From process integration to process intensification

• Novel approach for discovering intensification opportunities in integrated process flowsheets.
• Rigorous comparison of the dynamics of integrated and intensified processes.
• Theoretical justification of the loss of control degrees of freedom due to intensification.

In this paper, we establish a connection between process integration and process intensification. Focusing on processes with material recycle, we use an asymptotic analysis to demonstrate that intensification represents a limit case of tight integration through significant material recycling. Based on this result, we propose a novel avenue for discovering intensification opportunities at the process design stage. Subsequently, we investigate the dynamics and control implications of the transition from process integration to process intensification. We demonstrate that, for the same steady-state performance, the dynamic response of an integrated process is slower than that of its intensified equivalent. Also, we provide a theoretical justification for existing empirical arguments concerning the loss of control degrees of freedom caused by process intensification. The theoretical developments are applied on a reaction–separation–recycle process example.