What are the performance characteristics of natural gas flow meters?
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Natural gas flow meters are highly accurate in terms of measurement precision, and they have a very wide range of applications. As the demand for users continues to grow, the production volume of flow meters also increases accordingly. Faced with a wide variety of flowmeters, users often don’t know how to make a choice. The specific analysis is as follows: 1. The performance of this instrument lies in its excellent accuracy and repeatability; it has a wide range of applications and is capable of outputting flow rates as well as various signals. 2. In terms of fluid properties, it exhibits good characteristics in terms of temperature, density, corrosion resistance, and specific heat capacity, and is capable of handling pulsating flows and multiphase flows, among others. 3. There are certain considerations to keep in mind when installing this type of flow meter, such as the diameter of the pipeline, the power supply, and the direction of flow. 4. It can operate without being affected by the environment, and it has low requirements regarding temperature, humidity, and electromagnetic factors. 5. When selecting a flow meter, factors such as its installation cost and service life should be taken into consideration. Flow metering is one of the components of metrological science and technology, and it is closely related to the national economy, national defense construction, and scientific research. Doing this work well plays an important role in ensuring product quality, improving production efficiency, and promoting the development of science and technology. Especially in today’s era of energy crises and an increasing level of automation in industrial production, the significance and role of flow meters in the national economy have become even more evident.
Media with a single component that does not change are easy to measure
Bro, can you let the tech team post it? How to choose a natural gas flow meter? Who knows how to choose? What kind of flow meter is this natural gas flow meter? Turbine? Vortex street? Orifice plate? Thermal?
Currently, the mainstream options are turbine flowmeters and ultrasonic flowmeters. Natural gas has been completely ruined. . . An ultrasonic device costs at least over 100,000. I just chuckled too. It is said that using differential pressure to measure natural gas results in a too narrow range, which is not conducive to accurate measurement.
Currently, the mainstream options are turbine flowmeters and ultrasonic flowmeters. Natural gas has been completely ruined. . . An ultrasonic device costs at least over 100,000. I just chuckled too. It is said that using differential pressure to measure natural gas results in a too narrow range, which is not conducive to accurate measurement. In natural gas metering, accuracy is a key consideration: ultrasonic flowmeters achieve an accuracy of 0.5%, while turbine flowmeters offer 1% accuracy. As for differential pressure measurement, the conventional method involves using orifice plates, but whose accuracy is even lower. In China, orifice plates were used around fifteen years ago; nowadays they are hardly used at all. In some relatively backward areas, orifice plates are still used for metering, but they are no longer the standard approach
This post was last edited by cqdfwy on 2018-2-5 at 14:47. A large part of the United States uses orifice meters for measurement – can you say that’s outdated? Orifice plate flowmeters used for measuring natural gas are quite common in the natural gas industry. What’s different is that they aren’t the ordinary orifice plate flowmeters we usually refer to; rather, they are orifice plate flowmeters that comply with the requirements specified in GBT 18603 \"Technical Requirements for Natural Gas Metering Systems\" and GBT 21446 \"Measurement of Natural Gas Flow Using Standard Orifice Plate Flowmeters\". These flowmeters consist of standard orifice plates combined with advanced orifice plate valve assemblies (which allow for the replacement of the orifice plate units while the system is still in operation, without interrupting gas flow), along with a flow computer. In addition to the usual temperature and pressure compensation functions, they also have other more sophisticated features, such as correction for the compressibility factor, and adjustments for the effects of medium temperature on the orifice plate and pipeline dimensions (for specific details, see the two standards mentioned above) ； The use of ultrasonic flowmeters in the natural gas industry is still subject to considerable controversy. This is because ultrasonic flowmeters are typically used for measuring flow rates in large pipelines, where high accuracy and reliability are required. Moreover, since these flowmeters can be affected by acoustic noise, there are certain requirements regarding the flow velocity in the pipeline as well as the length of straight sections; when the actual conditions on site do not meet these requirements, measurement failures can occur ； In addition to the orifice flow meters, turbine flow meters, and ultrasonic flow meters mentioned earlier, natural gas metering also makes use of rotameter flow meters and vortex swirl flow meters. For the metering of compressed natural gas (CNG) and liquefied natural gas (LNG), Coriolis mass flow meters are employed (as density is a critical factor; they cannot be used for ordinary low-pressure natural gas). There are also other situations where vortex street flow meters might be chosen (for use in factories where no precise metering is required), as well as thermal mass flow meters (suitable for natural gas with fixed composition and no water content), which can meet their specific requirements as well.
