A gas displacement and release metering method, device and mobile skid

Abstract

The present application relates to a gas replacement and release metering method, device and mobile skid, wherein the gas replacement and release metering method comprises: obtaining the pressure level system parameters of the gas supply end, and the pipe section length and pipe section diameter of the gas pipeline to be replaced; determining the replacement and release coefficient according to the pressure level system parameters, the pipe section length and the replacement and release model; determining the pipe section volume of the gas pipeline to be replaced according to the pipe section length and the pipe section diameter; and calculating the gas emission according to the replacement and release coefficient and the pipe section volume. Through the present application, the problem of inaccurate gas emission measurement in gas replacement and release is solved, the safety of the gas replacement and release process is improved, and energy is saved.

Description

Technical Field

[0001] The present application relates to the field of gas metering, and in particular to a gas displacement and release metering method, device and mobile skid. Background Art

[0002] With the development of society and the expansion of the scale of gas pipeline network, many problems in gas safety release, as one of the means to ensure the safe operation of the pipeline network, have attracted more and more attention from industry insiders. At the same time, as a gas company, it is urgent to accurately count and strictly control the release volume in the production process, on the one hand, to provide data support for the calculation of supply and sales difference and gradually achieve refined management; on the other hand, it provides support for the calculation of methane emissions.

[0003] Gas venting mainly includes the following two situations: one is active gas venting, including safety venting, maintenance venting at pressure regulating stations, venting with gas connection and cutting operations, ventilation and replacement venting for new projects and new users, etc.; the other is passive gas venting, such as pipeline accident venting and overpressure venting. Among them, maintenance venting and partial safety venting can estimate the venting amount by combining the pressure, temperature, and pipeline conditions before and after the venting with the gas state equation. However, for replacement venting involving gas connection and cutting and new pipelines (i.e. using gas to replace the air or nitrogen in the pipeline), since the venting process involves a mixture of gas and air or gas and inert gas, it is difficult to calculate the accurate gas emission through the formula.

[0004] At present, there is a general lack of monitoring of the release state of gas at home and abroad. The primary purpose is only to ensure the safe operation of the gas network, and there are no corresponding metering facilities for the gas release volume. Most of the gas emissions during the replacement process rely on theoretical calculation formulas, which have not been verified by actual measurements; at the same time, a gas mixing process will occur during the pipeline replacement process (that is, the gas mixes with the air in the pipe). The pressure in the pipe, the gas flow rate, and the pipe diameter during the mixing process will affect the length of the mixing section. Therefore, the gas concentration distribution during the replacement process is relatively complex, and the mixing of air and gas in the pipe changes nonlinearly. The error in estimating the gas emission through theoretical calculation is relatively large. On the one hand, this makes it easy for the gas release volume to exceed the safety standard concentration, which will bring safety hazards; at the same time, the lack of gas release volume monitoring will also cause gas waste, which is not conducive to energy conservation and emission reduction.

[0005] Currently, no effective solution has been proposed for the problem of inaccurate measurement of gas emissions during gas replacement and release. Summary of the invention

[0006] The embodiments of the present application provide a gas displacement and release metering method, device and mobile skid to at least solve the problem of inaccurate gas emission metering during gas displacement and release.

[0007] In a first aspect, an embodiment of the present application provides a gas displacement and release metering method.

[0008] In some embodiments, the gas displacement emission metering method includes:

[0009] Obtain the pressure level parameters of the gas supply end, as well as the length and diameter of the pipe section of the gas pipeline to be replaced;

[0010] Determining a displacement and diffusion coefficient according to the pressure level system parameters, the pipe section length and the displacement and diffusion model;

[0011] Determining the volume of the pipe section of the gas pipeline to be replaced according to the length of the pipe section and the diameter of the pipe section;

[0012] The gas emission amount is calculated according to the displacement diffusion coefficient and the pipe section volume.

