Measurement Library

Western Gas Measurement Short Course Publications (2007)

Western Gas Measurement Short Courses

Fundamentals Of The Basic Gas Laws
Author(s): Robert Bennett
Abstract/Introduction:
Science interprets nature in terms of matter and energy. Energy is defined as the capacity to do work. There are many types of energy such as heat energy, electrical energy, kinetic energy (energy of motion), and potential energy (intrinsic energy of an object due to the position of the object). Matter is the material of which the universe is composed and is defined as anything that occupies space and has mass. There are three normal states of matter - solid, liquid, and gas. Under certain conditions, most substances can be made to exist in any of the three states, i.e. water as steam, liquid, or ice. Solid matter is rigid, generally crystalline, and will exhibit a definite shape. Liquids will flow, assume the shape of the container they are stored, and considered to maintain a constant volume and density. Gaseous matter is much more difficult to qualify since it consists of widely separated molecules in rapid motion. The comparatively large distances between the molecules make it possible for one gas to accommodate molecules of another gas or be compressed to force the individual molecules closer together. Since the molecules are in constant motion, they will expand to fill any container and strike the walls of the vessel. These myriad impacts result in a pressure.
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Document ID: E01B4735

Fundamentals Of Gas Metering
Author(s): Paul m Dallapiazza
Abstract/Introduction:
This paper will provide the reader with a general overview of the fundamentals of natural gas metering. I will describe the basic operation and characteristics of the natural gas meters used in the industry today. Natural gas is a compressible fluid. This fact presents challenges to natural gas metering not found in liquid measurement. Compressible fluid volumes are greatly affected by pressure and temperature. Thus, pressure and temperature must be accounted for when measuring gas volumes. A standard cubic foot is used as a common volume reference and can be defined as gas at a temperature of 60F and pressure of 0.25 psig. Metering pressures different than the 0.25 psig standard can be adjusted by multiplying meter index reads by a calculated pressure factor or through an instrument that senses the pressure and applies the appropriate correction. Temperature is accounted for either by the meter itself or again through an instrument that measures the temperature and applied the correction. All natural gas meters can be categorized as either a positive displacement or an inferential meter
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Document ID: 52772F5F

Fundamentals Of Gas Turbine Meters
Author(s): John A. Gorham
Abstract/Introduction:
The majority of all gas measurement used in the world today is performed by two basic types of meters, positive displacement and inferential. Positive displacement meters, consisting mainly of diaphragm and rotary style devices, generally account for lower volume measurement. Orifice, ultrasonic and turbine meters are the three main inferential class meters used for large volume measurement today. Turbines are typically considered to be a repeatable device used for accurate measurement over large and varying pressures and flow rates. They are found in a wide array of elevated pressure applications ranging from atmospheric conditions to 1440 psig. Turbine meters have also become established as master or reference meters used in secondary calibration systems such as transfer provers. A significant number of both mechanical and electrical outputs and configurations have become available over the past 50 years of production
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Document ID: 5A2F2C1A

Theory Of Differential Testing
Author(s): Dave Kinsky
Abstract/Introduction:
A Differential Rate Test is an accurate and convenient method of comparing a meters performance to previous or original performance records. It is widely recognized that many State Utility Commissions or other regulator agencies accept it as a means of periodically substantiating that the original accuracy of a meter has remained unchanged. A change in internal resistance can affect the accuracy of a rotary meter. Any significant increase on the meters internal resistance to flow will increase the pressure drop between the inlet and outlet of the meter. The differential pressure appears as a prime indicator of meter condition and the test results may be used as a decision-making matrix for maintenance requirements. Resistance (increase in pressure loss) across the meter is affected by changes in flow rate, pressure, specific gravity, and internal friction. This is a good indicator to use in determining your need to pull a meter from service, or better yet a preventive maintenance program. Most meters can be flushed with an approved safety solvent, returned to service, and the differential will be close to the original data. If it exceeds specified criteria, normally a 50% increase from the baseline, the meter may require repair. The differential rate test is not an accuracy test. It does provide an excellent basis for assessing meter condition and making an educated decision as to whether the meter accuracy may be out of the users accuracy specifications.
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Document ID: B053904E

