doi: 10.3850/978-981-08-7614-2_IMPRES037

ABSTRACT

This paper presents a new natural gas liquefaction cycle which utilizes propane (C₃H₈), nitrogen monoxide (N₂O), and nitrogen gas (N₂) cycles. A liquefaction cycle with staged compression was designed and simulated using HYSYS software for improving cycle efficiency. This included a cascade cycle with a three-stage compression consisting of a C₃H₈, a N₂O and a N₂ cycle. These cycles were compared with an optimized staged compression process. The Compressor work, specific energy, and COP (Coefficient of Performance) of the cascade cycles were compared and analyzed. The new C₃H₈, N₂O and N₂ liquefaction cycle is also compared to other natural gas liquefaction cycles including the Phillips optimized cascade cycle and a multi-staged cascade cycle using a Propane, Ethylene and Methane. The COP (Coefficient of Performance) of the new cascade cycle which utilizes a three-stage compression process is 25% higher than that of basic single-stage cycle. Also, the new liquefaction cycle requires less power for the same liquefied natural gas (LNG) quantity produced by other methods. For example, up to 14.3% less power is consumed using the new method as opposed to the Phillips optimized cascade cycle under the same conditions of feed gas composition and liquefaction rate.

Keywords: Liquefaction, Cryogenic, LNG, Cascade, Refrigerating cycle.

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