[0013] In some of the embodiments, the pressure level parameters are medium-low pressure parameters or sub-high pressure and above parameters.

[0014] In some embodiments, determining the displacement diffusion coefficient according to the pressure level system parameter, the pipe section length and the displacement diffusion model includes: when the pressure level system parameter is a medium and low pressure parameter, determining the displacement diffusion coefficient according to the following steps:

[0015] When the length of the pipe section is less than or equal to 0.7 km, y=1.3;

[0016] When the length of the pipe section is greater than 0.7 km and less than 3.95 km, y=0.09x+1.37;

[0017] When the length of the pipe section is greater than or equal to 3.95 kilometers, y=1;

[0018] Wherein, y is the displacement diffusion coefficient, and x is the value corresponding to the length of the pipe section.

[0019] Wherein, y is the displacement diffusion coefficient, and x is the value corresponding to the length of the pipe section.

[0020] In some embodiments, determining the displacement diffusion coefficient according to the pressure level system parameter, the pipe section length and the displacement diffusion model includes: when the pressure level system parameter is a sub-high pressure parameter or above, determining the displacement diffusion coefficient according to the following steps:

[0021] When the length of the pipe section is less than or equal to 0.7 km, y=0.2x+2.45;

[0022] When the length of the pipe section is greater than 0.7 km and less than 3.95 km, y=0.4x+2.59;

[0023] When the length of the pipe section is greater than or equal to 3.95 kilometers, y=1;

[0024] Wherein, y is the displacement diffusion coefficient, and x is the length of the pipe section.

[0025] In some embodiments, determining the volume of the pipe section of the gas pipeline to be replaced according to the pipe section length and the pipe section diameter includes:

[0026] Determine the volume of the gas pipeline section to be replaced according to the following formula:

[0027] πd 2 x / 4

[0028] Wherein, d is the diameter of the pipe section, and x is the length of the pipe section.

[0029] In some embodiments, the calculating of the gas emission according to the displacement diffusion coefficient and the pipe section volume includes:

[0030] The gas emission amount is the product of the displacement diffusion coefficient and the volume of the pipe section.

[0031] In a second aspect, an embodiment of the present application provides a gas displacement and release metering device.

[0032] In some embodiments, the gas displacement and diffusion metering device includes a displacement data acquisition module, a diffusion coefficient determination module, a pipe section volume determination module and a gas emission calculation module:

[0033] The replacement data acquisition module is used to obtain the pressure level parameters of the gas supply end, and the length and diameter of the pipe section of the gas pipeline to be replaced;

[0034] The dispersion coefficient determination module is used to determine the displacement dispersion coefficient according to the pressure level system parameter, the pipe section length and the displacement dispersion model;

[0035] The pipe section volume determination module is used to determine the pipe section volume of the gas pipeline to be replaced according to the pipe section length and the pipe section diameter;

[0036] The gas emission calculation module is used to calculate the gas emission according to the displacement diffusion coefficient and the pipe section volume.

[0037] In a third aspect, an embodiment of the present application provides a mobile skid for gas displacement and release metering.

[0038] In some embodiments, the gas displacement and release metering mobile skid includes a shut-off valve, a flow meter, a metering path and a bypass path:

[0039] The stop valve is used to control the gas pressure and flow rate during the replacement process according to the pressure level parameters of the gas supply end;

[0040] The flow meter is used to measure the volume of the gas during the displacement process, thereby determining the amount of gas discharged;

[0041] The metering path is used as a passage for the gas to flow when the displacement process is implemented, and / or as a passage for the gas to flow when the pressure increase process is implemented;

[0042] The bypass passage is used to serve as a passage for gas flow when the metering passage fails and / or as a passage for gas flow when a pressure boosting process is being implemented.

