LNG Liquefaction
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LNG Liquefaction Efficiency Calculator

Specific power, compressor HP, and refrigerant inventory by cycle (C3MR · DMR · SMR · Cascade · AP-X · N₂)

Estimate LNG train specific power (kWh/kg LNG) and compressor shaft duty for the major liquefaction cycles, using published per-cycle benchmark specific power with an empirical correction for ambient temperature and cooling medium. Includes the reversible minimum-work reference (≈ 0.30 kWh/kg from ambient) and the measured real-cycle exergy-efficiency range (~30–40%). Benchmarks per Mokhatab et al., Handbook of LNG (cycle basis: GPSA §14 Refrigeration).

Feed & Plant

MMscfd
%
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Cycle

Ambient / Heat Sink

°F

📚 Theory

Why C3MR dominates, ambient penalty, refrigerant composition, the reversible work minimum and how to read real-cycle exergy efficiency.

Read Guide →

Equations

Specific power (benchmark lookup + empirical ambient correction):

SP = SPbase · (1 + 0.005 · (Tamb − 95 °F))

SPbase is a published per-cycle benchmark (not a cycle computation); water cooling applies a 3 % credit.

Compressor shaft power:

Pshaft (kW) = SP · mLNG (kg/hr)

Reversible (thermodynamic minimum) work — methane from ambient:

Wmin = (h₆ − h₁) − T₀(s₆ − s₁) = 1083 kJ/kg = 0.301 kWh/kg
Handbook of LNG Table 4-1 (Kanoglu et al. 2008); a fixed constant. Real-cycle exergy efficiency is ~30–40% (Handbook Ch. 4) — not computed per-input here, since published SP is for pressurized pipeline feed.

Related

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Cryogenic Demethanizer

Upstream NGL extraction.
🧊

Cascaded Refrigeration

Cycle internals.
💨

BOG (Boil-Off Gas)

LNG tank vapor balance.
🧊

Hydrate Prediction

Pre-treat requirement.