Centrifugal vs Reciprocating Comparison
| Parameter | Reciprocating | Centrifugal |
|---|---|---|
| Max Discharge | 12,000 psi (50,000 hyper) | 1,450 psi (horiz), 15,000 psi (barrel) |
| Max Flow | Limited by cylinders | 400,000 acfm |
| Turndown | 100% to 20% or lower | 20-30% (fixed), 40-50% (variable) |
| Reliability | Lower (more wearing parts) | 98-99% availability |
| Typical CR/stage | 1.2 to 4.0 | Depends on MW & stages |
Understand compressor types, selection criteria, and design considerations
Per GPSA Section 13 application maps, reciprocating is favored below ~1,000 acfm, centrifugal above ~10,000 acfm, and 1,000–10,000 acfm is an overlap region where either may work and a detailed evaluation is needed.
Key factors include inlet flow rate, discharge pressure, gas molecular weight, required turndown, reliability target, capital vs operating cost priority, and lead-time constraints. The calculator weights these per GPSA and industry guidelines.
Reciprocating is preferred for lower flow rates (<2,000 acfm), high discharge pressures (>1,500 psig), low molecular weight gases such as hydrogen, high turndown requirements, and applications with significant flow variation.
Centrifugal head per stage is inversely proportional to molecular weight, so hydrogen (MW=2) needs roughly 14.5x more stages than air for the same pressure ratio. Reciprocating positive-displacement machines are unaffected by MW and are typically the only practical choice for high-pressure hydrogen service.