CN210036908U - High-pressure natural gas flow primary standard device with adjustable sonic nozzle - Google Patents
High-pressure natural gas flow primary standard device with adjustable sonic nozzle Download PDFInfo
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- CN210036908U CN210036908U CN201921128671.0U CN201921128671U CN210036908U CN 210036908 U CN210036908 U CN 210036908U CN 201921128671 U CN201921128671 U CN 201921128671U CN 210036908 U CN210036908 U CN 210036908U
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Abstract
The utility model relates to a metrology field discloses a high-pressure natural gas flow primary standard device of correctable sonic nozzle, in this device, utilizes online gas chromatograph to detect the gaseous initial component of the primary standard device inlet end of HPPP, and passes through the actual volume flow q through the sonic nozzle of HPPP primary standard device measurementv(ii) a The sound velocity measuring device is used for measuring the sound velocity in the air inlet pipeline of the sound velocity nozzle; the verification control system is used for correcting the gas molar mass calculated by the gas initial component according to the sound velocity and calculating the sound velocity nozzle by using the corrected gas molar massCoefficient of flow Cd. The utility model provides a problem of the unable direct calibration sonic nozzle of HPPP primary standard device, through revising the outflow coefficient C of sonic nozzledTherefore, the conversion error is small when the volume flow passing through the sonic nozzle is converted into the mass flow, and the measurement accuracy is high.
Description
Technical Field
The utility model relates to a metrological field, concretely relates to high pressure natural gas flow primary standard device of correctable sonic nozzle.
Background
The gas flow is required to be measured in various fields such as engine thrust performance testing, natural gas flowmeter verification/calibration and the like, and the measurement accuracy of the gas flow depends on the measurement accuracy of a gas flow standard device.
The primary standard device for gas flow mainly comprises a mass method and a volume method. The mt method standard device is mainly based on a mass method, is also called as a mass-time method standard device, and has the main principle that gas is introduced into a container with constant weight, the mass flow of the gas is solved according to the mass and the introduction time of the introduced gas, and the mt method standard device can directly transmit the quantity value to a sonic nozzle of a mass flowmeter belonging to the same genus. The original-level standard device of the mt method has high working pressure and large flow, the maximum working pressure of the original-level standard device of the mt method in China is 8MPa, the maximum flow is 8kg/s, and the expansion uncertainty of the device is 0.1% (k is 2). The volumetric method comprises a pVTt method standard device, an HPPP standard device and the like, the piston type HPPP primary standard device is greatly influenced by the machining level of a high-pressure volume pipe, the maximum working pressure of the current domestic HPPP primary standard device is 10MPa, and the maximum flow is 480m3The expansion uncertainty of the device is 0.07% (k 2). The Venturi nozzle is a measuring pipe for measuring gas flow, and comprises a contraction section, a throat part and a diffusion section, the aperture of the nozzle is gradually reduced from an inlet to the throat part and gradually expanded to an outlet after passing through the throat part, the part with the minimum aperture of the Venturi nozzle is the throat part, a flow passage with the gradually expanded aperture is arranged at the lower part of the throat part, and when the air flow passes through the Venturi nozzle, when the air flow is at subsonic speed, the gas flow velocity of the throat part is along with the pressure difference between the upper part and the lower part (namely the inlet pressure P of the Venturi nozzle)0Outlet pressure P of venturi nozzle1The difference) increases and increases; when the pressure difference between the upstream and downstream reaches a certain value, the gas flow rate at the throat of the Venturi nozzle reaches the maximum flow rate, namely the local sound velocity, the gas flow rate through the Venturi nozzle reaches the maximum, namely the critical flow, and if P is increased, the gas flow rate reaches the critical flow rate0The gas flow rate at the throat will remain constant, i.e. no longer subject to the downstream outlet pressure P1The venturi nozzle is a critical flow venturi nozzle, also called sonic nozzle, and the inlet pressure P of the sonic nozzle0Called stagnation pressure, and the inlet temperature of the sonic nozzle called stagnation temperature T0，P1And P0Is referred to as the critical pressure ratio. The sonic nozzle has the characteristics of simple structure, no movable part, high accuracy, good repeatability and the like, and is generally used as a transmission standard at home and abroad for transmitting the measurement value of other types of gas flow meters.
