Electrical capacitance tomography (ECT) is an imaging method mainly capable of reconstructing dielectric permittivity. Generally, the reactance part of complex admittance is measured in a selected frequency. This paper presents for the first time an in depth and systematic analysis of complex admittance data for simultaneous reconstruction of both electrical conductivity and dielectric permittivity. A complexvalued forward model, Jacobian matrix and inverse solution are developed in the time harmonic excitation mode to allow for multi-frequency measurements. Realistic noise models are used to evaluate the performance of complex admittance ECT in a range of excitation frequencies. This paper demonstrates far greater potential for ECT as a versatile imaging tool through novel analysis of complex admittance imaging using a dual conductivity permittivity inversion method. The paper demonstrates that various classes of contactless capacitance based measurement devices can be analysed through complex multi-frequency ECT.

Complex-Valued, Multi-Frequency ElectricalCapacitance Tomography (CVMF-ECT) is a recently developed tomographic concept which is capable to simultaneously reconstruct spectral permittivity and conductivity properties of target objects within the region of interest. To date, this concept has been limited to simulation and another key issue restricting its wide adoption lies in its poor image quality. This paper reports a CVMF-ECT system to verify its practical feasibility and further proposes a novel image reconstruction framework to effectively and efficiently reconstruct multi-frequency images using complex-valued capacitance data. The image reconstruction framework utilizes the inherent spatial correlations of the multi-frequency images as a priori information and encodes it by using Multiple Measurement Vector (MMV) model. Alternating direction method of multipliers was introduced to solve the MMV problem. Realworld experiments validate the feasibility of CVMF-ECT, and MMV based CVMF-ECT method demonstrates superior performance compared to conventional ECT approaches.

Please cite only the published version using the reference above.See http://opus.bath.ac.uk/ for usage policies.Please scroll down to view the document. ABSTRACT-Three-phase flow imaging is a very challenging problem in industrial process tomography. A particular interest here is three phase flow including both conductive and non-conductive phases. Currently there is no robust solution to this problem. Electrical capacitance tomography (ECT) has been applied to visualise the permittivity distribution by measuring inter-capacitance between electrodes around sensing area. Magnetic inductance tomography (MIT) is a technique to image the conductivity distribution through the inductance measurements over the coils around the sensing area. In this paper, the three-phase flow is classified into two scenarios: air background and water background. A dual-modality method of ECT and MIT is proposed to image both the conductive and dielectric components under test. As a result of this experiment, the dual-modality method is able to solve air-background three-phase flow imaging, but a problem has been raised in the waterbackground scenario. The static experiment results are promising for such contactless three phase flow imaging. Dual modality ECT-MIT multi-phase flow imaging

Pipeline deposits are a worldwide problem facing the process industry affecting all phases of production, transmission and distribution causing problems to the pipeline operations up to the customer delivery point. Therefore, monitoring the propagation of such deposits at different points of the pipeline network will help taking more adequate preventive actions. Several good technologies are available in the market nowadays for monitoring deposits but Electrical Capacitance Tomography (ECT) technique in particular promises superior advantages as it is considered fast, compact, safe, easy to interpret and cost effective. However, ECT still suffers from one disadvantage being the poor resolution, thus this study suggest the use of ECT with limited region tomographic image reconstruction using a narrowband pass filter to enhance the resolution of the produced images. The experimental results showed that different deposits regimes and fine deposits could be detected with high definition and high resolution.

Oil–water two-phase flows are commonly found in the production processes of the petroleum industry. Accurate online measurement of flow rates is crucial to ensure the safety and efficiency of oil exploration and production. A research team from Tsinghua University has developed an experimental apparatus for multiphase flow measurement based on an electrical capacitance tomography (ECT) sensor, an electrical resistance tomography (ERT) sensor, and a venturi tube. This work presents the phase fraction and flow rate measurements of oil–water two-phase flows based on the developed apparatus. Full-range phase fraction can be obtained by the combination of the ECT sensor and the ERT sensor. By data fusion of differential pressures measured by venturi tube and the phase fraction, the total flow rate and single-phase flow rate can be calculated. Dynamic experiments were conducted on the multiphase flow loop in horizontal and vertical pipelines and at various flow rates.