Calculation methodology for segregation of solids in nonNewtonian carrier fluids Arno Talmon: Delft University of Technology & Deltares W.G.M. van Kesteren, D.R. Mastbergen and J.G.S. Pennekamp: Deltares B. Sheets: BARR Engineering “Feasibility of laminar flow” Problem & objective Problem: -Feasibility laminar flow transportation? -There is no technique that robustly predicts consequences of shear settling in laminar flow (transport capacity & hydraulic gradient). Developed: Modular modelling methodology; 2LM suspension & bottom layer, validated with experimental programs revealing advantages of gelled bed formation. Objective: explain why laminar flow may work Approach & application (s) Approach: -Identification of relevant physics. -Physical model tests. Contents presentation: - Flow configuration, - Shear settling - Gelled bed properties - Examples of application - Conclusions -Mathematical models for subprocesses. -Integration in calculation model(s): f.i. non-Newtonian two-layer model for pipes & open channel model. Applications: Long distance base metal hydrotransport, Hydraulic transport tailings, Hydraulic placement tailings (subareal beaching, submarine beaching), Dry stacking, Capping of contaminated soils, Pyroclastic flows, Horizontal Directional Drilling, Grouts and Mortars. Flow conditions & physical processes shear stresses = yield stress Shear settling of solids Particles co-rotate with the flow and settle slowly (J. Tunneling & Underground Space Technology, 2005) solid fluid at standstill in shear flow Carousel for horizontal shear flow: flow driven by rotating rigid lid. Shear test cell for concentrated suspensions Canadian J. Chemical Engineering 2014 Settling by particle size leads to S-curve. Distance between curves gives settling velocity. Shear test cell results Stokes settling formula: 2 1 (  s   f ) gd ws  18 a is equivalent with: Re = Ar/18 concentration single solids apparent viscosity carrier where Reynolds number: Re   s ws d a Archimedes number: Ar  hindered settling included (  s   f )  f gd 3 a 2 Bed formation: granular v/s gelled bed Granular bed (traditional with sand-water systems): Coulomb friction sand skeleton with (pipe) wall. Gelled bed (slimy layer) - particles do not touch - particles are suspended by yield stress. Coulomb Gelled beds slide ! granular (cv = ~60%) and ………………………….gelled beds (cv ~30% to 40 %) Concentration coarse in gelled beds [-] tau/tauystress carrier yield stress/yield gelled bed compacts at higher shear stress 10 Deltares carousel 9 MFT Gillies 2002, rotovisco 8 Inverse application of relative shear stress diagram to calculate solids concentration in gelled bed. Pennekamp 2010, vane test Acrivos analogy 7 Thomas 1999 6 5 4 3 same course as solids effect on rheology 2 1 0 0.1 0.2 0.3 0.4 0.5 cb [-] volumetric concentration coarse in bed Korea–Australia Rheology Journal 2010 Bed consistency map Effective transportation systems 100 a_cr=0.07  cr  0.07 carrier tauy [Pa] gelled bed gelled bed, carousel granular bed, carousel & Wan, 1985 10 HDD Blerick, Talmon and Mastbergen, 2004 TT Syncrude, Spelay, 2007 granular bed Strong NST, Sisson et al., 2012 1 Sunrise Dam, Fitton, 2007 Kimberley CTP, Pullum et al., 2010b Coal-clay, Thomas, 1979a 0.1 0.1 1 10 (rhos-rhoc)/1650 d [m m ] (ρ - ρ )/1650 d [mm] s f 100 Operational conditions compared to static settling condition:  y   cr s   f gd   Horizontal Directional Drilling: 2LM Sliding Bed Drilling rig Surface Exit point Entry point P-logger Drill head Bentonite sand-slurry Reamer diameter Drill string Bentonite fluid fluid pressure in bore hole [kPa] 700 2LM transient calculation Delft model 600 500 granular bed layer 400 gelled bed layer pressure logger 300 200 100 0 0 100 200 distance to rig side [m ] 300 400 Kimberley CTP Tailings pipeline Analysis with Delft model Table 1 Calculated hydraulic gradients w.r.t. Kimberley CTP. I [-] prototype measured 0.085 homogeneous 0.061 Coulomb (µ=0.45) 0.35 Gelled bed (µ=0) 0.085 Pullum et al. (2010b) 0.085 overpredicted Delft model Coulomb i.c.w. lumped parameter Thickened Tailings Open Channel Oil Sand Research Analytical model for solids depletion in laminar plug flow due to shear settling of coarse solids IOSTC conf 2012 Result: Fine Fluid Tailings that will disperse throughout pond Conclusions -Pay attention to the role of gelled bed under laminar flow. -Occurrence and physical properties are predictable. -If conditions are close to the transition gelled-granular bed, questions concerning Coulomb friction coefficient remain. -Laminar transportation is deemed possible by the very nature of gelled beds. -For beach and pond tailings segregated volumes of fines and coarse can be quantified. We aim at the entire system. Thank you! Selected references Sisson, R., Lacoste-Bouchet, P., Vera, M., Costello, M., Hedblom, E., Sheets, B., Nesler, D., Solseng, P., Fandrey, A., Van Kesteren, W., Talmon, A. and Sittoni, L. (2012), An analytical model for tailings deposition developed from pilot-scale testing, in: D. Sego, G.W. Wilson and N. Beier (eds.) proc. 3rd International Oil Sands Tailings Conference, Edmonton, Alberta, Canada, December 2-5, 2012, pp.53-63. Talmon, A.M. and Mastbergen, D.R. (2004) Solids transport by drilling fluids: Horizontal Directional Drilling, in proceedings 12th International Conference on Transport and Sedimentation of Solid Particles, Praque, pp.641-649. Talmon, A.M. and Huisman, M. (2005) Fall velocity of particles in shear flow of drilling fluids, J. Tunnelling and Underground Space Technology, including Horizontal Directional Drilling, Vol. 20(2), pp.193-201. Talmon, A.M. (2010) Regarding “Are tube viscometer data valid for suspension flows” [Letter to the editor], KoreaAustralia Rheology Journal, Vol. 22(3), pp.169-171. Talmon, A.M., Kesteren, W.G.M. van, Sittoni, L., and Hedblom, E. (2014) Shear cell tests for quantification of tailings segregation, Canadian J. Chemical Engineering, vol.92, pp.362-373.