International Society for Industrial Process Tomography

Liquid Distribution and Fraction Measurement in Counter Current Flow Packed Column by Electrical Capacitance Tomography

Hao Wu^1,2, Bill Buschle¹, Yunjie Yang¹, Chao Tan², Feng Dong², Jiabin Jia^1*, and Mathieu Lucquiaud¹

¹School of Engineering, University of Edinburgh, Edinburgh, United Kingdom

²School of Electrical and Information Engineering, Tianjin University, Tianjin, China

^*Email: Jiabin.Jia@ed.ac.uk

ABSTRACT

Electrical capacitance tomography (ECT) is used to analyse the distribution of a liquid phase across the packing of a counter current gas-liquid packed bed column and to quantify the liquid fraction present on the packing. liquid fraction is quantified with a new proposed ECT measurement method that combines an algorithm with a calibration method that only requires vacant and dry calibration steps. Liquid distribution is analysed using established tomography image reconstruction methods. 2D with gas/packing and 3D with gas/liquid/packing simulations using the finite element method (FEM) are employed to validate the quantification method. An experiment is conducted on a counter current gas-liquid packed bed column with polypropylene Sulzer Mellapak 250 Y as the packing. Two liquids with low and high electrical conductivities (NaCl solution, 0.1 mS/cm and 30 mS/cm respectively) are floated in the facility and tested at various liquid load to study the effects of liquid phase electrical properties. Assessment of reconstructed images based on ECT measurements at various conditions shows that ECT is able to qualitatively detect both liquid distribution patterns and the magnitude of liquid present on the packing. Liquid fraction measurements using ECT and the proposed method were compared with two other methods that determined liquid fraction volumetrically from tank level difference measurements and from time-lapsed video image capture of the column respectively. Comparison of the methods shows that using ECT with the proposed method is able to effectively determine the liquid fraction present on the packing within an estimated measurement uncertainty of 2%. Given this performance it is believed the combination of ECT and the proposed liquid fraction quantification method could be well suited for reliable in-situ real-time determination of liquid phase distribution and liquid fraction in industrial gas processing and post-combustion carbon capture applications.

Keywords Liquid Fraction; Liquid Distribution; Electrical Capacitance Tomography; Packed Column; Calculation Model

Industrial Application Carbon Capture