Unaccounted-For Gas
Author(s): Mike Haydell
Abstract/Introduction:
Unaccounted-for gas figures can be either positive (more gas purchased than sold) or negative (more gas sold than purchased). In either case, it is important to determine what factors are contributing to the unaccounted-for gas and eliminate them. We are concerned about unaccounted for gas for two reasons safety and economics. Concern about unaccoimted-for gas for public safety include: leakage, third party damage and gas theft. These factors contribute to unaccounted-for gas that can adversely affect the safety of our customers. Economically, unaccoimted-for gas represents lost revenues that are not recoverable. It is gas purchased from a supplier but not sold to customers (positive unaccounted-for gas).
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Document ID:
6F6BCFEF
Communication Between Orifice And Field
Author(s): Duane A. Harris
Abstract/Introduction:
Todays gas industry is constantly changing, with increasing demands on office and field personnel. To meet these demands requires timely communication between the office and field employees. Both of these locations (field and office) have been impacted with increased work loads and constant upgrades in equipment and software. With all of this happening, it is very easy to overlook one of the key links to accurate measurement and that is communication. By the time that a gas day has started on a chart or RTU until the volume has been calculated or verified, anywhere from 1 to 50 days can pass with as many as 8 to 10 people handling each individual chart. With this many people involved covering that span of time, communication becomes a vital part of the measurement process.
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Document ID:
0EBA64D4
Field Sampling
Author(s): Doyle N. Hathaway
Abstract/Introduction:
Sampling of natural gas has changed greatly in recent years. This has been necessitated by the change in emphasis from volume to heating value pricing. It has caused the evolution of sampling techniques and equipment necessary to acquire representative samples. This paper will present in some detail the importance of industry standard procedures for procuring these samples.
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Document ID:
9001ACC4
Electronic Vs Mechanical Correcting Devices
Author(s): Philip Legendre
Abstract/Introduction:
Mechanical and electronic correctors both take an imcorrected output from a gas meter (line volume) and perform volume corrections based on the ideal gas laws. The result is a meter reading (corrected volume), which is used to bill the customer. Both produce the same end result but use very different methods.
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Document ID:
19264A6C
Fundamentals Of Natural Gas Chemistry
Author(s): Jerry Bernos
Abstract/Introduction:
At the thought of having to study and learn chemistry, most individuals feel that the subject is far to complex to be within the realm of their understanding. NOT SO! Just as a person does not have to be an auto mechanic to drive a car, one does not have to be a graduate chemist to learn a few basic chemical concepts. This presentation will not turn you into a trained chemist. It should, however, give you a very basic and simplified understanding of the nature of the materials that we are required to deal with on an ongoing, everday basis.
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Document ID:
BC26A8E6
Computer Applications To Chart Processing
Author(s): Dewayne Mosley
Abstract/Introduction:
How can we do it better? How can we do it faster? Can we maintain or increase our accuracy? Is it costeffective? Have you not asked or been asked these type of questions recently? The growing need for increased accuracy, speed and precision is pressing all around us. Our entire industry must constantly seek to improve if we are going to keep up! In order to achieve the quality of measurement we desire, we must learn to find and fully utilize the latest, technologically advanced tools now on the market. We have all seen the introduction of newer and better instruments for meter measurement. The office personnel have not been left out, either! Using a computer for fully automated chart processing systems can enhance the speed and accuracy at which volumes are calculated and accessed.
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Document ID:
6378DBD4
Contract Interpretation With An Eye Towards An Unbundled Environment
Author(s): John A. Hoehn
Abstract/Introduction:
I have been employed by MRT for the past seventeen years. My first nine years with the Company were spent in Gas Accounting, the last eight in Gas Supply. Currently, I am responsible for the administration of our gas purchase contracts and upstream transportation agreements (i.e., transportation by others). Over the past years I have worked closely with Gas Measurement and Gas Control. MRT is an interstate pipeline which originates in East Texas and runs east through the Ark-La-Tex producing region to Perryville, Louisiana. From PerryviUe the system runs north through Arkansas and Southeast Missouri to St. Louis, Missouri, its principal market area. Because there is very little native production connected to MRT, we purchase the majority of our supplies offsystem and ship across a number of upstream pipelines originating from the Gulf Coast, Anadarko and Arkoma basins. Currently, MRT is both a merchant and an open access transporter.
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Document ID:
AD22CF8D
Charts, Pens And Ink
Author(s): Douglas Eberhardt
Abstract/Introduction:
How did the recording chart evolve to its present state? There are many factors which contributed to the design of the circular recording chart. The charts size, shape and arc lines are varied with each instrument manufacturer. The original paper and printing inks used to produce recording charts were based on the state-ofthe- art technology. These materials varied widely from manufacturer to manufacturer. When a printing company evaluates paper, there are a multitude of factors that must be taken into account. The paper companies manufacture their products from trees, and not every tree is alike therefore, not every paper company prepares or processes their paper in the same manner with regard to furnish, opacity, finish, tear and tensile strength, ink penetration or sizing, and dimensional stability. The printing media (paper) will be dimensionally affected by humidity and temperature based on the site of usage ex. Alaska vs. Gulf Coast).
