Measurement Library

American School of Gas Measurement Technology Publications (1996)

American School of Gas Measurement Technologies

Pulsation Effects On Orifice Metering Considering Primary And Secondary Elements
Author(s): Roben J. Mckce
Abstract/Introduction:
The use of orifices for commercial flow measurement has a long history dating back more than 50 years. Orifices are extensively used in the United States natural gas, petroleum, and petrochemical industries and are important as one of the most practical ways to meter large volumes of gas flow. These meters are very reliable and cost effective and if properly used, can be relied upon to give accurate results. Proper use normally requires the steady flows for which orifices were, intended and for which the orifice coefficients were developed. In actual field installations, flow is often not steady but subject to the periodic changes in pressure and velocity that are referred to as pulsations. Pulsations can be caused by compressors, pressure regulators, control valves, fluctuating loads, or by flow-induced phenomena within the piping. It is known and well recognized that pulsations cause errors in orifice meter results. In fact, A.G.A. Report No. 3 on Orifice Metering of Natural Gas, which is also ANSI/API 2530, clearly states that: Reliable measurements of a gas flow with an orifice cannot be obtained when appreciable pulsations . . . are present at the measurement point.
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Document ID: F10B1AB4

Networked Gas Measurement Systems
Author(s): Steve Ogorman
Abstract/Introduction:
There are many design considerations associated with the developme:nt of systems that can measure gas flow and transfer the data to a central location. A systems perspective is required when considering the use of electronic gas measurement to satisfy the business and operational challenges that are present in todays gas industry. It is essential to understand the fiinctions of individual components and how they will become integrated into a complete, networked system. Financial tools are often used to evaluate different component selections. As well, a proposed analysis can be utilized by designers to approximate the uncertainty associated with any measurement system.
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Document ID: AFCF2524

Choosing The Complete Gas Measurement System
Author(s): Richard L. Cline
Abstract/Introduction:
Since the discovery of oil and gas and the advent of commercial conveniences which use oil and gas, ccmpanies have been confronted with the need to accurately measure the oil and gas bought and sold in the marketplace, And, as usual, the technology available at the time was bought to bear on the measurement process.
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Document ID: 0D6F138E

Communication Between Office And Field
Author(s): Duane A. Harris
Abstract/Introduction:
The gas industry today is constantly changing, with increasing demands on office and field personnel. Initially there was FERC Order 636 that forced the gas measurement departments into the electronic age. Next came corporate slashing that has required the gas measurement groups to perform at the same level of integrity in measurement with reductions in staff of up to 60%. 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 occurring, it is very easy to overlook one of the key links to accurate measurement and that is communication.
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Document ID: D2389BD2

Conract Compliance How Todays Contracts Meet Customer And Government Requirements
Author(s): Patricia Anderson
Abstract/Introduction:
The nature of gas contracts have changed dramatically with FERC Order 636. Over the last several years, pipelines generally continued to dominate the long-term, firm sales market because of their ability to provide service on a no-notice, peaking basis. Order No. 636 eliminates this advantage by both forcing pipelines to provide such service through the same transportation arrangements used by other suppliers, and providing these alternative suppliers with a broader array of tools to meet the firm peak needs of users. Gas consumers cormected to interstate pipelines enjoyed the best of both worlds. FERC regulations required pipelines to stand reaify to meet the full needs of those customers on virtually no notice, but did not require the customer to enter into any type of reciprocal commitment.
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Document ID: 14169705

Fundamentals Of Orifice Metering
Author(s): Kenneth E. Embry
Abstract/Introduction:
Throughout the oil and gas industry, there stems the need for accurate, economical measurement of process fluids. Orifice metering satisfies most flow measurement applications and is the most common flow meter in use today. The orifice meter, sometimes called the head loss flow meter, is chosen most frequently because of its long history of use in many applications. versatility, and low cost, as compared to other flow meters available.
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Document ID: 9408908C

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: D15B9B3D

Periodic Inspections Of District Regulator & Relief Valves
Author(s): Jerry Bowins
Abstract/Introduction:
Inspections of District Regulator Stations and over pressure protection devices are essential in complying with Federal and State regulations. In order to understand the functions of a District Regulator Station a overview of the pipelines system is necessary. Pipeline companies bring the gas from the well head and into a gathering system. A Gathering system is the system which a pipeline uses to transport gas from a current well site to a transmission line or main. From the gathering system, it goes to a station where the pipeline may do several functions which may include compression, dehydration, processing and regulation. At this point the pressure is lower or equal to the MAOP of the pipeline system. The gas leaves this station at the pipelines operating pressure. This gas goes through the pipeline to the City Gate Station, where the pipeline lowers their pressure below the maximum allowable operating pressure (MAOP) of the line inside the City Gate Station.
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Document ID: 6AD8DC61

