to the first preset pressure range, the control system controls the pressure coarse adjustment device to adjust the gas pressure in the main pipeline; when the pressure coarse adjustment device adjusts the gas pressure in the main pipeline to the first preset pressure range, the control system controls the pressure fine adjustment device to fine adjust the gas pressure in the main pipeline.

[0013] In one specific embodiment, the first preset pressure range includes a first preset pressure interval and a second preset pressure interval. The minimum value of the first preset pressure interval is greater than the maximum value of the target preset pressure range, and the maximum value of the second preset pressure interval is less than the minimum value of the target preset pressure range. When the pressure coarse adjustment device adjusts the gas pressure in the main pipeline to the first preset pressure interval of the first preset pressure range, the control system controls the pressure fine adjustment device to increase its opening to finely adjust the gas pressure in the main pipeline, so that the gas pressure in the main pipeline is within the target preset pressure range. When the pressure coarse adjustment device adjusts the gas pressure in the main pipeline to the second preset pressure interval of the first preset pressure range, the control system controls the pressure fine adjustment device to decrease its opening to finely adjust the gas pressure in the main pipeline, so that the gas pressure in the main pipeline is within the target preset pressure range.

[0014] In one specific embodiment, the main pipeline is provided with a multi-stage pressure coarse adjustment device and a plurality of pressure sensing devices, which are arranged alternately along the gas flow direction in the main pipeline.

[0015] In one specific embodiment, the hydrogen-blended natural gas pressure regulating system includes multiple branch pipelines, one end of each branch pipeline being connected to a main pipeline between the adjacent pressure coarse adjustment device and the pressure sensing device.

[0016] In one specific embodiment, the hydrogen-blended natural gas pressure regulating system further includes a venting pipeline, which is connected to the other end of the branch pipeline, and a venting system is connected to the venting pipeline.

[0017] In one specific embodiment, each of the branch pipelines is provided with a check valve, which is located between the pressure fine adjustment device and the vent pipeline. The check valve is used to maintain the one-way flow of gas from the main pipeline to the vent pipeline from the branch pipeline.

[0018] In one specific embodiment, along the gas flow direction within the main pipeline, a first pressure coarse adjustment device, a first pressure sensing device, a second pressure coarse adjustment device, and a second pressure sensing device are sequentially provided on the main pipeline. A first branch pipeline extends between the first pressure coarse adjustment device and the first pressure sensing device. A first pressure fine adjustment device and a first check valve are sequentially provided on the first branch pipeline. A second branch pipeline extends between the second pressure coarse adjustment device and the second pressure sensing device. A second pressure fine adjustment device and a second check valve are sequentially provided on the second branch pipeline.

[0019] This invention also provides a method for regulating the pressure of hydrogen-blended natural gas in a confined space. The method employs a hydrogen-blended natural gas pressure regulating system with primary pressure regulating function as described above. The method includes the following steps:

[0020] The gas pressure in the main pipeline is adjusted according to the target preset pressure range using the pressure coarse adjustment device.

[0021] After the pressure coarse adjustment device is adjusted, the pressure signal of the pressure sensing device is acquired. When the pressure coarse adjustment device is adjusted to the correct position, the pressure-adjusted hydrogen-blended natural gas is introduced into the experimental area. If the pressure coarse adjustment device is not adjusted to the correct position, the pressure signal is compared with the first preset pressure range.

[0022] When the pressure signal from the pressure sensor is higher than the maximum value of the first preset pressure range, the pressure coarse adjustment device is controlled to increase its opening to adjust the gas pressure in the main pipeline to the target preset pressure range; or, when the pressure signal from the pressure sensor is lower than the minimum value of the first preset pressure range, the pressure coarse adjustment device is controlled to decrease its opening to adjust the gas pressure in the main pipeline to the target preset pressure range; or, when the pressure signal from the pressure sensor is within the first preset pressure range, the pressure fine adjustment device is controlled to increase or decrease its opening based on the positive or negative difference between the pressure signal and the target preset pressure range to adjust and maintain the gas pressure in the main pipeline within the target preset pressure range.

[0023] When the pressure signal from the pressure sensing device is again within the target preset pressure range, the pressure-regulated hydrogen-blended natural gas is introduced into the experimental area.

[0024] This invention also provides a method for regulating the pressure of hydrogen-blended natural gas in a confined space. The method employs a hydrogen-blended natural gas pressure regulating system with two-stage pressure regulating function as described above. The method includes the following steps:

[0025] The gas pressure in the main pipeline is adjusted according to the target preset pressure range using the first pressure coarse adjustment device.

[0026] After the first pressure coarse adjustment device completes the adjustment, the pressure signal of the first pressure sensor is acquired. When the first pressure coarse adjustment device is in place, the pressure-adjusted hydrogen-blended natural gas is introduced into the experimental area. If the first pressure coarse adjustment device is not in place, the pressure signal is compared with the first preset pressure range.

