Quantification of particle size and concentration using in-line techniques and multivariate analysis

We study means of extracting quantitative information about particle attributes using state-of-art in-line and off-line particle measurements and analysis techniques. The approach comprises a combination of image analysis, laser diffraction, inversion of chord length distribution, and multivariate analysis. Polystyrene particle suspensions are used as the model system to provide a wide range of particle loadings (up to 10 wt%), sizes (<90 to 800 μm) and shapes. We identify key challenges and limitation of the in-line imaging and chord length measurements; particularly, an upper limit of particle number density of 10,000 g⁻¹ is observed, as well as the impact of internal reflections from large and transparent particles. The latter phenomena deteriorate the accuracy of the chord length distribution and the subsequent particle size estimation using inversion algorithms. The study demonstrates the use of multivariate analysis for quantifying particle size and concentration, which yields relative errors of 6 and 11%, respectively.