Electronic Equipment Classifications In Hazardous Locations
Author(s): Brad R. Erickstad
Abstract/Introduction:
The use of electrical equipment in hazardous locations is not new and weve witnessed the safe use of electricity such industrial locations for many decades. However, growth in the use of electronic equipment in natural gas hazardous locations has grown dramatically over the last ten years. Semiconductor and microprocessor technologies are driving more and more electrical and electronic devices out of the shop and office and into areas which may have significant concentrations of natural gas. Common sense tells us that a mixture of natural gas in air combined with electricity is not a safe combination. Nevalheless, the question is asked: Can such a marriage work and be safe? The answer: Certainly. Is it difficult for the average end-user to determine the suitability of such a marriage? No, not necessarily, but like a real-life marriage, a lot of questions need to be asked before making any commitments. Hazardous locations, as maniages involve legal questions some people prefer to ignore and, of course, others have differences of opinions. New and unfamiliar technologies are being used in hazardous locations and this is causing confusion for new-comers. Misapplication of some technologies has raised safety concerns. Our purpose in this paper is to provide an overview of the issues and very briejfy discuss some of the technologies used in overcoming safety related problems in hazardous locations. Unfortunately, the field is too broad to go into detail.
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Document ID: E57DE73B

A.G.A. Report No. 8 And Its Effect
Author(s): Kenneth E. Starling
Abstract/Introduction:
The natural gas industry is currently implementing extensive changes in orifice flow calculations for natural gases. The technical basis for these calculations is provided by the results of cooperative worldwide research carried out in recent years. The technical documentation for die calculation methods appears in the most recent versions (1992) of American Gas Association (A.G.A.) Report No. 3, Orifice Metering of Natural Gas and Other Related Hydrocarbon Fluids and No. 8, Compressibility Factors of Natiual Gas and Odier Related Hydrocarbon Gases, and Chapter 14 of the American Petroleum Institute (API) Manual of Petroleum Measurement Standards. It should be noted that Section 2 of Chapter 14 of API MPMS is equivalent to A.G.A. Report No. 8 (Reference I).
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Document ID: A846B1FB

Economics Of Electronic Measurement
Author(s): Harry J. Workmen
Abstract/Introduction:
During the last 10 years, gas measurement has gone through a period of incredible change. Since the early 1900s, mechanical recorders have dominated the gas measurement industry but, since 1985, the advent of low powered flow computers has been changing the way we do business in the gas industry. There are over 50,000 flow computers in daily operation in the United states from a variety of manufacturers. This fundamental change in a basic process has produced impacts on the economics of the gas industry in several areas.
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Document ID: 5848F6BA

Field Sampling
Author(s): Doyle N. Hathaway
Abstract/Introduction:
Sampling of natund gas has changed greatly in recit 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 equipmrat necessary to acquire rrestative samples. This paper will presoit in some detail the importance of industry standard procedures for procuring these samples.
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Document ID: FD8EB960

Transfer Provers
Author(s): John D. Gray
Abstract/Introduction:
A Transfer Prover consists of a master meter mechanically set to zero percent error. It is equipped to read temperature, pressure and correcting for any difference between the master and field meter. Transfer Prover 12185 was my first prover. It came to me in 1975. Technology has moved rapidly in the gas industry with provers DOW being run by laptop computers. This enables field technicians to pre-configure and save to the menu any meters and their desired flow rates. The latest provers warn of high differential, low test times, questions as to your purging meter of gas after blocking meter in, and taking pressure off the meter. If your transducers sense any pressure, it is programmed not to allow the test nm to start. This safety feature shoidd make you attend to any gas leaking by the valves that have the meter isolated from flow of gas to customers.
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Document ID: 271143B5

Effect Of The Latest Revision Of Ansi 2530(AGA #3) On The Primary Orifice Metering Element
Author(s): Douglas Watkins
Abstract/Introduction:
Significant improvements in the equations which govern the measurement of natural gas using orifice meters, have necessitated changes in the primary devices used to gather the data. These changes have been incorporated into the new revision of the API 14.3 Part 2 Third Edition (AGA-3, ANSI 2530) and are detailed in the following discussion. 1. Eccentricity of the bore of the orifice plate to the bore of the fitting. 2. The distance from the face of the orifice plate to the sealing face of the orifice fitting. (Recess and Protrusion) 3. Pipe roughness and internal diameter tolerances. The error in the coefficient of discharge has been reduced by approximately one half when orifice meters(fittings, flanges, etc) conforming to the new revision of the standard are used. These new orifice meters are constructed to much tighter dimensional and configurational requirements than in the past. Orifice meters which do not meet the requirements of Part 2, must have an in-place calibration run to determine the coefficient of discharge curve over the range of Reynolds Number expected.
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Document ID: A81AC35F

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 dejiartment 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 UteraUy 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: 07996D6B

Techniques Of Natural Gas Sampling
Author(s): Kris Kimmel
Abstract/Introduction:
In recent years, the measurement of natural gas has experienced tremendous change. The acceptance of electronic flow measurement, as a common practice, has no doubt changed the method and time required to measure gas in custody transfer and allocation applications. With changes in industry standards, and technology, we will see more advancement in this area in the future. Another closely related area of measurement, which has experienced change in recent years, involves the sampling for quality of natural gas. These changes include developments in instrumentation, and a new sensitivity to the importance of proper sampling techniques to insure the integrity of the sample before analysis. The concern in the accuracy of the sample, naturally, may involve the monetary considerations of custody transfer, the balancing of a gas gathering system, or even the control of a process within a plant. But always, it is the composition of the sampled gas, acquired in such a manner, deemed representative, and then related to flow that is important.
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Document ID: 30BCBDFB

