CN-117906062-B - Hydrogen-doped natural gas pressure regulating system and method in limited space

CN117906062BCN 117906062 BCN117906062 BCN 117906062BCN-117906062-B

Abstract

The invention discloses a pressure regulating system and a pressure regulating method for hydrogen-doped natural gas in a limited space, and relates to the field of gas pressure control, wherein the system comprises a main pipeline, a pressure regulating device and a pressure sensing device, wherein the main pipeline is arranged between a gas source and an experiment area, and is sequentially provided with at least one level of pressure rough regulating device and at least one pressure sensing device for detecting the pressure of the gas entering the experiment area through the main pipeline along the gas flowing direction in the main pipeline; the control system controls the pressure fine-tuning device to act to fine-tune the gas pressure in the main pipeline so as to maintain the gas pressure in the main pipeline in a target preset pressure range when the pressure coarse-tuning device does not adjust the gas pressure in the main pipeline to the target preset pressure range. Therefore, the automatic regulation and control of the pressure of the hydrogen-doped natural gas are realized while the space utilization rate and the system safety are improved.

Inventors

DONG SHAOHUA
Han Zicong
CHEN LIN
XU QINGQING
REN JIE
WU HAOZHI
SUN MENG

Assignees

中国石油大学(北京)

Dates

Publication Date: 20260505
Application Date: 20240124

Claims (8)

