Capacitive and Wireless Gas Holdup Sensing in a Loop Reactor Using a Magnetically Coupled Resonant Circuit

We introduce a novel wireless sensing technique for gas holdup measurement within the inner draft tube of a loop reactor. A magnetically coupled resonant circuit senses the changes in the permittivity of the liquid phase, induced by variations in gas holdup and is wirelessly interrogated. For this purpose, a capacitive sensor consisting of a pair of annular-shaped electrodes is used. The measurements are carried out in an experimental setup that replicates the configuration of the area of interest of the loop reactor. For the evaluation, an impedance analyzer is used to detect changes in the phase plot at coupling frequencies. A major benefit of this method is that it enables nonintrusive measurements without affecting the flow behavior of the loop reactor, offering a significant advantage over conventional approaches.