Orifice Meter Test Procedures For Chart Recorders
Author(s): Curtis R. Fillman
Abstract/Introduction:
Orifice meter measurement with a chart recorder has been a standard in the petroleum industry for years. The orifice meter consists of the plate and tube (primary element), and the recorder (secondary element). It has been popular for years because the meter is a simple device which requires minimal maintenance and can accurately measure a wide range of flow rates. Orifice meter measurements can affect sales, reservoir engineering, production allocation, gas allowables, royalties, and, ultimately, your paycheck. Therefore, it is important that the meter be routinely tested to ensure sustained accuracy. The frequency of the meter test is dictated by company policy, contract, or whrai the meter is thought to be in error. Most companies test their meters monthly or quarterly, depending upon the volume of gas measured.
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Document ID: AEA44988

Problems Unique To Offshore Measurement
Author(s): James G. Young
Abstract/Introduction:
Most of us have arrived at this meeting in some kind of company provided transportation. This is supplied in order for us to do our assigned jobs. These may be trucks, cars, helicopters or even boats. For those who are involved in the offshore industry we know that transportation involves the greatest expense. The helicopter expense for our company is close to the 9 million dollar range. Since this cost is so high, we are constantly looking at ways to reduce it.
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Document ID: 1E578439

Traceability Of Test Instruments Selection, Applications, And Use.
Author(s): Gregg m. Kloeppel
Abstract/Introduction:
How good is the measurement you are making and is the measurement as good as the measurement you made yesterday, a week ago, or even a year ago. We will review the selection of test instruments and why an instruments accuracy, repeatability, operating temperature and traceability is important to the ultimate goal of a good measurement. Next we will look at the measurement process and what relevant factors influence the collection of data for measurement assurance. Finally, we will review both National and International Standards for maintaining instrument traceabi lity and the requirements for maintaining documented traceability.
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Document ID: 1C9DB352

Minimizing Gage Line Distortion Through Manifolds
Author(s): Dave Bell
Abstract/Introduction:
The natural gas industry has been using orifice meters for custody transfer since the early 1900s. Not until the late 1980s has the orifice regained its reliability. It really never lost its dominance only some people thought that other types of meters would do the job easier and with greater accuracy. Through the introduction of the electronic transmitter and the electronic flow computer the problems with pulsations were exposed to all modes of measurement. Through establishment of the Pipeline Compressor Research Council by the Southern Gas Association and in conjunction with the Southwest Research Institute, San Antonio, Texas, years of data gathering in the lab and in the field found the orifice was not the root to all evil in custody transfer. All this data is now public domain for public use. This paper will show how the manifolds of present design has helped to minimize problems in measurement accuracy and in some installations completely solved gage line distortions.
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Document ID: 29B17F3C

Meter Change-Out And Routine Testing Programs
Author(s): Don Yarbrough
Abstract/Introduction:
With the understanding that the gas meter is the cash register, it is important that the accuracy of that meter is maintained. This sets up the need for routine inspection. Routine inspection will be determined based upon the number of various types of meters a company may have, Any company will need to take the following conditions into account: 1 . Number of meters 2. Type of meters 3. Test Intervals 4. Company labor expenses 5. Contract labor expenses These conditions along with historical test data will allow each company to develop the testing procedures best suited for their company.
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Document ID: 54C5D022

Fundamentals Of Orifice Recorders
Author(s): Paul Toomey
Abstract/Introduction:
This paper will cover the fundamentals of an orifice recorder. The American Gas Association defines the orifice meter as the complete measuring unit consisting of a primary and secondary elements. The meter tube and orifice plate with connection fittings are considered the primary measuring device. The meter or recorder is the secondary device. The meter tube along with the orifice plate is considered the metering device...the recorder or meter, records the events that are created in the meter tube.
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Document ID: 27918854

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: 23372312

Gri METF.RING Research Facility Update
Author(s): John G. Gregor, Edgar B. Bowles, Jr.
Abstract/Introduction:
The Gas Research Institute (GRI) sponsors a comprehensive flow measurement research, development, and commercialization (RD&C) program aimed at improving metering performance in the field. This paper summarizes some a major accomplishment of the research program, establishment of the GRI Metering Research Facility (MRF), a high-accuracy natural gas flow calibration laboratory capable of simulating a wide range of operating conditions for the industrys research, calibration, and testing needs. The MRF, located at Southwest Research Institute (SwRI), supports a variety of GRI-sponsored research and third party test/calibration activities. GRI MRF Program research includes projects on: orifice, turbine, and ultrasonic meters, gas sampling, and distribution measurement. Through a portfolio of projects addressing priority research needs, the GRI measurement program provides significant benefits to the natural gas industry.
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Document ID: 32BA9199

Handling Hazardous Materials Related To Measurement
Author(s): Lanny W. Cargile
Abstract/Introduction:
Anyone involved with natural gas measurement has surely had occasions when handling hazardous material was necessary. Knowing how to properly handle these materials has not always been an easy task. Here we will look at some of the regulations and other guidelines that address the handling of hazardous materials and where to obtain information on handling specific hazardous materials.
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Document ID: 8087B7F6