What Happens At The Flow Lab And What You Should Be Doing When You Get The Meter Back
Author(s): James Witte
Abstract/Introduction:
As linear meter development has progressed for high pressure natural gas applications the requirement for flow calibration of these meters has also increased. By far the majority of the flow calibrations are ultrasonic meters or turbine meters. This paper will offer guidance to industry personnel based on the authors experience with flow calibrations and installed meter performance monitoring.
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Document ID: 08EC1EFB

Gas Meter Proving
Author(s): Gregory A. Germ
Abstract/Introduction:
To determine the accuracy of a natural gas meter, a known volume of air is passed through the meter, and the meter registration is compared against this known volume. The known volume of air originates from the meter prover. In earlier times, the gas meter prover was a stand-alone device (usually a bell-type prover), manually operated without any electronics or automation. Today, the majority of gas meter provers are fully automated computer controlled and operated, and responsible for other job functions besides the proving of gas meters. The bell-type meter prover - though still commonly used in the industry - is not the only kind of meter prover used today. The advancements and developments in electronics and computer technology has lead to an evolution of meter proving equipment - far from the manual proving methods that were commonplace only a few decades ago. Many utilities have replaced the bell-type prover with sonic nozzle and transfer provers. Provers can now store and retrieve information from a utilitys meter management system, reduce the human error factor in the proving operation, and provide self-diagnostics to assist the prover operator in maintenance and in troubleshooting problems.
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Document ID: 64ACAB52

Electronic Volume Correctors
Author(s): Lynn Parten
Abstract/Introduction:
essential tool of gas measurement companies. The main function of the volume corrector is to calculate corrected volume of natural gas through gas meters. The corrector is used to compensate for changes in actual operating conditions of the gas system. This document will cover all aspects of these operating conditions, how they are calculated, then configured into the electronic volume corrector. There are multiple factors that are incorporated into an equation for corrected volume.
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Document ID: A44FA21A

Ultrasonic Meter Installation & Design Considerations
Author(s): James Y. Lee
Abstract/Introduction:
The custody transfer gas flow measurement applications using ultrasonic meters in United States has passed decade. The basic theory behind using ultrasonic meter (USM) is when high frequency pulse (between 100 KHz to 300 KHz) signals are sent and received between pair of transducers and measures transit time of the signal. When the signal is sent in the direction of the gas flow, the transit time will be faster than when the signal is sent against the direction of the gas flow. This difference in transit time (in order of micro seconds and nano seconds) is measured and translate into gas velocity of gas in the pipe. The uncorrected volume can be calculated using the velocity of the gas and cross sectional area of the meter.
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Document ID: 7AD98586

Installation Effect Testing On Large Ultrasonic Flowmeters
Author(s): William R. Johansen
Abstract/Introduction:
Ultrasonic flowmeters are rarely used in piping configurations that are identical to the piping configurations in which they were calibrated. What effect does this difference have on the accuracy of the ultrasonic flowmeters measurement accuracy? Ideally, all ultrasonic flowmeters would be calibrated in the piping configuration in which they will be used. Few calibration laboratories can perform calibrations in unusual or lengthy piping configurations. The next best approach is to have a calibration laboratory perform tests with a variety of flow meters, flow conditioners, and piping configurations to determine the magnitude of measurement errors produced by piping configurations.
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Document ID: 9EA98E4F

Advanced Ultrasonic Meter Diagnostics
Author(s): John Lansing
Abstract/Introduction:
This paper discusses both basic and advanced diagnostic features of gas ultrasonic meters (USM), and how capabilities built into todays electronics can identify problems that often may not have been identified in the past. It primarily discusses fiscal-quality, multi-path USMs and does not cover issues that may be different with non-fiscal meters. Although USMs basically work the same, the diagnostics for each manufacturer does vary. All brands provide basic features as discussed in AGA 9 Ref 1. However, some provide advanced features that can be used to help identify issues such as blocked flow conditioners and gas compositional errors. This paper is based upon the Westinghouse configuration (also knows as a chordal design) and the information presented here may or may not be applicable to other manufacturers.
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Document ID: E35B3117