According to the requirements of JJG620 'Critical flow Venturi nozzle verification regulation', the sonic nozzle is verified once every 5 years, in the field of high-pressure natural gas metering, only an mt method natural gas flow primary standard device can directly calibrate the sonic nozzle at present, and because natural gas has the characteristics of compressibility, complex components and the like, an online gas chromatograph is far away from the actual installation position of the sonic nozzle, under the condition of low flow rate circulation of the natural gas, the molar mass of the natural gas detected by the online gas chromatograph is greatly different from the actual molar mass at the sonic nozzle, and in practical application, the online gas chromatograph is very difficult to correct the molar mass of the gas, so that the uncertainty of the actual molar mass of the natural gas at the sonic nozzle is large, the calculation uncertainty of the outflow coefficient of the sonic nozzle is large, and the conversion error is large when the volume flow passing through the sonic nozzle is converted into the mass flow, this is also the main reason why the mt method standard device and the HPPP method standard device cannot be directly compared.
SUMMERY OF THE UTILITY MODEL
In order to overcome among the prior art the volume flow conversion through the sonic nozzle and for mass flow the time conversion error big, lead to the problem of the unable direct calibration sonic nozzle of HPPP primary standard device, the utility model provides a but high pressure natural gas flow primary standard device of calibration sonic nozzle.
The device comprises a verification control system, an HPPP primary standard device 2 arranged at the upstream of a sonic nozzle 4, an online gas chromatograph 1 arranged at the gas inlet end of the HPPP primary standard device 2, a sonic velocity measuring device 3 arranged between the HPPP primary standard device 2 and the sonic nozzle 4, and matched pipelines and valves;
wherein, the online gas chromatograph 1 is used for detecting the gas initial components at the gas inlet end of the HPPP primary standard device 2;
the HPPP primary standard device 2 is used for measuring the actual volume flow q passing through the sonic nozzle 4v；
The sound velocity measuring device 3 is used for measuring the sound velocity in the air inlet pipeline of the sonic nozzle 4;
the verification control system is used for correcting the gas molar mass calculated from the initial gas components according to the sound velocity, and calculating the outflow coefficient C of the sonic nozzle 4 by using the corrected gas molar massd。
Preferably, the HPPP primary standard device 2 comprises a high pressure volume tube 5, a piston 6, a position sensor 7 and a timer;
the piston 6 reciprocates at a constant speed in the volume measuring section of the high-pressure volume pipe 5 in a free replacement or forced replacement mode;
the position sensor 7 and the timer are used for recording the position variation of the piston 6 and the corresponding moving time respectively.
Preferably, the high-pressure natural gas flow primary standard device further comprises:
the temperature sensor 8 and the temperature transmitter 9 are arranged at the air inlet end of the sonic nozzle 4, and the temperature transmitter 9 is used for receiving a temperature signal measured by the temperature sensor 8;
Preferably, temperature transmitter 9, adiabatic transformation 11 and differential pressure transmitter 12 respectively with verify the control system and be connected, will the temperature/pressure signal of sonic nozzle 4 inlet end carries after converting into standard electrical signal verify the control system.
Preferably, the standard electrical signal is a current signal and/or a voltage signal.
Preferably, the sound speed measurement device 3 is an ultrasonic flow meter.
According to the technical scheme, the sound velocity measuring device is used for measuring the sound velocity in the air inlet pipeline of the sonic nozzle, the gas molar mass calculated from the initial gas components is corrected according to the sound velocity to obtain the actual gas molar mass at the upstream inlet of the sonic nozzle, and the actual gas molar mass is used for calculating the outflow coefficient C of the sonic nozzledThe uncertainty is small, so that the conversion error is small when the volume flow measured by the HPPP primary standard device is converted into the mass flow, comparison among primary standard devices of different principles is facilitated, and the metering accuracy of the sonic nozzle is improved.
Drawings
FIG. 1 is a schematic process flow diagram of a high pressure natural gas flow primary standard plant.
Description of the reference numerals
An on-line gas chromatograph 1; HPPP primary standard device 2; a sound velocity measurement device 3; a sonic nozzle 4; a high pressure volumetric tube 5; a piston 6; a position sensor 7; a temperature sensor 8; a temperature transmitter 9; a pressure sensor 10; an absolute pressure transmitter 11; differential pressure transmitter 12.