Fundamentals Of Self Averaging Pitot Tubes
Author(s): John Perry
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. Often 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 Flow Measurement Device. The refined version of the basic pitot tube, the same as the orifice and other head-type primaries, is based on the same standard hydraulic equation, continuity equation, and Bernoullis theorem. Thus, an extension and improvement of proven concepts and devices makes available to the industry a primary flow measurement device that 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: B2A1D192

Fundamentals Of Gas Laws
Author(s): John Chisholm
Abstract/Introduction:
In the gas industry a standard unit of measure is required, In the English system it is the standard cubic foot. In the metric, ii is the standard cubic meter. This standard unit is the basis of all exchange in the gas industy. When the unit of purchase is the energy content (BTU) we achieve it by multiplying the BTU content of a standard cubic foot times the number of cubic feet delivered to the customer. So we must obtain standard cubic feet or meters. A standard cubic foot is defined as one cubic foot of gas at a pressure and temperature agreed upon by the buyer and seller, Coirmion standard conditions are 14.73 psia and 60 Fahrenheit, The gas passmg Ihrough a meter is rarely at standard conditions. It is necessary to convert the gas in the meter from the metered conditions to standard cubic feet. The tools we have for relating volume to pressure and temperature are Equations of Stale or, simply, the Gas Laws.
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Document ID: 61C13E54

Overall Measurement Accuracy
Author(s): L.K. Bryant
Abstract/Introduction:
Websters Ninth New Collegiate Dictionary defines accuracy as: 1: Freedom from mistake or error: correctness 2a: conformity to truth or to a standard or mode: exactness b: degree of conformity of a measure to a standard as a true value. Accuracy is an interesting word in the gas industry and particularly in the world of gas measurement. The quest we all seek to obtain is the perfect cubic foot. To seek that perfect cubic foot of natural gas we must begin with a standard. A standard is something accepted as the norm or model for the industry, as a starting point, The standard for the gas industry in orifice measurement is the AGA Report No. 3 and No. 8. In positive and displacement measurement it is the AGA Report No. 7.
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Document ID: 693321E5

Field Experience With Electronic Calibrators
Author(s): Claude A. Winslow
Abstract/Introduction:
The use of electronic pressure calibrators in the gas industry has added new concerns and issues in pressure measurement. With the onset of electronics, new and strange words began appearing. Readings appeared that perhaps didnt match the old reliable standby calibration methods. Terms like sensitivity, accuracy, resolution, traceable standards, and correction factors gave the technicians a challenge when performing their calibrations. One can add to this already complicated list, the effects that temperature has on the test instrument and how that effects the accuracy of gas measurement.
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Document ID: D4E9543C

Operation Of Orifice Meter Chart Integrator
Author(s): Gary Hammond
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 cable 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. The Chart Procesor computes and prints (for each chart) the chart extension ( JTrT), average pressure and flow time. It also stores and prints batch totals on command.
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Document ID: DBC02044

Fundamentals Of Natural Gas Chemistry
Author(s): Douglas E. Dodds
Abstract/Introduction:
It is believed that the word gas was derived from the Greek word chaos. This is probably a true statement since gas molecules exists in a permanent state of chaotic motion. A gas, unlike solids and liquids, is matter that has no internal boundaries. As a result, gas molecules are in continuous motion and expanding to completely fill any confining space. To truly understand gas measurement, a person must understand the fundamentals of natural gas chemistry.
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Document ID: 41127FC9

Techniques Of Natural Gas Sampling
Author(s): Thomas F. Welker
Abstract/Introduction:
There is no other way to receive proper payment for the natural gas that we purchase, transport, produce, process, or sell except by accurately determining its heating value, specific gravity, and compositional analysis. Regardless of whether the determination is made by using an on-line analyzer, gas sampler, or sending a person to collect a spot sample, the accuracy of the analysis is determined by the quality of the sample. The first factor that must be covered is the person chosen to physically take the spot sample, or install and maintain the sampling device. This person is the beginning of a successful sampling program. The final outcome of the sample operation will be determined by the efforts of this first link in an unbreakable chain of operations that must be performed without variances which can and will affect the outcome of the results obtained.
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Document ID: 241BE90F

Training In The Volume Processing Office
Author(s): Judy T. Pawlik
Abstract/Introduction:
When someone begins a new and exciting career in measurement, they are truly about to embark on an incredible journey!! They couldnt possibly have any idea whats in store for them!! You could throw them out there to sink or swim - but then again it could be your company doing the sinking carrying you and your fellow employees with it. If the company is to be successful, then it must have a successful Measurement Department. For this reason, trainers are needed to train the new hires, or perhaps to train an experienced employee in a new task.
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Document ID: 48726E7C

D.O.T. Mandated Training
Author(s): Jim Gorman
Abstract/Introduction:
Training is nothing new to our industry. It has been around for as long as Gas has been sold commercially. So why all the concern over mandated training? Probably fear of the unknown is our highest hurdle too clear. Currently, D.O.T. Mandated Training is only proposed and not in print. Yet reliable sources still say its only a matter of time before the Rule making is made.
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Document ID: 554306D7

