Interface detection with electrical resistance tomography applied in thickening process

Mika Mononen1,2, Marko Vauhkonen1,2, Villesamuli Normi1,2, Juha Reunanen2, Jari Kaipio1,2,3 and Anssi Lehikoinen1,2

1University of Eastern Finland, Dept. of Physics and Mathematics, POB 1627, 70211 Kuopio, Finland

2Numcore Ltd., POB 1199, 70211, Kuopio, Finland

3University of Auckland, Department of Mathematics, New Zealand

ABSTRACT

In this paper we describe a technique to measure the locations of phase interfaces (bed levels) in industrial processes, especially in thickening process. The measurement approach is based on ERT (Electrical Resistance Tomography) type technology in which the conductivity distribution of the object is estimated based on the current-voltage data of the measurement device. In this paper we introduce a novel probe technique for estimating the bed level in thickeners. The estimation is based on a non- linear regularization technique with the assumption that the conductivity distribution changes only in vertical direction. Substantial reduction in the complexity of the underlying inverse problem can thus be achieved. Two different types of probes are simulated and tested with several realistic bed level cases.

Keywords electrical resistance tomography, bed level, thickener, regularization, probe