Clamp-On Ultrasonic Meter Applications
Author(s): William E. Frasier
Abstract/Introduction:
I have applied the Siemens clamp-on meter in many configurations in the field and will describe purposes and findings on the way to precise meter certainty. The clamp-on system provides an effective new tool for insight into the flowing regime within a pipe.
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Document ID: 772FCB8C

Updates On The AGA, API, And Gpa Natural Gas Measurement Standards
Author(s): Edgar B. Bowles, Jr.
Abstract/Introduction:
This update provides the latest status of the most commonly used natural gas measurement standards and recommended practices produced by the American Gas Association (AGA), the American Petroleum Institute (API), and the Gas Processors Association (GPA). Changes in recently-revised documents are reviewed in some detail. Expected changes in documents currently under revision are also discussed, along with estimated timelines for the completion of the revised documents.
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Document ID: EE64383B

Fundamental Principles Of Pressure Regulators
Author(s): Kevin Shaw
Abstract/Introduction:
The following paper will concentrate on the fundamentals and principles of natural gas pressure regulators. In the gas regulators conception it was mainly a device used to reduce high pressure to a more usable lower pressure. Today, more is expected from the performance of the pressure regulator. Pressure reduction is no longer the only function needed. The regulator is considered an integral measurement instrument that must adhere to the stringent codes put forth by the U.S. Federal Department of Transportation and many state Public Utility Commissions. In order to understand the principles of pres
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Document ID: D8FC4BBD

Introduction To Regulator And Relief Sizing
Author(s): Jeff Sexton
Abstract/Introduction:
Sizing regulators and relief valves properly in a gas system is a fundamental yet critical step to providing safe, reliable service to customers, and achieving a long service life from the regulation equipment installed. This paper will discuss fundamental sizing and cover some of the different considerations when choosing different types of regulators. Once a base is established for pressure regulating fundamentals, this will be used as a base to discuss relief sizing criteria and application
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Document ID: CAAF17CB

Introduction To Over Pressure Protection
Author(s): Richard Fujita
Abstract/Introduction:
As far as we know, the first over pressure protection equipment used for natural gas, was a pressure relief device. It consisted of a pressurized pipe faced down into a pool (pot) of liquid (water, oil or mercury). On an over pressure, the gas would displace the liquid seal over the end of the pipe and bubble to the atmosphere. The gas industry has progressed since the use of liquid seal devices. We will discuss the various types of over pressure protection that is currently utilized by gas companies worldwide.
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Document ID: 071CE115

Flexible Element Regulators
Author(s): Ken Mears
Abstract/Introduction:
Regulators that utilize a single rubber element that performs the same function as both valve and actuator are known as flexible element regulators. The first type of flexible element regulator was developed and manufactured by the Grove Regulator Company in the 1950s. The Grove Flexflo was referred to as an expansible-tube type because a tube or rubber sleeve was stretched over a slotted metal core separating the inlet and outlet of the regulator. The tube expanded when flow passed through the regulator.
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Document ID: 92B93A84

Regulator Freeze Protection
Author(s): Jerry Nagy
Abstract/Introduction:
Freezing regulators and ice build up on pipes and regulator bodies in balmy CaliforniaNaaaah! But yes, regulators freeze off and ice builds up on pipes and the location does not matter. Freezing gas has been a problem ever since we started gas transmission and it all comes down to the transfer and distribution of energy. From 1852 to 1856 James Prescott Joule and William Thompson (who later to became Lord Kelvin), studied the phenomena of a cooling effect of an expanding gas and related it to the transfer of energy and the work done to compress the gas and the transfer of that energy (work) when the gas expands as the pressure drops. In simple terms compression equals heat - expansion equals cooling - energy balance. The temperature drop is about one degree F for every 15 psi (103 kpa) pressure drop. It is relevant to know the cooling effect
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Document ID: F8AAC1D2

