LNG BOG Compressor - Shaft Power

Adiabatic shaft-power estimate for a boil-off gas (BOG) compressor handling methane from atmospheric tank vapour to the DF-engine supply pressure.

LNGCompressorBOG

BOG mass flowkg/hSuction pressurebar(a)Discharge pressurebar(a)Suction temperatureKAdiabatic efficiency%

Adiabatic discharge temperature: 232.0K

Adiabatic gas power: 126.4kW

Shaft power: 168.5kW

Changing the inputs requires JavaScript. The calculator above shows its default inputs and result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

P_{shaft} = \frac{\dot m \cdot c_p \cdot T_1 \cdot \left[\left(\frac{p_2}{p_1}\right)^{\frac{k-1}{k}} - 1\right]}{\eta_{ad}}

Symbol	Meaning	Unit
$\dot m$	BOG mass flow	kg/s
$c_p$	Specific heat at constant pressure	kJ/kg·K
$T_1$	Suction temperature	K
$k$	Isentropic exponent
$\eta_{ad}$	Adiabatic efficiency

Source: GIIGNL Handbook - BOG Management; NIST Chemistry WebBook - methane

In short

Adiabatic shaft-power estimate for a boil-off gas (BOG) compressor handling methane from atmospheric tank vapour to the DF-engine supply pressure.

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