Development of Predictive Thermodynamic Model for Liquefaction of Natural Gas Using the C3-Mr Refrigeration Process

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Author(s) Dagde, Kenneth, K. | Okonkwo, Onochie, C.
Pages 1861-1871
Volume 2
Issue 11
Date November, 2012
Keywords natural gas, liquefaction, exergy, modeling, coefficient of performance, thermodynamic efficiency.

Abstract

This paper presents a propane precooled mixed refrigerant (C3-MR) liquefaction plant with 4 pressure levels of propane cooling operational in Nigeria and demonstrates the procedure for developing a thermodynamic model that predicts the liquefied natural gas (LNG) production rate. The model prediction was validated with plant data with a maximum deviation of 3%. The thermodynamic efficiency of the natural gas liquefaction plant was estimated to be 45.1%. Simulations reveals that LNG production rate for the C3-MR plant depends on cooling water supply temperature (1 ͦC rise results to 92 tonnes per day of LNG loss), thermodynamic efficiency of the overall liquefaction process (1% drop results to 215 tonnes per day of LNG loss), LNG outlet temperature (1 ͦC decrease results to 108 tonnes per day of LNG loss), LNG production to feed gas supply ratio (1% rise results to 37 tonnes per day rise in LNG), thermal efficiency of gas turbine drivers (1% drop results to 277 tonnes per day of LNG loss), ambient air temperature (1 ͦC drop results to 67 tonnes per day of LNG increase) and feed gas supply pressure.

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