Multivariate Statistical Process Control for On-line Monitoring Size of Milling Process

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Bundit Boonkhao
Xue Z. Wang


Ultrasonic attenuation spectroscopy (UAS) is an attractive process analytical technology (PAT) for on-line realtime characterisation of slurries for particle size distribution (PSD) estimation. It is however only applicable to relatively low solid concentrations since existing instrument process models still cannot fully take into account the phenomena of particle - particle interaction and multiple scattering, leading to errors in PSD estimation. This paper investigates an alternative use of the raw attenuation spectra for direct multivariate statistical process control (MSPC). The UAS raw spectra were processed using principal component analysis. The selected principal components were used to derive two MSPC statistics, the Hotelling's T2 and square prediction error (SPE). The method is illustrated and demonstrated by reference to a wet milling process for processing nanoparticles.


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A. S. Dukhin and P. J. Goetz. Ultrasound for characterizing colloids: Particle sizing, zeta potential, rheology, Elsevier, London. 2002.

M.J.W. Povey, “Acoustic methods for particle characterization”, KONA, vol. 24, pp. 126–133, 2006.

J.R. Allegra and S.A. Hawley, “Attenuation of sound in suspensions and emulsions: Theory and experiments”, Journal of the Acoustical Society of America, vol. 51, pp. 1545-1564, 1972.

P.S. Epstein and R.R. Carhart, “The absorption of sound in suspensions and emulsions. I. Water fog in air”, Journal of the Acoustical Society of America, vol. 25, pp. 553-565, 1953.

C.M. Atkinson and H.K. Kytömaa, “Acoustic wave speed and attenuation in suspensions”, International Journal of Multiphase Flow, vol. 18, pp. 577-592, 1992.

J.M. Evans and K. Attenborough, “Coupled phase theory for sound propagation in emulsions”, Journal of the Acoustical Society of America, vol. 102, pp. 278-282, 1997.

A.K. Hipp, G. Storti and M. Morbidelli, “On multiple-particle effects in the acoustic characterization of colloidal dispersions”, Journal of Physics D: Applied Physics, vol. 32, pp. 568-576, 1999.

T. Oja, J.G. Dosramos, R.W. Reed, “Acoustic analysis of concentrated colloidal systems” in L.T. Provder, J. Texter (Eds.), Particle sizing and characterization, ACS symposium series, vol. 881, American Chemical Society, Washington, pp. 231-248, 2004.