058 Solids Phase Chromatography
Wei Yang and Yulong Ding
Institute of Particle Science & Engineering, University of Leeds, Leeds, LS2
9ND, y.ding@leeds.ac.uk
ABSTRACT
Solids Phase Chromatography (SPC) is a novel technology for particle sizing and
classification under dry conditions. The method eliminated disadvantages of dispersing
particles into suspensions that is necessary to many particle sizing techniques. SPC utilises
gas flows to fractionate particles according to size when the size is the primary concern.
Dissimilar to common chromatography, there is no stationary phase present. The key of the
success of the method relies on the proper construction of flow fields. Referring to
Hydrodynamic Chromatography (HDC), a 2 metre packed column of 2 mm spheres was used
to form the flow fields. The glass ballotini and microcrystalline cellulose (MCC) were tested at
various gas velocities. The results showed that the elution of particles is in the order of larger
to smaller sizes, exactly the same as in HDC. However, numerical simulation by Discrete
Element Method (DEM) revealed that the fractionation mechanisms seemed to depend mostly
on the differences in the degree of the particle dispersion inside the packing structures.
Particle size analysis was achieved based on the pressure measurements at the packed
column. Pressure data was processed to obtain Δt which is the time difference of pressure
waves, generated by the injection of particles, between inlet and the point 40 cm above inlet.
It was found that Δt linearly increased with increasing particle sizes. A plot of Δt·Ug/H against
d/dp showed that all of data collapse into one linear relationship at moderate errors. Here, Ug
is gas velocity, H is 40 cm, and dp is the diameter of packed particles. DEM simulation
quantitatively agrees with the experiments.
The second part of the experiments was conducted by using a 10 metre helical coil. Only
particle classification was principally examined. In breakthrough curve measurements, the
results showed that the elution orders of the particles are generally from larger to smaller
when the coil was vertically placed. Material sorting in the same manner was also
investigated. The results revealed that MCC is the fastest elute followed by glass ballotini,
while sands having the same density with glass ballotini are the last elute.
Keywords
particle, size measurement, classification, dry