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Ideal Single-Wax Solubility and Precipitation Calculator

Inspect ideal liquid/pure-solid equilibrium for one wax molecule using supplied fusion data and an explicit component material balance.

Inputs

Results

Calculate to view linked results. Default values are examples, not recommended operating inputs.

Calculation sequence

  1. Supply one identified wax solute's melting temperature and fusion enthalpy, with its initial mole fraction in a noncrystallizing ideal solvent. The default pair is the specific 309.6 K/69 kJ per mole NIST-listed eicosane measurement, not an average assembled from different references. Literature values vary; choose a consistent pair for your intended substance.
  2. Use the established chemicals solubility function for the ideal liquid and pure solid with zero fusion heat-capacity correction. The negative sign makes solubility decrease on cooling below Tm; test the Tm limit where saturation tends to one. No pressure correction or liquid activity coefficient is inferred from a petroleum SG.
  3. If the initial solute fraction exceeds saturation, remove pure-solid moles while conserving the solvent and total solute. The remaining liquid composition is not the original feed composition. Report precipitated moles per original mole, not a mass fraction or a solids volume fraction; no density or molecular-weight conversion is hidden.
  4. Sweep 250-400 K and include the requested operating temperature explicitly. The analytical onset solves the same ideal relation, but may fall below the plotted interval for a dilute feed. There is no coupling to a vapor flash, multiparaffin solid solution, deposition kinetics, viscosity rise or plugging model.
  5. Calculations run locally in a dedicated WebAssembly worker. The advanced Python/scientific engine is a roughly 33 MB first download, separate from ordinary calculators; it is self-hosted and version pinned. No composition or measurements are sent to a calculation server. Save and file backups retain canonical inputs, while CSV/PDF include returned tables and source notes. The worker is released after idle time and failures never return partial results.

Worked check

At 290 K the default eicosane fusion pair gives ideal saturation x about 0.1634. With initial wax fraction 0.30, some pure solid precipitates and the remaining liquid is at that saturation composition. The numbers are an ideal thermodynamic example, not an eicosane-in-crude solubility measurement.

Synthetic examples for reproducibility, not measured field results.

Assumptions and limitations

  • Ideal one-solute liquid plus pure crystalline solid; constant Hfus, deltaCp=0 and negligible pressure dependence. No petroleum multicut wax, solid solutions, nonideal activity model, asphaltenes or vapor equilibrium. An ideal onset is not a measured crude-oil WAT.
  • Software bounds T=250-400 K, Tm=280-380 K, Hfus=10-100 kJ/mol and initial wax fraction 0.001-0.9. These bounds do not validate fusion-data extrapolation. At/above pure melting temperature no solid is reported.
  • Equilibrium moles only; no mass/volume solid fraction, wall deposition, induction time, nucleation hysteresis or flow assurance approval. The chart and numerical closure do not establish applicability to an actual crude.

Implemented equations

Ideal liquid solubility and onset

ln⁡xsat=−ΔHfR(1T−1Tm)Tonset−1=Tm−1−RΔHfln⁡zwNS=max⁡(0,zw−xsat1−xsat)\begin{aligned}\ln x_{\rm sat}&=-\frac{\Delta H_f}{R}\left(\frac1T-\frac1{T_m}\right)\\T_{\rm onset}^{-1}&=T_m^{-1}-\frac R{\Delta H_f}\ln z_w\\N_S&=\max\left(0,\frac{z_w-x_{\rm sat}}{1-x_{\rm sat}}\right)\end{aligned}

Sources and maintenance

Published by PetroCalcHub Team. Implementation and source checks: . This does not claim independent expert review.

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