[0027] When the pressure signal from the first pressure sensor is higher than the maximum value of the first preset pressure range, the first pressure coarse adjustment device is controlled to increase its opening to adjust the gas pressure in the main pipeline to the target preset pressure range; or, when the pressure signal from the first pressure sensor is lower than the minimum value of the first preset pressure range, the first pressure coarse adjustment device is controlled to decrease its opening to adjust the gas pressure in the main pipeline to the target preset pressure range; or, when the pressure signal from the first pressure sensor is within the first preset pressure range, the first pressure fine adjustment device is controlled to increase or decrease its opening based on the positive or negative difference between the pressure signal and the target preset pressure range to adjust and maintain the gas pressure in the main pipeline within the target preset pressure range.

[0028] After the first pressure fine-tuning device completes the adjustment, when the pressure signal of the first pressure sensor is within the target preset pressure range, the pressure signal of the second pressure sensor is acquired. When the gas pressure of the main pipeline is stable within the target preset pressure range, the pressure-regulated hydrogen-blended natural gas is introduced into the experimental area. When the gas pressure of the main pipeline fluctuates outside the target preset pressure range, the pressure signal is compared with the second preset pressure range.

[0029] When the pressure signal from the second pressure sensor is higher than the maximum value of the second preset pressure range, the second pressure coarse adjustment device is controlled to increase its opening to adjust the gas pressure in the main pipeline to the target preset pressure range; or, when the pressure signal from the second pressure sensor is lower than the minimum value of the first preset pressure range, the second pressure coarse adjustment device is controlled to decrease its opening to adjust the gas pressure in the main pipeline to the target preset pressure range; or, when the pressure signal from the second pressure sensor is within the second preset pressure range, the second pressure fine adjustment device is controlled to increase or decrease its opening based on the positive or negative difference between the pressure signal and the target preset pressure range to adjust and maintain the gas pressure in the main pipeline within the target preset pressure range.

[0030] When the pressure signal from the second pressure sensor is again within the target preset pressure range, the pressure-regulated hydrogen-blended natural gas is introduced into the experimental area.

[0031] The features and advantages of this invention are:

[0032] 1. The hydrogen-blended natural gas pressure regulating system of the present invention achieves automated gas pressure detection, regulation and stabilization in one step by setting up a pressure regulating device and a detection device that are electrically connected to the control system.

[0033] 2. The hydrogen-blended natural gas pressure regulating system of the present invention has high space utilization, reduces the space requirements of the hydrogen-blended natural gas experimental system, and simplifies the design of system construction.

[0034] 3. The hydrogen-blended natural gas pressure regulating system of the present invention can guide the modification of existing experimental systems and improve the safety of experimental systems without introducing new high-risk equipment such as pressure vessels. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the composition of the hydrogen-blended natural gas pressure regulating system with primary pressure regulating function according to the present invention;

[0037] Figure 2 This is a schematic diagram of the hydrogen-blended natural gas pressure regulating system with two-stage pressure regulating function according to the present invention;

[0038] Figure 3 This is a flowchart illustrating the pressure regulation process of the hydrogen-blended natural gas pressure regulation system with primary pressure regulation function according to the present invention.

[0039] Explanation of icon numbers:

[0040] 1. Main pipeline; 2. Control system; 3. Vent pipeline; 4. First pressure coarse adjustment device; 5. First pressure sensor; 6. Second pressure coarse adjustment device; 7. Second pressure sensor; 8. First branch pipeline; 9. First pressure fine adjustment device; 10. First check valve; 11. Second branch pipeline; 12. Second pressure fine adjustment device; 13. Second check valve. Detailed Implementation

[0041] 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.

[0042] like Figure 1 and Figure 2As shown, this invention provides a hydrogen-blended natural gas pressure regulating system in a confined space, comprising: a main pipeline 1, located between a gas source and an experimental zone, along the gas flow direction within the main pipeline 1, i.e., from the gas source to the experimental zone; the main pipeline 1 is sequentially equipped with at least one pressure coarse adjustment device and at least one pressure sensing device; the pressure coarse adjustment device is used to adjust the gas pressure flowing into the main pipeline 1 to a target preset pressure range; the pressure sensing device is used to detect the pressure of the gas entering the experimental zone via the main pipeline 1; and at least one branch pipeline, one end of which is connected to the pressure coarse adjustment device and the pressure sensing device. On the main pipeline 1 connecting the force sensing devices, branch pipelines are equipped with pressure fine-tuning devices for adjusting and maintaining the gas pressure within the main pipeline 1 within a target preset pressure range. Control system 2 is electrically connected to the pressure coarse-tuning device, pressure sensing device, and pressure fine-tuning device to automatically detect and regulate the gas pressure in the main pipeline 1. When the pressure coarse-tuning device fails to adjust the gas pressure in the main pipeline 1 to the target preset pressure range, control system 2 controls the pressure fine-tuning device to fine-tune the gas pressure within the main pipeline 1, ensuring the gas pressure in the main pipeline 1 remains stable within the target preset pressure range. The pressure coarse-tuning device can be an electrically controlled pressure regulating valve, the pressure sensing device can be an electrical sensor, and the pressure fine-tuning device can be an electromagnetic shut-off valve. Specifically, when only one pressure sensing device is installed on the main pipeline 1, it is located at the end of the main pipeline 1 near the experimental area.