Detailed Description
The following detailed description of the embodiments of the present invention will be made with reference to the accompanying drawings. It is to be understood that the description of the embodiments herein is for purposes of illustration and explanation only and is not intended to limit the invention.
The natural gas has the characteristics of compressibility, complex components and the like, in the process of calibrating the sonic nozzle, the molar mass of the natural gas is mainly obtained by analyzing and calculating the components of an online gas chromatograph of a station, the online gas chromatograph is very difficult to correct in practical application, the online gas chromatograph is far away from the actual installation position of the nozzle, the molar mass of the gas at the online gas chromatograph and the actual numerical value at the nozzle have larger difference under the condition of lower flow rate, when the HPPP primary standard device calibrates the sonic nozzle, the conversion error between the volume flow and the mass flow passing through the sonic nozzle is larger, and the requirement of high-accuracy measurement transmission cannot be met, so the measurement uncertainty when the HPPP primary standard device calibrates the sonic nozzle is larger.
As shown in fig. 1, the present invention provides a high pressure natural gas flow primary standard device capable of calibrating sonic nozzle, which comprises a verification control system (not shown), an HPPP primary standard device 2 arranged at the upstream of the sonic nozzle 4, a gas chromatograph 1 arranged at the gas inlet end of the HPPP primary standard device 2, a sound velocity measuring device 3 arranged between the HPPP primary standard device 2 and the sonic nozzle 4, and matched pipelines and valves.
Wherein the gas chromatograph 1 is used for detecting the initial components of the gas entering the HPPP primary standard device 2.
The HPPP primary standard device 2 is used for measuring the actual volume flow q passing through the sonic nozzle 4v。
The sound velocity measuring device 3 is used for measuring the sound velocity in the air inlet pipeline of the sonic nozzle 4.
From the initial composition of the gas, gas physical parameters including a critical flow function C, a gas molar mass M, and a gas compression factor Z can be calculated. The verification control system is used for correcting the gas molar mass M according to the measured sound velocity and calculating the outflow coefficient C of the sonic nozzle 4 by using the corrected gas molar mass Md。
According to a preferred embodiment of the present invention, the HPPP master scale device 2 comprises a high pressure volume tube 5, a piston 6, a position sensor 7 and a timer, as well as a plurality of valves for controlling the gas flow rate.
The high-pressure volume pipe 5 has a constant measuring section length and a constant diameter, and the piston 6 reciprocates at a constant speed in the volume measuring section of the high-pressure volume pipe 5 in a free replacement or forced replacement mode. The position sensor 7 and the timer are used for recording the position variation of the piston 6 and the corresponding moving time respectively.
In the present embodiment, the HPPP primary standard device is used to measure the volume flow of the natural gas passing through the sonic nozzle 4, and the measurement flow is as follows:
firstly, closing a side air inlet valve of a high-pressure volume pipe 5, opening a bottom air inlet valve, allowing natural gas to enter the high-pressure volume pipe 5 through the bottom air inlet valve after pressure and flow regulation, closing the bottom air inlet valve and opening the side valve after the temperature reaches a stability requirement, driving a piston 6 to advance at a constant speed by a motor under the control action of a control system, simultaneously recording the position variation of the piston 6 moving from a first control point to a second control point of a measurement section through a position sensor 7, converting the position variation into an effective verification volume delta V, and recording the moving time delta t of the piston 6 from the first control point to the second control point through a timer;
the actual volume flow q through the sonic nozzle 4 is calculated according to equation (1)v；
According to the utility model discloses a preferred embodiment, high-pressure natural gas flow primary standard device still includes:
a temperature sensor 8 and a temperature transmitter 9 arranged at the air inlet end of the sonic nozzle 4, wherein the temperature sensor 8 is used for measuring the temperature of the air inlet end of the sonic nozzle 4, such as stagnation temperature T0And transmits a temperature signal to the temperature transmitter 9.