Regulator Station Design
Author(s): Kevin Raschkow
Abstract/Introduction:
Regulator stations are fundamentally critical elements of any natural gas piping system infrastructure. Their primary function is to safely reduce and control gas pressure from a highpressure system to a lower pressure system within prescribed limits. The proper design of regulator stations requires a mixture knowledge, experience, judgment, science and art. It should be noted that every company is different and each regulator station is installed in distinct locations under varying circumstances and operating conditions therefore, there is not one ultimate station design station that fits all applications
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Document ID: 0D070B01

Three Mode Controller Tuning And Loop Design
Author(s): Mel Olson
Abstract/Introduction:
[Abstract Not Available]
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Document ID: F81D93ED

Troubleshooting Regulators And Control Valves
Author(s): William L. Hobson
Abstract/Introduction:
This paper will address gas pressure reducing regulator installations and the issue of erratic control of the downstream pressure. A gas pressure reducing regulators job is to manipulate flow in order to control pressure. When the downstream pressure is not properly controlled, the term unstable control is applied. Figure 1 is a list of other terms used for various forms of downstream pressure instability. This paper will not address the mathematical methods of describing the automatic control system of the pressure reducing station, but will deal with more of the components and their effect on the system stability.
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Document ID: 5D4B659B

Industrial Pressure Control
Author(s): Jim Green
Abstract/Introduction:
Regulator station designs for pressure control to large industrial loads have always presented unique challenges that differ from standard pipeline pressure control applications. A large industrial load with little buffering between the regulators and burner tips requires a different approach to station design. The design approach becomes even more complicated if the large industrial load also has additional small auxiliary requirements such as duct burners, waste heat recovery boilers, or building heat requirements. In this paper, the focus will be on a regulator station design for the newer Advanced Combined Cycle Combustion Turbine (CT) Power Plants that meet the load requirements for power plant operation as well as the load requirements for ancillary equipment
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Document ID: 93612B8E

Gas Regulation And Overpressure Protection On Other Continents
Author(s): Gianfranco De Feo Pietro Fiorentini
Abstract/Introduction:
The most common regulations outside North America dealing with pressure regulating stations for transmission and distribution of fuel gases are those established by CEN1 for the Member States of the European Union. The most important part of these regulations establishes the protection requirements against the hazards which may occur in these stations during their technical life by imposing to all concerned parties (manufacturers and users) to choose appropriate solutions in a such way to cover all hazards and, when requested, to avoid any interruption in supplying of fuel gas to the users.
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Document ID: 84F50E35

Comprehensive Examination Of Proper Gas Sampling Methods & Impact Of API 14.1
Author(s): Kris Kimmel
Abstract/Introduction:
Since a gas sampling system can be referred to as a cash register it is very important that the correct sampling method be selected and the appropriate industry standard be followed. Methods reviewed by this paper will include spot sampling, composite sampling, and on-line chromatography. In addition, Gas Processors Association (GPA) 2166-86 and American Petroleum Institute (API) 14.1 will be described. Natural gas is sampled to determine quality for custody transfer applications, balance a plant process, or gathering system. In the late 1970s most natural gas custody transfer contracts used gas volume (MCF) for the units of measure. In 1978 Congress passed the Natural Gas Policy Act in an attempt to deregulate the natural gas industry.
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Document ID: 92C103E5

Pulsation Mitigation And Its Effects On Metering
Author(s): Robert Mckee
Abstract/Introduction:
Accurate flow measurement is essential for todays gas metering, however pulsations, which are frequently present at field sites, adversely affect flow meters and are one of the factors that must be mitigated in order to achieve accurate flow measurement. Pulsation is any periodic variation in pressure and flow velocity either at one location in a pipe or from point to point along the pipe. This paper not only discusses the sources of pulsation and briefly shows how pulsation adversely affects flow meters, but also explains in detail applicable methods for mitigation of pulsation effects. Properly designed acoustic filters are the most effective means for eliminating pulsation and a design method for a simple acoustic filter is presented. Other methods to control the sources, reduce the effects, or attenuate the amplitude of pulsation are also discussed.
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Document ID: C6CC6806

