TITLE: Pressure effects on bubble-column flow characteristics.

AUTHOR: D. R. Adkins;   K. A. Shollenberger;   T. J. O'Hern;   J. R. Torczynski.

INST.  AUTHOR: Sandia National Labs., Albuquerque, NM.

SPONSOR: Department of Energy, Washington, DC.


PUB.  TYPE: Technical Report

PUB.  COUNTRY: United States

SOURCE: Department of Energy [DE],  1996,  14p.


NOTES: National heat transfer conference (31st), Houston, TX (United States), 17-20 Aug 1996. Sponsored by Department of Energy, Washington, DC.


Bubble-column reactors are used in the chemical processing industry for two-phase and three-phase chemical reactions. Hydrodynamic effects must be considered when attempting to scale these reactors to sizes of industrial interest, and diagnostics are needed to acquire data for the validation of multiphase scaling predictions. This paper discusses the use of differential pressure (DP) and gamma- densitometry tomography (GDT) measurements to ascertain the gas distribution in a two-phase bubble column reactor. Tests were performed on an industrial scale reactor (3-m tall, 0.48-m inside diameter) using a 5-Curie cesium-137 source with a sodium-iodide scintillation detector. GDT results provide information on the time- averaged cross-sectional distribution of gas in the liquid, and DP measurements provide information on the time and volume averaged axial distribution of gas. Close agreement was observed between the two methods of measuring the gas distribution in the bubble column. The results clearly show that, for a fixed volumetric flowrate through the reactor, increasing the system pressure leads to an increase in the gas volume fraction or ''gas holdup'' in the liquid. It is also shown from this work that GDT can provide useful diagnostic information on industrial scale bubble-column reactors.

REPORT  NUMBER: SAND-96-0440C;   CONF-960815-2