The use of 3D-printing in the study of chromatographic packed bed microstructures.
Thesis DisciplineChemical and Process Engineering
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Liquid chromatographic separations are typically performed in cylindrical columns with a random packing of spherical beads. The emergence of additive manufacturing, or 3D-printing has meant that novel column geometries can be printed to minimize band-broadening. Porous beds with perfectly ordered micro-structures, novel flow-distributor and column housing designs can be reliably manufactured achieve more efficient separations. This thesis investigates the effects of 3D-printed column mico-structures on a column’s plate height. First, the thesis describes the manufacturing and testing of proof-of-principle 3D-printed columns consisting of ordered porous beds, column walls, flow distributors, collectors and standard liquid chromatography fittings in a single printed artefact. Porous bed structures based on channels and particle-like elements were tested with radial and fractal distributor layouts, with the fractal distributor significantly reducing in the channel based geometries. Within particle-like elements, the effects of bed porosity, element shape and arrangement were tested using printed models.
Additionally, the effects of defects in porous beds were quantified by deliberately introducing well defined line defects into the bed design and experimentally testing the residence time distribution profiles. The penultimate chapter describes a set of geometries known as triply periodic minimal surfaces (TPMS) that were printed and experimentally tested. Monolithic structures known as network TPMS were shown to out-perform the best sphere packing column in minimizing band-broadening and flow resistance.
To the best of my knowledge, the work presented here represent the first steps towards 3Dprinted liquid chromatography columns. The adoption of 3D-printing as a column production method is currently limited by several key challenges such as resolution, material choice and print times. However, the methods and results reported here can serve as a foundation for future research, in particular in developing and testing more effective porous bed microstructures.