Rotary meters are highly machined precision instruments capable of handling higher volumes and pressures than diaphragm meters. The meters are produced of four nominal sizes G1.6, G2.5, G4, G6 in three modifications: The shut-off valve eliminates the risk of gas contamination (for stoves not equipped with gas control system) and helps to cut off gas supply in case the gas consumer has run out of credit. (and, in fact, are often one or two pipe sizes smaller than the lines in which they are installed, which contributes to pressure drop). Flow Meters for High Pressure Such devices are based on two types of technology: (1) time of flight or transit time; and (2) cross correlation. This website uses cookies to improve your experience while you navigate through the website. The units built-in flow computer functionality also can calculate the speed of sound based on input data from pressure and temperature transmitters and a gas chromatograph (GC). The enormous value of gas involved makes accuracy essential. The flow computer receives volumetric flow measurement data from DP or ultrasonic gas meters, along with temperature and pressure, and calculates the flow rate. Four-channel ultrasonic gas flow meter Energoflow GF- 404 is specially designed for applications where very high accuracy is required, e.g. The meter creates a 'ping' with the transducer and measures the time elapsed before the sensor receives the sonic pulse. Ultrasonic gas flow meters Energoflow GFE-211 and GFE-212 are a brilliant example of genial engineering for achieving optimal solution for gas flow measurement in large pipes and in cases where installation of inline meters is technically or commercial not viable. Since they measure flowing density, coriolis meters can also infer gas flow rate at flowing conditions. Remote reading is becoming popular for gas meters. 2 0 obj These calculations depend in part on the ideal gas law and also require a gas compressibility calculation in order to account for the fact that real gases are not ideal. The accuracy is generally laid down in statute for the location in which the meter is installed. From the knockout pot, the gas flows to a dehydrator to remove water vapor and perhaps to a micro-membrane separator to remove excess CO2. The complex can be used for reliable measurement of volumetric data of various gaseous media for custody transfer applications. The initial installation and initialization of HORN Gas Meters are performed using standard IR-DA port with a connection to the nearest concentrator in a network (within a radius of 500 meters). To find out more about the cookies this site uses and how to delete them, please see the, Platinum Jubilee Statement from the IGEM President and CEO, Applies to inlet pressures exceeding 38 bar and not exceeding 100 bar. Varying temperature cannot be handled as easily, but some meters are designed with built-in temperature compensation to keep them reasonably accurate over their designed temperature range. ^O3$~U=1`RaF ]K4{y#W Htl:KgzaCjI.N"#:"-,P#L/d40(.b&KvDv]:mb2>)8Z3rF,\y@cPlv.RCcog1m\9^sx49(wun1#. Energoflow GFE-202 and GFE-201 are state-of-art ultrasonic gas flow meters designed for accurate and reliable measurement of flow velocity, volumetric flow rate and volume of gaseous substances (gases) transported through pipelines in the forward or reverse direction. Ultrasonic gas flow meters Energoflow GFE-211 and GFE-212 are a brilliant example of genial engineering for achieving optimal solution for gas flow measurement in large pipes and in cases where installation of inline meters is technically or commercial not viable. Penalties for uncertainty in fiscal measurement. Ultrasonic flowmeters measure volumetric flow rates. They feature wide turndown ratios and do not experience performance or calibration drift. 8, detail characterization. This article appearsin theApplied Automationsupplement forControl EngineeringandPlant Engineering. You may delete and block all cookies from this site, but parts of the site will not work. These locations generally provide the favorable conditions in which most flow measurement devices can operate with some degree of predictability and repeatability. Its important to note that shale gas, which is what is fueling the transformation of the energy industry, is different from conventional natural gas in several important ways. American Gas Association[1] covers the proper usage and installation of these meters, and it specifies a standardised speed-of-sound calculation which predicts the speed of sound in a gas with a known pressure, temperature, and composition. Orifice meters often do not handle a large range of flow rates. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. Advantages include standard volume flow accuracy of 0.35% to 0.5%, with 0.25% available, as well as negligible pressure drop and high turndown capability. The frequency of this vibration is determined by the overall density of the pipe (including its contents). The approximate number of meters per one concentrator ranges from 200 to 300 units. In addition, DP meters are sensitive to flow profile and require either a fairly long straight run or an upstream flow conditioner. An important feature of many ultrasonic meters is their built-in diagnostics, which enable them to detect the presence of liquids (two-phase flow), dirt buildup, blockage, and other problems. To measure either mass or volumetric flow, they must be corrected for density (mass) or temperature, pressure, and gas composition to obtain a standard reading. It is often done through an electronic pulse output mounted on the meter. %PDF-1.4 The only way to counter fouling in a DP meter is to send someone out periodically to inspect the orifice plate, which is expensive in terms of labor and can mean an interruption in production. <> A small internal turbine measures the speed of the gas, which is transmitted mechanically to a mechanical or electronic counter. The use of DP meters for custody transfer is governed by API 14.3/AGA3 in North America and ISO 5167 globally. They are however accepted and understood in industrial applications since they are easy to field-service and have no moving parts. Reference Rotary Gas Meters EFS-R are intended for installation on reference calibration rigs for calibration and verification of gas meters of any type with air as operating environment. For this reason, accurate and repeatable measurement of natural gas flow requires simultaneous measurement of several other variables, including pressure, temperature, density, and gas composition. Pressure is generally not a problem; the meter is simply installed immediately downstream of a pressure regulator and is calibrated to read accurately at that pressure. Orifice meters are a type of differential meter, all of which infer the rate of gas flow by measuring the pressure difference across a deliberately designed and installed flow disturbance. They also generate a medium-to-large pressure loss, and they are not as accurate as other technologies, such as gas turbine, ultrasonic, or Coriolis meters. They are, for example, a good fit for the inputs and outputs of cryogenic gas processing plants and for feeds to large industrial users such as power plants. Information is further received by the server in an encrypted form and decoded. Washington, DC: American Gas Association. This allows the meter to measure the flowing density of the gas in real time. Once the fluid begins to flow, however, the Coriolis force comes into play. During the last few years, there has been a tremendous increase in U.S. production of natural gas, much of it derived from fracking plays. Its interesting to note that while a Coriolis meter will give a density reading, in many markets, much of the accounting is done in terms of standard volume, which means it is still necessary to measure temperature and pressure, as well as gas composition. The volume of gas flow provided by a gas meter is just that, a reading of volume. Since then, the vast majority are now placed outside though there are a few exceptions especially in older cities. Flow measurement is critical at all points of the supply chain. Information garbling and hacking are impossible. The most elaborate types of ultrasonic flow meters average speed of sound over multiple paths in the pipe. According to the federal Energy Information Administration (EIA), dry natural gas shipments increased from 1 trillion ft3 in 2000 to 5 trillion ft3 in 2010, and production increased by a factor of 12 in one decades time. The other paths may be identical or similar, except that the sound pulses travel downstream. This is known by several names as the calorific value, heating value, or therm value. Here, three technologies: differential pressure (DP), ultrasonic (both of which measure volumetric flow), and Coriolis, which directly measures mass flow are discussed. [6] These sizes are typically 10Lt, 20Lt, 30Lt, 45Lt, or 60Lt, though smaller and larger sizes are available. If you aready have an account, please Login,