Computer Applications In Chart Processing
Author(s): Russel W. Treat, Sharon Stinson
Abstract/Introduction:
The natural gas business has been undergoing an incredible amount of change in recent yeare, and the gas measurement department has not been exempt Significant changes in regulation and market dynamics continues to drive much of this change. At the same time, newer, less expensive, more flexible and more powerful computer systems are enabling companies to adapt and make necessary changes. As the cost of computing continue to fall, and as systems offer more perfonnance and flexibility, we can expect that the only constant will be constant change.
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Document ID: CE9324DD

Chart Auditing
Author(s): Angelia Parish
Abstract/Introduction:
Chart auditing is of equal value to original measurement work. The monetary value of potentiai volume and BTU adjustments justify the existence of an audit group or the addition of audit function. A measurement department that delivers only original measurement misses the opportunity to increase the contribution it makes to the company served using existing skills and equipment. However, measurement skills represent only one of the ingredients necessary for a successful chart audit function. The components other than measurement skills constitute the subject I will pursue. Because the department for which I work is an example of the application of many of these components, it will serve as the model for this presentation. Elements covered are: * The reliable access to information concerning possible metering points to audit so that audit can begin even before initial delivery. The routine comparison of original volumes to corresponding outside company volumes made after monthly close so that potential adjustments can be isolated and pursued. These comparisons also reduce unnecessary chart auditing. A reliable system to track audit charts and statements received for audit, and the careful handling of these charts while in office. Methods practiced routinely to isolate the causes of measurement discrepancies.
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Document ID: 25A4B3C9

Fundamentals Of Egm - Electrical Installations
Author(s): Michael D. Price
Abstract/Introduction:
The areas of gas measurement and communications have seen substantial changes in the last few years as the natural gas industry adapts to effects of the economy, low gas prices, warm winters and government deregulation. Every company has studied, debated, hired consultants, and finally determined how gas flow data is to be measured and collected. AH gas companies have hundreds and even thousands of points which must be accurately measured. Data is retrieved from very remote and rugged locations. Climate conditions can range from humid off-shore platforms to deseit conditions with both temperature extremes included. No commercial power is available, allowed or even desired at these locations making the solar-powered electronic gas measurement equipment the ideal method of gathering flow data.
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Document ID: C648FEBD

Electronic Transmitters
Author(s): Jim Griffeth
Abstract/Introduction:
What is a TRANSDUCER? What is a TRANSMITTER? What is the difference between transducer and a transmitter? What is the absolute, and transducers? difference between Gauge, differential pressure Why is one transducer more, accurate than another? How does a. transducer & transmitter work? How often should one calibrate a transducer or transmitter? Over the course of this paper we will answer the above questions in enough detail as to satisfy most field technicians.
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Document ID: 63534413

Lightning Protection And Grounding For Remote Flow Computers
Author(s): Clifford R. Pelchat
Abstract/Introduction:
The purpose of this paper is to discuss the methods that can be used to protect electronic equipment from electrical surges caused by lightning. Probably everyone reading this article can share an experience where damage to some electronic device was caused by lightning. Lightning can strike utility structures a great distance from a meter installation and still cause major damage to the electronic instrumentation. These strikes can cause surges on telephone lines, AC electrical lines, and sometimes, buried steel pipe lines. At times these surges can reach several thousand volts. Protection is generally achieved by diversion and shielding or by limiting the amounts of currents and voltages that can pass through the equipment. I will discuss a typical installation and the steps that you can take to provide proper grounding, (diversion), and some of the methods and devices that are used to limit current and voltage.
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Document ID: 05C103AE

C6 - Electronic Vs. Mechanical Correcting Devices Two( Approaches For Volume Corrections On P.D. And Turbine Meters
Author(s): Warren m. La Mar
Abstract/Introduction:
Today we are here to discuss the electronic volume corrector versus the mechanical volume corrector. First a small bit of history, as you can see from this chart, (Figure 1) in the mid 1920s the meter mounted chart recorder came into existence. Around 1930, the mechanical volume corrector or volume correcting index came into being. These mechanical correctors used several methods of applying pressure and temperature correcting factors, based on Boyles Law for pressure and Charles Law for temperature, to the uncorrected metered volume.
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Document ID: 9A8723F7

Fundamentals Of Rotary Metering
Author(s): Todd A. Reeves
Abstract/Introduction:
The first positive displacement rotary gas meters were built in 1920 by the PH S FM ROOTS Company and the Connersville Blower Company, both located in Connersville, Indiana. In 1966, this gas meter operation was renamed Dresser Measurement Division. However, these rotary meters today are still known as ROOTS Meters. Rockwell International entered the market in the early 1960s with a rotating vane design known as the ROTO-Seal* Meter, and in the late 1960s Singers American Meter Company introduced still another rotating design known as the CVM gas meter. There are several foreign competitors who also manufacture a lobed rotary meter.
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Document ID: 62928481

