FILTRATION PERFORMANCE TEST – EXPERIMENTAL RESULTS AND CASE STUDIES
David Chezaud (pages 219-225)
This paper describes some of the features of new equipment for laboratory scale filtration testing. Descriptions are provided for the Filtration Performance Test, which facilitates the automated acquisition of constant pressure filtration data, and Filtration Performance Software which facilitates data analysis, including the automated calculation of characterising parameters such as specific cake resistance and filter cake compressibility. Exemplar experimental data are presented to show equipment and analysis performance in relation to repeatability measurements, filtration cell diameter, particle diameter and particle shape. The use of the approach to aid process scale equipment specification is also considered and some examples are provided.
FILTER MEDIA DEVELOPMENT WITH COMPUTATIONAL FLUID DYNAMICS
GKD – Gebr. Kufferath AGK (pages 225-230)
This paper presents two studies of how computational fluid dynamics (CFD) has been used by GKD to improve the performance of filter media and aid the determination of characterising parameters. In the first study CFD is used to help specify a more robust filter medium for an oil/gas application which consequently facilitated higher daily production rates. In the second study CFD is used as a numerical simulation of the well-known bubble point test and favourable comparisons are made with experimental measurements.
COMPRESSIBILITY OF FILTER CAKE FORMED IN THE DEADEND ULTRAFILTRATION OF NANOCOLLOIDS
Eiji Iritani, Nobuyuki Katagiri, YukikoTakaishi and Koji Hattori (pages 231-240)
The properties, especially cake compressibility, of the filter cake formed in deadend ultrafiltration were examined using nanocolloids of bovine serum albumin (BSA) solutions at pH 5.1 (around the isoelectric point) and 7.0, and nanosilica sol. Although average porosity of the filter cake formed in the ultrafiltration of nanosilica sol varied significantly with the applied filtration pressure, the variation of average specific cake resistance with the applied pressure was not as pronounced when compared to results obtained with the BSA solutions.
The specific surface area of solid particles, evaluated from the relation between the local specific cake resistance and local cake porosity derived from the flux decline behaviour in deadend ultrafiltration with the aid of the Happel cell model, was examined. It was revealed that BSA molecules easily deformed compared to silica nanoparticles under the action of the solid compressive pressure generated from the filtrate flow in ultrafiltration. Moreover, it was found that BSA molecules at pH 5.1, the isoelectric point, deformed more significantly than those at pH 7.0 due to the compression force. This was also backed up from the relation between the specific surface area and solids compressive pressure over a relatively low solids compressive pressure range obtained by measuring the sedimentation velocity and equilibrium thickness of the compressed sediment in analytical ultracentrifugation of BSA solutions.