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Document ID:
8189E26B
Fundamentals Of Diaphragm Meters
Author(s): L. Alan Hess
Abstract/Introduction:
A diaphragm meter is a positive displacement instrument which measures gas volume passed through it using the physical displacement of a known amount of gas for each stroke of a diaphragm. The diaphragm also provides the separation between the measuring chambers. As such the diaphragm meter has been proven to be an accurate, reliable means of measurement through many years of service. Due to its positive displacement operation, it is especially accurate at low flow conditions.
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Document ID:
A7D3477D
Applications Of Telemetering In Gas Distribution
Author(s): Tom Cathey
Abstract/Introduction:
This piper will provide the reader with a general over view of the Methods, applications, and equipment now being utilized in monitoring and controlling gas distribution and transmission systems. Gas distribution and transmission companies have within their organization departments which are responsible for the monitoring and controlling of pressures, flow rates and volumes. These departments are commonly refered to as gas control and the individuals in these departments trm referred to as dispatchers.
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Document ID:
718030EE
Design Considerations For Orifice Meter Tubes
Author(s): Kenneth E. Embry
Abstract/Introduction:
The most widely accepted means of measurement of natural gas and other fluids is the Orifice Meter. The primary elements of the orifice meter include the orifice plate, orifice fitting or flanges, adjacent piping and flow conditioner, or straightening vanes which make up the Meter Tube. The criteria for design, manufacture and application of orifice meters has existed for many years, but with limited support data. Recent studies from the United States and Europe have proven standards for Orifice Meters to be inadequate to achieve the degree of accuracy required.
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Document ID:
69C0BB24
A Solution For Small Station Odorization
Author(s): Joe F. Arnold
Abstract/Introduction:
The concept for Gas Pulse Odorization was introduced to the Natural Gas Industry in a paper entitled Gas Pulse Odorization by H. R. Heath, MOUNTAIN FUEL SUPPLY COMPANY, Salt Lake City, Utah presented at the International School of Hydrocarbon Measurement, April 16, 1981. At this time, MOUNTAIN FUEL SUPPLY COMPANY had been designing, installing, and operating gas pulse odorizers for approximately ten years. These early units controlled volumes of natural gas saturated with odorant from a standard by-pass type odorizer through the use of a three-way cam operated pneumatic switching valve alternately packing and exhausting a volume chamber connected to the common port of the valve. The meter mounted pneumatic switch manufactured by MERCURY INSTRUMENTS, INC. is stroked by a multi-lobe cam attached to a basic gear train driven by a diaphragm meter wiggler.
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Document ID:
727E8F00
Electronic Chart Integrators
Author(s): Bryan Billeaud
Abstract/Introduction:
In the natural gas industry, measurement and calculation of gas volumes have long been accomplished through the use of orifice meter chart records. Machines which make the calculation from these records are a common sight to most companies involved in gas measurement. Electronic equipment, especially, have brought about substantial improvement to measurement and calculations due to their ever increasing speed, accuracy and mathematical abilities. There are many variables and methods used in the volume calculations generated from these chart records. One important consideration is the pressure extension. The pressure extension is derived directly from a chart record. It is computed from two independent curves on the chart which depict the pressure, in psi, found in an orifice meter tube and the differential pressure, in inches of H2O, of the opposite sides of the orifice. In accordance to the Bernoulli theorum, these two curves are considered as continuous records over a specified period of time.
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Document ID:
EF2BD147
Field Inspections And Calibrating Measurement Instruments
Author(s): George E. Brown III
Abstract/Introduction:
The following paper details methods and equipment used for checking volume recording and correcting devices that would normally be connected to positive displacement, rotary and turbine meters in lieu of a direct reading/compensating index. The scope of equipment types that are applicable to these procedures are as follows: 1. Volume and Pressure/Temperature Recording Gauges 2. Mechanical Pressure/Temperature Volume Correctors 3. Electronic Pressure/Temperature Volume Correctors 4. Electronic Flow Computers
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Document ID:
88A33D4E
Fundamentals Of Energy Determination
Author(s): Thomas E. Sowell
Abstract/Introduction:
It has long been the practice of gas companies to record custody transfer strictly on a volumetric basis. This practice began to change, however, when Congress passed the Natural Gas Policy Act of 1978. Federal intervention came as a result of large price differentials between state and federally regulated natural gas. The Act sought to restore consumer confidence and instill a sense of fairness in the gas system. One of its provisions specified that natural gas was to be bought and sold on the basis of energy content. End users were free to purchase gas on a commodity market basis and use participating pipelines as conduits to transport gas to their particular locale. The cost benefits were initially impressive - but only to some customers. It soon became apparent that gases were of varying qualities resulting in increased consumption at some sites whereas others used less. As a result, unknown qualities had an unsettling effect on the entire system.
