Cross-Validation of ECVT and MRI measurements With Applications to Gas-Solid Fluidized Bed

Q. Marashdeh1, D.J. Holland2, F, Wang1, T.C. Chandrasekera2, M. Pore2, J.S. Dennis2, L.S. Fan1, and L.F. Gladden2

1 Department of Chemical & Biomolecular Engineering, Ohio State University, Columbus, OH 43210, USA

2 Department of Chemical Engineering & Biotechonology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge, Cambridgeshire, CB2 3RA, UK

ABSTRACT

Electrical Capacitance Volume tomography (ECVT) and Magnetic Resonance Imaging (MRI) are two prominent imaging technologies that have gained increased attention for imaging multi-phase flow systems. Each technique exhibits unique features that make it more suitable for specific settings. ECVT can be applied to image small and large scale reactors and is limited in resolution, whereas MRI is restricted in size but can provide images with very high resolution. MRI is currently limited to a 50 mm diameter system and has a resolution of 1.5 mm for fast imaging and about 100 µm for slow imaging. An objective of this study is to estimate the true resolution achieved with ECVT. Both techniques also differ in their imaging speed. ECVT is capable of providing 80 capacitance frames per second; each capacitance frame can be reconstructed as a 3D image. The imaging speed for MRI depends on the detail required in each data set. For 1D and 2D MRI, 1000 and 40 data sets are available per second, respectively.

In this work, we cross-validate the applicability of both techniques to multi-phase flow imaging. Both techniques are used to image gas-solid flow in a bubbling bed. Specifically for jet behaviour, the variation in solids concentration from the top of the distributor to the top of the bed using both techniques is being investigated. Three different types of distributors are used, two-holes, three-linear- holes, and three-triangular-holes.

The results of this work are positioned to form a basis for utilizing both technologies to improve understanding of multi-phase flow systems. MRI is used here primarily as a tool to study small scale fundamentals of the underlying physics. The MRI results can be used to enhance the accuracy and quantitative use of ECVT toward better understanding the scale up effects in large systems that are difficult to image by MRI.

Keywords ECVT, MRI, Mutli-phase flow, process imaging