Inline gas/liquid flow measurement using sequential static mixing elements

Abstract

This work explores the use of two sequential static mixers for the determination of mass flow and density of an effervescent two-phase mixture where compressibility effects remain relevant. The upstream static mixer exhibited a non-standard two-phase pressure drop correction factor (KL) due to flow homogenization dynamics, while the downstream static mixer exhibited more traditional KL vs. gas fraction trends. Through combination of the two mixers, mass flow rate was estimated to within ± 5 kg/h for the majority of conditions up to 100 kg/h and 70% gas fraction. Density estimates were comparable to those obtained from an in-line commercial Coriolis meter, with relative error consistently within ± 100 kg/m3 of actual bulk-phase densities. The configuration resulted in predictions comparable to an inline commercial Coriolis meter over a broad range of flow conditions, and represents a relatively inexpensive flow metering approach provided sufficient gas expansion is achieved to cause a variation in KL. Topic points•Use of sequential static mixers to normalize flow patterns in gas-liquid systems.•Introduction of a sudden expansion to induce gas fraction variation and a corresponding change in the 2-phase flow modifier, KL.•Comparison of calibrated results to a commercial Coriolis meter.