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Document ID:
8F4A6FA3
Chart Editing And Integration Methods To Reduce Errors And Obtain Accurate Gas Volumes
Author(s): Gary P. Menzel
Abstract/Introduction:
The title assigned to DS for this presentation may imply that we can define specific means to reduce errors and thereby improve measurement accuracy. Certainly we hope that our observations may contribute to that purpose but there is something unique about each companies operations which prevents the application of a single procedural formula to everyone, and we will make no attempt to do so. However, a substantial part of our business is auditing gas purchasers, and we believe the statistics obtained in that process provide a representative cross section of the kinds of errors experienced by most chart departments. Defining a problem may be the first step toward its resolution, and it is that which we shall address in this report.
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Document ID:
F9C86EC8
Sample Conditioning Of Natural Gas
Author(s): Ken A. Hudgeons
Abstract/Introduction:
Natural gas is one of our most valuable and profitable properties. Expert handling will pay abundant dividends however, the flow profile within the confines of the pipeline is very important in determining whether a representative sample is going to be taken. If proper techniques and procedures are not followed, the condition of the sample will lead to inaccurate revenues being distributed to both the purchasers and sellers of the product. Just as the meter tube is the primary element in the gas measurement system and the recording device is the secondary element, the condition of the sample is the primary element in the analysis of Natural Gas.
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Document ID:
7C0AE9C4
Fundamentals Of Orifice Meter Recorders
Author(s): John Clark
Abstract/Introduction:
The objective of this paper is to give any reader a basic understanding of orifice meter recorders including the purpose, types and operation. In the natural gas industry, it is critical for producers, gatherers, transporters, distributors and customers to accurately account for the volume of gas they buy, sell or move. Measurement inaccuracies can result in substantial losses or gains of income. For many years, the orifice meter has been the most widely used measurement device in the natural gas industry. The orifice meter recorder is a secondary measurement device. The primary device is the orifice meter tube and connection fittings.
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Document ID:
B73C72E7
H2S Detection In Natural Gas
Author(s): Mitch Mccain
Abstract/Introduction:
NATURAL GAS TRANSMISSION GAS COMPANIES ARE SEEKING TO GAIN A COMPETITIVE EDGE BY OPERATING THEIR SYSTEMS WITH EVER INCREASING EFFICIENCY. THIS IN TURN DRIVES THEIR NEED FOR STATE OF THE ART INSTRUMENTATION. THE USE OF THE MICROPROCESSOR WITH EQUIPMENT TO MONITOR CONTAMINANTS SUCH AS HYDROGEN SULFIDE, CARBON DIOXIDE AND MOISTURE IN A USUALLY CLEAN NATURAL GAS FUEL HAS LED TO THE DEVELOPMENT OF CONTROLRELATED TECHNOLOGIES TO ASSIST IN THE TRANSMISSION OF NATURAL GAS THROUGH COMPLEX PIPELINE TRANSMISSION NETWORKS.
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Document ID:
C8775E2C
Carbon Dioxide Detection In Natural Gas Pipeline Systems
Author(s): Maurice Barnes, Jr.
Abstract/Introduction:
Carbon Dioxide (CO2) detection and monitoring capability is desirable in pipeline operations downstream of Amine treating plants or in other locations where CO2 concentrations have the potential of exceeding contract or operational specifications. The scope of this paper is to evaluate the effects of Carbon Dioxide on pipeline operations, to provide a basis for evaluating design and operating requirements of continuous CO2 monitoring instrumentation, and to examine the theory behind infrared spectroscopy analysis.
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Document ID:
8760136A
Meter Selection For Various Load Requirements
Author(s): Anthony A. Schneemann
Abstract/Introduction:
As gas prices and cost of equipment rise, the measurement of the product will increase in importance and it will be up to the measurement engineer to design the most efficient and economical meter station possible after all, the gas meter is known as the Cash Register of our business.
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Document ID:
5AEAC177
The Metering Of Pulsating Flow - One Companys Case History
Author(s): Orin Flanigan
Abstract/Introduction:
For Arkla, the problems of pulsation were first addressed in 1950 when it was discovered that there were symptoms of pulsations at its reciprocating compressor stations. Hold down straps broke, vibration was excessive, and piping failed. An investigation revealed that other transmission companies were having similar problems with their reciprocating compressor stations. In order to attack this problem, 13 gas companies and compressor vendors formed a group called the Pulsation Research Council under the administration of the Southern Gas Association. The group put up some money and retained the Southwest Research Institute in San Antonio to study the problem.
