Ultrasonic levitation for the examination of gas/solid reactions
Abstract
An experimental setup based on acoustic levitation for the examination of gas/solid reactions is presented. In this setup single particles in the diameter range 1 mm-30 μm can be held against gravity for any wanted time in a defined gas atmosphere at elevated temperatures. The change of particle size, shape, and position can be measured and recorded using an optical device, consisting of a camera and a long range microscope. Basic experiments with inert particles of different shape and solid density have shown that the axial position of a reacting particle can be employed to derive its weight change. A method to evaluate this change of the recorded position for the according weight change is proposed. Exemplary results in the context of dry flue gas cleaning using Ca(OH)2 powder are presented. Single Ca(OH)2 particles are exposed to a well defined gas atmosphere and after some time these particles are retrieved from the ultrasonic field for further analyses. Only an in situ measurement of the particle weight change (i.e., without removing the particle from the well defined reactive atmosphere) brings information regarding the uptake of water by the sorbent, which accompanies SO2 and HCl absorption.
- Publication:
-
Review of Scientific Instruments
- Pub Date:
- October 2003
- DOI:
- 10.1063/1.1606532
- Bibcode:
- 2003RScI...74.4468K
- Keywords:
-
- 43.35.Zc;
- 43.25.Nm;
- 06.30.Dr;
- 68.43.-h;
- Use of ultrasonics in nondestructive testing industrial processes and industrial products;
- Acoustic streaming;
- Mass and density;
- Chemisorption/physisorption: adsorbates on surfaces