[0043] In some embodiments listed in this application, the hydrogen-blended natural gas pressure regulating system is mainly illustrated by including a two-stage pressure coarse adjustment device, two pressure sensing devices, and two branch pipelines. Of course, in other embodiments, the hydrogen-blended natural gas pressure regulating system can include more stages, such as a three-stage pressure coarse adjustment device, three pressure sensing devices, and three branch pipelines combined to form a hydrogen-blended natural gas pressure regulating system with three-stage pressure regulating function; alternatively, it can include a single-stage pressure coarse adjustment device, one pressure sensing device, and one branch pipeline combined to form a hydrogen-blended natural gas pressure regulating system with single-stage pressure regulating function. Specifically, the system can be adaptively configured based on the gas pressure maintenance situation in the pipeline after the initial pressure adjustment to the target preset range.

[0044] To facilitate flexible control of the gas pressure of the main pipeline 1 by the control system 2, the control system 2 is equipped with a first preset pressure range, a second preset pressure range, and a target preset pressure range according to the gas pressure adjustment process of the main pipeline 1. The first preset pressure range and the second preset pressure range do not overlap with the target preset pressure range. The first preset pressure range and the second preset pressure range can be the same, different, or partially the same. This invention does not impose any restrictions on this.

[0045] According to one embodiment of the present invention, when the pressure signal from the pressure sensing device feedback control system 2 is outside the first preset pressure range, that is, when the pressure coarse adjustment device fails to adjust the gas pressure of the main pipeline 1 to the first preset pressure range, the control system 2 controls the pressure coarse adjustment device to adjust the gas pressure in the main pipeline 1 with the target preset pressure range as the target; when the pressure signal from the pressure sensing device feedback control system 2 is within the first preset pressure range, that is, when the pressure coarse adjustment device adjusts the gas pressure in the main pipeline 1 to the first preset pressure range, the control system 2 controls the pressure fine adjustment device to finely adjust the gas pressure in the main pipeline 1 with the target preset pressure range as the target, so that the gas pressure in the main pipeline 1 is stabilized within the target preset pressure range.

[0046] Furthermore, the first preset pressure range may include multiple preset pressure intervals, such as a first preset pressure interval and a second preset pressure interval. The minimum value of the first preset pressure interval is greater than the maximum value of the target preset pressure range, and the maximum value of the second preset pressure interval is less than the minimum value of the target preset pressure range. That is, the target preset pressure range is a closed interval, the first preset pressure interval is a left-open and right-closed interval, and the second preset pressure interval is a left-closed and right-open interval. When the pressure signal from the pressure sensor to the control system 2 is within the first preset pressure range, that is, when the first coarse pressure adjustment device 4 adjusts the gas pressure in the main pipeline 1 to the first preset pressure range, the control system 2 controls the fine pressure adjustment device to increase its opening to finely adjust the gas pressure in the main pipeline 1, so that the gas pressure in the main pipeline 1 is stabilized within the target preset pressure range; when the pressure signal from the pressure sensor to the control system 2 is within the second preset pressure range, that is, when the coarse pressure adjustment device adjusts the gas pressure in the main pipeline 1 to the second preset pressure range, the control system 2 controls the fine pressure adjustment device to decrease its opening to finely adjust the gas pressure in the main pipeline 1, so that the gas pressure in the main pipeline 1 is stabilized within the target preset pressure range.

[0047] According to one embodiment of the present invention, a multi-stage pressure coarse adjustment device and multiple pressure sensing devices are provided on the main pipeline 1. Along the gas flow direction within the main pipeline 1, the multi-stage pressure coarse adjustment device and the multiple pressure sensing devices are arranged alternately and sequentially. In this way, the multi-stage pressure coarse adjustment device provides multi-level adjustable conditions for gas pressure regulation within the main pipeline 1, while simultaneously preventing pressure fluctuations in the pipeline section leading to the experimental area from affecting the experiment. Specifically, the pressure sensing device can be one located on the main pipeline 1 before entering the experimental area, or multiple devices can be correspondingly located after the multi-stage pressure coarse adjustment device; the present invention does not limit this.

