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 "Flow Measurement Technology - The Next Ten Years" J.E. Gallagher, P.E., Savant Measurement Corporation Ph: 281-360-6594 Fax: 281-360-9187 "To Accomplish Great Things, We Must Not Only Act But Also Dream, Not Only Plan But Also Believe" - Anatole France For a copy of full paper contact Omni Flow Computers, Inc. or Savant Measurement Corporation direct. GLOBAL OUTLOOK The global economy, the political events in the Middle East, Eastern Europe, the European Community's (EC) unification, the Commonwealth of Independent States (IS) and the USA’s regulatory atmosphere continues to drive the energy industry. Today even the best-managed companies are transforming their cost structures, and companies that fail to do likewise probably won't survive as independent companies. More consolidations can be expected in this decade for companies that do not adapt to the economic realities of a mature business. As energy consumers, the USA and Western Europe remain at the heart of the world energy drama. While they continue to exert great influence, many of the levers of power are now found in the Middle East, South America, Northern Africa, East Asia and, in the next century, the CIS. Competition among the sources of energy will grow as a result of environmental legislation, market forces and capital investments. The future energy situation can be stated simply - Energy demand will continue to grow steadily with the economies of the world. Alternative energy sources will be developed as a result of economics and the environment. Due to these global pressures, the future for flow measurement and quality assurance technology is bright. FLOW MEASUREMENT TECHNOLOGY The industry has only scratched the technology surface. Technology is the key that starts the economic engine. Willingness to work together globally is the engine. The resources that we apply to the task is the fuel that runs the engine and makes all things work. Instrumentation is selected based on its technical and commercial specifications. Usually the selection process considers only the instrument's capital cost and not the full cost of ownership over the its lifetime. The total cost of ownership consists of the initial capital, commissioning, training, spare parts, maintenance and calibration costs for the lifetime of the equipment. The full cost is several times the initial capital investment and should be the deciding factor in equipment selection. The technical selection - accuracy, repeatability, drift, ease of calibration as well as reliability indirectly affects the cost of ownership. Proper installation and application of flowmeters are two of the most significant parameters in the measurement chain. These parameters influence the factors mentioned above and are neglected in most assessments. The misapplication of any device brings the wrath of field personnel on the operating company's engineering staff - as it should! More effort is required by the user community to match their expectations with reality. The selection, installation, operation and maintenance of quality equipment, if properly performed, is almost never discussed by operating personnel. Modularization of discrete instrumentation is a key to success in the future. While some users have proposed the combination of all measurement instrumentation into a single control, computing, totalization, and communications device, this is obviously incorrect. Discrete functions will persist in order to satisfy performance, security, auditability and technology requirements. PRIMARY FLOW DEVICES The future vision of primary flow devices is clear and defined. The vision consists of "smart" flowmeters, new flowmeters, in situ calibration or central calibration technology for both incompressible and compressible fluids. Improved Friends and New Tools Primary flow devices can be grouped into energy additive or energy extractive classes. Further subclasses are grouped by the sensing technology. With the application of microchip technology into smart transmitters, sophisticated flow computers, personal computers, computational fluid dynamics (CFD), thermal anemometry (TA) probes (i.e. hot wire, hot film, x-wire), laser doppler velocimetry or anemometry (LDV/LDA), and characterization of flow meters in real time, large steps toward lowering the flow measurement uncertainty is possible. These "new" tools are providing significant advances in the refinement of existing metering equipment as well as the birth of new technology. Virtual reality meter station design will become a design tool. Artificial intelligence software combines with real time networking of metering facilities will create a new plateau of loss performance and problem identification. Flow Conditioners All inferential flowmeters are subject to the effects of velocity profile, swirl and turbulence structure approaching the meter. The meter calibration factors or empirical coefficients calculated from the discharge of coefficient equations are valid only if similarity exists between the metering installation and the experimental data base. These parameters should not be significantly different from those at the time of meter calibration, or from those which existed in the empirical coefficients of discharge data base. Technically this is termed the Law of Similarity. Many piping configurations and fittings generate disturbances with unknown characteristics. Even a simple elbow can generate very different flow conditions from "ideal" or "fully developed" flow. In reality, multiple piping configurations are assembled in series generating complex problems for standard writing organizations and flow metering engineers. The problem is to minimize the difference between "real" and "fully developed" flow conditions on the selected metering device thus maintaining the low uncertainty required for fiscal applications. For clarity, we will refer to this as "pseudo-fully developed" flow. A method to circumvent the influence of the fluid dynamics (swirl, profile and turbulence) on the meter's performance is to install a flow conditioner in combination with straight lengths of pipe to "isolate" the meter from upstream piping disturbances. Of course, this isolation is never perfect. After all, the conditioner's objective is to produce a "pseudo-fully developed" flow. The problems associated with installation effects of flowmeters have been with us a long time. Pragmatic solutions have evaded our industry due to our limited insights into the "real" flow field. Experiments over the last ten years have shed light on increasing our insights. In the USA, Canada and EC, scientists have recently conducted installation effects research on turbine, orifice and ultrasonic flowmeters. This data measured the meter's performance as a result of interaction with the near term flow field. With this insight, isolating flow conditioners have been developed which virtually eliminate piping induced flow disturbances. Smart Flowmeters With the application of microchip technology, large steps towards lowering flow metering uncertainties are possible due to the advent of sophisticated flow computers, personal computers, and characterization of flow meters in real time. These "new" tools are providing significant advances in the refinement of existing metering equipment as well as the birth of new technology. The application of Statistical Quality Control (SQC) techniques is viable today. By using serial meters of differing technology, it is possible to monitor the performance of each flowmeter separately as well as the ratio (or difference) of the two meters. The user should be able to discern when one of the devices is in need of repair. Additionally, each meter should be equipped with predictive performance software as a function of Reynolds number or other appropriate correlating parameters. The objective is to discern systematic bias shifts between the devices at a level that is acceptable to the economic value of the commodity transferred between the parties. Ultrasonic Flowmeters For incompressible fluids, the ultrasonic flowmeter is fast approaching the performance levels of custody transfer flowmeters (CTMs). Tests are currently being conducted in the USA on the application of new platform of ultrasonic flowmeters for line integrity purposes. For compressible fluids, experiments conducted by GERG and GRI indicate the viability of this technology to natural gas applications. To date, additional development effort is needed in the electronic packages associated with these devices and installation effects biases. The future looks promising. Coriolis Flowmeters One of the most unique flowmeters introduced in the last decade is the coriolis meter. This device measures the total mass as a function of the rotational forces exerted on a specially configured tube. Mixed results have been reported to date. However, it appears that this device will be viable in sizes up to 100mm. Velocity profile, velocity of sound, mechanical installation, and vibration are known to adversely affect the meter's performance. There is evidence that the coriolis meter may prove to be the future custody transfer meter for direct mass measurement of LPG and similar viscosity fluids. OTHER TOPICS INCLUDED ARE: In Situ and Central Calibration of meters Secondary Devices
Operational Enhancements
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