[0043] In some of the embodiments, when the pressure level system parameter is a medium-low pressure parameter, the metering path is used as a passage for the gas flow when the replacement process is implemented, and is used as a passage for the gas flow when the pressure boosting process is implemented after the replacement process is completed;

[0044] When the pressure level system parameter is a sub-high pressure parameter or above, the metering path is used as a path for the gas flow when the displacement process is implemented, and the bypass path is used as a path for the gas flow when the pressure boosting process is implemented after the displacement process is completed.

[0045] In some of the embodiments, the gas replacement and release metering mobile skid is connected between the gas pipe section to be replaced and the conventional gas pipe section through a gate well release valve or a hole opening machine interface.

[0046] Compared with the related art, the gas displacement and release metering method, device and mobile skid provided in the embodiments of the present application determine the displacement and release coefficient and the pipe section volume through the pressure level system parameters, pipe section length, pipe section diameter and displacement and release model at the gas supply end, thereby calculating the gas emission. This solves the problem of inaccurate gas emission measurement in gas displacement and release, improves the safety of the gas displacement and release process, and saves energy.

[0047] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0049] Figure 1 It is a hardware structure block diagram of a terminal according to a gas displacement and release metering method according to an embodiment of the present application;

[0050] Figure 2 is a flow chart of a gas displacement and release metering method according to an embodiment of the present application;

[0051] Figure 3 is a structural block diagram of a gas displacement and diffusion metering device according to an embodiment of the present application;

[0052] Figure 4 is a structural block diagram of a gas displacement and release metering mobile skid according to an embodiment of the present application;

[0053] Figure 5 It is a schematic diagram of a displacement and release model determined by a gas displacement and release metering mobile skid according to an embodiment of the present application;

[0054] Figure 6 It is a preferred hardware structure diagram of the gas displacement and release metering mobile skid according to an embodiment of the present application. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application. In addition, it can also be understood that although the efforts made in this development process may be complex and lengthy, for ordinary technicians in the field related to the contents disclosed in the present application, some changes such as design, manufacturing or production based on the technical contents disclosed in the present application are only conventional technical means, and should not be understood as insufficient contents disclosed in the present application.

[0056] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0057] Unless otherwise defined, the technical terms or scientific terms involved in this application should be understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the" and the like involved in this application do not indicate a quantitative limitation, and may represent the singular or plural. The terms "include", "comprise", "have" and any of their variations involved in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "multiple" involved in this application refers to greater than or equal to two. "Or" describes the association relationship of associated objects, indicating that there can be three relationships, for example, "A or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. The terms "first", "second", "third" and the like involved in the present application are merely used to distinguish similar objects and do not represent a specific ordering of the objects.

[0058] The method embodiment provided in this embodiment can be executed in a terminal, a computer or a similar computing device. Taking running on a terminal as an example, Figure 1 FIG. 1 is a hardware structure block diagram of a terminal of a gas displacement and emission metering method according to an embodiment of the present invention. Figure 1 As shown, the terminal may include one or more ( Figure 1 Only one is shown in the figure) a processor 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA) and a memory 104 for storing data. Optionally, the terminal may also include a transmission device 106 and an input / output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is for illustration only and does not limit the structure of the above terminal. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations shown.

[0059] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the gas displacement and release metering method in the embodiment of the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, to implement the above method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories may be connected to the terminal via a network. Examples of the above network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0060] The transmission device 106 is used to receive or send data via a network. The specific example of the above network may include a wireless network provided by a communication provider of the terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (Radio Frequency, referred to as RF) module, which is used to communicate with the Internet wirelessly.

[0061] This embodiment provides a gas displacement and release metering method. Figure 2 is a flow chart of a gas displacement and release metering method according to an embodiment of the present application, such as Figure 2 As shown, the process includes the following steps:

[0062] Step S201, obtaining the pressure level parameters of the gas supply end, and the length and diameter of the pipe section of the gas pipeline to be replaced.

[0063] The gas emission of the gas replacement project is mainly affected by the mixing section, which is affected by the diameter, length and replacement speed of the pipeline to be replaced. The replacement speed is closely related to the pressure level system at the gas supply end, so it is also necessary to obtain the pressure level system parameters at the gas supply end.

