Concentration Measurement of Oil-Water Two-Phase Flow in Electrical Capacitance Tomography System

摘要

Concentration is one of the most important parameters in oil-water two-phase flow, and it is of great significance to get on an accurate measurement for concentration in the course of production and engineering control. Electrical Capacitance Tomography (ECT) technique, which can calculate the space distribution of dielectric constants in the inner of objects by measuring EC values between electrodes around the surface of objects, is being mainly applied to detect multiphase flows in industrial pipelines. And the technique also can offer visual information that conventional instruments can not detect in closed pipelines or containers, such as concentration, distribution, motion state of non-conducting multiphase. The subject investigated of this paper is major in the ECT system of 8-electrode oil-water two-phase flow, and the measuring principle is analyzed. At the same time we present the method of image reconstruction to accomplish the concentration measurement of oil-water two-phase flow. In ART image-reconstruction algorithm, we present threshold value to improve quality of image reconstruction and calculating accuracy of content, and generally the measurement error is about 1%. Such method can well solve many defects that other measurement methods have, such as slow speed, high cost, and poor security and so on. Therefore, it offers a new method for the concentration measurement of oil-water two-phase flow.