Imaging a Gas-Sparged Stirred-Tank Reactor With X-Ray CT

Abstract

X-ray computed tomography (CT) is used to explore the differences in gas dispersion in a gas-sparged stirred-tank reactor (STR) for different operating conditions. X-ray CT imaging is completed for various impeller speeds and gas flow rates in a 0.21 m ID STR made out of acrylic and equipped with a nylon Rushton-type impeller. From the CT slices, major differences in local time-averaged gas holdup can be seen, depending on the operating condition. Completely dispersed conditions have a relatively uniform holdup profile while flooded conditions have an increase in gas holdup towards the center of the tank. The high resolution of the X-ray system allows for visualizing time-averaged gas flow details such as low gas holdup regions directly above the impeller region under certain operating conditions and recirculation regions behind the baffles.

Visualizing fluidized beds with X-rays

“…Iowa State University developed the X-ray Flow Visualization (XFloViz) facility in the Experimental Multiphase Flow Laboratory to study multiphase flows using noninvasive Xray techniques. This facility and its development have been thoroughly explained in the literature (Ford 2006;Ford et al, 2007;Heindel et al, 2005;Heindel et al, 2008;Striegel, 2005), and only a summary is provided in section 3.4. The X-ray equipment is described in the first subsection, followed by a discussion of important X-ray parameters in the second subsection.…”

Ultrasonic Time-of-Flight Computed Tomography for Investigation of Batch Crystallisation Processes

“…Ultrasonic measurements have proven to offer solutions in fermentation, solidification and crystallisation processes in the food or pharmaceutical industry [ 16 , 17 , 18 ]. Many recent studies have been focused on tomography’s potential in the monitoring of crystallisation and stirred tanks’ functionality [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. This is the first study that investigates the application of USCT travel-time tomography results for the crystallisation process in stirred tanks.…”