The most common are indicators that use multiple clock hands (pointer style) or digital readouts similar to an odometer, but remote readouts of various types are also becoming popular see Automatic meter reading and Smart meter. lines, and a Coriolis meter or an ultrasonic gas flowmeter can be a good choice here because of their large turndowns involved. The other is allocation, defined as "the transfer of goods between two points generally not governed by a buy/sell contract," while custody transfer is done under a contractual obligation between buyer and seller that may require adherence to accuracy, repeatability, linearity, or uncertainty standards defined by measurement standards such as American Gas Association (AGA), American Petroleum Institute (API), International Organization for Standardization (ISO), GOST (Russian equivalent to API), and so on. The rotational movement of the crank shaft serves as a primary flow element and may produce electrical pulses for a flow computer or may drive an odometer-like counter. While conversion of flow rates to standard volume is needed, the variability of shale gas makes it necessary to use a GC, which is the only way to be certain about the calorific value of the gas delivered. There is, in fact, an eight-path meter available that is essentially a pair of four-path meters in a redundant configuration. They usually are mandatory for custody transfer applications. 1 / 1 with optical port and built-in wireless modem; 0 / 0 without optical port and wireless modem. 4-channel Flow Meters for Applications Requiring Enhanced Accuracy DP meters are the choice here because they are simple and inexpensive. When the fluid within the displaced section is at rest, both the upstream and downstream portion of the displaced section will vibrate in phase with each other. All forms of fiscal measurement can be affected by product quality, fluid properties and composition, operating parameters, maintenance practices, and technology type. The quality of the gas is measured and adjusted for in each billing cycle. indicating emergencies, dispatcher actions. Reference Turbine Gas Meters EFS-T are intended for installation on reference calibration rigs for calibration and verification of gas meters of any type with air as operating environment. The Edinburgh New Philosophical Journal: Exhibiting a View of the , Volume 10. The use of ultrasonic meters for custody transfer is governed by AGA-9 and ISO/DIS 17089-1 (see Figure 6). He is a member of the AGA Transmission Measurement Committee, which is responsible for AGA 9: Measurement of Gas by Multipath Ultrasonic Meters. The complex can be used for reliable measurement of volumetric data of various gaseous media for custody transfer applications. While a Coriolis meter will provide information on gas density, the GC is still needed to obtain a number for Btus per pound; a GC is expensive and tends to be reserved for places where there is enough volume to justify its cost. Energoflow GFA-202 The concentrators transfer collected information to the online network by any available means including GPRS/GSM/3G/Ethernet. They have low turndown unless the orifice plate is changed. stream Coriolis flowmeters measure mass flow and density directly. This Standard covers the basic design principles and functions required of gas meter installations, This standard covers location, housings and compounds for flow rate exceeding 6 m3h-1 and inlet pressure up to and not exceeding 38 bar, This standard covers the fabrication, installation, testing and commissioning for flow rate exceeding 6 m3h-1 and inlet pressure up to and not exceeding 38 bar, This standard covers the operation and maintenance for flow rate exceeding 6 m3h-1 and inlet pressure up to and not exceeding 38 bar, This standard covers notices and labels for flow rate exceeding 6 m3h-1 and inlet pressure up to and not exceeding 38 bar, IGEM/GM/PRS/1 - Meter installation fittings, IGEM/GM/PRS/3 - Meter regulators for gas flow rates not exceeding 6 m3 h-1 and inlet pressures not exceeding 75 mbar, IGEM/GM/PRS/28 - Medium pressure single-stage regulators for gas flow rates not exceeding 6 m3 h-1, IGEM/GM/PRS/29 - Medium pressure two-stage meter regulators for gas flow rates, IGEM/GM/PRS/33 - Meter regulators of nominal diameter 32 mm and not exceeding 150 mm and for inlet pressures not exceeding 75 mb, Medium pressure meter installation kits for flow rates not exceeding 6 m3 h-1, This specification covers pre-assembled 6m3 h-1 low pressure meter installation kits. Orifice meters are a very commonly used type of meter, and because of their widespread use, the characteristics of gas flow through an orifice meter have been closely studied. Flow Metering Complexes for Custody Transfer of Natural Gas. Any disagreement between the computed and measured values indicates a problem somewhere in the system. See other articles from the supplement below. Diaphragm gas meters are positive displacement meters. With each turn, they move a specific quantity of gas through the meter. In addition, most Coriolis meters are available with self-diagnostics that can detect when they are beginning to foul (they exhibit a change in baseline frequency response) without having to send someone out to open and examine the meter. Gas meters measure a defined volume, regardless of the pressurized quantity or quality of the gas flowing through the meter. otherwise Register here, IGEM House26 & 28 High StreetKegworthDerbyDE74 2DAUnited Kingdom, t: +44 (0)1509 678 150e: general@igem.org.ukCharity No: 214011Vat No: 674772885, This site