IN-SITU, FIBER-OPTIC MEASUREMENT TECHNIQUES IN CARBON
DIOXIDE EXPANDED LIQUID (CXL) MULTIPHASE REACTORS
S.G. Mueller1,2, M.H. Al-Dahhan1,2, M.P. Dudukovic1,2
1
2
Department of Energy, Environmental, and Chemical Engineering,
Chemical Reaction Engineering Laboratory (CREL), Washington University in St. Louis,
One Brookings Drive, St. Louis, Missouri 63130 USA
Sm2@cec.wustl.edu, muthanna@seas.wustl.edu, dudu@seas.wustl.edu
Dense phase carbon dioxide, including liquid and supercritical CO2, has been gaining
acceptance for potential use in industrial applications due to benefits of pressure-tunable
density and transport properties, reduction of conventional solvent use, enhanced miscibility
of reactants, optimized catalyst activity, and increased product selectivities, all of which
decrease waste and pollution. CO2 expanded solvents (CXL’s) also provide the benefit up of
to 80% solvent replacement with a dense phase fluid such as carbon dioxide (Wei et al.,
2002). However, analysis and modeling of expanded solvents and supercritical phase reactors
are lacking. Also, physical properties of these mixtures are highly sensitive to changes in
pressure, temperature, and composition. Therefore, a reliable understanding of phase
behavior and critical phase behavior is necessary for both experimentation and modeling.
To gain a better understanding of phase behavior, as well as provide an online
measurement tool, in-situ, fiber-optic probes have been developed to measure volumetric
expansion (Mueller et al., 2007), to detect the phase transition from the subcritical to
supercritical phase, and to characterize bubble dynamics in multiphase reactors. These
properties are essential for modeling and determining phase separations, the amount of
solvent and/or catalysts required as well as catalyst solubility. The objectives of this work
are: 1) to advance the use of fiber optic probe measurement techniques into high pressure,
high temperature, and multiphase reactors and 2) to quantify bubble dynamics in multiphase
stirred tank reactors and 3) to quantify important phase behavior parameters in order to
advance the fundamental understanding of CXL’s.
This work was supported by the National Science Foundation Engineering Research Centers
Program, Grant EEC-0310689