[0064] Step S202, determining a displacement diffusion coefficient according to the pressure level system parameters, the pipe section length and the displacement diffusion model.

[0065] After obtaining the pressure level parameters and pipe section length, the gas displacement and release metering mobile skid is used to complete the metering and calculation of multiple displacement operations, and the displacement and release model is obtained. Based on the displacement and release model, the displacement and release coefficient is determined.

[0066] Step S203: determining the volume of the pipe section of the gas pipeline to be replaced according to the length of the pipe section and the diameter of the pipe section.

[0067] After obtaining the length and diameter of the pipe section, the pipe section volume of the gas pipeline to be replaced can be obtained by calculation. It is worth mentioning that in a single measurement, the mobile skid for gas replacement and metering can be used for on-site replacement project data collection. Stop metering immediately after the replacement is qualified, and count the data. At this time, the gas discharge of the replacement project can be obtained by subtracting the pipe storage gas volume from the accumulated gas volume of the flow meter. Considering that the pressure in the pipe is approximately normal pressure after the replacement is qualified, the pipe storage gas volume is approximately equal to the pipe volume.

[0068] Step S204: Calculate the gas emission according to the displacement diffusion coefficient and the pipe section volume.

[0069] According to the displacement diffusion coefficient and the pipe section volume obtained in the above steps, the gas emission volume can be obtained by calculating the product of the displacement diffusion coefficient and the pipe section volume.

[0070] Through the above steps, the embodiment of the present application determines the displacement diffusion coefficient according to the pressure level system parameters, the pipe section length and the displacement diffusion model, determines the pipe section volume of the gas pipeline to be replaced according to the pipe section length and the pipe section diameter, and further obtains the gas emission according to the displacement diffusion coefficient and the pipe section volume, thereby solving the problem of inaccurate gas emission measurement in gas displacement and diffusion, improving the safety of the gas displacement and diffusion process, and saving energy.

[0071] In some of the embodiments, the pressure level parameters are medium-low pressure parameters or sub-high pressure and above parameters.

[0072] In the embodiment of the present application, the larger the pressure level of the gas supply end, the higher the replacement speed, and the longer the length of the gas mixing section. Therefore, under the same conditions, the gas discharge of the pipe section to be replaced must be greater than the medium and low pressure if the gas supply end is sub-high pressure or above, that is, the ratio of the gas discharge of sub-high pressure or above to the pipe volume is greater than the medium and low pressure gas discharge to the pipe volume. Therefore, it is necessary to determine the range corresponding to the pressure level parameter of the gas supply end. Usually, the medium and low pressure parameter is 0-0.4MPa, and the sub-high pressure or above parameter is 0.4-4MPa.

[0073] In some embodiments, step S202 includes:

[0074] Step S2021, when the pressure level system parameter is a medium and low pressure parameter, determine the displacement dispersion coefficient according to the following steps:

[0075] When the length of the pipe section is less than or equal to 0.7 km, y=1.3;

[0076] When the length of the pipe section is greater than 0.7 km and less than 3.95 km, y=0.09x+1.37;

[0077] When the length of the pipe section is greater than or equal to 3.95 kilometers, y=1;

[0078] Wherein, y is the displacement diffusion coefficient, and x is the value corresponding to the length of the pipe section.

[0079] When the pressure level system parameters are medium and low pressure parameters, the corresponding displacement diffusion coefficient is determined based on the obtained pipe section length according to the method corresponding to the displacement diffusion model.

[0080] In some embodiments, step S202 includes:

[0081] Step S2022, when the pressure level system parameter is a sub-high pressure parameter or above, determine the displacement dispersion coefficient according to the following steps:

[0082] When the length of the pipe section is less than or equal to 0.7 km, y=0.2x+2.45;

[0083] When the length of the pipe section is greater than 0.7 km and less than 3.95 km, y=0.4x+2.59;

[0084] When the length of the pipe section is greater than or equal to 3.95 kilometers, y=1;

[0085] Wherein, y is the displacement diffusion coefficient, and x is the length of the pipe section.