Application Of Coriolis Meters For Gas Measurement
Author(s): Karl Stappert
Abstract/Introduction:
Since the early 1980s, Coriolis meters have gained worldwide acceptance in gas, liquid, and slurry applications with an installed base of more than 500,000 units. Through significant design enhancements in the early 1990s Coriolis meters have rapidly gained worldwide acceptance in gas phase applications with over 35,000 meters installed world wide and most notably the 2003 publication of AGA Report Number 11, Measurement of Natural Gas by Coriolis Meter.
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Document ID: 0B765DB6

Turbine Gas Meter Calibration By Alternative Fluids
Author(s): Paul W. Tang
Abstract/Introduction:
Accurate calibration of turbine meters is increasingly attracting attention from natural gas companies due to the recent high gas commodity cost. The most common medium used for calibrating gas turbine meters is natural gas. Using natural gas as a calibration medium offers the closest match of physical properties for turbine meters used in the natural gas industry. However, it is often difficult and costly for natural gas based meter calibration facilities to operate over a wide pressure and temperature range due to the restrictions in their physical configurations. The relationship between Reynolds number and the performance of a turbine meter is a well established fact. A turbine meter is primarily a rotating machine which responds to the Reynolds number of the flow. The AGA No.7 Report 1 stipulates that the Kfactor of a turbine meter determined by matching
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Document ID: 34016299

Onsite Proving Of Gas Turbines
Author(s): Daniel J. Rudroff
Abstract/Introduction:
With the increased use of Natural Gas as a fuel, and higher natural gas prices buyers and sellers of natural gas are seriously looking at ways to improve their natural gas measurement and reduce the error in natural gas measurement. An error in measurement of only one tenth of one percent (0.1%) on 100 Million Standard Cubic Feet (MMSCF) of Natural Gas selling at 7.00 per Thousand Standard Cubic Feet (MSCF) will cause an over or under billing of 700.00. A 6 Turbine or Ultrasonic meter operating at 1,000 Psi will move 100 MMSCF/Day. Therefore the error in a year is (700 X 365) 255,500.00 This will more than pay for a proving system
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Document ID: 5A8AF9AB

Effects Of Flow Conditioning On Gas Measurement
Author(s): Dr. Darin L. George Edgar B. Bowles, Jr.
Abstract/Introduction:
There are many causes for natural gas flow rate measurement errors at field meter stations. Many of the sources for meter error are identified in the proceedings of this conference. For instance, errors can result from an improper installation configuration, calibration of a meter at conditions other than the actual operating conditions, or degradation of meter performance over time. Industry standards have been developed to help meter station designers and operators avoid situations that would produce gas metering errors. Typically, gas meter standards address meter design, construction, installation, operation, and maintenance. Most of the standards focus only on the flow meter and the piping immediately upstream and downstream of the meter. Research has shown that many meter types, particularly inferential meters, are susceptible to errors when the flow field at the meter is distorted. The sources of flow field distortions are many. The piping geometry upstream of a flow meter can create flow distortions that may propagate several hundred pipe diameters downstream before completely dissipating. Sudden changes in the pipe diameter either upstream or downstream of a meter may also introduce flow field distortion. Branch flows, such as those produced by meter station headers, control valves, regulators, and other flow restrictions or expansions, can also create distortions in the flow.
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Document ID: E9A7132E

Cathodic Protection And M&R
Author(s): Dale Schultz
Abstract/Introduction:
Although goals and objectives of the measurement and regulation (M&R) personnel and those of the corrosion control group may be very different, what they do individually may affect the overall success of the associate group. This paper is intended to give M&R engineers and technicians a basic understanding of corrosion control including the challenges and hazards associated with CP (cathodic protection). With this knowledge I hope to stimulate the questions necessary for M&R and Corrosion Control departments to work together for better system integrity, reliability and safety.
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Document ID: B9D60263


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