CN108709609A - A kind of natural gas big flow is real to flow calibrating installation and method - Google Patents

Abstract

The invention discloses a kind of natural gas big flow, stream calibrating installation and method, the device include the first header in fact（3）With the second header（11）, first header（3）With air inlet（1）It is connected, the first header（3）It is connected with the detection pipeline that 4 tunnels are set up in parallel, the detection pipeline other end is connected to the second header（11）；Second header（11）It is also associated with verification table position（13）, the verification table position（13）It is connected to third header（12）On, third header（12）It is connected to exhaust outlet（10）, wherein air inlet（1）With the second header（11）Between be also associated with small flow section detection pipeline, be equipped with rectifier successively on small flow section detection pipeline（4）, turbine flowmeter（6）And rotz flowmeter（7）, rectifier is equipped on the detection pipeline successively（4）, ultrasonic flowmeter（5）And turbine flowmeter（6）.Long-time stability of the present invention are high, improve systematic jitters and price is lower.

Description

A real flow verification device and method for large natural gas flow

technical field

The invention belongs to the field of natural gas metering, and in particular relates to a large-flow real-flow verification device and method for natural gas.

Background technique

At present, domestic natural gas custody transfer flowmeters such as ultrasonic flowmeters, turbine flowmeters, etc. (inspected flowmeters) all use the standard table method (working standard) for real-flow compulsory verification and calibration, and the system uncertainty of the working standard can reach 0.33 %, the standard table adopts 0.25 high-precision gas turbine flowmeter. For the real-flow mandatory verification and calibration of the working-level standard meter, the secondary device composed of parallel critical flow nozzles is mainly used for real-flow verification. The system uncertainty of the secondary device can reach 0.25%. The critical flow nozzle of the secondary device is subjected to real-flow compulsory verification by the primary standard of the mt method (system uncertainty can reach 0.1%~0.05%), forming a perfect value transfer system:

The working level standards of domestic natural gas measurement and verification stations are composed of one or more sets of parallel high-precision turbine flowmeters, and each path also includes verification flowmeters, straight pipe sections, rectifiers, expanders and electric forced sealing ball valves for corresponding pipelines. According to the flow points required by the flowmeter to be tested, select different working-level standard flowmeters for combination, as shown in Figure 2.

According to the measurement range of the flowmeter to be verified (the flow range of 50mm~300mm is about 10~8000 m ³ /h), the working level device needs to select different caliber turbine flowmeters and determine the number of turbines of each caliber. At present, the domestic working-level standard turbine flowmeters mainly use three calibers of 250mm (130~2500 m ³ /h), one 150mm (50~500 m ³ /h) and one 80mm (20~2500m ³ /h) Combined, the full range can be used to verify the tested flowmeter of 50mm~300mm (10~8000m ³ /h).

But there are following problems in the prior art:

1) During small flow verification, the large pipe volume between the working-level standard flowmeter and the flowmeter to be tested will significantly increase the uncertainty of the entire verification system. Therefore, there is a large pipe volume effect of the downstream header of the working standard between the small-caliber turbine flowmeter responsible for the verification of the small flow section and the flow meter to be tested in the verification of the working standard.

2) According to the current setting of domestic working-level standards, a turbine flowmeter with a diameter of 80mm is usually selected as a small-caliber standard flowmeter. Due to the structural characteristics of the turbine flowmeter itself, the long-term stability of the small flow section is poor, that is, the long-term The deviation of the error variation is relatively large, and the stability is low.

3) The purging and venting pipelines of each working level standard need to be equipped with manual forced sealing ball valves, especially when multiple sets of turbine flowmeters are connected in parallel, the investment is relatively high.

Contents of the invention

The object of the present invention is to provide a natural gas large-flow real-flow verification device and method with high verification accuracy, strong long-term stability and low investment and maintenance costs.

The present invention adopts the following technical solutions to achieve the above object:

The present invention provides a large-flow natural gas real-flow verification device, which includes a first manifold and a second manifold, the first manifold is connected to the air inlet, and the first manifold is connected to multiple detection pipelines arranged in parallel. The other end of each detection pipeline is connected to the second header, and each detection pipeline is sequentially provided with a rectifier, an ultrasonic flowmeter and a turbine flowmeter from the first header to the second header; the second header is also connected with Verification station, the verification station is connected to the third manifold, the third manifold is connected to the exhaust port, wherein a small flow section detection pipeline is also connected between the air inlet and the second manifold, and the small flow section The detection pipeline includes two forced sealing ball valves at both ends, and a rectifier, a turbine flowmeter and a waist wheel flowmeter on the pipeline between the two forced sealing ball valves.