[0086] When the pressure level system parameter is a sub-high pressure parameter, the corresponding displacement diffusion coefficient is determined based on the obtained pipe section length according to the method corresponding to the displacement diffusion model.

[0087] In some embodiments, step S203 includes:

[0088] Step S2031, determine the volume of the section of the gas pipeline to be replaced according to the following formula:

[0089] πd 2 x / 4

[0090] Wherein, d is the diameter of the pipe section, and x is the length of the pipe section.

[0091] In some embodiments, step S204 includes:

[0092] Step S2041: The gas emission is the product of the displacement diffusion coefficient and the volume of the pipe section.

[0093] It should be noted that the steps shown in the above process or the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0094] This embodiment also provides a gas displacement and release metering device, which is used to implement the above embodiments and preferred implementations, and will not be repeated here. As used below, the terms "module", "unit", "subunit", etc. can be a combination of software or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0095] Figure 3 is a structural block diagram of a gas displacement and diffusion metering device according to an embodiment of the present application, such as Figure 3 As shown, the device includes: a replacement data acquisition module 10, a dispersion coefficient determination module 20, a pipe section volume determination module 30 and a gas emission calculation module 40:

[0096] The replacement data acquisition module 10 is used to obtain the pressure level parameters of the gas supply end, and the length and diameter of the pipe section of the gas pipeline to be replaced;

[0097] The dispersion coefficient determination module 20 is used to determine the displacement dispersion coefficient according to the pressure level system parameter, the pipe section length and the displacement dispersion model;

[0098] The pipe section volume determination module 30 is used to determine the pipe section volume of the gas pipeline to be replaced according to the pipe section length and the pipe section diameter;

[0099] The gas emission calculation module 40 is used to calculate the gas emission according to the displacement diffusion coefficient and the pipe section volume.

[0100] It should be noted that the above modules can be functional modules or program modules, and can be implemented by software or hardware. For modules implemented by hardware, the above modules can be located in the same processor; or the above modules can be located in different processors in any combination.

[0101] Optionally, in this embodiment, the processor may be configured to perform the following steps through a computer program:

[0102] Obtain the pressure level parameters of the gas supply end, as well as the length and diameter of the pipe section of the gas pipeline to be replaced;

[0103] Determining a displacement and diffusion coefficient according to the pressure level system parameters, the pipe section length and the displacement and diffusion model;

[0104] Determining the volume of the pipe section of the gas pipeline to be replaced according to the length of the pipe section and the diameter of the pipe section;

[0105] The gas emission amount is calculated according to the displacement diffusion coefficient and the pipe section volume.

[0106] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementation modes, and this embodiment will not be described in detail here.

[0107] The present application also provides a gas displacement and release metering mobile skid for determining a displacement and release model. Figure 4 As shown, in some embodiments, the gas displacement and release metering mobile skid includes a stop valve 100, a flow meter 200, a metering path 300 and a bypass path 400:

[0108] The stop valve 100 is used to control the gas pressure and flow rate during the replacement process according to the pressure level parameters of the gas supply end;

[0109] The flow meter 200 is used to measure the volume of the gas during the displacement process, thereby determining the amount of gas discharged;

[0110] The metering path 300 is used as a path for gas flow metering when performing the replacement process, and / or as a path for gas flow when performing the pressure boosting process;

[0111] The bypass passage 400 is used as a passage for the gas to flow when the metering passage fails and / or as a passage for the gas to flow when a pressure boosting process is being implemented.