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Document ID:
D03B7A75
Fundamentals Of Orifice Metering
Author(s): Burton G. Reed
Abstract/Introduction:
The purpose of this paper is to discuss the fundamental components used in orifice measurement. The general concepts of head meters, which include the orifice, have been known for centuries. The orifice has been in commercial use since the early 1900s. The device is used to create a differential pressure which relates to the velocity of the gas from which a flow rate can be calculated. As the flowing gas passes through the restriction in the line caused by the orifice plate the difference in the upstream and downstream pressure can be measured at set points, called taps, and a flow rate at the point can be determined.
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Document ID:
75F32CE1
Chart Auditing
Author(s): Michael D. Beck
Abstract/Introduction:
The primary purpose for auditing charts is to verify the integration and volume calculation for a particular site. There are a number of additional benefits to be realized, which we will briefly illustrate. Errors in reported volumes can usually be attributed to one or more of the following reasons * Mistakes in integration interpretation. * Improperly calibrated machine. * Integrated with incorrect range setting. * Data input errors. * Missed orifice or range changes. * Incorrect meter tube ID used. * Improper or missed averaging during times of recorder malfunctions, freezing, etc. * Unaccounted for hours of flow. * Misinterpretation and/or missed flow around zero line. * Missed gravity or BTU updates. * Unaccounted for recorder errors, found and corrected at inspection. * Incorrect pressure base used. * Temperature averaged incorrectly. * AGA recommended factors not all utilized. * AGA procedures not used. As you can readily see, reporting
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Document ID:
3488A93B
Fundamentals Of Self Averaging Pitot Tubes
Author(s): Darreli Pebley
Abstract/Introduction:
Just because a flow measurement device is complex and/or expensive does not automatically mean that it is the best or most accurate. Oftentimes the most simple device is just as good and accurate and frequently even better. Economic pressure encourages the emergence of better all-around devices with greater reliability and accuracy. These and other factors have brought to the fluid flow measurement industry the Multiport Averaging Primary Row Measurement Device. This refined version of the basic pitot tube, the same as the orifice and other headtype primaries, is based on the same standard hydraulic equation, continuity equation and Bernoullis Theorem. Thus, an extension and improvement of proven concepts and device makes available to the industry a primary flow measurement device which offers many benefits. including a simple design, with equal or better performance for fluid flow measurement and process control applications.
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Document ID:
7CA1BF17
Natural Gas Sweetening With Alkanolamines
Author(s): Rick Baldwin
Abstract/Introduction:
Natural gas as produced from the wellhead contains several undesirable components. Hydrogen Sulfide (H2S) and carbon dioxide (CO2) are two of the more commonly encountered impurities found in a typical wellhead natural gas stream. Hydrogen sulfide and carbon dioxide are called acid gases because they form weak acids when combined with water. Hydrogen sulfide is a toxic gas which must be removed from natural gas before it can be used as a commercial fuel. The following table lists the toxic effects of hydrogen sulfide:
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Document ID:
DBFAC620
Using Electronic Optical Chart Processors
Author(s): John Barber
Abstract/Introduction:
With electronics and computers having taken over our business and personal lives by storm over the past 10 - 15 years, the very way that chart recordings are calculated could not be excluded from this ever present advancement. That is why Cascade Natural developed what we feel is the most efficient accurately repeatable chart reader on the market today. By combining a solid state camera and fiber optics this new chart reader can read up to three pen charts by distinguishing the color of the pen recordings with their function. And with the unique design and applicable software we are able to read orifice and displacement charts with nominal diameters of 8, 10 and 23 inches. But, what was I to say that hasnt been said before? That was my problem.
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Document ID:
E36B604A
Meter Shop Equipment And Operations
Author(s): Jon T. Payne
Abstract/Introduction:
The meter test and repair function is an essential element of the gas distribution industry. The role of the meter shop in the typical distribution company has undergone revision, driven primarily by changing economic and technological factors. For most of the 1980s, rising labor costs and low efficiencies compelled many distribution organizations to curtail meter repair operations. One school of thought viewed Ihe residential gas meter as evolving into a disposable item. As new technology and modern automation techniques have been applied to the meter shop, this trend has been reversed in recent years. A renewed interest in meter lest and repair operations has resulted in modernization of several meter shop facilities across the country. The concept of a comprehensive meter test and repair facility appears to be resurgent among many organizations.
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Document ID:
9D4B047F
Principles Of Odorization
Author(s): Edwin H. Roberson
Abstract/Introduction:
The detection of natural gas leakage has long been a concern to the natural gas industry, but never more so than today. Increased public awareness of safety and huge increases in the cost of product liability litigation has resulted in a greater focus on gas odorization. While it is recognized that odorization will not be 100% effective in warning of the presence of natural gas, a basic understanding of the odorants and some of the potential problems in odorization can help in achieving the highest possible results.