Further, a nitrogen purging pipeline is provided on the first manifold, and a venting pipeline is provided on the second manifold.

Further, a forced sealing ball valve is provided between the rectifier on the detection pipeline connected to the first manifold and the first manifold, and a forced sealing ball valve is also provided between the turbine flowmeter and the second manifold.

Further, the detection pipelines connected by the first manifold are divided into 4 routes, and the verification station is divided into 5 routes, in which there are two third manifolds in the downstream of the route, the two routes share a third manifold, and the other part of the verification station One path is directly connected to the exhaust port, and both ends of the verification platform are equipped with forced sealing ball valves.

Further, the diameters of the turbine flowmeters and ultrasonic flowmeters in the detection pipelines in the three paths are both 250mm, and the diameters of the turbine flowmeters and ultrasonic flowmeters in the paths are both 50mm. The diameters of the turbine flowmeter and the waist wheel flowmeter on the detection pipeline of the small flow section are both 100mm.

Further, the second manifold is also connected with a secondary standard device, and the secondary standard device is connected to the exhaust port.

Further, the diameters of the pipelines of the five stations of the verification station are 250mm, 300mm, 200mm, 50mm, and 100mm respectively.

A real-flow verification method for large flow of natural gas. When verification is required, install the flow meter to be checked on one of the verification benches according to the caliber of the flow meter to be checked, and then open the valve connected to the first manifold according to the range of the flow meter to be checked. One or more pipelines in the detection pipeline and the detection pipeline of small flow section are verified, and then enter the path where the flowmeter to be tested is installed in the verification platform, and then discharged to the gas outlet through the third manifold or directly through the verification platform to the gas outlet. air outlet

The present invention has the following beneficial effects:

(1) The detection pipeline of the small flow section is independent of the other 4 detection pipelines. The upstream directly takes gas from the air inlet, and the downstream is connected to the outlet of the second manifold. The verification is carried out for small-caliber flowmeters with a diameter of less than 100mm, which reduces the intermediate pipe volume during the verification of small-caliber flowmeters. The independent verification of small-caliber flowmeters with a diameter of less than 100mm can reduce the pipe volume by about 2.54m ³ and improve the system uncertainty. .

(2) A waist wheel flowmeter (100mm) is used to replace the original turbine flowmeter (80mm) in the detection pipeline of the small flow section. The flow range is 5~400 m ³ /h, the measuring range is wider, and the long-term stability is better. The corresponding verification flowmeter is a turbine flowmeter (100mm); the remaining 4 detection pipelines are turbine flowmeters (3 250mm, 1 150mm), and the flow ranges are 130~2500 m ³ /h and 50~500 m ³ /h, and the corresponding verification flowmeters are ultrasonic flowmeters (3 sets of 250mm and 1 set of 150mm); the total flow range is 10~8000 m ³ /h, which can meet the full range inspection of 50mm~300mm flowmeters.

(3) Simplify the venting process settings of each pipeline, reduce 50mm forced sealing valves and 5 stop valves each, simplify the nitrogen injection process settings of each pipeline, reduce 50mm forced sealing valves and 4 stop valves each, and simplify each pipeline expander Set up and cancel 5 sets of retractors, reducing investment by about 1.26 million yuan. Instead, only one nitrogen purge line is set at the first header, and one vent line is set at the second header.

Description of drawings

Fig. 1 is a schematic diagram of the present invention;

Fig. 2 is a schematic flow chart of a traditional natural gas large-flow real-flow verification device.

In the figure 1. Air inlet; 2. Nitrogen purge pipeline; 3. First header; 4. Rectifier; 5. Ultrasonic flowmeter; 6. Turbine flowmeter; 7. Waist wheel flowmeter; 8. Vent pipeline; 9. Secondary standard device; 10. Exhaust port; 11. Second header; 13. Verification platform; 14. Forced sealing ball valve; 15. Expander.

