Conditioning of Flowing Multiphase Samples for Chemical Analysis
Thomas J. Bruno
The chemical analysis of process streams is a common task that must be completed thousands of times every day in the chemical industry. In refineries, at gas wells, in chemical processing plants and in fine pharmaceutical facilities, there is a continual need for the chemical analysis of products and intermediates. Less common but no less important are the many instances in which such process samples must be handled in state of the art analytical chemistry labs. Unlike the typical samples presented in the analytical laboratory, process streams are seldom well behaved. Very often, process streams present multiphase samples to the analytical device. In this context, multiphase means that there is a gaseous or vapor phase plus one or more liquid phases. Because of the complexities of vapor/liquid equilibrium, a multi phase (two or more phase) mixture cannot be analyzed reliably. Sample conditioning is required before any analysis is attempted. This means that the gaseous and liquid fractions of the sample are separated into two distinct regions or streams. Moreover, the two phases must be retained in the device with complete integrity. That is, they must not be changed in any way by the separation device. In this paper, a simple approach to conditioning such multiphase samples is described. This approach permits the reliable analysis of both phases.