stages-thermo 0.1.0

Staged-separation (distillation) column solver: McCabe–Thiele, Ponchon–Savarit, FUG shortcut, and rigorous MESH methods, built on vle-thermo

stages-thermo

A staged-separation (distillation) learning library and fast steady-state column solver, built on vle-thermo.

import stages — walk the full pedagogical ladder of column methods (McCabe–Thiele → Ponchon–Savarit → Fenske–Underwood–Gilliland shortcut → rigorous MESH), each implemented from scratch and anchored to its textbook equations, with a granular, batch-capable API ("numpy for distillation columns"). All thermodynamics come from vle-thermo; this package adds none of its own.

pip install stages-thermo           # import name is `stages`
pip install "stages-thermo[plot]"   # + matplotlib for the staircase diagrams

Status: 0.1.x ships the first rung of the ladder — the binary McCabe–Thiele layer (Milestone 1): equilibrium curves from real thermodynamics, minimum reflux by geometric pinch detection (tangent pinches included), stage stepping with Murphree efficiency, total reflux, N(R), staircase plotting, and the binary column material balances. Multicomponent and rigorous MESH solvers land milestone by milestone — see the repo's ROADMAP.md. The API may still move before 1.0.

import stages

# Real thermodynamics from vle-thermo: Peng–Robinson benzene–toluene at 1 atm
# (light component first; units K / kPa absolute / mole fractions).
sys = stages.ThermoSystem.peng_robinson(["benzene", "toluene"])
curve = stages.EquilibriumCurve.from_thermo(sys, 101.325)

# Minimum reflux by pinch detection — tangent pinches included …
r = stages.rmin(curve, x_distillate=0.95, x_bottoms=0.05, z_feed=0.50, q=1.0)

# … then the full construction. Rich result objects, never bare numbers:
design = stages.mccabe_thiele(curve, 0.95, 0.05, 0.50, reflux=1.5 * r.r_min)
print(f"N = {design.n_stages:.2f} stages, feed stage {design.feed_stage}, "
      f"R_min = {r.r_min:.3f}")

design.stages          # every (x, y) stage corner
design.staircase       # the full polyline, ready to plot
design.rectifying      # operating lines as slope/intercept
r.pinch, r.tangent     # where the pinch sits, and whether it's a tangent pinch

# The staircase diagram (requires the [plot] extra):
# from stages import plotting
# plotting.plot_mccabe_thiele(design, curve, show_rmin=True)

Strongly non-ideal systems go through the γ-φ route — the same construction, different thermodynamics:

# van Laar methanol–water (the system validated in vle's Chapter IV notebooks).
mw = stages.ThermoSystem.van_laar(["methanol", "water"], 0.5853, 0.3458)
curve_mw = stages.EquilibriumCurve.from_thermo(mw, 101.325)

The executable learning path lives in the repo's notebooks/ — 01-mccabe-thiele.ipynb designs benzene–toluene and methanol–water columns end-to-end, with exercises.

The native core is a Rust crate (stages-thermo on crates.io) with PyO3 bindings; wheels are abi3 (cp310-abi3-*), so one wheel per (OS, arch) covers CPython 3.10+.

License

MIT © Miguel Roberto Jackson Ugueto