Determination Of Hydrocarbon Dew Point In Natural Gas

Author: Andy BentonDownload File

This paper considers the requirements for control of hydrocarbon dew point in natural gas and how measurement of this important gas quality parameter can be achieved. A summary of the commercially available on-line instrumentation is provided covering: • Manual, visual technique with chilled mirror dewpointmeter • Equation of state calculation from extended composition analysis by gas chromatograph • Automatic, optical condensation dewpointmeter The role of each measurement technology is described and assessed in terms of the effectiveness of the measurement method utilised together with other technical considerations as well as initial and operating cost implications. Full consideration is given to the specific difficulties to be confronted resulting from the complex nature of the parameter concerned. Such peculiarities include the effects of pressure, fractional condensation, the minute proportion of heaviest molecular weight components within the gas composition that contributes to the formation of condensate at the hydrocarbon dew point, and the overall subjectivity of the measurement itself where no absolute reference or definition is possible. A case is presented for the use of advanced optical techniques in an adaptation of the fundamental chilled mirror principle to provide automatic on-line measurement with a degree of objectivity and repeatability unobtainable with other measurement techniques