Abstract:

Nature is a rich source of ideas to innovate chemical engineering. Looking at nature may help us to reach important objectives such as sustainability, multi-functionality, effectiveness or scalability. More often than not, symmetries and dynamic patterns in nature have a function. Complex processes are realized in unexpected ways. I will present a few examples from our research on chemical engineering designs that are inspired by natural processes, without necessarily imitating them.

Inspired by the structure of the lungs, fractal injectors were constructed that distribute a fluid in a uniform way throughout a vessel containing another fluid or particles with which it reacts. The process is easily scalable, despite the complexity of multiphase fluid dynamics. Remarkably, the structure of the lung is also shown to minimize entropy production, an interesting feature to increase thermodynamic efficiency.

By disturbing their dynamics, regular patterns are formed in very complex systems, such as the surface of sand dunes or altocumulus clouds. Likewise, by fluctuating the incoming fluid flow, gas-liquid bubble columns or gas-solid fluidized beds may be made regular. While here there is no one-to-one relationship between the natural and the manmade system, nature tells us that dynamics and periodic perturbations should not be neglected as a way to achieve very different, and perhaps more desirable results.

Trees are remarkable chemical reactors. They are a prime example of intricate multi-scale structure-function relationships. Inspired by trees and leaves, we optimized the hierarchical pore network structure in porous materials to be used in catalysis or other applications, such as controlled release or fuel cells. Progress in nanomaterials makes it possible to synthesize materials with this optimized pore structure at different lengthscales.

Manmade membranes perform in many ways poorly compared to cell membranes, which combine high fluxes and selectivities. By studying the dynamics of molecules and ions in membrane protein channels, some essential underlying features are detected that may allow the design of high-flux, highly selective separation processes, e.g., for water purification, desalination, or bioseparations.

These are only a few of the many ways in which a closer observation of nature, from the viewpoint of a chemical engineer, may allow us to come up with radically different solutions to attack the considerable sustainability issues facing us today.