[0048] Furthermore, the hydrogen-blended natural gas pressure regulating system includes multiple branch pipelines, one end of each branch pipeline being connected to the main pipeline 1 between adjacent pressure coarse adjustment devices and pressure sensing devices. Through these corresponding branch pipelines, the corresponding fine adjustment is achieved when the pressure coarse adjustment device of the same level regulates the gas pressure of the main pipeline 1 to a first preset pressure range. The pressure sensing device installed after each branch pipeline allows for the detection and feedback of multiple adjustments by the same pressure sensing device to the pressure coarse and fine adjustment devices located upstream of it, reducing the number of devices required and improving utilization. Specifically, the branch pipelines can be multiple pipelines corresponding to multiple pressure coarse adjustment devices, multiple pipelines spaced apart after the same level pressure coarse adjustment device, or a single pipeline after multiple levels of pressure coarse adjustment devices; this invention does not limit the specific branch pipelines.

[0049] According to one embodiment of the present invention, the hydrogen-blended natural gas pressure regulating system further includes a venting pipeline 3, which is connected to the other end of a branch pipeline. That is, the main pipeline 1 is connected to the venting pipeline 3 via a branch pipeline, and a venting system is connected to the venting pipeline 3. By introducing a venting system instead of a buffer tank, the safety of the experimental system is improved. In this embodiment, the venting pipeline 3 is also connected to the experimental area.

[0050] According to one embodiment of the present invention, each branch pipeline is equipped with a check valve, which is located between the pressure fine-tuning device and the vent pipeline 3. The check valve is used to maintain the one-way flow of gas from the main pipeline 1 to the vent pipeline 3 from the branch pipeline. In this embodiment, the check valve is a one-way valve.

[0051] According to one embodiment of the present invention, along the gas flow direction within the main pipeline 1, a first pressure coarse adjustment device 4, a first pressure sensing device 5, a second pressure coarse adjustment device 6, and a second pressure sensing device 7 are sequentially provided on the main pipeline 1. A first branch pipeline 8 is led out between the first pressure coarse adjustment device 4 and the first pressure sensing device 5. Along the gas flow direction within the first branch pipeline 8, a first pressure fine adjustment device 9 and a first check valve 10 are sequentially provided on the first branch pipeline 8. A second branch pipeline 11 is led out between the second pressure coarse adjustment device 6 and the second pressure sensing device 7. Along the gas flow direction within the second branch pipeline 11, a second pressure fine adjustment device 12 and a second check valve 13 are sequentially provided on the second branch pipeline 11.

[0052] Based on the above description, the hydrogen-blended natural gas pressure regulating system of the present invention has the following beneficial effects:

[0053] The hydrogen-blended natural gas pressure regulating system provided by this invention automates gas pressure detection, regulation, and stabilization in one step by setting up a pressure regulating device and a detection device electrically connected to the control system 2. The system offers high space utilization, reducing the space requirements of the hydrogen-blended natural gas experimental system and simplifying system design. Furthermore, it can guide the modification of existing experimental systems without introducing new high-risk equipment such as pressure vessels, improving system safety. In addition, the system reduces the number of pressure sensors required and increases utilization by using pressure sensors corresponding to branch pipelines.

[0054] See also Figure 3 As shown, the present invention also provides a method for regulating the pressure of hydrogen-blended natural gas in a confined space, which is implemented using a hydrogen-blended natural gas pressure regulating system with primary pressure regulating function as described above. This method includes the following steps:

[0055] Step S1: Use the pressure coarse adjustment device to adjust the gas pressure of the main pipeline 1 according to the target preset pressure range.

[0056] Step S2: After the pressure coarse adjustment device is adjusted, the pressure signal of the pressure sensor is obtained. When the pressure coarse adjustment device is adjusted to the correct position, the pressure-adjusted hydrogen-blended natural gas is introduced into the experimental area. If the pressure coarse adjustment device is not adjusted to the correct position, the pressure signal is compared with the first preset pressure range.

[0057] Step S3: When the pressure signal from the pressure sensor is higher than the maximum value of the first preset pressure range, control the pressure coarse adjustment device to increase its opening to adjust the gas pressure of the main pipeline 1 to the target preset pressure range; or, when the pressure signal from the pressure sensor is lower than the minimum value of the first preset pressure range, control the pressure coarse adjustment device to decrease its opening to adjust the gas pressure of the main pipeline 1 to the target preset pressure range; or, when the pressure signal from the pressure sensor is within the first preset pressure range, control the pressure fine adjustment device to increase or decrease its opening based on the positive or negative difference between the pressure signal and the target preset pressure range to adjust and maintain the gas pressure of the main pipeline 1 within the target preset pressure range.

[0058] Step S4: When the pressure signal from the pressure sensor is again within the target preset pressure range, pressurized hydrogen-blended natural gas is introduced into the experimental area.