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Document ID:
2909E39E
Minimizing The Effects Of Pulsation Induced Gage Line Error
Author(s): David L. Winkler
Abstract/Introduction:
Pulsations created by compressors, flow control valves, regulators, and some piping configurations are known to cause significant errors in gas flow measurement. In recent years the Pipeline and Compressor Research Council (PCRC), a subsidiary of the Southern Gas Association, commissioned and funded various pulsation research projects at Southwest Research Institute (SWRl) in San Antonio, Texas. This research culminated in the publication of several technical papers, including the April 1987 PCRC report 10.87-3 titled Pulsation and Transient-Induced Errors at Orifice Meter Installations and the most recent technical report An Assessment of Technology for Correcting Pulsation Induced Orifice Flow Measurement dated November, 1991. Though originally produced for PCRC members only, these reports are now available to the industry for a nominal charge.
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Document ID:
2D7AB913
Spot Sampling Techniques
Author(s): Jerry Bernos
Abstract/Introduction:
In 1978 the United States Congress passed the Natural Gas Policy Act. This legislation required that natural gas be priced according to its energy content rather than by volume alone. At the same time, the economics of the natural gas industry caused natural gas prices to soar. These two factors resulted in a vast increase in the demand for accurate analyses of natural gas systems. Since it was not economically feasible to place analytical instruments at each and every location requiring BTU determinations, a corresponding Increase occurred in the need to obtain spot samples of these systems. This paper is intended to present the problems that arise in spot sampling and to introduce the industry accepted methods which can overcome these problems.
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Document ID:
0EBFD27D
Overall Measurement Accuracy
Author(s): T. Dean Graves
Abstract/Introduction:
To fully understand measurement accuracy, it is first necessary to look at the measurement process from a business stand point. All business transactions, such as purchases, sales, transportation, exchanges, compression, and treating fees are based upon the gas volumes recorded during a predetermined time period. Company departments cannot complete their functions until volumes are reported. It is critical to the business process that these volumes be as accurate as possible. Many people have been striving for years to refine the measurement process to make it as accurate as possible. Unfortunately, there are still limitations to measurement accuracy. This paper will attempt to examine some of these limitations.
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Document ID:
68C5A9F7
From Pen Tip To Volume Statement
Author(s): Philip C. Morris
Abstract/Introduction:
Accurate and reliable gas measurement depends on a combination of efforts and investments. In large companies these efforts include the legal department for contracts, the engineering department for specifying equipment and the purchasing department for buying that equipment. The field service department must then install the equipment. By the time the meter pen tip records the first gas production, there will have been literally dozens of people involved, from land men and geologists to drilling and production people. Regardless of company size there is always a major investment of time and money before the actual measurement process begins. It is the measurement departments job to deliver the results of all of the hard work and money invested.
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Document ID:
94AB1EC2
Operational Procedures Of Electronic Chart Processor
Author(s): Chuck Gray
Abstract/Introduction:
The UGC Chart Processor is a microprocessor based system designed to translate orifice meter chart records into accurate billing-compatible data of integrated flow (chart extension), flow time and average pressure. It will handle American (Westcott) and Foxboro charts as the pens can be mounted so as to pivot in the same geometric paths as the recording pens of these types of meters. As an option, the Chart Processor can be fitted with pen mounts for Taylor and/or Rockwell charts. The operator directs the pens to follow the records by moving the trace handles as the chart rotates. The rotational speed of the chart table is governed by a variable foot control. The chart is secured to the chart table so Its rotation and the motion of the pens by the operator simulate the actions in the recording meter.
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Document ID:
0E6B5FAE
Field Testing Of Hihg Volume Gas Turbine Meters
Author(s): Jim Beeson
Abstract/Introduction:
This paper examines a patented mobile gas turbine meter proving system that blends technology from liquid turbine meter provers with innovative ideas that particularly apply to gas measurement. Arkla Pipeline Group developed and currently uses this mobile sonic nozzle prover on gas turbine meters ranging in size from 3 thru 16 at meter station sites under actual operating conditions. The prover also incorporates a gas chromatograph which is used in the actual mass flow computations. This system has numerous enhancements over former methods of proving gas turbine meters. Arkla formerly proved its larger turbine meters, having capacities of 60,000 ACFH (Actual Cubic Feet per Hour), with a Roots transfer prover capable of only 10,000 ACFH. This meant that the provings were at or near locations on the proving curve where the K-factor (Pulses per Actual Cubic Foot) might be in error for the turbine meters normal flow rate. With the prover Arkla can now prove a turbine meter at the rate it is actual1y flowing.
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Document ID:
DC45451F
Fundamentals Of Turbine Meters
Author(s): Robert Bennett
Abstract/Introduction:
Gas measurement in the U.S. and around the world is dominated by diaphragm, rotary, turbine, and orifice meters. Each serves a different segment of the gas industry and each has its own set of advantages and disadvantages. These four main types of meters can be broken into two distinct categories: positive displacement, and inferential.
