In-situ multi-phase flow imaging for particle dynamic tracking and characterization: Advances and applications

[Display omitted] •The advances of the imaging hardware for real-time image capturing are discussed.•The high-efficiency image processing algorithms are summarized.•Applications of in-situ imaging in multi-phase flow monitoring are reviewed.•Challenges and opportunities for in-situ imaging analysis in multi-phase flow are discussed. Real-time chemical process monitoring, analysis, and control have become increasingly important to multi-phase flow process research and development and attracted overt attention during the recent decades. In-situ image-based process analytical technology which benefited from the fast development in imaging hardware and AI-based algorithms has achieved great progress in the area of multi-phase flow processes. This review work summarizes the advances of the imaging hardware for real-time image capturing and the algorithms for image processing. Insights based on the advanced examples in multi-phase flows (industrial crystallization, dissolution, fluidization, emulsification) are provided to inspire the applications and development of real-time process imaging analysis. It concludes that the recently developed imaging hardware can meet the demands (image field, resolution, magnification) in different scenarios, and the AI-based algorithms have superior abilities (accuracy, efficiency, migrating application capability) in image segmentation and classification. The usage of image-based in-situ process analytical technology provides intuitional tracking and data-driven process monitoring, analysis, and control of multi-phase flow processes. Finally, challenges and opportunities for the development of in-situ image-based process analytical technology in multi-phase flows are discussed.