Meter Selection For Various Load Requirements
Author(s): Mike Haydell
Abstract/Introduction:
Gas meters have become known as the CASH REGISTER of the natural gas industry. With todays competitive energy markets and the environment of FERC order 636, natural gas measurement has become an increasingly important issue. It is therefore the duty of measurement departments, to select equipment and design installations that are both efficient and economical.
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Document ID: 25EB3914

Pulsation Reduction By Acoustic Filters For Metering Applications
Author(s): Larry E. Blodgett, Robert J. Mckee
Abstract/Introduction:
Because of the adverse effects of pulsations on orifice and other types of flow meters there is for many installations, a need to eliminate or decrease the amplitude of pulsations in the piping. This task has been the primary domain of acoustical piping designers who have had both theoretical and practical field experience in such areas. the most common and effective treatment for pulsation control is the design and installation of acoustic filters. However, most filters designed by novices are not effective and are costly to operate because of pressure drop losses. This paper discusses the basic principles and considerations in acoustic filter design.
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Document ID: 0B3FE5BE

Applications Of Telehetering In Gas Distribution
Author(s): Ton Cathey
Abstract/Introduction:
This paper will provida the reader with general over view of the methods, applications, and equipment now being utilized in monitoring and controlling gas distribution and transmission systems.
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Document ID: B5B0BC6E

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 unaccounted-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, unaccounted-for gas represents lost revenues that are not recoverable. It is gas purchased from a supplier but not sold to customers (positive imaccounted-for gas).
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Document ID: 60D25076

Egm Data Editor Requirements
Author(s): Michael Squyres
Abstract/Introduction:
The natural gas industrys adoption of EGM as a means of increasing the speed and accuracy with which measurement information is obtained, has created the need for an electronic data management system. These systems, if not properly designed and implemented, could potentially render the entire process useless. Therefore, it is essential that the system add functionality that complements the power of the hardware. With proper implementation, such a system will not only facilitate operations in todays fast paced, post-FERC 636 environment, but also will establish a foundation for meeting tomorrows measurement challenges.
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Document ID: 4157B6DB

Electronic Flow Meter Auditing
Author(s): Gary P. Menzel
Abstract/Introduction:
As Electronic Gas Meters (EGM ) 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 30 different pipelines at EGM 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 EGM stations we audit falls in the same range as that of the chart records stations audited.
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Document ID: 4CEA669B

Using Cellular Digitized Packet Data Cdpd() In A Scada System
Author(s): Dean Gordonwood
Abstract/Introduction:
In 1992, nine cellular service providers came together to form a consortium, the purpose of which was to develop a specification of a standard for the transmission of digital data packets over the cellular network. The companies forming this consortium are: Ameritech Mobile Communications, Inc. Bell Atlantic Mobile Systems Inc. GTE, Mobilnet Inc. Contel Cellular, Inc. McCaw Cellular Communications, Inc. NYNEX Mobile Communications, PacTel Cellular, Southwestern Bell Mobile Systems. These companies came together to address the need their customers had to send small messages over the cellular system at a reasonable cost. In July 1993, the first release of the specification for Cellular Digital Packet Data (CDFD) was issued. By the end of the third quarter of 1995, CDPD had been deployed in 49 Metropolitan Service Areas around the United States. As the deployment of CDFD continues, using it as a means of communication in a real-time SCADA. system is becoming a viable alternative to current methods of data communication. This paper will describe what CDFD is, how a CDPD system works in general, the components of a CDFD network, its use in an installed SCADA application and the advantages and disadvantages of CDPD as opposed to other technologies.
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Document ID: 2B335BC1

Fundamentals Of Energy Determination
Author(s): Thomas E. Sowell
Abstract/Introduction:
This paper presents fundamental information necessary to understand and appreciate the concept of total gas energy in a natural gas pipeline. That is, to be able to converse with peers within the natural gas industry and understand basic concepts and terminology. Discussed is the historical transition from volumetric measurement to total gas energy including some of the basic terminology, physics, measurement as well as the reasons for changes in methodologies. Included is the industries acceptance of new concepts and regulations involving custody transfer as well as the instrumentation and systems involved in traditional and newer, more progressive forms of gas measurement.
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Document ID: 5D18F847

Training Gas Measurement Personnel
Author(s): A. S. Buddy() Harris, Jr.
Abstract/Introduction:
Todays technology in the field of gas measurement is constantly changing, and the training of its measurement technicians is of the utmost importance. These technicians must be continually educated in order to possess the most current knowledge of the latest equipment on the market today. Also, it is essential that this type of instruction should be taught in a controlled environment where the technicians can learn and develop the necessary skills with the least amount of interruptions from external sources.
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Document ID: DB58661E

A New Perspective On Measurement
Author(s): Lohit Datta-Barua, Ph.D.
Abstract/Introduction:
We have all heard various slogans and words about measurement such as Measurement is (he cash register, Measurement is a necessary evil, Measurement is an inexact science, etc., and there may be some truth in them. Unfortunately, the measurement persons perspective of measurement has not changed much with time. We recognize that new technology and a new business environment have complicated our lives, but the overall view has been very narrowly and technically focused. We talk about the technical defensibility of what we do without taking responsibility for its economic impact. We revise technical documents, and we get carried away with the best accuracy at any cost. We apply the latest and greatest supercompressibility calculations to six decimal places to calculate a few MCF of gas which flow through an oversized meter run that has not been checked in a long time. The bottom line is: We cant see the forest for the trees.
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Document ID: F567843D

