Assay Characterization

TBP/ASTM D86/D1160 crude assay curves are cut into pseudocomponents via Riazi-Daubert (Tc/Pc/MW from NBP+SG), Edmister (acentric factor), Watson K, and a Kesler-Lee ideal-gas Cp(T) — the same pseudocomponent seam any EoS package flashes through.

thermodynamicspetroleumpseudocomponents

Concept

A crude/refinery feed isn't a list of named components — it's a TBP (True Boiling Point) distillation curve plus a specific-gravity profile. Assay characterization cuts that curve into equal-volume pseudocomponents, then regresses each cut's critical properties from just its normal boiling point and specific gravity.

The math

Show the governing equations

T_c,\ P_c,\ MW = f_{\text{Riazi-Daubert}}(NBP,\ SG)

\omega = f_{\text{Edmister}}(T_c,\ P_c,\ T_b)

K_w = \frac{NBP^{1/3}}{SG} \quad \text{(Watson characterization factor)}

Kesler-Lee then supplies an ideal-gas Cp(T) for each cut so it flashes like any other pseudocomponent through the same EoS seam.

Execution

Launch in MaximaLabs Workspace

ASSAY_INFEASIBLEA petroleum assay curve could not be characterized into pseudocomponents (e.g. a non-monotonic TBP curve).