[0112] In some embodiments, when the pressure level system parameter is a medium-low pressure parameter, the metering path 300 is used as a passage for the gas flow when the replacement process is implemented, and is used as a passage for the gas flow when the pressure boosting process is implemented after the replacement process is completed;

[0113] During the medium-low pressure (0-0.4MPa) replacement, close the bypass passage 400, open the metering passage 300, control the flow pressure through the left ball valve of the metering passage 300, complete the replacement, read the replacement gas volume data; continue to increase the pressure to complete the operation. Compared with the second high pressure and above, the medium-low pressure is not limited by the pressure sensor. After the replacement is qualified and the gas volume value of the flow meter is read, the pressure can be continued to be increased through the metering passage 300.

[0114] In some of the embodiments, when the pressure level system parameter is a sub-high pressure parameter or above, the metering path 300 is used as a path for the gas flow when the displacement process is implemented, and the bypass path 400 is used as a path for the gas flow when the pressure boosting process is implemented after the displacement process is completed.

[0115] When replacing at a sub-high pressure or above (0.4-4MPa), close the bypass passage 400, open the metering passage 300, control the flow pressure through the ball valve on the left side of the metering passage 300, complete the replacement, and read the replacement gas volume data; close the metering passage 300, open the bypass passage 400, and complete the pressure increase process. Since the pressure sensor in the flow meter 200 is suitable for medium and low pressures, after the replacement at a sub-high pressure or above is qualified, it is necessary to close the metering passage 300 and use the bypass passage 400 to complete the pressure increase.

[0116] In some of the embodiments, the gas replacement and release metering mobile skid is connected between the gas pipe section to be replaced and the conventional gas pipe section through a gate well release valve or a hole opening machine interface.

[0117] During the replacement process, the end release involves a mixture of gas and air, and the actual gas release volume cannot be obtained. Therefore, for the calculation of the gas release volume of the replacement project, the gas replacement release metering mobile skid needs to be installed at the gas injection port. The gas release volume of the replacement project is calculated by subtracting the pipe inventory from the gas volume used for qualified replacement. Therefore, the use of the gas replacement release metering mobile skid is limited to replacement projects that use jumper pipelines as the gas source, such as the gate well release valve jumper and the hole opening machine interface jumper.

[0118] The embodiment of the present application also provides a displacement and release model determined by a gas displacement and release metering mobile skid. Figure 5 This is a schematic diagram of a displacement and release model determined by the gas displacement and release metering mobile skid in the embodiment of the present application. Figure 5As shown in the figure, the pipe length x is the length of the pipe section, and the conversion coefficient y is the displacement dispersion coefficient. In a single measurement, the mobile skid for gas displacement dispersion metering is used to collect data for on-site gas replacement projects. Stop metering immediately after the replacement is qualified, and collect statistical data. Since it is necessary to calculate the gas emissions of the replacement project, it is necessary to use the accumulated gas volume of the flow meter minus the gas volume in the pipe. Considering that the pressure in the pipe is approximately normal pressure after the replacement is qualified, the gas volume in the pipe is approximately equal to the pipe volume. The gas emissions of the replacement project are mainly affected by the mixing section, which is affected by the diameter, length and replacement speed of the pipeline to be replaced. For the pipe diameter, since the gas pipe diameter in the urban gas replacement project is not much different, this influencing factor is ignored. For the replacement speed, it is closely related to the pressure level system at the gas supply end, because the pressure level system affects the flow rate, thereby affecting the replacement speed. Therefore, the length of the pipe section to be replaced and the pressure level system at the gas supply end will be two key factors in the calculation of gas emissions. The mixing length reflects the size of the displacement dispersion coefficient to a certain extent, that is, the longer the mixing length, the greater the displacement dispersion coefficient.

