A CAPACITANCE-BASED TOMOGRAPHY SYSTEM FOR INTERFACE MEASUREMENT IN SEPARATION VESSELS

Optimal quality of the product that leaves a water/oil/gas separator i s determined by optimal separator design and control. Current control strategies for separators are extremely simple due to the lack of a re liable interface level measurement system. In this project a capacitan ce-based tomography system for interface imaging inside a separator ha s been developed and tested in the separator laboratory at Christian M ichelsen Research (CMR). The tomography system consists of a capacitan ce sensor system, a data acquisition system and a model-based reconstr uction algorithm implemented on a personal computer. The system can po tentially measure the water, oil/water emulsion, oil and foam heights inside a separator on a process plant. In this project the tomograph h as been tested, in a separator laboratory at CMR, for on-line imaging of water, oil and air interface levels (during water/oil/air tests) an d for oil, foam and air interface imaging (during oil/air tests). The obtained accuracy is within 1.0 cm for all phases. The tomograph also detected the presence of foam, but due to problems with electrostatic charge generation, poor stability in the measurements results. In a st eel separator, however, it is expected that the electrostatic charge p roblem will probably not exist.