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ABSTRACT
The simple and robust design of Taylor–Couette contactors has been attracting interests of research and industry since it was invented in the nineteenth century. Taylor–Couette contactors provide flexible operation under harsh operation conditions, as needed in liquid–liquid extraction. Nevertheless, industrial application is rather scarce, probably dating back to the historical limitation of Taylor–Couette flow being a gap phenomenon with limited hydraulic performance.
In order to improve the hydraulic performance of two-phase Taylor–Couette contactors, a research program was performed in pilot scale. Therefore, various parameters like dispersed phase holdup, residence time distribution as well as mean droplet size for varying radius ratio were related to the shaft centrifugation number.
Symbols used
Symbols
| B[m3 m−mh−m] | = | total hydraulic load |
| b[m] | = | = R – Ri = gap width |
| D[m] | = | column diameter (outer cylinder diameter) |
| Dax,c[m2 s−1] | = | axial dispersion coefficient of continuous phase |
| dm[mm] | = | mean droplet size |
| dSh[m] | = | shaft diameter (inner cylinder diameter) |
| Eθ[-] | = | dimensionless exit age distribution |
| g[m s−2] | = | gravity (9.81) |
| H[m] | = | active column height |
| N[-] | = | number of corresponding vessels in series |
| n[1 s−1] | = | rate of rotation |
| R[m] | = | column radius (outer cylinder radius) |
| Ri[m] | = | shaft radius (inner cylinder radius) |
| t[s] | = | time |
| = | mean residence time | |
| V[m3] | = | volume |
| w[rad s−1] | = | angular velocity |
| Z[-] | = | =(w2dSh)/(2g) = centrifugation number |
Greek symbols
| ε[W kg−1] | = | dissipation rate |
| η[-] | = | = Ri/R = radius ratio |
| Γ[-] | = | = H/b = aspect ratio |
| ρ[kg m−3] | = | density |
| ν[m2 s−1] | = | kinematic viscosity |
| φ[-] | = | dispersed phase holdup |
| θ[-] | = | dimensionless time (θ = t |
| ζ[-] | = | = b/dSh = gap ratio |
Subscripts
| c | = | continuous phase |
| d | = | dispersed phase |
Abbreviations
| CFD | = | computational fluid dynamics |
| RTD | = | residence time distribution |
| SST | = | ShellSol-T |
| TCR | = | Taylor–Couette reactor |
Supplementary material
Supplemental data for this article can be accessed here.