기준 밀도계의 측정 오차 분석에 관한 연구

이강진; 허재영; 하영철; 안승희; 이승준; 이철구; Kang-Jin Lee; Jae-Young Her; Young-Cheol Ha; Seung-Hee An; Seung-Jun Lee; Cheol-Gu Lee

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

Export Citation

기준 밀도계의 측정 오차 분석에 관한 연구

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

이강진^†, 허재영, 하영철, 안승희, 이승준, 이철구

한국가스공사 연구개발원 유체계량연구실, 안산 425-790

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

E-mail:

초록

기준 밀도계는 기준 조건하에서 밀도를 측정하는 기기로서, 산업계에서 특히 대유량 천연가스 계량에 폭 넓게 사용된다. 본 연구에서는 기준 밀도계의 적정 설치 및 운영방안을 제시하여 천연가스 유량 측정 정확도를 향상시키고자 현장 실험을 수행하였다. 실험 결과, 교정가스로 메탄과 질소가스 대신 메탄과 표준가스로 교정한 실험결과가 작은 밀도오차를 발생하고, 정확한 밀도 측정을 위해서는 정기적인 교정이 필수적이며, 또한 기준 밀도계는 수위 조건에 민감하게 반응하여, 수위 온도가 높으면 오차가 증가하는 것도 확인되었다.

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.

Keywords:Natural Gas;Base Density;Specific Gravity Meter;Gas Chromatograph;Calibration

[References]

Alan T, Hayward J, "Flowmeters, A Basic Guide and Source-Book for Users," 111 (1979)
Wilson CW, "Gas Density and Specific Gravity," 47 (1987)
The Basic Principles and Practice of Flow Measurements, National Engineering Laboratory, 23 (1988)
Jaeschke M, Hinze HM, Hydrocarb. Process., June, 37 (1987)
John HD, "Application of Densitometer to Orifice Meters," A.G.A Operating Section Transmission Conference, 67 (1968)
IGU Sub-Committee C2 Report, International Gas Union (1993)
Lee KJ, Her JY, "A Study and Analyzing Error Sources and Establishing Normal Operational Schemes of Gas Densitometer," KOGAS Report (1996)
ISO 6976: "Natural Gas-Calculation of Calorific Values, Density, Relative Density and Wobbe Index from Composition," International Organization for Standardization (1995)
AGA Report No. 8, "Compressibility Factors of Natural Gas and Other Related Hydrocarbon Gases," American Gas Association (1992)
3096 Specific Gravity Transducer-Technical Manual, Schlumberger (1992)
GPA Standards 2145, "Table of Physical Constants of Paraffin Hydrocarbon and Other Components of Natural Gas," Gas Processors Association (1993)
GPA Standards 2172, "Calculation of Gross Heating Value, Relative Density and Compressibility Factor for Natural Gas Mixtures from Compositional Analysis," Gas Processors Association (1986)

[1] Alan T, Hayward J, "Flowmeters, A Basic Guide and Source-Book for Users," 111 (1979)

[2] Wilson CW, "Gas Density and Specific Gravity," 47 (1987)

[3] The Basic Principles and Practice of Flow Measurements, National Engineering Laboratory, 23 (1988)

[4] Jaeschke M, Hinze HM, Hydrocarb. Process., June, 37 (1987)

[5] John HD, "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 KJ, Her JY, "A Study and Analyzing Error Sources and Establishing Normal Operational Schemes of Gas Densitometer," KOGAS Report (1996)

[8] ISO 6976: "Natural Gas-Calculation of Calorific Values, Density, Relative Density and Wobbe Index from Composition," International Organization for Standardization (1995)

[9] AGA Report No. 8, "Compressibility Factors of Natural Gas and Other Related Hydrocarbon Gases," American Gas Association (1992)

[10] 3096 Specific Gravity Transducer-Technical Manual, Schlumberger (1992)

[11] GPA Standards 2145, "Table of Physical Constants of Paraffin Hydrocarbon and Other Components of Natural Gas," Gas Processors Association (1993)

[12] GPA Standards 2172, "Calculation of Gross Heating Value, Relative Density and Compressibility Factor for Natural Gas Mixtures from Compositional Analysis," Gas Processors Association (1986)