The Principles and Domains of Process Intensification

Apply the fundamental principles of process intensification to the four domains of PI — spatial, thermodynamic, functional, and temporal — to identify possible PI opportunities.

Twenty years have passed since the publication of the seminal paper “Process Intensification: Transforming Chemical Engineering” (1) in the January 2000 issue of Chemical Engineering Progress. During those 20 years, many important developments in the field of process intensification (PI) have taken place worldwide. This article and the next one in this special section discuss those developments, focusing on the fundamental theoretical basis of PI and on the practical aspects of selecting intensified equipment.

Born in the industrial laboratories of Imperial Chemical Industries’ (ICI’s) New Science Group (2), process intensification, from its very beginnings, has been a practice-driven branch of chemical engineering. Until the early 1990s, PI research concentrated mainly on developing novel processing equipment and methods in four areas: high-gravity operations, compact heat transfer, intensive mixing, and hybrid techniques. Gradually, the practice of PI expanded to new fields, such as microreactors and alternative energy sources.

The toolbox view of PI presented in the January 2000 article (1) was also very much practice-oriented, as it divided PI into two sub-domains (Figure 1):

• process-intensifying equipment, such as novel reactors and mixing, heat-transfer, and mass-transfer devices
• process-intensifying methods, such as hybrid separations; integrated reaction and separation, heat exchange, and/or phase transition (in so-called multifunctional reactors); techniques using alternative energy sources (e.g., light, ultrasound, etc.); and new process control methods (e.g., intentional unsteady-state operation).

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▲Figure 1. The PI toolbox includes process-intensifying equipment and process-intensifying methods. Source: (1).

This toolbox view was the first attempt at a systematic approach to PI. It has been widely accepted by the community and has been cited often in the PI-related literature...