[0119] By using the gas displacement and release metering mobile skid to complete the metering and accounting of multiple displacement operations, the following results are obtained: Figure 5 The displacement and release model shown. Among them, the schematic line above the figure represents the replacement project of sub-high pressure and above, and the schematic line below represents the medium and low pressure replacement project. The larger the pressure level at the gas supply end, the higher the replacement speed will be, and the length of the mixing section will increase. Therefore, under the same conditions, the gas emission of the pipe section to be replaced, if the gas supply end is sub-high pressure and above, must be greater than the medium and low pressure, that is, the ratio of sub-high pressure and above gas emission / pipe volume is greater than the medium and low pressure, which is why the upper schematic line is always higher than the lower schematic line; secondly, the longer the length of the pipe section to be replaced, the longer the length of the mixing section, but the growth rate of the length of the mixing section is getting lower and lower and tends to be stable, so the proportion of the mixing section in the entire pipe section to be replaced decreases with the increase of the replacement length, that is, the longer the pipe section to be replaced, the smaller the ratio of gas emission / pipe volume, so Figure 5 As the x value increases, the y value decreases.

[0120] like Figure 6 As shown, the embodiment of the present application also provides a preferred hardware structure diagram of a gas replacement and release metering mobile skid. Among them, the ball valve and the butterfly valve are used as stop valves, and the flow meter is preferably an ultrasonic flow meter that does not require front and rear straight pipe sections and has no obstructions. The scope of application of the metering mobile skid is as follows. Applicable pressure level system: replacement projects of 4MPa and below; flange specifications and pipe diameters to be connected: steel interface, national standard flange, connecting pipe diameter DN50 / DN80 / DN100 / DN150 / DN200 (if there are other pipe diameters, they can be connected through reducers); installation location: between the conventional gas source pipeline and the pipeline to be replaced, such as the gate well release valve; flow meter flow range: working conditions 4.0~650m 3 / h; Length of pipe to be replaced: no requirement.

[0121] Taking the case where the pressure level system parameters are sub-high pressure and above as an example, the preferred gas release and replacement process of the embodiment of the present application is as follows: the release port of the normal gas pipe section is connected to the left side of the metering mobile skid through an appropriate reducer and a metal hose. The right side of the metering mobile skid is also connected to the release port of the pipe section to be replaced through a reducer and a metal hose. Close the ball valve and butterfly valve of the bypass passage. Two valves are set here to avoid internal leakage of a single valve and thus affect the metering accuracy. Open the ball valve on the right side of the metering path, slowly open the ball valve on the left side of the metering path, check the pressure gauge of the metering path and control the pressure within a reasonable range. Start the replacement. When the gas concentration measurement value of the sampled gas at the end to be replaced is greater than 90% for three consecutive times, the replacement is qualified. At this time, read the gas volume value of the flow meter for subsequent calculation of the gas emission.

[0122] Since the pressure sensor in the flow meter is suitable for medium and low pressure, after the replacement of the sub-high pressure and above is qualified, it is necessary to close the metering line and use the bypass line to complete the pressure increase. At this time, close the two ball valves on the left and right sides of the metering line, open the ball valve and butterfly valve of the bypass line to complete the pressure increase. After the pressure increase is completed, remove the metal hoses at both ends, open the vent valve at the upper end of the metering line, and vent the gas in the metering skid.

[0123] Taking the case where the pressure level system parameter is a medium and low pressure parameter as an example, the preferred gas release replacement process of the embodiment of the present application is as follows: close the bypass path and open the metering path, control the flow pressure through the left ball valve of the metering path, complete the replacement, read the replacement gas volume data; continue to increase the pressure to complete the operation. Compared with the second high pressure and above, the medium and low pressure is not limited by the pressure sensor. After the replacement is qualified and the gas volume value of the flow meter is read, the pressure can continue to be increased through the metering path.

