Executive Summary : | Objective: For simultaneous extraction and stripping with co-current flow of feed, solvent and strip solution with helical interfacial contact between both feed-solvent for extraction and solvent-strip solution for stripping in a multi-helical flow reactor. Since there is no phase breakup for either of these liquids, they simply get separated along their helical flow paths at the exit of the reactor; demonstration for extraction of Cu+2 ions from feed to LIX84 and then stripping into dilute H2SO4 in 3D printed multi-helical reactor Summary: Multi-helical flow reactors are novel in their geometrical 3D design in which several helical tubes are conjoined over a single axis. Typical cross-sectional shapes of different multi-helical designs are as shown in figures 1, 2, 10 and 11. With the flow of immiscible liquids in these geometries, the interphase renews continuously with the circumferential secondary flow of each liquid generated by the torsion of its helical flow path. Nevertheless, the interface remains stable through out the length of the reactor without any phase break-up up to a threshold limit of Deans number. This is a novel phenomenon unique to multi-helical geometry; and in fact it enhances the interphase mass transfer between immiscible phases. The renewal of interface has been experimentally evident. Also, the reactor has been demonstrated for the integration of two processes, i.e., for continuous extraction of metal ions from feed to solvent along helical flow paths and with complete phase separation at outlet as shown in figure 9. Here we propose further integration of the extraction with simultaneous stripping by adding more helical flow paths having interfacial contact between the flow of solvent and strip solution. To ensure for such integration, a demonstration for stability of interface with three liquid system has been done with parallel flow of water-oil-water system in a 3D printed six helices reactor. Now, we have to replace this three liquid system with that in practice for hydrometallurgy having interphase mass transfer of metal ions between feed-solvent and solvent-strip solution. Thus we can achieve the proposed process integration of extraction and stripping with subsequent phase separation at outlet. In fact with addition of stripping line, the solvent gets in-situ regeneration to result in even more concentration gradients across both the interfaces. We will begin with CFD simulation for parallel flow of feed-solvent-strip solution system inside multi-helical reactors and the same will be compared with experimental validation for efficiency of the integrated process and for assessment. |