1. A hydrogen-loaded natural gas pressure regulating system in a confined space, comprising: The main pipeline is arranged between an air source and an experiment area, at least one level of pressure rough adjusting device and at least one pressure sensing device are sequentially arranged on the main pipeline along the air flow direction in the main pipeline, the pressure rough adjusting device is used for adjusting the pressure of air flowing into the main pipeline to a target preset pressure range, and the pressure sensing device is used for detecting the pressure of air entering the experiment area through the main pipeline; one end of the branch pipeline is communicated with a main pipeline between the pressure coarse adjusting device and the pressure sensing device, and the branch pipeline is provided with a pressure fine adjusting device which is used for adjusting and maintaining the gas pressure in the main pipeline within a target preset pressure range; The control system is electrically connected with the pressure rough adjusting device, the pressure sensing device and the pressure fine adjusting device, and when the pressure rough adjusting device does not adjust the gas pressure of the main pipeline to the target preset pressure range, the control system controls the pressure fine adjusting device to act to carry out pressure fine adjustment on the gas in the main pipeline; When the pressure rough adjusting device adjusts the gas pressure of the main pipeline to a first preset pressure range, the control system controls the pressure fine adjusting device to move to carry out pressure fine adjustment on the gas in the main pipeline; The control system controls the pressure fine adjustment device to increase the opening degree to carry out pressure fine adjustment on the gas in the main pipeline when the pressure coarse adjustment device adjusts the gas pressure of the main pipeline to the first preset pressure interval of the first preset pressure range, so that the gas pressure in the main pipeline is in the target preset pressure range, and controls the pressure fine adjustment device to decrease the opening degree to carry out pressure fine adjustment on the gas in the main pipeline when the pressure coarse adjustment device adjusts the gas pressure of the main pipeline to the second preset pressure interval of the first preset pressure range, so that the gas pressure in the main pipeline is in the target preset pressure range.
2. The hydrogen-doped natural gas pressure regulating system according to claim 1, wherein the main pipeline is provided with a multi-stage pressure coarse regulating device and a plurality of pressure sensing devices, and the multi-stage pressure coarse regulating device and the plurality of pressure sensing devices are sequentially staggered at intervals along the gas flow direction in the main pipeline.
3. The hydrogen-loaded natural gas pressure regulating system of claim 2, wherein the hydrogen-loaded natural gas pressure regulating system comprises a plurality of branch pipelines, one end of each branch pipeline is communicated with a main pipeline between the adjacent pressure rough adjusting device and the pressure sensing device in a one-to-one correspondence manner.
4. The hydrogen-loaded natural gas pressure regulating system of claim 1 or 3, further comprising a vent line, wherein the vent line is in communication with the other end of the branch line, and wherein the vent line is connected to a vent system.
5. The hydrogen-loaded natural gas pressure regulating system of claim 4, wherein each of the branch lines is provided with a check valve disposed between the pressure fine regulating device and the vent line, the check valve for maintaining one-way passage of the gas of the main line from the branch line to the vent line.
6. The hydrogen-doped natural gas pressure regulating system according to claim 5, wherein a first pressure rough regulating device, a first pressure sensing device, a second pressure rough regulating device and a second pressure sensing device are sequentially arranged on the main pipeline along the gas flowing direction in the main pipeline, a first branch pipeline is led out between the first pressure rough regulating device and the first pressure sensing device, a first pressure fine regulating device and a first check valve are sequentially arranged on the first branch pipeline, a second branch pipeline is led out between the second pressure rough regulating device and the second pressure sensing device, and a second pressure fine regulating device and a second check valve are sequentially arranged on the second branch pipeline.
7. A method for regulating the pressure of hydrogen-doped natural gas in a limited space, which is characterized in that the method is realized by adopting the system for regulating the pressure of the hydrogen-doped natural gas according to claim 1, and comprises the following steps: The pressure rough adjusting device is utilized to adjust the pressure of the gas of the main pipeline according to a target preset pressure range; after the pressure coarse adjustment device is adjusted, acquiring a pressure signal of the pressure sensing device, and when the pressure coarse adjustment device is adjusted in place, introducing the pressure-adjusted hydrogen-doped natural gas into an experimental area; when the pressure signal of the pressure sensing device is obtained to be higher than the maximum value of the first preset pressure range, the pressure rough adjusting device is controlled to increase the opening degree so as to adjust the gas pressure of the main pipeline to the target preset pressure range, or when the pressure signal of the pressure sensing device is obtained to be lower than the minimum value of the first preset pressure range, the pressure rough adjusting device is controlled to decrease the opening degree so as to adjust the gas pressure of the main pipeline to the target preset pressure range, or when the pressure signal of the pressure sensing device is obtained to be in the first preset pressure range, the pressure fine adjusting device is controlled to increase or decrease the opening degree according to the positive or negative difference value of the pressure signal and the target preset pressure range so as to adjust and maintain the gas pressure of the main pipeline to be in the target preset pressure range; and when the pressure signal of the pressure sensing device is acquired again and is in the target preset pressure range, introducing the pressure-regulated hydrogen-doped natural gas into the experimental area.
8. A method for regulating the pressure of hydrogen-doped natural gas in a limited space, which is characterized in that the method is realized by adopting the system for regulating the pressure of the hydrogen-doped natural gas according to claim 6, and comprises the following steps: the first pressure rough adjusting device is utilized to carry out pressure adjustment on the gas pressure of the main pipeline according to a target preset pressure range; after the first pressure coarse adjustment device is adjusted, acquiring a pressure signal of the first pressure sensing device, and when the first pressure coarse adjustment device is adjusted in place, introducing the adjusted hydrogen-doped natural gas into an experimental area; When the pressure signal of the first pressure sensing device is obtained to be higher than the maximum value of a first preset pressure range, the first pressure rough adjusting device is controlled to increase the opening degree so as to adjust the gas pressure of the main pipeline to the target preset pressure range, or when the pressure signal of the first pressure sensing device is obtained to be lower than the minimum value of the first preset pressure range, the first pressure rough adjusting device is controlled to decrease the opening degree so as to adjust the gas pressure of the main pipeline to the target preset pressure range, or when the pressure signal of the first pressure sensing device is obtained to be in the first preset pressure range, the first pressure fine adjusting device is controlled to increase or decrease the opening degree according to the positive or negative difference value of the pressure signal and the target preset pressure range so as to adjust and maintain the gas pressure of the main pipeline to the target preset pressure range; After the first pressure fine adjustment device is adjusted, acquiring a pressure signal of the first pressure sensing device when the pressure signal is in a target preset pressure range, acquiring a pressure signal of the second pressure sensing device, and introducing the adjusted hydrogen-doped natural gas into an experiment area when the gas pressure of the main pipeline is stabilized in the target preset pressure range; When the pressure signal of the second pressure sensing device is obtained to be higher than the maximum value of a second preset pressure range, the second pressure rough adjusting device is controlled to increase the opening degree so as to adjust the gas pressure of the main pipeline to the target preset pressure range, or when the pressure signal of the second pressure sensing device is obtained to be lower than the minimum value of the first preset pressure range, the second pressure rough adjusting device is controlled to decrease the opening degree so as to adjust the gas pressure of the main pipeline to the target preset pressure range, or when the pressure signal of the second pressure sensing device is obtained to be in the second preset pressure range, the second pressure fine adjusting device is controlled to increase or decrease the opening degree according to the positive or negative difference value of the pressure signal and the target preset pressure range so as to adjust and maintain the gas pressure of the main pipeline to the target preset pressure range; And when the pressure signal of the second pressure sensing device is acquired again and is in the target preset pressure range, introducing the pressure-regulated hydrogen-doped natural gas into the experimental area.