A pressure sensor 10 and an absolute pressure transmitter 11 arranged at the air outlet end of the high-pressure volume pipe 5, and at least one differential pressure transmission arranged between the high-pressure volume pipe 5 and the sonic nozzle 4Device 12, said absolute pressure transmitter 11 and said at least one differential pressure transmitter 12 being used to measure in cooperation the pressure at the inlet end of said sonic nozzle 4, such as stagnation pressure P0。
Specifically, the pressure sensor 10 is used for measuring the absolute pressure at the air outlet end of the high-pressure volume pipe 5 and transmitting an absolute pressure signal to the absolute pressure transmitter 11; the at least one differential pressure transmitter 12 is used to measure the differential pressure signal between the high pressure volume pipe 5 and the sonic nozzle 4 at different measurement segments. In practical application, the pressure at the air inlet end of the sonic nozzle 4 is calculated by the sum of the absolute pressure and the at least one differential pressure, and the measuring method reduces the measuring error of the pressure.
And, temperature transmitter 9, absolute pressure transmitter 11 and differential pressure transmitter 12 are respectively electrically connected with the verification control system, and convert the temperature/pressure signal of the air inlet end of sonic nozzle 4 into a standard electrical signal and transmit the standard electrical signal to the verification control system.
Preferably, the standard electrical signal is a current signal and/or a voltage signal.
According to a preferred embodiment of the present invention, the sound velocity measuring device 3 is an ultrasonic flowmeter.
Because the propagation velocity of ultrasonic changes along with the change of gas velocity of flow, the embodiment of the utility model provides an install ultrasonic flowmeter in the admission line of sonic nozzle 4 for measure the sound velocity in this admission line. According to AGA Report No.10 published by AGA of American gas Association, the propagation of sound waves in natural gas is characterized by a specific speed, and the theoretical sound velocity is a function related to the pressure, temperature and composition of the natural gas, because the on-line gas chromatograph 1 has measured the composition of the natural gas, the temperature transmitter 9, the absolute pressure transmitter 11 and the differential pressure transmitter 12 respectively measure the temperature and the pressure of the natural gas, and the sound velocity in the natural gas can be theoretically calculated according to a high-precision calculation program and a related state equation provided by the Report to obtain the theoretical sound velocity value. In the present embodiment, the ratio of the theoretical sound velocity value to the measured sound velocity value is calculated, the square of the ratio is used as the correction coefficient of the gas molar mass M, and the corrected gas molar mass M is the corrected gas molar mass MCalculating the outflow coefficient C of the sonic nozzle 4 for the real molar mass of the gas at the inlet of the sonic nozzle using the corrected molar mass of the gasdThe uncertainty can be greatly reduced.
In the utility model, the outflow coefficient CdThe calculation method of (2) is as follows:
respectively measuring stagnation pressure P at the inlet end of the sonic nozzle 40And stagnation temperature T0Wherein the stagnation pressure P0Refers to the pressure, stagnation temperature T, of the gas at rest in the isentropic process0Refers to the temperature of the gas at rest in the isentropic process;
calculating the discharge coefficient C of the sonic nozzle 4 according to the formula (2)d；
Wherein d is the throat diameter of the sonic nozzle 4;
R0is the universal gas constant;
the gas physical parameters calculated from the initial composition of the gas include the critical flow function C, the gas molar mass M, and the gas compression factor Z.
According to the utility model provides a gaseous molar mass M is revised to high pressure natural gas primary standard device accessible, makes the outflow coefficient C of sonic nozzledThe calculation uncertainty is small, the conversion error of the volume flow and the mass flow passing through the sonic nozzle is small, comparison among primary standard devices with different principles is facilitated, and the metering accuracy of the sonic nozzle is improved.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. In the technical idea scope of the present invention, it can be right to the technical solution of the present invention perform multiple simple modifications, including each technical feature combined in any other suitable manner, these simple modifications and combinations should be regarded as the disclosed content of the present invention, and all belong to the protection scope of the present invention.