[0059] In step S3: When the pressure signal detected by the pressure sensor and fed back to the control system 2 is higher than the maximum value of the preset pressure range, it indicates that the pressure coarse adjustment device is not reducing the pressure sufficiently, and a positive difference is formed between the acquired pressure signal and the target preset pressure range. The control system 2 controls the pressure coarse adjustment device to increase its opening to adjust the gas pressure of the main pipeline 1 to the target preset pressure range. When the pressure signal detected by the pressure sensor and fed back to the control system 2 is lower than the minimum value of the first preset pressure range, it indicates that the pressure coarse adjustment device is reducing the pressure excessively, and a negative difference is formed between the acquired pressure signal and the target preset pressure range. The control system 2 controls the pressure coarse adjustment device to decrease its opening to adjust the gas pressure of the main pipeline 1 to the target preset pressure range. When the pressure signal detected by the pressure sensor and fed back to the control system 2 is within the first preset pressure range, it indicates that the pressure coarse adjustment device is reducing the pressure excessively, and a negative difference is formed between the acquired pressure signal and the target preset pressure range. The control system 2 controls the pressure coarse adjustment device to decrease its opening to adjust the gas pressure of the main pipeline 1 to the target preset pressure range. When the pressure signal is within the target preset pressure range, i.e., when a positive difference is formed between the pressure signal and the target preset pressure range, it indicates that the gas under-expanded after being reduced by the pressure coarse adjustment device. The gas in the main pipeline 1 continues to expand, causing the pressure to rise. The control system 2 controls the pressure fine adjustment device to increase the opening, allowing a large amount of expanded gas to enter the vent pipeline 3, so as to regulate and maintain the gas pressure in the main pipeline 1 within the target preset pressure range. When the pressure sensor detects that the pressure signal fed back to the control system 2 is in the second preset pressure range of the first preset pressure range, i.e., when a negative difference is formed between the pressure signal and the target preset pressure range, it indicates that the gas over-expanded after being adjusted by the pressure fine adjustment device or that the gas volume required in the experimental area has increased. The control system 2 controls the pressure fine adjustment device to decrease the opening, allowing a small amount of expanded gas to enter the vent pipeline 3, so as to regulate and maintain the gas pressure in the main pipeline 1 within the target preset pressure range.

[0060] This invention also provides a method for regulating the pressure of hydrogen-blended natural gas in a confined space, which is implemented using a hydrogen-blended natural gas pressure regulating system with two-stage pressure regulating function as described above. The method for regulating the pressure of hydrogen-blended natural gas includes the following steps:

[0061] Step S1: Use the first pressure coarse adjustment device 4 to adjust the gas pressure of the main pipeline 1 according to the target preset pressure range.

[0062] Step S2: After the first pressure coarse adjustment device 4 is adjusted, the pressure signal of the first pressure sensing device 5 is obtained. When the first pressure coarse adjustment device 4 is adjusted to the correct position, the pressure-adjusted hydrogen-blended natural gas is introduced into the experimental area. If the first pressure coarse adjustment device 4 is not adjusted to the correct position, the pressure signal is compared with the first preset pressure range.

[0063] Step S3: When the pressure signal from the first pressure sensor 5 is higher than the maximum value of the first preset pressure range, control the first pressure coarse adjustment device 4 to increase its opening to adjust the gas pressure of the main pipeline 1 to the target preset pressure range; or, when the pressure signal from the first pressure sensor 5 is lower than the minimum value of the first preset pressure range, control the first pressure coarse adjustment device 4 to decrease its opening to adjust the gas pressure of the main pipeline 1 to the target preset pressure range; or, when the pressure signal from the first pressure sensor 5 is within the first preset pressure range, control the first pressure fine adjustment device 9 to increase or decrease its opening based on the positive or negative difference between the pressure signal and the target preset pressure range to adjust and maintain the gas pressure of the main pipeline 1 within the target preset pressure range.

[0064] Step S4: After the first pressure fine-tuning device 9 has finished adjusting, when the pressure signal of the first pressure sensing device 5 is within the target preset pressure range, the pressure signal of the second pressure sensing device 7 is obtained. When the gas pressure of the main pipeline 1 is stable within the target preset pressure range, the pressure-regulated hydrogen-doped natural gas is introduced into the experimental area. When the gas pressure of the main pipeline 1 fluctuates outside the target preset pressure range, the pressure signal is compared with the second preset pressure range.

[0065] Step S5: When the pressure signal from the second pressure sensor 7 is higher than the maximum value of the second preset pressure range, control the second pressure coarse adjustment device 6 to increase its opening to adjust the gas pressure of the main pipeline 1 to the target preset pressure range; or, when the pressure signal from the second pressure sensor 7 is lower than the minimum value of the first preset pressure range, control the second pressure coarse adjustment device 6 to decrease its opening to adjust the gas pressure of the main pipeline 1 to the target preset pressure range; or, when the pressure signal from the second pressure sensor 7 is within the second preset pressure range, control the second pressure fine adjustment device 12 to increase or decrease its opening based on the positive or negative difference between the pressure signal and the target preset pressure range to adjust and maintain the gas pressure of the main pipeline 1 within the target preset pressure range.