Detailed ways

【Example 1】

As shown in Figure 1, it includes a first manifold 3 and a second manifold 11, the first manifold 3 is connected to the air inlet 1, and the first manifold 3 is connected to multiple detection pipelines arranged side by side, each The other ends of the detection pipelines are all connected to the second manifold 11, and each detection pipeline is provided with a rectifier 4, an ultrasonic flowmeter 5 and a turbine flowmeter 6 in sequence from the first manifold 3 to the second manifold 11; The pipe 11 is also connected with a verification platform 13, and the verification platform 13 is connected to the third manifold 12, and the third manifold 12 is connected to the exhaust port 10. It is characterized in that: the air inlet 1 is connected to the second manifold. A small flow section detection pipeline is also connected between the pipes 11. The small flow section detection pipeline includes two forced sealing ball valves 14 located at both ends, and a rectifier 4, a turbine flowmeter 6 and a rectifier located on the pipeline between the two forced sealing ball valves 14. Waist wheel flowmeter7.

A forced sealing ball valve 14 is provided between the rectifier 4 on the detection pipeline connected to the first manifold 3 and the first manifold 3 , and a forced sealing ball valve 14 is provided between the turbine flowmeter 6 on the detection pipeline and the second manifold 11 .

The turbine flowmeter 6 and ultrasonic flowmeter 5 in the 4-way detection pipeline, the diameters of the turbine flowmeter 6 and the ultrasonic flowmeter 5 in the 3-way are 250mm, and the diameters of the turbine flowmeter 6 and the ultrasonic flowmeter 5 in the 1-way are 150mm .

The diameters of the turbine flowmeter 6 and the waist wheel flowmeter 7 on the detection pipeline of the small flow section are both 100mm.

The detection pipelines connected to the first manifold 3 are divided into 4 paths.

Among them, the first manifold 3, the second manifold 11, the 4-way parallel detection pipeline and the small flow section detection pipeline are collectively called the working-level standard device, and the gas enters the working-level standard device from the gas connection port 1, and then enters the verification platform In 13, the verification platform 13 is used to install the flow meter to be tested, and finally the gas is discharged from the verification platform 13 to the exhaust port 10, and finally discharged.

And the detection pipeline of the small flow section is independent from the 4-way detection pipeline, and is directly connected to the air inlet 1 and the second manifold 11, so that it can not only participate in the verification work of the large-caliber flowmeter to be tested, but also can independently test the small-caliber flowmeter below 100mm. The tested flowmeter is verified, and when the small-caliber tested flowmeter below 100mm is verified separately, the pipe volume can be reduced by about 2.54m ³ , which improves the system uncertainty.

In the multi-channel parallel detection pipeline, the turbine flowmeter 6 on the pipeline is used as a working level standard meter, three of which have a diameter of 250mm and one of which is 150mm, and the flow ranges of the two are 130~2500 m ³ /h and 50~500 m ³ /h. The ultrasonic flowmeter 5 on the pipeline is used as a verification flowmeter, three of which have a diameter of 250mm and one of which is 150mm, with a total flow range of 10-8000 m ³ /h, which can meet the full-scale inspection of a 50mm-300mm flowmeter. Wherein the turbine flowmeter 6 and the ultrasonic flowmeter 5 with the same diameter are located in the same road.

In addition, as shown in FIG. 2 , the current domestic devices all use the turbine flowmeter 6 as the working level standard meter, but the small-diameter turbine flowmeter 6 has poor long-term stability.

By comparison, the turbine is a velocity flow meter. First, there is friction between the blade and the shaft. When the small flow rate is below a certain critical point, the gas is greatly affected by the friction. There is a certain degree of difference between the measured blade speed and the actual fluid flow rate, and the measurement accuracy is poor. ; Second, the velocity flowmeter is greatly affected by the Reynolds number (Re=ρvd/µ). When the diameter d is smaller, the gas Reynolds number is smaller, the flow state tends to be laminar, and the balance and reproducibility are poor. long-term stability is poor.

The waist wheel is a positive displacement flow meter. In the small flow section, it is less affected by friction and Reynolds number, and has better long-term stability. ^The annual flow error variation does not exceed 0.05%. The error is small (-0.15~+0.25%), and the linearity is high; the stability is good, which is beneficial to the correction of the flowmeter error.

Therefore, the working level standard meter in the independent small flow section detection pipeline adopts the waist wheel flowmeter 7, which has a diameter of 100mm, a flow range of 5~400 m ³ /h, a wider range, better long-term stability, and an annual flow error The amount of change shall not exceed 0.05%. The verification flowmeter on the line adopts the turbine flowmeter 6 of 100mm.

