Screw Compressor — Natural Gas Throughput
Positive-displacement screw-compressor performance estimator for the Frick TDS line and the Kobelco KS gas screws. Gas density via the Sutton + Dranchuk-Abou-Kassem real-gas method. Everything updates live as you change inputs.
Throughput
Referenced to 14.696 psia, 60 °F (the engine's standard state)
Real gas volume drawn in at suction
Power & discharge
Thermodynamic minimum at perfect Vᵢ match
Dry adiabatic reference — oil flooding keeps the real discharge 170–185 °F
Operating limits — TDSH 233XL
| Limit | Value | Basis |
|---|---|---|
| Max dry discharge temp | 230 °F | typical practice |
| Max pressure ratio | 7 : 1 | typical practice |
| Min differential (ΔP) | 30 psig | typical practice |
| Compressor casing rating | 400 psig | casing rating |
Generic oil-flooded screw limits are rules of thumb; casing, MAWP and package figures come from the sources shown under the model picker.
Capacity curve
Standard flow (MMSCFD)
Estimated brake power (BHP)
Show the full calculation & assumptions
Machine — TDSH 233XL, swept volume 0.45580 ft³/rev
- Displacement = swept × RPM × load = 0.45580 × 3550 × 100% = 1,618 ACFM (theoretical)
- × volumetric efficiency 0.899 = 1,455 ACFM actually drawn in
Gas at suction (64.7 psia, 70 °F)
- Specific gravity 0.65 → molar mass 18.83 lb/lbmol, k = 1.270
- Compressibility Z = 0.9894 → density 0.2166 lb/ft³
Throughput
- Mass flow = 1,455 ACFM × 0.2166 lb/ft³ × 60 min/hr = 18,903 lb/hr
- ÷ standard density 0.04974 lb/ft³ = 6,334 SCFM = 9.12 MMSCFD
Power (built-in Vᵢ = 2.57, mech. eff 0.93)
- Adiabatic (min) 561 HP · indicated 561 HP · brake 603 HP
Rough estimate. Volumetric efficiency is the dominant uncertainty (±5% → ±5% on flow). For a guaranteed selection, confirm against Frick CoolWare.
Read before you rely on these numbers
- This is a rough estimate, not a guaranteed compressor selection.
- Volumetric efficiency is the dominant assumption (±5% → ±5% on flow). Override it with a manufacturer value when you have one.
- The discharge temperature shown is the dry adiabatic reference; oil flooding keeps the real gas discharge much lower (~170–185 °F target).
- Geometry source per machine is shown under the model picker (Frick: service manual 070.250-IOM1 Table 2; Kobelco: see the provenance note for how the figure was derived).