Modelling of an ECT/ERT Dual-modality Tomography Sensor for Oil/Gas/Water Three-component Flow Measuring

P. Jiang1, L. Peng1, G. Lu1, D. Xiao1 and H. Wang2

1Department of Automation, Tsinghua University, Beijing, China, Email: lihuipeng@tsinghua.edu.cn

2Department of Automation, Tianjin University, Tianjin, China

ABSTRACT

Electrical capacitance tomography (ECT) and electrical resistance tomography (ERT) are two representative techniques of process tomography. ECT is more applicable when applied to materials which are of low electrical conductivity, such as oils, plastics, dry powders and pure water under favourable circumstances; while ERT is much better when applied to materials with high electrical conductivity. Since both ECT and ERT only work under certain circumstances of oil/gas/water distributions, neither ECT nor ERT could separately meet the requirements of oil/gas/water three- component flow measurement. For this reason, we present an ECT/ERT dual-modality tomography sensor applicable for the measurement of oil/gas/water three-component flow with wide range of component changes. Our ECT/ERT dual-modality tomography sensor is made up of 24 electrodes mounted in the same cross section. The capacitance electrodes and resistance electrodes are mounted alternately along the inner surface of the vessel. In addition, the capacitance electrodes are covered with isolation material to avoid contact with conductive materials. The capacitance electrodes and resistance electrodes work alternately. When the capacitance electrodes work, the resistance electrodes are suspended. While the resistance electrodes work, the capacitance electrodes are floating. The finite element method is used to analyse the ECT/ERT dual-modality sensor. Numerical results show the feasibility of ECT/ERT dual-modality tomography for oil/gas/water three-component flow measuring.

Keywords Electrical capacitance tomography, Electrical Resistance tomography, ECT/ERT dual modality tomography, Finite element method