[Example 2]

As shown in FIG. 1 , a nitrogen purging pipeline 2 is provided on the first manifold 3 , and a venting pipeline 8 is provided on the second manifold 11 .

As shown in Figure 2, the nitrogen purge pipeline 2 and the vent pipeline 8 connected to the detection pipeline should be equipped with a forced sealing ball valve 14 to ensure zero leakage, and the investment of the forced sealing ball valve 14 is more expensive than ordinary ball valves. The sweeping pipeline 2 and the venting pipeline 8 are respectively arranged on the first manifold 3 and the second manifold 11, avoiding the forced sealing ball valve 14 of the nitrogen purging pipeline 2, the venting pipeline 8 and each detection pipeline. Costs are reduced while purging and venting functions can be realized.

At the same time, because the standard flowmeter is not often disassembled after installation, the present invention cancels the expander 15 on each detection pipeline.

In general, by simplifying the venting process settings of each pipeline, reducing the number of 50mm forced sealing valves and stop valves by 5 each, simplifying the process settings of nitrogen injection in each pipeline, reducing the number of 50mm forced sealing valves and stop valves by 4 each, and simplifying each pipeline For the configuration of expanders, 5 sets of expanders will be canceled, reducing the investment by about 1.26 million yuan.

[Example 3]

As shown in Figure 1, the verification station 13 is divided into 5 routes, of which two third manifolds 12 are arranged downstream of the 4 routes, and the two routes share a third manifold 12, and the other route of the verification station is directly connected to the exhaust port. 10 connection, both ends of the verification platform 13 are equipped with forced sealing ball valves 14.

The diameters of the pipelines of the 5 stations of the verification station 13 are 250mm, 300mm, 200mm, 150mm and 100mm respectively.

Among them, there are 5 paths in the verification platform 13, which are used to install the tested flowmeters of different calibers. According to the scope of the flowmeter to be tested, select several flow points to be verified according to the requirements of the verification regulations, and correspondingly open the pipelines that need to be combined according to the working level standards. The selection of specific combinations is shown in Table 1.

Table 1 Combination selection list of working level standard flowmeter

For example, as shown in No. 1, when the caliber of the flowmeter to be tested is 50mm~100mm, and the measurement range of the detection point is (10~250) m ³ /h, only the small flow detection pipeline with a standard meter caliber of 100mm is used.

As shown in No. 2, when the caliber of the flowmeter to be tested is 80mm~100mm, and the measurement range of the detection point is (250~400) m ³ /h, the 4-way detection pipeline is used, and the standard table is that the caliber of the turbine flowmeter 6 is 150mm that way.

As shown in No. 7, when the caliber of the flowmeter to be tested is 150mm~200mm, and the measurement range of the detection point is (1600~3200) m ³ /h, in the detection pipeline, the 3-way standard meter, that is, the caliber of the turbine flowmeter 6 is 2 way in 250mm.

【Example 4】

As shown in FIG. 1 , the second manifold 11 is also connected to a secondary standard device 9 , which is connected to the exhaust port 10 .

The second manifold 11 can also be connected to the existing secondary standard device 9 to facilitate secondary standard detection when needed, and the secondary standard is discharged from the exhaust port 10 after detection.

To sum up, when verification is required, install it to one of the verification stations 13 according to the caliber of the inspected flowmeter, and then open and connect to the first manifold 3 according to Table 1 according to the range of the inspected flowmeter. One or more pipelines in the detection pipeline of the small flow section and the detection pipeline of the small flow section are tested, and then enter the test station 13 where the flow meter to be tested is installed, and then discharged to the gas outlet 10 through the third manifold 12 or directly through the test Station 13 discharges to air outlet 10.

During the verification, natural gas enters from the air inlet 1. According to Table 1, when a 100mm working level gauge is required, the natural gas directly enters the verification station 13 through the small flow section detection pipeline, and the small flow section detects the waist wheel in the pipeline. The flowmeter 7 is verified, and the turbine flowmeter 6 is checked. At this time, as shown in the serial number 1 in Table 1, the caliber of the flowmeter to be tested is 80-100mm, and the natural gas directly enters from the detection pipeline of the small flow section without passing through the second header 11. Check the pipeline with a diameter of 100mm in the platform 13, and then the natural gas is discharged from the gas outlet 10. As shown in No. 4, when the caliber of the flowmeter to be tested is 150-200mm, the natural gas enters the second manifold 11 through the detection pipeline of the small flow section, and then enters the path where the flowmeter to be tested is placed in the verification station 13, and then enters the first The tri-manifold 12 then exits through the exhaust port 10 .

