Multimodal Two-Phase Flow Measurement Using Dual Plane ECT and GRT

Abstract

The present work assesses the accuracy two phase flow measurement, based on cross-correlation and cross-spectrum velocity computation, using dual plane non-intrusive Electrical Capacitance Tomography (ECT), over a broad spectrum of horizontal flow configurations, combined with fraction distribution measurements from Gamma-ray Tomography (GRT). The measurement of two-phase flow encompasses the measurement of both the velocity and the phase concentration of the flow components. The accuracy of the flow velocity is still an open discussion and remains a key challenge in the field of multiphase flow measurement. The velocities of the two-phase components vary, both in between them, and across the pipe crosssection. This study assesses the use of cross-correlation techniques as methods for calculating the cross-sectional velocity distribution by deriving the transit time of the fluid flowing through two parallel ECT sensor arrays mounted on the perimeter of a pipe. The spectral distribution of the velocities is assessed for improved accuracy of individual component velocities. A dual-plane ECT is adopted for the velocity measurements and are combined with state-of-the-art density-based cross-sectional phase fraction distribution from a GRT system to measure the volumetric flow rates of the two phases. The results show that the cross-spectrum method provides enhanced velocity estimation for both flow phases over the conventional cross-correlation technique. Further improvement was reported using a simple predictive correction model resulting in flowrate estimation accuracy of ±10%.The method for two-phase flow measurement suggested in this work leverages the accuracy of the tomography systems on accurate fraction measurement and fast data acquisition to lead to potential enhancement in process control by enabling a more accurate prediction of components velocities.

Imaging measurement technologies for CCS

“…CO 2 or N 2 -(ii) the density of the sample, and (iii) the relaxation time. Velocities can also be measured using MRI without needing an additional measurement plane as in [21], and unlike other techniques, this is the only method where different velocities generate contrast.…”

“…Besides the above potential of the technologies to function independently, multimodal measurement can prove beneficial [21]. For example, a dual setup could consist of one technology sensible to fluid conductivity, like MIT or ERT and an adjacent system able to differentiate CO 2 and water from impurities, e.g., GRT or ECT.…”

ECT image reconstruction based on sensitive field expansion and optimization

“…ECT technology has been favored by many research institutes and scholars in recent years. And it has gradually become a research hotspot for the development of visualization detection technology, which is regarded as one of the most promising process tomography imaging technologies [7,8]. The importance of ECT is that it provides an effective means of solving many problems in practical applications.…”

Multimodal sensor suite for identification of flow regimes and estimation of phase fractions and velocities – Machine Learning Algorithms in Multiphase flow metering and Control

“…(Ameran et al, 2015) discuss velocity measurement of two-phase flow through ECT using cross-correlation techniques. A study of flow velocity and phase concentrations of horizontal two-phase flow is presented by (Stavland et al, 2021), employing a dual-plane ECT with gammaray tomography to measure volumetric flow rates of the phases, achieving an accuracy of ±10%. The results presented in this paper are developed during the master thesis's work of (Noorain Syed Kazmi, 2023).…”