Dual-Energy X-Ray Tomography in Process Engineering - A Non-Intrusive Technique to Characterise Vertical Multiphase Flows

T. Grassler and K.E. Wirth

Lehrstuhl fuer Mechanische Verfahrenstechnik, Universitaet Erlangen-Nuernberg Cauerstrasse 4, 91058 Erlangen/GERMANY

Phone: ++49-9131-852-9400, E-mail: sekretariat@mvt.uni-erlangen.de

ABSTRACT

Since years conventional x-ray tomography has been successfully used to study the flow structures of vertical gas-solids flows. Now, the additional implementation of a dual-energy technique makes it possible to investigate multiphase flows like an injection of liquid educts in a gas-solids fluidized bed or a reaction progress in a three-phase bubble column. The x-ray tomography system mainly consists of an 160 kV/640W x-ray source, which can be operated at different energy levels, and an x-ray linear detector with 1024 sensitive elements. With a dual-energy technique the dependence of the materials absorption coefficients on the x-ray energy is used. A number of static test objects composed of two different materials have been investigated to simulate technical applications like mixing or drying processes of granulated material. Additionally, the dual-energy x-ray tomography system has been applied to determine the solids, liquid and gas distribution in a three-phase bubble column in order to show the possibilities of this measuring technique.

Keywords Tomography, X-Ray, Dual-Energy, Multiphase Flow