Local and global process intensification

• Definitions of local and global intensification.
• Illustration of the limits of the local intensification approach.
• Impact of local intensification on overall process efficiency.
• Process intensification by flowsheet architecture improvement.
• Process optimization through economics, safety and sustainability drivers.

The present paper aims at proposing a complementary view of process intensification (PI) based on the concepts of local intensification and global intensification. Local intensification is defined here as the classical approach of PI based on the use of techniques and methods for the drastic improvement of the efficiency of a single unit or device. Some examples are given to illustrate that local process intensification presents several limitations when compared to holistic overall process-based intensification, named global intensification. Indeed, when PI focuses on single units (reactors, separators, hybrid separators, etc.), the strong interactions among all units within the process are ignored and the impact of local intensification of a single unit can be very limited, resulting in weak improvement of the whole process. This paper identifies that process intensification is broader than technical improvement of devices or processes and has to consider several drivers such as economics, safety, eco-efficiency and sustainability to fulfill the key objectives in designing new plants and retrofitting existing units.