In-Situ Monitoring of Batch Crystallization by Ultrasound Spectroscopy

Abstract

The possibility of using acoustic spectroscopy for the on-line and in-situ monitoring of particle size distributions and volume concentrations in batch crystallization processes is investigated. First, the acoustic technique is discussed, along with the evaluation of the involved model parameters. Second, for a seeded cooling crystallization of potassium sulfate (K 2 SO 4 ) in a supersaturated aqueous solution, it is shown that both size and concentration of the growing crystals can be estimated simultaneously from measured acoustic attenuation spectra. The results are discussed in view of the potential application of this technique to real-time and in-situ monitoring and control of industrial processes.

Ultrasonic crystallization monitoring technique for simultaneous in-line measurement of liquid and solid phase

“…The progress of a crystallization process (solid phase) can, however, be followed most efficiently by means of the suspension density and the mean crystal size [26] (shown e.g. in [13,18,22]), which is calculated from the CSD [27].…”

“…These techniques include, but are not limited to, conductivity [6], density [7], turbidity [8], ultrasonic (single frequency) [9,10], in-line microscopy [11], laser backscattering (FBRM or 3D ORM) [5,[12][13][14], laser diffraction [15], attenuated total reflection-Fourier transform infrared (ATR-FTIR) [16] or ultrasonic attenuation spectroscopy (UAS), which correlates ultrasonic attenuation with a spectra of frequencies [4,[17][18][19][20][21][22]. All these techniques are established and applied to monitor/control crystallization processes.…”

Effects of concentration of dispersions on particle sizing during production of fine particles in wet grinding process

“…Takeda and Goetz [6] and other researchers like Hibberd et al [7] use the technique for characterization of flocculation in different applications. The applications of the technique in domain of crystallization may be consulted in the work of Hipp et al [8], Mougin et al [9], Li et al [10], etc. However, sufficient work has not been performed yet in application of the technique in fine wet grinding processes which are typical in the sense: (i) The change in average particle size of the product is rapid in the grinding mill due to breakage of particles.…”

On-Line Crystallization Process Parameter Measurements Using Ultrasonic Attenuation Spectroscopy

“…The neural networks were readily trained and it took fewer than 100 iterations to reach the desired MSE. The results show that the neural network with 20 hidden neurons gave the best approximating C ) R f r (D,σ) -R f r _b R f r _intrinsic (6) results. The recovered results obtained by the neural network compared with the true values of the intrinsic attenuation are given in Table 3.…”