Development of capacitance tomographic imaging systems for oil pipeline measurements

UMIST is one of the establishments where process tomography techniques were first developed. This paper introduces the development of capacitance tomographic imaging systems at UMIST for oil pipeline measurements. The principles of electrical capacitance tomography (ECT) are briefly presented and two ECT systems based on charge/discharge capacitance measuring circuits are described. These systems, a PC-based 8-electrode system and a Transputer-based 12-electrode system, have been used to visualise oil pipelines. Future developments of ECT technology are discussed, including a low-cost PC-based ECT system, a twin-plane ECT system which can measure the velocity profile of a pipeline flow, a multi-frequency ECT system using ac capacitance measuring circuits and an ECT system with a rotating parallel excitation field.