[0066] Step S6: When the pressure signal from the second pressure sensor 7 is again within the target preset pressure range, pressurized hydrogen-blended natural gas is introduced into the experimental area. In Step S3: When the pressure signal detected by the first pressure sensor 5 and fed back to the control system 2 is higher than the maximum value of the first preset pressure range, it indicates that the first pressure coarse adjustment device 4 has not reduced the pressure sufficiently, and a positive difference is formed between the acquired pressure signal and the target preset pressure range. The control system 2 controls the first pressure coarse adjustment device 4 to increase its opening to adjust the gas pressure of the main pipeline 1 to the target preset pressure range; when the pressure signal detected by the first pressure sensor 5 and fed back to the control system 2 is lower than the minimum value of the first preset pressure range, it indicates that the first pressure coarse adjustment device 4 has reduced the pressure excessively, and a negative difference is formed between the acquired pressure signal and the target preset pressure range. The control system 2 controls the first pressure coarse adjustment device 4 to decrease its opening to adjust the gas pressure of the main pipeline 1 to the target preset pressure range; when the first pressure sensor 5 detects feedback... When the pressure signal from the control system 2 is within the first preset pressure range, it indicates that the gas under-expanded after being reduced in pressure by the first pressure coarse adjustment device 4. The gas in the main pipeline 1 continues to expand, causing the pressure to rise. The control system 2 controls the first pressure fine adjustment device 9 to increase its opening, allowing a large amount of expanded gas to enter the vent pipeline 3, so as to regulate and maintain the gas pressure in the main pipeline 1 within the target preset pressure range. When the pressure signal from the first pressure sensor 5 is detected and fed back to the control system 2 within the second preset pressure range, it indicates that the gas over-expanded after being adjusted by the first pressure fine adjustment device 9 or that the gas volume required in the experimental area has increased. The control system 2 controls the first pressure fine adjustment device 9 to decrease its opening, allowing a small amount of expanded gas to enter the vent pipeline 3, so as to regulate and maintain the gas pressure in the main pipeline 1 within the target preset pressure range.

[0067] In step S5: When the second pressure sensor 7 detects a pressure signal fed back to the control system 2 that is higher than the maximum value of the second preset pressure range, it indicates that the gas in the main pipeline 1 is under-expanded in the pipeline section after the first pressure sensor 5. The control system 2 controls the second pressure coarse adjustment device 6 to increase its opening to adjust the gas pressure in the main pipeline 1 to the target preset pressure range. When the second pressure sensor 7 detects a pressure signal fed back to the control system 2 that is lower than the minimum value of the second preset pressure range, it indicates that the gas in the main pipeline 1 is over-expanded in the pipeline section after the first pressure sensor 5 or that the required gas volume in the experimental area has increased. The control system 2 controls the second pressure coarse adjustment device 6 to decrease its opening to adjust the gas pressure in the main pipeline 1 to the target preset pressure range. When the second pressure sensor 7 detects a pressure signal fed back to the control system 2 that is lower than the minimum value of the second preset pressure range, it indicates that the gas in the main pipeline 1 is over-expanded in the pipeline section after the first pressure sensor 5 or that the required gas volume in the experimental area has increased. The control system 2 controls the second pressure coarse adjustment device 6 to decrease its opening to adjust the gas pressure in the main pipeline 1 to the target preset pressure range. When the pressure signal is within the first preset pressure range of the second preset pressure range, it indicates that the gas under-expanded after being reduced in pressure by the second pressure coarse adjustment device 6. The gas in the main pipeline 1 continues to expand, causing the pressure to rise. The control system 2 controls the second pressure fine adjustment device 12 to increase its opening, allowing a large amount of expanded gas to enter the vent pipeline 3, thereby regulating and maintaining the gas pressure in the main pipeline 1 within the target preset pressure range. When the pressure signal detected by the second pressure sensor 7 and fed back to the control system 2 is within the second preset pressure range of the second preset pressure range, it indicates that the gas over-expanded after being adjusted by the second pressure fine adjustment device 12, or that the required gas volume in the experimental area has increased. The control system 2 controls the second pressure fine adjustment device 12 to decrease its opening, allowing a small amount of expanded gas to enter the vent pipeline 3, thereby regulating and maintaining the gas pressure in the main pipeline 1 within the target preset pressure range. The minimum value of the first preset pressure range of the second preset pressure range is greater than the maximum value of the target preset pressure range, and the maximum value of the second preset pressure range of the second preset pressure range is less than the minimum value of the target preset pressure range. The second preset pressure range can be the same as or different from the first preset pressure range.In this embodiment, taking the hydrogen-blended natural gas atmospheric pressure (1 kPa) experiment as an example, the target preset pressure range is ±5% of the experimental pressure, i.e., [0.95 kPa, 1.05 kPa]; the first preset pressure range is ±10% to ±30% of the experimental pressure, i.e., (1.1 kPa, 1.3 kPa] ∪ [0.7 kPa, 0.9 kPa); the first preset pressure interval of the first preset pressure range is 10% to 30% of the experimental pressure, i.e., (1.1 kPa, 1.3 kPa]; the second preset pressure interval of the first preset pressure range is the experimental pressure... The first preset pressure range is ±30% to ±10% of the experimental pressure, i.e., [0.7 kPa, 0.9 kPa); the second preset pressure range is ±5% to ±15% of the experimental pressure, i.e., (1.05 kPa, 1.15 kPa] ∪ [0.85 kPa, 0.95 kPa); the first preset pressure interval of the second preset pressure range is 5% to 15% of the experimental pressure, i.e., (1.05 kPa, 1.15 kPa); the second preset pressure interval of the second preset pressure range is -15% to -5% of the experimental pressure, i.e., [0.85 kPa, 0.95 kPa).