Claims (6)
1. A sonic nozzle calibratable high pressure natural gas flow primary standard device, comprising a certification control system, an HPPP primary standard device (2) disposed upstream of a sonic nozzle (4), an in-line gas chromatograph (1) disposed at an inlet end of the HPPP primary standard device (2), a sound velocity measurement device (3) disposed between the HPPP primary standard device (2) and the sonic nozzle (4), and associated piping and valves;
wherein the online gas chromatograph (1) is used for detecting the gas initial components at the gas inlet end of the HPPP primary standard device (2);
the HPPP primary standard device (2) is used for measuring the actual volume flow q passing through the sonic nozzle (4)v；
The sound velocity measuring device (3) is used for measuring the sound velocity in the air inlet pipeline of the sound velocity nozzle (4);
the verification control system is used for correcting the gas molar mass calculated from the initial gas components according to the sound velocity, and calculating the outflow coefficient C of the sonic nozzle (4) by using the corrected gas molar massd。
2. An arrangement according to claim 1, characterized in that the HPPP primary standard device (2) comprises a high pressure volume tube (5), a piston (6), a position sensor (7) and a timer;
the piston (6) does uniform reciprocating motion in the volume measuring section of the high-pressure volume pipe (5) in a free replacement or forced replacement mode;
the position sensor (7) and the timer are respectively used for recording the position variation of the piston (6) and the corresponding moving time.
3. The apparatus of claim 2, further comprising:
the temperature sensor (8) and the temperature transmitter (9) are arranged at the air inlet end of the sonic nozzle (4), and the temperature transmitter (9) is used for receiving a temperature signal measured by the temperature sensor (8);
set up and be in pressure sensor (10) and absolute pressure transmitter (11) of end are given vent to anger in high pressure volume pipe (5), and set up high pressure volume pipe (5) with at least one differential pressure transmitter (12) between sonic nozzle (4), absolute pressure transmitter (11) with at least one differential pressure transmitter (12) are used for the cooperative measurement the pressure of sonic nozzle (4) inlet end.
4. The device according to claim 3, characterized in that the temperature transmitter (9), the absolute pressure transmitter (11) and the differential pressure transmitter (12) are respectively connected with the verification control system to convert the temperature/pressure signal at the air inlet end of the sonic nozzle (4) into a standard electrical signal and transmit the standard electrical signal to the verification control system.
5. The device according to claim 4, wherein the standard electrical signal is a current signal and/or a voltage signal.
6. The arrangement according to claim 1, characterized in that the sound speed measuring device (3) is an ultrasonic flow meter.
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| CN201921128671.0U CN210036908U (en) | 2019-07-17 | 2019-07-17 | High-pressure natural gas flow primary standard device with adjustable sonic nozzle |
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| CN201921128671.0U CN210036908U (en) | 2019-07-17 | 2019-07-17 | High-pressure natural gas flow primary standard device with adjustable sonic nozzle |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111780835A (en) * | 2020-07-24 | 2020-10-16 | 安东仪器仪表检测有限公司 | Calibration method for high-efficiency liquid phase transfer liquid flowmeter |
| CN112067087A (en) * | 2020-08-13 | 2020-12-11 | 镇江市计量检定测试中心 | Gas flow standard device capable of adjusting centering of sonic nozzle |
| CN114577312A (en) * | 2022-05-06 | 2022-06-03 | 南京深度系统工程有限公司 | Loop detection device containing multistage standards and online calibration method of standard |
-
2019
- 2019-07-17 CN CN201921128671.0U patent/CN210036908U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111780835A (en) * | 2020-07-24 | 2020-10-16 | 安东仪器仪表检测有限公司 | Calibration method for high-efficiency liquid phase transfer liquid flowmeter |
| CN112067087A (en) * | 2020-08-13 | 2020-12-11 | 镇江市计量检定测试中心 | Gas flow standard device capable of adjusting centering of sonic nozzle |
| CN112067087B (en) * | 2020-08-13 | 2021-04-13 | 镇江市计量检定测试中心 | Gas flow standard device capable of adjusting centering of sonic nozzle |
| CN114577312A (en) * | 2022-05-06 | 2022-06-03 | 南京深度系统工程有限公司 | Loop detection device containing multistage standards and online calibration method of standard |
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Effective date of registration: 20200814 Address after: 100728 Beijing, Chaoyangmen, North Street, No. 22, No. Patentee after: China Petroleum & Chemical Corp. Address before: 430073 No. 126 Optics Valley Avenue, East Lake New Technology Development Zone, Wuhan, Hubei Patentee before: METERING RESEARCH CENTER, NATURAL GAS BRANCH OF CHINA PETROLEUM AND CHEMICAL Corp. |
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