Design and fabrication of functionally graded packing for concentric heat integrated distillation columns (HIDiC)

Additive manufacturing (AM) and equation-based design enable the fabrication of functionally graded (FG) triply periodic minimal surface (TPMS) structures with enhanced heat transfer properties. This work introduces a methodology for designing radially graded TPMS packing for application in concentric heat-integrated distillation columns (HIDiC), where efficient radial heat transfer is required. The design ensures equivalent pressure drop across the gradient through an empirical model derived from gas-phase CFD simulations. Two strut-based FG configurations with opposite radial gradients were compared to a uniform reference structure. CFD results demonstrated that the configuration with thinner central struts and thicker peripheral struts provided up to 15% higher normalized heat transfer performance while maintaining similar pressure drop. A one-meter packing column, 3D printed in aluminum, exhibited a stable operation without flooding and achieved an average heat conductance of 667 ± 71 W °C⁻¹, outperforming the packing of reference, the stainless steel Super Raschig Rings. • A new methodology was developed for the design of radially graded TPMS packing. • Heat transfer improved with struts increasing from center outwards the packing wall. • Graded TPMS fabricated with heat conductance up to 667 W °C -1 without flooding.