A review of process intensification applied to solids handling

Process intensification (PI) is a strategy aimed at transforming conventional chemical processes into more economical, productive and green processes. Its fundamental concept hinges upon the volume reduction of processing equipment resulting in enhanced mixing and heat/mass transfer as well as a multitude of other benefits. To date, the focus of PI has been on processes mainly involving gas/liquid systems. Solids handling applications have been more limited as fouling and blockages can occur due to large concentrations of solids in smaller equipment sizes. Appropriately designed equipment is therefore a key consideration for intensifying industrially-relevant solids handling processes. In this review paper, we highlight a number of solid processing applications including precipitation, separation, granulation and milling, etc. where PI has been demonstrated. Much effort has been directed at reactive crystallization and precipitation in various intensified technologies, exploiting their enhanced mixing capabilities to produce uniformly distributed nano-particles. Generally, the objective in many of these processes has focused on transforming solids handling in batch processes into continuous ones with processing time reduction and improved energy efficiency. The review highlights the considerable opportunity for further development of multifunctional technologies in solids handling applications such as granulation and drying, the subject of a European Commission-funded HORIZON 2020 project.