Inline Analyzing of Industrial Crystallization Processes by an Innovative Ultrasonic Probe Technique

The mean particle size and suspension density of industrial ammonium sulfate and urea crystals were measured by a single ultrasound sensor in a saturated solution at only one frequency. The information on ultrasound velocity and attenuation were combined and related to characteristic properties of the solid phase of suspensions. By model identification, a correlation between the measured signals and mean particle size as well as suspension density were evaluated and verified by additional experiments. The measurements with different particle size fractions and different suspension densities up to 40 wt‐% were carried out isothermally. The approach of coupled ultrasound velocity and attenuation provides a simple technique for inline process control on the liquid and solid state of a suspension process like solution crystallization only by a single measurement device.