uses cookies to store information on your computer, to improve your experience. When choosing a flowmeter supplier, it is wise to consider a supplier that can provide as many pieces of the puzzle as possibleincluding multiple meter typesto gain unbiased advice on the most appropriate equipment for each step in the supply chain from the wellhead to the ultimate customers. AGA Report No. The ultrasonic meter constantly measures the speed of sound in the flowing gas. The flow computer also acts as a record keeper recording date and time, instantaneous, hourly, and daily data. Within the meter, two figure "8" shaped lobes, the rotors (also known as impellers or pistons), spin in precise alignment. Inexpensive varieties of ultrasonic meters are available as clamp-on flow meters, which can be used to measure flow in any diameter of pipe without intrusive modification. The calorific value of natural gas can be obtained using a process gas chromatograph, which measures the amount of each constituent of the gas, namely: Additionally, to convert from volume to thermal energy, the pressure and temperature of the gas must be taken into consideration. Click here to start this process. Gas Meter HORN is designed to measure the volume of natural. A coriolis meter is usually one or more pipes with longitudinally or axially displaced section(s) that are excited to vibrate at resonant frequency. In addition, they generally are not available in sizes larger than 16 in. Reference Rotary Gas Meters EFS-R Four-channel ultrasonic gas flow meter Energoflow GF- 404 is specially designed for applications where very high accuracy is required, e.g. Clamp-on meters are available for measuring liquid flow as well. A gas meter is a specialized flow meter, used to measure the volume of fuel gases such as natural gas and liquefied petroleum gas. The server receives instant notifications in case of emergency situations, deviations of the supply voltage or when trying to access files using the IR-DA port. Energoflow GFE-211, GFE-212 Inlet pressure exceeding 38 bar and not exceeding 100 bar, IGEM/GM/5 Edition 3 - Electronic gas volume conversion systems, IGEM/GM/6 Edition 2 - Non-domestic meter installations. to design, engineering and manufacture of flow-metering solutions and related products based on the modern ultrasonic technology. Any type of gas meter can be obtained with a wide variety of indicators. Such meters can be used to measure almost any dry gas including natural gas, nitrogen, compressed air, and steam. This standardised calculation compensates the quantity of volume as measured to quantity of volume at a set of base conditions. Utility customers are billed according to the heat available in the gas. These procedures give guidance on the design and usage of high accuracy meter installations of piped Natural Gas in a specific pressure range, such as compressor stations, This standard contains guidance on the appropriate installation and usage of systems designed to convert gas volume readings to base conditions, This standard extensively details the requirements for the installation and usage of gas meters used in a non-domestic setting, This Standard provides requirements for the selection, installation, inspection and maintenance of electrical equipment connected to gas meter installations, This standard covers the classification of dangerous areas, those in which explosive gas mixtures may be present, for gas metering equipment, Flow rate exceeding 6m3 h-1 and inlet pressure up to and not exceeding 38 bar. [3] However, the European Measuring Instrument Directive has harmonised gas meter errors across Europe and consequently meters manufactured since the directive came into force must read within 3%. And because shale gas wells are switched in and out, that composition can change in a matter of hours. A number of six-path and eight-path meters have been introduced, but research (Klaus Zanker, Letton Hall Group, and Tom Mooney, Emerson Process Management [now with BP]), "Limits on Achieving Improved Performance from Gas Ultrasonic Meters and Possible Solutions," presented at the 30th International North Sea Flow Measurement Workshop, Oct. 23-26, 2012) has shown that little is gained by exceeding four paths. At current gas prices, an error of 1% in measuring 300 million ft3 of gas per day can lead to a difference of about $2 million per year (see Figure 2). Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. ambient temperature from minus 25 to 70; humidity not more than 95 % at temperature not exceeding 35 and lower temperatures without condensation; atmospheric pressure from 84 to 106,7 kPa (from 630 to 800 mm Mercury); the highest operating pressure not exceeding 50 kPa. And because they measure speed of sound in the gas, they can help provide a sanity check on other instruments, such as gas chromatographs, and check the accuracy of mathematical conversion to standard pressure elsewhere in the system. In the UK, the permitted error for a gas meter manufactured prior to the European Measuring Instruments Directive[2] is 2%. The gas static pressure, density, viscosity, and temperature must be measured or known in addition to the differential pressure for the meter to accurately measure the fluid. A very commonly used compressibility calculation is American Gas Association Report No. You also have the option to opt-out of these cookies. Do you have experience and expertise with the topics mentioned in this content? In addition, a Coriolis meter can detect the onset of two-phase flow. The use of Coriolis meters for custody transfer is governed by AGA-11. From the satellite skid, the gathered gas goes to a knockout pot or sand trap where bulk liquids and particles are removed and then to a flowmetergenerally a DP meter as wellthrough a 6- or 8-in. Simple volumetric flow measurement technology is not the only consideration because the ultimate measurement-and what the customer pays for-is energy delivered. The length of each path is precisely measured in the factory. One of the cookies this site uses is essential for parts of the site to operate and has already been set. Managing challenges Each stage in the natural gas supply chain presents its own challenges and opportunities for gas flow measurement-either fiscal or custody transfer. The sudden appearance of liquids can indicate a problem with the separation equipment upstream of gas processing, while any ethanes or propanes that condense out of the natural gas flow downstream of gas processing are products that should have been separated for sale as liquids and indicate process issues with the gas processing plant. By Dan Hackett, Emerson Process Management, By using this website, you agree to our use of cookies. Coriolis meters are physically large, relatively expensive, and produce pressure drop (see Figure 3). Gas meters that exist in colder climates in buildings built prior to the 1970s were typically located inside the home, typically in the basement or garage. 9x'e;IyYT^/8:y,={aOT+ijM8~? We also use third-party cookies that help us analyze and understand how you use this website. While not the most accurate instruments available, they are acceptable for the purposes for which they are used, and the calculations for correcting to standard conditions are widely known. Turbine, rotary, and diaphragm meters can be compensated using a calculation specified in American Gas Association Report No. !HE`PL:hr S 1*!UN-4`<20IN3=o39p: D8;?$= '5/92-/+
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;}]>nW*AA American Gas Association Report No. They do not need pressure and temperature compensation for fluid properties. If the meter is found to be reading within limits, the consumer has to pay the costs of testing (and pay any outstanding charges). This works well as long as the system isnt pushed so hard that liquids or dirt are carried through into the flowmeter, which can reduce the orifice size and make the meter read high. First, it may contain less than 50% methane, compared to 85% for conventional gas. The meter then compares the difference between the upstream and downstream speeds to calculate the velocity of gas flow. However, the additional paths usually are provided as a separate flowmeter within the same flowmeter body as a means of checking the overall operation of the meter (see Figure 5). Turbine gas meters infer gas volume by determining the speed of the gas moving through the meter. An ultrasonic meter is very effective at detecting two-phase flow; the presence of liquids generally indicates a problem elsewhere in the system (or that the ultrasonic meter has been installed at the wrong location). Ultrasonic flow meters are more complex than meters that are purely mechanical, as they require significant signal processing and computation capabilities. Gas meters are required to register the volume of gas consumed within an acceptable degree of accuracy. It is mandatory to procure user consent prior to running these cookies on your website. These cookies will be stored in your browser only with your consent. As the gas moves toward delivery to users smaller than power plants or cryogenic gas plants, line sizes tend to decrease, at which point Coriolis meters begin to reappear. The exact sequence of steps in shale gas recovery and separation varies somewhat from place to place, but the following description gives the general idea. [7], The examples and perspective in this section. For this reason, they are generally restricted to applications in which pressure drop is of limited concern. Reference Turbine Gas Meters EFS-T To resume gas supply, the person using the equipment must press a special button or complete the procedure in any other prescribed manner. x#>_h^A|s@6LO=j)y`zX.:=K>/xw?