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676 HWAHAK KONGHAK Vol. 40, No. 6, December, 2002, pp. 676-680 (2001 7 2 , 2002 8 5 ) A Study on the Analysis of Measurement Errors of Specific Gravity Meter Kang-Jin Lee , Jae-Young Her, Young-Cheol Ha, Seung-Hee An, Seung-Jun Lee and Cheol-Gu Lee Fluid Measurement Research Division, R & D Training Center, KOGAS, Ansan 425-790, Korea (Received 2 July 2001; accepted 5 August 2002) , . . , , , , . Abstract - The specific gravity meter is the instrument used to measure the density of fluids under the reference conditions and it can be widely used in industrial areas, especially in massive flow rate natural gas industry. This study has been carried out in an attempt to improve measurement accuracy of natural gas flow rate calculation, providing the adequate installation and proper operation conditions of specific gravity meter. The test results are 1) the density measurement errors in case of using methane and standard gas as calibration gases are smaller than using methane and nitrogen gas, 2) the periodical calibration to maintain accurate density measurements is essential, and 3) the specific gravity meter is sensitive to changes of environmental conditions, especially environmental temperature surrounding the specific gravity meter. Key words: Natural Gas, Base Density, Specific Gravity Meter, Gas Chromatograph, Calibration 1. . , . 2 [1-3]. ( ) [4, 5], P-V-T . , . 2 [6, 7]. [8, 9], . KOGAS( ) , , . 2. Fig. 1 . KOGAS (Solartron NT 3096) 0.1% of reading [10]. To whom correspondence should be addressed. E-mail: [email protected]

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Page 1: A Study on the Analysis of Measurement Errors of …cheric.org/PDF/HHKH/HK40/HK40-6-0676.pdf · GPA(Gas Processors Association) ... GPA Standards 2145, “Table of Physical Constants

HWAHAK KONGHAK Vol. 40, No. 6, December, 2002, pp. 676-680

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A Study on the Analysis of Measurement Errors of Specific Gravity Meter

Kang-Jin Lee†, Jae-Young Her, Young-Cheol Ha, Seung-Hee An, Seung-Jun Lee and Cheol-Gu Lee

Fluid Measurement Research Division, R & D Training Center, KOGAS, Ansan 425-790, Korea(Received 2 July 2001; accepted 5 August 2002)

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Abstract − The specific gravity meter is the instrument used to measure the density of fluids under the reference conditionsand it can be widely used in industrial areas, especially in massive flow rate natural gas industry. This study has been carriedout in an attempt to improve measurement accuracy of natural gas flow rate calculation, providing the adequate installation andproper operation conditions of specific gravity meter. The test results are 1) the density measurement errors in case of usingmethane and standard gas as calibration gases are smaller than using methane and nitrogen gas, 2) the periodical calibration tomaintain accurate density measurements is essential, and 3) the specific gravity meter is sensitive to changes of environmentalconditions, especially environmental temperature surrounding the specific gravity meter.

Key words: Natural Gas, Base Density, Specific Gravity Meter, Gas Chromatograph, Calibration

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HWAHAK KONGHAK Vol. 40, No. 6, December, 2002

Page 3: A Study on the Analysis of Measurement Errors of …cheric.org/PDF/HHKH/HK40/HK40-6-0676.pdf · GPA(Gas Processors Association) ... GPA Standards 2145, “Table of Physical Constants

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HWAHAK KONGHAK Vol. 40, No. 6, December, 2002

Page 5: A Study on the Analysis of Measurement Errors of …cheric.org/PDF/HHKH/HK40/HK40-6-0676.pdf · GPA(Gas Processors Association) ... GPA Standards 2145, “Table of Physical Constants

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����

1. Alan T., Hayward� J.: “Flowmeters, A Basic Guide and Source

Book for Users,” 111(1979).

2. Wilson. C. W.: “Gas Density and Specific Gravity,” 47(1987).

3. The Basic Principles and Practice of Flow Measurements, Natio

Engineering Laboratory, 23(1988).

4. Jaeschke. M., Hinze. H. M.: “Using Densitometers in Gas Meterin”

Hydrocarbon Processing, June, 37(1987).

5. John, H. Day.: “Application of Densitometer to Orifice Meters

A.G.A Operating Section Transmission Conference, 67(1968).

6. IGU Sub-Committee C2 Report, International Gas Union(1993).

7. Lee, K. J. and Her, J. Y.: “A Study and Analyzing Error Sources and

Establishing Normal Operational Schemes of Gas Densitomet

KOGAS Report(1996).

8. ISO 6976: “Natural Gas-Calculation of Calorific Values, Densit

Relative Density and Wobbe index from Composition,” International

Organization for Standardization(1995).

9. AGA Report No. 8, “Compressibility Factors of Natural Gas an

Other Related Hydrocarbon Gases,” American Gas Association(1992).

10. 3096 Specific Gravity Transducer-Technical Manual, Schlumberger(19

11. GPA Standards 2145, “Table of Physical Constants of Para

Hydrocarbon and Other Components of Natural Gas,” Gas Proces-

sors Association(1993).

12. GPA Standards 2172, “Calculation of Gross Heating Value, Rela

Density and Compressibility Factor for Natural Gas Mixtures fro

Compositional Analysis,” Gas Processors Association(1986).

Fig. 9. Density errors due to environmental temperature variations.

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