Smart Reactors–Additively Manufactured Lattice Structures (AMLS) for Tailoring Gas-Liquid Flows

08.03.2021

-  Claas Spille, M.Sc.,  Institute of Multiphase Flows -

The ever-increasing demands for resource- and climate-friendly processes in process engineering require innovative and flexible solutions for reaction control. However, new methods in the field of material sciences and additive manufacturing are now opening up completely new possibilities for equipping traditional processes with sensors and actuators and thus making them ”smarter". This is the main goal of the joint I3-Lab project "Smart Reactors", in which Additively Manufactured Lattice Structures (AMLS) are developed and their influence on fluid dynamics of a two-phase flow is investigated. The structures, e.g. Periodic Open-Cell Structures (POCS) as the simplest subclass of AMLS can be custom-made from various materials and adapted to the specific requirements of the selected process. AMLS can be used e.g. to define the bubble size and phase distribution inside a gas-liquid contactor depending on the cell geometry of the unit cell. In Figure 1 the influence of POCS on the local gas holdup as well as on the bubble size distribution is shown [1]. Besides, the structures themselves can be covered with catalysts like immobilized enzymes for a biochemical reaction. This was already successfully shown in close collaboration with the Institute of Technical Biocatalysis (ITB) [2]. Furthermore, recent investigations regarding the material choice of those structures lead to new degrees of freedom in how structures can be designed to autonomously react to changing process conditions inside a chemical reactor. 

It is now possible to print structures made of stimulus-responsive materials, which reversibly change their shape due to e.g. temperature and pH changes. This allows the reaction conditions within a two-phase flow to be optimally adjusted for a chemical or biochemical reaction, for example with regard to pressure loss, bubble size distribution, and interfacial area, in order to achieve higher yields and selectivities or to be able to react flexibly to e.g. changing raw materials [3]. Figure 2 shows the adjustment of the transport parameters by reversible shrinking or expanding of responsive additively manufactured lattice structures. The ongoing work is done in close collaboration with the Institute of Thermal Separation Processes (TVT). 

In the future, AMLS will be tested for a heterogeneously catalyzed chemical reaction (epoxidation of propylene to propylene oxide) in collaboration with the Institute of Chemical Reaction Technology (CRT), and further investigations on material and surface properties will be carried out in collaboration with the Institute of Laser and System Technologies (iLAS).

References

  1. C. Spille et al., “SMART-Reactors: Tailoring Gas Holdup Distribution by Additively Manufactured Lattice Structures”, Chemical Engineering & Technology, July 2020, doi: 10.1002/ceat.202000211
  2. N. Büscher et al., “Counter-Currently Operated Reactive Extractor with Additively Manufactured Enzyme Carrier Structure”, Organic Process Research & Development. 24 (9), 1621-1628.
  3. X. Hu, C. Spille, M. Schlüter, and I. Smirnova, “Smart Structures—Additive Manufacturing of Stimuli-Responsive Hydrogels for Adaptive Packings,” Ind. Eng. Chem. Res., vol. 59, no. 43, pp. 19458–19464, Oct. 2020, doi: 10.1021/acs.iecr.0c03137.