An Overview of Current Insights and New Perspectives for Semi-Industrial Applications of Cavitation Reactors

This overview is intended to shed light on the current state of knowledge on highly efficient cavitation reactors, which are used in industry yet often remain undisclosed. The development of ultrasound (US) and hydrodynamic cavitation (HC) reactors requires a thorough understanding and precise engineering to ensure the efficacy of cavitation processes in larger industrial settings. Successful scaling-up must maintain a high energy density and ensure a homogeneous distribution of cavitation. Industrial reactor designs for both US and HC are typically optimised for continuous flow operations, though some configurations operate in a loop system. This review provides a concise examination of various reactor setups, with examples of relevant chemical and environmental applications, focusing on energy consumption and scalability challenges. Despite the similarities in the effects of acoustic and hydrodynamic cavitation, US and HC are best regarded as complementary technologies in industrial applications. This work presents our direct experience in designing novel cavitation reactors for specific applications, incorporating recent advances from the literature and insights from industry. Notably, the synergistic effects of hybrid technologies are gaining attention, particularly the integration of HC with cold plasma, which is emerging as one of the most effective techniques for treating polluted water. These technologies play a crucial role in modern process engineering, and continued advancements in their design and understanding will further expand their industrial applications in chemical processing.