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Korean Chemical Engineering Research,
Vol.53, No.4, 496-502, 2015
천연가스의 탄화수소 이슬점 측정방법 비교 연구
A Study on the Comparison of Methods for the Measurement of Hydrocarbon Dew Point of Natural Gas
탄화수소 이슬점은 천연가스 응축형태를 특성화하는 가장 일반적이고 자주 이용되는 물성으로 가스 품질 사양의 중요한 항목이다. 탄화수소 이슬점은 미량의 고탄화수소 성분에도 매우 민감한 것으로 알려져 있어, 특히 천연가스를 공급하는 가스 회사 입장에서는 기존 합의된 가스 사양을 만족하는 것 뿐만 아니라, 발생된 탄화수소 응축물에 의해 운영설비 및 안전에 심각한 문제를 일으킬 수 있으므로 탄화수소 이슬점을 정확하게 구하는 절차를 확립하는 것이 중요하다. 본 연구에서는 실제 현장조건 하에서 탄화수소 이슬점을 측정하기 위해 냉각 거울 방식의 이슬점 측정기를 설치, 운영하였으며, 측정된 이슬점 온도는 가스분석기에 의해 분석된 조성 및 천연가스 산업계에서 인정된 상태방정식을 이용하여 계산된 이슬점 온도와 비교하였다. 시험 결과 탄화수소 이슬점 측정기는 매우 안정되게 이슬점을 측정하였으며, 이슬점 측정기를 검증하기 위한 시험 가스로는 순수 프로판 가스가 적정하였다. 제조 표준가스 및 실제가스의 측정결과를 가스분석기에 의한 간접 측정 결과와 비교시에도 적정한 범위 내에서 일치하는 것을 확인하였다.
Hydrocarbon dew point(HCDP), a property which is the most generally used for describing natural gas condensation, is a very important parameter of natural gas quality specifications. HCDP is strongly influenced by the concentration of the heavier hydrocarbon components, especially C6+, so, along with compliance with gas quality specifications, build up of procedures for obtaining accurate HCDP is essential for gas transmission company, because hydrocarbon condensation present may cause serious operational and safety problems. This study has been carried out in an attempt to measure HCDP accurately by the automatic hydrocarbon dew point meter under the actual field conditions. Measured HCDP also has been compared with calculated HCDP using the composition determined by gas chromatograph and industry accepted equation of state at multiple pressures, along with the cricondentherm. The test results are 1) the automatic hydrocarbon dew point meter was able to measure stable HCDP continuously 2) the automatic hydrocarbon dew point meter has been performed reference measurement by pure propane with a known dew point from literature, and 3) A meaningful differences was observed when comparing the automatic hydrocarbon dew point meter and gas chromatograph results for synthetic standard gas mixtures and real gas mixtures.
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