[0124] Those skilled in the art should understand that the technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A gas displacement and emission metering method, characterized in that: include: Obtain the pressure level parameters of the gas supply end, as well as the length and diameter of the pipe section of the gas pipeline to be replaced; Determining a displacement and diffusion coefficient according to the pressure level system parameters, the pipe section length and the displacement and diffusion model; Determining the volume of the pipe section of the gas pipeline to be replaced according to the length of the pipe section and the diameter of the pipe section; Calculating the gas emission according to the displacement diffusion coefficient and the pipe section volume; Wherein: the pressure level system parameters are medium and low pressure parameters or sub-high pressure and above parameters; Determining the displacement diffusion coefficient according to the pressure level system parameter, the pipe section length and the displacement diffusion model includes: when the pressure level system parameter is a medium and low pressure parameter, determining the displacement diffusion coefficient according to the following steps: When the length of the pipe section is less than or equal to 0.7 km, y=1.3; When the length of the pipe section is greater than 0.7 km and less than 3.95 km, y=0.09x+1.37; When the length of the pipe section is greater than or equal to 3.95 kilometers, y=1; Wherein, y is the displacement diffusion coefficient, and x is the value corresponding to the length of the pipe section; Determining the displacement diffusion coefficient according to the pressure level system parameter, the pipe section length and the displacement diffusion model includes: when the pressure level system parameter is a sub-high pressure parameter or above, determining the displacement diffusion coefficient according to the following steps: When the length of the pipe section is less than or equal to 0.7 km, y=0.2x+2.45; When the length of the pipe section is greater than 0.7 km and less than 3.95 km, y=0.4x+2.59; When the length of the pipe section is greater than or equal to 3.95 kilometers, y=1; Wherein, y is the displacement diffusion coefficient, and x is the length of the pipe section.

2. The gas displacement and emission metering method according to claim 1, characterized in that: Determining the pipe section volume of the gas pipeline to be replaced according to the pipe section length and the pipe section diameter includes: Determine the volume of the gas pipeline section to be replaced according to the following formula: pd 2 x / 4 Wherein, d is the diameter of the pipe section, and x is the length of the pipe section.

3. The gas displacement and release metering method according to claim 1, characterized in that: The gas emission amount is calculated according to the displacement diffusion coefficient and the pipe section volume, comprising: The gas emission amount is the product of the displacement diffusion coefficient and the volume of the pipe section.

4. A gas displacement and diffusion metering device, characterized in that: It includes displacement data acquisition module, dispersion coefficient determination module, pipe section volume determination module and gas emission calculation module: The replacement data acquisition module is used to obtain the pressure level parameters of the gas supply end, and the length and diameter of the pipe section of the gas pipeline to be replaced; The dispersion coefficient determination module is used to determine the displacement dispersion coefficient according to the pressure level system parameter, the pipe section length and the displacement dispersion model; The pipe section volume determination module is used to determine the pipe section volume of the gas pipeline to be replaced according to the pipe section length and the pipe section diameter; The gas emission calculation module is used to calculate the gas emission according to the displacement diffusion coefficient and the pipe section volume; Wherein: the pressure level system parameters are medium and low pressure parameters or sub-high pressure and above parameters; Determining the displacement diffusion coefficient according to the pressure level system parameter, the pipe section length and the displacement diffusion model includes: when the pressure level system parameter is a medium and low pressure parameter, determining the displacement diffusion coefficient according to the following steps: When the length of the pipe section is less than or equal to 0.7 km, y=1.3; When the length of the pipe section is greater than 0.7 km and less than 3.95 km, y=0.09x+1.37; When the length of the pipe section is greater than or equal to 3.95 kilometers, y=1; Wherein, y is the displacement diffusion coefficient, and x is the value corresponding to the length of the pipe section; Determining the displacement diffusion coefficient according to the pressure level system parameter, the pipe section length and the displacement diffusion model includes: when the pressure level system parameter is a sub-high pressure parameter or above, determining the displacement diffusion coefficient according to the following steps: When the length of the pipe section is less than or equal to 0.7 km, y=0.2x+2.45; When the length of the pipe section is greater than 0.7 km and less than 3.95 km, y=0.4x+2.59; When the length of the pipe section is greater than or equal to 3.95 kilometers, y=1; Wherein, y is the displacement diffusion coefficient, and x is the length of the pipe section.

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