[0068] The above descriptions are merely a few embodiments of the present invention. Those skilled in the art can make various modifications or variations to the embodiments of the present invention based on the content disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A hydrogen-blended natural gas pressure regulating system in a confined space, characterized in that, include: A main pipeline is used to be located between the gas source and the experimental area. Along the gas flow direction in the main pipeline, at least one pressure coarse adjustment device and at least one pressure sensing device are sequentially provided on the main pipeline. The pressure coarse adjustment device is used to adjust the gas pressure flowing into the main pipeline to a target preset pressure range, and the pressure sensing device is used to detect the pressure of the gas entering the experimental area through the main pipeline. At least one branch pipeline, one end of which is connected to the main pipeline between the pressure coarse adjustment device and the pressure sensing device, and the branch pipeline is provided with a pressure fine adjustment device, which is used to adjust and maintain the gas pressure in the main pipeline within a target preset pressure range. The control system is electrically connected to the pressure coarse adjustment device, the pressure sensing device, and the pressure fine adjustment device. When the pressure coarse adjustment device fails to adjust the gas pressure in the main pipeline to the target preset pressure range, the control system controls the pressure fine adjustment device to perform pressure fine adjustment on the gas in the main pipeline. When the pressure coarse adjustment device fails to adjust the gas pressure in the main pipeline to the first preset pressure range, the control system controls the pressure coarse adjustment device to adjust the gas pressure in the main pipeline; when the pressure coarse adjustment device adjusts the gas pressure in the main pipeline to the first preset pressure range, the control system controls the pressure fine adjustment device to fine adjust the gas pressure in the main pipeline. The first preset pressure range includes a first preset pressure interval and a second preset pressure interval. The minimum value of the first preset pressure interval is greater than the maximum value of the target preset pressure range, and the maximum value of the second preset pressure interval is less than the minimum value of the target preset pressure range. When the coarse pressure adjustment device adjusts the gas pressure in the main pipeline to the first preset pressure range, the control system controls the fine pressure adjustment device to increase its opening to finely adjust the gas pressure in the main pipeline, so that the gas pressure in the main pipeline is within the target preset pressure range; when the coarse pressure adjustment device adjusts the gas pressure in the main pipeline to the second preset pressure range, the control system controls the fine pressure adjustment device to decrease its opening to finely adjust the gas pressure in the main pipeline, so that the gas pressure in the main pipeline is within the target preset pressure range.

2. The hydrogen-blended natural gas pressure regulating system according to claim 1, characterized in that, The main pipeline is equipped with a multi-stage pressure coarse adjustment device and multiple pressure sensing devices. Along the gas flow direction in the main pipeline, the multi-stage pressure coarse adjustment device and multiple pressure sensing devices are arranged alternately and at intervals.

3. The hydrogen-blended natural gas pressure regulating system according to claim 2, characterized in that, The hydrogen-blended natural gas pressure regulating system includes multiple branch pipelines, one end of each branch pipeline being connected to the main pipeline between the adjacent pressure coarse adjustment device and the pressure sensing device.

4. The hydrogen-blended natural gas pressure regulating system according to claim 1 or 3, characterized in that, The hydrogen-blended natural gas pressure regulating system also includes a venting pipeline, which is connected to the other end of the branch pipeline, and a venting system is connected to the venting pipeline.

5. The hydrogen-blended natural gas pressure regulating system according to claim 4, characterized in that, Each of the branch pipelines is equipped with a check valve, which is located between the pressure fine-tuning device and the vent pipeline. The check valve is used to maintain the one-way flow of gas from the main pipeline to the vent pipeline from the branch pipeline.

