Energy efficiency and sustainability are major factors towards mitigating the depletion of fossil fuel reserves and the environmental impact of their consumption. Tight integration is a key enabler towards achieving these goals, both in existing chemical plants, but also in emerging technologies for power generation and for production of fuels and chemicals from renewable resources.
The first part of the talk will focus on the dynamics and control of tightly integrated process networks. Recent results will be presented which establish that process networks with large rates of material and / or energy recovery and recycle, exhibit dynamics over multiple time scales, with individual units evolving in a fast time scale with weak connections, which become significant over slower time scales giving rise to a slow evolution of the entire process network. A model reduction method based on singular perturbations will be described which allows obtaining a hierarchy of low-order nonlinear models valid in the different time scales. A graph reduction analogue of this method which can be fully automated will also be described. This multi-time-scale analysis lends itself naturally to a hierarchical control framework, whereby network-level control objectives can be effectively addressed at a slow, supervisory level.
The second part of the talk will focus on the emerging theme of distributed production of power, fuels and chemicals, using renewable resources. The motivation lies in the promise of developing efficient, sustainable and robust infrastructures utilizing local resources. The challenges span science, technology and public policy considerations. Recent results along with exciting opportunities for systems research will be highlighted, on two broad fronts: micro-grids and bio-refineries.