The Research of High Voltage Electrical Capacitance Tomography System

Abstract

The electrical capacitance tomography (ECT) was used to detect multiphase flows in pipelines, fluidization process and combustion phenomena in internal combustion engines, and so on. In the mentioned applications, none of them has equipment or vessel with inner diameter exceeding 1 meter. Nevertheless, there are some of large equipments like blast furnaces, coal bunkers and so on, need to detect its content distribution. These requirements could be met by ECT technology. But there are not any ECT systems can be used to detect content distribution of those large equipments, because the existing system can not measure the capacitance in change which was changed by content distribution. A new method of high AC voltage excitation and C/V circuits which has a higher excitation voltage about 20~50 times than the previous ac-based system, with an 8-electrodes sensor array that is amounted on a 2.5m inner diameter object constructed a High Voltage Electrical Capacitance Tomography (HVECT) system in laboratory. Image reconstruction experiments show that the HVECT is applicable to monitor the content distribution in the future.

Impedance matched electrical capacitance tomography system: front-end design and system analysis

“…As discussed in section 1, the measurement accuracy can be increased either by the usage of high excitation frequencies or high excitation voltages. Systems utilizing high excitation voltages, employ high voltage MOSFETs [37] or mechanical relays [38]. ECT systems operating at high excitation frequencies, enable the use of off the shelf analog switches.…”

Imaging irregular structures using electrical capacitance tomography

“…For some applications, it is necessary to deal with a high temperature environment [10] (e.g. in pulverised coal combustion and oil catalytic cracking), and to use conical ECT sensors [11] (e.g. for cone bin measurement), and more complicated ECT sensors (e.g.…”