When it is necessary to use a 150mm or 250mm working level meter, the natural gas enters the first header 3 through the air inlet 1, and one or more of the 4 verification pipelines are opened according to Table 1, and the turbine flowmeter 6 is used for verification. The ultrasonic flowmeter 5 is used as a check, and the natural gas enters the second manifold 11 after passing through the corresponding path, and then enters the path where the flowmeter to be tested is installed in the verification platform 13, then enters the third manifold 12 and then is discharged through the exhaust port 10.

Claims (8)

1. a kind of natural gas big flow stream calibrating installation, including the first header in fact（3）With the second header（11）, first header （3）With air inlet（1）It is connected, the first header（3）It is connected with the detection pipeline that multichannel is set up in parallel, detection pipeline is another per road End is connected to the second header（11）, pipeline is detected per road from the first header（3）To the second header（11）On successively be equipped with rectifier （4）, ultrasonic flowmeter（5）And turbine flowmeter（6）；Second header（11）It is also associated with verification table position（13）, the calibrating Platform position（13）It is connected to third header（12）On, third header（12）It is connected to exhaust outlet（10）, it is characterised in that：Wherein air inlet （1）With the second header（11）Between be also associated with small flow section detection pipeline, include being located at both ends on small flow section detection pipeline Two forced seal ball valves（14）, and positioned at two pressure seal ball-valves（14）Between rectifier on pipeline（4）, turbine flow Gauge（6）And rotz flowmeter（7）.

2. a kind of natural gas big flow according to claim 1 flows calibrating installation in fact, it is characterised in that：First header （3）It is equipped with nitrogen purge line（2）, the second header（11）It is equipped with blow-down pipe（8）.

3. a kind of natural gas big flow according to claim 1 flows calibrating installation in fact, it is characterised in that：First header （3）Rectifier on the detection pipeline of connection（4）With the first header（3）Between be equipped with forced seal ball valve（14）, turbine flow Meter（6）With the second header（11）Between also be provided with forced seal ball valve（14）.

4. a kind of natural gas big flow according to claim 1 flows calibrating installation in fact, it is characterised in that：First header （3）The detection pipeline of connection is divided into 4 tunnels, verification table position（13）5 tunnels are divided into, there are two third headers wherein 4 tunnel downstreams are set （12）Two-way shares a third header（12）, the another way of verification table position is directly and exhaust outlet（10）Connection, the verification table Position（13）Both ends are equipped with forced seal ball valve（14）.

5. a kind of natural gas big flow according to claim 1 flows calibrating installation in fact, it is characterised in that：The 4 tunnel detection Turbine flowmeter in pipeline（6）And ultrasonic flowmeter（5）, turbine flowmeter in 3 tunnels（6）And ultrasonic flowmeter（5）Directly Diameter is 250mm, the turbine flowmeter in 1 tunnel（6）And ultrasonic flowmeter（5）Diameter is 150mm；The small flow section inspection Turbine flowmeter on test tube line（6）And rotz flowmeter（7）Diameter is 100mm.

6. a kind of natural gas big flow according to claim 1 flows calibrating installation in fact, it is characterised in that：Second header （11）It is also associated with secondary standard device（9）, secondary standard device（9）It is connected to exhaust outlet（10）.

7. a kind of natural gas big flow according to claim 4 flows calibrating installation in fact, it is characterised in that：The verification table position （13）5 road platform position pipe diameters be respectively 250mm, 300mm, 200mm, 150mm, 100mm.

8. a kind of natural gas big flow flows calibration method in fact, it is characterised in that：When needing calibrating, according to the mouth of tested flowmeter Diameter attaches it in verification table position all the way, further according to the range of tested flowmeter, opens the detection being connected with the first header One or more pipeline in pipeline and small flow section detection pipeline is examined and determine, and stream is detected subsequently into being installed in verification table position Gauge all the way, after drain into gas outlet through third header or directly drain into gas outlet through verification table position.