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Document ID:
0BDC34C9
A Portable/Stationary Gas Chromatograph Used For Heating Value Measurement
Author(s): Jeff Moon
Abstract/Introduction:
The production and custody transfer of natural gas requires accurate measurement of the composition of the gas. Contractual requirements usually define the desired composition, heating value, relative density, and moisture content of the gas being sold. The sale of natural gas is performed on the basis of the heating value per unit volume (kj/m3 or Btu/Scf) of the gas. For these reasons, the industry has used instruments to monitor the characteristics of the gas at the point of sale. The following instruments are commonly found in the field and in the laboratory: Gas Chromatographs Gravitometers Moisture Analyzers Densitometers Hydrogen Sulfide Monitors Oxygen Monitors
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Document ID:
AA217A3F
Gri Metering Research Facility Update
Author(s): John G. Gregor
Abstract/Introduction:
The status of the Gas Research Institutes Metering Research Facility Program at Southwest Research Institute is reviewed. This significant project was initiated in 1987 to establish an independent flow calibration facility, operated under the sponsorship of the U.S. natural gas industry, for supporting priority flow measurement research, development, and testing needs. Facility capabilities and development progress are summarized along with the ongoing GRI-sponsored research activities.
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Document ID:
4BE1C4C0
Testing Odorant Concentration: Various Methods Of Testing For Proper Odorant Levels
Author(s): Edwin H. Roberson
Abstract/Introduction:
Odorant monitoring is a complex subject. Odorant concentration test instruments have been in use for approximately fifty years and many users are satisfied with their reliability. There are others, however, who feel that the test results of these instruments are meaningless. Since both sides in this disagreement are using the same type of instrument, the problem appears to surround the manner in which the odor level test is taught and run. There are as many ways to make an odorant concentration evaluation as there are gas companies. Although research has been conducted to determine the effect of odorant on the olfactory sense, no large scale scientific study has used odor level test instruments. In other words, no research, beyond that conducted by individual gas companies, has determined the proper way to use these instruments. NevKiheless, many gas companies are convinced that these instruments make gas systems safer.
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Document ID:
D65CBCCC
High Pressure Measuring And Regulating Station
Author(s): J. Bryan Butler
Abstract/Introduction:
High pressure measuring and regulating stations are an important part of every pipeline system. Their primary function is to provide safe and dependable high pressure measurement and regulation of natural gas transported from one pipeline to another. High pressure measuring and regulating stations are located along pipeline systems at sales and purchase points such as: O Pipeline interconnects O Industrial sites O Power plants O City gates O Production sites
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Document ID:
6318D538
Pulsation Induced Errors In Flow Measurement
Author(s): Henry W. Poellnitz
Abstract/Introduction:
The natural gas transmission industry has historically placed a strong dependence on the orifice meter as the standard for custody transfer measurement. The simplicity, reliability, low maintenance, rangeabtlity, and repeatability of the orifice meter along with the development of reliable secondary systems has eliminated attempts to displace the orifice meter where accurate flow measurement is required. Accuracy of the orifice meter has been a subject of considerable discussion in the last ten years. Recent experimental work to refine and extend the data base for orifice coefficients generally indicates an uncertainty of about *A % under carefully controlled and measured laboratory conditions. Field accuracies of generally 1 % are often quoted. Unfortunately, field errors arising as a result of nonideal fiow conditions are often an order of magnitude larger than those experienced under precise laboratory conditions.
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Document ID:
E23A27B9
Determination Of Specific Gravity By Various Methods
Author(s): E. D. Woomer, Jr.
Abstract/Introduction:
This paper deals with the determination of specific gravity via various methods and pieces of equipment. Also covered are definitions, relationships, and effects of specific gravity. The information presented herewith is applicable to United Gas Pipe Line Co, and conforms to accepted standards of the natural gas transmission industry.
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Document ID:
4D84E154
Water Vapor Determination And Effects On Gas Measurement
Author(s): Douglas E. Dodds
Abstract/Introduction:
The determination and the effect of water vapor on gas measurement is of Importance to the gas pipeline industry because of the necessity for accurate gas measurement and for the maintenance of quality control. The following discussion covers typical methods which are used by the gas industry for water vapor determination. Each of the dew point instruments discussed use a specific method for water vapor measurement, and all are designed for use as either portable or fixed location instrumentation. In addition to a discussion of the typical methods for water vapor determination, the effects of water vapor on gas volume and heating value measurement is reviewed.
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Document ID:
06A76A87
Fundamentals Of Pressure Regulation
Author(s): William L. Hobson
Abstract/Introduction:
For all practical purposes, regulators used by the gas industry can be placed in either of two categories: I. Self-Operaled II. Pilot-Operated This categorizing of all regulators (plus all construction modifications) tends to be an over-simplification, but exceptions are rare. Lets examine each of them closely.
