Distillation Curve Fitter

Converts petroleum distillation data between ASTM D86, ASTM D2887 (SimDist), and TBP using Riazi–Daubert correlations from the API Technical Data Book. Required columns: sample_id, method (D86 or D2887), vol_pct, temp_F.

CSV Input

Method: per-cut Riazi–Daubert power-law correlations T_target_R = a · (T_input_R)^b with separate (a, b) coefficients at 0, 10, 30, 50, 70, 90, 95 vol% evaporated. Input curve is piecewise-linear interpolated to standard cut points before conversion. Supported: D86 → TBP (API 3A2.1), D86 → D2887 (Riazi 1989), D2887 → D86 (inverse), D2887 → TBP (via D86 intermediate). Typical error 5–15°F per cut; valid range ~100–1100°F at 760 mm Hg. References: Riazi & Daubert (1986) Oil & Gas Journal; API Technical Data Book 6th Ed., Ch. 3; ASTM D86; ASTM D2887.

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