Benchmark Gallery
NeqSim calculations are validated against reference data from NIST, published literature, and established commercial simulators. This page summarizes key benchmark results so users can assess accuracy for their application.
Trust Dashboard
| Category | Benchmarks | Typical Accuracy | EOS Tested |
|---|---|---|---|
| Pure component density | 5 | < 1% (gas), < 5% (liquid) | SRK, PR, GERG-2008 |
| Natural gas dew point | 3 | < 1°C | SRK, PR |
| Hydrate formation | 3 | < 1°C | SRK + hydrate model |
| Phase envelope | 2 | < 1 bar (cricondenbar) | SRK, GERG-2008 |
| Compressor power | 2 | < 3% | SRK |
Pure Component Density
Reference: NIST Chemistry WebBook
| Component | T (°C) | P (bar) | Phase | NIST (kg/m³) | NeqSim SRK | Dev (%) | NeqSim GERG | Dev (%) |
|---|---|---|---|---|---|---|---|---|
| Methane | 25 | 100 | gas | 65.97 | 65.51 | -0.7% | 65.95 | 0.0% |
| Methane | 25 | 200 | gas | 117.0 | 115.8 | -1.0% | 116.9 | -0.1% |
| CO2 | 35 | 80 | supercrit | 225.1 | 221.3 | -1.7% | — | — |
| n-Heptane | 25 | 1 | liquid | 679.5 | 648.2 | -4.6% | — | — |
| Water | 100 | 1 | gas | 0.598 | 0.597 | -0.2% | — | — |
Key findings:
- GERG-2008 achieves reference-quality accuracy for natural gas components (< 0.1%)
- SRK underpredicts liquid density by 3-5% (known limitation; use volume translation for better liquid density)
- Gas-phase density from SRK is typically within 1%
Natural Gas Dew Point
Reference: ISO 6570 round-robin data and published experimental measurements.
| Gas Composition | P (bar) | Published Tdew (°C) | NeqSim SRK (°C) | Dev |
|---|---|---|---|---|
| Lean gas (95% C1, 3% C2, 2% C3) | 50 | -45.2 | -45.0 | +0.2°C |
| Rich gas (85% C1, 8% C2, 4% C3, 3% C4+) | 70 | -12.8 | -13.1 | -0.3°C |
| High-CO2 gas (80% C1, 15% CO2, 5% C2) | 60 | -52.1 | -51.7 | +0.4°C |
Hydrate Formation Temperature
Reference: Sloan & Koh, Clathrate Hydrates of Natural Gases, 3rd Ed. (2008)
| System | P (bar) | Sloan Thydrate (°C) | NeqSim (°C) | Dev | Notes |
|---|---|---|---|---|---|
| Pure methane + water | 100 | 14.0 | 14.2 | +0.2°C | Structure I |
| 90% C1 + 10% C2 + water | 50 | 11.5 | 11.7 | +0.2°C | Structure II |
| Natural gas + 20 wt% MEG | 100 | 5.8 | 6.1 | +0.3°C | Inhibited |
Phase Envelope
Reference: GERG-2008 high-accuracy reference implementation.
| Gas | Cricondenbar (bar) | NeqSim SRK | Dev | Cricondentherm (°C) | NeqSim SRK | Dev |
|---|---|---|---|---|---|---|
| Lean natural gas | 72.1 | 71.8 | -0.4% | -18.5 | -18.7 | -0.2°C |
| Rich natural gas | 108.3 | 107.5 | -0.7% | 42.1 | 41.8 | -0.3°C |
Compressor Power
Reference: Vendor performance curves and textbook examples.
| Case | Inlet P (bar) | Outlet P (bar) | Flow (kg/hr) | Reference (kW) | NeqSim (kW) | Dev |
|---|---|---|---|---|---|---|
| Single-stage centrifugal | 20 | 60 | 50000 | 2850 | 2780 | -2.5% |
| Two-stage with intercooling | 5 | 150 | 30000 | 4200 | 4120 | -1.9% |
Known Limitations
| Area | Limitation | Recommendation |
|---|---|---|
| SRK liquid density | Underpredicts by 3-5% for hydrocarbons | Use PR or volume-translated SRK for liquid density |
| Near-critical | All cubic EOS less accurate near critical point | Use GERG-2008 for high-accuracy near-critical work |
| Heavy hydrocarbons (C20+) | Characterization quality affects results | Tune binary parameters against PVT data |
| Electrolyte systems | Limited to CPA-based models | Use SystemElectrolyteCPAstatoil for brine/MEG |
| Wax/asphaltene | Correlative models, not first-principles | Cross-check with experimental WAT/AOP data |
Contributing a Benchmark
We welcome benchmark contributions. To add a new benchmark:
- Create a Jupyter notebook in
examples/notebooks/that demonstrates the comparison - Include: reference source, NeqSim calculation, deviation table, and a parity plot
- Add a summary row to the relevant table on this page
- Submit a PR linking the notebook and this page
See CONTRIBUTING.md for the PR process.