Effect of Sampling Line Characteristics on the Dynamic Monitoring of Fluid Concentrations

Abstract

A novel approach is developed and demonstrated to characterize the sampling line effects during dynamic monitoring of fluid concentrations. The "sampling line" in this study refers to all components between the point of fluid sampling and the point of analyzer sensor. In general, sampling lines introduce errors in measurements by altering the sample properties due to the fluid transport in the line as well as the adsorption and desorption of fluid constituents on the surfaces of the sampling components that come into contact with the sample fluid. A methodology based on a sampling line simulator is developed for taking these effects into account and correcting the measurements. The model is validated by direct experimental measurements using several different analyzers under various conditions. The sampling line simulator can be used to analyze the effect of various sampling configurations and operating conditions; this would be helpful in the design of sampling lines and their location. An algorithm is proposed that can be used to convert concentration values measured and reported by the analyzer to the concentration values at the point of sampling that are the actual and desired values.