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 : displacement, and Diaphragm and rotary into the positive group because they defined measurement that alternately fill the meter rotates volume displaced positive inferential. meters fall d i sp1acement have wellcompartments and empty as By knowing the in each meter revolution and by applying the proper gear ratio, the meter will read directly in cubic feet or cubic meters.
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Document ID: 1C2108BB

Field Testing Of High Pressure Gas Turbine Meters
Author(s): Maurice Barnes, Jr.
Abstract/Introduction:
The accuracy of a field meter station in natural gas operations should be verified directly under actual operating conditions by a master meter or prover. In recent years, new provers have been developed for operation at high line pressure and flow rates. This paper evaluates turbine meter dynamics, effects of gas composition on prover accuracy, and two prover technologies available for field proving of high pressure gas turbine meters.
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Document ID: 7FF2DCD0

Influence Of The Latest Revision Of Ansi 2530 (AGA #3) On Flow Computer Software
Author(s): Raymond G. Teyssandier, Ronald E. Beaty
Abstract/Introduction:
The new American Petroleum Institute, American Gas Association, Gas Processors Association orifice metering 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 US passes through orifice meters this standard will have a significant impact. This new standard will result in a not only in 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 available data that had been gathered by various US and European researchers. The new orifice measurement standard is written in four parts to separate 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: D6877233

Fundamental Principles Of Diaphragm Meters
Author(s): Eric D. Thompson
Abstract/Introduction:
A diaphragm meter is a positive displacement instrument which is used to measure the volume of gas that passes through it. This is accomplished through the known volume that is displaced for each stroke of the diaphragm. The diaphragm also provides the seal between the measuring chambers of the device. As such the diaphragm meter has proven to be an accurate and reliable means of measurement of gas for many years. This is especially true at low flow rates because of its positive displacement characteristics. This paper includes a brief history of diaphragm meters, an explanation of the operation of the diaphragm meter, a basic review of the function and design of the positive displacement meter, discusses meter ratings and capacity, and introduces temperature compensation.
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Document ID: 2339A7D9

Low Power Flow Computers
Author(s): Rick Heuer, Charles Derr
Abstract/Introduction:
As we enter the second decade of use of LOW POWER FLOW COMPUTERS, (LPFCs), we do so with significantly different hardware, software, economics and motivating forces. These differences are worthy of close examination as they ultimately will affect all of us in this industry. In order to focus on the majority of applications for LPFCs, we will limit this discussion to those operating on battery only or batteries with recharging systems. We will particularly focus on the stand-alone flow computing RTUs and their measurement and control functions. Remote communication, data gathering, data concentration, editing, automatic billing and remote gas system control are of such importance in this era of low gas prices as to be a virtual requirement for staying efficient enough to be competitive. These considerations significantly effect the selection criteria of LPFC hardware, software, telemetry and gas control schemes.
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Document ID: 412902E7

Design Of High Pressure Metering And Regulation Stations
Author(s): Jimmie L. Butler
Abstract/Introduction:
What is high pressure? Any pressure greats than utilization or, as most companies define utilization pressure, 6 inches water column? Does your company consider 10 psig to be high pressure? 100 psig? 1000 psig? As the old saying goes, everything is relative. Therefore, each company must decide internally what it considers to be high pressure. Later discussion will touch on topics generally associated by industry with high pressure meter and regulator stations.
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Document ID: 52EB7C7A

Fundamentals Of Pressure Regulation
Author(s): Bill Hobson
Abstract/Introduction:
Gas pressure regulators have become very familiar items over the years, and nearly everyone has grown accustomed to seeing them in factories, public buildings, by the roadside, and even in their own homes. As is frequently the case with many such familiar items, we all have a tendency to take them for granted. Its only when a problem develops or when we are selecting a regulator for a new application that we need to look more deeply into the fundamentals of the regulators operation.
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Document ID: 3EA88850

Process For Blending Components
Author(s): Joe Queck
Abstract/Introduction:
The preparation and proper use of gas and liquid standards has become very sophisticated in the last decade. Advances in both manufacturing and analytical methodology have greatly increased the reliability and diversity of both gaseous and liquid standards. A whole industry has evolved from the demand for these mixtures. Gas and liquid standards have similar consideration prior to manufacture. The first consideration should always be: Can the mixture be made? To determine the feasibility of preparing a standard, one must consider the possible limitations, either physically or safety imposed. Physical limitations may include things such as purity, vapor pressure restrictions, and reactivity. Safety considerations include filling density, reactivity, and selection of the proper container, valve, and safety devices in accordance with D.O-T (Department of Transportation) Regulations and recommendations of the Compressed Gas Association.
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Document ID: 8E9F7333

PORTABLE/MOBILE Gas Chromatography
Author(s): Glenn Praesel
Abstract/Introduction:
With natural gas being bought and sold in units of energy, and not in units of volume as in the past energy determination has become paramount. Although there are different ways to determine the energy value of nahural gas the most widely used method is gas chromatography. This ia for many different reasons, but the main reasons are accuracy, repeatabilty, and functionality of the data. However, another important advantage of this method is that it can be made portable/mobile.
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Document ID: 0B971FA1

