Data Preprocessing of In Situ Laser‐Backscattering Measurements

Abstract

In situ measurement techniques are promising tools to aid process development. However, they also pose new challenges in evaluating large amounts of recorded data. A new procedure for in situ laser-backscattering devices has been developed that allows transformation of the raw recorded data, a chord length distribution, into a format suitable for population balance modeling. Emphasis is thereby laid on the influence of the suspension density on the measured data. Experimental data are recorded using a batch laboratory crystallizer equipped with an in situ 3D-ORM laser backscattering device and an ultrasound probe. The new proposed five-step procedure for data preprocessing is based on several independently developed tools from literature and is exemplarily illustrated with results on the crystallization of ascorbic acid. The proposed method is a step forward to use in situ laser-backscattering devices also for quantitative purposes.

Total Synthesis of (–)‐Isoamericanin A and (+)‐Isoamericanol A

“…The MSZW can be determined by considering the changes in solution or solid phase properties upon the onset of nucleation, and different properties have been exploited for the detection of the MSZW, such as changes in density, viscosity, conductivity, turbidity, refractive index, etc. Thus, many techniques have been developed for the determination of the MSZW: visual observation using hot‐stage microscopy or bulk video imaging 3, 4; detection of the presence of solid particles using focused beam reflectance measurements (FBRM) 5–8 or a laser nephelometer 9–11; monitoring the solute concentration in the solution by attenuated total reflection‐Fourier transform infrared spectroscopy (ATR‐FTIR) 5–7, 12; ultrasonic velocity measurements 13; and monitoring the electrical conductivity 14, density 15, refractive index 16, or dielectric constant 17.…”

Computing Crystal Size Distribution by Focused‐Beam Reflectance Measurement when Aspect Ratio Varies

“…Therefore, it is essential for CSD to be obtained online in manufacturing processes. Process analytical technologies (PATs) such as optical reflectance measurement [11][12][13], online image processing [14][15][16][17], focused-beam reflectance measurement (FBRM) [18][19][20][21], etc. are increasingly used for in-line measurement of CSD.…”

Online monitoring of drop/particle size and size distribution in liquid–liquid dispersions and suspension polymerizations by optical reflectance measurements

“…Based on the results of Simmons et al ., the laser back scattering probes have been widely used in the fields such as sizing cell cultures, nucleation or crystallization processes . The techniques of focused beam reflectance measurement (FBRM) and 3D optical reflectance measurement (ORM) have been successfully applied in monitoring the dynamic solid–liquid or gas–liquid processes, crystallization processes, and liquid–liquid biocatalytic reactor . However, the applications of FBRM and ORM techniques in the suspension polymerization are rare.…”