라만분석기는 분자가 가지는 고유 진동에 빛을 조사하여 발생하는 빛의 산란이 생기는 “라만효과”를 이용하여 분

자 구분과 성분 분석을 할 수 있는 분석기로, 천연가스 산업에서도 LNG(액화천연가스) 수출 및 수입 기지 외에 벙

커링 및 탱크로리 분야에서도 폭 넓게 사용 중이다. 본 연구에서는 실제 현장 조건하에서, LNG 성분 분석 및 주요

물성(발열량, 기준밀도 등)을 산출하기 위해 LNG 수입기지에 라만분석기를 설치, 운영하였으며, 측정된 LNG 성분

및 발열량을 기존 검증되어 운영 중인 가스분석기에 의해 분석된 성분 및 발열량과 비교하였다. 시험 결과 라만분석

기는 매우 빠르고 안정되게 LNG 성분 및 발열량을 측정하였으며, LNG 거래의 기준이 되는 발열량을 기존 가스분

석기 결과값과 비교시에도 적정 오차 기준 내에 있는 것을 확인하였다. 추가적으로 본 연구를 통해 얻은 측정 결과

는 관련 표준(ASTM D7940-14)의 정확도 기준을 만족하였고, 국외 대규모 실증 사례와의 비교 시에도 유사한 결과

를 산출하였다.

Raman analyzer is an analytical technique that utilizes the “Raman effect”, which occurs when light is scattered by the inherent vibrations of molecules. It is used for molecular identification and composition analysis. In the natural gas industry, it is widely used in bunkering and tank lorry fields in addition to LNG export and import terminals. In this study, a LNG-specific Raman analyzer was installed and operated under actual field conditions to analyze the composition and principal properties (calorific value, reference density, etc.) of LNG. The measured LNG composition and calorific value were compared with those obtained by conventional gas chromatograph that are currently in operation and validated. The test results showed that the Raman analyzer provided rapid and stable measurements of LNG composition and calorific value. When comparing the calorific value, which serves as the basis for LNG

transactions, with the results from conventional gas chromatograph, the Raman analyzer met the acceptable error criteria. Furthermore, the measurement results obtained in this study satisfied the accuracy criteria of relevant international standards (ASTM D7940-14) and demonstrated similar outcomes compared to large-scale international demonstration cases.

Raman analyzer (Raman Spectroscopy), LNG (Liquefied Natural Gas) quality, Gas chromatograph, Calorific value

1. Shell LNG Outlook 2023(2023).
2. Gas Insight, International LNG Market Assessment in 2022,
KOGAS Research Institute of Economics & Management(2023).
3. GIIGNL, Annual Report 2023 Ed, GIIGNL(2023).
4. Prasanth S., Scott S., and Dandee B., Measurement of Success,
LNG Industry(2020).
5. GIIGNL, LNG Custody transfer handbook 6th Ed, GIIGNL(2021).
6. ISO 8943, Refrigerated light hydrocarbons fluids – Sampling of
liquefied natural gas – Continuous and intermittent methods,
International Organization for Standardization(2007).
7. Martin, V., GERG performance evaluation on a Raman application
against LNG custody transfer limits, GERG(2021).
8. GERG(The European Gas Research Group) Home Page, Projects/
LNG/Raman method for determination and measurement of
LNG composition(2022).
9. Scott, S. and Martin, V., Raman method for custody transfer
measurement of LNG, Endress Hauser(2022).
10. ISO 6976, Natural gas - Calculation of calorific values, density,
relative density and Wobbe indices from composition, 3rd Ed,
International Organization for Standardization(2016).
11. Foil, A. M. and Helen, R. G., The infrared and Raman spectra of
cyclohexane and cyclohexane-d12, Mellon Institute, vol. 20, issue
10, 1517-1530(1964).
12. Choi, M. K., Understanding Raman spectroscopy in LNG analysis,
Raman Research Institute(2021).
13. Ju, W. S., Lee, K. J., Go, Y. J., Mo, Y. G., Lee, S. H. and Kim, Y.
C., Demonstration for LNG Quality Analysis using Raman
Spectroscopy, KOGAS Report(2022).
14. ISO/TR 147496, Natural gas – Online gas chromatograph for
upstream area, 1st Ed, International Organization for Standard-ization(2016).
15. ASTM D7940-14, Standard Practice for Analysis of Liquid Natural
Gas (LNG) by Fiber-Coupled Raman Spectroscopy, American
Society for Testing Materials(2014).