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Document ID:
DE39A631
API 14.3/AGA3 Mechanical Specifications Old - Vs - New
Author(s): Steven P. Klak
Abstract/Introduction:
In February of 1991, API and AGA issued a revised orifice meter standard that significantly changed many of the mechanical requirements of orifice meters. The revised standard is referred to as API 14.3 Part 2 or AGA 3 Part 2. In the two years since its release the standard has gained wide acceptance and with good reason - adherence to the new requirements promises improved measurement accuracy. The new document is technically sound. The old standard was based on old, limited data. The new standard is based on a great amount of recent test data. The new standard is much clearer with regards to what is exactly required. Because of this, the interpretation and understanding is much easier. Most of the changes involved reducing the tolerances allowed within the orifice meter, clarifying old requirements and adding a few new ones. The purpose of this paper is to present the new requirements, discuss practical interpretations, and offer possible inspection methods.
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Document ID:
F25BA596
Fundamentals Of Rotary Metering
Author(s): Robert Bennett
Abstract/Introduction:
Gas measurement in the U.S. and around the world is dominated by diaphragm, rotary, turbine, and orifice meters. Each serves a different segment of the gas industry and each has its own set of advantages and disadvantages. These four main types of meters can be broken into two distinct categories: positive displacement and inferential. Diaphragm and rotary meters fall into the positive displacement category because they have welldefined measurement compartments that alternately fill and empty as the meter rotates. By knowing the volume displaced in each meter revolution and by applying the proper gear ratio, the meter will read directly in cubic feet or cubic meters. Turbine and orifice meters on the other hand have no measurement compartments to trap and then release the gas. These meters are categorized as inferential meters in that the volume passed through them is inferred by some physical characteristic being observed or measured.
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Document ID:
C954BA43
Field Testing By Transfer Proving
Author(s): Carlos T. Ponce
Abstract/Introduction:
There currently exists three types of field proving equipment for testing large diaphragm, rotary and turbine meters. The three types are low pressure, critical flow and transfer provers. Both low pressure and transfer proving are generally performed with air and at a vacuum (or in the case of low pressure proving optionally at a slight positive pressure) white critical flow proving is done with gas at 15 #s plus. For transfer proving, the prover is located on ihe outlet side of the meter being tested, as it is for critical flow proving. However, it may be located upstream or downstream for low pressure proving. Similarly when low pressure proving the blower can be on the inlet or outlet (but always on the opposite end from the prover). The blower location for transfer proving is not only downstream of the meter but also downstream of the prover. In critical flow proving a blower is not necessary.
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Document ID:
0940C704
Electronic Flow Meter Auditing
Author(s): Gary R. Menzel
Abstract/Introduction:
As Electronic Flow Meters (EFM ) replace the more traditional chart recorders as the method of recording and calculating custody transfer volumes in the natural gas industry, it becomes more and more important to be able to audit the volumes produced by these devices Our company has been doing some audits on electronic flow meters since 1984 and currently audit over 25 different pipelines at EFM custody transfer stations. Over the twelve month period ending December, 1992, we found errors on over 3% of all of these stations audited which were resolved by agreement between the parties involved. The incidence of error on the EFM stations we audit falls in the same range as that of the chart recorder stations audited. We have summarized the types of errors we have found in EFM auditing and these results are listed in table one. Where a category is listed as .00%, it is an error which has occurred in the past but that did not occur in during the twenty four month period included in the table. Where possible, we have kept the same code numbers as we use to classify errors found in chart auditing, though in fact the location where many of these occur has moved from the office to the field.
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Document ID:
93C71A8B
Operations Of On-Line Chromatography
Author(s): Louis N. Cox
Abstract/Introduction:
Gas Chromatographs used in Energy Measurement and Control Systems are designed for minimum amount of maintenance. With the Introduction of Microprocessors, Advanced Electronics and Self Diagnostics, the reliability of measurement devices has increased considerably. As new devices are introduced, chromatograph manufacturers incorporate these devices into their system to increase reliability and reduce maintenance. A typical Chromatograph for BTU measurement is illustrated in Figure 1. In order to properly maintain and troubleshoot a chromatograph, you must have complete manufacture documentation, wiring diagrams and a digital volt-OHMmilliammeter along with normal hand tools. If you are not familiar with repairing printed circuit boards, rely on the manufacturer to repair these boards.