Fundamentals Of Natural Gas Safety
Author(s): Linton T. Lipscomb
Abstract/Introduction:
Natural Gas: A combustible mixture of methane and higher hydrocarbons used chiefly as fuel and raw material. To safely produce natural gas and natunil gas products, a basic understanding of the hazards of the material itself and the processes required to bring it to maiket is essential. Lets start out with the hazards of natural gas as it is in its raw field gas state:
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Document ID: 9345DB69

Direct Measurement Of Energy, Description Of Equipment, Methods, And Calculations
Author(s): Thomas E. Sowell
Abstract/Introduction:
Why measure total gas energy as opposed to volume at base conditions? It is a matter of economic fairness. With open access to pipelines and the right to negotiate gas contracts on an interstate or even international basis. Heating values, (the overall quality of natural gas), has become an additional variable to factor in the usage of gas as a commodity. In the past gas quality was relatively constant due to the chain of custody linking a particular field or fields to particular customers. Open access has radically changed that concept. The Federal Energy Regulatory Commission (FERC) now mandates custody transfer to be accomplished on an energy basis. This effectively adds calorific value as another variable in the calculation of billings for custody transfer.
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Document ID: 5125310B

Report On API Egm Standard
Author(s): Brent E. Berry
Abstract/Introduction:
Since this report references both itself and the 21.1 standard, the following nomenclature has been adopted to make it clear which document is being referenced. report - references this document, the one you are now reading. standard references the 21.1 standard, unless otherwise noted. section and subsection both refer to portions of the API 21.1 standard. document is a generic term that could be referencing either document. Hopefully the context will make it clear which document is being referenced.
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Document ID: F9B80A03

H2S Detections And Determination
Author(s): James W. Canterbury
Abstract/Introduction:
Hydrogen sulfide (H2S) and total sulfur, in varying amounts, are found in almost all natural gas fields. In some cases, it is so small that the product is referred to as sweet gas. Many fields, however, produce sour gas, which is a gas with an H2S and total sulfur level high enough to require its removal or sweetening. Several methods are available to do this sweetening. However, that is a separate subject and not a part of this paper. The following material is designed to increase your knowledge of hydrogen sulfide, total sulfur and the different continuous monitoring equipment used today. Also covered are different installation techniques concerning placement of the equipment, and proper wiring technique for alarm circuits and recorder outputs. The use of a sample preparation system is also covered.
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Document ID: 1683039B

Methods Of Gathering Egm Data
Author(s): Roland Rollins
Abstract/Introduction:
The choices of ccmununication options presently available are: radio/microwave (RS-232), telephone (land line and cellular), wire or short haul (RS-485), VSAT (very small aperture), LSAT, or a combination of these. LSAT is a DC powered satellite system in which the dish need not be aligned with the satellite. It was first used in the tnicking industry. The following table highlights the main capabilities and limitatitms of each type of communication option available. A combination of methods often is needed, so dont overlodc a mixed system.
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Document ID: FE38E2CE

Basic Electronics For Field Measurement
Author(s): D. R. Looper
Abstract/Introduction:
This paper hopefully affords readers a broad brushed overview of electronics basics and how they are utilized in todays increasingly technical world. There are references to established formulas and relationships as well as a discussion on some state-of-the-art technology- The latter is often short changed in these types of presentations and it seemed a good idea to hit some of these basics, too. Perhaps the discussion herein will prove at least informative to those that have limited exposure to computer technology.. This understanding is more and more vital to the successful implementation of computerized measurement and automation systems in our Natural Gas Industry.
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Document ID: 62D3598E

Instruments For The Determination Of Specific GRAVITY/RELATIVE Density Of Gas
Author(s): Myles Mcdonough
Abstract/Introduction:
The terms Specific Gravity and Relative Density have been used for a number of years. Yet there seems to be some confusion over what exactly they mean. Specific Gravity is formally defined as the ratio of gas density to air density wbea both are at standard conditions of 0 Degree C and 760 mm. Over the years the definition evolved to beccone the ratio of gas density to air density at the same temperature and pressure, Relative to each other. Hence, the torn Relative Density.
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Document ID: 0B34DE48

Operation Of On-Line Chromatograph
Author(s): Paul E. Kizer
Abstract/Introduction:
On line gas chromatography is today being chosen more and more in the natural gas industry for monitoring of gas quality. The calculations of the gas volumes in modem electronic flow meters requires not only BTU (A BTU, British Thermal Unit, is a measure of heat) information, but specific gravity, Mol. % CO2 and Mol. % N2 as well. In addition, the current AGA-8 supercompressibility equations also require a complete analysis for the detailed method of calculation of Fpy. Most natural gas custody transfer contracts today use MMBTU rather than MCF as the accounting units of gas transfer. Also, modem micropacked columns are providing faster cycle times for time critical BTU measurement applications. For these reasons mentioned above, and the fact that the installation requirements for chromatographs are less stringent than calorimetric methods, the use of gas chromatographs has become standard practice.
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Document ID: 659EF0CE


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