| Vol.4 No.1 Subject: Flow Measurement News Date: 1-16-02 From: McCrometer, "The Flow Measurement Specialists" ........ <<http://www.mccrometer.com>> ........ ******************************************* This newsletter is e-mailed by McCrometer monthly to subscribers worldwide. It consists of flow measurement information of interest for professionals in this field. For More information on our complete line of flowmeters go to: <<http://www.mccrometer.com>> ******************************************* McCrometer January 2002 Newsletter How Wet is Wet? As everyone in the flow measurement business knows, there is no one-size-fits-all definition of "wet gas". Broadly speaking, it describes a number of multiphase metering applications with high to very high gas volume fractions at the point of measurement. For many process engineers and oil & gas production engineers, "wet gas" is a gas saturated with water vapor, although no free liquid may be present. By this definition, the term "wet gas" could apply to the humid gas from separators, containing only traces of entrained liquid. In addition, however, "wet" applied to a gas can also mean that it contains free liquid, either hydrocarbon or water or both. In other words, "wet gas" is a multiphase fluid containing up to about 5% by volume of liquid. Some even consider fluids with about 10% by volume of liquid still as "wet gas" (A.W.Jamieson [1]). Yet another definition of "wet gas" is based on a modified Lockhart-Martinelli parameter, which is defined by de Leeuw [2] as the ratio of the liquid and gas Froude numbers. Choosing a fairly arbitrary upper limit of 0.35, for the parameter, corresponds to liquid volume fractions of approximately 7% and 12% for pressures of about 4 and 100 bar respectively. Whichever definition you use, there is no doubt that wet gas metering covers a very wide range of fluid conditions and is an extremely challenging area of measurement. For more information on McCrometer's products for wet gas metering, contact McCrometer at 951-652-6811 or visit our web-site at www.mccrometer.com <http://www.mccrometer.com>. Refs. 1. "Wet Gas Metering- The Unexpected Challenge Status and Trends on Technology and Applications" by A.W. Jamieson, 4C Measurement Ltd, North Sea Flow Workshop, Norway 2001. 2. "Liquid Correction of Venturi Meter Readings in Wet Gas Flow" by R. De Leeuw, Shell Expro, The Netherlands. North Sea Flow Workshop, Norway 1997. Copyright 2002 McCrometer |