Use of a scattered light sensor for monitoring the dispersed surface in multimodal system

The article presented here deals with the quality parameter dispersed surface in material systems like suspensions or dispersions in which several phases are present simultaneously such as solids in continuous solution. Here, other quality parameters are relevant for the quality of the products than, for example, in pure solutions or gases. The dispersed surface is relevant for reaction rates, absorption capacity, and many other properties of the suspension. In contrast to the common method of measuring particle size distributions and solid concentrations in a complex manner, the article shows that the use of a simple scattered light measurement is also sufficient for disperse phase measurement. Based on previous investigations with monodisperse material systems "Use of a scattered light sensor for monitoring the dispersed surface in crystallization" (Schmitt et al., Chem. Ing. Tech., Bd. 94, Nr. 8, S. 1177-1184, 2022), the optical effect of mixtures of fine and coarse particles is discussed here. It is shown that the dispersed surface can also be determined directly in materials characterized by very broad particle size distributions using scattered light probes. In addition to the pure measurement results, the description of the measurement setup and derived findings, the article deals with several side aspects of disperse-phase systems. The specific dispersed surface of the dispersed phase in suspensions, emulsions, bubble columns, and aerosols plays a decisive role in increasing heat and mass transfer processes. This has a direct impact on the space-time yield in large-scale chemical process engineering production plants. The results obtained contribute to a comprehensive understanding of the dispersed surface and enable improved control and optimization strategies in the chemical engineering industry.