6. The hydrogen-blended natural gas pressure regulating system according to claim 5, characterized in that, Along the gas flow direction within the main pipeline, a first pressure coarse adjustment device, a first pressure sensing device, a second pressure coarse adjustment device, and a second pressure sensing device are sequentially provided on the main pipeline. A first branch pipeline is led out between the first pressure coarse adjustment device and the first pressure sensing device. A first pressure fine adjustment device and a first check valve are sequentially provided on the first branch pipeline. A second branch pipeline is led out between the second pressure coarse adjustment device and the second pressure sensing device. A second pressure fine adjustment device and a second check valve are sequentially provided on the second branch pipeline.

7. A method for pressure regulation of hydrogen-blended natural gas in a confined space, characterized in that, The hydrogen-blended natural gas pressure regulation method is implemented using the hydrogen-blended natural gas pressure regulation system as described in claim 1, and the hydrogen-blended natural gas pressure regulation method includes the following steps: The gas pressure in the main pipeline is adjusted according to the target preset pressure range using the pressure coarse adjustment device. After the pressure coarse adjustment device is adjusted, the pressure signal of the pressure sensing device is acquired. When the pressure coarse adjustment device is adjusted to the correct position, the pressure-adjusted hydrogen-blended natural gas is introduced into the experimental area. If the pressure coarse adjustment device is not adjusted to the correct position, the pressure signal is compared with the first preset pressure range. When the pressure signal from the pressure sensor is higher than the maximum value of the first preset pressure range, the pressure coarse adjustment device is controlled to increase its opening to adjust the gas pressure in the main pipeline to the target preset pressure range; or, when the pressure signal from the pressure sensor is lower than the minimum value of the first preset pressure range, the pressure coarse adjustment device is controlled to decrease its opening to adjust the gas pressure in the main pipeline to the target preset pressure range; or, when the pressure signal from the pressure sensor is within the first preset pressure range, the pressure fine adjustment device is controlled to increase or decrease its opening based on the positive or negative difference between the pressure signal and the target preset pressure range to adjust and maintain the gas pressure in the main pipeline within the target preset pressure range. When the pressure signal from the pressure sensing device is again within the target preset pressure range, the pressure-regulated hydrogen-blended natural gas is introduced into the experimental area.

8. A method for pressure regulation of hydrogen-blended natural gas in a confined space, characterized in that, The hydrogen-blended natural gas pressure regulation method is implemented using the hydrogen-blended natural gas pressure regulation system as described in claim 6, and the hydrogen-blended natural gas pressure regulation method includes the following steps: The gas pressure in the main pipeline is adjusted according to the target preset pressure range using the first pressure coarse adjustment device. After the first pressure coarse adjustment device completes the adjustment, the pressure signal of the first pressure sensor is acquired. When the first pressure coarse adjustment device is in place, the pressure-adjusted hydrogen-blended natural gas is introduced into the experimental area. If the first pressure coarse adjustment device is not in place, the pressure signal is compared with the first preset pressure range. When the pressure signal from the first pressure sensor is higher than the maximum value of the first preset pressure range, the first pressure coarse adjustment device is controlled to increase its opening to adjust the gas pressure in the main pipeline to the target preset pressure range; or, when the pressure signal from the first pressure sensor is lower than the minimum value of the first preset pressure range, the first pressure coarse adjustment device is controlled to decrease its opening to adjust the gas pressure in the main pipeline to the target preset pressure range; or, when the pressure signal from the first pressure sensor is within the first preset pressure range, the first pressure fine adjustment device is controlled to increase or decrease its opening based on the positive or negative difference between the pressure signal and the target preset pressure range to adjust and maintain the gas pressure in the main pipeline within the target preset pressure range. After the first pressure fine-tuning device completes the adjustment, when the pressure signal of the first pressure sensor is within the target preset pressure range, the pressure signal of the second pressure sensor is acquired. When the gas pressure of the main pipeline is stable within the target preset pressure range, the pressure-regulated hydrogen-blended natural gas is introduced into the experimental area. When the gas pressure of the main pipeline fluctuates outside the target preset pressure range, the pressure signal is compared with the second preset pressure range. When the pressure signal from the second pressure sensor is higher than the maximum value of the second preset pressure range, the second pressure coarse adjustment device is controlled to increase its opening to adjust the gas pressure in the main pipeline to the target preset pressure range; or, when the pressure signal from the second pressure sensor is lower than the minimum value of the first preset pressure range, the second pressure coarse adjustment device is controlled to decrease its opening to adjust the gas pressure in the main pipeline to the target preset pressure range; or, when the pressure signal from the second pressure sensor is within the second preset pressure range, the second pressure fine adjustment device is controlled to increase or decrease its opening based on the positive or negative difference between the pressure signal and the target preset pressure range to adjust and maintain the gas pressure in the main pipeline within the target preset pressure range. When the pressure signal from the second pressure sensor is again within the target preset pressure range, the pressure-regulated hydrogen-blended natural gas is introduced into the experimental area.

Images