A large part of the United States uses orifice meters for measurement – can you say that’s outdated? -- I’m not really sure about this – I don’t have any say in it. However, Emerson’s gas ultrasonic flowmeters hold a significant market share in the United States. As far as I know, Emerson’s advanced orifice plates were very popular and well-regarded over a decade ago, but they now produce such flowmeter systems less often (perhaps they’ve stopped manufacturing them or been sold off). When asking for information regarding their advanced orifice plates in China, the response time is very slow. Orifice plate metering has been largely replaced by ultrasonic flowmeters; in my opinion, it’s a matter of accuracy – conventional orifice plate meters have an accuracy of 1% to 2%, while ultrasonic flowmeters can achieve an accuracy of 0.5%. Moreover, calibration requirements apply to all gas trading meters. For ultrasonic flowmeters, specialized institutions both domestically and abroad carry out calibration; only with a certificate can they be used for trade measurement. In contrast, orifice plates basically do not require calibration, which restricts their development. I’m referring to some relatively backward regions where orifice plate metering is still used – I’ve encountered projects in such places such as Egypt and Ethiopia. In the projects from the 1990s, orifice plates were used for measurement; now, even when making further purchases, orifice plates are still required. However, after communicating with the clients, it is usually decided to use ultrasonic flowmeters instead. Orifice plate flowmeters used for measuring natural gas are quite common in the natural gas industry. What’s different is that they aren’t the ordinary orifice plate flowmeters we usually refer to; rather, they are orifice plate flowmeters that consist of standard orifice plates (in compliance with GBT 18603 – Technical Requirements for Natural Gas Metering Systems and GBT 21446 – Measurement of Natural Gas Flow Using Standard Orifice Plate Flowmeters), advanced orifice plate valve assemblies that allow for the replacement of the orifice plates online without shutting down the flow of gas, and a flow computer. Such flowmeters not only have the usual temperature and pressure compensation functions but also additional advanced functions, such as correction for the compressibility factor and adjustments for the effect of medium temperature on the size of the orifice plates and pipes (for specific functions, see the two standards mentioned above) ； Advanced orifice plate flowmeters – I know that Emerson’s advanced orifice plate models are of high quality in China. There are still some of these in places like Xinjiang, but they are gradually being replaced by gas ultrasonic flowmeters. The use of ultrasonic flowmeters in the natural gas industry is still subject to considerable controversy. This is because ultrasonic flowmeters are typically used for measuring flow rates in large pipelines, where high accuracy and reliability are required. Moreover, since these flowmeters can be affected by acoustic noise, there are certain requirements regarding the flow velocity in the pipeline as well as the length of straight sections; when the actual conditions on site do not meet these requirements, measurement failures can occur ； ------I haven’t heard of any disputes, but I have encountered issues related to audio noise interference. This is largely related to the design; in particular, when there are pressure-regulating valves upstream and downstream of the pipes, it’s easy to encounter problems if no noise-reduction measures are taken. In China, the largest diameter for measuring pipes is DN400, while the smallest diameter available is DN80. For trade-level measurement, ultrasonic flow meters of DN80 size are only available from SICK and Elster; for DN50 pipes, turbine flow meters are generally used. In addition to the orifice flow meters, turbine flow meters, and ultrasonic flow meters mentioned earlier, natural gas metering also makes use of rotameter flow meters and vortex swirl flow meters. For the metering of compressed natural gas (CNG) and liquefied natural gas (LNG), Coriolis mass flow meters are employed (as density is a critical factor; they cannot be used for ordinary low-pressure natural gas). There are also other situations where vortex street flow meters might be chosen (for use in factories where no precise metering is required), as well as thermal mass flow meters (suitable for natural gas with fixed composition and no water content), which can meet their specific requirements as well. For the measurement of gas trade in pipelines, for pipes larger than DN100, ultrasonic flowmeters are commonly used with an accuracy of 0.5%; turbine flowmeters typically have an accuracy of 1%. Rotameter flowmeters are generally used for measuring city gas supply to end-users such as restaurants and similar establishments. Mass flow meters offer the best accuracy; some can reach 0.2%, but they are expensive. They are generally used for measuring liquids and rarely for measuring gases in trade applications.
It seems you have a good understanding of the natural gas metering industry as well. It is an undeniable trend that orifice plate metering will be replaced by ultrasonic flow meters, but that doesn’t mean orifice plate metering is outdated As for the application of advanced orifice plate flowmeters, not to mention in more distant regions, they are widely used by CNPC and Sinopec in China, especially in the south. In the north, ultrasonic flowmeters are beginning to replace orifice plate flowmeters – I believe this is because the low environmental temperatures in the north make it more difficult to use orifice plate flowmeters, resulting in poorer performance. This is indeed the case. As for the accuracy of advanced orifice plate flowmeters, it is now possible to ensure an accuracy within 1%; in some cases it even reaches almost 0.5%. Can you say that such accuracy is inadequate? . Furthermore, advanced orifice plate flowmeters used for trade measurement require on-site calibration; they are not left uncalibrated, as their accuracy must be guaranteed – otherwise, how can they meet the requirements of trade measurement?
Imported A+K orifice plates have been used for measuring natural gas; the sets are supplied complete, with temperature and pressure compensation. At the time of installation, there was a 3% deviation compared to the vortex flow meters used in the oil field, but this deviation remained stable. After data collection on-site for correction, the system has been in stable operation for 3 years now, with good performance. But it’s really expensive, it’s really expensive, it’s really expensive (important things are said three times).