Description

Hydrogen-doped natural gas pressure regulating system and method in limited space Technical Field The invention relates to the field of gas pressure control, in particular to a system and a method for regulating the pressure of hydrogen-doped natural gas in a limited space. Background At present, along with the continuous promotion of the implementation progress of the dual-carbon target, the related research of hydrogen and hydrogen-doped natural gas is continuously and deeply carried out. The traditional natural gas and the natural gas after hydrogen addition have certain differences in physical parameters, performance requirements on the accommodating materials, leakage diffusion speed, leakage explosion accident results, influence range and the like. The related research searches the change rule through various means such as calculation, simulation and the like, but the experimental simulation and test are the most intuitive and reliable research methods, which are helpful for overcoming the limitations of the model and obtaining more real and accurate data. The end users of town gas mainly comprise town resident users and industrial users, and the town gas is generally conveyed by adopting a low-pressure pipeline. In the urban pipeline maintenance and repair process, the processes such as welding operation with pressure are commonly used, and when the repair operation is carried out, a micro-pressure or normal-pressure gas environment with the relative pressure of 50 Pa-1000 Pa is involved. The natural gas may bring new risks and hidden dangers to the welding operation under pressure after hydrogen addition, including flame height, flame stability, flame temperature and other combustion characteristics, and weld material performance change and other factors, and the problems are subject to further experimental study. Because the relative pressure of 50 Pa-1000 Pa is lower, the configuration pressure of the hydrogen-doped natural gas is generally more than 0.1 MPa. When the pressure of the hydrogen-doped natural gas is reduced from a high pressure level to a low pressure level, the volume of the gas is in negative correlation with the pressure, the volume expansion rate is higher when the pressure is obviously reduced, and the temperature of the gas is also changed. The sum of the temperature and the gas volume changes can lead to the fact that the gas with the pressure regulated still has large pressure fluctuation, and the experimental pressure is unstable. Therefore, the micro-pressure or normal-pressure experiment of the hydrogen-doped natural gas has higher requirements on the pressure regulating and stabilizing capacity of the equipment, so that the technical difficulty of pressure regulation and pressure stabilization maintenance in the transportation process of the hydrogen-doped natural gas is realized. The prior art generally utilizes a long-distance buffer pipeline, a large-volume buffer tank or a method combining the long-distance buffer pipeline and the large-volume buffer tank to play a role in stabilizing pressure after pressure regulation, the system occupies a large area, more welding seams are involved, after natural gas is mixed with hydrogen, hydrogen atoms can be gathered at the welding seams and the like, the problems of hydrogen loss and the like are caused, and new hidden hazards are brought to experiments. In the existing experimental system, pressure stability is usually ensured by introducing a buffer tank or a buffer pipeline, but the buffer tank is a positive pressure container, the problems of medium leakage and the like are likely to occur, and the natural gas has higher leakage risk at the sealed connection part and the welded junction part of the buffer pipeline after hydrogen is added, so that the risk level of the system can be improved in the two modes, and meanwhile, the space requirement and the construction maintenance cost can be improved due to the introduction of the buffer tank or the buffer pipeline. Disclosure of Invention The invention aims to provide a hydrogen-doped natural gas pressure regulating system and method under a limited space, and solves the problems of low space utilization rate, low safety and high cost of the hydrogen-doped natural gas pressure regulating system in the prior art. The above object of the present invention can be achieved by the following technical solutions: the invention provides a hydrogen-doped natural gas pressure regulating system under a limited space, which comprises: The main pipeline is arranged between an air source and an experiment area, at least one level of pressure rough adjusting device and at least one pressure sensing device are sequentially arranged on the main pipeline along the air flow direction in the main pipeline, the pressure rough adjusting device is used for adjusting the pressure of air flowing into the main pipeline to a target preset pressure range, and the pressure sensing device is used for det