Am. Jwayyed et al., HIGH-PRESSURE FLOW GRAVIMETRIC APPARATUS FOR SUPERCRITICAL-FLUID EXTRACTION STUDIES, Review of scientific instruments, 68(12), 1997, pp. 4542-4548
An experimental apparatus has been developed for real time measurement
s of fluid-solid adsorption (or desorption) rates and equilibria at el
evated pressures. In addition to controlling pressure and flow rates s
imultaneously, this setup is able to operate at higher flow rates than
previously possible in supercritical fluid experiments. The system co
nsists of a high pressure microbalance, two high pressure syringe pump
s, and an absorbance detector. The microbalance enables the collection
of data at a greater time resolution, resulting in a more accurate me
asurement of rate data. Because of the dual syringe pump design, there
is no pressure drop in the system, making it possible to operate at a
wide range of flow rates (at experimental conditions). The buoyancy f
orce was measured with helium experiments, while the hydrodynamic forc
es were measured using a clean solid sample and supercritical carbon d
ioxide at different flow rates. It was found that the hydrodynamic for
ce increased with flow rate as expected. The apparatus was tested by c
onducting two desorption experiments of phenol from activated carbon a
t 141+/-0.07 bar, 36.0+/-0.02 degrees C, and 0.47 ml/min (at experimen
tal conditions). The amount of phenol removed was 16.4% and 18%, respe
ctively! in the two runs which is consistent with previously published
results and indicates the difficulty of regenerating activated carbon
loaded with phenol. (C) 1997 American Institute of Physics.