Measuring-hydrocarbon-dew-point

Author: Sohrab Zarrabian

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Hydrocarbon Dew Point (HDP) remains one of the key quality parameters of natural gas streams. Its determination is needed for operational and safety considerations, as well as to satisfy tariffs and regulations in US and overseas pipeline operations. The recent development of shale gas in US has added to the need for accurate and consistent measurement of HDP across a range of different mixtures of natural gas.

Theoretical methods for prediction of natural gas have been used in the past, but have been shown to have significant errors associated with them1. In general, theoretical methods using GC component analysis and EOS models have too much error to be useful. Direct measurements, using a chilled-mirror, continue to remain the preferred method for measurement of HDP.

We introduced our line of hydrocarbon and water dewpoint measurement instruments about 5 years ago. These analyzers utilize CEIRSTM technology, which is a novel implementation of the chilled-mirror principle. It utilizes IR spectroscopy to not only detect the dewpoint but also whether it was a water dewpoint or hydrocarbon dewpoint.

We have collected the data from our analyzers corresponding to approximately 20 years worth of data. In this paper, we discuss some of the findings from the analysis of this data.