Economic evaluation of a new small-scale LNG supply chain using liquid nitrogen for natural-gas liquefaction

Abstract

This study proposes a new LNG (Liquefied Natural Gas) supply chain using liquid nitrogen to liquefy natural gas, which is reserved on a small scale or is being flared, and analyzes the life cycle cost (LCC) and life cycle profit (LCP) for the supply chain. Natural gas was liquefied with the latent heat of cryogenic liquid nitrogen (LN2) with no turbo-machine. The LNG was transported to the LN2 production site where LN2 was produced with the cold energy of the LNG. Then, LN2 was transferred to the LNG production site again. To verify the economics of this supply chain, the LCC and LCP were estimated with different design and operation conditions. This supply chain is significantly profitable because it uses the cold energy of both LN2 and LNG. The results of LCC and LCP show that the supply chain maximizes the profits when the pressure of the LNG product is approximately 7 bar. Additionally, the distance between the LNG production site and the LN2 production site is the dominant parameter that governs the economics of this supply chain.