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Document ID:
08FD4817
Basic Electronics For Field Measurement
Author(s): Arnold Del Toro
Abstract/Introduction:
Electronics in Orifice Measurement has only recently become more prevalent for on-site use. When gas was inexpensive the need for accurate measurement was not there. Historically, mechanical circular charts have filled the need to record flows, pressures and temperatures. But today we in the gas measurement business have seen an ever increasing demand to know what the true volume is at the site. With this demand comes electronics in the form of transducers and flow computers. The purpose of this paper is to make you- the field measurement operator- more aware of electronics and how it relates to our future field measurement systems. Over the past few years it has been more practical to use electronic systems to duplicate the control effects that can be produced with pneumatics. With the refinement of solid state electronics to the commonly know Integrated Circuit (IC) came the advantage of lower cost and higher reliability. In addition to the lower cost and higher reliability, the electronics has the advantage of almost instant transmission of signals to remote locations, and the signal is easily adapted to a variety of control systems. Customers of these systems have realized a quick payback of lower operational costs and real time data.
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Document ID:
2258EB2D
Measurement Of Energy Content In A Gas
Author(s): Ashu K. Gupta, Bill Bonett
Abstract/Introduction:
In the natural gas industry, the monitoring of energy content has increasingly become of paramount importance. During custody transfer and for billing purposes, accurate, reliable, and continuous monitoring of the energy content of the gas is a necessity. This measurement may be obtained from two different types of instruments: Ones that measure the energy content directly, and others that do it indirectly. Calorimeters measure this value directly whereas Gas Chromatographs (GO measure it indirectly. The oldest and most trusted Calorimeter has been the Cutler- Hammer Calorimeter. Changing requirements and needs have permitted other techniques to come to the forefront. These new calorimeters provide faster measurement of the BTU/SCF of the incoming gas. Chief among these are the following: The Therm-Titrator, the FLO-CAL Calorimeter, and the Cosa Calorimeter. The GC is the only significant instrument in the indirect measurement arena.
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Document ID:
90A7EC39
Influence Of The Latest Revision Of Ansi 2530 (AGA U3) On Flow Computer Software
Author(s): Raymond G. Teyssandier
Abstract/Introduction:
The new American Petroleum Institute. American Gas Association. Gas Processors Association orifice metermg standard represents the first major change in the USA calculation procedures published since 1935. As almost all of the approximately 19 trillion cubic feet of natural gas in the USA passes through orifice meters this standard will have a significant impact. This new standard will result in not only different, but also more accurate, volumes then those calculated by all previous USA or international standards. The changes that were made to reach these improvements were all based on the latest availuU)le data that had been gathered by vanous USA and European researchers. The new orifice measurement standard is written in four parts, separating the text to facilitate use and simplify updating when changes are needed. The sections are: Part 1-General Equations and Uncertainty Guidelines Part 2-Specifications and Installation Requirements Part 3-Natural Gas Fluid Measurement Part 4-Implementation
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Document ID:
DE69418E
Periodic Inspection Of District Regulators & Relief Valves
Author(s): George L. Bell
Abstract/Introduction:
Inspections of district regulating stations and overpressure protection devices are essential in complying with Federal and State Regulations, District regulators reduce high inlet pressure to a lower outlet pressure that is below the maximum allowable operating pressure (M.A.O.P.) for a segment of pipeline. The district regulators may also be used to reduce an intermediate pressure to an even lower utilization pressure. District regulators may be installed for your companys operation to reduce a line segments lost and unaccountable, gas purchased, tapping requirements, or odorization problems. Overpressure protection devices are devices that protect the downstream pipeline in the event of a regulator failure. These devices include the relief valve, the monitor, and the pressure shutoff. These regulators and overpressure protection devices, because of their importance to system operations, must be inspected in accordance to federal and state regulations.
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Document ID:
4A8D353A
Pulsation Effect On Gas Turbine Meter Measurement
Author(s): Equimeter, Inc.
Abstract/Introduction:
In a number of gas flow measurement applications (e.g., gas production fields, compressor stations, pulsation induced by regulators), the flow may not be steady, but pulsating. Pulsating flow may cause error in flow measurement by a turbine meter. Frequently, this can be rectified by placing the meter further from the source or by adding a pulsation dairpener, but sometimes this is not possible. Thus, it may be inportant to knew whether the magnitude of the error due to pulsating flow condition is significant.
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Document ID:
7DB3E0EF
Handling Hazardous Wastes
Author(s): John Sommer
Abstract/Introduction:
As natural gas is produced, processed, and transported to market, various wastes are generated that must be handled in accordance with applicable Federal and State regulations. The purpose of this paper is to provide measurement technicians involved with day to day operations of pipeline facilities some basic guidelines to identify and handle the following wastes: 1. Used Mercury 2. Mercury Contaminated Soil 3. Filters - Oil, gas and glycol 4. Spent Solvents 5. Produced Water 6. Used Glycol 7. Used Lube Oil 8. Hydrocarbon Contaminated Soil 9. Tank Bottoms 10. Off-Specification Condensate 11. Pigging Wastes
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Document ID:
0609E127