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Polymer Devolatilization & Melt Transfer

A free-radical reactor feeds a real Flory-Huggins devolatilizer, then a transfer pipeline whose pressure drop comes from an actual non-Newtonian melt viscosity (3.4-power Mw scaling + Carreau shear-thinning) — not a flat guessed constant.

polymerdevolatilizationmelt viscositynon-newtonian
Concept

A continuous free-radical CSTR (real method-of-moments Mn/Mw/PDI) feeds a genuine Flory-Huggins devolatilizer that flashes above its real bubble point to strip residual monomer, and the still-viscous melt then transfers through a pipe whose pressure drop comes from an actual non-Newtonian melt viscosity — not a flat, user-guessed constant.

The math
Show the governing equations
η0=ηref(MwMw,ref)3.4(entangled-melt scaling law, Berry & Fox 1968)\eta_0 = \eta_{ref}\left(\dfrac{M_w}{M_{w,ref}}\right)^{3.4} \quad \text{(entangled-melt scaling law, Berry \& Fox 1968)}
η(γ˙)=η∞+(η0−η∞)[1+(λγ˙)2]n−12(Carreau shear-thinning)\eta(\dot\gamma) = \eta_\infty + (\eta_0-\eta_\infty)\left[1+(\lambda\dot\gamma)^2\right]^{\frac{n-1}{2}} \quad \text{(Carreau shear-thinning)}
γ˙wall=8vD(Newtonian-equivalent wall shear rate, pipe flow)\dot\gamma_{wall} = \dfrac{8v}{D} \quad \text{(Newtonian-equivalent wall shear rate, pipe flow)}
The zero-shear viscosity scales with the real 3.4-power Mw law from a caller-supplied reference point (there is no universal prefactor — every resin needs its own measured anchor); Carreau shear-thinning then derives the actual apparent viscosity fed into the same Darcy-Weisbach pressure-drop physics every other pipeline already uses.
Execution

Verified: genuinely sub-second

A pasted pitch claimed Aspen's polymer modules are "notoriously slow," implying this platform's equivalent would be dramatically faster without ever measuring it. Measured directly on this exact example (warm, second-pass — the fair comparison, since a real API worker has already paid every one-time init cost by the time a user opens a gallery card): 1.7 ms to solve reactor + devolatilizer + viscosity-coupled pipeline together. Real number, not a guess.

The polymerization devolatilization melt transfer flowsheet in the MaximaLabs workbench

The example as it opens in the workbench. Click to enlarge.

Launch in MaximaLabs Workspace
Bounded scope

What this doesn't model

  • The Flory-Huggins flash's own bubble-point search becomes numerically unreliable very close to the solvent's critical point at high polymer loading (found while building this example) — so this template's reactor conversion is tuned to a regime that flashes cleanly, not pushed to the near-total-solids melt a real bulk process reaches.
  • No die-swell/melt-fracture (normal-stress viscoelastic) behavior — viscosity only.